Granted Patent
Utility
US 4,805,358 · App. 07/043,561
Electrical trench assembly
Inventor:
Frank W. Fork
Patented Case
View Patent ↗
Granted: Feb 21, 1989
Filed: Apr 27, 1987
Inventor
Frank W. Fork
Assignee (at issue)
H. H. Robertson Company
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.