Patent ID: 8066600

Claim:
A ratcheting tensioner for a closed loop chain driven power transmission system of an internal combustion engine comprising: a) a base tensioner arm pivotally mounted to the engine having an inner edge with a chain sliding surface to operatively engage one strand of the chain and an outer edge, b) an adjusting tensioner arm mounted to the engine having an inner edge with a chain sliding surface to operatively engage a second strand of the chain and an outer edge, c) a link plate having a first edge and a second edge, the link plate being pivotally secured to the base tensioner arm in proximity to the first edge by a torsional pivot mount; d) a ratchet located in proximity to the second edge of the link plate comprising a longitudinally shaped channel having a centerline, a length, an inner side wall and an outer side wall, wherein the centerline of the channel is positioned approximately 5 to 15 degrees from a perpendicular of an imaginary line between an axis of the torsional pivot mount and the centerline of the channel; and e) a ratchet pin secured to the adjusting tensioner arm which traverses in only one direction along the length of the channel as the link plate pivots in response to a torsional force supplied by the torsional pivot mount, wherein when slack in the chain progressively increases due to the wearing of components of the closed loop power transmission system, the ratchet pin traverses through the channel such that the movement of the ratchet pin through the channel urges the base tensioning arm and the adjusting tensioning arm to progressively move toward each other.