Golf club head having supported striking face

Abstract

To focus on a golf club head having a multi-layered, multi-material striking face of the golf club head to improve the performance of the golf club head.SOLUTION: A golf club head having a supported striking face 910 is disclosed herein. More specifically, the golf club head in accordance with the present invention has a striking face, an internal support layer, and an intermediary sandwiched layer 926 juxtaposed between the striking face and the internal support layer.SELECTED DRAWING: Figure 20

Description

[Technical field]

[0001] The present invention relates generally to a golf club head having a polymer supported striking face, and more specifically, the golf club head according to the present invention further includes a striking face portion, an inner support layer, and an intermediate sandwich layer juxtaposed between the striking face portion and the inner support layer. [Background technology]

[0002] Modern golf club design has evolved since the early days of golf. The good news with all the technological advances in golf club technology is that the game of golf becomes easier for golfers of all skill levels. However, with all these advances come great challenges for the golf club engineer.

[0003] One of the latest trends in golf club design is to utilize multiple different materials in the same golf club head to take advantage of the individual performance properties of the base materials and combine them to create a better performing golf club head. U.S. Patent No. 5,316,298 (Hutin et al.) discloses a club head with a front striking face with a vibration damper on the rear surface. The vibration damper includes a constraining layer connected to the rear surface through an intervening viscoelastic material.

[0004] U.S. Patent No. 9,844,230 (Snyder) shows an iron body and a ball striking plate that engages the iron body. The ball striking plate may include a face layer and a backing layer of a polymeric material to separate the face layer from the iron body.

[0005] It should be noted that although the use of multi-material golf club heads has been done, the use of multiple materials around the striking face portion of the golf club head has always puzzled the industry due to the high stresses placed on the striking face when striking a golf ball. This invention focuses on a golf club head having a multi-layer, multi-material striking face to further improve the performance of the golf club head. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Patent No. 5,316,298 [Patent Document 2] U.S. Patent No. 9,844,230 Summary of the Invention

[0007] One aspect of the invention is an iron-type golf club having a golf club head, a grip, and a shaft therebetween, the golf club head having improved COR and feel. The golf club head is preferably comprised of a striking face portion positioned at a forward portion and a rear body portion attached to the striking face portion to form a cavity therebetween. The golf club head comprises a top line, a sole, a toe portion, a heel portion, and a hosel. In this invention, the striking face portion preferably has a thickness between 0.6 mm and 2.4 mm at the face center. The iron-type golf club head further comprises an inner support layer positioned within the cavity and connected to the rear body portion, and an intermediate sandwich layer juxtaposed between the striking face portion and the inner support layer. The intermediate sandwich layer is preferably comprised of a polymeric material having a sandwich face layer hardness of less than 75 Shore A and having a thickness between 1 mm and 10 mm at the face center. In an embodiment of the invention, the inner support layer abuts only between 25% and 75% of the intermediate sandwich layer. Further, the intermediate sandwich layer preferably abuts a significant amount of the striking face portion, preferably between 90% and 100% of the striking face portion. Most preferably, the inner support layer has a peripheral support portion that surrounds the cavity of the golf club head and has a width of 2 mm to 20 mm and a thickness of 0.5 mm to 5 mm. Thus, while the intermediate sandwich layer is supported by the peripheral portion, a substantial portion of the intermediate sandwich layer is not supported by the inner support layer. In one embodiment, the peripheral support portion is approximately 0.02 mm wide (W) adjacent the topline. TL is between 2mm and 5mm, and the sole width W S is between 6 mm and 20 mm. Preferably, the sole width W S is the top line width W TL is at least 1.5 times larger than

[0008] Another preferred embodiment of the present invention is an iron-type golf club having a golf club head, a grip, and a shaft therebetween, the golf club head having improved COR and feel. The golf club head is preferably comprised of a striking face portion positioned at a forward portion and a rear body portion attached to the striking face portion and forming a cavity therebetween. The golf club head comprises a top line, a sole, a toe portion, a heel portion, and a hosel. In this invention, the striking face portion preferably has a thickness between 0.6 mm and 2.4 mm at the face center. The iron-type golf club head further comprises an inner support layer connected to the rear body portion and positioned within the cavity, and an intermediate sandwich layer juxtaposed between the striking face portion and the inner support layer. The intermediate sandwich layer is preferably comprised of a polymeric material, which has a sandwich face layer hardness of less than 75 Shore A and has a thickness of 1 mm to 10 mm at the face center. The inner support layer abuts between 25% and 75% of the intermediate sandwich layer and has a peripheral support portion surrounding the cavity in the golf club head and a horizontal support section extending from a heel section of the peripheral support portion to a toe section of the peripheral support portion. Preferably, the horizontal support section has a horizontal support width W between 5 mm and 10 mm. H Additionally, the horizontal support section may include a central portion closer to the striking face portion such that the intermediate sandwich layer has a face center thickness that is between 80% and 40% of the intermediate sandwich layer thickness closer to the topline, sole, toe, or heel portion.

[0009] In an alternative embodiment of the present invention, the inner support layer abuts between 25% and 75% of the intermediate sandwich layer and has a peripheral support portion surrounding the cavity in the golf club head and a vertical support portion extending from a topline section of the peripheral support portion to a sole portion of the peripheral support portion. Preferably, the vertical support section has a vertical support width W between 8 mm and 15 mm.V Additionally, the vertical support section may include a central portion closer to the striking face portion such that the intermediate sandwich layer has a thickness at the face center that is between 80% and 40% of the intermediate sandwich layer thickness closer to the topline, sole, toe portion, or heel portion.

[0010] In a preferred embodiment, the inner support layer is constructed of steel and is integrally cast with the rear body section. In another preferred embodiment, the inner support layer is constructed of a thermoplastic material having a support tensile strength at least 10 times greater than the tensile strength of the middle sandwich layer.

[0011] In a preferred embodiment of the present invention, the striking face portion of the golf club head is very thin, more specifically, having a thickness of 1.4 mm to 1.8 mm at the face center. Additionally, the intermediate sandwich layer preferably has a thickness of 4 mm to 7 mm at the face center. Thus, the intermediate sandwich layer has a thickness that is more than twice the thickness of the striking face portion.

