Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4645893 | Method for manufacturing spiral-welded steel pipe | Yoshito Tsuyama, Hiroyo Haga, Manabu Hanzawa | 1987-02-24 |
| 4436239 | Method and apparatus for manufacturing spiral pipe | Yoshito Tsuyama, Kazutoshi Kakita, Toshio Hirokawa | 1984-03-13 |