Issued Patents All Time
Showing 1–9 of 9 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5407021 | Down-the-hole hammer drill having reverse circulation | Matthew Floyd Shofner, Faisal J. Yousef, Kenneth Ahlhorn | 1995-04-18 |
| 5163523 | Screw thread structure for percussion drill driver sub and case | Faisal J. Yousef, Joel Ham, David Mildren | 1992-11-17 |
| 5090500 | Replaceable wear sleeve for percussion drill | Faisal J. Yousef | 1992-02-25 |
| 5060740 | Screw thread coupling | Faisal J. Yousef, Joel Ham, David Mildren | 1991-10-29 |
| 5056611 | Screw thread structure | Faisal J. Yousef, Joel Ham, David Mildren | 1991-10-15 |
| 4867015 | Rock drilling bit and a method of producing the same | Joseph J. Portugal, Pual S. Kuzniar | 1989-09-19 |
| 4761191 | Method of forming closely sized openings | George O. Keller, Joseph J. Portugal | 1988-08-02 |
| 4756373 | Rock drilling bit and a method of producing the same | Joseph J. Portugal, Paul S. Kuzniar | 1988-07-12 |
| 4568393 | Carburized high chrome liner | William D. Van Arnam, III | 1986-02-04 |