Composite material evacuation platform and preparation method thereof

Abstract

The present invention provides a composite material evacuation platform and a preparation method thereof, comprising a metal frame and an internal platform plate, the metal frame comprising an inner frame and an outer frame, concrete material is poured between the inner frame and the outer frame to form a frame body, a connecting piece is installed on the frame body, a platform plate is installed on the inner side of the frame body, the connecting piece supports the platform plate, the platform plate is arranged as a flat grid structure, the platform plate comprises a frame, a first transverse rib, a second transverse rib and a vertical rib arranged inside the frame, the first transverse rib is arranged as a cylindrical structure, the extension direction of the first transverse rib is the same as the width direction of the platform plate, the highest point of the first transverse rib is higher than the top of the edge of the platform plate, the second transverse rib is arranged as a wavy structure, the extension direction of the second transverse rib is the same as the first transverse rib, the second transverse rib is arranged between two adjacent first transverse ribs to reduce the gap between the two first transverse ribs, and the vertical rib is arranged to be perpendicular to the first transverse rib.

Description

Technical Field

[0001] The present invention relates to the technical field of rail transportation, and in particular to a composite material evacuation platform and a preparation method thereof. Background Art

[0002] In the design of subway tunnels, evacuation platforms are set on both sides of the track. When the train breaks down or there is a dangerous situation in the tunnel, the passengers are quickly evacuated through the platform, so that the passengers can quickly run out of the tunnel. The current research on evacuation platforms mainly focuses on two aspects: material and structure. From the perspective of material, most of them are made of composite materials. For example, the evacuation platform with a publication number of CN202055858U in the prior art is made of low calorific value flame-retardant composite materials. Although it can meet the performance requirements of moisture resistance, corrosion resistance, electrical insulation, flame retardancy, etc., the evacuation platform in the tunnel is under the influence of the vibration environment of the subway train for a long time. The compressive strength and fatigue resistance of the composite materials in the prior art are poor, resulting in a limited service life of the evacuation platform. From a structural point of view, the evacuation platform with a publication number of CN106089294B in the prior art adopts a flat or grid-like structure. The above structure makes it easy for people to slip and fall when passing on the surface of the platform plate. Therefore, how to design an evacuation platform with good compressive strength and fatigue resistance and can ensure the safe passage of people is an urgent problem to be solved in this field. Summary of the invention

[0003] In view of this, the present invention aims to provide a composite material evacuation platform and a preparation method thereof to solve the problems existing in the prior art.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A composite material evacuation platform, the evacuation platform includes a metal frame and an internal platform plate, the metal frame includes an inner frame and an outer frame, concrete material is poured between the inner frame and the outer frame to form a frame body, a connecting piece is installed on the frame body, a platform plate is installed on the inner side of the frame body, the connecting piece supports the platform plate, the platform plate is set as a flat grid structure, the platform plate includes a frame, a first transverse rib, a second transverse rib and a vertical rib arranged inside the frame, the first transverse rib is set as a cylindrical structure, the extension direction of the first transverse rib is the same as the width direction of the platform plate, the highest point of the first transverse rib is higher than the top of the edge of the platform plate, the second transverse rib is set as a wavy structure, the extension direction of the second transverse rib is the same as the first transverse rib, the second transverse rib is set between two adjacent first transverse ribs to narrow the gap between the two first transverse ribs, and the vertical rib is set to be perpendicular to the first transverse rib.

[0006] Furthermore, the connecting member includes a baffle, a transverse plate, a vertical plate and a support plate. The baffle is configured as a vertical plate-like structure. The top of the baffle is connected to the transverse plate. The transverse plate is perpendicular to the baffle and extends outward. The end of the transverse plate away from the baffle is connected to the vertical plate.

[0007] Furthermore, the vertical plate extends downward, the vertical plate is parallel to the baffle plate, and the height of the vertical plate is greater than the height of the baffle plate. A support plate is arranged at the lower part of the vertical plate, the support plate is parallel to the horizontal plate, and the support plate extends toward the direction of the baffle plate, and a gap is formed between the support plate and the baffle plate.

[0008] Furthermore, the connecting members are provided in plurality and are evenly distributed around the frame body.

