Multi-layer structure trailer frame and multi-layer structure trailer

Abstract

The utility model discloses a multi-layer structure trailer frame and a multi-layer structure trailer. The multi-layer structure trailer frame comprises a supporting frame and two storage parts. The supporting frame comprises at least three vertical frames, each vertical column is provided with a fixed seat and a sliding seat, and a shear type mechanism is pivoted between the fixed seats and the sliding seats of two adjacent vertical columns on the same side; the first storage part comprises two first storage racks, the outer sides of the first storage racks are pivoted to the two first vertical frames respectively, the pivoting positions are located below the sliding seats, the inner sides of the first storage racks are connected, and the two first storage racks at least can rotate relatively; the second storage part comprises two second storage racks, the outer sides of the second storage racks can rotate relative to the sliding seats of the two first vertical racks, the inner sides of the second storage racks are connected, and the two second storage racks at least can rotate relative to each other. The utility model has the following advantages: a multi-layer structure can be realized, and the structure is simple; linkage can be formed, and the trailer frame is convenient to stretch and retract; the folded trailer frame is low in height, small in occupied space and low in packaging, storage and transportation cost.

Description

Technical Field

[0001] This utility model relates to trailers, and more particularly to a multi-layer trailer frame and a multi-layer trailer. Background Technology

[0002] Traditional trailer frames are single-layer structures, such as US8011686B2 and CN117842156B. Single-layer trailer frames have a small storage capacity and require further improvement. To address this shortcoming, some solutions have been proposed, such as CN215883720U, which discloses a double-layer foldable handcart, including a foldable frame. The frame includes four wheel assemblies, a front wall assembly, a rear wall assembly, two symmetrical side wall assemblies, a push handle assembly, an upper base frame assembly, and a lower base frame assembly. The front and rear ends of the lower base frame assembly are rotatably connected to the lower ends of the front and rear wall assemblies, respectively. The front and rear ends of the upper base frame assembly are rotatably connected to the middle ends of the front and rear wall assemblies, respectively. The upper and lower base frame assemblies are connected by a connecting strip on the same side. Although it introduces the double-layer trailer structure, the linkage mechanism composed of cross tubes, U-shaped crossbars and vertical bars is complex. In addition, the U-shaped crossbars rotate upwards during the folding process, which makes the folded trailer frame relatively high, occupies a lot of space, and has high packaging, transportation and storage costs. Utility Model Content

[0003] This utility model provides a multi-layer structure trailer frame and a multi-layer structure trailer, which overcomes the shortcomings of wheels in the prior art.

[0004] One of the technical solutions adopted by this utility model to solve its technical problem is: a multi-layer structure trailer frame, comprising:

[0005] The support frame includes N uprights arranged along the X direction, where N≥3. Each upright includes two columns fixed at intervals along the Y direction. A fixed seat is fixed at the top of each column, and a sliding seat is slidably mounted on the column. A scissor mechanism is pivotally connected between the fixed seat and the sliding seat of each pair of adjacent uprights on the same side. The N uprights move away from or near each other along the X direction to extend or retract the trailer frame. In the support frame, the two uprights located on the outer side in the X direction are the first uprights, and the remaining uprights are the second uprights.

[0006] The first storage unit includes two first shelves, the outer sides of which are pivotally connected to two first uprights, with the pivoting position below the height of the slide block. The inner sides are connected, and the two first shelves are at least rotatable relative to each other.

[0007] The second storage unit includes two second shelves, the outer sides of which are respectively rotatable relative to the slides of the two first uprights, and the inner sides are connected and the two second shelves are at least rotatable relative to each other.

[0008] In one embodiment: a first limiting mechanism is provided between two first shelves, and a second limiting mechanism is provided between two second shelves; the open trailer rack has the maximum opening angle of the two first shelves at the limiting point of the first limiting mechanism, and the maximum opening angle of the two second shelves at the limiting point of the second limiting mechanism.

