Fail safe locking mechanism for fluid operated valve actuator
US4248138A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 19, 1978 |
| Grant date | Feb 3, 1981 |
| Priority date | — |
| Expiry date | Sep 19, 1998 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B15/261
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A fail safe mechanism is provided for locking an actuating piston rod of a fluid operated actuator in a selected axial position in the event of a failure, or significant decrease in, the fluid pressure applied to the actuator. Preferably, a secondary cylinder is provided within the actuator cylinder and is in fluid communication therewith. A piston in the secondary cylinder is biased toward a locking position by a spring and is shiftable toward a released position by the existence of a predetermined amount of fluid pressure in the main cylinder. An annularly extending locking mechanism is provided in surrounding relationship to the actuating piston rod and is radially movable into engagement with a locking shoulder on such piston rod when the rod is shifted to one of its selected axial positions by the application of fluid pressure to the cylinder. In its locking position, the locking piston prevents any radial outward movement of the annularly extending locking means and thus mechanically locks the actuating piston rod in its selected axial position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.