TITLE: BREAK DETECTING DEVICE
FIELD [0001]
The present invention relates to a device for detecting a break in a wire or a break in a strand that have occurred in a rope.
BACKGROUND
[0002]
Various ropes are used in an elevator device. For example, an elevator car is suspended in a shaft by a main rope. The main rope is wound around pulleys such as a driving sheave of a traction machine. Since the main rope is repeatedly bent by movements of the car, the main rope gradually deteriorates. As the main rope deteriorates, wires constituting the main rope break. When enough wires break, a strand formed by twisting wires together may break. In addition, a break of a wire or a break of a strand may also occur when a foreign object becomes lodged between the main rope and a pulley. [0003]
A broken wire or strand protrudes from a surface of the main rope. Therefore, when an operation of the elevator is performed in a state where a wire or a strand is broken, the broken wire or strand comes into contact with devices provided in the shaft. [0004]
Elevator devices are described in PTL 1 and PTL 2. In the elevator device described in PTL 1, a driving sheave of a traction machine is provided with a rope guide. In addition, a vibration of the rope guide is detected by a sensor. An occurrence of a break of a wire or a strand is detected on the basis of a vibration detected by the sensor. [0005]
In the elevator device described in PTL 2, a car is provided with an accelerometer. An occurrence of a break of a wire or a strand is detected on the basis of acceleration detected by the accelerometer. Citation List

Patent Literature
[0006]
[PTL1]JP 5203339 B
[PTL 2] JP HI0-81462 A
SUMMARY
Technical Problem
[0007]
In an elevator device, a range of a main rope which passes through each pulley is determined in advance. For example, a portion in a certain range of the main rope passes through a driving sheave. The portion passing through the driving sheave does not necessarily pass through a suspension sheave of a counterweight. Therefore, detecting a break of a wire or a break of a strand using the sensor described in PTL 1 requires that the sensor be attached to a position of each pulley around which the main rope is wound. For example, when the sensor is attached to a position of a suspension sheave of a counterweight, a signal line must be installed between the counterweight and a controller. There is a problem in that a large number of sensors are required and a signal line must be led out from each sensor, resulting in a complicated configuration. Such a problem becomes prominent particularly in an elevator device adopting a 2:1 roping system which uses a large number of pulleys. [0008]
In the elevator device described in PTL 2, a break of a wire or a break of a strand is detected from sudden change of acceleration detected by the accelerometer. However, occurrences of a break of a wire or a break of a strand are not the only times the accelerometer detects sudden change of acceleration. For example, when oil applied to rails is depleted, a car swings slightly every time the car passes a joint of the rails. With the elevator device described in PTL 2, such a phenomenon may also be detected as a break of a wire or a break of a strand. [0009]
The present invention is made in order to solve the problems described above. An object of the present invention is to provide a break detecting device capable of accurately detecting an occurrence of a break of a wire or a strand with a simple configuration.
Solution to Problem

[0010]
A break detecting device of the present invention comprises a sensor of which an output signal varies when a vibration is generated in a rope of an elevator, storage means configured to store a variation in the output signal from the sensor in association with a position of a car of the elevator, and break determination means configured to determine, on the basis of the position of the car and a transition of the variation in the output signal from the sensor, whether or not a broken portion is present in the rope. [0011]
A break detecting device of the present invention comprises a sensor of which an output signal varies when a vibration is generated in a rope of an elevator, storage means configured to store a variation in the output signal from the sensor in association with a position of a car of the elevator, and break determination means configured to determine, on the basis of a reproducibility of the position of the car at a moment the variation in the output signal from the sensor exceeds a first threshold and a reproducibility of the position of the car at a moment the variation in the output signal from the sensor exceeds a second threshold that is larger than the first threshold, whether or not a broken portion is present in the rope.
Advantageous Effects of Invention [0012]
The break detecting device according to the present invention includes a sensor, storage means, and break determination means. An output signal of the sensor varies when a vibration is generated in a rope. A variation in the output signal from the sensor is stored in the storage means in association with a position of a car. The break determination means determines whether or not a broken portion is present in the rope on the basis of contents stored in the storage means. The break detecting device according to the present invention is capable of accurately detecting an occurrence of a break of a wire or a strand with a simple configuration.
BRIEF DESCRIPTION of DRAWINGS [0013]
Fig. 1 is a diagram schematically showing an elevator device.
Fig. 2 is a perspective view showing a return pulley.

Fig. 3 is a diagram showing a cross section of the return pulley.
Fig. 4 is a diagram for illustrating how a broken portion of a main rope moves.
Fig. 5 is a diagram for illustrating how the broken portion of the main rope moves.
Fig. 6 is a diagram for illustrating how the broken portion of the main rope moves.
Fig. 7 is a diagram showing outputs of sensor signals.
Fig. 8 is a diagram showing outputs of sensor signals.
Fig. 9 is a diagram showing an example of a break detecting device according to a first embodiment of the present invention.
Fig. 10 is a flow chart showing an operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 11 is a flow chart showing a detailed operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 12 is a flow chart showing a detailed operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 13 is a diagram showing a state where the broken portion is in contact with a rope guide.
Fig. 14 is a diagram for illustrating an example of functions of an abnormal variation detection unit.
Fig. 15 is a diagram for illustrating an example of functions of a reproducibility determination unit.
Fig. 16 is a diagram for illustrating an example of functions of the reproducibility determination unit.
Fig. 17 is a diagram schematically showing an elevator device.
Fig. 18 is a diagram showing outputs of sensor signals.
Fig. 19 is a diagram showing a transition of an amplitude of a variation having occurred in a sensor signal.
Fig. 20 is a diagram showing a transition of an amplitude of a variation having occurred in a sensor signal.
Fig. 21 is a diagram which combines and three-dimensionally shows Figs. 19 and 20.
Fig. 22 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 23 is a diagram showing a transition of an amplitude of a variation having occurred

in a sensor signal.
Fig. 24 is a diagram showing a transition of an amplitude of a variation having occurred in a sensor signal.
Fig. 25 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 26 is a diagram showing a transition of an amplitude of a variation having occurred in a sensor signal.
Fig. 27 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 28 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention.
Fig. 29 is a flow chart showing an operation example of the break detecting device according to a second embodiment of the present invention.
Fig. 30. is a diagram for illustrating an example of functions of the abnormal variation detection unit.
Fig. 31 is a diagram for illustrating an advantage of using a plurality of sensor signals.
Fig. 32 is a diagram showing a hardware configuration of a controller.
DESCRIPTION of EMBODIMENTS [0014]
The present invention will be described with reference to the accompanying drawings. Redundant descriptions will be simplified or omitted as appropriate. In each of the drawings, the same reference signs indicate the same or corresponding parts. [0015] First Embodiment
Fig. 1 is a diagram schematically showing an elevator device. A car 1 moves up and down in a shaft 2. The shaft 2 is, for example, a space extending upward and downward which is formed inside a building. A counterweight 3 moves up and down in the shaft 2. The car 1 and the counterweight 3 are suspended in the shaft 2 by a main rope 4. A roping system for suspending the car 1 and the counterweight 3 is not limited to an example shown in Fig. 1. For example, the car 1 and the counterweight 3 may be suspended in the shaft 2 by 1:1 roping. Hereinafter, an example in which the car 1 and the counterweight 3 are suspended by 2:1 roping

