Granted Patent
Utility
US 4,609,387 · App. 06/687,512
Collapsible support cage for vacuum cleaner filter
Inventors:
Robert C. Berfield, Robert L. Crevling, Jr.
Patented Case
View Patent ↗
Granted: Sep 2, 1986
Filed: Dec 28, 1984
Inventors
Robert C. Berfield
Robert L. Crevling, Jr.
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.