Modular crane of fixed hoisting mechanism and operation method of modular crane

Abstract

The modular crane comprises a bridge frame, a moving trolley, a lifting hook device and a lifting device, a cavity for the moving trolley to move is formed in the middle of the bridge frame, rails are installed on the two sides in the cavity respectively, the moving trolley is installed on the rails, and the lifting device is installed on the upper side of the bridge frame. A fixed pulley set is installed on the moving trolley, a guide wheel set is installed on the side face, located at one end of the track, in the cavity, and the hook device is located below the moving trolley. The problems that a traditional crane is large in structural space requirement, the limiting range caused by the limiting position of a lifting hook is large, the distance between trolley tracks is limited by the lifting height and the lifting weight, the actual working position of the lifting hook cannot meet the field working condition requirement, and safety and reliability are poor are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cranes, and in particular to a modular crane with a fixed lifting mechanism and an operating method thereof. Background Art

[0002] Most existing bridge cranes use a lifting trolley structure that combines a lifting mechanism, a fixed pulley device and a trolley. Due to the space requirements of the lifting drum and the fixed pulley group, this structure will limit the distance between the main and auxiliary hooks and the left and right extreme positions of the hook. At the same time, the distance between the trolley tracks will also be limited by the lifting height. The actual working position of the hook often cannot meet the working conditions on site, resulting in erroneous operations such as crooked pulling and slanting, causing certain safety hazards. In response to the above problems, a modular crane with a fixed lifting mechanism is proposed. In addition, the main hook or auxiliary hook of a traditional bridge crane uses a steel wire rope. When the steel wire rope breaks, the heavy object will fall directly, posing a great safety risk. Summary of the invention

[0003] In order to solve the current technical problems, the main purpose of the present invention is to provide a modular crane with a fixed lifting mechanism and an operation method thereof, which solves the problems of large structural space requirements of traditional cranes, large restrictions caused by hook spacing and left and right extreme positions of hooks, trolley track spacing limited by the lifting height and lifting weight, the actual working position of the hook cannot meet the on-site working conditions and has poor safety and reliability.

[0004] The technical solution adopted by the present invention is: a modular crane with a fixed lifting mechanism, including a bridge, a mobile trolley, a hook device and a lifting device, the bridge having a cavity in the middle for the mobile trolley to move, tracks are installed on both sides of the cavity, the mobile trolley is installed on the track, the lifting device is installed on the upper side of the bridge, a fixed pulley block is installed on the mobile trolley, a guide wheel block is installed on the side of the cavity at one end of the track, the hook device is located below the mobile trolley, one end of two lifting cables is wound and connected with the lifting device, the other ends of the two lifting cables pass around the guide wheel block, then pass around the fixed pulley block, then pass around the hook device downward, and then pass around the fixed pulley block upward, and then are connected and fixed to the side of the bridge at the other end of the track; wherein the lifting cable is wound between the fixed pulley block and the hook device at least once.

[0005] The lifting device includes a first winch unit, the guide wheel group includes two first guide wheels, the fixed pulley group includes at least four first fixed pulleys, the hook device includes at least two first movable pulleys, the first hook assembly is connected and fixed to the central axis of the first movable pulley, the lifting rope includes a first steel wire rope, there are two first steel wire ropes, one end of the two first steel wire ropes is wound and connected with the first winch unit, and the other ends pass through the two first guide wheels respectively, and then pass around the two first fixed pulleys respectively, and then pass around the two first movable pulleys respectively, and then pass around the other two first fixed pulleys respectively, and finally connect and fix to the side of the cavity at the other end of the track.

[0006] The lifting device includes a second winch unit, the guide wheel group also includes two second guide wheels, the fixed pulley group also includes at least four second fixed pulleys, the second fixed pulley is located on one side of the first fixed pulley, the hook device also includes at least two second movable pulleys, the second hook assembly is connected and fixed to the central axis of the second movable pulley, the second hook assembly is located on one side of the first hook assembly, the lifting rope also includes a second steel wire rope, there are two second steel wire ropes, one end of the two second steel wire ropes is wound and connected with the second winch unit, and the other end passes through the two second guide wheels respectively, and then passes around the two second fixed pulleys respectively, and then passes around the two second movable pulleys respectively, and then passes around the other two second fixed pulleys respectively, and finally is connected and fixed to the side of the cavity at the other end of the track.

