Patent ID: 7201687

Claim:
An automotive power transmission chain and sprocket drive subject to fluctuating loads, comprising: a drive sprocket having sprocket teeth, and a chain operable over a range of speeds and the drive sprocket is effective for putting the chain under a tension of at least 100 pounds at 3250 rpm, the chain comprised of a plurality of sets of links operatively engaging said sprocket teeth, and pivots joining successive sets of the links to permit articulation of each set of links relative to adjacent sets of links, the pivots comprise ceramic material effective to reduce the elongation of the chain by at least about 10% relative to the elongation of the chain with steel pivots when the chains are subjected to a tension of 100 pounds for ten hours at 3250 rpm, and the ceramic material is selected from the group consisting of toughened alumina, alumina/zirconia composites, alumina/zirconia composites incorporating a rare earth oxide, composites having a metastable tetragonal zirconia crystal content, stabilized zirconia, beryllia, sapphire, and combinations thereof.