Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5207298 | Elevator rotary door interlock | Richard E. Kulak, Christian G. Tonna | 1993-05-04 |
| 5203431 | Elevator rotary lost door interlock | Richard E. Kulak, Christian G. Tonna | 1993-04-20 |