Granted Patent
Utility
US 4,493,339 · App. 06/374,945
Air valve for a breathing system
Inventor:
George K. Porter
Patented Case
View Patent ↗
Granted: Jan 15, 1985
Filed: May 5, 1982
Inventor
George K. Porter
Assignee (at issue)
Porter Instrument Company, 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.