Sling monitoring devices and crane systems

Abstract

The present invention provides a rope monitoring device and a crane system that prompts the user to perform inspections near the end of the rope in a focused manner and helps to use a hoist in a safe state. A hoisting motor (3) that rotates a drum for winding up a rope (2), a load swing angle detection device (110), and an inverter control device (12) that controls the hoisting motor (3) are provided. The hoisting motor (3) measures the number of times the rope (2) is bent near the end support device for each load based on the output of the load swing angle detection device (110) and the load state estimated from the output current and rotation state of the hoisting motor (3), thereby monitoring the rope and recording the number of times the rope is bent for each load state.

Description

Technical Field

[0001] The present invention relates to monitoring of a sling used in a crane device included in a crane system, and more particularly to a technique for detecting bending of the sling. Background Art

[0002] The ropes used in cranes and the like deteriorate with use, so they need to be inspected regularly to check the deterioration status. In a two-strand suspension crane, the sheave passage part often has a large loss, but depending on the usage, there are also cases where the loss near the end of the rope is large. This is because when the hoist moves laterally, the load swings, which causes the rope to shake, and stress is concentrated on the end of the rope (rope end).

[0003] In order to reduce the stress concentration on the rope end, there is a case where a rope end support device is used in which a rope is wound around a sheave and the rope end is locked. This makes it possible to prevent stress from concentrating on the rope end.

[0004] In addition, by attaching the rope end support device to the hoist via a pin, the influence of the swing of the load generated during the longitudinal movement is reduced.

[0005] However, although it can reduce stress concentration compared to a simple end support device, it is still a location where load concentrates and is a location that must be inspected.

[0006] Patent document 1 describes a rope monitoring device which, as an aid in inspecting the rope state, measures the number of bends of the rope per unit length under a load, thereby monitoring the rope and focusing on inspecting the most bent parts of the rope.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2010-149980 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, the above-mentioned rope monitoring device monitors the rope based on the bending frequency determined by the sheave or drum. In this technology, the bending frequency is measured using pulses of an encoder of the crane system, but there is a problem that the state near the end of the rope cannot be known.

[0012] Therefore, the present invention aims to be able to know the number of bends of the entire rope including a portion that cannot be measured by the pulses of an encoder.

[0013] Technical solutions to solve problems

[0014] To achieve the object, in the present invention, bending is detected according to the periodically detected swing angle of the weight, and the number of times of bending is counted.

[0015] More specifically, the invention relates to a cable monitoring device for controlling a crane system that moves a weight held by a holding mechanism connected to a cable, and includes a control unit that measures the number of bends of the cable, and an information storage unit that stores the number of bends measured by the control unit. The control unit receives the periodically detected weight swing angle of the cable from a weight swing angle detection device, compares whether the weight swing angle is greater than a predetermined threshold, detects a change in the weight swing direction of the cable using the periodically detected weight swing angle, and determines that the cable is bent when the weight swing angle is greater than the threshold and a change in the weight swing direction is detected, and counts the number of bends of the cable.

[0016] Furthermore, the present invention also includes a crane system including the rope monitoring device, a monitoring method of the rope monitoring device, or a bend counting method.

[0017] Effects of the Invention

[0018] According to the present invention, the number of times the entire rope is bent can be measured, so that the load state or the load state (hereinafter referred to as the load state) near the end of the rope can be monitored. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an example of a configuration diagram of an inverter type crane system in one embodiment of the present invention.

[0020] Figure 2 This is an example of a structural diagram of a rope end support device of a hoist in one embodiment of the present invention.

[0021] Figure 3 This is an example of a control system of a sling monitoring device in one embodiment of the present invention.

[0022] Figure 4 This is an example of an inverter control device in one embodiment of the present invention.

[0023] Figure 5 It is a figure which shows the bending state of the sling in one Example of this invention.

[0024] Figure 6 This is an example of displaying the number of bending times of the sling in one embodiment of the present invention.

[0025] Figure 7This is an example of a control flow for counting the number of times the rope is bent in one embodiment of the present invention.

[0026] Figure 8 It is a diagram showing the principle of step S5 in one embodiment of the present invention.

