Hydraulic drive device for cargo handling vehicle
US9631613B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2014 |
| Grant date | Apr 25, 2017 |
| Priority date | — |
| Expiry date | Jun 12, 2035 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/88
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A hydraulic drive device for cargo handling vehicle has: a tank; a pump for drawing in a hydraulic oil from the tank and supplying the hydraulic oil to hydraulic cylinders; an electric motor for driving the pump; a solenoid-controlled proportional valve disposed between an inlet port of the pump and a bottom chamber of an up-and-down hydraulic cylinder and configured to open with a valve travel depending upon a control input of a descent control of an up-and-down control member; a pressure compensation valve disposed between a branch portion located between the pump and the solenoid-controlled proportional valve and the tank and configured to open with a valve travel depending upon a pressure difference between pressures upstream and downstream of the solenoid-controlled proportional valve; and a valve disposed between the pressure compensation valve and the tank and configured to be switched between an open position and a close position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.