Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6000878 | Cover for underground structures | Hiroyoshi Takada, Kyozo Sahara | 1999-12-14 |
| 5997212 | Cover for underground structures, body thereof and frame therefor | Hiroyoshi Takada, Kyozo Sahara, Atsushi Nishitani, Koji Terada | 1999-12-07 |