Granted Patent
Utility
US 4,608,931 · App. 06/326,796
Filament wound railway hopper car
Inventors:
Douglas C. Ruhmann, Ralph A. Britton, James D. Mundloch, Frederick E. Vorwerk
Patented Case
View Patent ↗
Granted: Sep 2, 1986
Filed: Dec 3, 1981
Inventors
Douglas C. Ruhmann
Ralph A. Britton
James D. Mundloch
Frederick E. Vorwerk
Assignee (at issue)
ACF Industries Incorporated
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.