Granted Patent
Utility
US 6,508,618 · App. 09/788,780
Pump having dynamic shaft seal
Inventor:
Robert C. Berfield
Patented Case
View Patent ↗
Granted: Jan 21, 2003
Filed: Feb 20, 2001
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.