Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4878548 | Nozzle retention system for a drill bit | Robert Iversen, Craig R. Hyland, Kenneth D. Enever, Steven R. Radford | 1989-11-07 |
| 4875531 | Core drilling tool with direct drive | Johann Biehl | 1989-10-24 |
| 4854403 | Stabilizer for deep well drilling tools | Hans Schillinger | 1989-08-08 |