Logistics interference preventing feeding device for cleaning workshop

Abstract

The invention belongs to the technical field of workpiece conveying, particularly relates to a cleaning workshop feeding device capable of preventing logistics interference, and provides the following scheme aiming at the problems that workpieces are directly placed on a lifting table in the existing using process, and the workpieces can shake and fall off easily in the moving process. The oil scraping device comprises a plurality of oil scraping stations arranged in a stamping workshop and a conveyor erected on the top of a cleaning workshop, the other end of the conveyor extends into the stamping workshop, a deburring station is arranged on one side of each oil scraping station, a lifting machine is arranged on one side of each deburring station, and the lifting machine is arranged on the other side of each deburring station. The discharge ends of the plurality of elevators correspond to the conveyor and are used for conveying workpieces into a cleaning workshop; according to the workpiece lifting device, the workpieces can be moved into the cleaning equipment without adopting a manual transportation mode, the machining efficiency can be effectively improved, the lifting process is more stable, and the workpieces can be automatically pushed to move to the conveyor in the workpiece fixing process.

Description

Technical Field

[0001] The invention relates to the technical field of workpiece conveying, and in particular to a material loading device for a cleaning workshop capable of preventing material flow interference. Background Art

[0002] Parts are processed by different processing equipment, such as oil scraping, deburring, and cleaning. After deburring, the processed workpieces are often moved to the cleaning equipment manually for cleaning, which is inefficient. Some large manufacturers use automated conveying methods for transportation. However, after the conveyor is set up, the space in the factory is reduced, which is inconvenient for maintenance of other equipment. Some manufacturers directly set up the conveyor in the air, which saves space, but a hoist is still needed to lift the processed workpiece onto the conveyor, so that the transportation efficiency remains unchanged and the factory space increases;

[0003] The existing elevator also has the following disadvantages during use:

[0004] 1. When the workpiece is placed directly on the lifting platform during use, it will shake during the movement and easily fall;

[0005] 2. After the lifting platform moves upward, additional pick-and-place equipment is required to remove the workpiece on the lifting platform and place it on the conveyor, further increasing the cost of using the equipment. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art that the workpiece is directly placed on the lifting platform during use, which may cause shaking and easy falling during movement, and to propose a cleaning workshop loading device that prevents logistics interference.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A material loading device for a cleaning workshop to prevent material flow interference, comprising a plurality of oil scraping stations arranged in a stamping workshop, and a conveyor set up on the top of the cleaning workshop, the other end of the conveyor extending into the stamping workshop, a deburring station is arranged on one side of the oil scraping station, a hoist is arranged on one side of the deburring station, and the discharge ends of the plurality of hoists correspond to the conveyor, and are used to transport workpieces into the cleaning workshop;

[0009] A plurality of inlet baskets, each of which is arranged in a cleaning workshop, and a feed end thereof corresponds to a conveyor. A cleaning device is arranged in the cleaning workshop, and a discharge end of the inlet basket corresponds to a feed end of the cleaning device, and is used to automatically convey workpieces to the cleaning device for cleaning;

[0010] The lifting machine comprises a base fixed on the ground, two support frames are fixed on the top of the base, two rotating rollers are rotatably provided between the two support frames, two sprockets are fixedly sleeved on the outer wall of the rotating roller, the outer walls of the two sprockets on the same side are transmission-connected with the same chain, a plurality of first lifting plates for receiving workpieces are fixedly provided on the outer sides of the two chains, a motor is fixedly provided on one side of one of the support frames, and the output end of the motor is fixedly connected to the corresponding rotating roller;

[0011] A support column, the support column is fixedly arranged on the top of the base, and a loading platform corresponding to one of the first lifting plates is fixedly arranged on the top of the support column for temporarily storing the processed workpiece;

[0012] A pushing mechanism is arranged on the two support frames, and is used to push the workpiece on the loading table to the first lifting plate on the right side, and to push the workpiece on the first lifting plate on one side of the conveyor to the conveyor;

[0013] The clamping mechanism is arranged on one side of the first lifting plate and is used in conjunction with the pushing mechanism to fix the workpiece on the first lifting plate after pushing and resetting.

