A foldable cold chain transport insulation box

Abstract

The utility model relates to cold chain logistics technical field discloses a kind of foldable cold chain transport insulation box, including lid, bottom plate, side plate, front plate, back plate, fixed and connecting assembly.Lid contains box cover with buckle, bottom plate has bottom support plate and fixing part, side plate, front plate, back plate are connected bottom plate through hinged / rotary shaft respectively, fixed assembly contains upper frame with frame buckle and clamping groove, connecting assembly has bottom foot and top foot.The device can be unfolded to form a sealed insulation box, and the frame buckle is connected to the clamping groove of each plate to ensure stability. When folding, each plate is inwardly stored, the buckle is switched to connect and fix, and the volume is greatly reduced. The top foot and the bottom foot are adapted to realize multi-box stacking, the empty box saves storage and transportation space, and adapts to the efficient transportation and insulation needs of cold chain logistics.

Description

Technical Field

[0001] This utility model relates to the field of cold chain logistics technology, specifically a foldable insulated box for cold chain transportation. Background Technology

[0002] The safety of cold chain transportation is ensured by the structural design and functional configuration of insulated boxes. In existing technologies, the design of isolating hot and cold airflows through heat insulation components and sealing components is already quite common.

[0003] A search revealed existing technology (application number: CN118850518B), which describes "a cold chain transport insulated box". This utility model achieves the function of replacing the cold storage box without opening the box body through the movement of the cold storage box.

[0004] However, while existing technologies have improved insulation performance and sample safety to some extent, they still have some shortcomings: their overall structure is fixed and does not support folding or compression; when empty, they occupy a large amount of storage and transportation space, leading to increased logistics costs. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a foldable insulated cold chain transport box.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a foldable cold chain transport insulated box, comprising: a lid assembly, including a lid for sealing the top of the insulated box; a bottom plate assembly, including a bottom support plate disposed below the lid for forming the bottom structure of the insulated box and supporting the contents; a side plate assembly, including two sets of side support plates symmetrically disposed between the lid and the bottom support plate for forming the side structure of the insulated box and providing lateral support for the contents; a front plate assembly, including a front support plate disposed between the lid and the bottom support plate for forming the front structure of the insulated box; a rear plate assembly, including a rear support plate disposed between the lid and the bottom support plate for forming the rear structure of the insulated box; a fixing assembly, including an upper frame rotatably connected to the lid via hinges for connecting and fixing the lid to the side support plates, front support plates, and rear support plates; and a connecting assembly, including feet fixed to the bottom of the bottom support plate for supporting the entire device.

[0007] As a further description of the above technical solution:

[0008] The lid assembly also includes: a lid clip, which is fixed to the lid; the fixing assembly also includes: a frame slot, which is opened on the upper frame and is used to lock the lid in place with the lid clip to ensure the sealing effect of the lid; and a frame clip, which is provided in multiple sets and is evenly fixed to the lower part of the upper frame to connect the lower parts and ensure the splicing stability of the entire device.

[0009] As a further description of the above technical solution:

[0010] The base plate assembly also includes: two sets of fasteners symmetrically arranged and fixed to both sides of the base support plate, with the bottom of the side support plate hinged to the fasteners for supporting the side support plate; a fixing plate fixed to the side support plate for supporting the rear support plate; and a base plate slot formed on the fasteners, in which the frame buckle part engages with the base plate slot when folded for fixing the upper frame when folded.

[0011] As a further description of the above technical solution:

[0012] The side panel assembly also includes: a side panel slot one, which is opened on the outside of the side support plate, and when folded, part of the frame is snapped into the side panel slot one to fix the upper frame when folded; and a side panel slot two, which is opened on the top of the side support plate, and when unfolded, part of the frame is snapped into the side panel slot two to fix the upper frame when unfolded.

