Cable strain prevention system for tower crane, tower crane and control method

Abstract

The invention discloses a cable strain prevention system for a tower crane, a tower crane and a control method. The cable strain prevention system comprises: a cable receiving device, which is arranged on a lower support of the tower crane and is used for receiving and releasing cables; a measuring device, which is used for measuring the tension value borne by the released cables; and a control device, which is electrically connected to the measuring device and the cable receiving device and is used for controlling the cable receiving and releasing of the cable of the cable receiving device according to the tension value, thereby preventing the strain caused by the cables released by the cable receiving device being too long or too heavy, and ensuring the safety and reliability of the power use of the tower crane.

Description

Technical Field

[0001] The present invention relates to the technical field of crane equipment, and in particular to a cable strain prevention system of a tower crane, a tower crane and a control method. Background Art

[0002] When a tower crane is used for high-rise building construction, the main power cable is pulled from the power supply equipment under the tower to the top of the tower crane to supply power to the electrical equipment on the top of the tower crane. To facilitate the arrangement of vertical cables, a cable reel can be installed on the lower support of the tower crane for cable storage. When the tower crane is raised, the cable is released from the reel; when the tower crane is lowered, the cable reel is used for cable storage.

[0003] However, when the cable is laid vertically, if the free vertical cable is too long and the cable itself is too heavy, it may cause cable strain, leading to safety hazards and reducing the reliability of power supply of the tower crane. In addition, if the cable is fixed to the tower body to prevent the vertical free cable from being too long, if the reel does not release the cable during jacking, excessive tension will be generated on the cable, causing damage to the cable. Summary of the invention

[0004] The purpose of the present invention is to provide a cable strain prevention system for a tower crane, a tower crane and a control method. The cable strain prevention system for a tower crane, the tower crane and the control method have the advantages of avoiding the length of the tower crane cable being released too long and preventing the cable from being strained.

[0005] In order to achieve the above object, the present invention provides a cable strain prevention system for a tower crane, the cable strain prevention system comprising:

[0006] The cable storage device is arranged on the lower support of the tower crane and is used for collecting and releasing the cables;

[0007] A measuring device for measuring the tension value of the released cable;

[0008] The control device is electrically connected to the measuring device and the cable receiving device, and is used for controlling the cable receiving and releasing of the cable of the cable receiving device according to the tension value.

[0009] In an embodiment of the present invention, a tower crane comprises:

[0010] A high voltage power supply is arranged on the ground;

[0011] The transformer is installed on the upper part of the tower crane and connected to the high-voltage power source through cables. It is used to convert high-voltage electricity into low-voltage electricity.

[0012] In an embodiment of the present invention, the height of the tower crane is greater than 100 m, the installation height of the cable storage device is greater than 90 m, and the outer diameter of the cable ranges from 30 mm to 80 mm.

[0013] In an embodiment of the present invention, the cable strain prevention system further comprises a guide device disposed on the lower support and located on one side of the cable receiving device, and the measuring device is disposed on the guide device.

[0014] In an embodiment of the present invention, the guide device is a circular guide frame, and the measuring device is a measuring shaft arranged at the axial center position of the circular guide frame.

[0015] In an embodiment of the present invention, the guiding device is a fan-shaped guiding frame, and the measuring device is an elastic limiting mechanism arranged at the arc edge of the fan-shaped guiding frame.

[0016] In an embodiment of the present invention, the guide device is an arc guide assembly, which includes a guide plate and a movable frame. The movable frame is rotatably arranged on the guide plate and forms a gap with the guide plate. The measuring device is an elastic limiting mechanism arranged in the gap.

[0017] A second aspect of the present invention provides a tower crane, the tower crane comprising the cable strain prevention system for the tower crane described above.

