Hydraulic control system
US4676140A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 12, 1985 |
| Grant date | Jun 30, 1987 |
| Priority date | — |
| Expiry date | Sep 12, 2005 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B1/24
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A hydraulic control system for an elevator or other similar reciprocating user is disclosed, which comprises an adjustable throttle valve and a control or bypass valve disposed in the fluid supply line between the pump and elevator. A pressure difference balance is provided for controlling the operation of the control valve, and the pressure difference balance has one end operatively connected to the pressure provided by the pump, and the other end operatively connected to the pressure in the user or load line. The control valve is thus adapted to maintain a desired pressure difference across the throttle valve which is independent of the load on the user. In addition, the zero setting of the pressure difference balance is adjustable, so as to permit the system to be equally operable in both the upward and downward movements of the elevator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.