Granted Patent
Utility
US 4,518,406 · App. 06/558,680
Drain bushing
Inventors:
Richard Perkins, William C. Brady, Hellmut I. Glaser
Patented Case
View Patent ↗
Granted: May 21, 1985
Filed: Dec 6, 1983
Inventors
Richard Perkins
William C. Brady
Hellmut I. Glaser
Assignee (at issue)
Owens-Corning Fiberglas Corp.
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.