Granted Patent
Utility
US 4,230,185 · App. 05/911,186
Rod operated rotary well valve
Inventor:
John V. Fredd
Patented Case
View Patent ↗
Granted: Oct 28, 1980
Filed: May 31, 1978
Inventor
John V. Fredd
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.