Device for retrieving objects from wells
US4545432A · kind A · utility
Inventor
Key dates
| Filing date | Apr 9, 1985 |
| Grant date | Oct 8, 1985 |
| Priority date | — |
| Expiry date | Apr 9, 2005 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B31/16
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A wash-over type down hole retrieving device or fishing tool is described, consisting of a hollow cylindrical body having an open lower end. The body has concentric inner and outer walls, defining an annular space in which an annular piston can force down an annular sleeve of a malleable alloy having downwardly extending finger-like formations. The inside of the lower end of the outer wall is of cupped configuration effective to deflect the fingers inwards and over the open end of the body so as to trap and retain an object for retrieval. The annular piston is forced down hydraulically by dropping a diverter ball valve. Cutting teeth are optionally provided on the outer periphery of the lower end of the outer wall, on a detachable shoe.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.