[0009] Furthermore, the concrete material between the inner frame and the outer frame is composed according to the following proportions: by weight, 10 to 20 parts of silicate cement, 20 to 40 parts of recycled aggregate, 10 to 20 parts of rubber particles, 5 to 10 parts of reinforcing fiber, and 0.04 to 0.2 of water reducer.

[0010] Furthermore, the recycled aggregate has a particle size of 5-25 mm, and the rubber particles are EPDM rubber particles with a particle size of 2-4 mm.

[0011] Furthermore, the water reducing agent is a polycarboxylic acid water reducing agent with a water reducing rate of 25-50%.

[0012] Furthermore, the wall thickness of the frame body is set to 30-100 mm.

[0013] Furthermore, the platform board adopts a resin concrete composite material, and the resin concrete composite material is composed of the following proportions: in parts by weight, 15-25 epoxy resins, 20-40 parts of glass beads, 10-20 parts of wood ash, 5-10 parts of reinforcing fibers, 5-10 parts of diluents, and 3-8 parts of curing agents.

[0014] Compared with the prior art, the composite material evacuation platform of the present invention has the following advantages:

[0015] The frame is made of concrete to increase the mechanical strength and compressive strength of the evacuation platform; the platform plate of the grid structure is set so that when people pass through the evacuation platform, the first horizontal reinforcement has a reminder and anti-slip function, preventing people from having difficulty locating the moving direction and slipping when passing through the subway tunnel with poor lighting. At the same time, the alternating setting of multiple horizontal and vertical reinforcements ensures that the vertical and horizontal gaps of the grid are small, preventing objects that fall on the platform plate from falling through the gaps.

[0016] The setting of the connecting piece can ensure the connection stability between the frame and the platform plate and prevent the platform plate from collapsing. At the same time, the structure of the connecting piece is convenient for on-site construction and installation.

[0017] The frame and platform plate are made of different materials to ensure the mechanical strength of the evacuation platform while reducing the overall weight of the evacuation platform to facilitate construction and transportation.

[0018] The present invention also provides a method for preparing a composite material evacuation platform, comprising:

[0019] include:

[0020] (1) Make a metal frame according to preset dimensions;

[0021] (2) Prepare concrete materials according to the following proportions:

[0022] In parts by weight, 10-20 parts of Portland cement, 20-40 parts of recycled aggregate, 10-20 parts of rubber particles, 5-10 parts of reinforcing fiber, and 0.04-0.2 parts of water reducing agent;

[0023] The prepared concrete material is poured between the inner frame 11 and the outer frame 12 of the metal frame, and after curing at room temperature for 3 to 5 days, the frame body is formed;

[0024] (3) Prepare the resin concrete composite material according to the following proportions:

[0025] In parts by weight, epoxy resin 15-25, glass beads 20-40, plant ash 10-20, reinforcing fiber 5-10, diluent 5-10, curing agent 3-8, air entraining agent 0.5-1. The prepared resin concrete composite material is poured into the mold of the platform board, and the platform board is obtained after curing and molding;

[0026] (4) Install a plurality of connectors on the four sides of the frame body at preset intervals, and fix the connectors to the frame body, and install the platform plate inside the frame body. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of an axial view of a metal frame according to an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the frame body according to an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the platform plate according to an embodiment of the present invention;

[0030] Figure 4 It is a schematic diagram of the connecting piece structure according to an embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 1-metal frame, 10-frame body, 11-inner frame, 12-outer frame, 2-platform plate, 21-frame, 22-first horizontal rib, 23-second horizontal rib, 24-vertical rib, 3-connector, 31-baffle, 32-horizontal plate, 33-vertical plate, 34-support plate, 35-fixed cavity, 36-notch DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] like Figures 1 to 4 As shown, a composite material evacuation platform and a preparation method thereof, the evacuation platform includes a frame and an internal platform plate, the frame is a metal frame, the metal frame 1 includes an inner frame 11 and an outer frame 12, concrete material is poured between the inner frame 11 and the outer frame 12 to form a frame body 10, so that the evacuation platform forms a frame structure with an outer contour of concrete material, thereby increasing the mechanical strength of the evacuation platform.

