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Portable alarm device

  • US 5,093,650 A
  • Filed: 06/28/1990
  • Issued: 03/03/1992
  • Est. Priority Date: 08/17/1988
  • Status: Expired due to Fees
First Claim
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1. A portable alarm device for monitoring areas against burglary, comprising a housing having an input (3) for the reception and an output (10) for the delivery of alarm-triggering signals which are processed between the input and output, a power supply (17) disposed in the housing, and an alarm (11) disposed on the housing, the alarm circuit including a reception sensor (3) on the input side of the housing (2) to receive the incoming signals:

  • a variable preamplifier (4) connected to the reception sensor (3) for varying the volume of the alarm according to the size of the area being monitored;

    the preamplifier being connected to;

    a) at least one rejector circuit frequency filter (5) for controlling the accessible frequency range of the alarm-triggering signals;

    b) a microprocessor (6) connected to the rejector frequency filter (5) to receive and transmit the said signals;

    a signal converter (8) consisting of a flip-flop circuit connected to the power supply (17) for activating the power supply (17);

    c) a relay (9) connected to the alarm (11) by the output (10) for transmitting the signals to the output (10) in order to sound the alarm (11);

    d) a time switch in the form of a pushbutton switch (12) connected to the signal converter (8) in order to delay the time or readiness of the alarm device for operation;

    e) a closed circuit connecting the power supply (17) to the alarm (11) through the signal converter (8) for delivering a constant low-intensity current with intermittent interruption by the signal converter (8).

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