Golf club head with a supportive striking face

Abstract

To provide a golf club head having a multi-layered, multi-material striking face of a golf club head to further improve the performance of a golf club head.SOLUTION: A golf club head 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 juxtaposed between the striking face and the internal support layer. The internal support layer comprises: a perimeter support portion 506 surrounding a hollow center portion; and a horizontal support portion 522 that divides the hollow center portion into a hollow toe side portion 508a and a hollow heel side portion 508b. Instead of the horizontal support portion, a vertical support portion may be provided which divides the hollow center portion into a hollow toe side portion and a hollow heel side portion.SELECTED DRAWING: Figure 9

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 pose 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 to take advantage of the individual performance characteristics of the base materials and combine them to create a golf club head with better 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. 9,8,44,230 (Snyder) shows an iron body and a ball striking plate engaged with 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] While multi-material golf club heads have been used, it should be noted that the industry has always been troubled by the significant stress caused when hitting a golf ball due to the use of multiple materials around the striking face of the golf club head. This invention focuses on a golf club head equipped with a multi-layered, multi-material striking face in order to further improve the performance of golf club heads. [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 [Overview of the project]

[0007] One aspect of this invention is an iron-type golf club having a golf club head, grip, and shaft between them, wherein the golf club head has improved COR and feel. The golf club head preferably consists of a striking face portion positioned at the front and a rear body portion attached to the striking face portion and forming a cavity between them. The golf club head comprises a top line, sole, toe portion, heel portion, and hosel. In this invention, the striking face portion preferably has a thickness between 0.6 mm and 2.4 mm at the center of the face. The iron-type golf club head further comprises an internal support layer positioned within the cavity and connected to the rear body portion, and an intermediate sandwich layer positioned between the striking face portion and the internal support layer. The intermediate sandwich layer preferably consists of a polymer material having a sandwich face layer hardness of less than 75 Shore A and thicknesses of 1 mm and 10 mm at the center of the face. In embodiments of this invention, the internal support layer abuts the intermediate sandwich layer by only 25% to 75% of its extent. Furthermore, the intermediate sandwich layer preferably contacts a considerable portion of the striking face, preferably between 90% and 100% of the striking face. Most preferably, the internal support layer has a perimeter support portion, which 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, although the intermediate sandwich layer is supported by the perimeter portion, a substantial portion is not supported by the internal support layer. In one embodiment, the perimeter support portion is adjacent to the top line, with a top line width W TL The width is between 2mm and 5mm, and the sole width adjacent to the sole is W S The width is between 6mm and 20mm. Preferably, the sole width W S The top line width is W TL It is at least 1.5 times larger than that.

[0008] Another preferred embodiment of this invention is an iron-type golf club having a golf club head, a grip, and a shaft between them, wherein the golf club head has improved COR and feel. The golf club head preferably comprises a positioning striking face portion in the front part and a rear body portion attached to the striking face portion and forming a cavity between them. 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 center of the face. This iron-type golf club head further comprises an internal 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 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 has a thickness between 1 mm and 10 mm at the center of the face. The internal support layer contacts the intermediate sandwich layer for 25% to 75% of its length and has a perimeter support portion surrounding the cavity in the golf club head, and a horizontal support section extending from the heel section to the toe section of the perimeter support portion. Preferably, the horizontal support section has a horizontal support width W between 5 mm and 10 mm. H The horizontal support section may have a central portion closer to the striking face, such that the intermediate sandwich layer has a face center thickness that is between 80% and 40% of the thickness of the intermediate sandwich layer near the top line, sole, toe, or heel.

[0009] In an alternative embodiment of this invention, the internal support layer contacts the intermediate sandwich layer for only 25% to 75% of its length, and has a perimeter support portion surrounding the cavity in the golf club head, and a vertical support portion extending from the topline section of the perimeter support portion to the sole portion of the perimeter support portion. Preferably, the vertical support section has a vertical support width W between 8 mm and 15 mm.V The vertical support section may also have a central portion closer to the hitting face such that the intermediate sandwich layer has a face-center thickness that is between 80% and 40% of the thickness of the intermediate sandwich layer closer to the top line, sole, toe, or heel.

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

[0011] In a preferred embodiment of this 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 center of the face. Furthermore, the intermediate sandwich layer preferably has a thickness of 4 mm to 7 mm at the center of the face. Thus, the intermediate sandwich layer has a thickness of more than twice the thickness of the striking face portion.

