Granted Patent
Utility
US 4,624,428 · App. 06/652,546
Spring rail frog
Inventor:
Earl E. Frank
Patented Case
View Patent ↗
Granted: Nov 25, 1986
Filed: Sep 20, 1984
Inventor
Earl E. Frank
Assignee (at issue)
Abex 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.