CN114920132A - Balanced hoisting device and method applied to field installation of shield tunneling machine - Google Patents

Abstract

The invention relates to a balance hoisting device applied to the on-site installation of a shield machine, which is applied in the technical field of balance hoisting tooling, and solves the technical problem of difficult hoisting due to a small wellhead. The device comprises a balance beam and a main lifting lug located on the balance beam. And the stack below the balance beam is provided with two groups of mobile lifting lugs, a number of hoisting hoists are suspended on the mobile lifting lugs, the lower surface of the balance beam is fixed with a connecting seat, and the mobile lifting lugs are slidably connected to the In the connection seat, the balance beam is provided with a screw rod for adjusting the movable lifting lug, a stopper is welded on the balance beam, the screw rod passes through the stopper block and is threadedly connected with two nuts. The invention has the effect of efficiently and safely assembling the shield machine trolley.

Description

Balance hoisting device and method applied to on-site installation of shield machine

technical field

The invention relates to the technical field of shield machine hoisting, and more particularly, to a balanced hoisting device and method applied to the on-site installation of shield machines.

Background technique

The shield machine is called the underground steel dragon, and it is a kind of core construction machinery in tunnel engineering. The shield machine has different specifications according to the excavation diameter. The diameter of the small shield is 6 meters, and the diameter of the large shield is between 14 meters and 17 meters. The assembly of the shield machine is largely dependent on crane assembly, and the difficulty of hoisting is greatly affected by the working conditions of the construction site.

As shown in Figure 13, the end face structure diagram of the hoisting shaft on the construction site, the supporting components behind the shield machine are placed on the trolley, and the trolley is used to synchronize with the host. Taking a shield machine with an excavation diameter of 14 meters as an example, the width of the trolley is 11 meters and the width of the wellhead is 7 meters. 73 and 74 on the upper platform. It is now necessary to assemble the left part 71, the right part 72, the lower platform 73 and the upper platform 74 as in the well.

The assembly process is to install the lower platform first, then install the left outrigger and right outrigger, and finally install the upper platform. However, due to the small width of the wellhead, the outrigger and the right outrigger cannot be hoisted to the designated position. Therefore, it is necessary to design a balanced hoisting device and an assembly method to solve the above problems.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the prior art, one of the objectives of the present invention is to provide a balance hoisting device applied to the on-site installation of shield tunneling machines. Lift the workpiece to the designated position under certain circumstances to improve the efficiency of assembly.

The above-mentioned technical purpose of the present invention is achieved through the following technical solutions: a balance hoisting device applied to the on-site installation of a shield machine, comprising a balance beam, a main lifting lug located on the balance beam, and a stacking device located below the balance beam There are two sets of mobile lifting lugs, a number of hoisting hoists are suspended on the mobile lifting lugs, a connecting seat is fixed on the lower surface of the balance beam, the mobile lifting lugs are slidably connected in the connecting seat, and the balance beam is slidably connected to the connecting seat. A screw rod is provided for adjusting the moving lifting lug, a stopper is welded on the balance beam, the screw rod passes through the stopper block and is threadedly connected with two nuts.

The effect achieved by the above settings: through the setting of the balance beam, the lifting point of the workpiece and the lifting point of the hoist are not on the same vertical line, thereby achieving the purpose of changing the lifting point of the workpiece, so that the workpiece can be removed even when the wellhead is small. Lift to the designated position. The mobile lifting lugs are used to adjust the opening size of the left and right components, and further adapt to different sizes of shield machines and then assembled together.

It is further provided that a limit plate is slidably arranged in the connecting seat, the movable lifting lug includes a sliding plate and a lifting ring plate, and a limit groove and a protrusion that are clamped to each other are arranged between the sliding plate and the limit plate, and the The connecting seat is threadedly connected with a limit bolt for abutting against the limit plate; when the position of the movable lifting lug is adjusted, it is locked by the limit plate.

The effect achieved by the above settings: due to the difference in the weight of the workpiece, when the workpiece and the balance beam are separated from the ground, the inclination angle of the balance beam is unknown. Set to prevent the skateboard from sliding.

Further setting: it also includes an adjusting hoist, the adjusting hoist is connected to the two hoisting parts.

