Impact drilling tool
US4044844A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1976 |
| Grant date | Aug 30, 1977 |
| Priority date | — |
| Expiry date | Jul 19, 1996 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B4/14
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A fluid operated impact drilling tool has a hammer slidably mounted in a casing connected to a string of drilling pipe. Inside the casing above the hammer is mounted a valve. Both the valve and hammer have reciprocal sliding movement along the longitudinal axis of the tool to substantially interrupt flow of a drilling fluid therethrough. Movement of the valve and hammer predominantly results from different pressures acting on separate pressure areas of the valve and hammer. The hammer may impact either an anvil or a bit attached thereto. Wear on the valve and hammer is reduced by smooth, hardened surfaces at locations subject to wear. A trapped fluid may also be used in an alternative embodiment to dampen the shock effect of the valve as it reaches its upper and lower stops.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.