Margin valve
US4196588A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 1, 1978 |
| Grant date | Apr 8, 1980 |
| Priority date | — |
| Expiry date | May 1, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/8663
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A supply or demand margin valve for use in hydraulic systems having at least one load provided with hydraulic fluid under pressure by a main pump, a pilot pump and at least one control valve for the load. The margin valve includes a valve body having a bore with a spool reciprocally received within the bore. A first port in the body extends to the bore and is adapted to be connected to the pilot pump. A second port in the body extends to the bore and spaced in relation to the first port and is adapted to be connected to a component of a hydraulic system other than a pilot pump. A spring is disposed in the valve body for applying a biasing force to the spool to urge the spool in one direction and a third port is in fluid communication with the pressure responsive surface and is adapted to be connected to a main pump so as to apply a force to the spool to urge the spool in the same direction as the spring. A fourth port connects with a pressure responsive surface for applying a force to the spool in bucking relation to the spring and a feedback passage in connection with an additional pressure responsive surface is in fluid communication with the second port for applying an additiona…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.