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Traffic responsive control system

  • US 4,669,218 A
  • Filed: 06/13/1986
  • Issued: 06/02/1987
  • Est. Priority Date: 03/08/1984
  • Status: Expired due to Term
First Claim
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1. In an automatic door installation having a swinging door, a power operator for swinging the door between a closed position thereof closing a doorway opening and an open position thereof on a swing side of the doorway opening, and a traffic responsive control system comprising radiant energy emitter and receiver means for sensing doorway traffic along a traffic path of travel through the doorway opening, and door control means operated by the traffic sensing means to automatically open the door for traffic to pass along said traffic path of travel, the improvement wherein the traffic sensing means comprises at least one multiple emitter sensor having a bank of a plurality of radiant energy emitters for emitting respective radiant energy beams with axes spaced along the said traffic path of travel and collectively providing an effective emitted radiant energy coverage area intersecting said traffic path of travel and radiant energy receiver means for receiving reflected radiant energy emitted from the bank of emitters thereby to sense traffic in said effective coverage area, said one multiple emitter sensor being mounted adjacent one side of the doorway opening and providing a said effective coverage area on one side of the door, and wherein the traffic responsive control system further comprises emitter selector means for individually selecting the emitters of each said sensor in time spaced sequence for emission of radiant energy, the emitter selector means comprising power level selector means for individually establishing, at each of a plurality of angular positions of the door as the door is swung between its said closed and open positions, the radiant energy emission level of each emitter, when selected, for establishing said effective coverage area of the sensor at each said angular position of the door.

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