Pressure control for a pair of parallel hydraulic circuits
US5826487A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 20, 1997 |
| Grant date | Oct 27, 1998 |
| Priority date | — |
| Expiry date | Feb 20, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/781
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An unloader valve is connected to a pump and has first and second ends, a priority flow port communicating with the first end and being connected to a first conduit connected to a first hydraulic circuit, an excess flow port communicating with a tank, and a spring disposed at the second end biasing the unloader valve to a priority flow position with a force sufficient to maintain the pressure in the priority flow port above a predetermined minimum level. The unloader valve is biased toward an unloading position in opposition to the spring force by pressure generated force acting on the second end. A check valve is disposed between the first conduit and a second conduit connected to a second hydraulic circuit. A valve device controls the pressure at the second end of the unloader valve in response to pressure in the second conduit so that pressure in the second conduit is maintained above a second higher predetermined level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.