Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4246979 | Internal sleeve air release control apparatus in seismic air gun | Roy Johnston | 1981-01-27 |
| 4219098 | Internal passive air release control apparatus in seismic air gun | Roy Johnston | 1980-08-26 |