[0012] A further preferred embodiment of this invention is an iron-type golf club having a golf club head, a grip, and a shaft between them, wherein the golf club head has improved COR and feel. The iron-type golf club consists of a golf club head, a grip, and a shaft between them. Preferably, the head has a striking face portion located in the front part of the golf club head, and a rear body portion attached to the striking face portion, forming a cavity between them, and forming a top line, sole, toe portion, heel portion, and hosel. Preferably, the striking face portion has a face center and has a thickness between 0.8 mm and 2.4 mm at the face center. Furthermore, 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 of 1 mm to 10 mm at the center of the face and is composed of a polymer material having a sandwich face layer tensile strength of 4 MPa to 20 MPa. Preferably, the internal support layer has a thermoplastic material having a support layer tensile strength of 60 MPa to 300 MPa and has a periphery support portion surrounding the cavity. Preferably, the periphery support portion has a periphery width of 2 mm to 20 mm and a thickness of 0.5 mm to 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 by 90% to 100%, and at the same time, the internal support layer abuts the intermediate sandwich layer by 25% to 75%. In one embodiment, the internal support layer further has a horizontal support section extending from the heel section of the periphery support portion to the toe section of the periphery support portion. Preferably, the horizontal support section has a horizontal support width at least 10% greater than the periphery width. In an alternative embodiment, the internal support layer further includes vertical support sections extending from the topline section of the periphery support portion to the sole section of the periphery support portion. [Brief explanation of the drawing]

[0013] The aforementioned and other features and advantages of this invention will become apparent from the following description of this invention, as shown in the accompanying drawings. The accompanying drawings incorporated herein and forming part of the specification further illustrate the principles of this invention and will enable those skilled in the related art to practice and use this invention.

[0014] [Figure 1] Figure 1 in the attached drawings shows a front view of the golf club head body portion according to an embodiment of this invention. [Figure 2] Figure 2 of the attached drawings shows a front view of the golf club head face cup that connects to the main body portion disclosed in Figure 1. [Figure 3] Figure 3 in the attached drawings shows the intermediate layer of the golf club head, positioned between the main body portion of Figure 1 and the face cup of Figure 2. [Figure 4] Figure 4 in the attached drawings shows a cross-sectional view of the golf club head according to Figures 1-3. [Figure 5] Figure 5 in the attached drawings shows a front view of an alternative embodiment of the golf club head body shown in Figure 1. [Figure 6] Figure 6 in the attached drawings shows a front view of an alternative embodiment of the golf club head body shown in Figure 1. [Figure 7] Figure 7 in the attached drawings shows a cross-sectional view of an alternative embodiment of a golf club head according to this invention. [Figure 8] Figure 8 in the attached drawings shows a front view of an alternative embodiment of the golf club head body shown in Figures 1 and 7. [Figure 9] Figure 9 in the attached drawings shows a front view of an alternative embodiment of the golf club head body shown in Figures 1 and 7. [Figure 10] Figure 10 of the attached drawings shows a front view of the golf club head body portion according to an alternative embodiment of the present invention shown in Figure 6. [Figure 11] Figure 11 in the attached drawings shows a cross-sectional view of a portion of the golf club head in the embodiment shown in Figure 10. [Figure 12] Figure 12 in the attached drawings shows a rear view of a golf club head according to an embodiment of this invention. [Figure 13] Figure 13 in the attached drawings shows a perspective view of the rear body portion of the golf club head shown in Figure 12. [Figure 14] Figure 14 in the attached drawings shows a cross-sectional view of the rear body portion of a golf club head according to an embodiment of this invention. [Figure 15] Figure 15 in the attached drawings shows a cross-sectional view of the internal support layer of the golf club head shown in Figure 14. [Figure 16] Figure 16 in the attached drawings shows a rear perspective view of the main body portion of the golf club head shown in Figures 14 and 15. [Modes for carrying out the invention]

[0015] The following detailed description illustrates the best currently conceivable mode of carrying out this invention. This description should not be construed as limiting the invention, but is provided solely for the purpose of illustrating the general principles of the invention. The scope of this invention is best defined by the appended claims. Various features of this invention are described below, each of which can be used independently of the others or in combination with other features.

[0016] Figures 1-4 of the attached drawings show a golf club head 100 according to an exemplary embodiment of the present invention. Shown herein is a rear body portion, 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 consists of an internal face support 104, which includes a perimeter support portion 106 and a central portion 108. The perimeter support portion 106 is made of solid steel and is preferably cast together with the body portion 102 to be rigid relative to the body portion 102. The perimeter support portion further surrounds the hollow central portion 108.

[0017] The striking face portion 110 shown in Figure 2 includes a front face portion 124, a folded portion 125, and a face center FC. Furthermore, Figure 2 shows that the striking face portion 110 may be formed as a face cup having a toe portion 115, a topline portion 113, and a sole portion 117 that form a leading edge LE and connect to the toe portion 114, topline portion 112, and sole portion 116 of the main body portion, respectively. When the striking face portion 110 is joined to the main body portion 102, preferably by welding around the striking face portion 110, the striking face portion 110 and the main body portion 102 form a cavity between the front face portion 124 and the internal face support 104.

