Lifting device

Abstract

The utility model relates to the technical field of tunnel construction, in particular to a hoisting device, which solves the problem that box culvert pieces which are longitudinally transported in a small-diameter shield tunnel in the prior art cannot be laterally hoisted, and comprises a trailer, a box culvert crane is connected onto the trailer in a sliding manner, the box culvert crane comprises a hanging bracket, and a liftable rotating component is connected below the hanging bracket. The lower side of the rotating assembly is connected with a sucker assembly. The box culvert piece lifting device has the advantages that the box culvert piece is grabbed through the suction cup assemblies, the space requirements of the two sides of the box culvert piece are lowered, in other words, lifting of the box culvert piece is not affected by the space sizes of the two sides of the box culvert piece, and lifting of the box culvert piece in a small-diameter tunnel is achieved; after the box culvert piece is hoisted by the box culvert crane, the box culvert piece can be steered through the rotating assembly, so that the box culvert piece can be longitudinally transported in the tunnel, the direction of the box culvert piece is adjusted through the rotating assembly after the box culvert piece is transported in place, and transportation of the box culvert piece in the small-diameter tunnel is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel construction, in particular to a lifting device. Background Art

[0002] In recent years, with the development of shield construction technology, tunnel construction projects have increased significantly. Generally, to fully utilize the tunnel cross-section, shield machines larger than 10 meters often incorporate box culverts underneath the tunnel to serve as passageways for power, communications, drainage, and other pipelines. As construction projects evolve, 6-meter and 8-meter shield machines also require the installation of box culverts underneath the tunnel to route pipelines. Installing box culverts after tunnel excavation is complete is time-consuming and labor-intensive, impacting construction efficiency.

[0003] With the development of shield construction technology, research on synchronous box culvert assembly has gradually emerged. The existing invention patent with authorization announcement number CN106761856A discloses a box culvert crane for synchronous box culvert construction with a shield machine. It includes a crane traveling beam, a traveling trolley, a lifting device, a positioning bracket, and a box culvert bracket. The box culvert bracket is a U-shaped structure. The box culvert bracket is inserted into the box culvert opening through the lifting device, and then the box culvert bracket is lifted to drive the box culvert parts for assembly. When the crane of this invention is lifting the box culvert, the box culvert must be placed horizontally. However, in 7-meter and 8-meter shield projects, the clearance in the trailer is limited, and the box culvert parts are often placed vertically when transporting the box culvert.

[0004] The existing invention patent, CN113979320A, discloses a method and device for lifting monolithic box culvert components. The lifting device moves to the side of the culvert component, grabs the component, and then moves it to the lower part of the connecting bridge, rotating it 90° for assembly. However, this method and device are only suitable for large-diameter shield tunneling projects exceeding 10 meters. Limited clearance within the trailer makes it impossible to lift the box culvert from the side in 7- and 8-meter shield tunneling projects.

[0005] In summary, although certain progress has been made in the research on box culvert cranes in shield-type equipment, it still cannot meet the needs of synchronous assembly of box culverts during 6-meter and 8-meter shield construction, that is, the box culvert components transported longitudinally in small-diameter shield tunnels cannot be lifted from the side. Utility Model Content

[0006] The utility model provides a lifting device, which solves the problem in the prior art that box culverts transported longitudinally in a small-diameter shield tunnel cannot be lifted from the side.

[0007] The technical solution of the present utility model is achieved as follows:

[0008] A lifting device includes a trailer, on which a box culvert crane is slidably connected. The box culvert crane includes a hanger, a liftable rotating assembly is connected below the hanger, and a suction cup assembly is connected to the lower side of the rotating assembly. The box culvert is grabbed by the suction cup assembly, and the box culvert does not need to be lifted by side lifting. That is, the box culvert can be lifted without setting a lateral moving mechanism on the lifting device. The space size on both sides of the box culvert does not affect the lifting of the box culvert, thereby realizing the lifting of the box culvert in a small diameter tunnel; after the box culvert crane lifts the box culvert, the box culvert can be turned by the rotating assembly so that the box culvert can be transported longitudinally in the tunnel. After the box culvert is transported to its designated position, the direction is adjusted by the rotating assembly, which is conducive to the transportation of the box culvert in the small diameter tunnel; the rotating assembly and the suction cup assembly work together to realize the lifting and rotation of the box culvert after longitudinal transportation in the small diameter shield tunnel, thereby realizing the rapid transportation and installation of the box culvert in the small diameter tunnel.

