US Patent 7217206 Active tensioner

An automatic tensioner having a load cell for detecting and controlling a power transmission belt tension. The tensioner comprises a lead screw driven by an electric motor for setting a lever arm/pulley position and thereby a belt load. The tensioner also comprises a load cell engaged with a tensioner lead screw for detecting a belt load. The tensioner motor is controlled loop using a load cell signal. The controller compares a detected belt load from the load cell with a predetermined belt load value to identify a desired belt load and thereby set a tensioner lever arm position corresponding to said desired belt load. The tensioner may also be controlled by an engine operating condition.