Golf club head with a supported striking face

Abstract

To solve the problem in which, although the utilization of a multi-material golf club head has been around, the industry has always been perplexed by the utilization of the multi-material around a striking face portion of the golf clubhead because of a large stress in impacting a golf ball; and to provide a golf club head having a multi-layered, multi-material striking face of the golf club head to further improve the performance of the golf club head.SOLUTION: A golf club head 100 having a supported striking face 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 126 juxtaposed between the striking face and the internal support layer.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This invention generally relates to a golf club head having a polymer-supported striking face. More specifically, a golf club head according to this invention further includes a striking face portion, an internal support layer, and an intermediate sandwich layer juxtaposed between the striking face portion and the internal support layer.

Background Art

[0002] Modern golf club design has evolved from the dawn of golf. The good news for all technological advancements in golf club technology is that the game of golf has become easier for golfers of all skill levels. However, all of these advancements come with significant challenges for golf club engineers.

[0003] One of the latest trends in golf club design is to utilize multiple different materials in the same golf club head, taking advantage of the individual performance characteristics of the base materials and combining them to create a golf club head with superior performance. U.S. Patent No. 5,316,298 (Hutin et al.) discloses a club head having a front striking face with a vibration damper on the back. The vibration damper includes a restraint layer connected to the back 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 polymer material to isolate the face layer from the iron body.

[0005] Although the use of multi-material golf club heads has been practiced, it should be noted that the industry has always been troubled because using multi-materials around the striking face portion of the golf club head causes significant stress when hitting a golf ball. This invention focuses on a golf club head having a multi-layer, multi-material striking face of the golf club head to further improve the performance of the golf club head.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

[0007] One aspect of the present invention is an iron-type golf club having a golf club head, a grip, and a shaft therebetween, wherein the golf club head has improved COR and feel. The golf club head is preferably composed of a striking face portion positioned at the front portion and a rear body portion attached to the striking face portion and forming a cavity therebetween. The golf club head includes a topline, a sole, a toe portion, a heel portion, and a hosel. In the present 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 has an internal support layer positioned in the cavity and connected to the rear body portion, and an intermediate sandwich layer juxtaposed between the striking face portion and the internal support layer. The intermediate sandwich layer is preferably composed of a polymer material having a sandwich face layer hardness of less than 75 Shore A and having a thickness of 1 mm and 10 mm at the face center. In an embodiment of the present invention, the internal support layer abuts the intermediate sandwich layer only between 25% and 75% thereof. Further, the intermediate sandwich layer preferably abuts a substantial amount, preferably between 90% and 100%, of the striking face portion. Most preferably, the internal 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, the intermediate sandwich layer is supported by the peripheral portion, but a substantial portion is not supported by the internal support layer. In one embodiment, the peripheral support portion has a topline width W TL that is between 2 mm and 5 mm, and a sole width W S that is between 6 mm and 20 mm adjacent to the sole. Preferably, the sole width W S is at least 1.5 times greater than the topline width W TL .

[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, wherein the golf club head has improved COR and feel. The golf club head preferably comprises a positioning strike face portion at the front portion and a rear body portion attached to the strike face portion and forming a cavity therebetween. The golf club head comprises a topline, a sole, a toe portion, a heel portion, and a hosel. In the present invention, the strike face portion preferably has a thickness between 0.6 mm and 2.4 mm at the face center. This iron-type golf club head further has an internal support layer positioned in the cavity and connected to the rear body portion, and an intermediate sandwich layer juxtaposed between the strike face portion and the internal support layer. The intermediate sandwich layer preferably consists of a polymer material, which has a sandwich face layer hardness of less than 75 Shore A and a thickness of 1 mm to 10 mm at the face center. The internal support layer abuts the intermediate sandwich layer only between 25% and 75% thereof, and also has a peripheral support portion surrounding the cavity in the golf club head and a horizontal support section extending from the heel section of the peripheral support portion to the 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 and is provided with. Further, the horizontal support section may have a closer central portion to the strike face portion such that the intermediate sandwich layer has a face center thickness 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 internal support layer abuts the intermediate sandwich layer only between 25% and 75% thereof, and also has a peripheral support portion surrounding the cavity in the golf club head and a vertical support portion extending from the topline section of the peripheral support portion to the sole portion of the peripheral support portion. Preferably, the vertical support section has a vertical support width W between 8 mm and 15 mmV It comprises. Further, the vertical support section may comprise a central portion closer to the striking face portion such that the middle sandwich layer has a face center thickness that is between 80% and 40% of the middle sandwich layer thickness closer to the topline, sole, toe portion, or heel portion.

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

[0011] In a preferred embodiment of this invention, the striking face portion of the golf club head is very thin, and more specifically, has a thickness of 1.4 mm to 1.8 mm at the face center. Further, the middle sandwich layer preferably has a thickness of 4 mm to 7 mm at the face center. Thus, the middle sandwich layer has a thickness that exceeds twice the thickness of the striking face portion.

