Abstract: A limiting value (G1; G2) of the speed (n) or of the duration of rotation (t) of an actuator drive shaft is used to provide effective protection against a closing part pinning an obstruction, by either switching off or reversing the actuator drive of the closing part. This limiting value (G1; G2) is defined from the speed (n) or duration of rotation (t) determined for each position of the travel path (h), and from a multiplier which represents the relative sluggishness (S1/S2) of the respective actuator in the respective position along the travel path. The limiting value (G1; G2) is updated in conformance with actual operation of the actuator drive.