Golf club shaft

• US 20080026868A1
• Filed: 06/13/2007
• Published: 01/31/2008
• Est. Priority Date: 07/27/2006
• Status: Active Grant

• Current Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Original Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Inventors: Takeuchi, Hiroyuki
• Granted Patent: US 7,500,922 B2
• Time in Patent Office: Days
• US Class Current: 473/319
• CPC Class Codes: A63B 2209/02 with reinforcing fibres, e.g. carbon, polyamide fibres
• CPC Class Codes: A63B 2209/023 Long, oriented fibres, e.g. wound filaments, woven fabrics, mats
• CPC Class Codes: A63B 53/10 Non-metallic shafts
• CPC Class Codes: A63B 60/002 Resonance frequency related characteristics
• CPC Class Codes: A63B 60/06 Handles
• CPC Class Codes: A63B 60/08 characterised by the material
• CPC Class Codes: A63B 60/10 with means for indicating correct holding positions A63B60/12 takes precedence
• CPC Class Codes: 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
• CPC Class Codes: A63B 60/54 with means for damping vibrations

Abstract

A golf club shaft (10), tubular and having a hollow portion, which includes a laminate of fiber reinforced prepregs (21 through 23, 24A, 25 through 29). The laminate has a first part (I) composed of a plurality of first prepregs (P1) and a second part (P2). A loss factor (tan δ) of the first part (I) is set to not less than 0.005 nor more than 0.02, when the loss factor is measured at a frequency of 10 Hz under a condition of 10° C. A loss factor (tan δ) of the second part (P2) is set to not less than 0.10 nor more than 0.50, when the loss factor is measured at a frequency of 10 Hz under the condition of 10° C.

Claims

1. A golf club shaft, tubular and having a hollow portion, comprising a laminate of fiber reinforced prepregs composed of a matrix resin and reinforcing fibers impregnated with said matrix resin,

wherein said laminate includes has a first part composed of a plurality of first prepregs and a second part,

a loss factor (tan δ

) of said first part is set to not less than 0.005 nor more than 0.02, when said loss factor is measured at a frequency of 10 Hz under a condition of 10°

C.; and

a loss factor (tan δ

) of said second part is set to not less than 0.10 nor more than 0.50, when said loss factor is measured at a frequency of 10 Hz under said condition of 10°

C.

2. The golf club shaft according to claim 1, wherein a weight of said second part is set to not less than 1% nor more than 15% of a weight of said first part composed of a plurality of said first prepregs layered on one another.

3. The golf club shaft according to claim 1, wherein supposing that an entire thickness of said fiber reinforced resin layer is 100%, at least one part of said second part is disposed in a thickness range within 20% of said entire thickness of said fiber reinforced resin layer at one and other sides in a thickness direction with respect to a central position of said entire thickness.

4. The golf club shaft according to claim 1, wherein a matrix resin composition of said second part contains epoxy resin and an activator having dipoles added to said epoxy resin,

a modulus of elasticity in tension of reinforcing fibers of said first prepreg and said second part is set to not less than 15 tonf/mm² nor more than 60 tonf/mm².

5. The golf club shaft according to claim 4, wherein said second part comprises a composition containing epoxy resin and one or more activators selected from among compounds having a benzotriazole group and compounds having a diphenyl acrylate group added to said epoxy resin.

6. The golf club shaft according to claim 1, wherein said second part is disposed in a region from a head-side tip of said golf club shaft to a position spaced at an interval of 30% of a whole length of said golf club shaft from said head-side tip of said golf club shaft.

7. The golf club shaft according to claim 1, wherein an orientation angle of reinforcing fibers of said second part to an axis of said golf club shaft is set to not less than 30°

nor more than 90°

.