Granted Patent
Utility
US 4,854,640 · App. 07/167,523
Apparatus for raising seat of chair
Inventor:
Toshio Yokoyama
Patented Case
View Patent ↗
Granted: Aug 8, 1989
Filed: Mar 14, 1988
Inventor
Toshio Yokoyama
Assignee (at issue)
Kabushikikaisya Kotobuki
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.