Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6702045 | Drilling apparatus | — | 2004-03-09 |
| RE36002 | Transmission sleeve for a down hole hammer | Brian T. Sanfead, Andrew Greathead | 1998-12-22 |
| 5154244 | Transmission sleeve for a down hole hammer | Brian T. Sanfead, Andrew Greathead | 1992-10-13 |
| 5085285 | Compensating ring for a down hole hammer | John Urquhart Dewar, Andrew Greathead, Brian T. Sanfead | 1992-02-04 |