Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 8960372 | Elevator car door interlock | Anthony Frank Hamlett, Sang Mu Choi, Brian Chapman, Sang-Hyuk Lee, Chet Willoughby +2 more | 2015-02-24 |
| 6684573 | Elevator door sill assembly | Eugene Ulm | 2004-02-03 |
| 6220396 | Door restrictor apparatus for elevators | — | 2001-04-24 |