CN115783669A - Lifting and translating device - Google Patents

Abstract

The invention belongs to the technical field of rail transit, and discloses a lifting translation device which comprises a sliding rail, a base, a supporting seat, a lifting mechanism and a shifting mechanism. The slip track extends in a first direction. The base is arranged on the sliding track in a sliding mode. Elevating system presss from both sides and locates between base and the supporting seat, and elevating system can drive the supporting seat and remove along the second direction for the base, the first direction of second direction perpendicular to. The shifting mechanism comprises a shifting rack, a shifting gear and a shifting driver, the shifting rack is arranged on the sliding track and extends along the first direction, the shifting driver is arranged on the base, and the shifting gear is arranged at the output end of the shifting driver and meshed with the shifting rack. According to the invention, the lifting mechanism is used for lifting or lowering the bogie on the supporting seat, and the shifting mechanism is used for translating the base and the supporting seat. Because the cooperation degree of aversion gear and aversion rack is high for when the base removes for the track that slides, steady controllable is difficult for rocking.

Description

Lifting and translation device

Technical Field

The invention relates to the technical field of rail transit, in particular to a lifting translation device.

Background

The motor car bogie is arranged between the motor car body and the motor car track and is used for bearing the weight of the motor car body and assisting the motor car body to steer. When the bogie has a fault, the bogie and the bullet train rail below the bogie need to be detached together and replaced.

At present, the bogie needs to be lifted and translated when being replaced, and in a patent document with application publication number of CN114803940A, a straddle type monorail bogie lifting and translating mechanism is disclosed, which is arranged in a foundation pit and comprises a lifting device and a traveling assembly which are connected with each other. The lifting device comprises a lifting platform and a lifting assembly arranged on the lifting platform, and the lifting assembly adopts a transmission structure of a lead screw nut to raise or lower the height of a fault bogie on the lifting platform; the walking assembly comprises wheels, and the wheels are matched with walking rails laid on the bottom surface of the foundation pit to realize translation of the whole mechanism. During the use, dismantle trouble bogie get off, install on lift platform, then utilize lifting unit to reduce its height, walk to walk the subassembly and drive its driven vehicle track side and move ground one side after that, use lifting unit to rise it to ground height at last, the staff of being convenient for pushes out or hangs away trouble bogie.

However, the bogie has a large mass, and in the process of driving the bogie to translate by the traveling assembly, the traveling assembly is easy to shake during translation only by means of the matching of the wheels and the traveling rails, so that the bogie falls off.

Disclosure of Invention

The invention aims to provide a lifting translation device which can translate a bogie stably and is safe and reliable.

In order to achieve the purpose, the invention adopts the following technical scheme:

lifting and translation device, wherein, include:

a slip track extending in a first direction;

the base is arranged on the sliding track in a sliding mode;

a supporting base;

the lifting mechanism is clamped between the base and the supporting seat, and can drive the supporting seat to move along a second direction relative to the base, wherein the second direction is perpendicular to the first direction;

the shifting mechanism comprises a shifting rack, a shifting gear and a shifting driver, the shifting rack is arranged on the sliding track and extends along the first direction, the shifting driver is arranged on the base, and the shifting gear is arranged at the output end of the shifting driver and meshed with the shifting rack.

Optionally, be provided with two gibs on the track that slides, the gib is followed the first direction extends, two the gib is followed the third direction interval and is set up, the third direction perpendicular to the first direction with the second direction, be provided with two sets of leading wheels on the base, it is two sets of leading wheel one-to-one sets up in two on the gib.

Optionally, two the gib block is first gib block and second gib block respectively, set up in on the first gib block the leading wheel is first leading wheel, it is provided with first guide way to encircle along circumference on the first leading wheel, contained angle between the cell wall of first guide way and the tank bottom is the obtuse angle, first gib block support lean on in the cell wall and the tank bottom of first guide way.

Optionally, the guide wheel arranged on the second guide strip is a second guide wheel, a second guide groove is circumferentially arranged on the second guide wheel in a surrounding manner, an included angle between a groove wall and a groove bottom of the second guide groove is a right angle, and the second guide strip abuts against the groove wall and the groove bottom of the second guide groove.

