Pre-tightening method for superlift cable, superlift device, and crane

Abstract

A pre-tightening method for a superlift cable (1), a superlift device, and a crane. The method comprises: receiving a superlift cable pre-tightening instruction; on the basis of the superlift cable pre-tightening instruction, controlling a luffing mast (2) to rotate to a target position at which the luffing mast (2) is inclined relative to a base boom, and controlling a hoisting mechanism (5) to adjust the take-up and pay-off amount of a superlift cable (1), so that the superlift cable (1) is pre-tensioned; and locking the hoisting mechanism (5), and controlling the luffing mast (2) to rotate to a target position in a direction in which the luffing mast (2) trends to be perpendicular to a crane boom, so that the superlift cable (1) is tensioned, wherein the tension of the superlift cable (1) when pre-tensioned is less than the tension thereof when tensioned.

Description

Superlift cable pre-tightening method, superlift device and crane

[0001] This application claims priority to Chinese patent application No. 202311119301.1 filed on August 31, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the technical field of lifting equipment, and in particular to a method for pre-tightening a super-lifting cable, a super-lifting device, and a crane. Background Art

[0003] As cranes have evolved, booms have become increasingly longer. However, the height and width of the boom's cross-section are subject to various limitations, limiting their growth. This increases the boom's slenderness ratio, leading to increased lateral deflection and reduced boom rigidity, limiting the crane's lifting capacity. Cranes with long booms often employ superlift devices to address this issue. Technical issues

[0004] The present application provides a method for pre-tightening a super-lift cable, a super-lift device and a crane, so as to solve the defect of insufficient pre-tightening when pre-tightening the super-lift cable using a super-lift winch in the prior art. Technical Solutions

[0005] The present application provides a pre-tightening method for a super-lift cable, wherein the first end of the super-lift cable is fixedly connected to the terminal arm of a crane boom, the crane boom is provided with a luffing mast, the first end of the luffing mast is rotatably connected to the basic arm of the crane boom, a hoisting mechanism is provided on the luffing mast, the second end of the super-lift cable is connected to the hoisting mechanism after sequentially passing through the second end of the luffing mast and a first winding structure fixed to the basic arm, the first end of the luffing mast is located between the first winding structure and the first end of the super-lift cable, and the pre-tightening method for the super-lift cable comprises:

[0006] Receive the super-lift cable pre-tightening instruction;

[0007] According to the super-lift cable pre-tensioning instruction, the luffing mast is controlled to rotate to a target position inclined relative to the basic arm, and the hoisting mechanism is controlled to adjust the retraction and extension amount of the super-lift cable to pre-tension the super-lift cable;

[0008] The hoisting mechanism is locked, and the luffing mast is controlled to rotate to a target position in a direction perpendicular to the boom, so that the super-lift cable is tensioned, wherein the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning.

[0009] According to a method for pre-tightening a superlift cable provided in the present application, when the luffing mast is at the target position, the difference between the inclination angle of the basic arm and the inclination angle of the terminal arm reaches a target difference.

[0010] According to a method for pre-tightening a superlift cable provided in the present application, the step of obtaining the difference between the inclination angle of the basic arm and the inclination angle of the terminal arm includes:

[0011] Obtaining a first inclination angle of the basic arm relative to a horizontal line and a second inclination angle of the distal arm relative to the horizontal line;

[0012] The difference between the inclination angle of the basic arm and the inclination angle of the terminal arm is determined according to the first inclination angle and the second inclination angle.

[0013] According to a pre-tightening method for a superlift cable provided by the present application, the absolute value of the target difference is less than or equal to 2 degrees.

[0014] According to a method for pre-tightening a superlift cable provided in the present application, when the luffing mast is at the target position, the luffing mast is perpendicular to the boom.

