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Intrusion alarm system

  • US 4,196,422 A
  • Filed: 01/03/1978
  • Issued: 04/01/1980
  • Est. Priority Date: 01/03/1978
  • Status: Expired due to Term
First Claim
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1. In an intrusion alarm system:

  • a closure having a latch assembly that includes a knob on one side of said closure for enabling opening of said closure as a result of operation of said assembly, said operation requiring physical action by a person with respect to said knob;

    a lock mechanism included within said knob and selectively operable to lock or unlock said latch assembly;

    an alarm apparatus associated with said latch assembly and disposed on the side of said door opposite said one side, said alarm apparatus including a battery, a generator powered by said battery and responsive to an input signal for developing a sound signal, and a transducer responsive to said sound signal for delivering an audible warning signal;

    means responsive to said physical action for delivering said input signal to said generator when said latch assembly is in a locked condition of said lock mechanism;

    and said responsive means being effectively disabled when said latch assembly is in an unlocked condition of said lock mechanism.

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