[0014] In a possible design, the pushing mechanism includes two first guide rods sliding through one side of the support frame, the same connecting strip is fixedly provided on one side of the two first guide rods, a first push plate is fixedly provided between the two connecting strips, an electric push rod is fixedly provided on one side of one of the support frames, the output end of the electric push rod is fixedly connected to one of the connecting strips, a connecting platform flush with the loading platform is fixedly provided between the two support frames, and during the pushing process, the bottom of the first push plate is flush with the top of the loading platform, and the top of the left first lifting plate and the top of the right first lifting plate are both flush with the connecting platform.

[0015] In a possible design, a second push plate is fixedly provided between the two connecting strips for pushing the workpiece on the first lifting plate onto the conveyor.

[0016] In a possible design, the clamping mechanism includes a plurality of sliding columns fixedly arranged at the bottom of the first lifting plate, the outer walls of the plurality of sliding columns are slidingly sleeved with the same second lifting plate, the outer wall of the sliding column is sleeved with a first spring, the two ends of the first spring are respectively fixedly connected to the outer wall of the sliding column and the bottom of the second lifting plate, when the first lifting plate on the left side moves to the right side, the second lifting plate is located above the first lifting plate, and one side of the second push plate and the first push plate are both provided with an inclined surface for use with the second lifting plate.

[0017] In a possible design, an extension frame is fixedly provided at one end of the two first guide rods located at the bottom, a fixing bar is fixedly provided on the top of the extension frame, a lifting frame is slidably provided on the top of the fixing bar, two clamping plates are provided on one side of the two lifting frames, and a trapezoidal groove is opened on one side of the clamping plate for use with the first lifting plate and the second lifting plate, so as to limit the two first lifting plates and the second lifting plates on the right side during the resetting process.

[0018] In a possible design, a third guide rod is fixedly provided on the inner wall of the lifting frame, and the third guide rod is slidably provided on the corresponding fixing bar to guide the lifting of the lifting frame.

[0019] In a possible design, two support bars are fixedly provided between the two lifting frames, two second guide rods are slidably provided through one side of the support bar, one end of the second guide rods are fixedly connected to the corresponding clamping plates, a second spring is sleeved on the outer wall of the second guide rod, and the two ends of the second spring are respectively fixedly connected to the side of the support bar and the clamping plate close to each other, so as to limit the first lifting plate and the second lifting plate with different intervals.

[0020] In a possible design, the outer wall fixing sleeve of the sliding column is provided with a limiting ring, and the two limiting rings on one side are fixed with mounting seats, and the mounting seats are fixed on the corresponding chains to retain a gap between the first lifting plate and the second lifting plate.

[0021] Beneficial effects:

[0022] In the present invention, the cleaning workshop loading device for preventing logistics interference is provided with a second lifting plate on the first lifting plate, and a first spring is provided on the sliding column, so that the second lifting plate can be driven to approach the first lifting plate by the elastic force of the first spring, so that the workpiece can be clamped, and inclined surfaces are provided on the first push plate and the second push plate, so that the first lift plate and the second lift plate can be automatically driven to move away from each other during the pushing process, so that the workpiece is easily pushed;

[0023] In the present invention, the cleaning workshop loading device that prevents logistics interference is capable of automatically limiting the two first lifting plates and the second lifting plates on the right side during the resetting process by setting an extension frame and a fixing bar on the two first guide rods located below, and then cooperating with the sliding lifting frame and the clamping plate thereon. This design effectively prevents the lifting plates from shaking and falling off during transportation or lifting, thereby improving logistics efficiency and significantly enhancing the safety of operation. The two lifting frames are connected by a support bar and are provided with an adaptive adjustment mechanism composed of a second guide rod and a second spring. This design enables the clamping plate to be flexibly adjusted and limited according to the first lifting plates and the second lifting plates with different spacings, thereby improving the adaptability and flexibility of the device, so that it can cope with a variety of different logistics scenarios and needs.

[0024] In the present invention, the cleaning workshop loading device for preventing logistics interference effectively ensures that there is enough gap between the first lifting plate and the second lifting plate by arranging a limit ring and a mounting seat on the sliding column and fixing the mounting seat on the chain. This design avoids interference or collision problems caused by insufficient spacing during pushing or lifting, protects the integrity of the equipment, and improves the smoothness of logistics operations.

