Granted Patent
Utility
US 4,636,995 · App. 06/764,167
Mud pressure control system
Inventors:
Michael K. Russell, Anthony Russell
Patented Case
View Patent ↗
Granted: Jan 13, 1987
Filed: Aug 9, 1985
Inventors
Michael K. Russell
Anthony 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.