Parking brake valve for a hydraulic external force brake system
US4652059A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 24, 1985 |
| Grant date | Mar 24, 1987 |
| Priority date | — |
| Expiry date | Sep 24, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T15/02
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A parking brake valve cooperates with a spring loaded cylinder which releases a parking brake when pressurized. The valve includes a shaft with an eccentric section, and this shaft may be turned by an actuating lever from a position in which the brake is engaged to a released position. In the released position, the eccentric section of the shaft causes the movement of a control piston, permitting the spring loaded cylinder to be pressurized, releasing the brake. The pressure applied to the spring loaded cylinder is also provided to a radial surface on the shaft, causing the shaft to be friction locked in the released position, despite a spring force applied by a control spring tending to return it to the braking position. If a breakdown occurs in the parking brake system, however, the pressure to the spring loaded cylinder will drop, releasing the friction lock. The control spring then returns the shaft to the braking position, automatically bringing the actuating lever into its braking position, indicating that the parking brake is applied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.