Patent ID: 7942770

Claim:
A tensioner assembly for a drive system, including an endless drive element trained about at least two rotatable members, of an internal combustion engine, said tensioner assembly comprising: a hydraulic actuator operatively mountable to said engine, said hydraulic actuator having a piston moveable between retracted and extended positions in response to hydraulic pressure, and a spring urging said piston towards said extended position with a spring force that decreases as said piston moves towards said extended position; a guide having a first end pivotally mountable at a pivot point to said engine and a second end distal from said first end, said piston operatively engaging said second end of said guide to exert a torque on said guide to urge said guide into engagement with said endless drive element and maintain tension in said endless drive element; and a biasing assembly that engages said guide and applies a biasing assembly force on the guide at a perpendicular distance from the pivot point, wherein a biasing assembly torque is exerted by the biasing assembly on the guide based on the biasing assembly force and said perpendicular distance, wherein movement of said piston towards the extended position causes the biasing assembly to move in such a way that said perpendicular distance changes in such a way as to increase the biasing assembly torque thereby maintaining a generally uniform tension in said endless drive element.