Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6682078 | Ring groove for oil ring with coil expander of piston | Hideshi Hitosugi, Nobuyuki Murakami | 2004-01-27 |
| 6547251 | Ring groove for oil ring with coil expander of piston | Hideshi Hitosugi, Nobuyuki Murakami | 2003-04-15 |