Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4381188 | Grinding disk | Harald Helletsberger, Christof Kriegshaber, Volker Selgrad | 1983-04-26 |
| 4259089 | Grinding wheel containing grain-coated reinforcement fibers and method of making it | Harald Helletsberger | 1981-03-31 |