Closed center programmed valve system with load sense
US4276811A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1979 |
| Grant date | Jul 7, 1981 |
| Priority date | — |
| Expiry date | Apr 30, 1999 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B13/02
- WIPO fieldOther special machines
- 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 control 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.