Granted Patent
Utility
US 4,601,459 · App. 06/668,553
Improved butterfly valve
Inventor:
Alain B. A. Verdelet
Patented Case
View Patent ↗
Granted: Jul 22, 1986
Filed: Nov 2, 1984
Inventor
Alain B. A. Verdelet
Assignee (at issue)
Masoneilan International, 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.