Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5012621 | Lift shaft apparatus | John R. Prewer | 1991-05-07 |
| 4986040 | Modular elevator shaft | John R. Prewer | 1991-01-22 |
| 4986041 | Prefabricated elevator shaft modules | John R. Prewer | 1991-01-22 |