[0012] Still other preferred embodiments of the present invention are iron-type golf clubs 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 consists of a golf club head, a grip, and a shaft therebetween. Preferably, the head has a striking face portion positioned at a front portion of the golf club head, and a rear body portion attached to the striking face portion and forming a cavity therebetween and forming a topline, a sole, a toe portion, a heel portion, and a hosel. Preferably, the striking face surface portion has a face center and has a thickness between 0.8 mm and 2.4 mm at the face center. Further, an internal support layer is connected to the rear body portion such that it is positioned within the cavity and has a front facing front surface, and an intermediate sandwich layer is juxtaposed between the striking face portion and the internal support layer. Preferably, the intermediate sandwich layer has a thickness between 1 mm and 10 mm at the face center and is composed of a polymeric material having a sandwich face layer tensile strength between 4 MPa and 20 MPa. Preferably, the internal support layer has a thermoplastic material having a support layer tensile strength between 60 MPa and 300 MPa and has a peripheral support portion surrounding the cavity. Preferably, the peripheral support portion has a peripheral width between 2 mm and 20 mm and a thickness between 0.5 mm and 5 mm. Most preferably, the striking face portion has a rear surface, the front surface of the intermediate sandwich layer abuts the rear surface of the striking face portion between 90% and 100% thereof, and at the same time, the internal support layer only abuts the intermediate sandwich layer between 25% and 75% thereof. In one embodiment, the internal support layer further has 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 that is at least 10% greater than the peripheral width. In an alternative embodiment, the internal support layer further has a vertical support section extending from a topline section of the peripheral support portion to a 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 present invention, as shown in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the present invention and enable those skilled in the relevant art to practice and use the present invention.

[0014]

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[0015] The following detailed description describes the presently contemplated best mode of carrying out the invention. This description is not to be construed as limiting the invention, but is provided for the sole purpose of explaining the general principles of the invention. The scope of the invention is most preferably defined by the appended claims. The various features of the invention are described below and can be used independently of each other or in combination with other features.

[0016] Figures 1 - 4 of the accompanying drawings show a golf club head 100 according to an exemplary embodiment of the present invention. Shown herein, the golf club head 100 has a rear body portion, i.e., a 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 consists of an internal 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 with respect to the body portion 102. The peripheral support portion further surrounds a hollow central portion 108.

[0017] The striking face portion 110 shown in FIG. 2 includes a front face portion 124, a folded-back portion 125, and a face center FC. Further, FIG. 2 shows that the striking face portion 110 may be formed as a face cup so as to form a leading edge LE and include a toe portion 115, a topline portion 113, and a sole portion 117 that are respectively coupled to the toe portion 114, the topline portion 112, and the sole portion 116 of the body portion. When the striking face portion 110 is coupled 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 internal face support 104.

[0018] FIG. 3 shows an intermediate sandwich layer 126 sandwiched in the cavity between the back surface of the front face portion 124 and the internal face support 104. The intermediate sandwich layer 126 includes 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 by the internal face support 104 around its perimeter. That is, the intermediate sandwich layer 126 is supported by an internal face support peripheral support portion 106 near the topline portion 112, the toe portion 114, the sole portion 116, and the heel portion 118. However, the internal face support 104 includes a hollow central portion 108, which does not support the intermediate sandwich layer 126 like the peripheral support portion 106. Preferably, the central portion 108 circumscribes the projection of the face center FC and allows the face center FC of the external front face portion 124 to flex during impact to improve the overall face COR of the striking face.

[0019] The external front face portion 124 is preferably formed of steel and is disposed on the external front portion of the striking face portion 110. The external front face portion 124 comprises a substantially flat striking outer surface 132 including a plurality of grooves (not shown). More preferably, the external front face portion 124 is formed of high-strength steel having an ultimate tensile strength exceeding 2000 MPa, more preferably exceeding 2300 MPa. Most preferably, the external front face portion 124 is formed from AerMet340 or the like. Further, the external front face portion 124 preferably has a uniform thickness of from about 0.6 mm to about 2.4 mm. Most preferably, the external front face portion 124 has a uniform thickness of from about 1.4 mm to about 1.8 mm. This thin external front face portion 124 and its high strength assist in creating a large COR for the golf club head 100.

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

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

[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, when measured in accordance with ASTM D412. The intermediate sandwich layer 126 may be pre-formed and inserted into the cavity or injection molded into the cavity between the back surface of the front face portion 124 and the inner face support 104. The external front face portion, of the intermediate sandwich layer 126 due to its very low tensile strength, flexes upon impact to assist in creating a hitting face portion with a very high COR. Further, to ensure that the striking face portion does not become too heavy, the polymer preferably has a specific gravity 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 composed of a silicone material, and more preferably, is composed of a silicone rubber such as SH9151U sold by KCC Silicone. Further, the intermediate sandwich layer 126 preferably has a substantially uniform thickness between about 1 mm and 10 mm, more preferably between about 3 mm and 7 mm. Also, the intermediate sandwich layer 126 preferably has a thickness at least twice that of the external front face portion at the face center FC.

[0023] As described above, the intermediate sandwich layer 126 is supported by the inner face support peripheral support portion 106 near the topline portion 112, the toe portion 114, the sole portion 116, and the heel portion 118. The peripheral support portion 106 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion 106 has a first topline width W between about 2 mm and 5 mm adjacent to the topline portion 112 TL and a second sole width W between about 6 mm and 20 mm adjacent to the sole portion 116 S and this is the first width W TLAt least 1.5 times larger than. Further, the internal face support 104 comprises a hollow central portion 108 that does not support the intermediate sandwich layer 126, and this intermediate sandwich layer 126 covers 90% to 100% of the back of the front face portion 124, but only abuts between 25% and 75% on the back of the intermediate sandwich layer. Thus, the front face portion 124 is substantially cushioned by the intermediate sandwich layer 126, but 75% to 25% of the intermediate sandwich layer 126 is not constrained by the internal face support 104. Preferably, the central portion 108 surrounds the face center FC projection, whereby the face center FC of the external front face portion 124 deflects during impact and the COR of the entire striking face is improved.

