CN114620579B - Elevator rope inspection system - Google Patents

Abstract

The invention provides a rope inspection system of an elevator. Even when a mark defect occurs, it is possible to continue measurement of the mark interval, judge rope elongation from the measurement result, and perform highly reliable strength management. The rope inspection system for an elevator according to one embodiment is provided with a rope having a structure in which a car and a counterweight are suspended via a traction sheave of a hoisting machine and a surface is coated with resin, and measures the intervals of a plurality of marks provided on the surface of the rope at regular intervals. The rope inspection system includes a control device having a reference value for the mark interval of the rope, and when the mark interval obtained as a measurement result is within an allowable range defined by an integer multiple of the reference value, the control device validates the measurement result and determines rope elongation based on the measurement result.

Description

Elevator rope inspection system

The present application is based on Japanese patent application 2020-204202 (filing date: 12/9/2020), and enjoys priority of the application. The present application is incorporated by reference in its entirety.

Technical Field

Embodiments of the present invention relate to a rope inspection system for an elevator.

Background

A machine-room-less elevator is widely used in which space is saved by housing elevator equipment such as a hoisting machine in a hoistway. In an elevator of the machine room-less type, a sheave (traction sheave) of a hoisting machine is miniaturized. Therefore, as a main rope having a rope structure in which bending fatigue is less likely to occur and high strength, a steel rope in which the surface of a tensile characteristic member is covered with a resin material having abrasion resistance and a high coefficient of friction such as polyurethane is used.

Such a wire rope cannot visually observe the tensile characteristic member inside, and cannot perform strength control by visually checking the wear state and the number of broken wires as in a general wire rope. Thus, the following rope inspection system is proposed: the strength is controlled by applying marks at substantially constant intervals on the surface of the rope, and measuring the mark intervals relative to the amount of feed of the rope as rope elongation, thereby determining the degradation state based on the measurement result.

The mark is optically detected by a photoelectric sensor when the rope is moving. However, the condition that the photoelectric sensor cannot detect a part of each mark on the rope is brought about due to the use environment, aging, and the like of the rope. This state is referred to as "mark shortage". In such a case, the degradation state of the rope (rope elongation) cannot be accurately determined based on the measurement result of the mark interval, and therefore only the rope can be replaced.

In addition, if a plurality of photoelectric sensors are arranged for one rope, the detection rate of the mark is improved, so that the mark shortage can be prevented. However, it is difficult to dispose a plurality of photosensors in a limited space in the hoistway, and the cost of the system increases.

Disclosure of Invention

The object of the present invention is to provide a rope inspection system for an elevator, which can continuously measure a mark interval even if a mark defect occurs, judge rope elongation according to the measurement result, and manage intensity with high reliability.

The rope inspection system according to one embodiment is provided with a rope for suspending a car and a counterweight via a traction sheave of a hoisting machine, and has a structure in which a surface is coated with resin, and the rope inspection system measures a spacing of a plurality of marks provided at a fixed spacing on the surface of the rope.

The rope inspection system for an elevator includes a sensor, a mark detection processing unit, a mark interval calculation processing unit, and a control device. The sensor is disposed in the vicinity of the rope. The mark detection processing unit detects the position of each mark based on a signal output from the sensor and data indicating the lifting position of the car as the rope moves. The mark interval calculation processing unit calculates a mark interval based on the position of each mark detected by the mark detection processing unit. The control device has a reference value for the marking interval of the rope, and when the marking interval obtained by the marking interval calculation processing unit as a measurement result is within an allowable range defined by an integer multiple of the reference value, the control device validates the measurement result and determines rope elongation based on the measurement result.

According to the rope inspection system of the elevator with the above configuration, even when the mark is missing, the measurement of the mark interval can be continued, and the rope elongation can be determined based on the measurement result, thereby performing the intensity management with high reliability.

Drawings

Fig. 1 is a schematic diagram showing the structure of an elevator according to embodiment 1.

Fig. 2 is a cross-sectional view showing a structure of a main rope used in the elevator according to the embodiment.

Fig. 3 is a perspective view showing an external appearance of a main rope used in the elevator according to the embodiment.

Fig. 4 is a diagram for explaining a relationship between a pulse signal and a marking interval in this embodiment, where (a) of fig. 4 is a pulse signal output in synchronization with movement of a main rope, (b) of fig. 4 is a marking interval at the time of installation, and (c) of fig. 4 is a marking interval at the time of rope elongation due to aged deterioration.

Fig. 5 is a diagram showing a relationship between elongation and residual strength associated with degradation of the rope according to the embodiment.

Fig. 6 is a diagram for explaining a method of measuring a mark interval using the sensor according to the embodiment, fig. 6 (a) is a diagram showing an output voltage of the sensor, and fig. 6 (b) is a diagram showing a relationship between the output voltage of the sensor and a mark position.

Fig. 7 is a diagram showing an example of the result of the operation of the mark interval according to this embodiment, and shows the result of the operation of the mark interval when no mark is missing.

Fig. 8 is a diagram showing an example of the result of the operation of the mark interval according to this embodiment, and shows the result of the operation of the mark interval when the mark defect occurs at 1.

Fig. 9 is a diagram showing an example of the result of the operation of the mark interval in the embodiment, and shows the result of the operation of the mark interval when the mark deficiency is continuously generated.

Fig. 10 is a flowchart for explaining a processing operation of the main flow of the rope inspection system of the embodiment.

Fig. 11 is a flowchart for explaining the length measurement operation process included in the main flow.

Fig. 12 is a flowchart for explaining the mark detection process included in the main flow.

Fig. 13 is a flowchart for explaining the mark interval calculation processing included in the main flow.

Fig. 14 is a flowchart for explaining the mark interval arithmetic processing included in the main flow.

Fig. 15 is a diagram for explaining the threshold voltage adjustment method according to embodiment 2, and is a diagram showing the threshold voltage adjustment method when the number of mark detections is small.

Fig. 16 is a diagram for explaining the threshold voltage adjustment method according to embodiment 2, and is a diagram showing the threshold voltage adjustment method when the number of mark detections is large.

Fig. 17 is a flowchart for explaining the mark detection process according to embodiment 2.

Fig. 18 is a flowchart for explaining the mark detection process according to embodiment 2.

Fig. 19 is a flowchart for explaining the mark detection process according to embodiment 3.

Fig. 20 is a flowchart for explaining the mark detection process according to embodiment 3.

Detailed Description

Hereinafter, embodiments will be described with reference to the drawings.

