Granted Patent
Utility
US 6,398,184 · App. 09/750,271
Lock device and lock method for knife gate valves
Inventors:
Craig A. Sowada, Richard R. Ruegemer
Patented Case
View Patent ↗
Granted: Jun 4, 2002
Filed: Dec 29, 2000
Inventors
Craig A. Sowada
Richard R. Ruegemer
Assignee (at issue)
Federal Signal 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.