Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4812674 | Safety gate limit switch using Hall effect transducer | Richard T. Guttman, David Mark Pendley, William C. Keys | 1989-03-14 |
| 4463399 | Circuit for intrinsically safe pilot light | David R. Matherly | 1984-07-31 |