Multi-component putter

Abstract

Embodiments of multi-component putters comprising an upper portion and a lower portion are described herein. The upper portion is formed from a first material having a first density and the lower portion is formed from a second material having a second density. The first density is less than the second density. The upper portion is affixed to the lower portion via an adhesive or a combination of adhesives and interlocking geometry. The multi-component putter design provides increased forgiveness and moment of inertia compared to a putter formed from a single material.

Description

TECHNICAL FIELD

[0001] This disclosure relates generally to golf clubs and relates more particularly to a multi-component putter type golf club head.BACKGROUND

[0002] In many putter-type golf club heads, weight distribution is used to vary 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 faceplate inserts, inserts for the back of portion of the face, and attachments for the outer perimeter of the toe and heel regions. In particular putter-type golf club heads, often use weight ports in the heel and toe regions that can be removably attached by a fastener, or permanently attached through a variety of epoxies, glues, or machining methods. The use of weight ports in the heel and toe regions, the increases the MOI in the putter head, thereby producing a straighter ball path after impact.

[0003] Although these weight ports in the heel and toe regions increase MOI, they increase the weight of the golf club head and can make the golf club head heavier than an ideal weight for a putter. In addition, installing weight ports into a golf club putter head requires a cavity or recess to place these weight ports into the putter head during manufacturing, thereby increasing the cost of that putter head. Additionally, the weight ports can cause vibrations within the cavity or recess during impact, when the golf club head contacts a golf ball. These cavities and recesses can cause the sound of the club head to change as well, creating a hollow sound within the club head.

[0004] A putter-type golf club head including an upper portion forming part of the crown and the sole, and comprising a strike face, is known from US 2007 / 0238547 A1. In the known structure, the upper portion comprises a forward portion and a rearward extension, and the lower portion comprises toe and heel mass portions, wherein the lower portion is configured to receive the upper portion such that the rearward extension is positioned above a central portion and between the toe and heel mass portions.

[0005] There is a need in the art to develop a putter having a desirable sound, perimeter weighting, and an ideal weight for balanced putting while being pleasing to the eye of the user to create repeatability for a putt.SUMMARY OF THE INVENTION

[0006] The invention is defined by the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A illustrates an exploded view of a blade putter type golf club head. FIG. 1B illustrates an isometric view of the blade putter type golf club head of FIG. 1A. FIG. 1C illustrates a side view of the blade putter type golf club head of FIG. 1A. FIG. 2A illustrates an exploded view of a blade putter type golf club head. FIG. 2B illustrates an isometric view of the blade putter type golf club head of FIG. 2A. FIG. 2C illustrates a side view of the blade putter type golf club head of FIG. 2A. FIG. 3A illustrates an exploded view of a crescent putter type golf club head. FIG. 3B illustrates an isometric view of the crescent putter type golf club head of FIG. 3A. FIG. 3C illustrates a side view of the crescent putter type golf club head of FIG. 3A. FIG. 4A illustrates an exploded view of a semi-circular putter type golf club head. FIG. 4B illustrates an isometric view of the semi-circular putter type golf club head of FIG. 4A. FIG. 4C illustrates a side view of the semi-circular putter type golf club head of FIG. 4A. FIG. 5A illustrates an exploded view of another semi-circular putter type golf club head. FIG. 5B illustrates an isometric view of the semi-circular putter type golf club head of FIG. 5A. FIG. 5C illustrates a side view of the semi-circular putter type golf club head of FIG. 5A. FIG. 6A illustrates an exploded view of a winged putter type golf club head. FIG. 6B illustrates an isometric view of the winged putter type golf club head of FIG. 6A. FIG. 6C illustrates a side view of the winged putter type golf club head of FIG. 6A. FIG. 7A illustrates an exploded view of a spade putter type golf club head. FIG. 7B illustrates an isometric view of the spade putter type golf club head of FIG. 7A. FIG. 7C illustrates a side view of the spade putter type golf club head of FIG. 7A. FIG. 7D illustrates a bottom perspective view of the spade putter type golf club head of FIG. 7A. FIG. 8A illustrates an exploded view of a T-shaped putter type golf club head with periphery spans. FIG. 8B illustrates an isometric view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 8C illustrates a side view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 8D illustrates a bottom perspective view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 9A illustrates an exploded view of a dual rail putter type golf club head. FIG. 9B illustrates an isometric view of the dual rail putter type golf club head of FIG. 9A. FIG. 9C illustrates a side view of the dual rail putter type golf club head of FIG. 9A. FIG. 9D illustrates a bottom perspective view of the dual rail putter type golf club head of FIG. 9A. FIG. 10A illustrates an exploded view of a circular putter type golf club head. FIG. 10B illustrates an isometric view of the circular putter type golf club head of FIG. 10A. FIG. 10C illustrates a side view of the circular putter type golf club head of FIG. 10A. FIG. 10D illustrates a bottom perspective view of the circular putter type golf club head of FIG. 10A. FIG. 11A illustrates an exploded view of a putter type golf club head comprising a strike face insert having a single component system. FIG. 11B illustrates an exploded view of a putter type golf club head comprising a strike face having a two-component system. FIG. 11C illustrates a front view of a putter type golf club head comprising a strike face insert according to a third embodiment. FIG. 12A illustrates a top perspective view of a two-part putter type club head comprising a sole plate. FIG. 12B illustrates a sole view of the two-part putter of FIG. 12A. FIG. 12C illustrates an exploded view of the two-part putter of FIG. 12A. FIG. 12D illustrates a bottom view of the two-part putter of FIG. 12A with the lower portion removed. FIG. 12E illustrates a heel view of the two-part putter of FIG. 12A. FIG. 13A illustrates a rear perspective view of a two-part putter type club head comprising a pocket. FIG. 13B illustrates an exploded view of the two-part putter of FIG. 13A. FIG. 13C illustrates a sole view of the two-part putter of FIG. 13A. FIG. 13D illustrates a heel view of the two-part putter of FIG. 13A with the lower portion removed. FIG. 13E illustrates a toe view of the two-part putter of FIG. 13A with the lower portion removed. FIG. 14A illustrates a top perspective view of a two-part putter head comprising a ball retrieval feature according to a first embodiment. FIG. 14B illustrates a bottom perspective view of the putter head of FIG. 14A. FIG. 14C illustrates an exploded view of the putter head of FIG. 14A. FIG. 14D illustrates an exploded view of the putter head of FIG. 14A. FIG. 14E illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a second embodiment. FIG. 14F illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a third embodiment. FIG. 14G illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a fourth embodiment. FIG. 14H illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a fifth embodiment. FIG. 15A illustrates a rear perspective view of a two-part putter head comprising a ball-outlining alignment aid. FIG. 15B illustrates a rear perspective exploded view of the two-part putter head of FIG. 15A. FIG. 15C illustrates a bottom view of the two-part putter head of FIG. 15A. FIG. 15D illustrates a top view of the two-part putter head comprising the ball-outlining alignment aid of FIG. 15A. FIG. 15E illustrates a top view of the two-part putter head comprising a ball-outlining alignment aid according to a second embodiment. FIG. 15F illustrates a top view of the two-part putter head comprising a ball-outlining alignment aid according to a third embodiment. FIG. 16A illustrates a front perspective view of a putter head comprising a separate toe mass and heel mass. FIG. 16B illustrates a rear perspective exploded view of the putter head of FIG. 16A. FIG. 16C illustrates a sole view of the putter head of FIG. 16A. FIG. 16D illustrates a bottom view of the toe mass and heel mass of the putter head of FIG. 16A. FIG. 17A illustrates a rear perspective exploded view of a two-part blade-type putter head according to a first embodiment. FIG. 17B illustrates a rear perspective exploded view of a two-part blade-type putter head according to a second embodiment with an aperture through the strike face. FIG. 17C illustrates a rear perspective view of the two-part blade-type putter head of FIG. 17A. FIG. 17D illustrates a front perspective view of the upper portion of the two-part blade-type putter head of FIG. 17A. FIG. 17E illustrates a front perspective view of the two-part blade-type putter head of FIG. 17B. FIG. 18A illustrates a rear perspective exploded view of a three-part putter head according to one embodiment. FIG. 18B illustrates a rear perspective view of the three-part putter head of FIG. 18A. FIG. 18C illustrates a bottom perspective view of the three-part putter head of FIG. 18A with the lower portion removed. FIG. 18D illustrates a sole view of the three-part putter head of FIG. 18A.

[0008] Figures 1 to 14, 17 and 18 are provided for explanation only. Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.DESCRIPTIONI. Putter Golf Club Head

[0009] Described herein is a two-part putter head having an upper portion made of a first material such as low density metal (i.e., aluminum, but not limited to) and a lower portion made of a second material, such as a high density metal (i.e., steel, but not limited to). The upper portion has a crown that spans from a strike face to a back edge. This upper portion is affixed to the lower portion and is farther from a ground plane than the lower portion. The lower portion, in most embodiments, has less than 35% of the total solid volume of the putter head, but greater than 45% of the mass. The lower portion provides a peripheral construction and a sole. This combination of peripheral construction and high density lower portion, results in an increase in MOI of at least 30%, over a putter with the same volume, mass, and single material construction (i.e., a putter milled of a single material such as a steel putter or a putter investment cast of a single material).

[0010] The lower portion of the two-part putter head further comprises a sole plate. The sole plate is formed from a high-density material. As described in more detail below, the two-part putter head includes the upper portion and the lower portion comprising the sole plate. The lower portion comprising the sole plate comprises mass structures, ball retrieval features, and / or ball outlining alignment aids to improve the putter experience. The putter heads including the upper portion and the lower portion comprising the sole plate provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye. The putter heads including the upper portion and the lower portion comprising the sole plate further provides consistent ball speed and ball travel distance for repeated putts.

[0011] The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0012] The terms "left," "right," "front," "back," "upper," "lower," "over," "under," "top," "bottom," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the apparatus, methods, and / or articles of manufacture described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

[0013] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.

[0014] In many embodiments, the golf club head can comprise a putter-type golf club head (the putter type golf club head 100, 200, 300 400 ... etc.). FIGS. 1-12B illustrate multiple embodiments of a putter-type golf club head having an upper portion and lower portion that are separately made of different materials and coupled together and provided for explanation only to aid an understanding of the invention. The putter-type golf club head can be a mallet-type putter head, 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.

[0015] In many embodiments, the putter-type golf club head can have a loft angle less than 10 degrees. In many embodiments, the loft angle of the club head can be between 0 and 5 degrees, between 0 and 6 degrees, between 0 and 7 degrees, or between 0 and 8 degrees. For example, the loft angle of the club head can be less than 10 degrees, less than 9 degrees, less than 8 degrees, less than 7 degrees, less than 6 degrees, or less than 5 degrees. For 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.

[0016] The putter-type golf club head comprises an upper portion and a lower portion. The golf club head can comprise a toe end and a heel end opposite the toe end. The putter-type golf club head can comprise a strike face. The putter-type golf club head can comprise a rear wall opposite the strike face. Further, the putter-type golf club head can comprise an alignment feature. Furthermore, the putter-type golf club head can comprise 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.

[0017] The upper portion is made of a first material. The lower portion is made of a second material. The first material is different than 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.

[0018] In many embodiments, the putter-type golf club head can have a mass that ranges between 340 and 385 grams. In other embodiments, the mass of the putter-type golf club head can range between 340 grams - 345 grams, 345 grams - 350 grams, 350 grams - 355 grams, 355 grams - 360 grams, 360 grams - 365 grams, 365 grams - 370 grams, 370 grams - 375 grams, 375 grams - 380 grams, or 380 grams - 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, 380 grams, 381 grams, 382 grams, 383 grams, 384 grams, or 385 grams.

[0019] In many embodiments, the putter type golf club head can comprise a club head volume ranging between 25 cc and 125 cc. In some embodiments, the club head volume can range between 25 cc - 30 cc, 30 cc - 35 cc, 35 cc - 40 cc, 40 cc - 45 cc, 45 cc - 50 cc, 50 cc - 55 cc, 55 cc - 60 cc, 60 cc - 65 cc, 65 cc - 70 cc, 70 cc - 75 cc, 75 cc - 80 cc, 80 cc - 85 cc, 85 cc - 90 cc, 90 cc - 95 cc, 95 cc - 100 cc, 100 cc - 105 cc, 105 cc - 110 cc, 110 cc - 115 cc, 115 cc - 120 cc, or 120 cc - 125 cc. In one embodiment, the club head volume can range between 40 cc - 110 cc. In some embodiments, the club head volume can be greater than 25 cc, greater than 50 cc, greater than 75 cc, or greater than 100 cc.

[0020] In some embodiments, the putter type golf club head can comprise a strike face made of the first material. In other embodiments, the strike face can be made of the second material. In these embodiments, the material of the strike face can be 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 any metal suitable for creating a golf club head. According to the invention, the strike face is integrally formed to the upper portion. In other examples useful for understanding the invention, but which are not covered by the appended claims, the strike face can be integrally formed to the lower portion. The strike face can be integrally formed to the club head by co-molding, injection molding, casting, additive manufacturing or other forming process.

[0021] FIGS. 11A - 11C illustrate various strike face features 1100 used on the multi-component putters described in this disclosure for information only and to aid a general understanding of the invention. As described in more detail below, the strike face features 1100 can comprise a single component system, a two-component system, or a single component system in combination with a metal portion. The single component system comprises a single strike face insert or component. The two-component system comprises multiple strike face inserts or components. In many embodiments, the strike face features 1100 can comprise a strike face insert. In these embodiments, the strike face is independently formed prior to being coupled to the club head. The side of the strike face insert that will contact the club head can comprise geometry complementary to the geometry of the corresponding portion of the club head that will contact the strike face. In some embodiments, the strike face insert can be made of the first material or the second material. In other embodiments, the strike face insert can be made of a third material. In some embodiments, the strike face insert can be integrally formed with the upper portion or the lower portion. In other embodiments, the strike face insert can be separately formed from both the upper portion and the lower portion.

[0022] The strike face can be secured to the club head by being integrally formed to a portion of the club head or by a fastening means. In some embodiments, the strike face is secured to the upper portion. In these embodiments, the upper portion defines an insert cavity 1110 in a forward portion of the upper portion. The upper portion insert cavity 1110 is configured to receive the strike face insert. Further, in these embodiments, when the strike face insert is affixed to the upper portion, the upper portion encompasses and mates with the insert cavity 1110. In other embodiments, the strike face can be secured to the lower portion. In these embodiments, the lower portion can comprise an insert cavity (not shown). The lower portion insert cavity functions to receive the strike face insert. Further, in these embodiments, when the insert is affixed to the lower portion, the lower portion encompasses and mates with the insert cavity. The strike face can be secured by an adhesive such as glue, very high bond (VHB ™< ) tape, epoxy or another adhesive. Alternately or additionally, the strike face can be secured by welding, soldering, screws, rivets, pins, mechanical interlock structure, or another fastening method.

[0023] The strike face insert can comprise any one or layered combination of the following: aluminum, stainless steel, copper, thermoplastic co-polyester elastomer (TPC), thermoplastic elastomer (TPE), thermoplastic urethane (TPU), steel, nickel, TPU / aluminum, TPE / aluminum, plastic / metal screen insert, polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, PEBAX ®< , or any other desired material. PEBAX ®< is a polyether block amide that is a thermoplastic elastomer made of a flexible polyether and rigid polyamide. The rigid polyamide can comprise Nylon. The PEBAX ®< can comprise different compounds that correspond to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, the PEBAX ®< can comprise a PEBAX ®< 4033 (Arkema, Paris France) or a PEBAX ®< 6333 (Arkema, Paris France). The PEBAX ®< 4033 (Arkema, Paris France) comprises a tetramethylene oxide (53% wt) and a Nylon 12. The PEBAX ®< 6333 (Arkema, Paris France) comprises a Nylon 11. In some embodiments, the face insert can comprise a material such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials or any combination thereof.

[0024] The PEBAX ®< can comprise a percentage of polyether by volume. In some embodiments, the PEBAX ®< can comprise 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 30% to 50%, 30% to 60%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% polyether by volume. For example, the PEBAX ®< can comprise 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% of polyether by volume. In some embodiments, the PEBAX ®< can comprise 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% of polyamide by volume. For example, the PEBAX ®< can comprise 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% of polyamide by volume. As the percentage of polyether percentage increases, the hardness of the PEBAX ®< decreases. As the percentage of polyamide percentage increases, the hardness of the PEBAX ®< increases. For example, the PEBAX ®< 4033 (Arkema, Paris France) can comprise 40% to 60% polyether by volume and 15% to 30% polyamide by volume. For example, the PEBAX ®< 6333 (Arkema, Paris France) can comprise 15% to 30% polyether by volume and 40% to 60% polyamide by volume.

[0025] In many embodiments, the PEBAX ®< can comprise a hardness ranging from Shore 25D to Shore 75D. In some embodiments, the hardness of the PEBAX can range from Shore 25D to Shore 35D, Shore 35D to Shore 45D, Shore 36D to Shore 44D, Shore 38D to Shore 42D, Shore 45D to Shore 55D, Shore 55D to Shore 65D, Shore 56D to Shore 64D, Shore 60D to Shore 65D, or Shore 65D to Shore 75D. For example, the hardness of the PEBAX can be Shore D 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70.

[0026] In many embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a lower hardness than the PEBAX ®< 6333 (Arkema, Paris France). In many embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a hardness range of Shore 35D to Shore 55D. In some embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a hardness range of Shore 38D to Shore 42D, or Shore 39D to Shore 41D. For example, the PEBAX ®< 4033 (Arkema, Paris France) can be comprise a Shore D hardness of 40. In many embodiments, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a hardness range of Shore 50D to Shore 75D. In some embodiments, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a hardness range of Shore 55D to Shore 70D, or Shore 60D to Shore 65D. For example, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a Shore D hardness of 63.

[0027] As illustrated in FIG. 11A, the strike face features 1100 can comprise a strike face insert system 1120. The strike face insert system 1120 can be a single component system comprising a ball striking layer 1122 and an adhesive layer 1124. The strike face insert 1120 is configured to be adhered into the insert cavity 1110 via the adhesive layer 1124. The strike face insert 1120 can comprise a polymer type material as described in this disclosure. The strike face insert 1120 can comprise a PEBAX ®< as described in this disclosure.

[0028] As illustrated in FIG. 11B, the strike face features 1100 can comprise a strike face insert system 1130. The strike face insert system 1130 can be a two-component system comprising a ball striking face plate 1132 and a face insert base 1134. The strike face insert 1130 having the two-component system is configured to be received in the insert cavity 1110 via one or more adhesive layers. The ball striking face plate 1132 of the strike face insert 1130 can comprise a first insert material. The face insert base 1134 of the strike face insert 1130 can comprise a second insert material. In many embodiments, the first insert material of the ball striking face plate 1132 and the second material of the face insert base 1134 can be different. In some embodiments, the first insert material of the ball striking face plate 1132 and the second insert material of the face insert base 1134 can be similar. In many embodiments, the first insert material of the ball striking face plate 1122 can comprise a polymer type material. In some embodiments, the first insert material of the ball striking face plate 1122 can comprise a metallic material. In many embodiments, the second insert material of the face insert base 1134 can comprise a polymer type material.

[0029] The first insert material can comprise a metal such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials or any combination thereof.

[0030] The first insert material or the second insert material can comprise a polymer type material. The polymer type material can comprise polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, or any other polymer type material. In many embodiments, the face insert can comprise a PEBAX ®< . More specifically, the PEBAX ®< is a polyether block amide that is a thermoplastic elastomer made of a flexible polyether and rigid polyamide. The rigid polyamide can comprise Nylon. The PEBAX ®< can comprise different compounds that correspond to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, the PEBAX ®< can comprise a PEBAX ®< 4033 (Arkema, Paris France) or a PEBAX ®< 6333 (Arkema, Paris France). The PEBAX ®< 4033 (Arkema, Paris France) comprises a tetramethylene oxide (53% wt) and a Nylon 12. The PEBAX ®< 6333 (Arkema, Paris France) comprises a Nylon 11. The first insert material and the second insert material can comprise similar polyether percentages, polyamide percentages, or Shore D hardness values as described above.

[0031] The ball striking face plate 1132 of the strike face insert 1130 can comprise a thickness. In many embodiments, the thickness of the ball striking face plate 1132 can range from 0.381mm to 2.921mm (0.015 to 0.115 inch). In some embodiments, the thickness of the ball striking face plate 1132 can range from 0.381mm to 1.143mm (0.015 to 0.045 inch), 0.508mm to 1.27mm (0.020 to 0.050 inch), 0.635mm to 1.397mm (0.025 to 0.055 inch), 1.27mm to 2.54mm (0.050 to 0.100 inch), 1.397mm to 2.667mm (0.055 to 0.105 inch), 1.524 to 2.794mm (0.060 to 0.110), or 1.651mm to 2.921mm (0.065 to 0.115 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be at least 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be greater than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be less than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). For example, the thickness of the ball striking face plate 1132 can be 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch).

[0032] In other embodiments, the thickness of the ball striking face plate 1132 can range from 2.921mm to 10.16mm (0.115 to 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can range from 2.921mm to 5.08mm (0.115 to 0.20 inch), 3.81mm to 7.62mm (0.15 to 0.30 inch), 5.08mm to 7.62mm (0.20 to 0.30 inch), 6.35 to 8.89mm (0.25 to 0.35 inch), or 7.62mm to 10.16mm (0.30 to 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be at least 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be greater than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be less than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). For example, the thickness of the ball striking face plate 1132 can be 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch).

[0033] The face insert base 1134 of the strike face insert 1130 can comprise a thickness. In many embodiments, the thickness of the face insert base 1134 can range from 1.27mm to 5.08mm (0.05 to 0.20 inch). In some embodiment, the thickness of the face insert base 1134 can range from 1.27mm to 2.54mm (0.05 to 0.10 inch), or 2.54mm to 5.08mm (0.10 to 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be at least 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be greater than or equal to 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be less than or equal to 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). For example, the thickness of the face insert base 1134 can be 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch).

[0034] In other embodiments, the thickness of the face insert base 1134 can range from 5.08mm to 20.32mm (0.20 to 0.80 inch). In some embodiments, the thickness of the face insert base 1134 can range from 5.08mm to 12.7mm (0.20 to 0.50 inch), 7.62mm to 15.24mm (0.30 to 0.60 inch), 10.16mm to 17.78mm (0.40 to 0.70 inch), or 12.7mm to 20.32mm (0.50 to 0.80 inch). In some embodiment, the thickness of the face insert base 1134 can range from 5.08mm to 10.16mm (0.20 to 0.40 inch), 7.62mm to 12.7mm (0.30 to 0.50 inch), 10.16mm to 15.24mm (0.40 to 0.60 inch), 12.7mm to 17.78mm (0.50 to 0.70 inch), or 15.24mm to 20.32mm (0.60 to 0.80 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be at least 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be greater than or equal to 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be less than or equal to 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). For example, the thickness of the face insert base 1134 can be 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch).

[0035] As illustrated FIG. 11C, the strike face features 1100 can comprise a strike face insert system 1140. The strike face insert system 1140 comprise a strike face insert 1144 and a metal portion 1142. The strike face insert 1144 comprises a single component system described above. The metal portion 1142 surrounds the strike face insert 1144. The strike face insert 1144 can be formed from a polymer material described in this disclosure. The strike face insert 1144 is further surrounded by an epoxy border 1146. The epoxy border 1146 extends around a perimeter of the strike face insert 1144. The combination of the strike face insert 1144 formed from a polymer type material and the epoxy border 1146 can provide enhanced feel and sound during impacts with a golf ball. Further, removing material from the strike face or the upper portion to accommodate the strike face insert 1144 reduces the putter head weight at or near a center area of the putter head. Removing material from the center area and / or forward area of the putter head allows for more weight to be positioned in the perimeter of the putter head thereby increasing moment of inertia and forgiveness.

[0036] The epoxy border 1146 surrounding the strike face insert 1144 can comprise a width. The width of the epoxy border 1146 can be measured as a transverse width. In many embodiments, the width of the epoxy border can range from 0.254mm to 2.032mm (0.01 inch to 0.08 inch). In some embodiments, the width of the epoxy border 1146 can range from 0.254mm to 1.016mm (0.01 inch to 0.04 inch), or 1.016mm to 2.032mm (0.04 inch to 0.08 inch). In some embodiments, the width of the epoxy border 1146 can range from 0.508mm to 1.27mm (0.02 inch to 0.05 inch), 0.762mm to 1.524mm (0.03 inch to 0.06 inch), 1.016mm to 1.778mm (0.04 inch to 0.07 inch), or 1.27mm to 1.778mm (0.05 inch to 0.07 inch). For example, the width of the epoxy border can be 0.254, 0.508, 0.762, 0.889, 1.016, 1.143, 1.27, 1.524, 1.778, or 2.032 mm (0.01, 0.02, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, or 0.08 inch). In one example, the width of the epoxy border 1146 can be 0.762mm (0.03 inch).

[0037] The metal portion 1142 can further comprise a milling pattern 1148. The milling pattern 1148 can comprise a plurality of milling lines that extend in a vertical, horizontal, curvilinear, arcuate, or circular direction across the strike face. The milling pattern 1148 can extend in a crown to sole direction, and / or in a heel to toe direction across the strike face. The milling pattern 1148 enhances the surface finish of the putter head or strike face to improve the appearance of the putter head.

[0038] The strike face insert systems (1120, 1130, 1140) described in this disclosure can be formed by a number of different processes. The different forming processes include the following: injection molding, casting, blow molding, compression molding, co-molding, laser forming, film insert molding, gas assist molding, rotational molding, thermoforming, laser cutting, 3-D printing, forging, stamping, electroforming, machining, molding, or any combination thereof. Further, the strike face insert can have any combination of hardness, volume, thickness, and forming processes described above.

[0039] In many embodiments, the upper portion of the putter-type golf club head having the first material comprises a first density ranging between 1.0 g / cc and 6.0 g / cc. The first density can range between 2.0 g / cc to 5.0 g / cc. In some embodiments, the first density can range between 1.0 - 1.25 g / cc, 1.25 - 1.5 g / cc, 1.5 - 1.75 g / cc, 1.75 - 2.0 g / cc, 2.0 - 2.25 g / cc, 2.25 - 2.5 g / cc, 2.5 - 2.75 g / cc, 2.75 - 3.0 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, 4.25 - 4.5 g / cc, 4.5 - 4.75 g / cc, 4.75 - 5.0 g / cc, 5.0 - 5.25 g / cc, 5.0 - 5.25 g / cc, 5.25 - 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 range between 2.0 - 3.0 g / cc. In some embodiments, the first density can be less 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, or 6.0 g / cc.

