Granted Patent
Utility
US 4,535,959 · App. 06/404,182
Vital solid state relay for railroad alternating current track circuits
Inventor:
Heinz Gilcher
Patented Case
View Patent ↗
Granted: Aug 20, 1985
Filed: Aug 2, 1982
Inventor
Heinz Gilcher
Assignee (at issue)
American Standard Inc.
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.