U.S. Pat. No. 4,721,498 discloses an endless elastomeric drive belt designed to minimize lateral shifting having a first ply of wire cable reinforcement substantially parallel to the longitudinal direction of the belt, a second ply of wire cable reinforcement laid at a bias angle and a third ply of wire cable reinforcement laid at a bias angle. The angle of the third ply cables is larger than that of the second ply in order that the lateral force components of the outer two plies balance each other when being bent around a wheel. Alternatively, the patent discloses a belt with the two outer plies being laid at equal and opposite bias angles, however, the two plies are constructed differently with the third ply having fewer ends than the second ply either by having smaller cables or a less number of cables, again to balance the lateral forces exerted by the outer two plies. Producing two plies of different construction is inefficient, costly and can lead to difficulties should they be mistakenly interchanged in a manufacturing operation.
U.S. Pat. No. 5,211,609 discloses an endless elastomeric belt designed to minimize lateral shifting, having a spirally wound wire cable reinforcement, a first bias ply of wire reinforcement laid at an angle which has the same direction as the spirally wound first cable and a second bias ply of wire reinforcement laid at an opposite but equal angle to the first bias wire reinforcement. The second bias ply of wire cable reinforcement is spaced at a distance from the first spiral wire cable reinforcement so as to neutralize the lateral forces generated, while in use, of the entire elastomeric drive belt.
USPTO Backgrounds
USPTO Backgrounds