A method for monitoring the slippage of the elevator brake steel cable

Abstract

A method for monitoring the slippage of an elevator brake cable comprises the following steps: S1: uniformly marking the initial position around a pulley, denoted as a mark group A, with the outermost arc length between each mark being N; S2: selecting a cable on the pulley and uniformly marking it, denoted as a mark group Ba, with a mark interval of N; copying the marks of the mark group Ba to other cables on the same pulley so that each cable has a mark group; S3: aligning the mark positions of all cables on the same pulley so that each element of each cable mark group is in the same cross section according to the sequence number; S4: identifying based on an image whether an element in the mark group A is in the same cross section as an element with a corresponding sequence number in the cable mark group Ba; if so, there is an intersection between the elements with the corresponding sequence number in the mark group A and the mark group Ba, and it is determined that the cable has not slipped; otherwise, slippage has occurred. The present invention can timely and accurately monitor whether the cable is slipping, and has a simple structure, low cost, and high safety.

Description

Technical Field

[0001] The present invention relates to the technical field of elevator fault monitoring, in particular to a method for monitoring the slippage of an elevator brake cable. Background Art

[0002] The working principle of existing elevators is as follows: the elevator's rise and fall depends on a steel cable, which connects to the car and then passes around a pulley block. The steel cable just fits on the pulley's grooves, and multiple steel cables can be wrapped around one pulley. The pulley block usually includes a drive wheel and a guide wheel, and some pulley blocks only have multiple drive wheels. The drive wheel is controlled by an electric motor to rotate. The other end of the steel cable is also connected to a counterweight to offset the weight of the car and keep the two as balanced as possible. When the motor controls the drive wheel to rotate in one direction, the elevator will rise, and when it rotates in the other direction, the elevator will descend. Existing elevators are usually not pulled by a single steel cable, but by multiple common steel cables. Due to the frequent sliding friction between the steel cable and the drive wheel, if the elevator slips, it will affect the elevator brake and damage the steel cable and pulley, not only reducing the lifespan but also posing a safety hazard.

[0003] CN 207608170U discloses an elevator main unit with an anti-wire rope slippage detection and protection function, which records that "a driving sheave and a guide pulley are connected by a wire rope, and a sensor is provided on the wire rope. The sensing signal of the sensor is sent to a wire rope movement detection device, and the wire rope movement detection device sends the received movement signal to a control cabinet; when the elevator is running, the moving speed of the wire rope is detected to determine whether the elevator is slipping. If the slippage speed exceeds the set value, the main unit is stopped. When the elevator wire rope is detected to be broken or slipping during operation, the infrared light sensor detects the broken wire rope and slipping, the sound and light alarm sounds an alarm, the elevator stops running, and the safety circuit is disconnected for protection."

[0004] It can be seen that the above-mentioned prior art determines whether the elevator is slipping by detecting the moving speed of the wire rope. However, this method has the following disadvantages: (1) If it relies on detecting speed changes for monitoring, it is impossible to accurately determine whether the elevator has hidden dangers in some cases. For example, the elevator is not pulled by a single wire rope, but by multiple wire ropes. This method of monitoring by relying on speed changes makes it difficult to detect whether one or several wire ropes have abnormalities. For example, if the wire rope is cracked or slipped, a single wire rope will not affect the overall running speed, so the elevator will still run normally. However, this phenomenon will pose a safety hazard and the detection efficiency is low; (2) Since there are multiple wire ropes, a speed detection sensor needs to be set on each wire rope, which makes the structure complicated and increases the cost. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for monitoring the slippage of an elevator brake cable.

[0006] The technical solution of the present invention is: a method for monitoring the slippage of an elevator brake cable, comprising the following steps:

[0007] S1: Mark the initial positions evenly around the elevator pulley, denoted as mark group A. Each mark is denoted as {a1, a2, a3...an}, and the outermost arc length between each mark is N;

[0008] S2: Select a steel cable on the pulley and mark it evenly, which is called a mark group Ba. Each mark is denoted as {ba1, ba2, ba3...ban}, and the mark interval is N. The marks of the mark group Ba are copied to the other steel cables on the same pulley so that each steel cable has a mark group.

[0009] S3: Align the marking positions of all cables on the same pulley so that each element of each cable marking group is in the same cross section according to the serial number;

[0010] S4: Identify based on the image whether the elements in the pulley mark group A are in the same cross section as the elements with corresponding serial numbers in the steel cable mark group Ba. If so, there is an intersection between the elements with corresponding serial numbers in the mark group A and the mark group Ba. At this time, it is determined that the steel cable has not slipped; otherwise, slippage has occurred.

