IP Library › Granted Patent US 4,637,578
Granted Patent Utility
US 4,637,578 · App. 06/545,488

Railroad frog having movable wing rails

Inventor: Earl E. Frank
Patented Case View Patent ↗
Granted: Jan 20, 1987 Filed: Oct 26, 1983
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.

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Quick Facts
Patent No.
US 4,637,578
App. No.
06/545,488
Filed
1983-10-26
Granted
1987-01-20
Kind
A