Granted Patent
Utility
US 4,390,793 · App. 06/236,842
Electronic liquid level control apparatus
Inventor:
Robert S. John
Patented Case
View Patent ↗
Granted: Jun 28, 1983
Filed: Feb 23, 1981
Inventor
Robert S. John
Assignee (at issue)
International Telephone and Telegraph Corporation
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.