Golf club shaft

Abstract

The aerodynamic performance of a golf club shaft is improved by texturing the outer surface of the hozzle end portion of the shaft shank to provide an arithmetic mean of profile roughness which is greater than about 0.50 microns. This profile roughness is significantly greater than the arithmetic mean of profile roughness of a conventional smooth surface of a golf club shaft, which is typically between about 0.47 microns and about 0.50 microns. A roughness average on the hozzle end portion of the shank of a golf club shaft of between about 4.3 microns and about 5.0 microns is preferable. The hozzle end portion having such an enhanced roughness average should extend at least about five centimeters and no greater than about fifty centimeters from the tip of the golf club shaft that is inserted into the club head hozzle. A golf club shaft having these features will create less wake turbulence and less wake vacuum in moving through the air during a golf swing than a conventional golf club shaft. This enhances the speed and control of movement of the golf club head during a golf swing.

I claim:  
     
         1 . In a golf club shaft which has a hozzle end terminating in a tip, an opposite butt end, and a shank that tapers from a smallest diameter at said hozzle end to a largest diameter at said but end, the improvement wherein the outer surface of said hozzle end of said shank has an arithmetic mean of profile roughness of greater than about 0.50 microns.  
     
     
         2 . A golf club shaft according to  claim 1  further characterized in that said hozzle end of said shank is no less than about five centimeters and no greater than about fifty centimeters in length and has an arithmetic mean of profile roughness of between about 4.3 microns and about 5.0 microns.  
     
     
         3 . A golf club shaft according to  claim 2  wherein said shank has a lower intermediate portion located longitudinally adjacent said hozzle end and an upper intermediate portion longitudinally adjacent said butt end and said intermediate portions are located longitudinally adjacent to each other, and said lower intermediate portion has an arithmetic mean of roughness profile about one-tenth that of said adjacent hozzle end, and said upper intermediate portion has an arithmetic mean of roughness profile greater than that of said lower intermediate portion and less them that of said hozzle end.  
     
     
         4 . In a golf club shaft having a hozzle end and a tip adjacent thereto for insertion into a golf club hozzle, the improvement wherein said hozzle end has an outer surface that is covered with a textured surface coating having an arithmetic mean of profile roughness of greater than about 0.5 microns.  
     
     
         5 . A golf club shaft according to  claim 4  wherein said arithmetic mean of profile roughness at said hozzle end is between about 4.3 microns and about 5.0 microns over a length of between about five centimeters and about fifty centimeters.  
     
     
         6 . A golf club shaft according to  claim 4  further comprising a lower intermediate portion adjacent said hozzle end between about ten centimeters and about fifty centimeters in length and having an outer surface with an arithmetic mean of roughness profile of between about 0.43 microns and about 0.50 microns.  
     
     
         7 . A golf club shaft according to  claim 6  further comprising an upper intermediate portion adjacent said lower intermediate portion between about ten centimeters and about fifty centimeters in length and having an outer surface with an arithmetic mean of roughness profile of between about 0.80 microns and about 0.90 microns.  
     
     
         8 . In a golf club shaft which has a hozzle end terminating in a tip, an opposite butt end, and a shank that tapers from a smallest diameter at said hozzle end to a largest diameter at said butt end, the improvement wherein at least a portion of the outer surface of said shank has a granulated surface texture thereon defining peaks with valleys therebetween, and said serviced texture has an arithmetic mean of profile roughness as measured between said peaks and valleys of at least about 0.50 microns.  
     
     
         9 . A golf club shaft according to  claim 8  wherein said profile roughness at said hozzle end adjacent said tip is at least about four microns and said profile roughness elsewhere on said surface of said shank is less than one micron.  
     
     
         10 . A golf club shaft according to  claim 9  wherein said hozzle end of said outer surface of said shank has a roughness profile of between about 4.3 microns and about 5.0 microns.  
     
     
         11 . A golf club shaft according to  claim 9  wherein said hozzle end of said shaft has a granulated surface with a roughness profile of between about 4.3 microns and about 5.0 microns over a length extending a distance of at least five centimeters from said tip.  
     
     
         12 . A golf club shaft according to  claim 11  wherein said hozzle end of said shaft has a granulated surface as aforesaid up to a maximum distance of about fifty centimeters from said tip.  
     
     
         13 . A golf club shaft according to  claim 8  wherein said golf club shaft shank has a lower intermediate portion and an upper intermediate portion located longitudinally adjacent said lower intermediate portion and said lower intermediate portion is located longitudinally between said hozzle end of said shank and said upper intermediate portion thereof, and said upper intermediate portion is located longitudinally between said lower intermediate portion and said butt end of said shank, and said surface of said shank at said lower intermediate portion is granulated with a service texture having an arithmetic mean of profile roughness about one-tenth that of said hozzle end.  
     
     
         14 . A golf club shaft according to  claim 13  wherein said surface of said shank at said upper intermediate portion is granulated with a surface texture having an arithmetic mean of profile roughness greater than that of said lower intermediate portion and less than that of said hozzle end.  
     
     
         15 . A golf club shaft according to  claim 14  wherein said surface of said shank is granulated with an arithmetic mean of profile roughness of between about 4.3 microns and about 5.0 microns at said hozzle end, between about 0.43 microns and about 0.50 microns at said lower intermediate portion, and between about 0.80 microns and about 0.90 microns at said upper intermediate portion.  
     
     
         16 . A golf club shaft according to  claim 13  wherein said arithmetic means of profile roughness are between about 4.3 microns and about 5.0 microns at said hozzle end; between about 0.43 microns and about 0.50 microns at said lower intermediate portion; and between about 0.80 microns and about 0.90 microns at said upper intermediate portion.  
     
     
         17 . A golf club shaft according to  claim 16  wherein said hozzle end of said shank is between about five centimeters and about fifty centimeters in length, said lower intermediate portion is between about ten centimeters and about fifty centimeters in length, said upper intermediate portion is between about ten centimeters and about fifty centimeters in length, and said butt end of portion is between about fifteen centimeters and about forty centimeters in length.