Patent ID: 7682273

Claim:
An automotive power transmission chain subject to fluctuating loads, comprising a chain operable over a range of engine speeds when drivingly engaged to a sprocket, the chain having a plurality of sets of links, 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 rocker joints, the rocker joints including a long rocker pin and a short rocker pin, the long rocker pin extending completely through an aperture to join one outermost link to the opposite outermost link of a given set, and the short rocker pin extending partly, but not completely, through the same aperture, such that the short rocker pin and long rocker pin in the aperture are operable to rock against each other, the short rocker pins comprising toughened ceramic material effective to reduce the elongation of the chain by at least about 10% after 50 hours of operation with an internal combustion engine subjecting the chain to at least 100 pounds of tension at 3250 rpm relative to the elongation of the chain with steel pivots.