[0027] Fig. 9 It is a figure which shows the measurement data and the bending frequency table used in one Example of this invention. DETAILED DESCRIPTION

[0028] use Figure 1 An example of the structure of the inverter type crane system in this embodiment is described. The hoisting motor 3 constituting the crane system is controlled by the inverter control device 12 which has received an operation command from the operation input device 11. That is, the hoisting motor 3 rotates the drum around which the rope 2 is wound via the speed reducer, thereby raising and lowering the rope 2 and moving the weight attached to the hook 1 as a holding mechanism for the weight in the Z-axis direction.

[0029] In addition, the inverter control device 12 that has received the motion command from the operation input device 11 controls the lateral movement motor 5, and the weight mounted on the hook 1 is moved in the X-axis direction through the lateral movement device 6 and the lateral movement bridge 7. In this embodiment, the hook 1 is shown as an example of a holding mechanism, but other holding mechanisms such as a ring, a shackle, a rope, etc. can also be used.

[0030] In addition, the longitudinal movement inverter control device 13 that has imported the action command from the operation input device 11 controls the longitudinal movement motor 8, and the weight installed on the hook 1 is moved in the Y-axis direction through the longitudinal movement device 9 and the longitudinal movement bridge 10.

[0031] In addition, in this embodiment, the inverter control device 12 counts the number of times the rope 2 is bent. That is, the inverter control device 12 is used as a rope monitoring device. However, a rope monitoring device may be separately provided to count the number of times the rope is bent.

[0032] Next, use Figure 2 An example of the structure of the rope end support device 14 will be described.

[0033] The cable end support device 14 is a structure for winding the cable 2 and locking the cable end portion 16. As a result, it becomes a structure that stress is not concentrated on the cable end portion 16. In addition, by being installed on the drum 4 via the pin 15, the influence of the weight swing that occurs when moving in the Y-axis direction is reduced. As described later, in this embodiment, the number of bends of the cable 2 near the cable end support device 14 shown in the figure is counted. Among them, in this embodiment, the number of bends refers to the number of times the cable 2 is bent to a predetermined weight swing angle or more.

[0034] Next, use Figure 3 The control of the control object (motor, etc.) by the control system composed of the inverter control device 12 and the inverter control device 13 for longitudinal movement is described. The hoisting motor 3 and the lateral movement motor 5 are controlled by the inverter control unit 103 provided in the inverter control device 12. That is, when receiving a prescribed action command from the operation input device 11, the inverter control unit 103 generates an inverter control signal based on the action command, and controls each inverter, the hoisting inverter 101, and the lateral movement inverter 102 through the inverter control signal. In addition, the hoisting inverter 101 and the lateral movement inverter 102 output the frequency, voltage, and current required for driving the hoisting motor 3 and the lateral movement motor 5.

[0035] Furthermore, the inverter control device 12 controls the release of the hoisting brake 106 and the lateral movement brake 107 which are implemented by electromagnetic brakes, and moves in various directions (Z, X) while holding the weight attached to the hook 1.

[0036] Next, use Figure 4 An example of the configuration of the inverter control device 12 will be described.

[0037] The inverter control device 12 includes a control unit 201, an information storage unit 202, and an output unit (not shown). The control unit 201 controls the hoisting and lateral movement inverter 102 based on an operation command from the operation input device 11 to drive each motor (the hoisting motor 3, the lateral movement motor 5).

[0038] The control unit 201 estimates the load state corresponding to the hoisting rope 2. The load state is estimated using the frequency, current value, and voltage obtained from the hoisting inverter 101, the weight of the weight corresponding to the hoisting rope (hanging weight) and the output torque calculated based on them, and the rotation state (pulse signal) of the hoisting motor 3 obtained from the encoder 109 (rotation detection unit). Then, the control unit 201 controls the hoisting inverter 101 using the load state. In order to detect the rotation state of the hoisting motor 3, a pulse signal corresponding to the rotation speed generated by the encoder 109 installed on the rotating shaft of the hoisting motor 3 can be used.

[0039] The information storage unit 202 stores a threshold value for determining the load state of the drum 4 loaded with the inverter control device 12. The load state is determined based on the current value output from the hoisting inverter 101 to the hoisting motor 3 and the motor rotation speed during the hoisting operation.

