Multi-Component Putter

Abstract

To develop a putter which has weighting in the surroundings without adding a complicated structure such as a weight port and has an ideal weight for balanced putting.SOLUTION: An embodiment of a putter type golf club head includes an upper portion and a lower portion, the upper portion is made from a first material with first density, the lower part is made from a second material having second density, and the first density is smaller than the second density. The upper part is provided with a toe end, a heel end part, a hitting face, a rear wall, a back edge, a crown, and a lower surface; the lower portion is provided with a front peripheral part, a rear peripheral part, a sole, a toe side wing, and a heel side wing. The lower portion is further provided with a front toe mass, and a front heel mass. The front tow mass and the front heel mass are configured to engage a first cavity and a second cavity.SELECTED DRAWING: Figure 9A

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from U.S. Provisional Patent No. 62 / 739,747, filed October 1, 2018, the entire contents of which are incorporated herein by reference in their entirety. [Technical field]

[0002] The present disclosure relates generally to golf clubs, and more particularly, to multi-component putter-type golf club heads. [Background technology]

[0003] Many putter-type golf club heads use weight distribution devices to change the center of gravity or increase the moment of inertia (MOI) of the golf club head. Common weight distribution devices include removable weight ports in the heel and toe regions of the sole, weighted face plate inserts, inserts for the back of a portion of the face, and attachments for the periphery of the toe and heel regions. In particular, putter-type golf club heads often use weight ports in the heel and toe regions. The weight ports can be removably attached by fasteners or permanently attached by various epoxies, adhesives, or machining methods. The use of weight ports in the heel and toe regions increases the MOI of the putter head, which results in a straighter ball path after impact.

[0004] Although these weight ports in the heel and toe regions increase the MOI, they also increase the weight of the golf club head, making the golf club head heavier than the ideal weight for a putter. Furthermore, attaching weight ports to a golf club putter head requires cavities or recesses in which to place these weight ports in the putter head during manufacturing, thereby increasing the cost of the putter head. In addition, the weight ports may create vibrations within the cavity or recesses during impact when the golf club head contacts the golf ball. These cavities and recesses also change the sound of the club head, creating a hollow sound within the club head. There is a need in the art to develop a putter with perimeter weighting and ideal weight for balanced putting without adding complex structures such as weight ports. [Brief description of the drawings]

[0005] [Figure 1A] FIG. 2 is an exploded view of a blade putter-type golf club head.

[0006] [Figure 1B] FIG. 1B is an isometric view of the blade putter-style golf club head of FIG. 1A.

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

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

[0009] [Figure 2B] FIG. 2B is an isometric view of the blade putter-style golf club head of FIG. 2A.

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

[0011] [Figure 3A] 1 shows an exploded view of a crescent putter type golf club head.

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

[0013] [Figure 3C] 3B shows a side view of the crescent putter golf club head of FIG. 3A.

[0014] [Figure 4A] 1 shows an exploded view of a semicircular putter-type golf club head.

[0015] [Figure 4B] FIG. 4B is an isometric view of the semicircular putter-style golf club head of FIG. 4A.

[0016] [Figure 4C] FIG. 4B is a side view of the semicircular putter-type golf club head of FIG. 4A.

[0017] [Figure 5A] 1 shows an exploded view of another semi-circular putter-type golf club head.

[0018] [Figure 5B] FIG. 5B is an isometric view of the semicircular putter-style golf club head of FIG. 5A.

[0019] [Figure 5C] FIG. 5B is a side view of the semicircular putter-type golf club head of FIG. 5A.

[0020] [Figure 6A] 1 shows an exploded view of a wing putter type golf club head.

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

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

[0023] [Figure 7A] 1 shows an exploded view of a spade putter type golf club head.

[0024] [Figure 7B] 7B shows an isometric view of the spade putter style golf club head of FIG. 7A.

[0025] [Figure 7C] 7B shows a side view of the spade putter type golf club head of FIG. 7A.

[0026] [Figure 8A] FIG. 1 is an exploded view of a T-shaped putter type golf club head having a perimeter span.

[0027] [Figure 8B] FIG. 8B is an isometric view of a T-shaped putter type golf club head having the perimeter span of FIG. 8A.

[0028] [Figure 8C] FIG. 8B is a side view of a T-shaped putter type golf club head having the perimeter span of FIG. 8A.

[0029] [Figure 9A] FIG. 2 is an exploded view of a dual rail putter type golf club head.

[0030] [Figure 9B] FIG. 9B is an isometric view of the dual rail putter style golf club head of FIG. 9A.

[0031] [Figure 9C] FIG. 9B is a side view of the dual rail putter style golf club head of FIG. 9A.

[0032] [Figure 10A] 1 shows an exploded view of a circular putter-type golf club head.

[0033] [Figure 10B] FIG. 10B is an isometric view of the circular putter-style golf club head of FIG. 10A.

[0034] [Figure 10C] FIG. 10B is a side view of the circular putter-type golf club head of FIG. 10A.

[0035] [Figure 11A] 1 shows an exploded view of a putter-type golf club head having at least one striking face insert.

[0036] [Figure 11B] 1 illustrates an exploded view of another putter-type golf club head having at least one striking face insert.

[0037] Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] I. Putter Golf Club Head Described herein is a two-part putter having an upper portion made of a first material, such as a low density metal (i.e., but not limited to, aluminum), and a lower portion made of a second material, such as a high density metal (i.e., but not limited to, steel). The upper portion has a crown that extends from the striking face to the back edge. The upper portion is affixed to the lower portion and is further from the ground plane than the lower portion. The lower portion, in most embodiments, is less than 35% of the total real volume of the putter head, but more than 45% of the mass. The lower portion provides the perimeter structure and sole. This combination of the perimeter structure and high density lower portion provides an increase in MOI of at least 30% over a putter having the same volume, mass, and single material construction (i.e., a single material putter milled such as a steel putter or a single material putter investment casting).

[0039] Terms such as "first," "second," "third," and "fourth" in the detailed description and claims, when present, are used to distinguish between similar elements and are not necessarily used to describe a particular sequential or chronological order. It should be understood that such terms used are interchangeable under appropriate circumstances, and that the embodiments described herein are capable of, for example, sequences of operation other than those illustrated or otherwise described herein. Moreover, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that includes a list of elements is not necessarily limited to those elements, but can include other elements not expressly recited or inherent in such process, method, system, article, device, or apparatus.

[0040] The terms "left," "right," "front," "rear," "upper," "lower," "upper," "lower," "upper," "lower," and the like in the description and claims are used for explanatory purposes and are not necessarily intended to describe permanent relative positions. Terms so used are interchangeable under appropriate circumstances. Thus, it is to be understood that the embodiments of the apparatus, methods, and / or articles of manufacture described herein can operate in orientations other than those shown or otherwise described herein, for example.

[0041] Before any embodiment of the present disclosure is described in detail, it is to be understood that the disclosure is not limited in its application to the details or the construction and arrangement of components as set forth in the following description or illustrated in the drawings. The present disclosure is capable of supporting other embodiments and may be practiced or carried out in various ways.

[0042] In many embodiments, the golf club head can include a putter-type golf club head (such as putter-type golf club heads 100, 200, 300, 400, etc.). Figures 1-12B show several embodiments of putter-type golf club heads having upper and lower portions made of separate different materials and joined together. The putter-type golf club head can 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.

[0043] In many embodiments, the 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 can be 0-5 degrees, 0-6 degrees, 0-7 degrees, or 0-8 degrees. For example, the loft angle of the club head can 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 can be 0 degrees, 1 degree, 2 degrees, 3 degrees, 4 degrees, 5 degrees, 6 degrees, 7 degrees, 8 degrees, 9 degrees, or 10 degrees.

[0044] The putter-type golf club head includes an upper portion and a lower portion. The golf club head may include a toe end and a heel end opposite the toe end. The putter-type golf club head may include a striking face. The putter-type golf club head may include a rear wall opposite the striking face. Additionally, the putter-type golf club head may include an alignment feature. Additionally, the putter-type golf club head may include a hosel attached to the heel end of the golf 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 integrally formed with the upper portion of the putter-type golf club head. The hosel may be integrally formed with the lower portion of the putter-type golf club head.

[0045] The top portion is made of a first material. The bottom portion is made of a 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 first density is not the same as the second density.

[0046] 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, 384 grams.

[0047] In many embodiments, the putter-type golf club head can be configured with a club head volume ranging from 25cc to 125cc. In some embodiments, the club head volume can 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 can be in the range of 40cc to 110cc. In some embodiments, the club head volume may be greater than 25 cc, greater than 50 cc, greater than 75 cc, or greater than 100 cc.

[0048] In some embodiments, the putter-type golf club head can include a striking face made of a first material. In other embodiments, the striking face can be made of a second material. In these embodiments, the striking face material can be any of the following materials or combinations thereof: 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 to 8.05 g / cc), tungsten (19.25 g / cc), aluminum (2.70 g / cc), aluminum alloy (2.64 g / cc to 2.81 g / cc), ADC-12 (2.75 g / cc). In some embodiments, the striking face can be integrally formed on the upper portion. In other embodiments, the striking face can be integrally formed on the lower portion. The striking face can be integrally formed on the club head by co-molding, injection molding, casting, additive manufacturing, or other molding processes.

[0049] 11A and 11B, in some embodiments, the putter-type golf club head can include a striking face insert. In these embodiments, the striking face is formed separately before being bonded to the club head. The side of the striking face insert that contacts the club head can be geometry complementary to the geometry of the corresponding portion of the club head that contacts the striking face. In some embodiments, the striking face insert can be made of a first material or a second material. In other embodiments, the striking face insert can be made of a third material. In some implementations, the striking face insert can be integrally formed with the upper or lower portion. In other embodiments, the striking face insert can be formed separately from both the upper and lower portions.

[0050] The striking face can be secured to the club head by being integrally formed with a portion of the club head or by a fastening means. In some embodiments, the striking face is secured to the upper portion. In these embodiments, the upper portion can include an insert cavity. The upper insert cavity functions to receive the striking face insert. Further, in these embodiments, when the insert is secured to the upper portion, the upper portion surrounds and mates with the insert cavity. In other embodiments, the striking face is secured to the lower portion. In these embodiments, the lower portion can include an insert cavity. The lower insert cavity functions to receive the striking face insert. Further, in these embodiments, when the insert is secured to the lower portion, the lower portion surrounds and mates with the insert cavity. The striking face can be secured by an adhesive, such as a glue, a Very High Bond (VHB®) tape, an epoxy, or another adhesive. Alternatively or additionally, the striking face can be secured by welding, soldering, screws, rivets, pins, a mechanical interlocking structure, or another fastening method.

[0051] The striking face insert of these embodiments may be constructed of any one or laminate combination of the following materials: 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 suitable materials. PEBAX® is a polyether block amide, which is a thermoplastic elastomer made from soft polyethers and hard polyamides. The hard polyamides 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% by weight) and nylon 12. PEBAX® 6333 (Arkema, Paris France) contains nylon 11. In some embodiments, the face insert can include a material such as steel, steel alloy, tungsten, tungsten alloy, aluminum, aluminum alloy, titanium, titanium alloy, vanadium, vanadium alloy, chromium, chromium alloy, cobalt, cobalt alloy, nickel, nickel alloy, other metals, other metal alloys, composite polymeric materials, or any combination thereof.

[0052] PEBAX® can include a volume percentage of polyether. In some embodiments, PEBAX® can include 0%-10%, 10%-20%, 15%-30%, 20%-30%, 30%-40%, 30%-50%, 30%-60%, 40%-50%, 40%-60%, 50%-60%, or 60%-70% polyether by volume. For example, PEBAX® can include 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% polyether by volume. In some embodiments, PEBAX® can contain 0%-10%, 10%-20%, 15%-30%, 20%-30%, 30%-40%, 40%-50%, 40%-60%, 50%-60%, or 60%-70% polyamide by volume. For example, PEBAX® can contain 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% polyamide by volume. As the percentage of polyether increases, the hardness of PEBAX® decreases. As the percentage of polyamide increases, the hardness of PEBAX® 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.

[0053] In many embodiments, PEBAX® can include a hardness ranging from Shore D 25D to Shore D 75D. In some embodiments, the hardness of PEBAX can range from Shore D 25D to Shore D 35D, Shore D 35D to Shore D 45D, Shore D 36D to Shore D 44D, Shore D 38D to Shore D 42D, Shore D 45D to Shore D 55D, Shore D 55D to Shore D 65D, Shore D 56D to Shore D 64D, Shore D 60D to Shore D 65D, or Shore D 65D to Shore D 75D. For example, the hardness of PEBAX can be Shore D 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70.

[0054] In many embodiments, PEBAX® 4033 (Arkema, Paris France) can include a lower hardness than PEBAX® 6333 (Arkema, Paris France). In many embodiments, PEBAX® 4033 (Arkema, Paris France) can include a hardness range of Shore 35D to Shore 55D. In some embodiments, PEBAX® 4033 (Arkema, Paris France) can include a hardness range of Shore 38D to Shore 42D, or Shore 39D to Shore 41D. For example, PEBAX® 4033 (Arkema, Paris France) can include a Shore D hardness of 40. In many embodiments, PEBAX® 6333 (Arkema, Paris France) can include a hardness range of Shore 50D to Shore 75D. In some embodiments, PEBAX® 6333 (Arkema, Paris France) can include a hardness range 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.

[0055] In some embodiments, the face insert can include a two-component system. The two-component system can include a ball striking face plate and a face insert base. The ball striking face plate of the face insert can include a first insert material. The face insert base of the face insert can include a second insert material. In many embodiments, the first insert material of the ball striking face plate and the second material of the face insert base can be different. In some embodiments, the first insert material of the ball striking face plate and the second insert material of the face insert base can be similar. In many embodiments, the first insert material of the ball striking face plate can include a polymer type material. In some embodiments, the first insert material of the ball striking face plate can include a metallic material. In many embodiments, the second insert material of the face insert base can include a polymer type material.

[0056] The first insert material can include a metal such as steel, a steel alloy, tungsten, a tungsten alloy, aluminum, an aluminum alloy, titanium, a titanium alloy, vanadium, a vanadium alloy, chromium, a chromium alloy, cobalt, a cobalt alloy, nickel, a nickel alloy, other metals, other metal alloys, composite polymeric materials, or any combination thereof.