[0024] Figure 5 shows an alternative embodiment of the body disclosed in Figure 1 and discloses another embodiment. This can be used with the striking face portion 110 and the intermediate sandwich layer 126 described above with reference to Figures 2 and 3 respectively. The golf club head 200 shown here comprises a rear body portion or body portion 202 including a topline portion 212, a toe portion 214, a sole portion 216, a heel portion 218, and a hosel 220. The body portion 202 has an internal 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 portion 202 to be rigid with respect to the body portion 202. The peripheral support portion 206 further surrounds the hollow central portion 208. This embodiment further comprises a vertical support portion 222, which divides the hollow central portion 208 into a hollow toe-side portion 208a and a hollow heel-side 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 peripheral support portion 206 of the inner 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 inner face support 204 behind the face center FC. The peripheral support portion 206 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion has a first topline width W of about 2 mm to 5 mm adjacent to the topline portion 212 TL and a second sole width W of about 6 mm to 20 mm adjacent to the sole portion 216 S and the second sole width W S is at least 1.5 times the first topline width W TL . Further, the inner face support 204 has hollow central portions 208a and 208b that do not support the intermediate sandwich layer 126, and this inner face support 204 abuts between 25% and 75% of the back surface of the intermediate sandwich layer 126, whereby 75% to 25% of the intermediate sandwich layer 126 is unconstrained. In this embodiment, the vertical support portion 222 has a vertical support length L V and a vertical support width W V . The vertical support length L V is measured from the topline section of the peripheral support portion 206 to the sole section of the peripheral 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 between about 30% and 70% of the vertical support length L V . Thus, the COR of the hitting face portion 110 at the face center FC can be controlled to be similar to the COR at 1 / 2 inch from the face center FC toward the toe and at 1 / 2 inch from the face center FC toward the heel.

[0026] Figure 6 discloses an alternative embodiment of the body disclosed in Figure 1, which can be used with the striking face portion 110 and the intermediate sandwich layer 126 as described above with reference to Figures 2 and 3 respectively. The golf club head 300 shown herein has a rear body portion or body portion 302 that includes a topline portion 312, a toe portion 314, a sole portion 316, a heel portion 318, and a hosel 320. The body portion 302 is further composed of an internal face support 304 that includes a peripheral support portion 306 and a central portion 308. The peripheral support portion 306 is solid steel and is preferably cast with the body portion 302 to have rigidity with respect to the body portion. The peripheral 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 peripheral 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 behind the face center FC. The peripheral support portion 306 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion has a first topline width W between about 2 mm and 5 mm adjacent to the topline portion 312 TL and a second sole width W between about 6 mm and 20 mm adjacent to the sole portion 316 S and the second sole width W S is the first topline width W TLis at least 1.5 times that of. Further, the internal face support 304 has hollow central portions 308a and 308b that do not support the intermediate sandwich layer 126. This internal face support 304 is adjacent between 25% and 75% of the back surface of the intermediate sandwich layer 126, such that 75% to 25% of the intermediate sandwich layer 126 is not constrained. In this embodiment, the horizontal support portion 322 has a horizontal support length L H and a horizontal support width W H . The horizontal support length L H is measured from the heel portion of the peripheral support portion 306 to the toe portion of the peripheral support portion 306. Preferably, the horizontal support length L H is between about 40 mm and 80 mm, and the horizontal support width W H is between about 5 mm and 10 mm. Most preferably, the horizontal support width W H is between about 5% and 25% of the horizontal support length L H . Thereby, the COR of the hitting face portion 110 at the face center FC can be controlled over the entire hitting face portion 110, and a solid feeling can be realized.

[0028] Figures 7 and 8 of the accompanying drawings show a golf club head 400 according to an exemplary embodiment of the present invention. The shown golf club head 400 has a rear body portion or 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 preferably joined by welding or integrally casting to the body portion 402, with a cavity formed therebetween. The golf club head 400 further has an internal face support 404 including a peripheral support portion 406 and a central portion 408. The peripheral support portion 406 is preferably a thermoplastic insert disposed within the body portion 402 so as to be rigid with respect to the body portion 402. The peripheral support portion 406 further surrounds a hollow central portion 408. This embodiment further has a vertical support portion 422 that divides the hollow central portion 408 into a hollow toe-side portion 408a and a hollow heel-side portion 408b.

[0029] The striking face portion 410 shown in FIG. 7 includes a front face portion 424 having a face center. The front face portion 424 may be formed as a face cup, thus forming a leading edge LE and having a toe portion, a topline portion, and a sole portion that are preferably joined to the toe portion 414, the topline portion 412, and the sole portion 416 of the body portion, respectively, preferably by welding. The external front face portion 424 is preferably formed of steel and is positioned on the external front portion of the striking face portion 410. The external front face portion 424 has a substantially flat striking outer surface 432 that includes a plurality of grooves (not shown). More preferably, the external front face portion 424 is formed of high-strength steel having an ultimate tensile strength exceeding 2000 MPa, more preferably exceeding 2300 MPa. Most preferably, the external front face portion 424 is formed from AerMet340 or the like. Further, the external front face portion 424 preferably has a uniform thickness of from about 0.6 mm to about 2.4 mm. Most preferably, the external front face portion 424 has a uniform thickness of from about 1.4 mm to about 1.8 mm. This thin external front face portion 424 and its high strength assist in producing a high COR for the golf club head 400. Alternatively, the striking face portion 410 may be integrally cast of steel in the same manner as the body portion 402.

