Granted Patent
Utility
US 4,068,021 · App. 05/664,955
Method of making gas analyzing element
Inventor:
Charles E. Allman
Patented Case
View Patent ↗
Granted: Jan 10, 1978
Filed: Mar 8, 1976
Inventor
Charles E. Allman
Assignee (at issue)
Dictaphone Corporation.
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.