[0057] The first insert material or the second insert material can include a polymer type material. The polymer type material can include polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, or any other polymer type material. In many embodiments, the face insert can include PEBAX®. More specifically, PEBAX® is a polyether block amide, which is a thermoplastic elastomer made from flexible polyether and hard polyamide. The hard polyamide can include nylon. PEBAX® can include different compounds corresponding to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, PEBAX® can include PEBAX® 4033 (Arkema, Paris France) or PEBAX® 6333 (Arkema, Paris France). PEBAX® 4033 (Arkema, Paris France) includes tetramethylene oxide (53% by weight) and nylon 12. PEBAX® 6333 (Arkema, Paris France) comprises nylon 11. The first and second insert materials may comprise the same polyether percentages, polyamide percentages, or Shore D hardness values ​​as described above.

[0058] The ball striking face plate of the face insert can have a thickness. In many embodiments, the ball striking face plate can have a thickness in the range of 0.015 to 0.115 inches. In some embodiments, the ball striking face plate can have a thickness 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 face plate 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 face plate 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 or more. In some embodiments, the thickness of the ball striking face plate 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 or less. For example, the thickness of the ball striking face plate 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.

[0059] In other embodiments, the thickness of the ball striking face plate may range from 0.115 to 0.40 inches. In some embodiments, the thickness of the ball striking face plate may range from 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 face plate may 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 face plate may be 0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 or more. In some embodiments, the thickness of the ball striking face plate may be less than or equal to 0.15 inches, 0.20 inches, 0.25 inches, 0.30 inches, 0.35 inches, or 0.40 inches. For example, the ball striking face plate may have a thickness of 0.15 inches, 0.20 inches, 0.25 inches, 0.30 inches, 0.35 inches, or 0.40 inches.

[0060] The face insert base of the face insert can have a thickness. In many embodiments, the thickness of the face insert base can range from 0.05 to 0.20 inches. In some embodiments, the thickness of the face insert base can range from 0.05 to 0.10 inches, or 0.10 to 0.20 inches. In some embodiments, the thickness of the face insert base can 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 can 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 can 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 can be 0.05 inches, 0.10 inches, 0.15 inches, or 0.20 inches.

[0061] In other embodiments, the thickness of the face insert base can range from 0.20 to 0.80 inches. In some embodiments, the thickness of the face insert base can range from 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 can range from 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 of the face insert 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 of the face insert 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 or more. In some embodiments, the face insert base of the face insert 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 or less. For example, the thickness of the face insert base 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.

[0062] The face insert can be formed by many different processes. The different molding processes include injection molding, casting, blow molding, compression molding, co-molding, 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. Additionally, the face insert can have any combination of the hardness, volume, thickness, and molding process described above.

[0063] In many embodiments, the upper portion of the putter-type golf club head having a first material includes a first density in the range of 1.0 g / cc to 6.0 g / cc. The first density can be in the range of 2.0 g / cc to 5.0 g / cc. In some embodiments, the first density can 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 -5.5 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 can 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 can 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, 6.0 g / cc.

[0064] In many embodiments, the lower portion of the putter-type golf club head has a second material. The second material can include a density. The density is a second density relative to the first density of the first material in the upper portion. The second density of the second material in the lower portion 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 g / cc, 15.0-16.0 g / cc, 16.0-17.0 g / cc, 17.0-18.0 g / cc, 18.0-19.0 g / cc, 19.0-20.0 g / cc, 20.0-21.0 g / cc, 21.0-22.0 g / cc, 22.0-23.0 g / cc, 23.0-24.0 g / cc, 24.0-25.0 g / cc, 25.0-26.0 g / cc, 26.0-27.0 g / cc, 27.0-28.0 g / cc, 28.0-29.0 g / cc, 29.0-30.0 g / cc, 30.0-31.0 g / cc, 31.0-32.0 g / cc, 32.0-33.0 g / cc, 33.0-34.0 g / cc, 34.0-35.0 g / cc, 35.0-36.0 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 portion 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 portion can be at least two times the first density, at least three times the first density, at least four times the first density, or at least five times the first density. In some embodiments, the second density can be greater than 7.0 g / cc, greater than 9.0 g / cc, greater than 10.0 g / cc, greater than 11.0 g / cc, or greater than 12.0 g / cc.

[0065] The upper portion of the putter-type golf club having the first material may be made from any one or 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 golf club heads. In many embodiments, the upper portion is made of aluminum alloy or ADC-12.

[0066] The lower portion of the putter-type golf club having the second material may be made from any one or 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 to 8.05 g / cc), tungsten (19.25 g / cc), aluminum (2.70 g / cc), aluminum alloy (2.64 g / cc to 2.81 g / cc), ADC-12 (2.75 g / cc), or other metals suitable for making golf club heads. In many embodiments, the lower portion is made of 304 stainless steel, 8620 alloy steel, 17-4 stainless steel, or 1380 stainless steel. However, the lower portion and upper portion are not made of the same one or combination of materials.

[0067] Additionally, the upper and lower portions of the putter-type golf club head may be joined by any method or combination of welding, soldering, brazing, swedging, adhesives, epoxies, or mechanical fastening. In some embodiments, the upper and lower portions may be joined by adhesion with epoxies, polyurethanes, resins, hot melts, or any other adhesive.

[0068] (A. Advantages) The putter-type golf club head provides MOI, CG, feel, and weighting advantages over a putter-type golf club head having upper and lower parts with different densities and / or upper and lower parts without the use of 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 weight of the club head is shifted 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 raises the MOI of the club head about the y-axis (Iyy), thus preventing rotation about the y-axis and ensuring that the striking face is square to the golf ball during impact. The increase in MOI about the y-axis helps achieve a straighter ball path and improves the outcome of off-center strikes (impacts at the heel or toe ends).

[0069] By creating a putter-type golf club head from two portions of two different materials, the putter-type golf club head can be optimized to improve the MOI while keeping the golf club head at a desired total weight. In some embodiments, the moment of inertia of the golf club head about the y-axis center of gravity is between 3500g·cm2-6500g·in2. In other embodiments, the moment of inertia of the golf club head about the y-axis center of gravity can be between 3500g·cm2-4000g·cm2, 4000g·cm2-4500g·cm2, 4500g·cm2-5000g·cm2, 5000g·cm2-5500g·cm2, 5500g·cm2-6000g·cm2, or 6000g·cm2-6500g·cm2.

[0070] A putter-type golf club head having upper and lower portions of two different materials increases the MOI about the y-axis center of gravity by at least 30% over a putter having the same volume, mass, and single-material construction (i.e., a single-material milled putter such as a steel putter, or a single-material putter investment cast). In some embodiments, a putter-type golf club head having upper and lower portions of two different materials increases the MOI about 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 80%, at least 85%, at least 90%, at least 95%, at least 95%, at least 100%, or at least 105% over a putter having the same volume, mass, and single-material construction.

[0071] II. EMBODIMENTS a. BLADE EMBODIMENTS In one embodiment, the putter-type golf club head can be a blade-type putter head 100. With reference to FIGS. 1A and 1B, the blade-type putter head 100 has an upper portion 104 and a lower portion 108. The upper portion 104 is made from a first material having a first density and the lower portion 108 is made from a second material having a second density. The first density is less than the second density. The upper portion 104 and the lower portion 108 combine to create a balanced putter head 100 while maintaining a desired volume and mass.

[0072] The lower portion 108 includes a toe end 124, a heel end 128 opposite the toe end 124, a rear wall 132 opposite the front face 112, a rear portion 156, and a lower surface (not shown). The lower surface and the upper portion 104 form a sole 168. The rear wall 132 is opposite and generally parallel to the front face 112. The toe end 124 is opposite the heel end 128 and adjacent the striking face 112 and the rear portion 156. The rear portion 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 portion 156 is adjacent the sole. The lower surface extends from the heel end 128 to the toe end 124 and is adjacent the rear portion 156 and the front face 112.

[0073] Additionally, the toe end 124, the heel end 128, and the front surface 112 of the lower portion 108 form a recess 140 that extends inwardly from the front surface 112 toward the rear wall 132. The recess serves to receive the upper portion 104. In most embodiments, the recess 140 comprises a corresponding geometric shape that is similar or identical to the geometric shape of the upper portion 104. When the upper portion 104 is secured to the lower portion 108, the upper portion 104 surrounds and mates with the lower portion 108 to fit within the recess 140.

[0074] The lower portion 108 of the blade-type putter head 100 may further include an alignment feature 136. The alignment feature 136 may be any one or combination of the following: a line, a circle, a dashed line, a triangle, a channel, or any other suitable alignment feature 136. With reference to Figures 2A-2C, in some embodiments, the blade-type putter head 200 may include an alignment feature 236 on the upper portion 204 rather than the lower portion 208.

[0075] The upper portion 104 of the blade-type putter 100 head has a striking face 113 and an adhesive surface 115. The striking face 113 includes an upper edge 116 and a lower edge 121, with the upper edge 116 being farther away from a ground plane 172 than the lower edge 121. The ground plane 172 contacts the lower portion 108 when the putter head is in an address position to strike a golf ball. The upper edge 116 is adjacent to the striking face 113 and adhesive surface 115 and opposite the lower edge 121. In most embodiments, the striking face 113 and adhesive surface 115 are parallel, but in other embodiments, the striking face 113 and adhesive surface 115 are not parallel.

[0076] When the top 104 and bottom 108 are joined together, the adhesive surface 115 is secured in the recess 140 in the bottom 108. The striking face 113 of the top 104 and the front face 112 of the bottom align to form a striking face 120 that functions to strike a golf ball.

[0077] The lower edge 121 of the upper portion 104 and the underside of the lower portion 108 combine to form a sole 168. The sole 168 is perpendicular to a ground plane 172. The ground plane 172 is tangent to the sole 168 when the putter 100 is in the address position to strike 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.

[0078] 1C , in most embodiments, the sole 168 of the putter head 100 may be completely flat. In some embodiments, the sole 168 of the putter head 100 may have a slight arch in the direction from the heel 128 to the 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 the heel 128 to the 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.

[0079] 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 1212 and the upper edge 116 of the striking face 120, as well as equidistant from the heel end 128 and the 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. Additionally, a midplane 184 intersects the striking face center point 176 and is perpendicular to the loft plane 180. Additionally, a y-axis 188 intersects the striking face center point 176 and is perpendicular to the ground plane 172.

[0080] In some embodiments, when the lower portion 108 and upper portion 104 are joined, the upper edge 116 of the upper portion 104 can overlap at least a portion of the rear wall 132 of the lower portion 108 and project away from the striking face 120. Additionally, the lower edge 121 of the upper portion 104 can project away from the striking face 120 toward at least a portion of the lower surface of the lower portion 108, thereby forming part of the sole 168. In these embodiments, the rear wall 132 of the lower portion 108 does not form part of the sole 168.

[0081] The combination of a lower density first material upper portion 104 and a higher density second material lower portion 108 increases the MOI of the putter 100 over a putter with a single solid block construction. The two-part construction of the putter 100 (upper portion 104 and lower portion 108) moves the denser material toward the heel 128 and toe 124 while placing the lighter material (upper portion 104) near the center, thereby increasing the MOI of the putter 100, with more mass further away from the center of gravity. The denser material at the lower portion helps increase the MOI of the putter-type golf club head by shifting the weight of the putter head 100 toward the outer portion of the putter-type golf club head. A single material putter does not allow the high density material to be allocated to the periphery. In some embodiments, a putter-type golf club head 100 with two different material upper portions 104 and lower portions 108 increases the MOI around the y-axis center of gravity by at least 15% over a putter with the same volume, mass, and single material construction.

[0082] (b. Crescent-Shaped Embodiment) In one embodiment, the putter-type golf club head can be a crescent-shaped putter head 300. Referring to FIGS. 3A-3C, the crescent-shaped putter head 300 has an upper portion 304 and a lower portion 308. The upper portion 304 is made from a first material having a first density, and the lower portion 308 is made from a second material having a second density. The first density is less than the second density. The upper portion 304 and the lower portion 308 combine to create a balanced putter head 300 while maintaining a desired volume and mass. The high density lower portion 308 and the low density upper portion 304 place more mass near the perimeter of the putter head 300. Thus, the MOI and stability are increased relative to a putter having the same volume, mass, and single material construction.

[0083] As discussed above, the lower portion 308 is constructed from a high density material (i.e., the second material). The lower portion 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 lower surface (not shown). The lower surface and the upper portion 304 form a sole 368. The toe end 312 is opposite the heel end 316. The toe end 312 and heel end 316 of the lower portion 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 and generally parallel to the striking face 320. The lower portion further includes a heel perimeter 360 , a toe perimeter 356 , a front edge 348 , and an upper edge 312 .

[0084] The front edge 348 is adjacent to a toe side perimeter 356 and a heel side perimeter 360, and is opposite the rear perimeter 352. The toe side perimeter 356 is adjacent to the front edge 348 and the rear perimeter 352, and is opposite 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 opposite the toe side perimeter 356.

[0085] 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° angle) 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°-180°) can be formed at the junction of the toe side perimeter 356 and the front edge 348. Further, in most embodiments, the heel side perimeter 360 extends perpendicularly from the front edge 348 such that a right angle (90° angle) 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°-180°) can be formed at the junction of the heel side perimeter 360 and the front edge 348.

[0086] 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 moves the majority of the putter's volume and mass to the end of the lower portion 308. Although the opening 364 can include any shape, in one embodiment, the opening 364 is approximately rectangular. In other embodiments, the opening 364 can be circular, curvilinear, triangular, trapezoidal, parabolic, golf ball shaped, square, or any other desired geometric shape.

[0087] The top 304 of the putter head 300 includes a crown 342, a front edge 370, and a back edge 334. The crown 342 extends away from the front edge 370 to the back edge 334 of the top 304. With the crown 342 spanning from the front edge 348 to the back edge 334, the underside is opposite.

[0088] 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 putter head 300 is approximately crescent shaped, and thus 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 curvilinear length of the rear perimeter 352 can be between 4.5 inches and 6.5 inches. In some embodiments, the curvilinear length of the rear perimeter can be between 4.5 inches and 4.75 inches, 4.75 inches and 5.0 inches, 5.0 inches and 5.25 inches, 5.25 inches and 5.5 inches, 5.5 inches and 5.75 inches, 5.75 inches and 6.0 inches, 6.0 inches and 6.25 inches, or 6.25 inches and 6.5 inches.

