Granted Patent
Utility
US 4,535,429 · App. 06/512,308
Apparatus for signalling within a borehole while drilling
Inventors:
Anthony Russell, Michael K. Russell
Patented Case
View Patent ↗
Granted: Aug 13, 1985
Filed: Jul 11, 1983
Inventors
Anthony Russell
Michael K. Russell
Assignee (at issue)
NL Sperry-Sun, 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.