[0007] The bridge frame includes a cross beam and an end beam, the two ends of the two cross beams are respectively connected to the end beams, the two ends of the end beams are respectively installed with first running wheels, the area enclosed by the cross beams and the end beams forms the cavity, and the two cross beams are respectively provided with guide rail seats on one side of the cavity, and the two tracks are respectively installed on the two guide rail seats.

[0008] The mobile trolley includes a vehicle body and a second running wheel. Two second running wheels are respectively installed on both sides of the corresponding track of the vehicle body. The second running wheels drive the vehicle body to move on the track. The fixed pulley group is installed on the vehicle body. A through hole is set on the vehicle body at the position corresponding to the passage of the lifting cable.

[0009] The second traveling wheel is located on the upper side of the vehicle body, the fixed pulley block is installed in the middle of the upper side of the vehicle body, the top of the moving trolley is lower than the upper side of the bridge frame, and the bottom of the moving trolley does not exceed the lower side of the bridge frame.

[0010] A support seat is installed on the top of the bridge frame, and a lifting device is installed on the support seat.

[0011] Buffers are also installed at both ends of the end beam.

[0012] A balancing device is installed on the side where the lifting cable is connected to the bridge frame. The balancing device includes a fixed hinge seat and a movable hinge seat. The fixed hinge seat is fixedly installed on the bridge frame, and the movable hinge seat is hinged to the fixed hinge seat through a rotating shaft. The two lifting cables are respectively connected to the two ends of the movable hinge seat.

[0013] An operating method is used for a modular crane with a fixed lifting mechanism, and the operating method comprises the following steps: Install the main rail at the location where the crane needs to be installed, hoist the crane onto the main rail, and the first running wheels of the bridge located at both ends of the end beam fall on the main rails on both sides respectively, and the bridge moves on the main rails through the first running wheels; The moving trolley moves on the track through the second running wheel. When the moving trolley moves along the track, the lifting rope on one side of the guide wheel group and the lifting rope on the other side are shortened and lengthened respectively, so that the height of the hook device remains unchanged; When the lifting device retracts the lifting rope, the lifting rope changes direction through the guide wheel group, and then changes direction again to the hook device through the fixed pulley group. Since the other end of the lifting rope is fixed on the bridge, the hook device moves up; when the lifting device releases the lifting rope, the hook device moves down; Two lifting cables are wound around the hook device. When one of the lifting cables breaks, the other lifting cable can still keep the hook device stable.

[0014] The present invention has the following beneficial effects: 1. The bridge of the present invention can travel on the track of a building or structure. The hook device is connected to the mobile trolley through a lifting cable, and the heavy object is lifted by the hook device. A longitudinal cavity is provided inside the track, and a track is installed inside the cavity. The mobile trolley can move along the length direction of the bridge through the track, and the lifting device is used to retract and release the lifting cable to lift or put down the heavy object. Since the mobile trolley is located in the cavity of the bridge, and only a fixed pulley block is installed on the mobile trolley, the position of the hook device can be adjusted according to actual needs, and the position of the hook device can be closer to the edge of the mobile trolley, so that the extreme position of the hook device can be made very small. In addition, the lifting cable adopts the above-mentioned winding method. When one of the lifting cables breaks, the other lifting cable can still keep the hook device stable, and the safety and reliability are good.

[0015] 2. The mobile trolley of the present invention can pass through the bottom of the lifting device, and a through hole is provided on the vehicle body at a position corresponding to the position where the lifting cable passes through. The through hole is not only used for the lifting cable to pass through, but also the upper part of the hook device can enter the through hole when lifting heavy objects, thereby obtaining a greater maximum lifting height.

[0016] 3. The mobile trolley of the present application is only equipped with a fixed pulley block, so that the spacing of the tracks will not change due to changes in the lifting weight or lifting height. Both the bridge and the mobile trolley can be modularly designed and mass-produced. In addition, since the lifting device is installed on the upper side of the bridge, when the size of the lifting device changes, the safety and anti-collision requirements of the crane width can be met by simply adjusting the extension rod of the buffer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0018] Figure 1 It is a schematic diagram of the main structure of the present invention.

[0019] Figure 2 It is a schematic diagram of the top view structure of the present invention.

[0020] Figure 3 It is a side view structural schematic diagram of the present invention.