Optionally, the base includes first support and second support that interconnect, first support is followed first direction extends, is provided with two, the second support presss from both sides and locates between two first support, every be provided with a set of leading wheel on the first support, the driver that shifts sets up in on the second support.

Optionally, the base further includes a wheel seat, two wheel seats are provided on each first support, two guide wheels are rotatably provided on each wheel seat, a group of guide wheels is formed by four guide wheels on each first support, and the guide wheels and the lifting mechanism are provided on two opposite sides of the wheel seats.

Optionally, the supporting seat includes a supporting plate and two supporting frames arranged at intervals, the supporting plate is connected to the lifting mechanism, and the supporting frames are arranged on one side of the supporting plate, which deviates from the base.

Optionally, the lifting mechanism includes a screw rod, a transmission member and a lifting driver, the output end of the lifting driver is connected to the transmission member, the transmission member is rotatably connected to the supporting seat, one end of the screw rod is connected to the base, the other end of the screw rod is screwed to the transmission member and penetrates through the supporting seat, and the length direction of the screw rod is parallel to the second direction.

Optionally, the transmission part comprises a worm wheel and a worm, the worm wheel is meshed with the worm, the worm wheel is in threaded connection with the screw rod, and the worm is connected to the output end of the lifting driver.

Optionally, the sliding track includes two track beams extending along the first direction, the two track beams are disposed at intervals in a third direction, the third direction is perpendicular to the first direction and the second direction, the displacement driver is provided with two, an output end of each displacement driver is connected with one displacement gear, each displacement gear is provided with one displacement rack, and the two displacement racks are disposed in opposite directions and are respectively disposed on the two track beams.

The invention has the beneficial effects that:

the invention provides a lifting translation device which comprises a sliding rail, a base, a supporting seat, a lifting mechanism and a shifting mechanism. The lifting mechanism is clamped between the base and the supporting seat, and can drive the supporting seat to move along the second direction relative to the base, so that the bogie on the supporting seat is lifted or lowered. The sliding track is provided with a shifting rack extending along the first direction, the base is provided with a shifting driver, and the output end of the shifting driver is connected with a shifting gear meshed with the shifting rack. Therefore, when the shifting driver drives the shifting gear to rotate, the base can slide on the sliding track along the first direction under the matching of the shifting gear and the shifting rack, so that the supporting seat is driven to move along the first direction, and the bogie is translated. Because the degree of cooperation of aversion gear and aversion rack is high for when the base removed for the track that slides, steady controllable is difficult for rocking.

Drawings

FIG. 1 is an isometric view of an elevation translation device provided by an embodiment of the present invention;

FIG. 2 is a front view of a lifting translation device provided by an embodiment of the present invention;

FIG. 3 is a schematic view of a screw and a base according to an embodiment of the present invention;

FIG. 4 is a schematic view of the connection between the screw and the support base according to the embodiment of the present invention;

FIG. 5 is an enlarged view of a portion of FIG. 2 at A;

FIG. 6 is a partial enlarged view at B in FIG. 2;

fig. 7 is a schematic view of the connection between the wheel seat and the screw and the guide wheel provided by the embodiment of the invention.

In the figure:

1. a sliding track; 11. a track beam; 12. connecting rails; 13. a cushion block;

2. a base; 21. a first bracket; 22. a second bracket; 23. a wheel seat;

3. a supporting seat; 31. a support plate; 311. avoiding holes; 32. a support frame; 33. a connecting shell;

4. a lifting mechanism; 41. a screw; 42. a lift drive; 43. a lifting speed reducer;

5. a displacement mechanism; 51. a shifting rack; 52. a shift gear; 53. a shift driver; 54. a shift reducer;

6. a guide assembly; 61. a first guide wheel; 62. a second guide wheel; 63. a first guide bar; 64. a second guide bar;

7. an electric cabinet.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention. It should be further noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings, not all of them.

