Granted Patent
Utility
US 4,304,986 · App. 06/170,778
Electric heating apparatus for foundry ladle
Inventor:
William E. Olson, Jr.
Patented Case
View Patent ↗
Granted: Dec 8, 1981
Filed: Jul 21, 1980
Inventor
William E. Olson, Jr.
Assignee (at issue)
ESCO GROUP 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.