[0013] As a further description of the above technical solution:

[0014] The front panel assembly also includes: a pivot shaft 1, fixedly mounted on the bottom of the front support plate and rotatably mounted on the bottom support plate at both ends, for providing a pivot point for the front support plate; and a front panel slot, formed on the top of the front support plate, in which a portion of the frame is snapped into during unfolding, for fixing the upper frame during unfolding. The rear panel assembly also includes: a pivot shaft 2, fixedly mounted on the bottom of the rear support plate and rotatably mounted on the bottom support plate at both ends, for providing a pivot point for the rear support plate; and a rear panel slot, formed on the top of the rear support plate, in which a portion of the frame is snapped into during unfolding, for fixing the upper frame during unfolding.

[0015] As a further description of the above technical solution:

[0016] The connecting components also include: a top foot, which is fixed to the top of the box cover and can be snapped into place with the bottom foot, used to cooperate with the bottom foot of the lower insulated box when multiple insulated boxes are stacked to achieve stacking positioning.

[0017] As a further description of the above technical solution:

[0018] The insulated box has two states: an unfolded state and a folded state. When the insulated box is in the folded state, the front support plate, rear support plate, and side support plate are folded inward in sequence, and the frame buckles are engaged in the side plate slot one and the bottom plate slot. When the insulated box is in the unfolded state, the side support plate, rear support plate, and front support plate are opened outward in sequence, and the frame buckles are engaged in the side plate slot two, the front plate slot, and the pivot two, ensuring that the side support plate, rear support plate, and front support plate are stable when unfolded.

[0019] This utility model has the following beneficial effects:

[0020] 1. Through multi-component linkage folding and precise buckle positioning, the system achieves the dual requirements of "stable unfolding and space-saving folding". When unfolded, the side, front, and rear support plates unfold via pivots and fasteners. The frame buckles of the upper frame engage with the side plate slots, front plate slots, and rear plate slots, quickly forming a stable box structure. When folded, each support plate is sequentially folded inward, and the frame buckles switch to engage with the side plate slots and bottom plate slots for fixation, significantly reducing the volume. This saves a lot of space when transporting or storing the empty box, reducing logistics and storage costs.

[0021] 2. Through a sealed design and stacking structure, it balances cold chain insulation with convenient transportation. The lid is locked in place by a lid clip and a frame slot on the upper frame, ensuring the container is sealed to maintain a low internal temperature environment, meeting the insulation requirements of cold chain transportation; the top feet of the lid and the bottom feet of the base plate can be precisely engaged to prevent tipping when multiple boxes are stacked, improving transportation and loading efficiency; the entire box can be unfolded and folded without additional tools, making it easy to operate and perfectly meeting the core requirements of "efficient space utilization + stable insulation + convenient operation" in cold chain scenarios. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a foldable insulated cold chain transport box when unfolded, as proposed in this utility model.

[0023] Figure 2 This is a schematic diagram of the overall structure of a foldable insulated cold chain transport box when opened, as proposed in this utility model.

[0024] Figure 3 This is an exploded view of the overall structure of a foldable insulated cold chain transport box when opened, as proposed in this utility model.

[0025] Figure 4 This is a schematic diagram of the overall structure of a foldable insulated cold chain transport box when folded, as proposed in this utility model.

[0026] Figure 5 This is an exploded view of the overall structure of a foldable insulated cold chain transport box proposed in this utility model when folded.

[0027] Figure 6 This is a schematic diagram of the overall structure of a foldable insulated cold chain transport box when it is folded and stacked in multiple layers, as proposed in this utility model.

[0028] Legend:

[0029] 11. Lid; 12. Lid clip; 21. Base; 22. Top foot; 31. Upper frame; 32. Frame slot; 33. Frame clip; 41. Side support plate; 42. Side plate slot one; 43. Side plate slot two; 51. Front support plate; 52. Rotating shaft one; 53. Front plate slot; 61. Bottom support plate; 62. Fastener; 63. Fixing plate; 64. Bottom plate slot; 71. Rear support plate; 72. Rotating shaft two; 73. Rear plate slot. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0031] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The utility model will be further described in detail below with reference to the accompanying drawings.

