CN112047017A

CN112047017A - Chain bucket type elevator

Info

Publication number: CN112047017A
Application number: CN202011044221.0A
Authority: CN
Inventors: 汪忠诚; 王朝鹏
Original assignee: Individual
Current assignee: Yumen Xinjieyuan Mud Material Co ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2020-12-08
Anticipated expiration: 2040-09-28
Also published as: CN112047017B

Abstract

The invention discloses a chain bucket type elevator, which comprises a limiting device and an adjusting device, wherein the limiting device comprises a first lifting device and a second lifting device; stop device includes chain, sprocket, baffle, the sprocket is located the internal surface of chain and meshes with the chain mutually, the baffle is located the both sides of chain, and its and chain sliding connection, the surface fixed mounting of chain has the hopper, the equal fixedly connected with slide bar in both sides surface of hopper, the baffle is close to one side surface of hopper and has seted up the spout, slide bar and spout sliding connection, the outer disc fixed mounting of sprocket has the teeth of a cogwheel, the rear end surface of the teeth of a cogwheel is seted up flutedly, the both sides internal surface of chain rotates and is connected with the round pin axle, the outer disc fixedly connected with rectangular block of round pin axle. The chain adjusting device ensures the stability of the hoister in the operation process, reduces the probability that the chain is separated from the transmission gear, and can quickly adjust the chain of the hoister to enable the chain to be in a tensioning state all the time.

Description

Chain bucket type elevator

Technical Field

The invention relates to the technical field of material transportation, in particular to a chain bucket type elevator.

Background

As efficient vertical lifting equipment, the chain bucket type lifter is widely applied to the conveying work of materials such as mineral aggregate, cement clinker, gypsum and the like.

In the process of implementing the invention, the inventor finds that at least the following problems in the prior art are not solved: 1. when the bucket chain elevator transports stones, the chain is often separated from the chain wheel, so that the mechanical emergency stop is caused, the normal operation of production is influenced, the deviation of the chain in the operation can increase the friction between the chain wheel and the chain, so that the chain wheel and the chain are both abraded, the operation stability of the chain is reduced, and if the hopper is filled with materials in the operation of the chain, the recovery is difficult, so that the transportation efficiency is reduced; 2. after the chain is used for a long time, the connection of the rotating shaft on the chain is loosened at the worn position, and the chain is bent by pressing the chain when the bucket is filled with materials, so that the transportation stability is reduced, and the difficulty in the transportation process is increased; 3. present can adopt the transportation area to transport when carrying out the transportation of lifting means to the stone, the slope in transportation area needs lessly, long-time transportation stone, the phenomenon of lax can appear in the chain, the shake can take place when the chain moves, reduce the stability of lifting machine transportation, and current hopper opening does not improve to the stone, the opening of traditional hopper is less, when the shipment stone, need adjust the angle that the stone got into the hopper, comparatively waste time, and the hopper can vibrate when transporting the stone, and lead to the fact the scratch to the hopper itself.

For this purpose, a bucket elevator is proposed.

Disclosure of Invention

The invention aims to provide a chain bucket type elevator, which can ensure the stability of the elevator in the operation process, reduce the probability of the chain being separated from a transmission gear, and quickly adjust the chain of the elevator to enable the chain to be always in a tensioning state in the operation process of the elevator, so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a chain bucket type elevator comprises a limiting device and an adjusting device; the limiting device comprises a chain, a chain wheel and a baffle plate, wherein the chain wheel is positioned on the inner surface of the chain and meshed with the chain, the baffle plate is positioned on two sides of the chain and is in sliding connection with the chain, a hopper is fixedly arranged on the outer surface of the chain, slide rods are fixedly connected to the outer surfaces of the two sides of the hopper, a chute is formed in the outer surface of one side, close to the hopper, of the baffle plate, the slide rods are in sliding connection with the chute, gear teeth are fixedly arranged on the outer circular surface of the chain wheel, grooves are formed in the outer surface of the rear end of the gear teeth, pin shafts are rotatably connected to the inner surfaces of;

adjusting device includes bracing piece, horizontal pole and bracing piece sliding connection, the rectangular channel has been seted up to one side surface of bracing piece, the horizontal pole slides from top to bottom at the internal surface of rectangular channel, the horizontal pole is located the outer disc below fixedly connected with telescopic link of rectangular channel, the surface sliding connection of telescopic link has the spring, spring and horizontal pole fixed connection, and the junction of the outer disc of horizontal pole and chain rotates and is connected with the regulating wheel.