[0040] In many embodiments, the lower portion of the putter-type golf club head having the second material. The second material can comprise a density. The density is a second density to the first density of the first material in the upper portion. The second density of the second material of the lower portion can range between 7.0 g / cc and 20.0 g / cc. In some embodiments, the second density can range between 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 - 15.5 g / cc, 15.5 - 16.0 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 range between 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 2 times greater than the first density, at least 3 times greater than the first density, at least 4 times greater than the first density, or at least 5 times greater than 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.

[0041] The upper portion of the putter-type golf club having the first material can 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 any metal suitable for creating a golf club head. In many embodiments, the upper portion is made of aluminum alloy or ADC-12.

[0042] The lower portion of the putter-type golf club having the second material can 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 any metal suitable for creating a golf club head. 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 and upper portion are not made from the same one material or the same combination of materials.

[0043] Furthermore, the upper and lower portion of the putter-type golf club head can be joined in any one or combination of the following methods: welding, soldering, brazing, swedging, adhesion, epoxy, or mechanical fastening. In some embodiments, the upper and lower portion can be joined by adhesion with epoxy, polyurethanes, resins, hot melts, or any other adhesive.II. Embodiments a. Blade Embodiment

[0044] Referring to FIGS. 1A and 1B, a blade type putter head 100 is shown for information only and to aid a general understanding of the invention. The putter head 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 lower portion 108 combine to create a balanced putter head 100, while maintaining a desirable volume and mass.b. Blade Embodiment with Heel and Toe Mass

[0045] Referring to FIGS. 17A-17E, a blade type putter head 1700 is shown for explanation only to aid an understanding of the invention and has an upper portion 1704 and a lower portion 1708. The upper portion 1704 is made from a first material having a first density and the lower portion 1708 is made from a second material having a second density. The first density is less than the second density. The two-part blade type putter head 1700 is formed by an upper portion 1704 that overlays the back end of the lower portion 1708 without disturbing the strike face 1720. The upper portion 1704 and lower portion 1708 combine to create a balanced putter head 1700 with a high moment of inertia (3500 g·cm 2< - 5000 g·cm 2< ), while maintaining a desirable volume and mass.c. Crescent Embodiment

[0046] Referring to FIG. 3A-3C, a crescent-shaped putter head 300 is shown for explanation only to aid an understanding of the invention and has a upper portion 304 and a lower portion 308. The upper portion 304 is made from a first material have 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 lower portion 308 combine to create a balanced putter head 300, while maintaining a desirable volume and mass. The high density lower portion 308 and low density upper portion 308, place more mass near the peripheries of the putter head 300, thus increasing the MOI and stability over a putter with the same volume, mass, and single material construction.d. Semi-Circular Embodiment

[0047] Referring to FIG. 4A-4C, a semi-circular putter head 400 is shown for explanation only to aid an understanding of the invention and has an upper portion 404 and a lower portion 408. The upper portion 404 is made from a first material have 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 lower portion 408 combine to create a high-MOI putter head 400 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.e. Winged Embodiment

[0048] Referring to FIG. 6A and 6B, a winged shaped putter head 600 is shown for explanation only to aid an understanding of the invention and has a upper portion 604 and a lower portion 608. The upper portion 604 is made from a first material have 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 lower portion 608 combine to create a high-MOI putter head 600 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.f. Spade Embodiment

[0049] Referring to FIG. 7A and 7B, a spade shaped putter head 700 is shown for explanation only to aid an understanding of the invention and has a upper portion 704 and a lower portion 708. The upper portion 704 is made from a first material have 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 lower portion 708 combine to create a high-MOI putter head 700 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.g. T-Shaped Embodiment with Periphery Spans

[0050] Referring to FIGS. 8A and 8B, a T-shaped putter head with periphery spans 800 is shown for explanation only to aid an understanding of the invention, and has a upper portion 804 and a lower portion 808. The upper portion 804 is made from a first material have 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 lower portion 808 combine to create a high-MOI putter head 800 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.h. Dual-Rail Embodiment

[0051] Referring to FIGS. 9A and 9B, a dual-rail putter head 900 is shown for explanation only to aid an understanding of the invention and has a upper portion 904 and a lower portion 908. The upper portion 904 is made from a first material have 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 lower portion 908 combine to create a high-MOI putter head 900 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.i. Circular Embodiment

[0052] Referring to FIG. 10A-10C, a circular putter head 1000 is shown for explanation only to aid an understanding of the invention and has an upper portion 1004 and a lower portion 1008. The lower portion 1008 is made from a first material have 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 lower portion 1008 combine to create a high-MOI putter head 1000 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.III. Sole Plate Embodiments

[0053] Described below for information only and to aid an understanding of the invention are additional multi-component putter heads comprising an upper portion and a lower portion. The lower portion further comprises a sole plate formed from a high-density material, and the upper portion is formed from a low-density material. The material density of the upper portion is less than the material density of the lower portion including the sole plate. The sole plates described below comprise mass structures, ball retrieval features, and / or ball outlining alignment aids to provide more consistent and more forgiving putts. As described below, the putter heads including the upper portion and the lower portion comprising the sole plate provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye to create a consistent putting stroke. Further, the putter heads including the upper portion and the lower portion comprising the sole plate provides consistent ball speed and ball travel distance for repeated putts.a. Putter Head with Sole Plate having Heel and Toe Mass

[0054] Referring to FIGS. 12A - 12E, a semi-circular putter head 1200 is shown for explanation only to aid an understanding of the invention and has an upper portion 1204 and a lower portion 1208. The upper portion 1204 is formed from a first material have a first density and the lower portion 1208 is made from a second material having a second density. The first density is less than the second density. The sole plate of the putter head 1200 increases perimeter weighting and MOI. The upper portion 1204 and lower portion 1208 combine to create a high-MOI putter head 1200 (3000 g·cm 2< - 4000 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1200 can have a MOI ranging from 3000 g·cm 2< - 3500 g·cm 2< or 3500 g·cm 2< - 4000 g·cm 2< . The putter head 1200 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1200 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.b. Putter Head with Pocket and Sole Plate

[0055] illustrated in FIGS. 13A - 13E, a putter head 1300 having a pocket and a sole plate is shown for explanation only to aid an understanding of the invention. As described in more detail below, the pocket of putter head 1300 allows weight to be removed from the putter head 1300 and the sole plate allows for increased perimeter weighting. The putter head 1300 comprises an upper portion 1304 and a lower portion 1308. The upper portion 1304 is formed from a first material having a first density and the lower portion 1308 is formed from a second material having a second density. The first density is less than the second density. The upper portion 1304 and the lower portion 1308 combine to create a high-MOI putter head (4000 g·cm 2< - 5500 g·cm 2< ), while maintain a desirable volume and mass. For example, the putter head 1300 can have an MOI ranging from 4000 g·cm 2< - 4500 g·cm 2< , 4500 g·cm 2< - 5000 g·cm 2< , or 5000 g·cm 2< - 5500 g·cm 2< . The putter head 1300 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1300 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.c. Putter Head with Sole Plate and Ball Retrieval Feature

[0056] Referring to FIGS. 14A-14D, a mallet type putter head is shown for explanation only to aid an understanding of the invention. The putter head 1400 comprises an upper portion 1404 and a lower portion 1408. The lower portion 1408 is a sole plate comprising a toe mass 1446, a heel mass 1448, and a rear mass 1450. The putter head 1400 further comprises a ball retrieval feature 1422. The ball retrieval feature 1422 is configured to pick up and retain a golf ball. The ball retrieval feature and sole plate increase the perimeter weighting thereby increasing the MOI and forgiveness of the putter head 1400. The putter head 1400 can have an MOI ranging from 4000 g·cm 2< - 5000 g·cm 2< . For example, the putter head 1400 can have an MOI ranging from 400 g·cm 2< - 4500 g·cm 2< or 4500 g·cm 2< - 5000 g·cm 2< . The putter head 1400 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1400 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.d. Putter Head with Ball-Outlining Alignment Aid and Sole Plate

[0057] In one embodiment, the putter-type golf club head comprises a two-part construction and includes an alignment aid having a ball-outlining feature. The two-part construction allows the putter-type club head to be formed from multiple materials. Referring to FIGS. 15A and 15B, the putter-type golf club head 1500 comprises an upper portion 1504 and a lower portion 1508. The upper portion 1504 is affixed to the lower portion 1508. The upper portion 1504 is formed from a first material having a first density, and the lower portion 1508 is formed from a second material having a second density. In some embodiments, the first density is less than the second density. As discussed in more detail below, the upper portion 1504 and the lower portion 1508 combine to create a high-MOI putter-type club head 1500 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1500 can have an MOI ranging from 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , 6000 g·cm 2< - 6500 g·cm 2< . The putter head 1500 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1500 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.

[0058] The putter-type club head 1500 further comprises a crown 1536, a sole 1568, a strike face 1520, a rear end 1534, a toe end 1512, and a heel end 1516. The outermost points of the strike face 1520, the rear end 1534, the toe end 1512, and the heel end 1516 define a perimeter 1510 of the putter-type club head 1500. The upper portion 1504 and the lower portion 1508 are affixed together and each form a portion of the crown 1536, a portion of the sole 1568, a portion of the toe end 1512, a portion of the heel end 1516, and a portion of the perimeter 1510. The crown 1536 gradually slopes from the strike face 1520 to the rear end 1534 such that the putter-type club head 1500 is thicker near the strike face 1520 and gradually thins towards the rear end 1534. The slope of the crown 1536 can be linear, curvilinear, parabolic, sinusoidal, or a function of polynomial. Further, the strike face 1520 comprises a strike face center point equidistant from the heel end 1516 and toe end 1512, as well as equidistant from the crown 1536 and the sole 1568.

[0059] In many embodiments, the sole 1568 can be planar. In some embodiments, the sole 1568 can have a slight arch in a heel end 1516 to toe end 1512 direction, wherein the slight arch can be linear, or a function of a polynomial. In some embodiments, the sole 1568 can have a strong arch in the heel end 1516 to toe end 1512 direction, wherein the strong arch can be linear, or a function of a polynomial. The sole 1568 functions to provide a surface to rest the putter-type club head 1500 on the ground plane 1590. As discussed above, the putter-type club head 1500 comprises an upper portion 1504 and a lower portion 1508, where the lower portion 1508 forms a majority of the sole 1568 and rests on the ground plane. The upper portion 1504 sits above the lower portion 1508 when the putter-type club head 1500 is assembled.

[0060] As discussed above, the upper portion 1504 comprises a low-density material (i.e., the first material). In many embodiments, the upper portion 1504 is formed from aluminum. The upper portion 1504 is affixed to the lower portion 1508 to define the crown 1536, the sole 1568, the toe end 1512, the heel end 1516, and the perimeter 1510. The upper portion 1504 comprises an upper portion top surface 1526 and an upper portion bottom surface 1528, where the upper portion top surface 1526 forms a portion of the crown 1536, and the upper portion bottom surface 1528 forms a portion of the sole 1568. The upper portion 1504 further comprises a forward portion 1522 and a rearward extension 1524. The forward portion 1522 comprises the strike face 1520. The rearward extension 1524 extends rearward from the forward portion 1522 towards the rear end 1534. The rearward extension 1524 is generally perpendicular to the strike face 1520 such that the forward portion 1522 and the rearward extension 1524 form a T-shape.

[0061] The forward portion 1522 comprises rear walls opposite the strike face 1520 near the heel end 1516 and the toe end 1512. The rearward extension 1524 comprises side walls near the heel end 1516 and the toe end 1512. The rear wall and side wall near the toe end 1512 define a toe wall 1529, and the rear wall and side wall near the heel end 1516 define a heel wall 1530. The toe wall 1529 and the heel wall 1530 that frame the T-shape of the upper portion 1504. Further, the toe and heel walls 1529, 1530 define cutout regions that allow the upper portion 1504 to receive the lower portion 1508. The cutout regions extend inward from the toe end 1512 or the heel end 1516 toward the center of the upper portion 1504. The cutout regions are bounded by the crown 1536, the perimeter 1510, and either the toe wall 1529, or the heel wall 1530. The toe and heel walls 1529, 1530 define a boundary between the cutout regions and the forward portion 1522, as well as a boundary between the cutout regions and the rearward extension 1524. The cutout portions remove mass from the low-density upper portion 1504, which is replaced with the high-density lower portion 1508 to increase the perimeter weighing of the putter-type club head 1500.

[0062] To further reduce the mass of the upper portion 1504, the upper portion 1504 defines a central recess 1570 that extends from the forward portion 1522 to the rear end 1536. The central recess 1570 removes mass from a central portion of the upper portion 1504, thereby allowing mass to be moved toward the perimeter 1510. The central recess 1570 is defined by a recess wall 1572 and a recess floor 1574. The recess floor 1574 is recessed into the upper portion 1504 away from the upper portion top surface 1526, and the recess wall 1572 circumscribes the recess floor 1574. The recess wall 1572 defines a transition between the upper portion top surface 1526 and the recess floor 1574.

[0063] The recess wall 1572 comprises a height. In some embodiments, the recess wall height slopes with the slope of the crown 1536 such that the recess wall height is larger near the strike face 1520 and smaller near the rear end 1534. In such an embodiment, the recess wall 1572 comprises a height near the rear end 1534 such that the recess floor 1574 is not flush with the upper portion top surface 1526. In other embodiments, the recess wall height remains constant throughout the central recess 1570. The recess floor 1574 is parallel to the ground plane to provide a parallel surface to the ground plane for portions of the alignment aid 1544. The central recess 1570 is located near a middle of the putter-type club head 1500 within the forward portion 1522 and the rear extension 1524 to provide a centered feature for the alignment aid 1544. The central recess 1570 further contributes to the alignment aid 1544, as discussed in more detail below.

[0064] Referring to FIG. 15D-15F, the upper portion 1504 further comprises an alignment aid 1544. The alignment aid 1544 extends along the upper portion 1504 from the forward portion 1522 to the rear end 1534. The alignment aid 1544 comprises several features that work, in conjunction with the central recess 1570, to provide the viewer a visual alignment field that extends from the strike face 1520 to the rear end 1534. The goal is to align the entire putter-type club head 1500 with the golf ball using the alignment aid 1544.

[0065] The alignment aid 1544 comprises several corresponding features that are carefully positioned relative to the central recess 1570. Referring to FIGS. 15D-15F, the alignment aid 1544 comprises a ball-outlining feature 1580, a central line 1576, and a plurality of grooves 1578. The ball-outlining feature 1580 is formed integrally with the upper portion 1504. The ball-outlining feature 1580 is centered on the strike face center point and positioned at an offset from the strike face 1520. The ball-outlining feature 1580 is approximately the width of a golf ball [4.27cm (1.68 inches)] to help frame the golf ball during a swing. In some embodiments, the ball-outlining feature 1580 is slightly wider than the width of a golf ball to allow forgiveness when framing the ball. The ball-outlining feature 1580 is generally golf ball shaped near the strike face 1520.

[0066] The ball-outlining feature 1580 is located on the upper portion top surface 1526 above the central recess 1570. However, the ball-outlining feature 1580 generally follows a perimeter of the central recess 1570. The ball-outlining feature 1580 comprises one or more arcuate portions 1582 and a set of parallel lines 1584 connected to the one or more arcuate portions 1582. At least one arcuate portion 1582 arcs near the strike face 1520 and is offset from the strike face 1520. Referring to FIG. 15D, in some embodiments, the ball-outlining feature 1580 comprises two arcuate portions 1582, where one arcuate portion arcs near the strike face 1520, and the other arcs near the rear end 1534. The one or more arcuate portions 1582 generally resemble one half of a golf ball. The parallel lines 1584 extend rearward from the arcuate portion 1582 toward the rear end 1534. The parallel lines 1584 are generally parallel to the rear extension 1524. The parallel lines 1584 are approximately the width of a golf ball [4.27cm (1.68 inches)]. The ball-outlining feature 1580 is generally the width of a golf ball and generally resembles an elongated golf ball to help the viewer visualize the trajectory of the golf ball. The ball-outlining feature is located on the upper portion top surface 1526 and outlines the central recess 1570.

[0067] The ball-outlining feature 1580 partially or fully circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 connect multiple arcuate portions 1582 to form a circular or oblong ball-outlining feature 1580 that fully circumscribes the central recess 1570, as shown in FIG. 15D. In other embodiments having only one arcuate portion 1582, the parallel lines 1584 extend rearward, thereby defining a U-shaped ball-outlining feature 1580 that partially circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 extend fully to the rear end 1534, as shown in FIG. 15E. In other embodiments, the parallel lines 1584 extend partially to the rear end 1534, as shown in FIG. 15F. The ball-outlining feature 1580 generally follows the perimeter of the central recess 1570 and is located on the upper portion top surface 1526.

[0068] In some embodiments, the ball-outlining feature 1580 is recessed into the upper portion 1504 away from the upper portion top surface 1526, thereby defining a channel. However, in other embodiments, the ball-outlining feature 1580 is flush with the upper portion top surface 1526. Further, in other embodiments, the ball-outlining feature 1580 protrudes from the upper portion top surface 1526. The ball-outlining feature 1580 is positioned on the upper portion top surface 1526 outside of the central recess 1570. The alignment aid 1544 further comprises a central line 1576 and a plurality of grooves 1578 located within the central recess 1570. These features can work in conjunction with the ball-outlining feature 1580 to provide the viewer an elongated alignment aid 1544 that extends from the strike face 1520 to the rear end 1534.

[0069] The central line 1576 is located within the central recess 1570 on the recess floor 1574. The central line 1576 is positioned behind the strike face center point and extends through the entire length of the central recess 1570. The central line 1576 extends perpendicularly from the strike face 1520 towards the rear end 1534. The central line 1576 also extends parallel to the parallel lines 1584 of the ball-outlining feature 1580. In some embodiments, the central line 1576 is further recessed into the recess floor 1574. In other embodiments, the central line 1576 is flush with the recess floor 1574. In some further embodiments, the central line 1576 protrudes from the recess floor 1574. The central line 1576 assists the viewer in finding a center of the alignment aid 1544. The central line 1576 is positioned in a middle of the recess floor 1574.

[0070] The alignment aid further comprises a plurality of grooves 1578 that are positioned on the recess floor 1574 on either side of the central line 1576. The plurality of grooves 1578 are further recessed into the recess floor 1574. In some embodiments, the plurality of grooves 1578 are equally spaced apart from each other. In other embodiments, the plurality of grooves 1578 are concentrated near the central line 1576, or near the toe end 1512 and the heel end 1516. The plurality of grooves 1578 are and are parallel to the central line 1576 and the parallel lines 1584 of the ball-outlining feature 1580. The plurality of grooves 1578 provide a series of alignment lines perpendicular to the strike face 1520 that further assist the viewer in correctly aligning the golf ball.

[0071] As discussed above, each feature of the alignment aid 1544 assists the viewer in aligning the putter-type club head 1500 with the golf ball. The ball-outlining feature 1580 is approximately the width of a golf ball and generally resembles an oblong golf ball. The ball-outlining feature 1580 allows the user to outline the edges of the golf ball with the parallel lines to frame the ball. The central line 1576 is located in a middle of the ball-outlining feature 1580 and behind the strike face center point to help the viewer align the center of the golf ball with the center of the putter-type club head 1500. The plurality of grooves 1578 are parallel to the parallel lines 1584 and the central line 1576 and further assist the user in squaring the golf ball with the putter-type club head 1500.

[0072] The alignment aid 1544 further utilizes the central recess 1570. The central recess 1570 provides a structure for the ball-outlining feature 1580 to outline. Further, the central recess 1570 houses the central line 1576 and the plurality of grooves 1578. The ball-outlining feature 1580 is located near the upper portion top surface 1526, and the central line 1576 and the plurality of grooves 1578 are located on the recess floor 1574 at a vertical offset from the ball-outlining feature 1580. In a top-down view of the putter-type club head 1500, the central line 1576 appears slightly offset from the ball-outlining feature. The offset is contributed to the positioning of the ball-outlining feature 1580 on the upper portion top surface 1526 and the central line 1576 on the recess floor 1574. Further, in a top down view, the recess wall 1572 disappears when the putter-type club head 1500 is in alignment, as shown in FIG. 15D. The different portions of the alignment aid 1544 work in conjunction with the central recess 1570 to help the user align the golf ball. The alignment aid 1544 can comprise a plurality of colors to help the viewer identify the different features of the alignment aid 1544.

[0073] Each portion of the alignment aid 1544 comprises a color. The ball-outlining feature 1580 comprises a first color, and the central line 1576 comprises a second color. Further, the upper portion 1504 comprises a third color. The colors can white, black, grey, silver, red, blue, yellow, green, orange, purple, or any other suitable color. In some embodiments, the first, second, and third colors are similar. In other embodiments, the first, second, and third colors are different from one another. The different colors provide a visual contrast between the different features of the alignment aid 1544, which helps the viewer identify the various features.

[0074] In some embodiments, the contrast is defined by colors that are opposite from one another. For example, the first, second, or third colors can be primary colors selected from the group consisting of red, yellow, and blue, while the other of the first, second, or third colors can be secondary colors selected from the group consisting of green, orange, and purple. Alternatively, the first, second, or third colors can be white or black, while the other of the first, second, or third colors can be the other of white or black. The different or contrasting colors of each feature further assist the viewer in alignment by improving the viewer's ability of the brain to detect a malalignment among parallel lines, a phenomenon known as Vernier Acuity.

[0075] The arrangement of the parallel lines 1584 of the ball-outlining feature 1580 and the central line 1576 take advantage the viewer's Vernier Acuity. In some embodiments, the positioning and the contrasting colors of the parallel lines 1584 of the ball-outlining feature 1580 and the central line 1576 keep the viewer's eyes still and allow the viewer's eyes to naturally stay focused on the central line 1576 to better align the golf ball with the target. In some embodiments, the ball-outlining feature 1580 and the central line 1576 are paint-filled. The shading and sizing of the features are selected to provide an alignment aid 1544 that generally resembles a golf ball.

[0076] The ball-outlining feature 1580 defines width measured between the furthest extent of the parallel lines 1584. The width can be slightly larger than the width of a golf ball to allow forgiveness when framing the golf ball. The width is between 4.19cm to 4.57cm (1.65 inches to 1.80 inches). In some embodiments, the width is approximately 4.19cm, 4.22cm, 4.24cm, 4.27cm, 4.29cm, 4.32cm, 4.34cm, 4.37cm, 4.39cm 4.42cm, 4.45cm, 4.47cm, 4.5cm, 4.52cm, 4.66cm, or 4.572cm (1.65 inches, 1.66 inches, 1.67 inches, 1.68 inches, 1.69 inches, 1.70 inches, 1.71 inches, 1.72 inches, 1.73 inches, 1.74 inches, 1.75 inches, 1.76 inches, 1.77 inches, 1.78 inches, 1.79 inches, or 1.80 inches). In one embodiment, the width is approximately 4.5212xm (1.78 inches).

[0077] The ball-outlining feature 1580 further defines a thickness. The thickness can be large enough to provide a substantial ball-outlining feature 1580. The thickness is between 0.762mm and 3.81mm (0.03 inch and 0.15 inch). In some embodiments, the thickness is approximately 0.762mm, 1.016mm, 1.27mm, 1.524mm, 1.778mm, 2.032mm, 2.286mm, 2.54mm, 2.794mm, 3.048mm, 3.302mm, 3.556mm, or 3.81 mm (0.03 inch, 0.04 inch, 0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, or 0.15 inch).

[0078] The ball-outlining feature 1580 further defines a length. The length is measured in a front to rear direction between the end points of the ball-outlining feature 1580. The length is between 7.366cm to 7.874cm (2.9 inches to 3.1 inches). In some embodiments, the length is approximately 7.366 cm, 7.3914 cm, 7.4168 cm, 7.4422 cm, 7.4676 cm, 7.493 cm, 7.5184 cm, 7.5438 cm, 7.5692 cm, 7.5946 cm, 7.62 cm, 7.6454 cm, 7.6708 cm, 7.6962 cm, 7.7216 cm, 7.747 cm, 7.7724 cm, 7.7978 cm, 7.8232 cm, 7.8486 cm, or 7.874 cm (2.90 inches, 2.91 inches, 2.92 inches, 2.93 inches, 2.94 inches, 2.95 inches, 2.96 inches, 2.97 inches, 2.98 inches, 2.99 inches, 3.00 inches, 3.01 inches, 3.02 inches, 3.03 inches, 3.04 inches, 3.05 inches, 3.06 inches, 3.07 inches, 3.08 inches, 3.09 inches, or 3.10 inches). In one embodiment, the length is 7.8232cm (3.08 inches).

[0079] The alignment aid 1544 is designed to provide a golf ball-like feature that is approximately the width of a golf ball. As discussed above, the alignment aid 1544 comprises different features positioned near or within the central recess 1570. Each feature provides a function to the alignment aid 1544, thereby allowing the user to better align the golf ball with the desired spot on the putter-type golf club head to achieve more accurate shots. Further, the alignment aid 1544 utilizes the central recess 1570 to further assist the viewer in alignment. The alignment aid 1544 and the central recess 1570 are located near a middle of the putter-type club head 1500 within the forward portion 1522 and the rear extension 1524. The rear extension 1524 is configured to allow the upper portion 1504 to receive the lower portion 1508.

[0080] The lower portion 1508 comprises a high-density material (i.e., the second material) than the upper portion 1504. In many embodiments, the lower portion 1508 is formed from stainless steel. Referring to FIG. 15B, the lower portion 1508 comprises a central portion 1538, a toe mass 1545, and a heel mass 1547. The central portion 1538 is a thinned region relative to the toe and heel masses 1545, 1547 and allows the upper portion 1504 to be received by the lower portion 1508. The thinned central portion 1538 also removes mass from a center of the lower portion 1508 that can be reallocated to the toe and heel masses 1545, 1547 to improve the moment of inertia of the putter-type club head 1500. The central portion 1538 comprises a central portion top surface 1540 proximate the upper portion bottom surface 1528. The central portion top surface 1540 comprises a corresponding geometry to the upper portion bottom surface 1528. In some embodiments, the central portion top surface 1528 comprises one or more recesses, as shown in FIG. 15B. The one or more recesses can further reduce the mass from a center of the lower portion 1508. The mass can be redistributed to the toe and heel masses 1545, 1547, which are configured to distribute mass to the peripheries of the putter-type club head 1500.

