Granted Patent
Utility
US 6,401,409 · App. 09/085,540
Underground storm shelter
Inventor:
Michael C. Martin
Patented Case
View Patent ↗
Granted: Jun 11, 2002
Filed: May 27, 1998
Inventor
Michael C. Martin
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.