Granted Patent
Utility
US 4,263,879 · App. 06/008,275
Water heater
Inventor:
John R. Lindahl
Patented Case
View Patent ↗
Granted: Apr 28, 1981
Filed: Feb 1, 1979
Inventor
John R. Lindahl
Assignee (at issue)
State Industries, 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.