[0030] An intermediate sandwich layer, such as intermediate sandwich layer 426 shown in FIG. 4, is sandwiched within a cavity between the back surface of front face portion 424 and inner face support 404. Intermediate sandwich layer 426 has a front facing surface 425 that is substantially the same area as the back surface of front face portion 424. Preferably, intermediate sandwich layer 426 is supported around its perimeter by inner face support 404. That is, intermediate sandwich layer 426 is supported by inner face support perimeter support portion 406 near topline portion 412, toe portion 414, sole portion 416, and heel portion 418. However, inner face support 404 includes a hollow central portion 408 that does not support intermediate sandwich layer 426 as does perimeter support portion 406, such that intermediate sandwich layer 426 is at least partially unrestrained.

[0031] Inner face support 404 is fixed within internal hollow portion 429 of golf club head 400. Inner face support 404 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 between about 2000 MPa and 8000 MPa. Preferably, inner face support 404 has a thickness between about 0.5 mm and 5 mm, more preferably between about 0.8 mm and 2 mm.

[0032] As described above, intermediate sandwich layer 426 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, when measured in accordance with ASTM D412. of the intermediate sandwich layer 426Due to the very low tensile strength, the external face portion can flex during impact, which helps create an impact face portion with a very high COR. Further, to ensure that the impact face portion does not become too heavy, the polymer preferably has a specific gravity 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 composed of a silicone material, and more preferably, it is composed of a silicone rubber such as SH9151U sold by KCC Silicone Corporation. Further, the intermediate sandwich layer 426 preferably has a substantially uniform thickness between about 1 mm and 10 mm, more preferably between about 3 mm and 7 mm. The intermediate sandwich layer 426 also preferably has a thickness at least twice that of the external front face portion at the face center FC.

[0033] As described 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 top line width W of about 2 mm to 5 mm adjacent to the top line portion 412 TL and a second sole width W of about 6 mm to 20 mm adjacent to the sole portion 416 S and this is at least 1.5 times the first width W TL Furthermore, the internal face support 404 has a hollow central portion 408 that does not support the intermediate sandwich layer 426 and only abuts between 25% and 75% of the back surface of the intermediate sandwich layer. On the other hand, the intermediate sandwich layer 426 covers between 90% and 100% of the back surface of the external front face portion 424. Thus, the external front face portion 424 is substantially attenuated by the intermediate sandwich layer 426, but 75% to 25% of the intermediate sandwich layer 426 is not constrained by the internal face support 404. In this embodiment, the vertical support portion 422 has a vertical support length L V and a vertical support width W V and the vertical support length L Vis measured from the topline section of the peripheral support portion 406 to the sole section of the peripheral 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 between about 30% and 70% of the vertical support length L V In this way, the COR of the hitting face portion 410 at the face center FC can be controlled to be the same as the COR at 1 / 2 inch from the face center FC toward the toe and at 1 / 2 inch from the face center FC toward the heel.

[0034] FIG. 9 of the accompanying drawings shows a golf club head body portion 502 that can be combined with the hitting face portion 110 disclosed in FIG. 2. According to an exemplary embodiment of this 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 has a hitting face portion 110, which is preferably joined to the body portion 502 by welding or integrally casting, forming a cavity therebetween. The golf club head further has an internal face support 504 including a peripheral support portion 506 and a central portion 508. The peripheral support portion 506 is preferably a thermoplastic insert disposed within the body portion 502 and thus has rigidity with respect to the body portion 502. The peripheral support portion 506 further surrounds a hollow central portion 508. This embodiment further has a horizontal support portion 522 that divides the hollow central portion 508 into a hollow toe-side portion 508a and a hollow heel-side portion 508b.

[0035] Similar to 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 having a toe portion 514, a topline portion 512, and a sole portion 516 of the body portion, respectively, preferably joined by welding. The external front face portion 124 is preferably formed of steel and is positioned on the external front portion of the striking face portion 110. The external front face portion 124 has a substantially flat striking outer surface, which includes a plurality of grooves (not shown). More preferably, the external front face portion 124 is formed of high-strength steel having an ultimate tensile strength exceeding 2000 MPa, more preferably exceeding 2300 MPa. Most preferably, the external front face portion 124 is formed from AerMet340 or the like. Further, the external front face portion 124 preferably has a uniform thickness of from about 0.6 mm to about 2.4 mm. Most preferably, the external front face portion 124 has a uniform thickness of from about 1.4 mm to about 1.8 mm. This thin external front face portion 124 and its high strength assist in producing a high COR for the golf club head. Alternatively, the striking face portion 110 may be integrally cast with the body portion 102 and formed of 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 back surface of the front face portion 124 and the inner face support 504. The intermediate sandwich layer 126 has a front facing surface 127 that is substantially the same area as the back surface of the front face portion 124. Preferably, the intermediate sandwich layer 126 is supported by the inner face support 504 around its perimeter. That is, the intermediate sandwich layer 126 is supported by the inner face support peripheral support portion 506 near the topline portion 512, the toe portion 514, and the sole portion. However, the inner face support 504 has a hollow central portion 508 that does not support the intermediate sandwich layer 126 like the support portion 506 so that the intermediate sandwich layer 126 is not at least partially constrained.