[0012] Yet another preferred embodiment of the present invention is an iron-type golf club having a golf club head, a grip, and a shaft therebetween, the golf club head having improved COR and feel. The iron-type golf club comprises a golf club head, a grip, and a shaft therebetween. Preferably, the head has a striking face portion located at a forward portion of the golf club head, and a rear body portion attached to the striking face portion and forming a cavity therebetween, the rear body portion forming a top line, a sole, a toe portion, a heel portion, and a hosel. Preferably, the striking face portion has a face center and has a thickness at the face center between 0.8 mm and 2.4 mm. Further, an inner support layer is connected to the rear body portion such that it is positioned within the cavity and has a forward-facing front surface, and an intermediate sandwich layer is juxtaposed between the striking face portion and the inner support layer. Preferably, the intermediate sandwich layer comprises a polymeric material having a thickness of 1 mm to 10 mm at the face center and a sandwich face layer tensile strength of between 4 MPa and 20 MPa. Preferably, the inner support layer comprises a thermoplastic material having a support layer tensile strength of between 60 MPa and 300 MPa and has a peripheral support portion surrounding the cavity. Preferably, the peripheral support portion has a peripheral width of between 2 mm and 20 mm and a thickness of between 0.5 mm and 5 mm. Most preferably, the striking face portion comprises a rear surface, and the forward surface of the intermediate sandwich layer abuts between 90% and 100% of the striking face portion's rear surface, while the inner support layer only abuts between 25% and 75% of the intermediate sandwich layer. In one embodiment, the inner support layer further comprises a horizontal support section extending from a heel section of the peripheral support portion to a toe section of the peripheral support portion. Preferably, the horizontal support section comprises a horizontal support width at least 10% greater than the peripheral width. In an alternative embodiment, the interior support layer further includes a vertical support section extending from the topline section of the peripheral support portion to the sole section of the peripheral support portion. [Brief description of the drawings]

[0013] The foregoing and other features and advantages of the present invention will become apparent from the following description of the invention as illustrated in the accompanying drawings, which are incorporated herein and form a part of the specification, and which further serve to explain the principles of the invention and enable one skilled in the relevant art to make and use the invention.

[0014] [Figure 1] FIG. 1 of the accompanying drawings shows a front view of a golf club head body portion in accordance with an embodiment of the present invention. [Diagram 2] FIG. 2 of the accompanying drawings shows a front view of a golf club head face cup which mates with the body portion disclosed in FIG. [Diagram 3] FIG. 3 of the accompanying drawings shows a golf club head intermediate layer juxtaposed between the body portion of FIG. 1 and the face cup of FIG. [Figure 4] FIG. 4 of the accompanying drawings shows a cross-sectional view of the golf club head according to FIGS. [Diagram 5] FIG. 5 of the accompanying drawings shows a front view of an alternative embodiment of the golf club head body of FIG. [Figure 6] FIG. 6 of the accompanying drawings shows a front view of an alternative embodiment of the golf club head body of FIG. [Figure 7] FIG. 7 of the accompanying drawings illustrates a cross-sectional view of an alternative embodiment of a golf club head in accordance with the present invention. [Figure 8] FIG. 8 of the accompanying drawings illustrates a front view of an alternative embodiment of the golf club head body of FIGS. [Figure 9] FIG. 9 of the accompanying drawings shows a front view of an alternative embodiment of the golf club head body of FIGS. [Figure 10] FIG. 10 of the accompanying drawings illustrates a front view of a golf club head body portion according to the alternative embodiment of the present invention of FIG. [Figure 11] FIG. 11 of the accompanying drawings shows a cross-sectional view of a portion of the golf club head of the embodiment of FIG. [Figure 12] FIG. 12 of the accompanying drawings illustrates a rear view of a golf club head in accordance with an embodiment of the present invention. [Figure 13] FIG. 13 of the accompanying drawings shows a perspective view of the rear body portion of the golf club head of FIG. [Figure 14] FIG. 14 of the accompanying drawings illustrates a cross-sectional view of a rear body portion of a golf club head in accordance with an embodiment of the present invention. [Figure 15] FIG. 15 of the accompanying drawings illustrates a cross-sectional view of the inner support layer of the golf club head of FIG. [Figure 16] FIG. 16 of the accompanying drawings shows a rear perspective view of the body portion of the golf club head of FIGS. [Figure 17] FIG. 17 of the accompanying drawings shows a perspective view of a golf club head in accordance with one embodiment of the present invention. [Figure 18] FIG. 18 of the accompanying drawings illustrates the rear body portion of the golf club head of FIG. [Figure 19] FIG. 19 of the accompanying drawings shows a toe view of the golf club head of FIG. [Figure 20] FIG. 20 of the accompanying drawings shows a cross-sectional view of the golf club head of FIG. [Figure 21] FIG. 21 of the accompanying drawings shows a perspective view of the rear body portion and face support of the golf club head of FIG. [Figure 22] FIG. 22 of the accompanying drawings shows a front view of an alternative embodiment of the rear body portion and face support of the golf club head of FIG. [Figure 23] FIG. 23 of the accompanying drawings shows a cross-sectional view of the face support of the golf club head of FIG. [Figure 24] FIG. 24 of the accompanying drawings illustrates a cross-sectional view of an alternative embodiment of a face support for the golf club head of FIG. [Diagram 25] FIG. 25 of the accompanying drawings shows a perspective view of an alternative embodiment of the rear body portion and face support of the golf club head of FIG. [Figure 26]FIG. 26 of the accompanying drawings illustrates a cross-sectional view of an alternative embodiment of a face support for the golf club head of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following detailed description describes the best currently contemplated modes of carrying out the invention. This description should not be construed as limiting the invention, but is provided merely for the purpose of illustrating the general principles of the invention. The scope of the invention is best defined by the appended claims. Various features of the invention will be described below, each of which can be used independently of one another or in combination with other features.

[0016] 1-4 of the accompanying drawings show a golf club head 100 in accordance with an exemplary embodiment of the present invention. Shown therein is a rear or body portion 102, which includes a topline portion 112, a toe portion 114, a sole portion 116, a heel portion 118, and a hosel 120. The body portion 102 is comprised of an interior face support 104, which includes a peripheral support portion 106 and a central portion 108. The peripheral support portion 106 is solid steel and is preferably cast with the body portion 102 so as to be rigid relative to the body portion 102. The peripheral support portion further surrounds a hollow central portion 108.

[0017] The striking face portion 110 shown in Figure 2 includes a front face portion 124, a turn-up portion 125, and a face center FC. Figure 2 further illustrates that the striking face portion 110 may be formed as a face cup to include a toe portion 115, a topline portion 113, and a sole portion 117 that form a leading edge LE and that join toe portion 114, topline portion 112, and sole portion 116, respectively, of the body portion. When the striking face portion 110 is joined to the body portion 102, preferably by welding around the striking face portion 110, the striking face portion 110 and the body portion 102 form a cavity between the front face portion 124 and the interior face support 104.

