Method of boring holes which are open at both ends in the ground
US4249620A · kind A · utility
11Cited by
9References
5Claims
0Family size
Inventor
Key dates
| Filing date | May 9, 1979 |
| Grant date | Feb 10, 1981 |
| Priority date | — |
| Expiry date | May 9, 1999 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/30
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of boring holes in the ground, which holes are open at both ends, includes forming an open-ended pilot bore by means of a first self-propelled displacement hammer of smaller diameter. Next a cable is introduced through the pilot bore and then the diameter of the pilot bore is increased to form the hole by means of a second displacement hammer of greater diameter. The second displacement hammer is guided through the pilot bore by pulling it with the cable which for this purpose is attached to the leading end of the second hammer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.