Driven type rail car

By controlling the extension and lifting of the guardrail and movable load-bearing plate through a retractable and liftable screw system, the problem of the inability to adjust the support of existing railcars is solved, and the stable transfer of larger structural components and the improvement of safety are achieved.

CN121608768APending Publication Date: 2026-03-06CSSC NANJING LUZHOU MACHINE
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Patent Information

Application Number
CN202610016041.2
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-01-07
Publication Date
2026-03-06

AI Technical Summary

Technical Problem

The existing driven railcars cannot adjust their load-bearing platforms to meet different needs, resulting in a lack of support when transporting large structural components, which may lead to the components falling off and threatening safety.

Method used

The system employs a retractable and liftable screw system. The screw is driven to rotate via a handwheel, which in turn drives the telescopic screw block and the lift screw block to control the extension and lifting of the guardrail and the movable load-bearing plate, thereby expanding the support surface and ensuring the stable transfer of structural components.

Benefits of technology

It provides stable support for larger structural components, preventing them from falling off and improving safety and stability during transport.

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Abstract

The invention discloses a driven rail car, and relates to the technical field of transfer rail cars, the driven rail car comprises a mounting plate and a plurality of pulley components, a fixed bearing plate is arranged on the upper surface of the mounting plate, two protective fences are symmetrically arranged on the two sides of the mounting plate, and two lead screw mounting seats are symmetrically arranged at the two ends of the lower surface of the mounting plate; movable bearing plates are arranged on the upper surfaces of the two protective fences correspondingly, roller sliding block components are arranged on the sides, close to the mounting plates, of the protective fences correspondingly, jacking lead screw components are arranged at the tops of the sides, close to each other, of the two lead screw mounting bases, and telescopic lead screw components are arranged at the bottoms of the sides, close to each other, of the lead screw mounting bases. By means of the structure, the two protective fences can stretch out through the telescopic lead screw component, then the two movable bearing plates stretch out, the two rolling wheel sliding block components stretch out through the jacking lead screw component, the two movable bearing plates are jacked up, the two movable bearing plates and the fixed bearing plate are located on the same horizontal plane, and a large structural part is better supported; and the stability during transferring is ensured.
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Description

Technical Field

[0001] This invention relates to the field of transfer railcar technology, and more specifically to a driven railcar. Background Technology

[0002] A driven railcar is a type of railcar whose core characteristic is that it does not rely on its own power for propulsion, but is driven by external traction to run on a fixed track to complete tasks such as material transport, personnel transport, or operational assistance. It is usually used as a traction unit, combined with a power locomotive to form a complete working system, and is widely used in railway construction and maintenance, material transportation, and special scenario operations.

[0003] Existing driven railcars, when transferring products in a workshop, often need to transport structural components of different specifications. However, the load-bearing platform of these railcars is usually welded from steel and cannot be adjusted to meet different needs. This results in a lack of support for larger structural components during transport, which may cause them to fall off the railcar, threatening the safety of workers and other equipment in the workshop. Therefore, we propose a driven railcar to solve the problems mentioned above. Summary of the Invention

[0004] The purpose of this invention is to provide a driven railcar to solve the problem mentioned in the background art that existing driven railcars, when transferring products in the workshop, usually need to transfer structural components of different specifications. However, the load-bearing platform of the railcar is usually welded from steel and cannot be adjusted according to different needs. This results in a lack of support for larger structural components during the transfer process, which may cause structural components to fall off the railcar and threaten the safety of workers and other equipment in the workshop.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A driven railcar includes a mounting plate. A fixed load-bearing plate is provided on the upper surface of the mounting plate. Two guardrails are symmetrically arranged on both sides of the mounting plate. Two screw mounting seats are symmetrically arranged at both ends of the lower surface of the mounting plate. Movable load-bearing plates are respectively provided on the upper surface of the two guardrails. Roller slider components that can lift the movable load-bearing plates are respectively provided on the side of the guardrails closest to the mounting plate. Lifting screw components that can drive the roller slider components to move are provided on the top of the two screw mounting seats on the side close to each other. Telescopic screw components that can drive the two guardrails to extend and retract are provided on the bottom of the side close to each other.

