Granted Patent
Utility
US 4,248,404 · App. 06/065,222
Dual seal butterfly valve
Inventor:
Holliday L. Goldman
Patented Case
View Patent ↗
Granted: Feb 3, 1981
Filed: Aug 9, 1979
Inventor
Holliday L. Goldman
Assignee (at issue)
Allis-Chalmers 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.