Abstract: A winch for use with a van door opening system having separate opening and closing cables includes a two-section drum mounted on a common, motor-driven shaft. A helical spring is interposed between each drum section and the shaft, for compensating for differential extension of the opening and closing cables and for maintaining tension in the opening and closing cables. A driver is affixed to the shaft, and cooperates with a stop on the interior surface of each drum section, for providing a positive driving force for opening the door, and for closing the door. In operation, rotation of the shaft stores energy in the appropriate spring before the driver contacts a stop to provide a positive driving force, so that cable tension will be maintained when the motor-driven shaft is de-energized.

Abstract: An actuating mechanism for sliding doors provided on the passenger side of conventional panel-type trucks, commonly called vans, is intended to be either installed in the vehicle at the time of its original manufacture, or installed at any later time, without substantial modification of the vehicle. A winch assembly (44) including two separate winding drums (74, 86) on a common shaft (87) and driven by the shaft through springs (162, 174) and a positive driver (170), is mounted over the rear wheel well of such a vehicle. A guide assembly (50) including a pulley (54) and a pivoting guide member (62) is installed in an aperture cut in the door frame. A single pulley (56) is installed at the lower rear corner of the door opening, and a guide tube (58) is installed in the door. A flexible cable (52) is connected to an arm added to the latch operating mechanism, and extends through the guide tube (58), around the pulley (56), through the guiding assembly (50) to the winch assembly (44), for opening the door.