[0009] In one embodiment: the second upright is a second upright, and the second upright also includes a support rod fixed between the two second uprights and located below the slide; the inner sides of the two first shelves are pivotally connected together, and the first storage part of the open trailer rack rests against the support rod and the maximum opening angle of the two first shelves is limited by resting against the support rod.

[0010] In one embodiment: the two first shelves are pivotally connected on their inner sides, and at least one of the first shelves has a protrusion on its inner side. The protrusion of one first shelf abuts against the other first shelf, which limits the maximum opening angle between the two adjacent first shelves.

[0011] In one embodiment: the two first shelves are pivotally connected on their inner sides, and the inner sides of the two first shelves have opposing top abutting surfaces. The maximum opening angle of the two first shelves is defined by the top abutting surfaces of the two first shelves abutting against each other.

[0012] In one embodiment: the first upright is a first column, a pivot seat is fixed on the first column, and two cantilever arms are provided on the outer sides of the two first shelves. The cantilever arms are pivoted and pivotally connected to the pivot seat.

[0013] In one embodiment: the second upright is a second upright, and the second upright also includes a positioning seat that slides on the second upright and is located between the fixed seat and the sliding seat; the outer sides of the two second shelves are respectively rotatably connected to the sliding seats of the two first uprights, and the inner sides are connected to the positioning seats. The positioning seats of the opened trailer frame are supported on the sliding seats, and the maximum opening angle of the two second shelves is limited by the positioning seats being supported on the sliding seats.

[0014] In one embodiment: the positioning seat includes a sliding sleeve on the second column and a pivot seat for fixing the sliding sleeve. The pivot seat has pivot positions on both sides, and the inner sides of the two second shelves are rotatably connected to the pivot positions on both sides of the pivot seat.

[0015] In one embodiment: a crossbar is fixed between the pivot seats of the two second columns of the second frame.

[0016] In one embodiment: the second upright is a second upright, and a second support rod is fixed between the slides of the two second uprights; the outer sides of the two second shelves are respectively rotatably connected to the slides of the two first uprights, and the inner sides are pivotally connected together; the second storage part of the open trailer frame rests on the second support rod and the maximum opening angle of the two second shelves is limited by resting on the second support rod.

[0017] In one embodiment: the outer sides of the two second shelves are rotatably connected to the slides of the two first uprights, the inner sides of the two second shelves are pivotally connected together, and at least one second shelf has a second protrusion on its inner side. The second protrusion of one second shelf abuts against the other second shelf, which limits the maximum opening angle of the two adjacent second shelves.

[0018] In one embodiment: the outer sides of the two second shelves are rotatably connected to the slides of the two first uprights, the inner sides of the two second shelves are pivotally connected together, and the inner sides of the two second shelves have opposing second abutting surfaces. The maximum opening angle of the two second shelves is defined by the abutting surfaces of the two second shelves facing each other.

[0019] In one embodiment: the first upright is a first column, and the second shelf has a crossbar on the outside, with both ends of the crossbar pivotally connected to the slides of the two first columns of the first upright.

[0020] In one embodiment: the first upright is a first upright, and a second fixed seat is fixed on the first upright, located between the fixed seat and the slide seat. A clamping fork is connected between the fixed seats of the two first uprights and the second fixed seat. The slide seat of the first upright of the open trailer frame rests against the second fixed seat.

[0021] In one embodiment: the first upright is a first column, and a crossbar located between the fixed seat and the slide is fixed on the two first uprights. The slide of the first upright of the open trailer frame rests against the crossbar.

[0022] In one embodiment: the support frame includes two first uprights and one second upright; N uprights move away from or near each other along the X direction and the first and second shelves rotate downward or upward relative to the first uprights to open or fold the trailer frame.

[0023] The second technical solution adopted by this utility model to solve its technical problem is: a multi-layer structure trailer, including a vehicle body drape, a handle, and a multi-layer structure trailer frame, wherein the first upright is provided with wheels, the handle is connected to the first upright, and the vehicle body drape is connected to the trailer frame.

[0024] In one embodiment: the upper edge of the vehicle body drape is connected to the fixed seat and the vehicle body drape rests against the second storage unit.

