Granted Patent
Utility
US 4,997,361 · App. 07/365,476
Hot surface direct ignition system for gas furnaces
Inventor:
Frederick J. Geary
Patented Case
View Patent ↗
Granted: Mar 5, 1991
Filed: Jun 13, 1989
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.