Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5181800 | Mine roof anchor having adjustable resin retaining washer | John C. Stankus, Eugene H. Stewart | 1993-01-26 |
| 5082399 | Mine roof anchor having adjustable resin retaining washer and expansion shell assembly with friction reducing means | Jerry E. Frease, John C. Stankus, Eugene H. Stewart | 1992-01-21 |
| 4865489 | Mine roof anchor having adjustable resin retaining washer | John C. Stankus, Eugene H. Stewart | 1989-09-12 |