US Patent 7163478 Belt tensioner having an automatically adjustable travel stop

A tensioner for generating tension in a power-transmitting belt is provided. The tensioner includes a base, which may be secured to an engine, and an arm that is movably attached to the base. A pulley is rotatably attached to the arm for engaging the belt. A spring is operatively connected to the arm and the base for urging the arm to move relative to the base in a first direction. When the arm is moved in the first direction, the pulley is moved into engagement with the belt with a force to tension the belt. The tensioner further includes a stop that is adjustably positioned on the base to limit the movement of the arm in a second direction. The position of the stop on the base may be automatically adjusted by the spring during installation of the tensioner.