Granted Patent
Utility
US 4,428,706 · App. 06/276,571
Interlock selector control valve for round bale wagon
Inventors:
L. Dennis Butler, Alan R. Askov
Patented Case
View Patent ↗
Granted: Jan 31, 1984
Filed: Jun 23, 1981
Inventors
L. Dennis Butler
Alan R. Askov
Assignee (at issue)
Sperry Corp.
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.