Issued Patents All Time
Showing 51–58 of 58 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5301469 | Door assembly with multiple torque rod counterbalancing | — | 1994-04-12 |
| 5205073 | Counterbalanced door assembly with reduced initial closing force | — | 1993-04-27 |
| 5136811 | Torque rod counterbalanced door assembly | — | 1992-08-11 |
| 4873791 | Torque rod operated counterbalancing hinge and door assembly | — | 1989-10-17 |
| 4729453 | Portable safety post | — | 1988-03-08 |
| 4720426 | Reflective coating for solid-state scintillator bar | August O. Englert, Charles F. Marks | 1988-01-19 |
| 4688768 | Extendable railing | — | 1987-08-25 |
| 4546855 | Safety extension for a fixed ladder with an adjustable mount | — | 1985-10-15 |