[0018] FIG. 3 shows an intermediate sandwich layer 126 sandwiched within a cavity between the rear surface of the front face portion 124 and the interior face support 104. The intermediate sandwich layer 126 has a front facing surface 127 that is substantially the same area as the front face portion 124. Preferably, the intermediate sandwich layer 126 is supported around its perimeter by the interior face support 104. That is, the intermediate sandwich layer 126 is supported by the interior face support peripheral support portions 106 near the topline portion 112, the toe portion 114, the sole portion 116, and the heel portion 118. However, the interior face support 104 includes a hollow central portion 108, which does not support the intermediate sandwich layer 126 as the peripheral support portions 106 do. Preferably, the central portion 108 circumscribes a projection of the face center FC, allowing the face center FC of the exterior front face portion 124 to flex upon impact to improve the overall striking face COR.

[0019] The outer front face portion 124 is preferably formed of steel and is disposed on the outer front portion of the striking face portion 110. The outer front face portion 124 has a substantially flat striking outer surface 132 including a plurality of grooves, not shown. More preferably, the outer front face portion 124 is formed of a high strength steel having an ultimate tensile strength of greater than 2000 MPa, more preferably greater than 2300 MPa. Most preferably, the outer front face portion 124 is formed of AerMet 340 or the like. Moreover, the outer front face portion 124 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the outer front face portion 124 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin outer front face portion 124 and its high strength assist in producing a high COR for the golf club head 100.

[0020] The inner face support 104 is formed within the inner hollow portion 129 of the golf club head 100. The inner face support 104 is preferably formed from steel having a tensile strength of about 400 MPa or greater and may be molded as part of the golf club head body portion 102 or may be formed from sheet metal and stamped or forged into shape and welded to the golf club head body portion 102. Preferably, the inner face support 104 has a thickness of between about 0.5 mm and 5 mm, and more preferably 0.8 mm to 2 mm.

[0021] The striking face portion 110 is abutted by an intermediate sandwich layer 126 that is juxtaposed between the front face portion 124 and the interior face support 104. Preferably, the intermediate sandwich layer 126 is supported around its periphery by the interior face support 104. That is, the intermediate sandwich layer 126 is supported along the topline, toe, sole and heel portions. This improves the COR of the entire striking face.

[0022] The intermediate sandwich layer 126 is a polymeric material having a tensile strength in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa, as measured according to ASTM D412. The intermediate sandwich layer 126 may be preformed and inserted into the cavity or may be injection molded into the cavity between the rear surface of the front face portion 124 and the inner face support 104. The outer front face portion has a very low tensile strength, which allows it to flex upon impact to help create a ball striking face portion with a very high COR. Additionally, to prevent the striking face portion from being too heavy, the specific gravity of the polymer is preferably between about 0.95 and 1.2, and the polymer has a Shore A hardness of less than 75, preferably between about 30 and 60. Preferably, the intermediate sandwich layer 126 is comprised of a silicone material, more preferably a silicone rubber, such as SH9151U sold by KCC Silicone. Additionally, intermediate sandwich layer 126 preferably has a substantially uniform thickness between about 1 mm and 10 mm, and more preferably between about 3 mm and 7 mm, and preferably has a thickness at least twice the thickness of the outer front face portion at face center FC.

[0023] As described above, the intermediate sandwich layer 126 is supported by the interior face support perimeter support portion 106 near the topline portion 112, the toe portion 114, the sole portion 116, and the heel portion 118. The perimeter support portion 106 preferably has a width between about 2 mm and 20 mm. More preferably, the perimeter support portion 106 has a first topline width W adjacent the topline portion 112 between about 2 mm and 5 mm. TL and a second sole width W adjacent the sole portion 116 between about 6 mm and 20 mm. S and a first width W TL1. The inner face support 104 further includes a hollow central portion 108 that does not support the intermediate sandwich layer 126, which covers 90% to 100% of the rear surface of the front face portion 124, but only abuts between 25% and 75% of the rear surface of the intermediate sandwich layer. Thus, while the front face portion 124 is substantially cushioned by the intermediate sandwich layer 126, between 75% and 25% of the intermediate sandwich layer 126 is not constrained by the inner face support 104. Preferably, the central portion 108 surrounds the face center FC protrusion, which allows the face center FC of the outer front face portion 124 to flex upon impact, improving the COR of the entire striking face.

[0024] FIG. 5 shows an alternative embodiment of the body disclosed in FIG. 1, and discloses another embodiment that may be used with the striking face portion 110 and intermediate sandwich layer 126 described above with reference to FIG. 2 and FIG. 3, respectively. The golf club head 200 shown here comprises a rear body portion or body section 202 including a topline portion 212, a toe portion 214, a sole portion 216, a heel portion 218, and a hosel 220. The body section 202 has an interior face support 204, which includes a peripheral support portion 206 and a central portion 208. The peripheral support portion 206 is solid steel and is preferably cast with the body section 202 so as to be rigid relative to the body section 202. The peripheral support portion 206 further surrounds a hollow central portion 208. This embodiment further includes a vertical support portion 222 that divides the hollow central portion 208 into a hollow toe portion 208a and a hollow heel portion 208b. In this embodiment, the vertical support portion 222 is solid steel and is preferably cast with the body portion 202.

[0025] As described above, the intermediate sandwich layer 126 is supported by the perimeter support portion 206 of the internal face support 204 near the topline portion 212, the toe portion 214, the sole portion 216, and the heel portion 218. The intermediate sandwich layer 126 is also supported by the vertical support portion 222 of the internal face support 204 rearward of the face center FC. The perimeter support portion 206 preferably has a width between about 2 mm and 20 mm. More preferably, the perimeter support portion has a first topline width W of about 2 mm to 5 mm adjacent the topline portion 212. TL and a second sole width W adjacent the sole portion 216 of about 6 mm to 20 mm. S and a second sole width W S is the first top line width W TL In addition, the inner face support 204 has hollow central portions 208a and 208b that do not support the middle sandwich layer 126, and the inner face support 204 abuts between 25% and 75% of the back surface of the middle sandwich layer 126, such that 75% to 25% of the middle sandwich layer 126 is unconstrained. In this embodiment, the vertical support portions 222 are at least 1.5 times the vertical support length L V and vertical support width W V Vertical support length L V is measured from the topline section of the perimeter support portion 206 to the sole section of the perimeter support portion 206. Preferably, the vertical support length L V is between about 15 mm and 30 mm, and the vertical support width W V is between about 8 mm and 15 mm. Most preferably, the vertical support width W V is the vertical support length L V In this manner, the COR of the striking face portion 110 at the face center FC can be controlled to be similar to the COR at ½ inch from the face center FC toward the toe and ½ inch from the face center FC toward the heel.