[0021] Figure 4 This is a schematic diagram of the installation of the first steel wire rope of the present invention.

[0022] Figure 5 This is a schematic diagram of the installation of the second steel wire rope of the present invention.

[0023] In the figure: Bridge frame 10, cross beam 11, guide rail seat 111, end beam 12, first running wheel 13, track 14, guide wheel group 15, first guide wheel 151, second guide wheel 152, support seat 16, buffer 17; A mobile trolley 20, a vehicle body 21, and a second traveling wheel 22; Hook device 30, first movable pulley 31, first hook assembly 32, second movable pulley 33, second hook assembly 34; A fixed pulley set 40, a first fixed pulley 41, and a second fixed pulley 42; A lifting device 50, a first hoisting unit 51, and a second hoisting unit 52; A hoisting rope 60, a first steel wire rope 61, and a second steel wire rope 62; Balancing device 70, fixed hinge seat 71, movable hinge seat 72. DETAILED DESCRIPTION

[0024] Embodiment 1: See also Figure 1-5As shown, a modular crane with a fixed lifting mechanism includes a bridge 10, a moving trolley 20, a hook device 30 and a lifting device 50. The bridge 10 has a cavity in the middle for the moving trolley 20 to move, and tracks 14 are installed on both sides of the cavity. The moving trolley 20 is installed on the track 14, and the lifting device 50 is installed on the upper side of the bridge 10. A fixed pulley block 40 is installed on the moving trolley 20, and a guide wheel block 15 is installed on the side of the cavity at one end of the track 14. The hook device 30 is located below the moving trolley 20, and one end of two lifting cables 60 is wound and connected with the lifting device 50, and the other ends of the two lifting cables 60 pass around the guide wheel block 15, then pass around the fixed pulley block 40, then pass around the hook device 30 downward, and then pass around the fixed pulley block 40 upward, and then are connected and fixed to the side of the bridge 10 located at the other end of the track 14; wherein the lifting cable 60 is wound between the fixed pulley block 40 and the hook device 30 at least once.

[0025] The bridge 10 can travel on the track of a building or structure, and the hook device 30 is connected to the mobile trolley 20 through the lifting cable 60, and the heavy object is lifted by the hook device 30. A longitudinally penetrating cavity is provided inside the track 14, and the track 14 is installed inside the cavity. The mobile trolley 20 can move along the length direction of the bridge 10 through the track 14, and the lifting device 50 is used to retract and release the lifting cable 60 to lift or lower the heavy object. Since the mobile trolley 20 is located in the cavity of the bridge 10, and only the fixed pulley block 40 is installed on the mobile trolley 20, the position of the hook device 30 can be adjusted according to actual needs, and the position of the hook device 30 can be closer to the edge position of the mobile trolley 20, so that the extreme position of the hook device 30 can be made very small.

[0026] Furthermore, the lifting cables 60 adopt the above-mentioned winding method. When one of the lifting cables 60 breaks, the other lifting cable 60 can still keep the hook device 30 stable, and the safety and reliability are good.

[0027] In this embodiment, the crane is provided with a hook, namely the main hook. Figure 1-4 , the specific structure is as follows: The lifting device 50 includes a first winch unit 51, the guide wheel group 15 includes two first guide wheels 151, the fixed pulley group 40 includes at least four first fixed pulleys 41, the hook device 30 includes at least two first movable pulleys 31, the first hook assembly 32 is connected and fixed to the central axis of the first movable pulley 31, the lifting rope 60 includes a first steel wire rope 61, and there are two first steel wire ropes 61. One end of the two first steel wire ropes 61 is wound and connected with the first winch unit 51, and the other end passes through the two first guide wheels 151 respectively, and then passes through the two first fixed pulleys 41 respectively, and then passes through the two first movable pulleys 31 respectively, and then passes through the other two first fixed pulleys 41 respectively, and finally is connected and fixed to the side of the cavity at the other end of the track 14.

[0028] The first hoisting unit 51 includes a motor, a reducer and a hoisting drum, and the wire rope is wound on the hoisting drum. The guide wheel group 15 includes two first guide wheels 151, and the two first guide wheels 151 are rotatably installed on a groove-shaped support through a rotating shaft, and the support is connected and fixed to the bridge frame 10. Similarly, the pulley group 40 can also adopt the same structure.

