Hollow building panel

Abstract

The hollow building panel provided by the utility model comprises a plurality of unit components which are arranged in sequence, and each unit component can comprise a first panel part, a second panel part and a core plate; the two ends of the core plate are connected with the inner end of the first panel part and the inner end of the second panel part through the first connecting folded edge part and the second connecting folded edge part respectively. The outer end of the first panel part and the outer end of the second panel part respectively form a first sewing turnup and a second sewing turnup which are bent towards the inner side and the inner end; the first connecting folded edge part and the second connecting folded edge part of the unit component can respectively comprise a first bending composite section and a second bending composite section which are inclined towards the outer side; and the first bending composite section and the second bending composite section can respectively correspond to the first sewing turnup and the second sewing turnup, so that the unit components can be conveniently sewn and fixed. The hollow building panel can be conveniently formed by matching the first bending composite section in the first unit component with the first sewing flanging of the second unit component.

Description

Technical Field

[0001] The utility model relates to a building panel technology, in particular to a hollow building panel. Background Art

[0002] Currently, forming building panels using composite materials has become one of the important development trends. Existing hollow building panels usually have panels on two surfaces and connecting support plates between the two panels. Since the connecting support plates are located between the two panels and are relatively fixed, building panels with suitable strength and stiffness can be formed. At the same time, due to their hollow structure, the weight of the hollow building panels can be significantly reduced.

[0003] Hollow building panels are usually formed by connecting multiple unit components. By changing the number of unit components, the hollow building panels can have a suitable area. The shape of the structure of the unit components not only affects the mechanical properties of the hollow building panels but also relates to the connection and fixing methods between the unit components, thereby affecting the production efficiency of the hollow building panels.

[0004] Therefore, how to improve the production efficiency of hollow building panels while ensuring their mechanical properties is an important technical problem that needs to be solved by those skilled in the art. Summary of the Utility Model

[0005] For this reason, the utility model provides a hollow building panel with high efficiency in forming the hollow building panel, so as to improve the production efficiency of the hollow building panel while ensuring its mechanical properties.

[0006] The hollow building panel provided by the utility model includes a plurality of unit components arranged in sequence. It is characterized in that the unit components are formed by bending a complete sheet of material and may include a first panel part, a second panel part, and a core board;

[0007] Both ends of the core board are respectively connected to the inner ends of the first panel part and the second panel part through a first connecting folding part and a second connecting folding part; the outer ends of the first panel part and the second panel part respectively form a first sewing flanging and a second sewing flanging that are bent inward and toward the inner end;

[0008] The first connecting folding part and the second connecting folding part of the unit component may respectively include a first bending composite section and a first bending composite section that are inclined outward; and the first bending composite section and the first bending composite section may respectively correspond to the first sewing flanging and the second sewing flanging to facilitate the sewing and fixing between the unit components.

[0009] By bending the above unit components formed integrally, they can be sequentially arranged in the cross-sectional direction, and the first bending composite section in the first unit component can be inserted between the first sewing flange and the first panel part of the second unit component; the second bending composite section in the first unit component can be inserted between the second sewing flange and the second panel part of the second unit component; and the first bending composite section of the first unit component is kept in close contact and fixed with the first sewing flange and the first panel part of the second unit component, and the second bending composite section in the first unit component is kept in close contact and fixed with the second sewing flange and the second panel part of the second unit component. Furthermore, adjacent unit components can be sewn and kept fixed, and several unit components can be sequentially connected and fixed in the same way to form a hollow building panel with appropriate dimensions. By the cooperation of the first bending composite section in the first unit component and the first sewing flange of the second unit component, a hollow building panel can be conveniently formed; at the same time, between the unit components, through the sewing and fixing of the first bending composite section in the first unit component and the first sewing flange of the second unit component, and combined with the core board connecting the first panel part and the second panel part, while ensuring the mechanical properties of the hollow building panel, the production efficiency of the hollow building panel can be improved.

[0010] In a further optional technical solution, the extension directions of the first panel part and the second panel part are kept parallel. In this way, before and after the hollow building panel is sewn, the relative positions of the first panel part and the second panel part with respect to the core board are the same, which is convenient for reducing the stress of the hollow building panel after sewing, reducing the deformation of the hollow building panel, and improving the stability of the mechanical properties of the hollow building panel.

[0011] In a further optional technical solution, when forming the unit component, the extension direction of the core board is perpendicular to the extension direction of the first panel part. In this way, the supporting role of the core board 30 can be fully exerted, and the rigidity and stability in the thickness direction of the hollow building panel can be ensured.

