Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4877093 | Spring actuated power swivel support rollers | David B. Ford, Leroy R. Rateike | 1989-10-31 |
| 4813498 | Active counterbalance for a power swivel during well drilling | David B. Ford | 1989-03-21 |
| 4809792 | Support system for a top driven drilling unit | — | 1989-03-07 |