Patent ID: 7628719

Claim:
A tensioner for imparting tension to a chain of a closed loop power transmission system of an internal combustion engine comprising: a) a first elongated tensioning arm having a first end and a second end, the first elongated tensioning arm positioned in operative engagement with a first strand of the chain, the first elongated tensioning arm pivotally secured to a first mounting means on the engine; b) a second elongated tensioning arm having a first end and a second end, the second elongated tensioning arm positioned in operative engagement with a second strand of the chain, the second elongated tensioning arm pivotally secured to a second mounting means on the engine; and c) an adjusting arm having a first end and a second end and a ratcheting means located substantially equidistant between the first end and the second end; wherein the first end of the adjusting arm is pivotally attached to the second end of the first elongated tensioning arm and the second end of the adjusting arm is pivotally attached to the second end of the second elongated tensioning arm; the adjusting arm having two pairs of elongated straps, each elongated strap having a first end and a second end, wherein the first ends of the first pair of straps form the first end of the adjusting arm, the first ends of the second pair of straps form the second end of the adjusting arm, the second ends of the first pair of straps form a seat to retain a first end of a coil spring and the second ends of the second pair of straps form a seat to retain a second end of the coil spring and a first rack of teeth on an inner surface of each of the first pair of straps proximal to the second ends of each of the first pair of straps and a second rack of teeth on an outer surface of each of the second pair of straps proximal to the second ends of each of the second pair of straps whereby the adjusting arm responds to an increase in slack or excessive wear conditions of the chain; and further wherein each first rack of teeth meshes with the second rack of teeth to create a unidirectional no-return ratcheting means.