Method for exchanging a sheave on a crane tripod

Abstract

The application provides a method for exchanging pulleys on a crane tripod, wherein a sliding suspension cable is arranged on a luffing steel wire rope, the two ends of the sliding suspension cable are arranged to cross the luffing steel wire rope and are respectively fixedly connected to the left and right sides of the top of the tripod, a binding belt is arranged to limit the movement of the sliding suspension cable on the luffing steel wire rope, a hand-operated hoist is arranged on the sliding suspension cable to lift the pulley to be exchanged, a traction rope is arranged to pull the hand-operated hoist, and then the pulley to be exchanged is moved through the sliding suspension cable, so that the pulleys on the left and right sides of the top of the tripod are exchanged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cranes, in particular to a method for interchanging pulleys on a crane tripod. BACKGROUND

[0002] With the gradual depletion of land resources, the development direction of resources has expanded to the ocean, and marine resources will dominate the world's resources in the future and become the focus of fierce competition among countries. To develop marine resources, advanced marine cranes are needed to transport goods and equipment. Cranes are widely used due to their small platform space occupation, compact structure, large lifting capacity, and long lifting radius. For example, Chinese patent number 201821574159.4, published on August 2, 2019, discloses a crane based on a flat special-shaped rotary platform, which includes a base, a rotary support, a rotary platform, a rotary drive device, a boom, and a tripod. The rotary platform uses two parallel rib plate groups; the structure of the front and rear center rib plate groups is beneficial to the dispersion of the stress of the rotary platform and can significantly improve the structural stability of the rotary platform. An axle hole is provided on the rotary platform, and a shaft sleeve is provided in the axle hole. The rotary drive device is arranged in the axle hole, which is convenient for maintenance and replacement. The tripod is connected by welding and flange connection, which is convenient for assembly and disassembly and facilitates transportation.

[0003] The crane in the above-mentioned document is provided with a tripod, and pulleys are installed on the tripod, which is convenient for the steel wire rope of the winch to pass through the pulleys of the tripod and then be connected to the boom. However, it is found that when the pulleys installed on the top of the tripod on the rotary platform are installed in reverse, the steel wire rope cannot be wound around the pulleys of the tripod until the pulleys are interchanged. Since the distance from the pulley to the ground is about one hundred meters, the use of a crane for operation is costly, and due to the high height, it is not convenient to replace the pulleys on both sides of the tripod, which ensures the safety of the operation. SUMMARY

[0004] The purpose of the present application is to provide a method for interchanging pulleys on a crane tripod, which can interchange the pulleys on the tripod using a luffing steel wire rope, is convenient to operate, and has low use cost.

[0005] To achieve the above-mentioned purpose, a method for interchanging pulleys on a crane tripod includes the following steps:

[0006] S2 determine the length of the sliding suspension cable, make the luffing steel wire rope in a straight state, mark the luffing steel wire rope directly above the pulley to be interchanged, and then change the luffing steel wire rope from the straight state to the relaxed state;

[0007] S3 sets the binding belt on both sides of the mark, connects one end of the sliding suspension cable to the lifting lug on the left side of the top of the tripod through the shackle, then passes the sliding suspension cable through the mark between the binding belts and fixes the sliding suspension cable on the luffing wire through the shackle at the mark, then connects the other end of the sliding suspension cable to the chain hoist and connects the chain hoist to the lifting lug on the right side of the top of the tripod through the shackle;

[0008] S4 sets the chain hoist on the sliding suspension cable and installs the traction rope on the chain hoist, then puts the sling through the rope groove of the pulley and makes the sling in a tightened state, connects the chain hoist on the sliding suspension cable to the sling through the shackle;

[0009] S5 moves the chain hoist on the sliding suspension cable to above the pulley to be exchanged respectively, then changes the luffing wire from a relaxed state to a taut state, then controls the chain hoist on the sliding suspension cable to tighten the pulley to be exchanged, so that the pulling force of the chain hoist is equal to the weight of the pulley to be exchanged;

[0010] S6 removes the pulley, hoists the pulley away from the pulley mounting plate through the chain hoist on the sliding suspension cable and the chain hoist arranged on the platform guardrail, fixes the pulley on the right side of the top of the tripod on the platform, then pulls the traction rope, moves the pulley on the left side of the top of the tripod to the pulley mounting plate on the right side of the top of the tripod for installation, after the installation of the pulley on the right side of the top of the tripod is completed, pulls the traction rope, moves the pulley on the platform to the pulley mounting plate on the left side of the top of the tripod for installation, and completes the exchange of the pulleys on the left and right sides of the top of the tripod.