[0032] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0033] Example 1:

[0034] like Figures 1 to 6As shown, this embodiment provides a foldable insulated cold chain transport box, comprising: a lid assembly, including a lid 11 for sealing the top of the box; a bottom plate assembly, including a bottom support plate 61 disposed below the lid 11 for forming the bottom structure of the box and supporting the contents; a side plate assembly, including two sets of side support plates 41 symmetrically disposed between the lid 11 and the bottom support plate 61 for forming the side structure of the box and providing lateral support for the contents; and a front plate assembly, including a front support plate 5. 1. A front structure of the insulated box is formed between the lid 11 and the bottom support plate 61; 2. A rear support plate assembly, including a rear support plate 71, is formed between the lid 11 and the bottom support plate 61; 3. A fixing assembly, including an upper frame 31, is rotatably connected to the lid 11 via a hinge, and is used to connect and fix the lid 11 to the side support plate 41, the front support plate 51, and the rear support plate 71; 4. A connecting assembly, including a base 21, is fixed to the bottom of the bottom support plate 61 and is used to support the entire device.

[0035] In this embodiment, the lid assembly, connecting assembly, fixing assembly, side panel assembly, front panel assembly, bottom panel assembly, and rear panel assembly constitute a foldable cold chain transport insulated box according to this application.

[0036] Understandable, Figure 1 The diagram only schematically shows some of the components included in the insulated box; the actual shape, size, location, and construction of these components are not subject to change. Figure 1 Due to limitations, insulated boxes can also include, compared to Figure 1 More or fewer parts.

[0037] In addition, in this embodiment, the base 21 is made of rubber; the lid 11 covers and seals the top of the insulated box; the bottom support plate 61 carries the items inside the box; the side support plate 41, the front support plate 51, and the rear support plate 71 are spliced ​​together to form the side and front and rear parts of the box; the upper frame 31 rotates around the hinge to connect and fix the lid 11 and each support plate; the base 21 supports the entire device and prevents the bottom from directly contacting the ground; the base 21 is non-slip and has no risk of tipping over.

[0038] Specifically, the lid assembly also includes a lid clip 12, which is fixed to the lid 11; the fixing assembly also includes: a frame slot 32, which is opened on the upper frame 31, used to cooperate with the lid clip 12 to lock the position of the lid 11 and ensure the sealing effect of the lid 11; and a frame clip 33, which is provided in multiple sets and is evenly fixed to the lower part of the upper frame 31, used to connect the lower parts and ensure the splicing stability of the entire device.

[0039] In this embodiment, when the lid 11 is closed, the lid buckle 12 is inserted into the frame slot 32 to lock the lid 11 to the upper frame 31; the frame buckle 33 engages with the slots of the lower support plates to fix the relative position of the upper frame 31 and the support plates, ensuring the stability of the splicing; the lid buckle 12 and the frame slot 32 cooperate to improve the sealing performance of the lid 11; after the frame buckle 33 is engaged, there is no loosening or breakage after long-term use.

[0040] Specifically, the base plate assembly also includes: two sets of fasteners 62, which are symmetrically arranged and fixed to both sides of the base support plate 61, and the bottom of the side support plate 41 is hinged to the fasteners 62 to support the side support plate 41; a fixing plate 63, which is fixed to the side support plate 41 to support the rear support plate 71; and a base plate slot 64, which is formed on the fasteners 62. When folded, the frame buckle 33 is partially engaged in the base plate slot 64 to fix the upper frame 31 when folded.

[0041] In a preferred embodiment, the fixing member 62 provides support and hinge fulcrum for the side support plate 41, allowing the side support plate 41 to rotate around the fixing member 62; the fixing plate 63 supports the rear support plate 71 in the unfolded state, preventing the rear support plate 71 from tilting inward; when folded, the frame buckle 33 engages with the bottom plate slot 64, fixing the relative position of the upper frame 31 and the bottom support plate 61; the side support plate 41 can rotate around the fixing member 62 at an angle range of 0-90°; in the folded state, the frame buckle 33 and the bottom plate slot 64 are firmly engaged, and the upper frame 31 does not shift.

