Patents by Inventor Hirofumi Sugiura

Hirofumi Sugiura 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).

  • Brake control system in elevator control apparatus
    Patent number: 5247140
    Abstract: The current an inverter is used as a power source for a brake circuit. The brake circuit includes a current detector, a comparator for comparing the detected value with a dictated brake current pattern, and a switch which switches the brake current in accordance with the magnitude of the difference between the detected current value and the dictated value. The brake current is selected to smoothly increase and decrease the brake current to prevent vibration and noise.
    Type: Grant
    Filed: August 7, 1991
    Date of Patent: September 21, 1993
    Assignee: Otis Elevator Company
    Inventors: Masao Iwasa, Koji Yamada, Hirofumi Sugiura
  • Offset correction circuit of PWM inverter
    Patent number: 5105352
    Abstract: The DC offset in a current control system for a PWM inverter drive is corrected by integrating a DC component of a current control signal provided by a current control amplifier and feedback controlling the current control amplifier to reduce the DC component to zero.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: April 14, 1992
    Assignee: Otis Elevator Company
    Inventors: Masao Iwasa, Hirofumi Sugiura