[0018] A third aspect of the present invention provides a control method for a cable strain prevention system of a tower crane, the control method comprising:

[0019] Make sure the tower crane is in the non-lifting state and the cable storage device is in the state of releasing the cable;

[0020] Get the tension value;

[0021] Determining that the pulling force value is greater than a preset threshold;

[0022] Control the cable storage device to stop releasing the cables.

[0023] In an embodiment of the present invention, the control method further includes:

[0024] Make sure the tower crane is in the jacking state;

[0025] Get the tension value;

[0026] Determining that the pulling force value is greater than a preset threshold;

[0027] Control the tower crane to stop the lifting operation.

[0028] Through the above technical scheme, by providing a cable storage device for retracting and releasing cables, and providing a measuring device for measuring the tension value borne by the released cables, and then electrically connecting the control device, the cable storage device and the measuring device, the control device can control the cable retraction and release of the cable storage device according to the tension value, thereby avoiding strain caused by the cable released by the cable storage device being too long or too heavy, thereby ensuring the safety and reliability of the tower crane's electricity use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

[0030] Figure 1 1 is a schematic diagram of the partial structure of the cable strain prevention system in an embodiment of the present invention (the guide device is a circular guide frame);

[0031] Figure 2 1 is a partial structural schematic diagram of a cable strain prevention system in an embodiment of the present invention (the guide device is a fan-shaped guide frame);

[0032] Figure 3 is a schematic diagram of the movable wheel of the elastic limiting mechanism in the embodiment of the present invention when it is not moved;

[0033] Figure 4 is a schematic diagram of the movable wheel of the elastic limiting mechanism in the embodiment of the present invention after movement;

[0034] Figure 5 is a schematic diagram of the movable wheel of the elastic limiting mechanism in the embodiment of the present invention when it is not moved;

[0035] Figure 6 is a schematic diagram of the movable wheel of the elastic limiting mechanism in the embodiment of the present invention after movement;

[0036] Figure 7 It is a structural schematic diagram of a tower crane in an embodiment of the present invention.

[0037] Description of Reference Numerals

[0038] 1 High voltage power supply 2 Transformer

[0039] 3 Cable 4 Cable storage device

[0040] 5 Measuring device 501 Measuring axis

[0041] 502 elastic limit mechanism 5021 moving wheel

[0042] 5022 Elastic support 5023 Mechanical switch

[0043] 6 Guide device 601 circular guide frame

[0044] 602 Fan-shaped guide frame 603 Arc-shaped guide assembly

[0045] 6031 Guide plate 6032 Movable frame

[0046] 7 Lower support 8 Standard section DETAILED DESCRIPTION

[0047] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0048] A specific embodiment of the present invention provides a new type of cable strain prevention system for tower cranes, which is applied in the field of crane equipment technology. Figure 1-Figure 7 As shown, specifically, the cable strain prevention system includes a cable storage device 4, a measuring device 5 and a control device, wherein Figure 7 As shown, the cable storage device 4 is arranged on the lower support 7 of the tower crane, and is used to store and release the cable 3; the measuring device 5 is used to measure the tension value of the released cable 3; the control device is electrically connected to the measuring device 5 and the cable storage device 4, and is used to control the cable storage device 4 to store and release the cable according to the tension value. Specifically, the cable storage device 4 in this embodiment is arranged on the lower support 7 of the tower crane and is fixed relative to the transformer 2, so as to prevent the cable 3 from passing through the rotating device located above the lower support 7, causing the cable 3 to be entangled on the rotating device, and can regularly and orderly store and release the cable 3 vertically lowered from a high place, so as to avoid the cable 3 from being cluttered, and also greatly reduce the difficulty of cable wiring, reduce the wiring workload of the staff, and improve the wiring efficiency.

