Braking control system for a trailer

• US 4,856,850 A
• Filed: 06/03/1988
• Issued: 08/15/1989
• Est. Priority Date: 10/17/1986
• Status: Expired due to Term

• Current Assignee: D & N Micro Products, Inc.
• Original Assignee: EPCO Products, Inc.
• Inventors: Aichele, William H., Krauskopf, Dale H., Hopkins, James O. Jr.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/205,568
• Time in Patent Office: 438 Days
• Field of Search: 303/6.01, 303/7, 303/9.63, 303/20, 303/22.1, 303/22.4, 188/3 A, 188/156, 188/158
• US Class Current: 303/20
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components

Abstract

The trailer brake control system for use in a trailer which is adapted to be towed by a towing vehicle. The trailer includes an electrically operated braking mechanism and the towing vehicle includes a brake pedal, at least one brake light, and a brake switch operated by the brake pedal to energize the brake light. The control system includes a short circuit indicator circuit to provide a short circuit signal when a short circuit condition is detected in the trailer brake mechanism. A manual switch is also provided to manually actuate the trailer brake mechanism and to provide a manual brake actuation signal. A second circuit including a NOR gate provides a variable amplitude brake actuation signal in response to the concurrent closure of the brake switch, the absence of a manual brake actuation signal, and the absence of a short circuit signal. An indicator light is responsive to the brake actuation signal to provide a signal indicative of brake actuation. An oscillator circuit provides a stream of pulses and a voltage comparator is responsive to the stream of pulses and to the variable amplitude brake actuation signal to provide a stream of variable width drive pulses. The drive pulses drive an electronic switch to cyclically and repetitively actuate the trailer brake mechanism thereby applying braking force to the brakes of the trailer.

Claims

1. A trailer brake control system for use in a trailer which is adapted to be towed by a towing vehicle, said trailer including an electrically operated brake mechanism, said towing vehicle including a brake pedal, at least one brake light, and a brake switch operated by said brake pedal to energize said brake light, the control system comprising:

first means responsive to a short circuit condition in said trailer brake mechanism for providing a short circuit signal;

manual switch means for manually actuating said trailer brake mechanism and for providing a manual brake actuation signal;

second means coupled to said first means and said manual switch means for providing a variable amplitude brake actuation signal in response to the closure of said brake switch;

disabling means coupled to said first means, said manual switch means, and said second means, responsive to said short circuit signal for disabling said second means, said disabling means disabling said second means in response to the presence of said manual brake actuation signal independently of the presence or absence of said short circuit signal;

indicator means coupled to said second means responsive to said brake actuation signal or providing a perceptible brake actuation indication signal;

oscillator means for providing a stream of sawtooth pulses;

voltage comparator means coupled to said oscillator means responsive to said stream of pulses and said variable amplitude brake actuation signal for providing a stream of variable width drive pulses; and

switch means coupled to said voltage comparator means and said second means, responsive to said stream of variable width drive pulses to cyclically and repetitively actuate said trailer brake mechanism, thereby applying braking force to the brakes of said trailer.

2. The control system according to claim 1 wherein said first means is connected to said indicator means to provide a perceptible indication of an electrical short circuit condition in the trailer brake mechanism.

3. The control system according to claim 2 wherein said indicator means comprises a light and wherein said perceptible indication of a short circuit condition is the flashing of said light.

4. The control system according to claim 1 wherein said indicator means comprises an indicator light, and wherein the intensity of said indicator light varies in proportion to the applied brake actuation force.

5. The control system according to claim 1 wherein the amplitude of the brake actuation signal is gradually increased at a selected rate and including selective control means for selectively and dynamically adjusting said rate.

6. The control system according to claim 1 including selective compensation control means for selectively adjusting the amplitude of the brake actuation signal to compensate the braking force for the weight of said trailer.

7. The control system according to claim 1 wherein said disabling means comprises a NOR circuit responsive to a normal braking operation sensed by simultaneous indication of an absence of actuation of said manual brake actuator, an absence of a short circuit condition, and an indication of the operation of the brake pedal switch means, said NOR circuit for disabling said second means during periods when a normal braking operation is not sensed.

8. The control system according to claim 7 wherein said towing vehicle includes a reverse gear and backup lights associated therewith, in which:

said NOR circuit is responsive to an indication that said towing vehicle is in reverse gear for disabling said second means.