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Alarm system for preventing an automotive vehicle driver from dozing at the wheel

  • US 4,509,040 A
  • Filed: 12/01/1981
  • Issued: 04/02/1985
  • Est. Priority Date: 12/01/1981
  • Status: Expired due to Term
First Claim
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1. An alarm system for preventing an automotive vehicle driver from dozing while driving, comprising:

  • a steering angle detector for detecting angular displacement of a steering member from a neutral position and producing a first signal having a value which is proportional to the detected displacement;

    a discriminator for detecting a condition wherein said first signal value exceeds a threshold value and detecting a rate of variation of the steering angular displacement higher than a predetermined value, which discriminator produces a discriminator signal when said first signal value exceeds said threshold value and said rate of variation is higher than said predetermined value;

    a counter for counting occurrences of said discriminator signal and producing an alarm signal when the counted value reaches a preset value;

    a counter enabling signal generator associated with said counter and producing a counter enabling signal while a preselected steady cruise condition is satisfied, which enabling signal makes said counter operative to count said occurrences of said discriminator signal while said enabling signal is present and otherwise disables the counter operation and clears the counter value; and

    an alarm device responsive to said alarm signal to produce an alarm for preventing the driver from dozing at the wheel.

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