Granted Patent
Utility
US 4,683,880 · App. 06/494,845
Toxic fume protective hood and method of construction
Inventor:
Bertil R. L. Werjefelt
Patented Case
View Patent ↗
Granted: Aug 4, 1987
Filed: May 16, 1983
Inventor
Bertil R. L. Werjefelt
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND COMPANY
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.