[0089] When the upper and lower portions 304, 308 are joined, the crown 342 extends between the striking face 320 to the rear perimeter 352. In most embodiments, the crown 342 spans approximately the inner 25% of the overall club head 300 width from the toe perimeter 356 and approximately the inner 25% of the overall club head 300 width from the heel perimeter 360. In other embodiments, the crown 342 may span the entire width of the entire club head 300 from the heel 316 to the toe 312, either continuously or discontinuously. In some embodiments, the crown 342 may span less than 90% of the overall width of the club head 300, less than 80% of the overall width of the club head 300, less than 70% of the overall width of the club head 300, less than 60% of the overall width of the club head 300, less than 50% of the overall width of the club head 300, less than 40% of the overall width of the club head 300, or less than 30% of the overall width of the club head 300. Additionally, in some embodiments, the crown 342 can be substantially flat from the striking face 320 to the back edge 334, or can rise from the striking face 320 to the back edge 334. In most embodiments, the rise or fall of the crown 342 can be a linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0090] 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 the rear wall 328 and is approximately perpendicular to the striking face. The alignment trough 355 is bounded by the back edge 334, the rear wall 332, and the crown 342 on the heel end 316 and on the toe end 312. In most embodiments, the alignment trough provides the viewer with a visual alignment field approximately equal to and extending the width of a golf ball (approximately 4.27 cm).

[0091] Additionally, the top 304 of the putter head 300 may include one or more alignment features 344 on the crown 342. The alignment features 344 may be any one or combination of a line, a series of lines, a milled trough, a circle, a dashed line, a triangle, a channel, or any other desired alignment features 344. The alignment features 344 may be evenly spaced across the entire crown 342, a portion of the crown 342, or on the alignment troughs 355. The alignment features 344 extending along the alignment troughs 355 function to provide the viewer with a visual alignment field that extends the width of a 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 a golf ball using these alignment features 344 along the crown 342 and / or alignment troughs 355.

[0092] 3C, the upper portion 304 can be affixed to the lower portion 308 such that the upper portion 304 is further from the ground plane than the lower portion 308. Here, the ground plane 372 contacts the lower portion 308 when the putter head 300 is in an address position to strike a golf ball.

[0093] 3C, the striking face 320 of the putter head 300 includes a striking face center point 376 and a loft plane 380. The striking face center point 376 is equidistant from the crown 342 and the underside of the top portion 304, as well as equidistant from the heel end 316 and the toe end 312 of the putter head 300. The loft plane 380 is tangent to the striking face 320 of the putter head 300. Additionally, the mid-plane 316 intersects the striking face center point 376 and is perpendicular to the loft plane 380. Additionally, with reference to FIG. 3B, a y-axis 388 intersects the mid-plane 384 and is perpendicular to the ground plane 372.

[0094] When the upper portion 304 and lower portion 308 are joined, the heel end 316 overlaps at least a portion of the toe side perimeter 356. Additionally, when the upper portion 304 and lower portion 308 are joined, the toe end 312 overlaps at least a portion of the heel side perimeter 360. Additionally, when the upper portion 304 and lower portion 308 are joined, the striking face 320 overlaps at least a portion of the front edge 316. Finally, the upper portion 304 and lower portion 308 are joined such that the back edge 364 overlaps at least a portion of the rear perimeter 332.

[0095] The front edge 316, rear perimeter 332, toe perimeter 356, and heel perimeter 360 of the lower portion 308 combine with the upper portion 304 to form a sole 368. The sole 368 is perpendicular to a ground plane 372, which is tangent to the sole 368 when the putter head 300 is in an address position to strike a golf ball. The sole 368 of the putter head 300 extends from the toe end 312 of the putter head 300 to the heel end 316 of the putter head 300.

[0096] In most embodiments, the sole 368 of the putter head 300 may be completely flat. In some embodiments, the sole 368 of the putter head 300 may have a slight arch in the direction from the heel 324 to the toe 320, where 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 the heel 324 to the toe 320, where the strong arch may be a linear or polynomial function. The sole 368 functions to provide a surface for the putter head 300 to rest on the ground plane 372.

[0097] 3A , in one embodiment, the lower portion 308 can further comprise a toe mass 341 and a heel mass 343. The toe mass 341 and the heel mass 343 are integral with the lower portion 308 and are in contact with the toe side perimeter 356 and the heel side perimeter 360, respectively. The toe mass 341 and the heel mass 343 extend from the lower portion 308 in a direction away from the ground plane 372 and towards the upper portion 304. The toe mass 341 and the heel mass 343 provide a means for positioning and aligning the upper portion 304 with the lower portion 308 of the putter head 300.

[0098] Additionally, the toe mass 341 and heel mass 343 provide additional means of adding weight to the periphery to increase the MOI of the crescent putter head 300 when compared to a putter without these mass features. These mass features can have weights ranging from 2-5 grams, 3-7 grams, or 1-6 grams. The mass features can all have the same weight or can be of different weights within the above ranges. The weights 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: rectangular, triangular, pyramidal, spherical, crescent, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0099] 3A , the toe mass 341 and the heel mass 343 can be positioned away from the rear perimeter 352, where the toe mass 341 and the heel mass 343 do not contact or intersect the rear perimeter 352. However, in other embodiments, the toe mass 341 and the heel mass 343 can be positioned on the rear perimeter 352, where the toe mass 341 and the heel mass 343 are integral with and intersect the rear perimeter 352.

[0100] In one embodiment, the toe mass 341 is located on the front edge 348 at the junction of the toe side perimeter 356 and the front edge 348, but in other embodiments, the toe mass 341 can be located anywhere along the toe side perimeter 356. In one embodiment, the heel mass 343 is located on the front edge 348 at the junction of the heel side perimeter 360 and the front edge 348, but in other embodiments, the heel mass 343 can be located anywhere along the heel side perimeter 360.

[0101] The toe mass 341 and heel mass 343 provide an area of ​​concentrated mass such that the toe mass 341 and heel mass 343 function to increase the moment of inertia of the putter head 300. Because the toe mass 341 and heel mass 343 are far from the center of gravity of the putter 300, locating the toe mass 341 on or near the front edge 348 and on or near the toe side perimeter 356 and the heel mass 343 on or near the front edge 348 and on or near the heel side perimeter 360, respectively, increases the MOI. The toe mass 341 and heel mass 343 can be integrally formed from a second material, the second material being denser than the first material.

[0102] The toe mass 341 and heel mass 343 serve two functions, as the toe mass 341 and heel mass 343 not only increase the MOI of the putter 300, but also provide an additional surface for the upper portion 304 to bond to the lower portion 308. Thus, the toe mass 341 may also be referred to as the front toe attachment portion 341, and the heel mass 343 may also be referred to as the front heel attachment portion 343.

[0103] In some embodiments, the underside of the upper portion 304, the crown 342, the front edge 370, and the back edge 334 can form a first cavity (not shown). The first cavity extends inwardly from the underside of the toe end 312 toward, but not to, 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 portion 308.

[0104] In some embodiments, the underside of the upper portion 304, the crown 342, the front edge 370, and the back edge 334 can form a second cavity (not shown). The second cavity extends inwardly from the underside of the heel end 316 toward, but not to, 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 receive the heel mass 343 of the lower portion 308.

[0105] The first and second cavities can include any desired geometric shape. However, in most embodiments, the first and second cavities comprise a geometric shape similar or identical to that of the corresponding toe mass 341 or heel mass 343. Furthermore, when the upper portion 304 is secured to the lower portion 308, the first cavity is positioned such that the first cavity surrounds the toe mass 341 and the second cavity is positioned such that the second cavity surrounds the heel mass 343.

[0106] The combination of the lower density first material upper portion 304 and the higher density second material lower portion 308 creates a high MOI putter 300 without creating an excessively heavy putter. The large opening 364 formed by the rear wall 332, rear perimeter 352, toe perimeter 356, and heel perimeter 360 of the lower portion 308 creates a high density, but low volume portion 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-75cc) and mass (340g-385g).

[0107] The lower portion 308, in most embodiments, comprises less than 38% of the volume of the putter 300. In some embodiments, the lower portion 308 comprises less than 37% of the total volume of the putter 300, less than 36% of the total volume of the putter 300, less than 35% of the total volume of the putter 300, less than 34% of the total volume of the putter 300, less than 33% of the total volume of the putter 300, less than 32% of the total volume of the putter 300, less than 31% of the total volume of the putter 300, less than 30% of the total volume of the putter 300, less than 29% of the total volume of the putter 300, less than 28% of the total volume of the putter 300, or less than 27% of the total volume of the putter 300.

[0108] Although the lower portion 308 comprises less than half the volume of the putter 300, the lower portion 308 comprises at least 45% of the total mass of the putter 300. In some embodiments, the lower portion 308 comprises at least 46% of the mass of the putter 300, at least 46% of the mass of the putter 300, at least 47% of the mass of the putter 300, at least 48% of the mass of the putter 300, at least 49% of the mass of the putter 300, at least 50% of the mass of the putter 300, at least 51% of the mass of the putter 300, at least 52% of the mass of the putter 300, at least 53% of the mass of the putter 300, at least 54% of the mass of the putter 300, or at least 55% of the total mass of the putter 300.

[0109] The beneficial shift of mass to the perimeter of the putter head 300 increases the MOI of the putter 300 over a putter having the same volume, mass, and single-material construction (i.e., a putter milled out of a single stainless steel block, or a single-material putter investment cast).

[0110] (c. Semicircular Embodiment) In one embodiment, the putter-type golf club head can be a semicircular putter head 400. With reference to FIGS. 4A-4C, the semicircular putter head 400 has an upper portion 404 and a lower portion 408. The upper portion 404 is made from a first material having a first density and the lower portion 408 is made from a second material having a second density. The first density is less than the second density. The upper portion 404 and the lower portion 408 combine to produce a high MOI putter head 400 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0111] As described above, the lower portion 408 is constructed from a high density material (i.e., the second material). The lower portion 408 includes a front edge 448, a rear perimeter 452, a toe span 456, and a heel span 460. The lower portion 408 and the underside of the upper portion 404 combine to form a sole 468. The front edge 448 is adjacent to the toe span 456 and the heel span 460, and opposite the rear perimeter 452. The toe span 456 is adjacent to the front edge 448 and the rear perimeter 452, and opposite the heel span 460. The heel span 460 is also adjacent to the front edge 448 and the rear perimeter 452, but opposite the toe span 456. The toe span 456 and the heel span 460 extend beyond the rear perimeter 448 of the upper portion 404. In some embodiments, the heel span 460 and the toe span 456 can be parallel, but in some embodiments, the heel span 460 and the toe span 456 are not parallel. In some implementations, the rear perimeter 452 and the front edge 448 can be parallel, but in some implementations, the rear perimeter 452 and the front edge 448 are not parallel. In this embodiment, the rear perimeter 452 is approximately semicircular, and thus the rear perimeter 452 and the front edge 448 are not parallel.

[0112] In most embodiments, the toe span 456 extends perpendicularly from the front edge 448 such that a right angle (90° angle) 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°-180°) can be formed at the junction of the toe span 456 and the front edge 448. Further, in most embodiments, the heel span 460 extends perpendicularly from the front edge 448 such that a right angle (90° angle) 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°-180°) can be formed at the junction of the heel span 460 and the front edge 448.

[0113] The front edge 448, the toe span 456, and the heel span 460 form a gap 464. The gap 464 is bounded by the front edge 448, the toe span 456, and the heel span 460. The gap 464 formed by the front edge 448, the toe span 456, and the heel span 460 moves the majority of the putter's volume and mass to the end of the lower portion 408. While the gap 464 can include any shape, in one embodiment, the gap is approximately rectangular. In other embodiments, the gap 464 can be circular, curvilinear, triangular, trapezoidal, parabolic, golf ball shaped, square, or any other desired geometric shape.

[0114] The top 404 of the putter head 400 includes a toe end 412, a heel end 416, a striking face 420, a rear wall 432, a back edge 434, a crown 442, and an underside (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 generally parallel to the striking face 420. The crown 442 extends away from the striking face 420 to the back edge 434 of the top 404. Additionally, the underside is opposite the crown 442, which spans from the striking face 420 to the back edge 434.

[0115] The crown 442 further descends from the striking face 420 to the back edge 434. Additionally, the crown 442 extends away from the striking face 420, past the front edge 448 of the lower portion 408, to the back edge 434 of the upper portion 404. In most embodiments, the crown 442 spans approximately the inner 25% of the width of the entire club head 400 from the toe span 456 and approximately the inner 25% of the width of the entire club head 400 from the heel span 460. In other embodiments, the crown 442 can span the entire width of the entire club head 400 in a heel-to-toe direction, either continuously or discontinuously. In some embodiments, the crown 442 can span less than 90% of the overall width of the club head 400, less than 90% of the overall width of the club head 400, less than 80% of the overall width of the club head 400, less than 70% of the overall width of the club head 400, less than 60% of the overall width of the club head 400, less than 50% of the overall width of the club head 400, less than 40% of the overall width of the club head 400, or less than 30% of the overall width of the club head 400. Further, in some embodiments, the crown 442 can be substantially flat from the striking face 420 to the back edge 434 or can rise from the striking face 420 to the back edge 434. In most embodiments, the rise or fall of the crown 442 can be a linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0116] 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 the rear wall 432 and is approximately perpendicular to the striking face 420. The alignment trough 455 is bounded by the back edge 434, the rear wall 432, and the crown 442 on the heel end 416, and toe end 412. In most embodiments, the alignment trough 455 provides the viewer with a visual alignment field approximately equal to and extending the width of a golf ball (approximately 4.27 cm).

[0117] Additionally, the top 404 of the putter head 400 may include one or more alignment features 444 on the crown 442. The alignment features 444 may be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment features 444. The alignment features 444 may be evenly spaced across the entire crown 442, a portion of the crown 442, or on the alignment troughs 455. The alignment features 444 extending along the alignment troughs 455 function to provide the viewer with a visual alignment field that extends the width of a 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 to the golf ball using these alignment features 444 along the crown 442 and / or alignment troughs 455.

[0118] 4C, the upper portion 404 is affixed to the lower portion 408 such that the upper portion 404 is further away from the ground plane 472 than the lower portion 408, where the ground plane 472 contacts the lower portion 408 when the putter head 400 is in an address position to strike a golf ball.

