Valve unit
US4716933A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 16, 1986 |
| Grant date | Jan 5, 1988 |
| Priority date | — |
| Expiry date | Oct 16, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87241
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A valve unit for use in a load sensing system having a fluid operated cylinder. The valve unit permits positioning of an implement between the raise, lower, neutral and float positions and also provides for throttling of fluid flow to the cylinders as well as priority flow to the system. Float is obtained through a lock check valve which includes a main poppet maintained in a seated position by a spring biased pilot poppet. A pilot piston is positioned coaxially opposite the main poppet and is responsive to fluid pressure in the valve to act upon the pilot poppet and unseat the main poppet. In the float position, the fluid pressure within the valve may be stand-by pressure which acts upon the pilot piston to allow it gradual decent of the implement. The pilot pressure is communicated to the pilot piston through a centrally located passage. The location of the passage permits additional lock check valves to be easily added as needed. An adjustable priority flow control valve is included in the valve body for manual adjustment of the priority in the system and the flow rate of fluid.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.