[0011] The above setting, by crossing the sliding suspension cable over the wire rope and connecting both ends, then setting the electric hoist at the lower end of the sliding suspension cable to realize the left and right movement of the pulley, so as to realize the replacement of the pulley by using the wire rope, low cost, and by the length of the sliding suspension cable to determine the mark arranged on the luffing wire rope, so that the sliding suspension cable fixed on the luffing wire rope can be above the pulley to be exchanged after the luffing wire rope is taut, and then the pulley to be exchanged can be easily hoisted by the chain hoist arranged on the sliding suspension cable, the sliding suspension cable is fixed at the mark by setting the shackle, and the sliding suspension cable is limited in the setting direction of the wire rope by setting the binding belt, so as to prevent the sliding suspension cable from sliding along the length direction of the luffing wire rope on the luffing wire rope, thereby ensuring the safety of the operation.

[0012] Further, before step S2, it further includes step S1 of presetting the maximum deformation amount of the sliding suspension cable fixed on the luffing wire rope in the vertical direction , then calculating the maximum pre-tightening force of the sliding suspension cable according to the weight P of the pulley to be exchanged and the span L of the sliding suspension cable on the luffing wire rope ;

[0013] After the step S3 of "connecting the hand chain hoist to the lifting lug on the right side of the top of the tripod by unhooking", further comprising: making the pre-tightening force of the sliding suspension cable less than the maximum pre-tightening force S.

[0014] The above arrangement makes the pre-tightening force of the sliding suspension cable less than the maximum pre-tightening force S after the two ends of the sliding suspension cable are connected, so that the sliding suspension cable can be pulled up and moved upward after the pulley is hung on the lower end of the sliding suspension cable, ensuring the reliability of pulling.

[0015] Further, the sliding suspension cable comprises a left sliding suspension cable and a right sliding suspension cable, the left sliding suspension cable is arranged above the pulley on the left side of the top of the tripod, passes through the marked position to cross the luffing wire rope, and is fixed on the lifting lugs on the left and right sides of the top of the tripod; the right sliding suspension cable is arranged above the pulley on the right side of the top of the tripod, passes through the marked position to cross the luffing wire rope, and is fixed on the lifting lugs on the left and right sides of the top of the tripod.

[0016] The above arrangement facilitates the left pulley on the top of the tripod after being disassembled to slide to the right side of the top of the tripod through the left sliding suspension cable, and facilitates the right pulley on the top of the tripod after being disassembled to slide to the left side of the top of the tripod through the right sliding suspension cable.

[0017] Further, the step S1 of calculating the pre-tightening force The calculation formula is as follows:

[0018]

[0019] Wherein P is the weight of the pulley to be exchanged, g is the acceleration of gravity, L is the span of the sliding suspension cable on the luffing wire rope, is the angle between the sliding suspension cable and the horizontal when the sliding suspension cable is not hung with the pulley, is the maximum deformation in the vertical direction when the sliding suspension cable is hung with the pulley, and then the pre-tightening force of the left sliding suspension cable and the right sliding suspension cable is calculated respectively.

[0020] The above arrangement facilitates the calculation of the pre-tightening force of the sliding suspension cable.

[0021] Further, the length of the sliding suspension cable in the step S2 is the sum of the span l of the sliding suspension cable on the luffing wire rope, the distance from the luffing wire rope to the lifting lug on the left side of the top of the tripod, and the distance from the luffing wire rope to the lifting lug on the right side of the top of the tripod.

[0022] The above arrangement facilitates the calculation of the length of the sliding suspension cable in advance, so that the sliding suspension cable can be installed and fixed on the left and right sides of the top of the tripod after crossing the luffing wire rope.

