Granted Patent
Utility
US 4,398,696 · App. 06/316,798
Butterfly valve
Inventors:
Dezso Szilagyi, John P. Cunningham, Robert L. Bowlby
Patented Case
View Patent ↗
Granted: Aug 16, 1983
Filed: Oct 30, 1981
Inventors
Dezso Szilagyi
John P. Cunningham
Robert L. Bowlby
Assignee (at issue)
Federal Signal 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.