A fruit and vegetable fresh-keeping, transporting and storing warehouse

Abstract

The application relates to a fruit and vegetable fresh-keeping and transporting storage bin, which comprises a bin body with an inner cavity, a side door hinged at an open side of the bin body, and multiple storage assemblies arranged in the bin body; the storage assembly comprises a bottom disc arranged on the inner bottom surface of the bin body, multiple groups of vertical rods symmetrically arranged on the top of the bottom disc, multiple groups of material receiving plates arranged at the central positions of the vertical rods and used for containing fruits and vegetables, a guide groove arranged on the side wall of the material receiving plate and slidably connected with the side wall of each vertical rod, and multiple groups of blowing plates arranged on the vertical rods and communicated with the interiors of the vertical rods. In the application, multiple groups of blowing plates are arranged on the vertical rods of each storage assembly, so that each layer of the material receiving plate corresponds to an independent air supply port, airflow can uniformly cover each storage position in the bin, local ventilation dead angles are effectively avoided, ventilation conditions of fruits and vegetables in each area in the bin tend to be consistent, and the overall fresh-keeping effect is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of fruit and vegetable transportation, and in particular to a fruit and vegetable preservation and transportation storage container. Background Technology

[0002] Fresh fruits and vegetables continue to undergo vigorous respiratory metabolism after harvest, constantly releasing respiratory heat and consuming their own nutrients. Combined with the cumulative effect of field heat, this makes them extremely susceptible to spoilage during transportation. For ambient temperature transportation using ordinary trucks (especially for short- and medium-distance delivery), the lack of active refrigeration equipment in the truck compartments exacerbates the problem of accumulated field and respiratory heat after harvest. If ventilation is inadequate, heat and moisture cannot dissipate in time, easily leading to localized temperature increases and excessive humidity, accelerating microbial growth and fruit and vegetable decay.

[0003] Currently, when transporting fruits and vegetables in ordinary trucks, the produce is typically packed into woven bags or plastic crates and stacked inside the truck bed, or layered using simple metal shelves. Ventilation in the truck bed mainly relies on natural ventilation openings on the front or side walls, or the addition of axial fans for auxiliary ventilation. However, this traditional ventilation method has significant drawbacks: firstly, the airflow enters primarily from the overall space of the truck bed, making it difficult to penetrate the densely stacked layers of fruits and vegetables. This results in poor air circulation in the central area of ​​the pile, leading to a large accumulation of heat and ethylene, creating a "heat island" effect. Summary of the Invention

[0004] In view of this, the present invention aims to provide a fruit and vegetable preservation and transportation storage container to solve the problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: This invention proposes a fruit and vegetable preservation and transportation storage container, including a container body with an internal cavity, a side door hinged to an opening on one side of the container body, and a plurality of storage components spaced apart inside the container body. The storage assembly includes a chassis mounted on the bottom surface of the silo body. Multiple sets of uprights are symmetrically fixed to the top of the chassis. Multiple sets of support plates for holding fruits and vegetables are spaced apart at the center of each upright. The side walls of each support plate have guide grooves and are slidably connected to the side walls of each upright through these guide grooves. Each upright is hollow inside, and multiple sets of air-blowing plates communicating with its interior are spaced apart on each upright. Each air-blowing plate has a main air vent facing the support plate. The silo body is equipped with an air-blowing assembly connected to each upright.

[0006] Furthermore, the blower assembly includes an air inlet at the top of the chamber, a mounting cover fixedly disposed inside the chamber at the air inlet, a fan fixedly disposed inside the mounting cover, a connecting pipe symmetrically disposed around the mounting cover, and an extension pipe connected to the end of the connecting pipe. Each of the uprights has a funnel-shaped connecting cover at its top end, and the bottom end of the extension pipe has a corresponding interface to the connecting cover. The side wall of the chamber is provided with an air outlet.

[0007] Furthermore, the main air outlet includes an inclined upper air outlet and a lower air outlet, the ends of which face the material support plate and are inclined in opposite directions.