[0049] Furthermore, since the cable 3 for transmitting high voltage electricity is relatively thick, the weight of the cable 3 per unit length is relatively large. If the cable 3 released from the reel is too long, the weight of the cable 3 itself is too large, which may cause the cable 3 to be strained due to excessive tension. In addition, the tension brought by the overly long free vertical cable 3 will also be transmitted to the reel. If the reel is to withstand the above pressure, a high-power motor (such as 15KW-20KW) or brake needs to be installed, resulting in energy consumption. Therefore, the measuring device 5 in this embodiment is arranged below the cable 3 that is about to be lowered vertically, and can measure the tension value that the cable 3 in a free vertical state after being released is borne, and transmit the tension value to the control device. The control device compares the tension value with a preset threshold value. If the tension value is less than the preset threshold value, it means that the tension value at this time will not cause damage to the cable 3, and the reel can continue to release the cable 3 outward; if the tension value is greater than the preset threshold value, it means that the tension value at this time will cause damage to the cable 3, and the reel should stop releasing the cable 3 outward, or recycle part of the cable 3 onto the reel. After adopting the above method, the power range of the motor driving the reel in this embodiment is 3KW-5KW, which saves energy while ensuring the performance of the reel.

[0050] The cable strain prevention system of the tower crane in this embodiment is provided with a cable storage device 4 for retracting and releasing the cable 3, and a measuring device 5 for measuring the tension value borne by the released cable 3, and then the control device is electrically connected to the cable storage device 4 and the measuring device 5, so that the control device can control the cable retraction and release of the cable storage device 4 according to the tension value, thereby avoiding strain caused by the cable 3 released by the cable storage device 4 being too long or too heavy, thereby ensuring the safety and reliability of the tower crane's electricity use.

[0051] In one embodiment of the present invention, a tower crane includes a high-voltage power supply 1 and a transformer 2, wherein the high-voltage power supply 1 is arranged on the ground; the transformer 2 is arranged on the upper part of the tower crane and connected to the high-voltage power supply through a cable, and is used to convert high-voltage electricity into low-voltage electricity. Specifically, when the lifting moment of the tower crane is large and the height is high (such as the lifting moment is greater than 2000 tons per meter and the height is greater than 100 meters), a high-power motor or control device needs to be arranged on the upper part of the tower crane. At this time, if the power supply scheme of an ordinary tower crane is adopted, that is, a low-voltage power supply (such as 380V) is arranged on the ground, and ordinary cables are used to supply power to the electrical equipment at the top of the tower crane, for example, if the current demand of the electrical equipment is 1600A, the number of ordinary cables required is in the range of 10-20. In the case of a high height of the tower crane, this number of cables will lead to difficult on-site wiring and complicated lines, high cost, and greatly increase the wiring workload of the staff. In this embodiment, a cable 3 for transmitting high voltage electricity (i.e., a high-voltage cable) is used to connect the high-voltage power supply 1 and the transformer 2. Only a small amount of cables 3 can be used to transmit the high voltage electricity from the ground to the upper part of the tower crane, and the high voltage electricity is converted into low voltage electricity through the transformer 2 to meet the electricity demand of the upper electrical equipment of the large tower crane, thereby reducing the number and cost of cables 3 used, reducing the voltage drop, reducing the line loss, and saving energy.

[0052] The high-voltage power supply 1 in this embodiment is provided by a switch cabinet arranged on the ground, and the switch cabinet can also control the power supply or power outage of the high-voltage electricity; the power conversion device 2 is a box-type substation, and an installation platform is arranged on the lower support 7, the slewing device, the upper support, the balance arm or the lifting arm of the tower crane. The box-type substation is arranged on the installation platform, so that the high-voltage electricity (such as 10KV) from the ground is converted into low-voltage electricity (380V) to directly meet the power demand of the upper electrical equipment of the tower crane. In the case of a high height of the tower crane, this power supply method only needs to use a cable 3 for transmitting high-voltage electricity to transmit the high-voltage electricity from the ground to the upper part of the tower crane, which ensures the operating stability of the power supply system of the large tower crane, and greatly reduces the wiring difficulty of the cable 3, reduces the wiring workload of the staff, and improves the wiring efficiency. However, when adopting the above technical solution, it is necessary to set a very long high-voltage cable (such as a length greater than 100 meters) to the upper part of the tower. If the weight of the freely vertical high-voltage cable of this length is too large, it may cause cable strain and lead to safety hazards, and also reduce the power reliability of the tower crane. Therefore, it is necessary to use the cable anti-strain system provided in this embodiment to avoid cable strain.

