We Claim:
[Claim 1]
A break detection device comprising:
a sensor having an output signal, the output signal varying when vibration is generated in a rope of an elevator;
detection means for detecting occurrence of an abnormal variation in the output signal from the sensor;
storage means for storing, when the detection means detects the occurrence of the abnormal variation, a position of a car of the elevator at the time of the occurrence of the variation in association with a determination score;
arithmetic means for increasing the determination score when the detection means detects the occurrence of the abnormal variation when the car passes the position stored in the storage means, and decreasing the determination score when the detection means does not detect the occurrence of the abnormal variation when the car passes the position; and
determination means for determining whether or not a broken portion is present in the rope on the basis of the determination score. [Claim 2]
The break detection device according to Claim 1, wherein
the detection means detects the occurrence of the abnormal variation when the variation of the output signal from the sensor exceeds a first threshold value. [Claim 3]
The break detection device according to Claim 1 or 2, wherein
the determination means determines that the broken portion is present in the rope when the determination score exceeds a second threshold value. [Claim 4]
The break detection device according to Claim 3, wherein
the arithmetic means adds a specific value to the determination score when the detection means detects the occurrence of the abnormal variation when the car passes the position, and
the second threshold value is a value greater than or equal to a sum of an initial value of the determination score and the specific value. [Claim 5]
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The break detection device according to any one of Claims 1 to 3, wherein
the arithmetic means subtracts a specific value from the determination score when the detection means does not detect the occurrence of the abnormal variation when the car passes the position, and
the specific value is a value greater than 0 and less than or equal to 1/2 of an initial value of the determination score. [Claim 6]
The break detection device according to Claim 1 or 2, wherein
the determination means determines that the broken portion is present in the rope when the determination score exceeds a second threshold value and, thereafter, the detection means detects the occurrence of the abnormal variation when the car with no passenger passes the position. [Claim 7]
The break detection device according to Claim 3, further comprising:
operation control means for causing the car to make a round trip in a section including the position stored in the storage means when the detection means detects the occurrence of the abnormal variation, wherein
the determination means determines that the broken portion is present in the rope when the determination score exceeds the second threshold value. [Claim 8]
The break detection device according to Claim 7, wherein
the operation control means causes the car to make a round trip in the section including the position until the determination score exceeds the second threshold value or the determination score becomes 0. [Claim 9]
A break detection device comprising:
a sensor having an output signal, the output signal varying when vibration is generated in a rope of an elevator;
detection means for detecting occurrence of an abnormal variation in the output signal from the sensor;
storage means for storing, when the detection means detects the occurrence of the abnormal variation, a position of a car of the elevator at the time of the occurrence of the
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variation; and
determination means for determining whether or not a broken portion is present in the rope on the basis of a frequency of the detection of the occurrence of the abnormal variation performed by the detection means when the car passes the position stored in the storage means. [Claim 10]
The break detection device according to Claim 9, wherein
the detection means detects the occurrence of the abnormal variation when the variation of the output signal from the sensor exceeds a first threshold value. [Claim 11]
The break detection device according to Claim 9 or 10, further comprising:
an arithmetic unit for calculating the frequency, wherein
the storage means stores, when the detection means detects the occurrence of the abnormal variation, the position of the car of the elevator at the time of the occurrence of the variation in association with a detection value,
the detection value is set to a positive value when the detection means detects the occurrence of the abnormal variation when the car passes the position stored in the storage means, and is set to 0 when the detection means does not detect the occurrence of the abnormal variation when the car passes the position,
the arithmetic unit calculates a moving average of the detection value as the frequency, and
the determination means determines whether or not the broken portion is present in the rope on the basis of the moving average calculated by the arithmetic unit. [Claim 12]
The break detection device according to any one of Claims 9 to 11, wherein
the determination means determines that the broken portion is present in the rope when the frequency exceeds a third threshold value. [Claim 13]
The break detection device according to any one of Claims 1 to 12, wherein
the detection means does not detect the occurrence of the abnormal variation in the output signal from the sensor during a time period immediately after the car starts to move. [Claim 14]
The break detection device according to Claim 2 or 10, wherein
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the detection means detects the occurrence of the abnormal variation when the
variation of the output signal from the sensor exceeds a fourth threshold value during a time
period immediately after the car starts to move, the fourth threshold value being a value greater
than the first threshold value.
[Claim 15]
The break detection device according to Claim 13 or 14, wherein
the time period immediately after the car starts to move is a time period from when the
car starts to move to when an acceleration of the car becomes constant.
[Claim 16]
The break detection device according to Claim 2 or 10, wherein
the detection means detects the occurrence of the abnormal variation when the
variation of the output signal from the sensor exceeds a fifth threshold value during a time
period immediately after the car starts to move and during a time period immediately before the
car stops, the fifth threshold value being a value greater than the first threshold value .
[Claim 17]
The break detection device according to Claim 16, wherein
each of the time period immediately after the car starts to move and the time period
immediately before the car stops is a time period in which a speed of the car is lower than a first
speed, and
the first speed is a speed at which a frequency band of a torque ripple of a traction
machine having a driving sheave around which the rope is wound deviates from a band of
characteristic frequencies that are generated by contact of the broken portion present in the rope
with a rope guide for the rope.
[Claim 18]
The break detection device according to any one of Claims 1 to 16, wherein the detection means extracts a signal component in a band of characteristic frequencies that are generated by contact of the broken portion present in the rope with a rope guide for the rope.
[Claim 19]
The break detection device according to any one of Claims 1 to 18, wherein the output signal from the sensor is a torque signal from a traction machine having a driving sheave around which the rope is wound, a load signal from a load weighing device that
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detects a load of the car, or an acceleration signal from an accelerometer that detects the acceleration of the car.
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