Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4262759 | Combination seal and pressure relief valve for sealed drill string unit | James W. Young | 1981-04-21 |
| 4254839 | Radial force anti-extrusion device for sealed drill string unit | Leo A. Martini | 1981-03-10 |