IP Library Granted Patent US 8,920,266
Granted Patent B2
US 8,920,266 · App. 13/724,940 · Granted Dec 30, 2014

Golf club shaft

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Quick Facts
Patent No.
US 8,920,266
App. No.
13/724,940
Granted
Dec 30, 2014
Kind
B2
Abstract

A shaft full length is defined as Ls and a distance between a tip end of the shaft and a center of gravity G of the shaft is defined as Lg. In a shaft 6 , Lg/Ls is 0.54 or greater and 0.65 or less. A shaft weight Ws is 50 g or greater and 85 g or less. The shaft 6 has at least three bias layer pairs. One bias layer pair of the three bias layer pairs is a pitch-containing bias layer pair having a pitch based carbon fiber. Two bias layer pairs of the three bias layer pairs are PAN-containing bias layer pairs having a PAN based carbon fiber. Preferably, the PAN-containing bias layer pairs are located outside and inside the pitch-containing bias layer pair.

Claims (21)

1. A golf club shaft, wherein when a shaft full length is defined as Ls and a distance between a tip end of the shaft and a center of gravity G of the shaft is defined as Lg, Lg/Ls is 0.54 or greater and 0.65 or less;

a shaft weight Ws is 50 g or greater and 85 g or less;

the golf club shaft has at least three bias layer pairs;

one bias layer pair of the three bias layer pairs is a pitch-containing bias layer pair having a pitch based carbon fiber; and

two bias layer pairs of the three bias layer pairs are PAN-containing bias layer pairs having a PAN based carbon fiber.

2. The golf club shaft according to claim 1 , wherein the PAN-containing bias layer pairs are located outside and inside the pitch-containing bias layer pair.

3. The golf club shaft according to claim 2 , wherein the three bias layer pairs are brought into contact with each other.

4. The golf club shaft according to claim 1 , wherein the one bias layer pair of the three bias layer pairs is a butt partial layer.

5. The golf club shaft according to claim 4 , wherein the butt partial layer is the PAN-containing bias layer pair.

6. The golf club shaft according to claim 5 , wherein the three bias layer pairs are brought into contact with each other.

7. The golf club shaft according to claim 4 , wherein the two bias layer pairs of the three bias layer pairs are full length layers.

8. The golf club shaft according to claim 7 , wherein the three bias layer pairs are brought into contact with each other.

9. The golf club shaft according to claim 7 , wherein the number of the bias layer pairs is 3.

10. The golf club shaft according to claim 7 , wherein the golf club shaft has one or more full length PAN-containing bias layer pairs and one or more full length pitch-containing bias layer pairs.

11. The golf club shaft according to claim 4 , wherein the three bias layer pairs are brought into contact with each other.

12. The golf club shaft according to claim 4 , wherein a distance L 2 between a tip side end position of the butt partial layer and a butt end of the shaft is 300 mm or greater and 550 mm or less.

13. The golf club shaft according to claim 1 , wherein the three bias layer pairs are brought into contact with each other.

14. The golf club shaft according to claim 1 , wherein when a GI value in a point separated by 890 mm from the tip end of the shaft is defined as GIb, GIb is 24 N·m 2 or greater and 59 N·m 2 or less.

15. The golf club shaft according to claim 1 , wherein when a GI value in a point separated by 90 mm from the tip end of the shaft is defined as GIt, GIt is 5.4 N·m 2 or greater and 8.8 N·m 2 or less.

16. The golf club shaft according to claim 1 , wherein when a GI value in a point separated by 890 mm from the tip end of the shaft is defined as GIb, and a GI value in a point separated by 90 mm from the tip end of the shaft is defined as GIt,

GIb/GIt is 5 or greater and 9 or less.

Assignments (2)
MERGER Recorded Apr 17, 2018
From: DUNLOP SPORTS CO. LTD.
To: SUMITOMO RUBBER INDUSTRIES, LTD.
Reel/Frame 045959/0204 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 27, 2012
From: TAKEUCHI, HIROYUKI
To: DUNLOP SPORTS CO. LTD.
Reel/Frame 029535/0907 →