Golf club

Abstract

A golf club comprises a club shaft and a club head attached to the end of the club shaft, the club head volume is not less than 280 cc, the club head comprises a face portion which has, at least partially, a Young's modulus E of from 30 to 110 GPa, and the club shaft has a kick point index of not less than 50, wherein kick point index={inverse flexure/(inverse flexure+normal flexure)}×100.

1 . A golf club comprising 
 a club shaft and    a club head attached to the end of the club shaft,    the club head having a club head volume of not less than 280 cc and comprising a face portion which has, at least partially, a Young's modulus E of from 30 to 110 GPa,    the club shaft having a kick point index of not less than 50, wherein    kick point index={inverse flexure/(inverse flexure+normal flexure)}×100 wherein,    the normal flexure is the flexure of the club shaft measured as the displacement of a loading point in the vertical direction when the club shaft is horizontally supported at two points S 1 N abd S 2 N which are a first point S 1 N at a distance of 953 mm for supporting the under side and a second point S 2 N at a distance of 1093 mm for supporting the upper side, each distance measured from the end of the club shaft towards the opposite end of the club shaft, and the club shaft is loaded downward with 2.7 kgf at the loading point spaced apart from the end of the club shaft towards the opposite end by 129 mm,    the inverse flexure is the flexure of the club shaft measured as the displacement of a loading point in the vertical direction when the club shaft is horizontally supported at two points S 1 R and S 2 R which are a first point S 1 R at a distance of 152 mm for supporting the under side and a second point S 2 R at a distance of 12 mm for supporting the upper side, each distance measured from the end the club shaft towards the opposite end of the club shaft, and the club shaft is loaded downward with 1.3 kgf at the loading point spaced apart from the end of the club shaft towards the opposite end by 928 mm.    
     
     
         2 . A golf club according to  claim 1 , wherein 
 the kick point index is in a range of from 52 to 56.    
     
     
         3 . A golf club according to  claim 1 , wherein 
 a gravity point distance of the club head is 26 to 40 mm.    
     
     
         4 . A method of making a golf club, the golf club comprising a club shaft and a club head having a head volume of not less than 280 cc and comprising a face portion which has, at least partially, a Young's modulus E of from 30 to 110 GPa, said method comprising 
 selecting a kick point index for the club shaft from a range of not less than 50,    making the club shaft having the selected kick point index, and    attaching the club head to the end of the club shaft, wherein    kick point index={inverse flexure/(inverse flexure+normal flexure)}×100, wherein,    the normal flexure is the flexure of the club shaft measured as the displacement of a loading point in the vertical direction when the club shaft is horizontally supported at two points S 1 N and S 2 N which are a first point S 1 N at a distance of 953 mm for supporting the under side and a second point S 2 N at a distance of 1093 mm for supporting the upper side, each distance measured from the end of the club shaft towards the opposite end of the club shaft, and the club shaft is loaded downward with 2.7 kgf at the loading point spaced apart from the end of the club shaft towards the opposite end by 129 mm, and    the inverse flexure is the flexure of the club shaft measured as the displacement of a loading point in the vertical direction when the club shaft is horizontally supported at two points S 1 R and S 2 R which are a first point S 1 R at a distance of 152 mm for supporting the under side and a second point S 2 R at a distance of 12 mm for supporting the upper side, each distance measured from the end the club shaft towards the opposite end of the club shaft, and the club shaft is loaded downward with 1.3 kgf at the loading point spaced apart from the end of the club shaft towards the opposite end by 928 mm,