[0042] Example 2:

[0043] Based on Embodiment 1, in order to further improve folding efficiency, a side plate assembly is arranged above the bottom support plate 61;

[0044] Specifically, the side panel assembly also includes: a side panel slot 1 42, which is opened on the outside of the side support plate 41, and when folded, part of the frame buckle 33 is engaged in the side panel slot 1 42 to fix the upper frame 31 when folded; and a side panel slot 2 43, which is opened on the top of the side support plate 41, and when unfolded, part of the frame buckle 33 is engaged in the side panel slot 2 43 to fix the upper frame 31 when unfolded.

[0045] In this embodiment, when the insulated box is folded, the side support plate 41 rotates inward to fit against the bottom support plate 61, and the frame buckle 33 is engaged in the side plate slot 1 42 to fix the upper frame 31 and the side support plate 41; when unfolded, the side support plate 41 rotates outward to a vertical state, and the frame buckle 33 is engaged in the side plate slot 2 43 to lock the unfolded position of the side support plate 41; the folded and unfolded states can be quickly switched; the frame buckle 33 cooperates with the slot to fix the side support plate 41 without shaking.

[0046] Specifically, the front panel assembly further includes: a pivot 52, fixedly mounted on the bottom of the front support plate 51, with both ends rotatably mounted on the bottom support plate 61, for providing a pivot point for the front support plate 51; and a front panel slot 53, formed on the top of the front support plate 51, in which a portion of the frame clips 33 are engaged when unfolded, for fixing the upper frame 31 when unfolded. The rear panel assembly further includes: a pivot 72, fixedly mounted on the bottom of the rear support plate 71, with both ends rotatably mounted on the bottom support plate 61, for providing a pivot point for the rear support plate 71; and a rear panel slot 73, formed on the top of the rear support plate 71, in which a portion of the frame clips 33 are engaged when unfolded, for fixing the upper frame 31 when unfolded.

[0047] With this configuration, the front support plate 51 rotates around pivot 52, and the rear support plate 71 rotates around pivot 72, enabling the folding and unfolding of the front and rear plates. When unfolded, the front support plate 51 and the rear support plate 71 rotate to a vertical position, and the frame buckles 33 respectively engage with the front plate slot 53 and the rear plate slot 73 to lock the positions of the front and rear plates. The rotation angle range of the front support plate 51 and the rear support plate 71 is 0-90°, and the rotation is smooth without any jamming. After the frame buckles 33 engage with the slots, there is no displacement or tilting of the front and rear plates.

[0048] Example 3:

[0049] Based on embodiment 2, in order to further improve folding efficiency, a connecting component is arranged above the lid 11 and below the bottom support plate 61;

[0050] Specifically, the connecting components also include: a top foot 22, which is fixed to the top of the box cover 11 and can be snapped into place with the bottom foot 21, so as to cooperate with the bottom foot 21 of the lower insulated box when multiple insulated boxes are stacked to achieve stacking positioning.

[0051] The top foot 22 is made of nitrile rubber. When multiple insulated boxes are stacked, the bottom foot 21 of the upper insulated box is inserted into the groove of the top foot 22 of the lower insulated box to achieve stacking positioning and prevent the insulated boxes from shifting laterally during stacking. The top foot 22 and the bottom foot 21 cooperate to stack multiple layers at a time. After stacking, there is no risk of tipping over, and the stacking stability meets the requirements of cold chain transportation.

[0052] Specifically, the insulated box has two states: an unfolded state and a folded state. When the insulated box is in the folded state, the front support plate 51, the rear support plate 71, and the side support plate 41 are folded inward in sequence, and the frame buckle 33 is engaged in the side plate slot 42 and the bottom plate slot 64. When the insulated box is in the unfolded state, the side support plate 41, the rear support plate 71, and the front support plate 51 are opened outward in sequence, and the frame buckle 33 is engaged in the side plate slot 43, the front plate slot 53, and the pivot 72, ensuring that the side support plate 41, the rear support plate 71, and the front support plate 51 are stable when unfolded.

