A reversible conveyor belt system has, on at least one surface of the belt, projections arranged preferable in a plurality of asymmetrical rows and columns thereby forming a matrix engagable with an offset mating tracking surface glued to the surface of the pulley. The projections are truncated geometrical...http://www.google.com.au/patents/US5630500?utm_source=gb-gplus-sharePatent US5630500 - Positive geared tracking pulley and belt for a reversible conveyor belt system
