A method for hoisting a tripod using a sling

Abstract

The present application provides a kind of method for hoisting tripod with sling, including tripod, the tripod includes front support rod and rear pull rod, tripod is set on crane slewing platform, hoist tripod using hoisting device, the hoisting device includes front hook, rear hook and sling, specific steps include: front support rod is connected with rear pull rod;Sling one end is connected with the front support rod sling connection position, the other end of sling is connected with the rear pull rod sling connection position;Rear hook operates, pulls up the front support rod close to the side of sling, so that sling is in straight state;Front hook and rear hook operate in coordination, pull up the front support rod close to the side of front hook, so that rear pull rod is in vertical state;Front hook and rear hook operate together, move front support rod and rear pull rod to above slewing platform;Front support rod and rear pull rod are connected with corresponding position of slewing platform, it is convenient to operate and safe and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crane tripod equipment, and particularly relates to a method for hoisting a tripod by using a sling. BACKGROUND

[0002] The tripod, as a component for assisting rope winding and balancing force on a crane, plays a key role in the crane. The tripod generally needs to be installed on a rotating platform. The tripod includes a vertical rod and an inclined rod. When installing a tripod on a ship crane, in order to avoid the tripod from deviating from the installation position and thus failing to be installed when the tripod is hoisted to the installation position, a suitable hoisting point and hoisting method need to be selected, so that the position of the vertical rod or the inclined rod can be adjusted to eliminate the assembly error when the tripod is hoisted, and the tripod can be normally installed on the rotating platform.

[0003] A method for assembling a crane tripod is disclosed in a patent document with the patent application number 201811120504.1 and the publication date of May 4, 2021. The first portal frame and the second portal frame are assembled on the rotating platform. Then the main cross rod is assembled between the first portal frame and the second portal frame. The third cross rod is assembled between the first inclined rod and the second inclined rod. Finally, two or more auxiliary cross rods are assembled between the first vertical rod and the second vertical rod, and the auxiliary vertical rod and the inclined rod are assembled between the adjacent two auxiliary cross rods. The first cross rod is assembled between the first vertical rod and the first inclined rod by using the segmented first cross rod connected by flanges. The main cross rod and the third cross rod are also assembled by using the segmented cross rod connected by flanges. This assembly method can prevent the first cross rod, the main cross rod and the third cross rod from being normally assembled due to production errors and assembly errors, and has good stability.

[0004] In the above document, the tripod is pre-assembled on the rotating platform before leaving the factory. After assembly, marks are made on each component, and the bolts and nuts between the flanges are removed. At the installation site, the tripod can be assembled according to the marks. This way of assembling the tripod avoids the problem that the assembly position deviates from the preset position after the tripod is hoisted to the rotating platform. However, the tripod needs to be pre-assembled on the rotating platform to determine the assembly position of the tripod, which increases the time for assembling the tripod. In addition, in order to ensure that the inclined strut and the rear connecting rod are arranged at a certain angle, a connecting rod needs to be arranged between the inclined strut and the rear connecting rod to support the inclined strut and the rear connecting rod. However, during the pre-assembly process, the inclined strut needs to be hoisted by a hoisting tool first, and then the connecting rod is arranged between the inclined strut and the rear connecting rod. The connecting rod also needs to be hoisted by a hoisting tool and then connected by welding or other methods. Therefore, the whole hoisting process is relatively complex, and the cost of hoisting and the connecting rod is relatively high. Moreover, after the connecting rod is connected, if there is a small difference between the installation distance of the installation platform and the distance between the front strut and the rear rod, the connecting rod needs to be reinstalled, which makes the reliability of the whole installation poor. SUMMARY

[0005] The present application provides a method for hoisting a tripod by using a sling, which is convenient to install, low in hoisting cost and high in reliability.

