Granted Patent
Utility
US 4,418,709 · App. 06/323,001
Unloading valve for hi-lo-hydraulic system
Inventor:
Arthur Hirsch
Patented Case
View Patent ↗
Granted: Dec 6, 1983
Filed: Nov 19, 1981
Inventor
Arthur Hirsch
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.