Issued Patents All Time
Showing 26–28 of 28 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D320281 | Underground service vault | — | 1991-09-24 |
| D319883 | Ring for a manhole cover | Robert O. Andreasen | 1991-09-10 |
| D309024 | Observation monitoring well manhole cover | — | 1990-07-03 |