[0040] The control unit 201 imports the output of the weight swing angle detection device 110, measures the weight swing angle, and obtains the state of the weight swing.

[0041] The weight swing angle detection device 110 may be any method that can detect the weight swing angle, such as a method using a gyro sensor or an acceleration sensor, or a method that calculates based on the change in tension of the rope caused by the weight swing (change in load on the sheave, etc.).

[0042] The information storage unit 202 temporarily stores the weight swing angle obtained by the control unit 201. Then, when the control unit 201 detects a point where the weight swing direction changes, it determines that a bend has occurred near the end of the rope, counts the number of bends, and stores it in the information storage unit 202. Figure 5 The bending condition is shown in FIG. Figure 5 The sling 2 wound on the sling end support device 14 is shown to be swaying left and right, that is, bending. Figure 7 The details of this processing will be described later.

[0043] In addition, when the information storage unit 202 stores the number of bending times, it also stores the above-mentioned load state.

[0044] Next, use Figure 6 The display of the measurement contents (the number of bends and the load state) will be described. Figure 6 The display content and its changing status on the display device (not shown) connected to the inverter control device 12 are shown. In the display screen, the number of bends near the end of the suspension rope is displayed by the total number of bends and each load classification. That is, Figure 6 The top portion of the display shows the total number of swings of the weight counted, and below it, the load classification (the leftmost display area) and the number of bends during the load classification (the right side of the load classification display area) are displayed together. Here, the display changes according to the control of the control unit 201 or the user's operation of the display device. In this case, the display can be automatically switched at regular intervals or repeatedly displayed.

[0045] Among them, regarding the load classification, for example, as a ratio relative to the rated load, 0-10% is no load, 11-25% is light load, 26-50% is medium load, 51-75% is heavy load, 76-100% is overload, and 101% or more is overload, the number of bends is displayed. In this way, by displaying the number of bends stored in the information storage unit on the display device according to each load, the use status of the sling can be visualized in detail. In addition, Figure 6 The display is performed by the control unit 201 using the bending frequency table 2022 stored in the information storage unit 202. The bending frequency table 2022 is as follows: Fig. 9 As shown, the content thereof will be described later.

[0046] Finally, use Figure 7 The control flow for counting the number of bends will be described.

[0047] First, as a prerequisite of the process, in the crane system, the heavy object is moved according to the control of the control system. In addition, this process is repeatedly performed when the heavy object moves, and in step S1, the "last value" of the hanging weight swing angle is stored in the information storage unit 202.

[0048] First, in step S1, the control unit 201 obtains the weight swing angle based on the output of the weight swing angle detection device 110. This is performed periodically. That is, in the weight swing angle detection device 110, the weight swing angle is measured periodically, and the result is output each time. In addition, in step S1, the control unit 201 calculates the load state using the above method. Then, the control unit 201 stores the calculated load state in the "Load (%)" column of the measurement data of the information storage unit 202. In addition, at this time, the control unit 201 stores the time in the "Measurement time" column.

[0049] Next, in step S2, the control unit 201 determines whether the weight swing angle is above a certain angle in order to remove a small weight swing angle. The small weight swing angle is an angle (a certain angle) pre-stored in the information storage unit 202. The reason for removing it is that it can be determined that no bending occurs when it is less than a certain angle. As a result, if it is above a certain angle, proceed to step S3. If it is less than a certain angle (not above a certain angle), proceed to step S4. Here, when proceeding to step S3, the number of bends is counted together with the subsequent steps.

[0050] When the process proceeds to step S4, the counting process of the number of bends is terminated and the process returns to step S1.

[0051] In step S4, the control unit 201 clears the "last value" of the weight swing angle stored in the information storage unit 202. The last value refers to the weight swing angle (current value) stored in step S7 previously executed in the repeatedly executed process.

[0052] Next, the processing after step S3 for counting the number of bends will be described. In step S3, the control unit 201 compares the previous value stored in the information storage unit 202 with the weight swing angle (current value) acquired in step S1.

