Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6220167 | Excavation method by blasting | Masaaki Yamamoto, Koichi Sassa | 2001-04-24 |
| 5297582 | Method for water leakage prevention in pipeline | Hisashi Kitajima | 1994-03-29 |
| 5224742 | Method for cutting off water in pipeline and structure of connection portion in pipeline | Sinkiti Ooka, Yukio Suzuki, Hisashi Kitajima | 1993-07-06 |