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Merchandise theft deterrent sensor

  • US 4,772,878 A
  • Filed: 05/06/1987
  • Issued: 09/20/1988
  • Est. Priority Date: 05/06/1987
  • Status: Expired due to Fees
First Claim
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1. A theft detection system, comprising:

  • a. an alarm means;

    b. a deformable membrane switch sensor, including;

    i. a first membrane providing conducting networks on both sides thereof;

    ii. a second membrane disposed adjacent the first membrane and providing an electrical shielding network therefor;

    iii. a third membrane disposed between and insulating the first and second membranes;

    iv. electrical leads connecting the conducting networks and the shielding network with the alarm means;

    the membranes being adapted on deformation to effect contact between the conducting networks to produce a signal from the sensor to the alarm means;

    c. a moveable piston assembly in close proximity to the membrane switch, and radially spaced from the electrical networks, the piston being adhesively secured to an article of merchandise, and;

    i. on an initial slight movement, to temporarily deform the membrane switch and produce a test signal from the sensor when the alarm means is in a test mode;

    ii. upon termination of the initial movement, to rebound to its initial state and terminate the test signal; and

    iii. to deform the membrane switch and produce a theft alarm when actuated by a theft movement when the alarm means is active;

    d. container means for the membrane switch sensor and the moveable piston, the container being adhesively secured to an article of merchandise, a cavity being defined within the container means, of the cavity, and the piston at one end thereof is in close proximity to an opposing surface of the cavity;

    whereby, separation of the merchandise from the container means will move the piston, deform the membranes and produce a theft alarm, and following removal of the container from the merchandise, the sensor, including the piston and membrane switch will rebound to the original electrical state of the sensor.

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