Granted Patent
Utility
US 4,834,176 · App. 07/180,128
Well valve
Inventor:
James B. Renfroe, Jr.
Patented Case
View Patent ↗
Granted: May 30, 1989
Filed: Apr 11, 1988
Inventor
James B. Renfroe, Jr.
Assignee (at issue)
Otis Engineering 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.