Patents by Inventor Katsumi Yamashita

Katsumi Yamashita 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: 5626962
    Abstract: Co-coated acicular magnetite particles each comprising:acicular magnetite particle as the core particle;a lower coating layer of Co-containing spinel ferrite having a spinel structure, which is formed on the surface of said acicular magnetite particle; andan upper coating layer of Co- and Mg-containing spinel ferrite having a spinel structure, which is formed on said lower coating layer.
    Type: Grant
    Filed: February 27, 1995
    Date of Patent: May 6, 1997
    Assignee: Toda Kogyo Corporation
    Inventors: Minoru Yamasaki, Junichi Kawano, Hideaki Sadamura, Katsumi Yamashita
  • Patent number: 5531922
    Abstract: Disclosed herein are granulated particles for magnetic particles for magnetic recording, comprising: acicular ferric hydroxide oxide particles or acicular iron oxide particles; and at least one selected from the group consisting of semisynthetic starch and semisynthetic cellulose and having a bulk density of not less than 0.3 g/cm.sup.3 and a powdering ratio of not more than 40%, and a process for producing the granulated particles, and magnetic particles obtained from such granulated particles.
    Type: Grant
    Filed: September 12, 1995
    Date of Patent: July 2, 1996
    Assignee: Toda Kogyo Corporation
    Inventors: Kenji Okinaka, Yasutaka Ota, Kohji Mori, Hirofumi Kawasaki, Masayuki Uegami, Akio Mishima, Katsumi Yamashita, Minoru Yamasaki, Manabu Matsumoto, Kunihiro Kouchi, Hiroki Kamon
  • Patent number: 5399278
    Abstract: Disclosed herein are a process for producing acicular goethite particles comprising the steps of: blowing an oxygen-containing gas into a ferrous salt reaction solution containing colloidal ferrous hydroxide or iron-containing colloidal precipitates which is obtained by reacting an aqueous ferrous salt solution with less than one equivalent of an aqueous alkali hydroxide solution and/or an aqueous alkali carbonate solution based on Fe.sup.2 + in said aqueous ferrous salt solution so as to oxidize said colloidal ferrous hydroxide or iron-containing colloidal precipitates and to produce acicular goethite nucleus particles, adding to the resultant aqueous ferrous salt reaction solution containing said acicular goethite nucleus particles not less than one equivalent of an aqueous alkali carbonate solution based on Fe.sup.
    Type: Grant
    Filed: February 25, 1993
    Date of Patent: March 21, 1995
    Assignee: Toda Kogyo Corp.
    Inventors: Katsumi Yamashita, Tosiharu Harada, Haruki Kurokawa, Kazuhisa Inaba, Hideaki Sadamura, Tomohisa Moriya, Junichi Kawano
  • Patent number: 5294492
    Abstract: Disclosed herein is a process for producing acicular magnetic iron oxide particles comprising the steps of: mixing an aqueous dispersion of acicular magnetic iron oxide particles with an aqueous solution of a Co salt and an alkaline aqueous solution, or an aqueous solution of a Co salt, an aqueous solution of an Fe(II) salt and and an alkaline aqueous solution; and heat-treating the alkaline suspension solution obtained at 50.degree. to 100.degree. C.
    Type: Grant
    Filed: July 2, 1991
    Date of Patent: March 15, 1994
    Assignee: Toda Kogyo Corp.
    Inventors: Hiroshi Oka, Kazuaki Kouziro, Toshitada Shigemura, Tomohisa Moriya, Katsumi Yamashita, Kazushi Takama, Takanobu Uemoto, Kazuhiro Fujita
  • Patent number: 4541145
    Abstract: A clamping device for clamping a split heat-shrinkable sleeve placed around the joint between the core conductors of two communication cables which are to be joined or spliced together. The sleeve has two upstanding lugs or flanges on either side of the split in the sleeve. The holding strips are placed against the outer surface of the lugs. Each strip consists of two foldable link assemblies joined to opposite ends of a straight, rigid center portion or line. A connecting rod is initially inserted through sleeves on each strip to keep the strip straight during placement against the lugs. Clamping springs are rotatably mounted on one strip, and, after placement of the strip, the springs are rotated over both strips, thereby forcing the lugs into contact with each other. The rods are then removed.
    Type: Grant
    Filed: November 29, 1983
    Date of Patent: September 17, 1985
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Mitomu Sato, Toshikazu Nakatani, Katsumi Yamashita, Terumi Ogata