Patent ID: 8052559

Claim:
A tensioner for a continuous loop power transmission system of an internal combustion engine, the continuous loop consisting of a chain having a first strand and a second strand, each strand located between a drive sprocket connected to a driveshaft and at least one driven sprocket connected to at least one camshaft, comprising: a) a first tensioning arm having a first end, a second end for pivotally mounting to the engine and a chain sliding surface operatively engaging the first strand of chain; b) a second tensioning arm having a first end, a second end for pivotally mounting to the engine and a chain sliding surface operatively engaged with the second strand of chain, c) a two way damper comprising: i) a relatively planar upper tensioner yoke having a center, a first end and a second end, ii) a relatively planar lower tensioner yoke having a center, a first end and a second end, the upper tensioner yoke and the lower tensioner yoke being disposed relatively coplanar to and spaced apart from each other by a first yoke pin coupling the first end of the upper tensioner yoke and the first end of the lower tensioner yoke and a second yoke pin coupling the second end of the upper tensioner yoke and the second end of the lower tensioner yoke; iii) a center bushing stack comprising: A) a center bushing passing through the center of the upper tensioner yoke and the center of the lower tensioner yoke, having a center bore for receiving a mounting pin, an upper flange contacting an upper surface of the upper tensioner yoke and a lower flange contacting a lower surface of the lower tensioner yoke; B) a Belleville spring surrounding the center bushing; C) an upper spring bushing surrounding the center bushing, on an upper side of the Belleville spring; and D) a lower spring bushing surrounding the center bushing, on a lower side of the Belleville spring; iv) a torsion spring surrounding the Belleville spring comprising a first leg abutting one of the yoke pins and a second leg for coupling to the internal combustion engine; and d) a first linkage coupling the first yoke pin to the first tensioning arm and a second linkage coupling the second yoke pin to the second tensioning arm; such that when installed upon an engine the torsion spring imparts a biased torque, creating a pivotal motion of the two-way damper about the center bushing, causing the first linkage and the second linkage to move laterally to draw the first tensioning arm and the second tensioning arm inward to apply tension to the first strand and the second strand of the chain; and wherein compression of the center bushing stack by tightening the mounting pin creates a drag which resists the pivotal motion, between the upper flange of the center bushing with the upper tensioner yoke and the lower flange of the center bushing with the lower tensioner yoke.