Multi-component putter

Abstract

Described herein are embodiments of a multi-component putter comprising an upper portion and a lower portion. The upper portion is formed from a first material having a first density and the lower portion is formed from a second material having a second density. The first density is less than the second density. The upper portion is secured to the lower portion by an adhesive or a combination of an adhesive and a geometric interlocking structure. The multi-component putter design provides improved forgiveness and moment of inertia compared to putters formed from a single material.

Description

[Technical Field]

[0001] Cross-references to related applications This claims the interests of U.S. Provisional Patent Application No. 63 / 260,612 filed on 26 August 2021, U.S. Provisional Patent Application No. 63 / 203,257 filed on 14 July 2021, U.S. Provisional Patent Application No. 63 / 190,691 filed on 19 May 2021, and U.S. Provisional Patent Application No. 63 / 130,312 filed on 23 December 2020. This is a continuation in part of U.S. Patent Application No. 17 / 444,468, filed on 4 August 2021, which is a continuation in part of U.S. Design Application No. 29 / 720,679, filed on 15 January 2020, issued as U.S. Patent No. D930,097 on 7 September 2021, and a continuation of U.S. Patent Application No. 17 / 243,338, filed on 28 April 2021, which is a continuation of U.S. Patent Application No. 16 / 590,270, filed on 1 October 2019, issued as U.S. Patent No. 11,020,640 on 1 June 2021, and claims the interests of U.S. Provisional Patent Application No. 62 / 739,747, filed on 1 October 2018, all of which are incorporated herein in full by reference.

[0002] This disclosure relates in general to golf clubs, and more specifically to multi-component putter-type golf club heads. [Background technology]

[0003] Many putter-type golf club heads utilize weight distribution devices to alter the club head's center of gravity or increase its moment of inertia (MOI). Common weight distribution devices include removable weight ports in the heel and toe areas of the sole, weighted faceplate inserts, inserts for the back of a portion of the face, and attachments for the perimeter of the toe and heel areas. Putter-type golf club heads, in particular, often utilize weight ports in the heel and toe areas. These weight ports can be removable by fasteners or permanently attached by various epoxy, adhesive, or machining methods. The use of weight ports in the heel and toe areas increases the MOI of the putter head, resulting in a straighter ball path after impact.

[0004] While these weight ports in the heel and toe areas increase the MOI, they also increase the weight of the golf club head, making it heavier than the ideal weight for a putter. Furthermore, attaching weight ports to a golf club putter head requires a cavity or recess to accommodate these weight ports during manufacturing, thereby increasing the cost of the putter head. In addition, weight ports can cause vibrations within the cavity or recess during impact when the golf club head contacts the golf ball. These cavities and recesses also alter the sound of the club head, creating a hollow sound within the club head. In this field, in order to produce consistent putting, it is necessary to develop a putter that is pleasing to the user's eye, has a desirable sound, has ambient weighting, and possesses the ideal weight for balanced putting. [Brief explanation of the drawing]

[0005] [Figure 1A] This is an exploded view of a blade putter-type golf club head.

[0006] [Figure 1B] Figure 1A is an isometric view of a blade putter-type golf club head.

[0007] [Figure 1C] Figure 1A is a side view of a blade putter-type golf club head.

[0008] [Figure 2A] This is an exploded view of a blade putter-type golf club head.

[0009] [Figure 2B] Figure 2A is an isometric view of a blade putter-type golf club head.

[0010] [Figure 2C] Figure 2A is a side view of a blade putter-type golf club head.

[0011] [Figure 3A] This shows an exploded view of a crescent-shaped putter-type golf club head.

[0012] [Figure 3B] Figure 3A shows an isometric view of the crescent-shaped putter-type golf club head.

[0013] [Figure 3C] Figure 3A shows a side view of the crescent-shaped putter-type golf club head.

[0014] [Figure 4A] This shows an exploded view of a semi-circular putter-shaped golf club head.

[0015] [Figure 4B] Figure 4A is an isometric view of a semicircular putter-shaped golf club head.

[0016] [Figure 4C] Figure 4A is a side view of a semicircular putter-shaped golf club head.

[0017] [Figure 5A] Here is an exploded view of another semi-circular putter-shaped golf club head.

[0018] [Figure 5B] Figure 5A is an isometric view of a semicircular putter-shaped golf club head.

[0019] [Figure 5C] Figure 5A is a side view of a semicircular putter-shaped golf club head.

[0020] [Figure 6A] This shows an exploded view of a wing-type putter golf club head.

[0021] [Figure 6B] Figure 6A is an isometric view of the wing-type putter golf club head.

[0022] [Figure 6C] Figure 6A shows a side view of the wing-type putter golf club head.

[0023] [Figure 7A] This shows an exploded view of a spade-shaped putter-type golf club head.

[0024] [Figure 7B] Figure 7A shows an isometric view of a spade-shaped putter-type golf club head.

[0025] [Figure 7C] Figure 7A shows a side view of a spade-shaped putter-type golf club head.

[0026] [Figure 7D] Figure 7A shows a perspective view of the bottom of a spade-shaped putter-type golf club head.

[0027] [Figure 8A]This is an exploded view of a T-shaped putter-type golf club head with a perimeter span.

[0028] [Figure 8B] Figure 8A is an isometric view of a T-shaped putter-type golf club head with the peripheral span shown.

[0029] [Figure 8C] Figure 8A is a side view of a T-shaped putter-type golf club head with a peripheral span.

[0030] [Figure 8D] Figure 8A is a bottom perspective view of a T-shaped putter-type golf club head with the peripheral span shown.

[0031] [Figure 9A] This is an exploded view of a dual-rail putter-type golf club head.

[0032] [Figure 9B] Figure 9A is an isometric view of a dual-rail putter-type golf club head.

[0033] [Figure 9C] Figure 9A is a side view of a dual-rail putter-type golf club head.

[0034] [Figure 9D] Figure 9A is a bottom perspective view of a dual-rail putter-type golf club head.

[0035] [Figure 10A] This shows an exploded view of a circular putter-shaped golf club head.

[0036] [Figure 10B] Figure 10A is an isometric view of a circular putter-shaped golf club head.

[0037] [Figure 10C] Figure 10A is a side view of a circular putter-shaped golf club head.

[0038] [Figure 10D] Figure 10A is a bottom perspective view of a circular putter-shaped golf club head.

[0039] [Figure 11A] This shows an exploded view of a putter-type golf club head with a single-component system striking face insert.

[0040] [Figure 11B] This shows an exploded view of a putter-type golf club head with a striking face that has a two-component system.

[0041] [Figure 11C] This shows a front view of a putter-type golf club head equipped with a striking face insert according to a third embodiment.

[0042] [Figure 12A] This shows a top perspective view of a two-part putter-type clubhead, including the sole plate.

[0043] [Figure 12B] Figure 12A shows the sole diagram of a two-part putter.

[0044] [Figure 12C] Figure 12A shows an exploded view of the two-part putter.

[0045] [Figure 12D] Figure 12A shows a bottom view of the two-part putter with the lower section removed.

[0046] [Figure 12E] Figure 12A shows the heel diagram of the two-part putter.

[0047] [Figure 13A] This shows a rear perspective view of a two-part putter-type club head with a pocket.

[0048] [Figure 13B] Figure 13A shows an exploded view of the two-part putter.

[0049] [Figure 13C] Figure 13A shows the sole diagram of a two-part putter.

[0050] [Figure 13D] Figure 13A shows the heel of the two-part putter with the lower section removed.

[0051] [Figure 13E] Figure 13A shows the toe diagram of the two-part putter with the lower section removed.

[0052] [Figure 14A] The image shows a top perspective view of a two-part putter head including a ball retrieval mechanism according to the first embodiment.

[0053] [Figure 14B] Figure 14A shows a perspective view of the putter head from below.

[0054] [Figure 14C] Figure 14A shows an exploded view of the putter head.

[0055] [Figure 14D] Figure 14A shows an exploded view of the putter head.

[0056] [Figure 14E] A perspective view of the bottom of a two-part putter head, including a ball retrieval mechanism according to a second embodiment, is shown.

[0057] [Figure 14F] A perspective view of the bottom of a two-part putter head, including a ball retrieval mechanism according to a third embodiment, is shown.

[0058] [Figure 14G] A perspective view of the bottom of a two-part putter head including a ball retrieval mechanism according to the fourth embodiment is shown.

[0059] [Figure 14H] A perspective view of the bottom of a two-part putter head, including a ball retrieval mechanism according to the fifth embodiment, is shown.

[0060] [Figure 15A] This shows a rear perspective view of a two-part putter head, including the ball outline alignment aid.

[0061] [Figure 15B] Figure 15A shows a rear perspective exploded view of the putter head in two parts.

[0062] [Figure 15C] Figure 15A shows a two-part view of the putter head from below.

[0063] [Figure 15D] Figure 15A shows a top view of a two-part putter head, including the ball outline alignment aid.

[0064] [Figure 15E] The image shows a top view of a two-part putter head including a ball outline alignment assist section according to the second embodiment.

[0065] [Figure 15F] The image shows a top view of a two-part putter head including a ball outline alignment assist section according to a third embodiment.

[0066] [Figure 16A] A front perspective view of the putter head, including separate toe and heel masses, is shown.

[0067] [Figure 16B] Figure 16A shows a rear perspective exploded view of the putter head.

[0068] [Figure 16C] Figure 16A shows the sole of the putter head.

[0069] [Figure 16D] Figure 16A shows the underside view of the toe mass and heel mass of the putter head.

[0070] [Figure 17A] This shows a rear perspective exploded view of a two-part blade type putter head according to the first embodiment.

[0071] [Figure 17B] This shows a rear perspective exploded view of a two-part blade type putter head according to a second embodiment, which has an opening that penetrates the striking face.

[0072] [Figure 17C] Figure 17A shows a rear perspective view of a two-part blade-type putter head.

[0073] [Figure 17D] Figure 17A shows a front perspective view of the upper part of a two-part blade-type putter head.

[0074] [Figure 17E] Figure 17B shows a front perspective view of a two-part blade-type putter head.

[0075] [Figure 18A] This shows a rear perspective exploded view of a three-part putter head according to one embodiment.

[0076] [Figure 18B] Figure 18A shows a rear perspective view of the three-part putter head.

[0077] [Figure 18C] Figure 18A shows a perspective view of the bottom of the three-part putter head with the lower section removed.

[0078] [Figure 18D] Figure 18A shows a diagram of the sole of a three-part putter head.

[0079] Other aspects of this disclosure will become apparent from the detailed description and accompanying drawings. [Modes for carrying out the invention]

[0080] I. Putter Golf Club Head This specification describes a two-part putter head having an upper made of a first material, such as a low-density metal (i.e., aluminum, but not limited thereto), and a lower made of a second material, such as a high-density metal (i.e., steel, but not limited thereto). The upper has a crown that extends from the striking face to the back edge. This upper is fixed to the lower and is further from the ground plane than the lower. In most embodiments, the lower is less than 35% of the total real volume of the putter head, but more than 45% of the mass. The lower provides the perimeter structure and sole. This combination of perimeter structure and high-density lower results in at least a 30% increase in MOI compared to putters with the same volume, mass, and single-material construction (i.e., steel putters or single-material putter milling such as single-material putter investment casting).

[0081] The lower part of the two-part putter head further includes a sole plate. The sole plate is formed of a high-density material. As will be described in more detail below, the two-part putter head includes an upper part and a lower part including the sole plate. The lower part including the sole plate features a mass structure, ball retrieval mechanism, and / or ball outline alignment aid to enhance the putting experience. The putter head with the upper part and the lower part including the sole plate is pleasing to the eye while increasing perimeter weighting, MOI, and forgiveness. The putter head with the upper part and the lower part including the sole plate further provides consistent ball speed and ball travel distance for repeated putts.

[0082] The terms “first,” “second,” “third,” and “fourth” in the detailed description and claims are used to distinguish between similar elements, where applicable, and not necessarily to describe a specific sequential or chronological order. The terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that the embodiments described herein allow for sequences of operation other than those illustrated or otherwise described herein. Furthermore, the terms “equipped with” and “possessing,” and any variations thereof, are intended to cover non-exclusive inclusion, allowing a process, method, system, article, device, or apparatus containing a list of elements to include other elements that are not explicitly enumerated or are inherently present in such a process, method, system, article, device, or apparatus, but are not necessarily limited to those elements.

[0083] Terms such as “left,” “right,” “forward,” “backward,” “upward,” “downward,” “upward,” “downward,” “upward,” and “downward” in the description and claims are used for descriptive purposes and are not necessarily intended to describe permanent relative positions. Terms used in this way are interchangeable under appropriate circumstances. Therefore, it should be understood that embodiments of the apparatus, methods, and / or products described herein may operate in orientations different from, for example, those shown herein or otherwise described herein.

[0084] Before any embodiment of this disclosure is described in detail, it should be understood that in its application, this disclosure is not limited to the component details or construction and arrangement as described in the following description or illustrated in the drawings. This disclosure can support other embodiments and may be practiced or implemented in a variety of ways.

[0085] In many embodiments, the golf club head may include a putter-type golf club head (putter-type golf club head 100, 200, 300, 400, etc.). Figures 1-12B show several embodiments of a putter-type golf club head having an upper and lower section made separately from different materials and joined together. The putter-type golf club head may be a mallet-type putter head, a mid-mallet-type putter head, a blade-type putter head, a high-MOI putter head, or any other type of putter-type golf club head.

[0086] In many embodiments, a putter-type golf club head can have a loft angle of less than 10 degrees. In many embodiments, the loft angle of the club head may be 0-5 degrees, 0-6 degrees, 0-7 degrees, or 0-8 degrees. For example, the loft angle of the club head may be less than 10°, less than 9°, less than 8°, less than 7°, less than 6°, or less than 5°. As a further example, the loft angle of the club head may be 0 degrees, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, or 10 degrees.

[0087] A putter-type golf club head includes an upper and lower section. The golf club head may include a toe end and a heel end opposite the toe end. A putter-type golf club head may include a striking face. A putter-type golf club head may have a rear wall opposite the striking face. Furthermore, a putter-type golf club head may include an alignment mechanism. Additionally, a putter-type golf club head may include a hosel attached to the heel end of the club head. The hosel may be attached to the center of the putter-type golf club head. The hosel may be attached to the heel end of the putter-type golf club head. The hosel may be formed integrally with the upper section of the putter-type golf club head. The hosel may be formed integrally with the lower section of the putter-type golf club head.

[0088] The upper part is made of the first material. The lower part is made of the second material. The first material is different from the second material. The first material has a first density. The second material has a second density. The density of the first material is not the same as the density of the second material.

[0089] In many embodiments, the putter-type golf club head can have a mass in the range of 340 to 385 grams. In other embodiments, the mass of the putter-type golf club head can be in the range of 340 to 345 grams, 345 to 350 grams, 350 to 355 grams, 355 to 360 grams, 360 to 365 grams, 365 to 370 grams, 370 to 375 grams, 375 to 380 grams, or 380 to 385 grams. In some embodiments, the mass of the putter-type golf club head can be 340 grams, 341 grams, 342 grams, 343 grams, 344 grams, 345 grams, 346 grams, 347 grams, 348 grams, 349 grams, 350 grams, 351 grams, 352 grams, 353 grams, 354 grams, 355 grams, 356 grams, 357 grams, 358 grams, 359 grams, 360 grams, 361 grams, 362 grams, 363 grams, 364 grams, 365 grams, 366 grams, 367 grams, 368 grams, 369 grams, 370 grams, 371 grams, 372 grams, 373 grams, 374 grams, 375 grams, 376 grams, 377 grams, 378 grams, 379 grams, 381 grams, 382 grams, 383 grams, or 384 grams.

[0090] In many embodiments, a putter-type golf club head can be configured with a club head volume in the range of 25cc to 125cc. In some embodiments, the club head volume may be in the range of 25cc to 30cc, 30cc to 35cc, 35cc to 40cc, 40cc to 45cc, 45cc to 50cc, 50cc to 55cc, 55cc to 60cc, 60cc to 65cc, 65cc to 70cc, 70cc to 75cc, 75cc to 80cc, 80cc to 85cc, 85cc to 90cc, 90cc to 95cc, 95cc to 100cc, 100cc to 105cc, 105cc to 110cc, 110cc to 115cc, 115cc to 120cc, or 120cc to 125cc. In one embodiment, the club head volume may be in the range of 40cc to 110cc. In some embodiments, the club head volume may be greater than 25cc, greater than 50cc, greater than 75cc, or greater than 100cc.

[0091] In some embodiments, the putter-type golf club head may include a striking face made of a first material. In other embodiments, the striking face may be made of a second material. In these embodiments, the material of the striking face may be any or a combination of the following materials: 8620 alloy steel (7.83 g / cc), S25C steel (7.85 g / cc), carbon steel (7.85 g / cc), maraging steel (8.00 g / cc), 17-4 stainless steel (7.81 g / cc), 303 stainless steel (8.03 g / cc), 304 stainless steel (8.00 g / cc), stainless steel alloy (7.75 g / cc-8.05 g / cc), tungsten (19.25 g / cc), aluminum (2.70 g / cc), aluminum alloy (2.64 g / cc-2.81 g / cc), ADC-12 (2.75 g / cc). In some embodiments, the striking face can be integrally formed on the upper part. In other embodiments, the striking face can be integrally formed on the lower part. The striking face can be integrally formed on the club head by co-molding, injection molding, casting, additive manufacturing, or other molding processes.

[0092] Figures 11A–11C show various striking face mechanisms 1100 used in the multi-component putter described herein. As will be described in more detail below, the striking face mechanism 1100 may include a single-component system, a two-component system, or a single-component system combined with a metal part. A single-component system includes a single striking face insert or component. A two-component system includes multiple striking face inserts or components. In many embodiments, the striking face mechanism 1100 may include a striking face insert. In these embodiments, the striking face is formed independently before being coupled to the club head. The sides of the striking face insert that contact the club head may constitute geometry complementary with respect to the geometry of the corresponding portion of the club head that contacts the striking face. In some embodiments, the striking face insert may be made of a first or second material. In other embodiments, the striking face insert may be made of a third material. In some embodiments, the striking face insert may be formed integrally with the upper or lower part. In other embodiments, the striking face insert can be formed separately from both the top and bottom.

[0093] The striking face can be fixed to the club head by being integrally formed with a portion of the club head or by fastening means. In some embodiments, the striking face is fixed to the top. In these embodiments, the top may define an insert cavity 1110 at the front of the top. The top insert cavity 1110 is configured to receive the striking face insert. Furthermore, in these embodiments, once the striking face insert is fixed to the top, the top surrounds and mates with the insert cavity 1110. In other embodiments, the striking face may be fixed to the bottom. In these embodiments, the bottom may include an insert cavity (not shown). The bottom insert cavity functions to receive the striking face insert. Furthermore, in these embodiments, once the insert is fixed to the bottom, the bottom surrounds and mates with the insert cavity. The striking face can be fixed by adhesive, such as adhesive, ultra-high bonding (VHB®) tape, epoxy, or another adhesive. Alternatively or additionally, the striking face may be secured by welding, soldering, screws, rivets, pins, mechanical interlocking structures, or other fastening methods.

[0094] The striking face insert can be constructed from any one of the following materials or a laminated combination of them: aluminum, stainless steel, copper, thermoplastic copolyester elastomer (TPC), thermoplastic elastomer (TPE), thermoplastic urethane (TPU), steel, nickel, TPU / aluminum, TPE / aluminum, plastic / metal screen insert, polyethylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, PEBAX®, or other preferred materials. PEBAX® is a polyether block amide, a thermoplastic elastomer made from soft polyether and hard polyamide. The hard polyamide may include nylon. PEBAX® may contain different compounds corresponding to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, PEBAX® may include PEBAX® 4033 (Arkema, Paris France) or PEBAX® 6333 (Arkema, Paris France). PEBAX® 4033 (Arkema, Paris France) contains tetramethylene oxide (53 wt%) and nylon 12. PEBAX® 6333 (Arkema, Paris France) contains nylon 11. In some embodiments, the face insert may contain materials such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials, or any combination thereof.

[0095] PEBAX® may contain polyether by volume percentage. In some embodiments, PEBAX® may contain 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 30% to 50%, 30% to 60%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% by volume of polyether. For example, PEBAX® may contain 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% by volume of polyether. In some embodiments, PEBAX® may contain 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% by volume of polyamide. For example, PEBAX® may contain 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% by volume of polyamide. The hardness of PEBAX® decreases as the percentage of polyether increases. The hardness of PEBAX® increases as the percentage of polyamide increases. For example, PEBAX® 4033 (Arkema, Paris France) may contain 40% to 60% by volume of polyether and 15% to 30% by volume of polyamide. For example, PEBAX® 6333 (Arkema, Paris France) may contain 15% to 30% by volume of polyether and 40% to 60% by volume of polyamide.

[0096] In many embodiments, PEBAX® may have hardnesses ranging from Shore 25D to Shore 75D. In some embodiments, the hardness of PEBAX may range from Shore 25D to Shore 35D, Shore 35D to Shore 45D, Shore 36D to Shore 44D, Shore 38D to Shore 42D, Shore 45D to Shore 55D, Shore 55D to Shore 65D, Shore 56D to Shore 64D, Shore 60D to Shore 65D, or Shore 65D to Shore 75D. For example, the hardness of PEBAX may be Shore D25, 30, 35, 40, 45, 50, 55, 60, 65, or 70.

[0097] In many embodiments, PEBAX® 4033 (Arkema, Paris France) may have a lower hardness than PEBAX® 6333 (Arkema, Paris France). In many embodiments, PEBAX® 4033 (Arkema, Paris France) may have a hardness range of Shore 35D to Shore 55D. In some embodiments, PEBAX® 4033 (Arkema, Paris France) may have a hardness range of Shore 38D to Shore 42D, or Shore 39D to Shore 41D. For example, PEBAX® 4033 (Arkema, Paris France) may have a Shore D hardness of 40. In many embodiments, PEBAX® 6333 (Arkema, Paris France) may have a hardness range of Shore 50D to Shore 75D. In some embodiments, PEBAX® 6333 (Arkema, Paris France) can include hardness ranges of Shore 55D to Shore 70D, or Shore 60D to Shore 65D. For example, PEBAX® 6333 (Arkema, Paris France) can include a Shore D hardness of 63.

[0098] As shown in Figure 11A, the striking face mechanism 1100 may include a striking face insert system 1120. The striking face insert system 1120 may be a single-component system including a ball striking layer 1122 and an adhesive layer 1124. The striking face insert 1120 is configured to be bonded to the insert cavity 1110 via the adhesive layer 1124. The striking face insert 1120 may include polymer-type materials as described in this disclosure. The striking face insert 1120 may include PEBAX® as described in this disclosure.

[0099] As shown in Figure 11B, the striking face mechanism 1100 may include a striking face insert system 1130. The striking face insert system 1130 may be a two-component system including a ball striking face plate 1132 and a face insert base 1134. The striking face insert system 1130 having a two-component system is configured to be received into an insert cavity 1110 via one or more adhesive layers. The ball striking face plate 1132 of the striking face insert 1130 may include a first insert material. The face insert base 1134 of the striking face insert 1130 may include a second insert material. In many embodiments, the first insert material of the ball striking face plate 1132 and the second insert material of the face insert base 1134 may be different. In some embodiments, the first insert material of the ball striking face plate 1132 and the second insert material of the face insert base 1134 may be the same. In many embodiments, the first insert material of the ball striking faceplate 1122 may include a polymer-type material. In some embodiments, the first insert material of the ball striking faceplate 1122 may include a metal material. In many embodiments, the second insert material of the face insert base 1134 may include a polymer-type material.

[0100] The first insert material may include metals such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials, or any combination thereof.

[0101] The first or second insert material may include polymer-type materials. Polymer-type materials may include polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, or any other polymer-type material. In many embodiments, the face insert may include PEBAX®. More specifically, PEBAX® is a polyether block amide, a thermoplastic elastomer made from a flexible polyether and a rigid polyamide. The rigid polyamide may include nylon. PEBAX® may include different compounds corresponding to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, PEBAX® may include PEBAX® 4033 (Arkema, Paris France) or PEBAX® 6333 (Arkema, Paris France). PEBAX® 4033 (Arkema, Paris France) contains tetramethylene oxide (53 wt%) and nylon 12. PEBAX® 6333 (Arkema, Paris, France) contains nylon 11. The first and second insert materials may contain the same polyether percentages, polyamide percentages, or Shore D hardness values ​​as described above.

[0102] The ball striking faceplate 1132 of the striking face insert 1130 may have a thickness. In many embodiments, the thickness of the ball striking faceplate 1132 can be in the range of 0.015 to 0.115 inches. In some embodiments, the thickness of the ball striking faceplate 1132 can be in the range of 0.015 to 0.045 inches, 0.020 to 0.050 inches, 0.025 to 0.055 inches, 0.050 to 0.100 inches, 0.055 to 0.105 inches, 0.060 to 0.110 inches, or 0.065 to 0.115 inches. In some embodiments, the thickness of the ball striking faceplate 1132 can be at least 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.10, 0.105, 0.110, or 0.115 inches. In some embodiments, the thickness of the ball striking faceplate 1132 may be 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.10, 0.105, 0.110, or 0.115 inches or more. In some embodiments, the thickness of the ball striking faceplate 1132 may be 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.10, 0.105, 0.110, or 0.115 inches or less. For example, the thickness of the ball-hitting faceplate 1132 can be 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, 0.045, 0.050, 0.055, 0.060, 0.065, 0.070, 0.075, 0.080, 0.085, 0.090, 0.095, 0.10, 0.105, 0.110, or 0.115 inches.

[0103] In other embodiments, the thickness of the ball striking faceplate 1132 can be in the range of 0.115 to 0.40 inches. In some embodiments, the thickness of the ball striking faceplate 1132 may be in the range of 0.115 to 0.20 inches, 0.15 to 0.30 inches, 0.20 to 0.30 inches, 0.25 to 0.35 inches, or 0.30 to 0.40 inches. In some embodiments, the thickness of the ball striking faceplate 1132 can be at least 0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inches. In some embodiments, the thickness of the ball striking faceplate 1132 may be 0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inches or more. In some embodiments, the thickness of the ball striking faceplate 1132 can be 0.15 inches, 0.20 inches, 0.25 inches, 0.30 inches, 0.35 inches, or 0.40 inches or less. For example, the thickness of the ball striking faceplate 1132 can be 0.15 inches, 0.20 inches, 0.25 inches, 0.30 inches, 0.35 inches, or 0.40 inches.

[0104] The face insert base 1134 of the striking face insert 1130 may have a thickness. In many embodiments, the thickness of the face insert base 1134 may be in the range of 0.05 to 0.20 inches. In some embodiments, the thickness of the face insert base 1134 may be in the range of 0.05 to 0.10 inches, or 0.10 to 0.20 inches. In some embodiments, the thickness of the face insert base 1134 may be at least 0.05 inches, 0.10 inches, 0.15 inches, or 0.20 inches. In some embodiments, the thickness of the face insert base 1134 may be 0.05 inches, 0.10 inches, 0.15 inches, or 0.20 inches or more. In some embodiments, the thickness of the face insert base 1134 may be 0.05 inches, 0.10 inches, 0.15 inches, or 0.20 inches or less. For example, the thickness of the face insert base 1134 can be 0.05 inches, 0.10 inches, 0.15 inches, or 0.20 inches.

[0105] In other embodiments, the thickness of the face insert base 1134 can be in the range of 0.20 to 0.80 inches. In some embodiments, the thickness of the face insert base 1134 can be in the range of 0.20 to 0.50 inches, 0.30 to 0.60 inches, 0.40 to 0.70 inches, or 0.50 to 0.80 inches. In some embodiments, the thickness of the face insert base 1134 can be in the range of 0.20 to 0.40 inches, 0.30 to 0.50 inches, 0.40 to 0.60 inches, 0.50 to 0.70 inches, or 0.60 to 0.80 inches. In some embodiments, the face insert base 1134 of the striking face insert 1130 can be at least 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, or 0.80 inches. In some embodiments, the face insert base 1134 of the striking face insert 1130 may be 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, or 0.80 inches or less. For example, the thickness of the face insert base 1134 can be 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, or 0.80 inches.

[0106] As shown in Figure 11C, the striking face mechanism 1100 may include a striking face insert system 1140. The striking face insert system 1140 includes a striking face insert 1144 and a metal portion 1142. The striking face insert 1144 includes the single-component system described above. The metal portion 1142 surrounds the striking face insert 1144. The striking face insert 1144 may be formed from a polymer material as described herein. The striking face insert 1144 is further surrounded by an epoxy boundary 1146. The epoxy boundary 1146 extends around the periphery of the striking face insert 1144. The combination of the striking face insert 1144 formed from a polymer-type material and the epoxy boundary 1146 can provide an enhanced feel and sound upon impact with a golf ball. Furthermore, removing material from the striking face or top to accommodate the striking face insert 1144 reduces the weight of the putter head in or near the central region of the putter head. By removing material from the central and / or front regions of the putter head, more weight can be placed around the periphery of the putter head, thereby increasing the moment of inertia and moment of forgiveness.

[0107] The epoxy boundary 1146 surrounding the striking face insert 1144 may include a width. The width of the epoxy boundary 1146 can be measured as a lateral width. In many embodiments, the width of the epoxy boundary may range from 0.01 inches to 0.08 inches. In some embodiments, the width of the epoxy boundary 1146 may range from 0.01 inches to 0.04 inches, or from 0.04 inches to 0.08 inches. In some embodiments, the width of the epoxy boundary 1146 may range from 0.02 inches to 0.05 inches, 0.03 inches to 0.06 inches, 0.04 inches to 0.07 inches, or from 0.05 inches to 0.07 inches. For example, the width of the epoxy boundary may be 0.01, 0.02, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, or 0.08 inches. In one example, the width of the epoxy boundary 1146 may be 0.03 inches.

[0108] The metal portion 1142 may further include a milled pattern 1148. The milled pattern 1148 may include multiple milled lines extending vertically, horizontally, curved, arched, or circularly across the striking face. The milled pattern 1148 may extend from the crown towards the sole and / or from the heel towards the toe across the striking face. The milled pattern 1148 enhances the surface finish of the putter head or striking face and improves the appearance of the putter head.

[0109] The striking face insert systems (1120, 1130, 1140) disclosed herein can be formed by many different processes. These different forming processes include injection molding, casting, blow molding, compression molding, co-forming, laser molding, film insert molding, gas-assisted molding, rotational molding, thermoforming, laser cutting, 3-D printing, forging, stamping, electroforming, machining, molding, or any combination thereof. Furthermore, the striking face inserts can have any combination of the hardness, volume, thickness, and forming process described above.

[0110] In many embodiments, the upper part of a putter-type golf club head having the first material contains a first density in the range of 1.0 g / cc to 6.0 g / cc. The first density may be in the range of 2.0 g / cc to 5.0 g / cc. In some embodiments, the first density may be in the range of 1.0-1.25 g / cc, 1.25-1.5 g / cc, 1.5-1.75 g / cc, 1.75-2.75 g / cc, 2.0-2.25 g / cc, 2.25-2.5 g / cc, 2.5-2.75 g / cc, 2.75-3.75 g / cc, 3.25-3.5 g / cc, 3.5-3.75 g / cc, 3.75-4.0 g / cc, 4.0-4.25 g / cc, 4.5-4.75 g / cc, 4.75-5.0 g / cc, 5.0-5.25 g / cc, 5.25 g / cc-5.5 g / cc, 5.5-5.75 g / cc, or 5.75-6.0 g / cc. In one embodiment, the first density of the lower portion can be in the range of 2.0 to 3.0 g / cc. In some embodiments, the first density may be less than 6.0 g / cc, less than 5.0 g / cc, less than 4.0 g / cc, less than 3.0 g / cc, or less than 2.0 g / cc. In some embodiments, the first density may be 1.25 g / cc, 1.50 g / cc, 1.75 g / cc, 2.0 g / cc, 2.25 g / cc, 2.50 g / cc, 2.75 g / cc, 3.0 g / cc, 3.25 g / cc, 3.50 g / cc, 3.75 g / cc, 4.0 g / cc, 4.25 g / cc, 4.50 g / cc, 4.75 g / cc, 5.0 g / cc, 5.25 g / cc, 5.50 g / cc, 5.75 g / cc, or 6.0 g / cc.