[0035] A connecting member 3 is installed on the frame body, and the connecting member 3 includes a fixing cavity 35 and a support plate 34. The connecting member 3 is connected to the frame body 10 through the fixing cavity 35. The support plate 34 extends toward the center of the frame body 10. The platform plate 2 is installed on the inner side of the frame body 10, and the support plate 34 supports the platform plate 2.

[0036] Furthermore, the connecting member 3 includes a baffle 31, a horizontal plate 32, a vertical plate 33 and a support plate 34. The baffle 31 is set as a vertical plate structure. The top of the baffle 31 is connected to the horizontal plate 32. The horizontal plate 32 is perpendicular to the baffle 31 and extends outward. The end of the horizontal plate 32 away from the baffle 31 is connected to the vertical plate 33. The vertical plate 33 extends downward. The vertical plate 33 is parallel to the baffle 31, and the height of the vertical plate 33 is greater than the height of the baffle 31. The support plate 34 is set at the lower part of the vertical plate 33. The support plate 34 is parallel to the horizontal plate 32 and extends in the direction of the baffle 31. A notch 36 is formed between the support plate 34 and the baffle 31. During installation, the connecting member 3 is connected to the frame body 10 through the notch, so that the baffle 31 and the vertical plate 33 are close to the inner and outer sides of the frame body to prevent the connecting member from falling off. The support plate 34 forms a support plane inwardly for supporting the platform plate 2.

[0037] Preferably, the connectors 3 are provided in multiple numbers and evenly distributed around the frame body 10, so as to provide a stable support effect for the platform board 2 and prevent the platform board 2 from tilting and warping. The structural setting of the connector is convenient for installation at the construction site and for adjusting the position of the connector. The connector 3 is integrally formed of metal material.

[0038] The platform plate 2 is configured as a flat grid structure. Specifically, the platform plate 2 includes a frame 21, a first transverse rib 22, a second transverse rib 23, and a vertical rib 24 arranged inside the frame 21. The first transverse rib 22 is configured as a cylindrical structure. The extension direction of the first transverse rib 22 is the same as the width direction of the platform plate 2. The highest point of the first transverse rib 22 is slightly higher than the top of the edge of the platform plate 2. When people pass through the evacuation platform, the first transverse rib 22 has a reminder and anti-slip effect, preventing people from having difficulty locating the moving direction and slipping easily when passing through a subway tunnel with poor lighting.

[0039] The second transverse rib 23 is configured as a wave-shaped structure. The extension direction of the second transverse rib 23 is the same as that of the first transverse rib 22. The second transverse rib 23 is disposed between two adjacent first transverse ribs 22 to reduce the gap between the two first transverse ribs 22 and reduce the number of the first transverse ribs 22, so that the platform plate is lighter as a whole and can ensure sufficient strength.

[0040] Furthermore, the vertical ribs 24 are arranged to be perpendicular to the first transverse ribs 22, and the vertical ribs 24 pass through the first transverse ribs 22 and the second transverse ribs 23, so as to reduce the vertical gap of the platform plate and prevent objects dropped on the platform plate from falling through the gap.

[0041] When the platform plate 2 is installed inside the frame body 10, the direction in which the length of the vertical ribs 24 extends is consistent with the length direction of the evacuation platform.

[0042] In this embodiment, the metal frame 1 is set as a steel wire frame, which is used to pre-shape the frame body before molding and increase the mechanical strength of the frame body after molding. The concrete material between the inner frame 11 and the outer frame 12 is composed of the following proportions: by weight, 10 to 20 parts of silicate cement, 20 to 40 parts of recycled aggregate, 10 to 20 parts of rubber particles, 5 to 10 parts of reinforcing fiber, 0.04 to 0.2 parts of water reducer and other essential components.

[0043] Furthermore, the particle size of the recycled aggregate is 5-25 mm. The rubber particles are EPDM rubber particles with a particle size of 2-4 mm.

[0044] The water reducing agent in the present invention is a polycarboxylic acid water reducing agent with a water reducing rate of 25-50%.

[0045] The wall thickness of the frame body is set to 30-100 mm, preferably, to 60 mm.

