Granted Patent
Utility
US 4,453,560 · App. 06/305,168
Hydraulically balanced valve mechanism
Inventors:
R. Frank Nestich, Burton L. Preston
Patented Case
View Patent ↗
Granted: Jun 12, 1984
Filed: Sep 24, 1981
Inventors
R. Frank Nestich
Burton L. Preston
Assignee (at issue)
Interpace 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.