[0081] The toe and heel masses 1545, 1547 are raised portions relative to the central portion 1538. The toe and heel masses 1545, 1547 are located near the perimeter 1510 to provide perimeter weighting to increase the moment of inertia of the putter-type club head 1500. Furthermore, the weight of the toe and heel masses 1545, 1547 can be tailored to achieve a desired swing weight or overall putter head mass. The toe and heel masses 1545, 1547 comprise a mass top surface 1541 that forms a portion of the crown 1536. The upper portion 1504 and the lower portion 1508 each form a portion of the crown 1536 and the sole 1568. The lower portion 1508 further comprises a lower portion bottom surface 1542 that forms a portion of the sole. The toe and heel masses 1545, 1547 further comprise an inner surface 1561 located near the toe and heel walls 1529, 1530, and an outer surface 1543 that forms a portion of the perimeter 1510. In some embodiments, the outer surface 1543 forms a portion of the toe end 1512, the heel end 1516, or the rear end 1534. The inner surface 1561 defines a transition between the toe mass 1545 and the central portion 1538, as well as a transition between the heel mass 1547 and the central portion 1538. The inner surface 1561 comprises a corresponding geometry to the toe and heel walls 1529, 1530. The lower portion 1508 is configured to receive the upper portion 1504 such that the rearward extension 1524 is situated above the central portion 1538 and between the toe and heel masses 1545, 1547.

[0082] In some embodiments, the toe and heel masses 1545, 1547 form a tight fit with the upper portion 1504. In other embodiments, the inner surface 1561 and toe and heel walls 1529, 1530 define a gap 1595, 1597 therebetween. The gap 1595, 1597 allows toe and heel masses 1545, 1547 of varying sizes to be held within the cutout regions to tailor the weighting of the putter-type club head 1500. The gap 1595, 1597 defines a width measured between the respective inner surface 1561 and toe and heel walls 1529, 1530. The gap width can remain constant throughout the entire gap 1595, 1597, or the gap width can vary throughout the gap 1595, 1597. The gap width can be between 1.27mm to 5.334mm (0.05 inch to 0.21 inch). In some embodiments, the gap width is between 1.27mm to 2.286mm (0.05 inch to 0.09 inch), 1.778mm to 3.302mm (0.07 inch to 0.13 inch), 2.54mm to 4.572mm (0.10 inch to 0.18 inch), and 3.81mm to 5.334cm (0.15 inch to 0.21 inch). In some embodiments, the gap width is 1.27 mm, 1.524 mm,1.778 mm, 2.032 mm, 2.286 mm, 2.54 mm, 2.794 mm, 3.048 mm, 3.302 mm, 3.556 mm, 3.81 mm, 4.064 mm, 4.318 mm, 4.572 mm, 4.826 mm, 5.08 mm, or 5.334 mm (0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, 0.15 inch, 0.16 inch, 0.17 inch, 0.18 inch, 0.19 inch, 0.20 inch, or 0.21 inch). In one embodiment, the gap width is 4.064mm (0.16 inch). The gap width depends on the size and shaping of the toe and heel masses 1545, 1547 and the corresponding cutout regions.

[0083] The toe and heel masses 1545, 1547 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape. The geometry of the toe and heel masses 1545, 1547 corresponds to the geometry of the respective cutout region of the upper portion 1504.

[0084] The toe and heel masses 1545, 1547 provide an additional means of adding mass to the perimeter 1510 for increasing the MOI of the putter-type club head 1500 over a putter without these mass features. The lower portion 1508 comprises a mass between 200 grams to 215 grams. In some embodiments, the mass is between 200 grams to 210 grams, 205 grams to 210 grams, and 210 grams to 215 grams. The mass can be 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, or 215 grams. In one embodiment, the mass is 205.7 grams.

[0085] The lower portion, and the toe and heel masses 1545, 1547 specifically, provide areas of concentrated mass near the perimeter 1510, such that toe and heel masses 1545, 1547 function to increase the moment of inertia of the putter-type club head 1500. The placement of the toe and heel masses 1545, 1547 on the perimeter 1510 increases the MOI since each mass is farther from a center of gravity of the putter-type club head 1500. The upper portion 1504 is affixed to the lower portion 1508, which is formed using the second material, wherein the second material is denser than the first material. The upper portion 1504 can be affixed to the lower portion 1508 with the use of an adhesive.

[0086] The lower portion 1508, in many embodiments, comprise less than 35% of a total volume of the putter-type club head 1500. In some embodiments, the lower portion 1508 comprises less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, or less than 23% of the total volume. In one embodiment, the lower portion 1508 comprises 30.1% of the total volume.

[0087] Although the lower portion 1508 comprises less than half of the volume of the putter-type club head 1500, the lower portion 1508 comprises at least 50% of a total mass of the putter-type club head 1500. In some embodiments, the lower portion 1508 comprises at least 51%, at least 52%, at least 53%, at least 54%, at least 55%, at least 56%, at least 57%, at least 58%, at least 59%, or at least 60% of the total mass. In one embodiment, the lower portion 1508 comprises 56.1% of the total mass. As discussed in more detail below, the lower portion 1508 comprises a low proportion (less than 50%) of the volume of the putter-type club head 1500 and a high proportion (greater than 50%) of the mass of the putter-type club head 1500.

[0088] The combination of the low-density upper portion 1504 with the high-density lower portion 1508, creates a high MOI putter-type club head 1500, without creating an extremely heavy putter. The central recess 1570 shifts a majority of the volume and mass of the putter-type club head 1500 to the perimeter 1510. This shift forms a low volume portion that increases MOI in comparison to a putter milled from a single material. A single material putter-type club head fails to allocate high-density material to the periphery, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams). The advantages of putter head 1500 over a putter head formed from a single material construction are described in the examples below.IV. Putter Head with Ball-Outlining Alignment Aid and Separate Weights

[0089] In one embodiment, the putter-type club head can comprise a two-part construction and can include an alignment aid having a ball-outlining feature. The two-part construction allows the putter-type club head to be formed from multiple materials. Referring to FIGS. 16A and 16B, the putter-type club head 1600 comprises a body 1604, a toe weight 1645, and a heel weight 1647. In some embodiments, the body 1604 is formed from a first material having a first density, and the toe and heel weights 1645, 1647 are formed from a second material having a second density. In some embodiments, the first density is less than the second density. As discussed in more detail below, the body 1604 and the toe and heel weights 1645, 1647 combine to create a high-MOI putter-type club head 1600 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1600 can have an MOI ranging from 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , 6000 g·cm 2< - 6500 g·cm 2< . The putter head 1600 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1600 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.

[0090] The putter-type club head 1600 further comprises a crown 1636, a sole 1668, a strike face 1620, a rear end 1634, a toe end 1612, and a heel end 1616. The outermost points of the strike face 1620, the rear end 1634, the toe end 1612, and the heel end 1616 define a perimeter 1610 of the putter-type club head 1600. The body 1604 and the toe and heel weights 1645, 1647 each form a portion of the crown 1636, a portion of the sole 1668, a portion of the toe end 1612, a portion of the heel end 1616, and a portion of the perimeter 1610. The crown 1636 gradually slopes from the strike face 1620 to the rear end 1634 such that the putter-type club head 1600 is thicker near the strike face 1620 and gradually thins towards the rear end 1634. The slope of the crown 1636 can be linear, curvilinear, parabolic, sinusoidal, or a function of polynomial. Further, the strike face 1620 comprises a strike face center point equidistant from the heel end 1616 and toe end 1612, as well as equidistant from the crown 1636 and the sole 1668.

[0091] In many embodiments, the sole 1668 can be planar. In some embodiments, the sole 1668 can have a slight arch in a heel 1616 to toe 1612 direction, wherein the slight arch can be linear, or a function of a polynomial. In some embodiments, the sole 1668 can have a strong arch in the heel 1616 to toe 1612 direction, wherein the strong arch can be linear, or a function of a polynomial. The sole 1568 functions to provide a surface to rest the putter-type club head 1600 on the ground plane. As discussed above, the putter-type club head 1600 comprises a body 1604, a toe weight 1645, and a heel weight 1647, where the body 1604 forms a majority of the sole 1668 and rests on the ground plane. The toe weight 1645 and heel weight 1647 sit above the body 1604 when the putter-type club head 1600 is assembled.

[0092] As discussed above, the body 1604 comprises a low-density material (i.e., the first material). In many embodiments, the body 1604 is formed from aluminum. The toe weight 1645 and the heel weight 1647 are affixed to the body 1604 to define the crown 1636, the sole 1668, the toe end 1612, the heel end 1616, and the perimeter 1610. The body 1604 comprises an upper surface 1626 and a lower surface 1628, where the upper surface 1626 forms a portion of the crown 1636, and the lower surface 1628 forms a portion of the sole 1668. The body 1604 further comprises a forward portion 1622 and a rear portion 1623, where the forward portion 1622 comprises the strike face 1620. The rear portion 1623 comprises a rearward extension 1624 that extends rearward from the forward portion 1622 towards the rear end 1634. The rearward extension 1624 is generally perpendicular to the strike face 1620. The forward portion 1622 and the rearward extension 1624 form a T-shape.

[0093] The body 1604 defines a central recess 1670 that extends from the forward portion 1622 to the rear end 1634. The central recess 1670 removes mass from a central portion of the body 1604, thereby allowing mass to be moved toward the perimeter 1610. The central recess 1670 is defined by a recess wall 1672 and a recess floor 1674. The recess floor 1674 is recessed into the body 1604 away from the body upper surface 1626, and the recess wall 1672 circumscribes the recess floor 1674.

[0094] The recess wall 1672 comprises a height. In some embodiments, the recess wall height slopes with the slope of the crown 1636 such that the recess wall height is larger near the strike face 1620 and smaller near the rear end 1634. In such an embodiment, the recess wall 1672 comprises a height near the rear end 1634 such that the recess floor 1674 is not flush with the body upper surface 1626. In other embodiments, the recess wall height remains constant throughout the central recess 1670. The recess floor 1674 is parallel to the ground plane to provide a parallel surface to the ground plane for portions of the alignment aid 1644. The central recess 6570 is located near a middle of the putter-type club head 1600 within the forward portion 1622 and the rear extension 1624 to provide a centered feature for the alignment aid 1644. The central recess 1670 further contributes to the alignment aid 1644, as discussed in more detail below.

[0095] The body 1604 further comprises an alignment aid 1644. The alignment aid 1644 is similar to the alignment aid 1544 and is described using similar reference numbers to the alignment aid 1544. For example, the alignment aid comprises one or more arcuate portions 1682 and a set of parallel lines 1684, which are similar to the one or more arcuate portions 1582 and the set of parallel lines 1584 of the alignment aid 1544. However, the alignment aid 1544 is located on the body upper surface 1626, instead of the upper portion top surface 1526, like the alignment aid 1544.

[0096] The alignment aid 1644 comprises a ball-outlining feature 1680, a central line 1676, and a plurality of grooves 1678. The ball-outlining feature 1680 can be similar to the ball-outlining feature 1580 shown in FIGS. 15D-15E. For example, the ball-outlining feature 1680 can partially or fully circumscribe the central recess 1670. In some embodiments, the parallel lines 1684 connect multiple arcuate portions 1682 to form a circular or oblong ball-outlining feature 1680 that fully circumscribes the central recess 1670, as shown in FIG. 15D. In other embodiments having only one arcuate portion 1682, the parallel lines 1684 extend rearward, thereby defining a U-shaped ball-outlining feature 1680 that partially circumscribes the central recess 1670. In some embodiments, the parallel lines 1684 extend fully to the rear end 1634, as shown in FIG. 15E. In other embodiments, the parallel lines 1684 extend partially to the rear end 1634, as shown in FIG. 15F. The ball-outlining feature 1680 generally follows the perimeter of the central recess 1670 and is located on the body upper surface 1626.

[0097] Further, the central line 1676 and the plurality of grooves 1678 can be similar to the central line 1576 and the plurality of grooves 1578 of the alignment aid 1544. The central line 1676 and the plurality of grooves 1678 are located on the recess floor 1674. The central line 1676 is positioned behind the strike face center point and extends through the entire length of the central recess 1670. The plurality of grooves 1678 that are recessed into the recess floor 1674 on either side of the central line 1676. Each feature of the alignment aid 1644 assists the viewer in aligning the putter-type club head 1600 with the golf ball. The alignment aid 1644 also utilizes the central recess 1670. The central recess 1670 provides a structure for the ball-outlining feature 1670 to outline. Further, the central recess 1670 houses the central line 1676 and the plurality of grooves 1678. As discussed above, the alignment aid 1644 is located near the body upper surface 1526 and extends from the forward portion 1622 through the rear extension 1623 to the rear end 1634. The rear portion 1623 is further configured to receive one or more weights.

[0098] The rear portion 1623 further comprises a toe wing 1629 and a heel wing 1630 that receive the toe weight 1645 and the heel weight 1647. The wings 1629, 1630 are located near the perimeter 1610 towards the rear end 1634 such that the rear extension 1624 extends between the wings 1629, 1630. The wings 1629, 1630 are defined between a wing floor 1632 and the sole 1668. The wing floor 1632 is recessed into the body 1604 away from the body upper surface 1626. The wing floor 1632 form a base for the wings 1629, 1630 to receive the weights 1645, 1647.

[0099] The rear portion defines a toe weight recess 1638 and a heel weight recess 1639. The weight recesses 1638, 1369 are located above the wings 1629, 1630 and function to receive the weights 1645, 1647. The weight recesses 1638, 1639 are defined a wing wall 1631 and the wing floor 1632, where the wing wall 1631 is adjacent to a respective recess floor 1632. The toe weight recess 1638 extends inwards from the toe end 1612 toward the center of the body 1604. The heel weight recess 1639 extends from the heel end 1616 toward the center of the body 1604. The weight recesses 1638, 1639 are bounded by the crown 1636, the perimeter 1610, the recess floor 1632, and the wing wall 1631.

[0100] The wing wall 1631 defines a boundary between the wings 1629, 1630 and the forward portion 1622, as well as a boundary between the wings 1629, 1630 and the rearward extension 1624. In some embodiments, the wing walls 1631 can fully encompass the weights 1645, 1647. In other embodiments, the wing walls 1631 can partially encompass the weights 1645, 1647. For example, in some embodiments, the wing wall 1631 can encompass between 30% to 45%, 40% to 65%, 50% to 90%, or 60% to 95% of the weight 1645, 1647.

[0101] The wings recesses 1638, 1369 are configured to receive the weights 1645, 1647 such that the weights 1645, 1647 sit above the wings 1629, 1630. Referring to FIG. 16B, the wings 1629, 1630 comprise an attachment point 1633 that receives a respective weight 1645, 1647. Each attachment point 1633 protrudes from the wing floor 1632 into the respective weight recess 1638, 1639. The attachment point 1633 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0102] The weight recesses 1638, 1369 and the wings 1629, 1630 can comprise any desired geometry. However, in many embodiments, the weight recesses 1638, 1369 and the wings 1629, 1630 comprise a geometry similar or identical to that of the weight 1645, 1647. Each weight recess 1638, 1369 corresponds to a respective wing 1629, 1630 and attachment point 1633 for a respective weight 1645, 1647.

[0103] Referring to FIG. 16A, the putter-type club head 1600 comprises a heel weight 1647 and a toe weight 1645 that correspond to a respective wing 1629, 1630, weight recess 1638, 1639, and attachment point 1633. However, the putter-type club head 1600 is not limited to a heel weight 1647 and a toe weight 1645. In some embodiments, the putter-type club head 1600 can comprise one, two, three, four, five, six, seven, or eight weights. In these embodiments, the putter-type club head 1600 can comprise one, two, three, four, five, six, seven, or eight corresponding wings and attachment points.

[0104] The weights 1645, 1647 comprise a high-density material (i.e., the second material) than the body 1604. In many embodiments, the weights 1645, 1647 are formed from stainless steel. The weights 1645, 1647 are located near the perimeter 1610 and are affixed to the body 1604. Referring to FIGS. 16B and 16D, the weights 1645, 1647 comprise an inner surface 1661 located near the wing wall 1631, and an outer surface 1643 that forms a portion of the perimeter 1610. In some embodiments, the outer surface 1643 forms a portion of the toe end 1612, the heel end 1616, or the rear end 1634. The inner surface 1661 comprises a corresponding geometry to the wing wall 1631.

[0105] In some embodiments, the weights 1645, 1647 form a tight fit with the body 1604. In other embodiments, the inner surface 1661 and the wing wall 1631 define a gap 1695, 1697 therebetween. The gap 1695, 1697 allows weights 1629, 1630 of varying sizes to be held within the weight recesses 1638, 1639 to tailor the weighting of the putter-type club head 1600. The gap 1695, 1697 defines a width measured between the respective inner surface 1661 and wing wall 1631. The gap width can remain constant throughout the entire gap 1695,1697, or the gap width can vary throughout the gap 1695, 1697. The gap width can be between 1.27mm to 5.334mm (0.05 inch to 0.21 inch). In some embodiments, the gap width is between 1.27mm to 2.286mm (0.05 inch to 0.09 inch), 1.778mm to 3.302mm (0.07 inch to 0.13 inch), 2.54mm to 4.572mm (0.10 inch to 0.18 inch), and 3.81mm to 5.334mm (0.15 inch to 0.21 inch). In some embodiments, the gap width is 1.27 mm, 1.524 mm,1.778 mm, 2.032 mm, 2.286 mm, 2.54 mm, 2.794 mm, 3.048 mm, 3.302 mm, 3.556 mm, 3.81 mm, 4.064 mm, 4.318 mm, 4.572 mm, 4.826 mm, 5.08 mm, or 5.334 mm (0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, 0.15 inch, 0.16 inch, 0.17 inch, 0.18 inch, 0.19 inch, 0.20 inch, or 0.21 inch). In one embodiment, the gap width is 4.064mm (0.16 inch).

[0106] The weights 1645, 1647 further comprise a weight upper surface 1640 and a weight lower surface 1642. The weight upper surfaces 1640 form a portion of the crown 1636, and the weight lower surfaces 1642 form a portion of the sole 1668. The weight lower surfaces 1642 are proximate the wing floors 1632 and comprise a corresponding geometry to the respective wings 1629, 1630 and attachment points 1633. Referring to FIG. 16D, the weight lower surface 1642 comprises a stepped-down geometry that corresponds to the respective wing 1629, 1630 and attachment point 1633 geometry. The weights 1645, 1647 slide over the attachment point 1633 and are further secured with an epoxy material. In some embodiments, the wing floors 1632 comprise a plurality of grooves that increase the surface area of the wing floor 1632. The plurality of grooves increase the surface area available for bonding, thereby strengthening the bond between the weights 1645, 1647 and the floor 1632. The geometry of the weight lower surface 1642 facilitates a tight connection between the weights 1645, 1647 and the wings 1629, 1630.

[0107] The weights 1645, 1647 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape. The geometry of the weights 1645, 1647 corresponds to the geometry of the respective weight recess 1638,1639.

[0108] The weights 1645, 1647 provide an additional means of adding mass to the perimeter 1610 for increasing the MOI of the putter-type club head 1600 over a putter without these mass features. Furthermore, the weights 1645, 1647 can be tailored to achieve a desired swing weight or overall putter head mass. The weights 1645, 1647 comprise a combined mass between 45 grams to 70 grams. In some embodiments, the mass is between 45 grams to 60 grams, 55 grams to 70 grams, and 55 grams to 65 grams. The combined mass can be 45 grams, 46 grams, 47 grams, 48 grams, 49 grams, 50 grams, 51 grams, 52 grams, 53 grams, 54 grams, 55 grams, 56 grams, 57 grams, 58 grams, 59 grams, 60 grams, 61 grams, 62 grams, 63 grams, 64 grams, 65 grams, 66 grams, 67 grams, 68 grams, 69 grams, or 70 grams. The weights 1645, 1647 provide areas of concentrated mass near the perimeter 1610, such that each weight 1645, 1647 functions to increase the moment of inertia of the putter-type club head 1600. The placement of each weight 1645, 1647 on the perimeter 1610 increases the MOI since each mass is farther from a center of gravity of the putter-type club head 1600. Each weight 1645, 1647 is affixed to the body 1604 using the second material, wherein the second material is denser than the first material.

[0109] The weights 1645, 1647, in many embodiments, comprise less than 25% of a total volume of the putter-type club head 1600. In some embodiments, the weights 1645, 1647 comprise less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, or less than 13% of the total volume.

[0110] Although the weights 1645, 1647 comprise less than half of the volume of the putter-type club head 1600, the weights 1645, 1647 comprise at least 30% of a total mass of the putter-type club head 1600. In some embodiments, the weights 1645, 1647 comprise at least 31%, at least 32%, at least 33%, at least 34%, at least 35%, at least 36%, at least 37%, at least 38%, at least 39%, or at least 40% of the total mass.

[0111] The combination of the low-density body 1604 with the high-density weights 1645, 1647, creates a high MOI putter-type club head 1600, without creating an extremely heavy putter. The central recess 1670 shifts a majority of the volume and mass of the putter-type club head 1600 to the extremities of the body 1604. This shift forms a low volume portion that increases MOI in comparison to a putter milled from a single material. A single material putter-type club head fails to allocate high-density material to the periphery, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams).V. Three-Part Putter Head

[0112] In Figure 18 which is shown for explanation only to aid an understanding of the invention and, rather than a two part putter, the putter type golf club head can comprise a three part construction including a crown portion 1802 in addition to the upper portion and the lower portion. Providing a three-part putter head comprising a crown portion 1802 in addition to the upper portion and the lower portion allows the mass distribution throughout the putter head to be more precisely controlled and optimized to increase the MOI of the putter head.

[0113] The upper portion of the three-part putter-type golf club head can be similar to one or more of the upper portions described in reference to previous embodiments and can be made of the first material described above. Similarly, the lower portion of the three-part putter-type golf club head can be similar to one or more of the lower portions described in reference to previous embodiments and can be made of the second material described above.

[0114] The three-part putter head further comprises a crown portion made of a third material different than both the first material of the upper portion and the second material of the lower portion. The third material can be lightweight and can comprise a density less than both the first density and the second density. In many embodiments, the crown portion 1802 can be joined to the top of the upper portion and can form the uppermost surface of the putter head.

[0115] In many embodiments, the crown portion of the putter head having the third material comprises a third density ranging between 0.5 g / cc and 3.5 g / cc. The third density can range between 1.5 g / cc to 2.5 g / cc. In some embodiments, the third density can range between 0.5 - 0.75 g / cc, 0.75 - 1.0 g / cc, 1.0 - 1.25 g / cc, 1.25 - 1.5 g / cc, 1.5 - 1.75 g / cc, 1.75 - 2.0 g / cc, 2.0 - 2.25 g / cc, 2.25 - 2.5 g / cc, 2.5 - 2.75 g / cc, 2.75 - 3.0 g / cc, or 3.25 - 3.5 g / cc. In one embodiment, the third density of the crown portion 1802 can range between 1.0 - 2.0 g / cc. In some embodiments, the third density can be less 3.5 g / cc, less than 3.0 g / cc, less than 2.5 g / cc, less than 2.0 g / cc, less than 1.5 g / cc, or less than 1.0 g / cc. In some embodiments, the third density can be 0.5 g / cc, 0.75 g / cc, 1.0 g / cc, 1.25 g / cc, 1.50 g / cc, 1.75 g / cc, 2.0 g / cc, 2.25 g / cc, 2.50 g / cc, 2.75 g / cc, 3.0 g / cc, 3.25 g / cc, or 3.50 g / c.

[0116] The crown portion of the putter head having the third material can be made from any one or combination of the following: aluminum, aluminum alloy, ADC-12, a polymeric material, a composite material, a filled thermoplastic, a fiber-reinforced composite, or any other suitable low-density material.

[0117] Inclusion of the low-density crown portion allows for an increase in the MOI of the putter head. Replacing portions of the club head that would otherwise be made of either the first material or the second material creates discretionary mass that can be reallocated throughout the putter head.a. Three-Part Spade Shaped Embodiment

[0118] FIGS. 18A-18D illustrate for explanation only and to aid an understanding of the invention, a first embodiment of the three-part putter-type golf club head 1800. Putter head 1800 is a spade shaped putter head 1800, similar to the two-part spade shaped putter head 700 of FIGS. 7A-7C. The three-part spade shaped putter head 1800 comprises an upper portion 1804, a lower portion 1808, and a crown portion 1802, and a hollow interior cavity 1850 formed between the upper portion 1804, lower portion 1808, and crown portion 1802. The upper portion 1804 is made from a first material having a first density, the lower portion 1808 is made from a second material having a second density, and the crown portion 1802 is made from a third material having a third density. The first density is less than the second density. The third density is less than both the first density and the second density. The upper portion 1804, lower portion 1808, and crown portion 1802 combine to create a high-MOI putter head (3500 g·cm 2< - 5000 g·cm 2< ) 1800 while maintaining a desirable volume and mass. For example, in some embodiments, the putter head 1800 can comprise an MOI approximately between 3500 g·cm 2< and 4000 g·cm 2< , between 4000 g·cm 2< and 4500 g·cm 2< , or between 4500 g·cm 2< and 5000 g·cm 2< . In some embodiments, the putter head 1800 can comprise an MOI approximately between 3500 g·cm 2< and 3750 g·cm 2< , between 3750 g·cm 2< and 4000 g·cm 2< , between 4000 g·cm 2< and 4250 g·cm 2< , between 4250 g·cm 2< and 4500 g·cm 2< , between 4500 g·cm 2< and 4750 g·cm 2< , or between 4750 g·cm 2< and 5000 g·cm 2< .

[0119] As illustrated in FIG. 18A, the upper portion 1804 forms a majority of the main body of the putter head 1800. The upper portion 1804 comprises a base 1830 and a plurality of walls extending vertically from the base 1830. The upper portion 1804 can comprise a plurality of perimeter walls including a front wall 1812 defining a strike face 1820, a toe wall 1814, a heel wall 1816, and a rear wall 1832. The front wall 1812 is adjacent to the toe wall 1814 and the heel wall 1816, and opposite to the rear wall 1832. An exterior surface of the front wall 1812 forms the strike face 1820 while an interior surface of the front wall 1812 forms a back face 1824. The toe wall 1814 is adjacent to the front wall 1812 and the rear wall 1832, and opposite to the heel wall 1816. The heel wall 1816 is also adjacent to the front wall 1812 and the rear wall 1832, but opposite to the toe wall 1814.

[0120] The plurality of perimeter walls can form the majority of a perimeter of the putter head 1800. The base 1830 can extend from the front wall 1812 to the rear wall 1832 and from the toe wall 1814 to the heel wall 1816. The base 1830 further comprises an upper surface 1831 and a lower surface 1833 opposite the upper surface 1831. The lower surface 1833 of the base 1830 forms at least a portion of the sole 1868. In many embodiments, referring to FIG. 18C, the lower surface 1833 can comprise a recessed area 1840 configured to receive the lower portion 1808 such that the lower surface 1833 of the base 1830 forms part of the sole 1868 and a bottom surface 1882 of the lower portion 1808 forms the remainder of the sole 1868.

