Granted Patent
Utility
US 4,912,306 · App. 07/322,668
Electric resistance heater
Inventors:
Frederick G. J. Grise, John A. Martstiller, Paul H. Bodensiek
Patented Case
View Patent ↗
Granted: Mar 27, 1990
Filed: Mar 13, 1989
Inventors
Frederick G. J. Grise
John A. Martstiller
Paul H. Bodensiek
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.