Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4534056 | Voice-recognition elevator security system | Michal M. Feilchenfeld, Roger Graham Byford | 1985-08-06 |
| 4490775 | Universal programmable interface | — | 1984-12-25 |
| 4436185 | Elevator system | Richard H. Ludwig, Alan L. Husson, Linus R. Dirnberger, Marjorie J. Polis | 1984-03-13 |
| 4317506 | Elevator system | Richard H. Ludwig | 1982-03-02 |