Granted Patent
Utility
US 4,983,803 · App. 07/448,429
Method of making a subsurface well safety valve
Inventors:
Ronald E. Pringle, Arthur J. Morris
Patented Case
View Patent ↗
Granted: Jan 8, 1991
Filed: Dec 11, 1989
Inventors
Ronald E. Pringle
Arthur J. Morris
Assignee (at issue)
Camco International, 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.