[0008] Furthermore, a filter plate conforming to the inner contour of the air inlet is fixedly installed inside the air inlet.

[0009] Furthermore, multiple perforations are spaced apart along the length of the upright, and the material support plate is fixedly connected to the perforations by bolts.

[0010] Furthermore, the bottom of the material support plate is evenly provided with multiple bottom holes, and the side wall is provided with side openings.

[0011] Furthermore, the storage assembly also includes a water spraying assembly, which includes a water spraying pipe, a horizontal pipe, a connecting pipe, and nozzles. The end of the water spraying pipe extends into the hopper and is located on one side of the upright. Multiple horizontal pipes are spaced apart on the water spraying pipe, multiple connecting pipes are spaced apart on the horizontal pipes, and multiple nozzles are spaced apart on the connecting pipes. The nozzles are directly facing the material receiving plate. A water storage container is fixedly installed on the top of the silo, and the other end of each of the spray pipes is connected to a water pump inside the water storage container.

[0012] Furthermore, a water channel is provided on one side of the chamber, a drain outlet is provided on the side of the chassis near the water channel, the chassis is set with an inclined surface, and a water outlet connected to the water channel is provided on the side wall of the chamber.

[0013] Furthermore, casters are symmetrically provided on the bottom of the chassis.

[0014] Furthermore, the chassis is slidably connected to the inner bottom surface of the compartment, and the bottom of the compartment is symmetrically provided with first sliding grooves that are adapted to the casters. The bottom of the chassis is fixed with a T-shaped slider between the two casters, and the compartment is provided with a second sliding groove that is adapted to the slider.

[0015] Compared with the prior art, the present invention has the following advantages: In this invention, the uprights are designed as hollow structures, with multiple sets of air-blowing plates spaced apart and communicating with their interiors. Each air-blowing plate has a main air outlet directly facing the material support plate. The air-blowing assembly introduces airflow into the interior of each upright, and then directs it through the main air outlet of the air-blowing plate to the surface of the fruits and vegetables on each layer of the material support plate. This allows air to directly reach the fruit and vegetable storage area, effectively removing heat, moisture, and ethylene gas generated by the respiration of the fruits and vegetables, preventing a heat island effect in the center of the stack, and improving ventilation and heat dissipation conditions for fruits and vegetables under normal temperature transportation conditions.

[0016] By installing multiple sets of air blowing plates on the uprights in each storage component, each layer of the material support plate has an independent air outlet, and the airflow can evenly cover all storage positions in the warehouse, effectively avoiding local ventilation dead spots, making the ventilation conditions of fruits and vegetables in all areas of the warehouse more consistent, and ensuring the overall preservation effect. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 This is a schematic diagram of the storage component structure of the present invention; Figure 4 This is a schematic diagram of the material support plate structure of the present invention; Figure 5 This is a schematic diagram of the blower assembly structure of the present invention; Figure 6 This is a schematic diagram of the fan assembly of the present invention; Figure 7 This is a schematic diagram of the water spray assembly structure of the present invention; Figure 8 This is a schematic diagram of the first and second slide groove structures of the present invention; Figure 9 This is a schematic diagram of the water passage structure of the present invention; Figure 10 This is a schematic diagram of the inclined plane structure of the present invention; Figure 11 This is a schematic diagram of the outlet structure of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Chassis; 101. Casters; 102. Slider; 103. Inclined surface; 104. Drain outlet; 2. Upright pole; 201. Through hole; 202. Connecting cover; 203. Bolt; 3. Blower plate; 301. Upper air outlet; 302. Lower air outlet; 4. Material support plate; 401. Guide groove; 402. Bottom hole; 403. Side opening; 5. Bin body; 501. Side door; 502. First chute; 503. Second chute; 504. Air inlet; 505. Air outlet; 6. Water spray pipe; 601. Horizontal pipe; 602. Connecting pipe; 603. Nozzle; 604. Water storage container; 7. Mounting cover; 701. Fan; 702. Connecting pipe; 703. Extension pipe; 7031. Connecting interface; 704. Filter plate; 8. Water passage trough; 801. Water outlet. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0020] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "back," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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 invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0022] The following will refer to the appendix. Figure 1 To be continued Figure 11 The present invention will be described in detail with reference to the embodiments.