[0006] To achieve the above object, the technical scheme of the present application is as follows: a method for hoisting a tripod by using a sling, the tripod comprising a front support rod and a rear pull rod, the rear end of the front support rod and the rear end of the rear pull rod being connected by a flexible sling, the tripod being hoisted onto a rotary platform by using a hoisting device, the hoisting device comprising a front hook, a rear hook and a sling, and the specific steps comprising:

[0007] S1 presetting the connection position of the front support rod and the rear pull rod, the corresponding hoisting position of the front hook and the rear hook on the front support rod, the sling connection position of the front support rod and the rear pull rod and the length of the rear pull rod; determining the sling parameters according to the distance between the installation position of the front support rod and the installation position of the rear pull rod on the rotary platform;

[0008] S2 connecting the front hook with the front hook position on the front support rod and connecting the rear hook with the rear hook position on the front support rod;

[0009] S3 operating the front hook and the rear hook so that the front end of the front support rod is close to the front end of the rear pull rod and the front support rod and the rear pull rod are inclined to be arranged, and connecting the front end of the front support rod with the front end of the rear pull rod;

[0010] S4 determining the sling according to the sling parameters, connecting one end of the sling with the sling connection position of the front support rod and connecting the other end of the sling with the sling connection position of the rear pull rod;

[0011] S5 operating the rear hook to pull up the front support rod close to the side of the sling, so that the sling is in a straightened state;

[0012] S6 operating the front hook to pull up the front support rod close to the side of the front hook, so that the rear pull rod is in a vertical state; the rear hook keeps the sling in the straightened state;

[0013] S7 operating the front hook and the rear hook together to move the front support rod and the rear pull rod above the rotary platform;

[0014] S8 connecting the front support rod and the rear pull rod with the corresponding positions of the rotary platform.

[0015] The above setting, the tripod is installed on the rotating platform of the ship crane, the rear pull rod is on the deck of the ship, the front hook and the rear hook are connected with the front support rod, the front hook and the rear hook can move the position of the front support rod and adjust the inclination of the front support rod relative to the rear pull rod, then the front end of the front support rod and the rear pull rod is connected, then the sling parameters are determined according to the distance between the front support rod and the rear pull rod on the rotating platform, the sling is determined, then the rear end of the front support rod and the rear pull rod is connected through the flexible sling with the sling parameters, then the front support rod is pulled up on one side through the front hook until the rear pull rod is perpendicular to the deck, and the sling is in a straight state through the rear hook, so that the flexible sling can play the role of the connecting rod between the existing front support rod and the rear pull rod, realize the turning of the tripod, then move the turned tripod above the rotating platform of the crane, and then connect the front support rod and the rear pull rod with the corresponding position of the rotating platform to realize the installation of the tripod. In the whole hoisting process, it is not necessary to hoist and weld the connection between the front support rod and the rear pull rod in advance, so that the installation process is simple, the production cost is reduced, and the reliability of the installation of the tripod is ensured through the front hook and the rear hook during the hoisting process, because the sling is in a straight state through the rear hook, the role of the connecting rod between the front support rod and the rear pull rod is ensured, and the adjustment can be realized by moving the front support rod and the rear pull rod when there is a small difference between the distance between the installation platform and the actual distance between the tripods.

[0016] Further, in step S3, when the front hook and the rear hook move the front support rod above the rear pull rod, the front hook moves to make the front support rod incline towards the side close to the front hook, and the front end of the front support rod is hinged to the front end of the rear pull rod.

[0017] The above setting, when the front hook and the rear hook move the front support rod above the rear pull rod, the front hook continues to move downward, so that the front support rod inclines downward with the position of the rear hook as the fulcrum, so that the front support rod can be connected with the rear pull rod,

[0018] Further, in step S4, the relative distance between the sling connection position of the front support rod and the sling connection position of the rear pull rod is adjusted through the operation of the rear hook, so that the sling can be connected with the front support rod and the rear pull rod respectively.

[0019] The above setting, in step S3, the front support rod inclines downward on the side close to the front hook, and the sling connection position of the front support rod is away from the sling connection position of the rear pull rod, then the sling is installed on the sling connection position of the front support rod and the sling connection position of the rear pull rod to realize the installation of the sling.

[0020] Further, step S6 further includes step S60: the front hook and the rear hook operate together to lift the tripod by a preset distance, and the preset distance is not less than the length of the rear pull rod.

[0021] The above setting is to ensure that the tripod is not in contact with the deck during adjustment of the position and angle of the tripod, and the front hook and the rear hook lift the tripod by a distance of at least the length of the rear pull rod, so that in the subsequent step S6, the tripod is not in contact with the deck during adjustment of the position of the tripod, thereby protecting the overall structure of the tripod.

