Closed center programmed valve system with load sense
US4401009A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 1, 1981 |
| Grant date | Aug 30, 1983 |
| Priority date | — |
| Expiry date | Jun 1, 2001 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16K31/406
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A closed center programmed valve system having a load sense fluid source for control of the raising and lowering of load means by a raise and a lower normally closed two stage valve assembly. Each of the second stages of the valve assemblies has a poppet with a parabolic contour which is dimensioned to provide substantially linear flow rate change for minimized shock when the respective valve is actuated to the valve closed state. The load sense for the load means is taken from the outlet of the raise second stage without the requirement of a separate actuated valve or land with a load sense signal being applied to the fluid source during the time the raise valve assembly is actuated to the valve open state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.