[0025] In the present invention, there is no need to use manual transportation to move the workpiece into the cleaning equipment, which can effectively improve the processing efficiency, and is more stable during the lifting process. In addition, the workpiece can be automatically pushed onto the conveyor during the process of fixing the workpiece, which is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of a material loading device for a cleaning workshop that prevents material flow interference proposed by the present invention;

[0027] Figure 2 A three-dimensional structural schematic diagram of a hoist of a material loading device for a cleaning workshop that prevents material flow interference proposed by the present invention;

[0028] Figure 3 for Figure 2 Schematic diagram of the three-dimensional structure from another perspective;

[0029] Figure 4 This is a schematic diagram of the sprocket chain structure of a material feeding device for a cleaning workshop that prevents material flow interference proposed by the present invention;

[0030] Figure 5 This is a schematic diagram of the structure of a lifting plate of a material loading device for a cleaning workshop that prevents material flow interference proposed by the present invention;

[0031] Figure 6 This is a schematic diagram of the lifting frame and clamping plate structure of a material loading device for a cleaning workshop that prevents material flow interference proposed by the present invention;

[0032] Figure 7 for Figure 6 Schematic diagram of the structure from another perspective.

[0033] In the figure: 1, stamping workshop; 2, oil scraping station; 3, deburring station; 4, elevator; 5, conveyor; 6, cleaning workshop; 7, cleaning equipment; 8, sub-basket; 9, base; 10, support frame; 11, rotating roller; 12, first lifting plate; 13, first guide rod; 14, connecting strip; 15, first push plate; 16, second push plate; 17, support column; 18, loading platform; 19, motor; 20, electric push rod; 21, sprocket; 22, chain; 23, sliding column; 24, limit ring; 25, first spring; 26, second lifting plate; 27, extension frame; 28, fixing strip; 29, lifting frame; 30, clamping plate; 31, trapezoidal groove; 32, support strip; 33, second guide rod; 34, second spring; 35, third guide rod; 36, mounting seat. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] Example 1

[0036] Reference Figure 1-Figure 7 A feeding device comprises: a stamping workshop 1, a cleaning workshop 6 and the equipment therein. In the stamping workshop 1, a plurality of oil scraping stations 2 are arranged for preliminary oil stain treatment on the workpiece. One side of the oil scraping station 2 is adjacent to the deburring station 3 to further treat the surface of the workpiece. One side of the deburring station 3 is provided with a plurality of hoists 4 for lifting the treated workpiece to a certain height. The discharge ends of these hoists 4 correspond to the conveyor 5 arranged at the top of the cleaning workshop 6 so as to transport the workpiece into the cleaning workshop 6.

[0037] Each elevator 4 includes a base 9 fixed on the ground, and two support frames 10 are arranged on the top of the base 9. Two rotating rollers 11 are rotatably installed between the two support frames 10, and a sprocket 21 is arranged on the outer wall of the rotating roller 11, and the two sprockets 21 on the same side are connected by a chain 22. A plurality of first lifting plates 12 are fixed on the outer side of the chain 22, which are used to receive and lift the workpiece. A motor 19 is fixed on one side of one of the support frames 10, and the output end of the motor 19 is connected to the corresponding rotating roller 11 to drive it to rotate, thereby driving the chain 22 and the first lifting plate 12 to move.

[0038] A support column 17 is also fixed on the top of the base 9 , and a loading platform 18 is provided on the top of the support column 17 , corresponding to one of the first lifting plates 12 , for temporarily storing the workpiece to be lifted.

[0039] The pushing mechanism mainly includes two first guide rods 13 that are slidably arranged on one side of the support frame 10. A connecting strip 14 is fixedly connected to one side of the two first guide rods 13, and a first push plate 15 is fixed between the two connecting strips 14. An electric push rod 20 is fixed to one side of one of the support frames 10, and its output end is connected to one of the connecting strips 14. The left and right movement of the first push plate 15 is controlled by the extension and retraction of the electric push rod 20. When it is necessary to push the workpiece, the electric push rod 20 retracts and pushes the first push plate 15 to push the workpiece on the loading platform 18 to the first lifting plate 12 on the right. In order to ensure smooth pushing, a connecting platform that is flush with the loading platform 18 and the top of the first lifting plates 12 on both sides is also provided between the two support frames 10.

