Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7771168 | Axial fan | Henricus Johannes Bernardus Olthof, Hendrik Fedde Van Der Spek | 2010-08-10 |
| 6761539 | Rotor blade with a reduced tip | Hendrik Fedde van der Spek | 2004-07-13 |