[0025] In one embodiment: the first upright is a first column, and a crossbar is fixed at the bottom of the two first columns. One end of the handle is rotatably connected to the crossbar, and the first column is provided with the aforementioned wheels that can be detached and connected.

[0026] Compared with the prior art, this technical solution has the following advantages:

[0027] 1. A scissor mechanism allows N uprights to move away from or near each other along the X direction to open and close the trailer frame; the first storage section includes two first storage racks, which are pivotally connected to the two first uprights on their outer sides and connected and rotatable on their inner sides; the second storage section includes two second storage racks, which can rotate relative to the slides of the two first uprights on their outer sides and are connected and rotatable on their inner sides. Therefore: firstly, a multi-layer structure can be achieved, and the structure is simple; secondly, a linkage can be formed, which facilitates the opening and closing of the trailer frame; thirdly, the height of the folded trailer frame is low, the space occupied is small, and the packaging, storage, and transportation costs are low.

[0028] 2. In the unfolded trailer frame: the maximum opening angle of the two first shelves through the limit of the first limiting mechanism, and the maximum opening angle of the two second shelves through the limit of the second limiting mechanism, improve the stability of the trailer frame when unfolded.

[0029] 3. The inner sides of the two first shelves are pivotally connected. The first storage section of the open trailer frame rests against the support rod, and the maximum opening angle of the two first shelves is limited by resting against the support rod, thereby improving the stability of the supported first storage section and increasing the strength of the second upright. The inner sides of the two second shelves are pivotally connected. The second storage section of the open trailer frame rests against the second support rod, and the maximum opening angle of the two second shelves is limited by resting against the second support rod, thereby improving the stability of the supported second storage section and increasing the strength of the second upright.

[0030] 4. The maximum opening angle between two adjacent first shelves is limited by the extension of one first shelf abutting against another first shelf, or by the second extension of one second shelf abutting against another second shelf, which limits the maximum opening angle between two adjacent second shelves. The structure is simple and the support is stable.

[0031] 5. The maximum opening angle of the two first shelves is limited by the top abutting surfaces of the two first shelves touching each other, or by the second top abutting surfaces of the two second shelves touching each other. The structure is simple.

[0032] 6. A pivot seat is fixed on the first column, and a cantilever is provided on the other side of the first shelf. The cantilever is pivoted and pivotally connected to the pivot seat for easy assembly.

[0033] 7. The outer side of the second shelf is rotatably connected to the slide of the first upright, and the inner side is connected to the positioning seat. The positioning seat of the opened trailer frame rests against the slide. The maximum opening angle of the two second shelves is limited by the positioning seat resting against the slide. Therefore: First, it is convenient for assembly; second, the positioning seat can be supported by the slide, and the second shelf can be supported by the positioning seat, resulting in high support stability; third, the opening and closing of the scissor mechanism and the opening and closing of the second shelf are linked, improving the reliability of the linkage and facilitating the opening and closing of the trailer frame.

[0034] 8. The positioning seat includes a sliding sleeve and a pivot seat. The pivot seat has pivot positions on both sides. The inner sides of the two second shelves can be rotatably connected to the pivot positions on both sides of the pivot seat for easy assembly.

[0035] 9. A crossbar is fixed between the pivot seats of the two second columns of the second frame to improve the reliability of the linkage and enhance the strength of the second frame.

[0036] 10. The second shelf has a crossbar on the outside, with both ends of the crossbar pivotally connected to the slides of the two first columns of the first frame, which facilitates assembly and enhances the strength of the first frame.

[0037] 11. A clamping fork is connected between the fixed base and the second fixed base of the two first uprights. The slide of the first upright of the open trailer frame rests against the second fixed base. Alternatively, a crossbar is fixed between the fixed base and the slide on the two first uprights. The slide of the first upright of the open trailer frame rests against the crossbar, thereby increasing the strength of the first upright and improving the stability of the open trailer frame in the unfolded state. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 This is a three-dimensional schematic diagram of the trailer frame in the open state according to a specific embodiment.