[0040] In order to prevent the workpiece from slipping during the pushing process, a plurality of sliding columns 23 are fixed at the bottom of the first lifting plate 12, and the outer wall of the sliding column 23 is slidably sleeved with a second lifting plate 26. A first spring 25 is also sleeved on the sliding column 23, one end of which is fixed to the sliding column 23, and the other end is fixedly connected to the bottom of the second lifting plate 26. When the first lifting plate 12 on the left side moves to the right side, due to the action of the spring, the second lifting plate 26 will naturally drop and be located above the first lifting plate 12. At this time, one side of the first push plate 15 and the second push plate 16 are both provided with inclined surfaces that cooperate with the second lifting plate 26. When the pushing mechanism pushes the workpiece, these inclined surfaces will first push up the second lifting plate 26, so that it maintains a certain gap with the first lifting plate 12, so as to facilitate the passage of the workpiece; after the pushing is completed, the second lifting plate 26 is reset under the action of the spring, and the workpiece is clamped on the first lifting plate 12 to ensure its stability during the lifting process.

[0041] The present application can be used in the field of workpiece transportation, and can also be used in other fields applicable to the present application.

[0042] Example 2

[0043] refer to Figure 1-Figure 7 , improved on the basis of Example 1: A material loading device for a cleaning workshop that prevents material flow interference, which is applied to the field of workpiece conveying, in order to further improve the stability and safety of the device, one end of the two first guide rods 13 located below is fixed with an extension frame 27. A fixing bar 28 is fixed on the top of the extension frame 27, and a lifting frame 29 is slidably provided on the top of the fixing bar 28. Two clamping plates 30 are respectively provided on one side of the two lifting frames 29, and a trapezoidal groove 31 is designed on one side of the clamping plate 30, and the shape of the trapezoidal groove 31 matches the edge of the first lifting plate 12 and the second lifting plate 26.

[0044] During the pushing process, that is, when the first push plate 15 and the second push plate 16 complete the pushing, they can drive the lifting frame 29 to move to the right, so that the clamping plate 30 is away from the first lifting plate 12 and the second lifting plate 26. At this time, the lifting frame 29 will drop accordingly. When resetting, it can drive the trapezoidal groove 31 on the clamping plate 30 to be accurately inserted between the two first lifting plates 12 and the second lifting plates 26 on the right side, thereby limiting them and preventing them from shaking or falling off during lifting or transportation.

[0045] In order to ensure the stability of the lifting frame 29 during the lifting process, a third guide rod 35 is fixed on its inner wall. The third guide rod 35 penetrates and is slidably arranged on the corresponding fixing bar 28, providing precise guidance for the lifting action of the lifting frame 29, ensuring its stable movement in the vertical direction.

[0046] In order to meet the requirement of limiting the first lifting plate 12 and the second lifting plate 26 at different intervals, two support bars 32 are fixedly arranged between the two lifting frames 29. Two second guide rods 33 are slidably arranged through one side of the support bar 32, and one end of the second guide rod 33 is fixedly connected to the corresponding clamping plate 30. A second spring 34 is sleeved on the outer wall of the second guide rod 33, and the two ends of the second spring 34 are fixedly connected to the side of the support bar 32 and the clamping plate 30 that are close to each other. This design enables the clamping plate 30 to be adaptively adjusted according to the actual interval between the first lifting plate 12 and the second lifting plate 26, and maintain a stable clamping force through the elastic force of the second spring 34, thereby ensuring the limiting effect.

[0047] In order to maintain a certain gap between the first lifting plate 12 and the second lifting plate 26 so that they can be separated smoothly during the pushing process, a stop ring 24 is fixedly sleeved on the outer wall of the sliding column 23. Two stop rings 24 located on one side are fixedly provided with mounting seats 36, and these mounting seats 36 are fixedly arranged on the corresponding chains 22. Through the fixed connection between the mounting seats 36 and the chain 22, it can be ensured that the first lifting plate 12 and the second lifting plate 26 maintain a relatively stable spacing when moving with the chain 22, thereby avoiding interference or collision during the pushing process.

