Granted Patent
Utility
US 4,245,997 · App. 06/018,871
Gas measuring and warning device with indicator tube through which gas to be tested is directed
Inventor:
Peter Wiesner
Patented Case
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Granted: Jan 20, 1981
Filed: Mar 9, 1979
Inventor
Peter Wiesner
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.