Elevator valve apparatus
US5040639A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Jan 31, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B1/24
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
An elevator valve apparatus for controlling the hydraulic supply flow to the hydraulic actuator and the hydraulic discharge flow from the actuator, comprises a solenoid proportional control valve device for ascending, a solenoid proportional control valve device for descending, and a valve control unit for controlling both of the control valve devices with a predetermined acceleration characteristic and a predetermined deceleration characteristic by an open loop control system. Furthermore, if preferable, the valve control unit carries out oil temperature compensating control, pressure compensating control, pre-start pressure raising compensation control, and feedback control of the supply flow in the low speed ascending.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.