Granted Patent
Utility
US 4,838,838 · App. 07/173,425
Belt driving pulley having a roughened surface to reduce noise
Inventor:
Robert C. Berfield
Patented Case
View Patent ↗
Granted: Jun 13, 1989
Filed: Mar 25, 1988
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.