[0009] The suction cup assembly includes a vacuum cup, which is equipped with a vacuum pump and a reservoir tank. The vacuum pump is connected to the reservoir tank via a one-way valve, which in turn is connected to the vacuum cup. A vacuum switch is provided between the reservoir tank and the vacuum cup. The vacuum pump controls the suction force of the reservoir tank via the one-way valve and maintains the vacuum level of the reservoir tank within a certain range. When the vacuum switch is pressed, the suction cup is instantly connected to the vacuum reservoir tank, allowing the culvert to be lifted. When the culvert needs to be released, the vacuum switch is pressed, exposing the suction cup to outside air and releasing the culvert.

[0010] The rotating assembly includes a rotating frame that is rotatably connected to the vacuum suction cup. The rotating frame is equipped with a rotating motor that is connected to the vacuum suction cup via a transmission mechanism. The rotating motor drives the vacuum suction cup to rotate through the transmission mechanism, thereby rotating the box culvert component on the vacuum suction cup, thereby achieving a turning direction for the box culvert component.

[0011] The hanger is provided with a hoisting hoist, which is provided with a hoisting rope. The hanger is provided with a fixed pulley, and the rotating frame is provided with a movable pulley. The hoisting rope passes through the fixed pulley and the movable pulley. The hoisting hoist can adjust the hoisting rope to retract or release the hoisting rope, thereby adjusting the height of the rotating frame to achieve the lifting and lowering of the box culvert.

[0012] The trailer is provided with a running track, and the hanger is provided with a driven trolley and a driving trolley. Both the driven trolley and the driving trolley are provided with roller assemblies that roll in conjunction with the running track. The driven trolley and the driving trolley are simultaneously connected to the running track to ensure the stability of the hanger during movement. The roller assemblies roll on the running track to facilitate the movement of the hanger.

[0013] A chain is provided on the running track, and a sprocket and a drive motor are provided on the driving trolley. The output end of the drive motor is connected to a transmission gear set, which is connected to the sprocket, and the sprocket meshes with the chain. The drive motor can drive the sprocket to rotate through the transmission gear set, thereby providing driving force for the movement of the hanger, thereby achieving the lifting of the box culvert.

[0014] A segment crane is slidably connected to the trailer and positioned in front of the box culvert crane. An interlocking mechanism is provided between the two cranes. The cranes are mounted on a common track with the box culvert crane, with the crane in front and the box culvert crane in the rear. This allows for simultaneous assembly of segments and box culvert components, improving construction efficiency.

[0015] The interlocking mechanism also includes an infrared laser emitter and an infrared laser baffle. The infrared laser emitter is mounted on the segment crane, and the infrared laser baffle is mounted on the box culvert crane, with the infrared laser emitter and infrared laser baffle corresponding to each other. When the segment crane and the box culvert crane are a certain distance apart, the infrared laser is reflected by the sensor, and the segment crane or the box culvert crane begins to slow down, preventing the segment crane and the box culvert crane from colliding due to untimely braking.

[0016] The interlocking mechanism includes a lever and a cross limit switch. The lever is mounted on the box culvert crane, and the cross limit switch is mounted on the segment crane. The lever and the cross limit switch work together. When the box culvert crane and the segment crane reach their limit distance, the lever on the box culvert crane shifts the cross limit switch on the segment crane, stopping the crane's movement.

[0017] The segment crane and the box culvert crane are each equipped with an electric control cabinet, and both are connected to the power supply via a busbar. Both the segment crane and the box culvert crane are powered by the busbar to prevent the segment crane's connecting cable from interfering with the box culvert crane.

