Patent ID: 7362040

Claim:
A device for opening and closing an opening ( 11 ) in a motor vehicle, by means of a motor-driven, movable part ( 10 ), with a control unit ( 26 ) and a pinch prevention sensor ( 14 ), which is disposed essentially along an edge ( 20 ) of the part ( 10 ) and/or of a frame profile ( 12 ) bordering the opening ( 11 ) and which, during the closing of the part ( 10 ), detects an obstacle ( 24 ) that is in the movement path of the part ( 10 ) and sends a signal to the control unit ( 26 ) in order to stop or reverse the movement of the part ( 10 ), wherein the pinch prevention sensor ( 14 ) has a highly elastic, electroactive polymer (EAR) material ( 30 ) disposed between electrodes ( 28 , 34 , 36 ), which produces a voltage change in the electrodes ( 28 , 34 , 36 ) in the event of a deformation, wherein a voltage U according to the formula U=t* (p/ε r *ε 0 )½ occurs in the electrodes ( 28 , 34 , 36 ), where t is the thickness ( 38 ) of the EAR layer ( 30 ), ε r is the specific inductive capacity, ε 0 is the electric constant, and P is the pressure on the EAP layer ( 30 ) generated by the obstacle ( 24 ).