Granted Patent
Utility
US 4,744,705 · App. 06/895,177
Twist drill bit
Inventor:
Koujirou Imanaga
Patented Case
View Patent ↗
Granted: May 17, 1988
Filed: Aug 11, 1986
Inventor
Koujirou Imanaga
Assignee (at issue)
Mitsubishi Kinzoku Kabushiki Kaisha
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.