Granted Patent
Utility
US 4,951,707 · App. 07/335,725
Seal for a pump valve
Inventor:
Jerry E. Johnson
Patented Case
View Patent ↗
Granted: Aug 28, 1990
Filed: Apr 10, 1989
Inventor
Jerry E. Johnson
Assignee (at issue)
National Oilwell, 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.