Granted Patent
Utility
US 4,936,297 · App. 07/354,495
Device for the enrichment of respiratory air with oxygen
Inventors:
Rudolf Greiff, Wolfgang Rittner
Patented Case
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Granted: Jun 26, 1990
Filed: May 19, 1989
Inventors
Rudolf Greiff
Wolfgang Rittner
Assignee (at issue)
DRAGERWERK AKTIEGESELLSCHAFT
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.