[0119] Additionally, the striking face 420 of the putter head 400 comprises a striking face center point 476 and a loft plane 480. The striking face center point 476 is equidistant from the crown 442 and the underside of the top portion 404, as well as equidistant from the heel end 416 and the toe end 412 of the putter head 400. The loft plane 480 is tangent to the striking face 420 of the putter head 400. Additionally, a mid-plane 484 intersects the striking face center point 476 and is perpendicular to the loft plane 480. Additionally, a y-axis 488 intersects the mid-plane 484 and is perpendicular to the ground plane 472.

[0120] When the upper portion 404 and the lower portion 408 are joined, the heel end 416 overlaps at least a portion of the toe span 456. Additionally, when the upper portion 404 and the lower portion 408 are joined, the toe end 412 overlaps at least a portion of the heel span 460. Additionally, when the upper portion 404 and the lower portion 408 are joined, the striking face 420 overlaps at least a portion of the front edge 448. Finally, the upper portion 404 and the lower portion 408 are joined such that the back edge 434 overlaps at least a portion of the rear perimeter 452.

[0121] The rear perimeter 452 may be curvilinear from the heel side 416 to the toe side 416. The rear perimeter 452 includes a curvilinear 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 curvilinear length of the rear perimeter 452 may be between 4.5 inches and 8.0 inches. In some embodiments, the curvilinear length of the rear perimeter 452 may be between 4.5 inches and 4.75 inches, between 4.75 inches and 5.0 inches, between 5.25 inches and 5.5 inches, between 5.75 inches and 6.0 inches, between 6.25 inches and 6.5 inches, between 6.5 inches and 6.75 inches, between 6.75 inches and 7.0 inches, between 7.25 inches and 7.50 inches, or between 7.75 inches and 8.0 inches.

[0122] The front edge 448, rear perimeter 452, toe span 456, and heel span 460 of the lower portion 408 combine with the upper portion 404 to form a sole 468. The sole 468 is perpendicular to a ground plane 472, which contacts the sole 468 when the putter head 400 is in an address position for striking a golf ball. 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.

[0123] In most embodiments, the sole 468 of the putter head 400 may be completely flat. In some embodiments, the sole 468 of the putter head 400 may have a slight arch in the direction from the heel 416 to the toe 412, where 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 the heel 416 to the toe 412, where 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.

[0124] Referring to FIG. 4A, in one embodiment, the lower portion 408 can further comprise a front toe mass 441 and a front heel mass 443. The front toe mass 441 and the front heel mass 443 are integral to the lower portion 408. The front toe mass 441 and the front heel mass 443 extend from the lower portion 408 in a direction away from the ground plane 472 and towards the upper portion 404. These mass features provide a means to position and align the upper portion 404 with the lower portion 408 of the putter head 400. Additionally, these mass features (i.e., the front toe mass 441 and the front heel mass 443) provide an additional means to add weight to the perimeter to increase the MOI of the putter 400 over a putter without these mass features. These mass features can have weights ranging from 2-5 grams, 3-7 grams, or 1-6 grams. The mass features can all have the same weight or can be of different weights within the above ranges. The mass function can 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 can each be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0125] In FIG. 4A, the front toe mass 441 and the front heel mass 443 are located away from the rear perimeter 452. Here, the front toe mass 441 and the front heel mass 443 do not contact or intersect the rear perimeter 452. However, referring to FIGS. 5A-5C, a modified semicircular shaped putter 500 is shown. The putter 500 has the same features as the putter 400, but the front toe mass 541 and the front heel mass 543 of the putter 500 are located on the rear perimeter 552. The front toe mass 541 and the front heel mass 543 are integral with and intersect the rear perimeter 452.

[0126] In one embodiment, the front toe mass 441 is located on the front edge 448 at the junction of the toe side span 456 and the front edge 448. However, in other embodiments, the front toe mass 441 may be located anywhere along the toe side span 456. In one embodiment, the front heel mass 443 is located on the front edge 448 at the junction of the heel side span 460 and the front edge 448. However, in other embodiments, the front heel mass 443 may be located anywhere along the heel side span 460.

[0127] The front toe mass 441 and the front heel mass 443 provide an area of ​​concentrated mass such that each mass 441, 443 functions to increase the moment of inertia of the putter head 400. Locating each mass 441, 443 at the front edge 448 and spans 456, 460 increases the MOI because each mass 441, 443 is away from the center of gravity of the putter 400. Each mass 441, 443 on the perimeter 448 and spans 456, 460 is integrally formed from a second material, the second material being denser than the first material.

[0128] The front toe mass 441 and the front heel mass 443 serve two functions, as the front toe mass 441 and the front heel mass 443 not only increase the MOI of the putter 400, but also provide an additional surface for the upper portion 404 to bond to the lower portion 408. Thus, the front toe mass 441 may also be referred to as the front toe attachment portion 441, and the front heel mass 443 may also be referred to as the front heel attachment portion 443.

[0129] In some embodiments, the underside of the upper portion 404, the striking face 420, and the rear wall 432 can form a first cavity (not shown). The first cavity extends inwardly from the underside of the toe end 412 toward, but not to, 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 a front toe mass 441 of the lower portion 408.

[0130] In some embodiments, the underside of the upper portion 404, the striking face 420, and the rear wall 432 can form a second cavity (not shown). The second cavity extends inwardly from the underside of the heel end 416 toward, but not to, 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 portion 408.

[0131] The first and second cavities can include any desired geometric shape, however, in most embodiments, the first and second cavities include geometric shapes similar or identical to the geometric shapes of the front toe mass 441 and the front heel mass 443. Furthermore, when the upper portion 704 is secured to the lower portion 408, the first cavity is positioned such that the first cavity surrounds the front toe mass 441 and the second cavity is positioned such that the second cavity surrounds the front heel mass 443.

[0132] The combination of a lower density first material upper portion 404 and a higher density second material lower portion 408 creates a high MOI putter 400 without creating an excessively heavy putter. The large gap 464 formed by the spans 456, 460 of the rear perimeter 452 and lower portion 408 creates 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 (340 grams-385 grams).

[0133] The lower portion 408, in most embodiments, comprises less than 38% of the volume of the putter 400. In some embodiments, the lower portion 408 comprises less than 37% of the total volume of the putter 400, less than 36% of the total volume of the putter 400, less than 35% of the total volume of the putter 400, less than 34% of the total volume of the putter 400, less than 33% of the total volume of the putter 400, less than 32% of the total volume of the putter 400, less than 31% of the total volume of the putter 400, less than 30% of the total volume of the putter 400, less than 29% of the total volume of the putter 400, less than 28% of the total volume of the putter 400, or less than 27% of the total volume of the putter 400.

[0134] Although the lower portion 408 comprises less than half the volume of the putter 400, the lower portion 408 comprises at least 45% of the total mass of the putter 400. In some embodiments, the lower portion 408 comprises at least 46% of the mass of the putter 400, at least 46% of the mass of the putter 400, at least 47% of the mass of the putter 400, at least 48% of the mass of the putter 400, at least 49% of the mass of the putter 400, at least 50% of the mass of the putter 400, at least 51% of the mass of the putter 400, at least 52% of the mass of the putter 400, at least 53% of the mass of the putter 400, at least 54% of the mass of the putter 400, or at least 55% of the mass of the putter 400.

[0135] The beneficial shift of mass to the periphery of the putter head 400, through the use of a high density, low volume lower portion 408, increases the MOI of the putter 400 over 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).

[0136] d. Wing-Shaped Embodiments In one embodiment, the putter-type golf club head can be a wing-shaped putter head having a perimeter span 600. With reference to FIGS. 6A and 6B, the wing-shaped putter head 600 has an upper portion 604 and a lower portion 608. The upper portion 604 is made from a first material having a first density and the lower portion 608 is made from a second material having a second density. The first density is less than the second density. The upper portion 604 and the lower portion 608 combine to create a high MOI putter head 600 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0137] As discussed above, the lower portion 608 is constructed from a high density material (i.e., the second material). The lower portion 608 includes a front perimeter 648, a sole 668, a rear perimeter 652, a toe wing 656, and a heel wing 660. As discussed below, FIG. 6C shows the front perimeter 648, rear perimeter 652, toe wing 656, and heel wing 660 of the lower portion 608 combining with the upper portion 604 to create the sole 668. The front perimeter 648 is adjacent to the toe perimeter 656 and heel perimeter 660 and opposite the rear perimeter 652. The toe wing 656 is adjacent to the front perimeter 648 and rear perimeter 652 and opposite the heel wing 660. Additionally, the heel side wing 660 is adjacent to the front perimeter 648 and the rear perimeter 652, but opposite the toe side wing 656. The toe side wing 656 and the heel side wing 660 extend beyond the rear perimeter 648 of the upper 604. In some embodiments, the heel side wing 660 and the toe side wing 656 may be parallel, while in some embodiments, the heel side wing 660 and the toe side wing 656 are not parallel. In some implementations, the rear perimeter 652 and the front perimeter 648 may be parallel, while in some implementations, the rear perimeter 652 and the front perimeter 648 are not parallel.

[0138] In most embodiments, the toe side wing 656 extends perpendicularly from the rear perimeter 652 such that a right angle (90° angle) is formed at the junction of the toe side wing 656 and the rear perimeter 652. However, in other embodiments, the toe side wing 656 can extend in any direction from the rear perimeter 652 such that any angle (0°-180°) can be formed at the junction of the toe side wing 656 and the rear perimeter 652. Further, in most embodiments, the heel side wing 660 extends perpendicularly from the rear perimeter 652 such that a right angle (90° angle) is formed at the junction of the heel side wing 660 and the rear perimeter 652. However, in other embodiments, the heel side wing 660 can extend in any direction from the rear perimeter 652 such that any angle (0°-180°) can be formed at the junction of the heel side wing 660 and the rear perimeter 652.

[0139] The front perimeter 648 of the lower portion 608 comprises a front width. The front width is measured from the junction of the toe wing 656 and the front perimeter 648 to the junction of the heel wing 660 and the front perimeter 648. Additionally, the lower portion 608 has a rear width. The rear width is measured from the tip 657 of the toe wing 656 and the tip 661 of the heel wing 660, where the tip 657 is the point of the toe wing 656 that is furthest from the front perimeter 648 and the tip 661 is the point of the heel wing 660 that is furthest from the front perimeter 648. In most embodiments, the front width is greater than the rear width, however, in some embodiments, the front width can be less than or equal to the rear width.

[0140] 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 moves the majority of the putter's volume and mass to the end of the lower portion 608. While the gap 664 can include any shape, in one embodiment, the gap is approximately rectangular. In other embodiments, the gap 664 may be circular, curvilinear, triangular, trapezoidal, parabolic, golf ball shaped, square, or any other desired geometric shape.

[0141] The top 604 of the putter head 600 includes a toe end 612, a heel end 616, a striking face 620, a rear wall 632, a back edge 634, a crown 642, and an underside (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 generally parallel to the striking face 620. The crown 642 extends away from the striking face 620 to the back edge 634 of the top 604. Additionally, the underside is opposite the crown 642, which spans from the striking face 620 to the back edge 634.

[0142] The crown 642 further descends from the striking face 620 to the back edge 634. Additionally, the crown 642 extends away from the striking face 620, past 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 spans approximately the inner 25% of the total club head 600 width from the toe wing 656 and approximately the inner 25% of the total club head 600 width from the heel wing 660. In other embodiments, the crown 642 can span the entire width of the entire club head 600 in a heel-to-toe direction, either continuously or discontinuously. In some embodiments, the crown 642 can span less than 90% of the overall width of the club head 600, less than 90% of the overall width of the club head 600, less than 80% of the overall width of the club head 600, less than 70% of the overall width of the club head 600, less than 60% of the overall width of the club head 600, less than 50% of the overall width of the club head 600, less than 40% of the overall width of the club head 600, or less than 30% of the overall width of the club head 600. Further, in some embodiments, the crown 642 can be substantially flat from the striking face 620 to the back edge 634 or can rise from the striking face 620 to the back edge 634. In most embodiments, the rise or fall of the crown 642 can be a linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0143] 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 the rear wall 632 and is approximately perpendicular to the striking 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 toe end 612. In most embodiments, the alignment trough provides the viewer with a visual alignment field approximately equal to the width of a golf ball (approximately 4.27 cm) and extending the width of the golf ball.

[0144] Additionally, the top 604 of the putter head 600 may include one or more alignment features 644 on the crown 642. The alignment features 644 may be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment features 644. The alignment features 644 may be evenly spaced across the entire crown 642, a portion of the crown 642, or on the alignment troughs 655. The alignment features 644 extending along the alignment troughs 655 function to provide the 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 objective is to align the entire putter 600 to the golf ball using these alignment features 644 along the crown 642 and / or alignment troughs 655.

[0145] The upper portion 604 is affixed to the lower portion 608 such that the upper portion 604 is farther 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 an address position to strike a golf ball.

[0146] Additionally, the striking face 620 of the putter head 600 comprises a striking face center point 676 and a loft plane 680. The striking face center point 676 is equidistant from the crown 642 and the underside of the top portion 604, as well as equidistant from the heel end 616 and the toe end 612 of the putter head 600. The loft plane 680 is tangent to the striking face 620 of the putter head 600. Additionally, a mid-plane 684 intersects the striking face center point 676 and is perpendicular to the loft plane 680. Additionally, a y-axis 688 intersects the mid-plane 684 and is perpendicular to the ground plane 672.

[0147] When the upper portion 604 and lower portion 608 are joined, the heel end 616 overlaps at least a portion of the toe wing 656. Additionally, when the upper portion 604 and lower portion 608 are joined, the toe end 612 overlaps at least a portion of the heel wing 660. Additionally, when the upper portion 604 and lower portion 608 are joined, the striking face 620 overlaps at least a portion of the front perimeter 648. Finally, the upper portion 604 and lower portion 608 are joined such that the back edge 634 overlaps at least a portion of the rear perimeter 652.

[0148] 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 create a sole 668. The sole 668 is perpendicular to a ground plane 672. The ground plane 672 is tangent to the sole 668 when the putter head 600 is in an address position to strike a golf ball. The sole 668 of the putter head 600 extends from a toe end 612 of the putter head 600 to a heel end 616 of the putter head 600.