[0015] According to a method for pre-tightening a superlift cable provided by the present application, before controlling the luffing mast to rotate relative to the base arm to a target position inclined relative to the base arm, the method further includes:

[0016] According to the super-lift cable pre-tightening instruction, the boom is controlled to rotate until the boom is tilted relative to the horizontal line.

[0017] According to a method for pre-tightening a superlift cable provided in the present application, the angle between the crane arm and the horizontal line is 74-80 degrees.

[0018] The present application also provides a pre-tensioning device for a super-lift cable, wherein the first end of the super-lift cable is fixedly connected to the terminal arm of a boom, the boom is provided with a luffing mast, the first end of the luffing mast is rotatably connected to the basic arm of the boom, a hoisting mechanism is provided on the luffing mast, the second end of the super-lift cable is connected to the hoisting mechanism after sequentially passing through the second end of the luffing mast and a first winding structure fixed to the basic arm, the first end of the luffing mast is located between the first winding structure and the first end of the super-lift cable, and the pre-tensioning device for the super-lift cable comprises:

[0019] A receiving module, used for receiving a superlift cable pre-tightening instruction;

[0020] a first control module, configured to control the luffing mast to rotate to a target position inclined relative to the base arm according to the super-lift cable pre-tensioning instruction, and to control the hoisting mechanism to adjust the retraction and extension amount of the super-lift cable to pre-tension the super-lift cable;

[0021] The second control module is used to lock the hoisting mechanism and control the variable-length mast to rotate to a target position in a direction perpendicular to the lifting arm to tension the super-lift cable, wherein the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning.

[0022] The present application also provides a crane, comprising a controller, wherein the controller is suitable for executing the above-mentioned method for pre-tightening the superlift cable.

[0023] A crane provided according to the present application also includes:

[0024] a first inclination sensor, adapted to collect an angle between the base arm and a horizontal line, obtain a first inclination signal, and send the first inclination signal to the controller;

[0025] The second inclination sensor is adapted to collect the angle between the distal arm and the horizontal line, obtain a second inclination signal, and send the second inclination signal to the controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in this application or the prior art, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0027] FIG1 is a schematic structural diagram of a superlift device provided by the present application;

[0028] FIG2 is a flow chart of a method for pre-tightening a superlift cable provided in the present application;

[0029] FIG3 is a schematic structural diagram of the pre-tightening device for the super-lift cable provided in the present application.

[0030] Reference numerals:

[0031] 1. Superlift cable; 2. Luffing mast; 3. First pulley; 4. Second pulley; 5. Hoisting mechanism; 6. Hydraulic cylinder; α, first preset angle; 7. Receiving module; 8. First control module; 9. Second control module. Modes for Carrying Out the Invention

[0032] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0033] The following describes the pre-tightening method of the super-lift cable of the present application with reference to FIG1 and FIG2.

[0034] As shown in Figures 1 and 2, in the pre-tensioning method for the super-lift cable provided in the embodiments of the present application, the super-lift cable 1 requires a specific winding method. Specifically, the first end of the luffing mast 2 is rotatably connected to the base arm of the boom. An adjustment mechanism is provided between the luffing mast 2 and the base arm for adjusting the angle between the luffing mast 2 and the base arm. The adjustment mechanism can be, but is not limited to, a hydraulic cylinder 6, the ends of which are rotatably connected to the luffing mast 2 and the base arm, respectively.

[0035] The luffing mast 2 is equipped with a hoisting mechanism 5, and the base boom is equipped with a first winding structure. The first end of the super-lift cable 1 is fixedly connected to the end boom of the boom. The second end of the super-lift cable 1 is connected to the second end of the luffing mast 2 and the first winding structure before being connected to the hoisting mechanism 5. The hoisting mechanism 5 can retract and extend the super-lift cable 1. The first end of the luffing mast 2 is located between the first winding structure and the first end of the super-lift cable 1.

[0036] A second winding structure may be provided at the second end of the luffing mast, and the second winding structure is used to ensure the stability of the superlift cable 1 wound around the second end of the luffing mast 2 .