[0111] In many embodiments, the lower part of the putter-type golf club head has a second material. The second material may have a density, which is the second density relative to the first density of the first material in the upper part. The second density of the second material in the lower part can be in the range of 7.0 g / cc to 20.0 g / cc. In some embodiments, the second density is 7.0-7.5 g / cc, 7.5-8.0 g / cc, 8.0-8.5 g / cc, 8.5-9.0 g / cc, 9.0-9.5 g / cc, 9.5-10.0 g / cc, 10.0-10.5 g / cc, 10.5-11.0 g / cc, 11.0-11.5 g / cc, 11.5-12.0 g / cc, 12.0-12.5 g / cc, 12.5-13.0 g / cc, 13.0-13.5 g / cc, 13.5-14.0 g / cc, 14.0-14.5 g / cc, 14.5-15.0 The density can be in the range of 0 g / cc, 16.0-16.5 g / cc, 16.5-17.0 g / cc, 17.0-17.5 g / cc, 17.5-18.0 g / cc, 18.0-18.5 g / cc, 18.5-19.0 g / cc, or 19.0-19.5 g / cc, or 19.5-20.0 g / cc. In one embodiment, the second density of the second material in the lower part can be in the range of 8.0-9.0 g / cc. In some embodiments, the second density can be 7.0 g / cc, 7.5 g / cc, 8.0 g / cc, 8.5 g / cc, 9.0 g / cc, 9.5 g / cc, 10.0 g / cc, 10.5 g / cc, 11.0 g / cc, 11.5 g / cc, 12.0 g / cc, 12.5 g / cc, 13.0 g / cc, 13.5 g / cc, 14.0 g / cc, 14.5 g / cc, 15.0 g / cc, 15.5 g / cc, 16.0 g / cc, 16.5 g / cc, 17.0 g / cc, 17.5 g / cc, 18.0 g / cc, 18.5 g / cc, 19.0 g / cc, 19.5 g / cc, or 20.0 g / cc. In some embodiments, the second density of the lower part may be at least twice, at least three times, at least four times, or at least five times the first density. In some embodiments, the second density may exceed 7.0 g / cc, exceed 9.0 g / cc, exceed 10.0 g / cc, exceed 11.0 g / cc, or exceed 12.0 g / cc.

[0112] The upper part of a putter-type golf club having the first material may be made from any or a combination of the following: 8620 alloy steel (7.83 g / cc), S25C steel (7.85 g / cc), carbon steel (7.85 g / cc), maraging steel (8.00 g / cc), 17-4 stainless steel (7.81 g / cc), 303 stainless steel (8.03 g / cc), 304 stainless steel (8.00 g / cc), stainless steel alloy (7.75 g / cc-8.05 g / cc), tungsten (19.25 g / cc), aluminum (2.70 g / cc), aluminum alloy (2.64 g / cc-2.81 g / cc), ADC-12 (2.75 g / cc), or other metal suitable for making a golf club head. In many embodiments, the upper part consists of an aluminum alloy or ADC-12.

[0113] The lower part of a putter-type golf club having a second material may be made from any or a combination of the following: 8620 alloy steel (7.83 g / cc), S25C steel (7.85 g / cc), carbon steel (7.85 g / cc), maraging steel (8.00 g / cc), 17-4 stainless steel (7.81 g / cc), 303 stainless steel (8.03 g / cc), 304 stainless steel (8.00 g / cc), stainless steel alloy (7.75 g / cc-8.05 g / cc), tungsten (19.25 g / cc), aluminum (2.70 g / cc), aluminum alloy (2.64 g / cc-2.81 g / cc), ADC-12 (2.75 g / cc), or other metals suitable for making a golf club head. In many embodiments, the lower section is made of 304 stainless steel, 8620 alloy steel, 17-4 stainless steel, or 1380 stainless steel. However, the lower and upper sections are not made from the same single material or a combination of the same materials.

[0114] Furthermore, the upper and lower parts of the putter-type golf club head can be joined by welding, soldering, brazing, swedging, adhesive bonding, epoxy, or mechanical fastening, or a combination thereof. In some embodiments, the upper and lower parts can be joined by bonding with epoxy, polyurethane, resin, hot melt, or any other adhesive.

[0115] II. Embodiment a. Blade Embodiment In one embodiment, the putter-type golf club head can be a blade-type putter head 100. Referring to Figures 1A and 1B, the blade-type putter head 100 has an upper part 104 and a lower part 108. The upper part 104 is made from a first material having a first density, and the lower part 108 is made from a second material having a second density. The first density is less than the second density. The upper part 104 and the lower part 108 are joined together to create a balanced putter head 100 while maintaining a desired volume and mass.

[0116] The lower part 108 includes a toe end 124, a heel end 128 opposite the toe end 124, a rear wall 132 opposite the front 112, a rear section 156, and a bottom surface (not shown). The bottom surface and upper part 104 form the sole 168. The rear wall 132 is opposite the front 112 and is substantially parallel to it. The toe end 124 is opposite the heel end 128 and is adjacent to the striking face 112 and the rear section 156. The rear section 156 spans from the heel end 128 to the toe end 124, while extending away from the rear wall 132 and the front face 112. The rear section 156 is adjacent to the sole. The bottom surface extends from the heel end 128 to the toe end 124 and is adjacent to the rear section 156 and the front 112.

[0117] Furthermore, the toe end 124, the heel end 128, and the front surface 112 of the lower part 108 form a recess 140, which extends inward from the front surface 112 toward the rear wall 132. The recess functions to receive the upper part 104. In most embodiments, the recess 140 has a corresponding geometric shape similar to or identical to the geometric shape of the upper part 104. Once the upper part 104 is fixed to the lower part 108, the upper part 104 surrounds and engages with the lower part 108 so as to fit within the recess 140.

[0118] The lower part 108 of the blade-type putter head 100 may further comprise an alignment mechanism 136. The alignment mechanism 136 may be one or a combination of the following: a line, a circle, a dashed line, a triangle, a groove (channel), or any other suitable alignment mechanism 136. Referring to Figures 2A to 2C, in some embodiments, the blade-type putter head 200 may have the alignment mechanism 236 on the upper part 204 rather than the lower part 208.

[0119] The upper part 104 of the blade-type putter head 100 has a striking face 113 and a bonding surface 115. The striking face 113 includes an upper edge 116 and a lower edge 121, the upper edge 116 being further from the ground plane 172 than the lower edge 121. The ground plane 172 is in contact with the lower part 108 when the putter head is in the address position to strike the golf ball. The upper edge 116 is adjacent to the striking face 113 and the bonding surface 115 and is on the opposite side from the lower edge 121. In most embodiments, the striking face 113 and the bonding surface 115 are parallel, but in other embodiments, the striking face 113 and the bonding surface 115 are not parallel.

[0120] When the upper part 104 and the lower part 108 are joined, the adhesive surface 115 is fixed to the recess 140 of the lower part 108. The striking face 113 of the upper part 104 and the front face 112 of the lower surface are aligned to form a striking face 120, which functions to strike the golf ball.

[0121] The lower edge 121 of the upper part 104 and the underside of the lower part 108 combine to form the sole 168. The sole 168 is perpendicular to the ground plane 172. The ground plane 172 is tangential to the sole 168 when the putter 100 is in the address position where it strikes the golf ball. The sole 168 of the putter 100 extends from the toe end 124 of the putter head 100 to the heel end 128 of the putter head 100.

[0122] Referring to Figure 1C, in most embodiments, the sole 168 of the putter head 100 may be perfectly flat. In some embodiments, the sole 168 of the putter head 100 may have a slight arch in the direction from heel 128 to toe 124. The slight arch may be a linear or polynomial function. In some embodiments, the sole 168 of the putter head 100 may have a strong arch in the direction from heel 128 to toe 124, and the strong arch may be a linear or polynomial function. The sole 168 functions to provide a surface for resting the putter head 100 on the ground plane 172.

[0123] The striking face 120 of the blade-type putter head 100 comprises a striking face center point 176 and a loft plane 180. The striking face center point 176 is equidistant from the lower edge 120 and upper edge 116 of the striking face 120, and similarly equidistant from the heel end 128 and toe end 124 of the blade-type putter head 100. The loft plane 180 is tangent to the striking face 112 of the blade-type putter head 100. Furthermore, the central plane 184 intersects the striking face center point 176 and is perpendicular to the loft plane 180. Furthermore, the y-axis 188 intersects the striking face center point 176 and is perpendicular to the ground plane 172.

[0124] In some embodiments, when the lower part 108 and the upper part 104 are joined, the upper edge 116 of the upper part 104 can overlap at least a portion of the rear wall 132 of the lower part 108 and project away from the striking face 120. Furthermore, the lower edge 121 of the upper part 104 can project away from the striking face 120 toward at least a portion of the underside of the lower part 108, thereby forming part of the sole 168. In these embodiments, the rear wall 132 of the lower part 108 does not form part of the sole 168.

[0125] The combination of a lower 104 made of a low-density first material and a lower 108 made of a high-density second material increases the MOI of the putter 100 compared to a putter with a single solid block structure. The two sub-components of the putter 100 (upper 104 and lower 108) increase the MOI of the putter 100 because the denser material is shifted towards the heel 128 and toe 124, while the lighter material (upper 104) is positioned near the center, thus increasing the MOI of the putter 100 as more mass is further away from the center of gravity. The denser material in the lower part helps increase the MOI of the putter-type golf club head by shifting the weight of the putter head 100 towards the outer part of the putter-type golf club head. In a single-material putter, it is not possible to allocate high-density material to the periphery. In some embodiments, a putter-type golf club head 100 having an upper 104 and lower 108 made of two different materials increases the MOI around the y-axis center of gravity by at least 15% compared to a putter with the same volume, mass, and single-material structure.

[0126] b. Embodiment of a blade with heel and toe mass In some embodiments of the present invention, the putter-type golf club head may be a blade-type putter head 1700. Referring to Figures 17A-17E, the blade-type putter head 1700 has an upper part 1704 and a lower part 1708. The upper part 1704 is made of a first material having a first density, and the lower part 1708 is made of a second material having a second density. The first density is less than the second density. The two-part blade-type putter head 1700 is formed by the upper part 1704 covering the rear end of the lower part 1708 without disturbing the striking face 1720. The upper part 1704 and the lower part 1708 combine to maintain a high moment of inertia (3500 g·cm) while maintaining a desired volume and mass. 2 ~5000g·cm 2 Create a balanced putter head 1700 with the following features.

[0127] As described above, the lower section 1708 is made of a high-density material (i.e., the second material). Referring to Figure 17A, the lower section 1708 includes a toe end 1724, a heel end 1728 opposite the toe end 1724, a front 1712 defining the striking face 1720, a rear wall 1732 opposite the front 1712, a rear section 1756, and a sole 1768. The rear wall 1732 is opposite the front 1712 and is approximately parallel to it. The toe end 1724 is opposite the heel end 1728, while being adjacent to the striking face 1720 and the rear section 1756. The rear section 1756 extends from the heel end 1728 to the toe end 1724, while also extending away from the rear wall section 1732 and the front section 1712. The rear section 1756 is adjacent to the sole 1768. The sole 1768 extends from the heel end 1728 to the toe end 1724 and is adjacent to the rear 1756 and front 1712.

[0128] In many embodiments, the sole 1768 includes a variable thickness. The sole 1768 includes a center portion 1744, a heel portion 1746, and a toe portion 1748, where the heel portion 1746 and the toe portion 1748 each include a thickness greater than that of the center portion 1744. In many embodiments, transition regions 1750 may be provided between the heel portion 1746 and the center portion 1744, and between the center portion 1744 and the toe portion 1748. The transition regions 1750 provide a gradual and smooth transition between the different thicknesses of the sole 1768. By reducing the thickness of the center portion 1744 and increasing the thickness of the heel portion 1746 and the toe portion 1748 of the sole 1768, more mass is allocated toward the periphery of the putter head 1700, and therefore the MOI increases. As will be discussed further below, the lower part 1708 may further include heel mass 1741 and toe mass 1743 to further increase the weighting around the putter head 1700 and increase the MOI.

[0129] In many embodiments, the sole 1768 of the putter head 1700 may be flat or planar. In some embodiments, the sole 1768 of the putter head 1700 may have a slight curve from the heel 1728 to the toe 1724, and the slight curve may be linear or a polynomial function. In some embodiments, the sole 1768 of the putter head 1700 may have a strong curve from the heel 1728 to the toe 1724, and the strong curve may be linear or a polynomial function. The sole 1768 functions to provide a surface for placing the putter head 1700 on the ground.

[0130] In some embodiments, referring to Figure 17B, the lower section 1708 includes an opening 1764 extending through the front section 1712 and the rear wall 1732. The opening 1764 is located in the center of the front section 1712 and is configured to receive at least a portion of the low-density upper section 1704. As shown in Figure 17B, the opening 1764 is substantially rectangular. In other embodiments, the opening 1764 may be circular, curved, triangular, trapezoidal, parabolic, golf ball-shaped, square, or any other desired shape. The opening 1764 allows mass to be removed from the center of the lower front section 1712 and redistributed to other areas of the putter head 1700 to increase perimeter weighting and provide a higher MOI.

[0131] As described above, the upper part 1704 is made of a low-density material (i.e., the first material). The upper part 1704 is configured to cover the lower part 1708 and create a putter head 1700 having a solid structure. The upper part 1704 covers the rear end of the lower part 1708. In some embodiments, as will be described in more detail below, the upper part 1704 can form part of the striking face 1720. Referring to Figure 17D, the upper part 1704 comprises a body 1790, a heel extension 1792 formed between the body 1790 and the heel-side periphery 1760, and a toe extension 1794 formed between the body 1790 and the toe-side periphery 1756. The upper section 1704 further includes a front edge 1770, a back edge 1734 opposite the front edge 1770, and a crown 1742, the crown 1742 extending over the entire length of the upper section 1704, from the front edge 1770 to the back edge 1734, and from the heel-side perimeter 1760 to the toe-side perimeter 1756.

[0132] The body 1790 is a substantially solid structure. The body 1790 has a shape configured to correspond to the shape of the lower part 1708. The body 1790 abuts against the central part 1744 of the sole 1768 and is positioned between the heel part 1746 and the toe part 1748. In many embodiments, referring to Figure 17A, the body 1790 abuts against the rear wall 1732 of the lower part 1708.

[0133] Referring here to the embodiment in Figure 17B, in some embodiments, the body 1790 includes a projection 1786 that forms the foremost part of the body 1790. As shown in Figure 17D, the projection 1786 extends from the body 1790 toward the lower front surface 1712. The projection 1786 penetrates and fills an opening 1764 formed in the front surface 1712 of the lower part 1708. The projection 1786 includes a shape that matches the shape of the opening 1764 provided in the lower front surface 1712, so that when the upper part 1704 and the lower part 1708 are joined, the body 1790 completely fills the opening 1764. As shown in Figure 17E, when joined to the lower part 1708, the front surface 1788 of the body 1790 becomes coplanar with the front surface 1712 of the lower part 1708. In this way, the lower front surface 1712 and the upper body 1790 are combined to form a continuously and firmly constructed striking face 1720. As a result, the striking face 1720 is formed as a high-density material (i.e., the second material) with an opening 1764 substantially located in the center and filled with a low-density material (i.e., the first material). The striking face 1720 includes a low-density first material near the center, surrounded toward the periphery of the striking face 1720 by a higher-density second material.

[0134] The crown 1742 of the upper 1704 forms the entire upper surface of the upper 1704. The crown 1742 extends from the front edge 1770 to the back edge 1734, and from the toe-side perimeter 1756 to the heel-side perimeter 1760, covering the entire span of the upper 1704. When joined to the lower 1708, the crown 1742 forms the majority of the upper part of the putter head 1700, although a smaller portion of the upper part of the putter head 1700 may be formed by the lower 1708. In many embodiments, the crown 1742 includes a smooth, continuous surface. In the embodiment shown in Figure 17C, the crown 1742 has a concave curve. In some embodiments, the concave curve of the crown 1742 can substantially coincide with the curve of the sole 1768. In other embodiments, the crown 1742 may be substantially flat. In yet another embodiment, the crown 1742 may not be substantially smooth and instead may include one or more surface mechanisms (not shown) that provide roughness or discontinuity to the crown 1742.

[0135] In some embodiments, the lower surface 1774 of the upper part 1704 can form a first cavity 1796. The first cavity 1796 is recessed within the lower surface of the toe extension 1794. The first cavity 1796 is recessed toward the crown 1742 but does not penetrate the crown 1742 completely. The first cavity 1796 is surrounded by the back edge 1734, the crown 1742, the front edge 1770, and the toe-side periphery 1756. The toe extension 1794 covers the toe mass 1741 of the lower part 1708, completely concealing the toe mass 1741 within the first cavity 1796.

[0136] In some embodiments, the underside of the upper portion 1704 can form a second cavity 1798. The second cavity 1798 is recessed within the underside of the heel extension 1792. The second cavity 1798 is recessed toward the crown 1742 but does not penetrate the crown 1742 completely. The second cavity 1798 is surrounded by the back edge 1734, the crown 1742, the front edge 1770, and the heel-side perimeter 1760. The heel extension 1792 covers the heel mass 1743 of the lower portion 1708, completely concealing the heel mass 1741 within the second cavity 1798.

[0137] The first and second cavities 1796, 1798 can include any desired shape. However, in most embodiments, the first and second cavities include shapes similar to or identical to the shapes of the corresponding toe mass 1741 and heel mass 1743. Furthermore, if the upper part 1704 is attached to the lower part 1708, the upper part 1704 covers the lower part 1708 such that the toe mass 1741 is housed in the first cavity 1796 and the heel mass 1743 is housed in the second cavity 1798.

[0138] The upper part 1704 and the lower part 1708 are joined together to form a putter head 1700 with a rigid structure having a high MOI. The upper part 1704 and the lower part 1708 are shaped complementaryly to fit together without any internal voids or hollow spaces. As described above, the upper part 1704 covers the lower part 1708 and fills the opening 1764 formed in the front surface 1712 of the lower part. The body 1790 of the lower part 1708 fits accordingly into the sole 1768 and protrudes through the opening 1764 to form a continuous striking face 1720. The toe extension 1794 and the heel extension 1792 cover the toe mass 1741 and the heel mass 1743, respectively.

[0139] As described above, in some embodiments, the putter head 1700 may further include a toe mass 1741 and a heel mass 1743. The weights of the heel mass 1741 and the toe mass 1743 can be adjusted to achieve a desired swing weight or overall putter head mass. Referring to Figures 17A and 17B, the toe mass 1741 and the heel mass 1743 are located in the toe portion 1748 and the heel portion 1746 of the sole 1768, respectively. The heel mass 1741 and the toe mass 1743 may be integral with the lower portion 1708 and may be formed from a second material of the lower portion 1708. In other embodiments, the toe mass 1741 and the heel mass 1743 may be formed from a third material having a third density greater than the second density of the lower portion 1708. The toe mass 1741 and the heel mass 1743 extend vertically from the lower portion 1708. The toe mass 1741 and heel mass 1743 provide means for positioning and aligning the upper part 1704 with the lower part 1708 of the putter head 1700.

[0140] Furthermore, the toe mass 1741 and heel mass 1743 provide additional means of adding mass to the periphery to increase the MOI of the blade-shaped putter head 1700 compared to a putter without such a mass mechanism. The heel mass 1741 and toe mass 1743 may contain a density greater than or equal to the second density of the rest of the lower part 1708. The toe mass 1741 and heel mass 1743 may have a mass in the range of 10 to 40 grams. In some embodiments, the toe mass 1741 and heel mass 1743 may each contain a mass of about 25 grams. In some embodiments, the toe mass 1741 and heel mass 1743 may have a mass in the range of 10 to 25 grams, 15 to 30 grams, 20 to 35 grams, or 25 to 40 grams. In some embodiments, the toe mass 1741 and heel mass 1743 can have masses in the range of 10–20 grams, 15–25 grams, 20–30 grams, 25–35 grams, or 30–40 grams. In some embodiments, the toe mass 1741 and heel mass 1743 can include masses of about 15 grams, 16 grams, 17 grams, 18 grams, 19 grams, 20 grams, 21 grams, 22 grams, 23 grams, 24 grams, 25 grams, 26 grams, 27 grams, 28 grams, 29 grams, 30 grams, 31 grams, 32 grams, 33 grams, 34 grams, or 35 grams.

[0141] The toe mass 1741 and the heel mass 1743 may each have the same mass or may include different masses within the range provided above. The toe mass 1741 and the heel mass 1743 may each be one or a combination of the following shapes: rectangle, triangle, pyramidal, sphere, crescent, square, cylindrical, oval, elliptical, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0142] Referring to Figures 17A and 17B, the toe mass 1741 and heel mass 1743 can be positioned away from one or more of the rear perimeter 1752, the toe-side perimeter 1756, and the heel-side perimeter 1760, where the toe mass 1741 and heel mass 1743 do not touch or intersect with the rear perimeter 1752, the toe-side perimeter 1756, and / or the heel-side perimeter 1760. However, in other embodiments, the toe mass 1741 and heel mass 1743 can be positioned within one or more of the rear perimeter 1752, the toe-side perimeter 1756, and the heel-side perimeter 1760, where the toe mass 1741 and heel mass 1743 are integral to and intersect with the rear perimeter 1752, the toe-side perimeter 1756, and / or the heel-side perimeter 1760.

[0143] Referring to Figures 17A and 17B, the toe mass 1741 and heel mass 1743 can be spaced rearward from the rear wall 1732, and the toe mass 1741 and heel mass 1743 do not contact or intersect with the rear wall 1732. However, in other embodiments, the toe mass 1741 and heel mass 1743 are formed integrally with the rear wall 1732, and the front portions of the heel mass 1743 and toe mass 1741 intersect with the rear wall 1732.

[0144] The toe mass 1741 and heel mass 1743 provide areas of concentrated mass so that they function to increase the moment of inertia of the putter head 1700. Placing the toe mass 1741 and heel mass 1743 on or near the front 1712 and on or near the toe-side periphery 1756 and heel-side periphery 1760, respectively, increases the MOI by shifting the mass away from the center of gravity of the putter head 1700. The toe mass 1741 and heel mass 1743 can be integrally formed from a second material, which is denser than the first material.

[0145] The toe mass 1741 and heel mass 1743 provide a dual function: as a result, they not only function to increase the MOI of the putter head 1700, but also to provide an additional surface for the upper part 1704 to bond to the lower part 1708. Thus, the toe mass 1741 may also be called the front toe bonding portion 1741, and the heel mass 1743 may also be called the front heel bonding portion 1743.

[0146] The lower part 1708 of the blade-type putter head 1700 may further include an alignment mechanism (not shown). The alignment mechanism may be one or a combination of lines, circles, dashed lines, triangles, channels, or any other desired alignment mechanism. In some embodiments, the blade-type putter head 1700 may have the alignment mechanism on the upper part 1704 instead of the lower part 1708.

[0147] The combination of a low-density first material upper 1704 and a high-density second material lower 1708 increases the MOI of the putter head 1700 through a single solid block structure putter. The two-part structure of the putter head 1700 (upper 1704 and lower 1708) increases the MOI of the putter head 1700 because more mass is further from the center of gravity, by positioning the lower-density material (upper 1704) closer to the center while shifting the higher-density material toward the heel 1728 and toe 1724. The higher-density material of the lower 1708 helps increase the MOI of the putter head 1700 by shifting the mass of the putter head 1700 toward the outer part of the putter head 1700. A single-material putter cannot allocate high-density material to the periphery while maintaining the desired volume (50cc-75cc) and mass (340g-385g). For example, the putter head 1700 has a high MOI (4187g·cm). 2), a desired volume (55 cc), and a desired mass (361 grams). In some embodiments, a putter head 1700 having an upper part 1704 and a lower part 1708 of two different materials increases the MOI around the y-axis center of gravity by at least 15% compared to a putter of the same volume, mass, and single-material construction.

[0148] In this embodiment, the lower section 1708 may comprise a larger proportion of the volume of the putter head 1700 compared to other putter head embodiments disclosed herein. In many embodiments, the lower section 1708 may comprise less than 80% of the volume of the putter head 1700. In some embodiments, it may comprise less than 79%, less than 78%, less than 77%, less than 76%, less than 75%, less than 74%, less than 73%, less than 72%, less than 71%, or less than 70% of the total volume of the putter head 1700.

[0149] Due to the high proportion of volume provided by the lower part 1708, the lower part can also comprise a sufficiently high proportion of the mass of the putter head 1700. The lower part 1708 comprises at least 85% of the total mass of the putter head 1700. In some embodiments, the lower part 1708 comprises at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, or at least 95% of the total mass of the putter head 1700.

[0150] The beneficial transfer of mass to the periphery of the putter head 1700 increases the MOI of the putter head 1700 through the use of high-density lower 1708 and heel mass 1743 and toe mass 1741. The putter head 1700 has an increased MOI compared to putters of the same volume, mass, and single-material construction (e.g., a putter milled from a single stainless steel block, or an investment-cast putter from a single material).

[0151] c. Crescent-shaped embodiment In one embodiment, the putter-type golf club head can be a crescent-shaped putter head 300. Referring to Figures 3A-3C, the crescent-shaped putter head 300 has an upper part 304 and a lower part 308. The upper part 304 is made from a first material having a first density, and the lower part 308 is made from a second material having a second density. The first density is lower than the second density. The upper part 304 and the lower part 308 combine to create a balanced putter head 300 while maintaining the desired volume and mass. The high-density lower part 308 and low-density upper part 304 place more mass near the periphery of the putter head 300. Thus, the MOI and stability are increased compared to a putter with the same volume, mass, and single-material structure.

[0152] As described above, the lower part 308 is made of a high-density material (i.e., the second material). The lower part 308 includes a rear perimeter 352, a toe end 312, a heel end 316, a striking face 320, a rear wall 332, a back edge 334, a crown 342, and a bottom surface (not shown). The bottom surface and the upper part 304 form the sole 368. The toe end 312 is opposite the heel end 316. The toe end 312 and heel end 316 of the lower part 308 include a toe-side perimeter 356 and a heel-side perimeter 360, respectively. The striking face 320 faces the rear wall 332 from the toe end 312 to the heel end 316. The rear wall 332 is opposite to the striking face 320 and is substantially parallel to it. The lower part further comprises a heel-side peripheral portion 360, a toe-side peripheral portion 356, a front edge 348, and an upper edge 312.

[0153] The front edge 348 is adjacent to the toe-side perimeter 356 and the heel-side perimeter 360, and is on the opposite side of the rear perimeter 352. The toe-side perimeter 356 is adjacent to the front edge 348 and the rear perimeter 352, and is on the opposite side of the heel-side perimeter 360. The heel-side perimeter 360 is also adjacent to the front edge 348 and the rear perimeter 352, but is on the opposite side of the toe-side perimeter 356.

[0154] In most embodiments, the toe-side perimeter 356 extends perpendicularly from the front edge 348 toward the back edge 352 such that a right angle (90°) is formed at the junction of the toe-side perimeter 356 and the front edge 348. However, in other embodiments, the toe-side perimeter 356 can extend in any direction from the front edge 348 such that any angle (0° to 180°) can be formed at the junction of the toe-side perimeter 356 and the front edge 348. Furthermore, in most embodiments, the heel-side perimeter 360 extends perpendicularly from the front edge 348 such that a right angle (90°) is formed at the junction of the heel-side perimeter 360 and the front edge 348. However, in other embodiments, the heel-side perimeter 360 can extend in any direction from the front edge 348 such that any angle (0° to 180°) can be formed at the junction of the heel-side perimeter 360 and the front edge 348.

[0155] The front edge 348, the toe-side perimeter 356, and the heel-side perimeter 360 form an opening 364. The opening 364 is bounded by the front edge 348, the toe-side perimeter 356, and the heel-side perimeter 360. The opening 364 shifts the majority of the putter's volume and mass to the end of the lower section 308. The opening 364 can include any shape, but in one embodiment, the opening 364 is substantially rectangular. In other embodiments, the opening 364 may be circular, curved, triangular, trapezoidal, parabolic, golf ball-shaped, square, or any other desired geometric shape.

[0156] The upper part 304 of the putter head 300 comprises a crown 342, a front edge 370, and a back edge 334. The crown 342 extends from the front edge 370 to the back edge 334 of the upper part 304. The underside is the opposite of the crown 342, which spans from the front edge 348 to the back edge 334.

[0157] In some embodiments, the heel-side perimeter 360 and the toe-side perimeter 356 may be parallel, but in some embodiments, the heel-side perimeter 360 and the toe-side perimeter 356 are not parallel. In some embodiments, the rear perimeter 352 and the front edge 348 may be parallel, but in some embodiments, the rear perimeter 352 and the front edge 348 are not parallel. The rear perimeter 352 of the crescent-shaped putter head 300 is substantially crescent-shaped, and therefore the rear perimeter 352 and the front edge 348 are not parallel. The rear perimeter 352 may be a curve extending from the heel-side perimeter 360 to the toe-side perimeter 356. The rear perimeter 352 includes a curved length measured along the rear perimeter 352 from the junction between the heel-side perimeter 360 and the rear perimeter 352 to the junction between the toe-side perimeter 356 and the rear perimeter 352. In some embodiments, the curve length of the rear perimeter 352 may be between 4.5 inches and 6.5 inches. In some embodiments, the curve length of the rear perimeter can be 4.5 inches to 4.75 inches, 4.75 inches to 5.0 inches, 5.0 inches to 5.25 inches, 5.25 inches to 5.5 inches, 5.5 inches to 5.75 inches, 5.75 inches to 6.0 inches, 6.0 inches to 6.25 inches, or 6.25 inches to 6.5 inches.

[0158] When the upper part 304 and the lower part 308 are joined, the crown 342 extends between the striking face 320 to the rear perimeter 352. In most embodiments, the crown 342 extends approximately 25% inside the entire width of the clubhead 300 from the toe perimeter 356 and approximately 25% inside the entire width of the clubhead 300 from the heel perimeter 360. In other embodiments, the crown 342 can extend continuously or discontinuously across the entire width of the clubhead 300, from the heel 316 towards the toe 312. In some embodiments, the crown 342 can extend less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, or less than 30% of the total width of the clubhead 300. Furthermore, in some embodiments, the crown 342 may be substantially flat from the striking face 320 to the back edge 334, or it may rise from the striking face 320 to the back edge 334. In most embodiments, the rise or fall of the crown 342 may be a function of a straight line, a curve, a parabola, a sine wave, or a polynomial.

[0159] The crown 342 further includes an alignment trough 355. The alignment trough 355 is equidistant from the heel end 316 and the toe end 312. The alignment trough 355 is adjacent to the rear wall 328 and is substantially perpendicular to the striking face. The alignment trough 355 is bounded by the back edge 334, the rear wall 332, and the crown 342 over the heel end 316 and the toe end 312. In most embodiments, the alignment trough is substantially equal to the width of the golf ball (approximately 4.27 cm) and provides the viewer with a visual alignment field that widens the width of the golf ball.

