Granted Patent
Utility
US 4,906,265 · App. 07/296,573
Filter and installation means for dry material filter for electric vacuum cleaner
Inventor:
Robert C. Berfield
Patented Case
View Patent ↗
Granted: Mar 6, 1990
Filed: Jan 12, 1989
Inventor
Robert C. Berfield
Assignee (at issue)
SHOP VAC CORPORATION
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.