The effect achieved by the above settings: the adjustment hoist prevents huge shaking when the left and right parts are lifted off the ground, thereby avoiding potential safety hazards and damage to the workpiece; at the same time, with the lifting hoist, the posture of the workpiece can be quickly adjusted to improve the installation efficiency.

Further setting: the balance beam is provided with a drive device for driving the movement of the main lifting lug, the drive device includes a base fixed on the balance beam, a ring gear and a worm that are rotatably arranged on the base, and the worm and the ring gear are engaged. The ring gear is internally meshed with a transmission gear, the base is slidably provided with a rack, the rack is meshed with the transmission gear, the rack is fixedly connected with the main lifting lug, and one end of the worm There is a motor for driving the worm to rotate;

After the motor drives the worm to rotate, it drives the ring gear to rotate, the ring gear drives the driven gear to rotate, and the driven gear drives the rack to move.

The effect achieved by the above settings: when the balance beam is inclined, the motor can be remotely controlled on the ground or underground, and then the position of the main lifting lug can be automatically controlled to ensure that the balance beam is in a horizontal state, ensure the opening size of the left and right parts, and can be connected with the middle part. .

Further setting: the base includes a bottom plate fixed on the balance beam, a connecting plate connected on the bottom plate by bolts, and a cover fixed on the connecting plate by bolts, a positioning ring protruding from the lower surface of the ring gear, the The positioning ring is inserted into the connecting plate and the bottom plate, the inner side, outer side and bottom surface of the positioning ring and the upper surface of the ring gear are all provided with a number of steel balls, and the steel balls are rolled on the base.

The effect achieved by the above settings: the ring gear itself needs to be rotated, and the inner and outer rings of the ring gear have gear teeth. At this time, the ring gear loses the positioning device and the components that are difficult to install the bearing. At this time, the positioning ring and the steel ball are used to make the ring gear suspended. At the same time, it is restrained to ensure that the entire drive unit runs more smoothly.

The second purpose of the present invention is to provide a method for on-site installation of a shield machine, the advantage of which is that the lifting point of the workpiece is indirectly changed through the balance beam, so that the workpiece can be lifted to a designated position when the wellhead is small, and the assembly efficiency is improved .

The above-mentioned technical purpose of the present invention is achieved through the following technical solutions: a method for on-site installation of a shield machine, comprising the following steps:

10. Lift the left part and the right part of the shield machine trolley to go down the well respectively;

20. Hoist the middle part of the trolley of the shield machine down the well;

30. Align the short side of the balance beam with the short side of the wellhead and go down the well, then rotate it 90 degrees, and then connect the hooks of the left and right hoists to the left and right parts respectively;

40. Hang the two ends of the adjusting hoist on the left and right parts respectively;

50. Manually pull the hoist at the same time. By adjusting the hoist and the adjusting hoist, the left part and the right part are lifted off the ground at the same time and docked with the middle part, and finally fixed with bolts

Further settings: between steps 40 and 50, the following steps are also included:

41. Adjust the distance between the mobile lifting lugs on the left and right sides, so that after the left part and the right part are lifted off the ground, the distance in the middle is larger than the structure of the middle part;

42. After the hoist is hooked, carry out trial lifting, and move the lifting lugs by fine-tuning to make the balance beam in a horizontal state.

Compared with the prior art, the present invention has the following beneficial effects:

1. For the condition that the width of the wellhead is less than the width of the trolley, put the components into the well in advance, and then place the balance beam so that the lifting point can bypass the interference position of the wellhead and extend to both sides of the well, and further use the lifting hoist to lift the shaft. Parts are hoisted. During this process, the balance beam is prevented from rolling over, and the two sides are hoisted symmetrically at the same time, and finally the lifting point of the crane and the lifting point of the workpiece are staggered, so that the assembly can be carried out smoothly;

2. Multiple lifting hoists cooperate with adjusting hoists and movable mobile lifting lugs, which can easily adjust the posture of the components, making the process of bolting smoother and reducing construction difficulty and safety risks.