[0022] Further, in step S6, the front hook is pulled up, the rear hook remains stationary and the sling is in a straightened state, the rear pull rod is observed to be in a vertical state, and the front hook stops rising.

[0023] The above setting is that the front hook is pulled up and the rear hook remains stationary, so that the front support rod is in an inclined state, the rear pull rod is observed to be in a vertical state under the action of its own gravity, and the sling is in a taut state, and the front hook stops rising so that the rear pull rod is in a vertical state.

[0024] Further, in step S7, the front hook and the rear hook operate together to transport the tripod to the slewing platform, and the rear pull rod remains in a vertical state and the sling is in a straightened state.

[0025] The above setting is that the rear pull rod remains in a vertical state during transportation of the tripod by the front hook and the rear hook, so that the rear pull rod remains vertical under the action of its own gravity and the sling remains taut, and the overall structure of the tripod is more secure during hoisting, preventing the front support rod and the rear pull rod from colliding during transportation.

[0026] Further, in step S8, the rear pull rod is first connected to one side of the slewing platform, the rear hook operates, the position of the front support rod is adjusted, and the front support rod is connected to the other side of the slewing platform.

[0027] The above setting is that when the tripod is moved to the corresponding position of the slewing platform, the rear pull rod can be connected to the slewing platform first, and the position of the front support rod can be adjusted by the rear hook after the rear pull rod is connected to the slewing platform, without worrying about the overall balance of the tripod, so that the front support rod can be connected to the slewing platform.

[0028] Further, in step S1, the sling parameters include the length of the sling and the maximum pre-tightening force of the sling, the length of the sling is determined according to the distance between the installation position of the front support rod on the slewing platform and the installation position of the rear pull rod, the distance between the installation position of the sling on the front support rod and the mounting hole on the front support rod, and the included angle between the sling and the straight line passing through the mounting hole on the front support rod and the mounting hole on the rear pull rod, and the maximum pre-tightening force of the sling is determined according to the weight of the rear pull rod, the length of the rear pull rod and the center of gravity.

[0029] The above setting can determine the length and maximum pre-tightening force of the sling according to the installation position of the front support rod and the installation position of the rear pull rod on the slewing platform, which facilitates subsequent control of the sling in a straightened state.

[0030] Furthermore, step S5 also includes: the rear hook operates so that the tension of the sling is not greater than the maximum preload, thereby keeping the sling in a straight state.

[0031] The above settings make it easy to control the slings to be in a straight position. Attached Figure Description

[0032] Figure 1 This is one of the overall structural schematic diagrams of the present invention.

[0033] Figure 2 This is the second schematic diagram of the overall structure of the present invention.

[0034] Figure 3 This is a schematic diagram of the overall structure of the present invention installed on a rotary platform.

[0035] Figure 4 for Figure 1 Enlarged view of point A in the middle.

[0036] Figure 5 for Figure 4 Enlarged view of section B in the middle.

[0037] Explanation of reference numerals: 1-Lifting device; 11-Front hook; 12-Rear hook; 2-Triangle frame; 21-Front support rod; 22-Rear tie rod; 3-Sling; 4-Deck; 5-Slewing platform; Front support rod installation position 61; Rear tie rod installation position 62; Rear tie rod center of gravity position 63; Sling front support rod installation position 64. Detailed Implementation

[0038] like Figures 1-5 As shown, a method for hoisting a tripod using slings is described. The tripod 2 includes a front support rod 21 and a rear tie rod 22. The tripod 2 is hoisted onto a rotating platform using a lifting device 1, which includes a front hook 11, a rear hook 12, and flexible slings 3. The specific steps include:

[0039] S1 presets the connection position of the front support rod 21 and the rear tie rod 22, the corresponding lifting positions of the front hook 11 and the rear hook 12 on the front support rod 21, the connection position of the sling 3 between the front support rod 21 and the rear tie rod 22, and the length of the rear tie rod 22; the parameters of the sling 3 are determined according to the distance between the installation positions of the front support rod 21 and the rear tie rod 22 on the rotary platform 5.

