Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4840171 | Oxygen supply unit having an oxygen generator | Frank Joseph Schulz, Siegfried Preininger | 1989-06-20 |
| 4836197 | Folded protective hood having an oxygen mask | Frank Joseph Schulz, Wolfgang Marqardt | 1989-06-06 |
| 4807614 | Protective hood | Carl-Ernst van der Smissen | 1989-02-28 |