[0023] Further, the step S4 further comprises:

[0024] ​The disengaging buckle is arranged at the lower end of the hand chain block, the sling is sleeved on the pulley and connected with the disengaging buckle, and then the disengaging buckle is driven by the hand chain block to move upward, so as to drive the sling to change from the relaxed state to the tightened state.

[0025] The above arrangement can tightly lock the to-be-interchanged pulley by the sling, so as to facilitate the disassembly and movement of the pulley.

[0026] Further, the step S5 further comprises:

[0027] The hand chain block on the left sliding suspension cable is moved above the pulley on the left side of the top of the tripod, the hand chain block on the right sliding suspension cable is moved above the pulley on the right side of the top of the tripod, after the amplitude wire rope becomes in the taut state, the pre-tightening force of the left sliding suspension cable and the right sliding suspension cable is adjusted to the pre-tightening force calculated in the step S1 by the hand chain block connected with the left sliding suspension cable and the hand chain block connected with the right sliding suspension cable respectively, so that the left sliding suspension cable and the right sliding suspension cable are in the taut state.

[0028] The above arrangement can move the pulley in the preset deformation amount, prevent the deformation amount of the sliding suspension cable from being too large, and thus facilitate the worker to move the hand chain block by pulling the rope.

[0029] Further, the step S6 further comprises:

[0030] After the pulley on the right side of the top of the tripod is removed, the pulley on the right side of the top of the tripod is driven by the hand chain block on the right sliding suspension cable to move upward by 800 mm, and then the pulley on the right side of the top of the tripod is driven by the hand chain block arranged on the platform guardrail on the right side of the top of the tripod to move by 550 mm in the direction of the platform, so that the pulley on the right side of the top of the tripod is separated from the pulley mounting plate on the right side of the top of the tripod and is fixed on the platform.

[0031] The hand puller on the left sliding suspension cable drives the pulley on the left side of the tripod top to move up 800mm, then the hand puller arranged on the platform guardrail on the left side of the tripod top is used to pull the knot arranged on the sling, so that the pulley on the left side of the tripod top moves 550mm to the direction of the platform, the pulley on the left side of the tripod top is separated from the pulley mounting plate on the left side of the tripod top, the traction rope is pulled, the pulley on the left side of the tripod top is driven to move to the right for a distance, then the hand puller on the platform guardrail on the left side of the tripod top is loosened, so that the pulley on the left side of the tripod top is only subjected to the vertical pulling force of the hand puller on the left sliding suspension cable, then the traction rope is pulled, when the pulley on the left side of the tripod top moves to the front of the pulley mounting plate on the right side of the tripod top, the other hand puller arranged on the platform guardrail on the right side of the tripod top is used to pull the pulley on the left side of the tripod top to move to the direction of the platform for a distance, then the traction rope is pulled, so that the pulley on the left side of the tripod top continues to move to the upper side of the pulley mounting plate on the right side of the tripod top, then the other hand puller on the platform guardrail on the right side of the tripod top is loosened, so that the pulley on the left side of the tripod top enters the pulley mounting plate on the right side of the tripod top, finally the pulley moved from the left side to the right side of the tripod top is installed.

[0032] After the pulley on the left side of the tripod top is moved to the pulley mounting plate on the right side of the tripod top and installed, the traction rope is pulled, so that the hand puller on the right sliding suspension cable drives the pulley on the right side of the tripod top to move left for a distance and then stop, the hand puller on the platform guardrail on the right side of the tripod top is loosened, so that the pulley on the right side of the tripod top is only subjected to the vertical pulling force of the hand puller on the right sliding suspension cable, then the traction rope is pulled, when the pulley on the right side of the tripod top moves to the front of the pulley mounting plate on the left side of the tripod top, the other hand puller arranged on the platform guardrail on the left side of the tripod top is used to pull the pulley on the right side of the tripod top to move to the direction of the platform for a distance, then the traction rope is pulled, so that the pulley on the right side of the tripod top continues to move to the upper side of the pulley mounting plate on the left side of the tripod top, then the other hand puller on the platform guardrail on the left side of the tripod top is loosened, so that the pulley on the right side of the tripod top enters the pulley mounting plate on the left side of the tripod top, finally the pulley moved from the right side to the left side of the tripod top is installed.

[0033] The above arrangement can avoid the collision of the pulleys on the left and right sides of the tripod top during movement and cannot be interchanged. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a schematic diagram of the three-dimensional structure of the application.

