Hydraulic control valve
US4714296A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 19, 1985 |
| Grant date | Dec 22, 1987 |
| Priority date | — |
| Expiry date | Nov 19, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60T2270/203
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A hydraulic control valve may have a first chamber having an input port, to which an input hydraulic pressure is applied and an output port, and a second chamber having a third port to which a hydraulic control pressure is applied. When a hydraulic pressure below a predetermined level is applied to the first port, the same hydraulic pressure is produced at the second port. When a hydraulic pressure above the predetermined level is applied to the first port, the hydraulic pressure is reduced at a fixed ratio, and thereby a hydraulic pressure lower than the hydraulic pressure applied to the first port is produced at the second port. Thus the hydraulic control valve functions as a proportional valve. When a hydraulic control pressure is applied to the third port, the first and second port are disconnected. Thus the hydraulic control valve functions as a cutoff valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.