First, before explaining the embodiment of the present invention, a relationship between elongation and strength of a rope will be described with reference to fig. 5.

For example, a wire rope used for a main rope of an elevator or the like is formed by drawing strands and cores, which are tensile members, by tension and rubbing each other by bending received from a sheave or the like. Therefore, in the mode of rope degradation, abrasion and breakage of the wire rod in the vicinity of the core wire dominate. Since the strands move in the direction of the core wire (the direction in which the rope diameter decreases) due to degradation of the portion, elongation occurs as a rope structure.

The steel cable having such a structure was verified, and as a result, it was found that there was a correlation between elongation and strength as shown in fig. 5. In fig. 5, the horizontal axis represents the elongation of the rope. Specific numerical values are omitted for confidential reasons, but λ in the figure is about several% and the distance is about several mm. The vertical axis represents the strength ratio of the rope (this is referred to as the residual strength ratio). When the rope is gradually elongated due to aging from a new state at the time of installation, the strength is also lowered with it. In a normal case, safety can be obtained by determining the strength ratio of 80% as the reference strength and setting the time when the elongation of the rope becomes λ as the replacement time.

The rope is fed by a certain amount by the inspection operation, a plurality of marks attached to the surface of the rope are detected by the sensor during this period, and the pulse signal of the encoder is counted at the detection timing thereof, whereby the rope elongation is measured.

As a method of generating a pulse signal for measuring a mark, for example, when a rotary encoder is used in which a rotary member is brought into contact with a guide rail, a pulse number corresponding to a constant rope feed amount varies due to a step of a track joint, an attached matter, or the like, and an error is likely to occur in measuring a mark interval. In addition, there is a method of providing an encoder to a governor, but an extra space is required including a checking work space.

Therefore, an encoder for controlling the rotation of the hoisting machine in synchronization with the rotation of the traction sheave is considered. If this encoder is used, it is not necessary to provide an extra space such as an encoder for the governor, and the cost can be reduced.

However, the reflectance of the mark portion decreases and the output of the mark detection sensor decreases due to the rope use environment, aging, etc., and mark deficiency occurs at a certain mark detection threshold, so that the mark interval measurement cannot be performed. Here, although a plurality of mark detection sensors can be provided to compensate for mark detection, this leads to an increase in the cost of the system. In addition, when an inexpensive photoelectric microsensor is used as the mark detection sensor, for example, an output difference is generated due to individual differences of the sensors, and a mark defect frequently occurs under a predetermined mark detection threshold value, so that a mark interval cannot be measured. When a high-precision sensor having a small output difference is used as a countermeasure, the cost is further increased.

Hereinafter, a method for continuing measurement of a mark interval without impairing measurement accuracy even when a mark defect occurs will be described in detail.

(embodiment 1)

Fig. 1 is a schematic diagram showing the structure of an elevator according to embodiment 1. In the example of fig. 1, an elevator of the machine room-less type without machine room is assumed.

The car 20 and the counterweight 21 are supported to be liftable by guide rails 11 and 12 erected in the hoistway 10, respectively. Further, a hoisting machine 23 having a traction sheave 22 is provided at an upper portion of the hoistway 10. The car 20 and the counterweight 21 are suspended in the hoistway 10 by a plurality of main ropes 24. In fig. 1, only one main rope 24 is shown, and the other main ropes 24 are omitted.

Both ends of the main rope 24 are fixed to the upper end of the hoistway 10 via rope buckles 25a and 25b, respectively. The main rope 24 is continuously wound around the car sheave 26, the traction sheave 22, and the counterweight sheave 27 at the intermediate portion. Thus, by 2:1 to support the car 20 and counterweight 21. When the traction sheave 22 rotates by the driving of the hoisting machine 23, the car 20 and the counterweight 21 perform lifting and lowering operations in a bucket manner in the hoistway 10 via the main rope 24 as the traction sheave 22 rotates.

In the elevator of the machine room-less type without a machine room, the hoisting machine 23 is provided in the hoistway 10, but the present invention is not limited to this configuration, and may be an elevator with a machine room. In an elevator having a machine room, a traction machine 23 is provided in the machine room. The rope hanging method is not limited to 2 as shown in fig. 1: the 1-string method may be, for example, 1:1 hanging rope method and other modes.

Here, the rope inspection system of the present embodiment includes a sensor 28, an encoder 29, an arithmetic device 30, a display device 31, and a control panel 40.

The sensor 28 is provided near the main rope 24 as an inspection target, and optically detects a plurality of marks 45 (see fig. 3) provided at regular intervals in the longitudinal direction of the main rope 24. The encoder 29 generates a pulse signal in synchronization with the rotation of the traction sheave 22. The encoder 29 is an encoder provided in the elevator to detect the position and speed of the car. By using this encoder 29 for the measurement of the mark interval, for example, a layout defect that is a problem in the configuration of providing the encoder to the governor can be avoided.

The arithmetic device 30 samples the output voltage of the sensor 28 at a predetermined cycle and stores the sampled output voltage in the memory (storage device) 30a, and counts the pulse signal generated by the encoder 29 and stores the counted pulse signal in the memory 30a. In addition, since the main rope 24 is actually constituted by a plurality of ropes, the arithmetic device 30 stores the output voltage of the sensor 28 and the count value of the pulse signal in the memory 30a at a constant cycle for each rope.

The arithmetic device 30 includes: a function (mark detection processing section) of detecting the positions of the marks 45 based on the output voltage V and the threshold voltage Vs of the sensor 28 stored in the memory 30a, and counting the number of the marks 45 (mark detection number); and a function (mark interval calculation processing unit) for calculating the mark interval based on the count value of the pulse signal generated by the encoder 29. The arithmetic device 30 also has a function of obtaining the elongation of the main rope 24 from the mark interval. The display device 31 displays the mark interval, the rope elongation, and the like obtained by the operation device 30. The computing device 30 and the display device 31 are composed of general-purpose computers. The structure may be as follows: the control panel 40 is provided with the function of the arithmetic unit 30, and a series of processes related to measurement of the mark interval are performed only by the control panel 40.

The control panel 40 is a control device for controlling the entire elevator including the drive control of the hoisting machine 23. The control panel 40 detects the position of the car 20 based on the pulse signal of the encoder 29, and performs control such as moving the car 20 to a destination floor at a predetermined speed. In the present embodiment, the arithmetic device 30 is connected to the control panel 40, and the arithmetic device 30 acquires the pulse signal of the encoder 29 from the control panel 40.