[0018] Figure 3 shows an intermediate sandwich layer 126 sandwiched within the cavity between the back of the front face portion 124 and the internal face support 104. The intermediate sandwich layer 126 has a front opposing surface 127 that is substantially the same area as the front face portion 124. Preferably, the intermediate sandwich layer 126 is supported around its periphery by the internal face support 104. That is, the intermediate sandwich layer 126 is supported by the internal face support periphery support portion 106 near the topline portion 112, toe portion 114, sole portion 116, and heel portion 118. However, the internal face support 104 has a hollow central portion 108 that does not support the intermediate sandwich layer 126 like the periphery support portion 106. Preferably, the central portion 108 is tangent to the projection of the face center FC, allowing the face center FC of the outer front face portion 124 to flex at impact to improve the overall impact face COR.

[0019] The outer front face portion 124 is preferably made of steel and is positioned on the outer front portion of the striking face portion 110. The outer front face portion 124 comprises a substantially flat striking outer surface 132, which includes a plurality of grooves (not shown). More preferably, the outer front face portion 124 is made of high-strength steel having an ultimate tensile strength of over 2000 MPa, more preferably over 2300 MPa. Most preferably, the outer front face portion 124 is made of AerMet340 or the like. Furthermore, 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 to produce a large COR of 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 from 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 it may 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 of about 0.5 mm to 5 mm, more preferably 0.8 mm to 2 mm.

[0021] The striking face portion 110 is in contact with an intermediate sandwich layer 126 positioned between the front face portion 124 and the internal face support 104. Preferably, the intermediate sandwich layer 126 is supported around its periphery by the internal face support 104. That is, the intermediate sandwich layer 126 is supported along the topline portion, toe portion, sole portion, and heel portion. This improves the overall COR of the striking face.

[0022] The intermediate sandwich layer 126 is a polymeric material having a tensile strength in the range of from about 4 MPa to 20 MPa, more preferably from 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 outer front face portion flexes upon impact due to its very low tensile strength, assisting in creating a hitting face portion with a very high COR. Further, in order for the hitting face portion not to 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, more preferably 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 the thickness of the outer 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 TLIt is at least 1.5 times larger than the intermediate sandwich layer 126. Furthermore, the internal face support 104 comprises a hollow central portion 108 that does not support the intermediate sandwich layer 126, and although the intermediate sandwich layer 126 covers 90% to 100% of the back of the front face portion 124, it only contacts the back of the intermediate sandwich layer for 25% to 75% of the time. Thus, although the front face portion 124 is substantially buffered by the intermediate sandwich layer 126, 75% to 25% of the intermediate sandwich layer 126 is not restrained by the internal face support 104. Preferably, the central portion 108 surrounds the face center FC projection, thereby allowing the face center FC of the external front face portion 124 to flex upon impact, improving the COR of the entire striking face.

[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 herein comprises a rear body portion or body portion 202, which includes 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 perimeter support portion 206 and a central portion 208. The perimeter support portion 206 is made of solid steel and is preferably cast together with the body portion 202 to be rigid relative to the body portion 202. The perimeter support portion 206 further surrounds the hollow central portion 208. This embodiment further includes 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 made of solid steel and is preferably cast together with the main body portion 202.

[0025] As described above, the intermediate sandwich layer 126 is supported by the periphery 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 behind the face center FC. The periphery support portion 206 preferably has a width between about 2 mm and 20 mm. More preferably, the periphery support portion has a first topline width W of about 2 mm to 5 mm adjacent to the topline portion 212. TL And, adjacent to the sole portion 216, there is a second sole width W of approximately 6mm to 20mm. S It has a second sole width W S The first top line width W TL It is at least 1.5 times. Furthermore, the internal face support 204 has hollow central portions 208a and 208b that do not support the intermediate sandwich layer 126, and this internal face support 204 abuts against the back surface of the intermediate sandwich layer 126 between 25% and 75%, so that 75% to 25% of the intermediate sandwich layer 126 is unrestrained. In this embodiment, the vertical support portion 222 has a vertical support length L V and vertical support width W V It has a vertical support length L. V This 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 The vertical support width is approximately between 15mm and 30mm. V The width is between approximately 8 mm and 15 mm. Most preferably, the vertical support width W V The vertical support length L V It is between approximately 30% and 70%. In this way, the COR of the striking 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 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, which 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 further comprises an internal face support 304, which includes a perimeter support portion 306 and a central portion 308. The perimeter support portion 306 is made of solid steel and is preferably cast together with the body portion 302 to be rigid relative to the body portion. The perimeter support portion 306 further surrounds the 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 made of solid steel and is preferably cast together with the main body portion 302.

