Granted Patent
Utility
US 4,260,129 · App. 06/037,059
Rotary spherical plug valve
Inventor:
Heinz Groenefeld
Patented Case
View Patent ↗
Granted: Apr 7, 1981
Filed: May 8, 1979
Inventor
Heinz Groenefeld
Assignee (at issue)
Honeywell 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.