Pre-tightening method of super-lifting cable, super-lifting device and crane

Abstract

The application relates to the technical field of hoisting equipment, and provides a pre-tightening method of an ultra-lifting cable, an ultra-lifting device and a crane. The pre-tightening method of the ultra-lifting cable comprises the following steps: receiving an ultra-lifting cable pre-tightening instruction; according to the ultra-lifting cable pre-tightening instruction, a variable-amplitude mast is controlled to rotate to a position inclined relative to a basic arm, and a winch mechanism is controlled to adjust the winding and unwinding amount of the ultra-lifting cable, so that the ultra-lifting cable is pre-tensioned; the winch mechanism is locked, and the variable-amplitude mast is controlled to rotate to a target position in a direction tending to be perpendicular to the lifting arm, so that the ultra-lifting cable is tensioned, wherein the tension of the ultra-lifting cable when pre-tensioned is smaller than the tension when tensioned. In this way, the problem of insufficient pre-tightening amount when the ultra-lifting cable is pre-tensioned by the ultra-lifting winch in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of lifting equipment technology, and in particular to a method for pre-tensioning superlift cables, a superlift device, and a crane. Background Technology

[0002] As cranes have evolved, jib designs have become increasingly longer. However, the height and width dimensions of the jib's cross-section are limited by various factors, resulting in a higher slenderness ratio. This leads to increased lateral deflection and decreased rigidity of the jib, thus restricting the crane's lifting capacity. Cranes with long jib lengths typically employ superlift devices to address these issues. Superlift devices pre-tension the superlift cables, but different pre-tension amounts can affect lifting performance.

[0003] Currently, super-lift winches are generally used to pre-tighten super-lift cables. When using a super-lift winch for pre-tightening, the cable is primarily pre-tightened using the winch's tension, and then the winch is locked by a ratchet. However, because the tension provided by a super-lift winch is relatively small, the amount of pre-tightening the cable is limited. This is insufficient for crane booms with large lateral deflections.

[0004] Therefore, how to solve the problem of insufficient pretension when using a super-lift winch to pre-tighten the super-lift cable in the existing technology has become an important technical problem to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a pre-tensioning method for super-lift cables, a super-lift device, and a crane, to solve the defect of insufficient pre-tensioning amount when using a super-lift winch to pre-tension super-lift cables in the prior art.

[0006] This invention provides a method for pre-tensioning a super-lift cable. The first end of the super-lift cable is fixedly connected to the end section of a lifting boom. A luffing mast is mounted on the lifting boom. The first end of the luffing mast is rotatably connected to the base section of the lifting boom. A winch mechanism is mounted on the luffing mast. The second end of the super-lift cable passes sequentially around the second end of the luffing mast and a first winding structure fixed to the base section before connecting to the winch mechanism. The first end of the luffing mast is located between the first winding structure and the first end of the super-lift cable. The method for pre-tensioning the super-lift cable includes:

[0007] Receive the pretensioning command for the lifting cable;

[0008] According to the super-lift cable pretensioning command, control the luffing mast to rotate to a position tilted relative to the basic boom, and control the winch mechanism to adjust the take-up and release amount of the super-lift cable to pretension the super-lift cable;

[0009] Lock the hoisting mechanism and control the luffing mast to rotate to the target position in a direction that is 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.

[0010] According to a pre-tensioning method for a boom cable provided by the present invention, when the luffing mast is in the target position, the difference between the tilt angle of the main boom and the tilt angle of the end boom reaches the target difference value.

[0011] According to a pre-tensioning method for a super-lift cable provided by the present invention, the step of obtaining the difference between the tilt angle of the base arm and the tilt angle of the end arm includes:

[0012] Obtain the first tilt angle of the basic arm relative to the horizontal line and the second tilt angle of the end arm relative to the horizontal line;

[0013] The difference between the tilt angle of the basic arm and the tilt angle of the end arm is determined based on the first tilt angle and the second tilt angle.

[0014] According to the pre-tensioning method of the super-lift cable provided by the present invention, the absolute value of the target difference is less than or equal to 2 degrees.

[0015] According to a pre-tensioning method for a super-lift cable provided by the present invention, when the luffing mast is in the target position, the luffing mast is perpendicular to the lifting boom.

[0016] According to a pre-tensioning method for a boom cable provided by the present invention, before controlling the luffing mast to rotate to a position tilted relative to the base boom, the method further includes:

[0017] According to the pre-tensioning command of the lifting cable, the lifting arm is controlled to rotate until the lifting arm is tilted relative to the horizontal line.

