One-piece shaft construction and a method of construction using bladder molding

Abstract

The present invention discloses a method of fabricating a composite material hockey stick shaft using internal bladder pressure molding technology. The bladder is inserted over a mandrel and composite materials are disposed on the bladder forming a soft, uncured piece. The mandrel is removed and the piece is disposed in a mold following which air pressure is applied to the bladder which deforms the piece to conform to the shape of the cavity. The addition of pressure and heat cures the composite materials and produces a finished hockey stick shaft.

I claim:  
     
         1 . A method of construction of a shaft made of composite materials comprising the steps of: 
 a. assembling a shaft portion from composite materials, wherein said composite materials are not cured, said shaft portion having opposed first and second extremities, said shaft portion comprising a hollow cavity disposed adjacent said first extremity, said hollow cavity being in fluid communication with said first extremity;    b. assembling a tenon made of composite materials, wherein said composite materials are not cured, said tenon having a hollow first end sized and configured to be mated with said first extremity of said shaft portion;    c. mating said hollow first end of said tenon with said first extremity of said shaft portion to form a joint;    d. applying internal pressure to said joint so as to bond said tenon to said shaft portion through the co-curing of said composite materials so as to form a unitary joint.    
     
     
         2 . The method of construction of  claim 1  wherein the application of pressure is effected through the introduction of a bladder inside said hollow cavity and said hollow first end prior to the mating thereof, said bladder being inflated such that it pressures the curing together of the composite material of said tenon and of said shaft portion.  
     
     
         3 . The method of construction of  claim 2  wherein prior to the application of said internal pressure to said bladder, said mated shaft portion and tenon are disposed inside a mold.  
     
     
         4 . The method of construction of  claim 1  wherein the composite materials of said shaft portion and of said tenon are not subjected to pressure prior to said mating.  
     
     
         5 . The method of construction of  claim 1  wherein said composite materials of said shaft portion and of said tenon are uncured prior to said mating.  
     
     
         6 . The method of construction of  claim 1  wherein said composite materials of said shaft portion and of said tenon are subjected to some pressure prior to mating.  
     
     
         7 . The method of construction of  claim 1  wherein the mating occurs through the insertion of said hollow first end of said tenon inside said first extremity of said shaft portion.  
     
     
         8 . The method of construction of  claim 1  wherein the mating occurs through the insertion of said first extremity of said shaft portion inside said first end of said tenon.  
     
     
         9 . The method of construction of  claim 2  wherein said bladder is internally disposed substantially along the whole length of said shaft and of said tenon.  
     
     
         10 . The method of construction of  claim 1  wherein said shaft is a shaft suitable for use with sporting equipment.  
     
     
         11 . The method of construction of  claim 10  wherein said shaft is a hockey stick shaft.  
     
     
         12 . A method of construction of a shaft comprising the steps of: 
 a. selecting a mandrel sized to correspond to the desired shape of the shaft;    b. disposing a bladder over the outside of said mandrel;    c. applying composite materials to the outside of said bladder;    d. removing said mandrel from the inside of said bladder, leaving behind said bladder and said composite materials applied therearound;    e. disposing said bladder and said composite materials in a mold;    f. applying air pressure to said bladder such that said bladder expands, forcing said composite materials to conform to the shape of said mold;    g. keeping said air pressure applied for a sufficient time so as to allow the curing of said composite materials to a rigid form.    
     
     
         13 . The method of construction of  claim 12  wherein said mold comprises a lower mold portion and an upper mold portion, wherein said bladder and said composite materials are disposed in said lower mold portion prior to the application of said air pressure, said upper mold portion being disposed over said lower mold portion so as to encase said bladder in said composite materials prior to the application of said air pressure to said bladder.  
     
     
         14 . The method of construction of  claim 12  wherein said mold is configured and sized so as to impart to said composite materials the shape of a hockey stick shaft.  
     
     
         15 . A method of construction of  claim 12  wherein the air pressure applied is in the range of 0 to 200 P.S.I.  
     
     
         16 . The method of construction of  claim 15  wherein the air pressure is applied in a smooth, continuous gradient up to its required pressure.  
     
     
         17 . The method of construction of  claim 15  wherein the air pressure is applied in an initial rapid burst up to the desired pressure and then maintained for the duration of the curing.  
     
     
         18 . The method of construction of  claim 15  wherein heat is applied to the mold during the curing of said composite materials.  
     
     
         19 . The method of construction of  claim 15  wherein the mold is heated prior to the introduction of said bladder and said composite materials and wherein the heat of the mold is increased during said curing.  
     
     
         20 . The method of construction of  claim 15  wherein said bladder is made from a group of materials comprising nylon, silicone, rubber and latex.  
     
     
         21 . The method of construction of  claim 15  wherein said composite materials are selected from a group comprising carbon fibers, fiberglass, Kevlar™ and viscoelastic films.  
     
     
         22 . The method of construction of  claim 15  wherein the mold comprises a mold cavity which cavity comprises opposed, spaced apart, top and bottom surfaces, and opposed left and right surfaces spacing apart said top and bottom surfaces.  
     
     
         23 . The method of construction of  claim 22  wherein said top and bottom surfaces are flat.  
     
     
         24 . The method of construction of  claim 22  wherein said top and bottom surfaces are parallel to each other.  
     
     
         25 . The method of construction of  claim 22  wherein one or more of said top surface, bottom surface, left surface and right surface is curved.  
     
     
         26 . The method of construction of  claim 15  wherein said left and right surfaces are parallel to each other for a portion of the mold cavity and converge to a narrower point adjacent to one extremity thereof.  
     
     
         27 . A shaft constructed using the method of construction of  claim 15 .  
     
     
         28 . The shaft of  claim 27  wherein said shaft is a hockey stick shaft.