[0053] In one embodiment of the present invention, the height of the tower crane is greater than 100m, and the setting height of the cable storage device 4 is greater than 90m. In this embodiment, if the height of the tower crane adopts the power supply method of a conventional crane (that is, low-voltage electricity is transmitted to the upper part of the tower crane through a large number of ordinary cables), the main cable is directly placed vertically from the upper part of the tower crane to the ground. The wiring difficulty and wiring workload of the staff are relatively large, and the wiring efficiency is low. If a solution of transmitting high-voltage electricity to the upper part of the tower crane is adopted, the safety risk of the staff is further increased. If the length of the freely vertical cable 3 is not restricted, the cable 3 is subjected to huge tension. For example, the weight of the cable 3 per unit length is 3kg, and the gravity when the 150m cable 3 is all in a freely vertical state is 4500N. The tension increases with the increase of gravity, and the cable 3 will be seriously strained.

[0054] In one embodiment of the present invention, the outer diameter range of the cable 3 is 30mm-80mm. In order to ensure that the tower crane can meet the power consumption requirements of the upper electrical equipment and the voltage drop of the cable 3 is less than 5%, it is further preferred in this embodiment that the outer diameter range of the cable 3 is 50mm-80mm. However, the weight of the cable 3 in this outer diameter range also increases. Therefore, in order to prevent the free vertical cable 3 from being too heavy and causing the cable 3 to be strained, and to avoid bringing excessive tension to the cable storage device 4, the length of the cable 3 released by the cable storage device 4 should be limited.

[0055] In one embodiment of the present invention, the cable strain prevention system further includes a guide device 6 disposed on the lower support 7 and located on one side of the cable receiving device 4, and the measuring device 5 is disposed on the guide device 6. Specifically, the guide device 6 in this embodiment is fixed relative to the cable receiving device 4, and the cable 3 first passes through the guide device 6 and then is wound on the cable receiving device 4, so as to prevent the cable 3 from shaking left and right, so that the cable 3 is in a stable state before entering the cable receiving device 4, and the regularity of the cable 3 wound by the cable receiving device 4 is improved; when the cable 3 is released from the cable receiving device 4, it must pass through the guide device 6 and then freely vertically downward, so the measuring device 5 is disposed on the guide device 6 to conveniently and accurately measure the tension borne by the released cable 3.

[0056] In one embodiment of the present invention, Figure 1 As shown, the guide device 6 is a circular guide frame 601, and the measuring device 5 is a measuring shaft 501 arranged at the axial center position of the circular guide frame 601. The circular guide frame 601 in this embodiment has a pivot center and can rotate around the pivot center (the structure of the circular guide frame 601 is similar to a fixed pulley), and the circular guide frame 601 is arranged on the left side or right side of the cable storage device 4. In this embodiment, the circular guide frame 601 is arranged on the left side of the cable storage device 4, and the cable 3 is wound from the right side of the upper part of the circular guide frame 601 to the left side and freely vertically downward. The measuring shaft 501 is arranged at the axial center position of the circular guide frame 601, which can directly measure the resultant tension exerted on the circular guide frame 601, and further deduce the tension exerted on the released free vertical cable 3 through the resultant tension.

