Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4856936 | Form for concrete-placement tunnel lining | Clemens Versteegen, Jens Gloyer, Siegmund Babendererde | 1989-08-15 |
| 4854776 | Process and apparatus for lining a tunnel with concrete | Clemens Versteegen, Olaf Mahmens, Siegmund Babendererde | 1989-08-08 |