[0149] In most embodiments, the sole 668 of the putter head 600 may be completely flat. In some embodiments, the sole 668 of the putter head 600 may have a slight arch in the direction from the heel 616 to the toe 612, where 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 the heel 616 to the toe 612, where the strong arch may be a linear or polynomial function. The sole 668 functions to provide a surface for the putter head 600 to rest on the ground plane 672.

[0150] 6A , in one embodiment, the lower portion 608 can 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, the front heel mass 643, the toe wing mass 645, and the heel wing mass 647 are integral to the lower portion 608. The front toe mass 641, the front heel mass 643, the toe wing mass 645, and the heel wing mass 647 extend from the lower portion 608 in a direction away from the ground plane 672 and towards the upper portion 604. These masses provide a means for positioning and aligning the upper portion 604 with the lower portion 608 of the putter head 600. Additionally, these mass features (i.e., front toe mass 641, front heel mass 643, toe wing mass 645, and heel wing mass 647) provide additional means of adding weight to the perimeter to increase the MOI of the putter 600 over a putter without these mass features. These mass features can have weights ranging from 2-5 grams, 3-7 grams, or 1-6 grams. The mass features can all have the same weight or can be different weights within the above ranges. The mass features 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.

[0151] In one embodiment, the front toe mass 641 is located on the front perimeter 648 at the junction of the toe wing 656 and the front perimeter 648. However, in other embodiments, the front toe mass 641 may be located anywhere along the front perimeter 648. In one embodiment, the front heel mass 643 is located on the front perimeter 648 at the junction of the heel wing 660 and the front perimeter 648. However, in other embodiments, the front heel mass 643 may be located anywhere along the front perimeter 648. In one embodiment, the toe wing mass 645 may be located on a portion of the toe wing 656, while in other embodiments, the toe wing mass 645 may be located anywhere along a portion or the entirety of the toe wing 656. In one embodiment, the heel wing mass 647 may be located on a portion of the heel wing 660, while in other embodiments, the heel wing mass 647 may be located along a portion or the entirety of the heel wing 660.

[0152] The front toe mass 641, the front heel wing mass 643, the toe wing mass 645, and the heel wing mass 647 provide areas of concentrated mass such that each mass 641, 643, 645, and 647 functions to increase the moment of inertia of the putter head 600. Locating each mass 641, 643, 645, and 647 on the perimeter 648 and wings 656, 660 increases the MOI by moving each mass 641, 643, 645, and 647 away from the center of gravity of the putter 600. Each mass 641, 643, 645, 647 on the perimeter 648 and wings 656, 660 is integrally formed from a second material, the second material being denser than the first material.

[0153] The front toe mass 641 and the front heel mass 643 serve two functions, as the front toe mass 641 and the front heel mass 643 not only increase the MOI of the putter 600, but also provide an additional surface for the upper portion 604 to bond to the lower portion 608. Thus, the front toe mass 641 may also be referred to as the front toe attachment portion 641, and the front heel mass 643 may also be referred to as the front heel attachment portion 643.

[0154] In some embodiments, the underside of the upper portion 604, the striking face 620, and the rear wall 632 can form a first cavity (not shown). The first cavity extends inwardly from the underside above the toe end 612 toward, but not to, 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 portion 608.

[0155] In some embodiments, the underside of the upper portion 604, the striking face 620, and the rear wall 632 can form a second cavity (not shown). The second cavity extends inwardly from the underside above the heel end 616 toward, but not to, 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 portion 608.

[0156] The first and second cavities can include any desired geometric shape, however, in most embodiments, the first and second cavities include geometric shapes similar or identical to the geometric shapes of the front toe mass 641 and the front heel mass 643. Furthermore, when the upper portion 604 is secured to the lower portion 608, the first cavity is positioned such that the first cavity surrounds the front toe mass 641 and the second cavity is positioned such that the second cavity surrounds the front heel mass 643.

[0157] The combination of a lower density first material upper portion 604 and a higher density second material lower portion 608 creates a high MOI putter 600 without creating an excessively heavy putter. The large gap 664 formed by the rear perimeter 652 and wings 656, 660 of the lower portion 608 creates 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).

[0158] The lower portion 608, in most embodiments, comprises less than 38% of the total volume of the putter 600. In some embodiments, the lower portion 608 comprises less than 37% of the total volume of the putter 600, less than 36% of the total volume of the putter 600, less than 35% of the total volume of the putter 600, less than 34% of the total volume of the putter 600, less than 33% of the total volume of the putter 600, less than 32% of the total volume of the putter 600, less than 31% of the total volume of the putter 600, less than 30% of the total volume of the putter 600, less than 29% of the total volume of the putter 600, less than 28% of the total volume of the putter 600, or less than 27% of the total volume of the putter 600.

[0159] Although the lower portion 608 comprises less than half the volume of the putter 600, the lower portion 608 comprises at least 45% of the overall mass of the putter 600. In some embodiments, the lower portion 608 comprises at least 46% of the overall mass of the putter 600, at least 46% of the overall mass of the putter 600, at least 47% of the overall mass of the putter 600, at least 48% of the overall mass of the putter 600, at least 49% of the overall mass of the putter 600, at least 50% of the overall mass of the putter 600, at least 51% of the overall mass of the putter 600, at least 52% of the overall mass of the putter 600, at least 53% of the overall mass of the putter 600, at least 54% of the overall mass of the putter 600, or at least 55% of the overall mass of the putter 600.

[0160] The beneficial shift of mass to the periphery of the putter head 600 by using a high density, low volume lower portion 608 increases the MOI of the putter 600 over a putter having the same volume, mass, and single material construction (i.e., a putter milled out of a single stainless steel block, or a single material putter investment cast).

[0161] e. Spade Embodiment In one embodiment, the putter-type golf club head can be a spade-shaped putter head having a perimeter span 700. With reference 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 from a first material having a first density and the lower portion 708 is made from 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 combine to create a high MOI putter head 700 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0162] As discussed above, the lower portion 708 is constructed from a high density material (i.e., the first material), thereby lowering mass below the midline 784. The lower portion 708 includes a front perimeter 748, a rear perimeter 752, a toe side perimeter 756, and a heel side perimeter 760. The front perimeter 748 is adjacent to the toe side perimeter 756 and the heel side perimeter 760 and is opposite the rear perimeter 752. The toe side perimeter 756 is adjacent to the front perimeter 748 and the rear perimeter 752 and is opposite and opposite the heel side perimeter 760. The heel side perimeter 760 is also adjacent to the front perimeter 748 and the rear perimeter 752, but is opposite the toe side perimeter 756. In some embodiments, the heel side perimeter 760 and the toe side perimeter 756 can be parallel, but in some embodiments, the heel side perimeter 760 and the toe side perimeter 756 are not parallel. In some embodiments, the rear perimeter 752 and the front perimeter 748 can be parallel, while in some embodiments, the rear perimeter 752 and the front perimeter 748 are not parallel.

[0163] The front perimeter 748 of the lower portion 708 comprises a front width. The front width is measured from the junction of the toe side perimeter 756 and the front perimeter 748 to the junction of the heel side perimeter 760 and the front perimeter 748. And, the rear perimeter 752 of the lower portion 708 comprises a rear width. The rear width is measured from the junction of the toe side perimeter 756 and the rear perimeter 752 to the junction of 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.

[0164] The front perimeter 748, rear perimeter 752, toe side perimeter 756, and heel side perimeter 760 join to form an opening 764, where 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, 760 form a perimeter around the opening 764. The central opening 764 formed by the perimeters 756, 752, 756, 760 of the lower portion 708 moves the majority of the putter's volume and mass to the end of the lower portion 708.

[0165] The top 704 of the putter head 700 includes 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 lower 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 generally parallel to the striking face 720. The crown 742 extends away from the striking face 720, over at least a portion of the rear wall 732, to the back edge 734 of the top 704. Additionally, the lower surface is opposite the crown 742 and extends from the striking face 720 to the back edge 734.

[0166] The crown 742 further descends from the striking face 720 to the back edge 734. Additionally, the crown 742 extends away from the striking face 720, over at least a portion of the rear wall 732 and the opening 764 in the lower portion 708, to the back edge 734 of the upper portion 704. The crown 742 in most embodiments spans the inner 25% of the width of the entire club head 700 from the toe side perimeter 756 and the heel side perimeter 760. In this embodiment, the crown 742 spans approximately 50% of the width of the club head 700. In other embodiments, the crown 742 can span the entire width of the entire club head 700 in a heel-to-toe direction. In some embodiments, the crown 742 can span less than 90% of the overall width of the club head 700, less than 90% of the overall width of the club head 700, less than 80% of the overall width of the club head 700, less than 70% of the overall width of the club head 700, less than 60% of the overall width of the club head 700, less than 50% of the overall width of the club head 700, less than 40% of the overall width of the club head 700, or less than 30% of the overall width of the club head 700. Further, in some embodiments, the crown 742 can be substantially flat from the striking face 720 to the back edge 734 or can rise from the striking face 720 to the back edge 734. In most embodiments, the rise or fall of the crown 742 can be a linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0167] Additionally, the top 704 of the putter head 700 may include one or more alignment features 744 on the crown 742. The alignment features 744 may be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment features 744. The alignment features 744 are evenly spaced across the crown 742, which is configured to be the width of a golf ball (approximately 4.27 cm). The alignment features 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 use these alignment features 744 along the crown 742 to align the entire putter 700 to the golf ball.

[0168] 7C, the upper portion 704 is affixed to the lower portion 708 such that the upper portion 704 is further away from the ground plane 772 than the lower portion 708, where the ground plane 772 contacts the lower portion 708 when the putter head 700 is in an address position to strike a golf ball.

[0169] Additionally, the striking face 720 of the putter head 700 comprises a striking face center point 776 and a loft plane 780. The striking face center point 776 is equidistant from the crown 742 and the underside of the top portion 704 as well as equidistant from the heel end 716 and toe end 712 of the putter head 700. The loft plane 780 is tangent to the striking face 720 of the putter head 700. Additionally, a mid-plane 784 intersects the striking face center point 776 and is perpendicular to the loft plane 780. Additionally, a y-axis 788 intersects the mid-plane 784 and is perpendicular to the ground plane 772.

[0170] When the upper portion 704 and lower portion 708 are joined, the heel end 716 overlaps at least a portion of the toe side perimeter 756. Additionally, when the upper portion 704 and lower portion 708 are joined, the toe end 712 overlaps at least a portion of the heel side perimeter 760. Additionally, when the upper portion 704 and lower portion 708 are joined, the striking face 720 overlaps at least a portion of the front perimeter 748. Finally, the upper portion 704 and lower portion 708 are joined such that the back edge 734 overlaps at least a portion of the rear perimeter 752.

[0171] The four perimeter portions of the lower portion 708 (front 748, rear 752, toe side 756, and heel side 760) combine with the upper portion 704 to create a sole 768. The sole 768 is perpendicular to a ground plane 772. The ground plane 772 contacts the sole 768 when the putter head 700 is in an address position to strike a golf ball. The sole 768 of the putter head 700 extends from a toe end 712 of the putter head 700 to a heel end 716 of the putter head 700.

[0172] In most embodiments, the sole 768 of the putter head 700 may be completely flat. In some embodiments, the sole 768 of the putter head 700 may have a slight arch in the direction from the heel 716 to the toe 712, where 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 the heel 716 to the toe 712, where 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.

[0173] 7A, in one embodiment, the lower portion 708 can further comprise a front mass 741, a rear mass 743, a toe mass 745, and a heel mass 747. The front mass 741, the rear mass 743, the toe mass 745, and the heel mass 747 are integral to the lower portion 708. The front mass 741, the rear mass 743, the toe mass 745, and the heel mass 747 extend from the lower portion 708 in a direction away from the ground plane 772 and towards the upper portion 704. These masses provide a means for positioning and aligning the upper portion 704 with the lower portion 708 of the putter head 700. Additionally, these masses (i.e., the front mass 741, the rear mass 743, the toe mass 745, and the heel mass 747) provide an additional means for adding weight to the perimeter to increase the MOI of the putter 700 over putters that do not have these mass features. These mass features can have weights ranging from 2-5 grams, 3-7 grams, or 1-6 grams. The mass features can all have the same weight or can be different weights within the above ranges. The mass features can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The front mass 741, rear mass 743, toe mass 745, and heel mass 747 can each be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0174] In one embodiment, the front mass 741 is located on the front perimeter 748 and is equidistant from the toe side perimeter 756 and the heel side perimeter 760. However, in other embodiments, the front mass 741 may be located anywhere along the front perimeter 748. In one embodiment, the rear mass 743 is located on the rear perimeter 752 and is equidistant from the toe side perimeter 756 and the heel side perimeter 760. However, in other embodiments, the rear mass 743 may be located anywhere along the rear perimeter 752. In one embodiment, the toe mass 745 may be located at the junction of the toe side perimeter 756 and the rear perimeter 752. However, in other embodiments, the toe mass 745 may be located anywhere along the toe side perimeter 756. In one embodiment, the heel mass 747 may be located at the junction of the heel side perimeter 760 and the rear perimeter 752. However, in other embodiments, the heel mass 747 may be located anywhere along the heel side perimeter 760.

[0175] The front mass 741, rear mass 743, toe mass 745, and heel mass 747 provide areas of concentrated mass such that each mass 741, 743, 745, and 747 functions to increase the moment of inertia of the putter head 700. By locating each mass 741, 743, 745, and 747 on each mass 748, 752, 756, 760, the MOI is increased since each mass 741, 743, 745, and 747 is away from the center of gravity of the putter 700. Each mass 741, 743, 745, 747 on the periphery 748, 752, 756, 760 is integrally formed from a second material, the second material being denser than the first material.

[0176] The front mass 741 and rear mass 743 serve two functions, as the front mass 741 and rear mass 743 not only increase the MOI of the putter 700, but also function to provide an additional surface for the upper portion 704 to interface with the lower portion 708. Thus, the front mass 741 can also be referred to as the front attachment 741 and the rear mass 743.

[0177] In some embodiments, the lower surface of the upper portion 704, the striking face 720, and the rear wall 732 can form a first cavity (not shown). The first cavity extends inwardly from the lower surface toward, 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 portion 708.

[0178] In some embodiments, the lower surface, the back edge 734, and the crown 742 form a second cavity (not shown). The second cavity extends inward from the lower 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 portion 708 is joined to the upper portion 704. The second cavity functions to receive the rear mass 743 of the lower portion 708.

