Granted Patent
Utility
US 4,281,818 · App. 06/154,545
Replaceable adjustable butterfly valve seat
Inventors:
John P. Cunningham, Dezso Szilagyi
Patented Case
View Patent ↗
Granted: Aug 4, 1981
Filed: May 29, 1980
Inventors
John P. Cunningham
Dezso Szilagyi
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.