Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4889312 | Waterstop for concrete form separator | Sunoo Ogou, Shigemichi Ishii, Sadaaki Tagomori, Yasumasa Hayashida | 1989-12-26 |
| 4816509 | Water swellable sealant | Yasumasa Hayashida, Jinichi Omi | 1989-03-28 |