[0179] The first and second cavities can include any desired geometric shape, but in most embodiments the first and second cavities include geometric shapes similar or identical to the geometric shapes of the front mass 741 and the rear mass 743. Furthermore, when the upper portion 704 is secured to the lower portion 708, the first cavity is positioned such that the first cavity surrounds the front mass 741 and the second cavity is positioned such that the second cavity surrounds the rear mass 743.

[0180] The combination of the low density first material upper portion 704 and the high density second material lower portion 708 creates a high MOI putter 700 without creating an excessively heavy putter. The large opening 764 formed by the perimeter portions 748, 752, 756, 760 of the lower portion 708 creates 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 (340 grams-385 grams).

[0181] The lower portion 708, in most embodiments, comprises less than 35% of the total volume of the putter 700. In some embodiments, the lower portion 708 comprises less than 34% of the total volume of the putter 700, less than 33% of the total volume of the putter 700, less than 32% of the total volume of the putter 700, less than 31% of the total volume of the putter 700, less than 30% of the total volume of the putter 700, less than 29% of the total volume of the putter 700, less than 28% of the total volume of the putter 700, or less than 27% of the total volume of the putter 700.

[0182] Although the lower portion 708 comprises less than half the volume of the putter 700, the lower portion 708 comprises at least 45% of the total mass of the putter 700. In some embodiments, the lower portion 708 comprises 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 700, at least 49% of the mass of the putter 700, at least 50% of the mass of the putter 700, at least 51% of the mass of the putter 700, at least 52% of the mass of the putter 700, at least 53% of the mass of the putter 700, at least 54% of the mass of the putter 700, or at least 55% of the mass of the putter 700.

[0183] The beneficial shift of mass to the periphery of the putter head 700, through the use of a high density, low volume lower portion 708, increases the MOI of the putter 700 versus 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).

[0184] f. T-Shaped Embodiment with Perimeter Span In one embodiment, the putter-type golf club head can be a T-shaped putter head with a perimeter span 800. With reference to FIGS. 8A and 8B, the T-shaped putter head with perimeter span 800 has an upper portion 804 and a lower portion 808. The upper portion 804 is made from a first material having a first density and the lower portion 808 is made from a second material having a second density. The first density is less than the second density. The upper portion 804 and the lower portion 808 combine to create a high MOI putter head 800 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0185] As discussed above, the lower portion 808 is constructed from a high density material (i.e., the second material), thereby lowering mass below the midline 884. The lower portion 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 is opposite the rear perimeter 852. The toe side perimeter 856 is adjacent to the front perimeter 848 and the rear perimeter 852 and is opposite the heel side perimeter 860. The heel side perimeter 860 is also adjacent to the front perimeter 848 and the rear perimeter 852, but is opposite the toe side perimeter 856. In some embodiments, the heel side perimeter 860 and the toe side perimeter 856 can 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 perimeter 852 and the front perimeter 848 can be parallel, while in some embodiments, the rear perimeter 852 and the front perimeter 848 are not parallel.

[0186] The front perimeter 848 of the lower portion 808 comprises a front width. The front width is measured from the junction of the toe side perimeter 856 and the front perimeter 848 to the junction of the heel side perimeter 860 and the front perimeter 848. And, the rear perimeter 852 of the lower portion 808 comprises a rear width. The rear width is measured from the junction of the toe side perimeter 856 and the rear perimeter 852 to the junction of the heel side perimeter 860 and the rear perimeter 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.

[0187] The front perimeter 848, rear perimeter 852, toe side perimeter 856, and heel side perimeter 860 join to form an opening 864, where 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, 860 form a perimeter around the opening 864. The central opening 864 formed by the perimeters 856, 852, 856, 860 of the lower portion 808 moves the majority of the putter's volume and mass to the end of the lower portion 808.

[0188] In some embodiments, the opening 864 formed by the front perimeter 848, the rear perimeter 852, the toe side perimeter 856, and the heel side perimeter 860 can be any one of the following shapes: rectangular, triangular, semicircular, circular (golf ball size), circular (larger than a golf ball), circular (smaller than a golf ball), square, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0189] The top 804 of the putter head 800 includes 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 lower 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 generally parallel to the striking face 820. The crown 842 extends away from the striking face 820, over at least a portion of the rear wall 832, to the back edge 834 of the top 804. Additionally, the lower surface is opposite the crown 842 and extends from the striking face 820 to the back edge 834.

[0190] The crown 842 further descends from the striking face 820 to the back edge 834. Additionally, the crown 842 extends away from the striking face 820, over at least a portion of the rear wall 832 and the opening 864 in the lower portion 808, to the back edge 834 of the upper portion 804. The crown 842 in most embodiments spans the inner 25% of the width of the entire club head 800 from the toe perimeter 856 and the heel perimeter 860. In this embodiment, the crown 842 spans approximately 50% of the width of the club head 800, thus forming a "T-shape" with the striking face. In other embodiments, the crown 842 can span the entire width of the entire club head 800 in a heel-to-toe direction. In some embodiments, the crown 842 can span less than 90% of the overall width of the club head 800, less than 90% of the overall width of the club head 800, less than 80% of the overall width of the club head 800, less than 70% of the overall width of the club head 800, less than 60% of the overall width of the club head 800, less than 50% of the overall width of the club head 800, less than 40% of the overall width of the club head 800, or less than 30% of the overall width of the club head 800. Further, in some embodiments, the crown 842 can be substantially flat from the striking face 820 to the back edge 834 or 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 linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0191] Additionally, the top 804 of the putter head 800 may include one or more alignment features 844 on the crown 842. The alignment features 844 may be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment features 844. The alignment features 844 are evenly spaced across the crown 842, which is configured to be the width of a golf ball (approximately 4.27 cm). The alignment features 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 purpose is to use these alignment features 844 along the crown 842 to align the entire putter 800 with a golf ball.

[0192] 8C, the upper portion 804 is affixed to the lower portion 808 such that the upper portion 804 is farther from the ground plane 872 than the lower portion 808, where the ground plane 872 contacts the lower portion 808 when the putter head 800 is in an address position to strike the golf ball.

[0193] Additionally, the striking face 820 of the putter head 800 comprises a striking face center point 876 and a loft plane 880. The striking face center point 876 is equidistant from the crown 842 and the underside of the top portion 804, as well as equidistant from the heel end 816 and the toe end 812 of the putter head 800. The loft plane 880 is tangent to the striking face 820 of the putter head 800. Additionally, a mid-plane 884 intersects the striking face center point 876 and is perpendicular to the loft plane 880. Additionally, a y-axis 888 intersects the mid-plane 884 and is perpendicular to the ground plane 872.

[0194] When the upper portion 804 and the lower portion 808 are joined, the heel end 816 overlaps at least a portion of the toe side perimeter 856. Additionally, when the upper portion 804 and the lower portion 808 are joined, the toe end 812 overlaps at least a portion of the heel side perimeter 860. Additionally, when the upper portion 804 and the lower portion 808 are joined, the striking face 820 overlaps at least a portion of the front perimeter 848. Finally, the upper portion 804 and the lower portion 808 are joined such that the back edge 834 overlaps at least a portion of the rear perimeter 852.

[0195] The four perimeter portions of the lower portion 808 (front 848, rear 852, toe side 856, and heel side 860) combine with the upper portion 804 to form a sole 868. The sole 868 is perpendicular to a ground plane 872. The ground plane 872 contacts the sole 868 when the putter head 800 is in an address position to strike a golf ball. The sole 868 of the putter head 800 extends from a toe end 812 of the putter head 800 to a heel end 816 of the putter head 800.

[0196] In most embodiments, the sole 868 of the putter head 800 may be completely flat. In some embodiments, the sole 868 of the putter head 800 may have a slight arch in the direction from the heel 816 to the toe 812, where 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 the heel 816 to the toe 812, where 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.

[0197] 8A, in one embodiment, the lower portion 808 can further comprise a front mass 841, a rear mass 843, a toe mass 845, and a heel mass 847. The front mass 841, the rear mass 843, the toe mass 845, and the heel mass 847 are integral with the lower portion 808. The front mass 841, the rear mass 843, the toe mass 845, and the heel mass 847 extend from the lower portion 808 in a direction away from the ground plane 872 and toward the upper portion 804. These masses provide a means for positioning and aligning the upper portion 804 with the lower portion 808 of the putter head 800. Additionally, these masses (i.e., the front mass 841, the rear mass 843, the toe mass 845, and the heel mass 847) provide an additional means for adding weight to the perimeter to increase the MOI of the putter 800 over putters that do not have these mass features. These mass features can have weights ranging from 2-5 grams, 3-7 grams, or 1-6 grams. The mass features can all have the same weight or can be different weights within the above ranges. The mass features can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The front mass 841, rear mass 843, toe mass 845, and heel mass 847 can each be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0198] In one embodiment, the front mass 841 is located on the front perimeter 848 and is equidistant from the toe side perimeter 856 and the heel side perimeter 860. However, in other embodiments, the front mass 841 may be located anywhere along the front perimeter 848. In one embodiment, the rear mass 843 is located on the rear perimeter 852 and is equidistant from the toe side perimeter 856 and the heel side perimeter 860. However, in other embodiments, the rear mass 843 may be located anywhere along the rear perimeter 852. In one embodiment, the toe mass 845 may be located at the junction of the toe side perimeter 856 and the rear perimeter 852. However, in other embodiments, the toe mass 845 may be located anywhere along the toe side perimeter 856. In one embodiment, the heel mass 847 may be located at the junction of the heel side perimeter 860 and the rear perimeter 852. However, in other embodiments, the heel mass 847 may be located anywhere along the heel side perimeter 860.

[0199] The front mass 841, rear mass 843, toe mass 845, and heel mass 847 provide areas of concentrated mass such that each mass 841, 843, 845, and 847 functions to increase the moment of inertia of the putter head 800. The placement of each mass 841, 843, 845, and 847 on the perimeter 848, 852, 856, 860 increases the MOI since each mass 841, 843, 845, and 847 is further from the center of gravity of the putter 800. Each mass 841, 843, 845, 847 on the perimeter 848, 852, 856, 860 is integrally formed from a second material, the second material being denser than the first material.

[0200] The front mass 841 and rear mass 843 serve two functions, as the front mass 841 and rear mass 843 not only increase the MOI of the putter 800, but also function to provide an additional surface for the upper portion 804 to bond to the lower portion 808. Thus, the front mass 841 can also be referred to as the front attachment 841 and the rear mass 843.

[0201] In some embodiments, the lower surface of the upper portion 804, the striking face 820, and the rear wall 832 can form a first cavity (not shown). The first cavity extends inwardly from the lower surface toward, 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 portion 808.

[0202] In some embodiments, the lower surface, the back edge 834, and the crown 842 form a second cavity (not shown). The second cavity extends inward from the lower 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 portion 808 is joined to the upper portion 804. The second cavity functions to receive the rear mass 843 of the lower portion 808.

[0203] The first and second cavities can include any desired geometric shape, but in most embodiments the first and second cavities include geometric shapes similar or identical to the geometric shapes of the front mass 841 and the rear mass 843. Furthermore, when the upper portion 804 is secured to the lower portion 808, the first cavity is positioned such that the first cavity surrounds the front mass 841 and the second cavity is positioned such that the second cavity surrounds the rear mass 843.

[0204] The combination of a lower density first material upper portion 804 and a higher density second material lower portion 808 creates a high MOI putter 800 without creating an excessively heavy putter. The large opening 864 formed by the perimeter portions 848, 852, 856, 860 of the lower portion 808 creates 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 (340 grams-385 grams).

[0205] The lower portion 808, in most embodiments, comprises less than 35% of the total volume of the putter 800. In some embodiments, the lower portion 908 comprises less than 34% of the total volume of the putter 800, less than 33% of the total volume of the putter 800, less than 32% of the total volume of the putter 800, less than 31% of the total volume of the putter 800, less than 30% of the total volume of the putter 800, less than 29% of the total volume of the putter 800, less than 28% of the total volume of the putter 800, or less than 27% of the total volume of the putter 800.

[0206] Although the lower portion 808 comprises less than half the volume of the putter 800, the lower portion 808 comprises at least 45% of the overall mass of the putter 800. In some embodiments, the lower portion 808 comprises at least 46% of the mass of the putter 800, at least 46% of the mass of the putter 800, at least 46% of the mass of the putter 800, at least 47% of the mass of the putter 800, at least 48% of the mass of the putter 800, at least 49% of the mass of the putter 800, at least 50% of the mass of the putter 800, at least 51% of the mass of the putter 800, at least 52% of the mass of the putter 800, at least 53% of the mass of the putter 800, at least 54% of the mass of the putter 800, or at least 55% of the mass of the putter 800.

[0207] The beneficial shift of mass to the periphery of the putter head 800, through the use of a high density, low volume lower portion 808, increases the MOI of the putter 800 versus 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).

[0208] g. Dual Rail Embodiment In another embodiment, the putter-type golf club head can be a dual rail putter head 900. With reference to FIGS. 9A and 9B, the dual rail putter head 900 has an upper portion 904 and a lower portion 908. The upper portion 904 is made from a first material having a first density and the lower portion 908 is made from a second material having a second density. The first density is less than the second density. The upper portion 904 and the lower portion 908 combine to create a high MOI putter head 900 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0209] As mentioned above, the lower portion 908 is constructed from a high density material (i.e., the second material), thereby lowering the mass below the midline 984. The lower portion 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 is opposite the rear perimeter 952. The toe side perimeter 956 is adjacent to the front perimeter 948 and the rear perimeter 952 and is opposite the heel side perimeter 960. The heel side perimeter 956 is also adjacent to the front perimeter 948 and the rear perimeter 952, but is opposite 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 perimeter 952 and the front perimeter 948 can be parallel, while in some embodiments, the rear perimeter 952 and the front perimeter 948 are not parallel.

[0210] The front perimeter 948 of the lower portion 908 has a front width. The front width is measured from the junction of the toe side perimeter 956 and the front perimeter 948 to the junction of the heel side perimeter 960 and the front perimeter 948. Additionally, the rear perimeter 952 of the lower portion 908 has a rear width. The rear width is measured from the junction of the toe side perimeter 956 and the rear perimeter 952 to the junction of the heel side perimeter 960 and the rear perimeter 952. In most embodiments, the front width is greater than the rear width, however, in some embodiments, the front width can be less than or equal to the rear width.