[0035] Figure 2 It is a schematic diagram of the pulley separating from the pulley mounting plate in the application.

[0036] Figure 3 This is a schematic diagram of the connection between the sling and the hand-operated hoist in this invention.

[0037] Figure 4 This is a left-side view of the present invention.

[0038] Figure 5 This is a right-side view of the present invention.

[0039] Figure 6 This is a schematic diagram showing the connection between the variable amplitude wire rope, the sliding suspension cable, and the pulley frame in this invention. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0041] like Figures 1 to 5 As shown, a method for interchangeable pulleys on a crane tripod includes the following specific steps:

[0042] S1 is the maximum vertical deformation of the sliding suspension cable fixed to the luffing wire rope 1. Then, based on the weight P of the pulley 2 to be interchanged and the span L of the sliding suspension cable on the luffing wire rope 1, the maximum preload of the sliding suspension cable is calculated. Maximum preload The formula is as follows:

[0043] ,

[0044] Where P is the weight of the pulley 2 to be replaced, g is the acceleration due to gravity, and L is the span of the sliding suspension cable on the luffing wire rope 1. The angle between the sliding suspension cable and the horizontal when pulley 2 is not attached to the sliding suspension cable. The maximum vertical deformation of the sliding suspension cable when the pulley is attached to it is the maximum deformation in the vertical direction. In this embodiment, the sliding suspension cable includes a left sliding suspension cable 3 and a right sliding suspension cable 4. Then, the preload of the left sliding suspension cable 3 and the right sliding suspension cable 4 are calculated respectively.

[0045] S2 determines the length of the sliding suspension cable. In this embodiment, the length of the sliding suspension cable is the sum of the span L of the sliding suspension cable on the luffing wire rope 1, the distance from the luffing wire rope 1 to the left sling 5 at the top of the tripod, and the distance from the luffing wire rope 1 to the right sling 6 at the top of the tripod. The luffing wire rope 1 is kept taut, and a mark is made on the luffing wire rope 1 directly above the pulley 2 to be interchanged. Then, the luffing wire rope 1 is changed from a taut state to a slack state. In this embodiment, the tension state of the luffing wire rope 1 is controlled by the luffing controller.

[0046] S3 sets the binding belt 7 on both sides of the mark, connects one end of the left sliding suspension cable 3 with the left hanging ear 5 on the top of the tripod through the shackle 8, then passes the left sliding suspension cable 3 through the mark between the binding belts 7 and fixes the left sliding suspension cable 3 on the luffing wire rope 1 at the mark through the shackle 8, then connects the other end of the left sliding suspension cable 3 with the hand-operated hoist 9 and connects the hand-operated hoist 9 with the right hanging ear 6 on the top of the tripod through the shackle 8, and makes the pre-tightening force of the sliding suspension cable not more than the maximum pre-tightening force, so that the left sliding suspension cable 3 is arranged above the pulley 2 on the left side of the top of the tripod;

[0047] Connects one end of the right sliding suspension cable 4 with the left hanging ear 5 on the top of the tripod through the shackle 8, then passes the right sliding suspension cable 4 through the mark between the binding belts 7 and fixes the right sliding suspension cable 4 on the luffing wire rope 1 at the mark through the shackle 8, then connects the other end of the right sliding suspension cable 4 with the hand-operated hoist 9 and connects the hand-operated hoist 9 with the right hanging ear 6 on the top of the tripod through the shackle 8, so that the right sliding suspension cable 4 is arranged above the pulley 2 on the right side of the top of the tripod.

[0048] S4 sets the hand-operated hoist 9 on the left sliding suspension cable 3 and the right sliding suspension cable 4 respectively, sets the shackle 8 on the lower end of the hand-operated hoist 9, then installs the traction rope 10 on the hand-operated hoist 9, then puts the sling 71 around the pulley 2 along the rope groove of the pulley 2, connects the sling 71 with the shackle 8 after the sling 71 is put around the pulley 2, drives the shackle 8 to move upward through the hand-operated hoist 9, and then drives the sling 71 to change from the relaxed state to the tightened state.

