Granted Patent
Utility
US 4,519,457 · App. 06/580,684
Oil well standing valve
Inventors:
Ronald A. Holland, Harold L. Petrie, John R. Brennan, Frederick C. Christ
Patented Case
View Patent ↗
Granted: May 28, 1985
Filed: Feb 16, 1984
Inventors
Ronald A. Holland
Harold L. Petrie
John R. Brennan
Frederick C. Christ
Assignee (at issue)
Armco 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.