Annular air-hammer apparatus for drilling holes
US4722403A · kind A · utility
3Cited by
7References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1986 |
| Grant date | Feb 2, 1988 |
| Priority date | — |
| Expiry date | Aug 5, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/12
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
The annular air-hammer apparatus for drilling holes comprises a shell hav fitted co-axially therein a chips-receiving sleeve, a hollow cylindrical case, and a ring-shaped hammer capable of reciprocating back and forth. The lower part of the shell accommodates a rock-cutting tool capable of moving axially with at least one blow-off passage formed by at least a single longitudinal groove made on the outer cylindrical surface of the rock-cutting tool. With the rock-cutting tool in its uppermost position, the blow-off passage communicates with an outlet space provided between the shell and the case.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.