Proportioning brake control valve with caged tare pressure spring
US4850651A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 6, 1988 |
| Grant date | Jul 25, 1989 |
| Priority date | — |
| Expiry date | Sep 6, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T15/18
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A proportioning control valve for heavy duty fluid pressure braking system includes a proportioning piston which is normally held in engagement with an abutment by control pressure. A tare pressure spring urges a caging member into engagement with a stop which is spaced a predetermined distance from the end of the proportioning piston, which is less than the distance between the valve engaging member carried by the proportioning piston in the proportioning valve member. Upon loss of pressure at the control pressure port, the proportioning piston is urged toward the caging member. The proportioning piston moves between the gap defined between the end of the proportioning piston and the caging member without opposition from the tare pressure spring, thereby permitting the full force of fluid pressure to break seal friction between the seals carried by the proportioning piston and the wall of the housing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.