Safety elevator
US5340182A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 4, 1992 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Sep 4, 2012 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B19/07
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An elevator for supporting a string of pipe in a well rig is actuable between a closed condition for gripping of the pipe and an open condition, and includes a safety device for preventing opening of the elevator when a string of pipe is positioned in and supported by the elevator, to thus prevent accidental dropping of the string into a well. The elevator may be opened and closed by air pressure, with the safety device preferably including a sensing element positioned to respond to the presence of a well pipe in the elevator at a location to be supported thereby, and a valve actuable by the sensing element to control the delivery of pressure fluid to the elevator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.