Granted Patent
Utility
US 4,778,061 · App. 07/061,485
Air classifier apparatus
Inventor:
Robert M. Williams
Patented Case
View Patent ↗
Granted: Oct 18, 1988
Filed: Jun 15, 1987
Inventor
Robert M. Williams
Assignee (at issue)
WILLIAMS PATENT CRUSHER AND PULVERIZER COMPANY
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.