Patents by Inventor Genji Hirata

Genji Hirata 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).

  • Control circuit having double-pole double-throw switching device for electrically powered tool
    Patent number: 5237248
    Abstract: A control circuit for use in an electrically powered tool, such as a screw driver, includes a double-pole double-throw (DPDT) relay switch having two wiper contacts movable between ON and OFF positions. A motor is connected to a power supply through the DPDT relay switch. To stop the rotations of the motor, the two wiper contacts trip from ON positions to OFF positions in ganged fashion. With the use of DPDT relay switch, even if one of the two wiper contacts undergoes chattering actions at its OFF position, the remaining wiper contact allows a large braking current to flow in a closed loop, whereby contacts of the DPDT relay switch are prevented from being melted caused by the braking current.
    Type: Grant
    Filed: March 27, 1992
    Date of Patent: August 17, 1993
    Assignee: Hitachi Koki Co., Ltd.
    Inventors: Shigeru Honma, Genji Hirata, Takahito Ishizuka, Toshio Mizoguchi