The control panel 40 is connected to a monitoring center 51 via a communication network 50. The monitoring center 51 remotely monitors the states of the elevators of the respective buildings to be monitored via the communication network 50, and when some abnormality or the like occurs, performs a response such as sending maintenance personnel to the site. The maintenance person holds a terminal device 52 for maintenance inspection. The terminal device 52 has a function of performing wireless communication with the control panel 40 and the monitoring center 51.

The reference numeral 32 denotes a stop detecting means. The stop detecting member 32 is also referred to as a "stop detecting plate" and is provided for each floor in the hoistway 10 along the lifting direction of the car 20. The stop detecting means 32 is for detecting a stop position in conjunction with the non-contact switch 33 when the car 20 stops at each floor.

Here, the structure of the main rope 24 will be described with reference to fig. 2 and 3.

As the main rope 24, a resin-coated wire rope is used. As shown in fig. 2, the main rope 24 includes a rope main body 41 as a tensile characteristic member and an outer coating layer 42 that entirely covers the rope main body 41 as main elements.

The rope main body 41 is constituted by twisting a plurality of steel strands 43 at predetermined intervals. The outer coating layer 42 is formed of a thermoplastic resin material having abrasion resistance and a high coefficient of friction, such as polyurethane. The outer coating 42 has an outer peripheral surface 44a defining the outer surface of the main rope 24. The outer peripheral surface 44a has a circular cross-sectional shape, and contacts with friction when being wound around the sheaves 22, 26, 27.

Further, the resin material forming the outer coating layer 42 fills in the gaps between the adjacent strands 43. Therefore, the outer coating layer 42 has a plurality of filling portions 44 that enter between the strands 43 adjacent in the circumferential direction of the rope main body 41. The filling portion 44 is located inside the outer peripheral surface 44a of the outer coating layer 42.

As shown in fig. 3, a plurality of marks 45 are provided on the surface of the main rope 24 (i.e., the outer peripheral surface 44a of the outer coating layer 42). These marks 45 are elements for detecting the elongation due to degradation of the main rope 24, and are arranged at regular intervals (for example, 500mm intervals) in the longitudinal direction over the entire length of the main rope 24. Each of these marks 45 is formed of a straight line continuous in the circumferential direction of the main rope 24 or an intermittent broken line.

However, the main rope 24 is such that, as the use period passes, the gaps between the strands 43 and the gaps between the plurality of wires constituting the strands 43 decrease. This repeatedly rubs the strands 43 and wires, and abrasion and breakage of the strands 43 and wires develop.

In particular, friction is repeatedly applied to the portions of the main rope 24 that contact the sheaves 22, 26, 27. Therefore, the main rope 24 is worn and broken more than the portion of the main rope 24 that does not pass through the sheaves 22, 26, 27, and the rope diameter is reduced or local elongation occurs. Accordingly, the relationship between the rope elongation and the strength reduction rate is clarified, and the strength of the main rope 24 can be controlled by detecting the elongation of the portion of the main rope 24 that is most deteriorated.

The sensor 28 is fixed near the hoisting machine 23 so as to face the main rope 24, for example. Thus, when the car 20 is lifted and lowered between the uppermost and lowermost floors by the inspection operation, most of the entire length of the main rope 24 passes the sensor 28 except for the portions near the rope buckles 25a and 25b, and the mark 45 can be continuously detected when it passes.

For the sake of responsiveness, the sensor 28 is desirably constituted by a photoelectric sensor using laser light reflected light, but may be constituted by a photoelectric microsensor or the like using LED light reflected light at a lower cost. Among photoelectric sensors on the market, the following sensors have been popular in recent years: the object is irradiated with a laser beam or the like, and a change in the surface color (reflectance) is detected from the difference in reflected light intensity (reflectance).

The encoder 29 outputs a pulse signal in synchronization with the movement of the car 20, and thus becomes a pulse output corresponding to approximately the rope feed amount. The marks 45 are arranged at equal intervals in the longitudinal direction of the main rope 24 when the elevator is installed. Therefore, when there is no elongation due to degradation of the main rope 24, the count value of the pulse signal is substantially the same as a reference value corresponding to the mark interval at the time of installation. On the other hand, when the main rope 24 is elongated due to degradation of the main rope 24, the count value of the pulse signal exceeds the reference value corresponding to the mark interval at the time of installation.

This is shown in fig. 4.

Fig. 4 is a diagram for explaining a relationship between a pulse signal and a marking interval, where (a) of fig. 4 is a pulse signal output in synchronization with movement of the main rope 24, (b) of fig. 4 is a marking interval at the time of installation, and (c) of fig. 4 is a marking interval at the time of rope elongation due to aging.

When the reference value at the time of counting the pulse signals at the mark interval at the time of installation is set to n pulses, the count value obtained by the inspection operation contains a small error and is substantially the same as the n pulses at the time of installation without degradation of the main rope 24. However, when the main rope 24 is in an extended state due to degradation, the count value obtained by the inspection operation becomes greater than n pulses corresponding to the mark interval at the time of installation.

Here, measurement of the mark interval will be described with reference to fig. 6.

Fig. 6 is a diagram for explaining a measurement method of a mark interval using the sensor 28, and fig. 6 (a) is a diagram showing an output voltage of the sensor 28, and fig. 6 (b) is a diagram showing a relationship between the output voltage of the sensor 28 and the mark position P.

Currently, the main rope 24 is fed in the direction of arrow a shown in fig. 1. The sensor 28 has an analog voltage output function, and outputs an output voltage V corresponding to the reflectivity of the unlabeled portion and the marked portion of the main rope 24. The output voltage V of the sensor 28 and the number of accumulated pulses obtained by accumulating the pulses output from the encoder 29 are stored in the memory 30a of the arithmetic device 30 at a predetermined period. The output voltage V stored in the memory 30a is compared with the threshold voltage Vs. Then, at the timing of the rise when the output voltage V exceeds the threshold voltage Vs, the rise and fall position obtained by multiplying the pulse rate by the number of accumulated pulses counted during the period is obtained as the mark positions P1, P2, P3 … … Pn, and sequentially stored in the memory 30a. Thus, the lifting position and the mark interval of the car 20 are obtained as in the following equations (1) and (2 a) to (2 c).

Lifting position = accumulated number of pulses x pulse rate … … (1)

Mark interval l1= |p1—p2| … … (2 a)

Mark space l2= |p2—p3| … … (2 b)

Marking interval Ln-1= |Pn-1-Pn| … … (2 c)

Fig. 7 to 9 show examples of the operation result of the mark interval.

