Hybrid golf club shaft

Abstract

A golf shaft for attachment to a hossel of a club head, said shaft comprising: (a) a first section comprising a first material and having a hossel end and a first joint end, said first section having a linear weight no greater than 2.4 g/in; (b) a second section comprising a second material and having a butt end and a second joint end, said second joint end being connected to said first joint end; (c) wherein said second material is less dense than said first material; and (d) wherein said first material has a shear modulus greater than that of said second material.

What is claimed is:  
     
         1 . A golf shaft for attachment to a hossel of a club head, said shaft comprising: 
 a first section comprising a first material and having a hossel end and a first joint end, said first section having a linear weight no greater than 2.4 g/in;    a second section comprising a second material and having a butt end and a second joint end, said second joint end being connected to said first joint end;    wherein said second material is less dense than said first material; and    wherein said first material has a shear modulus greater than that of said second material.    
     
     
         2 . The shaft of  claim 1 , further comprising: 
 a connector for connecting said hossel end to a hossel of a club head.    
     
     
         3 . The shaft of  claim 2 , wherein said connector is a stub adapted to be insertable in said hossel and said first section such that said first section and said hossel are butt joined.  
     
     
         4 . The shaft of  claim 3 , wherein said stub comprises a composite material.  
     
     
         5 . The shaft of  claim 4 , wherein said stub comprises graphite.  
     
     
         6 . The shaft of  claim 1 , wherein said linear weight of said first section is no greater than about 2 g/in.  
     
     
         7 . The shaft of  claim 6 , wherein said linear weight of said first section is no greater than about 1.8 g/in.  
     
     
         8 . The shaft of  claim 7 , wherein said weight per inch of said first section is no greater than about 1.7 g/in.  
     
     
         9 . The shaft of  claim 1 , wherein said section has an outside diameter greater than about 0.335″.  
     
     
         10 . The shaft of  claim 9 , wherein said outside diameter of said first section is no less than about 0.420″.  
     
     
         11 . The shaft of  claim 1 , wherein said first and second sections have a torsional stiffness no less than that of a 0.355″ O.D., 0.020″ thick, steel tube.  
     
     
         12 . The shaft of  claim 1 , wherein said first section is about 10 to about 40% of said total shaft length, and said second section is about 60 to about 90% of said total shaft length.  
     
     
         13 . The shaft of  claim 1 , wherein second section comprises a composite material;  
     
     
         14 . The shaft of  claim 13 , wherein said second section comprises graphite.  
     
     
         15 . The shaft of  claim 1 , wherein said first section comprises steel.  
     
     
         16 . The shaft of  claim 1 , further comprising internal stiffeners in the steel section to provide vibration damping.  
     
     
         17 . A golf club comprising: 
 a head having a hossel;    a first section comprising a first material and having a hossel end and a first joint end, said first section having a linear weight no greater than 2.4 g/in;    a connector for connecting said first section to said hossel;    a second section comprising a second material and having a butt end and a second joint end, said second joint end being connected to said first joint end;    wherein said second material is less dense than said first material; and    wherein said first material has a shear modulus greater than that of said second material.    
     
     
         18 . A method for modifying a conventional graphite shaft, said method comprising: 
 providing a first section of shaft having a linear weight no greater than about 2.4 g/in, and comprising a first material having a shear modulus greater than that of graphite;    providing a graphite shaft having a butt end and a hossel end;    removing a certain length of said graphite shaft from its hossel end; and    interengaging said first section with the end of said graphite shaft from which said certain length of shaft was removed.    
     
     
         19 . A customized section adapted for connection to a hossel of a club head and a section of a graphite shaft, said customized section having a linear weight no greater than about 2.4 g/in, and comprising a first material having a shear modulus greater than that of graphite.