Granted Patent
Utility
US 5,207,411 · App. 07/954,019
Butterfly valve assembly
Inventor:
David E. Sisk
Patented Case
View Patent ↗
Granted: May 4, 1993
Filed: Sep 30, 1992
Inventor
David E. Sisk
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.