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Alarm system

  • US 4,124,840 A
  • Filed: 05/24/1976
  • Issued: 11/07/1978
  • Est. Priority Date: 01/30/1976
  • Status: Expired due to Term
First Claim
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1. An alarm system comprising(a) detection means including a drive unit movable with a variation in the magnitude of a physical quantity, a plurality of detection channels each having a predetermined threshold value different from the others, each channel comprising a movable conductor operatively connected with the drive unit for movement thereby and electrically connected with the ground, a pair of stationary conductors adapted to have a control voltage applied thereto and being engageable by said movable conductor during movement of the latter, and a flipflop circuit having a pair of input terminals connected with the respective stationary conductors, said movable conductor in each channel upon being moved by said drive unit from engagement with one of the stationary conductors into engagement with the other of said pair of stationary conductors causing said flipflop circuit to produce a binary signal representative of the magnitude of the physical quanity;

  • (b) selection means for selecting a predetermined one of the threshold values in form of a binary signal and comprising a plurality of selection channels each associated with a detection channel of said detection means, means for applying a control voltage to each of the selection channels, and grounded switch means operatively connected with each of the selection channels for connecting a selected number thereof to ground providing thereby a binary signal representative of a selected threshold value;

    (c) comparison means for comparing, as input signals thereto, an output signal of the detection means with an output signal from the selection means and producing an electrical output signal when the magnitude of the physical quantity exceeds the threshold value selected by the selection means; and

    (d) a utilization device supplied with the electrical output signal from the comparison means to provide an alarm when the magnitude of the physical quantity exceeds the threshold value selected by the selection means.

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