Granted Patent
Utility
US 6,196,597 · App. 09/250,498
Heating duct
Inventor:
James A. Karnes
Patented Case
View Patent ↗
Granted: Mar 6, 2001
Filed: Feb 16, 1999
Inventor
James A. Karnes
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.