In the description of the present invention, unless otherwise explicitly specified or limited, the terms "connected," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integral to one another; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description of the present embodiment, the terms "upper", "lower", "right", etc. are used in an orientation or positional relationship based on that shown in the drawings only for convenience of description and simplicity of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used only for descriptive purposes and are not intended to be limiting.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

The motor car bogie is arranged between the motor car body and the motor car track and is used for bearing the weight of the motor car body and assisting the motor car body to steer. When the bogie breaks down, the motor car can be parked on the movable track bridge, then the bogie and the movable track bridge below the bogie are jointly disassembled, the bogie descends into a foundation pit below the movable track bridge, the movable track bridge moves to the edge of the foundation pit, and finally the movable track bridge ascends to the ground, so that a worker can conveniently push away the movable track bridge for maintenance.

As shown in fig. 1 and fig. 2, the present embodiment provides a lifting and translating device, which includes a sliding track 1, a base 2, a supporting seat 3, a lifting mechanism 4, and a shifting mechanism 5. The slip track 1 extends in a first direction. The base 2 is slidably disposed on the sliding track 1. The lifting mechanism 4 is clamped between the base 2 and the supporting seat 3, and the lifting mechanism 4 can drive the supporting seat 3 to move along a second direction relative to the base 2, wherein the second direction is perpendicular to the first direction. The displacement mechanism 5 includes a displacement rack 51, a displacement gear 52, and a displacement driver 53. The shift rack 51 is provided on the slide rail 1 and extends in the first direction. The shift driver 53 is disposed on the base 2, and the shift gear 52 is mounted on an output end of the shift driver 53 and engaged with the shift rack 51.

During the use, elevating system 4 presss from both sides and locates between base 2 and the supporting seat 3, can drive supporting seat 3 and remove along the second direction for base 2 to realize that the bogie on the supporting seat 3 risees or reduces. The sliding track 1 is provided with a displacement rack 51 extending along a first direction, the base 2 is provided with a displacement driver 53, and an output end of the displacement driver 53 is connected to a displacement gear 52 engaged with the displacement rack 51. Therefore, when the shift driver 53 drives the shift gear 52 to rotate, under the cooperation of the shift gear 52 and the shift rack 51, the base 2 slides on the sliding track 1 along the first direction, and then drives the support seat 3 to move along the first direction, so as to realize the translation of the bogie. Due to the high matching degree of the shifting gear 52 and the shifting rack 51, the base 2 is stable and controllable when moving relative to the sliding track 1, and is not easy to shake.

The following is a description of the overall structure of the lifting translation device provided in this embodiment.

As shown in fig. 1, the lifting and translating device comprises a sliding track 1, a base 2, a supporting seat 3, a lifting mechanism 4, a shifting mechanism 5, a guiding assembly 6 and an electric cabinet 7. Wherein the support base 3 is used for supporting the bogie and a movable track bridge below the bogie.

As shown in fig. 3, the base 2 includes a first bracket 21, a second bracket 22, and a wheel base 23. First support 21 is provided with two, all extends along the first direction, and two first supports 21 interval settings in the third direction, and first direction, second direction and third direction are two liang of perpendicular. The second bracket 22 is clamped between the two first brackets 21, and the length direction of the second bracket 22 is parallel to the third direction. The wheel seat 23 is disposed on the first support 21, and two wheel seats 23 are disposed on each first support 21. In this embodiment, the wheel seat 23 has a plate shape.

As shown in fig. 3 and 4, the lifting mechanism 4 includes a screw 41, a transmission member, and a lifting driver 42. The output end of the lifting driver 42 is connected to the transmission member, the transmission member is rotatably connected to the supporting seat 3, one end of the screw rod 41 is connected to the wheel seat 23, the other end of the screw rod is screwed to the transmission member and penetrates through the supporting seat 3, and the length direction of the screw rod 41 is parallel to the second direction. When the lifting driver 42 drives the transmission member to rotate, the transmission member drives the supporting seat 3 to move on the screw rod 41 along the second direction, so that the bogie on the supporting seat 3 is lifted or lowered. Specifically, the transmission member includes a worm wheel and a worm, the worm wheel is engaged with the worm, the worm wheel is screwed to the screw rod 41, the worm is connected to the output end of the lifting driver 42, and the worm wheel and the worm are matched to convert the rotation direction of the output end of the lifting driver 42, so that the supporting seat 3 is conveniently lifted and lowered. In this embodiment, the second direction is a vertical direction.