[0018] According to the pre-tensioning method of the super-lift cable provided by the present invention, the included angle between the lifting arm and the horizontal line is 74-80 degrees.

[0019] The present invention 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 end section of the lifting boom, the lifting boom is provided with a luffing mast, the first end of the luffing mast is rotatably connected to the base boom of the lifting boom, a winch mechanism is provided on the luffing mast, the second end of the super-lift cable passes sequentially around the second end of the luffing mast and a first winding structure fixed to the base boom before being connected to the winch mechanism, 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 includes:

[0020] The receiving module is used to receive the pretensioning command for the lifting cable;

[0021] The first control module is used to control the luffing mast to rotate to a position tilted relative to the basic boom according to the super-lift cable pretensioning command, and to control the hoisting mechanism to adjust the take-up and release amount of the super-lift cable so that the super-lift cable is pre-tensioned.

[0022] The second control module is used to lock the hoisting mechanism and control the luffing mast to rotate to the target position in a direction that is 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.

[0023] The present invention also provides a crane including a controller adapted to perform the above-described method for pre-tensioning the lifting cable.

[0024] A crane according to the present invention further includes:

[0025] The first tilt sensor is adapted to acquire the angle between the basic arm and the horizontal line, obtain the first tilt signal, and send the first tilt signal to the controller;

[0026] The second tilt sensor is adapted to acquire the angle between the end arm and the horizontal line, obtain a second tilt signal, and send the second tilt signal to the controller.

[0027] In the pre-tensioning method for the super-lift cable provided by this invention, when pre-tensioning the super-lift cable, it is necessary to first adjust the angle between the luffing mast and the main boom so that the luffing mast and the main boom are relatively tilted. While adjusting the angle between the luffing mast and the main boom, the winch mechanism is used to raise and lower the super-lift cable to pre-tension it and prevent it from becoming too slack. After adjusting the position of the luffing mast, the winch mechanism is locked to ensure that the length of the super-lift cable located between the winch mechanism and the final boom section is fixed, that is, the length of the super-lift cable released by the winch mechanism remains unchanged. Then, the luffing mast is rotated in a direction that makes the luffing mast and the boom more perpendicular. As the luffing mast rotates, the sum of the distances between the first end of the super-lift cable and the second winding structure, the distance between the second winding structure and the first winding structure, and the distance between the first winding structure and the winch mechanism gradually increases. Since the length of the super-lift cable released by the winch mechanism remains constant, the super-lift cable will gradually tighten during the rotation of the luffing mast and generate a certain tension force, thereby completing the pre-tensioning of the super-lift cable.

[0028] When pre-tightening the superlift cable using the pre-tightening method provided by this invention, it does not rely solely on the pulling force of the winch mechanism. Instead, it cleverly increases the pre-tightening amount of the superlift cable by rotating the luffing mast. This fully utilizes the pre-tightening force provided by the hydraulic cylinder used to drive the luffing mast, thus solving the problem of insufficient pre-tightening amount when using a superlift winch to pre-tighten the superlift cable in the prior art. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the super-lift device provided by the present invention;

[0031] Figure 2 This is a flowchart of the pre-tensioning method for the super-lift cable provided by the present invention.

[0032] Figure label:

[0033] 1. Overhead cable; 2. Luffing mast; 3. First pulley; 4. Second pulley; 5. Winching mechanism; 6. Hydraulic cylinder; α. First preset angle. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] The following is combined with Figures 1 to 2 The present invention describes a method for pre-tensioning the super-lift cable.

[0037] like Figure 1 and Figure 2 As shown in the embodiment of the present invention, in the pre-tensioning method of the super-lift cable, the super-lift cable 1 needs to have a certain winding method. Specifically, the first end of the luffing mast 2 is rotatably connected to the basic arm of the lifting boom. An adjustment mechanism is provided between the luffing mast 2 and the basic arm to adjust the angle between the luffing mast 2 and the basic arm. The adjustment mechanism can be, but is not limited to, a hydraulic cylinder 6, with both ends of the hydraulic cylinder 6 rotatably connected to the luffing mast 2 and the basic arm, respectively.

[0038] A hoisting mechanism 5 is installed on the luffing mast 2, and a first winding structure is installed on the main boom. The first end of the super-lift cable 1 is fixedly connected to the last section of the boom, and the second end passes through the second end of the luffing mast 2 and the first winding structure before connecting 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.