[0037] The inner face support 504 is fixed to the internal 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 between about 0.5 mm and 5 mm, more preferably between about 0.8 mm and 2 mm.

[0038] As described above, 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, when measured in accordance with ASTM D412. of the intermediate sandwich layer 126Due to the very low tensile strength, the external front face portion can flex during impact, assisting in creating a striking face portion with a very high COR. Further, to ensure that the striking face portion does not become 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 composed of a silicone material, and more preferably, it is composed of a silicone rubber such as SH9151U sold by KCC Silicone Corporation. Further, the intermediate sandwich layer 126 preferably has a substantially uniform thickness of about 1 mm to 10 mm, and more preferably, this is between about 3 mm and 7 mm. Also, the intermediate sandwich layer 126 preferably has a thickness at least twice that of the external front face portion at the face center FC.

[0039] As described 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 top line width W of about 2 mm to 5 mm adjacent to the top line portion 512 TL and a second sole width W of about 6 mm to 20 mm adjacent to the sole portion 516 S and has a second sole width W S which is at least 1.5 times the first width W TL Furthermore, the internal face support 504 has a hollow central portion 508 that does not support the intermediate sandwich layer 126, and only abuts 25% to 75% of the back of the intermediate sandwich layer 126, yet covers 90% to 100% of the intermediate sandwich layer 126. Thus, the external front face portion 124 is substantially damped and supported by the intermediate sandwich layer 126, but 75% to 25% of the intermediate sandwich layer 126 is not constrained by the internal face support 504. In this embodiment, the horizontal support portion 522 has a horizontal support length L H and a horizontal support width W H and has a horizontal support length L His measured from the heel portion of the peripheral support portion 506 to the toe portion of the peripheral support portion 506. Preferably, the horizontal support length L H is between about 40 mm and 80 mm, and the horizontal support width W H is between about 5 mm and 10 mm. Most preferably, the horizontal support width W H is between about 5% and 25% of the horizontal support length L H . Thereby, the COR of the hitting face portion 110 at the face center FC can be controlled over the entire hitting face portion 110, and a solid feeling can be realized.

[0040] Figures 10 and 11 disclose alternative embodiments of the golf club head body disclosed in FIG. 5, which, as described above with reference to FIGS. 2 and 3 respectively, can be exchanged for the body portion 202 and used with the hitting face portion 110 and the intermediate sandwich layer 126, which is the same as described above. The golf club head 600 shown here comprises a rear body portion or body portion 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 including a peripheral support portion 606 and a central portion 608. The peripheral support portion 606 is solid steel and is preferably cast with the body portion 602 to be rigid with respect to the body portion 602. The peripheral support portion 606 further surrounds a hollow central portion 608. This embodiment further comprises a vertical support portion 622, which divides the hollow central portion 608 into a hollow toe-side portion 608a and a hollow heel-side 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 peripheral support portion 606 of the inner 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 inner face support 604 behind the face center FC. The peripheral support portion 606 preferably has a width between about 2 mm and 20 mm. More preferably, the peripheral support portion has a first topline width W of about 2 mm to 5 mm adjacent to the topline portion 612 TL and a second sole width W of about 6 mm to 20 mm adjacent to the sole portion 616 S and the second sole width W S is at least 1.5 times the first topline width W TL . Further, the inner face support 604 has hollow central portions 608a and 608b that do not support the intermediate sandwich layer 126, and the inner face support 604 abuts the back of the intermediate sandwich layer 126 between 25% and 75% thereof, such that 75% to 25% of the intermediate sandwich layer 126 is unconstrained. In this embodiment, the vertical support portion 622 has vertical support lengths L VA , L VB , and L VC and a vertical support width W V . The vertical support lengths L VA , L VB , and L VC are measured from the topline section of the peripheral support portion 606 to the sole section of the peripheral support portion 606. Preferably, the vertical support lengths L VA , L VB , and L VC are 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 lengths L VA , L VB , and L VCis between about 30% and 70%. Thus, the COR of the hitting face portion 110 at the face center FC can be controlled to be the same as the COR at 1 / 2 inch from the face center FC toward the toe and at 1 / 2 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 hitting face portion 110, such that the intermediate sandwich layer 126 has a first thickness t P that is smaller than a second surrounding thickness t FC at the face center, surrounding the face center. As shown, the top vertical support portion 622b and the bottom vertical support portion 622c connect the central vertical portion 622 to the surrounding support portion 606, but are angled from the surrounding support portion 606 toward the hitting face portion 110. Thus, the first thickness t FC at the face center is between about 80% and 40% of a second surrounding thickness t P at 1 / 2 inch from the face center toward the toe portion 614 and the heel portion 618. Preferably, the central vertical support portion 622a has a 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 at least 20% greater than both the top vertical support length L VB and the bottom vertical support length L VC . In such a manner, the COR of the hitting face portion 110 can be kept more constant near the face center FC.