[0053] Next, in step S5, the control unit 201 determines whether the swing direction of the hanging weight has changed based on the comparison result of step S4. Specifically, the control unit 201 uses the magnitude relationship between the previous value and the current value stored in the information storage unit 202. If the previous value is larger, it is determined that the swing direction of the hanging weight has changed. On the contrary, if the current value is larger, it is determined that the swing direction of the hanging weight has not changed.

[0054] For the principle of this judgment, Figure 8 Provide explanation. Figure 8 In the figure, 20-1 to 20-3 respectively represent reference lines (eg, center lines) of the sling. Among them, the reference line 20-1 is the reference of the position of the sling 2 in the last repeated process. That is, θ1 is stored in the information storage unit 202 as the last value.

[0055] Afterwards, as the weight is moved, the weight swing of the sling 2 becomes one of the reference lines 20-2 or 20-3. First, the case where the sling 2 changes from the reference line 20-1 to the reference line 20-2 is described. In this case, the reference line 20-2 is closer to the center line 30 than the reference line 20-1. That is, it means that (1) the weight swing direction from the center line 30 to the reference line 20-1 and (2) the direction from the reference line 20-1 to the reference line 20-2 change in different directions. Here, the weight swing angle θ1 of the reference line 20-1 and the weight swing angle θ2 (current value) of the reference line 20-2 satisfy the relationship θ1>θ2. That is, because the previous value is larger, it is judged that the weight swing direction has changed.

[0056] In addition, the case where the sling 2 changes from the reference line 20-1 to the reference line 20-3 is described. In this case, the reference line 20-3 is farther from the center line 30 than the reference line 20-1. That is, (1) the weight swing direction from the center line 30 to the reference line 20-1 is the same as (2) the direction from the reference line 20-1 to the reference line 20-3. In other words, the weight swing of the sling 2 changes in the same direction as the center line 30, the reference line 20-1, and the reference line 20-3. Here, the weight swing angle θ1 of the reference line 20-1 and the weight swing angle θ3 of the reference line 20-3 satisfy the relationship θ1<θ3 (current value). That is, because the current value is large, it is judged that the weight swing direction has not changed.

[0057] In addition, when the previous value is not stored in the information storage unit 202 due to the previous repeated processing S4 or the initial processing, it is determined that there is no change in the swing direction of the hanging weight, and the process proceeds to step S7.

[0058] If the result of the determination in step S5 is that the swing direction of the weight has not changed, the process proceeds to step S7. If the result of the determination in step S5 is that the swing direction of the weight has changed, the process proceeds to step S6.

[0059] In step S6, the control unit 201 counts up the number of bends. That is, the control unit 201 records information indicating that the bending is determined as "yes" in the "bending" column of the measurement data stored in the information storage unit 202. Then, the control unit 201 increases the number of bends in the corresponding load column of the bending number table 2022 by 1, corresponding to the "load (%)" corresponding to "yes" in the measurement data 2021. In addition, the control unit 201 calculates and records the total number of bends for each load, that is, the total number of bends.

[0060] As described above, the measurement data 2021 records various data obtained by calculation, measurement, etc. by the control unit 201. Then, the bending frequency table 2022 is generated by the control unit 201 based on the measurement data 2021. In addition, the recording of the bending frequency table 2022 can be performed every time, or it can be performed all at once after the movement of the weight is completed.

[0061] Next, in step S7, the control unit 201 overwrites the current value as the previous value and stores it in the information storage unit 202. Then, the process returns to step S1 and the process shown in this flowchart is repeated.

[0062] In addition, the order of step S2 and step S5 of this flowchart can also be reversed or executed in parallel. That is, the change of the swing direction of the weight can be confirmed (step S5), and then it can be determined whether the swing angle of the weight is above a certain angle (step S2), or they can be performed in parallel. In these cases, if it is determined that the swing angle of the weight is not above a certain value, the previous value is cleared to zero (step S4).

[0063] In addition, when predetermined conditions such as user input and power off of the crane system are satisfied, the processing shown in this flowchart is terminated.

[0064] According to this embodiment, it is possible to prompt the user to focus on the inspection near the end of the rope and use the hoist in a safe state. In addition, since the number of bends of the entire rope including the end of the rope can be known, it is possible to prompt the user to perform a more focused inspection during the inspection.

