Abstract: An actuation device for motor vehicle parts that are movable by an electric motor, in particular for window regulators and sliding roofs that are driven by a reversible electric motor. This actuation device has a setpoint value device for the desired position of the movable part, an incremental actual-value device for producing a signal corresponding to the actual position of the movable part, an absolute actual value device which emits first and second signals that are positionally fixed relative to the incremental actual-value device, and a microprocessor to compare the setpoint and actual value signals and to perform control and regulation programs. The signal emitted by the absolute actual-value device changes only at predetermined position values and the absolute actual-value device has position zones which are separated from one another by these position values that can be predetermined. The first and last position zones are each defined by a first or second end position of the movable part.

Abstract: Drive device for closing parts in motor vehicles, especially sliding roofs, sliding/lifting roofs, and the like, with a drive motor, a sensor for determining the actual rpm of the drive motor and a clamping protection means for disengaging or for reversing the direction of rotation of the drive motor when the danger of clamping of the closing parts arises. The device has a speed controller which delivers an actuating signal which is a function of the deviation of the actual speed from a set speed of the drive motor. The drive device also includes an actuating means for varying the supply voltage delivered to the drive motor depending on the actuating signal of the speed controller, and an evaluation means which triggers the clamping protection means and which determines the existence of incipient clamping based on a signal which is dependent on the actuating signal of the speed controller.