3. It is suitable for the assembly of all shield machine trolley parts, with strong versatility.

Description of drawings

Fig. 1 is the structural representation of the present embodiment 1 and the workpiece as a whole;

Fig. 2 is the three-dimensional structural representation of the present embodiment 1;

Fig. 3 is the structural schematic diagram of the embodiment 1 embodying the movable lifting lug;

Fig. 4 is the overall structural representation of the present embodiment 2;

FIG. 5 is a schematic structural diagram of the embodiment of the driving device of the second embodiment;

Fig. 6 is A-A sectional view in Fig. 4;

7 is a schematic structural diagram of step 1 of the present embodiment 3;

8 is a schematic structural diagram of step 2 of the present embodiment 3;

Fig. 9 is the structural representation of step 3, 4, 5 of the present embodiment 3;

10 is a schematic structural diagram of steps six and seven of the present embodiment 3;

Fig. 11 is the structural representation of the present embodiment 4;

Fig. 12 is the structural representation of the present embodiment 5;

Figure 13 is a schematic structural diagram of the assembly of the underground shield machine trolley;

Fig. 13b is a schematic diagram of an interference structure assembled on a conventional shield machine trolley.

In the picture: 1. Balance beam; 2. Main lifting lug; 3. Mobile lifting lug; 31. Lifting ring plate; 32. Slide plate; 33. Connecting seat; 34. Limit plate; 35. Screw rod; 36. Stopper; 4 , lifting hoist; 5, adjusting hoist; 61, base; 611, bottom plate; 612, connecting plate; 613, cover; 614, steel ball; 615, pressure ring; 616, limit block; 62, ring gear; 621, Locating ring; 63, worm; 64, driven gear; 65, rack; 66, limit wheel; 67, motor; 71, left part; 72, right part; 73, lower platform; 74, upper platform.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

Example 1:

Referring to Figures 1-3, a balance hoisting device applied to the on-site installation of a shield machine includes a balance beam 1, four main lifting lugs 2 located on the upper surface of the balance beam 1 and a mobile lifting lug 3 located on the lower surface of the balance beam 1 , the mobile lifting lugs 3 are divided into two groups, left and right, and a 10-ton or 20-ton manual lifting hoist 4 is hung on the mobile lugs 3. The opening of the main lifting lug 2 is 6 meters. The width of the balance beam 1 is 6 meters and the length is between 11-13 meters. Four hoists 4 are arranged on both sides of the balance beam 1 to adjust the posture of the shield machine components.

1-3, the lower surface of the balance beam 1 is welded with a connecting seat 33, the connecting seat 33 is in one-to-one correspondence with the movable lifting lug 3, the movable lifting lug 3 is slidably arranged in the connecting seat 33, and the movable lifting lug 3 includes two The lifting ring plate 31 and a sliding plate 32, the two lifting ring plates 31 are welded with the sliding plate 32, and the two lifting ring plates 31 are separated by 0.8-1.2 meters. The sliding plate 32 slides to set the connecting seat 33 , and the hanging ring plate 31 protrudes downwardly from the connecting seat 33 . A stopper 36 is welded on the balance beam 1, and a screw rod 35 is welded on the lifting ring plate 31. The screw rod 35 passes through the stopper 36 and is threadedly connected with two nuts. The nuts are located on both sides of the stopper 36, and the screw is realized by two nuts. The movement of 35 further drives the movement of the mobile lifting lug 3 .

Referring to Figure 1-3, during the design process of the shield machine, although the frame structure is designed symmetrically, due to the difference in the components and the error in the position of the lifting lugs, the parts on both sides will be different in weight, and then After the balance beam 1 and the workpiece are lifted off the ground at the same time, the balance beam 1 is inclined, which will generate a large horizontal component force and increase the safety risk; at the same time, the opening size of the middle of the workpiece will become smaller, and it will interfere with the intermediate components in severe cases. Increase the difficulty of construction. Therefore, the movable lifting lugs 3 are set to be movable to adjust the size between the left and right components, improve the versatility of application, and also have a certain leveling ability.

Referring to FIGS. 1-3 , a groove is set in the middle position of the connecting seat 33 , a limit plate 34 is arranged in the groove, and a bump and a limit groove are arranged between the sliding plate 32 and the limit plate 34 . This embodiment The middle convex block is integrally provided with the limiting plate 34, and the cross section of the convex block can be semicircular, rectangular, triangular, toothed and so on. The limit plate 34 can slide along the width direction of the slide plate 32, and three limit bolts are threadedly connected on the connecting seat 33. When the position of the moving lifting lug 3 needs to be adjusted, loosen the limit bolts, turn the nut, and then pass the screw 35. The movable lifting lug 3 is driven to move in the connecting seat 33 .