[0042] Figures 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, i.e., the 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 the striking face portion 710. The golf club head further has an internal face support 704, which includes a support bar portion 706, a central support portion 705, and a plurality of openings 708. The internal face support 704 is preferably a thermoplastic insert, which has a support layer tensile strength of 60 MPa to 300 MPa and a flexural modulus of about 2000 MPa to 8000 MPa, and is positioned within the body portion 702 to be rigid with respect to the body portion 702. The internal face support 704 is preferably coupled to the body portion 702 by abutting or snap-fitting to a plurality of lip portions 732 inside the body portion 702, or by a fastener 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 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 SB and a thickness at least 1.5 times the thickness of the central support portion 705.

[0043] An intermediate sandwich layer, such as the intermediate sandwich layer 726 shown in FIG. 7, is sandwiched within a cavity between the back surface of the striking face portion 710 and the internal face support. The intermediate sandwich layer 726 has a front opposing surface that has substantially the same area as the back surface of the striking face portion 710. Preferably, the internal face support 704 comprises a plurality of openings 708 and gaps 734 that do not support the intermediate sandwich layer 726. Accordingly, the internal face support 704 contacts the back surface of the intermediate sandwich layer only between 25% and 75% thereof, and yet the intermediate sandwich layer 726 covers between 90% and 100% of the back surface of the striking face portion 710.

[0044] As described above, the intermediate sandwich layer 726 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, when measured in accordance with ASTM D412. of the intermediate sandwich layer 726 Due to the very low tensile strength, the external front face portion can flex during impact, assisting in creating a striking face portion with a very high COR. Further, to keep the golf club head 700 from becoming 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 has a silicone material, and more preferably has a silicone rubber such as SH9151U sold by KCC Silicone Corporation. Further, the intermediate sandwich layer 726 preferably has a substantially uniform thickness of about 1 mm to 10 mm, more preferably between about 3 mm and 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] Figures 14 - 16 of the accompanying drawings show a part of the golf club head 800. According to an exemplary embodiment of the present invention, the rear body part, i.e., the body part 802, includes a toe part 814, a sole part 816, a heel part 818, and a hosel 820 that can be integrally cast with the striking face part 810. The golf club head further has an internal face support 804 including a topline part 812, a central support part 805, and a plurality of openings 808. Similar to the above, the internal face support 804 is preferably a thermoplastic insert, which has a support layer tensile strength between 60 MPa and 300 MPa and a flexural modulus between about 2000 MPa and 8000 MPa, and is arranged in the body part 802 to be rigid with respect to the body part 802. The internal face support 804 is preferably coupled to the body part 802 by abutting or snap - fitting with a plurality of lip parts 832 inside the body part 802 and ledge parts 834 of the toe part 814 and the heel part 818. Fasteners may be incorporated as required. Preferably, the central support part 805 has a thickness between about 0.5 mm and 5 mm, more preferably between about 0.8 mm and 2 mm.

[0046] An intermediate sandwich layer, such as the intermediate sandwich layer 726 shown in FIG. 12, is preferably sandwiched in a cavity between the back surface of the striking face part 810 and the internal face support 804. Preferably, the internal face support 804 has a plurality of openings 808 that do not support the intermediate sandwich layer 726. The internal face support 804 preferably abuts only 25% to 75% of the back surface of the intermediate sandwich layer, while the intermediate sandwich layer 726 covers 90% to 100% of the back surface of the striking face part 810.

[0047] Except for the operation examples, or unless otherwise specified, all numerical ranges, amounts, values, and percentages such as the amount of materials, moment of inertia, center of gravity position, loft, draft angle, various performance ratios, and others in the previous part of this specification should be understood as if the term "about" were prefixed, even if the term "about" does not explicitly appear in the value, amount, or range. Therefore, unless otherwise indicated, the numerical parameters described in the above specification and the appended claims are approximate values that can vary depending on the desired characteristics required to be obtained by this invention. At least, without attempting to limit the scope of the application of the doctrine of equivalents, each numerical parameter should be interpreted by applying ordinary rounding methods in light of at least the reported significant digits.

[0048] Despite the fact that the numerical ranges and parameters indicating the broad scope of this invention are approximate values, the numerical values shown in specific examples are reported as accurately as possible. However, the numerical values inherently include certain errors due to the standard deviations found in each test measurement. Furthermore, it should be noted that when various ranges of numerical ranges are described herein, any combination of these values including the listed values can be used.

