Provided in a device for activating a wheel brake of a vehicle, having a tensioning installation which has a spindle drive, are two electric motors, the first electric motor by way of a first gear mechanism acting bi-directionally on the spindle drive. In order for the position of the tensioning installation, once attained, to be fixed in a parking brake, a second electric motor by way of a second gear mechanism, which has a self-locking worm gear mechanism and by way of at least one releasable coupling that acts uni-directionally in the activating direction, is coupled to the spindle drive. The coupling is composed of a cam on an output shaft of the first gear mechanism, and a pin on an output element of the worm gear mechanism. Since the cam cannot be reversed beyond the pin, a latching position of the tensioning installation is defined in this way.

The releases of an electromechanical parking brake are controlled by measuring the change in the intensity (I) of the electrical current provided to the control motor, or a function derived from this intensity, and by extending the release of the brake only for a determined duration (t) after stabilization of this intensity, in order not to unnecessarily increase the idle travel of the brake actuator nor to extend the duration of the control. The determined duration (t) also depends on the temperature and on the hydraulic pressure in the brake.