Compressed air percussive mechanism for a down hole hammer and down hole hammer
US7757779B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2002 |
| Grant date | Jul 20, 2010 |
| Priority date | — |
| Expiry date | Jun 5, 2024 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B4/14
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
Pressure-air driven percussion device for a down-the-hole drill with a hammer-piston which is axially reciprocally movable in a hammer-piston chamber through a driving device. The hammer-piston in operation acting with a hammer-end against an upper end of a drill bit which is positioned inside a chuck. An air-cushion for reducing percussive power is arranged to be formed at the hammer-end of the hammer-piston in positions where the drill bit has been moved past a predetermined distance in the percussion direction. The drill bit is sealingly slidingly supported in a drill bit bushing, and the hammer-end of the hammer-piston is formed so that it sealingly cooperates with the drill bit bushing in the positions in order to form the air-cushion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.