Multi-ribbed power transmission belt and method of making said belt

A multi-ribbed transmission belt for use with multi-grooved pulleys, said belt having a longitudinally extending continuous singular body of an integral unitary construction comprising:

• A. a first portion in cross-section being of generally rectangular configuration with one face thereof forming the top surface of the belt;
• B. a second portion adjacent to said first portion and being a non-separately attached continuation thereof, said second portion having one face defining the bottom surface of the belt and including:
• a plurality of power-transmitting ribs with each rib having at least one stress-resisting member embedded therein with said member extending longitudinally of the belt and disposed across the width of the rib, the member in one said rib being aligned with the member in an adjacent rib so that the distance between the top surface of said first portion and a horizontal plane through all of the members in all of the ribs is substantially equal, each rib having a cross-sectional configuration adapted to conform to a groove of the pulley;
• and a groove provided between each adjacent rib penetrating from the bottom surface of said second portion through the horizontal plane of said stress-resisting members and terminating at substantially the interface of said first and second portion to provide a clearance gap for passage of the belt over the pulley thereby allowing a complete wedging action of each said rib in its corresponding pulley groove.

In a belt drive assembly including the combination of a belt of flexible resilient material having a plurality of ribs of generally trapezoidal cross-section with a plurality of grooves therebetween and a pair of grooved pulleys around which the belt is applied with each rib of said belt engaging a groove of said pulleys, said belt comprising a continuous singular body having two opposite surfaces which are equally spaced apart throughout the continuous length thereof, said body comprising a primary tension section adjacent to one surface of the body having a continuing part thereof extending transversely across the entire width of the belt and a plurality of parallel power transmitting V-ribs extending longitudinally of the belt and downwardly from said continuing part of the primary tension section and constituting a non-separately attached continuum thereof, the grooves between the ribs terminating at said continuing part of the primary tension section, each said rib including an individual tension section, compression section and neutral axis between the tension and compression sections, each said neutral axis including at least one stress-resisting layer therein and said ribs being spaced to engage the grooves of the pulley in driving relation, the configuration of the belt grooves between the primary tension section and a horizontal plane through said stress-resisting layer providing a clearance area for passage of the belt over the ribs of the pulley to allow individual wedging action of each rib in a corresponding pulley groove.