[0006] The mounting plate has two load-bearing plate grooves symmetrically arranged on both sides of its upper surface. Two waist-shaped grooves are symmetrically arranged at both ends of the inner side of the two load-bearing plate grooves. Pulley grooves are symmetrically arranged on the side of the load-bearing plate grooves that are far apart from each other.

[0007] The lower surface of the fixed load-bearing plate is fixedly connected to the mounting plate.

[0008] The guardrail includes a side rail, with two side rail guide rods symmetrically fixedly connected to both ends of the side rail. Two slider guide rods are symmetrically arranged on one side of the two side rail guide rods, with one end of the side rail guide rods horizontally slidingly connected to the mounting plate. One end of the two slider guide rods is fixedly connected to the side rail, and the other end of the slider guide rods is horizontally slidingly connected to the mounting plate.

[0009] The movable load-bearing plate includes a movable plate. Multiple lifting guide rods are symmetrically fixed to both ends of the lower surface of the movable plate. A roller inclined surface is provided on the lower surface of the movable plate near the mounting plate. The movable plate is slidably connected to the mounting plate inside the load-bearing plate slide groove. The movable plate is slidably connected to two waist-shaped grooves through two lifting guide rods on one side. The movable plate is vertically slidably connected to the side rail through two lifting guide rods on the other side.

[0010] The roller slider component includes a slider, and multiple rollers are rotatably connected to the top of the slider at even intervals. The slider is horizontally slidably connected to two slider guide rods inside the roller groove. The tops of the multiple rollers are in contact with the lower surface of the movable plate and the roller inclined surface.

[0011] The tops of the two lead screw mounting seats are respectively fixedly connected to both ends of the lower surface of the mounting plate.

[0012] The lifting screw assembly includes a lifting positive and negative screw, with two lifting screw blocks symmetrically threaded at both ends. One end of the lifting screw passes through a screw mounting base and is fixedly connected to a lifting handwheel. Both ends of the lifting screw are rotatably connected to the two screw mounting bases respectively. Two push rods are symmetrically rotatably connected to both sides of the two lifting screw blocks. The other ends of the two push rods on the same side of the two lifting screw blocks are rotatably connected to both ends of the bottom of the slider respectively.

[0013] The telescopic screw component includes a telescopic forward and reverse screw, with two telescopic threaded blocks symmetrically threaded at both ends of the telescopic forward and reverse screw. One end of the telescopic forward and reverse screw passes through a screw mounting base and is fixedly connected to a telescopic handwheel. Both ends of the telescopic forward and reverse screw are rotatably connected to the two screw mounting bases respectively. Two pull rods are symmetrically rotatably connected to both sides of the two telescopic threaded blocks. The other ends of the two pull rods on the same side of the two telescopic threaded blocks are rotatably connected to both ends of the bottom of the side rail respectively.

[0014] The mounting plate has multiple pulley components symmetrically arranged on both sides of its lower surface. Each pulley component includes multiple pulley mounting seats, and pulleys are rotatably connected to the bottom of each pulley mounting seat. The top of each pulley mounting seat is fixedly connected to the lower surface of the mounting plate.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention rotates the telescopic handwheel, which drives the telescopic forward and reverse screws to rotate, thereby moving the two telescopic threaded blocks at both ends. The two telescopic threaded blocks drive multiple pull rods on both sides, pushing the two side rails out along the mounting plate through multiple side rail guide rods and multiple slider guide rods. This, in turn, causes the two movable load-bearing plates to extend out of the mounting plate, which facilitates the support of larger structural components and ensures the stability of the structural components during transportation.

