Granted Patent
Utility
US 5,074,533 · App. 07/505,703
Endothermic furnace
Inventor:
Russel L. Frantz
Patented Case
View Patent ↗
Granted: Dec 24, 1991
Filed: Apr 6, 1990
Inventor
Russel L. Frantz
Assignee (at issue)
Monroe Auto Equipment Company
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.