[0160] Furthermore, the upper part 304 of the putter head 300 may have one or more alignment mechanisms 344 on the crown 342. The alignment mechanisms 344 can be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 344. The alignment mechanisms 344 may be positioned at equal intervals on the entire crown 342, a portion of the crown 342, or on the alignment troughs 355. Alignment mechanisms 344 extending along the alignment troughs 355 function to provide the viewer with a visual alignment field that extends the width of the golf ball from the rear wall 332 to the back edge 334 of the putter 300. The objective is to align the entire putter 300 with the golf ball using these alignment mechanisms 344 along the crown 342 and / or the alignment troughs 355.

[0161] Referring to Figure 3C, the upper part 304 can be fixed to the lower part 308 such that the upper part 304 is further away from the ground plane than the lower part 308. Here, the ground plane 372 is in contact with the lower part 308 when the putter head 300 is in the address position to strike the golf ball.

[0162] Referring to Figure 3C, the striking face 320 of the putter head 300 includes the striking face center point 376 and the loft plane 380. The striking face center point 376 is equidistant from the underside of the crown 342 and upper part 304, and similarly equidistant from the heel end 316 and toe end 312 of the putter head 300. The loft plane 380 is tangent to the striking face 320 of the putter head 300. Furthermore, the midplane 316 intersects the striking face center point 376 and is perpendicular to the loft plane 380. Furthermore, referring to Figure 3B, the y-axis 388 intersects the midplane 384 and is perpendicular to the ground plane 372.

[0163] When the upper part 304 and the lower part 308 are joined, the heel end 316 overlaps with at least a portion of the toe-side perimeter 356. Furthermore, when the upper part 304 and the lower part 308 are joined, the toe end 312 overlaps with at least a portion of the heel-side perimeter 360. Furthermore, when the upper part 304 and the lower part 308 are joined, the striking face 320 overlaps with at least a portion of the front edge 316. Finally, the upper part 304 and the lower part 308 are joined such that the back edge 364 overlaps with at least a portion of the rear perimeter 332.

[0164] The front edge 316, rear peripheral portion 332, toe-side peripheral portion 356, and heel-side peripheral portion 360 of the lower portion 308 combine with the upper portion 304 to form the sole 368. The sole 368 is perpendicular to the ground plane 372, where the ground plane 372 is in contact with the sole 368 when the putter head 300 is in the address position to strike the golf ball. The sole 368 of the putter head 300 extends from the toe end 312 to the heel end 316.

[0165] In most embodiments, the sole 368 of the putter head 300 may be perfectly flat. In some embodiments, the sole 368 of the putter head 300 may have a slight arch in the direction from heel 324 to toe 320, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 368 of the putter head 300 may have a strong arch in the direction from heel 324 to toe 320, and the strong arch may be a linear or polynomial function. The sole 368 functions to provide a surface for resting the putter head 300 on the ground plane 372.

[0166] Referring to Figure 3A, in one embodiment, the lower part 308 may further comprise a toe mass 341 and a heel mass 343. The toe mass 341 and heel mass 343 are integral with the lower part 308 and are in contact with the toe-side peripheral portion 356 and the heel-side peripheral portion 360, respectively. The toe mass 341 and heel mass 343 extend from the lower part 308 away from the ground plane 372 and toward the upper part 304. The toe mass 341 and heel mass 343 provide means for positioning and aligning the upper part 304 with the lower part 308 of the putter head 300.

[0167] Furthermore, the toe mass 341 and heel mass 343 provide additional means of adding weight to the periphery to increase the MOI of the crescent-shaped putter head 300 compared to a putter without these mass features. These mass features can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. The mass features can all have the same weight, or they can be different weights within the above ranges. The weight of the mass features can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The toe mass 341 and heel mass 343 can each be any one or combination of the following shapes: rectangle, triangle, pyramidal, sphere, crescent, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0168] Referring to Figure 3A, the toe mass 341 and heel mass 343 can be positioned away from the rear perimeter 352. Here, the toe mass 341 and heel mass 343 do not contact or intersect with the rear perimeter 352. However, in other embodiments, the toe mass 341 and heel mass 343 can be positioned on the rear perimeter 352. In this case, the toe mass 341 and heel mass 343 are integral with and intersect with the rear perimeter 352.

[0169] In one embodiment, the toe mass 341 is positioned on the front edge 348 at the junction of the toe-side periphery 356 and the front edge 348, but in other embodiments, the toe mass 341 can be positioned at any location along the toe-side periphery 356. In one embodiment, the heel mass 343 is positioned on the front edge 348 at the junction of the heel-side periphery 360 and the front edge 348, but in other embodiments, the heel mass 343 can be positioned at any location along the heel-side periphery 360.

[0170] The toe mass 341 and heel mass 343 provide areas of concentrated mass so that they function to increase the moment of inertia of the putter head 300. Since the toe mass 341 and heel mass 343 are far from the center of gravity of the putter 300, the MOI is increased if the toe mass 341 is placed on or near the front edge 348 and on or near the toe-side perimeter 356, and the heel mass 343 is placed on or near the front edge 348 and on or near the heel-side perimeter 360, respectively. The toe mass 341 and heel mass 343 can be integrally formed from a second material, which is denser than the first material.

[0171] The toe mass 341 and heel mass 343 serve two functions, not only increasing the MOI of the putter 300 but also providing an additional surface for the upper part 304 to bond to the lower part 308. Thus, the toe mass 341 may also be called the front toe bonding portion 341, and the heel mass 343 may also be called the front heel bonding portion 343.

[0172] In some embodiments, the lower surface of the upper 304, the crown 342, the front edge 370, and the back edge 334 can form a first cavity (not shown). The first cavity extends inward from the lower surface of the toe end 312 toward the crown 342, but does not reach the crown 342. The first cavity is bounded by the back edge 334, the crown 342, and the front edge 370. The first cavity functions to receive the toe mass 341 of the lower 308.

[0173] In some embodiments, the lower surface of the upper 304, the crown 342, the front edge 370, and the back edge 334 can form a second cavity (not shown). The second cavity extends inward from the lower surface of the heel end 316 toward the crown 342, but does not reach the crown 342. The second cavity is bounded by the back edge 334, the crown 342, and the front edge 370. The second cavity functions to accommodate the heel mass 343 of the lower 308.

[0174] The first and second cavities can include any desired geometric shape. However, in most embodiments, the first and second cavities have geometric shapes similar to or identical to the geometric shape of the corresponding toe mass 341 or heel mass 343. Furthermore, when the upper part 304 is fixed to the lower part 308, the first cavity is positioned so that the first cavity surrounds the toe mass 341, and the second cavity is positioned so that the second cavity surrounds the heel mass 343.

[0175] The combination of the upper part 304 of a low-density first material and the lower part 308 of a high-density second material produces a high-MOI putter 300 without producing an extremely heavy putter. The large opening 364 formed by the rear wall 332, rear perimeter 352, toe-side perimeter 356, and heel-side perimeter 360 of the lower part 308 forms a high-density but low-volume section that can increase the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the perimeter while maintaining the desired volume (50cc to 75cc) and mass (340 grams to 385 grams).

[0176] In most embodiments, the lower part 308 constitutes less than 38% of the volume of the putter 300. In some embodiments, the lower part 308 includes less than 37%, less than 36%, less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 300.

[0177] The lower section 308 constitutes less than half the volume of the putter 300, but the lower section 308 constitutes at least 45% of the total mass of the putter 300. In some embodiments, the lower section 308 constitutes at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the total mass of the putter 300.

[0178] The beneficial shift of mass around the putter head 300 increases the MOI of the putter 300 compared to putters with the same volume, mass, and single-material construction (i.e., putter milled from a single stainless steel block, or putter investment casting from a single material).

[0179] d. Semicircular embodiment In one embodiment, the putter-type golf club head can be a semicircular putter head 400. Referring to Figures 4A-4C, the semicircular putter head 400 has an upper part 404 and a lower part 408. The upper part 404 is made from a first material having a first density, and the lower part 408 is made from a second material having a second density. The first density is less than the second density. The upper part 404 and the lower part 408 are combined to create a high MOI putter head 400 (5000 g·cm²) while maintaining the desired volume and mass. 2 -6500g·cm 2 ) generates.

[0180] As described above, the lower section 408 is made of a high-density material (i.e., the second material). The lower section 408 comprises a front edge 448, a rear perimeter 452, a toe-side span 456, and a heel-side span 460. The lower section 408 and the underside of the upper section 404 combine to form the sole 468. The front edge 448 is adjacent to the toe-side span 456 and the heel-side span 460, and opposite to the rear perimeter 452. The toe-side span 456 is adjacent to the front edge 448 and the rear perimeter 452, and opposite to the heel-side span 460. The heel-side span 460 is also adjacent to the front edge 448 and the rear perimeter 452, but opposite to the toe-side span 456. The toe-side span 456 and the heel-side span 460 extend beyond the rear perimeter 448 of the upper section 404. In some embodiments, the heel span 460 and the toe span 456 may be parallel, but in some embodiments, the heel span 460 and the toe span 456 are not parallel. In some embodiments, the rear perimeter 452 and the front edge 448 may be parallel, but in some embodiments, the rear perimeter 452 and the front edge 448 are not parallel. In this embodiment, the rear perimeter 452 is substantially semicircular, and therefore, the rear perimeter 452 and the front edge 448 are not parallel.

[0181] In most embodiments, the toe span 456 extends perpendicularly from the front edge 448 such that a right angle (90°) is formed at the junction of the toe span 456 and the front edge 448. However, in other embodiments, the toe span 456 can extend in any direction from the front edge 448 such that any angle (0° to 180°) can be formed at the junction of the toe span 456 and the front edge 448. Furthermore, in most embodiments, the heel span 460 extends perpendicularly from the front edge 448 such that a right angle (90°) is formed at the junction of the heel span 460 and the front edge 448. However, in other embodiments, the heel span 460 can extend in any direction from the front edge 448 such that any angle (0° to 180°) can be formed at the junction of the heel span 460 and the front edge 448.

[0182] The front edge 448, the toe-side span 456, and the heel-side span 460 form a gap 464. The gap 464 is bounded by the front edge 448, the toe-side span 456, and the heel-side span 460. The gap 464 formed by the front edge 448, the toe-side span 456, and the heel-side span 460 shifts the majority of the putter's volume and mass to the lower end 408. The gap 464 can include any shape, but in one embodiment, the gap is substantially rectangular. In other embodiments, the gap 464 may be circular, curved, triangular, trapezoidal, parabolic, golf ball-shaped, square, or any other desired geometric shape.

[0183] The upper part 404 of the putter head 400 comprises a toe end 412, a heel end 416, a striking face 420, a rear wall 432, a back edge 434, a crown 442, and a bottom surface (not shown). The toe end 412 is opposite the heel end 416. The striking face 420 extends from the toe end 412 to the heel end 416 and is opposite the rear wall 432. The rear wall 432 is opposite and approximately parallel to the striking face 420. The crown 442 extends away from the striking face 420 to the back edge 434 of the upper part 404. Furthermore, the bottom surface spans from the striking face 420 to the back edge 434 and is opposite to the crown 442.

[0184] The crown 442 descends further from the striking face 420 to the back edge 434. In addition, the crown 442 extends away from the striking face 420, beyond the front edge 448 of the lower part 408, to the back edge 434 of the upper part 404. In most embodiments, the crown 442 extends from the toe-side span 456 to approximately the inner 25% of the total width of the club head 400, and from the heel-side span 460 to approximately the inner 25% of the total width of the club head 400. In other embodiments, the crown 442 can extend continuously or discontinuously across the entire width of the club head 400 from heel to toe. In some embodiments, the crown 442 may extend to less than 90% of the total width of the club head 400, less than 80% of the total width of the club head 400, less than 70% of the total width of the club head 400, less than 60% of the total width of the club head 400, less than 50% of the total width of the club head 400, less than 40% of the total width of the club head 400, or less than 30% of the total width of the club head 400. Furthermore, in some embodiments, the crown 442 may be substantially flat from the striking face 420 to the back edge 434, or it may rise from the striking face 420 to the back edge 434. In most embodiments, the rise or fall of the crown 442 may be a function of a straight line, a curve, a parabola, a sine wave, or a polynomial.

[0185] The crown 442 further includes an alignment trough 455. The alignment trough 455 is equidistant from the heel end 416 and the toe end 412. The alignment trough 455 is adjacent to the rear wall 432 and is substantially perpendicular to the striking face 420. The alignment trough 455 is bounded by the crown 442 on the back edge 434, the rear wall 432, and the heel end 416, and the toe end 412. In most embodiments, the alignment trough 455 is substantially equal to the width of the golf ball (about 4.27 cm or 1.68 inches) and provides the viewer with a visual alignment field that widens the width of the golf ball.

[0186] Furthermore, the upper part 404 of the putter head 400 may have one or more alignment mechanisms 444 on the crown 442. The alignment mechanisms 444 can be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 444. The alignment mechanisms 444 may be positioned at equal intervals on the entire crown 442, a portion of the crown 442, or on the alignment troughs 455. Alignment mechanisms 444 extending along the alignment troughs 455 function to provide the viewer with a visual alignment field that extends the width of the golf ball from the rear wall 432 to the back edge 434 of the putter 400. The objective is to align the entire putter 400 with the golf ball using these alignment mechanisms 444 along the crown 442 and / or the alignment troughs 455.

[0187] Referring to Figure 4C, the upper part 404 is fixed to the lower part 408 such that the upper part 404 is further away from the ground plane 472 than the lower part 408. Here the ground plane 472 is in contact with the lower part 408 when the putter head 400 is in the address position to strike the golf ball.

[0188] Furthermore, the striking face 420 of the putter head 400 has a striking face center point 476 and a loft plane 480. The striking face center point 476 is equidistant from the underside of the crown 442 and upper part 404, and similarly equidistant from the heel end 416 and toe end 412 of the putter head 400. The loft plane 480 is tangent to the striking face 420 of the putter head 400. Furthermore, the midplane 484 intersects the striking face center point 476 and is perpendicular to the loft plane 480. Furthermore, the y-axis 488 intersects the midplane 484 and is perpendicular to the ground plane 472.

[0189] When the upper part 404 and the lower part 408 are joined, the heel end 416 overlaps with at least a portion of the toe-side span 456. Furthermore, when the upper part 404 and the lower part 408 are joined, the toe end 412 overlaps with at least a portion of the heel-side span 460. Furthermore, when the upper part 404 and the lower part 408 are joined, the striking face 420 overlaps with at least a portion of the front edge 448. Finally, the upper part 404 and the lower part 408 are joined such that the back edge 434 overlaps with at least a portion of the rear perimeter 452.

[0190] The rear perimeter 452 may be a curve extending from the heel side 416 to the toe side 416. The rear perimeter 452 includes a curve length measured along the rear perimeter 452 from the junction between the heel side 416 and the rear perimeter 452 to the junction between the toe side 416 and the rear perimeter 452. In some embodiments, the curve length of the rear perimeter 452 may range from 4.5 inches to 8.0 inches. In some embodiments, the curve length of the rear perimeter 452 may range from 4.5 inches to 4.75 inches, 4.75 inches to 5.0 inches, 5.25 inches to 5.5 inches, 5.75 inches to 6.0 inches, 6.25 inches to 6.5 inches, 6.5 inches to 6.75 inches, 6.75 inches to 7.0 inches, 7.25 inches to 7.50 inches, or 7.75 inches to 8.0 inches.

[0191] The front edge 448, rear perimeter 452, toe-side span 456, and heel-side span 460 of the lower part 408 combine with the upper part 404 to form the sole 468. The sole 468 is perpendicular to the ground plane 472, and when the putter head 400 is in the address position for striking the golf ball, the ground plane 472 is in contact with the sole 468. The sole 468 of the putter head 400 extends from the toe end 412 of the putter head 400 to the heel end 416 of the putter head 400.

[0192] In most embodiments, the sole 468 of the putter head 400 may be perfectly flat. In some embodiments, the sole 468 of the putter head 400 may have a slight arch in the direction from heel 416 to toe 412, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 468 of the putter head 400 may have a strong arch in the direction from heel 416 to toe 412, and the strong arch may be a linear or polynomial function. The sole 468 functions to provide a surface for resting the putter head 400 on the ground plane 472.

[0193] Referring to Figure 4A, in one embodiment, the lower section 408 may further comprise a front toe mass 441 and a front heel mass 443. The front toe mass 441 and front heel mass 443 are integrated into the lower section 408. The front toe mass 441 and front heel mass 443 extend from the lower section 408 away from the ground plane 472 and toward the upper section 404. These mass portions provide means for positioning and aligning the upper section 404 with the lower section 408 of the putter head 400. Furthermore, these mass portions (i.e., the front toe mass 441 and front heel mass 443) provide additional means for adding weight to the periphery to increase the MOI of the putter 400 compared to a putter without these mass portions. These mass portions may have weights in the range of 2 to 5 grams, 3 to 7 grams, or 1 to 6 grams. The mass portions may all have the same weight or may have different weights within the above ranges. The mass function may be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The front toe mass 441 and the front heel mass 443 may each be any one or combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircular, square, cylindrical, oval, elliptical, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0194] In Figure 4A, the front toe mass 441 and front heel mass 443 are positioned away from the rear perimeter 452. Here, the front toe mass 441 and front heel mass 443 do not contact or intersect with the rear perimeter 452. However, referring to Figures 5A-5C, a modified semicircular putter 500 is shown. The putter 500 has the same features as the putter 400, except that the front toe mass 541 and front heel mass 543 of the putter 500 are positioned on the rear perimeter 552. The front toe mass 541 and front heel mass 543 are integrated with and intersect with the rear perimeter 452.

[0195] In one embodiment, the front toe mass 441 is positioned on the front edge 448, which is the junction between the toe-side span 456 and the front edge 448. However, in other embodiments, the front toe mass 441 can be positioned anywhere along the toe-side span 456. In one embodiment, the front heel mass 443 is positioned on the front edge 448, which is the junction between the heel-side span 460 and the front edge 448. However, in other embodiments, the front heel mass 443 can be positioned anywhere along the heel-side span 460.

[0196] The front toe mass 441 and front heel mass 443 provide areas of concentrated mass so that each mass 441, 443 functions to increase the moment of inertia of the putter head 400. Since each mass 441, 443 is far from the center of gravity of the putter 400, placing each mass 441, 443 on the front edge 448 and spans 456, 460 increases the MOI. Each mass 441, 443 on the periphery 448 and spans 456, 460 is integrally formed from a second material, which is denser than the first material.

[0197] The front toe mass 441 and front heel mass 443 serve two functions, not only increasing the MOI of the putter 400, but also providing an additional surface for the upper part 404 to bond to the lower part 408. Thus, the front toe mass 441 may also be called the front toe bonding portion 441, and the front heel mass 443 may also be called the front heel bonding portion 443.

[0198] In some embodiments, the lower surface of the upper 404, the striking face 420, and the rear wall 432 can form a first cavity (not shown). The first cavity extends inward from the lower surface of the toe end 412 toward the crown 442, but does not reach the crown 442. The first cavity is bounded by the rear wall 432, the striking face 420, and the toe 412. The first cavity functions to receive the front toe mass 441 of the lower 408.

[0199] In some embodiments, the lower surface of the upper 404, the striking face 420, and the rear wall 432 can form a second cavity (not shown). The second cavity extends inward from the lower surface of the heel end 416 toward the crown 442, but does not reach the crown 442. The second cavity is bounded by the rear wall 432, the striking face 420, and the heel 416. The second cavity functions to receive the front heel mass 443 of the lower 408.

[0200] The first and second cavities can include any desired geometric shape, but in most embodiments, the first and second cavities include geometric shapes similar to or identical to the geometric shapes of the front toe mass 441 and the front heel mass 443. Furthermore, when the upper 704 is fixed to the lower 408, the first cavity is positioned so that the first cavity surrounds the front toe mass 441, and the second cavity is positioned so that the second cavity surrounds the front heel mass 443.

[0201] The combination of a lower 404 upper part of a low-density first material and a lower 408 lower part of a high-density second material produces a high MOI putter 400 without producing an extremely heavy putter. The large gap 464 formed by the spans 456, 460 of the rear perimeter 452 and lower 408 forms a high-density but low-volume portion that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the perimeter while maintaining the desired volume (75cc-100cc) and mass (340g-385g).

[0202] In most embodiments, the lower section 408 constitutes less than 38% of the volume of the putter 400. In some embodiments, the lower section 408 constitutes less than 37%, less than 36%, less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 400.

[0203] The lower section 408 constitutes less than half the volume of the putter 400, but the lower section 408 constitutes at least 45% of the total mass of the putter 400. In some embodiments, the lower section 408 constitutes at least 46%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the mass of the putter 400.

[0204] The beneficial shift of mass around the putter head 400 increases the MOI of the putter 400 compared to putters with the same volume, mass, and single-material construction (i.e., putters milled from a single stainless steel block, or single-material putter investment castings) through the use of a high-density, low-volume lower 408.

[0205] e. Wing-type embodiment In one embodiment, the putter-type golf club head can be a wing-shaped putter head having a peripheral span 600. Referring to Figures 6A and 6B, the wing-shaped putter head 600 has an upper part 604 and a lower part 608. The upper part 604 is made from a first material having a first density, and the lower part 608 is made from a second material having a second density. The first density is less than the second density. The upper part 604 and the lower part 608, when combined, maintain a desired volume and mass while producing a high MOI putter head 600 (5000 g·cm²). 2 -6500g·cm 2 ) generates.

[0206] As described above, the lower section 608 is made of a high-density material (i.e., a second material). The lower section 608 includes a front perimeter 648, a sole 668, a rear perimeter 652, a toe wing 656, and a heel wing 660. As will be described later, Figure 6C shows that the front perimeter 648, rear perimeter 652, toe wing 656, and heel wing 660 of the lower section 608 combine with the upper section 604 to form the sole 668. The front perimeter 648 is adjacent to the toe perimeter 656 and the heel perimeter 660, and opposite to the rear perimeter 652. The toe wing 656 is adjacent to the front perimeter 648 and the rear perimeter 652, and opposite to the heel wing 660. Furthermore, the heel wing 660 is adjacent to the front peripheral portion 648 and the rear peripheral portion 652, but opposite to the toe wing 656. The toe wing 656 and the heel wing 660 extend beyond the rear peripheral portion 648 of the upper portion 604. In some embodiments, the heel wing 660 and the toe wing 656 may be parallel, while in some embodiments, the heel wing 660 and the toe wing 656 are not parallel. In some embodiments, the rear peripheral portion 652 and the front peripheral portion 648 may be parallel, while in some embodiments, the rear peripheral portion 652 and the front peripheral portion 648 are not parallel.

[0207] In most embodiments, the toe wing 656 extends perpendicularly from the rear perimeter 652 such that a right angle (90°) is formed at the junction of the toe wing 656 and the rear perimeter 652. However, in other embodiments, the toe wing 656 can extend in any direction from the rear perimeter 652 such that any angle (0° to 180°) can be formed at the junction of the toe wing 656 and the rear perimeter 652. Furthermore, in most embodiments, the heel wing 660 extends perpendicularly from the rear perimeter 652 such that a right angle (90°) is formed at the junction of the heel wing 660 and the rear perimeter 652. However, in other embodiments, the heel wing 660 can extend in any direction from the rear perimeter 652 such that any angle (0° to 180°) can be formed at the junction of the heel wing 660 and the rear perimeter 652.

[0208] The front perimeter 648 of the lower part 608 has a front width. The front width is measured from the junction of the toe-side wing 656 and the front perimeter 648 to the junction of the heel-side wing 660 and the front perimeter 648. Furthermore, the lower part 608 has a rear width. The rear width is measured from the tip 657 of the toe-side wing 656 and the tip 661 of the heel-side wing 660. Here, tip 657 is the point of the toe-side wing 656 furthest from the front perimeter 648, and tip 661 is the point of the heel-side wing 660 furthest from the front perimeter 648. In most embodiments, the front width is greater than the rear width, but in some embodiments, the front width can be less than or equal to the rear width.

[0209] The rear perimeter 652, the toe wing 656, and the heel wing 660 form a gap 664. The gap 664 is bounded by the rear perimeter 652, the toe wing 656, and the heel wing 660. The gap 664 formed by the rear perimeter 652, the toe wing 656, and the heel wing 660 shifts most of the putter's volume and mass to the lower end 608. The gap 664 can include any shape, but in one embodiment, the gap is substantially rectangular. In other embodiments, the gap 664 may be circular, curved, triangular, trapezoidal, parabolic, golf ball-shaped, square, or any other desired geometric shape.

[0210] The upper part 604 of the putter head 600 comprises a toe end 612, a heel end 616, a striking face 620, a rear wall 632, a back edge 634, a crown 642, and a bottom surface (not shown). The toe end 612 is opposite the heel end 616. The striking face 620 extends from the toe end 612 to the heel end 616 and is opposite the rear wall 632. The rear wall 632 is opposite and approximately parallel to the striking face 620. The crown 642 extends away from the striking face 620 to the back edge 634 of the upper part 604. Furthermore, the bottom surface spans from the striking face 620 to the back edge 634 and is opposite to the crown 642.

[0211] The crown 642 further descends from the hitting face 620 to the back edge 634. Additionally, the crown 642 extends away from the hitting face 620, beyond the front perimeter 648 of the lower portion 608, to the back edge 634 of the upper portion 604. The crown 642, in most embodiments, extends to approximately the inner 25% of the full clubhead 600 width from the toe side wing 656 and to approximately the inner 25% of the full clubhead 600 width from the heel side wing 660. In other embodiments, the crown 642 can extend continuously or discontinuously across the full width of the entire clubhead 600 from heel to toe. In some embodiments, the crown 642 can extend to less than 90% of the full width of the clubhead 600, less than 90% of the full width of the clubhead 600, less than 80% of the full width of the clubhead 600, less than 70% of the full width of the clubhead 600, less than 60% of the full width of the clubhead 600, less than 50% of the full width of the clubhead 600, less than 40% of the full width of the clubhead 600, or less than 30% of the full width of the clubhead 600. Further, in some embodiments, the crown 642 can be substantially flat from the hitting face 620 to the back edge 634 or can rise from the hitting face 620 to the back edge 634. In most embodiments, the rise or fall of the crown 642 can be a linear, curved, parabolic, sine wave, or polynomial function.

[0212] The crown 642 further includes an alignment trough 655. The alignment trough 655 is equidistant from the heel end 616 and the toe end 612. The alignment trough 655 is adjacent to the rear wall 632 and is substantially perpendicular to the hitting face 620. The alignment trough 655 is bounded by the back edge 634, the rear wall 632, and the crown 642 on the heel end 616, and the toe end 612. In most embodiments, the alignment trough is approximately equal to the width of a golf ball (about 4.27 cm), providing a viewer with a visual alignment field that widens the width of the golf ball.

[0213] Furthermore, the upper portion 604 of the putter head 600 can include one or more alignment mechanisms 644 on the crown 642. The alignment mechanisms 644 can be a line, a series of lines, a milling trough, a circle, a dashed line, a triangle, a channel, or any one or combination of any other desired alignment mechanisms 644. The alignment mechanisms 644 can be equally spaced across the entire crown 642, a portion of the crown 642, or on the alignment trough 655. The alignment mechanisms 644 extending along the alignment trough 655 function to provide a viewer with a visual alignment field that extends the width of a golf ball from the rear wall 632 to the back edge 634 of the putter 600. The purpose is to align the entire putter 600 with a golf ball using these alignment mechanisms 644 along the crown 642 and / or the alignment trough 655.

[0214] The upper portion 604 is attached to the lower portion 608 such that the upper portion 604 is further away from the ground plane 672 than the lower portion 608. The ground plane 672 contacts the lower portion 608 when the putter head 600 is in the address position where it contacts a golf ball.

[0215] Furthermore, the striking face 620 of the putter head 600 includes a striking face center point 676 and a loft face 680. The striking face center point 676 is equidistant from the lower surface of the crown 642 and the upper portion 604, and similarly, is equidistant from the heel end 616 and the toe end 612 of the putter head 600. The loft face 680 is in contact with the striking face 620 of the putter head 600. Furthermore, the mid-plane 684 intersects the striking face center point 676 and is perpendicular to the loft face 680. Furthermore, the y-axis 688 intersects the mid-plane 684 and is perpendicular to the ground plane 672.

[0216] When the upper part 604 and the lower part 608 are joined, the heel end 616 overlaps with at least a portion of the toe-side wing 656. Furthermore, when the upper part 604 and the lower part 608 are joined, the toe end 612 overlaps with at least a portion of the heel-side wing 660. Furthermore, when the upper part 604 and the lower part 608 are joined, the striking face 620 overlaps with at least a portion of the front perimeter 648. Finally, the upper part 604 and the lower part 608 are joined such that the back edge 634 overlaps with at least a portion of the rear perimeter 652.

[0217] Referring to Figure 6C, the front perimeter 648, rear perimeter 652, toe wing 656, and heel wing 660 of the lower part 608 combine with the upper part 604 to form the sole 668. The sole 668 is perpendicular to the ground plane 672. The ground plane 672 is in contact with the sole 668 when the putter head 600 is in the address position to strike the golf ball. The sole 668 of the putter head 600 extends from the toe end 612 to the heel end 616.

[0218] In most embodiments, the sole 668 of the putter head 600 may be perfectly flat. In some embodiments, the sole 668 of the putter head 600 may have a slight arch in the direction from heel 616 to toe 612, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 668 of the putter head 600 may have a strong arch in the direction from heel 616 to toe 612, and the strong arch may be a linear or polynomial function. The sole 668 functions to provide a surface for resting the putter head 600 on the ground plane 672.

[0219] Referring to Figure 6A, in one embodiment, the lower part 608 may further comprise a front toe mass 641, a front heel mass 643, a toe wing mass 645, and a heel wing mass 647. The front toe mass 641, front heel mass 643, toe wing mass 645, and heel wing mass 647 are integral to the lower part 608. The front toe mass 641, front heel mass 643, toe wing mass 645, and heel wing mass 647 extend from the lower part 608 away from the ground plane 672 and toward the upper part 604. These mass portions provide means for positioning and aligning the upper part 604 with the lower part 608 of the putter head 600. Furthermore, these mass components (i.e., front toe mass 641, front heel mass 643, toe wing mass 645, and heel wing mass 647) provide an additional means of adding weight to the periphery to increase the MOI of the putter 600 compared to a putter without these mass components. These mass components can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. The mass components can all have the same weight, or they can have different weights within the above ranges. The mass components can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The front toe mass 641, front heel mass 643, toe wing mass 645, and heel wing mass 647 can each be any one or combination of rectangular, triangular, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0220] In one embodiment, the front toe mass 641 is positioned on the front peripheral portion 648 at the junction of the toe-side wing 656 and the front peripheral portion 648. However, in other embodiments, the front toe mass 641 can be positioned anywhere along the front peripheral portion 648. In one embodiment, the front heel mass 643 is positioned on the front peripheral portion 648 at the junction of the heel wing 660 and the front peripheral portion 648. However, in other embodiments, the front heel mass 643 can be positioned anywhere along the front peripheral portion 648. In one embodiment, the toe wing mass 645 can be positioned on a portion of the toe-side wing 656, but in other embodiments, the toe wing mass 645 can be positioned anywhere along a portion or all of the toe-side wing 656. In one embodiment, the heel wing mass 647 can be positioned on a portion of the heel-side wing 660, but in other embodiments, the heel wing mass 647 can be positioned along a portion or all of the heel-side wing 660.

[0221] The front toe mass 641, front heel wing mass 643, toe wing mass 645, and heel wing mass 647 provide areas of concentrated mass so that each mass 641, 643, 645, and 647 functions to increase the moment of inertia of the putter head 600. Placing each mass 641, 643, 645, and 647 on the perimeter 648 and wings 656, 660 increases the MOI because each mass 641, 643, 645, and 647 is further away from the center of gravity of the putter 600. Each mass 641, 643, 645, and 647 on the perimeter 648 and wings 656, 660 is integrally formed from a second material, which is denser than the first material.

