Granted Patent
Utility
US 4,643,668 · App. 06/624,014
Hot surface direct ignition system for gas furnaces
Inventor:
Frederick J. Geary
Patented Case
View Patent ↗
Granted: Feb 17, 1987
Filed: Jun 25, 1984
Inventor
Frederick J. Geary
Assignee (at issue)
ROBERTSHAW CONTROLS PRIVATE LIMITED
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.