[0026] FIG. 6 discloses an alternative embodiment of the body disclosed in FIG. 1, which may be used with the striking face portion 110 and intermediate sandwich layer 126 as described above with reference to FIG. 2 and FIG. 3, respectively. The golf club head 300 shown here has a rear body portion or body section 302 including a topline portion 312, a toe portion 314, a sole portion 316, a heel portion 318, and a hosel 320. The body section 302 is further comprised of an interior face support 304 including a perimeter support portion 306 and a central portion 308. The perimeter support portion 306 is solid steel and is preferably cast with the body section 302 to provide rigidity thereto. The perimeter support portion 306 further surrounds a hollow central portion 308. This embodiment further includes a horizontal support portion 322 that divides the hollow central portion 308 into a hollow top portion 308a and a hollow bottom portion 308b. In this embodiment, the horizontal support portion 322 is solid steel and is preferably cast with the body portion 302 .

[0027] As described above, the intermediate sandwich layer 126 is supported by the perimeter support portion 306 of the internal face support 304 near the topline portion 312, the toe portion 314, the sole portion 316, and the heel portion 318. The intermediate sandwich layer 126 is also supported by the horizontal support portion 322 of the internal face support 304 rearward of the face center FC. The perimeter support portion 306 preferably has a width between about 2 mm and 20 mm. More preferably, the perimeter support portion has a first topline width W adjacent the topline portion 312 between about 2 mm and 5 mm. TL and a second sole width W adjacent the sole portion 316 between about 6 mm and 20 mm. S and a second sole width W S is the first top line width W TLIn addition, the inner face support 304 has hollow central portions 308a and 308b that do not support the middle sandwich layer 126, and the inner face support 304 abuts between 25% and 75% of the back surface of the middle sandwich layer 126, such that between 75% and 25% of the middle sandwich layer 126 is unconstrained. In this embodiment, the horizontal support portion 322 has a horizontal support length L H and horizontal support width W H Horizontal support length L H is measured from the heel portion of the perimeter support portion 306 to the toe portion of the perimeter support portion 306. Preferably, the horizontal support length L H is between about 40mm and 80mm, and the horizontal support width W H is between about 5 mm and 10 mm. Most preferably, the horizontal support width W H is the horizontal support length L H This makes it possible to control the COR of the striking face portion 110 at the face center FC over the entire striking face portion 110, thereby achieving a solid feel.

[0028] 7 and 8 of the accompanying drawings show a golf club head 400 in accordance with an exemplary embodiment of the present invention. The golf club head 400 shown has a rear body or main body portion 402 including a topline portion 412, a toe portion 414, a sole portion 416, a heel portion 418, and a hosel 420. The golf club head 400 further has a striking face portion 410 that is preferably joined to the main body portion 402 by welding or integral casting to form a cavity therebetween. The golf club head 400 further has an internal face support 404 that includes a peripheral support portion 406 and a central portion 408. The peripheral support portion 406 is preferably a thermoplastic insert disposed within the main body portion 402 such that it is rigid relative to the main body portion 402. The peripheral support portion 406 further surrounds the hollow central portion 408. This embodiment further includes a vertical support portion 422 that divides the hollow central portion 408 into a hollow toe portion 408a and a hollow heel portion 408b.

[0029] The striking face portion 410 shown in FIG. 7 includes a front face portion 424 that comprises a face center. The front face portion 424 may be formed as a face cup, thus forming a leading edge LE, and includes a toe portion, a topline portion, and a sole portion that are preferably joined by welding to the toe portion 414, the topline portion 412, and the sole portion 416 of the body portion, respectively. The outer front face portion 424 is preferably formed of steel and is positioned on the outer front portion of the striking face portion 410. The outer front face portion 424 includes a substantially flat striking outer surface 432 that includes a plurality of grooves (not shown). More preferably, the outer front face portion 424 is formed of a high strength steel having an ultimate tensile strength of greater than 2000 MPa, more preferably greater than 2300 MPa. Most preferably, the outer front face portion 424 is formed of AerMet 340 or the like. Further, the outer front face portion 424 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the outer front face portion 424 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin outer front face portion 424 and its high strength help generate a high COR for the golf club head 400. Alternatively, the striking face portion 410 may be integrally cast of steel, similar to the body portion 402.

[0030] An intermediate sandwich layer, such as the intermediate sandwich layer 426 shown in FIG. 4, is sandwiched within a cavity between the rear surface of the front face portion 424 and the interior face support 404. The intermediate sandwich layer 426 has a front facing surface 425 that is substantially coextensive with the rear surface of the front face portion 424. Preferably, the intermediate sandwich layer 426 is supported at its periphery by the interior face support 404. That is, the intermediate sandwich layer 426 is supported by the interior face support peripheral support portions 406 near the topline portion 412, the toe portion 414, the sole portion 416, and the heel portion 418. However, the interior face support 404 includes a hollow central portion 408 that does not support the intermediate sandwich layer 426 as the peripheral support portions 406 do, thereby allowing the intermediate sandwich layer 426 to be at least partially unconstrained.

[0031] The inner face support 404 is secured within the inner hollow portion 429 of the golf club head 400. The inner face support 404 is preferably formed from a thermoplastic material or thermoplastic composite material having a tensile strength of about 60 MPa to 300 MPa and a flexural modulus of about 2000 MPa to 8000 MPa. Preferably, the inner face support 404 has a thickness of about 0.5 mm to 5 mm, more preferably about 0.8 mm to 2 mm.

[0032] As mentioned above, the intermediate sandwich layer 426 is a polymeric material having a tensile strength, as measured according to ASTM D412, in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa. The very low tensile strength allows the outer face portion to flex upon impact, which helps to create a striking face portion with a very high COR. Furthermore, to prevent the striking face portion from being too heavy, the specific gravity of the polymer is preferably between about 0.95 and 1.2, and the polymer has a Shore A hardness of less than 75, preferably between about 30 and 60. Preferably, the intermediate sandwich layer 426 is comprised of a silicone material, more preferably a silicone rubber, such as SH9151U sold by KCC Silicone Corporation. Furthermore, the intermediate sandwich layer 426 preferably has a substantially uniform thickness of between about 1 mm to 10 mm, more preferably between about 3 mm to 7 mm. The intermediate sandwich layer 426 also preferably has a thickness at the face center FC that is at least twice the thickness of the outer front face portion.

