Granted Patent
Utility
US 4,313,869 · App. 06/151,398
Composition friction element for a railroad brake shoe
Inventor:
John B. Littlefield
Patented Case
View Patent ↗
Granted: Feb 2, 1982
Filed: May 19, 1980
Inventor
John B. Littlefield
Assignee (at issue)
AMSTED 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.