American football with thin cover

Abstract

A football is provided with a thinner cover than conventional footballs. The thickness of the cover is less than 1.25 mm. The cover is formed from four cover panels. Each cover panel is stitched to a liner panel to form four panel assemblies. The liner panels are stronger and more resistant to bending than conventional liner panels. The panel assemblies are stitched together to form the seams of the football. An inflatable bladder is inserted inside of the attached panel assemblies. The liner panels withstand most of the forces on the football which are created by the internal bladder pressure and by impacts. The relatively thin cover panels are not required to support significant loads.

We claim:  
     
         1 . A football comprising: 
 an inflatable bladder,    a liner surrounding the bladder, the liner having a tensile strength of at least 5500 psi, and    a cover attached to the liner, the cover having a thickness of less than 1.25 mm.    
     
     
         2 . The football of  claim 1  in which the liner has a drape angle of less than 30 degrees.  
     
     
         3 . The football of  claim 1  in which the cover is leather.  
     
     
         4 . The football of  claim 1  in which the liner includes a fabric layer and a polymeric layer which is bonded to the fabric layer.  
     
     
         5 . The football of  claim 4  in which the polymeric layer is rubber.  
     
     
         6 . The football of  claim 1  in which the cover has a tensile strength of at least 4000 psi.  
     
     
         7 . The football of  claim 1  in which the cover has a thickness of 0.80 mm or less.  
     
     
         8 . The football of  claim 1  in which the thickness of the liner is at least 0.70 mm.  
     
     
         9 . The football of  claim 1  in which the football includes a pair of ends and a longitudinal centerline which extends between the ends and the liner includes four liner panels and the cover includes four cover panels, the liner panels and the cover panels being stitched together along four seams which extend between the ends, transverse cross sections of the football through the seams and the longitudinal centerline having a configuration between each pair of adjacent seams which lies closer to a straight line between the adjacent seams than to an arc of a circle between the seams.  
     
     
         10 . A football comprising: 
 an inflatable bladder,    a liner surrounding the bladder, the liner having a drape angle of less than 30 degrees, and    a cover attached to the liner, the cover having a thickness of less than 1.25 mm.    
     
     
         11 . The football of  claim 10  in which the liner includes a fabric layer and a polymeric layer which is bonded to the fabric layer.  
     
     
         12 . The football of  claim 11  in which the polymeric layer is rubber.  
     
     
         13 . The football of  claim 10  in which the cover has a tensile strength of at least 4000 psi.  
     
     
         14 . The football of  claim 10  in which the cover has a thickness of 0.80 mm or less.  
     
     
         15 . The football of  claim 10  in which the thickness of the liner is at least 0.70 mm.  
     
     
         16 . The football of  claim 10  in which the football includes a pair of ends and a longitudinal centerline which extends between the ends and the liner includes four liner panels and the cover includes four cover panels, the liner panels and the cover panels being stitched together along four seams which extend between the ends, transverse cross sections of the football through the seams and the longitudinal centerline having a configuration between each pair of adjacent seams which lies closer to a straight line between the adjacent seams than to an arc of a circle between the seams.  
     
     
         17 . The football of  claim 10  wherein the cover is made of a material selected from the group consisting of a natural leather and a synthetic leather.