Granted Patent
Utility
US 4,297,740 · App. 06/009,012
Protective relaying apparatus
Inventor:
John E. Hagberg
Patented Case
View Patent ↗
Granted: Oct 27, 1981
Filed: Feb 5, 1979
Inventor
John E. Hagberg
Assignee (at issue)
Westinghouse Electric Company LLC
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.