[0027] As described above, the intermediate sandwich layer 126 is supported by the periphery 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 periphery support portion 306 preferably has a width between about 2 mm and 20 mm. More preferably, the periphery support portion has a first topline width W between about 2 mm and 5 mm adjacent to the topline portion 312. TL And, adjacent to the sole portion 316, the second sole width W is between approximately 6mm and 20mm. S It has a second sole width W S The first top line width W TLIt is at least 1.5 times. Furthermore, the internal face support 304 has hollow central portions 308a and 308b that do not support the intermediate sandwich layer 126, and this internal face support 304 is adjacent to the back of the intermediate sandwich layer 126 between 25% and 75%, so that 75% to 25% of the intermediate sandwich layer 126 is unrestrained. In this embodiment, the horizontal support portion 322 has a horizontal support length L H and horizontal support width W H It has a horizontal support length L. H This is measured from the heel portion of the periphery support portion 306 to the toe portion of the periphery support portion 306. Preferably, the horizontal support length L H The horizontal support width is approximately between 40mm and 80mm. H The width is approximately between 5 mm and 10 mm. Most preferably, the horizontal support width W H The horizontal support length L H This ranges from approximately 5% to 25%. This allows the COR of the impact face portion 110 at the center FC of the face to be controlled across the entire impact face portion 110, thereby achieving a solid feel.

[0028] Figures 7 and 8 of the attached 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 which is joined to the body portion 402, preferably by welding or integral casting, and which forms a cavity between them. The golf club head 400 further has an internal face support 404 which includes a perimeter support portion 406 and a central portion 408. The perimeter support portion 406 is preferably a thermoplastic insert positioned within the body portion 402 so as to be rigid with respect to the body portion 402. The perimeter 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-side portion 408a and a hollow heel-side portion 408b.

[0029] The striking face portion 410 shown in Figure 7 includes a front face portion 424 having a face center. The front face portion 424 may be formed as a face cup, thereby forming the leading edge LE, and also includes a toe portion 414, a topline portion 412, and a sole portion 416 of the main body portion, which are preferably joined by welding. The outer front face portion 424 is preferably made of steel and is located on the outer front portion of the striking face portion 410. The outer front face portion 424 has a substantially flat striking outer surface 432 including a plurality of grooves (not shown). More preferably, the outer front face portion 424 is made of high-strength steel having an ultimate tensile strength of more than 2000 MPa, more preferably more than 2300 MPa. Most preferably, the outer front face portion 424 is made of AerMet340 or the like. Furthermore, the external front face portion 424 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the external front face portion 424 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin external front face portion 424 and its high strength help to produce a high COR of the golf club head 400. Alternatively, the striking face portion 410 may be integrally cast from steel, similar to the body portion 402.

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

[0031] The internal face support 404 is fixed within the internal hollow portion 429 of the golf club head 400. The internal face support 404 is preferably formed from a thermoplastic 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 internal 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 described above, the intermediate sandwich layer 426 is a polymer material having a tensile strength in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa, when measured according to ASTM D412. 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 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 426 is composed of a silicone material, more preferably of a silicone rubber such as SH9151U sold by KCC Silicone Corporation. Furthermore, the intermediate sandwich layer 426 preferably has a substantially uniform thickness between about 1 mm to 10 mm, more preferably between about 3 mm and 7 mm. The intermediate sandwich layer 426 also preferably has a thickness of at least twice the thickness of the outer front face portion at the face center FC.

[0033] As described above, the peripheral support portion 406 preferably has a width between approximately 2 mm and 20 mm. More preferably, the peripheral support portion has a first top line width W of approximately 2 mm to 5 mm adjacent to the top line portion 412. TL And, adjacent to the sole portion 416, there is a second sole width W of approximately 6mm to 20mm. S It is equipped with the first width W TL It is at least 1.5 times. Furthermore, the internal face support 404 has a hollow central portion 408 that does not support the intermediate sandwich layer 426 and only contacts 25% to 75% of the back surface of the intermediate sandwich layer, while the intermediate sandwich layer 426 covers 90% to 100% of the back surface of the external front face portion 424. Thus, although the external front face portion 424 is substantially attenuated by the intermediate sandwich layer 426, 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 LV and vertical support width W V It is equipped with a vertical support length L. V This 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 The vertical support width is approximately between 15mm and 30mm. V The width is between approximately 8 mm and 15 mm. Most preferably, the vertical support width W V The vertical support length L V It is between approximately 30% and 70%. In this way, the COR of the striking 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 1 / 2 inch from the face center FC toward the heel.

