Granted Patent
Utility
US 4,556,832 · App. 06/587,669
Control valve apparatus
Inventor:
John P. Rollins
Patented Case
View Patent ↗
Granted: Dec 3, 1985
Filed: Mar 8, 1984
Inventor
John P. Rollins
Assignee (at issue)
Duff-Norton 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.