Fig. 7 shows the result of the operation of the mark interval in the case where there is no mark deficiency. Fig. 8 shows the result of the operation of the mark interval when the mark defect occurs at 1. Fig. 9 shows the result of the operation of the mark interval when the mark defect is continuously generated.

Currently, it is assumed that a plurality of marks 45 are provided at intervals of 500mm in the length direction of the main rope 24 at the time of elevator installation. In this case, the reference value of the mark interval is set to 500mm. If each mark 45 on the main rope 24 is accurately detected by the sensor 28, the mark interval is calculated at approximately 500mm as shown in fig. 7.

Here, due to aging or the like, a state in which a part of each mark 45 cannot be detected by the sensor 28, that is, a mark defect may occur. As shown in fig. 8, if there is a 1-position mark defect, the mark interval corresponding to the defect position is approximately 2 times of 500mm. As shown in fig. 9, if there are 3 mark defects in succession, the mark interval corresponding to the defect portion becomes approximately 4 times of 500mm. Therefore, it is found that when the mark is missing, the mark interval becomes longer by an integer multiple of the reference value.

Since the rope moving distance is determined for each building, the expected number of mark detections for each rope can be obtained by dividing the rope moving distance by the reference value of the mark interval. By making this expected number likelihood, the expected range of the number of mark detections that can be obtained at the time of measurement can be determined as follows.

Small detection number < expected range < large detection number

In addition, the detection number is set to be smaller than the expected number of the above-mentioned mark detection in consideration of measurement errors and the like at the time of the mark detection. In consideration of measurement errors and the like at the time of detection of the marks, the number of detections is set to be slightly larger than the expected number of detection of the marks.

Hereinafter, the operation of the present system will be described in detail with reference to (a) a main flow, (b) a length measurement operation process, (c) a mark detection process, and (d) a mark interval calculation process.

(a) Main flow

Fig. 10 is a flowchart for explaining the main flow of the rope inspection system according to embodiment 1, and shows an overall flow for automatically measuring the intervals between the plurality of marks 45 attached to the main rope 24. The processing shown in the flowchart is mainly performed by the control panel 40.

In addition, since the main rope 24 is actually constituted by a plurality of ropes, the measurement process of the mark interval is performed for each rope. In the following, for the sake of simplicity of explanation, the process of measuring the mark interval for any one of the main ropes 24 will be described.

First, the control panel 40 sets, as an initial setting, various conditions related to measurement of the mark interval including, for example, a lifting range, an operation speed, and the like (step S101). For example, after the operation service for the elevator user is completed at night, the marking interval is measured. The control panel 40 moves the car 20 up and down at a predetermined speed by driving the hoisting machine 23, and thereby performs the length measuring operation while feeding the main rope 24 in one direction (step S102). By this length measurement operation process, the signal (voltage V) output from the sensor 28 and the integrated value (integrated pulse number) of the pulse signal output from the encoder 29 are stored in the memory 30a of the arithmetic device 30 at a predetermined period in accordance with the movement of the main rope 24. Details will be described later using fig. 11.

If the operation of the car 20 is temporarily stopped for some reason and the length measurement operation process is not normally ended (no in step S102), the control panel 40 updates the value of the retry counter RC (step S103). The retry counter RC is a counter for counting the number of retries of the length-measuring operation process, and is provided in the control panel 40. The various counters described later are also provided in the control panel 40.

The purpose of setting the retry counter RC is to avoid repeated execution of the length measurement operation process a plurality of times. A limit value is set in advance for the value (retry number) of the retry counter RC. If the value of the retry counter RC is within the preset limit (no at step S104), the control board 40 executes the length-measuring operation process again (step S200). If the value of the retry counter RC is outside the above-described limit (yes in step S104), the control board 40 sets a retry abnormality (step S105), and reports the retry abnormality to a predetermined report destination (step S109). The "predetermined report destination" includes the terminal device 52 held by the maintenance person, the remote monitoring center 51, and the like.

When the length measurement operation process is normally ended (yes in step S102), the control panel 40 executes the mark detection process by the arithmetic device 30 (step S300). In this mark detection process, the position of each mark 45 attached to the main rope 24 and the number of marks 45 (mark detection number) are obtained using the signal (voltage V) output from the sensor 28 and data (accumulated pulse number) indicating the lifting position of the car 20. Details will be described later using fig. 12.

When the number of detected marks is abnormal (no in step S106), the control panel 40 invalidates the measurement result (mark detection position) and terminates the mark interval calculation processing. At this time, the control panel 40 reports the abnormality of the number of detected marks to the predetermined report destination (step S109).

When the number of mark detections is normal (yes in step S106), the control panel 40 performs a mark interval arithmetic process (step S400). In this mark interval calculation process, a mark interval is calculated based on the mark position detected in step S300. Details will be described later with reference to fig. 13 and 14.

In the above-described marking interval calculation processing in step S400, when the content of the normal marking interval is set (yes in step S107), the control panel 40 validates the measurement result of the marking interval, and determines the rope elongation based on the measurement result. At this time, the control panel 40 reports that the measurement has been performed normally to the predetermined report destination (step S108). On the other hand, when there is an abnormality in the mark interval (no in step S107), the control panel 40 invalidates the measurement result of the mark interval, and reports the abnormality in the mark interval to the predetermined report destination (step S109).

(b) Length measurement operation processing

Fig. 11 is a flowchart for explaining the length measurement operation process performed in step S200 of fig. 10.

The control panel 40 sets, as initial settings, various conditions related to the length measurement operation processing including, for example, a length measurement start position, a length measurement end position, and the like (step S201). After the control panel 40 moves the car 20 to the length measurement start position (for example, the lowest floor), the control panel instructs the arithmetic device 30 to start the length measurement operation (step S202).

When the car 20 moves from the length measurement start position at a predetermined operation speed, a pulse signal is output from the encoder 29 and is applied to the arithmetic device 30 via the control panel 40. Further, a voltage signal corresponding to the surface reflection of the main rope 24 is output from the sensor 28. The voltage signal is applied as digital data to the arithmetic device 30 via an a/D converter (not shown).