will be described in detail. [0016]
One end portion 4a of the main rope 4 is supported by a stationary body in the shaft 2. The end portion 4a is an end portion that is closer to the car 1 in the end portions of the main rope 4. For example, the end portion 4a of the main rope 4 is supported by a stationary body provided at the top of the shaft 2. The main rope 4 extends downward from the end portion 4a. From a side of the end portion 4a, the main rope 4 is sequentially wound around a suspension sheave 5, a suspension sheave 6, a return pulley 7, a driving sheave 8, a return pulley 9, and a suspension sheave 10. The main rope 4 extends upward from a portion wound around the suspension sheave 10. The other end portion 4b of the main rope 4 is supported by a stationary body in the shaft 2. The end portion 4b is an end portion that is closer to the counterweight 3 in the end portions of the main rope 4. For example, the end portion 4b of the main rope 4 is supported by a stationary body provided at the top of the shaft 2. [0017]
The suspension sheave 5 and the suspension sheave 6 are included in the car 1. The suspension sheave 5 and the suspension sheave 6 are provided on, for example, a lower part of a car floor. The suspension sheave 5 and the suspension sheave 6 are rotatable relative to the car floor. The return pulley 7 and the return pulley 9 are provided on, for example, a stationary body at the top of the shaft 2. The return pulley 7 and the return pulley 9 are rotatable relative to the stationary body at the top of the shaft 2. The driving sheave 8 is included in a traction machine 11. The traction machine 11 is provided in, for example, a pit of the shaft 2. The suspension sheave 10 is included in the counterweight 3. The suspension sheave 10 is provided on, for example, an upper part of a frame supporting a weight. The suspension sheave 10 is rotatable relative to the frame. [0018]
An arrangement of the sheaves and pulleys around which the main rope 4 is wound is not limited to the example shown in Fig. 1. For example, the driving sheave 8 may be arranged in a machine room (not shown) at the top of the shaft 2 or above the shaft 2. [0019]
A load weighing device 12 detects a load of the car 1. The load weighing device 12 detects a load of the car 1 on the basis of, for example, a load applied to the end portion 4a of the main rope 4. The load weighing device 12 outputs a load signal in accordance with a

detected load. The load signal output from the load weighing device 12 is input to a controller
13.
[0020]
The traction machine 11 has a torque-detecting function. The traction machine 11 outputs a torque signal in accordance with a detected torque. The torque signal output from the traction machine 11 is input to the controller 13. [0021]
A governor 15 operates a safety gear (not shown) when a speed of descent of the car 1 exceeds a reference speed. The safety gear is included in the car 1. When the safety gear is operated, the car 1 is forcibly stopped. For example, the governor 15 includes a governor rope 16, a governor sheave 17, and an encoder 18. The governor rope 16 is wound around the governor sheave 17. When the car 1 moves, the governor rope 16 moves. When the governor rope 16 moves, the governor sheave 17 rotates. The encoder 18 outputs a rotation signal in accordance with a direction of rotation and a rotational angle of the governor sheave 17. The rotation signal output from the encoder 18 or, in other words, an encoder signal from the governor 15 is input to the controller 13. The encoder 18 is an example of a sensor which outputs a signal in accordance with a position of the car 1. [0022]
Fig. 2 is a perspective view showing the return pulley 9. Fig. 3 is a diagram showing a cross section of the return pulley 9. A rope guide 19 is provided on a member supporting the return pulley 9. Figs. 2 and 3 show an example in which the rope guide 19 is provided on a shaft 9a of the return pulley 9. The rope guide 19 prevents the main rope 4 from being dislocated from a groove of the return pulley 9. For example, the rope guide 19 opposes, across a gap, a portion wound around the groove of the return pulley 9 in the main rope 4. The main rope 4 does not come into contact with the rope guide 19 unless an abnormality occurs in the main rope 4. [0023]
Figs. 2 and 3 show an example in which a broken portion 4c protrudes from a surface of the main rope 4. The broken portion 4c is a portion in which a wire constituting the main rope 4 has broken. The broken portion 4c may be a portion in which a strand formed by twisting wires together has broken. When the car 1 moves, the broken portion 4c comes into contact with the rope guide 19 when passing through the return pulley 9.

[0024]
Figs. 2 and 3 show the return pulley 9 as an example of a sheave or a pulley around which the main rope 4 is wound. A rope guide with a similar function to that of the rope guide 19 may be provided on the suspension sheave 5, the suspension sheave 6, the return pulley 7, the driving sheave 8, and the suspension sheave 10. [0025]
Figs. 4 to 6 are diagrams for illustrating how the broken portion 4c of the main rope 4 moves. Fig. 4 shows a state where the car 1 is stopped at a hall of a bottom floor. In the example shown in Fig. 4, the broken portion 4c is present between the end portion 4a and a portion wound around the suspension sheave 5 in the main rope 4. [0026]
Fig. 6 shows a state where the car 1 is stopped at a hall of a top floor. In the example shown in Fig. 6, the broken portion 4c is present between a portion wound around the return pulley 7 and a portion wound around the driving sheave 8 in the main rope 4. In other words, when the car 1 moves from the hall of the bottom floor to the hall of the top floor, the broken portion 4c sequentially passes through the suspension sheave 5, the suspension sheave 6, and the return pulley 7. Even when the car 1 moves from the hall of the bottom floor to the hall of the top floor, the broken portion 4c does not pass through the driving sheave 8, the return pulley 9, and the suspension sheave 10. In other words, the broken portion 4c does not necessarily pass through all of the sheaves and pulleys. A combination of sheaves and/or pulleys through which the broken portion 4c passes is determined by a position of occurrence of the broken portion 4c and the like. [0027]
Fig. 5 shows a state midway through a movement of the car 1 from the hall of the bottom floor to the hall of the top floor. Specifically, Fig. 5 shows a state where the broken portion 4c is passing through the suspension sheave 5. The broken portion 4c comes into contact with a rope guide provided on the suspension sheave 5 when passing through the suspension sheave 5. [0028]
Figs. 7 and 8 are diagrams showing outputs of sensor signals. Figs. 7(a) and 8(a) show a position of the car 1. In the example described in the present embodiment, a position of the car 1 is synonymous with a height at which the car 1 is present. Figs. 7(a) and 8(a) show

