Granted Patent
Utility
US 4,875,742 · App. 07/184,738
Solenoid operated hydraulic control valve
Inventor:
Michael J. Hawker
Patented Case
View Patent ↗
Granted: Oct 24, 1989
Filed: Apr 22, 1988
Inventor
Michael J. Hawker
Assignee (at issue)
Clayton Dewandre Co., Ltd.
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.