[0046] The reinforcing fibers are composed of untwisted rovings made of high-strength glass fiber yarns or basalt fiber yarns or other high-strength, insulating fiber yarns.

[0047] In this embodiment, the internal platform plate adopts a resin concrete composite material, and the resin concrete composite material is composed according to the following proportions: by weight, epoxy resin 15-25, vitrified microspheres 20-40, plant ash 10-20, reinforcing fiber 5-10, diluent 5-10, and curing agent 3-8. Using epoxy resin instead of cement as a gelling material reduces the overall weight of the material and facilitates construction. The epoxy resin reacts with the curing agent to achieve gelation, increase the bonding strength between the components, reduce shrinkage cracks, and have good mechanical properties. Compared with ordinary composite materials for evacuation platforms, it can not only improve mechanical strength, but also has the advantages of light weight and easy construction.

[0048] The diluent is a composition of one or two of the bifunctional active diluents 1,4-butanediol diglycidyl ether and ethylene glycol diglycidyl ether. Compared with the monofunctional diluent, the bifunctional diluent has active groups at both ends, can participate in the curing reaction, has a fast curing rate, can increase the crosslinking density, and improve the strength of the concrete. Compared with the multifunctional diluent, the viscosity is low and has good dilutability.

[0049] The epoxy resin is bisphenol A epoxy resin E51, with an epoxy equivalent of 184-195 g / mol and a density of 1.1-1.3 g / cm 3 .

[0050] The curing agent is any one of phenolic amine, ethylenediamine, dimethylaminodiphenylmethane, and a modified polymer, or a mixture thereof. The composite modified polymer curing agent is a copolymer of tall oil fatty acid and polyalkyltetramine. Preferably, the curing agent is a composition in which the mass ratio of dimethylaminodiphenylmethane to the modified polymer is 1:1. The present application uses a unique composite curing agent, which cooperates with the epoxy resin to greatly improve the compressive strength of the formed resin concrete composite material.

[0051] The rubber particles and reinforcing fibers are the same as those in the above concrete material.

[0052] Vitrified microspheres are hollow, white powder, and have an apparent density of 460kg / m 3 ~480kg / m 3 , the particle size is 400 mesh. Vitrified microsphere powder effectively increases the strength of resin concrete composite materials and improves their aging resistance.

[0053] In this embodiment, the internal platform plate requires multiple grille bars to be assembled together through bonding and connectors. Moisture between different grille bars, i.e. long-term vibration, can easily cause cracks in the contact parts. Therefore, in order to improve the bonding strength between the contact surfaces of two different grille bars, this embodiment applies an epoxy resin bonding layer to the contact parts of the grille bars before assembly to avoid cracks. Specifically, the bonding layer includes the following components A and B in a weight ratio of 10:4, specifically including:

[0054] Component A includes 70-90 parts of bisphenol A epoxy resin, 20-40 parts of bisphenol F epoxy resin, 15-25 parts of diluent, 2-4 parts of KH-550 silane coupling agent and 5-15 parts of filler in parts by weight;

[0055] The B component includes 10 to 15 parts of ketimine curing agent, 30 to 60 parts of polyamide curing agent, and 5 to 10 parts of 2,4,6-tris(dimethylaminomethyl)phenol in parts by weight.

[0056] The diluent in the bonding layer is ethylene glycol diglycidyl ether, and the filler is Sibelco 3000 mesh spherical active silica powder.

[0057] As one embodiment of the present invention, a method for preparing a composite material evacuation platform is also provided, which specifically includes the following process:

[0058] (1) Make a metal frame according to preset dimensions;

[0059] (2) Prepare concrete materials according to the following proportions:

[0060] In parts by weight, there are 10 to 20 parts of Portland cement, 20 to 40 parts of recycled aggregate, 10 to 20 parts of rubber particles, 5 to 10 parts of reinforcing fiber, and 0.04 to 0.2 parts of water reducing agent.

[0061] The prepared concrete material is poured between the inner frame 11 and the outer frame 12 of the metal frame, and after curing at room temperature for 3 to 5 days, the frame body is formed;

[0062] (3) Prepare the resin concrete composite material according to the following proportions:

[0063] In parts by weight, epoxy resin 15-25, glass beads 20-40, plant ash 10-20, reinforcing fiber 5-10, diluent 5-10, curing agent 3-8, air entraining agent 0.5-1. The prepared resin concrete composite material is poured into the mold of the platform board, and the platform board is obtained after curing and molding.

