Shaft for golf clubs
View Patent ↗A shaft 6 includes bias layers and straight layers. The bias layers include full length bias layers s1, s2, and butt partial bias layers s3, s4 arranged at a butt end side of the shaft. The straight layers include full length straight layers s7, s9, a tip partial straight layer arranged at a tip side of the shaft, and a butt partial straight layer arranged at a butt end side of the shaft. The tip partial straight layer includes a tip low-elastic layer s6. The butt partial straight layer includes a butt low-elastic layer s8. A low-elastic layer means a layer in which an elastic modulus of a reinforcing fiber is equal to or less than 20 ton/mm 2 . A shaft length Ls is equal to or less than 41 inches.
1. A golf club shaft comprising:
a bias layer; and
a straight layer,
wherein the bias layer includes a butt partial bias layer arranged at a butt end side of the shaft;
the straight layer includes a tip partial straight layer arranged at a tip side of the shaft and a butt partial straight layer arranged at the butt end side of the shaft;
if a layer in which an elastic modulus of a reinforcing fiber is equal to or less than 20 ton/mm 2 is defined as a low-elastic layer,
the tip partial straight layer includes a tip low-elastic layer, and the butt partial straight layer includes a butt low-elastic layer; and
a shaft length Ls is equal to or less than 41 inches,
wherein the tip low-elastic layer and the butt low-elastic layer are glass fiber reinforced layers; and
if a total weight of the glass fiber reinforced layers is defined as Wg, and a shaft weight is defined as Ws, Wg/Ws is less than 0.10.
2. The golf club shaft according to claim 1 , wherein an axial direction distance Lg between a tip of the shaft and a center of gravity of the shaft is 400 mm or greater and 750 mm or less; and
a shaft weight Ws is equal to or less than 65 g.
3. A golf club comprising:
a head;
a shaft; and
a grip,
wherein the shaft includes a bias layer and a straight layer;
the bias layer includes a butt partial bias layer arranged at a butt end side of the shaft;
the straight layer includes a tip partial straight layer arranged at a tip side of the shaft and a butt partial straight layer arranged at the butt end side of the shaft;
if a layer in which an elastic modulus of a reinforcing fiber is equal to or less than 20 ton/mm 2 is defined as a low-elastic layer,
the tip partial straight layer includes a tip low-elastic layer, and the butt partial straight layer includes a butt low-elastic layer; and
a shaft length Ls is equal to or less than 41 inches,
wherein the tip low-elastic layer and the butt low-elastic layer are glass fiber reinforced layers; and
if a total weight of the glass fiber reinforced layers is defined as Wg, and a shaft weight is defined as Ws, Wg/Ws is less than 0.10.
4. The golf club shaft according to claim 1 , wherein if an axial direction distance between a tip of the shaft and a center of gravity of the shaft is defined as Lg, and a length of the shaft is defined as Ls,
Lg/Ls is 0.37 or greater and 0.81 or less.
5. A golf club shaft comprising:
a bias layer; and
a straight layer,
wherein the bias layer includes a butt partial bias layer arranged at a butt end side of the shaft;
the straight layer includes a tip partial straight layer arranged at a tip side of the shaft and a butt partial straight layer arranged at the butt end side of the shaft;
if a layer in which an elastic modulus of a reinforcing fiber is equal to or less than 20 ton/mm 2 is defined as a low-elastic layer,
the tip partial straight layer includes a tip low-elastic layer, and the butt partial straight layer includes a butt low-elastic layer; and
a shaft length Ls is equal to or less than 41 inches,
wherein the tip low-elastic layer and the butt low-elastic layer are glass fiber reinforced layers; and
if a portion between a position separated by 90 mm from a tip of the shaft and the tip of the shaft is defined as a specific tip end part;
a portion between a position separated by 50 mm from a butt end of the shaft and the butt end of the shaft is defined as a specific butt end part;
a weight of the specific tip end part is defined as Wt;
a weight of the specific butt end part is defined as Wb;
a weight of the tip low-elastic layer in the specific tip end part is defined as Wt1; and
a weight of the butt low-elastic layer in the specific butt end part is defined as Wb1,
Wb1/Wb is greater than Wt1/Wt.
6. A golf club shaft comprising:
a bias layer; and
a straight layer,
wherein the bias layer includes a butt partial bias layer arranged at a butt end side of the shaft;
the straight layer includes a tip partial straight layer arranged at a tip side of the shaft and a butt partial straight layer arranged at the butt end side of the shaft;
if a layer in which an elastic modulus of a reinforcing fiber is equal to or less than 20 ton/mm 2 is defined as a low-elastic layer,
the tip partial straight layer includes a tip low-elastic layer, and the butt partial straight layer includes a butt low-elastic layer; and
a shaft length Ls is equal to or less than 41 inches,
wherein the tip low-elastic layer and the butt low-elastic layer are glass fiber reinforced layers; and
if a portion between a position separated by 90 mm from a tip of the shaft and the tip of the shaft is defined as a specific tip end part;
a portion between a position separated by 50 mm from a butt end of the shaft and the butt end of the shaft is defined as a specific butt end part;
a weight of the specific tip end part is defined as Wt;
a weight of the specific butt end part is defined as Wb;
a weight of the tip low-elastic layer in the specific tip end part is defined as Wt1; and
a weight of the butt low-elastic layer in the specific butt end part is defined as Wb1,
Wt1/Wt is 0.05 or greater and 0.20 or less, and
Wb1/Wb is 0.07 or greater and 0.25 or less.