Apparatus and method for enlarging underground arcuate bore holes
US4117895A · kind A · utility
57Cited by
5References
37Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1977 |
| Grant date | Oct 3, 1978 |
| Priority date | — |
| Expiry date | Mar 30, 1997 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/046
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A hole-opener and a hole-opener apparatus is provided for enlarging a pilot hole of the inverted arcuate type which bypasses an obstacle, the pilot hole having an entrance and terminal end, both ends usually being accessible to surface drilling equipment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.