Referring to Fig. 1-3, since the tilt angle of the balance beam 1 is unknown before the lifting, once the tilt angle exceeds the safety factor of the screw 35, there will be a risk of objects falling from high altitudes. The above settings play a role in preventing the sliding plate 32 from sliding and improving safety. coefficient.

Referring to Figures 1-3, an adjusting hoist 5 is set between the left part and the right part. At the beginning, use a ruler to ensure that the distance between the moving lifting lugs 3 is greater than the width of the middle part, and then adjust the hoist 5 to make the parts close inward, so that through Adjust the hoist 5 to control the distance between the components on the left and right sides, so as not to interfere with the middle component, nor to cause the bolt length to be insufficient due to excessive clearance.

Embodiment 2, referring to FIGS. 4-6 , on the basis of Embodiment 1, the main lifting lug 2 is set to be adjustable, which further solves the problems of the inclination of the balance beam 1 and the inconsistency of the weights of the components on both sides. The balance beam 1 is provided with a drive device for driving the main lifting lug 2 to move. The drive device includes a base 61 fixed on the balance beam 1, a ring gear 62 and a worm 63 that are rotatably arranged on the base 61, and the worm 63 and the ring gear 62 are meshed The ring gear 62 is internally meshed with a transmission gear, the base 61 is slidably provided with a rack 65, the rack 65 is meshed with the transmission gear, the rack 65 is fixedly connected with the main lifting lug 2, and one end of the worm 63 is provided with a The motor 67 that drives the worm 63 to rotate;

4-6, when the motor 67 drives the worm 63 to rotate, the worm 63 drives the ring gear 62 to rotate, the ring gear 62 rotates and drives the driven gear 64 to rotate, and the driven gear 64 drives the rack 65 to move, thereby driving the main lifting lug 2 Turn. The above arrangement realizes automatic adjustment of the position of the balance beam 1 through the motor 67, instead of manual adjustment, which is more convenient and efficient.

4-6, the gear ratio of the worm 63 to the ring gear 62 is greater than 40:1, and the gear ratio of the ring gear 62 to the driven gear 64 is less than 2:1, so the gear ratio converted into the turbine and the rack 65 will be greater than 20:1 , the motor 67 adopts a torque of 100N*M, and finally the push-pull force of the rack 65 is at least 4 tons, and the total push-pull force of the four racks 65 is 16 tons. According to the friction coefficient of 0.1, when the balance beam 1 hangs below the components within 150 tons It can be adjusted at any time, and the performance of the drive device is suitable for all the parts of the large shield trolley known at present.

4-6, the base 61 includes a base plate 611 fixed on the balance beam 1, a connecting plate 612 detachably provided on the base plate 611 by bolts, and a cover 613 fixed on the connecting plate 612, the outer side of the ring gear 62 is Turbine tooth structure, the inner ring is the gear tooth structure of the gear, the worm gear 63 is used to generate a large transmission ratio, and then a large output force is obtained, and the worm 63 is selected to drive the ring gear 62, and the lead angle of the worm 63 is smaller than the meshing wheel. The equivalent friction angle between the teeth has a self-locking function as a whole.

4-6, an annular positioning ring 621 is protruded from the lower surface of the ring gear 62. The positioning ring 621 is inserted into the bottom plate 611 and the connecting plate 612. The connecting plate 612 and the bottom plate 611 are located on the inner, outer and A number of steel balls 614 are arranged at the bottom to play the role of bearings. Steel balls 614 are also embedded on the upper surface of the ring gear 62, annular protrusions are arranged on both sides of the steel balls 614 for placing butter, and a pressure ring 615 is arranged on the inner side of the cover 613. In the suspended state, the upper and lower steel balls 614 are used to limit the position and reduce friction, so that the overall mechanism runs more smoothly and stably.

4-6 , the connecting plate 612 is provided with a rotating shaft, and the driven dimension is rotatably connected to the rotating shaft, and a limit wheel 66 is disposed on the back of the rack 65 for guiding and limiting. A limiting block 616 abutting against the upper surface of the rack 65 is fixed on the cover 613 to prevent the rack 65 from being in series up and down.

