Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4998776 | Shield tunneling with optional section and machine | Shohei Chida, Masami Kozaki, Chiyoaki Ono, Seiji Iwasa, Taizou Fukunaga +1 more | 1991-03-12 |
| 4721339 | Rock crushing device and a method thereof | Mituya Sakai, Kenji Hagimori | 1988-01-26 |