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Electro-pneumatic door control apparatus

  • US 4,478,131 A
  • Filed: 08/24/1981
  • Issued: 10/23/1984
  • Est. Priority Date: 08/29/1980
  • Status: Expired due to Fees
First Claim
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1. An electro-pneumatic door control apparatus for use on public vehicles for effecting reversal of door movement in the event of an obstruction in the path of movement of the door, said door control apparatus comprising:

  • (a) fluid pressure operable cylinder means operatively connected to a vehicle door for alternatively effecting opening and closing movements thereof, said cylinder means further comprising a pair of door-operating cylinders, each containing a pair of opposing chambers and a piston;

    (b) solenoid-operated door valve means for reversing the fluid pressure supplied to said cylinder means;

    (c) solenoid-operated supply valve means for alternatively effecting supply and release of fluid pressure to said door valve in response to respective first electrical signal or second electrical signal;

    (d) electronic means connected to said solenoid-operated supply valve means for transmitting such first electrical signal to said solenoid-operated supply valve means for effecting operation thereof to supply fluid pressure to said solenoid-operated door means in response to an operator input, and for transmitting such second electrical signal to said solenoid-operated supply valve in response to sensing a door obstruction during a door-opening operation, said electronic means further having a signal decoder, a door position flip-flop device connected with said signal decoder for storing the respective door position, a monitoring logic device connected to said signal decoder and said door position flip-flop device, a control logic device connected to said signal decoder and said door position flip-flop and said monitoring logic device, and a valve solenoid control device connected to said control logic device with output end stages for transmitting electrical energy to said solenoid-operated door valve to properly connect the direction of fluid pressure to effect door opening or closing, and said electronic means having an inlet connected to the push button and two inlets connected to the reversing switches;

    (e) a manually operable electric push button for manually effecting energization of said door valve;

    (f) a manually operable emergency valve device to provide manual venting of said cylinders;

    (g) a pair of reversing switches for evaluating the differential pressure in the cylinder chambers, thereby sensing obstructions on opening and closing;

    (h) a pair of limit switches for determining respective end positions of door closed and open positions; and

    (i) said electronic means having suppressing means for suppressing a reversing signal transmitted to inlets of said electronic means connected to reversing switches by a control logic device when an operator-initiated door command exists at such inlet connected to said electric push button.

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