Mining bridge crane

Abstract

The utility model discloses a mining bridge crane, which belongs to the technical field of cranes and comprises two parallel longitudinal beams, a moving trolley is arranged between the two longitudinal beams, two ends of the moving trolley and the corresponding longitudinal beams are arranged in a sliding manner along the front-back direction, and two winch barrels are arranged on the moving trolley along the left-right direction. And the two wringing cylinders are rotationally connected with the moving trolley. The power device drives the winch cylinder to rotate, so that the winch cylinder releases or winds the steel wire rope, the steel wire rope is matched with the movable pulley to lift the lifting hook, the latest winding turn of the steel wire rope on the winch cylinder moves left and right on the winch cylinder along with continuous winding or continuous release of the steel wire rope, and then the lifting hook moves leftwards or rightwards. The lifting hook pulls the free end of the steel wire rope to slide on the movable trolley through the movable pulley, so that the free end of the steel wire rope adapts to the displacement of the lifting hook, the phenomenon that the lifting hook deflects during lifting is avoided, and the phenomenon that the lifting hook is stuck during lifting is prevented.

Description

TECHNICAL FIELD

[0001] The utility model relates to a crane, especially a mine bridge crane. BACKGROUND

[0002] The crane refers to the multi-action hoisting machinery of vertical lifting and horizontal carrying heavy objects in a certain range.

[0003] The existing mine bridge crane generally comprises a moving trolley, a winding drum and a hook, releases or winds the steel wire rope by rotating the winding drum, and then lifts the hook, and then carries the material by the moving trolley to realize the purpose of hoisting the material; when the winding drum is rotated, the latest winding turn of the steel wire rope on the winding drum moves left and right, i.e. moves left and right along the length direction of the winding drum, and then the hook moves left or right when continuously lifting or falling; but the free end of the steel wire rope is fixed on the moving trolley, and when the hook moves left and right, the hook is deflected due to the limitation of the free end of the steel wire rope, which causes the material to be unstable when hoisted, and the hook is easily detached from the track groove of the driven pulley due to the deflection of the hook, which causes the hook to be stuck and unable to lift, and even causes production accidents. SUMMARY

[0004] The utility model discloses a mine bridge crane, which has the advantages of stable lifting of the hook, effectively solves the problem of unstable lifting of the hook in the prior art, and sometimes gets stuck.

[0005] The utility model adopts the following technical scheme: a mine bridge crane comprises two parallel longitudinal beams, a moving trolley is arranged between the two longitudinal beams, the two ends of the moving trolley are slidably arranged along the front-back direction with respect to the corresponding longitudinal beam, two winding drums are arranged on the moving trolley along the left-right direction, and the two winding drums are rotatably connected to the moving trolley; a steel wire rope is wound around each winding drum, the free end of the steel wire rope passes through a hook provided with a driven pulley and is slidably arranged on the moving trolley, and the steel wire rope is drivingly connected to the driven pulley of the hook.

[0006] Further, the free end of the steel wire rope is fixedly provided with an anchor block, a fixed plate is fixedly arranged in the moving trolley along the left-right direction, the fixed plate is symmetrically arranged between the two winding drums, two through grooves are formed in the fixed plate along the left-right direction, and the free end of each steel wire rope is slidably arranged in the corresponding through groove through the anchor block along the left-right direction.

[0007] Further, the inner side wall of the through groove is provided with a T-shaped groove along the length direction of the through groove, and the front and rear sides of the anchor block are fixedly provided with fixed shafts, the outer ends of each fixed shaft are rotatably connected with a roller, the fixed shafts pass through the corresponding T-shaped grooves, and the rollers are located in the corresponding T-shaped grooves.

[0008] Further, the outer end of each fixed shaft protrudes from the outer side of the roller and is fixedly provided with two connecting plates, the outer end of each connecting plate is fixedly provided with a cleaning mechanism, and the lower end surface of the fixed plate is provided with two groups of blanking holes.

[0009] Further, the cleaning mechanism comprises a cleaning plate fixedly arranged at the outer end of the connecting plate, the outer side of the cleaning plate is fixedly provided with a cleaning block in contact with the inner bottom wall of the T-shaped groove, and the outer side of the cleaning block is in contact with the inner side wall of the T-shaped groove.

