IP Library Granted Patent US 9,566,485
Granted Patent B2
US 9,566,485 · App. 14/055,050 · Granted Feb 14, 2017

Golf club shaft

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Quick Facts
Patent No.
US 9,566,485
App. No.
14/055,050
Granted
Feb 14, 2017
Kind
B2
Abstract

A shaft 6 includes full length layers provided wholly in a longitudinal direction of the shaft, and a tip end partial layer provided on a tip part of the shaft. The full length layers include a bias layer and a straight layer. The tip end partial layer includes an inner glass fiber reinforced layer. When a full length of the shaft 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, a ratio (Lg/Ls) is equal to or greater than 0.52 and equal to or less than 0.65. A weight of the shaft is equal to or less than 65 g. Preferably, the inner glass fiber reinforced layer is positioned inside the bias layer.

Claims (16)

1. A golf club shaft comprising:

full length layers disposed wholly in a longitudinal direction of the shaft;

a tip end partial layer disposed on a tip part of the shaft; and

a hoop layer that includes a middle partial hoop layer;

wherein the full length layers include a bias layer and a straight layer;

the tip end partial layer includes an inner glass fiber reinforced layer;

when a full length of the shaft 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, a ratio (Lg/Ls) is 0.52 or greater and 0.65 or less and the full length Ls of the shaft is equal to or greater than 44 inches;

a weight of the shaft is equal to or less than 65 g;

wherein the shaft is equally divided into three in the longitudinal direction to section the shaft into a tip region, a middle region, and a butt region;

if a weight of the hoop layer in the tip region is defined as Rf 1 , a weight of the hoop layer in the middle region is defined as Rf 2 , and a weight of the hoop layer in the butt region is defined as Rf 3 , the weight Rf 2 is greater than the weight Rf 1 , and the weight Rf 2 is greater than the weight Rf 3 ;

if a length of the middle partial hoop layer in the longitudinal direction is defined as Lz, Lz/Ls is equal to or greater than 0.45; and

wherein the bias layer and the straight layer as the full length layers are formed of carbon fiber reinforcing prepregs.

2. The golf club shaft according to claim 1 , wherein the inner glass fiber reinforced layer is positioned inside the bias layer.

3. The golf club shaft according to claim 1 , wherein the inner glass fiber reinforced layer is an innermost layer.

4. The golf club shaft according to claim 1 , wherein, when a weight of the shaft in the tip region is defined as Ws 1 , a weight of the shaft in the middle region is defined as Ws 2 , and a weight of the shaft in the butt region is defined as Ws 3 , (Ws 1 +Ws 3 )/Ws 2 is equal to or greater than 2.1.

5. The golf club shaft according to claim 1 , wherein, when a weight of the shaft in the middle region is defined as Ws 2 and a weight of the shaft in the butt region is defined as Ws 3 , Ws 3 /Ws 2 is 1.1 or greater and 2 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 Oct 28, 2013
From: HASEGAWA, HIROSHI; MATSUNAGA, KIYOFUMI; SHIMAUCHI, TAKESHI
To: DUNLOP SPORTS CO. LTD.
Reel/Frame 031492/0325 →