Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4468906 | Blocks or bricks for the construction of a two-shell tile stove | Herbert Spirk | 1984-09-04 |
| 4433523 | Block or brick for the construction of a two-shell tile stove | Herbert Spirk | 1984-02-28 |