Issued Patents All Time
Showing 26–28 of 28 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7256371 | Temperature control method for positive temperature coefficient type heating element | John Crawford, Kevin Altschwager | 2007-08-14 |
| 6223446 | Grade/level measuring device | — | 2001-05-01 |
| 4489263 | Electronic speed control circuits | John Crawford | 1984-12-18 |