Granted Patent
Utility
US 4,235,477 · App. 06/020,676
Variable load valve device
Inventor:
James E. Hart
Patented Case
View Patent ↗
Granted: Nov 25, 1980
Filed: Mar 15, 1979
Inventor
James E. Hart
Assignee (at issue)
American Standard Inc.
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.