In the length measurement operation, the arithmetic device 30 calculates the number of accumulated pulses of the encoder 29 corresponding to the up-down position of the car 20, and stores the number of accumulated pulses in the memory 30a together with the output voltage V (digital data) of the sensor 28 at a predetermined period (step S203). If the car 20 does not reach the length measurement end position (for example, the uppermost floor) (no in step S204), the control panel 40 performs a predetermined standby process (step S205).

When the car 20 reaches the length measurement end position and the length measurement operation process ends normally (yes in step S206), the control panel 40 ends the length measurement operation process after the normal end setting is made (step S207). On the other hand, if the length measurement operation process has not ended normally for some reason (no in step S206), the control panel 40 ends the length measurement operation process after the abnormal end setting is made (step S208).

As described in fig. 10, when the length measurement operation process is not normally ended, the length measurement operation process is executed again within a predetermined limit. When the length measurement operation process is normally ended, a mark detection process described later is executed.

(c) Marker detection process

Fig. 12 is a flowchart for explaining the mark detection process performed in step S300 of fig. 10.

The control panel 40 sets, as an initial setting, various conditions related to the mark detection process, such as an expected range of the mark detection number relative to the lifting range (step S301). The label detection process is performed by the arithmetic device 30 under the control of the control panel 40.

The arithmetic device 30 compares the output voltage V of the sensor 28 stored in the memory 30a at a predetermined period with a preset threshold voltage Vs, thereby detecting the position of the mark 45 attached to the main rope 24. Specifically, the arithmetic device 30 obtains the rising time or the arrangement index of the voltage signal when the output voltage V exceeds the threshold voltage Vs, and extracts the accumulated number of pulses of the encoder 29 corresponding to the rising time or the arrangement index from the memory 30 a. Then, the arithmetic device 30 obtains the up-down position obtained by multiplying the accumulated pulse number by the pulse rate as the position of the marker 45, and stores the position in the memory 30a (step S302).

The arithmetic device 30 updates the mark detection number every time the position of the mark 45 is detected, and stores the mark detection number in the memory 30a (step S303). The arithmetic device 30 repeatedly performs the above-described calculation of the mark position and the update of the mark detection number until the data to be detected ends (no in step S304).

After the data is completed, the control panel 40 acquires the number of mark detections from the arithmetic unit 30, and determines whether the number of mark detections is within a predetermined expected range (step S305). If each of the markers 45 on the main rope 24 can be detected, the number of marker detections is within the expected range. However, for example, when a part of each mark 45 cannot be detected due to aging or the like, or when false detection occurs due to the influence of noise, the mark detection number is out of the expected range.

If the number of mark detections is within the expected range (yes in step S305), the control panel 40 ends the mark detection process after setting the number of mark detections to be normal (step S306). On the other hand, when the number of detected marks is smaller than the expected range (yes in step S307), the control panel 40 sets an abnormality whose number of detected marks is smaller (step S308), and then ends the mark detection process. If the number of detected marks is greater than the expected range (no in step S307), the control panel 40 sets an abnormality having a greater number of detected marks (step S309), and then ends the mark detection process.

In fig. 12, the order of determining the number of mark detections is described after the end of the data, but for example, when the number of mark detections is updated, at least whether the number of mark detections is greater than the expected range of mark detections may be determined, and if the number of mark detections is greater than the expected range of mark detections, the mark detection process may be ended after the abnormality setting is performed. This can suppress the capacity of the memory 30a storing the marker positions and unnecessary processing time. The mark detection process is preferably performed for each sensor 28 used for each rope constituting the main rope 24.

By determining the number of detected marks in this way, it is possible to perform at least the mark interval arithmetic processing described later on the main rope 24 whose number of detected marks is within the expected range. On the other hand, regarding the main rope 24 whose number of detected marks is out of the expected range, it is possible to consider a decrease in reflectivity of the marks 45, dust in the hoistway, adhesion of concrete powder in the hoistway, and the like. Thus, by performing abnormality reporting, countermeasures such as detailed inspection of the main rope 24 and cleaning instructions can be taken.

(d) Marking interval arithmetic processing

Fig. 13 and 14 are flowcharts for explaining the mark interval arithmetic processing executed in step S400 of fig. 10.

The control panel 40 sets, for example, a reference value, an allowable range, and the like of the mark interval as an initial setting, and initializes various counters MC1 to MC4 related to the mark interval (step S401).

The mark interval arithmetic processing is performed by the arithmetic device 30 under the control of the control panel 40. The arithmetic device 30 calculates a mark interval based on the position of each mark 45 obtained by the mark detection process (step S402). The control panel 40 reads the data of the mark interval calculated by the arithmetic device 30, and performs the following determination processing.

That is, first, the control panel 40 determines whether or not the mark interval read from the arithmetic device 30 is within a predetermined normal range with respect to the reference value (step S403). If the mark interval is within the normal range (yes at step S403), the control board 40 determines the mark interval as valid and updates the value of the mark interval normal counter MC1 (step S404).

For example, if noise equal to or higher than the threshold voltage Vs is included in the output voltage V of the sensor 28, the position of the mark 45 may be erroneously detected due to the influence of the noise, and the mark interval may be shorter than the normal range. Accordingly, when the mark interval read from the arithmetic device 30 is shorter than the normal range (yes in step S405), the control panel 40 invalidates the mark interval and updates the value of the mark interval small counter MC2 (step S406).

If a mark defect occurs in a state where a part of each mark 45 cannot be detected, the mark interval becomes longer than the normal range. In general, the measurement process of the mark interval is stopped when there is a mark deficiency, but in the present embodiment, the allowable range Ltemp is newly determined for recovery at the time of the mark deficiency, thereby realizing continuation of the measurement process of the mark interval. As will be described later, the allowable range Ltemp is set focusing on the case where the mark deficiency occurs as an integer multiple of the reference value.

If the mark interval read from the arithmetic device 30 is within the allowable range Ltemp (yes in step S407), the control panel 40 determines that the mark interval is valid, and updates the value of the mark shortage counter MC3 (step S408). On the other hand, if the mark interval read from the arithmetic device 30 is outside the allowable range Ltemp (no in step S407), the control panel 40 determines that the mark interval is invalid, and updates the value of the mark interval large counter MC4 (step S409).

Here, the allowable range Ltemp will be described in detail.

The mark interval is obtained based on the mark position by the above equations (2 a) to (2 c). The mark intervals are displayed on the display device 31, and are sequentially stored in the memory 30a in the arithmetic device 30 in an arrangement as shown in fig. 7. The control panel 40 determines whether the mark interval is within the allowable range Ltemp determined as follows.