[0211] The front perimeter 948, rear perimeter 952, toe side perimeter 956, and heel side perimeter 960 join to form an opening 964, where 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, 960 form a perimeter around the opening 964. The central opening 964 formed by the perimeters 948, 952, 956, 960 of the lower portion 908 moves the majority of the putter's volume and mass to the ends of the lower portion 908.

[0212] In some embodiments, the opening 964 formed by the front perimeter 948, the rear perimeter 952, the toe side perimeter 956, and the heel side perimeter 960 can be any one of the following shapes: rectangular, triangular, semicircular, circular (golf ball size), circular (larger than a golf ball), circular (smaller than a golf ball), square, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0213] The top 904 of the dual rail putter head 900 includes 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 lower 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 generally parallel to the striking face 920. The crown 942 extends away from the striking face 920, over at least a portion of the rear wall 932, to the back edge 934 of the top 904. Additionally, the lower surface is opposite the crown 942 and extends from the striking face 920 to the back edge 934.

[0214] The crown 942 of the upper portion 904 further comprises a toe-end mid-rail 936 and a heel-end mid-rail 940. In most embodiments, the toe-end mid-rail 936 and the heel-end mid-rail 940 are generally parallel while perpendicular to the striking face 920. Additionally, the toe-end mid-rail 936 and the heel-end mid-rail 940 do not contact the toe-side perimeter 956 or the heel-side perimeter 960. The toe-end mid-rail 936 and the heel-end mid-rail 940 are approximately 1 / 3 of the total club head width inboard from the perimeters of the toe-side perimeter 956 and the heel-side perimeter 960, respectively. However, in other embodiments, the toe-end mid-rail 936 and the heel-end mid-rail 940 can be more than 1 / 3 of the total club head width inboard from the perimeters of the toe-side perimeter and the heel-side perimeter, respectively. The toe-end mid-rail 936 and the heel-end mid-rail 940 descend from the striking face 920 to the back edge 934. In some embodiments, the toe-end mid-rail 936 and heel-end mid-rail 940 are not parallel and are not perpendicular to the striking face 920. In some embodiments, the toe-end mid-rail 936 and heel-end mid-rail 940 may be substantially flat from the striking face 920 to the back edge 934, or may rise from the striking face 920 to the back edge 934. In most embodiments, the rise or fall of the mid-rails 936, 940 may be a linear, curvilinear, parabolic, sinusoidal, or polynomial function.

[0215] Additionally, the top 904 of the dual rail putter head 900 may include one or more alignment features 944 on the toe end mid-rail 936 and heel end mid-rail 940. The alignment features 944 may be any one or combination of lines, circles, dashed lines, triangles, channels, or any other desired alignment features 944. The alignment features 944 are spaced apart on the rails 936, 940 to be the width of a golf ball (approximately 4.27 cm). The alignment features 944 extend along the rails to 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 use these alignment features 944 along the toe end mid-rail 936 and heel end mid-rail 940 to align the entire putter 900 to the golf ball.

[0216] The upper portion 904 is affixed to the lower portion 908 such that the upper portion 904 is farther away from the ground plane 972 than the lower portion 908. The ground plane 972 contacts the lower portion 908 when the dual rail putter head 900 is in an address position to strike a golf ball.

[0217] Additionally, the striking face 920 of the dual rail putter head 900 comprises a striking face center point 976 and a loft plane 980. The striking face center point 976 is equidistant from the crown 942 and the underside of the top portion 904, as well as equidistant from the heel end 916 and the 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. Additionally, a mid-plane 984 intersects the striking face center point 976 and is perpendicular to the loft plane 980. Additionally, a y-axis 988 intersects the mid-plane 984 and is perpendicular to the ground plane 972.

[0218] When the upper portion 904 and lower portion 908 are joined, the heel end 916 overlaps at least a portion of the toe side perimeter 956. Additionally, when the upper portion 904 and lower portion 908 are joined, the toe end 912 overlaps at least a portion of the heel side perimeter 960. Additionally, when the upper portion 904 and lower portion 908 are joined, the striking face 920 overlaps at least a portion of the front perimeter 948. Finally, the upper portion 904 and lower portion 908 are joined such that the back edge 934 overlaps at least a portion of the rear perimeter 952.

[0219] 9C , the four perimeter portions of the lower portion 908 (front 948, rear 952, toe side 956, and heel side 960) combine with the upper portion 904 to form a sole 968. The sole 968 is perpendicular to a ground plane 972. The ground plane 972 contacts the sole 968 when the dual rail putter head 900 is in an address position to strike a golf ball. The sole 968 of the dual rail putter head 900 extends from a toe end 912 of the dual rail putter head 900 to a heel end 916 of the dual rail putter head 900.

[0220] In most embodiments, the sole 968 of the dual rail putter head 900 may be completely flat. In some embodiments, the sole 968 of the putter head 900 may have a slight arch in the heel-to-toe direction, where 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, where 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.

[0221] Referring to FIG. 9A, in one embodiment, the lower portion 908 can further comprise a front mass 941, a rear mass 943, a toe mass 945, and a heel mass 947. The front mass 941, the rear mass 943, the toe mass 945, and the heel mass 947 are integral to the lower portion 908. The front mass 941, the rear mass 943, the toe mass 945, and the heel mass 947 extend from the lower portion 908 in a direction away from the ground plane 972 and towards the upper portion 904. These mass portions provide a means for positioning and aligning the upper portion with the lower portion of the dual rail putter head 900. Additionally, these mass portions (i.e., the front mass 941, the rear mass 943, the toe mass 945, and the heel mass 947) provide an additional means for adding weight to the perimeter to increase the MOI of the putter over putters that do not have 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 can be of different weights within the ranges mentioned above. The mass features can 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 can each be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semicircular, square, cylindrical, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0222] In one embodiment, the front mass 941 is located on the front perimeter 948 and is equidistant from the toe side perimeter 956 and the heel side perimeter 960. However, in other embodiments, the front mass 941 may be located anywhere along the front perimeter 948. In one embodiment, the rear mass 943 is located on the rear perimeter 952 that is equidistant from the toe side perimeter 956 and the heel side perimeter 960. However, in other embodiments, the rear mass 943 may be located anywhere along the rear perimeter 952. In one embodiment, the toe mass 945 may be located at the junction of the toe side perimeter 956 and the rear perimeter 952. However, in other embodiments, the toe mass 945 may be located anywhere along the toe side perimeter 956. In one embodiment, the heel mass 947 may be located at the junction of the heel side perimeter 960 and the rear perimeter 952. However, in other embodiments, the heel mass 947 may be located anywhere along the heel side perimeter 960.

[0223] The front mass 941, rear mass 943, toe mass 945, and heel mass 947 provide areas of concentrated mass such that each mass 941, 943, 945, and 947 functions to increase the moment of inertia of the putter head 900. By locating each mass 941, 943, 945, and 947 on the perimeters 948, 952, 956, 960, each mass 941, 943, 945, and 947 increases the MOI because each mass is farther from the center of gravity of the putter 900. Each mass 941, 943, 945, and 947 on the perimeters 948, 952, 956, 960 is integrally formed from a second material, the second material being denser than the first material.

[0224] The front mass 941, rear mass 943, toe mass 945, and heel mass 947 serve two functions, as each mass 941, 943, 945, and 947 not only increases the MOI of the putter 900, but also provides an additional surface for the upper portion 904 to bond to the lower portion 908. Thus, the front mass 941 may also be referred to as the front bonded portion 941, the rear mass 943 may also be referred to as the rear bonded portion 943, the toe mass 945 may also be referred to as the toe bonded portion 945, and the heel mass 947 may also be referred to as the heel bonded portion 947.

[0225] Additionally, 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 over the toe mass 945 and the heel mass 947, respectively. The toe end cap 949 is adjacent to the toe end mid rail 936 and the back edge 934. The heel end cap 951 is adjacent to the heel end mid rail 940 and the back edge 934. In most embodiments, the toe end cap 949 and the heel end cap 951 include the same geometric shape, however, in some embodiments, the toe end cap 949 and the heel end cap 951 can include different geometric shapes.

[0226] 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 portion 904 is secured to the lower portion 908. Furthermore, when the upper portion 904 is secured to the lower portion 908, the toe end cap 949 is positioned such that the toe end cap 949 overlaps at least a portion of the toe side perimeter 956 and the toe mass 945. Furthermore, when the upper portion 904 is secured to the lower portion 908, the heel end cap 951 is positioned such that the heel end cap 951 covers at least a portion of the heel side perimeter 960 and the heel mass 960.

[0227] In some embodiments, the lower surface of the upper portion 904, the striking face 920, and the rear wall 932 can form a first cavity (not shown). The first cavity extends inwardly from the lower surface toward, 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 portion 908.

[0228] In some embodiments, the lower surface, the back edge 934, and the crown 942 form a second cavity (not shown). The second cavity extends inward from the lower 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 located equidistant between the toe end cap 949 and the heel end cap 951. The second cavity functions to receive the rear mass 943 of the lower portion 908.

[0229] The first and second cavities can include any desired geometric shape, however, in most embodiments, the first and second cavities include geometric shapes similar or identical to the geometric shapes of the front mass 941 and the rear mass 943. Furthermore, when the upper portion 904 is secured to the lower portion 908, the first cavity is positioned such that the first cavity surrounds the front mass 941 and the second cavity is positioned such that the second cavity surrounds the rear mass 943.

[0230] The combination of a lower density first material upper portion 904 and a higher density second material lower portion 908 creates a high MOI putter 900 without creating an excessively heavy putter. The large opening 964 formed by the perimeter portions 948, 952, 956, 960 of the lower portion 908 creates 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 (340 grams-385 grams).

[0231] The lower portion 908, in most embodiments, comprises less than 35% of the total volume of the putter 900. In some embodiments, the lower portion 908 comprises less than 34% of the total volume of the putter 900, less than 33% of the total volume of the putter 900, less than 32% of the total volume of the putter 900, less than 31% of the total volume of the putter 900, less than 30% of the total volume of the putter 900, less than 29% of the total volume of the putter 900, less than 28% of the total volume of the putter 900, or less than 27% of the total volume of the putter 900.

[0232] Although the lower portion 908 comprises less than half the volume of the putter 900, the lower portion 908 comprises at least 45% of the total mass of the putter 900. In some embodiments, the lower portion 908 comprises at least 46% of the mass of the putter 900, at least 46% of the mass of the putter 900, at least 46% of the mass of the putter 900, at least 47% of the mass of the putter 900, at least 48% of the mass of the putter 900, at least 49% of the mass of the putter 900, at least 50% of the mass of the putter 900, at least 51% of the mass of the putter 900, at least 52% of the mass of the putter 900, at least 53% of the mass of the putter 900, at least 54% of the mass of the putter 900, or at least 55% of the mass of the putter 900.

[0233] The beneficial shift of mass to the periphery of the putter head 900, through the use of a high density, low volume lower portion 908, increases the MOI of the putter 900 versus 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).

[0234] (h. Circular Embodiment) In another embodiment, the putter-type golf club head 1000 can be a circular putter head 1000. With reference to FIGS. 10A-10C, the circular putter head 1000 has an upper portion 1004 and a lower portion 1008. The lower portion 1008 is made from a first material having a first density, and the upper portion 1004 is made from a second material having a second density. The first density is less than the second density. The upper portion 1004 and the lower portion 1008 combine to create a high MOI putter head 1000 (5000 g·cm2-6500 g·cm2) while maintaining a desired volume and mass.

[0235] As described above, the upper portion 1004 is constructed from a high density material (i.e., the second material). The upper portion 1004 includes a toe end 1012, a heel end 1016, a hitting face 1020, a rear wall 1032, and a lower surface (not shown). The toe end 1012 is opposite the heel end 1016. The hitting 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 generally parallel to the hitting face 1020.

[0236] The upper portion 1004 further comprises a toe span 1056 and a heel span 1060. The toe span 1056 is adjacent to the toe end 1012 and opposite the heel span 1060. The heel span 1060 is also adjacent to the heel end 1016 and opposite the toe span 1056. In some embodiments, the heel span 1060 and the toe span 1056 can be parallel, but in some embodiments, the heel span 1060 and the toe span 1056 are not parallel. The toe span 1056 and the heel span 1060 extend in a direction away from the rear wall 1032 and the striking face 1020.

[0237] In most embodiments, the toe side span 1056 extends perpendicularly from the rear wall 1032 such that a right angle (90° angle) is formed at the junction of the toe side span 1056 and the rear wall 1032. However, in other embodiments, the toe side 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 side span 1056 and the rear wall 1032. Further, in most embodiments, the heel side span 1060 extends perpendicularly from the rear wall 1032 such that a right angle (90° angle) is formed at the junction of the heel side span 1060 and the rear wall 1032. However, in other embodiments, the heel side span 1060 can extend in any direction from the rear wall 1032 such that any angle (0°-180°) can be formed at the junction of the heel side span 1060 and the rear wall 1032.

[0238] 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 transfers most of the putter's volume and mass to the end of the top 1008. The gap 1064 can include any shape, but in one embodiment, the gap is approximately rectangular. In other embodiments, the gap 1064 may be circular, curvilinear, triangular, trapezoidal, parabolic, golf ball shaped, square, or any other desired geometric shape.

[0239] The lower portion 1008 of the putter head 1000 includes 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 is opposite the rear edge 1034. The toe edge 1034 is adjacent to the front edge 1041 and the rear edge 1034 and is opposite the heel edge 1045. Also, the heel edge 1045 is adjacent to the front edge 1041 and the rear edge 1034 and is opposite the toe edge 1043. In some embodiments, the toe edge 1043 and the heel edge 1045 can 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 can be parallel, but in some embodiments, the front edge 1041 and the rear edge 1034 are not parallel.

[0240] The front edge 1041, the rear edge 1034, the toe edge 1043, and the heel edge 1045 join to form an opening 1065. The opening 1065 is bounded by four edges: the front 1041, the rear 1034, the toe 1043, and the heel 1045. The four edges 1041, 1034, 1043, 1045 form a perimeter around the opening 1065.

