Full-function valve for heavy duty semi-trailer brake systems
US5445440A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 15, 1994 |
| Grant date | Aug 29, 1995 |
| Priority date | — |
| Expiry date | Mar 15, 2014 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T15/22
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A unitary full-function valve is used to control the operation of a service brake system and a spring brake system. The valve includes a valve body that has multiple ports, including separate ports for providing fluid communication to a spring brake chamber, a service brake chamber, a fluid reservoir and an exhaust port. The valve body also has ports for receiving pressurized supply fluid and control fluid. The supply fluid inhibits the activation of the spring brakes so that the spring brakes are activated when no supply fluid is present. The control fluid is used to activate the service brakes on demand. A biased one-way pressure protection valve is disposed in the valve body to isolate fluid in the service brake system from fluid in the spring brake system when the pressure in the service brake system falls below a variable pressure level. A passageway within the valve body connects the fluid in the spring brake system with the biased pressure protection valve to increase the variable pressure level in proportion to the pressure level in the spring brake system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.