Method and detection system for monitoring the speed of an elevator car
First Claim
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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Accused Products
Abstract
A method and detection system monitors the speed of an elevator car and, in case of excess speed caused by brake failure of a motor brake or shaft fracture of a drive pulley shaft, a safety circuit is opened and the detection system is transferred from a normal operational state (State 1) to a retardation state (State 2) in which it is monitored whether the elevator car is retarded after defined speed presets. After a successful retardation, the detection system is transferred to a state of standstill monitoring (State 3) in which it is monitored whether the elevator car leaves its standstill position. If the presets of State 2 or State 3 are not fulfilled, the detection system is transferred to a braking state of the brake (State 4) in which a brake which fixes the elevator car is activated.
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Citations
11 Claims
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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:
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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. - View Dependent Claims (2, 3, 4)
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5. A detection system for monitoring a speed of an elevator car comprising:
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a measuring system for directly detecting and generating an output signal representative of a movement of a drive pulley driving the elevator car and a counterweight; and a computer for evaluating said output signal from said measuring system, wherein when the elevator car is provided at a stop at a floor, the computer monitors the output signal for movement of the elevator car and compares a 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 a nominal speed of the elevator car, wherein the nominal speed is determined by 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 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 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, the computer activates a brake to stop the elevator car. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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Specification