[0049] Of course, it should be understood that the foregoing description relates to exemplary embodiments of this invention and that modifications can be made without departing from the spirit and scope of this invention as described in the following claims. The following lists the technical features described herein. [Technical Feature 1] In an iron-type golf club, the golf club has a golf club head, a grip, and a shaft therebetween, the golf club head is a striking face portion positioned at the front portion of the golf club head, the striking face portion having a striking face portion center, a rear surface of the striking face portion, and a thickness at the striking face portion center between 0.6 mm and 2.4 mm; and a rear body portion coupled to the striking face portion, forming a cavity therebetween, and forming a topline portion, a sole portion, a toe portion, a heel portion, and a hosel; and an internal support layer positioned within the cavity and coupled to the rear body portion, the internal support layer having a front surface of the internal support layer; and an intermediate sandwich layer juxtaposed between the striking face portion and the internal support layer, the intermediate sandwich layer having a sandwich face layer hardness of less than 75 Shore A, having a thickness from 1 mm to 10 mm at the face center, and having a front surface of the intermediate sandwich layer and a rear surface of the intermediate sandwich layer; and the front surface of the internal support layer abuts the rear surface of the intermediate sandwich layer between 25% and 75% thereof, an iron-type golf club characterized thereby. [Technical Feature 2] The golf club according to Technical Feature 1, wherein the front surface of the intermediate sandwich layer abuts the rear surface of the striking face portion between 90% and 100% thereof. [Technical Feature 3] The golf club according to Technical Feature 1, wherein the internal support layer surrounds the cavity and has a surrounding support portion having a width between 2 mm and 20 mm and a thickness between 0.5 mm and 5 mm. [Technical Feature 4] The golf club according to Technical Feature 3, wherein the internal support layer further has a horizontal support section extending from a heel section of the surrounding support portion to a toe section of the surrounding support portion. [Technical Feature 5] The golf club according to Technical Feature 3, wherein the inner support layer further has a vertical support section extending from the topline section of the peripheral support portion to the sole section of the peripheral support portion. [Technical Feature 6] The golf club according to Technical Feature 3, wherein the inner support layer is made of steel and is integrally cast with the rear body portion. [Technical Feature 7] The golf club according to Technical Feature 3, wherein the inner support layer is made of a thermoplastic material having an inner support layer tensile strength at least 10 times greater than the intermediate sandwich layer tensile strength. [Technical Feature 8] The golf club according to Technical Feature 1, wherein the striking face portion has a thickness between 1.4 mm and 1.8 mm at the face center. [Technical Feature 9] The golf club according to Technical Feature 1, wherein the intermediate sandwich layer has a thickness between 4 mm and 7 mm at the face center. [Technical Feature 10] The golf club according to Technical Feature 3, wherein the peripheral support portion has a topline width W between 2 mm and 5 mm adjacent to the topline portion, TL and a sole width W between 6 mm and 20 mm adjacent to the sole portion. S [Technical Feature 11] The golf club according to Technical Feature 10, wherein the sole width W S is at least 1.5 times the topline width W. TL [Technical Feature 12] The golf club according to Technical Feature 4, wherein the horizontal support section has a horizontal support width W between 5 mm and 10 mm. H [Technical Feature 13] The golf club according to Technical Feature 5, wherein the vertical support section has a vertical support width W between 8 mm and 15 mm. V [Technical Feature 14] The golf club according to Technical Feature 13, wherein the vertical support section is closer to the striking face portion, and thus the intermediate sandwich layer has a face center thickness between 80% and 40% of the intermediate sandwich layer thickness closer to the toe portion. [Technical Feature 15] The golf club according to Technical Feature 13, wherein the vertical support section has a central portion closer to the striking face portion, and thus the intermediate sandwich layer has a thickness between 80% and 40% of the intermediate sandwich layer thickness closer to the heel portion at the face center. [Technical Feature 16] In an iron-type golf club, The golf club has a golf club head, a grip, and a shaft therebetween, The golf club head is, a striking face portion positioned at a front face portion of the golf club head, the striking face portion having a face center and a thickness at the face center between 0.8 mm and 2.4 mm, a rear body portion coupled to the striking face portion, forming a cavity therebetween, and forming a topline portion, a sole portion, a toe portion, a heel portion, and a hosel, an internal support layer, the internal support layer being coupled to the rear body portion such that the internal support layer is positioned within the cavity and has a front opposing front surface, an intermediate sandwich layer juxtaposed between the striking face portion and the internal support layer, the intermediate sandwich layer having a thickness between 1 mm and 10 mm at the face center, having a rear surface and a front surface of the intermediate sandwich layer, and being made of a polymer material having a sandwich face layer tensile strength between 4 MPa and 20 MPa, The internal support layer has a thermoplastic material having a support layer tensile strength between 60 MPa and 300 MPa, the internal support layer surrounding the cavity and having a surrounding thickness between 2 mm and 20 mm and a surrounding support portion having a thickness between 0.5 mm and 5 mm, and being characterized by an iron-type golf club. [Technical Feature 17] The golf club according to Technical Feature 16, wherein the striking face portion has a rear surface, and the front surface of the intermediate sandwich layer abuts against the rear surface of the striking face portion between 90% and 100%. [Technical Feature 18] The golf club according to Technical Feature 16, wherein the internal support layer further has a horizontal support section extending from a heel section of the surrounding support portion to a toe section of the surrounding support portion. [Technical Feature 19] The golf club according to Technical Feature 18, wherein the horizontal support section has a horizontal support width that is at least 10% wider than the surrounding width. [Technical Feature 20] The golf club according to Technical Feature 16, wherein the internal support layer further has a vertical support section extending from a topline section of the surrounding support portion to a sole section of the surrounding support portion. [Technical Feature 21] The golf club as described in Technical Feature 16, wherein the tensile strength of the support layer is at least 10 times greater than the tensile strength of the sandwich face layer. [Description of Signs] 100 Golf club head 102 Body part 104 Inner face support 106 Peripheral support part 108 Hollow central part 110 Impact face part 112 Top line part 113 Top line part 114 Toe part 115 Toe part 116 Sole part 117 Sole part 118 Heel part 120 Hosel 124 Outer front face part 125 Folded-back part 126 Intermediate sandwich layer 127 Front-facing surface 129 Inner hollow part 132 Impact outer surface 200 Golf club head 202 Body part 204 Inner face support 206 Peripheral support part 208 Hollow central part 212 Top line part 214 Toe part 216 Sole part 218 Heel part 220 Hosel 222 Vertical support part 300 Golf club head 302 Body part 304 Inner face support 306 Peripheral support part 308 Hollow central part 312 Top line part 314 Toe part 316 Sole part 318 Heel part 320 Hosel 322 Horizontal support part 400 Golf club head 402 Body part 404 Inner face support 406 Peripheral support part 408 Hollow central part 410 Impact face part 412 Top line part 414 Toe part 416 Sole part 418 Heel part 420 Hosel 422 Vertical support part 424 Outer front face part 425 Front-facing surface 426 Intermediate sandwich layer 429 Inner hollow part 432 Impact outer surface 502 Body part 504 Inner face support 506 Peripheral support part 508 Hollow central part 512 Top line part 514 Toe part 516 Sole part 518 Heel part 520 Hosel 522 Horizontal support part 600 Golf club head 602 Body part 604 Inner face support 606 Peripheral support part 608 Hollow central part 612 Top line part 614 Toe part 616 Sole part 618 Heel part 620 Hosel 622 Vertical support part 700 Golf club head 702 Body part 704 Inner face support 705 Central support part 706 Support bar part 708 Opening 710 Impact face part 712 Topline portion 714 Toe portion 716 Sole portion 718 Heel portion 720 Hosel 726 Intermediate sandwich layer 730 Fastener 732 Lip portion 734 Gap 800 Golf club head 802 Body portion 804 Internal face support 805 Central support portion 808 Opening 810 Striking face portion 812 Topline portion 814 Toe portion 816 Sole portion 818 Heel portion 820 Hosel 832 Lip portion 834 Ledger portion

