DZ

Defa Zeng

Overall (All Time): #1,973,201 of 4,157,543Top 50%
2
Patents All Time

Issued Patents All Time

Patent #TitleCo-InventorsDate
9828806 Roller bit for rock breaking by rotary cutting Liang Zhang, Shu Li, Jialin Tian 2017-11-28
9562398 Modular cutting-teeth drill bit with controllable drilling specific pressure Liang Zhang, Shu Li, Jialin Tian 2017-02-07