Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5653191 | Pressure indicator | Craig Calhoun | 1997-08-05 |
| 5488946 | Emergency breathing device for opening cartridges | Craig Calhoun | 1996-02-06 |
| 4222693 | Precision drafting instrument | Eugene E. Zang, Joe S. Sheck | 1980-09-16 |