[0222] The front toe mass 641 and front heel mass 643 serve two functions, not only increasing the MOI of the putter 600, but also providing an additional surface for the upper part 604 to bond to the lower part 608. Thus, the front toe mass 641 may also be called the front toe bonding portion 641, and the front heel mass 643 may also be called the front heel bonding portion 643.

[0223] In some embodiments, the lower surface of the upper 604, the striking face 620, and the rear wall 632 can form a first cavity (not shown). The first cavity extends inward from the lower surface above the toe end 612 toward the crown 642, but does not reach the crown 642. The first cavity is bounded by the rear wall 632, the striking face 620, and the toe 612. The first cavity functions to receive the front toe mass 641 of the lower 608.

[0224] In some embodiments, the lower surface of the upper 604, the striking face 620, and the rear wall 632 can form a second cavity (not shown). The second cavity extends inward from the lower surface above the heel end 616 toward the crown 642, but does not reach the crown 642. The second cavity is bounded by the rear wall 632, the striking face 620, and the heel 616. The second cavity functions to receive the front heel mass 643 of the lower 608.

[0225] The first and second cavities can include any desired geometric shape, but in most embodiments, the first and second cavities include geometric shapes similar to or identical to the geometric shapes of the front toe mass 641 and the front heel mass 643. Furthermore, when the upper part 604 is fixed to the lower part 608, the first cavity is positioned so that the first cavity surrounds the front toe mass 641, and the second cavity is positioned so that the second cavity surrounds the front heel mass 643.

[0226] The combination of the upper part 604 of a low-density first material and the lower part 608 of a high-density second material produces a high MOI putter 600 without producing an extremely heavy putter. The large gap 664 formed by the rear perimeter 652 and the wings 656, 660 of the lower part 608 forms a high-density but low-volume section that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the perimeter while maintaining the desired volume (75cc~100cc) and mass (340g~385g).

[0227] In most embodiments, the lower portion 608 constitutes less than 38% of the total volume of the putter 600. In some embodiments, the lower portion 608 includes less than 37%, less than 36%, less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 600.

[0228] The lower portion 608 constitutes less than half of the volume of the putter 600, but the lower portion 608 constitutes at least 45% of the total mass of the putter 600. In some embodiments, the lower portion 608 constitutes at least 46%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the total mass of the putter 600.

[0229] The beneficial shift of mass around the putter head 600 by using a high-density, low-volume lower portion 608 increases the MOI of the putter 600 more than a putter having the same volume, mass, and single-material structure (i.e., a single stainless steel block milled or a single-material investment cast putter).

[0230] f. Spade embodiments In one embodiment, the putter-type golf club head can be a spade-shaped putter head having a peripheral span 700. Referring to FIGS. 7A and 7B, the spade-shaped putter head 700 has an upper portion 704 and a lower portion 708. The upper portion 704 is made of a first material having a first density, and the lower portion 708 is made of a second material having a second density. The first density is less than the second density. The upper portion 704 and the lower portion 708 are combined to produce a high-MOI putter head 700 (5000 g·cm 2 -6500 g·cm 2 ) while maintaining the desired volume and mass.

[0231] As described above, the lower portion 708 is composed of a high-density material (i.e., the first material), thereby lowering the mass below the midline 784. The lower portion 708 includes a front peripheral portion 748, a rear peripheral portion 752, a toe-side peripheral portion 756, and a heel-side peripheral portion 760. The front peripheral portion 748 is adjacent to the toe-side peripheral portion 756 and the heel-side peripheral portion 760 and is on the opposite side of the rear peripheral portion 752. The toe-side peripheral portion 756 is adjacent to the front peripheral portion 748 and the rear peripheral portion 752 and is on the opposite side and the opposite side of the heel-side peripheral portion 760. The heel-side peripheral portion 760 is also adjacent to the front peripheral portion 748 and the rear peripheral portion 752 but is on the opposite side of the toe-side peripheral portion 756. In some embodiments, the heel-side peripheral portion 760 and the toe-side peripheral portion 756 can be parallel, but in some embodiments, the heel-side peripheral portion 760 and the toe-side peripheral portion 756 are not parallel. In some embodiments, the rear peripheral portion 752 and the front peripheral portion 748 can be parallel, but in some embodiments, the rear peripheral portion 752 and the front peripheral portion 748 are not parallel.

[0232] The front perimeter 748 of the lower part 708 has a front width. The front width is measured from the joint between the toe-side perimeter 756 and the front perimeter 748 to the joint between the heel-side perimeter 760 and the front perimeter 748. The rear perimeter 752 of the lower part 708 has a rear width. The rear width is measured from the joint between the toe-side perimeter 756 and the rear perimeter 752 to the joint between the heel-side perimeter 760 and the rear perimeter 752. In most embodiments, the front width is greater than the rear width, but in some embodiments, the front width can be less than or equal to the rear width.

[0233] The front perimeter 748, rear perimeter 752, toe-side perimeter 756, and heel-side perimeter 760 are joined together to form an opening 764. Here, the opening 764 is bounded by four perimeters (front 748, rear 752, toe-side 756, and heel-side 760). The four perimeters 756, 752, 756, and 760 form a perimeter around the opening 764. The central opening 764 formed by the perimeters 756, 752, 756, and 760 of the lower part 708 shifts most of the putter's volume and mass to the end of the lower part 708.

[0234] The upper part 704 of the putter head 700 comprises a toe end 712, a heel end 716, a striking face 720, a rear wall 732, a back edge 734, a crown 742, and a bottom surface (not shown). The toe end 712 is opposite the heel end 716. The striking face 720 extends from the toe end 712 to the heel end 716 and is opposite the rear wall 732. The rear wall 732 is opposite and is approximately parallel to the striking face 720. The crown 742 extends away from the striking face 720, covering at least a portion of the rear wall 732, to the back edge 734 of the upper part 704. Furthermore, the bottom surface is opposite the crown 742 and extends from the striking face 720 to the back edge 734.

[0235] The crown 742 further descends from the hitting face 720 to the back edge 734. Additionally, the crown 742 extends away from the hitting face 720, over at least a portion of the rear wall 732 and the opening 764 of the lower portion 708, to the back edge 734 of the upper portion 704. The crown 742, in most embodiments, extends within the inner 25% of the full clubhead 700 width from the toe side perimeter 756 and the heel side perimeter 760. In this embodiment, the crown 742 extends over approximately 50% of the width of the clubhead 700. In other embodiments, the crown 742 can extend from heel to toe across the full width of the entire clubhead 700. In some embodiments, the crown 742 can extend less than 90% of the full width of the clubhead 700, less than 90% of the full width of the clubhead 700, less than 80% of the full width of the clubhead 700, less than 70% of the full width of the clubhead 700, less than 60% of the full width of the clubhead 700, less than 50% of the full width of the clubhead 700, less than 40% of the full width of the clubhead 700, or less than 30% of the full width of the clubhead 700. Further, in some embodiments, the crown 742 can be substantially flat from the hitting face 720 to the back edge 734 or can rise from the hitting face 720 to the back edge 734. In most embodiments, the rise or fall of the crown 742 can be a linear, curved, parabolic, sine wave, or polynomial function.

[0236] Furthermore, the upper part 704 of the putter head 700 may have one or more alignment mechanisms 744 on the crown 742. The alignment mechanisms 744 can be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 744. The alignment mechanisms 744 are evenly spaced across the crown 742, and the crown is configured to be the width of a golf ball (approximately 4.27 cm). The alignment mechanisms 744 extending along the crown 742 function to provide the viewer with a visual alignment field that extends the width of a golf ball from the striking face 720 to the back edge 734 of the putter 700. The objective is to align the entire putter 700 to a golf ball using these alignment mechanisms 744 along the crown 742.

[0237] Referring to Figure 7C, the upper part 704 is fixed to the lower part 708 such that the upper part 704 is further away from the ground plane 772 than the lower part 708. Here, the ground plane 772 is in contact with the lower part 708 when the putter head 700 is in the address position to strike the golf ball.

[0238] Furthermore, the striking face 720 of the putter head 700 has a striking face center point 776 and a loft plane 780. The striking face center point 776 is equidistant from the heel end 716 and toe end 712 of the putter head 700, as well as equidistant from the underside of the crown 742 and upper part 704. The loft plane 780 is tangent to the striking face 720 of the putter head 700. Furthermore, the midplane 784 intersects the striking face center point 776 and is perpendicular to the loft plane 780. Furthermore, the y-axis 788 intersects the midplane 784 and is perpendicular to the ground plane 772.

[0239] When the upper part 704 and the lower part 708 are joined, the heel end 716 overlaps with at least a portion of the heel-side perimeter 760. Furthermore, when the upper part 704 and the lower part 708 are joined, the toe end 712 overlaps with at least a portion of the toe-side perimeter 756. Furthermore, when the upper part 704 and the lower part 708 are joined, the striking face 720 overlaps with at least a portion of the front perimeter 748. Finally, the upper part 704 and the lower part 708 are joined such that the back edge 734 overlaps with at least a portion of the rear perimeter 752.

[0240] Referring to Figure 7D, the four peripheral portions of the lower part 708 (front 748, rear 752, toe side 756, and heel side 760) combine with the upper part 704 to form the sole 768. The sole 768 is perpendicular to the ground plane 772. The ground plane 772 is in contact with the sole 768 when the putter head 700 is in the address position to strike the golf ball. The sole 768 of the putter head 700 extends from the toe end 712 to the heel end 716.

[0241] In most embodiments, the sole 768 of the putter head 700 may be perfectly flat. In some embodiments, the sole 768 of the putter head 700 may have a slight arch in the direction from heel 716 to toe 712, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 768 of the putter head 700 may have a strong arch in the direction from heel 716 to toe 712, and the strong arch may be a linear or polynomial function. The sole 768 functions to provide a surface for resting the putter head 700 on the ground plane 772.

[0242] Referring to Figure 7A, in one embodiment, the lower part 708 may further comprise a front mass 741, a rear mass 743, a toe mass 745, and a heel mass 747. The front mass 741, rear mass 743, toe mass 745, and heel mass 747 are integral to the lower part 708. The front mass 741, rear mass 743, toe mass 745, and heel mass 747 extend from the lower part 708 away from the ground plane 772 and toward the upper part 704. These mass portions provide means for positioning and aligning the upper part 704 with the lower part 708 of the putter head 700. Furthermore, these mass portions (i.e., the front mass 741, rear mass 743, toe mass 745, and heel mass 747) provide additional means for adding weight to the periphery to increase the MOI of the putter 700 compared to a putter without these mass portions. These mass features can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. All mass features can have the same weight, or they can have different weights within the above ranges. Mass features can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. Front mass 741, rear mass 743, toe mass 745, and heel mass 747 can each be any one or combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircular, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0243] In one embodiment, the front mass 741 is positioned on the front perimeter 748, equidistant from the toe-side perimeter 756 and the heel-side perimeter 760. However, in other embodiments, the front mass 741 may be positioned anywhere along the front perimeter 748. In one embodiment, the rear mass 743 is positioned on the rear perimeter 752, equidistant from the toe-side perimeter 756 and the heel-side perimeter 760. However, in other embodiments, the rear mass 743 may be positioned anywhere along the rear perimeter 752. In one embodiment, the toe mass 745 may be positioned at the junction of the toe-side perimeter 756 and the rear perimeter 752. However, in other embodiments, the toe mass 745 may be positioned anywhere along the toe-side perimeter 756. In one embodiment, the heel mass 747 may be positioned at the junction of the heel-side perimeter 760 and the rear perimeter 752. However, in other embodiments, the heel mass 747 may be positioned anywhere along the heel-side perimeter 760.

[0244] The front mass 741, rear mass 743, toe mass 745, and heel mass 747 provide areas of concentrated mass so that each mass 741, 743, 745, and 747 functions to increase the moment of inertia of the putter head 700. By positioning each mass 741, 743, 745, and 747 on each mass 748, 752, 756, and 760, the MOI is increased because each mass 741, 743, 745, and 747 is further away from the center of gravity of the putter 700. Each mass 741, 743, 745, and 747 on the periphery 748, 752, 756, and 760 is integrally formed from a second material, which is denser than the first material.

[0245] The front mass 741 and rear mass 743 provide two functionalities: not only do they increase the MOI of the putter 700, but they also function to provide an additional surface for the upper part 704 to bond to the lower part 708. Thus, the front mass 741 can also be called the front bonding part 741 and the rear mass 743.

[0246] In some embodiments, the lower surface of the upper 704, the striking face 720, and the rear wall 732 can form a first cavity (not shown). The first cavity extends inward from the lower surface toward the crown 742, but does not reach the crown 742. The first cavity is bounded by the rear wall 732 and the striking face 720. The first cavity functions to receive the front mass 741 of the lower 708.

[0247] In some embodiments, the bottom surface, back edge 734, and crown 742 form a second cavity (not shown). The second cavity extends inward from the bottom surface toward the crown 742 but does not reach the crown 742. The second cavity is bounded by the back edge 734 and the crown 742. In most embodiments, the second cavity is positioned equidistant between the toe-side perimeter 756 and the heel-side perimeter 760 when the lower part 708 is joined to the upper part 704. The second cavity functions to accommodate the rear mass 743 of the lower part 708.

[0248] The first and second cavities can include any desired geometric shape, but in most embodiments, the first and second cavities include geometric shapes similar to or identical to the geometric shapes of the front mass 741 and the rear mass 743. Furthermore, when the upper part 704 is fixed to the lower part 708, the first cavity is positioned so that the first cavity surrounds the front mass 741, and the second cavity is positioned so that the second cavity surrounds the rear mass 743.

[0249] The combination of a low-density first material upper 704 and a high-density second material lower 708 produces a high-MOI putter 700 without producing an extremely heavy putter. The large opening 764 formed by the peripheral portions 748, 752, 756, 760 of the lower 708 forms a high-density but low-volume portion that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the periphery while maintaining the desired volume (75cc to 100cc) and mass (340 grams to 385 grams).

[0250] In most embodiments, the lower section 708 constitutes less than 35% of the total volume of the putter 700. In some embodiments, the lower section 708 constitutes less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 700.

[0251] The lower section 708 constitutes less than half the volume of the putter 700, but the lower section 708 constitutes at least 45% of the total mass of the putter 700. In some embodiments, the lower section 708 constitutes at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the mass of the putter 700.

[0252] The beneficial shift of mass around the putter head 700 increases the MOI of the putter 700 compared to a putter having the same volume, mass, and single-material construction (i.e., a putter milled from a single stainless steel block, or a single-material putter investment casting) through the use of a high-density, low-volume lower 708.

[0253] g. T-shaped embodiment with peripheral span In one embodiment, the putter-type golf club head can be a T-shaped putter head having a peripheral span of 800. Referring to Figures 8A and 8B, the T-shaped putter head having a peripheral span of 800 has an upper part 804 and a lower part 808. The upper part 804 is made from a first material having a first density, and the lower part 808 is made from a second material having a second density. The first density is less than the second density. The upper part 804 and the lower part 808, when combined, maintain a desired volume and mass, resulting in a high MOI putter head 800 (5000 g·cm²). 2 -6500g·cm 2 ) generates.

[0254] As described above, the lower section 808 is composed of a high-density material (i.e., a second material) to reduce the mass below the midline 884. The lower section 808 includes a front perimeter 848, a rear perimeter 852, a toe-side perimeter 856, and a heel-side perimeter 860. The front perimeter 848 is adjacent to the toe-side perimeter 856 and the heel-side perimeter 860, and opposite to the rear perimeter 852. The toe-side perimeter 856 is adjacent to the front perimeter 848 and the rear perimeter 852, and opposite to the heel-side perimeter 860. The heel-side perimeter 860 is also adjacent to the front perimeter 848 and the rear perimeter 852, but opposite to the toe-side perimeter 856. In some embodiments, the heel-side perimeter 860 and the toe-side perimeter 856 may be parallel, but in some embodiments, the heel-side perimeter 860 and the toe-side perimeter 856 are not parallel. In some embodiments, the rear peripheral portion 852 and the front peripheral portion 848 may be parallel, but in some embodiments, the rear peripheral portion 852 and the front peripheral portion 848 may not be parallel.

[0255] The front peripheral portion 848 of the lower part 808 has a front width. The front width is measured from the joint between the toe-side peripheral portion 856 and the front peripheral portion 848 to the joint between the heel-side peripheral portion 860 and the front peripheral portion 848. The rear peripheral portion 852 of the lower part 808 has a rear width. The rear width is measured from the joint between the toe-side peripheral portion 856 and the rear peripheral portion 852 to the joint between the heel-side peripheral portion 860 and the rear peripheral portion 852. In most embodiments, the front width is greater than the rear width, but in some embodiments, the front width can be less than or equal to the rear width.

[0256] The front perimeter 848, rear perimeter 852, toe-side perimeter 856, and heel-side perimeter 860 are joined together to form an opening 864. Here, the opening 864 is bounded by four perimeters (front 856, rear 852, toe-side 856, and heel-side 860). The four perimeters 856, 852, 856, and 860 form a perimeter around the opening 864. The central opening 864, formed by the perimeters 856, 852, 856, and 860 of the lower part 808, shifts most of the putter's volume and mass to the end of the lower part 808.

[0257] In some embodiments, the opening 864 formed by the front perimeter 848, rear perimeter 852, toe-side perimeter 856, and heel-side perimeter 860 may be any one of the following shapes: rectangle, triangle, semicircle, circle (golf ball size), circle (larger than a golf ball), circle (smaller than a golf ball), square, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0258] The upper part 804 of the putter head 800 comprises a toe end 812, a heel end 816, a striking face 820, a rear wall 832, a back edge 834, a crown 842, and a bottom surface (not shown). The toe end 812 is opposite the heel end 816. The striking face 820 extends from the toe end 812 to the heel end 816 and is opposite the rear wall 832. The rear wall 832 is opposite and is approximately parallel to the striking face 820. The crown 842 extends away from the striking face 820, covering at least a portion of the rear wall 832, to the back edge 834 of the upper part 804. Furthermore, the bottom surface is opposite the crown 842 and extends from the striking face 820 to the back edge 834.

[0259] The crown 842 descends further from the striking face 820 to the back edge 834. In addition, the crown 842 extends away from the striking face 820, beyond at least a portion of the rear wall 832 and the opening 864 of the lower part 808, to the back edge 834 of the upper part 804. In most embodiments, the crown 842 extends to the inside 25% of the entire width of the club head 800 from the toe-side periphery 856 and the heel-side periphery 860. In this embodiment, the crown 842 extends to about 50% of the width of the club head 800, and thus forms a "T shape" together with the striking face. In other embodiments, the crown 842 can extend from heel to toe across the entire width of the club head 800. In some embodiments, the crown 842 can extend to less than 90% of the total width of the club head 800, less than 80% of the total width of the club head 800, less than 70% of the total width of the club head 800, less than 60% of the total width of the club head 800, less than 50% of the total width of the club head 800, less than 40% of the total width of the club head 800, or less than 30% of the total width of the club head 800. Furthermore, in some embodiments, the crown 842 can be substantially flat from the striking face 820 to the back edge 834, or it can rise from the striking face 820 to the back edge 834. In most embodiments, the rise or fall of the crown 842 can be a function of a straight line, a curve, a parabola, a sine wave, or a polynomial.

[0260] Furthermore, the upper part 804 of the putter head 800 may have one or more alignment mechanisms 844 on the crown 842. The alignment mechanisms 844 can be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 844. The alignment mechanisms 844 are evenly spaced across the crown 842, and the crown is configured to be the width of a golf ball (approximately 4.27 cm). The alignment mechanisms 844 extending along the crown 842 function to provide the viewer with a visual alignment field that extends the width of a golf ball from the striking face 820 to the back edge 834 of the putter 800. The objective is to use these alignment mechanisms 844 along the crown 842 to align the entire putter 800 with a golf ball.

[0261] Referring to Figure 8C, the upper part 804 is fixed to the lower part 808 such that the upper part 804 is further from the ground plane 872 than the lower part 808. Here, the ground plane 872 is in contact with the lower part 808 when the putter head 800 is in the address position to strike the golf ball.

[0262] Furthermore, the striking face 820 of the putter head 800 has a striking face center point 876 and a loft plane 880. The striking face center point 876 is equidistant from the underside of the crown 842 and upper part 804, and similarly equidistant from the heel end 816 and toe end 812 of the putter head 800. The loft plane 880 is tangent to the striking face 820 of the putter head 800. Furthermore, the midplane 884 intersects the striking face center point 876 and is perpendicular to the loft plane 880. Furthermore, the y-axis 888 intersects the midplane 884 and is perpendicular to the ground plane 872.

[0263] When the upper part 804 and the lower part 808 are joined, the heel end 816 overlaps with at least a portion of the toe-side perimeter 856. Furthermore, when the upper part 804 and the lower part 808 are joined, the toe end 812 overlaps with at least a portion of the heel-side perimeter 860. Furthermore, when the upper part 804 and the lower part 808 are joined, the striking face 820 overlaps with at least a portion of the front perimeter 848. Finally, the upper part 804 and the lower part 808 are joined such that the back edge 834 overlaps with at least a portion of the rear perimeter 852.

[0264] Referring to Figure 8D, the four peripheral portions of the lower part 808 (front 848, rear 852, toe side 856, and heel side 860) combine with the upper part 804 to form the sole 868. The sole 868 is perpendicular to the ground plane 872. The ground plane 872 is in contact with the sole 868 when the putter head 800 is in the address position to strike the golf ball. The sole 868 of the putter head 800 extends from the toe end 812 to the heel end 816.

[0265] In most embodiments, the sole 868 of the putter head 800 may be perfectly flat. In some embodiments, the sole 868 of the putter head 800 may have a slight arch in the direction from heel 816 to toe 812, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 868 of the putter head 800 may have a strong arch in the direction from heel 816 to toe 812, and the strong arch may be a linear or polynomial function. The sole 868 functions to provide a surface for resting the putter head 800 on the ground plane 872.

[0266] Referring to Figure 8A, in one embodiment, the lower part 808 may further comprise a front mass 841, a rear mass 843, a toe mass 845, and a heel mass 847. The front mass 841, rear mass 843, toe mass 845, and heel mass 847 are integral with the lower part 808. The front mass 841, rear mass 843, toe mass 845, and heel mass 847 extend from the lower part 808 away from the ground plane 872 and toward the upper part 804. These mass portions provide means for positioning and aligning the upper part 804 with the lower part 808 of the putter head 800. Furthermore, these mass portions (i.e., the front mass 841, rear mass 843, toe mass 845, and heel mass 847) provide additional means for adding weight to the periphery to increase the MOI of the putter 800 compared to a putter without these mass portions. These mass features can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. All mass features can have the same weight, or they can be different weights within the above ranges. Mass features can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. Front mass 841, rear mass 843, toe mass 845, and heel mass 847 can each be any one or combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircular, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0267] In one embodiment, the front mass 841 is positioned on the front perimeter 848, equidistant from the toe-side perimeter 856 and the heel-side perimeter 860. However, in other embodiments, the front mass 841 can be positioned anywhere along the front perimeter 848. In one embodiment, the rear mass 843 is positioned on the rear perimeter 852, equidistant from the toe-side perimeter 856 and the heel-side perimeter 860. However, in other embodiments, the rear mass 843 can be positioned anywhere along the rear perimeter 852. In one embodiment, the toe mass 845 can be positioned at the junction of the toe-side perimeter 856 and the rear perimeter 852. However, in other embodiments, the toe mass 845 can be positioned anywhere along the toe-side perimeter 856. In one embodiment, the heel mass 847 can be positioned at the junction of the heel-side perimeter 860 and the rear perimeter 852. However, in other embodiments, the heel mass 847 can be positioned anywhere along the heel-side perimeter 860.

[0268] The front mass 841, rear mass 843, toe mass 845, and heel mass 847 provide areas of concentrated mass so that each mass 841, 843, 845, and 847 functions to increase the moment of inertia of the putter head 800. The arrangement of each mass 841, 843, 845, and 847 on the periphery sections 848, 852, 856, and 860 increases the MOI because each mass 841, 843, 845, and 847 is farther from the center of gravity of the putter 800. Each mass 841, 843, 845, and 847 on the periphery sections 848, 852, 856, and 860 is integrally formed from a second material, which is denser than the first material.

[0269] The front mass 841 and rear mass 843 provide two functions: not only do they increase the MOI of the putter 800, but they also function to provide an additional surface for the upper part 804 to bond to the lower part 808. Thus, the front mass 841 can also be called the front bonding part 841 and the rear mass 843.

[0270] In some embodiments, the lower surface of the upper 804, the striking face 820, and the rear wall 832 can form a first cavity (not shown). The first cavity extends inward from the lower surface toward the crown 842, but does not reach the crown 842. The first cavity is bounded by the rear wall 832 and the striking face 820. The first cavity functions to receive the front mass 841 of the lower 808.

[0271] In some embodiments, the bottom surface, back edge 834, and crown 842 form a second cavity (not shown). The second cavity extends inward from the bottom surface toward the crown 842 but does not reach the crown 842. The second cavity is bounded by the back edge 834 and the crown 832. In most embodiments, the second cavity is positioned equidistant between the toe-side perimeter 856 and the heel-side perimeter 860 when the lower part 808 is joined to the upper part 804. The second cavity functions to accommodate the rear mass 843 of the lower part 808.

[0272] The first and second cavities can include any desired geometric shape, but in most embodiments, the first and second cavities include geometric shapes similar to or identical to the geometric shapes of the front mass 841 and the rear mass 843. Furthermore, when the upper 804 is fixed to the lower 808, the first cavity is positioned so that the first cavity surrounds the front mass 841, and the second cavity is positioned so that the second cavity surrounds the rear mass 843.

[0273] The combination of a lower 804 made of a low-density first material and a lower 808 made of a high-density second material produces a high-MOI putter 800 without producing an extremely heavy putter. The large opening 864 formed by the peripheral portions 848, 852, 856, 860 of the lower 808 forms a high-density but low-volume portion that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the periphery while maintaining the desired volume (75cc to 100cc) and mass (340 grams to 385 grams).

[0274] In most embodiments, the lower section 808 constitutes less than 35% of the total volume of the putter 800. In some embodiments, the lower section 908 constitutes less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 800.

[0275] The lower portion 808 constitutes less than half the volume of the putter 800, but the lower portion 808 constitutes at least 45% of the total mass of the putter 800. In some embodiments, the lower portion 808 constitutes at least 46%, at least 46%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the mass of the putter 800.

[0276] The beneficial shift of mass to the periphery of the putter head 800 increases the MOI of the putter 800 compared to putters having the same volume, mass, and single-material construction (i.e., putters milled from a single stainless steel block, or single-material putter investment castings) through the use of the high-density, low-volume lower 808.

[0277] h. Dual rail embodiment In another embodiment, the putter-type golf club head can be a dual-rail putter head 900. Referring to Figures 9A and 9B, the dual-rail putter head 900 has an upper part 904 and a lower part 908. The upper part 904 is made of a first material having a first density, and the lower part 908 is made of a second material having a second density. The first density is less than the second density. The upper part 904 and the lower part 908, when combined, maintain a desired volume and mass while producing a high MOI putter head 900 (5000 g·cm²). 2 -6500g·cm 2 ) generates.

[0278] As described above, the lower section 908 is made of a high-density material (i.e., a second material) to reduce the mass below the midline 984. The lower section 908 comprises a front perimeter 948, a rear perimeter 952, a toe-side perimeter 956, and a heel-side perimeter 960. The front perimeter 948 is adjacent to the toe-side perimeter 956 and the heel-side perimeter 960, and opposite to the rear perimeter 952. The toe-side perimeter 956 is adjacent to the front perimeter 948 and the rear perimeter 952, and opposite to the heel-side perimeter 960. The heel-side perimeter 956 is also adjacent to the front perimeter 948 and the rear perimeter 952, but opposite to the toe-side perimeter 956. In some embodiments, the heel-side perimeter 960 and the toe-side perimeter 956 may be parallel, while in some embodiments, the heel-side perimeter 960 and the toe-side perimeter 956 are not parallel. In some embodiments, the rear peripheral portion 952 and the front peripheral portion 948 may be parallel, but in some embodiments, the rear peripheral portion 952 and the front peripheral portion 948 may not be parallel.

[0279] The front peripheral portion 948 of the lower part 908 has a front width. The front width is measured from the joint between the toe-side peripheral portion 956 and the front peripheral portion 948 to the joint between the heel-side peripheral portion 960 and the front peripheral portion 948. Furthermore, the rear peripheral portion 952 of the lower part 908 has a rear width. The rear width is measured from the joint between the toe-side peripheral portion 956 and the rear peripheral portion 952 to the joint between the heel-side peripheral portion 960 and the rear peripheral portion 952. In most embodiments, the front width is greater than the rear width, but in some embodiments, the front width can be less than or equal to the rear width.

[0280] The front perimeter 948, rear perimeter 952, toe-side perimeter 956, and heel-side perimeter 960 are joined together to form an opening 964. Here, the opening 964 is bounded by four perimeters (front 948, rear 952, toe-side 956, and heel-side 960). The four perimeters 948, 952, 956, and 960 form a perimeter around the opening 964. The central opening 964 formed by the perimeters 948, 952, 956, and 960 of the lower part 908 shifts most of the putter's volume and mass to the end of the lower part 908.

[0281] In some embodiments, the opening 964 formed by the front perimeter 948, rear perimeter 952, toe-side perimeter 956, and heel-side perimeter 960 may be any one of the following shapes: rectangle, triangle, semicircle, circle (golf ball size), circle (larger than a golf ball), circle (smaller than a golf ball), square, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0282] The upper part 904 of the dual rail putter head 900 comprises a toe end 912, a heel end 916, a striking face 920, a rear wall 932, a back edge 934, a crown 942, and a bottom surface (not shown). The toe end 912 is opposite the heel end 916. The striking face 920 extends from the toe end 912 to the heel end 916 and is opposite the rear wall 932. The rear wall 932 is opposite and is approximately parallel to the striking face 920. The crown 942 extends away from the striking face 920, covering at least a portion of the rear wall 932, to the back edge 934 of the upper part 904. Furthermore, the bottom surface is opposite the crown 942 and extends from the striking face 920 to the back edge 934.

[0283] The upper crown 942 of 904 further comprises a toe-end midrail 936 and a heel-end midrail 940. In most embodiments, the toe-end midrail 936 and the heel-end midrail 940 are substantially parallel and perpendicular to the striking face 920. Furthermore, the toe-end midrail 936 and the heel-end midrail 940 do not contact the toe-side perimeter 956 or the heel-side perimeter 960. The toe-end midrail 936 and the heel-end midrail 940 are located approximately one-third of the total clubhead width inward from the outer perimeters of the toe-side perimeter 956 and the heel-side perimeter 960, respectively. However, in other embodiments, the toe-end midrail 936 and the heel-end midrail 940 may be located more than one-third of the total clubhead width inward from the outer perimeters of the toe-side perimeter and the heel-side perimeter, respectively. The toe-end midrail 936 and the heel-end midrail 940 descend from the striking face 920 to the back edge 934. In some embodiments, the toe-end midrail 936 and heel-end midrail 940 are not parallel and are not perpendicular to the striking face 920. In some embodiments, the toe-end midrail 936 and heel-end midrail 940 may be substantially flat from the striking face 920 to the back edge 934, or they may rise from the striking face 920 to the back edge 934. In most embodiments, the rise or fall of the midrails 936, 940 may be a linear, curved, parabolic, sinusoidal, or polynomial function.

[0284] Furthermore, the upper part 904 of the dual-rail putter head 900 may be equipped with one or more alignment mechanisms 944 on the toe-end mid-rail 936 and the heel-end mid-rail 940. The alignment mechanisms 944 may be any one or a combination of lines, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 944. The alignment mechanisms 944 are spaced apart on the rails 936, 940 to be the width of a golf ball (approximately 4.27 cm). The alignment mechanisms 944 extend along the rails and provide the viewer with a visual alignment field that extends from the golf ball striking face 920 to the entire putter 900. The objective is to align the entire putter 900 to the golf ball using these alignment mechanisms 944 along the toe-end mid-rail 936 and the heel-end mid-rail 940.