[0057] In another embodiment of the present invention, Figure 2-4As shown, the guide device 6 is a fan-shaped guide frame 602, and the measuring device 5 is an elastic limiting mechanism 502 arranged at the arc edge of the fan-shaped guide frame 602. In this embodiment, the fan-shaped guide frame 602 is in a quarter circle shape, and when the cable 3 is released from the cable storage device 4, it goes around from the upper side of the fan-shaped guide frame 602 to the left side and then freely vertically downward. The angle between the setting direction of the elastic limiting mechanism 502 and the horizontal line is 135 degrees, so the pressure on the fan-shaped guide frame 602 is the greatest when the cable 3 passes through this position. The measured value here is used to infer the tension value, and the release length of the cable 3 is limited to further ensure the safety of the cable 3. Specifically, the elastic limiting mechanism 502 includes a moving wheel 5021, an elastic support member 5022 (such as a spring) and a mechanical switch 5023 electrically connected to the control device, the mechanical switch 5023 having a moving contact, the moving wheel 5021 is arranged at the arc edge of the fan-shaped guide frame 602 and is located below the cable 3 passing therethrough, and can move in a straight line in a direction with an angle of 135 degrees with the horizontal line, one end of the elastic support member 5022 is connected to the center of the moving wheel 5021, and the other end of the elastic support member 5022 is connected to the moving contact of the mechanical switch 5023. As the length of the cable 3 being released increases, the pressure applied by the cable 3 to the moving wheel 5021 also gradually increases, and the moving wheel 5021 gradually moves along its moving path. When the cable 3 is released to a preset length (the tension value generated by the cable 3 of the preset length is the limit value that prevents the cable 3 from being pulled), the moving wheel 5021 moves to the center position of the fan-shaped guide frame 602 and pushes the moving contact through the elastic support 5022 to trigger the mechanical switch 5023. After the mechanical switch 5023 is triggered, it sends a trigger signal to the control device. After receiving the trigger signal, the control device controls the cable storage device 4 to stop releasing the cable 3. Further, in this embodiment, a force sensor can be set at the arc edge of the fan-shaped guide frame 602, and the angle between the setting direction of the force sensor and the horizontal line is 135 degrees, so as to directly measure the tension value of the released cable 3.

[0058] In another embodiment of the present invention, Figure 5-6As shown, the guide device is an arc-shaped guide assembly 603, which includes a guide plate 6031 and a movable frame 6032. The movable frame 6032 is rotatably arranged on the guide plate 6031 and forms a gap with the guide plate 6031. The measuring device 5 is an elastic limiting mechanism 502 arranged in the gap. Specifically, the edge of the guide plate 6031 is in an arc shape, and a rotating wheel is provided at the lower arc end point of the guide plate 6031; the movable frame 6032 is also in an arc shape and forms a gap with the guide plate 6031. The upper arc end point of the movable frame 6032 is rotatably connected to the above-mentioned rotating wheel, so that the movable frame 6032 can rotate relative to the guide plate 6031, that is, the cable 3 is removed from the cable receiving device 4. When the cable 3 is released, it goes around the edge of the guide plate 6031 to the edge of the movable frame 6032 and then freely vertically downward; the elastic limiting mechanism 502 includes an elastic support member 5022 (such as a spring) and a mechanical switch 5023 electrically connected to the control device, and the mechanical switch 5023 has a moving contact. One end of the elastic support member 5022 is always connected to the movable frame 6032, and the other end always rests on the side wall of the guide plate 6031 facing the movable frame 6032; the mechanical switch 5023 is set on the guide plate 6031 and has a telescopic feeler that can trigger the moving contact, and the telescopic feeler faces the movable frame 6032. As the length of the cable 3 released increases, the pressure applied by the cable 3 to the moving wheel 5021 gradually increases, the elastic support member 5022 is continuously compressed, and the movable frame 6032 The gap between the guide plate 6031 gradually becomes smaller. When the cable 3 is released to a preset length (the tension value generated by the preset length of the cable 3 is the limit value that prevents the cable 3 from being strained), the gap becomes smaller to a certain extent, and the telescopic antenna of the mechanical switch 5023 retracts and triggers the moving contact under the squeezing action of the movable frame 6032. After being triggered, the mechanical switch 5023 sends a trigger signal to the control device. After receiving the trigger signal, the control device controls the cable storage device 4 to stop releasing the cable 3.