[0064] (4) Install a plurality of connectors on the four sides of the frame body at preset intervals, and fix the connectors to the frame body, and install the platform plate inside the frame body.

[0065] Embodiment 1:

[0066] (1) Make a metal frame according to preset dimensions;

[0067] (2) Prepare concrete materials according to the following proportions:

[0068] In parts by weight, there are 15 parts of Portland cement, 30 parts of recycled aggregate, 15 parts of rubber particles, 8 parts of reinforcing fiber, and 0.1 part of polycarboxylate water reducer.

[0069] The prepared concrete material is poured between the inner frame 11 and the outer frame 12 of the metal frame, and after curing at room temperature for 4 days, the frame body is formed;

[0070] (3) Prepare the resin concrete composite material according to the following proportions:

[0071] In parts by weight, epoxy resin 20, glass beads 30, plant ash 15, reinforcing fiber 7, ethylene glycol diglycidyl ether diluent 7, dimethylamino diphenylmethane type curing agent 5. The prepared resin concrete composite material is poured into the mold of the platform board, and the platform board is obtained after curing and molding.

[0072] Example 2

[0073] The types and proportions of the concrete materials are the same as those in Example 1, except that the curing agent in the resin concrete composite material in (4) is a modified polymer, namely a copolymer of tall oil fatty acid and polyalkyltetramine.

[0074] Example 3

[0075] The type and proportion of the concrete material are the same as those in Example 1, except that the curing agent in the resin concrete composite material in (4) is a composition of dimethylaminodiphenylmethane and a modified polymer in a mass ratio of 1:1.

[0076] Comparative Example 1

[0077] The types and proportions of the concrete materials are the same as those in Example 1, except that no vitrified microspheres and wood ash are added to the resin concrete composite material in (4).

[0078] The resin concrete composite materials of Examples 1 to 4 and Comparative Examples 1 to 3 are all mixed in accordance with the proportions shown in Table 1. The components of the adhesive layer in Examples 1 to 4 are mixed in accordance with the proportions shown in Table 2.

[0079] Table 1 Distribution ratio of each group of resin concrete composite materials

[0080] Epoxy resin Vitrified microspheres plant ash Reinforcement Fiber Thinner Curing agent Example 1 20 30 15 7 7 5 Example 2 20 30 15 7 7 5 Example 3 20 30 15 7 7 5 Comparative Example 1 65 0 0 7 7 5

[0081] According to GB 50728-2011, the evacuation platform in each embodiment and comparative example was measured after 2*10 6 The fatigue stress resistance after the equal amplitude sine wave fatigue load is applied is observed to see if the frame body and the platform plate of the resin concrete composite material are damaged. The compressive strength test of the evacuation platform in each embodiment and comparative example is carried out in accordance with the "Standard for Test Scheme of Mechanical Properties of Ordinary Concrete" GB / T 50081-2019. The specific results are shown in Table 3:

[0082]

[0083] By comparing Example 3 with Examples 1 and 2, it is found that when the curing agent in the resin concrete composite material is set as a composite curing agent, the curing agent cooperates with the epoxy resin, so that the compressive strength of the formed resin concrete composite material is greatly improved.

[0084] By comparing Example 1 with other examples, it is found that the vitrified microspheres and plant ash as lightweight fillers increase the roughness of the surface of the resin concrete composite material, thereby increasing the bonding performance of each component. 6 After the equal-amplitude sine wave fatigue load, there is still no crack in the middle part of the formed resin concrete composite material, and the components are tightly bonded.

