TOW VEHICLE TRAILER BRAKING SYSTEM

• US 3,790,807 A
• Filed: 12/22/1972
• Issued: 02/05/1974
• Est. Priority Date: 12/22/1972
• Status: Expired due to Term

• Current Assignee: Louis P. Rossigno
• Original Assignee: Louis P. Rossigno
• Inventors: Rossigno, Louis P.
• Primary Examiner(s): Reger, Duane A.
• Assistant Examiner(s): Butler, D. C.
• Application Number:
  US05/317,859
• Time in Patent Office: 410 Days
• Field of Search: 303/7,9,13,15,2-4,20 188/3,359,16P,151A,151R,152 91/459,369,376
• US Class Current: 303/7
• CPC Class Codes: B60T 13/58 Combined or convertible systems
• CPC Class Codes: B60T 13/581 both hydraulic and pneumatic
• CPC Class Codes: B60T 13/72 in vacuum systems or vacuum booster units

Abstract

A solenoid operated control valve for establishing an operational pressure differential in a servomotor located in a trailer to activate the wheel brakes of the trailer in response to an operational electrical signal derived from corresponding hydraulic actuation of the wheel brakes of a tow vehicle.

Claims

1. In a tow vehicle-trailer braking system having separately operated wheel brakes on the tow vehicle and the trailer, means responsive to the actuation of the wheel brakes of the tow vehicle for operating the wheel brakes of the trailer, said means comprising:

a first housing having first and second chambers therein separated by wall means, said second chamber being connected to a source of vacuum;

piston means attached to said wall means for pressurizing hydraulic fluid for operating said trailer brakes;

a second housing having a bore therein, said bore having a first inlet port connected to said source of vacuum, a second inlet port connected to the atmosphere, an outlet port connected to said first chamber;

control valve means located in said bore for regulating the communication of vacuum and air at atmospheric pressure from the first and second inlet ports to the first outlet port;

actuation means connected to said control valve means for supplying an operational input to selectively position said control valve means in response to a first operational signal; and

transducer means connected to said tow vehicle for converting the operation of the wheel brakes of the tow vehicle into said first operational signal to sequentially operate the wheel brakes of the trailer.

2. The tow vehicle-trailer braking system, as recited in claim 1, wherein said actuation means includes:

hand control means for developing a second operational signal independently of said first operational signal to position said control valve means and operate said trailer brakes in response to an operator input.

3. The tow vehicle-trailer braking system, as recited in claim 1, wherein said actuation means further includes:

switching means for comparing said first and second operational signals and transmitting the more demanding signal to operate said control valve means.

4. The tow vehicle-trailer braking system, as recited in claim 3, wherein said second housing further includes:

a reaction chamber having means therein connected to said control valve means for balancing said operational input to limit the flow of air at atmospheric pressure through the first output port to said first chamber.

5. The tow vehicle-trailer braking system, as recited in claim 4, wherein said control valve means includes:

first plunger means located in said bore having an annular face extending from a guide surface on one end and a second piston on the other end, said second piston extending into said reaction chamber, said reaction chamber being connected to receive a operational hydraulic fluid for the trailer brakes;

poppet means located in said bore between said first and second inlet ports for cooperating with said annular face on the first plunger means and an annular seat in said bore for preventing simultaneous communication of air at atmospheric pressure and vacuum through said outlet port; and

push rod means responsive to said actuation means for moving said plunger means away from said poppet means to interrupt the communication of vacuum from the first port to the first chamber and permit air at atmospheric pressure to freely flow through the outlet port into the first chamber and create a pressure differential across said wall means with the vacuum in the second chamber, said pressure differential moving said piston means to pressurize the operational fluid for the trailer brakes.

6. The tow vehicle-trailer braking system, as recited in claim 5, wherein said actuation means includes:

soleNoid means located in said bore and connected to said transducer means; and

second plunger means surrounded by said solenoid means and connected to said push rod for transmitting said operational input force to said first plunger means.

7. The tow vehicle-trailer braking system, as recited in claim 6, wherein said transducer means includes:

a third housing having a control chamber therein, said control chamber being connected to receive the operational hydraulic fluid for the wheel brakes of said tow vehicle; and

monitor means located in said control chamber for developing said first operational signal from the hydraulic fluid for the wheel brakes of said tow vehicle.

8. The tow vehicle-trailer braking system, as recited in claim 7, wherein said monitor means includes:

a bellows fixed on one end to the third housing and surrounding the opening through which the hydraulic fluid from the tow vehicle is received, and another end;

cap means located on said another end for closing the bellows, said cap means having a stem extending through an insulating bearing in said third housing;

resilient means located between said cap means and said third housing for opposing expansion of said bellows by said hydraulic fluid operating said wheel brakes of the tow vehicle;

variable resistor means located in said control chamber and connected to said switching means; and

contact means carried by said bellows and connected to said switching means for engaging said variable resistor means to modify said first operational signal in a direct relationship to the pressure of the hydraulic fluid communicated to the wheel brakes of the tow vehicle.

9. The tow vehicle-trailer braking system, as recited in claim 8, including:

sway control means carried by said trailer and connected to said switching means responsive to horizontal harmonic motion for developing a third operational signal for operating said solenoid means to create a pressure differential across said wall means and momentarily actuate said wheel brakes of the trailer brakes.

10. The tow vehicle-trailer braking system, as in claim 9, including:

display means connected to said switching means for providing a continuous visual indication to an operator in the tow vehicle during transmission of said first and second operational signal to said solenoid means and a sequentially interrupted signal upon said third operational signal being transmitted.

11. In a tow vehicle-trailer braking system having separately operated wheel brakes on the tow vehicle and the trailer, means responsive to the actuation of the wheel brakes of the tow vehicle for operating the wheel brakes of the trailer, said means comprising:

a first housing having first and second chambers therein separated by wall means, said second chamber being connected to a first source of pressure, said wall means being adapted to pressurize a fluid for operating said trailer brakes;

a second housing having a bore therein, said bore having a first inlet port connected to said source of pressure, a second inlet port connected to a second source of pressure, an outlet port connected to said first chamber;

control valve means located in said bore for regulating the communication of said first and second sources of pressure from the first and second inlet ports to the first outlet port;

actuation means connected to said control valve means for supplying an operational input to selectively position said control valve in response to a first operational signal; and

transducer means connected to said tow vehicle for converting the operation of the wheel brakes of the tow vehicle into said first operational signal to sequentially operate the wheel brakes of the trailer.

12. The tow vehicle-trailer braking system, as recited in claim 11, wherein said transducer means includes:

monitor means proportionally responsive to increases in actuation forces to said tow vehicle for developing a corresponding opeRational signal to operate said control valve means.