[0016] 2. This invention rotates the lifting handwheel, which drives the lifting screws to rotate, thereby moving the two lifting threaded blocks at both ends. The two lifting threaded blocks drive multiple lifting rods on both sides, pushing the two sliders out along multiple slider guide rods. This, in turn, drives multiple rollers to roll along the roller slopes and move to the lower surface of the movable plate. The movable plate is then lifted along multiple lifting guide rods to the same horizontal plane as the mounting plate, ensuring the flatness of the fixed load-bearing plate and the two movable load-bearing plates, and better supporting the structural components. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the bottom structure of the present invention; Figure 3 This is a schematic diagram of the mounting plate structure of the present invention; Figure 4 This is a schematic diagram of the installation structure of the protective fence according to the present invention; Figure 5 This is a schematic diagram of the movable load-bearing plate structure of the present invention; Figure 6 This is a schematic diagram of the roller slider component mounting structure of the present invention; Figure 7 This is a schematic diagram of the mounting structure of the lead screw component of the present invention; Figure 8 This is a schematic diagram of the pulley component mounting structure of the present invention; Reference numerals: 1. Mounting plate; 101. Load-bearing plate groove; 102. Waist-shaped groove; 103. Pulley groove; 2. Fixed load-bearing plate; 3. Guardrail; 301. Side rail; 302. Side rail guide rod; 303. Sliding guide rod; 4. Screw mounting base; 5. Movable load-bearing plate; 501. Movable plate; 502. Lifting guide rod; 503. Roller inclined surface; 6. Roller slider assembly; 601. Sliding block; 602. Roller; 7. Lifting screw assembly; 701. Lifting forward and reverse screws; 702. Lifting threaded block; 703. Lifting handwheel; 704. Top rod; 8. Telescopic screw assembly; 801. Telescopic forward and reverse screws; 802. Telescopic threaded block; 803. Telescopic handwheel; 804. Pull rod; 9. Pulley assembly; 901. Pulley mounting base; 902. Pulley. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: Please see Figures 1-4 , Figure 8 The present invention provides a technical solution: a driven railcar, including a mounting plate 1, a fixed load-bearing plate 2 on the upper surface of the mounting plate 1, two guardrails 3 symmetrically arranged on both sides of the mounting plate 1, two screw mounting seats 4 symmetrically arranged at both ends of the lower surface of the mounting plate 1, movable load-bearing plates 5 respectively arranged on the upper surface of the two guardrails 3, roller slider components 6 that can lift the movable load-bearing plates 5 respectively arranged on the side of the guardrails 3 near the mounting plate 1, lifting screw components 7 that can drive the roller slider components 6 to move are arranged on the top of the side of the two screw mounting seats 4 close to each other, and telescopic screw components 8 that can drive the two guardrails 3 to extend and retract are arranged on the bottom of the side of the screw mounting seats 4 close to each other.

[0020] The mounting plate 1 has two load-bearing plate grooves 101 symmetrically arranged on both sides of its upper surface. The two load-bearing plate grooves 101 have two waist-shaped grooves 102 symmetrically arranged at both ends of their inner sides. The load-bearing plate grooves 101 have pulley grooves 103 symmetrically arranged on the opposite side of each other. By setting two load-bearing plate grooves 101, the two movable load-bearing plates 5 can be retracted into the two load-bearing plate grooves 101, which can be extended or retracted according to different needs, saving space.

[0021] The lower surface of the fixed load-bearing plate 2 is fixedly connected to the mounting plate 1.

[0022] The guardrail 3 includes a side rail 301. Two side rail guide rods 302 are symmetrically fixedly connected to both ends of the side rail 301. Two sliding guide rods 303 are symmetrically arranged on one side of the two side rail guide rods 302. One end of the side rail guide rod 302 is horizontally slidably connected to the mounting plate 1. One end of the two sliding guide rods 303 is fixedly connected to the side rail 301, and the other end of the sliding guide rods 303 is horizontally slidably connected to the mounting plate 1. By setting two side rail guide rods 302, the side rail 301 can extend more smoothly.

[0023] The movable load-bearing plate 5 includes a movable plate 501. Multiple lifting guide rods 502 are symmetrically fixed to both ends of the lower surface of the movable plate 501. A roller inclined surface 503 is provided on the lower surface of the movable plate 501 near the mounting plate 1. The movable plate 501 is slidably connected to the mounting plate 1 inside the load-bearing plate slide groove 101. The movable plate 501 is slidably connected to two waist-shaped grooves 102 through two lifting guide rods 502 on one side. The movable plate 501 is vertically slidably connected to the side rail 301 through two lifting guide rods 502 on the other side. By setting multiple lifting guide rods 502, the movable load-bearing plate 5 can extend and retract more smoothly.

