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Anti-shoplifting system

  • US 4,800,369 A
  • Filed: 10/15/1986
  • Issued: 01/24/1989
  • Est. Priority Date: 10/21/1986
  • Status: Expired due to Fees
First Claim
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1. An anti-shoplifting system for identifying unauthorized removal of individual goods sold in shops by generating a theft-detection alarm and being capable of identifying the shoplifter, said system comprising:

  • a detector means mounted in the vicinity of each entrance and exit of the shop, said detector means having a signal-generating stage for generating a radiowave having a predetermined range, a signal-receiving stage for receiving a specific frequency, and a warning device for providing a warning signal upon receipt of said specific frequency;

    a signal generator unit, being attached to individual goods sold in the shop, for generating said specific frequency when said signal generator unit is within said predetermined range of said detector means, said signal generator unit includinga parallel wound coil, being a conductive wire wound at least once to form several interconnected coils to obtain a parallel array of coils, said parallel wound coil for receiving said generated radiowave from said signal-generating stage and for producing a magnetic field current;

    a switching circuit receiving said magnetic field current and for producing an "energized" signal;

    a flat miniature power pack receiving said "energized" signal and upon receipt of said "energized" signal being maintained in a switched-on condition for supplying power to said signal generator unit;

    an oscillation-modulation circuit for generating a radiowave of said specific frequency; and

    a signal-transmitting circuit for transmitting said generated radiowave from said oscillation-modulation circuit.

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