Granted Patent
Utility
US 4,241,740 · App. 06/017,591
Bellows type incentive spirometer
Inventor:
Joseph W. Brown
Patented Case
View Patent ↗
Granted: Dec 30, 1980
Filed: Mar 5, 1979
Inventor
Joseph W. Brown
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.