a variation in car position when the car 1 moves from the bottom floor (position 0) to a position P and then returns to the bottom floor. Waveforms shown in Figs. 7(a) and 8(a) are acquired on the basis of, for example, a rotation signal from the encoder 18. [0029]
Figs. 7(b) and 8(b) show a torque of the traction machine 11. Waveforms shown in Figs. 7(b) and 8(b) are, for example, waveforms of a torque signal output from the traction machine 11. Figs. 7(b) and 8(b) show an example in which a movement of the car 1 between the bottom floor and the position P has a maximum torque of Tqi and a minimum torque of-Tq2. Figs. 7(c) and 8(c) show a load of the car 1. Waveforms shown in Figs. 7(c) and 8(c) are, for example, waveforms of a load signal output from the load weighing device 12. Figs. 7(c) and 8(c) show an example in which the load of the car 1 is w [kg]. [0030]
Fig. 7 shows an example of waveforms that are obtained in a case where the broken portion 4c is not present in the main rope 4. Fig. 8 shows an example of waveforms that are obtained in a case where the broken portion 4c is present in the main rope 4 and the broken portion 4c passes through a certain pulley when the car 1 passes a position Pi. The broken portion 4c comes into contact with a rope guide when passing through the pulley. Accordingly, a vibration is generated in the main rope 4 when the broken portion 4c passes through the pulley. A displacement of the end portion 4a of the main rope 4 affects the load signal output from the load weighing device 12. When a vibration is generated in the main rope 4 and the generated vibration reaches the end portion 4a of the main rope 4, a variation occurs in the load signal from the load weighing device 12. In a similar manner, a displacement of a portion wound around the driving sheave 8 in the main rope 4 affects the torque signal output from the traction machine 11. When a vibration is generated in the main rope 4 and the generated vibration reaches the portion wound around the driving sheave 8 in the main rope 4, a variation occurs in the torque signal from the traction machine 11. [0031]
Fig. 9 is a diagram showing an example of a break detecting device according to the first embodiment of the present invention. Fig. 10 is a flow chart showing an operation example of the break detecting device according to the first embodiment of the present
hi
invention. The controller 13 includes, for example, a storage unit 20, a car position detection unit 21, an abnormal variation detection unit 22, a reproducibility determination unit 23, a break

determination unit 24, an operation control unit 25, and a notification unit 26. [0032]
Hereinafter, functions and operations of the break detecting device will be described in detail also with reference to Figs. 11 to 21. Figs. 11 and 12 are flow charts showing a detailed operation example of the break detecting device according to the first embodiment of the present invention. Fig. 12 shows a flow of operations that follows Fig. 11. In other words, Figs. 11 and 12 show a flow of a series of operations. [0033]
The abnormal variation detection unit 22 detects a variation in a sensor signal (S101). In the example described in the present embodiment, for example, a load signal and a torque signal can be adopted as the sensor signal. In addition, in an example other than that described in the present embodiment, for example, an acceleration signal from an accelerometer (not shown) provided in the car 1 can be adopted as the sensor signal. In other words, when a vibration is generated in the main rope 4, an acceleration signal varies in a similar to a load signal and a torque signal. Hereinafter, an example in which a torque signal is adopted as the sensor signal will be described in detail. In S101, the abnormal variation detection unit 22 detects a variation that has occurred in the torque signal. [0034]
Fig. 13 is a diagram showing a state where the broken portion 4c is in contact with the rope guide 19. When the car 1 moves and reaches a certain position, the broken portion 4c comes into contact with the rope guide 19 as shown in Fig. 13. After coming into contact with the rope guide 19, the broken portion 4c deforms while rubbing against the rope guide 19 with a movement of the main rope 4. Subsequently, the broken portion 4c detaches from the rope guide 19. [0035]
The contact between the broken portion 4c and the rope guide 19 acts as a forcible disturbance with respect to the elevator. For example, when the broken portion 4c comes into contact with the rope guide 19, an abnormal variation appears in the torque signal from the traction machine 11. This abnormal variation has a component in a unique frequency band in accordance with a length of the broken portion 4c and a speed of movement of the main rope 4. If the broken portion 4c has a length of d [m] and the speed of movement of the main rope 4 is v [m/s], then a frequency f [Hz] of the abnormal variation (vibration) can be expressed by the

following equation.
f=v/d...(l) [0036]
Fig. 14 is a diagram for illustrating an example of functions of the abnormal variation detection unit 22. The abnormal variation detection unit 22 includes, for example, a band-pass filter 27, an amplifier 28, and a determiner 29. For the sake of brevity, the band-pass filter will also be described as a BPF in the drawings and the like. As described above, when the broken portion 4c comes into contact with the rope guide 19, an abnormal variation appears in the torque signal from the traction machine 11. However, this variation may have a small amplitude. Therefore, in the example described in the present embodiment, the abnormal variation detection unit 22 includes the amplifier 28 for amplifying a signal. [0037]
The abnormal variation detection unit 22 first performs a filtering process to an input torque signal (Sill). For example, the band-pass filter 27 extracts a signal component in a band of characteristic frequency. The signal component in a band of characteristic frequency is a signal component created as a result of the broken portion 4c present in the main rope 4 coming into contact with a rope guide for the main rope 4. The characteristic frequency includes the frequency f calculated by the equation (1) given above. Moreover, the length d is a value set as a length of the broken portion 4c that occurs in the main rope 4. For example, when a strand corresponding to 0.5 to several pitches becomes untwisted, the length of the broken portion 4c is set to a length of the untwisted strand. The speed v of movement of the main rope 4 is determined in accordance with the speed of movement of the car 1. For example, the speed v of movement of the main rope 4 can be calculated from a rated speed of the car 1. [0038]
The amplifier 28 squares an output signal u from the band-pass filter 27 to amplify the signal. In the present embodiment, an extracted and amplified signal component in the band of characteristic frequency will be referred to as a band-pass filter output or a filter output. In other words, in the example described in the present embodiment, an output signal Y (= u2) from the amplifier 28 is the band-pass filter output. In the example described in the present embodiment, a sign of the band-pass filter output is positive. When the abnormal variation detection unit 22 does not include the amplifier 28, the output signal u from the band-pass filter

27 is the band-pass filter output. [0039]
The abnormal variation detection unit 22 shown in Fig. 14 is an example. The abnormal variation detection unit 22 may include a non-linear filter for extracting a signal component in the band of characteristic frequency. An adaptive filter algorithm may be applied to the abnormal variation detection unit 22 to extract a signal component in the band of characteristic frequency. [0040]
The determiner 29 determines whether or not a variation in the torque signal or, in other words, the output signal Y from the amplifier 28 exceeds a threshold TH1 (SI 12). The threshold TH1 that is compared with the output signal Y is stored in advance in, for example, the storage unit 20. When the determiner 29 determines that the output signal Y has not exceeded the threshold TH1, the operation control unit 25 controls a normal operation (SI27). [0041]
The car position detection unit 21 detects a position of the car 1. The car position detection unit 21 detects a position of the car 1 on the basis of, for example, a rotation signal output from the encoder 18. Moreover, a method by which the car position detection unit 21 detects a position is not limited to the example described in the present embodiment. For example, the traction machine 11 includes an encoder. The encoder included in the traction machine 11 is also an example of a sensor which outputs a signal in accordance with a position of the car 1. The car position detection unit 21 may detect a position of the car 1 on the basis of an encoder signal from the traction machine 11. Alternatively, the governor 15 may have a function for detecting a position of the car 1. The traction machine 11 may have a function for detecting a position of the car 1. In this case, a signal indicating a position of the car 1 is input to the controller 13. [0042]
When it is determined in SI 12 that the output signal Y exceeds the threshold TH1, the car position detection unit 21 detects a position of the car 1 (SI 13). [0043]
When the output signal Y obtained in SI 11 exceeds the threshold TH1, the abnormal variation detection unit 22 causes the output signal Y obtained in SI 11 and a position P of the car 1 at the moment the output signal Y is obtained to be stored in the storage unit 20 (SI 14).

