Automatic cigarette frame unfolding and stacking equipment

Abstract

The utility model discloses automatic cigarette frame unfolding and stacking equipment which comprises a folding and unfolding mechanism and a stacking and unstacking mechanism which are adjacently arranged, and the folding and unfolding mechanism comprises a first rack, a first conveying line and two folding and unfolding assemblies; the first conveying line is arranged in the length direction of the first rack. The two folding and unfolding assemblies are arranged on the two sides of the first conveying line correspondingly, and the cigarette frames can be switched between the folding state and the unfolding state. The stacking and unstacking mechanism comprises a second rack, a second conveying line and two folding tobacco frame lifting assemblies. The second conveying line is arranged in the length direction of the second rack and connected with the first conveying line. The two groups of folded tobacco frame lifting assemblies are respectively arranged on two sides of the second conveying line and can synchronously ascend and descend along the height direction of the second rack, so that the tobacco frames can be automatically folded and stacked when not in use, and can be automatically unstacked and unfolded when in use, the labor intensity is reduced, and the production efficiency is improved. And the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of tobacco production and logistics technology, and in particular to an automatic stacking and palletizing equipment for cigarette frames. Background Technology

[0002] In the leaf sorting workshop and raw tobacco storage room of the tobacco re-drying plant, double-sided tobacco frames are used for storing tobacco leaves and tobacco bales. These frames have two states: unfolded and folded. They need to be unfolded when in use and folded when not in use. Folded frames are typically stacked on pallet racks to save storage space.

[0003] A two-sided cigarette frame typically includes a bottom platform and two frame bodies mounted on the bottom platform, with the frame bodies rotatably connected to the bottom platform. Specifically, the frame bodies include two side columns, a grid frame positioned between the two side columns, and an upper beam located at the top of the two side columns. A hinged rod is mounted on the bottom platform, rotatably connected to the side columns, and a limiting device is installed between them. During folding, the upper beam is first lifted upwards, unlocking the connection between the hinged rod and the side column. Then, the side column is rotated towards the bottom platform, causing the frame body to fold onto the bottom platform, forming a folded state. During unfolding, the side column is first rotated away from the bottom platform, bringing it to a vertical position. Then, the upper beam is lifted upwards, locking the side column and the hinged rod together, forming an unfolded state.

[0004] However, in the current production process, the folding, stacking, unstacking, and unfolding of the cigarette frames all rely on manual labor. Specifically, when not in use, the cigarette frames are folded manually and stacked using forklifts; when in use, they are unstacking using forklifts and unfolding manually. Since both sides of the cigarette frames are used frequently and in large quantities in the re-drying plant, the traditional manual operation method is not only labor-intensive but also significantly reduces production efficiency. Utility Model Content

[0005] To solve the above-mentioned technical problems, the purpose of this utility model is to provide an automatic stacking and palletizing equipment for cigarette frames, which aims to realize the automatic folding, stacking, unstacking and unfolding process of cigarette frames, thereby reducing labor intensity and improving production efficiency.

[0006] The technical solution provided by this utility model is as follows:

[0007] An automatic stacking and palletizing device for cigarette frames includes a folding and unfolding mechanism and a stacking and destacking mechanism arranged adjacent to each other, wherein the folding and unfolding mechanism includes:

[0008] First rack;

[0009] The first conveyor line is arranged along the length of the first frame;

[0010] Two sets of folding and unfolding components are respectively set on both sides of the first conveyor line, which enables the cigarette frame to switch between folded and unfolded states;

[0011] The palletizing and depalletizing mechanism includes:

[0012] Second rack;

[0013] The second conveyor line is arranged along the length of the second frame and is connected to the first conveyor line;

[0014] Two sets of folding cigarette frame lifting components are respectively installed on both sides of the second conveyor line, and can rise and fall synchronously along the height direction of the second frame.

[0015] Furthermore, the folding and unfolding mechanism also includes a lifting device, which is connected to the folding and unfolding assembly.

[0016] Furthermore, each set of the folding and unfolding components includes:

[0017] The flip bracket is rotatably mounted on the side of the first frame;

[0018] A clamping device is mounted on the flipping bracket to clamp the side post of the cigarette frame and rotate with the flipping bracket.

[0019] The lifting device, mounted on the tilting bracket, can abut against the upper beam of the cigarette frame.

[0020] Furthermore, each set of the folding and unfolding components includes two clamping devices, which are respectively used to clamp the two side posts of the cigarette frame.