Claims

**Claim 1** In an iron-type golf club, the golf club has a golf club head, a grip, and a shaft therebetween, the golf club head includes a striking face portion positioned at the front face portion of the golf club head, the striking face portion having a striking face portion face center, a rear surface of the striking face portion, and a thickness at the striking face portion face center between 0.6 mm and 2.4 mm; a rear body portion coupled to the striking face portion, forming a cavity therebetween, and forming a topline portion, a sole portion, a toe portion, a heel portion, and a hosel; an internal support layer positioned within the cavity and coupled to the rear body portion, the internal support layer having a front surface of the internal support layer; a middle sandwich layer juxtaposed between the striking face portion and the internal support layer, the middle sandwich layer having a sandwich face layer hardness of less than 75 Shore A, having a thickness of 1 mm to 10 mm at the striking face portion face center, and having a front surface of the middle sandwich layer and a rear surface of the middle sandwich layer; and the front surface of the internal support layer abuts the rear surface of the middle sandwich layer between 25% and 75% thereof, wherein the internal support layer has a tensile strength of 400 MPa or more, and the middle sandwich layer has a tensile strength of 4 MPa to 20 MPa. An iron-type golf club characterized by this. **Claim 2** The golf club according to claim 1, wherein the front surface of the middle sandwich layer abuts the rear surface of the striking face portion between 90% and 100% thereof. **Claim 3** The golf club according to claim 1, wherein the internal support layer surrounds the cavity and has a surrounding support portion having a width between 2 mm and 20 mm and a thickness between 0.5 mm and 5 mm. **Claim 4** The golf club according to claim 3, wherein the internal support layer further has a horizontal support section extending from a heel section of the surrounding support portion to a toe section of the surrounding support portion. **Claim 5** The golf club according to claim 3, wherein the internal support layer further has a vertical support section extending from the topline section of the peripheral support portion to the sole section of the peripheral support portion.

6. The golf club according to claim 3, wherein the internal support layer is made of steel and is cast integrally with the rear body portion.

7. The golf club according to claim 3, wherein the internal support layer is made of a thermoplastic material having an internal support layer tensile strength that is at least 10 times greater than the tensile strength of the intermediate sandwich layer.

8. The golf club according to claim 1, wherein the striking face portion has a thickness between 1.4 mm and 1.8 mm at the center of the striking face portion face.

9. The golf club according to claim 1, wherein the intermediate sandwich layer has a thickness between 4 mm and 7 mm at the center of the striking face portion face.

10. The above-mentioned peripheral support portion has a topline width W between 2 mm and 5 mm adjacent to the above-mentioned topline portion ＴＬ , and a sole width W between 6 mm and 20 mm adjacent to the above-mentioned sole portion Ｓ The golf club according to claim 3, comprising

11. The above sole width W Ｓ is at least 1.5 times the above topline width W ＴＬ The golf club according to claim 10

12. The golf club according to claim 4, wherein the horizontal support section has a horizontal support width W between 5 mm and 10 mm. Ｈ ​

13. The vertical support section has a vertical support width W between 8 mm and 15 mm Ｖ The golf club according to claim 5, comprising the same

14. The golf club according to claim 13, wherein the vertical support section has a central portion closer to the striking face portion, whereby the intermediate sandwich layer has a thickness at the center of the striking face portion face between 80% and 40% of the thickness of the intermediate sandwich layer closer to the toe portion.

15. The golf club according to claim 13, wherein the vertical support section has a central portion closer to the striking face portion, whereby the intermediate sandwich layer has a first thickness at the center of the striking face portion face between 80% and 40% of the thickness of the intermediate sandwich layer closer to the heel portion.

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