The number of the lifting drivers 42 in this embodiment is four, the output end of each lifting driver 42 is connected with a transmission member, each transmission member is matched with a screw rod 41, and each screw rod 41 is correspondingly connected with one wheel seat 23. The four screws 41 share the pressure of the supporting seat 3 and the bogie on the supporting seat 3, and under the combined action of the four lifting drivers 42, the supporting seat 3 is lifted stably relative to the base 2, and the bogie on the supporting seat 3 is not easy to topple. Illustratively, lift drive 42 is a servo motor.

Furthermore, the lifting mechanism 4 further comprises a lifting reducer 43, and the lifting driver 42 is connected with the worm through the lifting reducer 43 to reduce the rotation speed of the worm and protect the lifting driver 42.

Further, as shown in fig. 1 and 2, the supporting seat 3 includes a supporting plate 31, a connecting shell 33, and two supporting frames 32 arranged at intervals, an avoiding hole 311 is formed in the supporting plate 31, the screw rod 41 penetrates through the avoiding hole 311, and a worker can stand on the supporting plate 31 to disassemble and assemble the steering frame. The connecting shell 33 is disposed on the supporting plate 31, and the transmission member is disposed in the connecting shell 33 and rotatably connected to the connecting shell 33. The support frame 32 is arranged on one side of the support plate 31 departing from the base 2, and the two support frames 32 respectively support two movable track beams below the bogie. In this embodiment, the supporting seat 3 further includes an inclined strut, and the inclined strut is supported between the supporting plate 31 and the supporting frame 32, so that the supporting frame 32 is stable in structure and good in supporting effect.

As shown in fig. 1, the sliding rail 1 is laid on the bottom surface of the foundation pit, and includes two rail beams 11, a connecting rail 12 and a cushion block 13, the two rail beams 11 are all extended along a first direction, and the two rail beams 11 are spaced apart from each other in a third direction. The connecting rails 12 are sandwiched between the two track beams 11, and the length direction is parallel to the third direction, and are used for connecting the track beams 11, so that the track beams 11 are stable in position. Cushion 13 sets up in the bottom of track roof beam 11 for the levelness of adjustment track roof beam 11 guarantees the security of this lift translation device when the translation. Illustratively, the cushion block 13 is provided with a plurality of, and the cushion block 13 adopts metallic iron to make, and hardness is big, and the support effect is good.

As shown in fig. 2 and 3, the displacement mechanism 5 includes two displacement racks 51, two displacement gears 52, and two displacement drivers 53, wherein the two displacement racks 51 extend in the first direction, are respectively disposed on the two track beams 11, and are disposed opposite to each other. Two displacement drivers 53 are arranged on the second support 22 of the base 2, and a displacement gear 52 is connected to the output end of each displacement driver 53, and each displacement gear 52 is engaged with one displacement rack 51. When the shifting driver 53 drives the shifting gear 52 to rotate, the shifting gear 52 drives the base 2 to slide on the sliding track 1 along the first direction under the coordination of the shifting rack 51 on the track beam 11, and further drives the supporting seat 3 to move along the first direction, so that the bogie is translated. Meanwhile, the oppositely arranged shifting racks 51 make the sliding of the base 2 on the sliding track 1 more stable when the two shifting drivers 53 act together. Illustratively, the displacement driver 53 is a servo motor.

Further, the shift mechanism 5 further includes two shift speed reducers 54, and two shift speed reducers 54 are provided, and each of the shift drivers 53 is connected to the shift gear 52 through one of the shift speed reducers 54 to reduce the rotation speed of the shift gear 52, so as to protect the shift drivers 53.