[0010] Further, the hook comprises a gourd body and a hook head rotatably connected to the lower end of the gourd body, a movable pulley is rotatably connected in the gourd body, two windows are symmetrically arranged on the gourd body, and a steel wire rope passes through the windows and is in transmission connection with the movable pulley.

[0011] Further, the limiting body comprises a fixed ring and two fixed blocks fixed on the fixed ring, each fixed block is fixedly arranged with the gourd body, and the fixed blocks are located on both sides of the window; the steel wire rope passes through the fixed ring and is in transmission connection with the movable pulley.

[0012] Further, the moving trolley comprises a frame body, the two ends of the fixed plate are fixedly arranged with the frame body, and the two ends of the two winding drums are rotatably connected with the frame body.

[0013] Further, the power device comprises a servo motor fixedly arranged on the left and right side surfaces of the frame body, and the output shaft of each servo motor is fixedly arranged with a corresponding winding drum.

[0014] Further, the upper end surface of the frame body is fixedly provided with two moving bodies through a connecting body, a plurality of moving wheels are rotatably connected in the two moving bodies, the upper end surface of each longitudinal beam is fixedly provided with a guide rail in the front and rear directions, each moving body is slidably connected with a corresponding guide rail through a moving wheel, the outer surface of each moving body is fixedly provided with a moving motor, and the output shaft of each moving motor is fixedly arranged with a corresponding moving wheel.

[0015] The utility model discloses a movable trolley, winding drum, steel wire rope, movable pulley and lifting hook are set, when using the device, the winding drum is rotated through the power device, makes the winding drum release or wind the steel wire rope, and the steel wire rope is lifted the lifting hook through the cooperation of movable pulley, realizes the purpose of hoisting material and carrying through movable trolley, when rotating the winding drum, with the continuous winding or continuous release of steel wire rope, the latest winding turn of steel wire rope on the winding drum moves left and right on the winding drum, and then makes the lifting hook move left or right when continuously lifting or continuously falling, and the free end of steel wire rope is slid on movable trolley through the dragging of movable pulley lifting hook, to make the free end of steel wire rope adapt to the displacement of lifting hook, thereby avoiding the phenomenon of deflection when lifting hook lifting, avoiding the phenomenon of the steel wire rope from the track groove of movable pulley and preventing the occurrence of the jamming phenomenon when lifting hook lifting.

[0016] Two, the utility model discloses a connecting plate, cleaning plate and cleaning block are set, when using the device, when the anchor block moves left and right, the anchor block is rolled in the corresponding T -shaped groove through the fixed shaft, and the fixed shaft drives the cleaning plate and cleaning block to move left and right in the T -shaped groove through the connecting plate, so that the cleaning block cleans the inner bottom wall of the T -shaped groove, when the cleaning block moves to the corresponding blanking hole, the dust collected by the cleaning block falls down from the blanking hole, and the purpose of cleaning in the T -shaped groove is realized. ACCURACY OF DRAWINGS

[0017] Figure 1 It is the whole three -dimensional structure schematic diagram of the utility model;

[0018] Figure 2 It is the front view structure schematic diagram of the utility model;

[0019] Figure 3 It is the movable trolley three -dimensional structure schematic diagram in the utility model;

[0020] Figure 4 It is the frame three -dimensional structure schematic diagram in the utility model;

[0021] Figure 5 It is the winding drum three -dimensional structure schematic diagram in the utility model;

[0022] Figure 6 It is the lifting hook three -dimensional structure schematic diagram in the utility model;

[0023] Figure 7 It is the fixed plate internal three -dimensional structure schematic diagram in the utility model;

[0024] Figure 8 It is the fixed plate and anchor block three -dimensional structure schematic diagram of mutual cooperation in the utility model;

[0025] Figure 9 It is the anchor block three -dimensional structure schematic diagram in the utility model;

[0026] Figure 10 It is T-shaped groove three-dimensional structure schematic view of the fixed plate in the utility model;

[0027] Figure 11 It is blanking hole three-dimensional structure schematic view of the fixed plate in the utility model.

