Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4563843 | Heat insulation window | Paul Grether, Bruno Keller | 1986-01-14 |
| 4545160 | Window | Paul Grether, Bruno Keller | 1985-10-08 |
| 4432174 | Self-supporting insulation element | Paul Grether, Bruno Keller | 1984-02-21 |