[0021] Furthermore, the flipping bracket includes:

[0022] A rotating shaft is arranged along the length of the first frame and is connected to a drive device;

[0023] Two support columns are respectively installed at both ends of the rotating shaft;

[0024] An mounting plate is disposed between the two support columns for mounting the clamping device.

[0025] Furthermore, the lifting device includes:

[0026] The lifting plate is used to support the upper beam of the smoke frame;

[0027] The lifting cylinder has one end connected to the lifting plate and the other end passing through the mounting plate and connected to the rotating shaft.

[0028] Furthermore, each set of the folding cigarette frame lifting assembly includes:

[0029] The lifting frame is slidably positioned along the height direction of the second frame;

[0030] A rotating forklift device includes a rotating shaft and a forklift plate mounted on the rotating shaft, the rotating shaft being mounted on the lifting frame.

[0031] Furthermore, the automatic stacking and palletizing equipment for cigarette frames also includes a chain conveyor, which is located at the end of the folding and unfolding mechanism away from the stacking and destacking mechanism, and is used for loading and unloading cigarette frames.

[0032] Furthermore, the chain conveyor includes:

[0033] Third rack;

[0034] The third conveyor line includes two conveyor chain assemblies arranged parallel to each other along the length of the third frame, and a roller support conveyor bar arranged between the two conveyor chain assemblies.

[0035] A smoke frame detection sensor is installed on the third conveyor line.

[0036] Furthermore, the chain conveyor also includes:

[0037] A smoke frame blocking device is disposed at the end of the third frame away from the folding and unfolding mechanism;

[0038] The smoke frame guide guard is set on both sides of the third frame along its length.

[0039] Compared with the prior art, the automatic stacking and palletizing equipment for cigarette frames provided in this embodiment of the present invention has at least the following technical effects:

[0040] The automatic stacking and palletizing equipment for cigarette frames includes a folding / unfolding mechanism and a palletizing / destacking mechanism arranged adjacent to each other. The folding / unfolding mechanism includes a first frame, a first conveyor line, and two sets of folding / unfolding components. The first conveyor line runs along the length of the first frame. The two sets of folding / unfolding components are respectively located on both sides of the first conveyor line, enabling the cigarette frames to switch between folded and unfolded states. The palletizing / destacking mechanism includes a second frame, a second conveyor line, and two sets of folding cigarette frame lifting components. The second conveyor line runs along the length of the second frame and is connected to the first conveyor line. The two sets of folding cigarette frame lifting components are respectively located on both sides of the second conveyor line, enabling them to rise and fall synchronously along the height of the second frame. This structure allows for automatic folding and palletizing of the cigarette frames when not in use, and automatic destacking and unfolding when needed, reducing labor intensity and improving production efficiency. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of an automatic stacking and palletizing device for cigarette frames according to one embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the folding and unfolding mechanism in one embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the stacking and destacking mechanism in one embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the chain conveyor structure in one embodiment of the present invention. Figure 1 ;

[0046] Figure 5 This is a schematic diagram of the chain conveyor structure in one embodiment of the present invention. Figure 2 .

[0047] Figure label:

[0048] 10. Folding and unfolding mechanism; 11. First frame; 12. First conveyor line; 131. Tilting bracket; 1311. Rotating shaft; 1312. Support column; 1313. Mounting plate; 1314. Drive device; 132. Clamping device; 133. Lifting device; 1331. Lifting plate; 1332. Lifting cylinder; 14. Lifting device;

[0049] 20. Palletizing and depalletizing mechanism; 21. Second frame; 22. Second conveyor line; 231. Lifting frame; 2321. Rotating shaft; 2322. Forklift plate; 24. Power unit;

[0050] 30. Chain conveyor; 31. Third frame; 321. Conveyor chain assembly; 322. Roller support conveyor bar; 33. Smoke frame detection sensor; 34. Smoke frame blocking device; 35. Smoke frame guide guard; 36. Chain conveyor power unit. Detailed Implementation