[0121] The upper portion 1804 further comprises a plurality of internal walls 1838 extending vertically from the base 1830. Each of the plurality of internal walls 1838 are inset with respect to the perimeter of the putter head 1800. The plurality of internal walls 1838 therefore do not form any portion of the club head perimeter. As illustrated in FIG. 18A, the plurality of perimeter walls and the plurality of internal walls 1838 can be interconnected. The interconnection between the plurality of perimeter walls and the plurality of internal walls 1838 can collectively form a cavity profile, when viewed from above, wherein the cavity profile defines the shape of the hollow interior cavity 1850. The shape of the cavity profile is defined by the orientation and shaping of the plurality of perimeter walls and the plurality of internal walls 1838. In some embodiments, such as the embodiment illustrated in FIG. 18A, the upper portion 1804 can comprise one or more internal walls 1838 extending substantially perpendicular to the strike face 1820 and one or more internal walls 1838 extending substantially parallel to the strike face 1820. In other embodiments, one or more internal walls 1838 can extend at an angle with respect to the strike face 1820. FIG. 18A illustrates the plurality of internal walls 1838 being formed as substantially straight walls, but in other embodiments, the putter head 1800 can comprise one or more internal walls 1838 that are curved. The top of the upper portion 1804 can be open such that the upper portion 1804 by itself does not enclose any hollow portions or interior cavities.

[0122] The upper portion 1804 can further define one or more external portions 1835 situated outside of the cavity profile. The one or more external portions 1835 form areas of the putter head 1800 wherein the upper surface 1831 of the base 1830 is exposed to the exterior of the putter head 1800. The one or more external portions 1835 can be partially bounded by the exterior surface of one or more internal walls 1838, but the external portions 1835 are not bounded on any sides by any of the plurality of perimeter walls.

[0123] The upper portion 1804 further comprises a central aperture 1864 extending through a portion of the base 1830. The central aperture 1864 extends through both the upper surface 1831 and the lower surface 1833 of the base 1830. The central aperture 1864 shifts a large portion of the volume and mass of the putter head 1800 to the extremities of the upper portion 1804. The central aperture 1864 can be configured to be covered by the lower portion 1808 to enclose the hollow interior cavity 1850.

[0124] As illustrated by FIGS. 18A and 18B, the crown portion 1802 forms the majority of the top surface of the putter head 1800. The crown portion 1802 can comprise a thin, cover-like structure configured to overlay the upper portion 1804. The plurality of walls can provide surfaces 1834 to which the crown portion 1802 is attached. As illustrated in FIG. 18A, the shape of the crown portion 1802 is complementary to the geometry of the upper portion 1804. In particular, the shape of the crown corresponds to the cavity profile formed by the plurality of upper portion walls. The perimeter edges of the crown portion 1802 can be configured to attach to the top surfaces 1834 of the upper portion perimeter walls and the upper portion internal walls 1838. As illustrated in FIG. 18B, by overlaying the top of the lower portion 1808, the crown portion 1802 entirely encloses the top of the hollow interior cavity 1850.

[0125] The crown portion 1802 comprises a front edge 1870 extending along the front wall 1812 in a heel-to-toe direction. The front edge 1870 can extend all the way from the toe wall 1814 to the heel wall 1816. The crown portion 1802 further comprises a central extension 1842, a heel extension 1846, and a toe extension 1848. The central extension 1842 extends rearward from the front edge 1870, near the center of the front wall 1812. The central extension 1842 extends all the way from the front wall 1812 to the rear wall 1832 and covers a central area of the cavity profile. The heel extension 1846 extends rearward from a heel side of the front edge 1870. The heel extension 1846 extends along the heel wall 1816 and extends a portion of the way from the front wall 1812 to the rear wall 1832. The toe extension 1848 extends rearward from a toe side of the front edge 1870. The toe extension 1848 extends along the toe wall 1814 and extends a portion of the way from the front wall 1812 to the rear wall 1832.

[0126] Furthermore, the crown portion 1802 of the putter head 1800 can comprise one or more alignment features 1836. The alignment feature 1836 can be any one or combination of the following: a line, a series of lines, milling troughs, a circle, a dashed line, a triangle, a channel, or any other desired alignment feature 1836. In the embodiment of FIGS. 18A-18D, the central extension 1842 is configured to be the width of a golf ball (approximately 4.27 cm). The alignment features 1836, extending along the crown portion 1802, function to provide the viewer a visual alignment field that extends the width of the golf ball, from the strike face 1820 to the rear of the putter head 1800. The goal is to align the entire putter head 1800 with the golf ball using these alignment features 1836 along the crown portion 1802.

[0127] As illustrated by FIG. 18D, the lower portion 1808 can form a majority of the sole 1868. The lower portion 1808 can be formed as a substantially flat, high-density sole plate. In many embodiments, the lower portion 1808 is received within the recessed area 1840 of the upper portion lower surface 1833. The lower portion 1808 can be received within the upper portion 1804 such that a bottom surface 1882 of the lower portion 1808 sits flush with the lower surface 1833 of the upper portion 1804. In this way, the bottom surfaces 1833, 1882 of the upper portion 1804 and lower portion 1808 combine to define a generally continuous sole surface at the bottom of the putter head 1800. In some embodiments, referring to FIG. 18A, the top surface 1880 of the lower portion 1808 can comprise one or more recesses 1886. The one or more recesses 1886 can be located near the center of the lower portion 1808. The one or more recesses 1886 can serve to shift mass toward the perimeter of the lower portion 1808.

[0128] Referring to FIG. 18D, the lower portion 1808 is located toward the rear wall 1832 of the putter head 1800 and can extend substantially between the heel wall 1816 and the toe wall 1814. As such, the majority of the sole 1868 proximate the rear wall 1832 is formed by the lower portion bottom surface 1882. In many embodiments, the lower portion 1808 can be spaced rearwardly from the front wall 1812. As such, the majority of the sole 1868 proximate the strike face 1820 can be formed by the lower surface 1833 of the upper portion 1804.

[0129] The lower portion 1808 is configured to be received such that it covers the upper portion aperture 1864 from the bottom of the putter head 1800. The lower portion 1808 can seal off the hollow interior cavity 1850 from the sole 1868, enclosing the bottom of the hollow interior cavity 1850.

[0130] When joined together, the upper portion 1804, the lower portion 1808, and the crown portion 1802 form a hollow interior cavity 1850 within the putter head 1800. The hollow interior cavity 1850 is bounded between interior surfaces of the perimeter walls and internal walls 1838 of the upper portion 1804, an underneath surface (not shown) of the crown portion 1802, and the top surface 1880 of the lower portion 1808. The hollow interior cavity 1850 removes a large amount of mass from near the center of gravity. The hollow interior cavity 1850 thereby increases the MOI of the putter head 1800 by allowing mass to be shifted toward perimeter of the putter head 1800.

[0131] In FIGS. 18A-18D, the hollow interior cavity 1850 is completely enclosed by the upper portion 1804, lower portion 1808, and crown portion 1802 such that there are no openings from the exterior of the putter head 1800 into the hollow interior cavity 1850. Completely enclosing the interior cavity 1850 by the upper portion 1804, lower portion 1808, and crown portion 1802 provides the putter head 1800 with the high MOI of a hollow putter head while retaining the appearance of a solidly constructed putter head.

[0132] In some examples the hollow interior cavity 1850 can comprise a filler material (not shown). In some embodiments, the filler material can completely fill the volume of the hollow interior cavity 1850. In other embodiments, the filler material can fill only a portion of the volume of the hollow interior cavity 1850. In some embodiments the filler material can fill greater than 5%, greater than 10%, greater than 20%, greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90% of the volume of the hollow interior cavity 1850. In other embodiments, the filler material can fill less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5% of the volume of the hollow interior cavity 1850.

[0133] The filler material can be a polymer. The polymer can comprise a thermoplastic, a thermoplastic elastomer, polyurethane, ethylene, vinyl acetate, ethylene vinyl acetate (EVA), polyolefin copolymer, styrene, styrene-butadiene, a polymer foam material, any other suitable polymer material, or any combination thereof. In other embodiments, the filler material can comprise an elastomer, a polyurethane elastomer, a silicone, a silicone elastomer, a rubber, or a vulcanized natural rubber latex. In other embodiments still, the filler material can be an epoxy, a resin, an adhesive, a polyurethane adhesive, a glue, or any other suitable adhesive. For example, the carrier can be a polyurethane adhesive such as Gorilla Glue (Gorilla Glue Company, Cincinnati Ohio). In another example, the filler material can be a polyurethane elastomer such as Freeman 1040 (Freeman Manufacturing & Supply Company, Avon Ohio), or a polyurethane based thermoplastic elastomer such as Freeman 3040 (Freeman Manufacturing & Supply Company, Avon Ohio). In some embodiments, the filler material can be a lattice material. The lattice filler material can be formed from a metal using processes such as casting, die casting, co die casting, additive manufacturing, or metallic 3D printing.

[0134] The combination of the low density first material upper portion 1804 and low density third material crown portion 1802 with the high density second material lower portion 1808, creates a high MOI putter head 1800, without creating an extremely heavy putter head 1800. Providing the hollow interior cavity 1850 allows for the inclusion of a dense, yet low volume lower portion 1808 that increases the MOI of the putter head 1800, in comparison to a putter head milled from a single material. A single material putter head fails to allocate high density material to the perimeter, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams). In one example, the putter head 1800 comprises a high MOI, a desirable volume (91 cc), and a desirable mass (361 grams).

[0135] The lower portion 1808, in most embodiments, comprises less than 40% of a total volume of the putter head 1800. In some embodiments, the lower portion 1808 comprises less than 39% of the total volume of the putter head 1800, less than 38% of the total volume of the putter head 1800, less than 37% of the total volume of the putter head 1800, less than 36% of the total volume of the putter head 1800, less than 35% of the total volume of the putter head 1800, less than 34% of the total volume of the putter head 1800, less than 33% of the total volume of the putter head 1800, less than 32% of the total volume of the putter head 1800, less than 31% of the total volume of the putter head 1800, or less than 30% of the total volume of the putter head 1800.

[0136] The inclusion of the hollow interior cavity 1850 allows a large proportion of the mass of the putter head 1800 to be concentrated in the lower portion 1808 without creating an extremely heavy putter head 1800. Although the lower portion 1808 comprises less than 40% of the volume of the putter head 1800, the lower portion 1808 comprises at least 60% of an overall mass of the putter head 1800. In some embodiments, the lower portion 1808 comprises at least 61 % of the mass of the putter head 1800, at least 62% of the mass of the putter head 1800, at least 63% of the mass of the putter head 1800, at least 64% of the mass of the putter head 1800, at least 65% of the mass of the putter head 1800, at least 66% of the mass of the putter head 1800, at least 67% of the mass of the putter head 1800, at least 68% of the mass of the putter head 1800, at least 69% of the mass of the putter head 1800, or at least 70% of the mass of the putter head 1800.

[0137] The beneficial shift of mass to the perimeter of the putter head 1800, through the use of a high density, low volume lower portion 1808 and the inclusion of a hollow interior cavity 1850 increases the MOI of the putter head 1800. The putter head 1800 comprises an increased MOI over a putter head with the same volume, mass, and single material construction (i.e., a putter head milled of a single stainless steel block, or a putter head investment cast of a single material).VI. Benefits

[0138] The putter-type golf club head provides MOI, CG, feel, and weighting benefits, in a putter-type golf club head with an upper and lower portion having different densities and / or without using mechanically fastened weights or weight ports. By creating an upper portion and lower portion of a putter-type golf club head from two different material, the weighting of the club head shifts towards the peripheries of the putter-type golf club head, without any weight ports or attachments to the heel end and toe end of the putter-type golf club head. This shift in weight, towards the peripheries of the putter-type golf club head, raises the MOI of the club head about the y-axis (Iyy), therefore preventing the rotation about the y-axis and assuring the strike face is square to a golf ball during impact. The increase in MOI about the y-axis helps achieve a straighter ball path and improve the outcome of off-centered hits (impact at the heel end or toe end).

[0139] By creating the 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 desirable overall weight. In some embodiments, the moment of inertia of the golf club head about the y-axis center of gravity is between 3500 g·cm 2< - 6500 g·in 2< . In other embodiments the moment of inertia of the golf club head about the y-axis center of gravity can be between 3500 g·cm 2< - 4000 g·cm 2< , 4000 g·cm 2< - 4500 g·cm 2< , 4500 g·cm 2< - 5000 g·cm 2< , 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , or 6000 g·cm 2< - 6500 g·cm 2< . The golf club head comprises a 2%-15% increase in MOI about the y-axis over a club head devoid of a multi-material construction (i.e. a single material). In other embodiments, the golf club head has a 2%-5%, 5%-10%, or 10%-15% increase over a club head with a single material.

[0140] The putter-type golf club head with 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 with the same volume, mass, and single material construction (i.e., a putter milled of a single material such as a steel putter or a putter investment cast of a single material). In some embodiments, the putter-type golf club head with upper and lower portions of two different materials, increases the MOI about the y-axis center of gravity by at least 35%, by at least 40%, by at least 45%, by at least 50%, by at least 55%, by at least 60%, by at least 65%, by at least 70%, by at least 75%, by at least 80%, by at least 85%, by at least 90%, by at least 95%, by at least 95%, by at least 100%, or by at least 105%, over a putter with the same volume, mass, and single material construction.

[0141] The putter-type golf club head with the alignment aid 1544 of FIGS. 15A-15D provides visual advantages that are pleasing to the eye and created repeatability in putting. The alignment aid 1544 assists the user in properly aligning the putter head with the golf ball on a consistent basis. The alignment aid 1544 comprises a ball outlining feature 1580 which helps the viewer align the putter head with the outsides of the golf ball and a central line 1576 that aligns the center of the golf ball with the putter head. The proper alignment of the putter head with the golf ball enables the user to start the ball on the intended line. The putter head including the alignment aid 1544 provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye to create a consistent putting stroke.VII. EXAMPLES a. Example 1 -High MOI Putter Head

[0142] Example 1 putter head 1300 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The example 1putter head 1300 comprised an upper portion 1304 formed from a low-density material and a lower portion 1308 formed from a high-density material as illustrated in FIGS. 13A - 13E. The lower portion 1308 further comprised a sole plate including a toe mass 1345 and a heel mass 1347 to increase perimeter weighting. The upper portion 1300 further comprised a pocket 1372 to allow for mass removal from a center portion of the putter head 1300. The control putter head comprised a similar mass, volume, and weight to the exemplary putter head 1300, but comprised a single material construction.

[0143] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the Example 1putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the Example 1putter 1300 having a total mass of 363.2 grams and a total volume 85.2 cc. The lower portion 1308 comprised a sole plate mass of 207.4 grams and a sole plate volume of 26.55 cc. The lower portion 1308 comprised 57.1% of the total mass of putter 1300 while comprising 31.16% of the total volume of the putter 1300.

[0144] The Example 1putter 1300 comprised a MOI of 4368 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 3702 g·cm 2< about the y-axis (Iyy). The results show the Example 1putter head 1300 comprised a 10.78% increase in MOI over the control putter head. The Example 1putter head 1300 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The Example 1putter 1300 achieves a high MOI with a multi-material construction over a putter head formed from a single material.b. Example 2 -High MOI Putter Head

[0145] Example 2 putter head 1400 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The Example 2putter 1400 comprised an upper portion 1404 formed from a low-density material and a lower portion 1408 formed from a high-density material as illustrated in FIGS. 14A - 14D. The lower portion 1408 further comprised a sole plate including a toe mass 1446, a heel mass 1448, and a rear mass 1450 to increase perimeter weighting. The Example 2putter head 1400 further comprised a ball retrieval feature 1422 located on the sole 1442. The ball retrieval feature 1422 further increases perimeter weighting by removing material and mass from a central area of the putter head 1400. The control putter head comprised a similar mass, volume, and weight to the Example 2putter head 1300, but comprised a single material construction.

[0146] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the Example 2putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the Example 2 putter 1400 having a total mass of 360 grams and a total volume 80.79 cc. The lower portion 1408 comprised a sole plate mass of 228 grams and a sole plate volume of 29.74 cc. The lower portion 1408 comprised 63% of the total mass of putter 1400 while comprising 37% of the total volume of the putter 1400.

[0147] The Example 2 putter 1400 comprised an MOI of 4710 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 4474 g·cm 2< about the y-axis (Iyy). The test results show the Example 2 putter head 1400 comprised a 5.26% increase in MOI over the control putter head. The Example 2 putter head 1400 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The Example 2 putter 1400 achieves a high MOI with a multi-material construction over a putter head formed from a single material.c. Example 3 - Exemplary High MOI Putter Head

[0148] An exemplary putter head 1500 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The exemplary putter head 1500 comprised an upper portion 1504 formed from a low-density material and a lower portion 1508 formed from a high-density material as illustrated in FIGS. 15A - 15D. The lower portion 1508 comprised a sole plate including a toe mass 1545 and a heel mass 1547 to increase perimeter weighting. The upper portion 1504 further defines a central recess 1570 to allow for mass removal from a center portion of the putter-type club head 1500. The control putter head comprised a similar mass, volume, and weight to the exemplary putter head 1500, but comprised a single material construction.

[0149] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the exemplary putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the exemplary putter-type club head 1500 having a total mass of 366.5 grams and a total volume of 87 cc. The lower portion 1508 comprised a sole plate mass of 205.7 grams and a sole plate volume of 26.2 cc. The lower portion 1508 comprised 56.1% of the total mass of putter-type club head 1500 while comprising 30.1% of the total volume of the putter-type club head 1500.

[0150] The exemplary putter-type club head 1500 comprised a MOI of 4416 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 4324 g·cm 2< about the y-axis (Iyy). The test results show the exemplary putter head comprised a 2.12% increase in MOI over the control putter head. The exemplary putter head 1500 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The exemplary putter head 1500 achieves a high MOI with a multi-material construction over a putter head formed from a single material. The exemplary putter head 1500 further comprised a ball outlining alignment aid to improve putt consistency while being pleasing to the eye during repeated ball impacts.d. Example 4 - Putter Alignment Aid Test

[0151] Further described herein is a player test comparing two putter-type club heads having different alignment aids. The club heads were mallet-style club heads having a similar shape but comprised different alignment aid styles. The results compared the effect of the different alignment aid types on player satisfaction and performance.

[0152] The first putter-type club head (hereafter referred to as the "control club head") comprised an alignment aid (hereafter referred to as the "control aid"), similar to club head 1200, as shown in FIG. 12A. The control aid was positioned on the crown and included three parallel lines that extended from the strike face to the rear end. The central line was positioned behind the strike face center point, and the remaining lines were positioned on the heel and toe sides of the central line. The three parallel lines were approximately the width of a golf ball [i.e. 4.267 cm (1.68 inches)]. The parallel lines comprised a color different from the color of the control club head. The control aid further comprised a plurality of grooves positioned between the parallel lines.

[0153] The second putter-type club head (hereafter referred to as the "exemplary club head") comprised an alignment aid (hereafter referred to as the "exemplary aid"), similar to the alignment aid 1544 associated with club head 1500, as shown in Fig. 15D. The exemplary club head defined a central recess that extended from the strike face to the rear end. The exemplary aid comprised a ball-outlining feature that outlined a perimeter of the central recess. The ball-outlining feature included two arcuate portions, where one arcuate portion arced near the strike face and the other arced near the rear end. The arcuate portions were connected by a set of parallel lines to form a continuous perimeter around the central recess. The ball-outlining feature was approximately the width of a golf ball and resembled an oblong golf ball shape due to the arcuate portions. The ball-outlining feature comprised a color different from the color of the exemplary club head. The exemplary aid further comprised a central line positioned within the central recess and extending along the length of the central recess. The central line was further positioned behind the strike face center point.

[0154] A player test was conducted to compare the alignment aid performance between the exemplary aid and the control aid. The player test involved thirty players who participated in a survey that compared their experiences with the exemplary aid having a ball-outlining feature, and the control aid devoid of a ball-outlining feature. The players tested each club head under similar conditions, where the putter club heads included similar shaft lengths and similar loft angles. Further, the player test was conducted on a typical putting surface. The test involved hitting a golf ball across the putting surface with the control putter head and the exemplary putter head.

[0155] After testing, the participants rated the club head performance and satisfaction based on five parameters. The parameters included the alignment aid look, the alignment aid performance, the overall club head feel, accuracy, and the comfort at address position. Based on these parameters, the club heads were given a rating of between 1 to 5. A rating of 1 represented the lowest level of satisfaction, where the club head only met 1 of the parameters. A rating of 5 represented the highest level of satisfaction, where the club head met all 5 of the parameters. A rating of 4 represented a high level of satisfaction, where the club head met 3 or more of the parameters. Control Exemplary Increase Number of Participants who Rated 4 or 5 (out of 30)132053.8%Percentage of Participants who Rated 4 or 546.4%68.9%48.5%

[0156] Table 1 above illustrates the number of participants who gave each sample club head a "good" rating, where a "good" rating was a score of 4 or 5. The exemplary club head was rated higher than the control club head. The control club head received a "good" rating from 46.4% of the players while the exemplary club head received a "good" rating from 68.9% of the players.

[0157] The test resulted in the exemplary aid meeting more of the parameters than the control aid (e.g., alignment aid look, alignment aid performance, the overall club head feel, accuracy, and comfort at the address position). The participants in the player test felt the exemplary putter head performed better than the control putter head. The exemplary aid provides advantages over the control aid. The exemplary aid included multiple components that each provided a function to the alignment aid. The ball-outlining feature defined an oblong shape that generally resembled a golf ball and helped the viewer outline the sides of the golf ball. The central line helped the viewer find the center of the club head. Further, the exemplary aid utilized the central recess, where the recess walls disappeared when the club head was in alignment. The exemplary putter head comprising the exemplary aid provided improved player performance and satisfaction while comprising a high MOI.

[0158] As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and / or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St. Andrews (R&A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and / or sold as conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.

[0159] The above examples may be described in connection with a putter-type golf club, the apparatus, methods, and articles of manufacture described herein. Alternatively, the apparatus, methods, and articles of manufacture described herein may be applicable other type of sports equipment such as a hockey stick, a tennis racket, a fishing pole, a ski pole, etc.

Examples

embodiment

h. Dual-Rail Embodiment

[0051]Referring to FIGS. 9A and 9B, a dual-rail putter head 900 is shown for explanation only to aid an understanding of the invention and has a upper portion 904 and a lower portion 908. The upper portion 904 is made from a first material have 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 lower portion 908 combine to create a high-MOI putter head 900 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.

i. Circular Embodiment

[0052]Referring to FIG. 10A-10C, a circular putter head 1000 is shown for explanation only to aid an understanding of the invention and has an upper portion 1004 and a lower portion 1008. The lower portion 1008 is made from a first material have 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 de...

TECHNICAL FIELD

[0001] This disclosure relates generally to golf clubs and relates more particularly to a multi-component putter type golf club head.BACKGROUND

[0002] In many putter-type golf club heads, weight distribution is used to vary 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 faceplate inserts, inserts for the back of portion of the face, and attachments for the outer perimeter of the toe and heel regions. In particular putter-type golf club heads, often use weight ports in the heel and toe regions that can be removably attached by a fastener, or permanently attached through a variety of epoxies, glues, or machining methods. The use of weight ports in the heel and toe regions, the increases the MOI in the putter head, thereby producing a straighter ball path after impact.

[0003] Although these weight ports in the heel and toe regions increase MOI, they increase the weight of the golf club head and can make the golf club head heavier than an ideal weight for a putter. In addition, installing weight ports into a golf club putter head requires a cavity or recess to place these weight ports into the putter head during manufacturing, thereby increasing the cost of that putter head. Additionally, the weight ports can cause vibrations within the cavity or recess during impact, when the golf club head contacts a golf ball. These cavities and recesses can cause the sound of the club head to change as well, creating a hollow sound within the club head.

[0004] A putter-type golf club head including an upper portion forming part of the crown and the sole, and comprising a strike face, is known from US 2007 / 0238547 A1. In the known structure, the upper portion comprises a forward portion and a rearward extension, and the lower portion comprises toe and heel mass portions, wherein the lower portion is configured to receive the upper portion such that the rearward extension is positioned above a central portion and between the toe and heel mass portions.

