Patents by Inventor Kazuki Niitsu

Kazuki Niitsu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5351490
    Abstract: A cryogenic refrigerator comprises a compressor including a compressor housing within which a cylinder is mounted, and a piston reciprocal within the cylinder, and a cold finger including a low temperature cylinder within which a displacer is reciprocable, and a regenerater mounted within the displacer. A plurality of flat piston suspension springs include a plurality of spiral slits to provide a plurality of spiral arms deflectable as the piston is reciprocated within the compressor cylinder. A plurality of annular inner retainers are secured to the piston and adapted to sandwich the inner peripheral edges of the piston suspension springs. A plurality of annular outer retainers are secured to the compressor housing and include a plurality of projections extending inwardly from the outer ends of the spiral slits to sandwich the outer peripheral edges of the flat piston suspension springs.
    Type: Grant
    Filed: January 28, 1993
    Date of Patent: October 4, 1994
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Tatsuru Ohishi, Kazuki Niitsu, Hiroyuki Kiyota, Nobuo Fujii, Yoshihiro Katagishi, Takeshi Miyazawa