Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4838306 | Pneumatic locking valve with manual override | Derek Hopkinson | 1989-06-13 |
| 4838532 | Fluid operated clamping device including fluid pressure locking means | Derek Hopkinson | 1989-06-13 |