As shown in fig. 2 and 3, the guiding assembly 6 includes two guiding strips and two guiding wheels, the two guiding strips are respectively disposed on the two track beams 11, and the guiding strips extend along the first direction. The leading wheel rotates and sets up on wheel seat 23, is provided with two leading wheels on every wheel seat 23, and four leading wheels on every first support 21 constitute a set of leading wheel, and two sets of leading wheels set up on two gibs one-to-one. When the base 2 slides along the first direction on the sliding track 1, the steering wheel arranged on the base 2 can also rotate along the first direction on the guide bar along with the movement of the base 2, so that the movement of the base 2 is rapid and smooth.

Specifically, as shown in fig. 5, the two guide bars are a first guide bar 63 and a second guide bar 64, the guide wheel disposed on the first guide bar 63 is a first guide wheel 61, a first guide groove is circumferentially disposed on the first guide wheel 61, an included angle between a groove wall and a groove bottom of the first guide groove is an obtuse angle, and the first guide bar 63 abuts against the groove wall and the groove bottom of the first guide groove, so that the first guide bar 63 reliably guides the first guide wheel 61, and the first guide wheel 61 is not prone to deviation. As shown in fig. 6, the guide wheel disposed on the second guide bar 64 is the second guide wheel 62, the second guide groove is circumferentially disposed on the second guide wheel 62, an included angle between a groove wall and a groove bottom of the second guide groove is a right angle, and the second guide bar 64 abuts against the groove wall and the groove bottom of the second guide groove, so that the second guide bar 64 reliably guides the second guide wheel 62, and the second guide wheel 62 is not prone to deviation. Meanwhile, the shapes of the first guide groove and the second guide groove are different, so that the first guide wheel 61 and the second guide wheel 62 are difficult to separate from the corresponding guide strips simultaneously, and the reliability of the guide assembly 6 is further improved.

In this embodiment, as shown in fig. 7, two guide wheels and a screw rod 41 are disposed on two opposite sides of the wheel seat 23, and since the screw rod 41 supports the support seat 3 and the bogie on the support seat 3, the screw rod 41 is disposed on one opposite side of the guide wheels, so that the guide wheels can more directly support the screw rod 41, and damage to the base 2 due to excessive pressure on the screw rod 41 when the screw rod 41 is disposed at other positions on the base 2 is avoided.

Further, the lifting translation device further comprises a first controller, wherein the first controller is electrically connected with the displacement driver 53 and is used for controlling the displacement driver 53 to start and stop, so that the translation position of the base 2 is accurately adjustable. Further, the lifting and translating device further comprises a second controller, wherein the second controller is electrically connected with the lifting driver 42 and is used for controlling the lifting driver 42 to start and stop, so that the lifting height of the supporting seat 3 can be accurately adjusted. The first controller and the second controller are accommodated in the electric cabinet 7, and the electric cabinet 7 is arranged on the base 2, so that the signal receiving and transmitting of the first controller and the second controller are facilitated.

The first controller and the second controller may be the same controller, or may be two controllers which work separately, and the specific structure and control principle thereof are conventional arrangements in the field, and are not described herein again.

Furthermore, the lifting translation device further comprises a remote controller, wherein the remote controller is electrically connected with the first controller and the second controller and is used for starting instructions to the first controller and the second controller so as to remotely control the lifting translation device.

The general process of the lifting translation device provided by the embodiment when in use is as follows:

first, the lifting driver 42 drives the worm to rotate, thereby driving the support plate 31 to ascend to the movable rail bridge position, and using the support frame 32 to carry the disassembled bogie and movable rail bridge.

Then, the lifting driver 42 drives the worm to rotate, so as to drive the support plate 31 to descend to the bottom of the foundation pit, and the bogie is prevented from being blocked by the top of the foundation pit during translation.

Then, the shift driver 53 drives the shift gear 52 to rotate, so as to drive the base 2 to move along the first direction on the sliding track 1 to the edge of the foundation pit.

