Granted Patent
Utility
US 6,357,992 · App. 09/228,634
Collapsible, powered platform for lifting wheelchair
Inventors:
Lynn O. Ringdahl, James B. Welte
Patented Case
View Patent ↗
Granted: Mar 19, 2002
Filed: Jan 11, 1999
Inventors
Lynn O. Ringdahl
James B. Welte
Assignee (at issue)
Braun Crow River, 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.