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Dual sensor electromagnetic door lock system

  • US 4,893,852 A
  • Filed: 01/17/1989
  • Issued: 01/16/1990
  • Est. Priority Date: 01/17/1989
  • Status: Expired due to Fees
First Claim
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1. An electromagnetic lock system adaptable for providing controlled access through a doorway having a frame mounting a door with an armature comprising:

  • housing means mountable to the door frame;

    electromagnetic lock means mounted to said housing means and selectively electrically energizeable for magnetically bonding with the armature to provide a locked state;

    ultrasonic sensor means mounted in said housing means for generating an ultrasonic detection beam traversing a path remote from said housing and for receiving reflected echoes from said beam;

    passive infrared sensor means mounted in said housing means for sensing radiant energy temperature changes from a detection zone remote from said housing means;

    processing means mounted in said housing means for processing said received reflected echoes to detect the presence of a foreign object in said beam and for processing said sensed radiant energy to detect the movement of a foreign object into the detection zone; and

    lock release means responsive to said processing means for automatically transforming said electromagnetic lock means to a non-locked state for a pre-established time interval upon detection of a foreign object in said beam and movement of the object into said detection zone.

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