[0040] In this embodiment, the sling parameters include the length of the sling 3 and the maximum preload of the sling 3. The length of the sling 3 is determined based on the distance between the installation positions of the front support rod and the rear tie rod on the rotating platform, the distance between the sling installation position on the front support rod and the mounting hole on the front support rod, and the angle between the sling and the straight line containing the mounting hole on the front support rod and the mounting hole on the rear tie rod. The maximum preload of the sling is determined based on the weight of the rear tie rod, the length of the rear tie rod, and the center of gravity.

[0041] As shown in Figure 4 and 5 The horizontal distance s3 and the vertical distance d1 between the center of the sling front support rod mounting position 64 and the center of the slewing platform front support rod mounting position 61 are measured, the distance s2 between the slewing platform front support rod mounting position and the rear pull rod mounting position is measured, the angle A between the sling and the vertical direction is determined by tan A = s3 / (s2-d1), and the length s4 of the sling is s3 / sin A.

[0042] After confirming the rear pull rod gravity center position 63, the weight g1 of the rear pull rod 22, the length s5 of the rear pull rod 22, and the distance s6 from the gravity center to the center of the rear pull rod mounting position 62, the gravity g2 from the rear pull rod gravity center position 63 to the rear pull rod mounting position 62 is calculated, F1*s5 = g2*(s5-s6), F1 is the vertical direction of the sling on the rear pull rod, and the bearing capacity F of the sling is F1*cos A.

[0043] In another embodiment, the empirical value of the sling can also be measured through multiple tests by presetting the parameters of the slewing platform.

[0044] S2 connects the front hook 11 with the front hook 11 position on the front support rod 21, and connects the rear hook 12 with the rear hook 12 position on the front support rod 21;

[0045] S3 operates the front hook 11 and the rear hook 12 so that the front end of the front support rod 21 is close to the front end of the rear pull rod 22, and the front support rod and the rear pull rod are inclined to connect the front end of the front support rod 21 with the front end of the rear pull rod 22; in this embodiment, the front support rod 21 and the rear pull rod 22 are hinged through the pulley frame.

[0046] S4 determines the sling according to the sling parameters, connects one end of the sling 3 with the sling 3 connection position on the front support rod 21, and connects the other end of the sling 3 with the sling 3 connection position on the rear pull rod 22;

[0047] S5 operates the rear hook 12 to pull up the front support rod 21 close to one side of the sling 3, so that the sling 3 is in a straight state;

[0048] S6 cooperatively operates the front hook 11 and the rear hook 12 to pull up the front support rod 21 close to one side of the front hook 11, so that the rear pull rod 22 is in a vertical state; the rear hook keeps the sling in a straight state;

[0049] S7 operates the front hook 11 and the rear hook 12 together to move the front support rod 21 and the rear pull rod 22 above the slewing platform 5;

[0050] S8 connects the front support rod 21 and the rear pull rod 22 to the corresponding positions of the slewing platform 5, the tripod 2 is installed on the slewing platform 5 of the marine crane, the rear pull rod 22 is placed on the deck 4 of the ship, the front hook 11 and the rear hook 12 are connected to the front support rod 21, the front hook 11 and the rear hook 12 can move the position of the front support rod 21 and adjust the inclination angle of the front support rod 21 relative to the rear pull rod 22, thereby connecting the front support rod 21 and the rear pull rod 22, and then pulling one side of the front support rod 21 through the front hook 11, so that the rear pull rod 22 is in a vertical state relative to the deck 4, the tripod 2 is moved above the slewing platform 5 of the crane, and then the front support rod 21 and the rear pull rod 22 are connected to the corresponding positions of the slewing platform 5.

[0051] In step S3, when the front hook 11 and the rear hook 12 move the front support rod 21 above the rear pull rod 22, the front hook 11 operates to incline the side of the front support rod 21 close to the front hook 11, and connect the front end of the front support rod 21 to the front end of the rear pull rod 22. When the front hook 11 and the rear hook 12 move the front support rod 21 above the rear pull rod 22, the front hook 11 continues to move downward, so that the front support rod 21 inclines downward with the rear hook 12 as the fulcrum, so that the front support rod 21 can be connected to the rear pull rod 22.

