# US 12,179,074 B2 · Golf club and weight piece for golf club > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,179,074 B2 - Document ID: US12179074B2 - Status: Granted - Kind: B2 - Application number: 17/567,233 - Filed: 2022-01-03 - Published: 2022-07-21 - Granted: 2024-12-31 - Earliest claimed: 2021-01-18 - Assignees: Sumitomo Rubber Industries, Ltd. - Applicants: Sumitomo Rubber Industries, Ltd. - Inventors: Kota Maeda; Hiroshi Hasegawa; Akihiko Kobayashi - Web page: https://patentgrep.com/patent/US12179074B2 ## CPC - A63B 53/08: with special arrangements for obtaining a variable impact - A63B 53/0466: {wood-type} - A63B 53/047: {iron-type} - A63B 53/0487: {for putters (A63B53/065 takes precedence)} - A63B 53/14: Handles - A63B 60/02: Ballast means for adjusting the centre of mass (A63B60/24, A63B60/54 take precedence) - A63B 60/08: characterised by the material - A63B 60/14: Coverings specially adapted for handles, e.g. sleeves or ribbons - A63B 60/16: Caps; Ferrules - A63B 60/24: Weighted handles - A63B 60/42: Devices for measuring, verifying, correcting or customising the inherent characteristics of golf clubs, bats, rackets or the like, e.g. measuring the maximum torque a batting shaft can withstand - A63B 60/50: with through-holes (A63B60/18 takes precedence; for stringing purposes A63B49/00) - A63B 60/54: with means for damping vibrations - A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H) ## Abstract A golf club includes a club shaft having a first end, a second end, and an inner peripheral surface defining an inner space of the club shaft, and a weight piece installed on a first end side of the club shaft. The weight piece includes an insertion portion located in the inner space, and an engagement portion located outside the club shaft to engage the first end. The insertion portion includes a first portion and a second portion. The first portion has an outer diameter smaller than the first inner diameter. The second portion includes a large diameter portion having an outer diameter larger than the first inner diameter in a state before being placed in the club shaft, and at least one rigidity-lowered portion that elastically deforms the second portion so that the outer diameter of the large diameter portion becomes smaller when receiving an external force. ## Claims ### Claim 1 A golf club comprising: a tubular club shaft having a first end with a first inner diameter, a second end, and an inner peripheral surface defining an inner space of the club shaft; a weight piece installed on a first end side of the club shaft; and a golf club head mounted on a second end side of the club shaft, wherein the weight piece comprises: a metal weight body, and an elastic body which is made of plastic, elastomer, or rubber, and in which the metal weight body is embedded, the elastic body defines: an insertion portion located in the inner space of the club shaft, and an engagement portion located outside the inner space of the club shaft to engage the first end of the club shaft so as not to enter into the inner space, wherein the engagement portion has an outer diameter being larger than the first inner diameter at the first end, and not larger than an outer diameter of the club shaft at the first end, the insertion portion comprises: a first portion on a first end side, and a second portion on a second end side, the first portion has an outer diameter smaller than the first inner diameter, and has the metal weight body embedded therein, the second portion comprises: a plurality of circumferentially-arranged large diameter portions, at which the outer diameter of the insertion portion is larger than the first inner diameter in a state before being placed in the club shaft, and a plurality of rigidity-lowered portions, which are formed alternately with the large diameter portions in a circumferential direction of the shaft so as to elastically deform the second portion so that the outer diameter at the large diameter portions becomes smaller when receiving an external force, and each of the rigidity-lowered portions is a thin-walled portion extending in an axial direction of the shaft, and the second portion is placed in the inner space in an elastically deformed state so that the large diameter portion is at least partially in contact with the inner peripheral surface of the club shaft due to its elastic restoring force. ### Claim 2 (depends on 1) The golf club according to claim 1, wherein the weight piece has a hollow portion penetrating through the weight piece in the axial direction. ### Claim 3 (depends on 1) The golf club according to claim 1, wherein the rigidity-lowered portions are formed at equal intervals in the circumferential direction. ### Claim 4 (depends on 1) The golf club according to claim 1, wherein the second portion comprises an enlarged diameter portion whose outer diameter, in a state before being placed in the club shaft, increases toward the second end. ### Claim 5 (depends on 4) The golf club according to claim 4, wherein on the second end side of the enlarged diameter portion, the second portion comprises a small diameter portion whose outer diameter at its end on the second end side, in the state before being placed on the club shaft, is smaller than the first inner diameter. ### Claim 6 (depends on 1) The golf club according to claim 1, wherein the first portion has an outer surface being provided with at least one protrusion protruding in a shaft radial direction to contact with the inner peripheral surface of the club shaft. ### Claim 7 (depends on 6) The golf club according to claim 6, wherein the at least one protrusion has a protrusion height increasing toward the engagement portion. ### Claim 8 A weight piece for golf club having a tubular club shaft having a first end with a first inner diameter, a second end, and an inner surface therein, the weight piece adapted to be installed on a first end side of the club shaft, the weight piece comprising: a metal weight body, and an elastic body which is made of plastic, elastomer, or rubber, and in which the metal weight body is embedded, the elastic body defines: an insertion portion to be located in the inner space of the club shaft, and an engagement portion to be located outside the inner space of the club shaft to engage the first end of the club shaft so as not to enter into the inner space, wherein the engagement portion has an outer diameter being larger than the first inner diameter at the first end, and not larger than an outer diameter of the club shaft at the first end, wherein the insertion portion comprises: a first portion on a first end side, and a second portion on a second end side, and the first portion has an outer diameter smaller than the first inner diameter, and has the metal weight body embedded therein, the second portion comprises: a plurality of circumferentially-arranged large diameter portions at which the outer diameter of the insertion portion is larger than the first inner diameter in a state before being placed in the club shaft, and a plurality of rigidity-lowered portions which are formed alternately with the large diameter portions in a circumferential direction of the shaft so as to elastically deform the second portion so that the outer diameter at the large diameter portions becomes smaller when receiving an external force, and each of the rigidity-lowered portions is a thin-walled portion extending in an axial direction of the shaft. ### Claim 9 (depends on 8) The weight piece for golf club according to claim 8, wherein the rigidity-lowered portions are formed at equal intervals in the circumferential direction. ### Claim 10 (depends on 8) The weight piece for golf club according to claim 8, wherein the second portion comprises an enlarged diameter portion whose outer diameter increases toward the second end. ### Claim 11 (depends on 8) The weight piece for golf club according to claim 8, wherein on the second end side of the enlarged diameter portion, the second portion comprises a small diameter portion whose outer diameter at an end on a second end side is smaller than the first inner diameter of the club shaft.