Granted Patent
Utility
US 4,640,375 · App. 06/578,182
Drill bit and cutter therefor
Inventors:
John D. Barr, John M. Fuller
Patented Case
View Patent ↗
Granted: Feb 3, 1987
Filed: Feb 8, 1984
Inventors
John D. Barr
John M. Fuller
Assignee (at issue)
NL Industries, 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.