Abstract: The invention relates to an operational arrangement for movable parts on vehicles, especially for hatches, movable roofs and the like. The invention provides for the automatic opening of the hatch or roof by a drive unit. The invention is characterized by placement of a drive mechanism within the vehicle, obviating the need for special coating of the drive mechanism, with transfer of forces from the interior to the exterior of the vehicle through a four joint hinge including a pivot pin which passes through the body of the vehicle and is operatively connected to the drive mechanism and the movable part.