TRAILER BRAKE CONTROL SYSTEM

• US 3,780,832 A
• Filed: 07/03/1972
• Issued: 12/25/1973
• Est. Priority Date: 07/03/1972
• Status: Expired due to Term

• Current Assignee: John J Marshall
• Original Assignee: John J Marshall
• Inventors: Marshall, John J.
• Primary Examiner(s): Reger, Duane A.
• Application Number:
  US05/268,748
• Time in Patent Office: 540 Days
• Field of Search: 188/3R,112 303/7,20
• US Class Current: 188/3.00R
• CPC Class Codes: B60T 13/58 Combined or convertible systems

Abstract

A trailer brake control system for use with the hydraulic brake system of an automobile having a brake light and a switch therefor responsive to fluid pressure, in which an adjustable time base circuit is connected to the light switch and produces a signal which is amplified by an amplifier circuit connecting the automobile electrical power supply with a line to the electric brake mechanism in the trailer. A variable resistor controls the time base circuit and is initially adjusted for the type of brakes and loads for synchronizing the operation of the brakes on the towed and towing vehicles for delaying the operation of the trailer brakes until the slower acting hydraulic brakes of the automobile have been applied. An emergency circuit controlled by a switch within easy reach of the driver of the automobile, bypasses both the time base and amplifier circuits to control directly the trailer brakes.

Claims

1. A trailer brake control system for use with an automobile hydraulic brake system having a brake light and a switch therefor responsive to foot pedal movement:

comprising a variable time delay circuit having a variable control means therein including a capacitor and a variable resistor to obtain the desired delay in the operation of the brake mechanism in the trailer relative to the operation of the brake system of the automobile, a lead connecting said circuit to the switch controlling an electrical input line for connection with the brake light, and an amplifier circuit controlled by the automobile electrical power supply through said time delay cricuit and connecting said input line to the trailer brake operating circuit.

2. A trailer brake control system as defined in claim 1, in which an emergency circuit connects said input line to the trailer brake operating circuit and bypasses said first two circuits.

3. A trailer brake control system as defined in claim 2 in which said emergency circuit includes a manually operated switch for location within easyreach of the driver of the automobile.

4. A trailer brake control system as defined in claim 1 in which a lead having a variable resistor therein is connected to said amplifier circuit.

5. A trailer brake contRol system as defined in claim 2 in which a lead having a variable resistor therein is connected to said amplifier circuit.

6. A trailer brake control system as defined in claim 1 in which said amplifier circuit includes a series of transistors responsive to the signal from the time base circuit.

7. A trailer brake control system as defined in claim 5 in which said amplifier circuit includes a series of transistors responsive to the signal from the time base circuit.

8. A trailer brake control system as defined in claim 1 in which a transistor and resistor prevent the operation of the capacitor until a signal is received from the brake light switch in response to the application of the hydraulic brakes of the automobile.

9. A trailer brake control system as defined in claim 7 in which a transistor and resistor prevent the operation of the capacitor until a signal is received from the brake light switch in response to the application of hydraulic brakes of the automobile.