Patent ID: 6354957
Filing Date: 2002-03-12
Classification: A63B

Abstract:
A golf club shaft comprising: a main body layer in which a first fiber-reinforced prepeg sheet, impregnated with synthetic resin, is rolled; and an adjustment layer in which a second fiber-reinforced prepeg sheet, impregnated with synthetic resin, is rolled, the adjustment layer being arranged inside the main body layer, wherein the specific gravity of the second fiber-reinforce prepeg sheet is higher than that of the first fiber-reinforced prepeg sheet, the elasticity of the second fiber-reinforced prepeg sheet is lower than that of the first fiber-reinforced prepeg sheet, and the main body layer includes an axial direction fiber layer on which a fiber-reinforced prepeg sheet, the axial direction fiber of which is impregnated with synthetic resin, is rolled and the specific gravity of the second fiber-reinforced prepeg sheet is higher than that of the fiber-reinforced prepeg composing the axial direction fiber layer, the elasticity of the second fiber-reinforced prepeg sheet is lower than that of the fiber reinforced prepeg composing the axial direction fiber layer, and the thickness of the adjustment layer is not lower than 50% of the thickness of the axial direction fiber layer of the main body layer, the amount of resin impregnation of the adjustment layer is larger than the amount of resin impregnation of the main body layer, and the adjustment layer adjusts a weight balance of the golf shaft into a heavier side while adjusting a bending rigidity into a smaller side to accumulate power therein.