[0065] Description of Reference Numerals

[0066] 1…Hook

[0067] 2…Sling

[0068] 3…Winching motor

[0069] 4…Reel

[0070] 5…Motor for lateral movement

[0071] 6… Lateral movement device

[0072] 7…Bridge for horizontal movement

[0073] 8…Motor for longitudinal movement

[0074] 9…Device for longitudinal movement

[0075] 10… Bridge for longitudinal movement

[0076] 11…Operation input device

[0077] 12…Inverter control device

[0078] 13…Inverter control device for longitudinal movement

[0079] 14…Sling end support device

[0080] 15…Pin

[0081] 16…End of rope

[0082] 101…Winches inverter

[0083] 102…Inverter for lateral movement

[0084] 103…Inverter control unit

[0085] 104…Inverter for longitudinal movement

[0086] 105…Inverter control unit for longitudinal movement

[0087] 106…Winches brake

[0088] 107… Lateral movement brake

[0089] 108… Brake for longitudinal movement

[0090] 109…Encoder

[0091] 110…Hanging weight swing angle detection device

[0092] 201…Control Department

[0093] 202 ...information storage unit.

Claims

1. A sling monitoring device for controlling a crane system capable of moving a load held by a holding mechanism connected to a sling, the sling monitoring device comprising: a control unit that measures the number of bends of the sling; and an information storage unit for storing the number of bending times measured by the control unit, The control unit, receiving the periodically detected swing angle of the sling from the swing angle detection device, Compare whether the swing angle of the hanging weight is greater than a predetermined threshold value, Using the periodically detected weight swing angle, a change in the weight swing direction of the sling is detected, When the weight swing angle is larger than a threshold value and a change in the weight swing direction is detected, it is determined that a bend has occurred in the rope, and the number of times the rope has been bent is counted.

2. The sling monitoring device according to claim 1, characterized in that: The control unit compares the last value of the weight swing angle stored in the information storage unit with the current value of the weight swing angle received from the weight swing angle detection device for the change in the weight swing direction, and detects that the weight swing direction has changed when the current value is smaller than the last value.

3. The sling monitoring device according to claim 2, characterized in that: The control unit deletes the previous value stored in the information storage unit when the current value is smaller than the threshold value, and overwrites and stores the current value in the information storage unit when the current value is larger than the threshold value.

4. The sling monitoring device according to any one of claims 1 to 3, characterized in that: The control unit, Determine the load state for the sling, The number of bending times is stored in the information storage unit for each load state.

5. The sling monitoring device according to claim 4, characterized in that: The crane system has an end support device for supporting an end of the sling, The control unit measures the number of bends in the rope near the terminal support device as the number of bends.

6. A crane system capable of moving a heavy object held by a holding mechanism connected to a sling, characterized in that: have: a control unit that measures the number of bends of the sling; an information storage unit that stores the number of bending times measured by the control unit; and A device for detecting the swing angle of a sling periodically detects the swing angle of the sling. The control unit, receiving the weight swing angle from the weight swing angle detection device, Compare whether the swing angle of the hanging weight is greater than a predetermined threshold value, Using the periodically detected weight swing angle, a change in the weight swing direction of the sling is detected, When the weight swing angle is larger than a threshold value and a change in the weight swing direction is detected, it is determined that a bend has occurred in the rope, and the number of times the rope has been bent is counted.

7. The crane system according to claim 6, characterized in that: The control unit compares the last value of the weight swing angle stored in the information storage unit with the current value of the weight swing angle received from the weight swing angle detection device for the change in the weight swing direction, and detects that the weight swing direction has changed when the current value is smaller than the last value.

8. The crane system according to claim 7, characterized in that: The control unit deletes the previous value stored in the information storage unit when the current value is smaller than the threshold value, and overwrites and stores the current value in the information storage unit when the current value is larger than the threshold value.

9. The crane system according to any one of claims 6 to 8, characterized in that: The control unit, Determine the load state for the sling, The number of bending times is stored in the information storage unit for each load state.

10. The crane system according to claim 9, characterized in that: It also has an end support device for supporting the end of the sling, The control unit measures the number of bends in the rope near the terminal support device as the number of bends.

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