[0037] The first winding structure and the second winding structure may be, but are not limited to, pulley structures. Referring to FIG. 1 , the first winding structure is the first pulley 3 , and the second winding structure is the second pulley 4 .

[0038] As shown in FIG2 , based on the above structure, the pre-tightening method of the super-lift cable provided in the embodiment of the present application mainly includes the following steps:

[0039] Step 110: receiving a superlift cable pre-tightening instruction;

[0040] Step 120: According to the super-lift cable pre-tensioning instruction, control the luffing mast to rotate to a target position inclined relative to the basic arm, and control the hoisting mechanism to adjust the retraction and extension amount of the super-lift cable to pre-tension the super-lift cable.

[0041] Step 130: Lock the hoisting mechanism and control the luffing mast to rotate to a target position in a direction perpendicular to the boom, so as to tension the super-lift cable, wherein the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning.

[0042] First, through a large amount of data analysis and verification, the applicant found that when the variable-length mast 2 rotates in a direction away from the boom, that is, when the variable-length mast 2 gradually rotates in a direction toward perpendicular to the boom, the sum of the distance between the first end of the super-lift cable 1 and the second pulley 4, the distance between the second pulley 4 and the first pulley 3, and the distance between the first pulley 3 and the winch mechanism 5 gradually increases.

[0043] Specifically, the angle between the luffing mast 2 and the basic arm is β. When the angle between the luffing mast 2 and the basic arm is β, the sum of the distance between the first end of the superlift cable 1 and the second pulley 4, the distance between the second pulley 4 and the first pulley 3, and the distance between the first pulley 3 and the winch mechanism 5 is recorded as m.

[0044] Taking the distance between the first end of the superlift cable 1 and the first end of the luffing mast 2 as 80 meters, the distance between the hoisting mechanism 5 and the first end of the luffing mast 2 as 3 meters, the distance between the second pulley 4 and the hoisting mechanism 5 as 5 meters, and the distance between the luffing mast 2 and the first pulley 3 as 10 meters as an example, the corresponding relationship between m and β during the change of β is shown in the table below.

[0045] β / (degrees) m / (meters) 097.01097.52098.53099.640100.750101.660102.370102.980103.490103.6

[0046] In an embodiment of the present application, after receiving the super-lift cable pre-tensioning instruction, it is necessary to first adjust the angle between the variable-length mast 2 and the basic arm to a first preset angle α, and the first preset angle α is greater than or less than 90 degrees, that is, the variable-length mast 2 is not perpendicular to the basic arm.

[0047] While adjusting the angle between the luffing mast 2 and the basic arm, the hoisting mechanism 5 is used to adjust the retraction amount of the super-lifting cable 1 to pre-tension the super-lifting cable 1 to prevent it from being too loose.

[0048] In this embodiment, pre-tensioning refers to adjusting the retraction and extension amount of the super-lift cable 1 so that the super-lift cable 1 is in a state that is neither too tight nor too loose. In other words, the length of the super-lift cable 1 that is not retracted is slightly larger than the sum of the distances of the path passed by the super-lift cable 1.

[0049] After adjusting the position of the luffing mast 2, the hoisting mechanism 5 is locked to ensure that the length of the super-lift cable 1 between the hoisting mechanism 5 and the end boom is fixed, that is, the length of the super-lift cable 1 released by the hoisting mechanism 5 remains unchanged. The luffing mast 2 is then rotated in a direction that makes the luffing mast 2 and the boom tend to be perpendicular. As the luffing mast 2 rotates, the sum of the distance between the first end of the super-lift cable 1 and the second pulley 4, the distance between the second pulley 4 and the first pulley 3, and the distance between the first pulley 3 and the hoisting mechanism 5 gradually increases. Since the length of the super-lift cable 1 released by the hoisting mechanism 5 remains unchanged, the super-lift cable 1 will gradually tighten during the rotation of the luffing mast 2, generating a certain tension, thereby completing the pre-tightening of the super-lift cable 1.

