Issued Patents 1989
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4867236 | Compact casing tongs for use on top head drive earth drilling machine | Jerry K. Lingafelter | 1989-09-19 |
| 4842250 | Line reeving system for earth drilling machine | Clyde A. Willis | 1989-06-27 |
| 4830119 | Top head drive cooling system | Clyde A. Willis | 1989-05-16 |
| 4821814 | Top head drive assembly for earth drilling machine and components thereof | Clyde A. Willis | 1989-04-18 |
| 4815546 | Top head drive assembly with axially movable quill | Clyde A. Willis | 1989-03-28 |