[0051] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0052] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0053] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0055] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this utility model can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0056] Please refer to the attached document. Figure 1 To be continued Figure 3As shown, one embodiment of this utility model provides an automatic stacking and palletizing device for tobacco frames, including a folding and unfolding mechanism 10 and a stacking and destacking mechanism 20 arranged adjacent to each other. The folding and unfolding mechanism 10 includes a first frame 11, a first conveyor line 12, and two sets of folding and unfolding components. The first conveyor line 12 is arranged along the length direction of the first frame 11. The two sets of folding and unfolding components are respectively arranged on both sides of the first conveyor line 12, enabling the tobacco frames to switch between a folded state and an unfolded state. The stacking and destacking mechanism 20 includes a second frame 21, a second conveyor line 22, and two sets of folding tobacco frame lifting components. The second conveyor line 22 is arranged along the length direction of the second frame 21 and is connected to the first conveyor line 12. The two sets of folding tobacco frame lifting components are respectively arranged on both sides of the second conveyor line 22, enabling them to rise and fall synchronously along the height direction of the second frame 21. This automatic stacking and palletizing device for tobacco frames is suitable for folding tobacco frames on both sides of tobacco leaves and tobacco bag carriers. The system includes a folding / unfolding station on the first conveyor line 12, with two sets of folding / unfolding components installed there. A palletizing / depalletizing station is located on the second conveyor line 22, with two sets of folding cigarette frame lifting components installed there. During folding, the first conveyor line 12 transports the cigarette frames to the folding / unfolding station for folding. After folding, the first conveyor line 12 transports the folded cigarette frames to the second conveyor line 22, which then transports them to the palletizing / depalletizing station for palletizing. During unfolding, the second conveyor line 22 transports the depalletized folded cigarette frames from the palletizing / depalletizing station back to the first conveyor line 12. The first conveyor line 12 then transports the folded cigarette frames to the folding / unfolding station for unfolding. After unfolding, the first conveyor line 12 transports the unfolded cigarette frames to a preset target position.

[0057] In this embodiment, the automatic stacking and palletizing equipment for cigarette frames includes a folding and unfolding mechanism 10 and a palletizing and destabilizing mechanism 20 arranged adjacent to each other. The folding and unfolding mechanism 10 includes a first frame 11, a first conveyor line 12, and two sets of folding and unfolding components. The first conveyor line 12 is arranged along the length of the first frame 11. The two sets of folding and unfolding components are respectively arranged on both sides of the first conveyor line 12, enabling the cigarette frames to switch between a folded state and an unfolded state. The palletizing and destabilizing mechanism 20 includes a second frame 21, a second conveyor line 22, and two sets of folding cigarette frame lifting components. The second conveyor line 22 is arranged along the length of the second frame 21 and is connected to the first conveyor line 12. The two sets of folding cigarette frame lifting components are respectively arranged on both sides of the second conveyor line 22, enabling them to rise and fall synchronously along the height direction of the second frame 21. This structure enables the automatic folding and palletizing of cigarette frames when they are not in use, and the automatic destabilizing and unfolding of cigarette frames when they are needed, reducing labor intensity and improving production efficiency.

[0058] In some alternative embodiments, the folding and unfolding mechanism 10 further includes a lifting device 14 connected to the folding and unfolding assembly. The lifting device 14 is capable of driving the folding and unfolding assembly to rise and fall.

[0059] In some optional embodiments, each folding and unfolding assembly includes a flipping bracket 131, a clamping device 132, and a lifting device 133; wherein, the flipping bracket 131 is rotatably mounted on the side end of the first frame 11; the clamping device 132 is disposed on the flipping bracket 131 for clamping the side post of the cigarette frame and rotating with the flipping bracket 131; the lifting device 133 is disposed on the flipping bracket 131 and can abut against the upper beam of the cigarette frame and lift the upper beam upward, so that the short rod and the hinge rod of the cigarette frame are unlocked or locked.

[0060] In some optional embodiments, each folding and unfolding assembly includes two clamping devices 132, which are used to clamp the two side posts of the cigarette frame. The clamping devices 132 can take various forms, such as cylinder grippers, and the specific type can be selected according to actual needs, but is not limited to these.

[0061] In some optional embodiments, the flipping bracket 131 includes a rotating shaft 1311, two support columns 1312, and a mounting plate 1313. The rotating shaft 1311 is arranged along the length of the first frame 11 and is connected to a drive device 1314. The two support columns 1312 are respectively disposed at both ends of the rotating shaft 1311. The mounting plate 1313 is disposed between the two support columns 1312 for mounting the clamping device 132. The drive device 1314 drives the rotating shaft 1311 to rotate, thereby driving the support columns 1312 and the clamping device 132 to rotate synchronously. During this process, the clamping device 132 clamps the side column of the cigarette frame, thereby driving the frame body of the cigarette frame to rotate together.