[0285] The upper part 904 is fixed to the lower part 908 such that the upper part 904 is further away from the ground plane 972 than the lower part 908. The ground plane 972 is in contact with the lower part 908 when the dual rail putter head 900 is in the address position to strike the golf ball.

[0286] Furthermore, the striking face 920 of the dual rail putter head 900 has a striking face center point 976 and a loft plane 980. The striking face center point 976 is equidistant from the underside of the crown 942 and upper part 904, and similarly equidistant from the heel end 916 and toe end 912 of the dual rail putter head 900. The loft plane 980 is tangent to the striking face 920 of the dual rail putter head 900. Furthermore, the midplane 984 intersects the striking face center point 976 and is perpendicular to the loft plane 980. Furthermore, the y-axis 988 intersects the midplane 984 and is perpendicular to the ground plane 972.

[0287] When the upper part 904 and the lower part 908 are joined, the heel end 916 overlaps with at least a portion of the toe-side perimeter 956. Furthermore, when the upper part 904 and the lower part 908 are joined, the toe end 912 overlaps with at least a portion of the heel-side perimeter 960. Furthermore, when the upper part 904 and the lower part 908 are joined, the striking face 920 overlaps with at least a portion of the front perimeter 948. Finally, the upper part 904 and the lower part 908 are joined such that the back edge 934 overlaps with at least a portion of the rear perimeter 952.

[0288] Referring to Figures 9C and 9D, the four peripheral portions of the lower part 908 (front 948, rear 952, toe side 956, and heel side 960) combine with the upper part 904 to form the sole 968. The sole 968 is perpendicular to the ground plane 972. The ground plane 972 is in contact with the sole 968 when the dual rail putter head 900 is in the address position to strike the golf ball. The sole 968 of the dual rail putter head 900 extends from the toe end 912 to the heel end 916.

[0289] In most embodiments, the sole 968 of the dual rail putter head 900 may be perfectly flat. In some embodiments, the sole 968 of the putter head 900 may have a slight arch in the heel-to-toe direction, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 968 of the putter head 900 may have a strong arch in the heel-to-toe direction, and the strong arch may be a linear or polynomial function. The sole 968 functions to provide a surface for resting the dual rail putter head 900 on the ground plane 972.

[0290] Referring to Figure 9A, in one embodiment, the lower part 908 may further comprise a front mass 941, a rear mass 943, a toe mass 945, and a heel mass 947. The front mass 941, rear mass 943, toe mass 945, and heel mass 947 are integral to the lower part 908. The front mass 941, rear mass 943, toe mass 945, and heel mass 947 extend from the lower part 908 away from the ground plane 972 and toward the upper part 904. These mass portions provide means for positioning and aligning the upper part with the lower part of the dual rail putter head 900. Furthermore, these mass portions (i.e., front mass 941, rear mass 943, toe mass 945, and heel mass 947) provide additional means for adding weight to the periphery to increase the MOI of the putter compared to a putter without these mass portions. These mass portions may have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. All mass functions may have the same weight or may have different weights within the above range. A mass function may be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The front mass 941, rear mass 943, toe mass 945, and heel mass 947 may each be any one or combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircle, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0291] In one embodiment, the front mass 941 is located on the front perimeter 948, equidistant from the toe-side perimeter 956 and the heel-side perimeter 960. However, in other embodiments, the front mass 941 can be located anywhere along the front perimeter 948. In one embodiment, the rear mass 943 is located on the rear perimeter 952, equidistant from the toe-side perimeter 956 and the heel-side perimeter 960. However, in other embodiments, the rear mass 943 can be located anywhere along the rear perimeter 952. In one embodiment, the toe mass 945 can be located at the junction of the toe-side perimeter 956 and the rear perimeter 952. However, in other embodiments, the toe mass 945 can be located anywhere along the toe-side perimeter 956. In one embodiment, the heel mass 947 can be located at the junction of the heel-side perimeter 960 and the rear perimeter 952. However, in other embodiments, the heel mass 947 can be located anywhere along the heel-side perimeter 960.

[0292] The front mass 941, rear mass 943, toe mass 945, and heel mass 947 provide areas of concentrated mass so that each mass 941, 943, 945, and 947 functions to increase the moment of inertia of the putter head 900. Since each mass is far from the center of gravity of the putter 900, each mass 941, 943, 945, and 947 increases the MOI by placing each mass 941, 943, 945, and 947 on the periphery portions 948, 952, 956, and 960. Each mass 941, 943, 945, and 947 on the periphery portions 948, 952, 956, and 960 is integrally formed from a second material, which is denser than the first material.

[0293] The front mass 941, rear mass 943, toe mass 945, and heel mass 947 each provide two functions, not only adjusting the MOI of the putter 900, but also providing an additional surface for the upper part 904 to bond to the lower part 908. Thus, the front mass 941 may also be called the front bonding portion 941, the rear mass 943 may also be called the rear bonding portion 943, the toe mass 945 may also be called the toe bonding portion 945, and the heel mass 947 may also be called the heel bonding portion 947.

[0294] Furthermore, the crown 942 of the upper 904 includes a toe end cap 949 and a heel end cap 951. The toe end cap 949 and the heel end cap 951 function to fit onto the toe mass 945 and the heel mass 947, respectively. The toe end cap 949 is adjacent to the toe end midrail 936 and the back edge 934. The heel end cap 951 is adjacent to the heel end midrail 940 and the back edge 934. In most embodiments, the toe end cap 949 and the heel end cap 951 have the same geometric shape, but in some embodiments, the toe end cap 949 and the heel end cap 951 may have different geometric shapes.

[0295] In most embodiments, the toe end cap 949 and heel end cap 951 of the crown 942 are larger than the toe mass 945 and heel mass 947, respectively. As a result, the toe end cap 949 and heel end cap 951 cover the toe mass 945 and heel mass 947 when the upper part 904 is fixed to the lower part 908. Furthermore, when the upper part 904 is fixed to the lower part 908, the toe end cap 949 is positioned so that it overlaps at least a portion of the toe-side perimeter 956 and the toe mass 945. Furthermore, when the upper part 904 is fixed to the lower part 908, the heel end cap 951 is positioned so that it covers at least a portion of the heel-side perimeter 960 and the heel mass 960.

[0296] In some embodiments, the lower surface of the upper 904, the striking face 920, and the rear wall 932 can form a first cavity (not shown). The first cavity extends inward from the lower surface toward the crown 942, but does not reach the crown 942. The first cavity is bounded by the rear wall 932 and the striking face 920. The first cavity functions to receive the front mass 941 of the lower 908.

[0297] In some embodiments, the bottom surface, back edge 934, and crown 942 form a second cavity (not shown). The second cavity extends inward from the bottom surface toward the crown 942 but does not reach the crown 942. The second cavity is bounded by the back edge 934, the toe cap 949, and the heel end cap 951. In most embodiments, the second cavity is equidistant from the toe end cap 949 and the heel end cap 951. The second cavity functions to accommodate the rear mass 943 of the lower 908.

[0298] The first and second cavities can include any desired geometric shape, but in most embodiments, the first and second cavities include geometric shapes similar to or identical to the geometric shapes of the front mass 941 and the rear mass 943. Furthermore, when the upper part 904 is fixed to the lower part 908, the first cavity is positioned so that the first cavity surrounds the front mass 941, and the second cavity is positioned so that the second cavity surrounds the rear mass 943.

[0299] The combination of the upper part 904 of the low-density first material and the lower part 908 of the high-density second material produces a high-MOI putter 900 without producing an extremely heavy putter. The large opening 964 formed by the peripheral parts 948, 952, 956, 960 of the lower part 908 forms a high-density but low-volume portion that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the periphery while maintaining the desired volume (75cc to 100cc) and mass (340 grams to 385 grams).

[0300] In most embodiments, the lower section 908 constitutes less than 35% of the total volume of the putter 900. In some embodiments, the lower section 908 constitutes less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, or less than 27% of the total volume of the putter 900.

[0301] The lower section 908 constitutes less than half the volume of the putter 900, but the lower section 908 constitutes at least 45% of the total mass of the putter 900. In some embodiments, the lower section 908 constitutes at least 46%, at least 46%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the mass of the putter 900.

[0302] The beneficial shift of mass to the periphery of the putter head 900 increases the MOI of the putter 900 compared to putters having the same volume, mass, and single-material construction (i.e., putters milled from a single stainless steel block, or single-material putter investment castings) through the use of a high-density, low-volume lower 908.

[0303] i. Circular Embodiment In another embodiment, the putter-type golf club head 1000 can be a circular putter head 1000. Referring to Figures 10A-10C, the circular putter head 1000 has an upper part 1004 and a lower part 1008. The lower part 1008 is made from a first material having a first density, and the upper part 1004 is made from a second material having a second density. The first density is less than the second density. The upper part 1004 and the lower part 1008, when combined, maintain a desired volume and mass, resulting in a high MOI putter head 1000 (5000 g·cm²). 2 -6500g·cm 2 ) generates.

[0304] As described above, the upper section 1004 is made of a high-density material (i.e., the second material). The upper section 1004 includes a toe end 1012, a heel end 1016, a striking face 1020, a rear wall 1032, and a bottom surface (not shown). The toe end 1012 is opposite the heel end 1016. The striking face 1020 extends from the toe end 1012 to the heel end 1016 and is opposite the rear wall 1032. The rear wall 1032 is opposite and approximately parallel to the striking face 1020.

[0305] The upper section 1004 further comprises a toe-side span 1056 and a heel-side span 1060. The toe-side span 1056 is adjacent to the toe end 1012 and opposite the heel-side span 1060. The heel-side span 1060 is also adjacent to the heel end 1016 and opposite the toe-side span 1056. In some embodiments, the heel-side span 1060 and the toe-side span 1056 may be parallel, but in some embodiments, the heel-side span 1060 and the toe-side span 1056 are not parallel. The toe-side span 1056 and the heel-side span 1060 extend away from the rear wall 1032 and the striking face 1020.

[0306] In most embodiments, the toe span 1056 extends perpendicularly from the rear wall 1032 such that a right angle (90°) is formed at the junction of the toe span 1056 and the rear wall 1032. However, in other embodiments, the toe span 1056 can extend in any direction from the rear wall 1032 such that any angle (0°-180°) can be formed at the junction of the toe span 1056 and the rear wall 1032. Furthermore, in most embodiments, the heel span 1060 extends perpendicularly from the rear wall 1032 such that a right angle (90°) is formed at the junction of the heel span 1060 and the rear wall 1032. However, in other embodiments, the heel span 1060 can extend in any direction from the rear wall 1032 so that any angle (0°-180°) can be formed at the junction of the heel span 1060 and the rear wall 1032.

[0307] The rear wall 1032, the toe span 1056, and the heel span 1060 form a gap 1064. The gap 1064 is bounded by the rear wall 1032, the toe span 1056, and the heel span 1060. The gap 1064 formed by the rear wall 1032, the toe span 1056, and the heel span 1060 moves most of the volume and mass of the putter to the end of the upper 1008. The gap 1064 can include any shape, but in one embodiment the gap is substantially rectangular. In other embodiments the gap 1064 may be circular, curved, triangular, trapezoidal, parabolic, golf ball shaped, square, or any other desired geometric shape.

[0308] The lower part 1008 of the putter head 1000 comprises a front edge 1041, a rear edge 1034, a toe edge 1043, and a heel edge 1045. The front edge 1041 is adjacent to the toe edge 1043 and the heel edge 1045, and opposite to the rear edge 1034. The toe edge 1034 is adjacent to the front edge 1041 and the rear edge 1034, and opposite to the heel edge 1045. Also, the heel edge 1045 is adjacent to the front edge 1041 and the rear edge 1034, and opposite to the toe edge 1043. In some embodiments, the toe edge 1043 and the heel edge 1045 may be parallel, but in some embodiments, the toe edge 1043 and the heel edge 1045 are not parallel. In some embodiments, the front edge 1041 and the rear edge 1034 may be parallel, but in some embodiments, the front edge 1041 and the rear edge 1034 are not parallel.

[0309] The front edge 1041, rear edge 1034, toe edge 1043, and heel edge 1045 join together to form an opening 1065. The opening 1065 is bounded by four edges (front 1041, rear 1034, toe 1043, heel 1045). The four edges 1041, 1034, 1043, and 1045 form a periphery around the opening 1065.

[0310] In some embodiments, the opening 1065 formed by the front edge 1041, rear edge 1034, toe edge 1043, and heel edge 1045 may be any one of the following shapes: rectangle, triangle, semicircle, circle (golf ball size), circle (larger than a golf ball), circle (smaller than a golf ball), square, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0311] Referring to Figure 10C, the lower part 1008 is fixed to the upper part 1004 such that the upper part 1004 and a portion of the lower part 1008 intersect with the ground plane 1072. The ground plane 1072 is in contact with the lower part 1008 when the putter head 1000 is in the address position to strike the golf ball.

[0312] Furthermore, the striking face 1020 of the putter head 1000 has a striking face center point 1076 and a loft plane 1080. The striking face center point 1076 is equidistant from the upper rail 1050 and the ground plane 1072 of the upper part 1004. The upper rail 1050 is adjacent to the striking face 1020 and the rear wall 1032, while facing the ground plane 1072. The striking face center point 1076 is also equidistant from the heel end 1016 and the toe end 1012 of the putter head 1000. The loft plane 1080 is tangent to the striking face 1020 of the putter head 1000. Furthermore, the midplane 1084 intersects with the striking face center point 1076 and is perpendicular to the loft plane 1080. Furthermore, the y-axis 1088 intersects the midplane 1084 and is perpendicular to the ground plane 1072.

[0313] When the upper 1004 and lower 1008 are joined, the toe-side span 1056 overlaps at least a portion of the toe edge 1043. Furthermore, when the upper 1004 and lower 1008 are joined, the heel-side span 1060 overlaps at least a portion of the heel edge 1045. Furthermore, when the upper 1004 and lower 1008 are joined, the striking face 1020 overlaps at least a portion of the front edge 1048. Finally, when the upper 1004 and lower 1008 are joined so that the lower 1008 is fixed to the striking face 1020, the toe-side span 1056, and a portion of the heel-side span 1060, at least a portion of the gap 1064 formed by the rear wall 1032, the toe-side span 1056, and the heel-side span 1060 is filled.

[0314] Referring to Figure 10D, the sole 1068 is formed when the lower part 1008 is combined with the toe-side span 1056 and heel-side span 1060 of the upper part 1004. The sole 1068 is perpendicular to the ground plane 1072, which is in contact with the sole 1068 when the putter head 1000 is in the address position to strike the golf ball. The sole 1068 of the putter head 1000 extends from the toe end 1012 to the heel end 1016.

[0315] In most embodiments, the sole 1068 of the putter head 1000 may be perfectly flat. In some embodiments, the sole 1068 of the putter head 1000 may have a slight arch in the direction from heel 1016 to toe 1012, and the slight arch may be a linear or polynomial function. In some embodiments, the sole 1068 of the putter head 1000 may have a strong arch in the direction from heel 1016 to toe 1012, and the strong arch may be a linear or polynomial function. The sole 1068 functions to provide a surface for resting the putter head 1000 on the ground plane 1072.

[0316] In some embodiments, the upper part 1004 may further comprise a crown (not shown). The crown extends from the striking face 1020 to the back edge 1034 of the lower part 1008. Furthermore, the crown extends from the striking face 1020 to the back edge 1034, covering at least a portion of the lower opening 1065 and at least a portion of the rear wall 1032.

[0317] The crown can extend further down from the striking face 1020 to the back edge 1034. In most embodiments, the crown extends from the toe span 1056 to approximately 25% of the total width of the clubhead 1000, and from the heel span 1060 to approximately 25% of the total width of the clubhead 1000. In other embodiments, the crown can extend continuously or discontinuously across the entire width of the clubhead 1000 from heel to toe. In some embodiments, the crown can extend to less than 90% of the total width of the clubhead 1000, less than 80% of the total width of the clubhead 1000, less than 70% of the total width of the clubhead 1000, less than 60% of the total width of the clubhead 1000, less than 50% of the total width of the clubhead 1000, less than 40% of the total width of the clubhead 1000, or less than 30% of the total width of the clubhead 1000. Furthermore, in some embodiments, the crown can be substantially flat from the striking face 1020 to the back edge 1034, or it can rise from the striking face 1020 to the back edge 1034. In most embodiments, the rise or fall of the crown can be a linear, curved, parabolic, sinusoidal, or polynomial function.

[0318] Furthermore, the upper part 1004 of the putter head 1000 may be equipped with one or more alignment mechanisms 1044 on the toe span 1065 and heel span 1060. The alignment mechanisms 1044 can be any one or a combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanisms 1044. The alignment mechanisms 1044 may be evenly spaced along the entire toe span 1065 and heel span 1060, a portion of the crown, or the entire crown. Alignment mechanisms 1044 extending along the toe span 1056 and heel span 1060 serve to provide the viewer with a visual alignment field extending the width of a golf ball from the rear wall 1032 to the back edge 1034 of the putter 1000. The objective is to align the entire putter 1000 with the golf ball using these alignment mechanisms 1044 along the toe span 1056 and the heel span 1060 and / or the crown.

[0319] The combination of a high-density first material upper section 1004 and a low-density second material lower section 1008 produces a high-MOI putter 1000 without producing an extremely heavy putter. The large gap 1064 formed by the spans 1056, 1060 of the rear wall 1032 and upper section 1004 forms a high-density but low-width perimeter that increases the MOI of the putter (compared to a putter milled from a single material). A single-material putter cannot allocate high-density material to the perimeter while maintaining the desired volume (75cc-100cc) and mass (340g-385g).

[0320] The beneficial shift of mass around the putter head 1000 due to the use of a high-density upper 1004 and a low-volume, low-mass lower 1008 increases the MOI of the putter 1000 compared to a putter having the same volume, mass, and single-material construction (i.e., a putter milled from a single stainless steel block, or a single-material putter investment casting).

[0321] III. Embodiment of the Sole Plate The following describes an additional multi-component putter head embodiment including an upper and lower section. The lower section further includes a sole plate formed from a high-density material, while the upper section is formed from a low-density material. The material density of the upper section is lower than that of the lower section including the sole plate. The sole plate embodiment described below includes a mass structure, a ball retrieval mechanism, and / or a ball outline alignment aid, providing a more consistent and forgiving putt. As described below, the putter head including the upper section and the lower section including the sole plate is visually pleasing while increasing perimeter weighting, MOI, and forgiveness to create a consistent putting stroke. The putter head including the upper section and the lower section including the sole plate also provides consistent ball velocity and ball travel distance for repeated putts.

[0322] a. A putter head equipped with a sole plate having heel and toe mass. In another embodiment, the putter-type golf club head may be a semicircular putter head 1200 including a sole plate. Referring to Figures 12A to 12E, the semicircular putter head 1200 has an upper part 1204 and a lower part 1208. The upper part 1204 is formed from a first material having a first density, and the lower part 1208 is made from a second material having a second density. The first density is less than the second density. The sole plate of the putter head 1200 increases the perimeter weighting and MOI. The upper part 1204 and the lower part 1208 work together to create a high MOI putter head 1200 (3000 g·cm²) while maintaining the desired volume and mass. 2 ~4000g·cm 2 ) to create. For example, putter head 1200 is 3000g·cm 2 ~3500g·cm 2 Or 3500g·cm 2 ~4000g·cm 2The MOI can be in the range of . The putter head 1200 includes a 2% to 15% increase in MOI around the y-axis compared to a putter head lacking a multi-material structure (i.e., a single material). For example, the putter head 1200 includes increases of 2% to 5%, 5% to 10%, or 10% to 15% compared to a single-material putter.

[0323] As described above, the putter head 1200 may include a striking face mechanism 1100, as shown in Figures 11A to 11C. The putter head 1200 may include a striking face insert formed from a single-component system 1120 or a two-component system 1130. The putter head 1200 may include a striking face insert positioned between one or more metal parts 1142. The striking face mechanism 1100 can improve the sound and feel during impact with the striking face of the putter head 1200.

[0324] The lower section 1208 contains a high-density material (i.e., a second material) to reduce its mass below the midline 1284. The lower section 1208 further includes a sole plate formed from the high-density material. As shown in Figure 12C, the lower section 1208 includes a front perimeter 1248, a rear perimeter 1252, a toe perimeter 1256, and a heel perimeter 1260. The front perimeter 1248 is adjacent to the toe perimeter 1256 and the heel perimeter 1260, and opposite to the rear perimeter 1252. The toe perimeter 1256 is adjacent to the front perimeter 1248 and the rear perimeter 1252, and opposite to the heel perimeter 1260. The heel perimeter 1260 is also adjacent to the front perimeter 1248 and the rear perimeter 1252, but opposite to the toe perimeter 1256. In many embodiments, as shown in Figure 12B, the heel-side perimeter 1260 and the toe-side perimeter 1256 may be symmetrical with respect to a horizontal centerline extending through the center point 1276 of the striking face in the direction extending from the striking face 1220 to the back edge 1234. The horizontal centerline extends parallel to the ground plane 1272. In many embodiments, the heel-side perimeter 1260 and the toe-side perimeter 1256 may include similar curved edges or follow similar curved paths around the perimeter of the putter head 1200.

[0325] The front perimeter 1248 of the lower section 1208 includes a front width. The front width is measured from the junction of the toe-side perimeter 1256 and the front perimeter 1248 to the junction of the heel-side perimeter 1260 and the front perimeter 1248. The rear perimeter 1252 of the lower section 1208 also has a rear width. The rear width is measured from the junction of the toe-side perimeter 1256 and the rear perimeter 1252 to the junction of the heel-side perimeter 1260 and the rear perimeter 1252. In many embodiments, the front width is greater than the rear width, but in some embodiments, the front width may be less than or equal to the rear width.

[0326] The upper part 1204 of the putter head 1200 includes a toe end 1212, a heel end 1216, a striking face 1220, a back edge 1234, a crown 1242, and a bottom surface 1290 (shown in Figure 12D). The toe end 1212 is opposite the heel end 1216. The striking face 1220 extends from the toe end 1212 to the heel end 1216. The crown 1242 extends the entire width of the striking face 1220 from the toe end 1212 toward the heel end 1216. The crown 1242 extends between the striking face 1220 and the back edge 1234 of the upper part 1204. Furthermore, the bottom surface 1290 is opposite the crown 1242 and extends from the striking face 1220 to the back edge 1234.

[0327] The crown 1242 further descends from the striking face 1220 to the back edge 1234. Furthermore, the crown 1242 extends away from the striking face 1220, across most of the lower portion 1208, to the back edge 1234 of the upper portion 1204. In most embodiments, the crown 1242 extends across the entire width of the putter head 1200 from the toe-side perimeter 1256 and the heel-side perimeter 1260 in the heel-toe direction. Furthermore, in some embodiments, the crown 1242 can be substantially flat from the striking face 1220 to the back edge 1234, or it can rise from the striking face 1220 to the back edge 1234. In many embodiments, the descent of the crown 1242 toward the back edge 1234 can be a function of a linear, curved, parabolic, sinusoidal, or polynomial curve.

[0328] Furthermore, the upper part 1204 of the putter head 1200 may have one or more alignment mechanisms 1244 on the crown 1242. The alignment mechanisms 1244 may be any one or a combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanism 1244. The alignment mechanisms 1244 are evenly spaced across the crown 1242, and the crown is configured to be the width of a golf ball (approximately 4.27 cm). The alignment mechanisms 1244 extending along the crown 1242 function to provide the viewer with a visual alignment field that extends the width of a golf ball from the striking face 1220 to the back edge 1234 of the putter head 1200. The objective is to use these alignment mechanisms 1244 along the crown 1242 to align the putter head 1200 with a golf ball.

[0329] Referring to Figure 12D, the upper part 1204 is attached to the lower part 1208 such that the upper part 1204 is further away from the ground plane 1272 than the lower part 1208, and the ground plane 1272 is in contact with the lower part 1204 when the putter head 1200 is in the address position to strike the golf ball.

[0330] Furthermore, the striking face 1220 of the putter head 1200 includes a striking face center point 1276 and a loft plane 1280. The striking face center point 1276 is equidistant from the underside of the crown 1242 and the upper part 1204, and is also equidistant from the heel end 1216 and the toe end 1212 of the putter head 1200. The loft plane 1280 is tangent to the striking face 1220 of the putter head 1200. Furthermore, the central plane 1284 intersects the striking face center point 1276 and is perpendicular to the loft plane 1280. Furthermore, the y-axis 1288 intersects the central plane 1284 and is perpendicular to the ground plane 1272.

[0331] When the upper part 1204 and the lower part 1208 are joined, the heel end 1216 covers at least a portion of the heel-side perimeter 1260. Also, when the upper part 1204 and the lower part 1208 are joined, the toe end 1212 covers at least a portion of the toe-side perimeter 1256. Furthermore, when the upper part 1204 and the lower part 1208 are joined, the striking face 1220 covers at least a portion of the front perimeter 1248. Finally, when the upper part 1204 and the lower part 1208 are joined, the back edge 1234 covers at least a portion of the rear perimeter 1252.

[0332] The four perimeters of the lower part 1208 (front 1248, rear 1252, toe side 1256, and heel side 1260) combine with the upper part 1204 to form the sole 1268. The sole 1268 can extend nearly parallel to the ground plane 1272, and when the putter head 1200 is in the address position to strike the golf ball, the ground plane 1272 is in contact with the sole 1268. The sole 1268 of the putter head 1200 extends from the toe end 1212 to the heel end 1216 of the putter head 1200.

[0333] In most embodiments, the sole 1268 of the putter head 1200 can be flat. In some embodiments, the sole 1268 of the putter head 1200 can have a slight curve from heel 1216 to toe 1212, and the slight curve may be linear or a polynomial function. In some embodiments, the sole 1268 of the putter head 1200 can have a strong curve from heel 1216 to toe 1212, and the strong curve may be linear or a polynomial function. The sole 1268 functions to provide a surface for placing the putter head 1200 on the ground plane 1272.

[0334] Referring to Figure 12C, the lower section 1208 may further include a toe mass 1245 and a heel mass 1247. The toe mass 1245 and heel mass 1247 are integral to the lower section 1208. The toe mass 1245 and heel mass 1247 extend from the lower section 1208 toward the upper section 1204 in a direction away from the ground plane 1272. These mass portions provide means for positioning and aligning the upper section 1204 with the lower section 1208 of the putter head 1200. Furthermore, these mass mechanisms (i.e., the toe mass 1245 and the heel mass 1247) provide additional means for adding weight around the periphery of the putter head 1200. Increasing the periphery weighting may increase the moment of inertia (i.e., MOI) of the putter head 1200 compared to a putter without or lacking these mass mechanisms. Furthermore, the heel mass 1247 and toe mass 1245 weights can be adjusted to achieve the desired swing weight or overall putter head mass. These mass mechanisms can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. The toe mass 1245 and heel mass 1247 can have similar weights or include different weights within the ranges provided above. The mass mechanisms can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The toe mass 1245 and heel mass 1247 can each be one or a combination of any of the following desired geometric or non-geometric shapes: rectangle, triangle, pyramidal, spherical, semicircular, square, cylindrical, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0335] In one embodiment, the toe mass 1245 can be located at the junction of the toe-side perimeter 1256 and the rear perimeter 1252, but in other embodiments, the toe mass 1245 can be located anywhere along the toe-side perimeter 1256. In many embodiments, the toe mass 1245 can be located closer to the front perimeter 1248 than to the rear perimeter 1252. In one embodiment, the heel mass 1247 can be located at the junction of the heel-side perimeter 1260 and the rear perimeter 1252, but in other embodiments, the heel mass 1247 can be located anywhere along the heel-side perimeter 1260. In many embodiments, the heel mass 1247 can be located closer to the front perimeter 1248 than to the rear perimeter 1252.

[0336] The toe mass 1245 and heel mass 1247 provide areas of concentrated mass so that each mass 1245 and 1247 functions to increase the moment of inertia of the putter head 1200. Since each mass 1245 and 1247 is positioned away from the center of gravity of the putter head 1200, the MOI is increased by positioning each mass 1245 and 1247 on the periphery portions 1256 and 1260, respectively. Each mass 1245 and 1247 on the periphery portions 1256 and 1260 is integrally formed from a second material, which is denser than the first material.

[0337] In many embodiments, the upper 1204 can form at least one cavity. At least one cavity is formed on the lower surface 1290 of the upper 1204. As shown in Figure 12D, the upper 1204 can form a first cavity 1292 and a second cavity 1294. The first cavity 1292 and the second cavity 1294 extend inward from the lower surface 1290 of the upper 1204 toward the crown 1242, but extend through the crown 1242. The first cavity 1292 is located near the toe-side perimeter 1256 when the lower 1208 is joined to the upper 1204, and the second cavity 1294 is located near the heel-side perimeter 1260. The first cavity 1292 functions to receive the toe mass 1245 of the lower 1208. The second cavity 1294 functions to accommodate the heel mass 1247 of the lower 1208.

[0338] The first cavity 1292 and the second cavity 1294 can include any desired shape, but in most embodiments, the first cavity 1292 and the second cavity 1294 include shapes similar to or identical to the shapes of the toe mass 1245 and the heel mass 1247. In one embodiment, the first cavity 1292 and the second cavity 1294, as well as the respective toe mass 1245 and heel mass 1247, can include a general triangular shape. Furthermore, when the upper part 1204 is attached to the lower part 1208, the first cavity 1292 is positioned so that it encloses the toe mass 1245, and the second cavity 1294 is positioned so that it encloses the heel mass 1260.

[0339] The combination of an upper part 1204 containing a low-density first material and a lower part 1208 containing a high-density second material provides a high MOI putter head 1200. The putter head 1200 contains high MOI while maintaining an acceptable weight (i.e., does not create an extremely heavy putter). A single-material putter cannot allocate high-density material to the periphery while maintaining the desired volume. The putter head 1200 contains high MOI, a desired volume (75cc to 110cc), and a desired mass (340 grams to 385 grams). In one example, the putter head has a high MOI (3134 g·cm³). 2 It includes a desired volume (103 cc) and a desired mass (357 grams).

[0340] In most embodiments, the lower section 1208 includes less than 25% of the total volume of the putter head 1200. In some embodiments, the lower section 1208 includes less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, or less than 17% of the total volume of the putter head 1200. In one example, the lower section 1208 may include 16% of the total volume of the putter head 1200.

[0341] The lower part 1208 comprises less than half the volume of the putter head 1200, but the lower part 1208 includes at least 45% of the total mass of the putter head 1200. In some embodiments, the lower part 1208 includes at least 46%, at least 46%, at least 46%, at least 47%, at least 48%, at least 49%, at least 50%, at least 51%, at least 52%, at least 53%, at least 54%, or at least 55% of the mass of the putter head 1200. In one example, the lower part 1208 contains 60% of the mass of the putter head 1200.

[0342] The putter head 1200, including a high-density lower section, shifts the mass towards the periphery of the putter head 1200. This periphery weighting increases the MOI of the putter head 1200. The putter head 1200 has a larger MOI compared to a putter formed from a single-material structure with similar volume and mass (i.e., a putter milled from a single stainless steel block, or a putter skin casting from a single material).