[0028] In the drawing, 1, longitudinal beam;2, moving trolley;3, winding drum;4, steel wire rope;5, movable pulley;6, lifting hook;7, anchor block;8, fixed plate;9, through groove;10, T-shaped groove;11, fixed shaft;12, roller;13, connecting plate;14, blanking hole;15, cleaning plate;16, cleaning block;17, gourd body;18, hook head;19, window;20, fixed ring;21, fixed block;22, frame body;23, servo motor;24, connecting body;25, moving body;26, moving wheel;27, guide rail;28, moving motor;29, stand column. DETAILED DESCRIPTION

[0029] Please refer to Figures 1-11 , the following will be described in detail with the utility model in combination with the drawings and examples:

[0030] The mine bridge crane, the utility model discloses a two parallelly arranged longitudinal beam 1, be provided with moving trolley 2 between two longitudinal beam 1, and the both ends of moving trolley 2 are with corresponding longitudinal beam 1 along the front and back direction sliding arrangement, and moving trolley 2 is provided with two winding drums 3 along the left and right direction, and two winding drums 3 are all rotationally connected with moving trolley 2, and each winding drum 3 is provided with steel wire rope 4, and the free end of steel wire rope 4 passes through the lifting hook 6 that is provided with movable pulley 5 and is slidingly arranged with moving trolley 2, and steel wire rope 4 is transmission connection with the movable pulley 5 of lifting hook 6, when using, through power device drive winding drum 3 rotation, make winding drum 3 release or wind steel wire rope 4, and steel wire rope 4 is lifted lifting hook 6 through the cooperation of movable pulley 5, realize the purpose of lifting material and carrying through moving trolley 2, when rotating winding drum 3, with the continuous winding or continuous release of steel wire rope 4, the latest winding turn of steel wire rope 4 on winding drum 3 will move left and right on winding drum 3, and then make lifting hook 6 move left or right when continuously lifting or continuously falling, because the crane of the application is used in the occasion of mine, is the main transport equipment that contacts underground and ground, so the lifting range of lifting hook 6 is relatively large, and the length of winding drum 3 needs to be relatively long, so the distance of lifting hook 6 when continuously lifting or continuously falling left or right is relatively long, when lifting hook 6 moves left or right, lifting hook 6 pulls the free end of steel wire rope 4 on moving trolley 2 to slide through movable pulley 5, to make the free end of steel wire rope 4 adapt to the displacement of lifting hook 6.

[0031] In the embodiment, the free end of the steel wire rope 4 is fixedly provided with an anchor block 7, and a fixed plate 8 is fixedly arranged in the moving trolley 2 along the left-right direction. The fixed plate 8 is located at a symmetrical position between the two winding drums 3, and the fixed plate 8 is provided with two through grooves 9 along the left-right direction. The free end of each steel wire rope 4 is slidably arranged in the corresponding through groove 9 along the left-right direction through the anchor block 7. When the lifting hook 6 moves left or right during continuous lifting or continuous landing, the lifting hook 6 pulls the free end of the steel wire rope 4 to move through the movable pulley 5, and the free end of the steel wire rope 4 drives the anchor block 7 to slide in the corresponding through groove 9, so that the free end of the steel wire rope 4 adapts to the left-right movement of the lifting hook 6.

[0032] In the embodiment, the inner side wall of the through groove 9 is provided with a T-shaped groove 10 along the length direction of the through groove 9, and the front and back sides of the anchor block 7 are fixedly provided with a fixed shaft 11. The outer end of each fixed shaft 11 is rotatably connected with a roller 12. The fixed shaft 11 penetrates through the corresponding T-shaped groove 10, and the roller 12 is located in the corresponding T-shaped groove 10. When the free end of the steel wire rope 4 moves left and right, the steel wire rope 4 drives the anchor block 7 to move left and right, and the anchor block 7 drives the roller 12 to roll in the corresponding T-shaped groove 10 through the fixed shaft 11, so as to realize the purpose of sliding the module left and right in the through groove 9.