[0085] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A composite material evacuation platform, characterized in that: The evacuation platform comprises a metal frame (1) and an internal platform plate (2), wherein the metal frame (1) comprises an inner frame (11) and an outer frame (12), concrete material is poured between the inner frame (11) and the outer frame (12) to form a frame body (10), a connecting piece (3) is installed on the frame body (10), a platform plate (2) is installed on the inner side of the frame body (10), the connecting piece (3) supports the platform plate (2), the platform plate (2) is configured as a flat grid structure, and the platform plate (2) comprises a frame (21), a first transverse rib (22) arranged inside the frame (21), and a second transverse rib ( The first transverse rib (22) is configured as a cylindrical structure, the extension direction of the first transverse rib (22) is the same as the width direction of the platform plate (2), the highest point of the first transverse rib (22) is higher than the top of the edge of the platform plate (2), the second transverse rib (23) is configured as a wavy structure, the extension direction of the second transverse rib (23) is the same as that of the first transverse rib (22), the second transverse rib (23) is arranged between two adjacent first transverse ribs (22) to reduce the gap between the two first transverse ribs (22), and the vertical rib (24) is configured to be perpendicular to the first transverse rib (22).

2. The composite material evacuation platform according to claim 1, characterized in that: The connecting member (3) comprises a baffle (31), a transverse plate (32), a vertical plate (33) and a supporting plate (34); the baffle (31) is arranged as a vertical plate-shaped structure; the top of the baffle (31) is connected to the transverse plate (32); the transverse plate (32) is perpendicular to the baffle (31) and extends outward; and one end of the transverse plate (32) away from the baffle (31) is connected to the vertical plate (33).

3. The composite material evacuation platform according to claim 2, characterized in that: The vertical plate (33) extends downwards, the vertical plate (33) is parallel to the baffle plate (31), and the height of the vertical plate (33) is greater than the height of the baffle plate (31). A support plate (34) is provided at the bottom of the vertical plate (33), the support plate (34) is parallel to the horizontal plate (32), and the support plate (34) extends in the direction of the baffle plate (31), and a gap (36) is formed between the support plate (34) and the baffle plate (31).

4. The composite material evacuation platform according to claim 2, characterized in that: The connecting members (3) are arranged in plurality and are evenly distributed around the frame body (10).

5. The composite material evacuation platform according to claim 1, characterized in that: The concrete material between the inner frame (11) and the outer frame (12) is composed according to the following proportions: in parts by weight, 10 to 20 parts of silicate cement, 20 to 40 parts of recycled aggregate, 10 to 20 parts of rubber particles, 5 to 10 parts of reinforcing fibers, and 0.04 to 0.2 parts of a water reducing agent.

6. The composite material evacuation platform according to claim 5, characterized in that: The recycled aggregate has a particle size of 5-25 mm, and the rubber particles are EPDM rubber particles with a particle size of 2-4 mm.

7. The composite material evacuation platform according to claim 5, characterized in that: The water reducing agent is a polycarboxylic acid water reducing agent with a water reducing rate of 25-50%.

8. The composite material evacuation platform according to claim 1, characterized in that: The wall thickness of the frame body (10) is set to 30-100 mm.

9. The composite material evacuation platform according to claim 1, characterized in that: The platform board adopts a resin concrete composite material, and the resin concrete composite material is composed of the following proportions: in parts by weight, 15-25 parts of epoxy resin, 20-40 parts of glass beads, 10-20 parts of wood ash, 5-10 parts of reinforcing fiber, 5-10 parts of diluent, and 3-8 parts of curing agent.

10. A method for preparing a composite material evacuation platform, characterized in that: include: (1) Make a metal frame according to the preset size; (2) Prepare concrete materials according to the following proportions: In parts by weight, 10-20 parts of Portland cement, 20-40 parts of recycled aggregate, 10-20 parts of rubber particles, 5-10 parts of reinforcing fiber, and 0.04-0.2 parts of water reducing agent; The prepared concrete material is poured between the inner frame (11) and the outer frame (12) of the metal frame, and after curing at room temperature for 3 to 5 days, a frame body is formed; (3) Prepare the resin concrete composite material according to the following proportions: In parts by weight, epoxy resin 15-25, glass beads 20-40, plant ash 10-20, reinforcing fiber 5-10, diluent 5-10, curing agent 3-8, air entraining agent 0.5-1, and pour the prepared resin concrete composite material into the mold of the platform board, and obtain the platform board after curing and molding; (4) Install a plurality of connectors on the four sides of the frame body at preset intervals, fix the connectors to the frame body, and install the platform plate inside the frame body.

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