Granted Patent
Utility
US 4,550,791 · App. 06/719,027
Two-prong rotary bit, especially for use with roof drills, and insert therefor
Inventor:
Edmund Isakov
Patented Case
View Patent ↗
Granted: Nov 5, 1985
Filed: Apr 3, 1985
Inventor
Edmund Isakov
Assignee (at issue)
KENNAMETAL INC.
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.