[0029] exist Figure 5 In the embodiment, six first fixed pulleys 41 are provided, four first movable pulleys 31 are provided, and the first steel wire rope 61 is wound twice between the fixed pulley block 40 and the hook device 30 .

[0030] See also Figure 1-3 The bridge frame 10 includes a cross beam 11 and an end beam 12. The two ends between the two cross beams 11 are respectively connected to the end beams 12. The two ends of the end beams 12 are respectively installed with first running wheels 13. The area enclosed by the cross beam 11 and the end beam 12 forms the cavity. Figure 3 A guide rail seat 111 is provided on one side of the two beams 11 located in the cavity, and the two rails 14 are installed on the two guide rail seats 111 respectively.

[0031] Furthermore, the mobile trolley 20 includes a vehicle body 21 and second running wheels 22. Two second running wheels 22 are respectively installed on both sides of the corresponding track 14 of the vehicle body 21. The second running wheels 22 drive the vehicle body 21 to move on the track 14. The fixed pulley block 40 is installed on the vehicle body 21. A through hole is provided on the vehicle body 21 at a position corresponding to the position through which the lifting cable 60 passes. Through the above structure, the mobile trolley 20 is installed in the cavity of the bridge frame 10.

[0032] Specifically, the second traveling wheel 22 is located on the upper side of the vehicle body 21, and the fixed pulley block 40 is installed in the middle of the upper side of the vehicle body 21 near the two ends. The top of the moving trolley 20 is lower than the upper side of the bridge frame 10, and the bottom of the moving trolley 20 does not exceed the lower side of the bridge frame 10. Through the above structure, the moving trolley 20 can pass through the bottom of the lifting device 50, and a through hole is provided on the vehicle body 21 at the position corresponding to the passage of the lifting cable 60. The through hole is not only used for the lifting cable 60 to pass through, but also used for lifting heavy objects. Figure 1 , the upper part of the hook device 30 can also enter the through hole, thereby obtaining a greater maximum lifting height.

[0033] Furthermore, a support seat 16 is installed on the top of the bridge frame 10 , and the lifting device 50 is installed on the support seat 16 .

[0034] See also Figure 2 Buffers 17 are also installed at both ends of the end beam 12 to buffer the collision of the crane.

[0035] For further information, see Figure 2 A balancing device 70 is installed on the side where the lifting cable 60 is connected to the bridge frame 10. The balancing device 70 includes a fixed hinge seat 71 and a movable hinge seat 72. The fixed hinge seat 71 is fixedly installed on the bridge frame 10. The movable hinge seat 72 is hinged to the fixed hinge seat 71 through a rotating shaft. The two lifting cables 60 are respectively connected to the two ends of the movable hinge seat 72. By setting the balancing device 70, the tension received by the two lifting cables 60 is balanced. When the tension on one of the lifting cables 60 is too large, the movable hinge seat 72 will rotate, so that the tension on the two lifting cables 60 is consistent, thereby improving stability.

[0036] Embodiment 2: On the basis of the first embodiment, a hook, namely, an auxiliary hook, can also be installed on the crane. Figure 1-3 、5, the specific structure is as follows: The lifting device 50 includes a second winch unit 52, the guide wheel group 15 also includes two second guide wheels 152, the fixed pulley group 40 also includes at least four second fixed pulleys 42, the second fixed pulley 42 is located on one side of the first fixed pulley 41, the hook device 30 also includes at least two second movable pulleys 33, the second hook assembly 34 is connected and fixed to the central axis of the second movable pulley 33, the second hook assembly 34 is located on one side of the first hook assembly 32, and the lifting rope 60 also includes a second steel wire rope 62, the second steel wire rope 62 is two, one end of the two second steel wire ropes 62 is wound and connected with the second winch unit 52, and the other end passes through the two second guide wheels 152 respectively, and then passes around the two second fixed pulleys 42 respectively, and then passes around the two second movable pulleys 33 respectively, and then passes around the other two second fixed pulleys 42 respectively, and finally is connected and fixed to the side of the cavity at the other end of the track 14. In this embodiment, the second guide wheel 152 and the first guide wheel 151 can be installed on the same rotating shaft.

[0037] exist Figure 5 In the embodiment, four second fixed pulleys 42 are provided, two second movable pulleys 33 are provided, and the second steel wire rope 62 is wound once between the fixed pulley block 40 and the hook device 30 .