[0343] b. Putter head with pocket and sole plate In another embodiment, as shown in Figures 13A to 13E, the putter-type golf club head may comprise a putter head 1300 having a pocket and a sole plate. As will be described in more detail below, the pocket of the putter head 1300 allows for the removal of weight from the putter head 1300, and the sole plate allows for increased perimeter weighting. The putter head 1300 comprises an upper part 1304 and a lower part 1308. The upper part 1304 is formed from a first material having a first density, and the lower part 1308 is formed from a second material having a second density. The first density is less than the second density. The upper part 1304 and the lower part 1308 combine to form a high MOI putter head (4000 g·cm²) while maintaining the desired volume and mass. 2 ~5500g·cm 2 ) is created. For example, a putter head 1300 has a weight of 4000 g·cm. 2 ~4500g·cm 2 , 4500g·cm 2 ~5000g·cm 2 , or 5000g·cm 2 ~5500g·cm 2 The MOI can be in the range of . The putter head 1300 includes a 2% to 15% increase in MOI around the y-axis compared to a putter head lacking a multi-material structure (i.e., a single material). For example, the putter head 1300 includes an increase of 2% to 5%, 5% to 10%, or 10% to 15% compared to a single-material putter.

[0344] The putter head 1300 comprises a toe end 1312, a heel end 1316, a striking face 1320, a rear end 1334, a crown 1336, and a sole 1368. The toe end 1312 is opposite the heel end 1316. The striking face 1320 extends from the heel end 1312 to the heel end 1314 in a heel-to-toe direction. The rear end 1334 is opposite the striking face 1320 and is located at the rearmost part of the putter head 1300. The crown 1336 extends away from the striking face 1320 toward the rear end 1334.

[0345] The upper section 1304 comprises a low-density material (i.e., a second material). The second material of the upper section 1304 has a lower density than the first material of the lower section 1308. The upper section 1304 includes a striking face 1320, a rear end 1334, a crown 1336, and a bottom surface 1342. The bottom surface 1342 may be the lowest surface of the upper section 1304 (i.e., the surface closest to the ground when the putter head 1300 is assembled and in the address position). The bottom surface 1342 of the upper section 1304 is configured to be attached to the lower section 1308 via adhesive.

[0346] The upper section 1304 further comprises a crown bridge 1338 extending between the striking face 1320 and the rear end 1334. The crown bridge 1338 includes a crown 1336. The upper section 1304 further comprises an upright member 1340 extending substantially perpendicularly from the crown bridge 1338. The upright member 1340 can structurally support the crown bridge 1338 and provide additional structural support to the upper section 1304.

[0347] To further remove mass from the upper part 1304, the upper part 1304 defines a pocket 1372. Specifically, as shown in Figures 13B, 13D, and 13E, the upper part 1304 comprises a front pocket wall 1376 opposite the striking face 1320, a rear pocket wall 1380 opposite the rear end 1334, a pocket ceiling 1384 opposite the crown 1384, and a pocket floor 1388 opposite the bottom surface 1342 of the upper part 1304. The front pocket wall 1376, rear pocket wall 1380, pocket ceiling 1384, and pocket floor 1388 together define a pocket 1372. The pocket 1372 of the upper part 1304 allows weight to be removed from the central part of the putter head 1300, thereby allowing weight to be reassigned to the periphery of the putter head 1300. Increasing the weighting around the perimeter increases the MOI of the 1300 putter head, resulting in greater forgiveness.

[0348] The crown bridge 1338 extends from the striking face 1320 to the rear end 1334, beyond the front pocket wall 1376. An upright member 1340 extending from the crown bridge 1338 divides the pocket 1372 into a toe pocket 1392 and a heel pocket 1396. The toe pocket 1392 and heel pocket 1396 allow weight to be removed from the upper part 1304 and reallocated to the lower part 1308, the toe mass 1345, and / or the heel mass 1347.

[0349] As shown in Figures 13A and 13B, the upper part 1304 of the putter head 1300 may have one or more alignment mechanisms 1344 positioned on the crown 1336. The alignment mechanisms 1344 may be any one or a combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment mechanism 1344. The alignment mechanisms 1344 are positioned at equal intervals on the crown 1336, and the crown 1336 is configured to be the width of a golf ball (approximately 4.27 cm or 1.68 inches). The alignment mechanisms 1344 extending along the crown 1336 function to provide the viewer with a visual alignment field that extends the width of a golf ball from the striking face 1320 to the rear end 1334 of the putter 1300. The objective is to use these alignment mechanisms 1344 along the crown 1342 to align the putter 1300 with the golf ball at the address position on the putting surface.

[0350] The upper part 1304 is attached to the lower part 1308 such that the upper part 1304 is further from the ground than the lower part 1308. The upper part 1304 can be attached to the lower part 1308 via adhesive. In other embodiments, the upper part 1304 can be attached to the lower part 1308 via a combination of adhesive and an interlock shape (e.g., a cavity that accepts a projection). The upper part 1304 is attached to the lower part 1308 such that the crown bridge 1340 is positioned between the toe mass 1345 and the heel mass 1347.

[0351] Furthermore, pocket 1372 can be positioned between the toe mass 1345 and the heel mass 1347. Specifically, as shown in Figure 13A, the toe-side pocket 1392 can be positioned between the toe mass 1345 and the upright member 1340, and the heel-side pocket 1396 can be positioned between the heel mass 1347 and the upright member 1340. Pocket 1372 removes weight from the upper part 1304 (i.e., the central part of the upper part 1304) and allows the weight to be reassigned to the lower part 1304, the toe mass 1345, and / or the heel mass 1347. The combination of the weight removal mechanism and the perimeter mass mechanism increases the MOI of the putter head 1300. The assembled putter head 1300 allows the toe mass 1345 and heel mass 1347 to be positioned around the putter head 1300. The toe mass 1345 and heel mass 1347 increase the periphery weighting of the putter head 1300, thereby increasing MOI and forgiveness. Furthermore, the weights of the heel mass 1347 and toe mass 1345 can be adjusted to achieve the desired swing weight or overall putter head mass.

[0352] When the upper part 1304 and the lower part 1308 are joined, the upper part 1304 can cover the front perimeter 1348 of the lower part 1308. When the upper part 1304 and the lower part 1308 are joined, the upper part 1304 can cover the rear perimeter 1352 of the lower part 1308. In addition, the upper part 1304 and the lower part 1308 are joined such that the rear end 1334 covers a portion of the rear perimeter 1352 of the lower part 1308. Furthermore, when the upper part 1304 and the lower part 1308 are joined, they together form the sole 1368. The sole 1368 of the putter head 1300 sits on the ground or ground plane when the putter head 1300 is in the address position.

[0353] The lower section 1308 further includes a sole plate containing a high-density material (i.e., the first material), thereby bringing the mass closer to the ground. As shown in Figures 13B and 13C, the lower section 1308 includes an outer perimeter having a front perimeter 1348, a rear perimeter 1352, a toe-side perimeter 1356, and a heel-side perimeter 1360. The front perimeter 1348 is located near or adjacent to the striking face 1320. The rear perimeter 1352 is located near or adjacent to the rear end 1334. The toe-side perimeter 1356 forms part of the toe end 1312, and the heel-side perimeter 1360 forms part of the heel end 1314.

[0354] Referring to Figures 13A and 13B, the lower section 1308 may further include a toe mass 1345 and a heel mass 1347. The toe mass 1345 and heel mass 1347 are integrated with the lower section 1308. The toe mass 1345 is located at the toe-side periphery 1356 of the lower section 1308, and the heel mass 1347 is located at the heel-side periphery 1360 of the lower section 1308. Both the toe mass 1345 and heel mass 1347 extend from the lower section 1308 away from the ground or upward from the lower section 1308. Furthermore, the toe mass 1345 and heel mass 1347 provide an additional means of adding weight around the putter head 1300. The increase in weight around the putter head 1300 increases the MOI of the putter 1300. The toe mass 1345 and heel mass 1347 can have weights in the range of 2–5 grams, 3–7 grams, or 1–6 grams. The mass mechanism can have the same weight or different weights within the above ranges. The mass mechanism can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The toe mass 1345 and heel mass 1347 can each be one or a combination of the following shapes: rectangle, triangle, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0355] The toe mass 1345 and heel mass 1347 provide areas of concentrated mass so that each mass 1345 and 1347 functions to increase the moment of inertia of the putter head 1300. Placing the toe mass 1345 on the toe periphery 1356 and the heel mass on the heel periphery 1360 increases the MOI of the putter head 1300 because the masses 1345 and 1347 are positioned around the putter head 1300 at the maximum distance from the center of gravity of the putter head 1300. Each mass 1345 and 1347 is integrally formed with a second material, the second material being denser than the first material.

[0356] The combination of an upper section 1304 containing a low-density first material and a lower section 1308 containing a high-density second material forms a high-MOI putter 1300. The putter head 1300 contains a high MOI while maintaining an acceptable weight (i.e., does not create an extremely heavy putter). The pocket 1372 formed by the pocket wall of the upper section 1304 increases the MOI of the putter 1300 by removing weight from the central part of the putter 1300. The lower section 1308, containing a high-density second material, toe mass 1345, and heel mass 1347, increases the MOI of the putter 1300 by increasing the weighting around the periphery of the putter 1300. The multi-component design of the putter 1300 provides an increased MOI compared to a putter milled from a single material. A putter formed from a single material cannot allocate high-density material to the periphery while maintaining the desired volume (75cc-100cc) and mass (340g-385g).

[0357] The lower part 1308 comprises less than 35% of the total volume of the putter 1300. In other embodiments, the lower part 1308 comprises less than 34% of the total volume of the putter 1300, less than 33% of the total volume of the putter 700, less than 32% of the total volume of the putter 1300, less than 31% of the total volume of the putter 1300, less than 30% of the total volume of the putter 1300, less than 29% of the total volume of the putter 1300, less than 28% of the total volume of the putter 1300, or less than 27% of the total volume of the putter 1300.

[0358] The lower part 1308 contains less than half the volume of the putter 1300, but the lower part 1308 contains at least 45% of the total mass of the putter 1300. In some embodiments, the lower part 1308 contains at least 46% of the mass of the putter 700, at least 47% of the mass of the putter 700, at least 48% of the mass of the putter 1300, at least 49% of the mass of the putter 1300, at least 50% of the mass of the putter 1300, at least 51% of the mass of the putter 1300, at least 52% of the mass of the putter 1300, at least 53% of the mass of the putter 1300, at least 54% of the mass of the putter 1300, or at least 55% of the mass of the putter 1300.

[0359] The putter head 1300, which includes a high-density lower section 1308, shifts the mass towards the periphery of the putter head 1300. This periphery weighting increases the MOI of the putter head 1300. The putter head 1300 has a larger MOI compared to a putter formed from a single-material structure with similar volume and mass (i.e., a putter milled from a single stainless steel block, or a putter skin casting from a single material). The advantages of the putter head 1300 over a putter head formed from a single-material structure are illustrated in the following example.

[0360] c. Putter head with sole plate and ball retrieval mechanism In another embodiment, the putter head 1400 may be a mallet-type putter head. Referring to Figures 14A to 14D, the putter head 1400 comprises an upper part 1404 and a lower part 1408. The lower part 1408 is a sole plate including a toe mass 1446, a heel mass 1448, and a rear mass 1450. The putter head 1400 further comprises a ball retrieval mechanism 1422. The ball retrieval mechanism 1422 is configured to pick up and hold a golf ball. The ball retrieval mechanism and sole plate increase the perimeter weighting, thereby increasing the MOI and forgiveness of the putter head 1400. The putter head 1400 has a weight of 4000 g·cm 2 ~5000g·cm 2It can have an MOI in the range of 400 g·cm. For example, a putter head 1400 has an MOI of 400 g·cm. 2 ~4500g·cm 2 Or 4500g·cm 2 ~5000g·cm 2 The MOI can have a range of MOI. The putter head 1400 includes a 2% to 15% increase in MOI around the y-axis compared to a putter head without a multi-material structure (i.e., single material). For example, the putter head 1400 includes increases of 2% to 5%, 5% to 10%, or 10% to 15% compared to a single-material putter.

[0361] The upper part 1404 comprises a low-density material (i.e., the first material). The upper part 1404 includes a toe end 1412, a heel end 1416, and a striking face 1420. The putter head 1400 may further include a striking face mechanism from the putter head 1100, as described above. In this embodiment, the striking face 1420 is an insert that is formed separately and then attached to the putter head 1400. In other embodiments, the striking face 1420 may be formed by the upper part 1404.

[0362] The upper section 1404 further includes an alignment mechanism 1446. The alignment mechanism is located on the crown 1444 of the putter head. In this embodiment, the alignment mechanism is defined by three lines extending perpendicularly backward from the striking face. In other embodiments, the alignment mechanism can take on various shapes and sizes according to aspects of the invention.

[0363] The lower section 1408 comprises a high-density material (i.e., a second material). The lower section 1408 is a sole plate, thereby forming the sole 1442 of the putter head 1400. The lower section 1408 includes a toe-side perimeter 1438, a heel-side perimeter 1440, a front perimeter 1434, a rear perimeter 1436, a toe mass 1446, a heel mass 1448, and a rear mass 1450. The toe mass 1446 and heel mass 1448 improve the overall MOI of the putter head. Furthermore, the weights of the heel mass 1448 and toe mass 1446 can be adjusted to achieve a desired swing weight or overall putter head mass. In this embodiment, the lower section 1408 comprises less than 37% of the total volume of the putter head 1400. In other embodiments, the lower part 1408 may contain less than 35%, 34%, 33%, 32%, 31%, 30%, 29%, or 28% of the total volume of the putter head 1400. The lower part 1408 may contain less than 37% of the total volume of the putter head 1400, but the lower part 1408 contains at least 63% of the total mass of the putter head 1400. In other embodiments, the lower part 1408 contains at least 50%, 55%, 58%, 60%, 62%, 65%, 68%, or 70% of the total mass of the putter head 1400.

[0364] The upper 1404 and lower 1408 are joined and fixed together via adhesive layers placed on the interlocking shapes of their respective parts. The upper 1404 and lower 1408 can also be joined via other fastening means known in the art. For example, the upper 1404 and lower 1408 can be joined via screws and threads, tape, or welding.

[0365] The putter head 1400 further comprises a ball retrieval mechanism 1422. The ball retrieval mechanism 1422 is located in the sole 1442 of the putter head 1400. In this embodiment, the ball retrieval mechanism 1422 is defined by a concave shape formed in the sole 1442. In other embodiments, the ball retrieval mechanism 1422 can be defined by a cavity or opening. The ball retrieval mechanism 1422 increases the MOI of the putter head by removing material and mass from the central region of the putter head, so that the majority of the mass is distributed around the periphery of the putter head 1400. The ball retrieval mechanism 1422 improves the MOI in a periphery-weighted mallet-type putter head, while incorporating a ball retrieval mechanism to provide a forgiving putter head that makes it easier to retrieve the golf ball from the putting surface during a round of golf. The advantages of the putter head 1400 over a putter head formed from a single material structure are illustrated in the following example.

[0366] In this embodiment, the ball retrieval mechanism 1422 is formed by an upper part 1404 and a lower part 1408, so that the upper part 1404 has a recess that forms part of the ball retrieval mechanism 1422 and the lower part 1408 has an opening that forms the rest of the ball retrieval mechanism 1422. In other embodiments, the ball retrieval mechanism 1422 can be formed by the upper part 1404 alone or by the lower part 1408 alone. In this embodiment, the upper part 1404 and the lower part 1408 have complementary shapes such that when placed together, the upper part 1404 and the lower part 1408 form the ball retrieval mechanism 1422.

[0367] The ball retrieval mechanism 1422 includes a ball holding section 1424. The ball holding section 1424 is configured to receive and hold a golf ball. The ball holding section 1424 is defined by a circular shape having a diameter smaller than the diameter of the golf ball (i.e., the diameter of the golf ball is approximately 1.6 inches). The diameter of the ball holding section 1424 may range from 1.45 inches to 1.75 inches to accommodate golf balls of different sizes. To properly hold the golf ball, the ball holding section 1424 includes a ball holding edge 1428. The ball holding edge 1428 is configured to grip the surface of the golf ball. Thus, the ball holding edge 1428 engages with approximately 75% to 90% of the circumference of the golf ball. In other embodiments, a ball removal edge 1430 engages with 5% to 90% of the circumference of the golf ball.

[0368] The ball retrieval mechanism 1422 further comprises a ball removal section 1426. The ball removal section 1426 is defined by a semicircular slot shape and is configured to receive the user's fingers, reach under the golf ball, and remove the ball from the ball holding section 1424. The semicircular slot shape can have a width ranging from 0.25 inches to 1 inch. The ball removal section 1426 includes a ball removal edge 1430 that does not engage with or contact the ball while the ball is received in the ball holding section 1424. The ball removal edge 1430 is offset from the ball holding edge 1428, allowing the user to reach around the golf ball. The ball removal section 1426 allows the user to grasp the periphery and underside of the golf ball (i.e., pull the golf ball out of the ball holding section and rotate it) and remove it from the putter head 1400. Pulling and rotating the golf ball from the putter head 1400 (i.e., moving it 2 degrees) is more advantageous than using pulling force (i.e., moving it 1 degree).

[0369] Figures 14E-14H show additional embodiments of the ball retrieval mechanism used in the putter head 1400. Figure 14E shows a ball retrieval mechanism 1460 comprising a ball holding section 1462, a ball removal section 1464, and a plurality of prongs 1461. In this embodiment, the ball retrieval mechanism 1460 has two prongs 1461. Each prong 1461 is positioned on the opposite side of the ball retrieval mechanism 1460. In this embodiment, one prong 1461 is positioned close to the striking face, and the other prong 1461 is positioned near the rear. The prongs 1461 define the ball holding section 1462 and the ball holding edge 1466 that engage with the ball. The ball removal section 1464 has a ball removal edge 1468 positioned adjacent to the prongs 1461. As described above, the ball removal edge 1468 does not engage with the ball.

[0370] Figure 14F shows a ball retrieval mechanism 1470 comprising a ball holding section 1472, a ball retrieval section 1474, and a plurality of prongs 1471. In this embodiment, the ball retrieval mechanism 1470 has four prongs 1471. The prongs 1471 are grouped into a first set and a second set. The first set of two prongs 1471 is positioned close to the striking face, and the second set of prongs 1471 is positioned near the rear. The prongs 1471 include a ball holding edge 1432. The ball holding edge 1432 is defined by a circle having the diameter of a golf ball. The ball retrieval section 1474 has a ball retrieval edge 1478 positioned adjacent to the prongs 1471. As described above, the ball retrieval edge 1478 does not engage with the ball.

[0371] Figure 14G shows a ball retrieval mechanism 1480 including a ball holding section 1482, a ball retrieval section 1484, and a plurality of prongs 1481. The ball holding section 1482 is defined by a circle with a diameter slightly smaller than a golf ball, as described above. In this embodiment, the ball holding section 1482 has four prongs 1481 arranged around the periphery of the circle. The prongs 1481 are spaced 90 degrees apart around the circle. The prongs 1481 further define a ball holding edge 1486. ​​The ball holding edge 1486 is curved for the circle that defines the ball holding section. The ball retrieval section 1484 is defined by a circle larger than the ball holding section 1482. The ball retrieval section 1484 is further defined by a first recess having a first depth, and the ball holding section 1482 is further defined by a second recess having a second depth such that the first depth is smaller than the second depth. The ball removal section 1484 has a ball removal edge 1488 positioned adjacent to the prong 1481. As described above, the ball removal edge 1488 does not engage with the ball.

[0372] Figure 14H shows a ball retrieval mechanism 1490 comprising a ball holding section 1492 and a ball removal section 1494. The ball retrieval mechanism 1490 has a pear shape, with the ball holding section 1492 located at the larger end of the pear shape and the ball removal section 1494 located at the smaller end of the pear shape. The ball holding section 1492 is defined by a circular shape having a diameter slightly smaller than that of a golf ball. The ball removal section 1494 is defined by a circle having a diameter smaller than that of the ball holding section 1492. The positioning and sizing of the ball holding section 1492 and the ball removal section 1494 form the pear shape. The pear shape can also be described as an ellipse. As described above, the ball holding section 1492 includes a ball holding edge 1496, and the ball removal section 1494 includes a ball removal edge 1498. As described above, the ball removal edge 1498 does not engage with the ball.

[0373] d. Putter head with ball outline alignment aid and sole plate In one embodiment, the putter-type golf club head includes a two-part structure and an alignment aid having a ball outline mechanism. The two-part structure allows the putter-type club head to be formed from multiple materials. Referring to Figures 15A and 15B, the putter-type golf club head 1500 comprises an upper part 1504 and a lower part 1508. The upper part 1504 is attached to the lower part 1508. The upper part 1504 is formed from a first material having a first density, and the lower part 1508 is formed from a second material having a second density. In some embodiments, the first density is less than the second density. As will be described in more detail below, the upper part 1504 and the lower part 1508 can be combined to create a high MOI putter-type club head 1500 (5000 g·cm²) while maintaining a desired volume and mass. 2 ~6500g·cm 2 ) is created. For example, a putter head 1500 is 5000g·cm 2 ~5500g·cm 2 5500g·cm 2 ~6000g·cm 2 6000g·cm 2 ~6500g·cm 2 The MOI can have a range of MOI. The putter head 1500 includes a 2% to 15% increase in MOI around the y-axis compared to a putter head lacking a multi-material structure (i.e., a single material). For example, the putter head 1500 includes increases of 2% to 5%, 5% to 10%, or 10% to 15% compared to a single-material putter.

[0374] The putter-type club head 1500 further comprises a crown 1536, a sole 1568, a striking face 1520, a rear end 1534, a toe end 1512, and a heel end 1516. The outermost points of the striking face 1520, the rear end 1534, the toe end 1512, and the heel end 1516 define the perimeter 1510 of the putter-type club head 1500. The upper part 1504 and the lower part 1508 are attached together and each forms part of the crown 1536, part of the sole 1568, part of the toe end 1512, part of the heel end 1516, and part of the perimeter 1510, respectively. The crown 1536 gradually slopes from the striking face 1520 to the rear end 1534, resulting in the putter-type club head 1500 being thicker near the striking face 1520 and gradually thinning towards the rear end 1534. The slope of the crown 1536 can be a linear, curved, parabolic, sinusoidal, or polynomial function. Furthermore, the striking face 1520 includes a striking face center point that is equidistant from the heel end 1516 and the toe end 1512, and equidistant from the crown 1536 and the sole 1568.

[0375] In many embodiments, the sole 1568 may be planar. In some embodiments, the sole 1568 may have a slight curve from the heel end 1516 to the toe end 1512, and the slight curve may be linear or a polynomial function. In some embodiments, the sole 1568 may have a strong curve from the heel end 1516 to the toe end 1512, and the strong curve may be linear or a polynomial function. The sole 1568 functions to provide a surface for placing the putter-type club head 1500 on the ground plane 1590. As described above, the putter-type club head 1500 includes an upper part 1504 and a lower part 1508, the lower part 1508 forming the majority of the sole 1568 and resting on the ground plane. The upper part 1504 is positioned above the lower part 1508 when assembling the putter-type club head 1500.

[0376] As described above, the upper 1504 comprises a low-density material (i.e., the first material). In many embodiments, the upper 1504 is formed from aluminum. The upper 1504 is attached to the lower 1508 to define the crown 1536, sole 1568, toe end 1512, heel end 1516, and perimeter 1510. The upper 1504 includes an upper top surface 1526 and an upper bottom surface 1528, the upper top surface 1526 forming part of the crown 1536, and the upper bottom surface 1528 forming part of the sole 1568. The upper 1504 further comprises a front portion 1522 and a rear extension 1524. The front portion 1522 includes the striking face 1520. The rear extension 1524 extends rearward from the front portion 1522 toward the rear end 1534. The rear extension 1524 is substantially perpendicular to the striking face 1520 such that the front portion 1522 and the rear extension 1524 form a T-shape.

[0377] The front portion 1522 includes a rear wall opposite the striking face 1520 near the heel end 1516 and the toe end 1512. The rear extension 1524 includes side walls near the heel end 1516 and the toe end 1512. The rear wall and side wall near the toe end 1512 define the toe wall 1529, and the rear wall and side wall near the heel end 1516 define the heel wall 1530. The toe wall 1529 and the heel wall 1530 border the T-shape of the upper 1504. Furthermore, the toe and heel walls 1529, 1530 define a notch area that allows the upper 1504 to receive the lower 1508. The notch area extends inward from the toe end 1512 or the heel end 1516 toward the center of the upper 1504. The cutout region is defined by the crown 1536, the perimeter 1510, and either the toe wall 1529 or the heel wall 1530. The toe and heel walls 1529 and 1530 define the boundary between the cutout region and the front portion 1522, as well as the boundary between the cutout region and the rear extension 1524. The cutout portion removes mass from the low-density upper portion 1504 and replaces it with the high-density lower portion 1508, increasing the perimeter weight of the putter-type club head 1500.

[0378] To further reduce the mass of the upper section 1504, the upper section 1504 defines a central recess 1570 extending from the front section 1522 to the rear section 1536. The central recess 1570 removes mass from the central section of the upper section 1504, thereby allowing the mass to move toward the periphery section 1510. The central recess 1570 is defined by a recess wall 1572 and a recess floor 1574. The recess floor 1574 is recessed within the upper section 1504, away from the upper surface 1526 of the upper section, and the recess wall 1572 is circumscribing the recess floor 1574. The recess wall 1572 defines the transition between the upper surface 1526 of the upper section and the recess floor 1574.

[0379] The recessed wall 1572 includes height. In some embodiments, the recessed wall height slopes with the inclination of the crown 1536, resulting in the recessed wall height being greater near the striking face 1520 and smaller near the rear end 1534. In such embodiments, the recessed wall 1572 has a height near the rear end 1534 such that the recessed floor 1574 is not coplanar with the upper surface 1526. In other embodiments, the recessed wall height remains constant throughout the central recess 1570. The recessed floor 1574 is parallel to the ground plane and provides a surface parallel to the ground plane to a portion of the alignment aid 1544. The central recess 1570 is located near the center of the putter-type club head 1500 within the front portion 1522 and the rear extension 1524 and provides the central mechanism of the alignment aid 1544. The central recess 1570 further contributes to the alignment aid 1544, as will be described in more detail below.

[0380] Referring to Figures 15D-15F, the upper section 1504 further comprises an alignment aid 1544. The alignment aid 1544 extends along the upper section 1504 from the front section 1522 to the rear section 1534. The alignment aid 1544, in conjunction with the central recess 1570, comprises several mechanisms that function to provide the viewer with a visual alignment field extending from the striking face 1520 to the rear section 1534. The objective is to use the alignment aid 1544 to align the entire putter-type club head 1500 with the golf ball.

[0381] The alignment aid 1544 includes several corresponding mechanisms carefully positioned relative to the central recess 1570. Referring to Figures 15D–15F, the alignment aid 1544 comprises a ball shaping mechanism 1580, a centerline 1576, and several grooves 1578. The ball shaping mechanism 1580 is formed integrally with the upper part 1504. The ball shaping mechanism 1580 is located at the center of the striking face center point and offset from the striking face 1520. The ball shaping mechanism 1580 is approximately the same width as the golf ball (1.68 inches) to help rim the golf ball during the swing. In some embodiments, the ball shaping mechanism 1580 is slightly wider than the golf ball to allow for forgiveness when rimming the ball. The ball shaping mechanism 1580 is generally a golf ball molded near the striking face 1520.

[0382] The ball shaping mechanism 1580 is located on the upper surface 1526 above the central recess 1570. However, the ball shaping mechanism 1580 generally follows the periphery of the central recess 1570. The ball shaping mechanism 1580 includes one or more curved sections 1582 and a pair of parallel lines 1584 connected to one or more curved sections 1582. At least one curved section 1582 curves near the striking face 1520 and is offset from the striking face 1520. Referring to Figure 15D, in some embodiments, the ball shaping mechanism 1580 includes two curved sections 1582, one curved near the striking face 1520 and the other curved near the rear end 1534. One or more curved sections 1582 generally resemble the halves of a golf ball. The parallel line 1584 extends rearward from the curved section 1582 toward the rear end 1534. The parallel line 1584 is generally parallel to the rear extension 1524. The parallel line 1584 is approximately equal to the width of a golf ball (1.68 inches). The ball outline mechanism 1580 is generally the width of a golf ball and generally resembles an elongated golf ball to help the viewer visualize the trajectory of the golf ball. The ball outline mechanism is located on the upper surface 1526 and outlines the central recess 1570.

[0383] The ball outline mechanism 1580 partially or completely circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 connect multiple arcuate sections 1582, as shown in Figure 15D, to form a circular or rectangular ball outline mechanism 1580 that completely encloses the central recess 1570. In other embodiments having only one arcuate section 1582, the parallel lines 1584 extend rearward, thereby defining a U-shaped ball outline mechanism 1580 that partially circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 extend completely to the rear end 1534, as shown in Figure 15E. In other embodiments, the parallel lines 1584 extend partially to the rear end 1534, as shown in Figure 15F. The ball outline mechanism 1580 is generally positioned on the upper surface 1526, following the perimeter of the central recess 1570.

[0384] In some embodiments, the ball outline mechanism 1580 is recessed in the upper part 1504, away from the upper surface 1526, thereby defining a channel. However, in other embodiments, the ball outline mechanism 1580 is coplanar with the upper surface 1526. Furthermore, in other embodiments, the ball outline mechanism 1580 protrudes from the upper surface 1526. The ball outline mechanism 1580 is located on the upper surface 1526 outside the central recess 1570. The alignment aid 1544 further comprises a centerline 1576 and a plurality of grooves 1578 located within the central recess 1570. These mechanisms work in conjunction with the ball outline mechanism 1580 to provide the viewer with an elongated alignment aid 1544 extending from the striking face 1520 to the rear end 1534.

[0385] The centerline 1576 is located within the central recess 1570 of the recessed floor 1574. The centerline 1576 is located behind the center point of the striking face and extends along the entire length of the central recess 1570. The centerline 1576 extends perpendicularly from the striking face 1520 toward the rear end 1534. The centerline 1576 also extends parallel to the parallel line 1584 of the ball outline mechanism 1580. In some embodiments, the centerline 1576 is further recessed into the recessed floor 1574. In other embodiments, the centerline 1576 is coplanar with the recessed floor 1574. In some further embodiments, the centerline 1576 protrudes from the recessed floor 1574. The centerline 1576 helps the viewer find the center of the alignment aid 1544. The centerline 1576 is located in the center of the recessed floor 1574.

[0386] The alignment aid further comprises a plurality of grooves 1578 positioned on a recessed floor 1574 on either side of the centerline 1576. The plurality of grooves 1578 are further recessed within the recessed floor 1574. In some embodiments, the plurality of grooves 1578 are arranged at equal intervals from one another. In other embodiments, the plurality of grooves 1578 are concentrated near the centerline 1576 or near the toe end 1512 and heel end 1516. The plurality of grooves 1578 are the centerline 1576 and parallel line 1584 of the ball outline mechanism 1580, and are parallel. The plurality of grooves 1578 provide a series of alignment lines perpendicular to the striking face 1520, thereby further assisting the viewer in correctly aligning the golf ball.

[0387] As described above, each mechanism of the alignment assist unit 1544 assists the viewer in aligning the putter-type club head 1500 with the golf ball. The ball outline mechanism 1580 is approximately the width of a golf ball and generally resembles a rectangular golf ball. The ball outline mechanism 1580 allows the user to outline the edges of the golf ball with parallel lines and border the ball. The center line 1576 is located in the center of the ball outline mechanism 1580 and behind the center point of the striking face, assisting the viewer in aligning the center of the golf ball with the center of the putter-type club head 1500. Multiple grooves 1578 are parallel to the parallel lines 1584 and the center line 1576 and further assist the user in aligning the golf ball perpendicular to the putter-type club head 1500.

