Golf club shaft and golf club using the same
A golf club shaft in which the isotropy of the prepregs configuring a torsion rigidity holding layer is high and in which sufficient torsional rigidity can be secured with fewer plies of fewer prepregs. The golf club shaft includes a torsional rigidity holding layer made of a thermosetting resin which contains reinforced fibers extending obliquely to a longitudinal direction of the shaft. The torsional rigidity holding layer includes a multilayer set prepreg, in which at least two layers of prepregs made of reinforced fibers are impregnated with a thermosetting resin. A plurality of prepregs in the multilayer set prepreg include reinforced fibers extending in mutually different directions. The multilayer set prepreg is continuously wound by at least two turns with the plurality of prepregs layered on each other. A golf club uses the shaft.
1. A golf club shaft comprising a torsional rigidity holding layer made of a thermosetting resin which contains reinforced fibers extending obliquely to a longitudinal direction of said shaft,
wherein said torsional rigidity holding layer comprises a multilayer set prepreg, in which at least two layers of prepregs made of reinforced fibers are impregnated with a thermosetting resin,
wherein a plurality of prepregs in said multilayer set prepreg include reinforced fibers extending in mutually different directions,
wherein said multilayer set prepreg is continuously wound by at least two turns with said plurality of prepregs layered on each other, and
wherein said multilayer set prepreg comprises a pair of multilayer set prepregs whose winding directions are mutually opposite.
2. The golf club shaft according to claim 1 , wherein said multilayer set prepreg comprises a fabric prepreg which is made by impregnating fiber-reinforced fabric with a thermosetting resin, and a UD prepreg which is made by impregnating reinforced fibers arranged to extend in a single direction with a thermosetting resin.
3. The golf club shaft according to claim 2 , wherein said fiber-reinforced fabric comprises at least one of a plain weave fabric, a triaxial woven fabric and a tetra-axial woven fabric.
4. The golf club shaft according to claim 2 , wherein said UD prepreg comprises a pair of oblique UD prepregs whose fiber directions are symmetrical with respect to said longitudinal direction of the shaft.
5. The golf club shaft according to claim 1 , further comprising a compressive rigidity holding layer which is configured from a UD prepreg whose fiber direction is orthogonal to said longitudinal direction of said shaft.
6. The golf club shaft according to claim 1 , further comprising a bending rigidity holding layer which is configured from a UD prepreg whose fiber direction is parallel to said longitudinal direction of said shaft.
7. The golf club shaft according to claim 1 , further comprising a decorative layer which is included in an outermost layer of said shaft and configured from a UD prepreg whose fiber direction is parallel to said longitudinal direction of said shaft.
8. A golf club comprising said golf club shaft according to claim 1 , to which a golf club head and a grip are fixed.