[0033] As discussed above, the peripheral support portion 406 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion has a first topline width W adjacent the topline portion 412 of about 2 mm to 5 mm. TL and a second sole width W adjacent the sole portion 416 of about 6 mm to 20 mm. S and a first width W TL 4. Additionally, the interior face support 404 includes a hollow central portion 408 that does not support the intermediate sandwich layer 426 and only abuts between 25% and 75% of the rear surface of the intermediate sandwich layer, while the intermediate sandwich layer 426 covers between 90% and 100% of the rear surface of the exterior front face portion 424. Thus, although the exterior front face portion 424 is substantially damped by the intermediate sandwich layer 426, between 75% and 25% of the intermediate sandwich layer 426 is not restrained by the interior face support 404. In this embodiment, the vertical support portion 422 has a vertical support length LV and vertical support width W V Vertical support length L V is measured from the topline section of the perimeter support portion 406 to the sole section of the perimeter support portion 406. Preferably, the vertical support length L V is between about 15 mm and 30 mm, and the vertical support width W V is between about 8 mm and 15 mm. Most preferably, the vertical support width W V is the vertical support length L V In this manner, the COR of the striking face portion 410 at the face center FC can be controlled to be similar to the COR at ½ inch from the face center FC toward the toe and ½ inch from the face center FC toward the heel.

[0034] 9 of the accompanying drawings illustrates a golf club head body portion 502 that can be combined with the striking face portion 110 disclosed in FIG. 2. According to an exemplary embodiment of the present invention, the rear body portion or body portion 502 includes a topline portion 512, a toe portion 514, a sole portion 516, a heel portion 518, and a hosel 520. The golf club head further includes a striking face portion 110 that is preferably joined to the body portion 502 by welding or integral casting to form a cavity therebetween. The golf club head further includes an internal face support 504 that includes a peripheral support portion 506 and a central portion 508. The peripheral support portion 506 is preferably a thermoplastic insert that is disposed within the body portion 502 and is thus rigid relative to the body portion 502. The peripheral support portion 506 further surrounds the hollow central portion 508. This embodiment further includes a horizontal support portion 522 that divides the hollow central portion 508 into a hollow toe portion 508a and a hollow heel portion 508b.

[0035] As before, the striking face portion 110 shown in FIG. 2 includes a front face portion 124 having a face center FC. The front face portion 124 may be formed as a face cup, thus forming a leading edge LE, and including a toe portion, a topline portion, and a sole portion that are joined, preferably by welding, to a toe portion 514, a topline portion 512, and a sole portion 516 of the body portion, respectively. The outer front face portion 124 is preferably formed of steel and is positioned on the outer front portion of the striking face portion 110. The outer front face portion 124 has a substantially flat striking outer surface that includes a plurality of grooves, not shown. More preferably, the outer front face portion 124 is formed of a high strength steel having an ultimate tensile strength of greater than 2000 MPa, more preferably greater than 2300 MPa. Most preferably, the outer front face portion 124 is formed of AerMet 340 or the like. Additionally, the outer front face portion 124 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the outer front face portion 124 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin outer front face portion 124 and its high strength help create a high COR for the golf club head. Alternatively, the striking face portion 110 may be cast integrally with the body portion 102 and formed from the same steel.

[0036] An intermediate sandwich layer, such as the intermediate sandwich layer 126 shown in FIG. 3, is sandwiched in a cavity between the rear surface of the front face portion 124 and an interior face support 504. The intermediate sandwich layer 126 has a front facing surface 127 that is substantially coextensive with the rear surface of the front face portion 124. Preferably, the intermediate sandwich layer 126 is supported at its periphery by the interior face support 504. That is, the intermediate sandwich layer 126 is supported by the interior face support periphery support portions 506 near the topline portion 512, the toe portion 514, and the sole portion. However, the interior face support 504 has a hollow central portion 508 that does not support the intermediate sandwich layer 126 like the support portions 506, such that the intermediate sandwich layer 126 is at least partially unconstrained.

[0037] The inner face support 504 is secured to the inner hollow portion of the golf club head. The inner face support 504 is preferably formed from a thermoplastic material or a thermoplastic composite material having a tensile strength of about 60 MPa to 300 MPa and a flexural modulus of about 2000 MPa to 8000 MPa. Preferably, the inner face support 504 has a thickness of between about 0.5 mm to 5 mm, more preferably between about 0.8 mm to 2 mm.

[0038] As mentioned above, the intermediate sandwich layer 126 is a polymeric material having a tensile strength, as measured according to ASTM D412, in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa. The very low tensile strength allows the outer front face portion to flex upon impact, helping to create a striking face portion with a very high COR. Furthermore, to prevent the striking face portion from being too heavy, the specific gravity of the polymer is preferably between about 0.95 and 1.2, and the polymer also has a Shore A hardness of less than 75, preferably between about 30 and 60. Preferably, the intermediate sandwich layer 126 is comprised of a silicone material, more preferably a silicone rubber, such as SH9151U sold by KCC Silicone Corporation. Furthermore, the intermediate sandwich layer 126 preferably has a substantially uniform thickness of about 1 mm to 10 mm, more preferably between about 3 mm to 7 mm. Additionally, intermediate sandwich layer 126 preferably has a thickness at face center FC that is at least twice the thickness of the outer front face portion.

[0039] As discussed above, the peripheral support portion 506 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion has a first topline width W adjacent the topline portion 512 of about 2 mm to 5 mm. TL and a second sole width W adjacent the sole portion 516, the second sole width W being about 6 mm to 20 mm. S and a second sole width W S is the first width W TL2. In addition, the inner face support 504 includes a hollow central portion 508 that does not support the middle sandwich layer 126, but only abuts 25%-75% of the back surface of the middle sandwich layer 126, yet covers 90%-100% of the middle sandwich layer 126. Thus, although the outer front face portion 124 is substantially damped supported by the middle sandwich layer 126, 75%-25% of the middle sandwich layer 126 is not restrained by the inner face support 504. In this embodiment, the horizontal support portion 522 has a horizontal support length L H and horizontal support width W H Horizontal support length L H is measured from the heel portion of the perimeter support portion 506 to the toe portion of the perimeter support portion 506. Preferably, the horizontal support length L H is between about 40mm and 80mm, and the horizontal support width W H is between about 5 mm and 10 mm. Most preferably, the horizontal support width W H is the horizontal support length L H This makes it possible to control the COR of the striking face portion 110 at the face center FC over the entire striking face portion 110, thereby achieving a solid feel.

[0040] 10 and 11 disclose an alternative embodiment of the golf club head body disclosed in FIG. 5, which may be used with striking face portion 110 and intermediate sandwich layer 126 in place of body portion 202, as described above with reference to FIGS. 2 and 3, respectively. The golf club head 600 shown here comprises a rear body portion or body section 602, which includes a topline portion 612, a toe portion 614, a sole portion 616, a heel portion 618, and a hosel 620. The body portion 602 further has an internal face support 604, which includes a perimeter support portion 606 and a central portion 608. The perimeter support portion 606 is solid steel and is preferably cast with the body portion 602 so as to be rigid relative to the body portion 602. The perimeter support portion 606 further surrounds a hollow central portion 608. This embodiment further includes a vertical support portion 622, which divides the hollow central portion 608 into a hollow toe portion 608a and a hollow heel portion 608b. In this embodiment, the vertical support portion 622 is solid steel and is preferably cast with the body portion 602.

