Granted Patent
Utility
US 4,629,002 · App. 06/789,234
Equalizing means for a subsurface well safety valve
Inventor:
Ronald E. Pringle
Patented Case
View Patent ↗
Granted: Dec 16, 1986
Filed: Oct 18, 1985
Inventor
Ronald E. Pringle
Assignee (at issue)
Camco 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.