Granted Patent
Utility
US 4,301,489 · App. 06/105,082
Arcless tap changer utilizing static switching
Inventor:
Frederick A. Stich
Patented Case
View Patent ↗
Granted: Nov 17, 1981
Filed: Dec 19, 1979
Inventor
Frederick A. Stich
Assignee (at issue)
Siemens-Allis
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.