The output signal Y from the amplifier 28 and the position P detected by the car position detection unit 21 are associated with each other and stored in the storage unit 20. Moreover, in each example described in the present embodiment, not only a part of the output signals Y but all output signals Y are desirably also stored in the storage unit 20 in association with a car position. [0044]
Next, the abnormal variation detection unit 22 determines whether or not the detection of the output signal Y exceeding the threshold TH1 has been made more than once (SI 15). When the detection of the output signal Y exceeding the threshold TH1 is not a second or subsequent detection, the abnormal variation detection unit 22 detects that an abnormal variation has occurred for the first time (S116). In this case, the operation control unit 25 controls a normal operation (SI27). [0045]
Next, the reproducibility determination unit 23 determines a reproducibility of the variation having occurred in the sensor signal (SI02). [0046]
Fig. 15 is a diagram for illustrating an example of functions of the reproducibility determination unit 23. Fig. 15(a) shows a position of the car 1. In the example shown in Fig. 15, the car 1 passes a position Pi at a time ti, a time ti, a time t3, and a time U. Fig. 15(b) shows a torque of the traction machine 11. Fig. 15(c) shows a band-pass filter output. When the broken portion 4c is present in the main rope 4, the broken portion 4c comes into contact with a rope guide as the car 1 passes a certain position. Fig. 15 shows an example in which the broken portion 4c comes into contact with a rope guide when the car 1 passes the position Pi. [0047]
When the broken portion 4c is present in the main rope 4, a car position at the moment the broken portion 4c comes into contact with a certain rope guide is the same. Therefore, when the broken portion 4c is present in the main rope 4, the same car position is stored in the storage unit 20 every time the car 1 passes a position where the broken portion 4c comes into contact with the rope guide. In the example shown in Fig. 15, the position Pi is stored in the storage unit 20 at the time ti, the time t2, the time t3, and the time U- Therefore, when a car position at the moment the output signal Y exceeding the threshold TH1 is detected is reproducible, it is likely that the broken portion 4c is present in the main rope 4.

[0048]
When it is determined in SI 15 that the detection of the output signal Y exceeding the threshold TH1 is a second or subsequent detection, the reproducibility determination unit 23 determines whether or not the car position at the moment the output signal Y exceeds the threshold TH1 is reproducible (S117). The reproducibility determination unit 23 determines in SI 17 that there is reproducibility when, for example, a plurality of positions P stored in the storage unit 20 can be considered a same position. For example, when a plurality of positions P stored in the storage unit 20 are present within a certain range, the positions P can be considered a same position. The certain range described above is set in advance in consideration of, for example, an accuracy of detecting a car position or the like. In the example shown in Fig. 15, the reproducibility determination unit 23 determines that there is reproducibility at the position Pi. [0049]
When the reproducibility determination unit 23 determines in SI 17 that there is reproducibility, the reproducibility determination unit 23 causes the number of times the output signal Y has exceeded the threshold TH1 at the position or, in other words, a position that can be considered the same to be stored in the storage unit 20 (SI 18). In the example shown in Fig. 15, the fact that the threshold TH1 has been exceeded twice at the position Pi at the time t2 is stored in the storage unit 20. [0050]
When the reproducibility determination unit 23 determines in SI 17 that there is no reproducibility, the reproducibility determination unit 23 determines that the detection of the output signal Y exceeding the threshold TH1 is attributable to a variation randomly created in the torque signal (SI 19). In this case, the operation control unit 25 controls a normal operation (S127). [0051]
The reproducibility determination unit 23 may determine that there is reproducibility when, in SI 17, the output signal Y consecutively exceeds the threshold TH1 a plurality of times as the car 1 passes a position that can be considered the same. [0052]
Fig. 16 is a diagram for illustrating an example of functions of the reproducibility determination unit 23. Fig. 16(a) shows a latest band-pass filter output obtained when the car

1 travels a section from a position 0 to a position P. In the example shown in Fig. 16(a), the output signal Y from the amplifier 28 exceeds the threshold TH1 at a position Pi and a position P2. Fig. 16(b) shows a band-pass filter output of an immediately previous travel obtained when the car 1 had traveled the same section. In the example shown in Fig. 16(b), the output signal Y exceeds the threshold TH1 at the position Pi, the position P2, and a position P3. [0053]
For example, let us consider a case where a determination that there is reproducibility is made in SI 17 when the output signal Y twice consecutively exceeds the threshold TH1 as the car 1 passes a position that can be considered the same. At the position Pi and the position P2, the output signal Y twice consecutively exceeds the threshold TH1. In this case, the reproducibility determination unit 23 determines that there is reproducibility at the position Pi and the position P2. On the other hand, the output signal Y does not exceed the threshold TH1 at the position P3 in Fig. 16(a). In this case, the reproducibility determination unit 23 does not determine that there is reproducibility at the position P3. An occurrence of the variation at the position P3 shown in Fig. 16(b) is determined to be attributable to a non-reproducible phenomenon such as a passenger jumping inside the car 1. [0054]
Next, the break determination unit 24 determines a presence or absence of the broken portion 4c (S103). [0055]
Fig. 17 is a diagram schematically showing an elevator device. In Fig. 17, the controller 13 and the governor 15 have been omitted. A movement of the car 1 is guided by a guide rail provided in the shaft 2. The guide rail includes a large number of rails 30. The guide rail is arranged over a range of movement of the car 1 by having a plurality of rails 30 connected to one another in a vertical direction. Therefore, there is a joint between one rail 30 and a rail 30 arranged directly above or directly below the one rail 30. [0056]
When oil applied to the rails 30 is depleted, the car 1 swings slightly when the car 1 passes a joint between the rails 30. Since the main rope 4 is wound around the suspension sheave 5 and the suspension sheave 6, a vibration is generated in the main rope 4 when the car 1 swings. Therefore, a variation may occur in the sensor signal when the car 1 passes a joint of the rails 30. A variation may also occur in the sensor signal when a joint of the rails 30 is

uneven. [0057]
Fig. 18 is a diagram showing outputs of the sensor signals. Fig. 18 shows an example in which the car 1 passes a joint of the rails 30 at a position P4 and a variation occurs in the sensor signals. When a variation occurs in the sensor signals as the car 1 passes a joint of the rails 30, a car position at the time of occurrence of the variation is the same. In the example shown in Fig. 18, a variation occurs in the sensor signals every time the car 1 passes the position P4. A variation in the sensor signals attributable to a joint of the rails 30 is similar to a variation in the sensor signals attributable to the broken portion 4c in that a car position at the time of occurrence of the variation is reproducible. In the present embodiment, an example will be described in which variations having occurred in the sensor signal are differentiated between those attributable to the broken portion 4c and those attributable to a joint of the rails 30. [0058]
Figs. 19 and 20 are diagrams showing a transition of an amplitude of a variation having occurred in a sensor signal. In Figs. 19 and 20, ordinates represent band-pass filter output that is a value corresponding to an amplitude of the variation having occurred in the sensor signal. Abscissas represent the number of times the elevator is started. Alternatively, the abscissas in Figs. 19 and 20 may represent, for example, an elapsed time since installation of the elevator. [0059]
Fig. 19 shows a transition of the output signal Y obtained when the car 1 passes the position Pi. When the elevator is started for the Ml-th time, the broken portion 4c has not occurred in the main rope 4. Fig. 19 shows an example in which the broken portion 4c occurs in the main rope 4 when the elevator is started for the M2-th time. A break in a wire and a break in a strand occur suddenly. Therefore, a variation in the sensor signal attributable to the broken portion 4c occurs suddenly. When the broken portion 4c occurs in the main rope 4, a value of the output signal Y suddenly increases in comparison to an immediately previous value. In addition, after the broken portion 4c occurs in the main rope 4, the output signal Y consecutively indicates a large value as shown in Fig. 19. [0060]
Fig. 20 shows a transition of the output signal Y obtained when the car 1 passes the

