Granted Patent
Utility
US 4,339,222 · App. 06/202,533
Door locking mechanism for hopper car doors
Inventor:
Willis H. Knippel
Patented Case
View Patent ↗
Granted: Jul 13, 1982
Filed: Oct 31, 1980
Inventor
Willis H. Knippel
Assignee (at issue)
The Pullman Company LLC
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.