Granted Patent
Utility
US 4,424,974 · App. 06/402,598
Ferro fluidic seal
Inventors:
Yasunaga Mitsuya, Kunio Hoshiya, Shigemitsu Oguchi, Reizo Kaneko
Patented Case
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Granted: Jan 10, 1984
Filed: Jul 28, 1982
Inventors
Yasunaga Mitsuya
Kunio Hoshiya
Shigemitsu Oguchi
Reizo Kaneko
Assignee (at issue)
Nippon Telegraph and Telephone Public Corporation
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.