position P4. An amount of oil applied to the rails 30 does not suddenly change. The amount of oil applied to the rails 30 gradually decreases and eventually becomes depleted unless oil is replenished. Therefore, a variation in the sensor signal attributable to a joint of the rails 30 gradually increases over time. Fig. 21 is a diagram which combines and three-dimensionally shows Figs. 19 and 20. In the present embodiment, an example will be described in which the break determination unit 24 detects a presence of the broken portion 4c on the basis of a position of the car 1 and a transition of a variation in the sensor signal from contents stored in the storage unit 20. [0061]
When the number of times the threshold TH1 is exceeded is stored in the storage unit 20 in SI 18, the break determination unit 24 determines whether or not the output signal Y obtained in S111 exceeds a threshold TH2 (S120). The threshold TH2 that is compared with the output signal Y is a value larger than the threshold TH1. The threshold TH2 is stored in advance in, for example, the storage unit 20. When the output signal Y does not exceed the threshold TH2, the break determination unit 24 determines that the detection of the output signal Y exceeding the threshold TH1 is attributable to a slight variation having occurred in the torque signal (S121). The slight variation occurs due to, for example, the car 1 passing a joint of the rails 30. In this case, the operation control unit 25 controls a normal operation (S127). [0062]
When the output signal Y exceeds the threshold TH2, the break determination unit 24 causes the number of times the output signal Y had exceeded the threshold TH2 at the same position to be stored in the storage unit 20 (SI22). Next, the break determination unit 24 determines whether or not the number of times the threshold TH2 is exceeded which is stored in the storage unit 20 in S122 is a plurality of times (S123). When the break determination unit 24 determines in SI 23 that the number of times the threshold TH2 is exceeded is a plurality of times, the break determination unit 24 determines that the broken portion 4c has occurred in the main rope 4 (SI24). In this case, the operation control unit 25 stops the car 1 at a nearest floor. In addition, the notification unit 26 notifies a management company of the elevator (S125). [0063]
When the break determination unit 24 determines in SI 23 that the number of times the threshold TH2 is exceeded is not a plurality of times, since the threshold TH2 is exceeded for the first time, the break determination unit 24 suspends determination on the presence or

absence of the broken portion 4c (SI 26). In this case, the operation control unit 25 controls a
normal operation (S127).
[0064]
In SI23, the break determination unit 24 may determine whether or not the number of times the threshold TH2 is exceeded has reached a prescribed number of times. In this case, when the number of times the threshold TH2 is exceeded has reached the prescribed number of times, the break determination unit 24 determines that the broken portion 4c has occurred in the main rope 4 (SI 24). On the other hand, when the number of times the threshold TH2 is exceeded has not reached the prescribed number of times, the break determination unit 24 suspends determination on the presence or absence of the broken portion 4c (SI 26). The prescribed number of times is set to, for example, three or more times. [0065]
In the break detecting device described in the present embodiment, the presence of the broken portion 4c is detected using a sensor of which an output signal varies when a vibration is generated in the main rope 4. As the sensor signal, for example, a torque signal or a load signal can be used. Therefore, with the break detecting device described in the present embodiment, a dedicated sensor need not be provided for determining the presence or absence of the broken portion 4c. In addition, the presence of the broken portion 4c can be detected as long as there is at least one sensor. A large number of sensors need not be provided for determining the presence or absence of the broken portion 4c. Therefore, a configuration can be simplified. [0066]
In the break detecting device described in the present embodiment, the break determination unit 24 determines the presence or absence of the broken portion 4c on the basis of a position of the car 1 and a transition of a variation in the sensor signal. With the break detecting device described in the present embodiment, a variation having occurred in the sensor signal can be differentiated as to whether the variation is attributable to the broken portion 4c or the variation is attributable to a joint of the rails 30. Therefore, detection accuracy of the broken portion 4c improves. [0067]
Specifically, in the example described above, the break determination unit 24 determines the presence or absence of the broken portion 4c on the basis of a reproducibility of

a car position at the moment the variation in the sensor signal exceeds the threshold TH1 and a reproducibility of a car position at the moment the variation exceeds the threshold TH2. As shown in Fig. 24, a variation in the sensor signal attributable to a joint of the rails 30 gradually increases over time. Therefore, the break determination unit 24 does not determine that the broken portion 4c is present in the main rope 4 when the variation in the sensor signal does not exceed the threshold TH2 even if a car position at the moment the variation in the sensor signal exceeds the threshold TH1 is reproducible. The break determination unit 24 determines that, for example, the variation is attributable to passing a joint of the rails 30. By adopting the two thresholds TH1 and TH2, a variation having occurred in the sensor signal can be differentiated as to whether the variation is attributable to the broken portion 4c or the variation is attributable to a joint of the rails 30. [0068]
The thresholds TH1 and TH2 may be set by performing a learning operation. In this case, for example, the controller 13 includes a threshold setting unit (not shown). The threshold setting unit sets the thresholds TH1 and TH2 on the basis of, for example, a variation in the sensor signal during the learning operation. [0069]
For example, the learning operation is performed upon completion of installation of the elevator. In the learning operation, for example, the car 1 is moved from the bottom floor to the top floor. In addition, a torque signal acquired at that time is subjected to a filtering process. For example, the threshold setting unit sets a constant multiple of a maximum value of the variation in the sensor signal acquired by the learning operation as the threshold TH1, and sets a value larger than the constant multiple as the threshold TH2. The threshold setting unit may set a constant multiple of a maximum value of the variation in the sensor signal as the threshold TH2 and set a value smaller than the constant multiple as the threshold TH1. [0070]
The torque signal from the traction machine 11 varies after installation of the elevator due to secular change. Therefore, the thresholds TH1 and TH2 may be regularly updated. Updates of the thresholds TH1 and TH2 are desirably performed at short intervals. For example, in consideration of an operational state of the elevator, the learning operation is carried out during a time slot with a small number of users such as night time. Performing the learning operation at a same speed as a speed of a normal operation for transporting users to