[0041] As described above, the intermediate sandwich layer 126 is supported by the perimeter support portion 606 of the internal face support 604 near the topline portion 612, the toe portion 614, the sole portion 616, and the heel portion 618. The intermediate sandwich layer 126 is also supported by the vertical support portion 622 of the internal face support 604 rearward of the face center FC. The perimeter support portion 606 preferably has a width between about 2 mm and 20 mm. More preferably, the perimeter support portion has a first topline width W of about 2 mm to 5 mm adjacent the topline portion 612. TL and a second sole width W adjacent the sole portion 616, the second sole width W being about 6 mm to 20 mm. S and a second sole width W S is the first top line width W TLIn addition, the inner face support 604 has hollow central portions 608a and 608b that do not support the middle sandwich layer 126, and the inner face support 604 abuts the back surface of the middle sandwich layer 126 between 25% and 75% of the middle sandwich layer 126, such that 75% to 25% of the middle sandwich layer 126 is unconstrained. In this embodiment, the vertical support portion 622 has a vertical support length L VA , L VB , and L VC and vertical support width W V The vertical support length L VA , L VB , and L VC is measured from the topline section of the perimeter support portion 606 to the sole section of the perimeter support portion 606. Preferably, the vertical support length L VA , L VB , and L VC is between about 15 mm and 30 mm, and the vertical support width W V is between about 8 mm and 15 mm. Most preferably, the vertical support width W V is the vertical support length L VA , L VB , and L VC 3. The COR of the striking face portion 110 at the face center FC can thus be controlled to be similar to the COR at ½ inch from the face center FC toward the toe and ½ inch from the face center FC toward the heel. In this embodiment, the vertical support portion 622 is further divided into three portions: a central vertical support portion 622a, a top vertical support portion 622b, and a bottom vertical support portion 622c. Preferably, the central vertical support portion 622a is substantially closer to the striking face portion 110 such that the intermediate sandwich layer 126 is substantially closer to the striking face portion 110 at the face center than the second peripheral thickness t P A first thickness t FCAs shown, the top vertical support portion 622b and the bottom vertical support portion 622c join the central vertical portion 622 to the peripheral support portion 606, but are angled from the peripheral support portion 606 toward the striking face portion 110. Thus, the first thickness t FC a second perimeter thickness t of 1 / 2 inch from the face center toward the toe portion 614 and the heel portion 618 P Preferably, the central vertical support portion 622a is between about 80% and 40% of the central vertical support length L VA , the top vertical support portion 622b has a top vertical support length L VB and the bottom vertical support portion 622c has a bottom vertical support length L VC In a preferred embodiment, the central vertical support length L VA is the top vertical support length L VB and bottom vertical support length L VC In such an embodiment, the COR of the striking face portion 110 can be kept more constant near the face center FC.

[0042] 12 and 13 of the accompanying drawings show a golf club head 700 and a golf club head body portion 702, respectively. According to an exemplary embodiment of the present invention, the rear body portion or body portion 702 includes a topline portion 712, a toe portion 714, a sole portion 716, a heel portion 718, and a hosel 720 and may be integrally cast with a striking face portion 710. The golf club head further includes an inner face support 704, which includes a support bar portion 706, a central support portion 705, and a plurality of openings 708. The inner face support 704 is preferably a thermoplastic insert having a support layer tensile strength of 60 MPa to 300 MPa and a flexural modulus of approximately 2000 MPa to 8000 MPa that is positioned within the body portion 702 so as to be rigid relative to the body portion 702. The inner face support 704 is preferably coupled to the body portion 702 by abutting or snapping against a plurality of lip portions 732 on the inside of the body portion 702, or by fasteners 730 positioned near the heel portion 718. The support bar portion 706 is spaced from the topline portion 712 to facilitate insertion into the body portion 702, thus forming a gap 734 between the topline portion 712 and the support bar portion 706. Preferably, the central support portion 705 has a thickness of between about 0.5 mm and 5 mm, more preferably between about 0.8 mm and 2 mm. For structural stability, the support bar portion 706 has a width W of between about 2 mm and 5 mm. SB and a thickness at least 1.5 times the thickness of central support portion 705.

[0043] 7 is sandwiched within a cavity between the rear surface of the striking face portion 710 and the inner face support. The intermediate sandwich layer 726 has a front facing surface having substantially the same area as the rear surface of the striking face portion 710. Preferably, the inner face support 704 has a plurality of openings 708 and gaps 734 that do not support the intermediate sandwich layer 726. Thus, the inner face support 704 only abuts between 25% and 75% of the rear surface of the intermediate sandwich layer, yet the intermediate sandwich layer 726 covers between 90% and 100% of the rear surface of the striking face portion 710.

[0044] As mentioned above, the intermediate sandwich layer 726 is a polymeric material having a tensile strength, as measured according to ASTM D412, in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa. The very low tensile strength allows the outer front face portion to flex upon impact, helping to create a striking face portion with a very high COR. Furthermore, to prevent the golf club head 700 from being too heavy, the specific gravity of the polymer is preferably between about 0.95 and 1.2, and the polymer has a Shore A hardness of less than 75, preferably between about 30 and 60. Preferably, the intermediate sandwich layer 726 comprises a silicone material, more preferably a silicone rubber, such as SH9151U sold by KCC Silicone Corporation. Furthermore, the intermediate sandwich layer 726 preferably comprises a substantially uniform thickness of about 1 mm to 10 mm, more preferably between about 3 mm to 7 mm. The intermediate sandwich layer 726 is also preferably at least twice as thick as the thickness of the striking face portion 710 at the face center FC.

[0045] 14-16 of the accompanying drawings show a portion of a golf club head 800. In accordance with an exemplary embodiment of the present invention, a rear or body portion 802 includes a toe portion 814, a sole portion 816, a heel portion 818, and a hosel 820, which may be integrally cast with a striking face portion 810. The golf club head further includes a topline portion 812, a central support portion 805, and an inner face support 804 including a plurality of openings 808. As above, the inner face support 804 is preferably a thermoplastic insert having a support layer tensile strength of between 60 MPa and 300 MPa, and a flexural modulus of between about 2000 MPa and 8000 MPa, and disposed within the body portion 802 such that it is rigid relative to the body portion 802. The inner face support 804 is preferably coupled to the body portion 802 by abutting or snapping onto a plurality of lip portions 832 on the inside of the body portion 802 and ledge portions 834 on the toe portion 814 and heel portion 818. Fasteners may be incorporated as desired. Preferably, the central support portion 805 has a thickness of between about 0.5 mm and 5 mm, more preferably between about 0.8 mm and 2 mm.

