Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4863313 | Method for lining tunnel wall formed by shield excavation | Minoru Yamamoto | 1989-09-05 |
| 4799824 | Method of making covering wall of tunnel made by shield type excavator | Yoshihiro Takano | 1989-01-24 |