[0053] In this embodiment, during the folding operation, first unlock the frame buckle 33, then rotate the front support plate 51, rear support plate 71, and side support plate 41 in sequence inward, and then snap the frame buckle 33 into the corresponding slot to fix it; during the unfolding operation, unlock the frame buckle 33, then rotate the side support plate 41, rear support plate 71, and front support plate 51 in sequence outward, and snap the frame buckle 33 into the corresponding slot to lock it; after folding, the volume of the box is 1 / 3 of the unfolded state, saving storage space and facilitating the transportation and storage of empty boxes; after unfolding, the overall structure is stable and the heat preservation performance is not lost.

[0054] The box cover 11, bottom support plate 61, side support plate 41, front support plate 51, and rear support plate 71 are all made of EPS composite board, with an outer layer of ABS plastic and an inner layer filled with high-density insulation cotton to enhance insulation performance.

[0055] In actual use, when the insulated box is in the unfolded state, the various components work together to form a closed box structure, realizing the function of insulated transportation of goods: the bottom support plate 61 serves as the foundation of the entire device, achieving overall support through the bottom feet 21 fixed to the bottom, while also providing an installation benchmark for other components. The two sets of side support plates 41 are hinged to the bottom plate assembly's fixing parts 62, rotating outward to a position perpendicular to the bottom support plate 61. The side plate slots 43 on the top of the side support plates engage with the frame buckles 33 of the fixing assembly, achieving vertical fixation of the side support plates 41 and forming the support structure on both sides of the insulated box. The front support plate 51 rotates outward around the bottom pivot 52, and the front plate slot 53 on the top engages with the corresponding frame buckles 33, forming a closed front structure of the insulated box. The rear support plate 71 rotates outward around the bottom pivot 72, and the rear plate slot 73 on the top engages with the corresponding frame buckles 33, forming a closed rear structure of the insulated box. The upper frame 31 is rotatably connected to the box cover 11 via a hinge. After the side panels, front panel, and rear panel are fixed, the box cover 11 is closed on top of the upper frame 31. The cover buckle 12 is locked in place by cooperating with the frame slot 32 of the upper frame 31 to achieve a seal on the top of the box and ensure the heat preservation effect.

[0056] Stacking function: The top foot 22 of the lid 11 can be engaged with the bottom foot 21 of another insulated box to achieve stable stacking of multiple insulated boxes and improve the utilization of transportation space.

[0057] When storage or empty box transportation is required, release the frame buckles 33 from the front panel slots 53 and 73, and remove the upper frame 31 and lid 11 together. The front support plate 51 and rear support plate 71 are folded inward around their respective bottom pivot points and fitted onto the bottom support plate 61. Release the frame buckles 33 from the side panel slots 43, and the side support plate 41 is folded inward around its bottom hinge point, covering the front support plate 51 and rear support plate 71. Remove the upper frame 31 along with the lid 11, so that the frame buckles 33 are respectively engaged in the side panel slots 42 on the outside of the side support plate 41 and the bottom plate slot 64 of the bottom plate assembly, thus securing the folded state and forming a compact overall structure for easy storage and transportation.

[0058] By switching between the two states, the insulated box can form a sealed and stable insulated space when unfolded to meet the needs of cold chain transportation, and can also significantly reduce its volume when folded to improve the convenience of empty box storage and transportation.