[0033] In normal use, dust is easily accumulated in the T-shaped groove 10, which affects the rolling of the roller 12, and even causes the roller 12 to be stuck after a long time, so that the free end of the steel wire rope 4 cannot adapt to the left-right movement of the lifting hook 6, and needs to be stopped for maintenance. In order to avoid this problem:

[0034] In the embodiment, the outer end of each fixed shaft 11 protrudes from the outer side of the roller 12 and is fixedly provided with two connecting plates 13. The outer end of each connecting plate 13 is fixedly provided with a cleaning mechanism. When the anchor block 7 moves left and right, the anchor block 7 drives the roller 12 to roll in the corresponding T-shaped groove 10 through the fixed shaft 11, and at the same time, the fixed shaft 11 drives the cleaning mechanism to move left and right in the T-shaped groove 10 through the connecting plate 13, so that the cleaning mechanism cleans the inner bottom wall of the T-shaped groove 10. The left and right sides of the lower end surface of the fixed plate 8 are provided with two groups of blanking holes 14. Each group of blanking holes 14 is two and located at the front and back ends of the through groove 9 and communicates with the corresponding T-shaped groove 10. When the anchor block 7 drives the two cleaning mechanisms to move left and right through the fixed shaft 11, the cleaning mechanism moves to the corresponding blanking hole 14, and the dust collected by the cleaning mechanism falls from the blanking hole 14, so as to realize the purpose of cleaning in the T-shaped groove 10, and avoid the phenomenon of roller 12 being stuck in use.

[0035] In this embodiment, the cleaning mechanism includes a cleaning plate 15 fixedly arranged at the outer end of the connecting plate 13, the outer side of the cleaning plate 15 is fixedly provided with a cleaning block 16 in contact with the inner bottom wall of the T-shaped groove 10, and the outer side of the cleaning block 16 is in contact with the inner side wall of the T-shaped groove 10. During use, when the anchor block 7 moves left and right, the anchor block 7 drives the roller 12 to roll in the corresponding T-shaped groove 10 through the fixed shaft 11, and the fixed shaft 11 drives the cleaning plate 15 to move left and right in the T-shaped groove 10 through the connecting plate 13. The cleaning plate 15 drives the cleaning block 16 to move in the T-shaped groove 10, so that the cleaning block 16 cleans the inner bottom wall of the T-shaped groove 10. When the cleaning block 16 moves to the corresponding blanking hole 14, the collected dust of the cleaning block 16 falls from the blanking hole 14, achieving the purpose of cleaning the T-shaped groove 10.

[0036] In daily use, the dust in the T-shaped groove 10 can be cleaned by the cleaning plate 15 and the cleaning block 16 during the usual lifting operation. However, the collected dust of the cleaning plate 15 and the cleaning block 16 can only fall from the blanking hole 14 when the cleaning plate 15 and the cleaning block 16 move to the blanking hole 14. Therefore, the T-shaped groove 10 can be cleaned regularly. The operation method is as follows: rotate the winch 3 to release the steel wire rope 4, so that the lifting hook 6 moves downward and to one side of the moving trolley 2, and then the free end of the steel wire rope 4 drives the anchor block 7 to move to one side of the moving trolley 2. The anchor block 7 drives the cleaning plate 15 and the cleaning block 16 to move to one end of the T-shaped groove 10 through the fixed shaft 11, so that the cleaning plate 15 and the cleaning block 16 clean and collect the dust inside the T-shaped groove 10. Until the free end of the steel wire rope 4 moves to the blanking hole 14, the dust inside the T-shaped groove 10 falls from the blanking hole 14 under the pushing of the cleaning block 16, achieving the purpose of cleaning the inside of the T-shaped groove 10. Then, reverse the winch 3 to wind the steel wire rope 4, until the free end of the steel wire rope 4 moves to the blanking hole 14 on the other side of the T-shaped groove 10, so that the dust in the T-shaped groove 10 falls from the blanking hole 14, finally completing the cleaning of the T-shaped groove 10.

[0037] When the movable pulley 5 of the lifting hook 6 drives the anchor block 7 to move left and right through the free end of the steel wire rope 4, the steel wire rope 4 is easy to come off the track groove of the movable pulley 5, which is not convenient for transmission and is easy to cause the lifting hook 6 to be stuck. In order to solve this problem:

[0038] In the embodiment, the hook 6 comprises a gourd body 17 and a hook head 18 rotatably connected to the lower end of the gourd body 17, a movable pulley 5 is rotatably connected in the gourd body 17, two windows 19 are symmetrically formed on the gourd body 17, the steel wire rope 4 passes through the windows 19 and is in transmission connection with the movable pulley 5; a limiting body is fixedly arranged on the outer surface of the gourd body 17 at the position corresponding to the window 19, the steel wire rope 4 can pass through the limiting body and be in transmission connection with the movable pulley 5; when the hook 6 moves left and right, the hook 6 applies force to the steel wire rope 4 through the gourd body 17, the movable pulley 5 and the limiting body, and then the free end of the steel wire rope 4 drives the anchor block 7 to move left and right, and the steel wire rope 4 can be prevented from being separated from the track groove of the movable pulley 5 due to the existence of the limiting body.

