Granted Patent
Utility
US 4,350,209 · App. 06/270,993
Hydraulic draft control valve
Inventor:
John O'Connor
Patented Case
View Patent ↗
Granted: Sep 21, 1982
Filed: Jun 5, 1981
Inventor
John O'Connor
Assignee (at issue)
Allis-Chalmers Corporation
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.