Proportioning relay valve disabled by failed front braking circuit
US5340212A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 24, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Mar 24, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T13/261
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A fluid pressure braking system for a tractor-trailer combination vehicle includes a proportioning relay valve which controls communication to the rear wheel brakes of the tractor. When the tractor pulls a trailer, the proportioning control within the relay valve is disabled, but when the vehicle is operated in the "bobtail" mode without pulling a trailer a proportioned brake application is effected in which the braking pressure communicated to the rear brake actuator is a predetermined percentage of that in the front wheel braking circuit. The proportioning mechanism is also disabled when the front axle braking circuit malfunctions, so that upon loss of pressure of the front axle system, the driver effects a non-proportioned rear brake application.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.