[0050] It should be understood that in the pre-tensioned state, the super-lift cable 1 is substantially straightened, but not fully stretched. After the hoisting mechanism 5 is locked, as the luffing mast 2 rotates, the length of the super-lift cable 1 gradually approaches or even slightly decreases from the length of the path it passes through, straightening and tensioning the super-lift cable 1. In other words, the tension in the pre-tensioned super-lift cable 1 is less than the tension in the tensioned state.

[0051] With such an arrangement, when the super-lift cable 1 is pre-tightened using the pre-tightening method of the super-lift cable provided in the embodiment of the present application, it does not rely solely on the pulling force of the winch mechanism 5. The pre-tightening amount of the super-lift cable 1 is cleverly increased by the rotation of the variable-length mast 2, and the pre-tightening force that can be provided by the hydraulic cylinder for driving the variable-length mast 2 to change its length is fully utilized, which is conducive to maximizing the lifting performance of the crane and solves the problem of insufficient pre-tightening when the super-lift winch is used to pre-tighten the super-lift cable 1 in the prior art.

[0052] Furthermore, the method for pre-tightening the superlift cable provided herein does not require additional drive devices during the operation after locking the hoisting mechanism 5. This method utilizes only the adjustment mechanism already in place in the superlift device for driving the luffing mast 2, resulting in a simple structure and low cost. Furthermore, the pre-tightening of the superlift cable 1 is completed during the luffing process of the luffing mast 2, reducing the number of operational steps.

[0053] In some embodiments, when the luffing mast is at a target position, a difference between an inclination angle of the base boom and an inclination angle of the distal boom reaches a target difference.

[0054] The base boom's inclination angle is the angle it makes relative to the horizontal, while the distal boom's inclination angle is the angle it makes relative to the horizontal. The greater the difference between the base and distal boom angles, the greater the degree of boom bending; the smaller the difference, the less the boom bending.

[0055] That is, when the superlift cable 1 is pre-tightened, the boom needs to be controlled to a certain bending degree.

[0056] In step 130 , the difference between the inclination angle of the basic arm and the inclination angle of the end arm needs to be obtained in real time, and the rotation of the variable mast 2 is controlled according to the difference between the inclination angle of the basic arm and the inclination angle of the end arm to provide an appropriate preload for the superlift cable 1 .

[0057] Due to the lateral deflection of the boom, the difference between the inclination angle of the base boom and the inclination angle of the end boom is relatively large before the super-lift cable 1 is tensioned. When the super-lift cable 1 is pre-tightened by rotating the luffing mast 2, before the luffing mast 2 rotates to be perpendicular to the boom, the super-lift cable 1 is gradually tightened as the luffing mast 2 rotates. At the same time, the difference between the inclination angles of the base boom and the end boom gradually decreases, that is, the degree of bending of the boom gradually decreases. When pre-tightening the super-lift cable 1, it is sufficient to keep the difference between the inclination angles of the base boom and the end boom within a certain range.

[0058] When the difference between the inclination angles of the basic boom and the distal boom is reduced to a target difference, a rotation stop signal is sent to control the luffing mast 2 to stop rotating, thereby completing the pre-tightening of the superlift cable 1 .

[0059] In a specific embodiment, the absolute value of the target difference is less than or equal to 2 degrees, that is, the difference between the inclination angle of the basic arm and the inclination angle of the end arm is controlled within a range of -2 degrees to 2 degrees.

[0060] In this embodiment, to determine the difference between the inclination angles of the base arm and the end arm, it is necessary to determine a first inclination angle of the base arm relative to the horizontal and a second inclination angle of the end arm relative to the horizontal. The difference between the inclination angles of the base arm and the end arm can then be determined based on the first and second inclination angles.

