Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5101863 | Rehabilitating underground pipes with expanding helically wound liner | Shigeki Fujii, Minoru Yasuhara, Masahisa Sonku | 1992-04-07 |
| 4951758 | Method of drilling a branch line aperture after internal lining of a pipeline and a water plug used in the method | Masahisa Sonku, Yukio Yoshimura, Minoru Yasuhara, Naoki Kitahashi, Harutoshi Miyazaki +1 more | 1990-08-28 |