Hydraulic control system
US5351601A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1992 |
| Grant date | Oct 4, 1994 |
| Priority date | — |
| Expiry date | May 4, 2012 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/8609
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic control system in which the flow of hydraulic fluid to and from cylinders on either side of a piston is controlled by normally closed check valves that are opened whenever a control valve is not in its neutral state. Float check valves respectively in series with the check valves and the check valves are opened when the control valve is in a neutral state by pressure from one of the cylinders so as to permit the load to move freely in response to external forces applied to it. A normally closed check valve is provided in which load sense pressures drive it open and pressure from a cylinder is balanced out. A cross check valve is such that the ratio of the areas for driving it open to the area for keeping it shut are at least 35:1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.