[0061] The first tilt angle and the second tilt angle can be obtained by respectively setting tilt sensors at one end of the base arm away from the end arm and at another end of the end arm away from the base arm, and measuring them using the tilt sensors.

[0062] In some embodiments, when the luffing mast 2 is in the target position, the luffing mast 2 is perpendicular to the boom. That is, in step 130, the luffing mast 2 can be directly rotated to the position where the luffing mast 2 is perpendicular to the boom, thereby providing maximum pretension to the superlift cable 1.

[0063] In this case, if the pre-tensioning amount of the super-lift cable 1 is too large when the luffing mast 2 is rotated to a position perpendicular to the boom, re-pre-tensioning is required, and the value of the first preset angle α is appropriately increased in step 120. If the pre-tensioning amount of the super-lift cable 1 is insufficient when the luffing mast 2 is rotated to a position perpendicular to the boom, re-pre-tensioning is required, and the value of the first preset angle α is appropriately reduced in step 120.

[0064] In this embodiment of the present application, before controlling the luffing mast 2 to rotate relative to the base boom and controlling the hoisting mechanism 5 to adjust the retraction and extension of the super-lift cable 1 in accordance with the super-lift cable pre-tensioning instruction, that is, before step 120, it is also necessary to control the boom to rotate until the boom is angled with the horizontal, thereby placing the boom in an inclined state. The angle between the boom and the horizontal is referred to as the second preset angle.

[0065] Before the super-lift cable 1 is pre-tightened using the pre-tightening method for super-lift cables provided in the embodiments of the present application, the degree of boom bending is also affected by the boom's tilt angle. When the boom's tilt angle is small, for example, when the boom's axis is close to horizontal, the degree of boom bending is large; when the boom's tilt angle is large, for example, when the boom's axis is close to vertical, the degree of boom bending is small.

[0066] Therefore, before step 120, when a boom state adjustment signal is issued according to the superlift cable pre-tensioning instruction to adjust the boom tilt angle to a larger value range, the requirement for the pre-tensioning amount of the superlift cable 1 in step 130 can be reduced.

[0067] In this embodiment, the second preset angle is set to 74-80 degrees, that is, the above-mentioned pre-tightening operation is performed when the tilt angle of the boom is adjusted to 74-80 degrees.

[0068] Specifically, the second preset angle may be set to 77 degrees.

[0069] On the other hand, based on the same general inventive concept, an embodiment of the present application further provides a pre-tensioning device for a super-lift cable. The pre-tensioning device for the super-lift cable described below and the pre-tensioning method for the super-lift cable described above can refer to each other.

[0070] In an embodiment of the present application, a pretensioning device for a superlift cable is provided. The superlift cable 1 requires a specific winding arrangement. Specifically, the first end of the luffing mast 2 is rotatably connected to the base boom of the boom. An adjustment mechanism is provided between the luffing mast 2 and the base boom for adjusting the angle between the luffing mast 2 and the base boom. The adjustment mechanism can be, but is not limited to, a hydraulic cylinder 6, the ends of which are rotatably connected to the luffing mast 2 and the base boom, respectively.

[0071] The luffing mast 2 is equipped with a hoisting mechanism 5, and the base boom is equipped with a first winding structure. The first end of the super-lift cable 1 is fixedly connected to the end boom of the boom. The second end of the super-lift cable 1 is connected to the second end of the luffing mast 2 and the first winding structure before being connected to the hoisting mechanism 5. The hoisting mechanism 5 can retract and extend the super-lift cable 1. The first end of the luffing mast 2 is located between the first winding structure and the first end of the super-lift cable 1.

[0072] A second winding structure may be provided at the second end of the luffing mast, and the second winding structure is used to ensure the stability of the superlift cable 1 wound around the second end of the luffing mast 2 .

[0073] The first winding structure and the second winding structure may be, but are not limited to, pulley structures. Referring to FIG. 1 , the first winding structure is the first pulley 3 , and the second winding structure is the second pulley 4 .

