Granted Patent
Utility
US 4,553,733 · App. 06/458,556
Zone control valve
Inventor:
Michael D. West
Patented Case
View Patent ↗
Granted: Nov 19, 1985
Filed: Jan 17, 1983
Inventor
Michael D. West
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.