Preferably, the equal fixedly connected with rubber ring in the position that the excircle face of round pin axle is close to both sides, the inside of round pin axle corresponds with the rubber ring the equal fixed connection of position and spring and telescopic link, and rubber ring and the equal fixed connection of spring and telescopic link, the rubber ring is the arc structure, two the rubber ring is the symmetry and sets up the arc opening and correspond each other.

When the chain is about to break away from the sprocket in the process of chain operation, the sprocket extrudees the curved rubber ring on the round pin axle, drives the rubber ring and presses the spring that moves to be located round pin axle inside and move down with the telescopic link, and makes the teeth of a cogwheel of sprocket fall into the middle surface of round pin axle again under the effect of arc rubber ring.

Preferably, the chain includes outer link joint and inner link joint, and inner link joint and outer link joint are the interval setting, one side surface of inner link joint rotates and is connected with the regulation pole, two the equal fixedly connected with rack of one side surface that the outer link joint is adjacent, and the flank of tooth of two adjacent racks is relative, and adjusts the pole and mesh mutually with the rack, adjust the one end fixedly connected with fixed block of pole excircle face, the fixed slot has been seted up with the junction of fixed block to the inner link joint.

When the loose chain is adjusted, the adjusting rod on the inner chain plate is rotated to drive the racks on the outer chain plate to move, so that the two racks drive the outer chain plate to be close to the inner chain plate, the chain is fastened, after the movement is completed, the adjusting rod is pushed to drive the fixing block on the adjusting rod to enter the fixing groove on the inner surface of the chain, the adjusting rod is not rotated, the chain is fastened, the adjustment is convenient, and the working efficiency is improved.

Preferably, the number of the rectangular blocks is a plurality of, the rectangular blocks are annularly distributed on the outer surface of the pin shaft, the rectangular blocks are made of hard rubber, and anti-skid grains are arranged on the outer surface of the rectangular blocks.

When the chain wheel rotates, the grooves in the wheel teeth are in sliding connection with the rectangular blocks on the outer surface of the pin shaft on the chain, the probability that the chain and the hopper deviate towards two sides in the transportation process is reduced under the action of the sliding rods and the rectangular blocks, and the running stability of the chain is improved.

Preferably, the quantity of hopper is a plurality of, and its all with outer link joint fixed connection on the chain, every the internal surface both sides of hopper all are provided with anti-skidding line, and the equal fixedly connected with rubber pad in its bottom.

When being favorable to the hopper to transport great object, the rubber pad avoids the object to cause the damage to the hopper, and the anti-skidding line can increase the frictional force of object and hopper, guarantees the stability of transportation.

Preferably, the inner chain plate is connected with the adjusting rod in a sliding mode, the number of the adjusting rods on the single inner chain plate is two, the adjusting rods are located on two sides of the inner chain plate respectively, the fixing block on the rack is connected with the fixing groove in a sliding mode, and anti-skidding threads are arranged on the outer surface of the fixing block and the inner surface of the fixing groove.

When the chain is loosened, the adjusting rod on the chain is rotated to drive the racks on the chain to move, so that the two racks move to drive the connecting points on the chain to fasten, after the chain is moved, the adjusting rod is pushed to drive the fixing block on the adjusting rod to enter the fixing groove on the inner surface of the chain, the fixing bolt cannot rotate, the chain is fastened, and the anti-slip threads ensure the stability of the adjusting rod in the fixing groove.

