Granted Patent
Utility
US 4,467,136 · App. 06/324,923
Drainable enclosure for explosion-proof electrical systems
Inventor:
Eigil Wium
Patented Case
View Patent ↗
Granted: Aug 21, 1984
Filed: Nov 25, 1981
Inventor
Eigil Wium
Assignee (at issue)
Federal Signal 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.