[0018] The beneficial effects of the utility model are as follows: first, the box culvert parts are grabbed by the suction cup assembly, which reduces the space requirements on both sides of the box culvert parts, that is, the space size on both sides of the box culvert parts does not affect the lifting of the box culvert parts, thereby realizing the lifting of the box culvert parts in small-diameter tunnels; after the box culvert crane lifts the box culvert parts, the box culvert parts can be turned by the rotating assembly, so that the box culvert parts can be transported longitudinally in the tunnel, and the direction of the box culvert parts is adjusted by the rotating assembly after the box culvert parts are transported to the right position, which is conducive to the transportation of the box culvert parts in the small-diameter tunnel; the rotating assembly and the suction cup assembly work together to realize the lifting and rotation of the box culvert parts after longitudinal transportation in the small-diameter shield tunnel, thereby realizing the rapid transportation and installation of the box culvert parts in the small-diameter tunnel.

[0019] The horizontal movement mechanism on the lifting device is eliminated, and the lifting device only needs to move forward and backward, and the suction cup is raised and lowered and rotated to complete the lifting and installation of the box culvert parts. During the lifting process of the box culvert parts, there is no need for the suction cup to move left and right, which simplifies the lifting structure and lifting process and improves the lifting efficiency.

[0020] A segment crane and a box culvert crane are installed on the trailer at the same time, and the segment crane and the box culvert crane are set on a common track, so that the segments and box culvert components can be installed and constructed at the same time, improving construction efficiency; in addition, both the segment crane and the box culvert crane are powered by busbars to avoid the connection cable of the segment crane interfering with the box culvert crane.

[0021] An interlocking mechanism is set between the box culvert crane and the segment crane. When the segment crane and the box culvert crane are at a certain distance from each other, the segment crane or the box culvert crane starts to slow down to avoid collision between the segment crane and the box culvert crane due to untimely braking; when the box culvert crane and the segment crane reach the limit distance, the interlocking mechanism controls the segment crane or the box culvert crane to stop moving to ensure the safety of lifting and avoid collision. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a working diagram of a lifting device of the utility model;

[0024] Figure 2 This is a schematic diagram of the lifting device structure;

[0025] Figure 3 This is the side view of the box culvert hoisting;

[0026] Figure 4 This is a schematic diagram of the box culvert crane structure;

[0027] Figure 5 This is the front view of the connection between the suction cup assembly and the box culvert;

[0028] Figure 6 for Figure 5 The enlarged schematic diagram of point Ⅰ in the middle;

[0029] Figure 7 It is a top view of the connection between the suction cup assembly and the box culvert;

[0030] Figure 8 This is a schematic diagram of the box culvert crane drive component structure.

[0031] In the figure: 1. trailer, 2. marshalling car, 3. box culvert parts, 5. segment crane, 6. box culvert crane, 7. busbar, 8. rotating assembly, 9. vacuum pump, 10. solenoid valve, 11. vacuum switch, 12. vacuum gauge, 13. vacuum suction cup, 14. driven trolley, 15. hanger, 16. wire rope hoist, 17. electric control cabinet, 18. connecting device, 19. driving trolley, 21. infrared laser transmitter, 22. infrared laser baffle, 23. lever, 24. cross limit switch, 25. running track, 26. roller group, 27. chain, 28. sprocket, 29. transmission gear group, 81. rotating frame, 82. rotating motor. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1, as Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 As shown, a lifting device includes a trailer 1, on which a box culvert crane 6 is slidably connected. The box culvert crane 6 includes a hanger 15, and a retractable rotating assembly 8 is connected below the hanger 15. The lower side of the rotating assembly 8 is connected to a suction cup assembly. The trailer 1 is used to carry the shield machine's supporting equipment. The box culvert crane 6 can move on the trailer 1 to lift the box culvert parts 3. During construction, the materials such as the pipe segments and box culvert parts 3 required for the shield construction process are transported to the designated location by the marshaling vehicle 1. After the box culvert parts 3 are transported to the designated location, the crane 15 lowers the suction cup assembly and grabs the box culvert parts 3 by vacuum adsorption. After the grabbing is completed, the box culvert parts 3 are lifted to a certain height. Then the hanger 15 moves on the trailer 1 to lift the box culvert parts 3. After the box culvert parts 3 are lifted to the designated location, the rotating assembly 8 adjusts the direction of the box culvert parts 3 to facilitate the installation of the box culvert parts 3.

