Granted Patent
Utility
US 6,571,798 · App. 09/543,402
Device for improving breathing and method of constructing same
Inventor:
W. Keith Thornton
Patented Case
View Patent ↗
Granted: Jun 3, 2003
Filed: Apr 5, 2000
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.