destination floors enables an occurrence of the broken portion 4c to be detected during a normal operation. The need for regular inspections by an elevator maintenance person can be eliminated. [0071]
Fig. 22 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention. Fig. 22 shows a flow of operations that follows Fig. 11. In other words, Figs. 11 and 22 show a flow of a series of operations. Operations from SI20 to SI27 in Fig. 22 are similar to the operations disclosed in the present embodiment described above. The operations shown in Fig. 22 differ from the operations shown in Fig. 12 in that S128 has been inserted between S122 and S123. [0072]
Figs. 23 and 24 are diagrams showing a transition of an amplitude of a variation having occurred in a sensor signal. In Figs. 23 and 24, ordinates represent band-pass filter output that is a value corresponding to an amplitude of a variation having occurred in the sensor signal. Abscissas represent the number of times the elevator is started. Alternatively, the abscissas in Figs. 23 and 24 may represent, for example, an elapsed time since installation of the elevator. [0073]
Fig. 23 shows a transition of the output signal Y obtained when the car 1 passes the position Pi. Until the elevator is started for the M4-th time, the broken portion 4c does not occur in the main rope 4. Fig. 23 shows an example in which the broken portion 4c occurs in the main rope 4 when the elevator is started for the M5-th time. In the example shown in Fig. 23, a value of the output signal Y suddenly increases in comparison to an immediately previous value when the elevator is started for the M5-th time. [0074]
Fig. 24 shows a transition of the output signal Y obtained when the car 1 passes the position P4. As described above, a variation in the sensor signal attributable to a joint of the rails 30 gradually increases over time. In the example shown in Fig. 24, the output signal Y does not exceed the threshold TH2 until the elevator is started for the M4-th time. However, the output signal Y exceeds the threshold TH2 when the elevator is started for the M5-th time. The example shown in Fig. 23 and the example shown in Fig. 24 are consistent with each other in that the output signal Y exceeds the threshold TH2 for the first time when the elevator is

started for the M5-th time. Fig. 22 shows an operation example in which a variation having occurred in the sensor signal can be differentiated, even in the examples shown in Figs. 23 and 24, as to whether the variation is attributable to the broken portion 4c or the variation is attributable to a joint of the rails 30. [0075]
The abnormal variation detection unit 22 detects an abnormal variation in the sensor signal (SI01). In addition, the reproducibility determination unit 23 detects a reproducibility of the variation that occurs in the sensor signal (SI 02). [0076]
Next, the break determination unit 24 determines a presence or absence of the broken portion 4c (SI03). For example, when the break determination unit 24 causes the number of times the threshold TH2 is exceeded to be stored in the storage unit 20 in SI22, the break determination unit 24 determines whether or not the number of times the output signal Y has exceeded the threshold TH1 at the same position is equal to or smaller than a prescribed number of times (S128). As shown in Fig. 23, when the broken portion 4c occurs in the main rope 4, the output signal Y suddenly increases. Therefore, when it is determined in S128 that the number of times the threshold TH1 is exceeded is equal to or smaller than the prescribed number of times, it is likely that the broken portion 4c has occurred in the main rope 4. When the number of times the threshold TH1 is exceeded is equal to or smaller than the prescribed number of times in SI 28, the break determination unit 24 advances to the process indicated in S123. [0077]
On the other hand, as shown in Fig. 24, when oil applied to the rails 30 becomes depleted, the output signal Y increases gradually. Therefore, when it is determined in SI28 that the number of times the threshold TH1 is exceeded is not equal to or smaller than the prescribed number of times, a determination can be made that the detection of the output signal Y exceeding the threshold TH2 is attributable to a slight variation. When the number of times the threshold TH1 is exceeded is not equal to or smaller than the prescribed number of times in S128, the break determination unit 24 advances to the process indicated in S121. [0078]
The prescribed number of times that is compared with the number of times the threshold TH1 is exceeded in SI28 is stored in advance in, for example, the storage unit 20.

The prescribed number of times is set to, for example, three or more times. [0079]
In the operation example shown in Fig. 22, even if a car position at the moment the variation in the sensor signal exceeds the threshold TH1 is reproducible, the break determination unit 24 does not determine that the broken portion 4c is present in the main rope 4 when the number of times the threshold TH1 is exceeded before the variation in the sensor signal exceeds the threshold TH2 at the reproducible position is larger than a prescribed number of times. The break determination unit 24 determines that, for example, the variation is attributable to passing a joint of the rails 30. As a result, detection accuracy of the broken portion 4c can be further improved. [0080]
Fig. 25 is a flow chart showing another operation example of the break detecting device according to the first embodiment of the present invention. Fig. 25 shows a flow of operations that follows Fig. 11. In other words, Figs. 11 and 25 show a flow of a series of operations. Operations from SI20 to SI28 in Fig. 25 are similar to the operations disclosed in the present embodiment described above. The operations shown in Fig. 25 differ from the operations shown in Fig. 22 in that S129 is provided after a negative determination (NO) is made in SI28. [0081]
Fig. 26 is a diagram showing a transition of an amplitude of a variation having occurred in a sensor signal. In Fig. 26, an ordinate represents band-pass filter output that is a value corresponding to an amplitude of a variation having occurred in the sensor signal. An abscissa represents an elapsed time since installation of the elevator. The abscissa in Fig. 26 may represent the number of times the elevator is started. [0082]
Fig. 26 shows an example in which the broken portion 4c occurs in the main rope 4 when a time T2 has elapsed. In addition, Fig. 26 shows an example in which the broken portion 4c comes into contact with a rope guide at a position where the car 1 passes a joint of the rails 30. Fig. 25 shows an operation example in which a variation having occurred in the sensor signal can be differentiated, even in the example shown in Fig. 26, as to whether the variation is attributable to the broken portion 4c or the variation is attributable to a joint of the rails 30.

[0083]
The abnormal variation detection unit 22 detects an abnormal variation in the sensor signal (S101). In addition, the reproducibility determination unit 23 detects a reproducibility of the variation that occurs in the sensor signal (SI 02). [0084]
Next, the break determination unit 24 determines a presence or absence of the broken portion 4c (S103). For example, when the break determination unit 24 causes the number of times the threshold TH2 is exceeded to be stored in the storage unit 20 in SI22, the break determination unit 24 determines whether or not the number of times the output signal Y has exceeded the threshold TH1 at the same position is equal to or smaller than a prescribed number of times (S128). When the break determination unit 24 determines in S128 that the number of times the threshold TH1 is exceeded is equal to or smaller than the prescribed number of times, the break determination unit 24 advances to the process indicated in SI23. [0085]
When the break determination unit 24 determines in SI 28 that the number of times the threshold TH1 is exceeded is not equal to or smaller than the prescribed number of times, the break determination unit 24 calculates a difference y between a latest value and a value immediately before the latest value of the output signal Y at the same position. In addition, the break determination unit 24 determines whether or not the calculated difference y is equal to or larger than a reference value a (SI29). As shown in Fig. 26, when the broken portion 4c has not occurred in the main rope 4, the output signal Y gradually increases. Therefore, when it is determined in SI29 that the difference y is not equal to or larger than the reference value a, a determination can be made that the detection of the output signal Y exceeding the threshold TH2 is attributable to a slight variation. When the difference y is not equal to or larger than the reference value a in S129, the break determination unit 24 advances to the process indicated in S121. [0086]
On the other hand, as shown in Fig. 26, when the broken portion 4c has occurred in the main rope 4, the output signal Y suddenly increases. Therefore, when it is determined in SI29 that the difference y is equal to or larger than the reference value a, a determination can be made that the broken portion 4c has occurred in the main rope 4. When the difference y is equal to or larger than the reference value a in SI29, the break determination unit 24 advances to the

