Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4844179 | Drill string stabilizer | John Forrest, William M. Stewart | 1989-07-04 |
| 4796704 | Drop ball sub-assembly for a down-hole device | John Forrest, William M. Stewart | 1989-01-10 |