[0049] S5 moves the hand-operated hoist 9 on the left sliding suspension cable 3 above the pulley 2 on the left side of the top of the tripod, moves the hand-operated hoist 9 on the right sliding suspension cable 4 above the pulley 2 on the right side of the top of the tripod, then changes the luffing wire rope 1 from the relaxed state to the taut state, after the luffing wire rope 1 changes to the taut state, adjusts the pre-tightening force of the left sliding suspension cable 3 and the right sliding suspension cable 4 to the pre-tightening force calculated in step S1 through the hand-operated hoist 9 connected with the left sliding suspension cable 3 and the hand-operated hoist 9 connected with the right sliding suspension cable 4 respectively, so that the left sliding suspension cable 3 and the right sliding suspension cable 4 are in the taut state, then controls the hand-operated hoist 9 on the left sliding suspension cable 3 and the right sliding suspension cable 4 to tighten the pulley 2 to be interchanged respectively, so that the pulling force of the hand-operated hoist 9 is equal to the gravity of the pulley 2 to be interchanged;

[0050] S6 removes the stop plate and the pin shaft of the pulleys 2 on the left and right sides of the top of the tripod respectively, after removing the pulley 2 on the right side of the top of the tripod, drives the pulley 2 on the right side of the top of the tripod to move upward by 800mm through the hand-operated hoist 9 on the right sliding suspension cable 4, then drives the pulley 2 on the right side of the top of the tripod to move 550mm in the direction of the platform through the hand-operated hoist set on the platform guardrail 11 on the right side of the top of the tripod, so that the pulley 2 on the right side of the top of the tripod is separated from the pulley mounting plate on the right side of the top of the tripod and is fixed on the platform.

[0051] Pull the hand-operated hoist 9 on the left sliding suspension cable 3 to move the pulley 2 on the left side of the tripod top up by 800mm, then pull the knot on the sling 71 by the hand-operated hoist 9 arranged on the platform guardrail 11 on the left side of the tripod top to move the pulley 2 on the left side of the tripod top 550mm towards the platform, so that the pulley 2 on the left side of the tripod top is separated from the pulley mounting plate on the left side of the tripod top, and the traction rope 10 is pulled to move the pulley 2 on the left side of the tripod top by a certain distance to the right and then stop, the hand-operated hoist 9 on the platform guardrail on the left side of the tripod top is released, so that the pulley 2 on the left side of the tripod top is only subjected to the vertical pulling force of the hand-operated hoist 9 on the left sliding suspension cable 3, then the traction rope 10 is pulled to move the pulley 2 on the left side of the tripod top to the front of the pulley mounting plate on the right side of the tripod top, then another hand-operated hoist arranged on the platform guardrail on the right side of the tripod top is used to pull the pulley 2 on the left side of the tripod top to move a certain distance towards the platform, then the traction rope 10 is pulled to continue moving the pulley 2 on the left side of the tripod top to the upper side of the pulley mounting plate on the right side of the tripod top, then another hand-operated hoist arranged on the platform guardrail on the right side of the tripod top is released, so that the pulley 2 on the left side of the tripod top enters the pulley mounting plate on the right side of the tripod top, and finally the pulley 2 moved from the left side to the right side of the tripod top is installed;

[0052] After the pulley 2 on the left side of the tripod top is moved to the pulley mounting plate on the right side of the tripod top and installed, the traction rope 10 is pulled to move the pulley 2 on the right side of the tripod top by a certain distance to the left by the hand-operated hoist 9 on the right sliding suspension cable 4 and then stop, the hand-operated hoist on the platform guardrail on the right side of the tripod top is released, so that the pulley 2 on the right side of the tripod top is only subjected to the vertical pulling force of the hand-operated hoist 9 on the right sliding suspension cable 4, then the traction rope 10 is pulled to move the pulley 2 on the right side of the tripod top to the front of the pulley mounting plate on the left side of the tripod top, then another hand-operated hoist arranged on the platform guardrail on the left side of the tripod top is used to pull the pulley 2 on the right side of the tripod top to move a certain distance towards the platform, then the traction rope 10 is pulled to continue moving the pulley 2 on the right side of the tripod top to the upper side of the pulley mounting plate on the left side of the tripod top, then another hand-operated hoist arranged on the platform guardrail on the left side of the tripod top is released, so that the pulley 2 on the right side of the tripod top enters the pulley mounting plate on the left side of the tripod top, and finally the pulley moved from the right side to the left side of the tripod top is installed, thereby completing the exchange of the pulleys on the left and right sides of the tripod top.