[0011] Furthermore, it also includes:

[0012] S5: Determine whether the steel cable mark group Ba and the corresponding elements in other steel cable mark groups on the pulley are in the same cross section. If so, there is a transverse intersection between the steel cable mark group Ba and the corresponding elements in other steel cable mark groups. In this case, it is determined that the brake cable is not slipping; otherwise, slipping occurs.

[0013] S6: As long as any of the slippage phenomena in steps S4 and S5 is detected, it is finally determined that the brake cable is slipping and a prompt is given.

[0014] Furthermore, in S4, the camera is used to capture the marks at the connection between the brake and the steel cable, and a visual image algorithm is used to determine whether there are intersections between the steel cable and the pulley and between the corresponding elements of each steel cable.

[0015] Furthermore, in S1, the method for determining the outermost arc length N includes: measuring the circumference of the pulley by a measuring tool, and then evenly dividing the circumference into several parts so that there is at least one mark, and the arc length between the marks is recorded as N; when there is only one mark, N is the circumference of the brake wheel.

[0016] Furthermore, each mark of the mark group is recorded on the steel cable and the pulley by spraying.

[0017] Furthermore, when the motor controls the pulley to rotate, the steel cable will move with the pulley. When the marks on the steel cable pass through the pulley at regular intervals, they will correspond one-to-one with the marks on the pulley. Once a displacement difference is detected between the corresponding marks, it is determined that a certain steel cable is slipping or faulty.

[0018] Beneficial effects of the present invention:

[0019] (1) More timely and accurate recognition efficiency: By using image vision to monitor the displacement changes between the steel cables and the pulleys of the same pulley, the recognition efficiency is faster and more accurate compared to the existing method of judging slippage by detecting speed. This is because no matter whether the steel cable is cracked or slipped, there will be displacement differences. Even if the elevator is running normally at this time, the displacement difference of the steel cable can be quickly detected. However, by detecting speed, sometimes the steel cable cracks and other conditions do not necessarily affect the speed, and the elevator can operate normally, so it is difficult to accurately detect the steel cable fault.

[0020] (2) Simple structure and low cost: The present invention uses a camera to shoot, and even if multiple steel cables are installed on a pulley, only one camera is needed; if the speed is detected, a speed sensor needs to be installed on each steel cable. If there are many steel cables, the cost and installation complexity will be greatly increased;

[0021] (3) Double protection: The present invention includes two positioning verifications, one is the correspondence between the pulley and a steel cable, and the other is the correspondence between multiple steel cables. Once any slippage is detected, it can be determined that a certain steel cable has slipped, thereby achieving double protection and being able to quickly detect which steel cable has slipped. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 : is a schematic diagram of the markings of the pulley in an embodiment of the present invention (“-” is a mark);

[0023] Figure 2 Schematic diagram of alignment of marks between pulleys and steel cables, and between steel cables (“-” indicates a mark) in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] like Figure 1 and Figure 2 A method for monitoring the slippage of an elevator brake cable is shown, comprising the following steps:

[0026] S101: Mark the initial position evenly around the pulley 1 of the brake, which is recorded as a mark group A. Each mark is recorded as {a1, a2, a3...an}, and the outermost arc length between each mark is N.

[0027] Specifically, pulley 1 in this embodiment is the drive wheel of an elevator. Its rotation is controlled by a motor, driving the steel cable attached to it. The outermost arc length N between each mark is determined by measuring the circumference of the brake wheel using a measuring tool such as a tape measure. This circumference is then evenly divided into a number of sections (the larger the circumference, the more sections are used, and there is no limit to the number of sections), ensuring that at least one mark is present. The arc length between each mark is recorded as N (if only one mark is present, N is the circumference of the brake wheel).

[0028] The marking method of this embodiment preferably adopts the spraying method, and the mark is sprayed onto the pulley 1. Figure 1 As shown, n=8, and each tag in tag group A is denoted as {a1, a2, a3...a8}.

[0029] It is understandable that when there are multiple pulleys, each pulley and the steel cable of the pulley can be marked, or at least one pulley among the multiple pulleys and the steel cable thereon can be marked, while the other pulleys may not be marked.