Allowed range Ltemp

The reference value of the mark interval is set to Lb. When the allowable value of the shortening-side mark interval with respect to the reference value Lb is Δm and the allowable value of the extension-side mark interval is Δp, the allowable range Ltemp is represented by the following formula (3).

M×(Lb-Δm)<Ltemp<M×(Lb+Δp)……(3)

Wherein, 1.ltoreq.M.ltoreq.Mmax, M is a positive integer, mmax is a predetermined maximum value.

That is, the allowable range Ltemp is defined by M times the reference value Lb (for example, 500 mm) of the mark interval. The lower limit value of the allowable range Ltemp is a value M times the value obtained by subtracting the 1 st allowable value Δm from the reference value Lb. The upper limit value of the allowable range Ltemp is a value M times the value obtained by adding the 2 nd allowable value Δp to the reference value Lb.

The allowable values Δm and Δp may be the same or different values, and are arbitrarily set within the range of measurement errors. The minimum value of M is 1, and the maximum value (Mmax) of M is 5-10. The maximum value Mmax is determined based on the relationship between the rope travel distance and the floor space so that the mark space when the mark is missing is within 1 floor amount.

For example, in the case of the main rope 24 provided in a building having a lifting stroke of 100m, if it is 2 as shown in fig. 1: 1, the distance of travel of the main rope 24 is 200m. The floor space of the building to which the main rope 24 is applied is generally about 4 m. Considering the movement distance 200m of the main rope 24, if the mark is missing of about 4m of 1 floor amount, it is considered that the measurement process of the mark interval is not particularly hindered even if the continuously detectable position of the mark 45 other than the mark missing is used and the measurement process is continued.

In addition, in terms of strength management of the main rope 24, the time when the elongation of the rope in fig. 5 becomes λ is set as the replacement time, whereby safety can be obtained. Therefore, the allowable value Δp of the extension-side mark interval is preferably obtained by the following equation (4). In the initial setting (step 401), the allowable value Δp of the extension-side mark interval and the allowable value Δm of the shortening-side mark interval may be obtained in advance as Mmax data tables.

M×Lb×λ……(4)

In general, since the replacement work is required to be performed by an operator before the replacement time is reached, and the schedule adjustment during the rope deployment period is considered, the coefficient smaller than the elongation λ may be determined as the coefficient α for observation, and the rope elongation may be managed based on λ and α.

If the main rope 24 is not stretched, the distance between the marks calculated by the arithmetic unit 30 is the same as the mark interval (for example, 500 mm) attached to the main rope 24 at the time of installation. When the main rope 24 is elongated due to aging, the distance between the marks calculated by the arithmetic device 30 becomes longer than the mark interval (for example, 500 mm) at the time of installation.

Here, the marks 45 are arranged at equal intervals in the longitudinal direction of the main rope 24 when the elevator is installed. Therefore, when the main rope 24 is not stretched due to degradation, the count value of the pulse signal is substantially the same as the reference value corresponding to the mark interval at the time of installation. On the other hand, when the main rope 24 is elongated due to degradation, the count value of the pulse signal exceeds the reference value corresponding to the mark interval at the time of attachment (see fig. 4).

After the judgment processing of the mark interval, if the data of the mark position to be judged remains (no in step S410), the processing from the calculation of the mark interval to the judgment is repeated (steps S402 to S409). When the processing for all the data ends (yes at step S410), the control panel 40 checks the value of the mark interval small counter MC2 and the value of the mark interval large counter M4 (step S411). If the initial values of the counters MC2 and M4 are kept unchanged (yes in step S411), the control panel 40 ends the mark interval calculation processing after setting the measurement result of the mark interval to be normal (step S412).

On the other hand, if neither of the counters MC2 and MC4 is the initial value (no in step S411), the control panel 40 ends the marker interval calculation process after setting the content of the abnormality in the measurement result of the marker interval (step S413).

When the mark interval calculation process is completed, the calculation device 30 calculates the elongation of the main rope 24 based on the distance of each mark interval stored in the memory 30a as the measurement result, and displays the result on the display device 31. In this case, if the mark defect occurs within the allowable range Ltemp, the measurement accuracy of the elongation can be improved if the elongation is calculated based on the distance between the marks except for the mark defect portion. The mark missing portion (L22 in the example of fig. 8 and L23 in the example of fig. 9) can be determined based on the timing at which the mark missing counter MC3 is updated.

Further, the elongation may be displayed on the display device 31 only at the mark interval instead of being calculated by the arithmetic device 30. In this case, based on the measurement result of the mark interval, normal reporting is performed in step S108 in fig. 10, and abnormal reporting is performed in step S109 in fig. 10. In the case of abnormality report, it is also possible to specifically notify at which position the mark interval is abnormal. The abnormal portion of the mark interval can be determined from the timing at which the mark interval small counter MC2 is updated and the timing at which the mark interval large counter MC4 is updated.

For example, when the marking interval exceeds the reference value, a warning message may be displayed on the display device 31 or an alarm sound may be given to notify the maintenance personnel of the approaching rope replacement time. A warning message may be sent from the control panel 40 to the terminal device 52 held by the maintenance person. This can reduce the number of inspection operations performed by maintenance personnel, and can grasp the timing when the rope replacement is required and handle the inspection operations.

Further, if the measurement result of the marking interval is periodically transmitted to the remote monitoring center 51, the degradation state of the main rope 24 of each building can be centrally managed on the monitoring center 51 side, and the maintenance person can be notified of the building whose rope replacement timing is approaching.

In the above embodiment, the reference value of the mark interval is Lb and the mark interval and the mark shortage compensation are basically calculated using two mark intervals, but the moving average may be basically calculated using 2 or more predetermined mark intervals and the mark shortage compensation and the mark interval may be calculated. This can prevent measurement errors and improve the measurement accuracy of the mark space.

In the above embodiment, the mark detection process (step S300) and the mark interval calculation process (step S400) are performed after the length measurement operation process (step S200), but a series of processes may be performed in units of data blocks stored in the memory 30a so as to face the predetermined elevation range. This can suppress the capacity of the memory 30a actually mounted in the computing device 30.

In addition, the mark detection process may be configured to, for example: the output voltage V of the sensor 28 is compared with the threshold voltage Vs for marker detection by using a comparator, the rise of the output of the comparator is triggered, the cumulative number of pulses of the encoder 29 is stored in the memory 30a, and the rise and fall position is obtained from the cumulative number of pulses to be the marker position. Thus, the output voltage V of the sensor 28 and the accumulated pulse from the encoder 29 do not need to be stored for a predetermined period, and the load of the arithmetic device 30 can be reduced to perform high-speed processing, and the capacity of the memory 30a can be further suppressed.