[0034] Figure 9 of the attached drawings shows a golf club head body portion 502 that can be combined with the striking face portion 110 disclosed in Figure 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 has a striking face portion 110, which is preferably joined to the body portion 502 by welding or integral casting, forming a cavity between them. The golf club head further has an internal face support 504 including a perimeter support portion 506 and a central portion 508. The perimeter support portion 506 is preferably a thermoplastic insert positioned within the body portion 502, thereby having rigidity relative to the body portion 502. The perimeter 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-side portion 508a and a hollow heel-side portion 508b.

[0035] Similar to the previous example, the striking face portion 110 shown in Figure 2 includes a front face portion 124 having a face center FC. The front face portion 124 may be formed as a face cup, thereby forming a leading edge LE, and comprises a toe portion 514, a topline portion 512, and a sole portion 516 of the main body portion, which are joined, preferably by welding. The outer front face portion 124 is preferably made of steel and is located on the outer front portion of the striking face portion 110. The outer front face portion 124 has a substantially flat striking outer surface, which includes a plurality of grooves, although not shown. More preferably, the outer front face portion 124 is made of high-strength steel having an ultimate tensile strength of more than 2000 MPa, more preferably more than 2300 MPa. Most preferably, the outer front face portion 124 is made of AerMet340 or the like. Furthermore, the external front face portion 124 preferably has a uniform thickness of about 0.6 mm to about 2.4 mm. Most preferably, the external front face portion 124 has a uniform thickness of about 1.4 mm to about 1.8 mm. This thin external front face portion 124 and its high strength help to produce a high COR of 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 Figure 3, is sandwiched in the cavity between the back of the front face portion 124 and the internal face support 504. The intermediate sandwich layer 126 has a front opposing surface 127 that has substantially the same area as the rear surface of the front face portion 124. Preferably, the intermediate sandwich layer 126 is supported around its periphery by the internal face support 504. That is, the intermediate sandwich layer 126 is supported by the internal face support periphery support portion 506 near the topline portion 512, the toe portion 514, and the sole portion. However, the internal 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 internal face support 504 is fixed to the internal hollow portion of the golf club head. The internal face support 504 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 internal 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 polymer material having a tensile strength in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa, when measured according to ASTM D412. 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 becoming 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 composed of a silicone material, more preferably of 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 and 7 mm. Furthermore, the intermediate sandwich layer 126 preferably has a thickness at least twice that of the outer front face portion at the face center FC.

[0039] As described above, the peripheral support portion 506 preferably has a width between approximately 2 mm and 20 mm. More preferably, the peripheral support portion has a first top line width W of approximately 2 mm to 5 mm adjacent to the top line portion 512. TL And, adjacent to the sole portion 516, there is a second sole width W of approximately 6mm to 20mm. S It has a second sole width W S The first width W TLIt is at least 1.5 times. Furthermore, the internal face support 504 has a hollow central portion 508 that does not support the intermediate sandwich layer 126, and contacts only 25% to 75% of the back surface of the intermediate sandwich layer 126, yet covers 90% to 100% of the intermediate sandwich layer 126. Thus, although the external front face portion 124 is substantially damped and supported by the intermediate sandwich layer 126, 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 horizontal support width W H It is equipped with a horizontal support length L. H This 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 The horizontal support width is approximately between 40mm and 80mm. H The width is approximately between 5 mm and 10 mm. Most preferably, the horizontal support width W H The horizontal support length L H This ranges from approximately 5% to 25%. This allows the COR of the impact face portion 110 at the center FC of the face to be controlled across the entire impact face portion 110, resulting in a solid feel.

[0040] Figures 10 and 11 disclose alternative embodiments of the golf club head body disclosed in Figure 5, which can be used in place of the body portion 202 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 600 shown herein 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, which includes a perimeter support portion 606 and a central portion 608. The perimeter support portion 606 is made of solid steel and is preferably cast together with the body portion 602 to be rigid relative to the body portion 602. The perimeter support portion 606 further surrounds the hollow central portion 608. This embodiment further includes 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 made of solid steel and is preferably cast together with the main body portion 602.

