Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7299887 | Roller bit with a journal pin offset from the central axis thereof | Yan Zhao | 2007-11-27 |
| 6119797 | Single cone earth boring bit | Chunling Hong, Hongmei Huang, Heng Du | 2000-09-19 |