Ball bats with reduced durability regions for deterring alteration

Abstract

A ball bat includes a barrel wall with a composite laminate structure that includes an outwardly facing skin, an inwardly facing skin, a stack of composite laminate plies positioned between the outwardly facing skin and the inwardly facing skin, and a discontinuity in the stack forming a gap along a longitudinal axis of the bat. A rigid or semi-rigid appliance may be positioned in the gap. The appliance may be a ring element, which may have a cross-section that traverses the composite laminate plies in the stack in a direction that is perpendicular or oblique to the longitudinal axis of the bat. The cross-section of the ring element may be triangular. A second ring element may be positioned in the barrel wall. The second ring element may be connected to the other ring element with an adhesive bond or a connecting element.

What is claimed is: 
     
         1 . A ball bat comprising a handle and a barrel attached to or continuous with the handle along a longitudinal axis of the ball bat, the barrel having a barrel wall defining a hollow interior region of the barrel, wherein the barrel wall comprises:
 two stacks of composite laminate plies, wherein the two stacks are spaced apart from each other along the longitudinal axis to form a gap therebetween, wherein the gap extends to the hollow interior region of the barrel; and   an appliance positioned in the gap between the two stacks.   
     
     
         2 . The ball bat of  claim 1 , wherein the appliance is a ring element. 
     
     
         3 . The ball bat of  claim 2 , wherein the ring element comprises a plastic material or a composite material. 
     
     
         4 . The ball bat of  claim 2 , wherein a cross-section of the ring element is rectangular or square. 
     
     
         5 . The ball bat of  claim 2 , wherein a cross-section of the ring element comprises an axis that is oriented at an oblique angle relative to the longitudinal axis of the ball bat. 
     
     
         6 . The ball bat of  claim 2 , further comprising an inwardly facing skin positioned between the gap and the hollow interior region of the barrel to cover the gap. 
     
     
         7 . The ball bat of  claim 1 , wherein the appliance is exposed to the hollow interior region of the barrel. 
     
     
         8 . The ball bat of  claim 1 , wherein the appliance is unbonded to the two stacks. 
     
     
         9 . A ball bat comprising a barrel, wherein the barrel comprises:
 a stack of composite laminate plies, wherein the stack has a thickness along a radial direction perpendicular to a longitudinal axis of the ball bat;   a discontinuity in the stack, the discontinuity forming a gap extending along a direction transverse to the longitudinal axis of the bat;   a ring element positioned in the gap; and   an inwardly facing skin positioned between the gap and a hollow interior region of the barrel, wherein the gap extends to the inwardly facing skin.   
     
     
         10 . The ball bat of  claim 9 , wherein the ring element comprises a plastic material or a composite material. 
     
     
         11 . The ball bat of  claim 9 , wherein a cross-section of the ring element comprises an axis that is oriented at an oblique angle relative to the longitudinal axis of the ball bat. 
     
     
         12 . The ball bat of  claim 9 , wherein a cross-section of the ring element is rectangular or square. 
     
     
         13 . The ball bat of  claim 9 , wherein the ring element is unbonded to the stack. 
     
     
         14 . A ball bat comprising a handle and a barrel attached to or continuous with the handle along a longitudinal axis of the ball bat, wherein the barrel comprises a reduced-durability region, and wherein the reduced-durability region includes:
 two stacks of composite laminate plies, wherein the two stacks are spaced apart from each other along the longitudinal axis to form a gap therebetween, wherein the gap encircles the longitudinal axis of the ball bat;   an inwardly facing skin positioned between a ply of a first one of the two stacks and a hollow interior region of the barrel; and   an appliance positioned in the gap between the two stacks.   
     
     
         15 . The ball bat of  claim 14 , wherein the inwardly facing skin is positioned between the gap and the hollow interior region of the barrel to cover at least part of the gap. 
     
     
         16 . The ball bat of  claim 14 , wherein the gap is a first gap, and wherein:
 the inwardly facing skin comprises a discontinuity forming a second gap along the longitudinal axis;   the first gap and the second gap are connected to each other; and   the ball bat further comprises a cover layer positioned over the second gap.   
     
     
         17 . The ball bat of  claim 14 , further comprising an outwardly facing skin forming an exterior surface of the barrel. 
     
     
         18 . A ball bat comprising:
 a handle; and   a barrel attached to or continuous with the handle along a longitudinal axis of the ball bat, wherein the barrel comprises a reduced-durability region;   wherein the reduced-durability region includes:
 two stacks of composite laminate plies, wherein the two stacks are spaced apart from each other along the longitudinal axis to form a gap therebetween; 
 a ring element positioned in the gap between the two stacks; and 
 an inwardly facing skin positioned between the ring element and a hollow interior region of the barrel. 
   
     
     
         19 . The ball bat of  claim 18 , wherein the ring element comprises a plastic material or a composite material. 
     
     
         20 . The ball bat of  claim 18 , wherein a cross-section of the ring element is rectangular or square. 
     
     
         21 . The ball bat of  claim 18 , wherein the ring element is unbonded to the two stacks. 
     
     
         22 . The ball bat of  claim 18 , further comprising an outwardly facing skin positioned over a radially outward ply in one of the two stacks to form an exterior surface of the barrel.