Power transmission belt

Abstract

The invention comprises a multi-ribbed belt having a tensile cord. The tensile cord having areas of opposite twist along a length of a single cord. In particular, a tensile cord comprises S twist sections and Z twist sections. An S twist section is separated from a Z twist section by a node, thereby creating alternate S twist and Z twist sections along a length of a tensile cord. Therefore, the inventive belt comprises a belt having a tensile cord having a random distribution of S twist sections and Z twist sections along a length of the belt as well as across a width of the belt. This significantly reduces tracking force while using only a single cord in belt construction.

I claim:  
     
         1 . A belt comprising: 
 an elastomeric body;    a tensile cord embedded in the elastomeric body in an endless direction; and    the tensile cord having alternate Z twist sections and S twist sections along a length of the tensile cord.    
     
     
         2 . The belt as in  claim 1  further comprising: 
 the S twist section having a length;  
 the Z twist section having a length; and  
 the S twist section length is not coextensive with the Z twist section length.  
 
     
     
         3 . The belt as in  claim 1  wherein: 
 each of the S twist sections and Z twist sections are randomly distributed across a width of the belt.  
 
     
     
         4 . The belt as in  claim 1  further comprising a profile.  
     
     
         5 . The belt as in  claim 4 , wherein the profile comprises a multi-ribbed profile.  
     
     
         6 . The belt as in  claim 1 , wherein each S twist section and 
 Z twist section comprise unequal lengths.    
     
     
         7 . The belt as in  claim 1 , wherein the tensile cord comprises: 
 a Z twist comprised of at least two strands, each of the strands having an S twist.