System and method for remotely releasing a parking brake on a disabled vehicle

1. A method of releasing or applying a parking brake of a disabled vehicle having a service braking system and a spring applied parking brake system with a towing vehicle to facilitate towing comprising:

providing a source of hydraulic fluid at the towing vehicle;

supplying the source of hydraulic fluid to the spring applied parking brake system of the disabled vehicle and controlling the pressure of the hydraulic fluid to a specified level, whereby the supplied hydraulic pressure at the specified level releases the spring applied parking brake of the disabled vehicle, the controlling performed from the towing vehicle, and

monitoring at least the pressure of the hydraulic fluid supplied to the disabled vehicle during towing, wherein the pressure in the hydraulic fluid being applied to the spring applied parking brake is controlled at two or more elevated pressure levels and hydraulic fluid at one of the two or more elevated pressure levels is supplied to the spring applied parking brake system so that disabled vehicles with parking brakes systems using varying parking brake system elevated hydraulic pressures can be towed,

wherein supply of hydraulic fluid, controlled to the specified level, and applied to the spring applied parking brake of the towed vehicle from the towing vehicle is through single line and return of the hydraulic fluid from the towed vehicle to the towing vehicle is through the same single line.

2. The method of claim 1 , wherein the monitoring step includes displaying pressure of the hydraulic fluid provided to the disabled vehicle and triggering an alarm if the pressure deviates from a target range or value.

3. The method of claim 1 , wherein the providing step further comprises providing a source of accumulated hydraulic fluid for release of the parking brake.

4. The method of claim 1 , wherein a pressure level of the hydraulic fluid provided by the towing vehicle is monitored.

5. The method of claim 1 , wherein the controlling step further comprises providing the hydraulic fluid at a controlled pressure and then reducing the pressure of the hydraulic fluid for use by the parking brake system of the disabled vehicle.

6. The method of claim 5 , wherein the controlled pressure and reduced pressure are monitored.

7. The method of claim 1 , wherein the supply of the hydraulic fluid is terminated so as to apply the parking brake of the disabled vehicle.

8. The method of claim 1 , wherein the source of hydraulic fluid is provided on a towing vehicle having a gooseneck hitch for towing.

9. A system for releasing a spring applied parking brake of a disabled vehicle with a towing vehicle to facilitate towing comprising:

a source of hydraulic fluid, the source of hydraulic fluid being provided in at least two different elevated pressure levels at the towing vehicle;

means for selecting one of the at least two different elevated pressure level hydraulic fluids and supplying the selected hydraulic fluid to the spring applied parking brake system of the disabled vehicle;

means for controlling and monitoring the supply of the hydraulic fluid to the disabled vehicle, the controlling and monitoring means located on the towing vehicle so as to control the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle, wherein the ability of supplying the different elevated pressure level hydraulic fluids to the disabled vehicle permitting towing of disabled vehicles with parking brakes systems using varying parking brake system hydraulic pressures,

wherein a single line between the towing vehicle and the towed vehicle is used for both supply and return of the selected hydraulic fluid applied to the spring applied parking brake system.

10. The system of claim 9 , wherein the means for supplying the source of hydraulic fluid is one or more hoses on the towing vehicle, the hose adapted to connect to the spring applied parking brake system of the disabled vehicle for supply of the hydraulic fluid to the spring applied parking brake system.

11. The system of claim 9 , wherein the controlling and monitoring means includes an accumulator, the accumulator in communication with the source of hydraulic fluid and providing the supply of hydraulic fluid to the disabled vehicle that is controlled and monitored for towing of the disabled vehicle.

12. A system for releasing a parking brake of a disabled vehicle with a towing vehicle to facilitate towing comprising:

a source of hydraulic fluid provided at the towing vehicle;

means for supplying the hydraulic fluid via an output line to a parking brake system of the disabled vehicle;

means for controlling and monitoring the supply of the hydraulic fluid to the disabled vehicle, the controlling and monitoring means located on the towing vehicle, wherein the means for controlling and monitoring further comprises:

a) a control valve located on the towing vehicle, the control valve adapted to supply hydraulic fluid via the output line based on a sensed pressure;

b) an accumulator adapted to receive supplied hydraulic fluid from the output line of the control valve for supply to the disabled vehicle via an output line;

c) a pressure switch sensing pressure in the output line to control the output of the control valve;

d) a solenoid valve adapted to control flow of hydraulic fluid from the output line of the control valve to the supplying means using a return line to a hydraulic fluid tank on the towing vehicle;

e) a pressure transducer for monitoring the pressure in the output line and pressure of hydraulic fluid to the supplying means; and

f) a display located in the towing vehicle and adapted to display the monitored pressures from the pressure transducers,

wherein a single line between the towing vehicle and the towed vehicle is used for both supply and return for the hydraulic fluid applied to the spring applied parking brake system.

13. The system of claim 12 , comprising at least one pressure reducer in communication with an output of the accumulator, an output line of the pressure reducer in communication with the supplying means.

14. The system of claim 12 , comprising a plurality of pressure reducers, each having a respective pressure transducer, the plurality of pressure reducers adapted to provide the hydraulic fluid at different pressure levels to accommodate different types of parking brake systems.

15. The system of claim 12 , comprising an alarm associated with each pressure transducer, the alarm adapted to signal an operator of the towing vehicle when pressure of hydraulic fluid supplied by the towing vehicle or hydraulic fluid supplied to the disabled vehicle varies from a target range or value.

16. The system of claim 14 , comprising an alarm associated with each pressure transducer, the alarm adapted to signal an operator of the towing vehicle when pressure of hydraulic fluid supplied by the towing vehicle or hydraulic fluid supplied to the disabled vehicle varies from a target range or value.

17. In a towing vehicle having a hitch for towing of a disabled vehicle, the improvement comprising the towing vehicle including the system of claim 9 for controlling the parking brakes on the disabled vehicle.

18. The towing vehicle of claim 17 , wherein the towing vehicle has a gooseneck hitch.

19. The towing vehicle of claim 18 , wherein the gooseneck hitch includes a grab hook for latching to a low boy trailer.