The implementation principle of the above embodiment is as follows: through the balance beam 1, the hoisting point of the crane and the hoisting point of the workpiece are not in the same vertical direction, so as to change the hoisting point of the workpiece, and then the workpiece can be hoisted to a predetermined position. The relative position of the workpiece is finely adjusted by the lifting hoist 4 and the adjusting hoist 5, thereby reducing the difficulty and danger of construction.

Embodiment 3: Referring to Figures 7-10, a method for on-site installation of a shield machine is mainly used for the assembly of a middle trolley behind the shield machine. The figure shows the No. 2 trolley of the shield machine. Specific steps are as follows:

The first step is to place the left and right parts in the well in advance and support them. During the lowering process, move closer to both sides as much as possible.

The second step is to put the middle part into the well and raise it to make sure that all the trolleys are at the same height.

The third step is to hang the lifting hoist 4 on the mobile lifting lug 3 on the ground, and set four lifting hoists 4 on one side. The width of the balance beam 1 is aligned with the width of the wellhead. Hang the hooks of hoist 4 on the left and right parts.

4 lifting hoists 4 are used together to adjust the posture of the left part or the right part. Due to the accuracy error of the bolt connection is 1 mm, and the length, width and height of the shield machine parts are all between 2 meters and 18 meters. At the same time, the error of 1 mm cannot be controlled by lifting; secondly, because the left and right parts are in the air, their posture is very difficult to control. The conventional method is to weld guide ribs or supports, and slowly step by step through jacks or chain hoists Adjustment can make the position of the bolt butt surface fit flat and the bolt holes are aligned, which greatly affects the progress, and at the same time, the construction is difficult and the risk factor is high. Therefore, when the left part is connected with the right part and the middle part by bolts, the left part or the right part can be adjusted in front and rear heights and left and right heights through the above-mentioned four hoists 4, so that the bolt holes can be quickly aligned. Minimize assembly difficulty and further ensure construction safety.

The fourth step is to connect the two ends of the adjusting hoist 5 to the left and right parts to prevent huge shaking when the left and right parts are lifted off the ground, thereby avoiding potential safety hazards and damage to the workpiece.

Step 5: Adjust the position of the movable lifting lugs 3 so that the distance between the movable lifting lugs 3 at both ends is larger than that of the middle part.

After the left part and the right part are lifted off the ground, slowly loosen the adjusting hoist 5, and the left part and the right part are far away from each other. When the left part and the right part move to the limit position, the distance between the left part and the right part is greater than The middle part avoids interference; when the left part and the right part are lifted to the specified height, at this time, the adjustment hoist 5 is tightened to make the left part and the right part approach each other, and the posture is adjusted with the lifting hoist 4, so that the left part and the The right part can be adjusted in place simply by hoisting.

Step 6. After the left and right parts are hung with the hoist 4, carry out a trial lifting to check whether the balance beam 1 is in a horizontal state after the left and right parts are lifted off the ground, and then further fine-tune the main lifting lug through the driving device 2, so that the balance beam 1 is in a horizontal state.

Due to the density of the left and right parts, the error of the hanging point and the difference between the components, there will be a certain error in the weight and the center of gravity, and the balance beam 1 will be inclined to one end at this time, which will cause a great safety hazard.

Step 7. After all the work is ready, 8 people are needed to pull the lifting hoist 4 and 1 person to pull the adjusting hoist 5 at the same time, so that the left part and the right part are butted with the middle part.

Embodiment 4, referring to FIG. 11, the balance hoisting device described in Embodiment 1 can also be used to assemble the No. 1 trolley. Taking the upper layer of the No. 1 trolley as an example, the same method is used to assemble the left and right sides of the No. 1 trolley upper layer. The parts are put into the well, and then the balance beam 1 is put into the well according to the method of Example 2, and it is docked with the left and right parts of the No. 1 trolley, and the position of the left and right parts of the No. 1 trolley is adjusted according to the method of Example 2, Then dock with the lower level of the No. 1 trolley.