process indicated in SI24. [0087]
In the operation example shown in Fig. 25, when a negative determination (NO) is made in SI 28, the break determination unit 24 determines the presence or absence of the broken portion 4c on the basis of a comparison between the difference y and the reference value a. A negative determination (NO) is made in S128 when a car position at the moment the variation in the sensor signal exceeds the threshold TH1 is reproducible and, at the same time, when the number of times the threshold TH1 is exceeded before the variation in the sensor signal exceeds the threshold TH2 at the reproducible position is larger than a prescribed number of times. When the difference y is not equal to or larger than the reference value a, the break determination unit 24 does not determine that the broken portion 4c is present in the main rope 4. The break determination unit 24 determines that, for example, the variation in the sensor signal is attributable to passing a joint of the rails 30. As a result, detection accuracy of the broken portion 4c can be further improved. [0088]
Figs. 27 and 28 are flow charts showing another operation example of the break detecting device according to the first embodiment of the present invention. Figs. 27 and 28 show a flow of operations that follows Fig. 11. In other words, Figs. 11,27, and 28 show a flow of a series of operations. Operations from S120 to S129 In Figs. 27 and 28 are similar to the operations disclosed in the present embodiment described above. The operations shown in Figs. 27 and 28 differ from the operations shown in Fig. 25 in that S130 to S132 are provided after S129. Figs. 27 and 28 show another operation example in which the differentiation described above can be made even when the broken portion 4c comes into contact with a rope guide at a position where the car 1 passes a joint of the rails 30. [0089]
The abnormal variation detection unit 22 detects an abnormal variation in the sensor signal (S101). In addition, the reproducibility determination unit 23 detects a reproducibility of the variation that occurs in the sensor signal (SI 02). [0090]
Next, the break determination unit 24 determines a presence or absence of the broken portion 4c (S103). For example, when the break determination unit 24 determines in S128 that the number of times the output signal Y has exceeded the threshold TH1 is not equal to or

smaller than the prescribed number of times, the break determination unit 24 determines whether or not the difference y is equal to or larger than the reference value a (S129). When the break determination unit 24 determines in SI29 that the difference y is equal to or larger than the reference value a, the break determination unit 24 causes the fact that the difference y being equal to or larger than the reference value a is detected at the same position to be stored in the storage unit 20 (S130). In this case, the operation control unit 25 controls a normal operation (SI27). [0091]
When the difference y is not equal to or larger than the reference value a in SI29, the break determination unit 24 determines whether or not the difference y that is equal to or larger than the reference value a has been detected until the output signal Y reaches the threshold TH2 after exceeding the threshold TH1 at the same position (S131). When the break determination unit 24 determines in S131 that the difference y that is equal to or larger than the reference value a has not been detected, the break determination unit 24 advances to the process indicated in S121. [0092]
On the other hand, when the difference y that is equal to or larger than the reference value a is detected in S131, the break determination unit 24 determines whether or not the number of times the output signal Y has exceeded the threshold TH2 at the same position is a plurality of times (S132). When the break determination unit 24 determines in S132 that the number of times the threshold TH2 is exceeded is not a plurality of times, the operation control unit 25 controls a normal operation (S127). When the number of times the threshold TH2 is exceeded is a plurality of times in SI 32, the break determination unit 24 advances to the process indicated in SI24. [0093]
In SI32, the break determination unit 24 may determine whether or not the number of times the threshold TH2 is exceeded has reached a prescribed number of times. In this case, when the number of times the threshold TH2 is exceeded has reached the prescribed number of times, the break determination unit 24 determines that the broken portion 4c has occurred in the main rope 4 (S124). On the other hand, when the number of times the threshold TH2 is exceeded has not reached the prescribed number of times, the operation control unit 25 controls a normal operation (SI 27). The prescribed number of times is set to, for example, three or

more times.
[0094]
Second Embodiment
In the first embodiment, an example has been described in which a variation in the sensor signal is stored in the storage unit 20 in association with a car position regardless of a direction of travel of the car 1. However, depending on a direction in which the broken portion 4c protrudes, a manner in which the broken portion 4c strikes a rope guide differs when the direction of travel of the car 1 changes. For example, when the broken portion 4c protrudes as in the example shown in Fig. 13, the manner in which the broken portion 4c strikes the right-side rope guide 19 differs between a case where the broken portion 4c strikes the rope guide 19 from below and a case where the broken portion 4c strikes the rope guide 19 from above. [0095]
Fig. 29 is a flow chart showing an operation example of the break detecting device according to a second embodiment of the present invention. Fig. 29 shows an example in which the operations shown in Fig. 10 are separately performed in accordance with a direction of travel of the car 1. In the example described in the present embodiment, first, the direction of travel of the car 1 is determined (S104). Operations from S101U to S103U in Fig. 29 are similar to the operations indicated in S101 to SI03 which have been disclosed in the first embodiment. In a similar manner, operations from S101D to S103D in Fig. 29 are similar to the operations indicated in SI01 to SI03 which have been disclosed in the first embodiment. [0096]
In the example described in the present embodiment, a car position during an ascent and a car position during a descent are treated as different positions. In other words, in the example shown in Fig. 15, a car position at the time ti and a car position at the time t3 are considered a same position. In addition, a car position at the time t2 and a car position at the time U are considered a same position. However, the car position at the time ti and the car position at the time t2 are not considered a same position. In a similar manner, the car position at the time t3 and the car position at the time U are not considered a same position. With the break detecting device described in the present embodiment, detection accuracy of the broken portion 4c can be further improved. [0097]

Third Embodiment
In the first and second embodiments, examples in which the presence or absence of the broken portion 4c is determined using one sensor signal have been described. In the present embodiment, an example in which the presence or absence of the broken portion 4c is determined using a plurality of sensor signals will be described. Although three or more sensor signals may be used, in the present embodiment, an example in which the presence or absence of the broken portion 4c is determined using two sensor signals will be described as a simplest example. [0098]
Fig. 30 is a diagram for illustrating an example of functions of the abnormal variation detection unit 22. The abnormal variation detection unit 22 includes, for example, band-pass filters 27a and 27b, amplifiers 28a and 28b, determiners 29a and 28b, and a determiner 31. For example, the band-pass filter 27a extracts a signal component in a band of characteristic frequency from a torque signal. The amplifier 28a squares an output signal ul from the band-pass filter 27a to amplify the signal. The determiner 29a determines whether or not an output signal Yl from the amplifier 28a exceeds the threshold TH1. [0099]
For example, the band-pass filter 27b extracts a signal component in a band of characteristic frequency from a load signal. The amplifier 28b squares an output signal u2 from the band-pass filter 27b to amplify the signal. The determiner 29b determines whether or not an output signal Y2 from the amplifier 28b exceeds the threshold TH1. [0100]
The determiner 31 determines whether or not the output signals Yl and/or Y2 exceed the threshold TH1. When neither the output signal Yl nor the output signal Y2 exceeds the threshold TH1, a normal operation is performed. When at least one of the output signals Yl and Y2 exceeds the threshold TH1, a process for making a transition to the process by the reproducibility determination unit 23 is performed. The operation described above by the determiner 31 corresponds to the determination in SI 12. [0101]
Fig. 31 is a diagram for illustrating an advantage of using a plurality of sensor signals. Fig. 31 is a gain diagram showing a magnitude of a variation level of the sensor signals when the broken portion 4c collides with a rope guide provided on the return pulley 7. Gl denotes a