[0024] The tops of the two screw mounting seats 4 are fixedly connected to the two ends of the lower surface of the mounting plate 1, respectively. By setting the two screw mounting seats 4, it is easy to install the telescopic screw component 8, which drives the two guardrails 3 to extend.

[0025] The telescopic screw component 8 includes a telescopic forward and reverse screw 801. Two telescopic threaded blocks 802 are symmetrically threaded at both ends of the telescopic forward and reverse screw 801. One end of the telescopic forward and reverse screw 801 passes through the screw mounting base 4 and is fixedly connected to a telescopic handwheel 803. The two ends of the telescopic forward and reverse screw 801 are rotatably connected to the two screw mounting bases 4 respectively. Two pull rods 804 are symmetrically rotatably connected to both sides of the two telescopic threaded blocks 802. The other ends of the two pull rods 804 on the same side of the two telescopic threaded blocks 802 are rotatably connected to the bottom ends of the side rail 301 respectively. By setting the telescopic screw component 8, two guardrails 3 can be extended out of the mounting plate at the same time, thereby driving the movable load-bearing plate 5 to extend, increasing the support area, and facilitating the support of larger structural components.

[0026] The mounting plate 1 has multiple pulley components 9 symmetrically arranged on both sides of its lower surface. Each pulley component 9 includes multiple pulley mounting seats 901. The bottom of each pulley mounting seat 901 is rotatably connected to a pulley 902. The top of each pulley mounting seat 901 is fixedly connected to the lower surface of the mounting plate 1. By setting multiple pulley components 9, they can cooperate with the track to drive the mounting plate 1 to move, thereby driving the structural components above the fixed load-bearing plate 2 to move and transport them.

[0027] Working principle: Rotating the telescopic handwheel 803 drives the telescopic forward and reverse screws 801 to rotate on the two screw mounting seats 4, which in turn drives the two telescopic threaded blocks 802 at both ends to move. This causes the two telescopic threaded blocks 802 to drive the multiple pull rods 804 on both sides to push the two side rails 301. The two side rails 301 are pushed out along the mounting plate 1 through the multiple side rail guide rods 302 and the multiple slider guide rods 303. This causes the two movable load-bearing plates 5 to extend out of the mounting plate 1 through the two lifting guide rods 502 along the two waist-shaped grooves 102 and the load-bearing plate sliding grooves 101, thereby expanding the support surface and supporting larger structural components.

[0028] Example 2: Please see Figures 5-7 The present invention provides a technical solution: a driven railcar, including a mounting plate 1, a fixed load-bearing plate 2 on the upper surface of the mounting plate 1, two guardrails 3 symmetrically arranged on both sides of the mounting plate 1, two screw mounting seats 4 symmetrically arranged at both ends of the lower surface of the mounting plate 1, movable load-bearing plates 5 respectively arranged on the upper surface of the two guardrails 3, roller slider components 6 that can lift the movable load-bearing plates 5 respectively arranged on the side of the guardrails 3 near the mounting plate 1, lifting screw components 7 that can drive the roller slider components 6 to move are arranged on the top of the side of the two screw mounting seats 4 close to each other, and telescopic screw components 8 that can drive the two guardrails 3 to extend and retract are arranged on the bottom of the side of the screw mounting seats 4 close to each other.

[0029] The mounting plate 1 has two load-bearing plate grooves 101 symmetrically arranged on both sides of its upper surface. The two load-bearing plate grooves 101 have two waist-shaped grooves 102 symmetrically arranged at both ends of their inner sides. The load-bearing plate grooves 101 have pulley grooves 103 symmetrically arranged on the opposite side. By setting the pulley grooves 103, the roller slider component 6 can be retracted, avoiding affecting the fit between the guardrail 3 and the mounting plate 1 and ensuring the flatness of the device.

