Granted Patent
Utility
US 6,249,933 · App. 09/383,351
Pump having sealless shaft
Inventor:
Robert C. Berfield
Patented Case
View Patent ↗
Granted: Jun 26, 2001
Filed: Aug 26, 1999
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.