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Tractor-trailer fluid pressure brake monitoring system

  • US 4,712,422 A
  • Filed: 08/19/1986
  • Issued: 12/15/1987
  • Est. Priority Date: 08/19/1986
  • Status: Expired due to Fees
First Claim
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1. In a tractor-trailer fluid pressure brake system in which a driver-operated first brake valve is operable to release fluid for applying the tractor and trailer brakes simultaneously, and a driver-operated second brake valve is operable independently of the first brake valve to release fluid for applying the trailer brakes selectively, an improved tractor-trailer brake monitoring system comprisingcircuit means including a monitoring switch responsive to operation of the second brake valve for producing a signal in accordance with operation thereof, anda timer circuit interconnected with said circuit means and responsive to said signal for registering the duration of selective trailer brake usage.

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