Drill shoe
US4715455A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1986 |
| Grant date | Dec 29, 1987 |
| Priority date | — |
| Expiry date | Oct 14, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/40
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A drill shoe adapted to fit onto a drill pipe of external diameter d.sub.e and internal diameter d.sub.i comprises an externally stepped cutting surface comprising a plurality of steps, the diameters of the steps increasing as they progress away from the tip of the shoe. The maximum external diameter D.sub.e of the shoe is greater than the external diameter d.sub.e of the drill pipe. The shoe also comprises an internal, substantially cylindrical, inner surface of diameter D.sub.i, D.sub.i being less than the internal diameter d.sub.i of the drill pipe. The shoe is suitable for use in a vibratory drill string for obtaining cores from unconsolidated geological formations, such as soil, sand and gravel or similar materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.