[0059] In one embodiment of the present invention, the cable strain prevention system further comprises a plurality of cable fixings, which are arranged at equal intervals along the tower height of the tower crane. Specifically, the cable fixings in this embodiment are cable clamps, which are arranged at equal intervals along the tower height of the tower crane, and are used to fix part of the cables 3 to the standard section 8 of the tower crane, so that the standard section 8 bears the weight of part of the released cables 3, so as to reduce the length of the cables 3 in a free vertical state, avoid all the released cables 3 in a free vertical state, form better protection for the cables 3, and reduce the possibility of the cables 3 being strained.

[0060] Another embodiment of the present invention provides a tower crane, which includes the cable strain prevention system for the tower crane provided by the above embodiment.

[0061] Another embodiment of the present invention provides a control method for a cable strain prevention system of a tower crane, the control method comprising the following steps:

[0062] Step S101: determining that the tower crane is in a non-lifting state and the cable storage device 4 is in a state of releasing the cable 3;

[0063] Step S102: obtaining a tension value;

[0064] Step S103: Determine whether the pulling force value is greater than a preset threshold;

[0065] Step S104: Control the cable storage device 4 to stop releasing the cable 3.

[0066] It can be understood that a key reason for the cable 3 of the tower crane in this embodiment to be pulled is that the weight of the cable 3 per unit length is large. If the cable 3 released by the cable receiving device 4 is too long (that is, the cable 3 in a free vertical state is too long), the cable 3 will be subjected to excessive tension and be pulled. To avoid the above situation, the control device, the measuring device 5, and the cable receiving device 4 of the tower crane cooperate with each other to limit the length of the cable 3 released.

[0067] Specifically, the jacking system of the tower crane used to implement the jacking operation will send a jacking signal to the control device before performing the jacking operation (if the jacking system does not perform the jacking operation, it will not send a jacking signal to the control device), and the control device determines that the tower crane is in the jacking state after receiving the jacking signal; the cable storage device 4 will send a cable release signal to the control device before releasing the cable 3, and the control device determines that the cable storage device 4 is in the cable release 3 state after receiving the cable release signal.

[0068] If the control device does not receive the lifting signal but receives the cable release signal, it is determined that the tower crane is in a non-lifting state and the cable storage device 4 is in a cable release state; then the control measuring device 5 is controlled to continuously collect the tension value borne by the released cable 3, and the measuring device 5 transmits the tension value to the control device after collecting it; the control device then compares the tension value with the pre-stored preset threshold value, if the tension value is less than the preset threshold value, it means that the tension value at this time will not cause the cable 3 to be strained, and the cable storage device 4 can continue to release the cable 3; if the tension value is greater than the preset threshold value, it means that the tension value at this time will cause the cable 3 to be strained, and the cable storage device 4 should stop releasing the cable 3; further, in order to reduce the tension borne by the cable 3, the control device can also control the cable storage device 4 to rotate in the opposite direction to recycle part of the cable 3 onto the cable storage device 4.

[0069] In one embodiment of the present invention, the control method further includes:

[0070] Step S201: determining that the tower crane is in a jacking state;

[0071] Step S202: obtaining a tension value;

[0072] Step S203: Determine whether the pulling force value is greater than a preset threshold;

[0073] Step S204: Control the tower crane to stop the lifting operation.

[0074] It can be understood that another key reason that may cause the cable 3 of the tower crane in this embodiment to be pulled is that during the lifting operation, the lower end and the upper end of the cable 3 are fixed respectively (wherein the lower end of the cable 3 is fixed on the standard section 8, and the upper end is fixed on the cable storage device 4), and the operator misoperates (that is, the operator does not pre-place a sufficient length of cable 3 before performing the lifting operation) so that the length of the middle free vertical cable 3 is less than the lifting height, which will cause the middle cable 3 to be over-stretched and thus cause strain. To avoid the above situation, the control device, the measuring device 5, and the cable storage device 4 of the tower crane cooperate with each other to control the stopping of the tower crane's lifting operation.

