Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4696600 | Method and apparatus for modifying the cross-sectional profile of an adit, tunnel or the like | Willi Steufmehl, Wolfgang Krappen | 1987-09-29 |
| 4548282 | Method for sinking boreholes | Heinz P. Vogts | 1985-10-22 |
| 4396072 | Method and apparatus for producing a drill hole | Willi Steufmehl | 1983-08-02 |