[0039] In the embodiment, the limiting body comprises a fixed ring 20 and two fixed blocks 21 fixed on the fixed ring 20, each fixed block 21 is fixedly arranged on the gourd body 17 and located on the two sides of the window 19; the steel wire rope 4 passes through the fixed ring 20 and is in transmission connection with the movable pulley 5; when the hook 6 moves left and right, the hook 6 drives the fixed ring 20 to move left and right through the gourd body 17, the fixed ring 20 drives the anchor block 7 to move left and right through the steel wire rope 4, and the fixed ring 20 limits the steel wire rope 4 to prevent the steel wire rope 4 from being separated from the track groove of the movable pulley 5.

[0040] In the embodiment, the moving trolley 2 comprises a frame body 22, the two ends of the fixed plate 8 are fixedly arranged on the frame body 22, and the two ends of the two winches 3 are rotatably connected to the frame body 22; the power device comprises two servo motors 23 fixedly arranged on the left and right sides of the frame body 22, the output shaft of each servo motor 23 is fixedly arranged on the corresponding winch 3; the servo motor 23 drives the corresponding winch 3 to rotate, so as to realize the winding and releasing of the winch 3 to the steel wire rope 4; the upper end surface of the frame body 22 is fixedly provided with two moving bodies 25 through a connecting body 24, a plurality of moving wheels 26 are rotatably connected in each moving body 25, the upper end surface of each longitudinal beam 1 is fixedly provided with a guide rail 27 in the front-rear direction, and each moving body 25 is slidably connected to the corresponding guide rail 27 through the moving wheel 26; the outer surface of each moving body 25 is fixedly provided with a moving motor 28, and the output shaft of each moving motor 28 is fixedly arranged on the corresponding moving wheel 26; in use, the moving motor 28 drives the moving wheel 26 to rotate, so that the moving body 25 slides on the corresponding guide rail 27, and then the frame body 22 is driven to move forward and backward through the connecting body 24, thereby achieving the purpose of driving the frame body 22 to move forward and backward.

[0041] Each longitudinal beam 1 is fixedly arranged on the upper part of the side wall in the workshop in the front-rear direction, so that the moving trolley 2 can move forward and backward on the upper part of the workshop, thereby achieving the purpose of hoisting materials; each longitudinal beam 1 can also be supported on the ground through a stand column 29, and the moving trolley 2 can also move forward and backward in the workshop to achieve the purpose of hoisting materials.

[0042] The utility model discloses a working principle: when using, through servo motor 23 drive winch 3 rotation, make winch 3 release or wind steel wire rope 4, and steel wire rope 4 passes through the cooperation of movable pulley 5 and lifts lifting hook 6, realize hoisting material and through the mobile trolley 2 and carry the purpose of, when rotating winch 3, with the continuous winding or continuous release of steel wire rope 4, the latest winding turn of steel wire rope 4 on winch 3 will move on winch 3 left and right, and then make lifting hook 6 move left or right when continuously lifting or continuously falling, when lifting hook 6 moves left or right, lifting hook 6 moves the free end of steel wire rope 4 through movable pulley 5 and pulls, and the free end of steel wire rope 4 drives anchor block 7 to slide in corresponding through groove 9, to make the free end of steel wire rope 4 adapt the left and right movement of lifting hook 6, anchor block 7 simultaneously through fixed shaft 11 and drive cleaning plate 15 and cleaning block 16 move in T groove 10, make cleaning plate 15 and cleaning block 16 clean and collect the dust in T groove 10, until the free end of steel wire rope 4 moves to any material dropping hole 14, make the dust in T groove 10 fall from material dropping hole 14 under the push of cleaning block 16, realize the purpose of cleaning in T groove 10.

