Granted Patent
Utility
US 6,401,754 · App. 09/686,819
Four way valve
Inventors:
Melvin Winquist, David Bayreuther
Patented Case
View Patent ↗
Granted: Jun 11, 2002
Filed: Oct 12, 2000
Inventors
Melvin Winquist
David Bayreuther
Assignee (at issue)
METSO AUTOMATION USA, 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.