[0074] FIG3 is a schematic structural diagram of the pre-tightening device for the super-lift cable provided in the present application.

[0075] As shown in Figure 3, the pre-tensioning device of the superlift cable includes:

[0076] Receiving module 7, used for receiving the super lifting cable pre-tightening instruction;

[0077] a first control module 8, which controls the luffing mast to rotate to a target position inclined relative to the base arm according to the super-lift cable pre-tensioning instruction, and controls the hoisting mechanism to adjust the retraction and extension amount of the super-lift cable to pre-tension the super-lift cable;

[0078] The second control module 9 locks the hoisting mechanism and controls the luffing mast to rotate to a target position in a direction perpendicular to the boom to tension the super-lift cable, wherein the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning.

[0079] On the other hand, based on the same general inventive concept, an embodiment of the present application also provides a crane, including a controller, which can execute the pre-tightening method of the super-lift cable provided in any of the above embodiments, thereby realizing automatic pre-tightening of the super-lift cable 1 and reducing manual operations.

[0080] The crane in the embodiment of the present application includes a boom and a super-lifting device arranged on the boom, and the super-lifting device includes a variable-length mast 2, a hydraulic cylinder 6, a first pulley 3, a second pulley 4, a winch mechanism 5 and a super-lifting cable 1.

[0081] Specifically, the luffing mast 2 is mounted on the base boom of the crane arm, with the first end of the luffing mast 2 pivotally connected to the base boom of the crane arm. A hydraulic cylinder 6 is mounted between the luffing mast 2 and the base boom, with the cylinder body of the hydraulic cylinder 6 pivotally connected to the base boom, and the piston rod of the hydraulic cylinder 6 pivotally connected to the luffing mast 2. The telescopic movement of the hydraulic cylinder 6 adjusts the angle between the luffing mast 2 and the base boom.

[0082] The first pulley 3 is arranged on the basic arm. Specifically, the first pulley 3 can be arranged on an end of the basic arm away from the end arm of the lifting arm.

[0083] The second pulley 4 and the hoisting mechanism 5 are arranged on the luffing mast 2 . The second pulley 4 is arranged at the second end of the luffing mast 2 , and the hoisting mechanism 5 is arranged between the first end of the luffing mast 2 and the second pulley 4 .

[0084] The first end of the super-lift cable 1 is fixedly connected to the distal boom, and the first end of the luffing mast 2 is located between the first pulley 3 and the first end of the super-lift cable 1. The second end of the super-lift cable 1 passes through the second pulley 4 and the first pulley 3 in sequence before being connected to the winch mechanism 5.

[0085] In this embodiment, the crane further includes a first inclination sensor and a second inclination sensor, and both the first inclination sensor and the second inclination sensor are electrically connected to the controller.

[0086] The first inclination sensor is used to detect the angle of the base boom relative to the horizontal line, generate a first inclination signal, and transmit the first inclination signal to the controller. The second inclination sensor is used to detect the angle of the distal boom relative to the horizontal line, generate a second inclination signal, and transmit the second inclination signal to the controller. The controller can control the operation of the hydraulic cylinder 6 based on the received result.

[0087] The device embodiments described above are merely illustrative, and some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. Those skilled in the art may understand and implement the present invention without inventive effort.

[0088] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for pre-tightening a super-lift cable, wherein the first end of the super-lift cable (1) is fixedly connected to the last arm of a crane arm, the crane arm is provided with a luffing mast (2), the first end of the luffing mast (2) is rotatably connected to the basic arm of the crane arm, a hoisting mechanism (5) is provided on the luffing mast (2), the second end of the super-lift cable (1) is connected to the hoisting mechanism (5) after winding around the second end of the luffing mast (2) and a first winding structure fixed to the basic arm in sequence, the first end of the luffing mast (2) is located between the first winding structure and the first end of the super-lift cable (1), the method for pre-tightening the super-lift cable comprising: Receive the super-lift cable pre-tightening instruction; According to the super-lift cable pre-tensioning instruction, the luffing mast (2) is controlled to rotate to a target position inclined relative to the basic arm, and the hoisting mechanism (5) is controlled to adjust the retraction and extension amount of the super-lift cable (1) so that the super-lift cable (1) is pre-tensioned; The hoisting mechanism (5) is locked, and the luffing mast (2) is controlled to rotate to a target position in a direction tending to be perpendicular to the boom, so that the super-lift cable (1) is tensioned, wherein the tension of the super-lift cable (1) during pre-tensioning is less than the tension during tensioning.