[0039] A second winding structure can be installed at the second end of the luffing mast. 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.

[0040] The first and second winding structures described above can be, but are not limited to, pulley structures, as shown in the reference. Figure 1 The first winding structure is the first pulley 3, and the second winding mechanism is the second pulley 4.

[0041] like Figure 2 As shown, based on the above structure, the pre-tensioning method for the super-lift cable provided in this embodiment of the invention mainly includes the following steps:

[0042] Step 110: Receive the pretensioning command for the lifting cable;

[0043] Step 120: According to the super-lift cable pretensioning command, control the luffing mast to rotate to a position tilted relative to the basic boom, and control the winch mechanism to adjust the take-up and release amount of the super-lift cable to pre-tension the super-lift cable.

[0044] Step 130: Lock the winch mechanism and control the luffing mast to rotate to the target position in a direction that is 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.

[0045] First, through extensive data analysis and verification, the applicant discovered that when the luffing mast 2 rotates in a direction away from the boom, that is, when the luffing mast 2 gradually rotates towards a direction that is more perpendicular to the boom, the sum of the distance between the first end of the lifting 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.

[0046] 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 lifting 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 is denoted as m.

[0047] Taking the distance between the first end of the super-lift cable 1 and the first end of the luffing mast 2 as 80 meters, the distance between the winch mechanism 5 and the first end of the luffing mast 2 as 3 meters, the distance between the second pulley 4 and the winch 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 correspondence between m and β during the change of β is shown in the table below.

[0048] 0 97.0 10 97.5 20 98.5 30 99.6 40 100.7 50 101.6 60 102.3 70 102.9 80 103.4 90 103.6

[0049] In this embodiment of the invention, after receiving the pretensioning command for the luffing cable, it is necessary to first adjust the angle between the luffing mast 2 and the basic arm to a first preset angle α. The first preset angle α is greater than or less than 90 degrees, that is, the luffing mast 2 and the basic arm are not perpendicular.

[0050] While adjusting the angle between the luffing mast 2 and the basic boom, the hoisting mechanism 5 is used to adjust the amount of take-up and take-down of the super-lift cable 1 to pre-tension the super-lift cable 1 and prevent it from becoming too slack.

[0051] In this embodiment, pre-tensioning refers to adjusting the amount of tensioning and loosening of the super-lift cable 1 so that the super-lift cable 1 is neither too taut nor too slack. In other words, the length of the super-lift cable 1 that is not retracted is slightly greater than the sum of the distances along the path traveled by the super-lift cable 1.

[0052] After adjusting the position of the luffing mast 2, lock the winch mechanism 5 to ensure that the length of the super-lift cable 1 between the winch mechanism 5 and the last section of the boom is fixed, that is, the length of the super-lift cable 1 released by the winch mechanism 5 remains unchanged. Then rotate the luffing mast 2 in a direction that makes the luffing mast 2 more perpendicular to the boom. 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 winch mechanism 5 gradually increases. Since the length of the super-lift cable 1 released by the winch mechanism 5 remains unchanged, the super-lift cable 1 will gradually tighten during the rotation of the luffing mast 2, generating a certain tension force, thereby completing the pre-tensioning of the super-lift cable 1.

[0053] It should be understood that, in the pre-tensioned state, the super-lift cable 1 is basically straight, but not fully tensioned. After the winch mechanism 5 is locked, as the luffing mast 2 rotates, the length of the super-lift cable 1 gradually approaches or is even slightly less than the length of the path it travels, causing the super-lift cable 1 to be straightened and tensioned. That is, the tension of the super-lift cable 1 during pre-tension is less than the tension during tension.

[0054] With this configuration, when pre-tightening the super-lift cable 1 using the pre-tightening method provided in this embodiment of the invention, it does not rely solely on the pulling force of the winch mechanism 5. Instead, the pre-tightening amount of the super-lift cable 1 is cleverly increased by rotating the luffing mast 2. This fully utilizes the pre-tightening force provided by the hydraulic cylinder used to drive the luffing mast 2, which is beneficial for maximizing the lifting performance of the crane and solves the problem of insufficient pre-tightening amount when using a super-lift winch to pre-tighten the super-lift cable 1 in the prior art.

[0055] Furthermore, in the pre-tensioning method for the super-lift cable provided by this invention, no additional driving device is required in the operation after locking the winch mechanism 5. It can be completed using only the existing adjustment mechanism of the super-lift device used to drive the luffing mast 2 to change its luffing position, which has the advantages of simple structure and low cost. Moreover, the pre-tensioning of the super-lift cable 1 is completed during the luffing process of the luffing mast 2, reducing the number of operation steps.