[0005] There is a need in the art to develop a putter having a desirable sound, perimeter weighting, and an ideal weight for balanced putting while being pleasing to the eye of the user to create repeatability for a putt.SUMMARY OF THE INVENTION

[0006] The invention is defined by the appended claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A illustrates an exploded view of a blade putter type golf club head. FIG. 1B illustrates an isometric view of the blade putter type golf club head of FIG. 1A. FIG. 1C illustrates a side view of the blade putter type golf club head of FIG. 1A. FIG. 2A illustrates an exploded view of a blade putter type golf club head. FIG. 2B illustrates an isometric view of the blade putter type golf club head of FIG. 2A. FIG. 2C illustrates a side view of the blade putter type golf club head of FIG. 2A. FIG. 3A illustrates an exploded view of a crescent putter type golf club head. FIG. 3B illustrates an isometric view of the crescent putter type golf club head of FIG. 3A. FIG. 3C illustrates a side view of the crescent putter type golf club head of FIG. 3A. FIG. 4A illustrates an exploded view of a semi-circular putter type golf club head. FIG. 4B illustrates an isometric view of the semi-circular putter type golf club head of FIG. 4A. FIG. 4C illustrates a side view of the semi-circular putter type golf club head of FIG. 4A. FIG. 5A illustrates an exploded view of another semi-circular putter type golf club head. FIG. 5B illustrates an isometric view of the semi-circular putter type golf club head of FIG. 5A. FIG. 5C illustrates a side view of the semi-circular putter type golf club head of FIG. 5A. FIG. 6A illustrates an exploded view of a winged putter type golf club head. FIG. 6B illustrates an isometric view of the winged putter type golf club head of FIG. 6A. FIG. 6C illustrates a side view of the winged putter type golf club head of FIG. 6A. FIG. 7A illustrates an exploded view of a spade putter type golf club head. FIG. 7B illustrates an isometric view of the spade putter type golf club head of FIG. 7A. FIG. 7C illustrates a side view of the spade putter type golf club head of FIG. 7A. FIG. 7D illustrates a bottom perspective view of the spade putter type golf club head of FIG. 7A. FIG. 8A illustrates an exploded view of a T-shaped putter type golf club head with periphery spans. FIG. 8B illustrates an isometric view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 8C illustrates a side view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 8D illustrates a bottom perspective view of the T-shaped putter type golf club head with periphery spans of FIG. 8A. FIG. 9A illustrates an exploded view of a dual rail putter type golf club head. FIG. 9B illustrates an isometric view of the dual rail putter type golf club head of FIG. 9A. FIG. 9C illustrates a side view of the dual rail putter type golf club head of FIG. 9A. FIG. 9D illustrates a bottom perspective view of the dual rail putter type golf club head of FIG. 9A. FIG. 10A illustrates an exploded view of a circular putter type golf club head. FIG. 10B illustrates an isometric view of the circular putter type golf club head of FIG. 10A. FIG. 10C illustrates a side view of the circular putter type golf club head of FIG. 10A. FIG. 10D illustrates a bottom perspective view of the circular putter type golf club head of FIG. 10A. FIG. 11A illustrates an exploded view of a putter type golf club head comprising a strike face insert having a single component system. FIG. 11B illustrates an exploded view of a putter type golf club head comprising a strike face having a two-component system. FIG. 11C illustrates a front view of a putter type golf club head comprising a strike face insert according to a third embodiment. FIG. 12A illustrates a top perspective view of a two-part putter type club head comprising a sole plate. FIG. 12B illustrates a sole view of the two-part putter of FIG. 12A. FIG. 12C illustrates an exploded view of the two-part putter of FIG. 12A. FIG. 12D illustrates a bottom view of the two-part putter of FIG. 12A with the lower portion removed. FIG. 12E illustrates a heel view of the two-part putter of FIG. 12A. FIG. 13A illustrates a rear perspective view of a two-part putter type club head comprising a pocket. FIG. 13B illustrates an exploded view of the two-part putter of FIG. 13A. FIG. 13C illustrates a sole view of the two-part putter of FIG. 13A. FIG. 13D illustrates a heel view of the two-part putter of FIG. 13A with the lower portion removed. FIG. 13E illustrates a toe view of the two-part putter of FIG. 13A with the lower portion removed. FIG. 14A illustrates a top perspective view of a two-part putter head comprising a ball retrieval feature according to a first embodiment. FIG. 14B illustrates a bottom perspective view of the putter head of FIG. 14A. FIG. 14C illustrates an exploded view of the putter head of FIG. 14A. FIG. 14D illustrates an exploded view of the putter head of FIG. 14A. FIG. 14E illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a second embodiment. FIG. 14F illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a third embodiment. FIG. 14G illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a fourth embodiment. FIG. 14H illustrates a bottom perspective view of a two-part putter head comprising a ball retrieval feature according to a fifth embodiment. FIG. 15A illustrates a rear perspective view of a two-part putter head comprising a ball-outlining alignment aid. FIG. 15B illustrates a rear perspective exploded view of the two-part putter head of FIG. 15A. FIG. 15C illustrates a bottom view of the two-part putter head of FIG. 15A. FIG. 15D illustrates a top view of the two-part putter head comprising the ball-outlining alignment aid of FIG. 15A. FIG. 15E illustrates a top view of the two-part putter head comprising a ball-outlining alignment aid according to a second embodiment. FIG. 15F illustrates a top view of the two-part putter head comprising a ball-outlining alignment aid according to a third embodiment. FIG. 16A illustrates a front perspective view of a putter head comprising a separate toe mass and heel mass. FIG. 16B illustrates a rear perspective exploded view of the putter head of FIG. 16A. FIG. 16C illustrates a sole view of the putter head of FIG. 16A. FIG. 16D illustrates a bottom view of the toe mass and heel mass of the putter head of FIG. 16A. FIG. 17A illustrates a rear perspective exploded view of a two-part blade-type putter head according to a first embodiment. FIG. 17B illustrates a rear perspective exploded view of a two-part blade-type putter head according to a second embodiment with an aperture through the strike face. FIG. 17C illustrates a rear perspective view of the two-part blade-type putter head of FIG. 17A. FIG. 17D illustrates a front perspective view of the upper portion of the two-part blade-type putter head of FIG. 17A. FIG. 17E illustrates a front perspective view of the two-part blade-type putter head of FIG. 17B. FIG. 18A illustrates a rear perspective exploded view of a three-part putter head according to one embodiment. FIG. 18B illustrates a rear perspective view of the three-part putter head of FIG. 18A. FIG. 18C illustrates a bottom perspective view of the three-part putter head of FIG. 18A with the lower portion removed. FIG. 18D illustrates a sole view of the three-part putter head of FIG. 18A.

[0008] Figures 1 to 14, 17 and 18 are provided for explanation only. Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.DESCRIPTIONI. Putter Golf Club Head

[0009] Described herein is a two-part putter head having an upper portion made of a first material such as low density metal (i.e., aluminum, but not limited to) and a lower portion made of a second material, such as a high density metal (i.e., steel, but not limited to). The upper portion has a crown that spans from a strike face to a back edge. This upper portion is affixed to the lower portion and is farther from a ground plane than the lower portion. The lower portion, in most embodiments, has less than 35% of the total solid volume of the putter head, but greater than 45% of the mass. The lower portion provides a peripheral construction and a sole. This combination of peripheral construction and high density lower portion, results in an increase in MOI of at least 30%, over a putter with the same volume, mass, and single material construction (i.e., a putter milled of a single material such as a steel putter or a putter investment cast of a single material).

[0010] The lower portion of the two-part putter head further comprises a sole plate. The sole plate is formed from a high-density material. As described in more detail below, the two-part putter head includes the upper portion and the lower portion comprising the sole plate. The lower portion comprising the sole plate comprises mass structures, ball retrieval features, and / or ball outlining alignment aids to improve the putter experience. The putter heads including the upper portion and the lower portion comprising the sole plate provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye. The putter heads including the upper portion and the lower portion comprising the sole plate further provides consistent ball speed and ball travel distance for repeated putts.

[0011] The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0012] The terms "left," "right," "front," "back," "upper," "lower," "over," "under," "top," "bottom," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the apparatus, methods, and / or articles of manufacture described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

[0013] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways.

[0014] In many embodiments, the golf club head can comprise a putter-type golf club head (the putter type golf club head 100, 200, 300 400 ... etc.). FIGS. 1-12B illustrate multiple embodiments of a putter-type golf club head having an upper portion and lower portion that are separately made of different materials and coupled together and provided for explanation only to aid an understanding of the invention. The putter-type golf club head can be a mallet-type putter head, 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.

[0015] In many embodiments, the putter-type golf club head can have a loft angle less than 10 degrees. In many embodiments, the loft angle of the club head can be between 0 and 5 degrees, between 0 and 6 degrees, between 0 and 7 degrees, or between 0 and 8 degrees. For example, the loft angle of the club head can be less than 10 degrees, less than 9 degrees, less than 8 degrees, less than 7 degrees, less than 6 degrees, or less than 5 degrees. For 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.

[0016] The putter-type golf club head comprises an upper portion and a lower portion. The golf club head can comprise a toe end and a heel end opposite the toe end. The putter-type golf club head can comprise a strike face. The putter-type golf club head can comprise a rear wall opposite the strike face. Further, the putter-type golf club head can comprise an alignment feature. Furthermore, the putter-type golf club head can comprise 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.

[0017] The upper portion is made of a first material. The lower portion is made of a second material. The first material is different than 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.

[0018] In many embodiments, the putter-type golf club head can have a mass that ranges between 340 and 385 grams. In other embodiments, the mass of the putter-type golf club head can range between 340 grams - 345 grams, 345 grams - 350 grams, 350 grams - 355 grams, 355 grams - 360 grams, 360 grams - 365 grams, 365 grams - 370 grams, 370 grams - 375 grams, 375 grams - 380 grams, or 380 grams - 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, 380 grams, 381 grams, 382 grams, 383 grams, 384 grams, or 385 grams.

[0019] In many embodiments, the putter type golf club head can comprise a club head volume ranging between 25 cc and 125 cc. In some embodiments, the club head volume can range between 25 cc - 30 cc, 30 cc - 35 cc, 35 cc - 40 cc, 40 cc - 45 cc, 45 cc - 50 cc, 50 cc - 55 cc, 55 cc - 60 cc, 60 cc - 65 cc, 65 cc - 70 cc, 70 cc - 75 cc, 75 cc - 80 cc, 80 cc - 85 cc, 85 cc - 90 cc, 90 cc - 95 cc, 95 cc - 100 cc, 100 cc - 105 cc, 105 cc - 110 cc, 110 cc - 115 cc, 115 cc - 120 cc, or 120 cc - 125 cc. In one embodiment, the club head volume can range between 40 cc - 110 cc. In some embodiments, the club head volume can be greater than 25 cc, greater than 50 cc, greater than 75 cc, or greater than 100 cc.

[0020] In some embodiments, the putter type golf club head can comprise a strike face made of the first material. In other embodiments, the strike face can be made of the second material. In these embodiments, the material of the strike face can be 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 any metal suitable for creating a golf club head. According to the invention, the strike face is integrally formed to the upper portion. In other examples useful for understanding the invention, but which are not covered by the appended claims, the strike face can be integrally formed to the lower portion. The strike face can be integrally formed to the club head by co-molding, injection molding, casting, additive manufacturing or other forming process.

[0021] FIGS. 11A - 11C illustrate various strike face features 1100 used on the multi-component putters described in this disclosure for information only and to aid a general understanding of the invention. As described in more detail below, the strike face features 1100 can comprise a single component system, a two-component system, or a single component system in combination with a metal portion. The single component system comprises a single strike face insert or component. The two-component system comprises multiple strike face inserts or components. In many embodiments, the strike face features 1100 can comprise a strike face insert. In these embodiments, the strike face is independently formed prior to being coupled to the club head. The side of the strike face insert that will contact the club head can comprise geometry complementary to the geometry of the corresponding portion of the club head that will contact the strike face. In some embodiments, the strike face insert can be made of the first material or the second material. In other embodiments, the strike face insert can be made of a third material. In some embodiments, the strike face insert can be integrally formed with the upper portion or the lower portion. In other embodiments, the strike face insert can be separately formed from both the upper portion and the lower portion.

[0022] The strike face can be secured to the club head by being integrally formed to a portion of the club head or by a fastening means. In some embodiments, the strike face is secured to the upper portion. In these embodiments, the upper portion defines an insert cavity 1110 in a forward portion of the upper portion. The upper portion insert cavity 1110 is configured to receive the strike face insert. Further, in these embodiments, when the strike face insert is affixed to the upper portion, the upper portion encompasses and mates with the insert cavity 1110. In other embodiments, the strike face can be secured to the lower portion. In these embodiments, the lower portion can comprise an insert cavity (not shown). The lower portion insert cavity functions to receive the strike face insert. Further, in these embodiments, when the insert is affixed to the lower portion, the lower portion encompasses and mates with the insert cavity. The strike face can be secured by an adhesive such as glue, very high bond (VHB ™< ) tape, epoxy or another adhesive. Alternately or additionally, the strike face can be secured by welding, soldering, screws, rivets, pins, mechanical interlock structure, or another fastening method.

[0023] The strike face insert can comprise any one or layered combination of the following: aluminum, stainless steel, copper, thermoplastic co-polyester elastomer (TPC), thermoplastic elastomer (TPE), thermoplastic urethane (TPU), steel, nickel, TPU / aluminum, TPE / aluminum, plastic / metal screen insert, polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, PEBAX ®< , or any other desired material. PEBAX ®< is a polyether block amide that is a thermoplastic elastomer made of a flexible polyether and rigid polyamide. The rigid polyamide can comprise Nylon. The PEBAX ®< can comprise different compounds that correspond to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, the PEBAX ®< can comprise a PEBAX ®< 4033 (Arkema, Paris France) or a PEBAX ®< 6333 (Arkema, Paris France). The PEBAX ®< 4033 (Arkema, Paris France) comprises a tetramethylene oxide (53% wt) and a Nylon 12. The PEBAX ®< 6333 (Arkema, Paris France) comprises a Nylon 11. In some embodiments, the face insert can comprise a material such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials or any combination thereof.

[0024] The PEBAX ®< can comprise a percentage of polyether by volume. In some embodiments, the PEBAX ®< can comprise 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 30% to 50%, 30% to 60%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% polyether by volume. For example, the PEBAX ®< can comprise 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% of polyether by volume. In some embodiments, the PEBAX ®< can comprise 0% to 10%, 10% to 20%, 15% to 30%, 20% to 30%, 30% to 40%, 40% to 50%, 40% to 60%, 50% to 60%, or 60% to 70% of polyamide by volume. For example, the PEBAX ®< can comprise 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70% of polyamide by volume. As the percentage of polyether percentage increases, the hardness of the PEBAX ®< decreases. As the percentage of polyamide percentage increases, the hardness of the PEBAX ®< increases. For example, the PEBAX ®< 4033 (Arkema, Paris France) can comprise 40% to 60% polyether by volume and 15% to 30% polyamide by volume. For example, the PEBAX ®< 6333 (Arkema, Paris France) can comprise 15% to 30% polyether by volume and 40% to 60% polyamide by volume.

[0025] In many embodiments, the PEBAX ®< can comprise a hardness ranging from Shore 25D to Shore 75D. In some embodiments, the hardness of the PEBAX can range from Shore 25D to Shore 35D, Shore 35D to Shore 45D, Shore 36D to Shore 44D, Shore 38D to Shore 42D, Shore 45D to Shore 55D, Shore 55D to Shore 65D, Shore 56D to Shore 64D, Shore 60D to Shore 65D, or Shore 65D to Shore 75D. For example, the hardness of the PEBAX can be Shore D 25, 30, 35, 40, 45, 50, 55, 60, 65, or 70.

[0026] In many embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a lower hardness than the PEBAX ®< 6333 (Arkema, Paris France). In many embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a hardness range of Shore 35D to Shore 55D. In some embodiments, the PEBAX ®< 4033 (Arkema, Paris France) can comprise a hardness range of Shore 38D to Shore 42D, or Shore 39D to Shore 41D. For example, the PEBAX ®< 4033 (Arkema, Paris France) can be comprise a Shore D hardness of 40. In many embodiments, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a hardness range of Shore 50D to Shore 75D. In some embodiments, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a hardness range of Shore 55D to Shore 70D, or Shore 60D to Shore 65D. For example, the PEBAX ®< 6333 (Arkema, Paris France) can comprise a Shore D hardness of 63.

[0027] As illustrated in FIG. 11A, the strike face features 1100 can comprise a strike face insert system 1120. The strike face insert system 1120 can be a single component system comprising a ball striking layer 1122 and an adhesive layer 1124. The strike face insert 1120 is configured to be adhered into the insert cavity 1110 via the adhesive layer 1124. The strike face insert 1120 can comprise a polymer type material as described in this disclosure. The strike face insert 1120 can comprise a PEBAX ®< as described in this disclosure.

[0028] As illustrated in FIG. 11B, the strike face features 1100 can comprise a strike face insert system 1130. The strike face insert system 1130 can be a two-component system comprising a ball striking face plate 1132 and a face insert base 1134. The strike face insert 1130 having the two-component system is configured to be received in the insert cavity 1110 via one or more adhesive layers. The ball striking face plate 1132 of the strike face insert 1130 can comprise a first insert material. The face insert base 1134 of the strike face insert 1130 can comprise a second insert material. In many embodiments, the first insert material of the ball striking face plate 1132 and the second material of the face insert base 1134 can be different. In some embodiments, the first insert material of the ball striking face plate 1132 and the second insert material of the face insert base 1134 can be similar. In many embodiments, the first insert material of the ball striking face plate 1122 can comprise a polymer type material. In some embodiments, the first insert material of the ball striking face plate 1122 can comprise a metallic material. In many embodiments, the second insert material of the face insert base 1134 can comprise a polymer type material.

[0029] The first insert material can comprise a metal such as steel, steel alloys, tungsten, tungsten alloys, aluminum, aluminum alloys, titanium, titanium alloys, vanadium, vanadium alloys, chromium, chromium alloys, cobalt, cobalt alloys, nickel, nickel alloys, other metals, other metal alloys, composite polymer materials or any combination thereof.

[0030] The first insert material or the second insert material can comprise a polymer type material. The polymer type material can comprise polyethylene, polypropylene, polytetrafluoroethylene, polyisobutylene, polyvinyl chloride, or any other polymer type material. In many embodiments, the face insert can comprise a PEBAX ®< . More specifically, the PEBAX ®< is a polyether block amide that is a thermoplastic elastomer made of a flexible polyether and rigid polyamide. The rigid polyamide can comprise Nylon. The PEBAX ®< can comprise different compounds that correspond to different Shore D hardness values, polyether percentages, and / or polyamide percentages. In many embodiments, the PEBAX ®< can comprise a PEBAX ®< 4033 (Arkema, Paris France) or a PEBAX ®< 6333 (Arkema, Paris France). The PEBAX ®< 4033 (Arkema, Paris France) comprises a tetramethylene oxide (53% wt) and a Nylon 12. The PEBAX ®< 6333 (Arkema, Paris France) comprises a Nylon 11. The first insert material and the second insert material can comprise similar polyether percentages, polyamide percentages, or Shore D hardness values as described above.

[0031] The ball striking face plate 1132 of the strike face insert 1130 can comprise a thickness. In many embodiments, the thickness of the ball striking face plate 1132 can range from 0.381mm to 2.921mm (0.015 to 0.115 inch). In some embodiments, the thickness of the ball striking face plate 1132 can range from 0.381mm to 1.143mm (0.015 to 0.045 inch), 0.508mm to 1.27mm (0.020 to 0.050 inch), 0.635mm to 1.397mm (0.025 to 0.055 inch), 1.27mm to 2.54mm (0.050 to 0.100 inch), 1.397mm to 2.667mm (0.055 to 0.105 inch), 1.524 to 2.794mm (0.060 to 0.110), or 1.651mm to 2.921mm (0.065 to 0.115 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be at least 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be greater than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be less than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch). For example, the thickness of the ball striking face plate 1132 can be 0.381, 0.508, 0.635, 0.762, 0.889, 1.016, 1.143, 1.27, 1.397, 1.524, 1.651, 1.778, 1.905, 2.032, 2.159, 2.286, 2.413, 2.54, 2.667, 2.794, or 2.921 mm (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 inch).

[0032] In other embodiments, the thickness of the ball striking face plate 1132 can range from 2.921mm to 10.16mm (0.115 to 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can range from 2.921mm to 5.08mm (0.115 to 0.20 inch), 3.81mm to 7.62mm (0.15 to 0.30 inch), 5.08mm to 7.62mm (0.20 to 0.30 inch), 6.35 to 8.89mm (0.25 to 0.35 inch), or 7.62mm to 10.16mm (0.30 to 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be at least 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be greater than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). In some embodiments, the thickness of the ball striking face plate 1132 can be less than or equal to 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch). For example, the thickness of the ball striking face plate 1132 can be 0.381, 0.508, 0.635, 0.762, 0.889, or 1.016mm (0.15, 0.20, 0.25, 0.30, 0.35, or 0.40 inch).

[0033] The face insert base 1134 of the strike face insert 1130 can comprise a thickness. In many embodiments, the thickness of the face insert base 1134 can range from 1.27mm to 5.08mm (0.05 to 0.20 inch). In some embodiment, the thickness of the face insert base 1134 can range from 1.27mm to 2.54mm (0.05 to 0.10 inch), or 2.54mm to 5.08mm (0.10 to 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be at least 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be greater than or equal to 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). In some embodiments, the thickness of the face insert base 1134 can be less than or equal to 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch). For example, the thickness of the face insert base 1134 can be 1.27mm, 2.54mm, 3.81mm, or 5.08mm (0.05, 0.10, 0.15, or 0.20 inch).

[0034] In other embodiments, the thickness of the face insert base 1134 can range from 5.08mm to 20.32mm (0.20 to 0.80 inch). In some embodiments, the thickness of the face insert base 1134 can range from 5.08mm to 12.7mm (0.20 to 0.50 inch), 7.62mm to 15.24mm (0.30 to 0.60 inch), 10.16mm to 17.78mm (0.40 to 0.70 inch), or 12.7mm to 20.32mm (0.50 to 0.80 inch). In some embodiment, the thickness of the face insert base 1134 can range from 5.08mm to 10.16mm (0.20 to 0.40 inch), 7.62mm to 12.7mm (0.30 to 0.50 inch), 10.16mm to 15.24mm (0.40 to 0.60 inch), 12.7mm to 17.78mm (0.50 to 0.70 inch), or 15.24mm to 20.32mm (0.60 to 0.80 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be at least 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be greater than or equal to 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). In some embodiments, the face insert base 1134 of the strike face insert 1130 can be less than or equal to 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch). For example, the thickness of the face insert base 1134 can be 5.08, 6.35, 7.62, 8.89, 10.16, 11.43, 12.7, 13.97, 15.24, 16.51, 17.78, 19.05, or 20.32mm (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 inch).

[0035] As illustrated FIG. 11C, the strike face features 1100 can comprise a strike face insert system 1140. The strike face insert system 1140 comprise a strike face insert 1144 and a metal portion 1142. The strike face insert 1144 comprises a single component system described above. The metal portion 1142 surrounds the strike face insert 1144. The strike face insert 1144 can be formed from a polymer material described in this disclosure. The strike face insert 1144 is further surrounded by an epoxy border 1146. The epoxy border 1146 extends around a perimeter of the strike face insert 1144. The combination of the strike face insert 1144 formed from a polymer type material and the epoxy border 1146 can provide enhanced feel and sound during impacts with a golf ball. Further, removing material from the strike face or the upper portion to accommodate the strike face insert 1144 reduces the putter head weight at or near a center area of the putter head. Removing material from the center area and / or forward area of the putter head allows for more weight to be positioned in the perimeter of the putter head thereby increasing moment of inertia and forgiveness.

[0036] The epoxy border 1146 surrounding the strike face insert 1144 can comprise a width. The width of the epoxy border 1146 can be measured as a transverse width. In many embodiments, the width of the epoxy border can range from 0.254mm to 2.032mm (0.01 inch to 0.08 inch). In some embodiments, the width of the epoxy border 1146 can range from 0.254mm to 1.016mm (0.01 inch to 0.04 inch), or 1.016mm to 2.032mm (0.04 inch to 0.08 inch). In some embodiments, the width of the epoxy border 1146 can range from 0.508mm to 1.27mm (0.02 inch to 0.05 inch), 0.762mm to 1.524mm (0.03 inch to 0.06 inch), 1.016mm to 1.778mm (0.04 inch to 0.07 inch), or 1.27mm to 1.778mm (0.05 inch to 0.07 inch). For example, the width of the epoxy border can be 0.254, 0.508, 0.762, 0.889, 1.016, 1.143, 1.27, 1.524, 1.778, or 2.032 mm (0.01, 0.02, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, or 0.08 inch). In one example, the width of the epoxy border 1146 can be 0.762mm (0.03 inch).

[0037] The metal portion 1142 can further comprise a milling pattern 1148. The milling pattern 1148 can comprise a plurality of milling lines that extend in a vertical, horizontal, curvilinear, arcuate, or circular direction across the strike face. The milling pattern 1148 can extend in a crown to sole direction, and / or in a heel to toe direction across the strike face. The milling pattern 1148 enhances the surface finish of the putter head or strike face to improve the appearance of the putter head.

[0038] The strike face insert systems (1120, 1130, 1140) described in this disclosure can be formed by a number of different processes. The different forming processes include the following: injection molding, casting, blow molding, compression molding, co-molding, laser forming, film insert molding, gas assist molding, rotational molding, thermoforming, laser cutting, 3-D printing, forging, stamping, electroforming, machining, molding, or any combination thereof. Further, the strike face insert can have any combination of hardness, volume, thickness, and forming processes described above.

[0039] In many embodiments, the upper portion of the putter-type golf club head having the first material comprises a first density ranging between 1.0 g / cc and 6.0 g / cc. The first density can range between 2.0 g / cc to 5.0 g / cc. In some embodiments, the first density can range between 1.0 - 1.25 g / cc, 1.25 - 1.5 g / cc, 1.5 - 1.75 g / cc, 1.75 - 2.0 g / cc, 2.0 - 2.25 g / cc, 2.25 - 2.5 g / cc, 2.5 - 2.75 g / cc, 2.75 - 3.0 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, 4.25 - 4.5 g / cc, 4.5 - 4.75 g / cc, 4.75 - 5.0 g / cc, 5.0 - 5.25 g / cc, 5.0 - 5.25 g / cc, 5.25 - 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 range between 2.0 - 3.0 g / cc. In some embodiments, the first density can be less 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, or 6.0 g / cc.

[0040] In many embodiments, the lower portion of the putter-type golf club head having the second material. The second material can comprise a density. The density is a second density to the first density of the first material in the upper portion. The second density of the second material of the lower portion can range between 7.0 g / cc and 20.0 g / cc. In some embodiments, the second density can range between 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 - 15.5 g / cc, 15.5 - 16.0 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 range between 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 2 times greater than the first density, at least 3 times greater than the first density, at least 4 times greater than the first density, or at least 5 times greater than 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.

[0041] The upper portion of the putter-type golf club having the first material can 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 any metal suitable for creating a golf club head. In many embodiments, the upper portion is made of aluminum alloy or ADC-12.

[0042] The lower portion of the putter-type golf club having the second material can 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 any metal suitable for creating a golf club head. 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 and upper portion are not made from the same one material or the same combination of materials.

