Patents by Inventor Yasuhisa Hirosawa

Yasuhisa Hirosawa 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: 4590529
    Abstract: A carriage device used for moving and positioning a magnetic head opposite prescribed tracks of a magnetic disk has the magnetic head mounted on a carriage which has linear motor mechanisms built integrally therein. The linear motor mechanisms incorporate coils secured to part of the carriage and permanent magnets secured aorund the coils. Guide rails serving to support the carriage within the range of the sliding motion of the coils are made of a magnetic substance.
    Type: Grant
    Filed: March 7, 1984
    Date of Patent: May 20, 1986
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Akira Nikaido, Takayasu Machida, Yasuhisa Hirosawa, Fumio Nakajima
  • Patent number: 4558244
    Abstract: The present invention provides a micro stepping motor for more accurately stepping and positioning a magnetic head in a magnetic disc system. The stepping motor has a permanent magnet type rotor and a stator encircling the rotor, the rotor having a plurality of pole teeth formed therein with a fine pitch and the stator also having a plurality of pole teeth formed therein with a fine pitch and disposed opposed to the pole teeth in the rotor, the stator pole teeth being divided into at least one pair of pole tooth groups which are out of phase relative to each other by an electrical angle of 180 degrees. A single common stator coil is provided to the pair of stator pole tooth groups. Thus, the stepping pitch of the rotor is determined by the pitch in the pole tooth groups, whereby the rotor can steppingly be driven with higher density even by the reduced number of stator coils.
    Type: Grant
    Filed: March 12, 1984
    Date of Patent: December 10, 1985
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Akira Nikaido, Takayasu Machida, Yasuhisa Hirosawa, Fumio Nakajima