[0388] The alignment assist section 1544 further utilizes the central recess 1570. The central recess 1570 provides a structure for the ball outline mechanism 1580 to draw its outline. The central recess 1570 also accommodates the center line 1576 and multiple grooves 1578. The ball outline mechanism 1580 is positioned near the upper surface 1526, and the center line 1576 and multiple grooves 1578 are positioned on the recess floor 1574, vertically offset from the ball outline mechanism 1580. When the putter-type club head 1500 is viewed from above or below, the center line 1576 appears to be slightly offset from the ball outline mechanism. This offset contributes to the positioning of the ball outline mechanism 1580 on the upper surface 1526 and the center line 1576 on the recess floor 1574. Also, when viewed from above and below, as shown in Figure 15D, the recess wall 1572 disappears when the putter-type club head 1500 is aligned. Different parts of the alignment assist unit 1544 work in conjunction with the central recess 1570 to assist the user in aligning the golf ball. The alignment assist unit 1544 may include multiple colors to help viewers identify the different mechanisms of the alignment assist unit 1544.

[0389] Each part of the alignment aid 1544 includes a color. The ball outline mechanism 1580 includes a first color, and the centerline 1576 includes a second color. Furthermore, the upper part 1504 includes a third color. The colors can be white, black, gray, silver, red, blue, yellow, green, orange, purple, or any other suitable color. In some embodiments, the first, second, and third colors are similar. In other embodiments, the first, second, and third colors are different from each other. The different colors provide a visual contrast between the different mechanisms of the alignment aid 1544, which helps the viewer to identify the different mechanisms.

[0390] In some embodiments, contrasts are defined by colors that are opposite to each other. For example, the first, second, or third color may be a primary color selected from the group consisting of red, yellow, and blue, while the other of the first, second, or third color may be a secondary color selected from the group consisting of green, orange, and purple. Alternatively, the first, second, or third color may be white or black, while the other of the first, second, or third color may be the other of white or black. The different or contrasting colors of each mechanism further assist the viewer's alignment by improving the viewer's brain's ability to detect misalignment between parallel lines. This is a phenomenon known as vernier visual acuity.

[0391] The arrangement of the parallel lines 1584 and center line 1576 of the ball outline mechanism 1580 utilizes the viewer's vernier visual acuity. In some embodiments, the positioning and contrasting colors of the parallel lines 1584 of the ball outline mechanism 1580 and center line 1576 allow the viewer's eye to remain still and naturally focused on the center line 1576, enabling better alignment of the target golf ball. In some embodiments, the ball outline mechanism 1580 and center line 1576 are filled with paint. The shading and sizing of the mechanism are generally selected to provide an alignment aid 1544 that resembles a golf ball.

[0392] The ball outline mechanism 1580 defines the width measured between the furthest points of the parallel lines 1584. The width can be slightly larger than the width of the golf ball to provide forgiveness when rimming the golf ball. The width is between 1.65 inches and 1.80 inches. In some embodiments, the width is approximately 1.65 inches, 1.66 inches, 1.67 inches, 1.68 inches, 1.69 inches, 1.70 inches, 1.71 inches, 1.72 inches, 1.73 inches, 1.74 inches, 1.75 inches, 1.76 inches, 1.77 inches, 1.78 inches, 1.79 inches, or 1.80 inches. In one embodiment, the width is approximately 1.78 inches.

[0393] The ball outline mechanism 1580 further defines a thickness. The thickness may be large enough to provide a substantial ball outline mechanism 1580. The thickness is between 0.03 inches and 0.15 inches. In some embodiments, the thickness is approximately 0.03 inches, 0.04 inches, 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, or 0.15 inches.

[0394] The ball outline mechanism 1580 further defines the length. The length is measured in the front-to-back direction between the endpoints of the ball outline mechanism 1580. The length is between 2.9 inches and 3.1 inches. In some embodiments, the length is approximately 2.90 inches, 2.91 inches, 2.92 inches, 2.93 inches, 2.94 inches, 2.95 inches, 2.96 inches, 2.97 inches, 2.98 inches, 2.99 inches, 3.00 inches, 3.01 inches, 3.02 inches, 3.03 inches, 3.04 inches, 3.05 inches, 3.06 inches, 3.07 inches, 3.08 inches, 3.09 inches, or 3.10 inches. In one embodiment, the length is 3.08 inches.

[0395] The alignment assist unit 1544 is designed to provide a golf ball-like mechanism that is approximately the width of a golf ball. As described above, the alignment assist unit 1544 comprises different mechanisms located near or within the central recess 1570. Each mechanism provides a function to the alignment assist unit 1544, thereby enabling the user to better align the golf ball to a desired spot on the putter-type golf club head in order to achieve more accurate shots. Furthermore, the alignment assist unit 1544 utilizes the central recess 1570 to further assist in viewer alignment. The alignment assist unit 1544 and the central recess 1570 are located near the center of the putter-type club head 1500 within the front section 1522 and the rear extension 1524. The rear extension 1524 is configured to allow the upper section 1504 to receive the lower section 1508.

[0396] The lower section 1508 comprises a material of higher density than the upper section 1504 (i.e., a second material). In many embodiments, the lower section 1508 is formed from stainless steel. Referring to Figure 15B, the lower section 1508 comprises a central section 1538, a toe mass 1545, and a heel mass 1547. The central section 1538 is a thinned area relative to the toe and heel masses 1545, 1547, allowing the upper section 1504 to be accepted into the lower section 1508. The thinned central section 1538 also improves the moment of inertia of the putter-type club head 1500 by removing mass from the center of the lower section 1508, which can be reassigned to the toe and heel masses 1545, 1547. The central section 1538 includes a central upper surface 1540 adjacent to the upper lower surface 1528. The central upper surface 1540 includes a shape corresponding to the upper lower surface 1528. In some embodiments, the upper surface 1528 of the central portion includes one or more recesses, as shown in Figure 15B. One or more recesses can further reduce the mass from the center of the lower portion 1508. The mass can be redistributed to toe and heel masses 1545, 1547 configured to distribute the mass around the periphery of the putter-type club head 1500.

[0397] The toe and heel masses 1545 and 1547 are raised portions relative to the central portion 1538. The toe and heel masses 1545 and 1547 are positioned near the peripheral portion 1510, providing peripheral weighting to increase the moment of inertia of the putter-type clubhead 1500. Furthermore, the weights of the toe and heel masses 1545 and 1547 can be adjusted to achieve a desired swing weight or overall putterhead mass. The toe and heel masses 1545 and 1547 include a mass upper surface 1541 that forms part of the crown 1536. The upper 1504 and lower 1508 form part of the crown 1536 and sole 1568, respectively. The lower 1508 further includes a lower lower surface 1542 that forms part of the sole. The toe and heel masses 1545, 1547 further include an inner surface 1561 located near the toe and heel walls 1529, 1530 and an outer surface 1543 that forms part of the peripheral portion 1510. In some embodiments, the outer surface 1543 forms part of the toe end 1512, the heel end 1516, or the rear end 1534. The inner surface 1561 defines the transition between the toe mass 1545 and the central portion 1538, as well as the transition between the heel mass 1547 and the central portion 1538. The inner surface 1561 includes shapes corresponding to the toe and heel walls 1529, 1530. The lower portion 1508 is configured to receive the upper portion 1504 such that the rear extension 1524 is located above the central portion 1538 and between the toe and heel masses 1545, 1547.

[0398] In some embodiments, the toe and heel masses 1545, 1547 are formed to fit snugly with the upper part 1504. In other embodiments, the inner surface 1561 and the toe and heel walls 1529, 1530 define a gap 1595, 1597 between them. The gap 1595, 1597 allows for adjustment of the weighting of the putter-type club head 1500 by holding toe and heel masses 1545, 1547 of varying sizes within the cutout area. The gap 1595, 1597 defines the width measured between the respective inner surface 1561 and the toe and heel walls 1529, 1530. The gap width may remain constant throughout the gap 1595, 1597, or the gap width may vary throughout the gap 1595, 1597. The gap width can be between 0.05 inches and 0.21 inches. In some embodiments, the gap width is between 0.05 inches and 0.09 inches, 0.07 inches and 0.13 inches, 0.10 inches and 0.18 inches, and 0.15 inches and 0.21 inches. In some embodiments, the gap width is 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, or 0.21 inches. In one embodiment, the gap width is 0.16 inches. The gap width varies depending on the toe and heel masses 1545, 1547, and the size and shape of the corresponding notch area.

[0399] The toe and heel masses 1545 and 1547 can each be one or a combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircular, square, cylindrical, oval, elliptical, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape. The shapes of the toe and heel masses 1545 and 1547 correspond to the shapes of the respective notched areas of the upper part 1504.

[0400] The toe and heel masses 1545 and 1547 provide additional means to add mass to the periphery 1510 to increase the MOI of the putter-type club head 1500 on the putter, without these mass mechanisms. The lower part 1508 includes a mass between 200 grams and 215 grams. In some embodiments, the mass is between 200 grams and 210 grams, 205 grams and 210 grams, and 210 grams and 215 grams. The mass may be 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, or 215 grams. In one embodiment, the mass is 205.7 grams.

[0401] The lower, as well as the toe and heel masses 1545 and 1547, provide a region of concentrated mass, particularly near the periphery 1510, and as a result, the toe and heel masses 1545 and 1547 function to increase the moment of inertia of the putter-type club head 1500. Placing the toe and heel masses 1545 and 1547 near the periphery 1510 increases the MOI because each mass is farther from the center of gravity of the putter-type club head 1500. The upper 1504 is attached to the lower 1508, which is formed using a second material, the second material being denser than the first material. The upper 1504 can be attached to the lower 1508 using adhesive.

[0402] In many embodiments, the lower section 1508 comprises less than 35% of the total volume of the putter-type club head 1500. In some embodiments, the lower section 1508 comprises less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, or less than 23% of the total volume. In one embodiment, the lower section 1508 comprises 30.1% of the total volume.

[0403] The lower part 1508 comprises less than half the volume of the putter-type club head 1500, but includes at least 50% of the total mass of the putter-type club head 1500. In some embodiments, the lower part 1508 comprises at least 51%, at least 52%, at least 53%, at least 54%, at least 55%, at least 56%, at least 57%, at least 58%, at least 59%, or at least 60% of the total mass. In one embodiment, the lower part 1508 comprises 56.1% of the total mass. As will be described in more detail below, the lower part 1508 comprises a low proportion (less than 50%) of the volume of the putter-type club head 1500 and a high proportion (greater than 50%) of the mass of the putter-type club head 1500.

[0404] The combination of a low-density upper section 1504 and a high-density lower section 1508 forms a high-MOI putter-type club head 1500 without creating an extremely heavy putter. The central recess 1570 shifts most of the volume and mass of the putter-type club head 1500 to the peripheral section 1510. This shift forms a small portion that increases the MOI compared to a putter milled from a single material. A single-material putter-type club head cannot allocate high-density material to the periphery while maintaining the desired volume (75cc-100cc) and mass (340g-385g). The advantages of the putter head 1500 over a putter head formed from a single-material structure are illustrated in the following example.

[0405] IV. Putter head with ball outline alignment aid and individual weights In one embodiment, the putter-type club head may include a two-part structure and may include an alignment aid having a ball outline mechanism. The two-part structure allows the putter-type club head to be formed from multiple materials. Referring to Figures 16A and 16B, the putter-type club head 1600 comprises a body 1604, a toe weight 1645, and a heel weight 1647. In some embodiments, the body 1604 is formed from a first material having a first density, and the toe and heel weights 1645, 1647 are formed from a second material having a second density. In some embodiments, the first density is less than the second density. As will be described in more detail below, the body 1604 and the toe and heel weights 1645, 1647 are formed from a high MOI putter-type club head 1600 (5000 g·cm²) while maintaining the desired volume and mass. 2 ~6500g·cm 2 They are combined to produce ). For example, a putter head 1600 has a weight of 5000 g·cm. 2 ~5500g·cm 2 5500g·cm 2 ~6000g·cm 2 6000g·cm 2 ~6500g·cm 2 The MOI can be in the range of . The putter head 1600 includes a 2% to 15% increase in MOI around the y-axis compared to a putter head lacking a multi-material structure (i.e., single material). For example, the putter head 1600 includes increases of 2% to 5%, 5% to 10%, or 10% to 15% compared to a single-material putter.

[0406] The putter-type club head 1600 further comprises a crown 1636, a sole 1668, a striking face 1620, a rear end 1634, a toe end 1612, and a heel end 1616. The outermost points of the striking face 1620, the rear end 1634, the toe end 1612, and the heel end 1616 define the periphery 1610 of the putter-type club head 1600. The body 1604 and the toe and heel weights 1645, 1647 form part of the crown 1636, part of the sole 1668, part of the toe end 1612, part of the heel end 1616, and part of the periphery 1610, respectively. The crown 1636 gradually slopes from the striking face 1620 to the rear end 1634, resulting in the putter-type club head 1600 being thicker near the striking face 1620 and gradually thinning towards the rear end 1634. The slope of the crown 1636 can be a linear, curved, parabolic, sinusoidal, or polynomial function. Furthermore, the striking face 1620 includes a striking face center point that is equidistant from the heel end 1616 and the toe end 1612, and equidistant from the crown 1636 and the sole 1668.

[0407] In many embodiments, the sole 1668 may be planar. In some embodiments, the sole 1668 may have a slight curve from the heel 1616 to the toe 1612, the slight curve may be linear or a polynomial function. In some embodiments, the sole 1668 may have a strong curve from the heel 1616 to the toe 1612, the strong curve may be linear or a polynomial function. The sole 1568 functions to provide a surface for placing the putter-type club head 1600 on the ground plane. As described above, the putter-type club head 1600 includes a body 1604, a toe weight 1645, and a heel weight 1647, the body 1604 forming the majority of the sole 1668 and lies on the ground plane. The toe weight 1645 and heel weight 1647 sit on top of the body 1604 when the putter-type club head 1600 is assembled.

[0408] As described above, the body 1604 comprises a low-density material (i.e., the first material). In many embodiments, the body 1604 is formed from aluminum. The toe weight 1645 and heel weight 1647 are attached to the body 1604 to define the crown 1636, sole 1668, toe end 1612, heel end 1616, and perimeter 1610. The body 1604 includes an upper surface 1626 and a lower surface 1628, the upper surface 1626 forming part of the crown 1636 and the lower surface 1628 forming part of the sole 1668. The body 1604 further includes a front portion 1622 and a rear portion 1623, the front portion 1622 including the striking face 1620. The rear portion 1623 includes a rear extension 1624 extending rearward from the front portion 1622 toward the rear end 1634. The rear extension 1624 is generally perpendicular to the striking face 1620. The front portion 1622 and the rear extension 1624 form a T-shape.

[0409] The body 1604 defines a central recess 1670 that extends from the front portion 1622 to the rear portion 1634. The central recess 1670 removes mass from the central portion of the body 1604, thereby allowing the mass to move toward the peripheral portion 1610. The central recess 1670 is defined by a recess wall 1672 and a recess floor 1674. The recess floor 1674 is recessed into the body 1604 away from the body top surface 1626, and the recess wall 1672 is circumscribing the recess floor 1674.

[0410] The recessed wall 1672 includes height. In some embodiments, the recessed wall height slopes with the inclination of the crown 1636, resulting in the recessed wall height being greater near the striking face 1620 and smaller near the rear end 1634. In such embodiments, the recessed wall 1672 includes height near the rear end 1634 so that the recessed floor 1674 is not coplanar with the body top surface 1626. In other embodiments, the recessed wall height remains constant throughout the central recess 1670. The recessed floor 1674 is parallel to the ground plane and provides a surface parallel to the ground plane to a portion of the alignment aid 1644. The central recess 6570 is located near the center of the putter-type club head 1600 within the front portion 1622 and the rear extension 1624 and provides the central mechanism for the alignment aid 1644. The central recess 1670 further contributes to the alignment aid 1644, as will be described in more detail below.

[0411] The body 1604 further comprises an alignment aid 1644. The alignment aid 1644 is similar to the alignment aid 1544 and is described using the same reference number as the alignment aid 1544. For example, the alignment aid includes a set of one or more curved sections 1682 and parallel lines 1684, which are similar to the set of one or more curved sections 1582 and parallel lines 1584 of the alignment aid 1544. However, the alignment aid 1544 is located on the upper body surface 1626 instead of the upper top surface 1526, as is the case with the alignment aid 1544.

[0412] The alignment aid 1644 includes a ball outline mechanism 1680, a center line 1676, and a plurality of grooves 1678. The ball outline mechanism 1680 may be similar to the ball outline mechanism 1580 shown in Figures 15D-15E. For example, the ball outline mechanism 1680 may partially or completely surround the central recess 1670. In some embodiments, the parallel lines 1684 connect a plurality of arc-shaped sections 1682 to form a circular or rectangular ball outline mechanism 1680 that completely circumscribes the central recess 1670, as shown in Figure 15D. In other embodiments having only one arc-shaped section 1682, the parallel lines 1684 extend rearward, thereby defining a U-shaped ball outline mechanism 1680 that partially circumscribes the central recess 1670. In some embodiments, the parallel lines 1684 extend completely to the rear end 1634, as shown in Figure 15E. In other embodiments, the parallel lines 1684 extend partially to the rear end 1634, as shown in Figure 15F. The ball outer shape mechanism 1680 is generally aligned around the central recess 1670 and positioned on the upper body surface 1626.

[0413] Furthermore, the centerline 1676 and the multiple grooves 1678 may be similar to the centerline 1576 and multiple grooves 1578 of the alignment aid 1544. The centerline 1676 and the multiple grooves 1678 are located on the recessed floor 1674. The centerline 1676 is located behind the center point of the striking face and extends along the entire length of the central recess 1670. The multiple grooves 1678 are recessed in the recessed floor 1674 on both sides of the centerline 1676. Each mechanism of the alignment aid 1644 assists the viewer in aligning the putter-type club head 1600 with the golf ball. The alignment aid 1644 also utilizes the central recess 1670, which provides a structure for the ball shaping mechanism 1670 to outline the ball. The central recess 1670 also houses the centerline 1676 and the multiple grooves 1678. As described above, the alignment assist section 1644 is positioned near the upper body surface 1526 and extends from the front section 1622 through the rear extension 1623 to the rear end 1634. The rear section 1623 is further configured to receive one or more weights.

[0414] The rear section 1623 further comprises toe wings 1629 and heel wings 1630 that receive toe weights 1645 and heel weights 1647. The wings 1629, 1630 are positioned near the periphery 1610 toward the rear end 1634 such that the rear extension 1624 extends between the wings 1629, 1630. The wings 1629, 1630 are defined between the wing floor 1632 and the sole 1668. The wing floor 1632 is recessed into the body 1604, away from the body top surface 1626. The wing floor 1632 forms the base for the wings 1629, 1630 to receive the weights 1645, 1647.

[0415] The rear section defines a toe weight recess 1638 and a heel weight recess 1639. The weight recesses 1638 and 1639 are located above the wings 1629 and 1630 and function to accommodate weights 1645 and 1647. The weight recesses 1638 and 1639 are defined by the wing wall 1631 and the wing floor 1632, with the wing wall 1631 adjacent to each recess floor 1632. The toe weight recess 1638 extends inward from the toe end 1612 toward the center of the body 1604. The heel weight recess 1639 extends from the heel end 1616 toward the center of the body 1604. The weight recesses 1638 and 1639 are enclosed by the crown 1636, the perimeter 1610, the recess floor 1632, and the wing wall 1631.

[0416] The wing wall 1631 defines the boundary between the wings 1629, 1630 and the front portion 1622, as well as the boundary between the wings 1629, 1630 and the rear extension 1624. In some embodiments, the wing wall 1631 can completely encompass the weights 1645, 1647. In other embodiments, the wing wall 1631 can partially encompass the weights 1645, 1647. For example, in some embodiments, the wing wall 1631 can encompass between 30% and 45%, 40% and 65%, 50% and 90%, or 60% and 95% of the weights 1645, 1647.

[0417] The wing recesses 1638, 1369 are configured to receive the weights 1645, 1647 so that they sit on the wings 1629, 1630. Referring to Figure 16B, the wings 1629, 1630 include mounting points 1633 that receive the respective weights 1645, 1647. Each mounting point 1633 protrudes from the wing floor 1632 into the respective weight recesses 1638, 1639. Each mounting point 1633 can be one or a combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircle, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape.

[0418] The weight recesses 1638, 1369 and wings 1629, 1630 can include any desired shape. However, in many embodiments, the weight recesses 1638, 1369 and wings 1629, 1630 include shapes similar to or identical to the shapes of the weights 1645, 1647. Each weight recess 1638, 1369 corresponds to the respective wings 1629, 1630 and mounting point 1633 of the respective weights 1645, 1647.

[0419] Referring to Figure 16A, the putter-type club head 1600 includes heel weights 1647 and toe weights 1645 corresponding to the respective wings 1629, 1630, weight recesses 1638, 1639, and mounting point 1633. However, the putter-type club head 1600 is not limited to heel weights 1647 and toe weights 1645. In some embodiments, the putter-type club head 1600 may include 1, 2, 3, 4, 5, 6, 7, or 8 weights. In these embodiments, the putter-type club head 1600 may include 1, 2, 3, 4, 5, 6, 7, or 8 corresponding wings and mounting points.

[0420] Weights 1645 and 1647 comprise a material of higher density than body 1604 (i.e., a second material). In many embodiments, weights 1645 and 1647 are formed from stainless steel. Weights 1645 and 1647 are positioned near the perimeter 1610 and are fixed to body 1604. Referring to Figures 16B and 16D, weights 1645 and 1647 comprise an inner surface 1661 located near the wing wall 1631 and an outer surface 1643 that forms part of the perimeter 1610. In some embodiments, the outer surface 1643 forms part of the toe end 1612, heel end 1616, or rear end 1634. The inner surface 1661 comprises a shape corresponding to the wing wall 1631.

[0421] In some embodiments, the weights 1645, 1647 fit snugly with the body 1604. In other embodiments, the inner surface 1661 and wing wall 1631 define gaps 1695, 1697 between them. The gaps 1695, 1697 allow for weights of varying sizes 1629, 1630 to be held in weight recesses 1638, 1639 to adjust the weighting of the putter-type club head 1600. The gaps 1695, 1697 define the width measured between the respective inner surface 1661 and wing wall 1631. The gap width may remain constant throughout the gaps 1695, 1697, or the gap width may vary throughout the gaps 1695, 1697. The gap width may be between 0.05 inches and 0.21 inches. In some embodiments, the gap width is between 0.05 inches and 0.09 inches, 0.07 inches and 0.13 inches, 0.10 inches and 0.18 inches, and 0.15 inches and 0.21 inches. In some embodiments, the gap width is 0.05 inches, 0.06 inches, 0.07 inches, 0.08 inches, 0.09 inches, 0.10 inches, 0.11 inches, 0.12 inches, 0.13 inches, 0.14 inches, 0.15 inches, 0.16 inches, 0.17 inches, 0.18 inches, 0.19 inches, 0.20 inches, or 0.21 inches. In one embodiment, the gap width is 0.16 inches.

[0422] Weights 1645 and 1647 further include a weight upper surface 1640 and a weight lower surface 1642. The weight upper surface 1640 forms part of the crown 1636, and the weight lower surface 1642 forms part of the sole 1668. The weight lower surface 1642 is adjacent to the wing base 1632 and includes shapes corresponding to the respective wings 1629, 1630 and mounting points 1633. Referring to Figure 16D, the weight lower surface 1642 has a stepped shape corresponding to the shapes of the respective wings 1629, 1630 and mounting points 1633. Weights 1645 and 1647 slide on the mounting points 1633 and are further secured with epoxy material. In some embodiments, the wing base 1632 includes multiple grooves that increase the surface area of ​​the wing base 1632. The multiple grooves increase the surface area available for bonding, thereby strengthening the bond between weights 1645 and 1647 and the base 1632. The shape of the lower surface 1642 of the weight facilitates a tight connection between the weights 1645 and 1647 and the wings 1629 and 1630.

[0423] Weights 1645 and 1647 can be any one or a combination of the following shapes: rectangle, triangle, pyramidal, sphere, semicircle, square, cylindrical, oval, ellipse, trapezoid, pentagon, hexagon, octagon, or any other desired geometric or non-geometric shape. The geometric shapes of weights 1645 and 1647 correspond to the geometric shapes of weight recesses 1638 and 1639, respectively.

[0424] Weights 1645 and 1647 provide additional means of adding mass to the periphery 1610 to increase the MOI of the putter-type club head 1600 on putters without these mass mechanisms. Furthermore, weights 1645 and 1647 can be adjusted to achieve a desired swing weight or overall putter head mass. Weights 1645 and 1647 have combined masses between 45 grams and 70 grams. In some embodiments, the masses are 45 grams to 60 grams, 55 grams to 70 grams, and 55 grams to 65 grams. Combined masses are 45 grams, 46 grams, 47 grams, 48 ​​grams, 49 grams, 50 grams, 51 grams, 52 grams, 53 grams, 54 grams, 55 grams, 56 grams, 57 grams, 58 grams, 59 grams, 60 grams, 61 grams, 62 grams, 63 grams, 64 grams, 65 grams, 66 grams, 67 grams, 68 grams, 69 grams, or 70 grams. Weights 1645 and 1647 provide a region of concentrated mass near the periphery 1610 so that each weight 1645 and 1647 functions to increase the moment of inertia of the putter-type club head 1600. Because each mass is far from the center of gravity of the putter-type club head 1600, placing each weight 1645 and 1647 near the periphery 1610 increases the MOI. Each weight 1645 and 1647 is fixed to the body 1604 using a second material, which is denser than the first material.

[0425] In many embodiments, the weights 1645 and 1647 comprise less than 25% of the total volume of the putter-type club head 160. In some embodiments, the weights 1645 and 1647 comprise less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, or less than 13% of the total volume.

[0426] Weights 1645 and 1647 comprise less than half of the total volume of the putter-type club head 160, but represent at least 30% of the total mass of the putter-type club head 160. In some embodiments, weights 1645 and 1647 comprise at least 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% of the total mass.

[0427] The combination of a low-density body 1604 and high-density weights 1645 and 1647 makes it possible to create a high-MOI putter-type club head 1600 without creating an extremely heavy putter. The central recess 1670 shifts most of the volume and mass of the putter-type club head 1600 to the edges of the body 1604. This shift forms a small portion that increases the MOI compared to a putter milled from a single material. A single-material putter-type club head cannot allocate high-density material to the periphery while maintaining the desired volume (75cc-100cc) and mass (340g-385g).

[0428] V.3 Part Putter Head In some embodiments, instead of a two-part putter, a putter-type golf club head may have a three-part structure including a crown portion 1802 in addition to the upper and lower parts. By providing a three-part putter head including a crown portion 1802 in addition to the upper and lower parts, the overall mass distribution of the putter head can be more precisely controlled and optimized, thereby increasing the MOI of the putter head.

[0429] The upper part of the three-part putter-type golf club head can be similar to one or more upper parts described with reference to a conventional embodiment and can be made of the first material described above. Similarly, the lower part of the three-part putter-type golf club head can be similar to one or more lower parts described with reference to a conventional embodiment and can be made of the second material described above.

[0430] A three-part putter head further includes a crown portion made of a third material different from both the upper first material and the lower second material. The third material may be lightweight and may have a density lower than both the first and second densities. In many embodiments, the crown portion 1802 can be joined onto the upper part to form the top of the putter head.

[0431] In many embodiments, the crown portion of the putter head having the third material has a third density in the range of 0.5 g / cc to 3.5 g / cc. The third density may be in the range of 1.5 g / cc to 2.5 g / cc. In some embodiments, the third density may be in the range of 0.5 to 0.75 g / cc, 0.75 to 1.0 g / cc, 1.0 to 1.25 g / cc, 1.25 to 1.5 g / cc, 1.5 to 1.75 g / cc, 1.75 to 2.0 g / cc, 2.0 to 2.25 g / cc, 2.25 to 2.5 g / cc, 2.5 to 2.75 g / cc, 2.75 to 3.0 g / cc, or 3.25 to 3.5 g / cc. In one embodiment, the third density of the crown portion 1802 may be in the range of 1.0 to 2.0 g / cc. In some embodiments, the third density may be less than 3.5 g / cc, less than 3.0 g / cc, less than 2.5 g / cc, less than 2.0 g / cc, less than 1.5 g / cc, or less than 1.0 g / cc. In some embodiments, the third density may be 0.5 g / cc, 0.75 g / cc, 1.0 g / cc, 1.25 g / cc, 1.50 g / cc, 1.75 g / cc, 2.0 g / cc, 2.25 g / cc, 2.50 g / cc, 2.75 g / cc, 3.0 g / cc, 3.25 g / cc, or 3.50 g / cc.

[0432] The crown portion of a putter head having a third material can be made from any one or a combination of the following: aluminum, aluminum alloy, ADC-12, polymer material, composite material, filled thermoplastic, fiber-reinforced composite material, or other suitable low-density material.

[0433] The MOI of the putter head can be increased by including a low-density crown section. Replacing the parts of the club head made of the first or second material creates any mass that can be redistributed throughout the putter head.

[0434] a.3 Partial Spade Shape Embodiment Figures 18A-18D show a first embodiment of a three-part putter-shaped golf club head 1800. In this embodiment, the putter head 1800 is a spade-shaped putter head 1800, similar to the two-part spade-shaped putter head 700 in Figures 7A-7C. The three-part spade-shaped putter head 1800 comprises an upper part 1804, a lower part 1808, and a crown part 1802, and a hollow internal cavity 1850 formed between the upper part 1804, the lower part 1808, and the crown part 1802. The upper part 1804 is made of a first material having a first density, the lower part 1808 is made of a second material having a second density, and the crown part 1802 is made of a third material having a third density. The first density is less than the second density. The third density is less than both the first and second densities. The upper part 1804, lower part 1808, and crown part 1802 are combined to create a high MOI putter head (3500 g·cm²) while maintaining the desired volume and mass. 2 ~5000g·cm 2 ) Create 1800. For example, in some embodiments, the putter head 1800 is approximately 3500 g·cm 2 From 4000g·cm 2 , about 4000g cm 2 From 4500g·cm 2 , or approximately 4500g·cm 2 From 5000g·cm 2 It can have an MOI between these two values. In some embodiments, the putter head 1800 has an MOI of approximately 3500 g·cm². 2 From 3750g·cm 2 , approx. 3750g cm 2 From 4000g·cm 2 , about 4000g cm 2 From 4250g·cm 2, approx. 4250g cm 2 From 4500g·cm 2 , about 4500g cm 2 From 4750g·cm 2 , or approximately 4750g·cm 2 From 5000g·cm 2 It is possible to have a MOI between these points.

[0435] As shown in Figure 18A, the upper section 1804 forms the majority of the body of the putter head 1800. The upper section 1804 comprises a base 1830 and several walls extending vertically from the base 1830. The upper section 1804 may comprise several peripheral walls, including a front wall 1812, a toe wall 1814, a heel wall 1816, and a rear wall 1832 that define the striking face 1820. The front wall 1812 is adjacent to the toe wall 1814 and the heel wall 1816 and is opposite the rear wall 1832. The outer surface of the front wall 1812 forms the striking face 1820, while the inner surface of the front wall 1812 forms the back surface 1824. The toe wall 1814 is adjacent to the front wall 1812 and the rear wall 1832 and is opposite the heel wall 1816. Heel wall 1816 is also adjacent to front wall 1812 and rear wall 1832, but is on the opposite side from toe wall 1814.

[0436] Multiple perimeter walls can form a large portion of the perimeter of the putter head 1800. The base 1830 can extend from the front wall 1812 to the rear wall 1832, and from the toe wall 1814 to the heel wall 1816. The base 1830 further comprises an upper surface 1831 and a lower surface 1833 opposite the upper surface 1831. The lower surface 1833 of the base 1830 forms at least a portion of the sole 1868. In many embodiments, referring to Figure 18C, the lower surface 1833 may include a recessed area 1840 configured to receive the lower part 1808 such that the lower surface 1833 of the base 1830 forms a portion of the sole 1868 and the lower surface 1882 of the lower part 1808 forms the rest of the sole 1868.

