Granted Patent
Utility
US 4,222,863 · App. 06/005,368
Screening apparatus and method
Inventor:
Douglas L. G. Young
Patented Case
View Patent ↗
Granted: Sep 16, 1980
Filed: Jan 22, 1979
Inventor
Douglas L. G. Young
Assignee (at issue)
Ingersoll-Rand Canada, Inc.
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.