[0056] In some embodiments, when the luffing mast is in the target position, the difference between the tilt angle of the main boom and the tilt angle of the end boom reaches the target difference value.

[0057] The tilt angle of the main boom is the angle between the main boom and the horizontal line, and the tilt angle of the end boom is the angle between the end boom and the horizontal line. The greater the difference between the tilt angles of the main boom and the end boom, the greater the degree of bending of the boom; the smaller the difference between the tilt angles of the main boom and the end boom, the less the degree of bending of the boom.

[0058] That is, when pre-tensioning the super-lift cable 1, the boom needs to be controlled at a certain degree of bending.

[0059] In step 130, it is necessary to obtain the difference between the tilt angle of the basic boom and the tilt angle of the end boom in real time, and control the rotation of the luffing mast 2 based on the difference between the tilt angle of the basic boom and the tilt angle of the end boom to provide a suitable preload to the super-lift cable 1.

[0060] Due to its own lateral deflection, the difference between the tilt angle of the main boom and the tilt angle of the final boom is significant before the super-lift cable 1 is tensioned. When the super-lift cable 1 is pre-tensioned by rotating the luffing mast 2, before the luffing mast 2 rotates to be perpendicular to the boom, the super-lift cable 1 gradually tensions as the luffing mast 2 rotates. Simultaneously, the difference between the tilt angles of the main boom and the final boom gradually decreases, meaning the degree of boom bending gradually decreases. When pre-tensioning the super-lift cable 1, the difference between the tilt angles of the main boom and the final boom should be kept within a certain range.

[0061] When the difference between the tilt angle of the main boom and the tilt angle of the end boom decreases to the target difference value, a stop rotation signal can be sent to control the luffing mast 2 to stop rotating, thus completing the pre-tensioning of the super-lift cable 1.

[0062] In a specific embodiment, the absolute value of the above-mentioned target difference is less than or equal to 2 degrees, that is, the difference between the tilt angle of the basic arm and the tilt angle of the end arm is controlled within -2 degrees to 2 degrees.

[0063] In this embodiment, when obtaining the difference between the tilt angle of the base arm and the tilt angle of the end arm, it is necessary to obtain the first tilt angle of the base arm relative to the horizontal line and the second tilt angle of the end arm relative to the horizontal line. Then, based on the first and second tilt angles, the difference between the tilt angle of the base arm and the tilt angle of the end arm can be determined.

[0064] The first tilt angle and the second tilt angle mentioned above can be obtained by setting tilt angle sensors at the end of the main arm away from the end arm and at the end of the end arm away from the main arm, respectively, and measuring them using the tilt angle sensors.

[0065] In some embodiments, when the luffing mast 2 is in the target position, it is perpendicular to the boom. That is, in step 130, the luffing mast 2 can be directly rotated to a position where it is perpendicular to the boom, providing the maximum preload to the super-lift cable 1.

[0066] In this situation, if the preload on the super-lift cable 1 is too high when the luffing mast 2 is rotated to a position perpendicular to the boom, it needs to be re-tightened, and the value of the first preset angle α is appropriately increased in step 120. If the preload on the super-lift cable 1 is insufficient when the luffing mast 2 is rotated to a position perpendicular to the boom, it needs to be re-tightened, and the value of the first preset angle α is appropriately decreased in step 120.

[0067] In this embodiment of the invention, before controlling the rotation of the luffing mast 2 relative to the basic boom and controlling the winch mechanism 5 to adjust the take-up and release of the luffing cable 1 according to the pre-tensioning command of the super-lift cable, that is, before step 120, it is also necessary to control the boom to rotate until the boom is set at an angle to the horizontal line, so that the boom is in an inclined state. The angle between the boom and the horizontal line is called the second preset angle.

[0068] Before pre-tensioning the super-lift cable 1 using the pre-tensioning method provided in this embodiment of the invention, the degree of bending of the lifting boom is also affected by the tilt angle of the lifting boom itself. When the tilt angle of the lifting boom is small, for example, when the axis of the lifting boom is close to horizontal, the degree of bending of the lifting boom is large; when the tilt angle of the lifting boom is large, for example, when the axis of the lifting boom is close to vertical, the degree of bending of the lifting boom is small.