Embodiment 5, referring to FIG. 12, the balance hoisting device described in Embodiment 1 can also be used to assemble the platforms of No. 3-5 trolleys. In the same way, the platform is put into the well in advance, and then the platform is put into the well in advance according to the method described in Embodiment 2. The plan is to put the balance beam 1 into the well and dock it with the platform, and adjust the posture and position of the left and right platforms according to the method of Example 2, so that the platform and the main structure of 3-5 trolleys are docked.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (7)

1. A balance hoisting device applied to shield machine site installation is characterized in that: comprising balance beam (1), main lifting lug (2) located on balance beam (1) and below balance beam (1) There are two sets of mobile lifting lugs (3) stacked in a pile, a number of hoisting hoists (4) are suspended on the mobile lifting lugs (3), and a connecting seat (33) is fixed on the lower surface of the balance beam (1), The movable lifting lug (3) is slidably connected in the connecting seat (33), the balance beam (1) is provided with a screw rod (35) for adjusting the movable lifting lug (3), and the balance beam (1) A stopper (36) is welded on, the screw rod (35) passes through the stopper (36) and two nuts are screwed together. 2. The balance hoisting device applied to the on-site installation of a shield machine according to claim 1, characterized in that: a limit plate (34) is slidably provided in the connecting seat (33), and the movable lifting lug (3) ) comprises a sliding plate (32) and a lifting ring plate (31), the sliding plate (32) and the limiting plate (34) are provided with mutual clamping grooves and projections, and the connecting seat (33) is threaded A limit bolt used for abutting against the limit plate (34) is connected; when the position of the movable lifting lug (3) is adjusted, it is locked by the limit plate (34). 3. The balance hoisting device applied to on-site installation of a shield machine according to claim 1, characterized in that it further comprises an adjusting hoist (5), which is connected to two hoisting parts. 4. The balance hoisting device applied to the on-site installation of a shield machine according to claim 1, wherein the balance beam (1) is provided with a driving device for driving the main lifting lug (2) to move, and the The driving device comprises a base (61) fixed on the balance beam (1), a ring gear (62) and a worm (63) rotatably arranged on the base (61), and the worm (63) and the ring gear (62) are meshed and arranged The ring gear (62) is internally meshed with a transmission gear, the base (61) is slidably provided with a rack (65), and the rack (65) is meshed with the transmission gear, and the rack (61). 65) is fixedly connected with the main lifting lug (2), and one end of the worm (63) is provided with a motor (67) for driving the worm (63) to rotate; When the motor (67) drives the worm (63) to rotate, it drives the ring gear (62) to rotate, the ring gear (62) drives the driven gear (64) to rotate, and the driven gear (64) drives the rack (65) to move . 5. The balance hoisting device applied to the on-site installation of a shield machine according to claim 4, wherein the base (61) comprises a bottom plate (611) fixed on the balance beam (1), and is connected to the balance beam (1) by bolts A connecting plate (612) on the bottom plate (611) and a cover (613) fixed on the connecting plate (612) by bolts, a positioning ring (621) protrudes from the lower surface of the ring gear (62), the positioning The ring (621) is inserted into the connecting plate (612) and the bottom plate (611), and several steel balls (614) are provided on the inner side, outer side and bottom surface of the positioning ring (621) and the upper surface of the ring gear (62), The steel balls (614) are all rolled on the base (61). 6. A method for on-site installation of a shield machine, characterized in that: applying the balance hoisting device described in any one of claims 1-5 comprises the following steps: 10. Lift the left part and the right part of the shield machine trolley to go down the well respectively; 20. Hoist the middle part of the trolley of the shield machine down the well; 30. Align the short side of the balance beam (1) with the short side of the wellhead and go down the well, then rotate it 90 degrees, and then connect the hooks of the left and right hoists to the left and right parts respectively; 40. Hang the two ends of the adjusting hoist (5) on the left and right parts respectively; 50. Manually pull the hoist (4) at the same time, adjust the hoist (4) and the adjusting hoist (5), so that the left part and the right part are lifted off the ground at the same time and docked with the middle part, and finally fixed with bolts. 7. The on-site installation method of a shield machine according to claim 6, characterized in that: between steps 40 and 50, the following steps are further included: 41. Adjust the spacing between the mobile lifting lugs (3) on the left and right sides, so that after the left part and the right part are off the ground, the spacing in the middle is larger than the structure of the middle part; 42. After the hoist (4) is hooked, carry out trial lifting, and move the lifting lug (3) by fine-tuning, so that the balance beam (1) is in a horizontal state.

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