Granted Patent
Utility
US 4,719,664 · App. 06/931,714
Swivable caster
Inventor:
Robert C. Berfield
Patented Case
View Patent ↗
Granted: Jan 19, 1988
Filed: Nov 17, 1986
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.