Issued Patents 1989
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4856936 | Form for concrete-placement tunnel lining | Volker Hentschel, Clemens Versteegen, Jens Gloyer | 1989-08-15 |
| 4854776 | Process and apparatus for lining a tunnel with concrete | Volker Hentschel, Clemens Versteegen, Olaf Mahmens | 1989-08-08 |
| 4848963 | Earth pressure shield | Hans-Jurgen Flunker, Gert Wittneben, Otto Braach | 1989-07-18 |
| 4844656 | Earth pressure shield | Otto Braach | 1989-07-04 |
| 4820458 | Process for continuously lining a tunnel with extruded concrete | Gunnar Lah, Otto Braach | 1989-04-11 |