Compared with the prior art, the invention has the beneficial effects that:

1. the chain bucket elevator is started, the chain wheel rotates to drive the chain to rotate, the chain drives the hopper fixedly connected with the chain to move, materials are transported, the hopper moves to drive the sliding rod to move in the sliding groove on the baffle plate, the stability of the hopper in the ascending process is improved, the risk that the hopper shakes to drive the chain to shake and increase the chain to be separated from the chain wheel is avoided, the hopper opening is set to be square, the design of a large opening with a small inner part and a large outer part is adopted, stones can be quickly loaded into the hopper, the working efficiency is improved, the rubber pad fixed in the hopper and the anti-skid patterns on the two sides are avoided, the damage to the hopper caused by the transported stones is avoided, the anti-skid patterns can increase the friction force between an object and the hopper, the transportation stability is ensured, when the chain wheel rotates, the grooves on the wheel teeth are in sliding connection with the rectangular blocks on the outer surface of the pin shaft on the chain, the stability of chain operation has been improved, at the in-process of chain operation, if the chain takes place the skew, the epaxial teeth of a cogwheel of sprocket is close to the chain and the rubber ring contact of round pin axle one side, when the skew degree increase, the teeth of a cogwheel extrudees the rubber ring, the rubber ring receives to begin to push down the inside spring of round pin axle and telescopic link after the oppression, rubber ring pushes down back height reduction, and the radian on rubber ring surface makes the epaxial teeth of a cogwheel of sprocket begin to slide, to the teeth of a cogwheel resume normal position again can, and the rubber ring resumes under the effect of spring, the danger that the sprocket breaks away from the chain has been avoided, the stability of chain bucket elevator operation.

2. The chain can appear lax phenomenon because of wearing and tearing after using a period, can lead to the chain can not stably stimulate the hopper, and increased the risk that the chain breaks away from the sprocket, this moment when the chain rotates the below of lifting machine, gliding horizontal pole in the rectangular channel on the bracing piece, the starting movement under the effect of spring, the pulling is located regulating wheel and chain meshing on the horizontal pole, guarantee that the chain is in the state of tightening, make the chain reduce the chain at the in-process of pulling the hopper and rock, reduce the risk that the chain breaks away from the sprocket, avoid leading to breaking down in the transportation because of the lax of chain.

3. Chain bucket elevator is when transporting heavier stone, long-time use can make the inseparable degree of being connected between the inner plate on the chain and the outer link joint can reduce, need in time to adjust the risk of avoiding appearing the chain derailment, when adjusting lax chain, rotate the regulation pole that is located on the inner plate, drive the rack removal on the outer link joint, make two racks drive the outer link joint and be close to each other with the inner plate, make the chain obtain the fastening, remove and accomplish the back, promote to adjust the pole and drive the fixed block that is located on adjusting the pole and enter into the fixed slot of chain internal surface, it can not rotate to make the regulation pole, make the chain fastening, and it is convenient to adjust, and work efficiency is improved.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a structural view of the pin of the present invention;

FIG. 3 is a structural view of the sprocket of the present invention;

FIG. 4 is a view of the adjustment lever of the present invention in combination with a rack;

FIG. 5 is a view of the combination of the fixing groove and the chain of the present invention;

fig. 6 is a view of the chain in combination with the hopper of the present invention.

In the figure: 1. a chain; 2. a hopper; 3. a baffle plate; 4. a chute; 5. a slide bar; 6. a support bar; 7. a rectangular groove; 8. a spring; 9. a sprocket; 10. an adjustment wheel; 11. a cross bar; 12. a pin shaft; 13. a rack; 14. adjusting a rod; 15. fixing grooves; 16. a fixed block; 17. a groove; 18. a rectangular block; 19. gear teeth; 20. a rubber ring; 21. an outer link plate; 22. an inner link plate; 23. a telescopic rod.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 6, the present invention provides a technical solution:

a chain bucket type elevator comprises a limiting device and an adjusting device; the limiting device comprises a chain 1, a chain wheel 9 and a baffle plate 3, wherein the chain wheel 9 is positioned on the inner surface of the chain 1 and is meshed with the chain 1, the baffle plate 3 is positioned on two sides of the chain 1 and is in sliding connection with the chain 1, a hopper 2 is fixedly arranged on the outer surface of the chain 1, slide bars 5 are fixedly connected to the outer surfaces of two sides of the hopper 2, a chute 4 is formed in the outer surface of one side, close to the hopper 2, of the baffle plate 3, the slide bars 5 are in sliding connection with the chute 4, gear teeth 19 are fixedly arranged on the outer circular surface of the chain wheel 9, a groove 17 is formed in the outer surface of the rear end of the gear teeth 19, pin shafts 12 are rotatably connected to the inner surfaces of two sides;

