Ball bat with a fused end cap

Abstract

A ball bat includes an end cap that is fused directly or indirectly to an inner or outer surface of the bat barrel. In one embodiment, a sleeve is molded or bonded to an inner surface or an outer surface of the bat barrel. The end cap is then fused to the sleeve, optionally via a spin-welding process. If removal of the end cap is attempted, a fracture zone results that damages the end cap and makes it unusable and effectively irreplaceable.

What is claimed is: 
     
         1 . A ball bat, comprising:
 a handle;   a barrel attached to or integral with the handle;   a sleeve attached to or integral with a surface of the barrel; and   an end cap positioned at an end of the barrel and fused to the sleeve.   
     
     
         2 . The ball bat of  claim 1  wherein the end cap and the sleeve comprise substantially similar materials such that they are fusible to each other. 
     
     
         3 . The ball bat of  claim 2  wherein the end cap and the sleeve each comprise thermoplastic materials. 
     
     
         4 . The ball bat of  claim 3  wherein the barrel comprises a composite material, and the thermoplastic sleeve is molded or bonded to an inner surface of the composite barrel. 
     
     
         5 . The ball bat of  claim 3  wherein the barrel comprises a composite material, and the thermoplastic sleeve is molded or bonded to an outer surface of the composite barrel. 
     
     
         6 . The ball bat of  claim 1  wherein the end cap is fused to an inner surface of the sleeve. 
     
     
         7 . The ball bat of  claim 1  wherein the end cap is fused to outer surface of the sleeve. 
     
     
         8 . The ball bat of  claim 1  wherein the sleeve is injection-molded to the inner surface of the barrel. 
     
     
         9 . The ball bat of  claim 8  wherein one of the sleeve and the inner surface of the barrel includes a protrusion, and the other of the sleeve and the inner surface of the barrel includes a corresponding groove into which the protrusion is positioned to mechanically secure the sleeve to the inner surface of the barrel. 
     
     
         10 . The ball bat of  claim 1  wherein one of the sleeve and the surface of the barrel includes a protrusion, and the other of the sleeve and the surface of the barrel includes a corresponding groove into which the protrusion is positioned to mechanically secure the sleeve to the surface of the barrel. 
     
     
         11 . A ball bat, comprising:
 a handle;   a barrel including a first end attached to or integral with the handle and a second distal end, with the barrel including an inwardly projecting rim at the second distal end and an inwardly projecting forming portion spaced from the rim to define a cavity between the rim and the forming portion; and   an end cap including a deformable extension positioned in the cavity under the rim such that the end cap is secured to the barrel.   
     
     
         12 . The ball bat of  claim 11  wherein the barrel comprises a metal material and the end cap comprises a deformable material. 
     
     
         13 . The ball bat of  claim 12  wherein the end cap comprises a thermoplastic material. 
     
     
         14 . The ball bat of  claim 11  wherein the forming portion includes a curved portion that positions the deformable extension in the cavity. 
     
     
         15 . A method of attaching an end cap to a barrel of a ball bat, comprising:
 attaching a sleeve to an inner surface of the barrel;   spinning the end cap at a high velocity;   inserting the spinning end cap into the barrel so that an outer region of the end cap spins against an inner surface of the sleeve; and   fusing the outer region of the end cap to the sleeve via the heat and friction generated between them.   
     
     
         16 . The method of  claim 15  wherein the attaching step comprises molding the sleeve to the inner surface of the barrel. 
     
     
         17 . The method of  claim 15  wherein the attaching step comprises bonding the sleeve to the inner surface of the barrel. 
     
     
         18 . The method of  claim 15  wherein the spinning step comprises spinning the end cap at a velocity of approximately 3000 rpm. 
     
     
         19 . The method of  claim 15  wherein the inserting step continues until a shoulder on the end cap contacts an end of the barrel. 
     
     
         20 . A ball bat, comprising:
 a handle;   a barrel attached to or integral with the handle, the barrel comprising a first fusible material; and   an end cap comprising a second fusible material that is compatible with the first fusible material, the end cap directly fused to the barrel.