[0023] Overall, a fruit and vegetable preservation and transportation storage container includes a container body 5 with an internal cavity, a side door 501 hinged to an opening on one side of the container body 5, and multiple storage components spaced apart inside the container body 5. The storage components include a chassis 1 set on the bottom surface of the inner body 5. Multiple sets of uprights 2 are symmetrically fixed on the top of the chassis 1. Multiple sets of supporting plates 4 for holding fruits and vegetables are spaced apart at the center of each upright 2. The side wall of the supporting plate 4 is provided with a guide groove 401 and is slidably connected to the side wall of each upright 2 through the guide groove 401. The upright 2 is hollow inside and multiple sets of air blowing plates 3 connected to its interior are spaced apart on the upright 2. The air blowing plates 3 are provided with a main air outlet facing the supporting plate 4. The inner body 5 is provided with an air blowing assembly connected to each upright 2.

[0024] In this embodiment, the uprights 2 are designed as hollow structures, and multiple sets of air-blowing plates 3 connected to their interiors are spaced apart on the uprights 2. Each air-blowing plate 3 has a main air outlet facing the material support plate 4. The air-blowing assembly introduces airflow into the interior of each upright 2, and then directs it through the main air outlet of the air-blowing plate 3 to the surface of the fruits and vegetables on each layer of the material support plate 4. This allows air to directly reach the fruit and vegetable storage area, effectively removing heat, moisture, and ethylene gas generated by the respiration of the fruits and vegetables, preventing the formation of a heat island effect in the center of the stack, and improving ventilation and heat dissipation conditions for fruits and vegetables under normal temperature transportation conditions.

[0025] This invention sets multiple sets of air blowing plates 3 on the uprights 2 in each storage component, so that each layer of material support plate 4 has an independent air outlet. The airflow can evenly cover all storage positions in the warehouse, effectively avoiding local ventilation dead spots, making the ventilation conditions of fruits and vegetables in different areas of the warehouse more consistent, and ensuring the overall preservation effect.

[0026] In addition, the side wall of the material support plate 4 in this invention is provided with a guide groove 401, which is slidably connected to the side wall of each upright 2. Users can flexibly adjust the spacing between each layer of material support plates 4 according to the variety and size of the fruits and vegetables being transported, which avoids large fruits and vegetables from being crushed and damaged due to insufficient layer height, and also avoids small fruits and vegetables from wasting space due to excessive layer height.

[0027] In detail, multiple storage components are spaced apart inside the silo 5, each forming an independent loading unit. The number of storage components can be flexibly increased or decreased according to actual loading needs. The height of each support plate 4 can be adjusted independently, allowing different sizes of fruits and vegetables to be stored simultaneously within the same silo 5, making full use of the internal space of the silo 5 and improving the loading efficiency of a single transport.

[0028] The height adjustment of the support plate 4 on the upright 2 can be achieved in the following ways: Preferably, multiple through holes 201 are provided at intervals along the length of the upright 2, and the support plate 4 is fixedly connected to the through holes 201 by bolts 203. Alternatively, a damping structure (such as a rubber ring) can be provided between the guide groove 401 of the support plate and the upright 2, using damping force to keep the support plate 4 at the adjusted height position.

[0029] As a preferred structure in this embodiment, casters 101 can be symmetrically arranged at the bottom of the chassis 1 to facilitate pushing the storage components into or pulling them out of the compartment 5 as a whole, thus facilitating loading and unloading operations.