[0043] Furthermore, the upper and lower portion of the putter-type golf club head can be joined in any one or combination of the following methods: welding, soldering, brazing, swedging, adhesion, epoxy, or mechanical fastening. In some embodiments, the upper and lower portion can be joined by adhesion with epoxy, polyurethanes, resins, hot melts, or any other adhesive.II. Embodiments a. Blade Embodiment

[0044] Referring to FIGS. 1A and 1B, a blade type putter head 100 is shown for information only and to aid a general understanding of the invention. The putter head 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 lower portion 108 combine to create a balanced putter head 100, while maintaining a desirable volume and mass.b. Blade Embodiment with Heel and Toe Mass

[0045] Referring to FIGS. 17A-17E, a blade type putter head 1700 is shown for explanation only to aid an understanding of the invention and has an upper portion 1704 and a lower portion 1708. The upper portion 1704 is made from a first material having a first density and the lower portion 1708 is made from a second material having a second density. The first density is less than the second density. The two-part blade type putter head 1700 is formed by an upper portion 1704 that overlays the back end of the lower portion 1708 without disturbing the strike face 1720. The upper portion 1704 and lower portion 1708 combine to create a balanced putter head 1700 with a high moment of inertia (3500 g·cm 2< - 5000 g·cm 2< ), while maintaining a desirable volume and mass.c. Crescent Embodiment

[0046] Referring to FIG. 3A-3C, a crescent-shaped putter head 300 is shown for explanation only to aid an understanding of the invention and has a upper portion 304 and a lower portion 308. The upper portion 304 is made from a first material have 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 lower portion 308 combine to create a balanced putter head 300, while maintaining a desirable volume and mass. The high density lower portion 308 and low density upper portion 308, place more mass near the peripheries of the putter head 300, thus increasing the MOI and stability over a putter with the same volume, mass, and single material construction.d. Semi-Circular Embodiment

[0047] Referring to FIG. 4A-4C, a semi-circular putter head 400 is shown for explanation only to aid an understanding of the invention and has an upper portion 404 and a lower portion 408. The upper portion 404 is made from a first material have 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 lower portion 408 combine to create a high-MOI putter head 400 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.e. Winged Embodiment

[0048] Referring to FIG. 6A and 6B, a winged shaped putter head 600 is shown for explanation only to aid an understanding of the invention and has a upper portion 604 and a lower portion 608. The upper portion 604 is made from a first material have 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 lower portion 608 combine to create a high-MOI putter head 600 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.f. Spade Embodiment

[0049] Referring to FIG. 7A and 7B, a spade shaped putter head 700 is shown for explanation only to aid an understanding of the invention and has a upper portion 704 and a lower portion 708. The upper portion 704 is made from a first material have 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 lower portion 708 combine to create a high-MOI putter head 700 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.g. T-Shaped Embodiment with Periphery Spans

[0050] Referring to FIGS. 8A and 8B, a T-shaped putter head with periphery spans 800 is shown for explanation only to aid an understanding of the invention, and has a upper portion 804 and a lower portion 808. The upper portion 804 is made from a first material have 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 lower portion 808 combine to create a high-MOI putter head 800 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.h. Dual-Rail Embodiment

[0051] Referring to FIGS. 9A and 9B, a dual-rail putter head 900 is shown for explanation only to aid an understanding of the invention and has a upper portion 904 and a lower portion 908. The upper portion 904 is made from a first material have 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 lower portion 908 combine to create a high-MOI putter head 900 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.i. Circular Embodiment

[0052] Referring to FIG. 10A-10C, a circular putter head 1000 is shown for explanation only to aid an understanding of the invention and has an upper portion 1004 and a lower portion 1008. The lower portion 1008 is made from a first material have 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 lower portion 1008 combine to create a high-MOI putter head 1000 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.III. Sole Plate Embodiments

[0053] Described below for information only and to aid an understanding of the invention are additional multi-component putter heads comprising an upper portion and a lower portion. The lower portion further comprises a sole plate formed from a high-density material, and the upper portion is formed from a low-density material. The material density of the upper portion is less than the material density of the lower portion including the sole plate. The sole plates described below comprise mass structures, ball retrieval features, and / or ball outlining alignment aids to provide more consistent and more forgiving putts. As described below, the putter heads including the upper portion and the lower portion comprising the sole plate provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye to create a consistent putting stroke. Further, the putter heads including the upper portion and the lower portion comprising the sole plate provides consistent ball speed and ball travel distance for repeated putts.a. Putter Head with Sole Plate having Heel and Toe Mass

[0054] Referring to FIGS. 12A - 12E, a semi-circular putter head 1200 is shown for explanation only to aid an understanding of the invention and has an upper portion 1204 and a lower portion 1208. The upper portion 1204 is formed from a first material have a first density and the lower portion 1208 is made from a second material having a second density. The first density is less than the second density. The sole plate of the putter head 1200 increases perimeter weighting and MOI. The upper portion 1204 and lower portion 1208 combine to create a high-MOI putter head 1200 (3000 g·cm 2< - 4000 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1200 can have a MOI ranging from 3000 g·cm 2< - 3500 g·cm 2< or 3500 g·cm 2< - 4000 g·cm 2< . The putter head 1200 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1200 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.b. Putter Head with Pocket and Sole Plate

[0055] illustrated in FIGS. 13A - 13E, a putter head 1300 having a pocket and a sole plate is shown for explanation only to aid an understanding of the invention. As described in more detail below, the pocket of putter head 1300 allows weight to be removed from the putter head 1300 and the sole plate allows for increased perimeter weighting. The putter head 1300 comprises an upper portion 1304 and a lower portion 1308. The upper portion 1304 is formed from a first material having a first density and the lower portion 1308 is formed from a second material having a second density. The first density is less than the second density. The upper portion 1304 and the lower portion 1308 combine to create a high-MOI putter head (4000 g·cm 2< - 5500 g·cm 2< ), while maintain a desirable volume and mass. For example, the putter head 1300 can have an MOI ranging from 4000 g·cm 2< - 4500 g·cm 2< , 4500 g·cm 2< - 5000 g·cm 2< , or 5000 g·cm 2< - 5500 g·cm 2< . The putter head 1300 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1300 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.c. Putter Head with Sole Plate and Ball Retrieval Feature

[0056] Referring to FIGS. 14A-14D, a mallet type putter head is shown for explanation only to aid an understanding of the invention. The putter head 1400 comprises an upper portion 1404 and a lower portion 1408. The lower portion 1408 is a sole plate comprising a toe mass 1446, a heel mass 1448, and a rear mass 1450. The putter head 1400 further comprises a ball retrieval feature 1422. The ball retrieval feature 1422 is configured to pick up and retain a golf ball. The ball retrieval feature and sole plate increase the perimeter weighting thereby increasing the MOI and forgiveness of the putter head 1400. The putter head 1400 can have an MOI ranging from 4000 g·cm 2< - 5000 g·cm 2< . For example, the putter head 1400 can have an MOI ranging from 400 g·cm 2< - 4500 g·cm 2< or 4500 g·cm 2< - 5000 g·cm 2< . The putter head 1400 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1400 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.d. Putter Head with Ball-Outlining Alignment Aid and Sole Plate

[0057] In one embodiment, the putter-type golf club head comprises a two-part construction and includes an alignment aid having a ball-outlining feature. The two-part construction allows the putter-type club head to be formed from multiple materials. Referring to FIGS. 15A and 15B, the putter-type golf club head 1500 comprises an upper portion 1504 and a lower portion 1508. The upper portion 1504 is affixed to the lower portion 1508. The upper portion 1504 is formed from a first material having a first density, and the lower portion 1508 is formed from a second material having a second density. In some embodiments, the first density is less than the second density. As discussed in more detail below, the upper portion 1504 and the lower portion 1508 combine to create a high-MOI putter-type club head 1500 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1500 can have an MOI ranging from 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , 6000 g·cm 2< - 6500 g·cm 2< . The putter head 1500 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1500 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.

[0058] The putter-type club head 1500 further comprises a crown 1536, a sole 1568, a strike face 1520, a rear end 1534, a toe end 1512, and a heel end 1516. The outermost points of the strike face 1520, the rear end 1534, the toe end 1512, and the heel end 1516 define a perimeter 1510 of the putter-type club head 1500. The upper portion 1504 and the lower portion 1508 are affixed together and each form a portion of the crown 1536, a portion of the sole 1568, a portion of the toe end 1512, a portion of the heel end 1516, and a portion of the perimeter 1510. The crown 1536 gradually slopes from the strike face 1520 to the rear end 1534 such that the putter-type club head 1500 is thicker near the strike face 1520 and gradually thins towards the rear end 1534. The slope of the crown 1536 can be linear, curvilinear, parabolic, sinusoidal, or a function of polynomial. Further, the strike face 1520 comprises a strike face center point equidistant from the heel end 1516 and toe end 1512, as well as equidistant from the crown 1536 and the sole 1568.

[0059] In many embodiments, the sole 1568 can be planar. In some embodiments, the sole 1568 can have a slight arch in a heel end 1516 to toe end 1512 direction, wherein the slight arch can be linear, or a function of a polynomial. In some embodiments, the sole 1568 can have a strong arch in the heel end 1516 to toe end 1512 direction, wherein the strong arch can be linear, or a function of a polynomial. The sole 1568 functions to provide a surface to rest the putter-type club head 1500 on the ground plane 1590. As discussed above, the putter-type club head 1500 comprises an upper portion 1504 and a lower portion 1508, where the lower portion 1508 forms a majority of the sole 1568 and rests on the ground plane. The upper portion 1504 sits above the lower portion 1508 when the putter-type club head 1500 is assembled.

[0060] As discussed above, the upper portion 1504 comprises a low-density material (i.e., the first material). In many embodiments, the upper portion 1504 is formed from aluminum. The upper portion 1504 is affixed to the lower portion 1508 to define the crown 1536, the sole 1568, the toe end 1512, the heel end 1516, and the perimeter 1510. The upper portion 1504 comprises an upper portion top surface 1526 and an upper portion bottom surface 1528, where the upper portion top surface 1526 forms a portion of the crown 1536, and the upper portion bottom surface 1528 forms a portion of the sole 1568. The upper portion 1504 further comprises a forward portion 1522 and a rearward extension 1524. The forward portion 1522 comprises the strike face 1520. The rearward extension 1524 extends rearward from the forward portion 1522 towards the rear end 1534. The rearward extension 1524 is generally perpendicular to the strike face 1520 such that the forward portion 1522 and the rearward extension 1524 form a T-shape.

[0061] The forward portion 1522 comprises rear walls opposite the strike face 1520 near the heel end 1516 and the toe end 1512. The rearward extension 1524 comprises side walls near the heel end 1516 and the toe end 1512. The rear wall and side wall near the toe end 1512 define a toe wall 1529, and the rear wall and side wall near the heel end 1516 define a heel wall 1530. The toe wall 1529 and the heel wall 1530 that frame the T-shape of the upper portion 1504. Further, the toe and heel walls 1529, 1530 define cutout regions that allow the upper portion 1504 to receive the lower portion 1508. The cutout regions extend inward from the toe end 1512 or the heel end 1516 toward the center of the upper portion 1504. The cutout regions are bounded by the crown 1536, the perimeter 1510, and either the toe wall 1529, or the heel wall 1530. The toe and heel walls 1529, 1530 define a boundary between the cutout regions and the forward portion 1522, as well as a boundary between the cutout regions and the rearward extension 1524. The cutout portions remove mass from the low-density upper portion 1504, which is replaced with the high-density lower portion 1508 to increase the perimeter weighing of the putter-type club head 1500.

[0062] To further reduce the mass of the upper portion 1504, the upper portion 1504 defines a central recess 1570 that extends from the forward portion 1522 to the rear end 1536. The central recess 1570 removes mass from a central portion of the upper portion 1504, thereby allowing mass to be moved toward the perimeter 1510. The central recess 1570 is defined by a recess wall 1572 and a recess floor 1574. The recess floor 1574 is recessed into the upper portion 1504 away from the upper portion top surface 1526, and the recess wall 1572 circumscribes the recess floor 1574. The recess wall 1572 defines a transition between the upper portion top surface 1526 and the recess floor 1574.

[0063] The recess wall 1572 comprises a height. In some embodiments, the recess wall height slopes with the slope of the crown 1536 such that the recess wall height is larger near the strike face 1520 and smaller near the rear end 1534. In such an embodiment, the recess wall 1572 comprises a height near the rear end 1534 such that the recess floor 1574 is not flush with the upper portion top surface 1526. In other embodiments, the recess wall height remains constant throughout the central recess 1570. The recess floor 1574 is parallel to the ground plane to provide a parallel surface to the ground plane for portions of the alignment aid 1544. The central recess 1570 is located near a middle of the putter-type club head 1500 within the forward portion 1522 and the rear extension 1524 to provide a centered feature for the alignment aid 1544. The central recess 1570 further contributes to the alignment aid 1544, as discussed in more detail below.

[0064] Referring to FIG. 15D-15F, the upper portion 1504 further comprises an alignment aid 1544. The alignment aid 1544 extends along the upper portion 1504 from the forward portion 1522 to the rear end 1534. The alignment aid 1544 comprises several features that work, in conjunction with the central recess 1570, to provide the viewer a visual alignment field that extends from the strike face 1520 to the rear end 1534. The goal is to align the entire putter-type club head 1500 with the golf ball using the alignment aid 1544.

[0065] The alignment aid 1544 comprises several corresponding features that are carefully positioned relative to the central recess 1570. Referring to FIGS. 15D-15F, the alignment aid 1544 comprises a ball-outlining feature 1580, a central line 1576, and a plurality of grooves 1578. The ball-outlining feature 1580 is formed integrally with the upper portion 1504. The ball-outlining feature 1580 is centered on the strike face center point and positioned at an offset from the strike face 1520. The ball-outlining feature 1580 is approximately the width of a golf ball [4.27cm (1.68 inches)] to help frame the golf ball during a swing. In some embodiments, the ball-outlining feature 1580 is slightly wider than the width of a golf ball to allow forgiveness when framing the ball. The ball-outlining feature 1580 is generally golf ball shaped near the strike face 1520.

[0066] The ball-outlining feature 1580 is located on the upper portion top surface 1526 above the central recess 1570. However, the ball-outlining feature 1580 generally follows a perimeter of the central recess 1570. The ball-outlining feature 1580 comprises one or more arcuate portions 1582 and a set of parallel lines 1584 connected to the one or more arcuate portions 1582. At least one arcuate portion 1582 arcs near the strike face 1520 and is offset from the strike face 1520. Referring to FIG. 15D, in some embodiments, the ball-outlining feature 1580 comprises two arcuate portions 1582, where one arcuate portion arcs near the strike face 1520, and the other arcs near the rear end 1534. The one or more arcuate portions 1582 generally resemble one half of a golf ball. The parallel lines 1584 extend rearward from the arcuate portion 1582 toward the rear end 1534. The parallel lines 1584 are generally parallel to the rear extension 1524. The parallel lines 1584 are approximately the width of a golf ball [4.27cm (1.68 inches)]. The ball-outlining feature 1580 is generally the width of a golf ball and generally resembles an elongated golf ball to help the viewer visualize the trajectory of the golf ball. The ball-outlining feature is located on the upper portion top surface 1526 and outlines the central recess 1570.

[0067] The ball-outlining feature 1580 partially or fully circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 connect multiple arcuate portions 1582 to form a circular or oblong ball-outlining feature 1580 that fully circumscribes the central recess 1570, as shown in FIG. 15D. In other embodiments having only one arcuate portion 1582, the parallel lines 1584 extend rearward, thereby defining a U-shaped ball-outlining feature 1580 that partially circumscribes the central recess 1570. In some embodiments, the parallel lines 1584 extend fully to the rear end 1534, as shown in FIG. 15E. In other embodiments, the parallel lines 1584 extend partially to the rear end 1534, as shown in FIG. 15F. The ball-outlining feature 1580 generally follows the perimeter of the central recess 1570 and is located on the upper portion top surface 1526.

[0068] In some embodiments, the ball-outlining feature 1580 is recessed into the upper portion 1504 away from the upper portion top surface 1526, thereby defining a channel. However, in other embodiments, the ball-outlining feature 1580 is flush with the upper portion top surface 1526. Further, in other embodiments, the ball-outlining feature 1580 protrudes from the upper portion top surface 1526. The ball-outlining feature 1580 is positioned on the upper portion top surface 1526 outside of the central recess 1570. The alignment aid 1544 further comprises a central line 1576 and a plurality of grooves 1578 located within the central recess 1570. These features can work in conjunction with the ball-outlining feature 1580 to provide the viewer an elongated alignment aid 1544 that extends from the strike face 1520 to the rear end 1534.

[0069] The central line 1576 is located within the central recess 1570 on the recess floor 1574. The central line 1576 is positioned behind the strike face center point and extends through the entire length of the central recess 1570. The central line 1576 extends perpendicularly from the strike face 1520 towards the rear end 1534. The central line 1576 also extends parallel to the parallel lines 1584 of the ball-outlining feature 1580. In some embodiments, the central line 1576 is further recessed into the recess floor 1574. In other embodiments, the central line 1576 is flush with the recess floor 1574. In some further embodiments, the central line 1576 protrudes from the recess floor 1574. The central line 1576 assists the viewer in finding a center of the alignment aid 1544. The central line 1576 is positioned in a middle of the recess floor 1574.

[0070] The alignment aid further comprises a plurality of grooves 1578 that are positioned on the recess floor 1574 on either side of the central line 1576. The plurality of grooves 1578 are further recessed into the recess floor 1574. In some embodiments, the plurality of grooves 1578 are equally spaced apart from each other. In other embodiments, the plurality of grooves 1578 are concentrated near the central line 1576, or near the toe end 1512 and the heel end 1516. The plurality of grooves 1578 are and are parallel to the central line 1576 and the parallel lines 1584 of the ball-outlining feature 1580. The plurality of grooves 1578 provide a series of alignment lines perpendicular to the strike face 1520 that further assist the viewer in correctly aligning the golf ball.

[0071] As discussed above, each feature of the alignment aid 1544 assists the viewer in aligning the putter-type club head 1500 with the golf ball. The ball-outlining feature 1580 is approximately the width of a golf ball and generally resembles an oblong golf ball. The ball-outlining feature 1580 allows the user to outline the edges of the golf ball with the parallel lines to frame the ball. The central line 1576 is located in a middle of the ball-outlining feature 1580 and behind the strike face center point to help the viewer align the center of the golf ball with the center of the putter-type club head 1500. The plurality of grooves 1578 are parallel to the parallel lines 1584 and the central line 1576 and further assist the user in squaring the golf ball with the putter-type club head 1500.

[0072] The alignment aid 1544 further utilizes the central recess 1570. The central recess 1570 provides a structure for the ball-outlining feature 1580 to outline. Further, the central recess 1570 houses the central line 1576 and the plurality of grooves 1578. The ball-outlining feature 1580 is located near the upper portion top surface 1526, and the central line 1576 and the plurality of grooves 1578 are located on the recess floor 1574 at a vertical offset from the ball-outlining feature 1580. In a top-down view of the putter-type club head 1500, the central line 1576 appears slightly offset from the ball-outlining feature. The offset is contributed to the positioning of the ball-outlining feature 1580 on the upper portion top surface 1526 and the central line 1576 on the recess floor 1574. Further, in a top down view, the recess wall 1572 disappears when the putter-type club head 1500 is in alignment, as shown in FIG. 15D. The different portions of the alignment aid 1544 work in conjunction with the central recess 1570 to help the user align the golf ball. The alignment aid 1544 can comprise a plurality of colors to help the viewer identify the different features of the alignment aid 1544.

[0073] Each portion of the alignment aid 1544 comprises a color. The ball-outlining feature 1580 comprises a first color, and the central line 1576 comprises a second color. Further, the upper portion 1504 comprises a third color. The colors can white, black, grey, silver, red, blue, yellow, green, orange, purple, or any other suitable color. In some embodiments, the first, second, and third colors are similar. In other embodiments, the first, second, and third colors are different from one another. The different colors provide a visual contrast between the different features of the alignment aid 1544, which helps the viewer identify the various features.

[0074] In some embodiments, the contrast is defined by colors that are opposite from one another. For example, the first, second, or third colors can be primary colors selected from the group consisting of red, yellow, and blue, while the other of the first, second, or third colors can be secondary colors selected from the group consisting of green, orange, and purple. Alternatively, the first, second, or third colors can be white or black, while the other of the first, second, or third colors can be the other of white or black. The different or contrasting colors of each feature further assist the viewer in alignment by improving the viewer's ability of the brain to detect a malalignment among parallel lines, a phenomenon known as Vernier Acuity.

[0075] The arrangement of the parallel lines 1584 of the ball-outlining feature 1580 and the central line 1576 take advantage the viewer's Vernier Acuity. In some embodiments, the positioning and the contrasting colors of the parallel lines 1584 of the ball-outlining feature 1580 and the central line 1576 keep the viewer's eyes still and allow the viewer's eyes to naturally stay focused on the central line 1576 to better align the golf ball with the target. In some embodiments, the ball-outlining feature 1580 and the central line 1576 are paint-filled. The shading and sizing of the features are selected to provide an alignment aid 1544 that generally resembles a golf ball.

[0076] The ball-outlining feature 1580 defines width measured between the furthest extent of the parallel lines 1584. The width can be slightly larger than the width of a golf ball to allow forgiveness when framing the golf ball. The width is between 4.19cm to 4.57cm (1.65 inches to 1.80 inches). In some embodiments, the width is approximately 4.19cm, 4.22cm, 4.24cm, 4.27cm, 4.29cm, 4.32cm, 4.34cm, 4.37cm, 4.39cm 4.42cm, 4.45cm, 4.47cm, 4.5cm, 4.52cm, 4.66cm, or 4.572cm (1.65 inches, 1.66 inches, 1.67 inches, 1.68 inches, 1.69 inches, 1.70 inches, 1.71 inches, 1.72 inches, 1.73 inches, 1.74 inches, 1.75 inches, 1.76 inches, 1.77 inches, 1.78 inches, 1.79 inches, or 1.80 inches). In one embodiment, the width is approximately 4.5212xm (1.78 inches).

[0077] The ball-outlining feature 1580 further defines a thickness. The thickness can be large enough to provide a substantial ball-outlining feature 1580. The thickness is between 0.762mm and 3.81mm (0.03 inch and 0.15 inch). In some embodiments, the thickness is approximately 0.762mm, 1.016mm, 1.27mm, 1.524mm, 1.778mm, 2.032mm, 2.286mm, 2.54mm, 2.794mm, 3.048mm, 3.302mm, 3.556mm, or 3.81 mm (0.03 inch, 0.04 inch, 0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, or 0.15 inch).

[0078] The ball-outlining feature 1580 further defines a length. The length is measured in a front to rear direction between the end points of the ball-outlining feature 1580. The length is between 7.366cm to 7.874cm (2.9 inches to 3.1 inches). In some embodiments, the length is approximately 7.366 cm, 7.3914 cm, 7.4168 cm, 7.4422 cm, 7.4676 cm, 7.493 cm, 7.5184 cm, 7.5438 cm, 7.5692 cm, 7.5946 cm, 7.62 cm, 7.6454 cm, 7.6708 cm, 7.6962 cm, 7.7216 cm, 7.747 cm, 7.7724 cm, 7.7978 cm, 7.8232 cm, 7.8486 cm, or 7.874 cm (2.90 inches, 2.91 inches, 2.92 inches, 2.93 inches, 2.94 inches, 2.95 inches, 2.96 inches, 2.97 inches, 2.98 inches, 2.99 inches, 3.00 inches, 3.01 inches, 3.02 inches, 3.03 inches, 3.04 inches, 3.05 inches, 3.06 inches, 3.07 inches, 3.08 inches, 3.09 inches, or 3.10 inches). In one embodiment, the length is 7.8232cm (3.08 inches).

[0079] The alignment aid 1544 is designed to provide a golf ball-like feature that is approximately the width of a golf ball. As discussed above, the alignment aid 1544 comprises different features positioned near or within the central recess 1570. Each feature provides a function to the alignment aid 1544, thereby allowing the user to better align the golf ball with the desired spot on the putter-type golf club head to achieve more accurate shots. Further, the alignment aid 1544 utilizes the central recess 1570 to further assist the viewer in alignment. The alignment aid 1544 and the central recess 1570 are located near a middle of the putter-type club head 1500 within the forward portion 1522 and the rear extension 1524. The rear extension 1524 is configured to allow the upper portion 1504 to receive the lower portion 1508.

[0080] The lower portion 1508 comprises a high-density material (i.e., the second material) than the upper portion 1504. In many embodiments, the lower portion 1508 is formed from stainless steel. Referring to FIG. 15B, the lower portion 1508 comprises a central portion 1538, a toe mass 1545, and a heel mass 1547. The central portion 1538 is a thinned region relative to the toe and heel masses 1545, 1547 and allows the upper portion 1504 to be received by the lower portion 1508. The thinned central portion 1538 also removes mass from a center of the lower portion 1508 that can be reallocated to the toe and heel masses 1545, 1547 to improve the moment of inertia of the putter-type club head 1500. The central portion 1538 comprises a central portion top surface 1540 proximate the upper portion bottom surface 1528. The central portion top surface 1540 comprises a corresponding geometry to the upper portion bottom surface 1528. In some embodiments, the central portion top surface 1528 comprises one or more recesses, as shown in FIG. 15B. The one or more recesses can further reduce the mass from a center of the lower portion 1508. The mass can be redistributed to the toe and heel masses 1545, 1547, which are configured to distribute mass to the peripheries of the putter-type club head 1500.

[0081] The toe and heel masses 1545, 1547 are raised portions relative to the central portion 1538. The toe and heel masses 1545, 1547 are located near the perimeter 1510 to provide perimeter weighting to increase the moment of inertia of the putter-type club head 1500. Furthermore, the weight of the toe and heel masses 1545, 1547 can be tailored to achieve a desired swing weight or overall putter head mass. The toe and heel masses 1545, 1547 comprise a mass top surface 1541 that forms a portion of the crown 1536. The upper portion 1504 and the lower portion 1508 each form a portion of the crown 1536 and the sole 1568. The lower portion 1508 further comprises a lower portion bottom surface 1542 that forms a portion of the sole. The toe and heel masses 1545, 1547 further comprise an inner surface 1561 located near the toe and heel walls 1529, 1530, and an outer surface 1543 that forms a portion of the perimeter 1510. In some embodiments, the outer surface 1543 forms a portion of the toe end 1512, the heel end 1516, or the rear end 1534. The inner surface 1561 defines a transition between the toe mass 1545 and the central portion 1538, as well as a transition between the heel mass 1547 and the central portion 1538. The inner surface 1561 comprises a corresponding geometry to the toe and heel walls 1529, 1530. The lower portion 1508 is configured to receive the upper portion 1504 such that the rearward extension 1524 is situated above the central portion 1538 and between the toe and heel masses 1545, 1547.

[0082] In some embodiments, the toe and heel masses 1545, 1547 form a tight fit with the upper portion 1504. In other embodiments, the inner surface 1561 and toe and heel walls 1529, 1530 define a gap 1595, 1597 therebetween. The gap 1595, 1597 allows toe and heel masses 1545, 1547 of varying sizes to be held within the cutout regions to tailor the weighting of the putter-type club head 1500. The gap 1595, 1597 defines a width measured between the respective inner surface 1561 and toe and heel walls 1529, 1530. The gap width can remain constant throughout the entire gap 1595, 1597, or the gap width can vary throughout the gap 1595, 1597. The gap width can be between 1.27mm to 5.334mm (0.05 inch to 0.21 inch). In some embodiments, the gap width is between 1.27mm to 2.286mm (0.05 inch to 0.09 inch), 1.778mm to 3.302mm (0.07 inch to 0.13 inch), 2.54mm to 4.572mm (0.10 inch to 0.18 inch), and 3.81mm to 5.334cm (0.15 inch to 0.21 inch). In some embodiments, the gap width is 1.27 mm, 1.524 mm,1.778 mm, 2.032 mm, 2.286 mm, 2.54 mm, 2.794 mm, 3.048 mm, 3.302 mm, 3.556 mm, 3.81 mm, 4.064 mm, 4.318 mm, 4.572 mm, 4.826 mm, 5.08 mm, or 5.334 mm (0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, 0.15 inch, 0.16 inch, 0.17 inch, 0.18 inch, 0.19 inch, 0.20 inch, or 0.21 inch). In one embodiment, the gap width is 4.064mm (0.16 inch). The gap width depends on the size and shaping of the toe and heel masses 1545, 1547 and the corresponding cutout regions.