[0040] Figure 2 This is one of the three-dimensional schematic diagrams of the trailer frame folding process in a specific implementation method.

[0041] Figure 3 This is the second three-dimensional schematic diagram of the trailer frame folding process in a specific implementation method.

[0042] Figure 4 This is a three-dimensional schematic diagram of the trailer frame in a folded state according to a specific embodiment.

[0043] Figure 5 This is a three-dimensional exploded view of the trailer frame in a specific embodiment.

[0044] Figure 6 This is a schematic diagram illustrating the principle of the trailer frame being in the open state in a specific implementation method.

[0045] Figure 7 This is a schematic diagram illustrating the principle of the trailer frame folding process in a specific implementation method.

[0046] Figure 8 This is a three-dimensional schematic diagram of the trailer in a specific implementation.

[0047] Figure 9 This is a partially exploded perspective view of the trailer frame in a specific embodiment.

[0048] Figure 10 This is a three-dimensional schematic diagram of the trailer rack handle in a retractable position according to a specific embodiment.

[0049] Figure 11 This is a three-dimensional schematic diagram of the trailer frame handle in a rotating position according to a specific embodiment.

[0050] Figure 12 This is a perspective view of the trailer frame in the open state according to the second specific embodiment.

[0051] Figure 13 This is a three-dimensional schematic diagram of the trailer frame folding process in the second specific embodiment.

[0052] Figure 14 yes Figure 13 Enlarged diagram of point A.

[0053] Figure 15 This is a three-dimensional schematic diagram of the trailer frame in the open state according to the third specific embodiment.

[0054] Figure 16 This is a three-dimensional schematic diagram of the trailer frame folding process in the third specific embodiment.

[0055] Label Explanation:

[0056] First upright 1, first column 11, clamp fork 12, third crossbar 13, wheel 14;

[0057] Second upright 2, second column 21, support rod 22;

[0058] Fixed seat 31, sliding seat 32, positioning seat 33, sliding sleeve 331, second pivot seat 332, second crossbar 333, first pivot seat 34, second fixed seat 35;

[0059] First storage unit 5, first storage shelf 51, cantilever 511;

[0060] Second storage section 6, second shelf 61, first crossbar 611;

[0061] 7. Car body drapes; 8. Handles. Detailed Implementation

[0062] Please refer to Figures 1 to 7 A multi-layer trailer frame includes a support frame, a first storage section 5, and a second storage section 6, which are arranged vertically to each other.

[0063] The support frame includes two first uprights 1 and a second upright 2 located between the two first uprights 1. The first upright 1, the second upright 2, and the other first upright 1 are arranged parallel to each other along the X-direction. Each first upright 1 includes two first columns 11 fixed at a distance in the Y-direction, and each second upright 2 includes two second columns 21 fixed at a distance in the Y-direction. This specific embodiment uses three uprights as an example (two first uprights and one second upright), but it is not limited to this; multiple second uprights can be provided as needed (e.g., two second uprights in the second specific embodiment). The tops of both the first upright 11 and the second upright 21 are fixed with bases 31, and both the first upright 11 and the second upright 21 are slidably provided with slides 32. The bases 31 and slides 32 of the first upright 11 have two first pivot positions arranged at right angles, and the bases 31 and slides 32 of the second upright 21 have two first pivot positions arranged symmetrically from left to right. A positioning seat 33 located between the bases 31 and slides 32 is also slidably provided on the second upright 21. The second support frame 2 also includes a support rod 22 fixed to the bottom end of the two second columns 21 and located below the slide 32.

[0064] A scissor mechanism 4 is pivotally connected between the first pivot position of the base 31 of the first upright 11 and the second upright 21 on the same side, and the first pivot position of the slide 32. The positioning seat 33 of the second upright 2, which can move away from or approach the trailer frame (open trailer frame) in the X direction to keep it in the open state, is supported by the slide 32. The scissor mechanism 4 includes one scissor unit or multiple scissor units pivotally connected together in series (adjacent upper and lower ends are pivotally connected together). The scissor unit includes two connecting rods pivotally connected together in the middle.

