Hydraulic systems
US5584224A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 11, 1995 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Oct 11, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/755
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An hydraulic lift system has an actuator connected to an hydraulic circuit, having a pump, via a supply line. A balanced seated valve is connected between the supply line and a reservoir, the valve being controlled by a solenoid and an electric drive unit. The drive unit supplies a gradually increasing or decreasing voltage to the solenoid to open or close the valve gradually. The valve has a valve member that is displaceable along its length and has a valve head of frusto-conical shape. A passage along the valve member balances fluid pressure across the valve member. The solenoid has an armature with a pole face that can be displaced towards a fixed pole face to unseat the valve member. The pole faces have complementary frusto-conical surfaces and there is a non-magnetic washer between them.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.