BRAKE CONTROL SYSTEM FOR A TRACTOR DRAWN TRAILER

• US 3,574,414 A
• Filed: 10/16/1968
• Issued: 04/13/1971
• Est. Priority Date: 10/16/1968
• Status: Expired due to Term

• Current Assignee: Jacob, Keith D.
• Original Assignee: Jacob, Keith D.
• Inventors: Jacob, Keith D.
• Application Number:
  US04/768,062
• Time in Patent Office: 909 Days
• US Class Current: 303/7
• CPC Class Codes: B60T 13/74 with electrical assistance or drive

Abstract

The electric brakes of a tractor drawn trailer are controlled by a force sensor so positioned that pressure applied by the foot of the driver during actuation of the tractor brake pedal also operates the sensor. The electrical system thus activated is independent of the tractor braking system. Solid state devices are used in preference to switches or contractors, and included are effective means for voltage control. Such arrangement provides adjustable braking force proportional to the tractor braking force, relative braking adjustment, variable maximum braking, and automatic operation after adjustment.

Claims

1. In a control system for trailer wheel brakes of a tractortrailer assembly:

a first brake power source connection on the tractor;

a brake pedal on the tractor actuable to apply said tractor brakes thru said first power source connection;

a second brake power source connection independent of said first power source connection for applying said trailer wheel brakes;

a multicomponent electrical control circuit intermediately connected between said second power source and said trailer brakes;

a variable resistance component of said multicomponent circuit mounted on said brake pedal responsive to variations in pressure applied to said variable resistance component connected to vary voltage output thru said circuit and thereby to regulate actuation of said trailer brakes; and

means responsive directly to the mechanical force applied to actuate said brake pedal to also actuate said variable resistance component.

2. The control system of claim 1 wherein said variable resistance component comprises:

a variable resistance material whose resistance is a function of pressure thereon;

a pair of conductive plates with said variable resistance material positioned therebetween;

a pair of conductive wires attached one to each of said plates for connection to said electrical control circuit; and

means to mount said pairs of plates with said variable resistance therebetween in position to receive the mechanical force to thereby vary resistance from one plate to the other through said variable resistance material.

3. The control system of claim 1 wherein a manually adjustable resistance in said control circuit limits the maximum voltage and current for actuating said trailer brakes.

4. The control system of claim 3 in which said circuit includes a transistor, and a diode and a potentiometer control the voltage at the base of said transistor to determine the maximum average voltage applied to the trailer wheel brakes.

5. The control system of claim 4 wherein another manually adjustable resistance controls the braking of the trailer relative to the braking of the tractor.

6. The control system of claim 1 wherein means are provided to vary voltage thru said circuit independent of said variable resistance component.

7. The control system of claim 6 wherein a major portion of the components of said control circuits is mounted adjacent the driver, including the said means to vary voltage thru the circuit independent of said variable resistance component.

8. In a tractor vehicle having a brake pedal, a multicomponent electrical circuit having means to vary and control voltage and current output therethrough:

a variable resistance material whose resistance is a function of pressure thereon;

a pair of conductive plates with said variable resistance material positioned therebetween;

a pair of conductive wires attached one to each of said plates for connection to said electrical circuit;

means to mount said pairs of plates with said variable resistance therebetween in position on the brake pedal for actuation by direct mechanical pressure exerted by the driver of the tractor vehicle to vary the resistance from one plate to the other through variable resistance material and thereby to actuate the tractor brakes;

an adjacent transistor in said circuit, the lowest voltage limit at the base of which determines the maximum average voltage at the output of said circuit; and

a diode and potentiometer adjustable to control the voltage at the Base of said adjacent transistor whereby maximum voltage at the output of said circuit may be preset.