[0034] Among them, using the suction cup assembly to grab the box culvert part 3 can effectively reduce the space requirement on both sides of the box culvert part 3, that is, the space size on both sides of the box culvert part 3 does not affect the lifting of the box culvert part 3, and the lifting of the box culvert part 3 in a small-diameter tunnel is realized; after the box culvert crane 6 lifts the box culvert part 3, the box culvert part 3 can be turned by the rotating assembly 8, so that the box culvert part 3 can be transported longitudinally in the tunnel. After the box culvert part is transported to its place, the direction is adjusted by the rotating assembly 8, which is conducive to the transportation of the box culvert part 3 in a small-diameter tunnel;

[0035] Furthermore, the suction cup assembly includes a vacuum cup 13, which is equipped with a vacuum pump 9 and a reservoir tank. The vacuum pump 9 is connected to the reservoir tank via a one-way valve, which in turn communicates with the vacuum cup 13. A vacuum switch 11 is provided between the reservoir tank and the vacuum cup. The vacuum switch 11 is a vacuum relay. The vacuum pump 9 controls the suction force of the reservoir tank via the one-way valve and maintains the vacuum level of the reservoir tank within a certain range. The vacuum switch 11 is connected to a solenoid valve 10, which controls the communication between the reservoir tank and the vacuum cup 13, or between the vacuum cup 13 and the outside air. In the event of a sudden power outage, the solenoid valve 10 will not change its position, thus avoiding the risk of the box culvert 3 suddenly falling and improving construction safety.

[0036] Specifically, when the vacuum switch 11 is pressed, the vacuum suction cup 13 is instantly connected to the vacuum storage tank. At this time, the vacuum suction cup 13 is adsorbed on the surface of the box culvert part 3, which can lift the box culvert part 3; when the box culvert part 3 needs to be released, the vacuum switch 11 is pressed, the vacuum suction cup 13 comes into contact with the outside air, and the box culvert part 3 will be released.

[0037] Furthermore, a vacuum gauge 12 is connected to the vacuum cup 13. This gauge displays the pressure between the cup 13 and the box culvert component 3, providing real-time monitoring of the cup 13's suction force on the box culvert component 3 and further ensuring construction safety. When the vacuum cup 13 is in use, the exposed sealing strip has a maximum compression compensation of approximately 20 mm. Prior to suction, the pre-compression of the strip depends on the weight of the cup 13 itself. The surface flatness of the box culvert component 3 is controlled within 2 mm / m to ensure a tight seal between the cup 13 and the box culvert component 3.

[0038] Example 2, based on Example 1, a lifting device, such as Figure 5 、 Figure 6 、 Figure 7 As shown, the rotating assembly 8 includes a rotating frame 81, which is rotatably connected to the vacuum suction cup 13. A rotating motor 82 is mounted on the rotating frame 81 and connected to the vacuum suction cup 13 via a transmission mechanism. The rotating frame 81 and the vacuum suction cup 13 are connected via a rolling bearing. The rotating motor 82 drives the vacuum suction cup 13 to rotate via the transmission mechanism, thereby rotating the box culvert 3 on the vacuum suction cup 13, thereby achieving a desired rotation of the box culvert 3. In this embodiment, the transmission mechanism is a gear and ring transmission mechanism. The gear ring is mounted on the vacuum suction cup 13, and the gear is mounted at the output end of the rotating motor 82. The gear and the gear ring mesh, and the rotating motor 82 can drive the gear to rotate, thereby driving the gear ring to rotate, thereby achieving rotation of the vacuum suction cup 13.

[0039] Furthermore, a hoisting hoist 16 is provided on the hanger 15, and a hoisting rope is provided on the hoisting hoist 16. A fixed pulley is provided on the hanger 15, and a movable pulley is provided on the rotating frame 81. The hoisting rope passes through the fixed pulley and the movable pulley. In this embodiment, the hoisting rope is a steel wire rope. Two fixed pulleys are provided on the left and right sides of the hanger 15, and a movable pulley is provided on the left and right sides of the rotating frame 81. The fixed pulleys and the movable pulleys are positioned in a one-to-one correspondence. The hoisting rope alternately passes through the fixed pulleys and the movable pulleys. The hoisting hoist 16 is used to retract or release the hoisting rope, thereby achieving the raising and lowering of the rotating frame 81.

