Granted Patent
Utility
US 5,238,021 · App. 08/002,136
Diaphragm operated spring loaded regulator
Inventors:
Walter W. Powell, Louis R. Castaneda
Patented Case
View Patent ↗
Granted: Aug 24, 1993
Filed: Jan 11, 1993
Inventors
Walter W. Powell
Louis R. Castaneda
Assignee (at issue)
Groth LLC
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.