Issued Patents All Time
Showing 1–6 of 6 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5299448 | Positive pressure test apparatus for facepiece respirator | Joseph Z. Zdrok, Keith Simpson | 1994-04-05 |
| 4921512 | Filter element | June E. Brissette | 1990-05-01 |
| D286213 | Dual filter respirator | Joseph Z. Zdrok | 1986-10-14 |
| 4600002 | Disposable respirator | Joseph Z. Zdrok | 1986-07-15 |
| 4592350 | Respirator | Joseph Z. Zdrok | 1986-06-03 |
| D270957 | Respirator | Joseph Z. Zdrok | 1983-10-11 |