[0038] Embodiment three: An operating method is used for a modular crane with a fixed lifting mechanism, and the operating method comprises the following steps: Install the main rail at the location where the crane needs to be installed, hoist the crane onto the main rail, and the first running wheels 13 of the bridge 10 located at both ends of the end beam 12 fall on the main rails on both sides respectively, and the bridge 10 moves on the main rails through the first running wheels 13; The moving trolley 20 moves on the track 14 via the second running wheel 22. When the moving trolley 20 moves along the track 14, the lifting rope 60 on one side of the guide wheel group 15 and the lifting rope 60 on the other side are shortened and lengthened respectively, so that the height of the hook device 30 remains unchanged; When the lifting device 50 retracts the lifting cable 60, the lifting cable 60 is redirected by the guide wheel group 15, and then redirected again to the hook device 30 through the fixed pulley group 40. Since the other end of the lifting cable 60 is fixed on the bridge frame 10, the hook device 30 moves upward; when the lifting device 50 releases the lifting cable 60, the hook device 30 moves downward; Two lifting cables 60 are wound around the hook device 30 . When one of the lifting cables 60 breaks, the other lifting cable 60 can still keep the hook device 30 stable.

[0039] Since the lifting device 50 of the traditional crane is installed on the mobile trolley 20, when the lifting weight becomes larger or the lifting height becomes larger, a larger motor and reducer and a longer winch drum are required, so the width of the mobile trolley 20 will increase, and the spacing of the rails 14 on the bridge frame 10 will be different. However, the mobile trolley 20 of the present invention is only equipped with a fixed pulley group 40, so that the spacing of the rails 14 will not change due to changes in the lifting weight or the lifting height. Both the bridge frame 10 and the mobile trolley 20 can be modularly designed and mass-produced.

[0040] In addition, since the lifting device 50 is installed on the upper side of the bridge 10, when the size of the lifting device 50 changes, the safety and anti-collision requirements of the crane width can be met by simply adjusting the extension rod of the buffer 17.

[0041] The present invention solves the problems of large structural space requirements of traditional cranes, large restriction range caused by the extreme position of the hook, trolley track spacing limited by the influence of the lifting height, the actual working position of the hook unable to meet the requirements of on-site working conditions and poor safety and reliability.

Claims

1. A modular crane with a fixed lifting mechanism, comprising a bridge (10), a moving trolley (20), a hook device (30) and a lifting device (50), characterized in that: The bridge frame (10) has a cavity in the middle for the moving trolley (20) to move, tracks (14) are installed on both sides of the cavity, the moving trolley (20) is installed on the tracks (14), the lifting device (50) is installed on the upper side of the bridge frame (10), the moving trolley (20) is installed with a fixed pulley block (40), a guide wheel block (15) is installed on the side surface at one end of the track (14) in the cavity, the hook device (30) is located below the moving trolley (20), and the two One end of the two lifting cables (60) is wound and connected with the lifting device (50), and the other ends of the two lifting cables (60) are wound around the guide wheel group (15), then around the fixed pulley group (40), then around the hook device (30) downwards, and then around the fixed pulley group (40) upwards, and then connected and fixed to the side of the bridge frame (10) located at the other end of the track (14); wherein the lifting cables (60) are wound between the fixed pulley group (40) and the hook device (30) at least once.

2. A modular crane with a fixed lifting mechanism according to claim 1, characterized in that: The lifting device (50) comprises a first hoisting unit (51), the guide wheel assembly (15) comprises two first guide wheels (151), the fixed pulley assembly (40) comprises at least four first fixed pulleys (41), the hook device (30) comprises at least two first movable pulleys (31), the first hook assembly (32) is connected and fixed to the central axis of the first movable pulley (31), and the lifting rope (60) comprises a first steel wire rope (61), the first steel wire rope (61) is two, one end of the two first steel wire ropes (61) is wound and connected to the first hoisting unit (51), and the other end passes through the two first guide wheels (151), then passes through the two first fixed pulleys (41), then passes through the two first movable pulleys (31), and then passes through the other two first fixed pulleys (41), and finally is connected and fixed to the side surface of the cavity at the other end of the track (14).

