Granted Patent
Utility
US 4,458,710 · App. 06/374,044
Method of making a valve construction having multiple pistons
Inventor:
Marvin P. Weaver
Patented Case
View Patent ↗
Granted: Jul 10, 1984
Filed: May 3, 1982
Inventor
Marvin P. Weaver
Assignee (at issue)
ROBERTSHAW CONTROLS PRIVATE LIMITED
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.