Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4840137 | Liquid level gauging apparatus | Thomas E. Beauvais, Vincent G. Krenke, Donald J. Mattis | 1989-06-20 |
| 4803320 | Electric switch construction | Donald J. Mattis | 1989-02-07 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4840137 | Liquid level gauging apparatus | Thomas E. Beauvais, Vincent G. Krenke, Donald J. Mattis | 1989-06-20 |
| 4803320 | Electric switch construction | Donald J. Mattis | 1989-02-07 |