[0052] In step S4, the relative distance between the front support rod 21 and the rear pull rod 22 can be adjusted by the operation of the rear hook 12 to connect the sling 3, so that the sling 3 can be connected to the front support rod 21 and the rear pull rod 22 respectively. Because in step S3, the side of the front support rod 21 close to the front hook 11 inclines downward, the sling 3 connection position of the front support rod 21 is away from the sling 3 connection position of the rear pull rod 22, and when the distance between the sling 3 connection position of the front support rod 21 and the sling 3 connection position of the rear pull rod 22 is greater than the length of the sling 3, the rear hook 12 can be moved downward to move the sling 3 connection position of the front support rod 21 close to the sling 3 connection position of the rear pull rod 22, so that one end of the sling 3 is connected to the sling 3 connection position of the front support rod 21, and the other end of the sling 3 is connected to the sling 3 connection position of the rear pull rod 22.

[0053] Step S6 also includes step S60: the front hook 11 and the rear hook 12 operate together to lift the tripod 2 by a predetermined distance, and the predetermined distance is not less than the length of the rear pull rod 22. In order to ensure that the tripod 2 does not contact the deck 4 when adjusting the position and angle of the tripod 2, the front hook 11 and the rear hook 12 lift the tripod 2 by a small distance of at least the length of the rear pull rod 22, so that in the subsequent step S6, the tripod 2 will not contact the deck 4 during the adjustment of the position, thereby protecting the overall structure of the tripod 2.

[0054] As Figure 2As shown, in step S6, the front hook 11 is pulled up, the rear hook 12 remains stationary, the rear pull rod 22 is observed, the rear pull rod 22 is in a vertical state, the front hook 11 stops rising, the front hook 11 is pulled up, the rear hook 12 remains stationary, so that the front support rod 21 and the rear pull rod 22 are in an inclined state, the rear pull rod 22 is observed, so that the rear pull rod 22 remains in a vertical state under the action of its own gravity, and at this time the rear hook 12 makes the sling 3 in a tension state, the front hook 11 stops rising, so that the rear pull rod 22 is in a vertical state.

[0055] In step S7, the front hook 11 and the rear hook 12 operate together to move the tripod 2 transversely to the process of moving to the rotating platform 5, the rear pull rod 22 remains in a vertical state, in the process of transferring the tripod 2 by the front hook 11 and the rear hook 12, the force of the front hook 11 balances the entire weight of the tripod, the rear hook 12 makes the sling in a straight state, so that the rear pull rod does not shake left and right, so that the rear pull rod 22 remains in a vertical state, so that the rear pull rod 22 remains in a vertical state under the action of its own gravity and the sling 3 remains in a tension state, in hoisting, the overall structure of the tripod 2 is more firm, preventing the situation that the front support rod 21 and the rear pull rod 22 collide in the process of transferring.

[0056] As Figure 3 shown, in step S8, the rear pull rod 22 is first connected to one side of the rotating platform 5, the rear hook 12 operates, the position of the front support rod 21 is adjusted, the front support rod 21 is connected to the other side of the rotating platform 5, when the tripod 2 moves to the corresponding position of the rotating platform 5, the rear pull rod 22 can be first connected to the rotating platform 5, after the rear pull rod 22 is connected to the rotating platform 5, the position of the front support rod 21 can be adjusted by the rear hook 12, without worrying about the overall balance of the tripod 2, so that the front support rod 21 can be connected to the rotating platform 5.

[0057] The working principle of the present application is as follows: the tripod 2 is installed on the ship crane rotary platform 5, the rear pull rod 22 is placed on the deck 4 of the ship, the front lifting hook 11 and the rear lifting hook 12 are connected with the front support rod 21, the front lifting hook 11 and the rear lifting hook 12 are operated, the front support rod 21 is moved to the corresponding position of the rear pull rod 22, the front support rod 21 is connected with the rear pull rod 22, one end of the sling 3 is connected with the front support rod 21, the other end of the sling 3 is connected with the rear pull rod 22, the rear lifting hook 12 is operated, the front support rod 21 is pulled up close to one side of the sling 3, so that the sling 3 is in a straight state, the front lifting hook 11 and the rear lifting hook 12 are operated together to lift the tripod 2 by a preset distance, the preset distance is at least the length of the rear pull rod 22, so that the tripod 2 does not contact the deck 4 during the adjustment of the position, thereby protecting the overall structure of the tripod 2, the front lifting hook 11 is pulled up, the rear lifting hook 12 remains stationary, the situation of the rear pull rod 22 is observed, the rear pull rod 22 is in a vertical state and the sling 3 is in a tension state, the front lifting hook 11 stops rising, the front lifting hook 11 and the rear lifting hook 12 are operated together to move the tripod 2 to the rotary platform 5, the rear pull rod 22 remains in a vertical state, the rear pull rod 22 is first connected with one side of the rotary platform 5, the rear lifting hook 12 is operated, the position of the front support rod 21 is adjusted, the front support rod 21 is connected with the other side of the rotary platform 5, the connection is realized through a flexible sling, and it is not necessary to realize the connection of the pull rod between the front support rod and the rear pull rod by hoisting and welding, so that the operation method is simple and the cost is low.

