Granted Patent
Utility
US 5,983,892 · App. 08/878,998
Device for improving breathing
Inventor:
W. Keith Thornton
Patented Case
View Patent ↗
Granted: Nov 16, 1999
Filed: Jun 19, 1997
Inventor
W. Keith Thornton
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.