3. A modular crane with a fixed lifting mechanism according to claim 2, characterized in that: The lifting device (50) comprises a second hoisting unit (52), the guide wheel assembly (15) further comprises two second guide wheels (152), the fixed pulley assembly (40) further comprises at least four second fixed pulleys (42), the second fixed pulleys (42) are located on one side of the first fixed pulley (41), the hook device (30) further comprises at least two second movable pulleys (33), the second hook assembly (34) is connected and fixed to the central axis of the second movable pulley (33), the second hook assembly (34) is located on the first hook assembly (32), On one side, the hoisting rope (60) further includes a second steel wire rope (62), wherein the second steel wire rope (62) is two in number, one end of the two second steel wire ropes (62) is wound around and connected to the second hoisting unit (52), and the other end passes through two second guide wheels (152) respectively, then passes around two second fixed pulleys (42) respectively, then passes around two second movable pulleys (33) respectively, and then passes around another two second fixed pulleys (42) respectively, and finally is connected and fixed to the side surface at the other end of the track (14) in the cavity.

4. A modular crane with a fixed lifting mechanism according to claim 1, characterized in that: The bridge frame (10) comprises a cross beam (11) and an end beam (12); the two ends of the two cross beams (11) are respectively connected to the end beams (12); the two ends of the end beams (12) are respectively mounted with first running wheels (13); the area enclosed by the cross beams (11) and the end beams (12) forms the cavity; guide rail seats (111) are respectively arranged on one side of the two cross beams (11) located in the cavity; and the two rails (14) are respectively mounted on the two guide rail seats (111).

5. A modular crane with a fixed lifting mechanism according to claim 1 or 4, characterized in that: The mobile trolley (20) comprises a vehicle body (21) and second running wheels (22). Two second running wheels (22) are respectively installed on both sides of the corresponding track (14) of the vehicle body (21). The second running wheels (22) drive the vehicle body (21) to move on the track (14). The fixed pulley block (40) is installed on the vehicle body (21). A through hole is provided on the vehicle body (21) at a position corresponding to the position through which the lifting rope (60) passes.

6. A modular crane with a fixed lifting mechanism according to claim 5, characterized in that: The second traveling wheel (22) is located on the upper side of the vehicle body (21), the fixed pulley block (40) is installed in the middle of the upper side of the vehicle body (21), the top of the moving trolley (20) is lower than the upper side of the bridge frame (10), and the bottom of the moving trolley (20) does not exceed the lower side of the bridge frame (10).

7. The modular crane with a fixed lifting mechanism according to claim 1, characterized in that: A support seat (16) is installed on the top of the bridge frame (10), and a lifting device (50) is installed on the support seat (16).

8. The modular crane with a fixed lifting mechanism according to claim 4, characterized in that: Buffers (17) are also installed at both ends of the end beam (12).

9. The modular crane with a fixed lifting mechanism according to claim 1, characterized in that: A balancing device (70) is installed on the side where the lifting cable (60) is connected to the bridge frame (10), and the balancing device (70) comprises a fixed hinge seat (71) and a movable hinge seat (72). The fixed hinge seat (71) is fixedly installed on the bridge frame (10), and the movable hinge seat (72) is hinged to the fixed hinge seat (71) via a rotating shaft. The two lifting cables (60) are respectively connected to two ends of the movable hinge seat (72).

10. An operating method, characterized in that: The modular crane for a fixed lifting mechanism according to claim 5, the operating method comprises the following steps: Installing a main rail at a location where a crane is to be installed, hoisting the crane onto the main rail, and placing first running wheels (13) of the bridge (10) at both ends of the end beam (12) on the main rails on both sides respectively, so that the bridge (10) moves on the main rails via the first running wheels (13); The moving trolley (20) moves on the track (14) via the second running wheel (22). When the moving trolley (20) moves along the track (14), the lifting rope (60) located on one side of the guide wheel group (15) and the lifting rope (60) located on the other side are shortened and lengthened respectively, so that the height of the hook device (30) remains unchanged; When the lifting device (50) retracts the lifting rope (60), the lifting rope (60) changes direction through the guide wheel group (15), and then changes direction again to the hook device (30) through the fixed pulley group (40). Since the other end of the lifting rope (60) is fixed on the bridge frame (10), the hook device (30) moves upward; when the lifting device (50) releases the lifting rope (60), the hook device (30) moves downward; Two lifting ropes (60) are wound around the hook device (30); when one of the lifting ropes (60) breaks, the other lifting rope (60) can still maintain the stability of the hook device (30).

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