[0030] The guardrail 3 includes a side rail 301. Two side rail guide rods 302 are symmetrically fixedly connected to both ends of the side rail 301. Two slider guide rods 303 are symmetrically arranged on one side of the two side rail guide rods 302. One end of the side rail guide rod 302 is horizontally slidably connected to the mounting plate 1. One end of the two slider guide rods 303 is fixedly connected to the side rail 301. The other end of the slider guide rods 303 is horizontally slidably connected to the mounting plate 1. By setting two slider guide rods 303, the roller slider component 6 can slide more smoothly, thereby more smoothly lifting the movable load-bearing plate 5.

[0031] The movable load-bearing plate 5 includes a movable plate 501. Multiple lifting guide rods 502 are symmetrically fixed to both ends of the lower surface of the movable plate 501. A roller inclined surface 503 is provided on the lower surface of the movable plate 501 near the mounting plate 1. The movable plate 501 is slidably connected to the mounting plate 1 inside the load-bearing plate slide groove 101. The movable plate 501 is slidably connected to two waist-shaped grooves 102 through two lifting guide rods 502 on one side. The movable plate 501 is vertically slidably connected to the side rail 301 through two lifting guide rods 502 on the other side. By setting the roller inclined surface 503, the roller slider component 6 can more easily lift the movable load-bearing plate 5 along the roller inclined surface 503.

[0032] The roller slider component 6 includes a slider 601, with multiple rollers 602 evenly spaced and rotatably connected to the top of the slider 601. The slider 601 is horizontally slidably connected to two slider guide rods 303 inside the pulley groove 103. The tops of the multiple rollers 602 are in contact with the lower surface of the movable plate 501 and the roller inclined surface 503. By setting multiple rollers 602, they can roll with the lower surface of the movable load-bearing plate 5, reducing friction and making it easier to lift the movable load-bearing plate 5.

[0033] The tops of the two lead screw mounting seats 4 are fixedly connected to the two ends of the lower surface of the mounting plate 1, respectively.

[0034] The lifting screw component 7 includes a lifting positive and negative screw 701. Two lifting screw blocks 702 are symmetrically threaded at both ends of the lifting positive and negative screw 701. One end of the lifting positive and negative screw 701 passes through the screw mounting seat 4 and is fixedly connected to a lifting handwheel 703. The two ends of the lifting positive and negative screw 701 are rotatably connected to the two screw mounting seats 4 respectively. Two push rods 704 are symmetrically rotatably connected to both sides of the two lifting screw blocks 702. The other ends of the two push rods 704 on the same side of the two lifting screw blocks 702 are rotatably connected to the bottom ends of the slider 601 respectively. By setting the lifting screw component 7, the two roller slider components 6 can be driven to slide out along the slider guide rod 303 at the same time, thereby lifting the movable load-bearing plate 5.

[0035] Working principle: Rotating the lifting handwheel 703 drives the lifting positive and negative lead screws 701 to rotate on the two lead screw mounting seats 4, which in turn drives the two lifting threaded blocks 702 at both ends to move. This causes the two lifting threaded blocks 702 to drive the multiple push rods 704 on both sides to push the two sliders 601, pushing the two sliders 601 out along the multiple slider guide rods 303. This, in turn, drives the multiple rollers 602 to roll along the roller inclined surface 503, moving them to the lower surface of the movable plate 501. This causes the movable plate 501 to rise along the multiple lifting guide rods 502 to the same horizontal plane as the mounting plate 1, ensuring the flatness of the fixed load-bearing plate 2 and the two movable load-bearing plates 5, and better supporting the structural components.

[0036] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A driven trolley comprising a mounting plate (1), characterised in that: The upper surface of the mounting plate (1) is provided with a fixed bearing plate (2), two guardrails (3) are symmetrically arranged on both sides of the mounting plate (1), two lead screw mounting seats (4) are symmetrically arranged at the ends of the lower surface of the mounting plate (1), the upper surfaces of the two guardrails (3) are respectively provided with movable bearing plates (5), the guardrails (3) are respectively provided with roller sliding block components (6) capable of lifting the movable bearing plates (5) near the side of the mounting plate (1), the mutually close sides of the two lead screw mounting seats (4) are provided with lifting lead screw components (7) capable of moving the roller sliding block components (6), and the mutually close bottom sides of the lead screw mounting seats (4) are provided with telescopic lead screw components (8) capable of telescoping the two guardrails (3).