[0046] 12 is preferably sandwiched in a cavity between the rear surface of the striking face portion 810 and the interior face support 804. Preferably, the interior face support 804 includes a plurality of openings 808 that do not support the intermediate sandwich layer 726. The interior face support 804 preferably abuts only 25% to 75% of the rear surface of the intermediate sandwich layer, while the intermediate sandwich layer 726 covers 90% to 100% of the rear surface of the striking face portion 810.

[0047] 17-21 of the accompanying drawings illustrate a golf club head 900 in accordance with an exemplary embodiment of the present invention. The golf club head 900 shown includes a rear body portion or body portion 902 including a topline portion 912, a toe portion 914, a sole portion 916, a heel portion 918, and a hosel 920. The golf club head 900 includes a striking face portion 910, a return portion 925, and a face center FC. Additionally, the striking face portion 910 may be formed as a face cup to define a leading edge LE.

[0048] As shown in FIG. 18, the body portion 902 further comprises an inner face support portion 904 including a C-shaped horizontal support portion 906 extending from a toe portion 914 to a heel portion 918. The C-shaped horizontal support portion 906 is preferably steel and is preferably cast with the body portion 902 or joined thereto, for example by welding, so as to be integral therewith. As shown in FIG. 20, an intermediate sandwich layer 926 is juxtaposed between the C-shaped support portion 906 and the striking face portion 910. The C-shaped horizontal support portion 906 may include an upper wall 940 and a lower wall 942 for firmly supporting the intermediate sandwich layer 926, as best shown in FIG. 23. The horizontal support portion has a horizontal support width WIS and a horizontal support length LIS substantially similar to the intermediate sandwich layer length LISL and the intermediate sandwich layer width WISL, as shown in FIG. 21 and FIG. 23. Upper wall 940 has an upper wall width WUW and lower wall 942 has a lower wall width WLW, both of which are preferably less than 75% of the intermediate sandwich layer thickness tISL, and more preferably between 20% and 75% of the intermediate sandwich layer thickness tISL, which allows intermediate sandwich layer 926 to deform upon impact and increases the COR of striking face portion 910.

[0049] In this embodiment, a C-shaped horizontal support portion 906 divides the hollow central portion 908 into a hollow top portion 908a and a hollow bottom portion 908b. In this embodiment, the middle sandwich layer 926 contacts 10%-25% of the back surface of the striking face portion 910. Furthermore, in this embodiment, the horizontal support portion 906 has a horizontal support length LIS and a horizontal support width WIS. The horizontal support length LIS is measured from the heel portion to the toe portion as shown in FIG. 18. Preferably, the horizontal support length LIS is about 40mm-80mm and the horizontal support width WIS is about 5mm-10mm. Most preferably, the horizontal support width WIS is about 5%-25% of the horizontal support length LIS. Also, the horizontal support length LIS is at least four times the horizontal support width WIS. Similarly, as partially shown in FIG. 21 and FIG. 23, the intermediate sandwich layer length LISL is about 40 mm to 80 mm, the intermediate sandwich layer width WISL is about 5 mm to 10 mm, and the intermediate sandwich layer thickness tISL is about 5 mm to 10 mm. Most preferably, the intermediate sandwich layer width WISL is about 5% to 25% of the intermediate sandwich layer length LISL. Also, the intermediate sandwich layer length LISL is at least four times the intermediate sandwich layer width WISL and the intermediate sandwich layer thickness tISL. This allows the COR of the striking face portion 910 at the face center FC to be controlled throughout the striking face portion 910 from the heel portion 918 to the toe portion 914, and provides a solid feel.

[0050] The striking face portion 910 is preferably formed from steel. The striking face portion 910 has a substantially flat outer striking surface 932 that includes a plurality of grooves (not shown). The striking face portion 910 is preferably formed from a high strength steel having an ultimate tensile strength of greater than 2000 MPa, and more preferably greater than 2300 MPa. Most preferably, the striking face portion 910 is formed from AerMet 340 or the like. Additionally, the striking face portion 910 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the striking face portion 910 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin striking face portion 910 and its high strength help to create a high COR for the golf club head 900.

[0051] The striking face portion 910 is in contact with an intermediate sandwich layer 926 juxtaposed between the striking face portion 910 and the inner face support 904. The intermediate sandwich layer 926 is preferably a polymeric material having a tensile strength in the range of about 5 MPa to 600 MPa, more preferably 10 MPa to 500 MPa, and most preferably 15 MPa to 300 MPa, as measured in accordance with ASTM D412. The intermediate sandwich layer 926 is preferably preformed and inserted into the C-shaped support portion 906 through the toe opening 930 and then covered with a toe cap 931.

[0052] FIG. 22 discloses a second embodiment of the intermediate sandwich layer 926 made of multiple materials. The intermediate sandwich layer 926 is composed of a first portion 926a located approximately in the center of the intermediate sandwich layer 926, adjacent to the face center FC, and having a first hardness, a second portion 926b located in a toe portion of the intermediate sandwich layer 926, having a second hardness lower than the first hardness, and a third portion 926c located in a heel portion of the intermediate sandwich layer 926, having a third hardness lower than the first hardness. The second portion 926b and the third portion 926c may be made of the same material, and therefore the second hardness and the third hardness may be equal. The length of the first portion La is shorter than the sum of the length of the second portion Lb and the length of the third portion Lc. More preferably, the first length La is equal to or less than 1 / 2(Lb+Lc). Additionally, the material of the first portion 926a has a tensile strength of about 5 MPa to 600 MPa, more preferably 10 MPa to 500 MPa, and most preferably 15 MPa to 300 MPa, as measured according to ASTM D412. The material of the second portion 926b and the material of the third portion 926c preferably have a tensile strength of about 2 MPa to 100 MPa, and more preferably 5 MPa to 50 MPa, as measured according to ASTM D412. In another embodiment, the first portion 926a, the second portion 926b, and the third portion 926c can be formed of the same material, but the second portion 926b and the third portion 926c include a foaming agent to foam the material to a density less than 0.9 g / cm3, thereby reducing the hardness. The amount of foaming agent can be the same in the second portion 926b and the third portion 926c, or can vary such that one portion is a less dense foam than the other. That is, the specific gravity of the second portion 926b can be equal to or less than the specific gravity of the third portion 926c, and the specific gravity of the second portion 926b and the third portion 926c is less than the specific gravity of the first portion 926a. The very low tensile strength allows the outer front portion to flex upon impact, which helps create a striking face portion with a very high COR. Additionally, to keep the striking face portion from being too heavy, the specific gravity of the polymer is preferably between about 0.5 and 1.2.

