Patents Assigned to Schindler Elevator Corporation
  • Patent number: 4793442
    Abstract: A method and apparatus for providing pre-travel energy to an electrical elevator drive includes a load cell assembly for sensing the actual suspended weight of an elevator car and its passengers and a microprocessor which utilizes logic subroutines to manipulate this load data and data from a distance tachometer and car mounted sensors. The subroutines include an initializing subroutine which determines the empty car weight and balancing torques at the limits of travel, a normalizing subroutine which normalizes this data and determines the actual weight of the car and passengers and a rope compensation subroutine which calculates the torque required to balance the weight of the cables suspended from the elevator car. From the foregoing data, the microprocessor provides a pre-travel electrical signal to the elevator drive which corresponds to the torque level required to maintain the elevator car stationary during the interval between release of the brake and application of drive pattern power.
    Type: Grant
    Filed: November 5, 1987
    Date of Patent: December 27, 1988
    Assignee: Schindler Elevator Corporation
    Inventors: Mark K. Heckler, Larry V. Birney