2. A driven railcar as defined in claim 1, characterized in that: The upper surface of the mounting plate (1) is provided with two bearing plate sliding grooves (101) symmetrically arranged on both sides, and two waist-shaped grooves (102) are symmetrically arranged at the two ends of the inner sides of the two bearing plate sliding grooves (101), and the mutually far sides of the bearing plate sliding grooves (101) are respectively provided with pulley grooves (103) symmetrically arranged.

3. A driven railcar as defined in claim 2, characterized in that: The lower surface of the fixed bearing plate (2) is fixedly connected with the mounting plate (1).

4. The driven railcar of claim 2, wherein: The guardrail (3) comprises a side rail (301), two side rail guide rods (302) are fixedly connected to the two ends of the side rail (301) symmetrically, two sliding block guide rods (303) are symmetrically arranged on the mutually close side of the two side rail guide rods (302), one end of the side rail guide rod (302) is horizontally slidably connected with the mounting plate (1), one end of the two sliding block guide rods (303) is fixedly connected with the side rail (301), and the other end of the sliding block guide rod (303) is horizontally slidably connected with the mounting plate (1).

5. A driven railcar as defined in claim 4, wherein: The movable bearing plate (5) comprises a movable plate (501), a plurality of lifting guide rods (502) are fixedly connected to the two ends of the lower surface of the movable plate (501) symmetrically, a roller inclined surface (503) is arranged on the side of the lower surface of the movable plate (501) close to the mounting plate (1), the movable plate (501) is slidably connected with the mounting plate (1) on the inner side of the bearing plate sliding groove (101), the movable plate (501) is slidably connected with the two waist-shaped grooves (102) through the two lifting guide rods (502) on one side, and the movable plate (501) is perpendicularly slidably connected with the side rail (301) through the two lifting guide rods (502) on the other side.

6. A driven railcar as defined in claim 5, wherein: The roller sliding block component (6) comprises a sliding block (601), a plurality of rollers (602) are uniformly and intermittently rotatably connected to the top of the sliding block (601), the sliding block (601) is horizontally slidably connected with the two sliding block guide rods (303) on the inner side of the pulley groove (103), and the tops of the plurality of rollers (602) are attached to the lower surface of the movable plate (501) and the roller inclined surface (503).

7. A driven railcar as defined in claim 6, characterized in that: The top of each of the two lead screw mounting seats (4) is fixedly connected with the end of the lower surface of the mounting plate (1).

8. A driven railcar as defined in claim 7, characterized in that: The jacking screw part (7) includes a jacking lead screw (701), two jacking threaded blocks (702) are symmetrically connected at both ends of the jacking lead screw (701), a jacking hand wheel (703) is fixedly connected to one end of the jacking lead screw (701) through a screw mounting seat (4), both ends of the jacking lead screw (701) are rotatably connected with two screw mounting seats (4), two jacks (704) are rotatably connected to both sides of the two jacking threaded blocks (702), respectively, and the other ends of the two jacks (704) on the same side of the two jacking threaded blocks (702) are rotatably connected with both ends of the bottom of a sliding block (601).

9. A driven railcar as defined in claim 7, wherein: The telescopic screw part (8) includes a telescopic lead screw (801), two telescopic threaded blocks (802) are symmetrically connected at both ends of the telescopic lead screw (801), a telescopic hand wheel (803) is fixedly connected to one end of the telescopic lead screw (801) through a screw mounting seat (4), both ends of the telescopic lead screw (801) are rotatably connected with two screw mounting seats (4), two pull rods (804) are rotatably connected to both sides of the two telescopic threaded blocks (802), respectively, and the other ends of the two pull rods (804) on the same side of the two telescopic threaded blocks (802) are rotatably connected with both ends of the bottom of a side post (301).

10. The driven railcar of claim 1, wherein: A plurality of pulley parts (9) are symmetrically arranged on both sides of both ends of the lower surface of the mounting plate (1), the plurality of pulley parts (9) include a plurality of pulley mounting seats (901), pulleys (902) are rotatably connected to the bottoms of the plurality of pulley mounting seats (901), and the tops of the pulley mounting seats (901) are fixedly connected with the lower surface of the mounting plate (1).