[0053] The working principle of the present application is as follows: the sliding suspension cable is arranged on the variable-amplitude steel wire rope, the two ends of the sliding suspension cable are fixedly connected with the left and right sides of the top of the tripod respectively after crossing the variable-amplitude steel wire rope, the movement of the sliding suspension cable on the variable-amplitude steel wire rope is limited by arranging the binding belt, the hand-operated hoist arranged on the sliding suspension cable is used to hoist the pulley to be exchanged for dismounting, the hand-operated hoist is pulled by the traction rope, and then the pulley to be exchanged is moved through the sliding suspension cable, so that the pulley exchange on the left and right sides of the top of the tripod is realized.

Claims

1. A method for interchangeable pulleys on a crane tripod, characterized in that: Includes the following steps: S2 determines the length of the sliding suspension cable, keeps the luffing wire rope taut, marks the luffing wire rope directly above the pulley to be swapped, and then lets the luffing wire rope change from taut to slack. S3 sets straps on both sides of the marked point, connects one end of the sliding suspension cable to the lifting lug on the top left of the tripod through a shackle, then passes the sliding suspension cable through the marked point between the straps and fixes the sliding suspension cable to the luffing wire rope through the shackle at the marked point. Then connects the other end of the sliding suspension cable to the hand chain hoist and connects the hand chain hoist to the lifting lug on the top right of the tripod through a shackle. S4. Install a hand chain hoist on the sliding suspension cable and install a traction rope on the hand chain hoist. Then, loop the sling along the rope groove of the pulley and tighten the sling. Connect the hand chain hoist on the sliding suspension cable to the sling through a shackle. S5 moves the hand chain hoists on the sliding suspension cable to above the pulleys to be replaced, then changes the luffing wire rope from a slack state to a taut state, and then controls the hand chain hoists on the sliding suspension cable to tighten the pulleys to be replaced, so that the pulling force of the hand chain hoists is equal to the weight of the pulleys to be replaced. S6 Remove the pulley, and use the hand-operated hoists on the sliding suspension cable and the platform railing to lift the pulley off the pulley mounting plate and fix the pulley on the top right side of the tripod to the platform. Then pull the traction rope to move the pulley on the top left side of the tripod to the pulley mounting plate on the top right side of the tripod for installation. After the pulley on the top right side of the tripod is installed, pull the traction rope to move the pulley on the platform to the pulley mounting plate on the top left side of the tripod for installation, thus completing the interchange of the left and right pulleys on the top of the tripod.

2. The method for interchangeable pulleys on a crane tripod according to claim 1, characterized in that: Before step S2, step S1 includes setting the maximum vertical deformation of the sliding suspension cable fixed on the luffing wire rope. Then, based on the weight P of the pulleys to be interchanged and the span L of the sliding suspension cable on the luffing wire rope, the maximum preload of the sliding suspension cable is calculated. ; In step S3, after "connecting the hand chain hoist to the lifting lug on the top right side of the tripod via the shackle", the following is also included: making the preload of the sliding suspension cable less than the maximum preload S.

3. The method for interchangeable pulleys on a crane tripod according to claim 1, characterized in that: The sliding suspension cable includes a left sliding suspension cable and a right sliding suspension cable. The left sliding suspension cable is set above the left pulley at the top of the tripod, and passes through the marked point, crosses the luffing wire rope, and is fixed to the lugs on the left and right sides of the top of the tripod. The right sliding suspension cable is set above the right pulley at the top of the tripod, and passes through the marked point, crosses the luffing wire rope, and is fixed to the lugs on the left and right sides of the top of the tripod.

4. The method for interchangeable pulleys on a crane tripod according to claim 2, characterized in that: In step S1, the preload is calculated. The calculation formula is as follows: ， Where P is the weight of the pulleys to be interchanged, g is the acceleration due to gravity, and L is the span of the sliding suspension cable on the luffing wire rope. This refers to the angle between the sliding suspension cable and the horizontal when no pulley is attached to it. The maximum vertical deformation of the sliding suspension cable when the pulley is attached is given. Then, the preload of the left and right sliding suspension cables is calculated separately.