[0083] The toe and heel masses 1545, 1547 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape. The geometry of the toe and heel masses 1545, 1547 corresponds to the geometry of the respective cutout region of the upper portion 1504.

[0084] The toe and heel masses 1545, 1547 provide an additional means of adding mass to the perimeter 1510 for increasing the MOI of the putter-type club head 1500 over a putter without these mass features. The lower portion 1508 comprises a mass between 200 grams to 215 grams. In some embodiments, the mass is between 200 grams to 210 grams, 205 grams to 210 grams, and 210 grams to 215 grams. The mass can be 200 grams, 201 grams, 202 grams, 203 grams, 204 grams, 205 grams, 206 grams, 207 grams, 208 grams, 209 grams, 210 grams, 211 grams, 212 grams, 213 grams, 214 grams, or 215 grams. In one embodiment, the mass is 205.7 grams.

[0085] The lower portion, and the toe and heel masses 1545, 1547 specifically, provide areas of concentrated mass near the perimeter 1510, such that toe and heel masses 1545, 1547 function to increase the moment of inertia of the putter-type club head 1500. The placement of the toe and heel masses 1545, 1547 on the perimeter 1510 increases the MOI since each mass is farther from a center of gravity of the putter-type club head 1500. The upper portion 1504 is affixed to the lower portion 1508, which is formed using the second material, wherein the second material is denser than the first material. The upper portion 1504 can be affixed to the lower portion 1508 with the use of an adhesive.

[0086] The lower portion 1508, in many embodiments, comprise less than 35% of a total volume of the putter-type club head 1500. In some embodiments, the lower portion 1508 comprises less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, or less than 23% of the total volume. In one embodiment, the lower portion 1508 comprises 30.1% of the total volume.

[0087] Although the lower portion 1508 comprises less than half of the volume of the putter-type club head 1500, the lower portion 1508 comprises at least 50% of a total mass of the putter-type club head 1500. In some embodiments, the lower portion 1508 comprises at least 51%, at least 52%, at least 53%, at least 54%, at least 55%, at least 56%, at least 57%, at least 58%, at least 59%, or at least 60% of the total mass. In one embodiment, the lower portion 1508 comprises 56.1% of the total mass. As discussed in more detail below, the lower portion 1508 comprises a low proportion (less than 50%) of the volume of the putter-type club head 1500 and a high proportion (greater than 50%) of the mass of the putter-type club head 1500.

[0088] The combination of the low-density upper portion 1504 with the high-density lower portion 1508, creates a high MOI putter-type club head 1500, without creating an extremely heavy putter. The central recess 1570 shifts a majority of the volume and mass of the putter-type club head 1500 to the perimeter 1510. This shift forms a low volume portion that increases MOI in comparison to a putter milled from a single material. A single material putter-type club head fails to allocate high-density material to the periphery, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams). The advantages of putter head 1500 over a putter head formed from a single material construction are described in the examples below.IV. Putter Head with Ball-Outlining Alignment Aid and Separate Weights

[0089] In one embodiment, the putter-type club head can comprise a two-part construction and can include an alignment aid having a ball-outlining feature. The two-part construction allows the putter-type club head to be formed from multiple materials. Referring to FIGS. 16A and 16B, the putter-type club head 1600 comprises a body 1604, a toe weight 1645, and a heel weight 1647. In some embodiments, the body 1604 is formed from a first material having a first density, and the toe and heel weights 1645, 1647 are formed from a second material having a second density. In some embodiments, the first density is less than the second density. As discussed in more detail below, the body 1604 and the toe and heel weights 1645, 1647 combine to create a high-MOI putter-type club head 1600 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass. For example, the putter head 1600 can have an MOI ranging from 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , 6000 g·cm 2< - 6500 g·cm 2< . The putter head 1600 comprises a 2%-15% increase of MOI about the y-axis over a putter head devoid of a multi-material construction (i.e. a single material). For example, the putter head 1600 comprises a 2%-5%, 5%-10%, or 10%-15% increase over a single material putter.

[0090] The putter-type club head 1600 further comprises a crown 1636, a sole 1668, a strike face 1620, a rear end 1634, a toe end 1612, and a heel end 1616. The outermost points of the strike face 1620, the rear end 1634, the toe end 1612, and the heel end 1616 define a perimeter 1610 of the putter-type club head 1600. The body 1604 and the toe and heel weights 1645, 1647 each form a portion of the crown 1636, a portion of the sole 1668, a portion of the toe end 1612, a portion of the heel end 1616, and a portion of the perimeter 1610. The crown 1636 gradually slopes from the strike face 1620 to the rear end 1634 such that the putter-type club head 1600 is thicker near the strike face 1620 and gradually thins towards the rear end 1634. The slope of the crown 1636 can be linear, curvilinear, parabolic, sinusoidal, or a function of polynomial. Further, the strike face 1620 comprises a strike face center point equidistant from the heel end 1616 and toe end 1612, as well as equidistant from the crown 1636 and the sole 1668.

[0091] In many embodiments, the sole 1668 can be planar. In some embodiments, the sole 1668 can have a slight arch in a heel 1616 to toe 1612 direction, wherein the slight arch can be linear, or a function of a polynomial. In some embodiments, the sole 1668 can have a strong arch in the heel 1616 to toe 1612 direction, wherein the strong arch can be linear, or a function of a polynomial. The sole 1568 functions to provide a surface to rest the putter-type club head 1600 on the ground plane. As discussed above, the putter-type club head 1600 comprises a body 1604, a toe weight 1645, and a heel weight 1647, where the body 1604 forms a majority of the sole 1668 and rests on the ground plane. The toe weight 1645 and heel weight 1647 sit above the body 1604 when the putter-type club head 1600 is assembled.

[0092] As discussed above, the body 1604 comprises a low-density material (i.e., the first material). In many embodiments, the body 1604 is formed from aluminum. The toe weight 1645 and the heel weight 1647 are affixed to the body 1604 to define the crown 1636, the sole 1668, the toe end 1612, the heel end 1616, and the perimeter 1610. The body 1604 comprises an upper surface 1626 and a lower surface 1628, where the upper surface 1626 forms a portion of the crown 1636, and the lower surface 1628 forms a portion of the sole 1668. The body 1604 further comprises a forward portion 1622 and a rear portion 1623, where the forward portion 1622 comprises the strike face 1620. The rear portion 1623 comprises a rearward extension 1624 that extends rearward from the forward portion 1622 towards the rear end 1634. The rearward extension 1624 is generally perpendicular to the strike face 1620. The forward portion 1622 and the rearward extension 1624 form a T-shape.

[0093] The body 1604 defines a central recess 1670 that extends from the forward portion 1622 to the rear end 1634. The central recess 1670 removes mass from a central portion of the body 1604, thereby allowing mass to be moved toward the perimeter 1610. The central recess 1670 is defined by a recess wall 1672 and a recess floor 1674. The recess floor 1674 is recessed into the body 1604 away from the body upper surface 1626, and the recess wall 1672 circumscribes the recess floor 1674.

[0094] The recess wall 1672 comprises a height. In some embodiments, the recess wall height slopes with the slope of the crown 1636 such that the recess wall height is larger near the strike face 1620 and smaller near the rear end 1634. In such an embodiment, the recess wall 1672 comprises a height near the rear end 1634 such that the recess floor 1674 is not flush with the body upper surface 1626. In other embodiments, the recess wall height remains constant throughout the central recess 1670. The recess floor 1674 is parallel to the ground plane to provide a parallel surface to the ground plane for portions of the alignment aid 1644. The central recess 6570 is located near a middle of the putter-type club head 1600 within the forward portion 1622 and the rear extension 1624 to provide a centered feature for the alignment aid 1644. The central recess 1670 further contributes to the alignment aid 1644, as discussed in more detail below.

[0095] The body 1604 further comprises an alignment aid 1644. The alignment aid 1644 is similar to the alignment aid 1544 and is described using similar reference numbers to the alignment aid 1544. For example, the alignment aid comprises one or more arcuate portions 1682 and a set of parallel lines 1684, which are similar to the one or more arcuate portions 1582 and the set of parallel lines 1584 of the alignment aid 1544. However, the alignment aid 1544 is located on the body upper surface 1626, instead of the upper portion top surface 1526, like the alignment aid 1544.

[0096] The alignment aid 1644 comprises a ball-outlining feature 1680, a central line 1676, and a plurality of grooves 1678. The ball-outlining feature 1680 can be similar to the ball-outlining feature 1580 shown in FIGS. 15D-15E. For example, the ball-outlining feature 1680 can partially or fully circumscribe the central recess 1670. In some embodiments, the parallel lines 1684 connect multiple arcuate portions 1682 to form a circular or oblong ball-outlining feature 1680 that fully circumscribes the central recess 1670, as shown in FIG. 15D. In other embodiments having only one arcuate portion 1682, the parallel lines 1684 extend rearward, thereby defining a U-shaped ball-outlining feature 1680 that partially circumscribes the central recess 1670. In some embodiments, the parallel lines 1684 extend fully to the rear end 1634, as shown in FIG. 15E. In other embodiments, the parallel lines 1684 extend partially to the rear end 1634, as shown in FIG. 15F. The ball-outlining feature 1680 generally follows the perimeter of the central recess 1670 and is located on the body upper surface 1626.

[0097] Further, the central line 1676 and the plurality of grooves 1678 can be similar to the central line 1576 and the plurality of grooves 1578 of the alignment aid 1544. The central line 1676 and the plurality of grooves 1678 are located on the recess floor 1674. The central line 1676 is positioned behind the strike face center point and extends through the entire length of the central recess 1670. The plurality of grooves 1678 that are recessed into the recess floor 1674 on either side of the central line 1676. Each feature of the alignment aid 1644 assists the viewer in aligning the putter-type club head 1600 with the golf ball. The alignment aid 1644 also utilizes the central recess 1670. The central recess 1670 provides a structure for the ball-outlining feature 1670 to outline. Further, the central recess 1670 houses the central line 1676 and the plurality of grooves 1678. As discussed above, the alignment aid 1644 is located near the body upper surface 1526 and extends from the forward portion 1622 through the rear extension 1623 to the rear end 1634. The rear portion 1623 is further configured to receive one or more weights.

[0098] The rear portion 1623 further comprises a toe wing 1629 and a heel wing 1630 that receive the toe weight 1645 and the heel weight 1647. The wings 1629, 1630 are located near the perimeter 1610 towards the rear end 1634 such that the rear extension 1624 extends between the wings 1629, 1630. The wings 1629, 1630 are defined between a wing floor 1632 and the sole 1668. The wing floor 1632 is recessed into the body 1604 away from the body upper surface 1626. The wing floor 1632 form a base for the wings 1629, 1630 to receive the weights 1645, 1647.

[0099] The rear portion defines a toe weight recess 1638 and a heel weight recess 1639. The weight recesses 1638, 1369 are located above the wings 1629, 1630 and function to receive the weights 1645, 1647. The weight recesses 1638, 1639 are defined a wing wall 1631 and the wing floor 1632, where the wing wall 1631 is adjacent to a respective recess floor 1632. The toe weight recess 1638 extends inwards from the toe end 1612 toward the center of the body 1604. The heel weight recess 1639 extends from the heel end 1616 toward the center of the body 1604. The weight recesses 1638, 1639 are bounded by the crown 1636, the perimeter 1610, the recess floor 1632, and the wing wall 1631.

[0100] The wing wall 1631 defines a boundary between the wings 1629, 1630 and the forward portion 1622, as well as a boundary between the wings 1629, 1630 and the rearward extension 1624. In some embodiments, the wing walls 1631 can fully encompass the weights 1645, 1647. In other embodiments, the wing walls 1631 can partially encompass the weights 1645, 1647. For example, in some embodiments, the wing wall 1631 can encompass between 30% to 45%, 40% to 65%, 50% to 90%, or 60% to 95% of the weight 1645, 1647.

[0101] The wings recesses 1638, 1369 are configured to receive the weights 1645, 1647 such that the weights 1645, 1647 sit above the wings 1629, 1630. Referring to FIG. 16B, the wings 1629, 1630 comprise an attachment point 1633 that receives a respective weight 1645, 1647. Each attachment point 1633 protrudes from the wing floor 1632 into the respective weight recess 1638, 1639. The attachment point 1633 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape.

[0102] The weight recesses 1638, 1369 and the wings 1629, 1630 can comprise any desired geometry. However, in many embodiments, the weight recesses 1638, 1369 and the wings 1629, 1630 comprise a geometry similar or identical to that of the weight 1645, 1647. Each weight recess 1638, 1369 corresponds to a respective wing 1629, 1630 and attachment point 1633 for a respective weight 1645, 1647.

[0103] Referring to FIG. 16A, the putter-type club head 1600 comprises a heel weight 1647 and a toe weight 1645 that correspond to a respective wing 1629, 1630, weight recess 1638, 1639, and attachment point 1633. However, the putter-type club head 1600 is not limited to a heel weight 1647 and a toe weight 1645. In some embodiments, the putter-type club head 1600 can comprise one, two, three, four, five, six, seven, or eight weights. In these embodiments, the putter-type club head 1600 can comprise one, two, three, four, five, six, seven, or eight corresponding wings and attachment points.

[0104] The weights 1645, 1647 comprise a high-density material (i.e., the second material) than the body 1604. In many embodiments, the weights 1645, 1647 are formed from stainless steel. The weights 1645, 1647 are located near the perimeter 1610 and are affixed to the body 1604. Referring to FIGS. 16B and 16D, the weights 1645, 1647 comprise an inner surface 1661 located near the wing wall 1631, and an outer surface 1643 that forms a portion of the perimeter 1610. In some embodiments, the outer surface 1643 forms a portion of the toe end 1612, the heel end 1616, or the rear end 1634. The inner surface 1661 comprises a corresponding geometry to the wing wall 1631.

[0105] In some embodiments, the weights 1645, 1647 form a tight fit with the body 1604. In other embodiments, the inner surface 1661 and the wing wall 1631 define a gap 1695, 1697 therebetween. The gap 1695, 1697 allows weights 1629, 1630 of varying sizes to be held within the weight recesses 1638, 1639 to tailor the weighting of the putter-type club head 1600. The gap 1695, 1697 defines a width measured between the respective inner surface 1661 and wing wall 1631. The gap width can remain constant throughout the entire gap 1695,1697, or the gap width can vary throughout the gap 1695, 1697. The gap width can be between 1.27mm to 5.334mm (0.05 inch to 0.21 inch). In some embodiments, the gap width is between 1.27mm to 2.286mm (0.05 inch to 0.09 inch), 1.778mm to 3.302mm (0.07 inch to 0.13 inch), 2.54mm to 4.572mm (0.10 inch to 0.18 inch), and 3.81mm to 5.334mm (0.15 inch to 0.21 inch). In some embodiments, the gap width is 1.27 mm, 1.524 mm,1.778 mm, 2.032 mm, 2.286 mm, 2.54 mm, 2.794 mm, 3.048 mm, 3.302 mm, 3.556 mm, 3.81 mm, 4.064 mm, 4.318 mm, 4.572 mm, 4.826 mm, 5.08 mm, or 5.334 mm (0.05 inch, 0.06 inch, 0.07 inch, 0.08 inch, 0.09 inch, 0.10 inch, 0.11 inch, 0.12 inch, 0.13 inch, 0.14 inch, 0.15 inch, 0.16 inch, 0.17 inch, 0.18 inch, 0.19 inch, 0.20 inch, or 0.21 inch). In one embodiment, the gap width is 4.064mm (0.16 inch).

[0106] The weights 1645, 1647 further comprise a weight upper surface 1640 and a weight lower surface 1642. The weight upper surfaces 1640 form a portion of the crown 1636, and the weight lower surfaces 1642 form a portion of the sole 1668. The weight lower surfaces 1642 are proximate the wing floors 1632 and comprise a corresponding geometry to the respective wings 1629, 1630 and attachment points 1633. Referring to FIG. 16D, the weight lower surface 1642 comprises a stepped-down geometry that corresponds to the respective wing 1629, 1630 and attachment point 1633 geometry. The weights 1645, 1647 slide over the attachment point 1633 and are further secured with an epoxy material. In some embodiments, the wing floors 1632 comprise a plurality of grooves that increase the surface area of the wing floor 1632. The plurality of grooves increase the surface area available for bonding, thereby strengthening the bond between the weights 1645, 1647 and the floor 1632. The geometry of the weight lower surface 1642 facilitates a tight connection between the weights 1645, 1647 and the wings 1629, 1630.

[0107] The weights 1645, 1647 can respectively be any one or combination of the following shapes: rectangular, triangular, pyramidal, spherical, semi-circular, square, cylindrical, ovular, elliptical, trapezoidal, pentagonal, hexagonal, octagonal, or any other desired geometric or non-geometric shape. The geometry of the weights 1645, 1647 corresponds to the geometry of the respective weight recess 1638,1639.

[0108] The weights 1645, 1647 provide an additional means of adding mass to the perimeter 1610 for increasing the MOI of the putter-type club head 1600 over a putter without these mass features. Furthermore, the weights 1645, 1647 can be tailored to achieve a desired swing weight or overall putter head mass. The weights 1645, 1647 comprise a combined mass between 45 grams to 70 grams. In some embodiments, the mass is between 45 grams to 60 grams, 55 grams to 70 grams, and 55 grams to 65 grams. The combined mass can be 45 grams, 46 grams, 47 grams, 48 grams, 49 grams, 50 grams, 51 grams, 52 grams, 53 grams, 54 grams, 55 grams, 56 grams, 57 grams, 58 grams, 59 grams, 60 grams, 61 grams, 62 grams, 63 grams, 64 grams, 65 grams, 66 grams, 67 grams, 68 grams, 69 grams, or 70 grams. The weights 1645, 1647 provide areas of concentrated mass near the perimeter 1610, such that each weight 1645, 1647 functions to increase the moment of inertia of the putter-type club head 1600. The placement of each weight 1645, 1647 on the perimeter 1610 increases the MOI since each mass is farther from a center of gravity of the putter-type club head 1600. Each weight 1645, 1647 is affixed to the body 1604 using the second material, wherein the second material is denser than the first material.

[0109] The weights 1645, 1647, in many embodiments, comprise less than 25% of a total volume of the putter-type club head 1600. In some embodiments, the weights 1645, 1647 comprise less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, or less than 13% of the total volume.

[0110] Although the weights 1645, 1647 comprise less than half of the volume of the putter-type club head 1600, the weights 1645, 1647 comprise at least 30% of a total mass of the putter-type club head 1600. In some embodiments, the weights 1645, 1647 comprise at least 31%, at least 32%, at least 33%, at least 34%, at least 35%, at least 36%, at least 37%, at least 38%, at least 39%, or at least 40% of the total mass.

[0111] The combination of the low-density body 1604 with the high-density weights 1645, 1647, creates a high MOI putter-type club head 1600, without creating an extremely heavy putter. The central recess 1670 shifts a majority of the volume and mass of the putter-type club head 1600 to the extremities of the body 1604. This shift forms a low volume portion that increases MOI in comparison to a putter milled from a single material. A single material putter-type club head fails to allocate high-density material to the periphery, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams).V. Three-Part Putter Head

[0112] In Figure 18 which is shown for explanation only to aid an understanding of the invention and, rather than a two part putter, the putter type golf club head can comprise a three part construction including a crown portion 1802 in addition to the upper portion and the lower portion. Providing a three-part putter head comprising a crown portion 1802 in addition to the upper portion and the lower portion allows the mass distribution throughout the putter head to be more precisely controlled and optimized to increase the MOI of the putter head.

[0113] The upper portion of the three-part putter-type golf club head can be similar to one or more of the upper portions described in reference to previous embodiments and can be made of the first material described above. Similarly, the lower portion of the three-part putter-type golf club head can be similar to one or more of the lower portions described in reference to previous embodiments and can be made of the second material described above.

[0114] The three-part putter head further comprises a crown portion made of a third material different than both the first material of the upper portion and the second material of the lower portion. The third material can be lightweight and can comprise a density less than both the first density and the second density. In many embodiments, the crown portion 1802 can be joined to the top of the upper portion and can form the uppermost surface of the putter head.

[0115] In many embodiments, the crown portion of the putter head having the third material comprises a third density ranging between 0.5 g / cc and 3.5 g / cc. The third density can range between 1.5 g / cc to 2.5 g / cc. In some embodiments, the third density can range between 0.5 - 0.75 g / cc, 0.75 - 1.0 g / cc, 1.0 - 1.25 g / cc, 1.25 - 1.5 g / cc, 1.5 - 1.75 g / cc, 1.75 - 2.0 g / cc, 2.0 - 2.25 g / cc, 2.25 - 2.5 g / cc, 2.5 - 2.75 g / cc, 2.75 - 3.0 g / cc, or 3.25 - 3.5 g / cc. In one embodiment, the third density of the crown portion 1802 can range between 1.0 - 2.0 g / cc. In some embodiments, the third density can be less 3.5 g / cc, less than 3.0 g / cc, less than 2.5 g / cc, less than 2.0 g / cc, less than 1.5 g / cc, or less than 1.0 g / cc. In some embodiments, the third density can be 0.5 g / cc, 0.75 g / cc, 1.0 g / cc, 1.25 g / cc, 1.50 g / cc, 1.75 g / cc, 2.0 g / cc, 2.25 g / cc, 2.50 g / cc, 2.75 g / cc, 3.0 g / cc, 3.25 g / cc, or 3.50 g / c.

[0116] The crown portion of the putter head having the third material can be made from any one or combination of the following: aluminum, aluminum alloy, ADC-12, a polymeric material, a composite material, a filled thermoplastic, a fiber-reinforced composite, or any other suitable low-density material.

[0117] Inclusion of the low-density crown portion allows for an increase in the MOI of the putter head. Replacing portions of the club head that would otherwise be made of either the first material or the second material creates discretionary mass that can be reallocated throughout the putter head.a. Three-Part Spade Shaped Embodiment

[0118] FIGS. 18A-18D illustrate for explanation only and to aid an understanding of the invention, a first embodiment of the three-part putter-type golf club head 1800. Putter head 1800 is a spade shaped putter head 1800, similar to the two-part spade shaped putter head 700 of FIGS. 7A-7C. The three-part spade shaped putter head 1800 comprises an upper portion 1804, a lower portion 1808, and a crown portion 1802, and a hollow interior cavity 1850 formed between the upper portion 1804, lower portion 1808, and crown portion 1802. The upper portion 1804 is made from a first material having a first density, the lower portion 1808 is made from a second material having a second density, and the crown portion 1802 is made from a third material having a third density. The first density is less than the second density. The third density is less than both the first density and the second density. The upper portion 1804, lower portion 1808, and crown portion 1802 combine to create a high-MOI putter head (3500 g·cm 2< - 5000 g·cm 2< ) 1800 while maintaining a desirable volume and mass. For example, in some embodiments, the putter head 1800 can comprise an MOI approximately between 3500 g·cm 2< and 4000 g·cm 2< , between 4000 g·cm 2< and 4500 g·cm 2< , or between 4500 g·cm 2< and 5000 g·cm 2< . In some embodiments, the putter head 1800 can comprise an MOI approximately between 3500 g·cm 2< and 3750 g·cm 2< , between 3750 g·cm 2< and 4000 g·cm 2< , between 4000 g·cm 2< and 4250 g·cm 2< , between 4250 g·cm 2< and 4500 g·cm 2< , between 4500 g·cm 2< and 4750 g·cm 2< , or between 4750 g·cm 2< and 5000 g·cm 2< .

[0119] As illustrated in FIG. 18A, the upper portion 1804 forms a majority of the main body of the putter head 1800. The upper portion 1804 comprises a base 1830 and a plurality of walls extending vertically from the base 1830. The upper portion 1804 can comprise a plurality of perimeter walls including a front wall 1812 defining a strike face 1820, a toe wall 1814, a heel wall 1816, and a rear wall 1832. The front wall 1812 is adjacent to the toe wall 1814 and the heel wall 1816, and opposite to the rear wall 1832. An exterior surface of the front wall 1812 forms the strike face 1820 while an interior surface of the front wall 1812 forms a back face 1824. The toe wall 1814 is adjacent to the front wall 1812 and the rear wall 1832, and opposite to the heel wall 1816. The heel wall 1816 is also adjacent to the front wall 1812 and the rear wall 1832, but opposite to the toe wall 1814.

[0120] The plurality of perimeter walls can form the majority of a perimeter of the putter head 1800. The base 1830 can extend from the front wall 1812 to the rear wall 1832 and from the toe wall 1814 to the heel wall 1816. The base 1830 further comprises an upper surface 1831 and a lower surface 1833 opposite the upper surface 1831. The lower surface 1833 of the base 1830 forms at least a portion of the sole 1868. In many embodiments, referring to FIG. 18C, the lower surface 1833 can comprise a recessed area 1840 configured to receive the lower portion 1808 such that the lower surface 1833 of the base 1830 forms part of the sole 1868 and a bottom surface 1882 of the lower portion 1808 forms the remainder of the sole 1868.

[0121] The upper portion 1804 further comprises a plurality of internal walls 1838 extending vertically from the base 1830. Each of the plurality of internal walls 1838 are inset with respect to the perimeter of the putter head 1800. The plurality of internal walls 1838 therefore do not form any portion of the club head perimeter. As illustrated in FIG. 18A, the plurality of perimeter walls and the plurality of internal walls 1838 can be interconnected. The interconnection between the plurality of perimeter walls and the plurality of internal walls 1838 can collectively form a cavity profile, when viewed from above, wherein the cavity profile defines the shape of the hollow interior cavity 1850. The shape of the cavity profile is defined by the orientation and shaping of the plurality of perimeter walls and the plurality of internal walls 1838. In some embodiments, such as the embodiment illustrated in FIG. 18A, the upper portion 1804 can comprise one or more internal walls 1838 extending substantially perpendicular to the strike face 1820 and one or more internal walls 1838 extending substantially parallel to the strike face 1820. In other embodiments, one or more internal walls 1838 can extend at an angle with respect to the strike face 1820. FIG. 18A illustrates the plurality of internal walls 1838 being formed as substantially straight walls, but in other embodiments, the putter head 1800 can comprise one or more internal walls 1838 that are curved. The top of the upper portion 1804 can be open such that the upper portion 1804 by itself does not enclose any hollow portions or interior cavities.