[0069] Therefore, before step 120, when a crane boom state adjustment signal is issued according to the super-lift cable pretensioning command to adjust the crane boom tilt angle to a larger range, the requirement for the pretension amount of super-lift cable 1 in step 130 can be reduced.

[0070] In this embodiment, the second preset angle is set to 74-80 degrees. That is, the above pre-tightening operation is performed when the tilt angle of the crane arm is adjusted to 74-80 degrees.

[0071] Specifically, the second preset angle can be set to 77 degrees.

[0072] On the other hand, based on the same general inventive concept, the embodiments of the present invention also provide 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 be referred to in correspondence with each other.

[0073] This invention provides a pre-tensioning device for a superlift cable. The superlift cable 1 needs to have a specific winding method. Specifically, the first end of the luffing mast 2 is rotatably connected to the basic arm of the lifting boom. An adjustment mechanism is provided between the luffing mast 2 and the basic arm to adjust the angle between them. The adjustment mechanism can be, but is not limited to, a hydraulic cylinder 6, with both ends of the hydraulic cylinder 6 rotatably connected to the luffing mast 2 and the basic arm, respectively.

[0074] A hoisting mechanism 5 is installed on the luffing mast 2, and a first winding structure is installed on the main boom. The first end of the super-lift cable 1 is fixedly connected to the last section of the boom, and the second end passes through the second end of the luffing mast 2 and the first winding structure before connecting 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.

[0075] A second winding structure can be installed at the second end of the luffing mast. 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.

[0076] The first winding structure and the second winding structure mentioned above can be, but are not limited to, a pulley structure. Referring to the figure, the first winding structure is a first pulley 3, and the second winding mechanism is a second pulley 4.

[0077] The pretensioning device for the super-lift cable includes:

[0078] The receiving module is used to receive the pretensioning command for the lifting cable;

[0079] The first control module is used to control the luffing mast to rotate to a position tilted relative to the basic boom according to the super-lift cable pretensioning command, and to control the winch mechanism to adjust the take-up and release amount of the super-lift cable so that the super-lift cable is pre-tensioned.

[0080] The second control module is used to lock the winch mechanism and control the luffing mast to rotate to the target position in a direction that is 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.

[0081] On another front, based on the same general inventive concept, the present invention also provides a crane, including a controller, which is capable of executing the pre-tensioning method for the super-lift cable provided in any of the above embodiments, thereby realizing automated pre-tensioning of the super-lift cable 1 and reducing manual operation.

[0082] The crane in this embodiment of the invention includes a boom and a super-lifting device mounted on the boom. The super-lifting device includes a luffing mast 2, a hydraulic cylinder 6, a first pulley 3, a second pulley 4, a winch mechanism 5, and a super-lifting cable 1.

[0083] Specifically, the luffing mast 2 is mounted on the basic boom of the crane boom, with its first end rotatably connected to the basic boom. A hydraulic cylinder 6 is positioned between the luffing mast 2 and the basic boom; the cylinder body of the hydraulic cylinder 6 is rotatably connected to the basic boom, and the piston rod of the hydraulic cylinder 6 is rotatably connected to the luffing mast 2. The extension and retraction of the hydraulic cylinder 6 adjusts the angle between the luffing mast 2 and the basic boom.

[0084] The first pulley 3 is located on the basic boom, specifically at the end of the basic boom that is far from the end section of the boom.

[0085] The second pulley 4 and the winch mechanism 5 are mounted on the luffing mast 2. The second pulley 4 is mounted at the second end of the luffing mast 2, and the winch mechanism 5 is mounted between the first end of the luffing mast 2 and the second pulley 4.

[0086] The first end of the aforementioned super-lift cable 1 is fixedly connected to the last section of the 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 and is then connected to the winch mechanism 5.

[0087] In this embodiment, the crane also includes a first tilt sensor and a second tilt sensor, both of which are electrically connected to the controller.

