Granted Patent
Utility
US 4,505,342 · App. 06/443,657
Drill bit
Inventors:
John D. Barr, John M. Fuller
Patented Case
View Patent ↗
Granted: Mar 19, 1985
Filed: Nov 22, 1982
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.