Granted Patent
Utility
US 4,821,789 · App. 07/135,241
Venetian blind with improved ladder tilt drum
Inventor:
Mark R. Van Rens
Patented Case
View Patent ↗
Granted: Apr 18, 1989
Filed: Dec 21, 1987
Inventor
Mark R. Van Rens
Assignee (at issue)
Graber Industries, 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.