Adjustable stiffness shaft structure

Abstract

A shaft structure with an adjustable stiffness is provided for golf clubs, fishing rods and like apparatuses. The shaft structure employs an inner and outer shaft structure. The golfer, in practice, configures the stiffness of a golf shaft, by adjusting the pressure of an inner shaft structure. The combination of outer and inner shaft structure stiffness results in an advantageous stiffness profile. The golfer can, at any time and very easily, change the stiffness profile of the golf shaft.

1 . An adjustable shaft structure comprising an inner shaft structure and outer st aft structure wherein the outside diameter of said inner shaft structure is less than the inside diameter of said outer shaft structure; said inner shaft structure being in mechanical communication with said outer shaft structure; said inner shaft structure having an axial tension generated by a biasing means in which said axial tension upon said inner shaft structure induces a stiffness of said inner shaft structure; said stiffness of said inner shaft structure being mechanically conveyed to said outer shaft structure in order to effect an overall stiffness of said adjustable shaft structure. 
   
   
       2 . An adjustable shaft structure as in  claim 1  wherein said inner shaft structure is fastened, within said, outer shaft structure by a mechanical means. 
   
   
       3 . An adjustable shaft structure as in  claim 1  wherein said biasing means is comprised of a fluid. 
   
   
       4 . An adjustable shaft structure as in  claim 3 , wherein said fluid is pressurized by an apparatus to adjust said axial tension. 
   
   
       5 . An adjustable shaft structure as in  claim 4 , wherein said apparatus includes a piston. 
   
   
       6 . A shaft structure as in  claim 5 , wherein said apparatus includes a sleeve. 
   
   
       7 . A shaft structure as in  claim 1 , wherein indication of said, stiffness of said inner shaft structure and said outer shaft structure is annunciated. 
   
   
       8 . An adjustable shaft structure as in  claim 1 , wherein said shaft structure is connected to a golf club. 
   
   
       9 . An adjustable shaft structure as in  claim 1 , wherein said shaft structure is connected to a sports implement. 
   
   
       10 . A shaft structure having a configurable stiffness comprising in combination
 a first tube   a stiffening apparatus   
   
   
       11 . A shaft structure having a configurable stiffness as in  claim 10  wherein said stiffening apparatus is contained within said first tube and said, stiffening apparatus resistance to bending is mechanically conveyed to said first tube. 
   
   
       12 . A shaft structure having a configurable stiffness as in  claim 11  wherein said stiffening apparatus is comprised of all elongated chamber. 
   
   
       13 . A shaft structure having a configurable stiffness as in  claim 12  wherein said elongated chamber is filled with a fluid. 
   
   
       14 . A shaft structure having a configurable stiffness as in  claim 13  wherein said fluid is under compression. 
   
   
       15 . A shaft structure having a configurable stiffness as in  claim 14  wherein said compression is effected by a piston. 
   
   
       16 . A shaft structure having a configurable stiffness as in  claim 10  wherein said stiffness is indicated. 
   
   
       17 . A shaft structure being comprised of a plurality of nested tube structures wherein at least a first tube structure is contained within a second tube structure. 
   
   
       18 . A shaft structure as in  claim 17  wherein said first, tube structure has a characteristic of a first stiffness. 
   
   
       19 . A shaft structure as in  claim 17  wherein said second tube structure has a characteristic of a second stiffness. 
   
   
       20 . A shaft structure as in  claim 18  wherein said first stiffness of said first tube structure is generated by a stress that is applied to said first tube structure. 
   
   
       21 . A shaft structure as in  claim 20  wherein said stress is variable. 
   
   
       22 . A shaft structure as in  claim 20  wherein said stress is generated by an apparatus. 
   
   
       23 . A shaft structure as in  claim 22  wherein said apparatus is comprised of a piston and a sleeve wherein a seal is in communicative cooperation with said piston and said sleeve.