Issued Patents 1994
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5370195 | Drill bit inserts enhanced with polycrystalline diamond | Monte Russell, Dah-Ben Liang | 1994-12-06 |
| 5305840 | Rock bit with cobalt alloy cemented tungsten carbide inserts | Dah-Ben Liang | 1994-04-26 |