Granted Patent
Utility
US 4,574,895 · App. 06/566,962
Solid head bit with tungsten carbide central core
Inventors:
George E. Dolezal, Joseph L. Kelly, Jr.
Patented Case
View Patent ↗
Granted: Mar 11, 1986
Filed: Dec 29, 1983
Inventors
George E. Dolezal
Joseph L. Kelly, Jr.
Assignee (at issue)
Hughes Tool Company - USA
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.