[0048] The first guide rod 13 is moved upwardly to the upper and lower ends of the guide rails 14, and the second guide rails 14 are moved downwardly to the upper and lower ends of the guide rails 14. The second guide rails 14 are moved upwardly to the upper and lower ends of the guide rails 14, and the second guide rails 14 are moved upwardly to the upper and lower ends of the guide rails 14. 3 drives the clamping plate 30 to move outward, so that the clamping plate 30 is away from the corresponding first lifting plate 12 and the second lifting plate 26. When the clamping plate 30 is separated from the first lifting plate 12 and the second lifting plate 26, the clamping plate 30 can drive the lifting frame 29 to move downward by its own gravity, so that the clamping plate 30 below corresponds to the corresponding first lifting plate 12 and the second lifting plate 26, and continue to push. During the movement, the inclined surface on one side of the first push plate 15 can drive the second lifting plate 26 on the right side to move upward, and continue to push the workpiece onto the first lifting plate 12 on the right side. After the pushing is completed, the electric push rod 20 is started to extend, and the first push plate 15 can be driven to reset through the connecting bar 14, and the extension frame 27 can be driven to approach the first lifting plate 12 through the first guide rod 13, so as to drive the clamping plate 30 to approach the first lifting plate 12 and the second lifting plate 26. During the contact movement, the second lifting plate 26 can be driven to approach the first lifting plate 12 to clamp the workpiece in the middle;

[0049] Then the motor 19 is started to drive the first lifting plate 12 on the right side to move upward by one position. The upward movement of the first lifting plate 12 can drive the lifting frame 29 to move upward through the clamping plate 30;

[0050] The materials are loaded in sequence. When the first lifting plate 12 loaded with the workpiece moves to one side of the conveyor 5, the electric push rod 20 retracts to push the workpiece to the first lifting plate 12 on the right side, and the second lifting plate 26 on one side of the conveyor 5 can be driven by the second push plate 16 to move upward to release the fixation of the workpiece. Then, the workpiece can be pushed onto the conveyor 5 by continuing to move, and the conveyor 5 is started to transport the workpiece to the input basket 8, and the workpiece is transported to the cleaning equipment 7 for cleaning through the additional conveyor 5 mechanism on the input basket 8.

[0051] However, as is well known to those skilled in the art, the working principles and wiring methods of the motor 19 and the electric push rod 21 are commonplace, and are conventional means or common knowledge, and will not be elaborated here. Those skilled in the art may make any optional selections according to their needs or convenience.

[0052] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A material feeding device for a cleaning workshop to prevent material flow interference, characterized in that: The invention comprises a plurality of oil scraping stations (2) arranged in a stamping workshop (1), and a conveyor (5) erected on the top of a cleaning workshop (6), wherein the other end of the conveyor (5) extends into the stamping workshop (1), a deburring station (3) is arranged on one side of the oil scraping station (2), and a hoist (4) is arranged on one side of the deburring station (3), and the discharge ends of the plurality of hoists (4) correspond to the conveyor (5) and are used to transport the workpieces to the cleaning workshop (6); A plurality of inlet baskets (8), each of which is arranged in a cleaning workshop (6), and a feed end thereof corresponds to a conveyor (5); a cleaning device (7) is arranged in the cleaning workshop (6), and a discharge end of the inlet basket (8) corresponds to a feed end of the cleaning device (7), and is used to automatically convey workpieces to the cleaning device (7) for cleaning; The lifting machine (4) comprises a base (9) fixed on the ground, two support frames (10) are fixedly provided on the top of the base (9), two rotating rollers (11) are rotatably provided between the two support frames (10), two sprocket wheels (21) are fixedly provided on the outer wall of the rotating roller (11), the outer walls of the two sprocket wheels (21) on the same side are transmission-connected with the same chain (22), a plurality of first lifting plates (12) for receiving workpieces are fixedly provided on the outer sides of the two chains (22), a motor (19) is fixedly provided on one side of one of the support frames (10), and the output end of the motor (19) is fixedly connected to the corresponding rotating roller (11); A support column (17), wherein the support column (17) is fixedly arranged on the top of the base (9), and a loading platform (18) corresponding to one of the first lifting plates (12) is fixedly arranged on the top of the support column (17) for temporarily storing the processed workpiece; A pushing mechanism is arranged on the two support frames (10) and is used to push the workpiece on the loading platform (18) onto the first lifting plate (12) on the right side, and to push the workpiece on the first lifting plate (12) on one side of the conveyor (5) onto the conveyor (5); The clamping mechanism is arranged on one side of the first lifting plate (12) and is used in conjunction with the pushing mechanism to fix the workpiece on the first lifting plate (12) after pushing and resetting.