5. The method for interchangeable pulleys on a crane tripod according to claim 1, characterized in that: In step S2, the length of the sliding suspension cable is the sum of the span l of the sliding suspension cable on the luffing wire rope, the distance from the luffing wire rope to the left lug at the top of the tripod, and the distance from the luffing wire rope to the right lug at the top of the tripod.

6. The method for interchangeable pulleys on a crane tripod according to claim 1, characterized in that: Step S4 also includes: A shackle is installed at the lower end of the hand chain hoist. The sling is connected to the shackle after it is looped around the pulley. Then, the shackle is moved upward by the hand chain hoist, which in turn causes the sling to change from a slack state to a tightened state.

7. A method for interchangeable pulleys on a crane tripod according to claim 2, characterized in that: Step S5 also includes: Move the hand-operated hoist on the left sliding suspension cable to the pulley on the top left side of the tripod, and move the hand-operated hoist on the right sliding suspension cable to the pulley on the top right side of the tripod. After the luffing wire rope becomes taut, adjust the preload of the left and right sliding suspension cables to the preload calculated in step S1 using the hand-operated hoists connected to the left and right sliding suspension cables respectively, so that the left and right sliding suspension cables are in a taut state.

8. The method for interchangeable pulleys on a crane tripod according to claim 1, characterized in that: Step S6 further includes: After removing the pulley on the top right side of the tripod, use the chain hoist on the right sliding suspension cable to move the pulley on the top right side of the tripod upward by 800mm. Then, use the chain hoist on the platform railing on the top right side of the tripod to pull the pulley on the top right side of the tripod 550mm towards the platform, so that the pulley on the top right side of the tripod is detached from the pulley mounting plate on the top right side of the tripod and fixed on the platform. The hand-operated hoist on the left sliding suspension cable moves the pulley on the top left side of the tripod upwards by 800mm. Then, the hand-operated hoist on the platform railing on the top left side of the tripod pulley pulls the knot on the sling, causing the pulley to move 550mm towards the platform. This disengages the pulley from its mounting plate. Pulling the traction rope then moves the hand-operated hoist on the left sliding suspension cable to the right, moving it a short distance before stopping. The hand-operated hoist on the platform railing on the top left side of the tripod is then released, leaving the pulley on the top left side of the tripod only supported by the hand-operated hoist on the left sliding suspension cable in the vertical direction. Pull the traction rope to move the pulley on the left side of the top of the tripod to the right. When the pulley is in front of the pulley mounting plate on the right side of the top of the tripod, pull the pulley on the left side of the top of the tripod towards the platform by another hand chain hoist set on the right side platform railing. Then pull the traction rope to move the pulley on the left side of the top of the tripod to the right and above the pulley mounting plate on the right side of the top of the tripod. Then release the other hand chain hoist on the right side platform railing to let the pulley on the left side of the top of the tripod enter the pulley mounting plate on the right side of the top of the tripod. Finally, install the pulley that has moved from the left side to the right side of the top of the tripod. After moving the pulley on the top left of the tripod to the installation plate of the pulley on the top right of the tripod, pull the traction rope to move the pulley on the top right of the tripod to the left a certain distance using the hand chain hoist on the right sliding suspension cable, then release the hand chain hoist on the platform railing on the top right of the tripod, so that the pulley on the top right of the tripod is only subjected to the vertical tension of the hand chain hoist on the right sliding suspension cable. Then pull the traction rope to move the pulley on the top right of the tripod to the left until it is in front of the installation plate of the pulley on the top left of the tripod. Then, use another hand chain hoist on the platform railing on the top left of the tripod to move the pulley on the top right of the tripod towards the platform a certain distance. Then pull the traction rope to move the pulley on the top right of the tripod further to the left until it is above the installation plate of the pulley on the top left of the tripod. Then release the other hand chain hoist on the platform railing on the top left of the tripod so that the pulley on the top right of the tripod enters the installation plate of the pulley on the top left of the tripod. Finally, install the pulley that has moved from the top right to the left of the tripod.

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