Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D319316 | Square construction module | Jan van Weerden, Johannes Valkenburg | 1991-08-20 |
| D319108 | Rectangular construction module | Jan van Weerden, Johannes Valkenburg | 1991-08-13 |
| 4854953 | Air filter and module to be used for building up such a filter | Jan van Weerden, Johannes Valkenburg | 1989-08-08 |