As described above, according to embodiment 1, even when a mark defect occurs due to aging of a rope or the like, measurement of a mark interval can be continued within a predetermined allowable range, and a high-precision measurement result can be obtained. Further, even if a plurality of sensors 28 are not disposed around the rope, it is possible to cope with the mark shortage, and it is possible to suppress an increase in cost.

(embodiment 2)

Next, embodiment 2 will be described.

In embodiment 1, when the number of detected marks obtained by the mark detection process is out of the predetermined expected range, the process is terminated by determining that the number is abnormal (see steps S308 and S309 in fig. 12). In contrast, in embodiment 2, when the number of detected marks is out of the predetermined expected range, the threshold voltage Vs is finely adjusted and the mark detection process is performed again.

Fig. 15 and 16 are diagrams for explaining the threshold voltage adjustment method according to embodiment 2, in which fig. 15 shows the threshold voltage adjustment method when the number of mark detections is small, and fig. 16 shows the threshold voltage adjustment method when the number of mark detections is large.

As shown in fig. 15, when the number of detected marks is smaller than the expected range, the threshold voltage Vs for mark detection is reduced by a predetermined voltage value and adjusted to a new threshold voltage Vs1. When the number of detected marks is larger than the expected range, the threshold voltage Vs for mark detection is increased by a predetermined voltage value and adjusted to a new threshold voltage Vs1.

Fig. 17 and 18 are flowcharts for explaining the mark detection process according to embodiment 2. This mark detection process is performed instead of step S300 of fig. 10 (step S500). Note that, since the main flow (fig. 10), the length measurement operation process (fig. 11), and the mark interval calculation process (fig. 13) are the same as those of embodiment 1, the description thereof is omitted here.

The control panel 40 sets, as an initial setting, various conditions related to the mark detection process, such as an adjustment range of the threshold voltage Vs and the threshold voltage change counter VC, in addition to the expected range of the mark detection number relative to the lifting range (step S501). The label detection process is performed by the arithmetic device 30 under the control of the control panel 40.

Here, in the mark detection processing of embodiment 2, the processing of steps S502 to S506 in fig. 17 is the same as the processing of steps S302 to S306 in fig. 12. That is, the arithmetic device 30 compares the output voltage V of the sensor 28 stored in the memory 30a at a predetermined period with the threshold voltage Vs, thereby detecting the position of the mark 45 attached to the main rope 24 and storing the detected position in the memory 30a (step S502). The arithmetic device 30 also updates the mark detection number every time the position of the mark 45 is detected (step S503). The arithmetic device 30 repeatedly performs the above-described calculation of the marker position and the update of the marker detection number until the data to be detected ends (step S504).

After the data is completed, the control panel 40 acquires the number of mark detections from the arithmetic unit 30, and determines whether the number of mark detections is within a predetermined expected range (step S505). As a result, if the number of mark detections is within the expected range (yes in step S505), the control panel 40 sets the normal state information indicating that the number of mark detections is appropriate.

Here, in embodiment 2, when the number of detected marks is out of the expected range, the control panel 40 fine-adjusts the threshold voltage Vs of the mark detection currently set in the computing device 30 (step S507). The "fine adjustment of the threshold voltage Vs" refers to adjustment in which the threshold voltage Vs is increased or decreased stepwise by a constant voltage unit.

Specifically, when the number of detected marks is smaller than the expected range (when the number of detected marks is smaller), the control panel 40 decreases the threshold voltage Vs by a predetermined voltage value and adjusts the threshold voltage to a new threshold voltage Vs1 (see fig. 15). When the number of mark detections is larger than the expected range (when the number of marks is larger), the control panel 40 increases the threshold voltage Vs by a predetermined voltage value to adjust the threshold voltage to a new threshold voltage Vs1 (see fig. 16).

In this way, when the threshold voltage Vs is trimmed to the new threshold voltage Vs1, the control panel 40 determines whether the threshold voltage Vs1 is within the predetermined adjustment range (step S508). When the threshold voltage Vs1 is out of the adjustment range (no in step S508), the control panel 40 sets an abnormality related to the adjustment process of the threshold voltage (step S509), and then ends the flag detection process.

On the other hand, when the threshold voltage Vs1 is within the adjustment range (yes in step S508), the control panel 40 updates the threshold voltage change counter VC (step S511) after the number of mark detections is restored to the initial value (step S510), and sets a new threshold voltage Vs1 in the arithmetic device 30 (step S512).

At this time, the control panel 40 determines whether or not the value of the threshold voltage change counter VC is within a predetermined limit range (step S513). If the value of the threshold voltage change counter VC is within the limit range (yes in step S513), the control board 40 causes the arithmetic device 30 to execute the flag detection process using the new threshold voltage Vs1 (step S502). On the other hand, if the value of the threshold voltage change counter VC is outside the limit range (no in step S513), the control panel 40 ends the flag detection process after setting the abnormality of the flag detection number (step S514).

As described above, according to embodiment 2, when the number of detected marks is out of the predetermined range of the number of detected marks during the mark detection process, the threshold voltage Vs is finely adjusted. In this way, the detection accuracy of the sensor 28 based on the individual difference can be adjusted, and the mark detection process can be performed again using the accumulated number of pulses and the output voltage V already stored in the memory 30a, even if the car 20 is not operated again.

(embodiment 3)

Embodiment 3 will be described below.

In embodiment 3, the threshold voltage Vs is substantially adjusted before the fine adjustment of the threshold voltage Vs described in embodiment 2. The "rough adjustment of the threshold voltage Vs" means that the threshold voltage Vs is not adjusted in a stepwise manner but adjusted to a value determined to some extent.

Fig. 19 and 20 are flowcharts for explaining the mark detection process according to embodiment 3. This mark detection process is performed instead of step S300 of fig. 10 (step S500). Note that, since the main flow (fig. 10), the length measurement operation process (fig. 11), and the mark interval calculation process (fig. 13) are the same as those of embodiment 1, the description thereof is omitted here. The same step numbers are given to the processes repeated as in embodiment 2, and the description thereof is omitted.

The control panel 40 sets, as an initial setting, various conditions related to the mark detection process, such as an adjustment range of the threshold voltage Vs and the threshold voltage change counter VC, in addition to the expected range of the mark detection number relative to the lifting range (step S501).

