Granted Patent
Utility
US 4,637,185 · App. 06/621,957
Trench ducts
Inventor:
Timothy S. Bowman
Patented Case
View Patent ↗
Granted: Jan 20, 1987
Filed: Jun 18, 1984
Inventor
Timothy S. Bowman
Assignee (at issue)
BUTLER MANUFACTURING 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.