[0030] like Figure 5 and Figure 6 As shown, the above-mentioned blowing assembly includes an air inlet 504 opened at the top of the chamber 5, a mounting cover 7 fixedly installed inside the chamber 5 at the air inlet 504, a fan 701 fixedly installed inside the mounting cover 7, a connecting pipe 702 symmetrically connected to the periphery of the mounting cover 7, and an extension pipe 703 connected to the end of the connecting pipe 702. Each upright 2 has a funnel-shaped connecting cover 202 at its top end, and the extension pipe 703 has a corresponding interface 7031 at its bottom end; an air outlet 505 is opened on the side wall of the chamber 5.

[0031] In practice, after the fan 701 is started, it draws outside air into the mounting cover 7 through the air inlet 504 at the top of the chamber 5. The air is then distributed through the mounting cover 7 to each connecting pipe 702, and then conveyed downwards through the extension pipe 703. It enters the interior of each upright 2 through the interface 7031 and the connecting cover 202. The air flows downwards along the hollow interior of the upright 2, and after reaching the positions of each blower plate 3, it is blown out directionally through the main air outlet, directly ventilating the surface of the fruits and vegetables on the receiving plate 4. After flowing over the surface of the fruits and vegetables, the air carries away the heat, moisture, and ethylene gas generated by the respiration of the fruits and vegetables, and finally exits the chamber from the air outlet 505 on the side wall of the chamber 5, completing one complete ventilation cycle.

[0032] As a preferred option, such as Figure 1 As shown, a filter plate 704 conforming to the inner contour of the air inlet 504 is fixedly installed inside the air inlet 504 to prevent large particulate impurities and fibrous debris in the air from entering the installation cover 7, the connecting pipe 702, the extension pipe 703 and the upright 2, thereby extending the service life of the equipment.

[0033] In this embodiment, as Figure 3 As shown, the main air vent includes an inclined upper air vent 301 and a lower air vent 302, with the ends of the upper air vent 301 and the lower air vent 302 facing the material support plate 4 and inclined in opposite directions. This configuration ensures that the airflow from the two air vents covers the surface of the fruits and vegetables on the material support plate 4 at different angles, ensuring that the fruits and vegetables on each layer of the material support plate 4 receive sufficient ventilation.

[0034] In this embodiment, as Figure 4 As shown, the bottom of the material support plate 4 is evenly provided with multiple bottom holes 402, and the side wall is provided with a side opening 403.

[0035] In practice, after the air is blown out from the main air outlet of the air blower plate 3, it can not only cover the fruits and vegetables placed on the upper surface of the support plate 4, but also pass through the bottom hole 402 upward or downward through the support plate 4, so that the air between the two adjacent support plates 4 can be interconnected. At the same time, the side opening 403 allows the airflow to pass through the side of the support plate 4, improving the dehumidification and heat dissipation efficiency.

[0036] In this embodiment, as Figure 2 and Figure 7 As shown, the storage assembly also includes a water spraying assembly, which includes a water spraying pipe 6, a horizontal pipe 601, a connecting pipe 602, and a nozzle 603. The end of the water spraying pipe 6 extends into the silo body 5 and is located on one side of the upright 2. Multiple horizontal pipes 601 are spaced apart on the water spraying pipe 6, and multiple connecting pipes 602 are spaced apart on the horizontal pipes 601. Multiple nozzles 603 are spaced apart on the connecting pipes 602, and the nozzles 603 face the material support plate 4. A water storage container 604 is fixedly installed on the top of the silo body 5, and the other end of each water spraying pipe 6 is connected to a water pump in the water storage container 604.

[0037] The water spray system can replenish the surface moisture of fruits and vegetables in a timely manner, maintain the ambient humidity, effectively delay the dehydration and aging process of fruits and vegetables, and improve the preservation effect under normal temperature transportation conditions.

[0038] In practice, while the nozzle 603 sprays water mist, the airflow from the blower plate 3 further disperses the water mist and spreads it evenly throughout the entire material support plate 4 area. At the same time, the airflow accelerates the evaporation of moisture on the surface of fruits and vegetables, carrying away the latent heat of vaporization, thus achieving the dual effects of cooling and humidification.

