DZ

Defa Zeng

Overall (2017): #157,852 of 506,227Top 35%
2
Patents 2017

Issued Patents 2017

Showing 1–2 of 2 patents

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