Claims

1. A mining bridge crane characterized in that: The utility model provides a kind of movable trolley for steel wire rope, including two parallelly arranged longitudinal beams (1), mobile trolley (2) is arranged between two longitudinal beams (1), the both ends of mobile trolley (2) are slidably arranged with corresponding longitudinal beam (1) along front-back direction, two winches (3) are arranged on mobile trolley (2) along left-right direction, two winches (3) are rotatably connected with mobile trolley (2);Steel wire rope (4) is wound and arranged on each winch (3), the free end of steel wire rope (4) is slidably arranged with mobile trolley (2) through the hook (6) that is provided with movable pulley (5), steel wire rope (4) is drivingly connected with the movable pulley (5) of hook (6), further include power device, power device is used to drive winch (3) rotation.

2. A mining bridge crane according to claim 1, characterised in that: The free end of the steel wire rope (4) is fixedly provided with an anchor block (7), and the mobile trolley (2) is fixedly provided with a fixed plate (8) along the left-right direction. The fixed plate (8) is located at the symmetrical position between the two winches (3). The fixed plate (8) is provided with two through grooves (9) along the left-right direction. The free end of each steel wire rope (4) is slidably arranged in the corresponding through groove (9) through the anchor block (7) along the left-right direction.

3. A mining bridge crane according to claim 2, characterised in that: The inner side wall of the through groove (9) is provided with a T-shaped groove (10) along the length direction of the through groove (9). The front and back sides of the anchor block (7) are fixedly provided with a fixed shaft (11). The outer end of each fixed shaft (11) is rotatably connected with a roller (12). The fixed shaft (11) passes through the corresponding T-shaped groove (10), and the roller (12) is located in the corresponding T-shaped groove (10).

4. A mining bridge crane according to claim 3, characterised in that: The outer end of each fixed shaft (11) protrudes from the outer side of the roller (12) and is fixedly provided with two connecting plates (13). The outer end of each connecting plate (13) is fixedly provided with a cleaning mechanism. The left and right sides of the lower end surface of the fixed plate (8) are provided with two groups of blanking holes (14). Each group of blanking holes (14) is two and located at the front and back ends of the through groove (9) and is in communication with the corresponding T-shaped groove (10).

5. A mining bridge crane according to claim 4, characterised in that: The cleaning mechanism includes a cleaning plate (15) fixedly connected with the outer end of the connecting plate (13). The outer side of the cleaning plate (15) is fixedly provided with a cleaning block (16) in contact with the inner bottom wall of the T-shaped groove (10). The outer side of the cleaning block (16) is in contact with the inner side wall of the T-shaped groove (10).

6. A mining bridge crane according to claim 1, characterised in that: The hook (6) includes a gourd body (17) and a hook head (18) rotatably connected to the lower end of the gourd body (17). The gourd body (17) is rotatably connected with a movable pulley (5). The gourd body (17) is symmetrically provided with two windows (19) on the upper end. The steel wire rope (4) passes through the window (19) and is drivingly connected with the movable pulley (5). The outer surface of the gourd body (17) is fixedly provided with a limiting body at the position corresponding to the window (19). The steel wire rope (4) can pass through the limiting body and be drivingly connected with the movable pulley (5).

7. A mining bridge crane according to claim 6, characterised in that: The limiting body includes a fixed ring (20) and two fixed blocks (21) fixed on the fixed ring (20). Each fixed block (21) is fixedly provided with the gourd body (17) and located on both sides of the window (19). The steel wire rope (4) passes through the fixed ring (20) and is drivingly connected with the movable pulley (5).

8. A mining bridge crane according to claim 1, characterised in that: The mobile trolley (2) comprises a frame (22), both ends of the fixed plate (8) are fixedly arranged with the frame (22), and both ends of the two winches (3) are rotatably connected with the frame (22).

9. A mining bridge crane according to claim 8, characterised in that: The power device comprises a servo motor (23) fixedly arranged on the left and right sides of the frame (22), and the output shaft of each servo motor (23) is fixedly arranged with the corresponding winch (3).

10. A mining bridge crane according to claim 8, characterised in that: The upper end surface of the frame (22) is fixedly provided with two moving bodies (25) through a connecting body (24), a plurality of moving wheels (26) are rotatably connected in the two moving bodies (25), the upper end surface of each longitudinal beam (1) is fixedly provided with a guide rail (27) in the front-rear direction, and each moving body (25) is slidably connected with the corresponding guide rail (27) through the moving wheel (26); the outer surface of each moving body (25) is fixedly provided with a moving motor (28), and the output shaft of each moving motor (28) is fixedly arranged with the corresponding moving wheel (26).

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