Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4848476 | Drill bit having offset roller cutters and improved nozzles | Paul E. Pastusek | 1989-07-18 |
| 4848489 | Drag drill bit having improved arrangement of cutting elements | — | 1989-07-18 |
| 4794994 | Drag drill bit having improved flow of drilling fluid | Percy W. Schumacher | 1989-01-03 |