Einrichtung zum Spannen eines Endlos-Transmissionselements

The description refers to a device for clamping an endless transmission element such as a belt, a toothed belt or a chain of a drive unit, comprising a roller which contacts the transmission element and which has a rocker bearing which is applied against a spring in the direction of the transmission element. The invention is characterized by the fact that a blocking unit is provided to prevent the rocker from performing a return stroke.