Granted Patent
Utility
US 4,570,725 · App. 06/575,556
Drill bit cutter
Inventors:
Terry R. Matthias, John D. Barr
Patented Case
View Patent ↗
Granted: Feb 18, 1986
Filed: Jan 31, 1984
Inventors
Terry R. Matthias
John D. Barr
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.