Granted Patent
Utility
US 6,796,547 · App. 10/079,295
Collapsible duct
Inventor:
Robert B. Washburn
Patented Case
View Patent ↗
Granted: Sep 28, 2004
Filed: Feb 20, 2002
Inventor
Robert B. Washburn
Assignee (at issue)
Arnco
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.