[0059] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A foldable insulated box for cold chain transportation, characterized in that: include: A lid assembly, including a lid (11), for closing the top of the insulated box; The bottom plate assembly, including the bottom support plate (61), is located below the lid (11) and is used to form the bottom structure of the insulated box to support the contents of the box; The side panel assembly includes two sets of side support plates (41), which are symmetrically arranged between the lid (11) and the bottom support plate (61) to form the side structure of the insulated box and provide side support for the items inside the box. The front panel assembly, including a front support plate (51), is disposed between the box cover (11) and the bottom support plate (61) to form the front structure of the insulated box; The rear panel assembly, including a rear support plate (71), is disposed between the box cover (11) and the bottom support plate (61) to form the rear structure of the insulated box; The fixing component includes an upper frame (31) which is rotatably connected to the box cover (11) via a hinge and is used to fix the position of the box cover (11) to the side support plate (41), the front support plate (51), and the rear support plate (71); The connecting components include a foot (21) fixed to the bottom of the base support plate (61) for supporting the entire device.

2. The foldable insulated cold chain transport box according to claim 1, characterized in that: The lid assembly also includes: a lid clip (12) fixed to the lid (11); The fixing components also include: a frame slot (32), which is opened on the upper frame (31) and is used to cooperate with the lid buckle (12) to lock the position of the lid (11) and ensure the sealing effect of the lid (11); The frame buckles (33) are provided in multiple sets and are evenly fixed below the upper frame (31) to connect the lower components and ensure the splicing stability of the entire device.

3. A foldable insulated cold chain transport box according to claim 2, characterized in that: The base plate assembly also includes: Two sets of fasteners (62) are symmetrically arranged and are respectively fixed to both sides of the bottom support plate (61). The bottom of the side support plate (41) is hinged to the fasteners (62) to support the side support plate (41). A fixing plate (63) is fixed to the side support plate (41) and is used to support the rear support plate (71); The base plate slot (64) is provided on the fastener (62). When folded, the frame buckle (33) is partially engaged in the base plate slot (64) to fix the upper frame (31) when folded.

4. A foldable insulated cold chain transport box according to claim 3, characterized in that: The side panel assembly also includes: Side panel slot 1 (42) is opened on the outside of the side support plate (41). When folded, part of the frame buckle (33) is engaged in the side panel slot 1 (42) to fix the upper frame (31) when folded. Side panel slot 2 (43) is opened on the top of the side support plate (41). When unfolded, part of the frame buckle (33) is engaged in the side panel slot 2 (43) to fix the upper frame (31) when unfolded.

5. A foldable insulated cold chain transport box according to claim 4, characterized in that: The front panel assembly also includes: a pivot shaft (52), which is fixedly disposed at the bottom of the front support plate (51) and rotatably disposed at both ends on the bottom support plate (61) to provide a pivot point for the front support plate (51); The front panel slot (53) is opened on the top of the front support plate (51). When unfolded, part of the frame buckle (33) is engaged in the front panel slot (53) to fix the upper frame (31) when unfolded. The rear plate assembly also includes: a second rotating shaft (72), which is fixedly disposed at the bottom of the rear support plate (71) and rotatably disposed at both ends on the bottom support plate (61) to provide a fulcrum for rotation of the rear support plate (71); The rear plate slot (73) is opened on the top of the rear support plate (71). When unfolded, part of the frame buckle (33) is engaged in the rear plate slot (73) to fix the upper frame (31) when unfolded.

6. A foldable insulated cold chain transport box according to claim 5, characterized in that: The connecting component also includes a top foot (22), which is fixed to the top of the box cover (11) and can be snapped into place with the bottom foot (21) at the bottom, so as to cooperate with the bottom foot (21) of the lower insulated box when multiple insulated boxes are stacked to achieve stacking positioning.

7. A foldable insulated cold chain transport box according to claim 6, characterized in that: The insulated box has two states: an unfolded state and a folded state. When the insulated box is in a folded state, the front support plate (51), the rear support plate (71), and the side support plate (41) are folded inward in sequence and stored. The frame buckle (33) is engaged in the side plate slot (42) and the bottom plate slot (64). When the insulated box is in the unfolded state, the side support plate (41), rear support plate (71), and front support plate (51) open outward in sequence, and the frame buckle (33) is engaged in the side plate slot (43), front plate slot (53), and rotating shaft (72) to ensure that the side support plate (41), rear support plate (71), and front support plate (51) are stable when unfolded.

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