[0040] Furthermore, the trailer 1 is provided with a running track 25, and the hanger 15 is provided with a driven trolley 14 and a driving trolley 19. Both the driven trolley 14 and the driving trolley 19 are provided with a roller assembly 26, which rolls in conjunction with the running track 25. The driven trolley 14 and the driving trolley 19 are simultaneously connected to the running track 25 to ensure the stability of the hanger 15 during movement. The roller assembly 26 rolls on the running track 25 to facilitate the movement of the hanger 15.

[0041] Further, if Figure 8 As shown, a chain 27 is provided on the running track 25, and a sprocket 28 and a drive motor are provided on the driving trolley 19. The output end of the drive motor is connected to a transmission gear set 29, which is connected to the sprocket 28, and the sprocket 28 meshes with the chain 27. The chain 27 is mounted on the lower flange plate of the running track 25. The drive motor can drive the sprocket 28 to rotate through the transmission gear set 29. The cooperation between the sprocket 28 and the chain 27 provides driving force for the movement of the hanger 15, thereby lifting the box culvert member 3. Specifically, the transmission gear set 29 is a single-stage spur gear transmission. The driving trolley 19 can drive the driven trolley 14 to move synchronously on the running track 25, thereby moving the box culvert crane 6 on the running track 25 to lift the box culvert member 3.

[0042] Example 3, based on Example 2, a lifting device, such as Figure 1 、 Figure 2 As shown, a segment crane 5 is slidably connected to the trailer 1. The segment crane 5 is located in front of the box culvert crane 6, and an interlocking mechanism is provided between the segment crane 5 and the box culvert crane 6. The segment crane 5 and the box culvert crane 6 are arranged on the same track, with the segment crane 5 in front and the box culvert crane 6 in the back, meeting the working requirement of synchronous assembly of the segments and box culvert components 3 and improving construction efficiency.

[0043] Furthermore, the interlocking mechanism also includes an infrared laser emitter 21 and an infrared laser baffle 22. The infrared laser emitter 21 is installed on the segment crane 5, and the infrared laser baffle 22 is installed on the box culvert crane 6, with the infrared laser emitter 21 corresponding to the infrared laser baffle 22. When the distance between the segment crane 5 and the box culvert crane 6 is reduced to a certain distance, the infrared laser is reflected, the sensor recognizes the signal, and the segment crane 5 or the box culvert crane 6 begins to slow down, avoiding collisions caused by untimely braking of the segment crane 5 and the box culvert crane 6.

[0044] Furthermore, the interlocking mechanism includes a lever 23 and a cross limit switch 24. The lever 23 is provided on the box culvert crane 6, and the cross limit switch 24 is provided on the segment crane 5. The lever 23 cooperates with the cross limit switch 24. When the distance between the box culvert crane 6 and the segment crane 5 is reduced to the limit distance, the lever 23 on the box culvert crane 6 activates the cross limit switch 24 on the segment crane 5, causing the segment crane 5 or the box culvert crane 6 to move, thus preventing collision between the segment crane 5 and the box culvert crane 6.

[0045] Further, if Figure 3 、 Figure 4 As shown, the segment crane 5 and the box culvert crane 6 are each equipped with an electric control cabinet 17, and both the segment crane 5 and the box culvert crane 6 are connected to a power source via a busbar 7. As the segment crane 5 or the box culvert crane 6 moves, the electric control cabinet 17 moves with it, and power is supplied to the segment crane 5 or the box culvert crane 6 via the busbar 7. This eliminates the need to install a tow bar on the trailer 1 to supply power to the segment crane 5 or the box culvert crane 6. As the segment crane 5 or the box culvert crane 6 moves forward and backward, it carries the electric control cabinet 17 with it, reducing the impact of cable extension on the synchronous assembly of the box culvert during crane movement. This allows for the simultaneous assembly of the segment crane and the box culvert components 3, thereby improving work efficiency.