In the mark detection process according to embodiment 3, first, the threshold voltage adjustment process is performed as shown in fig. 20 (step S600).

That is, the control panel 40 calculates an average value Va of the output voltages V stored in the memory 30a at regular intervals (step S601). The control panel 40 determines whether the average value Va of the output voltage V is within a predetermined allowable range of voltage variation (step S602). If the average value Va of the output voltage V is within the allowable range of the voltage change (yes in step S602), the control panel 40 sets the threshold voltage (threshold voltage Vs at the time of initial setting) to be normal (step S606), and ends the threshold voltage adjustment process.

On the other hand, if the average value Va of the output voltage V is outside the allowable range of the voltage variation (no in step S602), the control panel 40 adjusts the threshold voltage Vs substantially as follows (step S603).

Rough adjustment of threshold voltage Vs

The average value Va of the output voltage V contains the voltage of the length of the mark 45 on the main rope 24. It is desirable to calculate the average value Va of the output voltage V in a range excluding the voltage of the length of the mark 45. However, the length of the applied mark 45 is small with respect to the mark interval, and even if the ratio of the output voltage V of the sensor 28 of the mark 45 to the outer peripheral surface 44a shown in fig. 3 is considered, the voltage by the length of the mark 45 can be substantially ignored.

Here, when Vp is the peak voltage (voltage corresponding to the portion indicated by the reference numeral 45) included in the output voltage V shown in fig. 15, vpa is the average value of the peak voltages Vp, and k is the adjustment coefficient of the threshold voltage, a new threshold voltage Vs1 is obtained by the following equation (5).

Vs1＝Va+k×(Vpa-Va)/2……(5)

In the case where the calculation of the peak voltage Vp is difficult, the new threshold voltage Vs1 may be obtained by multiplying the average value Vpa of the output voltage V by the adjustment coefficient k as shown in equation (6).

Vs1＝k×Vpa……(6)

In this case, the threshold voltage Vs1 is calculated using the average value Vpa of the peak voltage Vp or the average value Va of the output voltage V, but the threshold voltage Vs1 may be calculated using, for example, the median value of the peak voltage Vp or the median value of the output voltage V, taking into consideration the variance value of the peak voltage Vp and the output voltage V.

When the new threshold voltage Vs1 is obtained by such rough adjustment, the control panel 40 determines whether or not the threshold voltage Vs1 is within the predetermined threshold voltage change range (step S604). If the threshold voltage Vs1 is within the voltage change range (yes in step S604), the control panel 40 updates the threshold voltage Vs to the threshold voltage Vs1 (step S605), sets the threshold voltage (updated threshold voltage Vs 1) to be normal (step S606), and ends the threshold voltage adjustment process.

On the other hand, if the threshold voltage Vs1 is outside the voltage change range (no in step S604), the control panel 40 sets the threshold voltage (updated threshold voltage Vs 1) to be abnormal (step S607), and ends the threshold voltage adjustment process.

Returning to fig. 19, if the threshold voltage is set to be normal (no in step S601), the processing of steps S502 to S507 is performed. The processing in steps S502 to S507 is already described in embodiment 2, and therefore omitted here.

As described above, according to embodiment 3, by adjusting the threshold voltage Vs necessary for the mark detection in advance using the average value, the median value, or the like of the output voltage V, the number of times of fine adjustment of the threshold voltage when the number of mark detections is excessively large or small relative to the lifting range can be suppressed.

According to at least one embodiment described above, it is possible to provide a rope inspection system for an elevator, which can continue measurement of a mark interval even when a mark defect occurs, and can determine rope elongation based on the measurement result thereof to perform reliable strength management.

In addition, although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other modes, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the scope equivalent thereto.

Claims (9)

1. A rope inspection system for an elevator, which comprises a rope having a structure in which a car and a counterweight are suspended via a traction sheave of a hoisting machine and a surface of which is coated with resin, and which measures the intervals of a plurality of marks provided at regular intervals on the surface of the rope, characterized by comprising:

a sensor disposed in the vicinity of the rope;

a mark detection processing unit that detects a position of each of the marks based on a signal output from the sensor and data indicating a lifting position of the car as the rope moves;

a mark interval calculation processing unit configured to calculate a mark interval based on the position of each of the marks detected by the mark detection processing unit; and

a control device having a reference value for the marking interval of the rope, wherein when the marking interval obtained by the marking interval calculation processing unit as a measurement result is within an allowable range defined by an integer multiple of 2 or more of the reference value, the control device validates the measurement result, determines rope elongation based on the measurement result,

the maximum value of the integer multiple is determined based on a relationship between the moving distance of the rope and the floor space so that the mark space when the mark is missing is within 1 floor amount.

2. A rope inspection system for an elevator according to claim 1, characterized in that,

the lower limit value of the allowable range is the value of the integral multiple of the value obtained by subtracting the 1 st allowable value from the reference value,

the upper limit value of the allowable range is the value of the integral multiple of the value obtained by adding the 2 nd allowable value to the reference value.

3. A rope inspection system for an elevator according to claim 1, characterized in that,

the control device is configured to report an abnormality when the mark interval is out of the allowable range.

4. A rope inspection system for an elevator according to claim 1, characterized in that,

the control device is configured to have an expected number of mark detections obtained from a relation between the moving distance of the rope and the reference value, and to cause the mark interval calculation processing unit to perform a mark interval calculation process when the number of each mark obtained by the mark detection processing unit is within an expected range in which the expected number is likely to be.

5. The rope inspection system of an elevator as claimed in claim 4, characterized in that,

the control device is configured to report an abnormality when the number of the marks is out of the expected range.

6. The rope inspection system of an elevator as claimed in claim 5, characterized in that,

the control device is configured to fine-tune a threshold value of a signal level for the sensor within a predetermined allowable range when the number of the marks is out of the expected range.

7. The rope inspection system of an elevator as claimed in claim 6, characterized in that,

the control device is configured to adjust the threshold value approximately based on an average value or a median value of the signal levels of the sensors before trimming the threshold value.

8. The rope inspection system of an elevator as claimed in claim 6, characterized in that,

the control device is configured to adjust the threshold value approximately based on an average value or a median value of peaks included in the signal level of the sensor before fine-tuning the threshold value.

9. A rope inspection system for an elevator according to claim 1, characterized in that,

the elevator car is provided with a storage device which stores signals output from the sensor and data representing the lifting position of the elevator car at least at a certain period.