[0039] The water spray unit and the air blowing unit can work independently or in conjunction, specifically including the following working modes: Mode 1 (Individual Spraying): The water pump starts and the fan 701 stops. Water is atomized and sprayed from the nozzle 603 through the spray pipe 6, horizontal pipe 601, and connecting pipe 602, directly wetting the surface of fruits and vegetables. This mode is suitable for scenarios where the surface of fruits and vegetables is dry and needs to be quickly hydrated when they are first loaded onto the truck.

[0040] Mode 2 (Simultaneous Spraying and Ventilation): The water pump and fan 701 start simultaneously. While the nozzle 603 sprays water mist, the airflow from the blower plate 3 further disperses the water mist and evenly distributes it throughout the entire material support plate 4 area. Simultaneously, the airflow accelerates the evaporation of moisture from the fruit and vegetable surface, carrying away latent heat of vaporization, achieving a dual effect of cooling and humidification. This mode is the preferred operating mode.

[0041] Mode 3 (Spraying followed by ventilation and drying): The water pump starts spraying for a certain period of time and then stops. Fan 701 continues to run for a while, using airflow to dry or evenly distribute excess moisture on the surface of fruits and vegetables, preventing prolonged moisture retention and mold growth. This mode is suitable for fruits and vegetables with high humidity or those prone to rotting.

[0042] Mode 4 (Independent Ventilation): The water pump is turned off, and fan 701 is started. Only regular ventilation is performed. This mode is suitable for fruits and vegetables with low moisture content that do not require additional humidification, or when the humidity of the transportation environment is already sufficient.

[0043] Users can select any of the above working modes through the control panel according to the characteristics of the fruit and vegetable varieties and the transportation environment conditions. They can also set the spraying interval (e.g., spraying once every 2 hours) and the duration of each spray (e.g., spraying for 1-3 minutes each time) to achieve automated intermittent spraying.

[0044] like Figure 9 As shown, based on the above configuration, a water trough 8 is provided on one side of the tank body 5, a drain outlet 104 is provided on the side of the chassis 1 near the water trough 8, the chassis 1 is provided with an inclined surface 103, and a drain outlet 801 connected to the water trough 8 is provided on the side wall of the tank body 5.

[0045] After the water spray unit operates, excess water mist condenses into droplets and falls onto the material receiving plate 4. The water then drips down through the bottom hole 402 onto the chassis 1. The inclined surface 103 inside the chassis 1 causes the accumulated water to automatically flow towards the water trough 8, converging into the water trough 8 through the drain outlet 104, and finally being discharged outside the chamber from the outlet 801 on the side wall of the chamber body 5. This prevents water from soaking the chassis 1 or overflowing into other areas of the chamber body 5, keeping the interior environment dry and clean.

[0046] In this embodiment, as Figure 8 As shown, the chassis 1 is slidably connected to the inner bottom surface of the compartment 5. The bottom of the compartment 5 is symmetrically provided with a first sliding groove 502 that is adapted to the caster 101. The bottom of the chassis 1 is fixedly provided with a T-shaped slider 102 between the two casters 101. The compartment 5 is provided with a second sliding groove 503 that is adapted to the slider 102.

[0047] The caster 101 and the first slide groove 502 form the first guide, and the T-shaped slider 102 and the second slide groove 503 form the second guide. The dual guide structures work together to ensure that the storage components can accurately reach the predetermined position each time they are pushed into the compartment 5.