[0122] The upper portion 1804 can further define one or more external portions 1835 situated outside of the cavity profile. The one or more external portions 1835 form areas of the putter head 1800 wherein the upper surface 1831 of the base 1830 is exposed to the exterior of the putter head 1800. The one or more external portions 1835 can be partially bounded by the exterior surface of one or more internal walls 1838, but the external portions 1835 are not bounded on any sides by any of the plurality of perimeter walls.

[0123] The upper portion 1804 further comprises a central aperture 1864 extending through a portion of the base 1830. The central aperture 1864 extends through both the upper surface 1831 and the lower surface 1833 of the base 1830. The central aperture 1864 shifts a large portion of the volume and mass of the putter head 1800 to the extremities of the upper portion 1804. The central aperture 1864 can be configured to be covered by the lower portion 1808 to enclose the hollow interior cavity 1850.

[0124] As illustrated by FIGS. 18A and 18B, the crown portion 1802 forms the majority of the top surface of the putter head 1800. The crown portion 1802 can comprise a thin, cover-like structure configured to overlay the upper portion 1804. The plurality of walls can provide surfaces 1834 to which the crown portion 1802 is attached. As illustrated in FIG. 18A, the shape of the crown portion 1802 is complementary to the geometry of the upper portion 1804. In particular, the shape of the crown corresponds to the cavity profile formed by the plurality of upper portion walls. The perimeter edges of the crown portion 1802 can be configured to attach to the top surfaces 1834 of the upper portion perimeter walls and the upper portion internal walls 1838. As illustrated in FIG. 18B, by overlaying the top of the lower portion 1808, the crown portion 1802 entirely encloses the top of the hollow interior cavity 1850.

[0125] The crown portion 1802 comprises a front edge 1870 extending along the front wall 1812 in a heel-to-toe direction. The front edge 1870 can extend all the way from the toe wall 1814 to the heel wall 1816. The crown portion 1802 further comprises a central extension 1842, a heel extension 1846, and a toe extension 1848. The central extension 1842 extends rearward from the front edge 1870, near the center of the front wall 1812. The central extension 1842 extends all the way from the front wall 1812 to the rear wall 1832 and covers a central area of the cavity profile. The heel extension 1846 extends rearward from a heel side of the front edge 1870. The heel extension 1846 extends along the heel wall 1816 and extends a portion of the way from the front wall 1812 to the rear wall 1832. The toe extension 1848 extends rearward from a toe side of the front edge 1870. The toe extension 1848 extends along the toe wall 1814 and extends a portion of the way from the front wall 1812 to the rear wall 1832.

[0126] Furthermore, the crown portion 1802 of the putter head 1800 can comprise one or more alignment features 1836. The alignment feature 1836 can be any one or combination of the following: a line, a series of lines, milling troughs, a circle, a dashed line, a triangle, a channel, or any other desired alignment feature 1836. In the embodiment of FIGS. 18A-18D, the central extension 1842 is configured to be the width of a golf ball (approximately 4.27 cm). The alignment features 1836, extending along the crown portion 1802, function to provide the viewer a visual alignment field that extends the width of the golf ball, from the strike face 1820 to the rear of the putter head 1800. The goal is to align the entire putter head 1800 with the golf ball using these alignment features 1836 along the crown portion 1802.

[0127] As illustrated by FIG. 18D, the lower portion 1808 can form a majority of the sole 1868. The lower portion 1808 can be formed as a substantially flat, high-density sole plate. In many embodiments, the lower portion 1808 is received within the recessed area 1840 of the upper portion lower surface 1833. The lower portion 1808 can be received within the upper portion 1804 such that a bottom surface 1882 of the lower portion 1808 sits flush with the lower surface 1833 of the upper portion 1804. In this way, the bottom surfaces 1833, 1882 of the upper portion 1804 and lower portion 1808 combine to define a generally continuous sole surface at the bottom of the putter head 1800. In some embodiments, referring to FIG. 18A, the top surface 1880 of the lower portion 1808 can comprise one or more recesses 1886. The one or more recesses 1886 can be located near the center of the lower portion 1808. The one or more recesses 1886 can serve to shift mass toward the perimeter of the lower portion 1808.

[0128] Referring to FIG. 18D, the lower portion 1808 is located toward the rear wall 1832 of the putter head 1800 and can extend substantially between the heel wall 1816 and the toe wall 1814. As such, the majority of the sole 1868 proximate the rear wall 1832 is formed by the lower portion bottom surface 1882. In many embodiments, the lower portion 1808 can be spaced rearwardly from the front wall 1812. As such, the majority of the sole 1868 proximate the strike face 1820 can be formed by the lower surface 1833 of the upper portion 1804.

[0129] The lower portion 1808 is configured to be received such that it covers the upper portion aperture 1864 from the bottom of the putter head 1800. The lower portion 1808 can seal off the hollow interior cavity 1850 from the sole 1868, enclosing the bottom of the hollow interior cavity 1850.

[0130] When joined together, the upper portion 1804, the lower portion 1808, and the crown portion 1802 form a hollow interior cavity 1850 within the putter head 1800. The hollow interior cavity 1850 is bounded between interior surfaces of the perimeter walls and internal walls 1838 of the upper portion 1804, an underneath surface (not shown) of the crown portion 1802, and the top surface 1880 of the lower portion 1808. The hollow interior cavity 1850 removes a large amount of mass from near the center of gravity. The hollow interior cavity 1850 thereby increases the MOI of the putter head 1800 by allowing mass to be shifted toward perimeter of the putter head 1800.

[0131] In FIGS. 18A-18D, the hollow interior cavity 1850 is completely enclosed by the upper portion 1804, lower portion 1808, and crown portion 1802 such that there are no openings from the exterior of the putter head 1800 into the hollow interior cavity 1850. Completely enclosing the interior cavity 1850 by the upper portion 1804, lower portion 1808, and crown portion 1802 provides the putter head 1800 with the high MOI of a hollow putter head while retaining the appearance of a solidly constructed putter head.

[0132] In some examples the hollow interior cavity 1850 can comprise a filler material (not shown). In some embodiments, the filler material can completely fill the volume of the hollow interior cavity 1850. In other embodiments, the filler material can fill only a portion of the volume of the hollow interior cavity 1850. In some embodiments the filler material can fill greater than 5%, greater than 10%, greater than 20%, greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90% of the volume of the hollow interior cavity 1850. In other embodiments, the filler material can fill less than 90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than 10%, or less than 5% of the volume of the hollow interior cavity 1850.

[0133] The filler material can be a polymer. The polymer can comprise a thermoplastic, a thermoplastic elastomer, polyurethane, ethylene, vinyl acetate, ethylene vinyl acetate (EVA), polyolefin copolymer, styrene, styrene-butadiene, a polymer foam material, any other suitable polymer material, or any combination thereof. In other embodiments, the filler material can comprise an elastomer, a polyurethane elastomer, a silicone, a silicone elastomer, a rubber, or a vulcanized natural rubber latex. In other embodiments still, the filler material can be an epoxy, a resin, an adhesive, a polyurethane adhesive, a glue, or any other suitable adhesive. For example, the carrier can be a polyurethane adhesive such as Gorilla Glue (Gorilla Glue Company, Cincinnati Ohio). In another example, the filler material can be a polyurethane elastomer such as Freeman 1040 (Freeman Manufacturing & Supply Company, Avon Ohio), or a polyurethane based thermoplastic elastomer such as Freeman 3040 (Freeman Manufacturing & Supply Company, Avon Ohio). In some embodiments, the filler material can be a lattice material. The lattice filler material can be formed from a metal using processes such as casting, die casting, co die casting, additive manufacturing, or metallic 3D printing.

[0134] The combination of the low density first material upper portion 1804 and low density third material crown portion 1802 with the high density second material lower portion 1808, creates a high MOI putter head 1800, without creating an extremely heavy putter head 1800. Providing the hollow interior cavity 1850 allows for the inclusion of a dense, yet low volume lower portion 1808 that increases the MOI of the putter head 1800, in comparison to a putter head milled from a single material. A single material putter head fails to allocate high density material to the perimeter, while maintaining a desirable volume (75 cc - 100 cc) and mass (340 grams - 385 grams). In one example, the putter head 1800 comprises a high MOI, a desirable volume (91 cc), and a desirable mass (361 grams).

[0135] The lower portion 1808, in most embodiments, comprises less than 40% of a total volume of the putter head 1800. In some embodiments, the lower portion 1808 comprises less than 39% of the total volume of the putter head 1800, less than 38% of the total volume of the putter head 1800, less than 37% of the total volume of the putter head 1800, less than 36% of the total volume of the putter head 1800, less than 35% of the total volume of the putter head 1800, less than 34% of the total volume of the putter head 1800, less than 33% of the total volume of the putter head 1800, less than 32% of the total volume of the putter head 1800, less than 31% of the total volume of the putter head 1800, or less than 30% of the total volume of the putter head 1800.

[0136] The inclusion of the hollow interior cavity 1850 allows a large proportion of the mass of the putter head 1800 to be concentrated in the lower portion 1808 without creating an extremely heavy putter head 1800. Although the lower portion 1808 comprises less than 40% of the volume of the putter head 1800, the lower portion 1808 comprises at least 60% of an overall mass of the putter head 1800. In some embodiments, the lower portion 1808 comprises at least 61 % of the mass of the putter head 1800, at least 62% of the mass of the putter head 1800, at least 63% of the mass of the putter head 1800, at least 64% of the mass of the putter head 1800, at least 65% of the mass of the putter head 1800, at least 66% of the mass of the putter head 1800, at least 67% of the mass of the putter head 1800, at least 68% of the mass of the putter head 1800, at least 69% of the mass of the putter head 1800, or at least 70% of the mass of the putter head 1800.

[0137] The beneficial shift of mass to the perimeter of the putter head 1800, through the use of a high density, low volume lower portion 1808 and the inclusion of a hollow interior cavity 1850 increases the MOI of the putter head 1800. The putter head 1800 comprises an increased MOI over a putter head with the same volume, mass, and single material construction (i.e., a putter head milled of a single stainless steel block, or a putter head investment cast of a single material).VI. Benefits

[0138] The putter-type golf club head provides MOI, CG, feel, and weighting benefits, in a putter-type golf club head with an upper and lower portion having different densities and / or without using mechanically fastened weights or weight ports. By creating an upper portion and lower portion of a putter-type golf club head from two different material, the weighting of the club head shifts towards the peripheries of the putter-type golf club head, without any weight ports or attachments to the heel end and toe end of the putter-type golf club head. This shift in weight, towards the peripheries of the putter-type golf club head, raises the MOI of the club head about the y-axis (Iyy), therefore preventing the rotation about the y-axis and assuring the strike face is square to a golf ball during impact. The increase in MOI about the y-axis helps achieve a straighter ball path and improve the outcome of off-centered hits (impact at the heel end or toe end).

[0139] By creating the 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 desirable overall weight. In some embodiments, the moment of inertia of the golf club head about the y-axis center of gravity is between 3500 g·cm 2< - 6500 g·in 2< . In other embodiments the moment of inertia of the golf club head about the y-axis center of gravity can be between 3500 g·cm 2< - 4000 g·cm 2< , 4000 g·cm 2< - 4500 g·cm 2< , 4500 g·cm 2< - 5000 g·cm 2< , 5000 g·cm 2< - 5500 g·cm 2< , 5500 g·cm 2< - 6000 g·cm 2< , or 6000 g·cm 2< - 6500 g·cm 2< . The golf club head comprises a 2%-15% increase in MOI about the y-axis over a club head devoid of a multi-material construction (i.e. a single material). In other embodiments, the golf club head has a 2%-5%, 5%-10%, or 10%-15% increase over a club head with a single material.

[0140] The putter-type golf club head with 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 with the same volume, mass, and single material construction (i.e., a putter milled of a single material such as a steel putter or a putter investment cast of a single material). In some embodiments, the putter-type golf club head with upper and lower portions of two different materials, increases the MOI about the y-axis center of gravity by at least 35%, by at least 40%, by at least 45%, by at least 50%, by at least 55%, by at least 60%, by at least 65%, by at least 70%, by at least 75%, by at least 80%, by at least 85%, by at least 90%, by at least 95%, by at least 95%, by at least 100%, or by at least 105%, over a putter with the same volume, mass, and single material construction.

[0141] The putter-type golf club head with the alignment aid 1544 of FIGS. 15A-15D provides visual advantages that are pleasing to the eye and created repeatability in putting. The alignment aid 1544 assists the user in properly aligning the putter head with the golf ball on a consistent basis. The alignment aid 1544 comprises a ball outlining feature 1580 which helps the viewer align the putter head with the outsides of the golf ball and a central line 1576 that aligns the center of the golf ball with the putter head. The proper alignment of the putter head with the golf ball enables the user to start the ball on the intended line. The putter head including the alignment aid 1544 provides increased perimeter weighting, MOI, and forgiveness while being pleasing to the eye to create a consistent putting stroke.VII. EXAMPLES a. Example 1 -High MOI Putter Head

[0142] Example 1 putter head 1300 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The example 1putter head 1300 comprised an upper portion 1304 formed from a low-density material and a lower portion 1308 formed from a high-density material as illustrated in FIGS. 13A - 13E. The lower portion 1308 further comprised a sole plate including a toe mass 1345 and a heel mass 1347 to increase perimeter weighting. The upper portion 1300 further comprised a pocket 1372 to allow for mass removal from a center portion of the putter head 1300. The control putter head comprised a similar mass, volume, and weight to the exemplary putter head 1300, but comprised a single material construction.

[0143] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the Example 1putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the Example 1putter 1300 having a total mass of 363.2 grams and a total volume 85.2 cc. The lower portion 1308 comprised a sole plate mass of 207.4 grams and a sole plate volume of 26.55 cc. The lower portion 1308 comprised 57.1% of the total mass of putter 1300 while comprising 31.16% of the total volume of the putter 1300.

[0144] The Example 1putter 1300 comprised a MOI of 4368 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 3702 g·cm 2< about the y-axis (Iyy). The results show the Example 1putter head 1300 comprised a 10.78% increase in MOI over the control putter head. The Example 1putter head 1300 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The Example 1putter 1300 achieves a high MOI with a multi-material construction over a putter head formed from a single material.b. Example 2 -High MOI Putter Head

[0145] Example 2 putter head 1400 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The Example 2putter 1400 comprised an upper portion 1404 formed from a low-density material and a lower portion 1408 formed from a high-density material as illustrated in FIGS. 14A - 14D. The lower portion 1408 further comprised a sole plate including a toe mass 1446, a heel mass 1448, and a rear mass 1450 to increase perimeter weighting. The Example 2putter head 1400 further comprised a ball retrieval feature 1422 located on the sole 1442. The ball retrieval feature 1422 further increases perimeter weighting by removing material and mass from a central area of the putter head 1400. The control putter head comprised a similar mass, volume, and weight to the Example 2putter head 1300, but comprised a single material construction.

[0146] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the Example 2putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the Example 2 putter 1400 having a total mass of 360 grams and a total volume 80.79 cc. The lower portion 1408 comprised a sole plate mass of 228 grams and a sole plate volume of 29.74 cc. The lower portion 1408 comprised 63% of the total mass of putter 1400 while comprising 37% of the total volume of the putter 1400.

[0147] The Example 2 putter 1400 comprised an MOI of 4710 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 4474 g·cm 2< about the y-axis (Iyy). The test results show the Example 2 putter head 1400 comprised a 5.26% increase in MOI over the control putter head. The Example 2 putter head 1400 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The Example 2 putter 1400 achieves a high MOI with a multi-material construction over a putter head formed from a single material.c. Example 3 - Exemplary High MOI Putter Head

[0148] An exemplary putter head 1500 comprising a multi-material construction was compared to a similar control putter head, but devoid of a multi-material construction. The exemplary putter head 1500 comprised an upper portion 1504 formed from a low-density material and a lower portion 1508 formed from a high-density material as illustrated in FIGS. 15A - 15D. The lower portion 1508 comprised a sole plate including a toe mass 1545 and a heel mass 1547 to increase perimeter weighting. The upper portion 1504 further defines a central recess 1570 to allow for mass removal from a center portion of the putter-type club head 1500. The control putter head comprised a similar mass, volume, and weight to the exemplary putter head 1500, but comprised a single material construction.

[0149] A test was conducted to compare the moment of inertia about the y-axis (Iyy) between the exemplary putter head 1300 and the control putter head. The moment of inertia about the y-axis is the property that determines the forgiveness of the putter head (i.e., resists twisting motion after a golf ball impact). The test resulted in the exemplary putter-type club head 1500 having a total mass of 366.5 grams and a total volume of 87 cc. The lower portion 1508 comprised a sole plate mass of 205.7 grams and a sole plate volume of 26.2 cc. The lower portion 1508 comprised 56.1% of the total mass of putter-type club head 1500 while comprising 30.1% of the total volume of the putter-type club head 1500.

[0150] The exemplary putter-type club head 1500 comprised a MOI of 4416 g·cm 2< about the y-axis (Iyy). The control putter head comprised a MOI of 4324 g·cm 2< about the y-axis (Iyy). The test results show the exemplary putter head comprised a 2.12% increase in MOI over the control putter head. The exemplary putter head 1500 achieves desirable perimeter weighting to increase MOI and forgiveness while maintaining a desirable mass and volume. The exemplary putter head 1500 achieves a high MOI with a multi-material construction over a putter head formed from a single material. The exemplary putter head 1500 further comprised a ball outlining alignment aid to improve putt consistency while being pleasing to the eye during repeated ball impacts.d. Example 4 - Putter Alignment Aid Test

[0151] Further described herein is a player test comparing two putter-type club heads having different alignment aids. The club heads were mallet-style club heads having a similar shape but comprised different alignment aid styles. The results compared the effect of the different alignment aid types on player satisfaction and performance.

[0152] The first putter-type club head (hereafter referred to as the "control club head") comprised an alignment aid (hereafter referred to as the "control aid"), similar to club head 1200, as shown in FIG. 12A. The control aid was positioned on the crown and included three parallel lines that extended from the strike face to the rear end. The central line was positioned behind the strike face center point, and the remaining lines were positioned on the heel and toe sides of the central line. The three parallel lines were approximately the width of a golf ball [i.e. 4.267 cm (1.68 inches)]. The parallel lines comprised a color different from the color of the control club head. The control aid further comprised a plurality of grooves positioned between the parallel lines.

[0153] The second putter-type club head (hereafter referred to as the "exemplary club head") comprised an alignment aid (hereafter referred to as the "exemplary aid"), similar to the alignment aid 1544 associated with club head 1500, as shown in Fig. 15D. The exemplary club head defined a central recess that extended from the strike face to the rear end. The exemplary aid comprised a ball-outlining feature that outlined a perimeter of the central recess. The ball-outlining feature included two arcuate portions, where one arcuate portion arced near the strike face and the other arced near the rear end. The arcuate portions were connected by a set of parallel lines to form a continuous perimeter around the central recess. The ball-outlining feature was approximately the width of a golf ball and resembled an oblong golf ball shape due to the arcuate portions. The ball-outlining feature comprised a color different from the color of the exemplary club head. The exemplary aid further comprised a central line positioned within the central recess and extending along the length of the central recess. The central line was further positioned behind the strike face center point.

[0154] A player test was conducted to compare the alignment aid performance between the exemplary aid and the control aid. The player test involved thirty players who participated in a survey that compared their experiences with the exemplary aid having a ball-outlining feature, and the control aid devoid of a ball-outlining feature. The players tested each club head under similar conditions, where the putter club heads included similar shaft lengths and similar loft angles. Further, the player test was conducted on a typical putting surface. The test involved hitting a golf ball across the putting surface with the control putter head and the exemplary putter head.

[0155] After testing, the participants rated the club head performance and satisfaction based on five parameters. The parameters included the alignment aid look, the alignment aid performance, the overall club head feel, accuracy, and the comfort at address position. Based on these parameters, the club heads were given a rating of between 1 to 5. A rating of 1 represented the lowest level of satisfaction, where the club head only met 1 of the parameters. A rating of 5 represented the highest level of satisfaction, where the club head met all 5 of the parameters. A rating of 4 represented a high level of satisfaction, where the club head met 3 or more of the parameters. Control Exemplary Increase Number of Participants who Rated 4 or 5 (out of 30)132053.8%Percentage of Participants who Rated 4 or 546.4%68.9%48.5%

[0156] Table 1 above illustrates the number of participants who gave each sample club head a "good" rating, where a "good" rating was a score of 4 or 5. The exemplary club head was rated higher than the control club head. The control club head received a "good" rating from 46.4% of the players while the exemplary club head received a "good" rating from 68.9% of the players.

[0157] The test resulted in the exemplary aid meeting more of the parameters than the control aid (e.g., alignment aid look, alignment aid performance, the overall club head feel, accuracy, and comfort at the address position). The participants in the player test felt the exemplary putter head performed better than the control putter head. The exemplary aid provides advantages over the control aid. The exemplary aid included multiple components that each provided a function to the alignment aid. The ball-outlining feature defined an oblong shape that generally resembled a golf ball and helped the viewer outline the sides of the golf ball. The central line helped the viewer find the center of the club head. Further, the exemplary aid utilized the central recess, where the recess walls disappeared when the club head was in alignment. The exemplary putter head comprising the exemplary aid provided improved player performance and satisfaction while comprising a high MOI.

[0158] As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and / or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St. Andrews (R&A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and / or sold as conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.

[0159] The above examples may be described in connection with a putter-type golf club, the apparatus, methods, and articles of manufacture described herein. Alternatively, the apparatus, methods, and articles of manufacture described herein may be applicable other type of sports equipment such as a hockey stick, a tennis racket, a fishing pole, a ski pole, etc.

Examples

embodiment

h. Dual-Rail Embodiment

[0051]Referring to FIGS. 9A and 9B, a dual-rail putter head 900 is shown for explanation only to aid an understanding of the invention and has a upper portion 904 and a lower portion 908. The upper portion 904 is made from a first material have 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 lower portion 908 combine to create a high-MOI putter head 900 (5000 g·cm 2< - 6500 g·cm 2< ), while maintaining a desirable volume and mass.

i. Circular Embodiment

[0052]Referring to FIG. 10A-10C, a circular putter head 1000 is shown for explanation only to aid an understanding of the invention and has an upper portion 1004 and a lower portion 1008. The lower portion 1008 is made from a first material have 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 de...

Claims

1. A putter-type golf club head (1500, 1600) comprising: a toe end (1512, 1612), a heel end (1516, 1616), a strike face (1520, 1620), a rear end (1534, 1634), a crown (1536, 1636), a sole (1568, 1668), an upper portion (1504, 1604), and a lower portion (1508, 1608), wherein: the upper portion (1504, 1604) comprises a forward portion (1522, 1622) and a rearward extension (1524, 1624), wherein the rearward extension (1524, 1624) extends rearward from the forward portion towards the rear end (1534, 1634); the upper portion (1504, 1604) defines a central recess (1570, 1670) that is recessed into the upper portion (1505, 1604) via a recess floor (1574, 1674) and a circumferential recess wall (1572, 1672); the upper portion (1504, 1604) further comprises an alignment aid (1544, 1644), wherein the alignment aid comprises: a ball-outlining feature (1580, 1680) that circumscribes the central recess (1570, 1670), and comprises one or more arcuate portions (1582, 1682) and a set of parallel lines (1584, 1684), wherein the one or more arcuate portions are located near the strike face (1520, 1620), or the rear end (1634), the set of parallel lines (1584, 1684) extend from the strike face (1520, 1620) to the rear end (1534, 1634), and the ball-outlining feature (1580, 1680) comprises a first color; a central line (1576, 1676) situated on the recess floor (1574, 1674), wherein the central line (1576, 1676) is located within the ball-outlining feature (1580, 1680), and the central line (1576, 1676) comprises a second color; a plurality of grooves (1578. 1678) recessed into the recess floor (1574, 1674) on either side of the central line (1576, 1676); the lower portion (1508, 1608) comprises a central portion (1538, 1638), a toe mass, and a heel mass; the lower portion (1508, 1608) is configured to receive the upper portion (1504, 1604) such that the rearward extension (1524, 1624) is situated above the central portion (1538, 1638) and between the toe mass and the heel mass; and the upper portion (1504, 1604) comprises a first material having a first density and the lower portion (1508, 1608) comprises a second material having a second density, the first density is less than the second density, characterised in that the forward portion (1522, 1622) comprises the strike face (1520, 1620) such that an entirety of the strike face is integrally formed within the upper portion (1504, 1604).

2. The putter-type golf club head (1500, 1600) of claim 1, further comprising a volume and a mass; the lower portion (1508, 1608) comprising less than 35% of the volume of the putter type golf club head (1500, 1600); and the lower portion (1508, 1608) comprising greater than 50% of the mass of the putter type golf club head (1500, 1600).

3. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the second color is different from the first color.

4. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the putter type golf club head (1500, 1600) comprises a loft angle less than 7 degrees.

5. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein: the one or more arcuate portions (1582, 1682) comprise a first arcuate portion near the strike face and a second arcuate portion near the rear end; the set of parallel lines (1584, 1684) connect the first arcuate portion and the second arcuate portion to define a continuous perimeter around the central recess (1570, 1670); and the ball-outlining feature (1580, 1680) comprises an oblong shape.

6. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein: the one or more arcuate portions (1582, 1682) comprise a single arcuate portion near the strike face (1520, 1620); the set of parallel lines (1584, 1684) extend from the single arcuate portion toward the rear end (1534, 1634) to define a discontinuous perimeter around the central recess; and the ball-outlining feature (1580, 1680) comprises a U-shaped.

7. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the ball-outlining feature (1580, 1680) is recessed into the upper portion (1504, 1604) to define a channel.

8. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the ball-outlining feature (1580, 1680) protrudes outwardly from the upper portion (1504, 1604).

9. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein: the ball-outlining feature (1580, 1680) defines a width measured in a heel end to toe end direction; and the width of the ball-outlining feature (1580, 1680) is approximately 4.52 cm (1.78 inches).

10. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the upper portion (1504, 1604) is affixed to the lower portion (1508, 1608) via an adhesive.

11. The putter-type golf club head (1500, 1600) of claim 1 or claim 2, wherein the first material and the second material comprise a material selected from the group consisting of 8620 alloy steel, S25C steel, carbon steel, maraging steel, 17-4 stainless steel, 303 stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, and ADC-12.

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