adjusting device includes bracing piece 6,

horizontal pole

11 and 6 sliding connection of bracing piece, rectangular channel 7 has been seted up to one side surface of bracing piece 6, horizontal pole 11 slides from top to bottom at the internal surface of rectangular channel 7, horizontal pole 11 is located the outer disc below fixedly connected with telescopic link 23 of rectangular channel 7, the surface sliding connection of telescopic link 23 has spring 8,

spring

8 and 11 fixed connection of horizontal pole, and the junction of the outer disc of horizontal pole 11 and chain 1 rotates and is connected with regulating wheel 10.

The chain bucket elevator is started, the chain wheel 9 rotates to drive the chain 1 to rotate, the chain 1 drives the hopper 2 fixedly connected with the chain 1 to move, materials are transported, the hopper 2 moves to drive the sliding rod 5 to move in the sliding groove 4 on the baffle plate 3, the stability of the hopper 2 in the process of ascending is improved, the risk that the hopper 2 shakes to drive the chain 1 to shake to increase the chain 1 to be separated from the chain wheel 9 is avoided, the opening of the hopper is set to be square, the design of a large opening with a small inner part and a large outer part is adopted, stones can be quickly loaded into the hopper, the working efficiency is improved, the conveying stones are prevented from being damaged by the conveyed stones, the friction force between objects and the hopper can be increased by the anti-slip lines, the transportation stability is ensured, and when the chain wheel 9 rotates, the grooves 17 on the wheel teeth 19 are in sliding connection with the rectangular blocks 18 on the, the probability that the chain 1 and the hopper 2 deviate to two sides in the transportation process is reduced under the action of the sliding rod 5 and the rectangular block 18, the running stability of the chain 1 is improved, the chain 1 can loose due to abrasion after being used for a period of time, the hopper 2 cannot be stably pulled by the chain 1, the risk that the chain 1 is separated from the chain wheel 9 is increased, the chain 1 rotates to the lower part of a lifting machine at the moment, the cross rod 11 slides in the rectangular groove 7 on the supporting rod 6 and starts to move under the action of the spring 8, the adjusting wheel 10 positioned on the cross rod 11 is meshed with the chain 1 by pulling, the chain 1 is ensured to be in a tightening state, the chain 1 is enabled to shake in the process of pulling the hopper 2, the risk that the chain 1 is separated from the chain wheel 9 is reduced, and the failure in the transportation process caused by the loosening of the chain 1 is avoided.

As an embodiment of the present invention, the positions of the outer circumferential surface of the pin 12 near both sides are fixedly connected with rubber rings 20, the positions of the inside of the pin 12 corresponding to the rubber rings 20 are fixedly connected with the springs 8 and the telescopic rods 23, the rubber rings 20 are in an arc structure, and the two rubber rings 20 are symmetrically provided with arc openings and correspond to each other; in the in-process of chain 1 operation, if chain 1 takes place the skew, the teeth of a cogwheel 19 on the sprocket 9 is close to chain 1 and the contact of the rubber ring 20 of round pin axle 12 one side, when the skew degree increase, the teeth of a cogwheel 19 extrudes rubber ring 20, rubber ring 20 receives and begins to push down the inside spring 8 of round pin axle 12 and telescopic link 23 after oppressing, the back height reduction is pushed down to rubber ring 20, and the radian on rubber ring 20 surface makes the teeth of a cogwheel 19 on the sprocket 9 begin to slide, to the teeth of a cogwheel 19 resume the normal position again can, and rubber ring 20 resumes under the effect of spring 8, the danger that sprocket 9 breaks away from chain 1 has been avoided, the stability of chain bucket elevator operation has been guaranteed.

