Granted Patent
Utility
US 4,842,449 · App. 07/072,412
Pneumatic evacuator-filler for grain drill hopper
Inventor:
Marvin L. Nelson
Patented Case
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Granted: Jun 27, 1989
Filed: Jul 13, 1987
Inventor
Marvin L. Nelson
Assignee (at issue)
J. I. Case 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.