[0048] On the one hand, during the process of pushing or pulling the storage component in, the T-shaped slider 102 slides along the second slide groove 503 to precisely guide the movement direction of the storage component, ensuring that the storage component always moves in and out in a straight line and avoids deviation; on the other hand, the T-shaped cross section of the T-shaped slider 102 has a barb anti-detachment function, and the slider 102 is locked in the second slide groove 503 and cannot be pulled out upwards, effectively preventing the storage component from jumping up and down or shifting laterally due to vehicle bumps during transportation, thus improving transportation safety.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fruit and vegetable preservation and transportation storage container, characterized in that: It includes a compartment (5) with an internal cavity, a side door (501) hinged to an opening on one side of the compartment (5), and a plurality of storage components spaced apart inside the compartment (5); The storage assembly includes a chassis (1) set on the bottom surface of the inner wall of the storage unit (5). Multiple sets of uprights (2) are symmetrically fixed on the top of the chassis (1). Multiple sets of support plates (4) for holding fruits and vegetables are spaced apart at the center of each upright (2). The side wall of the support plate (4) is provided with a guide groove (401) and is slidably connected to the side wall of each upright (2) through the guide groove (401). The upright (2) is hollow inside. Multiple sets of air blowing plates (3) connected to the inside of the upright (2) are spaced apart on the upright (2). The air blowing plate (3) is provided with a main air outlet facing the support plate (4). The storage unit (5) is provided with an air blowing assembly connected to each upright (2).

2. The fruit and vegetable preservation and transportation storage container according to claim 1, characterized in that: The blowing assembly includes an air inlet (504) opened on the top of the chamber (5), a mounting cover (7) fixedly installed inside the chamber (5) at the air inlet (504), a fan (701) fixedly installed inside the mounting cover (7), a connecting pipe (702) symmetrically connected to the periphery of the mounting cover (7), and an extension pipe (703) connected to the end of the connecting pipe (702). Each of the uprights (2) has a funnel-shaped connecting cover (202) at its top end, and the extension pipe (703) has a corresponding interface (7031) at its bottom end. The side wall of the chamber (5) is provided with an air outlet (505).

3. The fruit and vegetable preservation and transportation storage container according to claim 1, characterized in that: The main air outlet includes an inclined upper air outlet (301) and a lower air outlet (302), the ends of which are directly opposite to the material support plate (4) and the inclination directions are opposite.

4. The fruit and vegetable preservation and transportation storage container according to claim 2, characterized in that: A filter plate (704) conforming to its inner contour is fixedly installed inside the air inlet (504).

5. A fruit and vegetable preservation and transportation storage container according to claim 1, characterized in that: Multiple perforations (201) are provided at intervals along the length of the upright (2), and the material support plate (4) is fixedly connected to the perforations (201) by bolts (203).

6. The fruit and vegetable preservation and transportation storage container according to claim 1, characterized in that: The bottom of the material support plate (4) is provided with a plurality of bottom holes (402) and the side wall is provided with a side opening (403).

7. A fruit and vegetable preservation and transportation storage container according to claim 6, characterized in that: The storage assembly also includes a water spraying assembly, which includes a water spraying pipe (6), a horizontal pipe (601), a connecting pipe (602), and a nozzle (603). The end of the water spraying pipe (6) extends into the hopper (5) and is located on one side of the upright (2). Multiple horizontal pipes (601) are spaced apart on the water spraying pipe (6). Multiple connecting pipes (602) are spaced apart on the horizontal pipes (601). Multiple nozzles (603) are spaced apart on the connecting pipes (602). The nozzles (603) face the material support plate (4). The top of the silo body (5) is fixedly provided with a water storage container (604), and the other end of each of the spray pipes (6) is connected to the water pump in the water storage container (604).

8. A fruit and vegetable preservation and transportation storage container according to claim 7, characterized in that: A water channel (8) is provided on one side of the chamber (5), and a drain outlet (104) is provided on the side of the chassis (1) near the water channel (8). The chassis (1) is set with an inclined surface (103), and a water outlet (801) connected to the water channel (8) is provided on the side wall of the chamber (5).

9. A fruit and vegetable preservation and transportation storage container according to claim 1, characterized in that: The chassis (1) is symmetrically equipped with casters (101) at the bottom.

10. A fruit and vegetable preservation and transportation storage container according to claim 9, characterized in that: The chassis (1) is slidably connected to the inner bottom surface of the compartment (5). The bottom of the compartment (5) is symmetrically provided with a first sliding groove (502) that is adapted to the caster (101). The bottom of the chassis (1) is fixedly provided with a T-shaped slider (102) between the two casters (101). The compartment (5) is provided with a second sliding groove (503) that is adapted to the slider (102).

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