Programmed unbalanced load valve system
US4202250A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 1976 |
| Grant date | May 13, 1980 |
| Priority date | — |
| Expiry date | Sep 13, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87177
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A valve system for an unbalanced load having a first two stage valve assembly operable for raising the load and a second two stage valve assembly for lowering the load. Each of the second stages has a poppet with a parabolic contour which is dimensioned with orifice parameters to provide substantially linear flow rate change when the second stage poppet moves for substantially zero flow jerk. In addition, the raise valve assembly has a pilot line coupled directly to the load so that high pressure oil is instantly available to actuate the second stage poppet. The lower valve assembly has a dashpot to decrease the rate of opening of that second stage poppet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.