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Method and detection system for monitoring the speed of an elevator car

  • US 7,775,329 B2
  • Filed: 04/14/2006
  • Issued: 08/17/2010
  • Est. Priority Date: 04/21/2005
  • Status: Active Grant
First Claim
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1. A method of monitoring a speed of an elevator car, wherein movement of a drive pulley driving the elevator car and a counterweight is detected and evaluated and retardation of the elevator car is initiated in the case of an impermissible deviation of the speed of the elevator car from a speed preset, comprising the steps of:

  • a. performing a learning travel by moving and measuring a speed of the elevator car, wherein the speed of the elevator car measured during the learning travel is stored as a nominal speed of the elevator car;

    b. providing the elevator car at a stop at a floor;

    c. monitoring the drive pulley directly for movement of the elevator car and comparing the speed of the elevator car with a standstill speed to detect whether the elevator car leaves a standstill position, wherein the standstill speed is a fraction of the nominal speed of the elevator car, and the standstill position is an instantaneous position of the elevator car when the speed of the elevator car is less than the standstill speed; and

    d. in response to detecting that the elevator car has left the stop by determining that the elevator car has exceeded a specific deviation from the standstill position, activating a brake to stop the elevator car.

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