Abstract: A timing belt tensioner for a motor vehicle engine comprising a pivot that is fixed relative to the motor vehicle engine. A tensioner arm is mounted for pivotal movement on the pivot. The tensioner arm has a friction surface disposed in friction sliding relation with an adjacent surface during the pivotal movement. A belt engaging pulley is mounted for rotation on the tensioner arm. A spring coupled with the tensioner arm biases the arm in a direction tending to force the pulley into tensioning engagement with the belt when the tensioner is installed on the motor vehicle engine. The spring biasing the arm into a working position maintains a predetermined range of tension in the belt during dynamic operating equilibrium of the belt.

Abstract: A belt tensioner for tensioning a drive belt or timing belt comprises an eccentric adjusting member having an end surface thereof constructed and arranged to be mounted directly in surface-to-surface engagement with respect to a belt tensioner mounting surface for an engine frame. A pivoted structure is mounted on the eccentric adjusting member for pivoted movement between a first position and a second position, and a belt tensioning pulley is mounted for rotational movement on the pivoted structure.