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Automatic door safety system

  • US 4,866,881 A
  • Filed: 05/31/1988
  • Issued: 09/19/1989
  • Est. Priority Date: 05/31/1988
  • Status: Expired due to Fees
First Claim
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1. An automatic sliding door structure comprising a door adapted to be mounted for movement in the doorway of a support structure, a plurality of presence sensing beam producing transducers arranged to produce presence sensing beams in overlapping relation to one another, spanning the path of movement of the door and extending at least a predetermined distance on each side of the doorway, power means for actuating the door, means actuated upon movement of the door in both directions of movement for switching the transducers on sequentially in the door opening mode and for switching the transducers off sequentially in the door closing mode and means providing a predetermined pulsing of the transducers and the beams produced thereby.

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