Hydraulic door operating system
US5921604A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | May 15, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60C29/06
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic system for opening and/or closing the rear lift gate of a vehicle uses a double or single acting gas charged hydraulic cylinder. If double acting, a second piston separates the head side of the cylinder into hydraulic and gas chambers. A unidirectional (for the single acting cylinder) or a bidirectional (for the double acting cylinder) drives a pump to operate the cylinder. A solenoid actuated on-off valve selectively communicates the ports of the cylinder with tank pressure. A gas charge accumulator may also be provided. In the double acting embodiment, a two way ball shuttle valve which is vented in the center provides alternating communication between the two cylinder ports.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.