Granted Patent
Utility
US 4,619,283 · App. 06/822,441
Stem seal for tapered lubricated plug valves
Inventors:
E. Frederick Schoeneweis, Donn W. Duffey
Patented Case
View Patent ↗
Granted: Oct 28, 1986
Filed: Jan 27, 1986
Inventors
E. Frederick Schoeneweis
Donn W. Duffey
Assignee (at issue)
Rockwell International Corporation
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.