Patents by Inventor Yasuhiro Ishitsuka

Yasuhiro Ishitsuka 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).

  • Resinous disc cartridge containing an ester compound of glycerin
    Patent number: 5410440
    Abstract: A disc cartridge including a recording disc, a cartridge case in which the recording disc is housed rotatably and a head inserting opening is formed at a predetermined location, and a synthetic resin-made shutter adapted to open and close the head inserting opening in the cartridge case, wherein the cartridge case and the shutter contain an ester compound of glycerin and optionally an amine type organic compound.
    Type: Grant
    Filed: November 4, 1992
    Date of Patent: April 25, 1995
    Assignee: Hitachi Maxell, Ltd.
    Inventor: Yasuhiro Ishitsuka
  • Recording media case
    Patent number: 5373944
    Abstract: A recording media case suitable for filing recording media adapted to prevent the outer side of encased disk cartridges or the like accommodating the recording media from being exposed when the case is used while separate from a file, and thus adapted to completely protect the recording media from dust and external force, the case also having good portability.
    Type: Grant
    Filed: August 9, 1993
    Date of Patent: December 20, 1994
    Assignee: Hitachi Maxell, Ltd.
    Inventor: Yasuhiro Ishitsuka