Claims

1. A method for suspending a tripod using slings, the tripod comprising a front support rod and a rear tie rod, characterized in that: The rear ends of the front support rod and the rear end of the rear tie rod are connected by flexible slings. A lifting device is used to hoist the tripod onto the rotating platform. The lifting device includes a front hook, a rear hook, and slings. Specific steps include: S1 presets the connection positions of the front support rod and the rear tie rod, the corresponding lifting positions of the front hook and the rear hook on the front support rod, the connection position of the sling between the front support rod and the rear tie rod, and the length of the rear tie rod; the sling parameters are determined based on the distance between the installation positions of the front support rod and the rear tie rod on the slewing platform. S2 connects the front hook to the front hook position on the front support rod, and the rear hook to the rear hook position on the front support rod; When the S3 front hook and rear hook are in operation, the front end of the front support rod approaches the front end of the rear tie rod, and the front support rod and rear tie rod are tilted to connect the front end of the front support rod with the front end of the rear tie rod. S4 determines the sling according to the sling parameters, and connects one end of the sling to the connection position of the front support rod sling, and the other end of the sling to the connection position of the rear tie rod sling; When the S5 hook is in operation, the front support rod is pulled up to the side of the sling, so that the sling is in a straight state; When the S6 front hook is in operation, the front support rod is pulled up to the side close to the front hook, so that the rear tie rod is in a vertical position; the rear hook keeps the sling in a straight position. The S7 front hook and rear hook work together to move the front support rod and rear tie rod above the slewing platform; S8 connects the front strut and rear tie rod to the corresponding positions on the slewing platform.

2. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S3, when the front hook and the rear hook move the front support rod above the rear tie rod, the front hook operates, causing the front support rod to tilt on the side closer to the front hook, and hinge the front end of the front support rod to the front end of the rear tie rod.

3. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S4, the relative distance between the connection positions of the front support rod sling and the rear tie rod sling is adjusted by the operation of the rear hook, so that the sling can be connected to the front support rod and the rear tie rod respectively.

4. The method for suspending a tripod using slings according to claim 1, characterized in that: Before step S6, there is also step S60: the front hook and the rear hook work together to raise the tripod by a preset distance, which is not less than the length of the rear tie rod.

5. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S6, the front hook is pulled up, the rear hook remains stationary and the sling is taut. The rear tie rod is observed to be vertical, and the front hook stops rising.

6. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S7, as the front hook and rear hook move together to transport the tripod to the slewing platform, the rear tie rod remains vertical and the sling is taut.

7. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S8, the rear tie rod is first connected to one side of the slewing platform, then the hook runs, the position of the front support rod is adjusted, and the front support rod is connected to the other side of the slewing platform.

8. The method for suspending a tripod using slings according to claim 1, characterized in that: In step S1, the sling parameters include the length of the sling and the maximum preload of the sling. The length of the sling is determined based on the distance between the installation positions of the front support rod and the rear tie rod on the slewing platform, the distance between the sling installation position on the front support rod and the mounting hole on the front support rod, and the angle between the sling and the straight line containing the mounting hole on the front support rod and the mounting hole on the rear tie rod. The maximum preload of the sling is determined based on the weight of the rear tie rod, the length of the rear tie rod, and the center of gravity.

9. A method for suspending a tripod using slings according to claim 8, characterized in that: Step S5 also includes: the rear hook operates so that the tension of the sling is not greater than the maximum preload, thereby keeping the sling in a straight state.

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