Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4848963 | Earth pressure shield | Siegmund Babendererde, Hans-Jurgen Flunker, Gert Wittneben | 1989-07-18 |
| 4844656 | Earth pressure shield | Siegmund Babendererde | 1989-07-04 |
| 4820458 | Process for continuously lining a tunnel with extruded concrete | Siegmund Babendererde, Gunnar Lah | 1989-04-11 |