Granted Patent
Utility
US 4,982,240 · App. 07/508,170
Cleaning device
Inventor:
Masaru Nakano
Patented Case
View Patent ↗
Granted: Jan 1, 1991
Filed: Apr 12, 1990
Inventor
Masaru Nakano
Assignee (at issue)
HITACHI, LTD.
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.