Annular air-hammer apparatus for drilling holes
US4705119A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1986 |
| Grant date | Nov 10, 1987 |
| Priority date | — |
| Expiry date | Aug 29, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An annular air-hammer apparatus for drilling holes incorporates a hollow cylindrical case with a stepped bore which has inlet and outlet ports. A rock-cutting tool with an axial opening is fitted to the case at the forward end thereof. A chips-receiving sleeve and a stepped ring-shaped hammer are located inside the case, whereby the hammer forms a working-stroke chamber with the case and an idle-stroke chamber with the case, the rock-cutting tool and the chips-receiving sleeve. The chips-receiving sleeve has a cylindrical protuberance at its upper end which interacts with the hammer when this is in its topmost position. A channel is provided in the idle-stroke chamber at that side thereof which faces the upper end face of the hammer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.