Hydraulic door operator
US4296570A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 7, 1979 |
| Grant date | Oct 27, 1981 |
| Priority date | — |
| Expiry date | Sep 7, 1999 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/20561
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An automatic door operator for opening and closing a door such as a cold storage door which is mounted in a frame for sliding movement in a vertical plane has a hydraulic control system which includes an electric motor for rotating a reversible hydraulic pump, an electric control circuit which activates the electric motor to rotate the pump in the appropriate direction, and a reversible rotary hydraulic motor driven by the pump to rotate a chain drive which draws the door to its open and closed positions. The hydraulic control system also includes a means for cushioning the rapid start and stop of the door to provide smooth operation which includes a pair of check valves disposed in the control system such that one check valve is on either side of the hydraulic pump, and a first set of pressure relief valves disposed in the control system on either side of the pump between the pump and the check valves, and a second set of pressure relief valves between the check valves and the hydraulic motor. The check valves provide a locking mechanism for the door so that when the flow of hydraulic fluid from the pump stops, the door is locked in its open or closed position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.