[0241] In some embodiments, the opening 1065 formed by the front edge 1041, the rear edge 1034, the toe edge 1043, and the heel edge 1045 can be any one of the following shapes: rectangular, triangular, semicircular, circular (golf ball size), circular (larger than a golf ball), circular (smaller than a golf ball), square, oval, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0242] 10C, the lower portion 1008 is affixed to the upper portion 1004 such that a portion of the upper portion 1004 and the lower portion 1008 intersect with a ground plane 1072. The ground plane 1072 contacts the lower portion 1008 when the putter head 1000 is in an address position to strike a golf ball.

[0243] Additionally, the striking face 1020 of the putter head 1000 comprises a striking face center point 1076 and a loft plane 1080. The striking face center point 1076 is equidistant from the upper rail 1050 of the top 1004 and the ground plane 1072. 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. Additionally, a midplane 1084 intersects the striking face center point 1076 and is perpendicular to the loft plane 1080. Additionally, a y-axis 1088 intersects the midplane 1084 and is perpendicular to the ground plane 1072 .

[0244] When the upper portion 1004 and the lower portion 1008 are joined, the toe span 1056 overlaps at least a portion of the toe edge 1043. Additionally, when the upper portion 1004 and the lower portion 1008 are joined, the heel span 1060 overlaps at least a portion of the heel edge 1045. Additionally, when the upper portion 1004 and the lower portion 1008 are joined, the hitting face 1020 overlaps at least a portion of the front edge 1048. Finally, when the upper portion 1004 and the lower portion 1008 are joined such that the lower portion 1008 is secured to the hitting face 1020, the toe span 1056, and a portion of the heel span 1060, thereby filling at least a portion of the gap 1064 formed by the rear wall 1032, the toe span 1056, and the heel span 1060.

[0245] The lower portion 1008, together with the toe span 1056 and heel span 1060 of the upper portion 1004, form a sole 1068. The sole 1068 is perpendicular to a ground plane 1072, which is tangent to the sole 1068 when the putter head 1000 is in an address position to strike a golf ball. The sole 1068 of the putter head 1000 extends from the toe end 1012 of the putter head 1000 to the heel end 1016 of the putter head 1000.

[0246] In most embodiments, the sole 1068 of the putter head 1000 may be completely flat. In some embodiments, the sole 1068 of the putter head 1000 may have a slight arch in the direction from the heel 1016 to the toe 1012, where 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 the heel 1016 to the toe 1012, where 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.

[0247] In some embodiments, the upper portion 1004 can further comprise a crown (not shown). The crown extends from the striking face 1020 to a back edge 1034 of the lower portion 1008. The crown further extends from the striking face 1020 to the back edge 1034, covering at least a portion of the lower opening 1065 and covering at least a portion of the rear wall 1032.

[0248] The crown may 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 the inner 25% of the overall club head 1000 width and from the heel span 1060 to approximately the inner 25% of the overall club head 1000 width. In other embodiments, the crown may extend continuously or discontinuously across the overall width of the overall club head 1000 in a heel-to-toe direction. In some embodiments, the crown may extend less than 90% of the overall width of the club head 1000, less than 90% of the overall width of the club head 1000, less than 80% of the overall width of the club head 1000, less than 70% of the overall width of the club head 1000, less than 60% of the overall width of the club head 1000, less than 50% of the overall width of the club head 1000, less than 40% of the overall width of the club head 1000, or less than 30% of the overall width of the club head 1000. Additionally, in some embodiments, the crown can be substantially flat from the striking face 1020 to the back edge 1034, or 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, curvilinear, parabolic, sinusoidal, or polynomial function.

[0249] Additionally, the top 1004 of the putter head 1000 may include one or more alignment features 1044 on the toe span 1065 and the heel span 1060. The alignment features 1044 may be any one or combination of lines, a series of lines, milled troughs, circles, dashed lines, triangles, channels, or any other desired alignment features 1044. The alignment features 1044 may be evenly spaced throughout the toe span 1065 and the heel span 1060, a portion of the crown, or the entire crown. The alignment features 1044 extending along the toe span 1056 and the heel span 1060 function to provide the viewer with a visual alignment field that extends the width of a golf ball, from the rear wall 1032 to the back edge 1034 of the putter 1000. The purpose is to use these alignment features 1044 along the toe span 1056 and heel span 1060 and / or crown to align the entire putter 1000 to the golf ball.

[0250] The combination of a high density first material upper portion 1004 and a low density second material lower portion 1008 produces a high MOI putter 1000 without producing an excessively heavy putter. The large gap 1064 formed by the spans 1056, 1060 of the rear wall 1032 and upper portion 1004 creates 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 (340 grams-385 grams).

[0251] The beneficial shift of mass to the periphery of the putter head 1000 through the use of a high density upper portion 1004 and a low volume, low mass lower portion 1008 increases the MOI of the putter 1000 versus 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).

[0252] Substitution of one or more claim elements constitutes a rearrangement, not a prosthesis. Moreover, advantages, other advantages, and solutions to a problem have been described in connection with particular embodiments. However, the advantages, other advantages, and solutions to a problem, and any one or more elements that make any advantage, advantage, or solution occur or become apparent, do not constitute a critical, essential, or essential feature or element of any or all elements of a claim, unless such advantage, advantage, solution, or element is expressly recited in such claim.

[0253] Because the rules of golf change from time to time (e.g., new rules may be adopted, or old rules may be repealed or modified, by golf standards organizations and / or governing bodies such as the United States Golf Association (USGA), the Royal and American Golf Association (R&A), etc.), golf equipment related to the devices, methods and products described herein may or may not conform to the rules of golf at any particular time. Accordingly, golf equipment related to the devices, methods and products described herein may be advertised, offered for sale and / or sold as conforming or non-conforming golf equipment. The devices, methods and products described herein are not limited in this respect.

[0254] While the above examples may be described with respect to the putter-type golf clubs, devices, methods, and articles of manufacture described herein, the devices, methods, and articles of manufacture described herein may also be applicable to other types of sporting goods, such as hockey sticks, tennis racquets, fishing rods, ski poles, etc.

[0255] Furthermore, the embodiments and limitations described in this specification are not offered to the public under the doctrine of disclosure if the embodiments and / or limitations (1) are not explicitly claimed in the claims and (2) are equivalent or potentially equivalent to the express elements and / or limitations in the claims under the doctrine of equivalents.

[0256] Clause 1: A putter-type golf club head, comprising an upper portion and a lower portion, the upper portion made from a first material having a first density and the lower portion made from a second material having a second density, the first density being less than the second density, the lower portion comprising a front perimeter, a toe side perimeter, a heel side perimeter, and a rear perimeter, the lower portion further comprising an opening bounded by the front perimeter, the toe side perimeter, the heel side perimeter, and the rear perimeter, the upper portion comprising a heel end, a toe end, a striking face, a rear wall, a back edge, a crown, and a lower surface, the toe end being opposite the heel end and the back edge being opposite the striking face, the crown extending from the striking face to the back edge over at least a portion of the rear wall, and the lower surface extending from the striking face to the back edge. 16. A putter-type golf club head, comprising: a golf club head having a top end opposite a crown, the top end secured to the bottom end, the top end being further from a ground plane than the bottom end, the heel end overlying at least a portion of the heel side perimeter, the toe end overlying at least a portion of the toe side perimeter, the striking face overlying at least a portion of the front perimeter, the crown extending from the striking face to the rear perimeter, the bottom end and the top end joining to form a sole, the sole contacting the ground plane and the striking face contacting a loft plane forming a loft angle between the loft plane and the ground plane when the golf club head is in an address position, the bottom end comprising less than 30% of the volume of the golf club head and the bottom end comprising more than 50% of the mass of the golf club head.

[0257] Clause 2: The putter-type golf club head described in Clause 1, wherein the lower portion further comprises a toe mass at a junction of the toe side periphery and the rear periphery, a heel mass at a junction of the heel side periphery and the rear periphery, a rear mass located on the rear periphery and equidistant from the toe side periphery and the heel side periphery, and a front mass located on the front periphery and equidistant from the toe side periphery and the heel side periphery.

[0258] Clause 3: The putter-type golf club head of clause 2, wherein the toe mass, the heel mass, the rear mass, and the front mass are integral with the lower portion and extend from the lower portion in a direction away from the ground plane toward the upper portion.

[0259] Clause 4: The putter-type golf club head of 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.

[0260] Clause 5: The putter-type golf club head of clause 4, wherein the toe end cap is configured to mate with the toe mass and the heel end cap is configured to mate with the heel mass.

[0261] Clause 6: The putter-type golf club head of clause 5, wherein the upper portion further comprises a first cavity and a second cavity, the first cavity being formed in the underside surface between the striking face and the rear wall and extending in a direction toward the crown, and the rear opening being formed in the underside surface adjacent the back edge and equidistant from the toe end cap and the heel end cap.

[0262] Clause 7: The putter-type golf club head of clause 6, wherein the first cavity is configured to mate with the front mass and the second cavity is configured to mate with the rear mass.

[0263] Clause 8: The putter-type golf club head of clause 4, wherein the toe-end mid-rail and the heel-end mid-rail descend from the striking face to the rear perimeter.

[0264] Clause 9: The putter-type golf club head of clause 4, wherein the heel-end mid-rail and the toe-end mid-rail include one or more alignment features thereon.

[0265] Clause 10: The putter-type golf club head of clause 9, wherein the one or more alignment features can be evenly or unevenly spaced from the striking face to the rear perimeter.

[0266] Clause 11: The putter-type golf club head of clause 1, wherein the front perimeter of the lower portion has a front width measured from a junction of the toe side perimeter and the front perimeter to a junction of the heel side perimeter and the front perimeter.

[0267] Clause 12: The putter-type golf club head of clause 11, wherein the rear perimeter of the lower portion has a rear width measured from the junction of the toe side perimeter and the rear perimeter to the junction of the heel side perimeter and the rear perimeter.

[0268] Clause 13: The putter-type golf club head according to clause 12, wherein the front width is greater than the rear width.

[0269] Clause 14: The putter-type golf club head of clause 1, wherein the one or more alignment features are disposed on the crown.

[0270] Clause 15: The putter-type golf club head of clause 1, wherein the first density of the first material is less than 6.0 g / cc.

[0271] Clause 16: The putter-type golf club head of clause 1, wherein the second density of the second material is greater than 7.0 g / cc.

[0272] Clause 17: The putter-type golf club head of clause 1, wherein the second density of the second material is at least two times greater than the first density of the first material.

[0273] Clause 18: The putter type golf club head of clause 1, wherein the first material may comprise any one or combination of 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, 304 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, ADC-12, or any metal suitable for making a golf club head.

[0274] Clause 19: The putter type golf club head of clause 1, wherein the second material may comprise any one or combination of 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, 304 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, ADC-12, or any metal suitable for making a golf club head.

[0275] Clause 20: The putter-type golf club head of clause 1, wherein the first material is ADC-12 and the second material is 304 stainless steel.

Claims

1. A putter-type golf club head, It has an upper portion and a lower portion, the upper portion is made from a first material having a first density and the lower portion is made from a second material having a second density; the first density is less than the second density; the upper portion includes a toe end, a heel end, a striking face, a rear wall, a back edge, a crown, and a lower surface; the lower portion includes a front perimeter, a rear perimeter, a sole, a toe side wing, and a heel side wing, the toe side wing and the heel side wing extending beyond the rear wall of the upper portion; the rear perimeter, the toe side wing, and the heel side wing form a gap, the gap being bounded by the rear perimeter, the toe side wing, and the heel side wing; the lower portion further comprises a front toe mass and a front heel mass, the front toe mass and the front heel mass extending from the lower portion toward the upper portion; the lower surface, the striking face, and the rear wall of the upper portion define a first cavity proximate the toe end and a second cavity proximate the heel end, the first cavity and the second cavity extending inwardly from the lower surface toward but not reaching the crown; the front toe mass and the front heel mass are configured to mate with the first cavity and the second cavity, respectively; Putter type golf club head.

2. 2. The putter-type golf club head of claim 1, wherein the toe side wing and the heel side wing extend perpendicularly from the rear perimeter such that a first right angle is formed at the juncture of the toe side wing and the rear perimeter and a second right angle is formed at the juncture of the heel side wing and the rear perimeter.

3. The putter-type golf club head of claim 1 , wherein the crown extends away from the striking face, beyond the front perimeter of the lower portion, to the back edge of the upper portion.

4. the crown further comprises an alignment trough; The alignment trough comprises: adjacent the rear wall and generally perpendicular to the striking face; The putter-type golf club head of claim 1 bounded by the back edge, the rear wall, and the crown.

5. 5. The putter-type golf club head of claim 4, wherein the alignment trough has a width of approximately 4.27 cm.

6. Further having a volume and a mass, The putter-type golf club head of claim 1 , wherein the lower portion comprises less than 40% of the volume of the putter-type golf club head and at least 45% of the mass of the putter-type golf club head.

7. 2. The putter-type golf club head according to claim 1, having a moment of inertia between 5000 g·cm 2 and 6500 g·cm 2 in a direction from the heel end to the toe end.

8. the first cavity is positioned such that the first cavity surrounds the front toe mass, and the second cavity is positioned such that the second cavity surrounds the front heel mass; The putter-type golf club head of claim 1 , wherein the first cavity and the second cavity are geometrically complementary to the front toe mass and the front heel mass, respectively.

9. The putter-type golf club head of claim 1 , wherein said front toe mass and said front heel mass are integral with said lower portion.

10. The putter-type golf club head of claim 1, wherein the first material is comprised of any one or combination of the following: 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, 304 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, or ADC-12.

11. The putter-type golf club head of claim 1, wherein the second material is comprised of any one or combination of the following: 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, 304 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, or ADC-12.

12. The putter-type golf club head of claim 1 , wherein the first density of the first material is less than 6.0 g / cc.

13. The putter-type golf club head of claim 1 , wherein the second density of the second material is greater than or equal to 7.0 g / cc.

14. 10. The putter-type golf club head of claim 1, wherein the upper and lower portions are joined by any method or combination of: welding, soldering, brazing, staking, adhesive, epoxy, or mechanical fastening.

15. It also has a toe wing mass and a heel wing mass. the toe wing mass extends from the lower portion toward the upper portion and is disposed along at least a portion of the toe wing; The putter-type golf club head of claim 1 , wherein the heel wing mass extends from the lower portion toward the upper portion and is disposed along at least a portion of the heel wing.

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