Warning circuit for a tractor/trailer combination

• US 4,065,751 A
• Filed: 10/18/1976
• Issued: 12/27/1977
• Est. Priority Date: 10/18/1976
• Status: Expired due to Term

• Current Assignee: General Motors Corporation (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Stewart, John A., Hynes, Roy G., Beyerlein, David G., Force, John B.
• Primary Examiner(s): Waring, Alvin H.
• Application Number:
  US05/733,347
• Time in Patent Office: 435 Days
• Field of Search: 340/52 F, 340/52 R, 340/53, 340/58, 180/103, 307/10 R
• US Class Current: 340/442
• CPC Class Codes: B60C 23/0425 Means comprising permanent magnets, e.g. Hall-effect or Reed-switches

Abstract

A circuit is provided for a tractor/trailer combination to provide a warning in the tractor of an event such as low tire pressure occurring at the trailer utilizing only conventional wiring connections between the tractor and trailer. When low tire pressure occurs, a flasher circuit on the trailer flashes the trailer marker lamps which are normally energized so that the flashing lamps are visible to the operator. The electrical pulses in the marker lamp circuits are sensed by a detector in the tractor to illuminate an indicator lamp in the tractor.

Claims

1. In a tractor/trailer electrical circuit having an electrical power supply carried by the tractor and signal lamps carried by the traler, a warning circuit for indicating in the tractor an event occurring in the trailer comprising

a conductive path for supplying electrical power from the power supply to energize the signal lamps,

means for sensing an event occurring in the trailer and providing a corresponding event signal,

means responsive to the event signal and connected to the said conductive path for repetitively opening and closing the conductive path at a low rate allowing the signal lamps to substantially cool when the path is opened and the lamps are de-energized, whereby each time the lamps are energized a large current pulse is produced in the conductive path, and

means in the tractor for indicating the said event occurring in the trailer including an indicating lamp, a circuit for detecting the said large current pulses in the conductive path and means responsive to the said large pulses for energizing the indicating lamp.

2. In a tractor/traler electrical circuit having an electrical power supply carried by the tractor and marker lamps carried by the trailer and a universal electrical interconnection coupling the tractor and trailer, a warning circuit for indicating in the tractor an event occurring in the trailer comprising

a conductive path passing through the electrical interconnection for supplying electrical power from the power supply to energize the signal lamps,

means for sensing an event occurring in the trailer and providing a corresponding event signal,

an electrical trailer flasher circuit connected to and energized by the said conductive path including multivibrator means responsive to the event signal and connected to the said conductive path for repetitively opening and closing the conductive path to the marker lamps to provide a first flashing visual signal to the tractor operator, the flashing being limited to a low rate allowing the marker lamps to substantially cool when the path is opened and the lamps are de-energized, whereby each time the lamps are energized a large current pulse is produced in the conductive path, and

means in the tractor for indicating the said event occurring in the trailer including an indicating lamp, a circuit for detecting the said large current pulses in the conductive path and means responsive to the said large pulses for energizing the indicating lamp to provide a second visual signal to the tractor operator.

3. In a tractor/trailer electrical circuit having an electrical power supply carried by the tractor and signal lamps carried by the trailer, a warning circuit for indicating in the tractor an event occurring in the trailer comprising

a conductive path for supplying electrical power from the power supply to energize the signal lamps,

means for sensing an event occurring in the trailer and providing a corresponding event signal,

means responsive to the event signal and connected to the said conductive path for repetitively opening and closing the conductive path at a low rate allowing the signal lamps to substantially cool when the path is opened and the lamps are de-energized, whereby each time the lamps are energized a large current pulse is produced in the conductive path, and

means in the tractor for indicating the said event occurring in the trailer including an indicating lamp, a circuit for detecting the said large current pulses in the conductive path comprising a step-up transformer having a primary winding energized by the said large current pulses and a secondary winding for producing corresponding high voltage pulses, a detector circuit connected to the secondary winding and responsive to each of high voltage pulses for generating a trigger signal, and a one-shot multivibrator responsive to each such trigger signal for energizing the indicator lamp for a preset period such that the indicator lamp is energized each time the signal lamps are energized.