[0030] S102: Select a steel cable 2 on pulley 1, mark the steel cable 2 evenly, record it as a mark group Ba, each mark is recorded as {ba1, ba2, ba3...ban}, and the mark interval is N; copy the marks of the mark group Ba to other steel cables 2 on the same pulley, so that each steel cable has a mark group.

[0031] Specifically, there are multiple steel cables wrapped around a pulley. First, select one of the steel cables, such as the one closest to the outermost side of the pulley.

[0032] That cable is marked with an arc length N on the pulley as the marking interval. After marking one cable, the markings of the marking group Ba are copied to the other cables on the same pulley, so that each cable has a marking. These markings are recorded as marking groups Bb, Bc, Bd...Bn. For example:

[0033] The marking group corresponding to the first steel cable: Ba={ba1,ba2,ba3......ban};

[0034] The marking group corresponding to the second steel cable: Bb={bb1,bb2,bb3......bbn};

[0035] The marking group corresponding to the third steel cable: Bc={bc1,bc2,bc3......bcn};

[0036] The marking group corresponding to the fourth steel cable: Bd={bd1,bd2,bd3......bdn}; ......;

[0038] The marking group corresponding to the Nth steel cable: Bn={bn1,bn2,bn3......bnn}.

[0039] S103: Align the marking positions of all the steel cables on the same pulley so that each element of the marking group is in the same position according to the sequence number.

[0040] A cross section.

[0041] Specifically, align the first steel cable with the mark of pulley 1 one by one according to the serial number, and then align the other steel cables of the same pulley with the mark of the steel cable one by one according to the serial number. For example:

[0042] a1 and ba1 are in the same cross section, ..., an and ban are in the same cross section;

[0043] ba1, bb1, bc1, bd1...bn1 are in the same cross section;

[0044] ba2, bb2, bc2, bd2...bn2 are in the same cross section; ......;

[0046] ban, bbn, bcn, bdn...bnn are in the same cross section.

[0047] S104: Identify whether the elements in the pulley mark group A are in the same position as the elements with corresponding serial numbers in the cable mark group Ba according to the image.

[0048] In the same cross section, if yes, there is an intersection between the elements with corresponding serial numbers in the mark group A and the mark group Ba, then it is determined that the steel cable has not slipped; otherwise, slipping has occurred.

[0049] Specifically, the camera is installed at the junction of the pulley and the steel cable. As long as it can capture whether the steel cable mark on the pulley corresponds to the mark on the pulley, it can be identified and judged using a visual image algorithm. If the steel cable slips, the serial number of the mark group Ba will be misaligned with the serial number of the mark group A, and the serial numbers between the two will not correspond one to one, so the corresponding serial numbers will not intersect, and it is determined that the steel cable has slipped. For example: if an and ban are in the same cross-section, the an mark and the ban mark will have an intersection point, and at this time it is determined that the steel cable has not slipped; otherwise, slipping has occurred. Among them, the error range of the intersection can be specified by the actual maintenance personnel during use. The error range for elevators with high precision requirements is set to be small, otherwise the error range can be appropriately enlarged.

[0050] S105: Determine whether the corresponding elements of the cable mark group Ba and other cable mark groups on the pulley are in the same section

[0051] If yes, then there is a horizontal intersection between the steel cable mark group Ba and the corresponding elements in other steel cable mark groups. At this time, it is determined that the steel cable has not slipped; otherwise, slipping has occurred.

[0052] For example: if ban, bbn, bcn, bdn...bnn are in the same cross section, then the ban, bbn, bcn, bdn...bnn marks will have a horizontal intersection. At this time, it is determined that the steel cable has not slipped; otherwise, slippage has occurred.

[0053] S106: According to steps S104 and S105, as long as any slippage phenomenon is detected, it is finally determined that the brake cable is slipping and a prompt is issued.

[0054] The overall working principle of the present invention is as follows: the steel cable 2 is marked at intervals N, and the mark group between the steel cable 2 and the pulley 1 must satisfy the requirement that each time the steel cable passes through the pulley, the serial numbers of the marks on it correspond one-to-one with the serial numbers of the marks on the pulley; when the motor controls the pulley to rotate, the steel cable will move with the pulley, and its marks will also pass through the pulley and move out of the pulley, and so on. However, as long as the steel cable does not slip, the marks on the steel cable will correspond one-to-one with the corresponding serial numbers of the pulley each time it passes through the pulley. Once slippage occurs, misalignment will occur. Therefore, by photographing the marks between the pulley and the steel cable with a camera, it is possible to determine whether the serial numbers correspond one-to-one. Once it is detected that there is no intersection between the corresponding serial numbers, it is determined to be slipping. The monitoring platform can inform the operator that the elevator is in a slipping state, so that the operator can make timely repairs, thereby greatly improving the service life of the pulley, steel rope and motor, and greatly reducing safety hazards.