[0053] Preferably, intermediate sandwich layer 926 is comprised of a polymer having a hardness between 30 Shore A and 60 Shore D, preferably between about 50 Shore A and 50 Shore D, and most preferably between about 75 Shore A and 80 Shore C. Preferably, intermediate sandwich layer 926 is comprised of a silicone material, more preferably a silicone rubber, such as SH9151U sold by KCC Silicone Corporation. Further, intermediate sandwich layer 926 has a substantially uniform thickness of about 1 mm to 10 mm, more preferably a thickness of about 3 mm to 7 mm. It is also preferred that intermediate sandwich layer 926 is at least twice as thick as the thickness of the outer front face portion at face center FC.

[0054] In another embodiment, the middle sandwich layer 926 is preferably formed from a material having a resilience of greater than 50%, more preferably greater than 80%. Preferred materials include ion exchange resins such as Dow SURLYN 8120 and 8320, although highly neutralized ion exchange resins such as Dow HPF 1000 are preferred. In another preferred embodiment, a material with a hardness of less than 50 Shore D, a resilience of greater than 50%, and a density of less than 0.9 g / cm3, such as Dow FUSABON DN525, works very well due to its resilience and low density.

[0055] 24, the intermediate sandwich layer 926 may comprise a C-shaped member formed of an elastomeric or metallic material. The front surface of the intermediate sandwich layer 926 is convex relative to the striking face portion 910 and is compressed to form a contact width CW that is less than the intermediate sandwich layer width WISL. More preferably, the front surface of the intermediate sandwich layer 926 is convex relative to the striking face portion 910 and has a radius of curvature between 10 mm and 50 mm such that when compressed, the front surface of the intermediate sandwich layer 926 forms a contact width CW that is less than 75% of the intermediate sandwich layer width WISL and more than 20% of the intermediate sandwich layer width WISL. When the intermediate sandwich layer 926 is formed of a metal, such as aluminum or titanium, it is preferably formed from a thin sheet having a thickness of less than 5 mm and more than 1 mm, and is formed to fit between the upper wall 940 and the lower wall 942.

[0056] 25 and 26, the inner face support 904 includes an L-shaped horizontal support portion 905 that extends from the toe portion 914 to the heel portion 918 and is comprised of a rear wall 944 and a bottom wall 946. The body portion 902 and the hitting face portion 910 form a hollow center portion 908. The horizontal support portion 905 compresses the intermediate sandwich layer 926 between the rear wall 944 and the hitting face portion 910. The dimensions and function of the horizontal support portion 905 are the same as described above. The difference in this embodiment is that the intermediate sandwich layer 926 can be inserted through a body opening 948 under the topline portion 912 of the body portion 902. The body opening 948 can then be covered with a medallion 950. Another advantage of this embodiment is that the intermediate sandwich layer 926 is more easily compressed since it is not supported by the top wall 940, giving the hitting face portion 910 more resilience.

[0057] Other than in the working examples, or unless otherwise indicated, all numerical ranges, amounts, values, and percentages in the preceding specification, such as amounts of materials, moments of inertia, center of gravity locations, lofts, draft angles, various performance ratios, etc., may be understood as if preceded by the term "about" even if the term "about" does not explicitly appear in the value, amount, or range. Accordingly, unless otherwise indicated, the numerical parameters set forth in the foregoing specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed at least in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0058] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, such numerical values ​​inherently contain certain errors resulting from the standard deviation found in their respective testing measurements. Further, when numerical ranges of various scopes are set forth herein, it is to be noted that any combination of these values ​​inclusive of the recited values ​​may be used.

[0059] Of course, it will be understood that the foregoing relates to exemplary embodiments of the invention and that modifications can be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. In iron type golf clubs, The golf club has a golf club head, a grip, and a shaft therebetween; The golf club head is a striking face portion positioned on a front portion of the golf club head, the striking face portion having a striking face portion face center, a striking face portion rear surface, and a thickness at the face center between 0.6 mm and 2.4 mm; a rear body portion coupled to the striking face portion, forming a cavity between the striking face portion and defining a topline portion, a sole portion, a toe portion, a heel portion, and a hosel; an inner support layer positioned within the cavity and coupled to the rear body portion, the inner support layer having a horizontal support portion extending from the toe portion to the heel portion and including an inner support layer front surface; an intermediate sandwich layer juxtaposed between the striking face portion and the inner support layer and made of a polymeric material having a sandwich face layer hardness of less than 75 Shore A, the intermediate sandwich layer having a thickness of 1 mm to 10 mm at the face center and having an intermediate sandwich layer front surface adjacent the striking face portion and an intermediate sandwich layer rear surface, the inner support layer front surface abutting the intermediate sandwich layer rear surface; The intermediate sandwich layer has a sandwich layer width and a sandwich layer length that is at least four times greater than the sandwich layer thickness and the sandwich layer width.

2. 2. The iron-type golf club of claim 1, wherein the intermediate sandwich layer length is between 90% and 110% of the striking face portion length (length of the groove at the face center).

3. 2. The iron-type golf club of claim 1, wherein the horizontal support portion is C-shaped to have upper and lower walls abutting the intermediate sandwich layer, the upper wall having an upper wall width and the lower wall having a lower wall width, the upper wall width and the lower wall width being less than 75% of the sandwich layer thickness.

4. 2. The iron-type golf club of claim 1, wherein the rear body portion has a toe opening at the toe portion having a first shape, and the intermediate sandwich layer has a cross-sectional shape similar to the first shape such that the intermediate sandwich layer is inserted into the cavity through the toe opening.

5. 5. The iron-type golf club according to claim 4, wherein the rear body further includes a cap for closing the toe opening.

6. 2. The iron-type golf club of claim 1, wherein the front surface of the intermediate sandwich layer protrudes toward the striking face portion and is compressed to define a contact width between 20% and 75% of the intermediate sandwich layer width.

7. 7. The iron-type golf club of claim 6, wherein the front surface has a radius of curvature between 10 mm and 50 mm.

8. The intermediate sandwich layer has a thickness of 0.9 g / cm ３ 2. The iron-type golf club according to claim 1, which is formed from a material having a density less than 100% and an elasticity greater than 50%.

9. 2. The iron-type golf club of claim 1, wherein the intermediate sandwich layer is formed from a first portion adjacent the face center and having a first hardness, a second portion in a toe portion of the intermediate sandwich layer and having a second hardness less than the first hardness, and a third portion in a heel portion of the intermediate sandwich layer and having a third hardness less than the first hardness.

10. At least the second and third portions are foamed to a density of 0.9 g / cm ３ 10. The iron-type golf club according to claim 9, having a density of less than 100%.

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