As an embodiment of the invention, the chain 1 comprises outer chain plates 21 and inner chain plates 22, the inner chain plates 22 and the outer chain plates 21 are arranged at intervals, an adjusting rod 14 is rotatably connected to the outer surface of one side of each of the inner chain plates 22, racks 13 are fixedly connected to the outer surfaces of adjacent sides of the two outer chain plates 21, the tooth surfaces of the two adjacent racks 13 are opposite, the adjusting rod 14 is meshed with the racks 13, a fixing block 16 is fixedly connected to one end of the outer circular surface of the adjusting rod 14, and a fixing groove 15 is formed at the connection position of the inner chain plates 22 and the fixing block 16; chain bucket elevator is when transporting heavier stone, long-time use can make the inseparable degree of being connected between inner plate 22 and the outer plate 21 on the chain 1 can reduce, need in time to adjust the risk of avoiding appearing chain 1 derailment, when adjusting lax chain 1, the rotation is located the regulation pole 14 on inner plate 22, drive the rack 13 on the outer plate 21 and remove, make two racks 13 drive outer plate 21 and inner plate 22 and be close to each other, make chain 1 obtain the fastening, remove and accomplish the back, promote to adjust pole 14 and drive and be located the fixed block 16 on adjusting pole 14 and enter into the fixed slot 15 of 1 internal surface of chain, make and adjust pole 14 unrotatable, make chain 1 fastening, and it is convenient to adjust, and the work efficiency is improved.

The working principle is as follows: starting a chain bucket elevator, wherein a chain wheel 9 rotates to drive a chain 1 to rotate, the chain 1 drives a hopper 2 fixedly connected with the chain 1 to move, materials are transported, the hopper 2 moves to drive a sliding rod 5 to move in a sliding groove 4 on a baffle plate 3, so that the stability of the hopper 2 in the process of rising is improved, the risk that the hopper 2 shakes to drive the chain 1 to shake to increase the chain 1 to be separated from the chain wheel 9 is avoided, when the chain wheel 9 rotates, a groove 17 on a gear tooth 19 is in sliding connection with a rectangular block 18 on the outer surface of a pin shaft 12 on the chain 1, the probability that the chain 1 and the hopper 2 shift towards two sides in the process of transportation is reduced under the action of the sliding rod 5 and the rectangular block 18, the running stability of the chain 1 is improved, if the chain 1 shifts, the gear tooth 19 on the chain wheel 9 is close to the chain 1 and contacts with a, when the deviation degree is increased, the gear teeth 19 extrude the rubber ring 20, the rubber ring 20 is pressed to press down the spring 8 and the telescopic rod 23 in the pin shaft 12, the height of the rubber ring 20 is reduced after the rubber ring 20 is pressed down, the radian of the surface of the rubber ring 20 enables the gear teeth 19 on the chain wheel 9 to slide until the gear teeth 19 restore to the original position, the rubber ring 20 restores to the original position under the action of the spring 8, the danger that the chain wheel 9 is separated from the chain 1 is avoided, the operation stability of the bucket elevator is ensured, the phenomenon that the chain 1 loosens due to abrasion after being used for a period of time can cause the chain 1 not to stably pull the hopper 2, the risk that the chain 1 is separated from the chain wheel 9 is increased, at the moment, when the chain 1 rotates to the lower part of the elevator, the cross rod 11 sliding in the rectangular groove 7 on the supporting rod 6 starts to move under the action of the spring 8, the adjusting wheel 10 positioned on the cross rod, the chain 1 is ensured to be in a tightened state, the chain 1 is enabled to reduce the shaking of the chain 1 in the process of pulling the hopper 2, the risk that the chain 1 is separated from the chain wheel 9 is reduced, the problem that the chain 1 breaks down in the transportation process due to the loosening of the chain 1 is avoided, when a bucket elevator transports heavier stones, the tightness degree of connection between the inner chain plate 22 and the outer chain plate 21 on the chain 1 can be reduced due to long-time use, the risk that the chain 1 is derailed needs to be timely adjusted, when the loosened chain 1 is adjusted, the adjusting rod 14 on the inner chain plate 22 is rotated to drive the rack 13 on the outer chain plate 21 to move, the two racks 13 drive the outer chain plate 21 and the inner chain plate 22 to be close to each other, the chain 1 is fastened, after the movement is completed, the adjusting rod 14 is pushed to drive the fixing block 16 on the adjusting rod 14 to enter, the adjusting rod 14 is not rotatable, the chain 1 is fastened, the adjustment is convenient, and the working efficiency is improved.

