Granted Patent
Utility
US 4,218,790 · App. 06/036,669
Box spring assembly with improved stiffness characteristics
Inventor:
Ned W. Mizelle
Patented Case
View Patent ↗
Granted: Aug 26, 1980
Filed: May 7, 1979
Inventor
Ned W. Mizelle
Assignee (at issue)
Hoover Universal, 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.