Patents by Inventor Machiko Ishizaka

Machiko Ishizaka 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).

  • Dustproof mask
    Patent number: 5941244
    Abstract: A dustproof mask comprises a filter unit disposed inside a mask cover. The filter unit is provided with a baggy filter having an inhalation hole in a position corresponding to a mouth of a user. A boundary plate disposed adjacent the filter unit has vent holes opposing the inhalation hole. The user can only take in clean open air through the filter when the user inhales open air through the mouth and the user can only exhale inner air through the nostrils.
    Type: Grant
    Filed: July 28, 1998
    Date of Patent: August 24, 1999
    Assignee: Mitsumasa CHINO
    Inventors: Tomohiro Yamazaki, Minako Yamazaki, Machiko Ishizaka