[0065] The first storage section 5 includes two first storage racks 51. The outer sides of the two first storage racks 51 are pivotally connected to the two first uprights 1, and the pivot position is located below the slide 32. The first storage section 5 constitutes the lower storage layer. The inner sides of the two first storage racks 51 are rotatably connected together or connected together through a connecting seat (such as the inner sides of the two first storage racks being connected to both sides of the connecting seat). The first storage section 51 of the trailer frame in the open state rests against the support rod 22. The first storage section 5 is supported by the structure of the inner sides of the two first storage racks 51 being connected together or / and resting against the support rod 22. The first storage rack resting against the support rod 22 also limits the two first storage racks to the maximum opening angle. Other structures may also be adopted as needed. In the specific structure: a first pivot seat 34 is fixed on the bottom of the two first columns 11 of the first frame 1. The first pivot seat 34 is provided with a second pivot position. Two cantilever arms 511 are provided on the other side of the two first shelves 51. The cantilever arms 511 are provided with a pivot, and the pivot is pivotally connected to the second pivot position of the first pivot seat 34.

[0066] The second storage section 6 includes two second shelves 61. The outer sides of the two second shelves 61 are rotatably connected to the slides 32 of the two first uprights 1. The inner sides of the two second shelves 61 are rotatably connected to the positioning seats 33 of the two second columns 21 of the second uprights 2. The positioning seats 33 of the second uprights 2 of the trailer frame in the open state are supported on the slides 32 to maintain the open state. The second storage section 6 is supported on the slides 32. The second storage section 6 constitutes the upper storage layer. The maximum opening angle of the two second shelves is limited by the positioning seats 33 being supported on the slides 32. In the specific structure: the second shelf 61 has a first crossbar 611 on one side, and the two ends of the first crossbar 611 are respectively pivotally connected to the slide seats 32 of the two first columns 11 of the first stand 1; the positioning seat 33 includes a slide sleeve 331 that slides on the second column 21 and a second pivot seat 332 that is fixed to the slide sleeve 331. The second pivot seat 332 has a third pivot position on both sides. The second shelf 61 has a second cantilever on the other side. The second cantilever on the other side of the two second shelves 61 can be rotatably connected to the third pivot positions on both sides of the second pivot seat 332 to facilitate assembly and improve support strength. The second crossbar 333 is fixed between the second pivot seats 332 of the two second columns 21 of the second stand 2 to improve support strength and improve the strength of the second stand.

[0067] In this embodiment: a second fixed seat 35 is also fixed on the first column 11 of the first upright frame 1, located between the fixed seat 31 and the slide seat 32. A clamping fork 12 is connected between the fixed seat 31 and the second fixed seat 35 of the two first upright columns 11. The slide seat 32 of the first upright column of the trailer frame in the open state rests against the second fixed seat 35 to enhance the strength of the first upright frame and improve the stability when in the open state.

[0068] Opening the trailer frame: The first upright 1 and the second upright 2 move away from each other (pull apart in the length direction), the scissor mechanism 4 opens, the two first shelves 51 of the first storage section 5 open (the first shelves 51 rotate downward relative to the first upright), the two second shelves 61 of the second storage section 6 open, until the slide 32 of the first column 11 slides upward to the second fixed seat 35, the first storage section 5 rests against the support rod 22, and the positioning seat 33 rests against the slide 32 of the second column 21, so that the trailer frame is in the open state.

[0069] Folding trailer frame: Lift the middle of the first storage section 5 and the second storage section 6 upward (the first storage rack 51 rotates upward relative to the first upright), and under the combined action of the scissor mechanism 4 on both sides, the slide 32 slides downward, and the first upright 1 and the second upright 2 approach each other (the trailer frame folds in the length direction) until the trailer frame is in the folded state.