[0041] As described above, the intermediate sandwich layer 126 is supported by the periphery 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 behind the face center FC. The periphery support portion 606 preferably has a width between about 2 mm and 20 mm. More preferably, the periphery support portion has a first topline width W of about 2 mm to 5 mm adjacent to the topline portion 612. TL And, adjacent to the sole portion 616, there is a second sole width W of approximately 6mm to 20mm. S It is equipped with a second sole width W S The first top line width W TLIt is at least 1.5 times. Furthermore, the internal face support 604 has hollow central portions 608a and 608b that do not support the intermediate sandwich layer 126, and the internal face support 604 abuts the back surface of the intermediate sandwich layer 126 between 25% and 75% of it, so that 75% to 25% of the intermediate sandwich layer 126 is unrestrained. 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 It is equipped with the following: Vertical support length L VA , L VB , and L VC This 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 The vertical support width is between approximately 15mm and 30mm. V The width is between approximately 8 mm and 15 mm. Most preferably, the vertical support width W V The vertical support length L VA , L VB , and L VC It is between approximately 30% and 70%. Thus, the COR of the striking 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 1 / 2 inch from the face center FC toward the heel. In this embodiment, the vertical support portion 622 is further divided into three parts: the central vertical support portion 622a, the top vertical support portion 622b, and the bottom vertical support portion 622c. Preferably, the central vertical support portion 622a is substantially closer to the striking face portion 110, so that the intermediate sandwich layer 126 at the face center has a second perimeter thickness t of the perimeter support portion surrounding the face center. P A first thickness t that is smaller than FCThe structure comprises the following: As shown in the figure, 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 toward the striking face portion 110 from the surrounding support portion 606. Thus, the first thickness t at the center of the face FC This is a second circumferential thickness t of 1 / 2 inch from the center of the face toward the toe portion 614 and heel portion 618. P It is between approximately 80% and 40%. 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 It is equipped with the following, and the bottom vertical support portion 622c has a bottom vertical support length L VC It has a central vertical support length L. In a preferred embodiment, the central vertical support length L VA The vertical support length L is at the top. VB and bottom vertical support length L VC It is at least 20% greater than both of these. In this embodiment, the COR of the striking face portion 110 can be kept more constant near the face center FC.

[0042] Figures 12 and 13 of the attached drawings show the golf club head 700 and the 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 cast integrally 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 so as to be rigid to the body portion 702. The internal face support 704 is preferably coupled to the body portion 702 by abutting against or snapping into a plurality of lip portions 732 inside the body portion 702, or by fasteners 730 positioned near the heel portion 718. The support bar portion 706 is spaced apart from the topline portion 712 to facilitate insertion into the body portion 702, thereby 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 between about 2 mm and 5 mm. SB Furthermore, it has 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 Figure 7, is sandwiched within the 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 having substantially the same area as the back surface of the striking face portion 710. Preferably, the internal face support 704 has a plurality of openings 708 and gaps 734 that do not support the intermediate sandwich layer 726. Thus, the internal face support 704 contacts the back surface of the intermediate sandwich layer for only 25% to 75% of its surface, while the intermediate sandwich layer 726 covers 90% to 100% of the back surface of the striking face portion 710.

[0044] As described above, the intermediate sandwich layer 726 is a polymer material having a tensile strength in the range of about 4 MPa to 20 MPa, more preferably 6 MPa to 12 MPa, when measured according to ASTM D412. 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, in order to prevent 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, more preferably a silicone rubber such as SH9151U sold by KCC Silicone Corporation. Furthermore, 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 the thickness of the striking face portion 710 at the face center FC.

[0045] Figures 14-16 of the attached drawings show a portion of the golf club head 800. According to an exemplary embodiment of the present invention, the rear body portion, i.e., the body portion 802, includes a toe portion 814, a sole portion 816, a heel portion 818, and a hosel 820, which can be cast integrally with the striking face portion 810. The golf club head further has an internal face support 804 including a topline portion 812, a central support portion 805, and a plurality of openings 808. As described 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 positioned within the body portion 802 so as to be rigid to the body portion 802. The internal face support 804 is preferably coupled to the body portion 802 by contacting or snapping into a plurality of lip portions 832 inside the body portion 802 and the ledge portions 834 of the toe portion 814 and heel portion 818. Fasteners may be incorporated as needed. Preferably, the central support portion 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 Figure 12, is preferably sandwiched in the cavity between the back surface of the striking face portion 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. Preferably, the internal face support 804 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 portion 810.

[0047] Except for the examples of operation, or unless otherwise specified, all numerical ranges, quantities, values, and percentages in the preceding portions of this specification, such as material quantities, moments of inertia, center of gravity, loft, draft angles, various performance ratios, and others, may be understood as if preceded by the term "approximately," even if the term "approximately" does not explicitly appear in the value, quantity, or range. Therefore, unless otherwise indicated, the numerical parameters described in the above specification and the appended claims are approximations that may vary depending on the desired properties to be obtained by this invention. At the very least, without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be interpreted by applying ordinary rounding techniques, at least in light of the reported number of significant figures.

[0048] Although the numerical ranges and parameters representing the broad scope of this invention are approximations, the numerical values ​​shown in specific examples are reported as accurately as possible. However, the numerical values ​​inherently contain certain errors due to the standard deviation found in each test measurement. Furthermore, it should be noted that where numerical ranges of various types are described herein, any combination of these values, including the listed values, may be used.

