Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4368805 | Hydraulic control unit for elevators | — | 1983-01-18 |
| 4363380 | Elevator and method of lifting | Elmer J. Simpson | 1982-12-14 |
| 4345507 | Elevator fluid flow control valve | Elmer J. Simpson | 1982-08-24 |