gain from an external force to an angular velocity of the traction machine 11. G2 denotes a
gain from an external force to a load signal.
[0102]
In the gain Gl, an antiresonance point F2 exists between a first-order natural frequency Fl and a second-order natural frequency F3. In addition, an antiresonance point F4 exists between the second-order natural frequency F3 and a third-order natural frequency F5. If a value of a frequency of an abnormal variation (vibration) when the broken portion 4c collides with the rope guide is close to the antiresonance point F2 or F4, it is difficult to detect the abnormal variation from a torque signal. On the other hand, the gain G2 is higher than the gain Gl at the frequency and is characteristically more sensitive. Therefore, when an abnormal variation is detected at a frequency that is close to the antiresonance point F2 or F4, the abnormal variation is more readily detected from a load signal than from a torque signal. [0103]
Examples of detecting the broken portion 4c having occurred in the main rope 4 have been described in the respective embodiments. The break detecting device may detect a broken portion that occurs in other ropes used in the elevator. [0104]
Each of the units denoted by reference numerals 20 to 26 and the threshold setting unit represent functions included in the controller 13. Fig. 32 is a diagram showing a hardware configuration of the controller 13. For example, as hardware resources, the controller 13 is provided with processing circuitry including a processor 32 and a memory 33. The controller 13 may realize each of the functions by executing a program stored in the memory 33 using the processor 32. [0105]
The processor 32 is also referred to as a CPU (Central Processing Unit), a central processor, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, or a DSP. As the memory 33, a semiconductor memory, a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini disc, or a DVD may be adopted. The adoptable semiconductor memories include a RAM, a ROM, a flash memory, an EPROM, and an EEPROM. [0106]
A part of or all of the respective functions of the controller 13 may be realized by hardware. As the hardware for realizing the functions of the controller 13, a single circuit, a

composite circuit, a programmed processor, a parallel-programmed processor, an ASIC, an FPGA, or a combination thereof may be adopted.
Industrial Applicability [0107]
The break detecting device according to the present invention is applicable to a break detecting device that detects a broken portion having occurred in a rope of an elevator. Reference Signs List [0108]
1 car, 2 shaft, 3 counterweight, 4 main rope, 4a end
portion, 4b end portion, 4c broken portion, 5 suspension sheave, 6
suspension sheave, 7 return pulley, 8 driving sheave, 9 return pulley,
9a shaft, 10 suspension sheave, 11 traction machine, 12 load weighing
device, 13 controller, 15 governor, 16 governor rope, 17 governor
sheave, 18 encoder, 19 rope guide, 20 storage unit, 21 car position
detection unit, 22 abnormal variation detection unit, 23 reproducibility
determination unit, 24 break determination unit, 25 operation control unit,
26 notification unit, 27 band-pass filter, 28 amplifier, 29 determiner,
30 rail, 31 determiner, 32 processor, 33 memory

[Claim l]
A break detecting device, comprising:
a sensor of which an output signal varies when a vibration is generated in a rope of an elevator;
storage means confgured to store a variation in the output signal fom the sensor in association with a position of a car of the elevator; and
break determination means confgured to determine, on the basis of the position of the car and a transition of the variation in the output signal fom the sensor, whether or not a broken portion is present in the rope. [Claim 2]
A break detecting device, comprising:
a sensor of which an output signal varies when a vibration is generated in a rope of an elevator;
storage means confgured to store a variation in the output signal fom the sensor in association with a position of a car of the elevator; and
break determination means confgured to deterine, on the basis of a reproducibility of the position of the car at a moment the variation in the output signal fom the sensor exceeds a frst threshold and a reproducibility of the position of the car at a moment the variation in the output signal fom the sensor exceeds a second threshold that is larger than the frst threshold, whether or not a broken porion is present in the rope. [Claim 3]
The break detecting device according to claim 2, wherein the break determination means is confgured not to determine that a broken portion is present in the rope when the variation in the output signal fom the sensor does not exceed the second threshold even when the position of the ca at the moment the variation in the output signal fom the sensor exceeds the frst threshold is reproducible. [Claim 4]
The break detecting device according to claim 2, wherein the break determination means is confgured not to determine that a broken portion is present in the rope even when the position of the car at the moment the variation in the output signal fom the sensor exceeds the frst threshold is reproducible when the number of times the variation in the output signal fom

the sensor exceeds the first threshold before exceeding the second threshold at the reproducible position is larger than a prescribed number of times. [Claim 5]
The break detecting device according to claim 2, wherein
the break determination means is configured to:
determine, when the position of the car at the moment the variation in the output signal from the sensor exceeds the first threshold is reproducible and, at the same time, the number of times the variation in the output signal from the sensor exceeds the first threshold before exceeding the second threshold at the reproducible position is larger than a prescribed number of times, whether or not a difference between a latest value and a value immediately before the latest value of the variation in the output signal from the sensor at the reproducible position is equal to or larger than a reference value; and
determine that a broken portion is present in the rope when the difference is equal to or larger than the reference value. [Claim 6]
The break detecting device according to claim 5, wherein the break determination means is configured not to determine that a broken portion is present in the rope when the difference is not equal to or larger than the reference value. [Claim 7]
The break detecting device according to any one of claims 2 to 6, further comprising abnormal variation detection means configured to detect a variation in an output signal from the sensor and determine whether or not the detected variation exceeds the first threshold. [Claim 8]
The break detecting device according to claim 7, wherein the abnormal variation detection means is configured to extract a signal component in a band of characteristic frequency which is created as a broken portion present in the rope comes into contact with a rope guide for the rope. [Claim 9]
The break detecting device according to claim 8, wherein when a speed of movement of the rope is denoted by v [m/s] and a value set as a length of a broken portion that occurs in the rope is denoted by d [m], the characteristic frequency includes a frequency f [Hz] expressed by

f=v/d. [Claim 10]
The break detecting device according to any one of claims 2 to 9, further comprising threshold setting means configured to set the first threshold and the second threshold on the basis of the variation in the output signal from the sensor. [Claim 11]
The break detecting device according to any one of claims 2 to 10, 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 or a load signal from a load weighing device that detects a load of the car. [Claim 12]
The break detecting device according to any one of claims 2 to 11, further comprising:
a second sensor configured to output a signal in accordance with a position of the car; and
car position detection means configured to detect a position of the car on the basis of a signal output from the second sensor. [Claim 13]
The break detecting device according to claim 12, wherein the signal output from the second sensor is an encoder signal from a traction machine having a driving sheave around which the rope is wound or an encoder signal from a governor for operating a safety gear included in the car.