Abstract: A tensioning device for maintaining a constant tension on continuous or endless drive members, such as continuous drive belts, chains and the like. A lever carries an idler roller at one end thereof which is adapted to engage the continuous drive belt, or the like. The lever is pivotally mounted on the engine, machine, or other apparatus which carries the continuous drive belt. A spring means is provided for normally biasing the lever in a direction to move the roller toward the belt to maintain a constant tension thereon. A spring biased wedge means is movably mounted on the lever for engagement with a cam means for holding the lever in an adjusted position. The spring biases the lever against the belt automatically to maintain a constant tension on the belt as the belt stretches or loses its tension. The wedge means permits the lever to automatically move in one direction to maintain a constant tension on the belt, but it restricts movement of the lever in the opposite direction.

Abstract: A constant tension apparatus for use on continuous or endless drive members, such as continuous drive belts, chains and the like. A lever arm carries an idler roller at one end thereof which is adapted to engage the continuous drive belt, or the like. The lever is pivotally mounted on a support bracket which in turn is mounted on an engine or other machine which carries the continuous drive belt. A spring means is provided for normally biasing the lever in a direction to move the roller toward the belt to maintain a constant tension thereon. A spring biased wedge means is movably mounted on the support bracket for holding the lever arm in an adjusted position. The spring biases the lever arm against the belt automatically to maintain a constant tension on the belt as the belt stretches or loses its tension. The wedge means permits the lever arm to automatically move in one direction to maintain a constant tension on the belt, but it restricts movement of the lever arm in the opposite direction.