Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 8037951 | Cutter having shaped working surface with varying edge chamfer | Yuelin Shen, Youhe Zhang | 2011-10-18 |
| 7726420 | Cutter having shaped working surface with varying edge chamfer | Yuelin Shen, Youhe Zhang | 2010-06-01 |
| 6698538 | Drill bit having adjustable total flow area | Michael G. Azar, John (Youhe) Zhang | 2004-03-02 |