[0437] The upper section 1804 further comprises a plurality of inner walls 1838 extending vertically from the base 1830. Each of the plurality of inner walls 1838 is inserted around the periphery of the putter head 1800. Thus, the plurality of inner walls 1838 do not form any portion around the club head. As shown in Figure 18A, the plurality of periphery walls and the plurality of inner walls 1838 can be interconnected. The interconnections between the plurality of periphery walls and the plurality of inner walls 1838, when viewed from above, can collectively form a cavity profile, which defines the shape of the hollow inner cavity 1850. The shape of the cavity profile is defined by the orientation and shape of the plurality of periphery walls and the plurality of inner walls 1838. In some embodiments, for example, as shown in the embodiment in Figure 18A, the upper 1804 may comprise one or more inner walls 1838 extending substantially perpendicular to the striking face 1820 and one or more inner walls 1838 extending substantially parallel to the striking face 1820. In other embodiments, one or more inner walls 1838 may extend at an angle to the striking face 1820. Although Figure 18A shows that the multiple inner walls 1838 are formed as substantially straight walls, in other embodiments the putter head 1800 may comprise one or more curved inner walls 1838. The top of the upper 1804 may be open so that the upper 1804 itself does not enclose a hollow portion or an internal cavity.

[0438] The upper portion 1804 can further define one or more outer portions 1835 located outside the cavity profile. One or more outer portions 1835 form the area of ​​the putter head 1800, and the upper surface 1831 of the base 1830 is exposed to the outside of the putter head 1800. One or more outer portions 1835 can be partially bounded by the outer surfaces of one or more inner walls 1838, but the outer portions 1835 are not bounded on either side by any of the multiple perimeter walls.

[0439] The upper section 1804 further comprises a central opening 1864 extending through a portion of the base 1830. The central opening 1864 extends through both the upper surface 1831 and the lower surface 1833 of the base 1830. The central opening 1864 shifts the majority of the volume and mass of the putter head 1800 to the edge of the upper section 1804. The central opening 1864 can be configured to be covered by the lower section 1808 so as to surround a hollow internal cavity 1850.

[0440] As shown in Figures 18A and 18B, the crown portion 1802 forms the majority of the upper surface of the putter head 1800. The crown portion 1802 may include a thin, cover-like structure configured to cover the upper portion 1804. Multiple walls can provide the surface 1834 to which the crown portion 1802 is attached. As shown in Figure 18A, the shape of the crown portion 1802 is complementary to the shape of the upper portion 1804. In particular, the shape of the crown corresponds to the cavity profile formed by the multiple upper walls. The peripheral edge of the crown portion 1802 can be configured to attach to the upper surface 1834 of the upper peripheral wall and the upper inner wall 1838. As shown in Figure 18(b), the crown portion 1802 completely encloses the upper part of the hollow inner cavity 1850 by covering the upper part of the lower portion 1808.

[0441] The crown section 1802 includes a front edge 1870 that extends from heel to toe along the front wall 1812. The front edge 1870 can extend all the way from the toe wall 1814 to the heel wall 1816. The crown section 1802 further includes a central extension 1842, a heel extension 1846, and a toe extension 1848. The central extension 1842 extends rearward from the front edge 1870 near the center of the front wall 1812. The central extension 1842 extends all the way from the front wall 1812 to the rear wall 1832, covering the central region of the cavity profile. The heel extension 1846 extends rearward from the heel side of the front edge 1870. The heel extension 1846 extends along the heel wall 1816, extending part of the path from the front wall 1812 to the rear wall 1832. The toe extension 1848 extends rearward from the toe side of the front edge 1870. The toe extension 1848 extends along the toe wall 1814 and extends a portion of the path from the front wall 1812 to the rear wall 1832.

[0442] Furthermore, the crown portion 1802 of the putter head 1800 may be equipped with one or more alignment mechanisms 1836. The alignment mechanism 1836 may be a line, a series of lines, a milled trough, a circle, a dashed line, a triangle, a channel, or any other desired alignment mechanism 1836, either one or a combination thereof. In the embodiments of Figures 18A to 18D, the central extension 1842 is configured to be the width of a golf ball (approximately 4.27 cm). The alignment mechanisms 1836 extending along the crown portion 1802 function to provide the viewer with a visual alignment field that extends the width of a golf ball from the striking face 1820 to the rear of the putter head 1800. The objective is to use these alignment mechanisms 1836 along the crown portion 1802 to align the entire putter head 1800 with a golf ball.

[0443] As shown in Figure 18D, the lower section 1808 can form the majority of the sole 1868. The lower section 1808 can be formed as a substantially flat, high-density sole plate. In many embodiments, the lower section 1808 is received within a recessed region 1840 of the lower surface 1833 of the upper section. The lower section 1808 can be received within the upper section 1804 such that the lower surface 1882 of the lower section 1808 lies coplanar with the lower surface 1833 of the upper section 1804. In this way, the upper section 1804 and the lower surfaces 1833, 1882 of the lower section 1808 combine to define a substantially continuous sole surface at the bottom of the putter head 1800. In some embodiments, referring to Figure 18A, the upper surface 1880 of the lower section 1808 can include one or more recesses 1886. One or more recesses 1886 can be located near the center of the lower section 1808. One or more recesses 1886 can help shift mass toward the periphery of the lower section 1808.

[0444] Referring to Figure 18D, the lower section 1808 is positioned toward the rear wall 1832 of the putter head 1800 and can substantially extend between the heel wall 1816 and the toe wall 1814. Thus, the majority of the sole 1868 adjacent to the rear wall 1832 is formed by the lower surface 1882 of the lower section. In many embodiments, the lower section 1808 can be spaced rearward from the front wall 1812. Thus, the majority of the sole 1868 adjacent to the striking face 1820 can be formed by the lower surface 1833 of the upper section 1804.

[0445] The lower section 1808 is configured to receive from the bottom of the putter head 1800 so as to cover the upper opening 1864. The lower section 1808 can seal off the hollow internal cavity 1850 from the sole 1868 and surround the bottom of the hollow internal cavity 1850.

[0446] When joined, the upper 1804, lower 1808, and crown portion 1802 form a hollow internal cavity 1850 within the putter head 1800. The hollow internal cavity 1850 is enclosed between the inner surfaces of the peripheral wall and inner wall 1838 of the upper 1804, the lower surface (not shown) of the crown portion 1802, and the upper surface 1880 of the lower 1808. The hollow internal cavity 1850 removes a large amount of mass from near the center of gravity. As a result, the hollow internal cavity 1850 increases the MOI of the putter head 1800 by shifting the mass toward the periphery of the putter head 1800.

[0447] In the embodiments shown in Figures 18A to 18D, the hollow internal cavity 1850 is completely enclosed by the upper part 1804, the lower part 1808, and the crown portion 1802, resulting in no opening from the outside of the putter head 1800 to the hollow internal cavity 1850. By completely enclosing the internal cavity 1850 with the upper part 1804, the lower part 1808, and the crown portion 1802, the putter head 1800 is provided with a high MOI of a hollow putter head while maintaining the appearance of a solidly constructed putter head.

[0448] In some embodiments, the hollow internal cavity 1850 may be provided with a filler material (not shown). In some embodiments, the filler material may completely fill the volume of the hollow internal cavity 1850. In other embodiments, only a portion of the volume of the hollow internal cavity 1850 may be filled. In some embodiments, the filler material may fill more than 5%, more than 10%, more than 20%, more than 30%, more than 40%, more than 50%, more than 60%, more than 70%, more than 80%, or more than 90% of the volume of the hollow internal cavity 1850. In other embodiments, the filler material may fill less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5% of the volume of the hollow internal cavity 1850.

[0449] In many embodiments, the filler material may be a polymer. The polymer may include thermoplastics, thermoplastic elastomers, polyurethanes, ethylene, vinyl acetate, ethylene vinyl acetate (EVA), polyolefin copolymers, styrene, styrene-butadiene, polymer foaming materials, any other suitable polymer materials, or any combination thereof. In other embodiments, the filler material may include elastomers, polyurethane elastomers, silicones, silicone elastomers, rubber, or vulcanized natural rubber latex. Still in other embodiments, the filler material may be epoxy, resins, adhesives, polyurethane adhesives, glues, or any other suitable adhesive. For example, the carrier may be a polyurethane adhesive such as Gorilla Glue (Gorilla Glue Company, Cincinnati, Ohio). In another example, the filler material may be a polyurethane elastomer such as Freeman 1040 (Freeman Manufacturing & Supply Company, Avon, Ohio), or a polyurethane-based thermoplastic elastomer such as Freeman 3040 (Freeman Manufacturing & Supply Company, Avon, Ohio). In some embodiments, the filler material may be a lattice material. The lattice packing material can be formed from metal using processes such as casting, die casting, co-die casting, additive manufacturing, or metal 3D printing.

[0450] The combination of a low-density first material upper 1804 and a low-density third material crown portion 1802 with a high-density second material lower 1808 creates a high MOI putter head 1800 without creating an extremely heavy putter head 1800. By providing a hollow internal cavity 1850, it becomes possible to include a high-density but small amount of lower 1808, which increases the MOI of the putter head 1800 compared to a putter head milled from a single material. A single-material putter head does not allocate high-density material to the periphery while maintaining the desired volume (75cc-100cc) and mass (340g-385g). In one example, the putter head 1800 contains a high MOI, a desired volume (91cc), and a desired mass (361g).

[0451] In most embodiments, the lower part 1808 comprises less than 40% of the total volume of the putter head 1800. In some embodiments, the lower part 1808 comprises less than 39%, less than 38%, less than 37%, less than 36%, less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, or less than 30% of the total volume of the putter head 1800.

[0452] The inclusion of the hollow internal cavity 1850 allows for the concentration of the majority of the putter head 1800's mass into the lower section 1808 without creating an extremely heavy putter head 1800. The lower section 1808 contains less than 40% of the volume of the putter head 1800, but it contains at least 60% of the putter head 1800's total mass. In some embodiments, the lower part 1808 includes at least 61%, at least 62%, at least 63%, at least 64%, at least 65%, at least 66%, at least 67%, at least 68%, at least 69%, or at least 70% of the mass of the putter head 1800.

[0453] The beneficial shift of mass towards the periphery of the putter head 1800 due to the use of high-density, low-volume lower 1808 and the inclusion of a hollow internal cavity 1850 increases the MOI of the putter head 1800. The putter head 1800 has an increased MOI compared to a putter head with the same volume, mass, and single-material construction (i.e., a putter head milled from a single stainless steel block, or a putter head skin casting of a single material).

[0454] VI. Benefits Putter-type golf club heads offer the benefits of MOI, CG, feel, and weighting without the use of upper and lower parts of different densities and / or mechanically fixed weights or weight ports. By creating the upper and lower parts of the putter-type golf club head from two different materials, the weighting of the club head shifts toward the periphery of the putter-type golf club head without weight ports or attachments to the heel and toe ends of the putter-type golf club head. This shift of weight toward the periphery of the putter-type golf club head increases the MOI of the club head around the y-axis (Iyy), thus preventing rotation around the y-axis and ensuring that the striking face is perpendicular to the golf ball at impact. The increase in MOI around the y-axis helps achieve a straighter ball path and improves the results of off-center hits (impacts at the heel or toe end).

[0455] By creating a putter-type golf club head from two parts of two different materials, it is possible to optimize the putter-type golf club head and improve the MOI while maintaining the desired overall weight of the golf club head. In some embodiments, the moment of inertia of the golf club head around the y-axis center of gravity is 3500 g·cm. 2 ~6500g·cm 2 It is between [values]. In another embodiment, the moment of inertia of the golf club head around the y-axis centroid is 3500 g·cm 2 ~4000g·cm 2 , 4000g·cm 2 ~4500g·cm 2 , 4500g·cm 2 ~5000g·cm 2 5000g·cm 2 ~5500g·cm 2 5500g·cm 2 ~6000g·cm 2 , or 6000g·cm 2 ~6500g·cm 2This can be between the above. The golf club head includes a 2% to 15% increase in MOI around the y-axis on a club head lacking a multi-material structure (i.e., a single material). In other embodiments, the golf club head has an increase of 2% to 5%, 5% to 10%, or 10% to 15% compared to a club head having a single material.

[0456] A putter-type golf club head having an upper and lower section made of two different materials increases the MOI around the y-axis center of gravity by at least 30% compared to a putter of the same volume, mass, and single-material construction (i.e., a steel putter or a putter milled from a single material, such as a single-material putter skin casting). In some embodiments, a putter-type golf club head having an upper and lower section made of two different materials increases the MOI around the y-axis center of gravity by at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least at least 80%, at least 85%, at least 90%, at least 95%, at least 95%, at least 100%, or at least 105% compared to a putter of the same volume, mass, and single-material construction.

[0457] The putter-type golf club head with the alignment aid 1544 shown in Figures 15A to 15D is visually pleasing and offers a visual advantage that creates repeatability in putting. The alignment aid 1544 helps the user consistently align the putter head properly with the golf ball. The alignment aid 1544 includes a ball outline mechanism 1580 that helps the viewer align the putter head outside the golf ball, and a center line 1576 that aligns the center of the golf ball with the putter head. Proper alignment of the putter head and golf ball allows the user to start the ball on the desired line. The putter head including the alignment aid 1544 is visually pleasing for creating a consistent putting stroke, while increasing perimeter weighting, MOI, and forgiveness.

[0458] VII. Examples a. Example 1 - Exemplary high MOI putter head An exemplary putter head 1300, which included a multi-material structure, was compared to a similar control putter head that lacked the multi-material structure. The exemplary putter head 1300, as shown in Figures 13A–13E, comprises an upper section 1304 formed from a low-density material and a lower section 1308 formed from a high-density material. The lower section 1308 further includes a sole plate containing toe mass 1345 and heel mass 1347 to increase perimeter weighting. The upper section 1300 further included a pocket 1372 that allowed for mass removal from the central part of the putter head 1300. The control putter head had similar mass, volume, and weight to the exemplary putter head 1300, but contained a single-material structure.

[0459] Tests were conducted to compare the moment of inertia around the y-axis (Iyy) between an exemplary putter head 1300 and a control putter head. The moment of inertia around the y-axis is a characteristic that determines the forgiveness of the putter head (i.e., its resistance to torsional motion after impact with the golf ball). The test results yielded an exemplary putter 1300 with a total mass of 363.2 grams and a total volume of 85.2 cc. The lower part 1308 contained a sole plate mass of 207.4 grams and a sole plate volume of 26.55 cc. The lower part 1308 contained 57.1% of the total mass of putter 1300, while containing 31.16% of the total volume of putter 1300.

[0460] The example putter 1300 weighs 4368 g·cm around the y-axis (Iyy). 2 The MOI included the following: The control putter head measured 3702 g·cm around the y-axis (Iyy). 2The MOI was found to be 10.78% higher than that of the control putter head. The results show that the exemplary putter head 1300 contained an MOI that was 10.78% higher than that of the control putter head. The exemplary putter head 1300 achieves the desired peripheral weighting to increase MOI and forgiveness while maintaining the desired mass and volume. The exemplary putter 1300 achieves high MOI with a multi-material structure on a putter head formed from a single material.

[0461] b. Example 2 - Exemplary high MOI putter head An exemplary putter head 1400, which included a multi-material structure, was compared to a similar control putter head that lacked the multi-material structure. The exemplary putter 1400 included an upper part 1404 formed from a low-density material and a lower part 1408 formed from a high-density material, as shown in Figures 14A–14D. The lower part 1408 further included a sole plate containing a toe mass 1446, a heel mass 1448, and a rear mass 1450 to increase perimeter weighting. The exemplary putter head 1400 further included a ball retrieval mechanism 1422 located on the sole 1442. The ball retrieval mechanism 1422 further increases perimeter weighting by removing material and mass from the central region of the putter head 1400. The control putter head included similar mass, volume, and weights to the exemplary putter head 1300, but included a single-material structure.

[0462] Tests were conducted to compare the moment of inertia around the y-axis (Iyy) between an exemplary putter head 1300 and a control putter head. The moment of inertia around the y-axis is a characteristic that determines the forgiveness of the putter head (i.e., its resistance to torsional motion after impact with the golf ball). The test results yielded an exemplary putter 1400 with a total mass of 360 grams and a total volume of 80.79 cc. The lower part 1408 contained a sole plate mass of 228 grams and a sole plate volume of 29.74 cc. The lower part 1408 contained 63% of the total mass of putter 1400, while containing 37% of the total volume of putter 1400.

[0463] The exemplary pattern 1400 had a MOI of 4710 g·cm around the y-axis (Iyy). 2 The control pattern head had a MOI of 4474 g·cm around the y-axis (Iyy). 2 The test results show that the exemplary pattern head 1400 had a 5.26% increase in MOI compared to the control pattern head. The exemplary pattern head 1400 achieves the desired peripheral weighting to increase MOI and tolerance while maintaining the desired mass and volume. The exemplary pattern 1400 achieves a high MOI with a multi-material structure on a pattern head formed from a single material.

[0464] c. Example 3 - Exemplary High MOI Pattern Head An exemplary pattern head 1500 including a multi-material structure was compared with a similar control pattern head that lacked the multi-material structure. The exemplary pattern head 1500 included an upper part 1504 formed from a low-density material and a lower part 1508 formed from a high-density material, as shown in FIGS. 15A - 15D. The lower part 1508 included a sole plate including a toe mass 1545 and a heel mass 1547 to increase peripheral weighting. The upper part 1504 further defined a central recess 1570 to enable mass removal from the central part of the pattern-type club head 1500. The control pattern head had a similar mass, volume, and weight as the exemplary pattern head 1500, but included a single-material structure.

[0465] A test was conducted to compare the moment of inertia around the y-axis (Iyy) between an exemplary putter head 1300 and a control putter head. The moment of inertia around the y-axis is a characteristic that determines the forgiveness of the putter head (i.e., its resistance to torsional motion after impact with the golf ball). As a result of this test, an exemplary putter-type club head 1500 was obtained with a total mass of 366.5 grams and a total volume of 87 cc. The lower part 1508 contained a sole plate mass of 205.7 grams and a sole plate volume of 26.2 cc. The lower part 1508 contained 56.1% of the total mass of the putter-type club head 1500, while it contained 30.1% of the total volume of the putter-type club head 1500.

[0466] An example putter-type club head 1500 weighs 4416 g·cm around the y-axis (Iyy). 2 The MOI included the following: The control putter head had a MOI of 4324 g·cm around the y-axis (Iyy). 2 The MOI was as follows: Test results showed that the exemplary putter head had a 2.12% increase in MOI compared to the control putter head. The exemplary putter head 1500 achieves the desired peripheral weighting to increase MOI and forgiveness while maintaining the desired mass and volume. The exemplary putter head 1500 achieves high MOI with a multi-material structure on a putter head formed from a single material. The exemplary putter head 1500 further included a ball outline alignment aid to improve putting consistency while being pleasing to the eye during repeated ball impacts.

[0467] d. Example 4 - Putter Alignment Assist Test Further described herein is a player test comparing two putter-style clubheads with different alignment aids. The clubheads were mallet-style clubheads with similar shapes but included different alignment aid styles. The results compared the impact of different alignment aid types on player satisfaction and performance.

[0468] The first putter-type club head (hereinafter referred to as the "comparison club head") included an alignment aid (hereinafter referred to as the "comparison aid") similar to that of club head 1200, as shown in Figure 12A. The comparison aid was located on the crown and included three parallel lines extending from the striking face to the rear end. The center line was located behind the center point of the striking face, and the remaining lines were located on the heel and toe sides of the center line. The three parallel lines were approximately the width of a golf ball (i.e., 1.68 inches). The parallel lines were a different color from the color of the comparison club head. The comparison aid further included several grooves located between the parallel lines.

[0469] The second putter-type club head (hereinafter referred to as the "exemplary club head") included an alignment aid (hereinafter referred to as the "exemplary aid"), similar to the alignment aid 1544 associated with club head 1500, as shown in Figure 15D. The exemplary club head defined a central recess extending from the striking face to the rear end. The exemplary aid included a ball outline mechanism that outlined the periphery of the central recess. The ball outline mechanism included two arcuate sections, one arcuate near the striking face and the other arcuate near the rear end. The arcuate sections were connected by a series of parallel lines to form a continuous periphery around the central recess. The ball outline mechanism was approximately the same width as a golf ball and resembled an elliptical golf ball shape due to the arcuate sections. The ball outline mechanism included a different color from the exemplary club head. The exemplary aid was positioned within the central recess and further included a centerline extending along the length of the central recess. The center line was positioned further behind the center point of the hitting face.

[0470] A player test was conducted to compare the performance of the alignment aids between an exemplary aid and a control aid. The player test included 30 players who participated in the study, comparing their experience with the exemplary aid with a ball shaping mechanism and the control aid without a ball shaping mechanism. Players tested each club head under conditions where the shaft length and loft angle were similar to those of the putter club head. Furthermore, the player test was conducted on a typical putting surface. The test involved striking the entire putting surface with a golf ball using both the control and exemplary putter heads.

[0471] After the test, participants evaluated the club head's performance and satisfaction based on five parameters. These parameters included the appearance of the alignment aid, the performance of the alignment aid, the overall feel of the club head, accuracy, and comfort at address. Based on these parameters, the club head was assigned a rating from 1 to 5. A rating of 1 represented the lowest level of satisfaction, with the club head meeting only one parameter. A rating of 5 represented the highest level of satisfaction, with the club head meeting all five parameters. A rating of 4 represented a high level of satisfaction, with the club head meeting three or more parameters. [Table 1]

[0472] Table 1 above shows the number of participants who gave each sample club head a "good" rating, with a "good" rating being a score of 4 or 5. The example club heads were rated higher than the control club heads. The control club heads received a "good" rating from 46.4% of players, while the example club heads received a "good" rating from 68.9% of players.

[0473] The test results showed that the exemplary aid met more parameters than the control aid (e.g., appearance of the alignment aid, performance of the alignment aid, overall clubhead feel, accuracy, and comfort at address). Participants in the player test felt that the exemplary putter head was superior to the control putter head. The exemplary aid offers advantages over the control aid. The exemplary aid included multiple components, each contributing to the function of the alignment aid. The ball outline mechanism defined a rectangle generally resembling a golf ball, helping viewers visualize the outline of a golf ball's side. The center line helped viewers find the center of the clubhead. Furthermore, the exemplary aid utilized a central recess where the recessed wall disappeared when the clubhead was aligned. The exemplary putter head, including the exemplary aid, provided improved player performance and satisfaction while including a high MOI.

[0474] The rules of golf are changed from time to time (e.g., the United States Golf Association (USGA), the United Kingdom). New rules are applied by golf standards organizations and / or governing bodies such as the Golf Association (R&A). Because these rules may be used, or old rules may be abolished or changed, The golf equipment relating to the apparatus, methods, and products described in the specification is for golf at any specific time. The apparatus, methods and Golf equipment related to the product is published and sold as conforming or non-conforming golf equipment. and / or may be sold. The apparatus, methods and products described herein are subject to this rule. It is not restricted.

[0475] The above examples are putter-type golf clubs, apparatus, methods, and products described herein. It may also be described in relation to the product. On the other hand, the apparatus, method and product described herein are for Atka mackerel. - Other types of sports such as sticks, tennis rackets, fishing rods, ski poles, etc. It may also be applicable to supplies.

[0476] Furthermore, the embodiments and limitations described herein are subject to (1) Claim (2) Under the doctrine of equivalents, the table in the claim is not explicitly asserted in the scope of the claim. If the current elements and / or limitations are equivalent or potentially equivalent, they shall be made available to the public under the principle of openness. It is not something that can be done.

[0477] The replacement of one or more claimed elements constitutes reconstruction, not repair. Furthermore, the benefits, other advantages, and solutions to problems have been described with respect to specific embodiments. Any elements or components that may give rise to or make more prominent the benefits, advantages, solutions to problems, and the benefits, advantages, solutions, etc., should not be construed as material, essential, or essential functions or elements of any part or all of the claims.

[0478] Clause 1 A putter-type golf club head comprising an upper and a lower part, wherein the upper part is made of a first material having a first density, and the lower part is made of a second material having a second density, the first density being less than the second density, the lower part comprising a front peripheral portion, a toe peripheral portion, a heel peripheral portion, and a rear peripheral portion, the lower part further comprising an opening bounded by the front peripheral portion, the toe peripheral portion, the heel peripheral portion, and the rear peripheral portion, the upper part comprising a heel end, a toe end, a striking face, a rear wall, a back edge, a crown, and a bottom surface, wherein the toe end is opposite to the heel end, the back edge is opposite to the striking face, the crown extends from the striking face beyond at least a portion of the rear wall to the back edge, and the bottom surface extends from the striking face to the back edge A putter-type golf club head, located on the opposite side of the clubhead, with the upper part fixed to the lower part, the upper part being further from the ground plane than the lower part, the heel end overlapping at least a portion of the heel-side periphery, the toe end overlapping at least a portion of the toe-side periphery, the striking face overlapping at least a portion of the front periphery, the crown extending from the striking face to the rear periphery, the lower part and the upper part joining to form the sole, the sole in contact with the ground plane when the golf club head is in the address position, the striking face in contact with the loft plane, a loft angle formed between the loft plane and the ground plane, the lower part constituting less than 30% of the volume of the golf club head, and the lower part constituting more than 50% of the mass of the golf club head.

[0479] Clause 2 The putter-type golf club head according to Clause 1, further comprising: a toe mass at the joint between the toe-side peripheral portion and the rear peripheral portion; a heel mass at the joint between the heel-side peripheral portion and the rear peripheral portion; a rear mass located on the rear peripheral portion and equidistant from the toe-side peripheral portion and the heel-side peripheral portion; and a front mass located on the front peripheral portion and equidistant from the toe-side peripheral portion and the heel-side peripheral portion.

[0480] Clause 3 The putter-type golf club head according to Clause 2, wherein the toe mass, heel mass, rear mass, and front mass are integral with the lower part and extend from the lower part toward the upper part away from the ground plane.

[0481] Clause 4 The putter-type golf club head as described in Clause 1, wherein the upper crown further comprises a toe-end mid-rail, a heel-end mid-rail, a toe-end cap, and a heel-end cap.

[0482] Clause 5 The putter-type golf club head according to Clause 4, wherein the toe end cap is configured to fit with the toe mass, and the heel end cap is configured to fit with the heel mass.

[0483] Clause 6 The putter-type golf club head ...

Claims

1. A putter-type golf club head, It comprises a toe end, a heel end, a striking face, a rear end, a crown, a sole, an upper part, and a lower part. The upper part comprises a front portion and a rear extension, the front portion comprises the striking face, and the rear extension extends rearward from the front portion toward the rear end. The upper part defines a central recess that is recessed into the upper part via a recessed floor and a peripheral recessed wall, and the peripheral recessed wall completely surrounds the periphery of the recessed floor. The aforementioned upper part further includes an alignment assist section. The alignment assist unit is, A ball shaping mechanism surrounding the central recess and comprising one or more arc-shaped portions and a set of parallel lines, wherein the one or more arc-shaped portions are located near the striking face or the rear end, the set of parallel lines extends from the striking face to the rear end, and the ball shaping mechanism comprises a first color, and the ball shaping mechanism comprises, A center line located on the recessed floor, the center line is positioned within the ball outer shape mechanism, and the center line has a second color, the center line and It comprises a plurality of grooves that are recessed into the recessed floor on both sides of the center line, The lower part comprises a central part, a toe mass, and a heel mass. The lower part is configured to receive the upper part such that the rear extension is located above the central part between the toe mass and the heel mass. The upper part comprises a first material having a first density, and the lower part comprises a second material having a second density, wherein the first density is less than the second density. A putter-shaped golf club head.

2. A putter-type golf club head according to claim 1, having a loft angle of less than 7 degrees.

3. The one or more arc-shaped portions include a first arc-shaped portion near the striking face and a second arc-shaped portion near the rear end. The set of parallel lines connects the first and second arc-shaped sections, defining a continuous peripheral area around the central recess. The aforementioned ball outer shape mechanism has an oval shape, A putter-type golf club head according to claim 1 or 2.

4. The one or more curved portions include a single curved portion near the striking face, The set of parallel lines extends from the single arc-shaped portion toward the rear end, defining a discontinuous peripheral portion around the central recess. The ball outer shape mechanism has a U shape. A putter-type golf club head according to claim 1 or 2.

5. The putter-type golf club head according to any one of claims 1 to 4, wherein the ball outer shape mechanism is recessed into the upper part and defines a channel.

6. The putter-type golf club head according to any one of claims 1 to 4, wherein the ball outer shape mechanism protrudes outward from the upper part.

7. The aforementioned ball shape mechanism defines a width measured in the direction from the heel end to the toe end. The putter-type golf club head according to any one of claims 1 to 6, wherein the width of the ball outer shape mechanism is approximately 1.78 inches.

8. The putter-type golf club head according to any one of claims 1 to 7, wherein the first material and the second material are materials selected from the group consisting of 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, and ADC-12.

9. A putter-type golf club head, It comprises a toe end, a heel end, a striking face, a rear end, a crown, a sole, an upper part, and a lower part. The upper part comprises a front portion and a rear extension, the front portion comprises the striking face, and the rear extension extends rearward from the front portion toward the rear end. The upper part defines a central recess that is recessed into the upper part via a recessed floor and a peripheral recessed wall, and the peripheral recessed wall completely surrounds the periphery of the recessed floor. The aforementioned upper part further includes an alignment assist section. The alignment assist unit is, A ball shaping mechanism surrounding the central recess and comprising one or more arc-shaped portions and a set of parallel lines, wherein the one or more arc-shaped portions are located near the striking face or the rear end, the set of parallel lines extends from the striking face to the rear end, and the ball shaping mechanism comprises a first color, and the ball shaping mechanism comprises, A center line located on the recessed floor, the center line is positioned within the ball outer shape mechanism, and the center line has a second color, the center line and It comprises a plurality of grooves that are recessed into the recessed floor on both sides of the center line, The lower part comprises a central part, a toe mass, and a heel mass. The lower part is configured to receive the upper part such that the rear extension is located above the central part between the toe mass and the heel mass. The upper part comprises a first material having a first density, and the lower part comprises a second material having a second density, wherein the first density is less than the second density. The aforementioned putter-type golf club head further comprises volume and mass, The aforementioned lower portion constitutes less than 35% of the volume of the putter-type golf club head. The aforementioned lower portion constitutes more than 50% of the mass of the putter-type golf club head. A putter-shaped golf club head.

10. The one or more arc-shaped portions include a first arc-shaped portion near the striking face and a second arc-shaped portion near the rear end. The set of parallel lines connects the first and second arc-shaped sections, defining a continuous peripheral area around the central recess. The aforementioned ball outer shape mechanism has an oval shape, The putter-type golf club head according to claim 9.

11. The one or more curved portions include a single curved portion near the striking face, The set of parallel lines extends from the single arc-shaped portion toward the rear end, defining a discontinuous peripheral portion around the central recess. The ball outer shape mechanism has a U shape. The putter-type golf club head according to claim 9.

12. The putter-type golf club head according to any one of claims 9 to 11, wherein the ball outer shape mechanism is recessed into the upper part and defines a channel.

13. The putter-type golf club head according to any one of claims 9 to 11, wherein the ball outer shape mechanism protrudes outward from the upper part.

14. The aforementioned ball shape mechanism defines a width measured in the direction from the heel end to the toe end. The width of the ball outer shape mechanism is approximately 1.78 inches. A putter-type golf club head according to any one of claims 9 to 13.

15. The putter-type golf club head according to any one of claims 9 to 14, wherein the first material and the second material are materials selected from the group consisting of 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, and ADC-12.

Images