[0062] In some optional embodiments, the lifting device 133 includes a lifting plate 1331 and a lifting cylinder 1332; the lifting plate 1331 abuts against the upper beam of the cigarette frame; one end of the lifting cylinder 1332 is connected to the lifting plate 1331, and the other end passes through the mounting plate 1313 and is connected to the rotating shaft 1311. During folding, the lifting cylinder 1332 first drives the lifting plate 1331 to move upward, thereby lifting the upper beam upward and unlocking the connection between the hinge rod and the side column. Then, the flipping bracket 131 drives the cigarette frame side column to rotate towards the bottom platform, thereby folding the frame body onto the bottom platform to form a folded state. During unfolding, the flipping bracket 131 first drives the cigarette frame side column to rotate away from the bottom platform, causing the side column to rotate to a vertical state. Then, the lifting cylinder 1332 drives the lifting plate 1331 to move upward, thereby lifting the upper beam upward and locking the side rod and the hinge rod to form an unfolded state.

[0063] In some optional embodiments, each folding cigarette frame lifting assembly includes a lifting frame 231 and a rotating forklift device; the lifting frame 231 is slidably disposed in the height direction of the second frame 21; the rotating forklift device includes a rotating shaft 2321 and a forklift plate 2322 mounted on the rotating shaft 2321, the rotating shaft 2321 being mounted on the lifting frame 231. Driven by the power unit 24, the lifting frame 231 can slide up and down along the height direction of the second frame 21, causing the rotating shaft 2321 and the forklift plate 2322 to rise and fall accordingly. During the stacking process, the forklift plate 2322 picks up and carries the folded cigarette frames. The power unit 24 drives the lifting frame 231 to move upward, lifting the folded cigarette frames on the forklift plate 2322. At this time, the first conveyor line 12 can transport a new folded cigarette frame to the second conveyor line 22, which places it below the already lifted cigarette frame. Then, the lifting frame 231 is lowered, so that the lifted cigarette frame falls on the newly transported cigarette frame, thus completing the stacking operation. During the destacking process, the forklift plate 2322 picks up and lifts all cigarette frames except the bottom layer, leaving the bottom layer cigarette frames alone in their original position. At this time, the bottom layer cigarette frames that are not lifted can be transferred to the first conveyor line 12 via the second conveyor line 22 for unfolding. Optionally, the lifting frame 231 slides up and down under the action of the motor sprocket and chain of the power unit 24.

[0064] Please refer to the attached document. Figure 4 and attached Figure 5 As shown, in some optional embodiments, the automatic stacking and palletizing equipment for cigarette frames further includes a chain conveyor 30. The chain conveyor 30 is located at the end of the folding and unfolding mechanism 10 away from the stacking and destacking mechanism 20, and is used for loading and unloading the cigarette frames. Specifically, when the cigarette frames need to be folded and stacked, the chain conveyor 30 is used to receive the unfolded cigarette frames and smoothly transport them to the folding and unfolding mechanism 10 for subsequent folding processing, i.e., to realize the loading operation; when the cigarette frames need to be destacking and unfolded, the chain conveyor 30 is used to receive the unfolded cigarette frames processed by the folding and unfolding mechanism 10 and transport the unfolded cigarette frames to a preset unloading port, i.e., to realize the unloading operation.

[0065] In some optional embodiments, the chain conveyor 30 includes a third frame 31, a third conveyor line, and a smoke frame detection sensor 33; the third conveyor line includes two conveyor chain assemblies 321 arranged parallel to each other along the length of the third frame 31 and a roller support conveyor bar 322 disposed between the two conveyor chain assemblies 321; the smoke frame detection sensor 33 is disposed on the third conveyor line.

[0066] In some alternative embodiments, the chain conveyor 30 further includes a smoke frame blocking device 34 and a smoke frame guide guard 35; the smoke frame blocking device 34 is disposed at the end of the third frame 31 away from the folding and unfolding mechanism 10; the smoke frame guide guard 35 is disposed on opposite sides of the third frame 31 in the length direction to increase the stability of the smoke frame during folding and unfolding.

[0067] It should be further noted that the chain conveyor 30 also includes a chain conveyor power unit 36 ​​to provide power for conveying the chain assembly 321.