Finally, the worm is driven to rotate by the lifting driver 42, so that the support plate 31 is driven to rise to the ground level, and a worker can conveniently push out the bogie for maintenance.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Numerous obvious variations, adaptations and substitutions will occur to those skilled in the art without departing from the scope of the invention. This need not be, nor should it be exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (10)

1. Lifting and translation device, its characterized in that includes:

a slip track (1), the slip track (1) extending in a first direction;

the base (2) is arranged on the sliding track (1) in a sliding mode;

a support base (3);

the lifting mechanism (4) is clamped between the base (2) and the supporting seat (3), the lifting mechanism (4) can drive the supporting seat (3) to move along a second direction relative to the base (2), and the second direction is perpendicular to the first direction;

the shifting mechanism (5) comprises a shifting rack (51), a shifting gear (52) and a shifting driver (53), the shifting rack (51) is arranged on the sliding track (1) and extends along the first direction, the shifting driver (53) is arranged on the base (2), and the shifting gear (52) is arranged at the output end of the shifting driver (53) and meshed with the shifting rack (51).

2. The lifting and translation device according to claim 1, characterized in that two guide bars are disposed on the sliding track (1), the guide bars extend along the first direction, the two guide bars are disposed at intervals along a third direction, the third direction is perpendicular to the first direction and the second direction, two sets of guide wheels are disposed on the base (2), and the two sets of guide wheels are disposed on the two guide bars in a one-to-one correspondence manner.

3. The lifting and translation device according to claim 2, characterized in that the two guide bars are a first guide bar (63) and a second guide bar (64), the guide wheel disposed on the first guide bar (63) is a first guide wheel (61), a first guide groove is circumferentially disposed on the first guide wheel (61), an included angle between a groove wall and a groove bottom of the first guide groove is an obtuse angle, and the first guide bar (63) abuts against the groove wall and the groove bottom of the first guide groove.

4. The lifting and translation device according to claim 3, characterized in that the guide wheel disposed on the second guide bar (64) is a second guide wheel (62), a second guide groove is circumferentially disposed on the second guide wheel (62), an included angle between a groove wall and a groove bottom of the second guide groove is a right angle, and the second guide bar (64) abuts against the groove wall and the groove bottom of the second guide groove.

5. Lifting and translation device according to claim 2, characterized in that said base (2) comprises a first bracket (21) and a second bracket (22) connected to each other, said first bracket (21) extending along said first direction and being provided in two, said second bracket (22) being interposed between two of said first brackets (21), each of said first brackets (21) being provided with a set of said guide wheels, said displacement drive (53) being provided on said second bracket (22).

6. The lifting and translating device according to claim 5, wherein the base (2) further comprises wheel bases (23), two wheel bases (23) are disposed on each first support (21), two guide wheels are rotatably disposed on each wheel base (23), four guide wheels on each first support (21) form a group of guide wheels, and the guide wheels and the lifting mechanism (4) are disposed on two opposite sides of the wheel bases (23).

7. Lifting and translation device according to claim 1, characterized in that said support (3) comprises a support plate (31) and two spaced-apart support brackets (32), said support plate (31) being connected to said lifting mechanism (4), said support brackets (32) being arranged on the side of said support plate (31) facing away from said base (2).

8. The lifting and translating device according to claim 1, wherein the lifting mechanism (4) comprises a screw (41), a transmission member and a lifting driver (42), an output end of the lifting driver (42) is connected to the transmission member, the transmission member is rotatably connected to the supporting seat (3), one end of the screw (41) is connected to the base (2), the other end of the screw is screwed to the transmission member and penetrates through the supporting seat (3), and a length direction of the screw (41) is parallel to the second direction.

9. Lifting and translation device according to claim 8, characterized in that said transmission means comprise a worm wheel and a worm, said worm wheel meshing with said worm, said worm wheel being screwed to said threaded rod (41), said worm being connected to the output of said lifting drive (42).

10. The lifting and translating device according to any one of claims 1 to 9, wherein the sliding track (1) comprises two track beams (11) extending along the first direction, the two track beams (11) are spaced apart from each other in a third direction, the third direction is perpendicular to the first direction and the second direction, the two displacement drivers (53) are provided, one displacement gear (52) is connected to an output end of each displacement driver (53), one displacement rack (51) is configured for each displacement gear (52), and the two displacement racks (51) are arranged opposite to each other and are respectively arranged on the two track beams (11).

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