[0046] like Figure 1 As shown, the lifting process of the box culvert component 3 is as follows: the marshalling car 2 transports the longitudinally placed box culvert component 3 to the operating area of ​​the box culvert crane 6, and moves the box culvert crane 6 backward to the top of the box culvert component 3 to be assembled. After the pipe segments on the marshalling car 2 are lifted, the box culvert crane 6 grabs the box culvert component 3 on the marshalling car 2 through the vacuum suction cup 13, lifts the box culvert component 3 to a certain height, and then moves forward to the box culvert rotation area under the connecting bridge, driving the box culvert component 3 to rotate 90° to a horizontal state, and then assembles the box culvert component 3. After the assembly is in place, the box culvert is released, and this process is repeated for the subsequent box culvert components 3.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lifting device, comprising a trailer (1), a box culvert crane (6) being slidably connected to the trailer (1), characterized in that: The box culvert crane (6) includes a hanger (15), a liftable rotating assembly (8) is connected below the hanger (15), and a suction cup assembly is connected to the lower side of the rotating assembly (8).

2. The lifting device according to claim 1, characterized in that: The suction cup assembly includes a vacuum suction cup (13), a vacuum pump (9) and a storage tank are provided on the vacuum suction cup (13), the vacuum pump (9) is connected to the storage tank through a one-way valve, the storage tank is communicated with the vacuum suction cup (13), and a vacuum switch (11) is provided between the storage tank and the vacuum suction cup (13).

3. The lifting device according to claim 2, characterized in that: The rotating assembly (8) includes a rotating frame (81), the rotating frame (81) is rotatably connected to the vacuum suction cup (13), and a rotating motor (82) is provided on the rotating frame (81), and the rotating motor (82) is connected to the vacuum suction cup (13) through a transmission mechanism.

4. The lifting device according to claim 3, characterized in that: The hanger (15) is provided with a hoisting hoist (16), the hoisting hoist (16) is provided with a lifting rope, the hanger (15) is provided with a fixed pulley, the rotating frame (81) is provided with a movable pulley, and the lifting rope passes through the fixed pulley and the movable pulley.

5. The lifting device according to any one of claims 2 to 4, characterized in that: The trailer (1) is provided with a running track (25), the hanger (15) is provided with a driven trolley (14) and a driving trolley (19), and the driven trolley (14) and the driving trolley (19) are both provided with a roller group (26), and the roller group (26) and the running track (25) are in rolling cooperation.

6. The lifting device according to claim 5, characterized in that: A chain (27) is provided on the running track (25), a sprocket (28) and a driving motor are provided on the active trolley (19), an output end of the driving motor is connected to a transmission gear set (29), the transmission gear set (29) is connected to the sprocket (28), and the sprocket (28) is meshed with the chain (27).

7. The lifting device according to any one of claims 1 to 4 and 6, characterized in that: A segment crane (5) is slidably connected to the trailer (1), and the segment crane (5) is located in front of the box culvert crane (6). An interlocking mechanism is provided between the segment crane (5) and the box culvert crane (6).

8. The lifting device according to claim 7, characterized in that: The interlocking mechanism further includes an infrared laser emitter (21) and an infrared laser baffle (22), wherein the infrared laser emitter (21) is arranged on the segment crane (5), and the infrared laser baffle (22) is arranged on the box culvert crane (6), and the infrared laser emitter (21) corresponds to the infrared laser baffle (22).

9. The lifting device according to claim 8, characterized in that: The interlocking mechanism includes a shift lever (23) and a cross limit switch (24), wherein the shift lever (23) is arranged on the box culvert crane (6), and the cross limit switch (24) is arranged on the segment crane (5), and the shift lever (23) cooperates with the cross limit switch (24).

10. The lifting device according to claim 8 or 9, characterized in that: The segment crane (5) and the box culvert crane (6) are respectively provided with an electric control cabinet (17), and the segment crane (5) and the box culvert crane (6) are both connected to a power supply via a busbar (7).

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