Abstract: A pneumatic door control equipped with a door control valve for operating a door drive to an open or a closed position. The door control valve has an opening and a closing solenoid-operated pilot valve and an opening and closing spool valve, each operable to a passage or a vent position. A shuttle valve is part of the control valve and works in conjunction with an operator-controlled emergency valve to vent both spool valves simultaneously. A differential pressure switch is connected to the door drive to sense abnormal pressure expended in a door-opening or closing movement. Such an occurrence will output a signal to an electronic switching device which also monitors, via limit switches, whether a door is fully opened or fully closed. If excess pressure occurs during a door-closing movement, the switching device will trigger the control valve to reverse to the opening position.

Abstract: An electropneumatic door valve for use with pneumatic door operations as are used on mass transit vehicles. The single valve housing arrangement provides either a through passageway or a throttled passageway for pressurizing the opening or closing chamber of a pneumatic door drive unit. Provisions are also made to allow automatic reversal should the door become wedged, and to allow manual override should that operation be desired. Electrical pulses initiated by the vehicle operator trigger one of two solenoid valves which direct one of two operating pistons into a position to dictate which passageway will be established. Three vent passageways are provided to exhaust compressed air from any of the chambers which had been charged during a previous door operation.

Abstract: Pressurization of closing and opening chambers of a door operator is controlled by first and second magnet valves coupled to the source of air. These valves are alternately energized by a switching network, e.g., a flip-flop, when sequentially actuated to close and open the door. The second magnet valve is biased to its vent position but the first valve is operated to its vent position by air through a double check valve when the second magnet valve is energized. Emergency and choke valves are inserted in series in the air supply to the magnet valves and normally pass air without restriction. Operation of the emergency valve, e.g., door blocked, shuts off air from the magnet valves and diverts that air to inhibit all output from the switching network and, through the check valve in opposite position, to operate the first magnet valve to vent position. Door operation is halted in position.