Railway service and parking brake actuator
US5176227A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 1, 1991 |
| Grant date | Jan 5, 1993 |
| Priority date | — |
| Expiry date | Aug 1, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16D55/2245
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A brake actuator for a railway brake which provides both service and parking braking comprises a cylinder having an operating cavity. A piston assembly extends into the operating cavity and has a stepped bore including second and smaller third cavities. A first hydraulic supply admits pressurized hydraulic fluid into the operating cavity to extend the piston assembly to apply the service brake. A spring applies a retracting force on the piston smaller than the hydraulic force. A hollow parking brake piston carried in the second cavity extends to react against the cylinder and extend the piston assembly in response to the supply of pressurized fluid to the second cavity from a second hydraulic supply to apply the parking brake. A mechanical lock, comprising a one-way clutch utilizing ramps and rollers, locks the piston extended from the piston assembly cylinder to maintain the parking brake applied upon removal of the second hydraulic supply force. An unlocking member is responsive to the supply of pressurized fluid to the third cavity from a third hydraulic supply to disable the clutch and enable the spring to retract the parking brake piston and the piston assembly to release the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.