Granted Patent
Utility
US 6,138,412 · App. 08/842,994
Door opener and closer
Inventors:
William H. Rieckmann, Wayne W. Bostad
Patented Case
View Patent ↗
Granted: Oct 31, 2000
Filed: Apr 25, 1997
Inventors
William H. Rieckmann
Wayne W. Bostad
Assignee (at issue)
Chase Industries, 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.