Patents by Inventor Hisahide Nakagawa

Hisahide Nakagawa 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: 4627739
    Abstract: A bracelet type wrist watch composed of a curved body having a watch embedded therein, and a coil spring covering said curved body, thus presenting a neat appearance as an ornamental ring when worn around the wrist.
    Type: Grant
    Filed: January 31, 1985
    Date of Patent: December 9, 1986
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Ichikawa Shingo, Hisahide Nakagawa, Hayao Kano, Koji Kudo
  • Patent number: 4328570
    Abstract: In an electronic timepiece having a quartz crystal controlled standard frequency oscillator and a device which temporarily imposes a heavy load on the battery when activated, means are provided for changing a value of a circuit constant in the oscillator circuit, such as capacitance or resistance, when the load device is activated. This change in circuit constant value serves to decrease the value of the minimum battery supply voltage below which the oscillator circuit ceases to function, thereby ensuring reliable operation of the oscillator circuit when the timepiece battery voltage drops due to current being supplied to the load device.
    Type: Grant
    Filed: April 18, 1980
    Date of Patent: May 4, 1982
    Assignee: Citizen Watch Company Limited
    Inventor: Hisahide Nakagawa
  • Patent number: 4223524
    Abstract: A quartz oscillation circuit used for a time standard of an electronic timepiece, which includes an inverter operating as an amplifier, an input capacitor and an output capacitor, the capacitors having the opposite temperature characteristics to compensate changes in oscillation frequency with the variation of temperature without any increase of the power consumption.
    Type: Grant
    Filed: March 16, 1979
    Date of Patent: September 23, 1980
    Assignee: Citizen Watch Co., Ltd.
    Inventor: Hisahide Nakagawa