Swing weight plug and method for manufacturing a golf club having a pre-selected swing weight

Abstract

A plug for use in a golf club to selectively alter the swing weight of the golf club includes a sleeve for holding a high-density material such as Tungsten (sintered or unsintered) in the form of powder, rods or scrap parts. The sleeve is preferably made of plastic and shaped as a substantially hollow cylinder having an outer wall surface. The sleeve is further formed with a plurality of elongated ridges that project from the outer wall surface of the cylindrical sleeve. The ridges define a ridge diameter measured around the radial extremity of each ridge. This ridge diameter is sized to be larger than the inner diameter of the shaft at the end where the plug will be inserted. When the sleeve is inserted into the shaft, the ridges are compressed to establish an interference fit between the ridges and the shaft that anchors the sleeve to the shaft.

What is claimed is:  
     
         1 . A plug assembly for increasing the swing weight of a golf club having a shaft, the shaft being hollow and having a first end and a second end, said plug assembly comprising: 
 a sleeve for insertion into an end of said hollow shaft, said sleeve formed with a cavity;    a high density material disposed in said cavity; and    a means for attaching said sleeve to the shaft of the golf club for movement therewith.    
     
     
         2 . A plug assembly as recited in  claim 1  wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said attaching means comprises a plurality of ridges formed on said sleeve with each said ridge extending from said outer wall surface of said sleeve to contact said shaft and create an interference fit between said sleeve and said shaft to attach said sleeve to said shaft.  
     
     
         3 . A plug assembly as recited in  claim 2  wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.  
     
     
         4 . A plug assembly as recited in  claim 2  wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge extends substantially helically about said longitudinal axis on said outer wall surface.  
     
     
         5 . A plug assembly as recited in  claim 1  wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said attaching means comprises an adhesive material for bonding said outer wall surface of said sleeve to said shaft.  
     
     
         6 . A plug assembly as recited in  claim 1  wherein said sleeve is made of a plastic material.  
     
     
         7 . A plug assembly as recited in  claim 1  wherein said high-density material comprises a metal.  
     
     
         8 . A plug assembly as recited in  claim 1  wherein said high-density material is selected from the group consisting of Tungsten powder, sintered Tungsten rod, sintered Tungsten scrap parts, steel, stainless-steel, copper, brass, lead, and lead alloy.  
     
     
         9 . A plug assembly as recited in  claim 1  wherein said plug assembly weighs between approximately one gram (1 gm) and thirty grams (30 gms).  
     
     
         10 . A golf club having a pre-selected swing weight, said golf club comprising: 
 a head;    a hollow golf shaft having a grip end and a head end;    a sleeve for insertion into said head end of said hollow shaft, said sleeve formed with a cavity;    a high density material disposed in said cavity;    a means for attaching said sleeve to said shaft for movement therewith; and    a means for affixing said head to said shaft at said shaft end.    
     
     
         11 . A golf club as recited in  claim 10  wherein said sleeve is substantially cylindrically shaped defining a longitudinal axis and is formed with an outer wall surface having diameter (D 1 ), and wherein said shaft has an inner diameter (D 2 ) at said head end, and further wherein said attaching means comprises a plurality of ridges formed on said sleeve with each said ridge extending from said outer wall surface of said sleeve to a ridge diameter (D 3 ), and wherein said sleeve and said ridges are sized relative to said shaft with D 1 <D 2 <D 3  to create an interference fit between said sleeve and said shaft when said sleeve in inserted in said shaft and to allow air from said head to pass between said outer surface and said shaft after said sleeve is attached to said shaft.  
     
     
         12 . A golf club as recited in  claim 11  wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.  
     
     
         13 . A golf club as recited in  claim 11  wherein said sleeve has a first end for insertion into said shaft and a second end, said sleeve being formed with a flange at said second end and having a plurality of spacers to maintain said flange at a preselected distance from said head end of said shaft after said sleeve is attached to said shaft.  
     
     
         14 . A golf club as recited in  claim 11  wherein said plurality of spacers are spaced apart around said sleeve and said flange is substantially cylindrical having a diameter (D 4 ) and said head is formed with a hosel bore having a diameter (D 5 ) with said flange sized relative to said hosel bore wherein D 4 <D 5  to allow air from said head to pass around said flange, between said spacers and between said outer surface and said shaft during insertion of said shaft and said sleeve into said hosel bore.  
     
     
         15 . A golf club as recited in  claim 11  wherein said affixing means comprises a pin formed on said head for insertion into said head end of said shaft.  
     
     
         16 . A method for preparing a golf club having a pre-selected swing weight, said method comprising the steps of: 
 providing a head;    providing a hollow golf shaft having a grip end and a head end;    providing a sleeve formed with a cavity;    disposing a high density material in said cavity;    inserting said sleeve into said head end of said hollow shaft to attach said sleeve to said shaft for movement therewith; and    affixing said head to said shaft at said shaft end.    
     
     
         17 . A method as recited in  claim 16  wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said sleeve is formed with a plurality of ridges with each said ridge extending from said outer wall surface of said sleeve to contact said shaft and create an interference fit between said sleeve and said shaft to attach said sleeve to said shaft.  
     
     
         18 . A method as recited in  claim 17  wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.  
     
     
         19 . A method as recited in  claim 17  wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge extends helically about said longitudinal axis on said outer wall surface.  
     
     
         20 . A method as recited in  claim 16  wherein said high-density material comprises Tungsten.  
     
     
         21 . An assembly for increasing the swing weight of a golf club having a shaft, the shaft being hollow and having a first end and a second end, said plug assembly comprising: 
 a plug for insertion into an end of said hollow shaft, said plug comprising a polymeric constituent having a density, ρ 1 , and a high density constituent having a density, ρ 2 , with ρ 2 >ρ 1 ; and    a means for attaching said plug to the shaft of the golf club for movement therewith.    
     
     
         22 . An assembly as recited in  claim 21  wherein said plug is made from a mixture comprising said polymeric constituent filled with said high density constituent.  
     
     
         23 . An assembly as recited in  claim 21  wherein said plug is made from a mixture of said polymeric constituent filled with secondary Tungsten powder having spheroidal grains.  
     
     
         24 . An assembly as recited in  claim 23  wherein said secondary Tungsten powder has a tap powder density between approximately ten grams per cubic centimeter (10 g/cc) and approximately twelve grams per cubic centimeter (12 g/cc).