Patents by Inventor Koujirou Yamashita

Koujirou Yamashita 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: 5294872
    Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.
    Type: Grant
    Filed: October 4, 1990
    Date of Patent: March 15, 1994
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Kazuo Tahara, Tsunehiro Endo, Kunio Miyashita, Yoshitaro Ishii, Fumio Jyoraku, Syuji Watanabe, Hisanori Toyoshima, Kohichi Saito, Wakichiro Hishi, Koujirou Yamashita
  • Patent number: 5166585
    Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.
    Type: Grant
    Filed: October 4, 1991
    Date of Patent: November 24, 1992
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Kazuo Tahara, Tsunehiro Endo, Kunio Miyashita, Yoshitaro Ishii, Fumio Jyoraku, Syuji Watanabe, Hisanori Toyoshima, Kohichi Saito, Wakichiro Hishi, Koujirou Yamashita
  • Patent number: 5075607
    Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.
    Type: Grant
    Filed: October 4, 1990
    Date of Patent: December 24, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Kazuo Tahara, Tsunehiro Endo, Kunio Miyashita, Yoshitaro Ishii, Fumio Jyoraku, Syuji Watanabe, Hisanori Toyoshima, Kohichi Saito, Wakichiro Hishi, Koujirou Yamashita
  • Patent number: 5050057
    Abstract: A power source apparatus has a power factor improving circuit which uses switching elements (4) as buildup transistors. According to the power source apparatus of the present invention, a current carrying ratio of the switching elements is decided to be a value which is obtained by subtracting a number of proportional value of the power source current waveform from the maximum current carrying ratio. Since the device of the present invention does not necessitate a detecting circuit of the power source voltage waveform for outputting an instruction waveform, the circuit thereof is simple and is not affected by the voltage change of the power source and noise generated at the power source.
    Type: Grant
    Filed: January 18, 1989
    Date of Patent: September 17, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Yasuo Notohara, Tsunehiro Endo, Koujirou Yamashita, Motoo Futami, Shigeru Kishi
  • Patent number: 4998034
    Abstract: A cylindrical field system of a low speed high torque motor is divided in an axial direction into first and second field system portions, these two field system portions are connected by a connecting member and a field magnet is disposed between the field system portions so that particularly machine work can be made before fitting of the field magnet. Accordingly, chips can be removed easily by use of a simple device.A cylindrical field system is divided in an axial direction into first and second field system portions, these field system portions are connected by a connecting member and cylindrical magnets fixed to a flexible belt-like fixture are wound on the field system portions between them so as to produce a rotor. Accordingly, the assembling property of the motor can be improved remarkably.
    Type: Grant
    Filed: September 28, 1989
    Date of Patent: March 5, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Ichiro Hashimoto, Giichi Ishida, Koujirou Yamashita
  • Patent number: 4983895
    Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaner surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.
    Type: Grant
    Filed: June 13, 1989
    Date of Patent: January 8, 1991
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Kazuo Tahara, Tsunehiro Endo, Kunio Miyashita, Yoshitaro Ishii, Fumio Jyoraku, Syuji Watanabe, Hisanori Toyoshima, Kohichi Saito, Wakichiro Hishi, Koujirou Yamashita
  • Patent number: 4880474
    Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: November 14, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Kazuo Tahara, Tsunehiro Endo, Kunio Miyashita, Yoshitaro Ishii, Fumio Jyoraku, Syuji Watanabe, Hisanori Toyoshima, Kohichi Saito, Wakichiro Hishi, Koujirou Yamashita
  • Patent number: 4855652
    Abstract: AC power supply is converted to DC by a rectifier circuit. The DC is stepped up by a step-up chopper circuit. The output of the step-up chopper circuit is smoothed by a smoothing circuit. The output of the smoothing circuit is input to an inverter via a current detecting circuit and a voltage detecting circuit. A synchronous motor is connected to the inverter. When the speed of the synchronous motor is judged to be in a high speed region based on the output signal of the voltage detecting circuit, the first speed control apparatus operates the interrupting control of the switching element of the step-up chopper circuit in such a manner that a deviation speed between an instruction speed signal to the motor and the detected speed of the motor reaches to zero.
    Type: Grant
    Filed: January 25, 1988
    Date of Patent: August 8, 1989
    Assignee: Hitachi, Ltd.
    Inventors: Koujirou Yamashita, Stunehiro Endo, Kunio Miyashita, Susumu Kashiwazaki, Kenichi Iizuka