Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D304505 | Underwater pool cleaning apparatus | Robert W. Maier, Charles J. Patterson, John Leavitt Gard, Herman E. Frentzel | 1989-11-07 |
| 4817991 | Safety fitting for a vacuum orifice in a swimming pool | Herman E. Frentzel | 1989-04-04 |