[0070] In another embodiment: please refer to Figures 8 to 11A multi-layered trailer includes a body cover 7, a handle 8, and the aforementioned trailer frame. The upper edge of the body cover 7 is connected to a fixed base 31, and its bottom surface rests against a second storage section 6. If the body cover 7 is a container formed by four sides and a bottom surface, the upper edges of the four sides (upper edge) are fixedly connected to the fixed base 31, and the bottom surface is supported on the second storage section 6. A third crossbar 13 is fixedly mounted at the bottom end of the two first uprights 11 of the first support frame 1. A first pivot seat 34 is located on the third crossbar 13. One end of the handle 8 is rotatably connected to the third crossbar 13. The handle may be telescopic. Wheels 14 are detachably connected to the lower part of the first upright 11.

[0071] The second specific implementation method differs from the previous specific implementation method in that: please refer to... Figures 12 to 14 The second storage section 6 is supported in a different way. Specifically, the two second storage shelves 61 are pivotally connected on their inner sides. One second storage shelf 61 has a second protrusion 612 on its inner side. The other second storage shelf 61 is fixed with a limiting seat. The limiting seat has an upward-facing support groove 613. When the second protrusion 612 is supported against the support groove 613 of the other second storage shelf 61, the maximum opening angle of the two second storage shelves is limited so as to support the second storage section 6 in the open state.

[0072] The third specific implementation method differs from the second specific implementation method in that: please refer to... Figure 15 , Figure 16 The support frame includes four uprights, including two first uprights 1 and two second uprights 2 located between the first uprights 1. The slides and fixed seats of adjacent first uprights and second uprights are connected by scissor mechanisms 4, and the slides and fixed seats of adjacent second uprights are connected by scissor mechanisms 4.

[0073] The above description is only a preferred embodiment of the present utility model, and therefore cannot be used to limit the scope of the present utility model. All equivalent changes and modifications made in accordance with the scope of the present utility model patent and the contents of the specification should still fall within the scope of the present utility model.

Claims

1. A multi-layer trailer frame, characterized in that: include: The support frame includes N uprights arranged along the X direction, where N≥3. Each upright includes two columns fixed at intervals along the Y direction. A fixed seat is fixed at the top of each column, and a sliding seat is slidably mounted on the column. A scissor mechanism is pivotally connected between the fixed seat and the sliding seat of each pair of adjacent uprights on the same side. The N uprights move away from or near each other along the X direction to extend or retract the trailer frame. In the support frame, the two uprights located on the outer side in the X direction are the first uprights, and the remaining uprights are the second uprights. The first storage unit includes two first shelves, the outer sides of which are pivotally connected to two first uprights, with the pivoting position below the height of the slide block. The inner sides are connected, and the two first shelves are at least rotatable relative to each other. The second storage unit includes two second shelves, the outer sides of which are respectively rotatable relative to the slides of the two first uprights, and the inner sides are connected and the two second shelves are at least rotatable relative to each other.

2. The multi-layer trailer frame according to claim 1, characterized in that: A first limiting mechanism is provided between the two first shelves, and a second limiting mechanism is provided between the two second shelves. The opening of the trailer frame is defined by the maximum opening angle of the two first shelves at the limiting point of the first limiting mechanism, and the maximum opening angle of the two second shelves at the limiting point of the second limiting mechanism.

3. The multi-layer trailer frame according to claim 1, characterized in that: The second upright is a second upright, and the second upright also includes a support rod fixed between the two second uprights and located below the slide; the inner sides of the two first shelves are pivotally connected together, and the first storage part of the open trailer frame rests against the support rod and the maximum opening angle of the two first shelves is limited by resting against the support rod.

4. A multi-layer trailer frame according to claim 1, characterized in that: The two first shelves are pivotally connected on their inner sides, and at least one of the first shelves has a protrusion on its inner side. The protrusion of one first shelf supports the other first shelf, which limits the maximum opening angle between the two adjacent first shelves.

5. A multi-layer trailer frame according to claim 1, characterized in that: The two first shelves are pivotally connected on their inner sides, and the inner sides of the two first shelves have opposing top abutting surfaces. The maximum opening angle of the two first shelves is defined by the top abutting surfaces of the two first shelves abutting against each other.