[0049] Of course, the above description relates to illustrative embodiments of this invention, and it should be understood that modifications can be made without departing from the spirit and scope of this invention as set forth in the following claims. The following lists the technical features described here. [Technical Feature 1] In iron-type golf clubs, The golf club has a golf club head, a grip, and a shaft between them. The above golf club head is The striking face portion located on the front part of the golf club head, comprising the center of the striking face portion, the rear surface of the striking face portion, and the thickness at the center of the striking face portion between 0.6 mm and 2.4 mm, A rear body portion which is connected to the above-mentioned striking face portion, forms a cavity between itself and the above-mentioned striking face portion, and forms the top line portion, sole portion, toe portion, heel portion, and hosel, An internal support layer positioned within the above cavity and coupled to the above rear body portion, comprising the above internal support layer and having a front surface, An intermediate sandwich layer is positioned between the above-mentioned striking face portion and the above-mentioned internal support layer, and has a sandwich face layer hardness of less than 75 Shore A, having a thickness of 1 mm to 10 mm at the center of the face, and comprising an intermediate sandwich layer front surface and an intermediate sandwich layer back surface, An iron-type golf club characterized in that the front surface of the internal support layer is in contact with the back surface of the intermediate sandwich layer by 25% and 75% of its surface. [Technical Feature 2] The golf club according to technical feature 1, wherein the front surface of the intermediate sandwich layer contacts the back surface of the striking face portion by a margin of 90% to 100%. [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 base thickness of 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 the heel section of the surrounding support portion to the toe section of the surrounding support portion. [Technical Feature 5] The golf club according to technical feature 3, wherein the internal support layer further has a vertical support section extending from the topline section of the surrounding support portion to the sole section of the surrounding support portion. [Technical Feature 6] The golf club described in technical feature 3, wherein the internal support layer is made of steel and is cast integrally with the rear body portion. [Technical Feature 7] The golf club according to technical feature 3, wherein the internal support layer is made of a thermoplastic material having an internal support layer tensile strength at least 10 times greater than the tensile strength of the intermediate sandwich layer. [Technical Feature 8] The golf club described in technical feature 1, wherein the striking face portion has a thickness of between 1.4 mm and 1.8 mm at the center of the face. [Technical Feature 9] The golf club according to technical feature 1, wherein the above-mentioned intermediate sandwich layer has a thickness of 4 mm to 7 mm at the center of the face. [Technical Feature 10] The above-mentioned peripheral support portion is adjacent to the above-mentioned topline portion, with a topline width W between 2mm and 5mm. TL , and adjacent to the above sole portion, sole width W between 6mm and 20mm S A golf club possessing the technical features described in technical feature 3. [Technical Feature 11] The above sole width W S The above top line width W TL A golf club described in technical feature 10, which is at least 1.5 times the size of the club. [Technical Feature 12] The above horizontal support section has a horizontal support width W between 5mm and 10mm. H A golf club possessing the technical features described in technical feature 4. [Technical Feature 13] The above vertical support section has a vertical support width W between 8mm and 15mm. V A golf club possessing the technical features described in technical feature 5. [Technical Feature 14] The golf club according to technical feature 13, wherein the above vertical support section is closer to the striking face portion, and the above intermediate sandwich layer has a face center thickness between 80% and 40% of the thickness of the intermediate sandwich layer closer to the toe portion. [Technical Feature 15] The golf club according to technical feature 13, wherein the above vertical support section comprises a central portion closer to the striking face portion, so that the intermediate sandwich layer has a thickness at the center of the face that is between 80% and 40% of the thickness of the intermediate sandwich layer closer to the heel portion. [Technical Feature 16] In iron-type golf clubs, The golf club has a golf club head, a grip, and a shaft between them. The above golf club head is The striking face portion located on the front part of the golf club head, the striking face portion having a center and a thickness at the center of the face between 0.8 mm and 2.4 mm, A rear body portion which is connected to the above-mentioned striking face portion, forms a cavity between itself and the above-mentioned striking face portion, and forms the top line portion, sole portion, toe portion, heel portion, and hosel, An internal support layer, the internal support layer being positioned within the cavity and coupled to the rear body portion such that it has a front opposing front surface, An intermediate sandwich layer is placed between the above-mentioned striking face portion and the above-mentioned internal support layer, having a thickness of 1 mm to 10 mm at the center of the face, comprising an intermediate sandwich layer back surface and a front surface, and made of a polymer material having a sandwich face layer tensile strength between 4 MPa and 20 MPa, wherein the intermediate sandwich layer is provided. The iron-type golf club is characterized in that the internal support layer has a thermoplastic material having a support layer tensile strength between 60 MPa and 300 MPa, and the internal support layer surrounds the cavity and has a peripheral support portion having a peripheral thickness between 2 mm and 20 mm and a peripheral support portion having a thickness between 0.5 mm and 5 mm. [Technical Feature 17] The golf club according to technical feature 16, wherein the striking face portion has a back surface, and the front surface of the intermediate sandwich layer contacts the back surface of the striking face portion by 90% to 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 the heel section of the surrounding support portion to the 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 perimeter 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 the topline section of the surrounding support portion to the sole section of the surrounding support portion. [Technical Feature 21] The golf club 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. [Explanation of symbols]

