Granted Patent
Utility
US 4,966,199 · App. 07/363,602
Diaphragm-type center flow check valve
Inventor:
Ricky R. Ruschke
Patented Case
View Patent ↗
Granted: Oct 30, 1990
Filed: Jun 8, 1989
Inventor
Ricky R. Ruschke
Assignee (at issue)
Filtertek Inc.
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.