Granted Patent
Utility
US 4,775,016 · App. 07/102,173
Downhole pressure fluctuating feedback system
Inventor:
Louis H. Barnard
Patented Case
View Patent ↗
Granted: Oct 4, 1988
Filed: Sep 29, 1987
Inventor
Louis H. Barnard
Assignee (at issue)
Hughes Tool Company - USA
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.