[0068] The working process of the automatic stacking and palletizing equipment for cigarette frames is as follows: When the cigarette frames are not in use, the lifting device 14 drives the folding and unfolding assembly to rise, causing the flipping bracket 131, clamping device 132, and lifting device 133 to rise to the preset position. Subsequently, the flipping bracket 131 begins to rotate, moving the clamping device 132 closer to the side column of the cigarette frame, where the clamping device 132 clamps the side column of the cigarette frame. The lifting cylinder 1332 of the lifting device 133 drives the lifting plate 1331 to move upward, lifting the upper beam upward, thereby unlocking the connection between the hinge rod and the side column. At this time, the flipping bracket 131 drives the clamping device 132, the lifting device 133, and the frame body of the cigarette frame to rotate together, laying the cigarette frame down on the bottom platform. The cigarette frame has two frame bodies; through the same sequence of actions, the other frame body is also folded, ultimately achieving a double-sided folded state for the cigarette frame. Next, the stacking and destacking mechanism 20 transports the folded two-sided cigarette frames to the stacking and destacking station via the second conveyor line 22. The forklift plate 2322 picks up and carries the folded cigarette frames at this point. The power unit 24 drives the lifting frame 231 to move upward, lifting the cigarette frames on the forklift plate 2322. At this time, the first conveyor line 12 transports the new folded cigarette frames to the second conveyor line 22, which places them below the already lifted cigarette frames. Subsequently, the lifting frame 231 descends, placing the lifted cigarette frames onto the newly transported cigarette frames. Next, the forklift plate 2322 rotates and continues to descend to the bottom of the stacked two layers of cigarette frames, picking up and lifting the stacked two layers of cigarette frames, waiting for the third layer of cigarette frames to be transported, and continuing the stacking. Through this process, a specified number of cigarette frames are finally stacked, thus realizing the automatic feeding, folding, and stacking of cigarette frames.

[0069] Conversely, when the cigarette frames are needed, the stacking and destacking mechanism 20 first performs the destacking operation. Then, the folding and unfolding mechanism 10 unfolds the folded cigarette frames one by one and conveys them to the unloading port of the chain conveyor 30, so that the equipment can take away the unfolded cigarette frames, thereby automating the destacking, unfolding and unloading process of the folded multi-layer cigarette frames.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tobacco bale automatic stacking and unstacking apparatus, characterized in that, The folding and unfolding mechanism and the stacking and unstacking mechanism are arranged adjacently, and the folding and unfolding mechanism comprises: a first rack; a first conveying line arranged along the length direction of the first rack; two groups of folding and unfolding assemblies arranged on the two sides of the first conveying line, which can switch the cigarette frame between the folded state and the unfolded state; the stacking and unstacking mechanism comprises: a second rack; a second conveying line arranged along the length direction of the second rack and connected with the first conveying line; two groups of folding cigarette frame lifting assemblies arranged on the two sides of the second conveying line, which can be lifted and lowered along the height direction of the second rack synchronously.

2. The carton unstacking and stacking apparatus of claim 1, wherein, The folding and unfolding mechanism further comprises a lifting device connected with the folding and unfolding assemblies.

3. The carton unstacking and stacking apparatus of claim 2, wherein, Each group of the folding and unfolding assemblies comprises: a turnover support rotatably installed on the side end of the first rack; a clamping device arranged on the turnover support for clamping the side column of the cigarette frame and rotating with the turnover support; a jacking device arranged on the turnover support and capable of abutting against the upper beam of the cigarette frame.

4. The carton unstacking and stacking apparatus of claim 3, wherein, Each group of the folding and unfolding assemblies comprises two clamping devices for clamping two side columns of the cigarette frame.

5. The carton unstacking and stacking apparatus of claim 3, wherein, The turnover support comprises: a rotating shaft arranged along the length direction of the first rack and connected with a driving device; two support columns arranged on the two ends of the rotating shaft; a mounting plate arranged between the two support columns for mounting the clamping device.

6. The carton unstacking and stacking apparatus of claim 5, wherein, The jacking device comprises: a jacking plate for abutting against the upper beam of the cigarette frame; a jacking cylinder having one end connected with the jacking plate and the other end penetrating through the mounting plate and connected with the rotating shaft.

7. The carton unstacking and stacking apparatus of claim 1, wherein, Each group of the folding cigarette frame lifting assemblies comprises: a lifting frame slidingly arranged along the height direction of the second rack; a rotating fork device comprising a rotating shaft and a fork plate mounted on the rotating shaft, and the rotating shaft is mounted on the lifting frame.

8. The carton unstacking and stacking apparatus of claim 1, wherein, Further comprising a chain conveyor arranged at the end of the folding and unfolding mechanism away from the stacking and unstacking mechanism for feeding and discharging the unfolded cigarette frame.

9. The carton unstacking and stacking apparatus of claim 8, wherein, The chain conveyor comprises: a third rack; a third conveying line comprising two conveying chain assemblies arranged in parallel along the length direction of the third rack and a roller support conveying strip arranged between the two conveying chain assemblies; a cigarette frame detection sensor arranged on the third conveying line.

10. The carton unstacking and stacking apparatus of claim 9, wherein, The chain conveyor further comprises: a cigarette frame blocking device arranged at the end of the third rack away from the folding and unfolding mechanism; a cigarette frame guide edge arranged on the opposite sides of the length direction of the third rack.

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