[0055] In summary, the present invention has the following advantages:

[0056] (1) More timely and accurate identification efficiency: By using image vision to monitor the displacement changes between the steel cables and the pulley of the same pulley, the identification efficiency is faster and more accurate compared to the existing method of judging slippage by detecting speed. Because no matter whether the steel cable is cracked or slipped, there will be displacement difference. Even if the elevator is running normally at this time, it can be quickly detected which steel cable has the displacement difference; and by detecting speed, sometimes a single steel cable or several steel cables have cracks, slippage, etc., which does not necessarily affect the speed and the normal operation of the elevator, so it is difficult to accurately detect the corresponding steel cable fault;

[0057] (2) Simple structure and low cost: The present invention uses a camera to shoot, and even if multiple steel cables are installed on a pulley, only one camera is needed; if the speed is detected, a speed sensor needs to be installed on each steel cable. If there are many steel cables, the cost and installation complexity will be greatly increased;

[0058] (3) Double protection: The present invention includes two positioning verifications, one is the correspondence between the pulley and a steel cable, and the other is the correspondence between multiple steel cables, that is, the mark of the outermost steel cable can be aligned and compared with the pulley mark, and the steel cable mark in the middle area is compared with the mark of the adjacent steel cable. Once any slip is detected, it can be determined that a certain steel cable has slipped, thereby achieving double protection and being able to quickly detect which steel cable has slipped; compared with comparing each steel cable with the pulley mark, the comparison method of the present invention can reduce the error caused by the downward or upward angle when the camera is shooting.

[0059] It should be noted that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the scope of protection of the present invention.

Claims

1. A method for monitoring the slippage of an elevator brake cable, characterized in that: The following steps are involved: S1: Mark the initial positions evenly around the elevator pulley, denoted as mark group A. Each mark is denoted as {a1, a2, a3...an}, and the outermost arc length between each mark is N; S2: Select a steel cable on the pulley and mark it evenly, which is called a mark group Ba. Each mark is denoted as {ba1, ba2, ba3...ban}, and the mark interval is N. The marks of the mark group Ba are copied to the other steel cables on the same pulley so that each steel cable has a mark group. S3: Align the marking positions of all cables on the same pulley so that each element of each cable marking group is in the same cross section according to the serial number; S4: Identify based on the image whether the elements in the pulley mark group A and the elements with corresponding serial numbers in the wire rope mark group Ba are in the same cross section. If so, there is an intersection between the elements with corresponding serial numbers in the mark group A and the mark group Ba, and it is determined that the wire rope has not slipped; otherwise, slipping has occurred. S5: Determine whether the steel cable mark group Ba and the corresponding elements in other steel cable mark groups on the pulley are in the same cross section. If so, there is a transverse intersection between the steel cable mark group Ba and the corresponding elements in other steel cable mark groups. In this case, it is determined that the brake cable is not slipping; otherwise, slipping occurs. S6: As long as any of the slippage phenomena in steps S4 and S5 is detected, it is finally determined that the brake cable is slipping and a prompt is given.

2. The method for monitoring elevator brake cable slippage according to claim 1, characterized in that: In S4, the camera is used to capture the marks at the connection between the brake and the steel cable, and the visual image algorithm is used to determine whether there are intersections between the corresponding elements between the steel cable and the pulley and between the steel cables.

3. The method for monitoring elevator brake cable slippage according to claim 1, characterized in that: In S1, the method for determining the outermost arc length N includes: measuring the circumference of the pulley using a measuring tool, then evenly dividing the circumference into several parts so that there is at least one mark, and the arc length between the marks is recorded as N; when there is only one mark, N is the circumference of the brake pulley.

4. The method for monitoring elevator brake cable slippage according to claim 1, characterized in that: Each mark of the mark group is recorded on the steel cable and the pulley by spraying.

5. The method for monitoring elevator brake cable slippage according to claim 1, characterized in that: When the motor controls the pulley to rotate, the steel cable will move with the pulley. When the marks on the steel cable pass through the pulley at regular intervals, they will correspond one by one with the marks on the pulley. Once a displacement difference is detected between the corresponding marks, it is determined that a certain steel cable is slipping or faulty.

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