2. The method for pre-tightening a superlift cable according to claim 1, wherein: When the luffing mast (2) is at the target position, the difference between the inclination angle of the basic arm and the inclination angle of the terminal arm reaches a target difference value.

3. The method for pre-tightening a superlift cable according to claim 2, wherein: The step of obtaining the difference between the inclination angle of the basic arm and the inclination angle of the end arm comprises: Acquire a first inclination angle of the basic arm relative to a horizontal line and a second inclination angle of the terminal arm relative to the horizontal line; The difference between the inclination angle of the basic arm and the inclination angle of the end arm is determined according to the first inclination angle and the second inclination angle.

4. The method for pre-tightening a superlift cable according to claim 2, wherein: The absolute value of the target difference is less than or equal to 2 degrees.

5. The method for pre-tightening a superlift cable according to any one of claims 1 to 4, wherein: When the luffing mast is at the target position, the luffing mast (2) is perpendicular to the boom.

6. The method for pre-tightening a superlift cable according to any one of claims 1 to 5, wherein: Before controlling the luffing mast (2) to rotate relative to the basic arm to a target position inclined relative to the basic arm, the method further comprises: According to the super-lift cable pre-tightening instruction, the boom is controlled to rotate until the boom is inclined relative to the horizontal line.

7. The method for pre-tightening a superlift cable according to any one of claims 1 to 6, wherein: The angle between the crane arm and the horizontal line is 74-80 degrees.

8. A pre-tensioning device for a super-lift cable, wherein the first end of the super-lift cable (1) is fixedly connected to the last arm of a crane boom, the crane boom is provided with a luffing mast (2), the first end of the luffing mast (2) is rotatably connected to the basic arm of the crane boom, a hoisting mechanism (5) is provided on the luffing mast (2), the second end of the super-lift cable (1) is connected to the hoisting mechanism (5) after winding around the second end of the luffing mast (2) and a first winding structure fixed to the basic arm in sequence, the first end of the luffing mast (2) is located between the first winding structure and the first end of the super-lift cable (1), the pre-tensioning device for the super-lift cable comprises: A receiving module (7), used for receiving an instruction for pre-tightening the super-lift cable; A first control module (8) is used to control the luffing mast (2) to rotate to a target position inclined relative to the basic arm according to the super-lift cable pre-tensioning instruction, and to control the hoisting mechanism (5) to adjust the retraction and extension amount of the super-lift cable (1) so that the super-lift cable (1) is pre-tensioned; The second control module (9) is used to lock the hoisting mechanism (5) and control the luffing mast (2) to rotate to a target position in a direction tending to be perpendicular to the lifting arm, so as to tension the super-lift cable (1), wherein the tension of the super-lift cable (1) during pre-tensioning is less than the tension during tensioning.

9. A crane, comprising a controller, wherein the controller is adapted to execute the method for pre-tensioning a superlift cable according to any one of claims 1 to 7.

10. The crane according to claim 9, wherein: The crane also includes: a first inclination sensor, adapted to collect the angle of the basic arm relative to the horizontal line, obtain a first inclination signal, and send the first inclination signal to the controller; The second inclination sensor is adapted to collect the angle of the distal arm relative to the horizontal line, obtain a second inclination signal, and send the second inclination signal to the controller.

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