[0075] Specifically, if the control device receives a lifting signal, it determines that the tower crane is in a lifting state; then the control measuring device 5 is controlled to continuously collect the tension value borne by the cable 3, and the measuring device 5 transmits the tension value to the control device after collecting the tension value; the control device then compares the tension value with a pre-stored preset threshold value. If the tension value is less than the preset threshold value, it means that the tension value at this time will not cause the cable 3 to be strained, and the lifting system can continue to perform the lifting operation; if the tension value is greater than the preset threshold value, it means that the tension value at this time will cause the cable 3 to be strained, and the lifting system should immediately stop the lifting operation; further, after the lifting operation stops, the control system can control the cable storage device 4 to continue to release a certain length of cable 3, thereby reducing the tension of the middle part of the cable 3 and increasing the length of the middle part of the cable 3, so as to continue the lifting operation afterwards.

[0076] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any appropriate manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

[0077] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0079] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A cable strain prevention system for a tower crane, characterized in that: The cable strain prevention system comprises: A cable storage device (4) is arranged on a lower support (7) of the tower crane and is used for storing and retrieving the cable (3); A measuring device (5) for measuring the tension value borne by the released cable (3); a control device, electrically connected to the measuring device (5) and the cable receiving device (4), and used for controlling the retraction and extension of the cable (3) of the cable receiving device (4) according to the tension value; The guide device (6) is arranged on the lower support (7) and is located on one side of the cable receiving device (4); the measuring device (5) is arranged on the guide device (6), wherein: The guide device (6) is a fan-shaped guide frame (602), the measuring device (5) is an elastic limiting mechanism (502) arranged at the arc-shaped edge of the fan-shaped guide frame (602), and the pressure exerted on the fan-shaped guide frame (602) by the cable (3) passing through the setting position of the elastic limiting mechanism (502) is the greatest; or, The guide device is an arc-shaped guide assembly (603), the arc-shaped guide assembly (603) comprises a guide plate (6031) and a movable frame (6032), the movable frame (6032) is rotatably arranged on the guide plate (6031) and forms a gap with the guide plate (6031), and the measuring device (5) is an elastic limiting mechanism (502) arranged in the gap; Wherein, the elastic limiting mechanism (502) comprises an elastic support member (5022) and a mechanical switch (5023) electrically connected to the control device.

2. The cable strain prevention system for a tower crane according to claim 1, characterized in that: The tower crane comprises: A high voltage power supply (1) is arranged on the ground; A transformer (2) is arranged on the upper part of the tower crane and is connected to the high-voltage power source (1) via the cable (3), and is used to transform high-voltage electricity into low-voltage electricity.

3. The cable strain prevention system for a tower crane according to claim 2, characterized in that: The height of the tower crane is greater than 100 m, the installation height of the cable storage device (4) is greater than 90 m, and the outer diameter of the cable (3) ranges from 30 mm to 80 mm.

4. A tower crane, characterized in that: The tower crane comprises the cable strain prevention system for a tower crane according to any one of claims 1-3.

5. A control method for a cable strain prevention system of a tower crane, applicable to the cable strain prevention system of a tower crane according to any one of claims 1 to 3, characterized in that: The control method comprises: Determining that the tower crane is in a non-lifting state and the cable storage device (4) is in a cable-releasing state; Obtaining the tension value; Determining that the pulling force value is greater than a preset threshold; The cable storage device (4) is controlled to stop releasing the cable (3).

6. The control method of the cable strain prevention system of a tower crane according to claim 5, characterized in that: The control method further comprises: Determining that the tower crane is in a jacking state; Obtaining the tension value; Determining that the pulling force value is greater than a preset threshold; The tower crane is controlled to stop the lifting operation.

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