Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5248007 | Electronic control system for stair climbing vehicle | Baxter R. Watkins, Douglas J. Littlejohn, Havard L. Staggs, Chi-Foun Kuen | 1993-09-28 |
| 5123495 | Wheelchair stair climbing control system | Douglas J. Littlejohn, Baxter R. Watkins | 1992-06-23 |