Granted Patent
Utility
US 4,297,208 · App. 06/207,204
Inclined helical flight conveyor
Inventor:
Robert F. Christian
Patented Case
View Patent ↗
Granted: Oct 27, 1981
Filed: Nov 14, 1980
Inventor
Robert F. Christian
Assignee (at issue)
Jude Engineering, 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.