[0050] 100 Golf Club Heads 102 Main body part 104 Internal Face Support 106 Surrounding support part 108 Hollow central part 110 Hitting Face 112 Top line section 113 Top line section 114 Toe section 115 Toe section 116 Sole 117 Sole 118 Heel part 120 Hosel 124 External front face section 125 Folded section 126. Middle sandwich layer 127 Front facing surface 129 Internal hollow part 132 Impact outer surface 200 Golf Club Heads 202 Main body part 204 Internal Face Support 206 Surrounding support part 208 Hollow central part 212 Top line section 214 Toe section 216 Sole 218 Heel part 220 Hosel 222 Vertical support section 300 Golf Club Heads 302 Main body part 304 Internal Face Support 306 Surrounding support part 308 Hollow central part 312 Top line section 314 Toe section 316 Sole 318 Heel part 320 Hosel 322 Horizontal support section 400 Golf Club Heads 402 Main body part 404 Internal Face Support 406 Surrounding support section 408 Hollow central part 410 Hitting Face 412 Top line section 414 Toe section 416 Sole 418 Heel part 420 Hosel 422 Vertical support section 424 External front face section 425 Front facing surface 426 Middle sandwich layer 429 Internal hollow part 432 Impact outer surface 502 Main body part 504 Internal Face Support 506 Surrounding support part 508 Hollow central part 512 Top line section 514 Toe section 516 Sole 518 Heel part 520 Hosel 522 Horizontal support section 600 Golf Club Heads 602 Main body part 604 Internal Face Support 606 Surrounding support section 608 Hollow central part 612 Top line section 614 Toe section 616 Sole 618 Heel part 620 Hosel 622 Vertical support section 700 Golf Club Heads 702 Main body part 704 Internal Face Support 705 Central support section 706 Support bar section 708 Opening 710 Hitting Face 712 Top line section 714 Toe section 716 Sole 718 Heel part 720 Hosel 726 Middle sandwich layer 730 Fastener 732 Lip part 734 Gap 800 Golf Club Heads 802 Main body part 804 Internal Face Support 805 Central support section 808 Opening 810 Hitting Face 812 Top line section 814 Toe section 816 Sole 818 Heel part 820 Hosel 832 Lip part 834 Ledge section

Claims

1. In iron-type golf clubs, The golf club has a golf club head, a grip, and a shaft between them. The above golf club head is The striking face portion located on the front part of the golf club head, the striking face portion having a center and a thickness at the center of the face between 0.8 mm and 2.4 mm, A rear body portion which is connected to the above-mentioned striking face portion, forms a cavity between itself and the above-mentioned striking face portion, and forms the top line portion, sole portion, toe portion, heel portion, and hosel, An internal support layer, the internal support layer being positioned within the cavity and coupled to the rear body portion such that it has a front opposing front surface, An intermediate sandwich layer is placed between the above-mentioned striking face portion and the above-mentioned internal support layer, having a thickness of 1 mm to 10 mm at the center of the face, comprising an intermediate sandwich layer back surface and a front surface, and made of a polymer material having a sandwich face layer tensile strength between 4 MPa and 20 MPa, wherein the intermediate sandwich layer comprises The iron-type golf club is characterized in that the internal support layer has a thermoplastic material having a support layer tensile strength between 60 MPa and 300 MPa, and the internal support layer surrounds the hollow portion and has a peripheral support portion having a peripheral thickness between 2 mm and 20 mm and a peripheral support portion having a thickness between 0.5 mm and 5 mm.

2. The golf club according to claim 1, wherein the striking face portion has a back surface, and the front surface of the intermediate sandwich layer contacts the back surface of the striking face portion by a margin of 90% to 100%.

3. The golf club according to claim 1, wherein the internal support layer further comprises a horizontal support section extending from the heel section of the surrounding support portion to the toe section of the surrounding support portion.

4. The golf club according to claim 1, wherein the internal support layer further comprises a vertical support section extending from the topline section of the surrounding support portion to the sole section of the surrounding support portion.

5. The golf club according to claim 1, wherein the tensile strength of the support layer is at least 10 times greater than the tensile strength of the sandwich face layer.

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