The electric elements in the document are electrically connected with an external main controller and 220V mains supply through a transformer, the main controller can be a conventional known device controlled by a computer and the like, the product model provided by the invention is only used according to the structural characteristics of the product, the product can be adjusted and modified after being purchased, so that the product is more matched with and accords with the technical scheme of the invention, the product model is a technical scheme of the optimal application of the technical scheme, the product model can be replaced and modified according to the required technical parameters, and the product model is familiar to the technical personnel in the field, so that the technical scheme provided by the invention can clearly obtain the corresponding use effect.

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

Claims

1. A chain bucket type elevator comprises a limiting device and an adjusting device;

stop device includes chain (1), sprocket (9), baffle (3), the internal surface that sprocket (9) are located chain (1) meshes mutually with chain (1), baffle (3) are located the both sides of chain (1), and its and chain (1) sliding connection, its characterized in that: the chain is characterized in that a hopper (2) is fixedly arranged on the outer surface of the chain (1), sliding rods (5) are fixedly connected to the outer surfaces of two sides of the hopper (2), a sliding groove (4) is formed in the outer surface of one side, close to the hopper (2), of the baffle (3), the sliding rods (5) are in sliding connection with the sliding groove (4), gear teeth (19) are fixedly arranged on the outer circular surface of the chain wheel (9), a groove (17) is formed in the outer surface of the rear end of each gear tooth (19), a pin shaft (12) is rotatably connected to the inner surfaces of two sides of the chain (1), and a rectangular block (18) is fixedly connected to the;

adjusting device includes bracing piece (6), horizontal pole (11) and bracing piece (6) sliding connection, rectangular channel (7) have been seted up to one side surface of bracing piece (6), horizontal pole (11) slide from top to bottom at the internal surface of rectangular channel (7), outer disc below fixedly connected with telescopic link (23) that horizontal pole (11) are located rectangular channel (7), the surface sliding connection of telescopic link (23) has spring (8), spring (8) and horizontal pole (11) fixed connection, and the junction of the outer disc of horizontal pole (11) and chain (1) rotates and is connected with regulating wheel (10).

2. The bucket elevator as claimed in claim 1, wherein: the equal fixedly connected with rubber ring (20) in the position that the excircle face of round pin axle (12) is close to both sides, the inside of round pin axle (12) corresponds with rubber ring (20) position and spring (8) and the equal fixed connection of telescopic link (23), and rubber ring (20) and spring (8) and the equal fixed connection of telescopic link (23), rubber ring (20) are the arc structure, two rubber ring (20) are the symmetry and set up the arc opening and correspond each other.

3. The bucket elevator as claimed in claim 1, wherein: chain (1) includes outer link joint (21) and inner link joint (22), and inner link joint (22) are the interval setting with outer link joint (21), one side surface rotation of inner link joint (22) is connected with adjusts pole (14), two the equal fixedly connected with rack (13) of one side surface that outer link joint (21) is adjacent, and the flank of tooth of two adjacent rack (13) is relative, and adjusts pole (14) and rack (13) mesh mutually, adjust the one end fixedly connected with fixed block (16) of pole (14) outer disc, fixed slot (15) have been seted up with the junction of fixed block (16) to inner link joint (22).

4. The bucket elevator as claimed in claim 1, wherein: the number of the rectangular blocks (18) is a plurality, the rectangular blocks are annularly distributed on the outer surface of the pin shaft (12), the rectangular blocks (18) are made of hard rubber, and anti-skid grains are arranged on the outer surface of the rectangular blocks.

5. The bucket elevator as claimed in claim 1, wherein: the quantity of hopper (2) is a plurality of, and its all with outer link joint (21) fixed connection on chain (1), and the shape of every hopper is big for inside little opening, and the opening is square, every the internal surface both sides of hopper (2) all are provided with anti-skidding line, and the equal fixedly connected with rubber pad in its bottom.

6. The bucket elevator as claimed in claim 1, wherein: the inner chain plates (22) are connected with the adjusting rods (14) in a sliding mode, the number of the adjusting rods (14) on one inner chain plate (22) is two, the adjusting rods are located on two sides of the inner chain plate (22) respectively, the fixing blocks (16) on the racks (13) are connected with the fixing grooves (15) in a sliding mode, and anti-skidding threads are arranged on the outer surfaces of the fixing blocks (16) and the inner surfaces of the fixing grooves (15).