6. A multi-layer trailer frame according to claim 3, 4, or 5, characterized in that: The first upright is a column, and a pivot seat is fixed on the first upright. Two cantilever arms are provided on the outer sides of the two first shelves. The cantilever arms are pivoted and pivotally connected to the pivot seat.

7. A multi-layer trailer frame according to claim 1, characterized in that: The second upright is a second upright, and the second upright also includes a positioning seat that slides on the second upright and is located between the fixed seat and the sliding seat; the outer sides of the two second shelves are rotatably connected to the sliding seats of the two first uprights, and the inner sides are connected to the positioning seats. The positioning seats of the opened trailer frame rest against the sliding seats, and the maximum opening angle of the two second shelves is limited by the positioning seats resting against the sliding seats.

8. A multi-layer trailer frame according to claim 7, characterized in that: The positioning seat includes a sliding sleeve on the second column and a pivot seat for fixing the sliding sleeve. The pivot seat has pivot positions on both sides, and the inner sides of the two second shelves are rotatably connected to the pivot positions on both sides of the pivot seat.

9. A multi-layer trailer frame according to claim 7, characterized in that: A crossbar is fixed between the pivot seats of the two second columns of the second frame.

10. A multi-layer trailer frame according to claim 1, characterized in that: The second upright has a column, and a second support rod is fixed between the slides of the two second uprights; the outer sides of the two second shelves are rotatably connected to the slides of the two first uprights, and the inner sides are pivotally connected together; the second storage part of the open trailer frame rests on the second support rod and the maximum opening angle of the two second shelves is limited by resting on the second support rod.

11. A multi-layer trailer frame according to claim 1, characterized in that: The outer sides of the two second shelves are rotatably connected to the slides of the two first uprights, and the inner sides of the two second shelves are pivotally connected together. At least one of the second shelves has a second protrusion on its inner side. The second protrusion of one second shelf supports the other second shelf and limits the maximum opening angle between the two adjacent second shelves.

12. A multi-layer trailer frame according to claim 1, characterized in that: The outer sides of the two second shelves are rotatably connected to the sliding seats of the two first uprights, and the inner sides of the two second shelves are pivotally connected together. The inner sides of the two second shelves have opposing second abutting surfaces, and the maximum opening angle of the two second shelves is limited by the abutting surfaces of the two second shelves facing each other.

13. A multi-layer trailer frame according to any one of claims 7 to 12, characterized in that: The first upright is a first upright, and the second shelf has a crossbar on the outside, with both ends of the crossbar pivotally connected to the slides of the two first uprights of the first upright.

14. A multi-layer trailer frame according to claim 1, characterized in that: The first upright has a first upright, and a second fixed seat is fixed on the first upright between the fixed seat and the slide seat. A clamping fork is connected between the fixed seats of the two first uprights and the second fixed seat. The slide seat of the first upright of the open trailer frame rests against the second fixed seat.

15. A multi-layer trailer frame according to claim 1, characterized in that: The first upright is the first upright, and a crossbar is fixed on the two first uprights between the fixed seat and the sliding seat. The sliding seat of the first upright of the open trailer frame rests against the crossbar.

16. A multi-layer trailer frame according to claim 1, characterized in that: The support frame includes two first uprights and one second upright; N uprights move away from or near each other along the X direction, and the first and second shelves rotate downward or upward relative to the first uprights to open or fold the trailer frame.

17. A multi-layer structure trailer, characterized in that: The vehicle includes a body panel, handles, and a multi-layered trailer frame according to claim 1, wherein the first upright is provided with wheels, the handles are connected to the first upright, and the body panel is connected to the trailer frame.

18. A multi-layer structure trailer according to claim 17, characterized in that: The upper edge of the vehicle body fabric is connected to the fixed seat and the vehicle body fabric is supported on the second storage part.

19. A multi-layer structure trailer according to claim 17, characterized in that: The first upright has a column, and two first uprights are fixed with crossbars at their bottom ends. One end of the handle is rotatably connected to the crossbar. The first upright is equipped with the aforementioned wheels that can be detached and connected.

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