[0088] The first tilt sensor is used to acquire the angle between the main arm and the horizontal line, obtaining a first tilt signal, which is then sent to the controller. The second tilt sensor is used to acquire the angle between the end arm and the horizontal line, obtaining a second tilt signal, which is also sent to the controller. The controller can control the hydraulic cylinder 6 to operate based on the received results.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for pre-tensioning a super-lift cable, characterized in that, The first end of the super-lift cable is fixedly connected to the end section of the lifting boom. A luffing mast is mounted on the lifting boom. The first end of the luffing mast is rotatably connected to the main boom of the lifting boom. A winch mechanism is mounted on the luffing mast. The second end of the super-lift cable passes sequentially around the second end of the luffing mast and a first winding structure fixed to the main boom before connecting to the winch mechanism. The first end of the luffing mast is located between the first winding structure and the first end of the super-lift cable. The pre-tensioning method of the super-lift cable includes: Receive the pretensioning command for the lifting cable; According to the super-lift cable pretensioning command, control the luffing mast to rotate to the initial position tilted relative to the basic boom, and control the winch mechanism to adjust the take-up and release amount of the super-lift cable to pretension the super-lift cable; Lock the winch mechanism to fix the length of the super-lift cable released by the winch mechanism; and control the luffing mast to rotate from the initial position to a target position in a direction that is approximately perpendicular to the boom. The difference between the tilt angle of the main boom and the tilt angle of the end boom reaches a target value. When the difference between the tilt angle of the main boom and the tilt angle of the end boom decreases to the target value, a stop rotation signal is sent to control the luffing mast to stop rotating, thus completing the pre-tensioning of the super-lift cable; wherein the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning. The step of obtaining the difference between the tilt angle of the basic arm and the tilt angle of the end arm includes: obtaining a first tilt angle of the basic arm relative to the horizontal line and a second tilt angle of the end arm relative to the horizontal line. The difference between the tilt angle of the basic arm and the tilt angle of the end arm is determined based on the first tilt angle and the second tilt angle.

2. The pre-tensioning method for the super-lift cable according to claim 1, characterized in that, The absolute value of the target difference is less than or equal to 2 degrees.

3. The pre-tensioning method for the super-lift cable according to claim 1, characterized in that, When the luffing mast is in the target position, the luffing mast is perpendicular to the lifting boom.

4. The pre-tensioning method for the super-lift cable according to claim 1, characterized in that, Before controlling the luffing mast to rotate to a position tilted relative to the basic boom, the method further includes: According to the pre-tensioning command of the lifting cable, the lifting arm is controlled to rotate until the lifting arm is tilted relative to the horizontal line.

5. The pre-tensioning method for the super-lift cable according to claim 4, characterized in that, The angle between the crane boom and the horizontal line is 74-80 degrees.

6. A pre-tensioning device for a super-lift cable, characterized in that, The first end of the super-lift cable is fixedly connected to the end section of the lifting boom. A luffing mast is mounted on the lifting boom. The first end of the luffing mast is rotatably connected to the main boom of the lifting boom. A winch mechanism is mounted on the luffing mast. The second end of the super-lift cable passes sequentially around the second end of the luffing mast and a first winding structure fixed to the main boom before connecting to the winch mechanism. The first end of the luffing mast is located between the first winding structure and the first end of the super-lift cable. The pre-tensioning device for the super-lift cable includes: The receiving module is used to receive the pretensioning command for the lifting cable; The first control module is used to control the luffing mast to rotate to a position tilted relative to the basic boom according to the super-lift cable pretensioning command, and to control the hoisting mechanism to adjust the take-up and release amount of the super-lift cable so that the super-lift cable is pre-tensioned. The second control module is used to lock the winch mechanism, so that the length of the super-lift cable released by the winch mechanism remains constant; and to control the luffing mast to rotate in a direction that is perpendicular to the boom to a target position, such that the difference between the tilt angle of the main boom and the tilt angle of the end boom reaches a target difference value. When the difference between the tilt angle of the main boom and the tilt angle of the end boom decreases to the target difference value, a stop rotation signal is sent to control the luffing mast to stop rotating, thus completing the pre-tensioning of the super-lift cable; wherein, the tension of the super-lift cable during pre-tensioning is less than the tension during tensioning. The step of obtaining the difference between the tilt angle of the basic arm and the tilt angle of the end arm includes: obtaining a first tilt angle of the basic arm relative to the horizontal line and a second tilt angle of the end arm relative to the horizontal line. The difference between the tilt angle of the basic arm and the tilt angle of the end arm is determined based on the first tilt angle and the second tilt angle.

7. A crane, characterized in that, Includes a controller adapted to perform the pretensioning method for the super-lift cable as described in any one of claims 1-5; Also includes: The first tilt sensor is adapted to acquire the angle between the basic arm and the horizontal line, obtain the first tilt signal, and send the first tilt signal to the controller; The second tilt sensor is adapted to acquire the angle between the end arm and the horizontal line, obtain a second tilt signal, and send the second tilt signal to the controller.

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