Granted Patent
Utility
US 4,263,587 · App. 06/028,388
Liquid level control system
Inventor:
Robert S. John
Patented Case
View Patent ↗
Granted: Apr 21, 1981
Filed: Apr 9, 1979
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.