Granted Patent
Utility
US 4,752,673 · App. 06/445,862
Autoregulating heater
Inventor:
John F. Krumme
Patented Case
View Patent ↗
Granted: Jun 21, 1988
Filed: Dec 1, 1982
Inventor
John F. Krumme
Assignee (at issue)
Metcal, Inc.
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.