2. A material handling device for a cleaning workshop to prevent material flow interference according to claim 1, characterized in that: The pushing mechanism comprises two first guide rods (13) which are slidably arranged on one side of the support frame (10); a same connecting strip (14) is fixedly arranged on one side of the two first guide rods (13); a first push plate (15) is fixedly arranged between the two connecting strips (14); an electric push rod (20) is fixedly arranged on one side of one of the support frames (10); an output end of the electric push rod (20) is fixedly connected to one of the connecting strips (14); a connecting platform flush with the loading platform (18) is fixedly arranged between the two support frames (10); during the pushing process, the bottom of the first push plate (15) is flush with the top of the loading platform (18), and the top of the left first lifting plate (12) and the top of the right first lifting plate (12) are both flush with the connecting platform.

3. A material handling device for a cleaning workshop to prevent material flow interference according to claim 2, characterized in that: A second push plate (16) is fixedly provided between the two connecting strips (14) and is used to push the workpiece on the first lifting plate (12) onto the conveyor (5).

4. A material handling device for a cleaning workshop to prevent material flow interference according to claim 3, characterized in that: The clamping mechanism comprises a plurality of sliding columns (23) fixedly arranged at the bottom of the first lifting plate (12); the outer walls of the plurality of sliding columns (23) are slidingly sleeved with the same second lifting plate (26); the outer walls of the sliding columns (23) are sleeved with a first spring (25); the two ends of the first spring (25) are respectively fixedly connected to the outer wall of the sliding column (23) and the bottom of the second lifting plate (26); when the first lifting plate (12) on the left side moves to the right side, the second lifting plate (26) is located above the first lifting plate (12); and one side of the second push plate (16) and the first push plate (15) are both provided with an inclined surface for use with the second lifting plate (26).

5. A material handling device for a cleaning workshop to prevent material flow interference according to claim 4, characterized in that: An extension frame (27) is fixedly provided at one end of the two first guide rods (13) located at the bottom, a fixing strip (28) is fixedly provided at the top of the extension frame (27), a lifting frame (29) is slidably provided at the top of the fixing strip (28), two clamping plates (30) are provided at one side of the two lifting frames (29), and a trapezoidal groove (31) is provided on one side of the clamping plate (30) for use with the first lifting plate (12) and the second lifting plate (26), so as to limit the two first lifting plates (12) and the second lifting plates (26) on the right side during the resetting process.

6. A material handling device for a cleaning workshop to prevent material flow interference according to claim 5, characterized in that: A third guide rod (35) is fixedly provided on the inner wall of the lifting frame (29), and the third guide rod (35) is slidably provided on the corresponding fixing strip (28) to guide the lifting of the lifting frame (29).

7. A material handling device for a cleaning workshop to prevent material flow interference according to claim 5, characterized in that: Two support bars (32) are fixedly arranged between the two lifting frames (29), and two second guide rods (33) are slidably arranged through one side of the support bar (32), and one end of the second guide rod (33) is fixedly connected to the corresponding clamping plate (30), and the outer wall of the second guide rod (33) is sleeved with a second spring (34), and the two ends of the second spring (34) are respectively fixedly connected to the support bar (32) and the clamping plate (30) close to each other, so as to limit the first lifting plate (12) and the second lifting plate (26) with different spacings.

8. The material handling device for cleaning workshops according to claim 4, characterized in that: The outer wall of the sliding column (23) is fixedly sleeved with a limiting ring (24), and two limiting rings (24) on one side are fixedly provided with mounting seats (36), and the mounting seats (36) are fixedly arranged on the corresponding chains (22) for leaving a gap between the first lifting plate (12) and the second lifting plate (26).

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