[0012] In a further reliable technical solution, when forming the unit component, the first panel part and the second panel part extend obliquely to both sides respectively. In this way, when sewing the unit components, the tapered structure formed by the first panel part and the second panel part can be utilized to facilitate the joining between the unit components, and further provide convenience for sewing and fixing, which can improve the production efficiency of the hollow building panel and reduce the cost of the hollow building panel.

[0013] In a further preferred technical solution, the first connecting folded edge portion and the second connecting folded edge portion further respectively include a first folding receiving concave portion and a second folding receiving concave portion; the first folding receiving concave portion is connected between the first bending composite section and the first panel portion, and the second folding receiving concave portion is connected between the second bending composite section and the second panel portion; the first folding receiving concave portion and the second folding receiving concave portion respectively form a first folding receiving groove and a second folding receiving groove, and accommodate the stitched folding edge; more preferably, the depths of the first folding receiving groove and the second folding receiving groove are both not less than 4 times the thickness of the unit member plate. In this way, the stitched folding edge can be located within the sides of the first panel portion and the second panel portion, thereby ensuring the flatness of the surface of the hollow building panel and improving the service performance of the hollow building panel.

[0014] In an alternative technical solution, the first panel portion and the second panel portion are symmetrically arranged. This can ensure the flatness of the hollow building panel and avoid skew.

[0015] In an alternative technical solution, the cross-sectional width of the first panel portion is 1.3 to 1.9 times the cross-sectional width ratio of the core board. This can ensure the supporting effect of the panel portion of the core board, and thus ensure the strength of the hollow building panel. At the same time, the cross-sectional widths of the first stitched edge and the second stitched edge are both greater than one-tenth of the cross-sectional width of the first panel portion, which can ensure a suitable connection size between the unit members, and thus ensure the reliability of the connection between the unit members in the hollow building panel.

[0016] In a further preferred technical solution, the first stitched edge in the first unit member is inserted between the first bending composite section and the first folding receiving concave portion of the second unit member; the second stitched edge in the first unit member is inserted between the second bending composite section and the second folding receiving concave portion of the second unit member; and the first stitched edge in the first unit member is kept in close contact and fixed with the first bending composite section and the first folding receiving concave portion of the second unit member; the second stitched edge in the first unit member is kept in close contact and fixed with the second bending composite section and the second folding receiving concave portion of the second unit member. This can improve the reliability of the stitched connection and fixation between the unit members and improve the rigidity of the hollow building panel.

[0017] In a further technical solution, the hollow building panel further includes an edge unit member and a plugging member; the edge unit member is formed by bending a complete sheet, and includes a first edge panel part, a second edge panel part and an edge core board; both ends of the edge core board are respectively connected to the inner ends of the first edge panel part and the second edge panel part through a first edge bending composite section and a second edge bending composite section; the first edge bending composite section in the edge unit member is inserted between the first stitching flange of the outermost unit member and the first panel part; the second edge bending composite section in the edge unit member is inserted between the second stitching flange of the outermost unit member and the second panel part; and the first edge bending composite section of the edge unit member is kept in close contact and fixed with the first stitching flange and the first panel part of the outermost unit member, and the second edge bending composite section of the edge unit member is kept in close contact and fixed with the second stitching flange and the second panel part of the outermost unit member;

[0018] Both sides of the plugging member are respectively connected to the first edge panel part and the second edge panel part to plug the opening on the outer side of the edge unit member. The opening of the hollow building panel can be plugged through the edge unit member and the plugging member, which on the one hand ensures the strength and rigidity of the hollow building panel, and on the other hand improves the safety of the hollow building panel.

[0019] In an alternative technical solution, the first edge panel part and the second edge panel part can be extended in parallel, and the outer ends of the first edge panel part and the second edge panel part can be kept flush with the outer surface of the plugging member to ensure the flatness of the overall contour of the hollow building panel.

[0020] In a preferred technical solution, right-angle flanges are respectively formed on both sides of the plugging member, and the two right-angle flanges are respectively attached to and fixed with the inner surfaces of the first edge panel part and the second edge panel part. This can improve the strength and rigidity of the hollow building panel. Description of the Drawings

[0021] Referring to the drawings that describe the specific structure of the specific implementation manner of the present invention, the present invention can be more conveniently further described, wherein corresponding parts are used to replace the whole. It should be noted that: other arrangements of the present invention are possible, so the particularity of the drawings should not be understood as being able to replace the general description of the present invention.

[0022] Figure 1 This is a sectional structure diagram of the unit member of a hollow building panel provided by the present invention.

[0023] Figure 2 For two adjacent Figure 1 The corresponding diagram of the unit members shown.

[0024] Figure 3 Figure 1 shows the interleaved state of the bending composite sections and the stitching flanges of two adjacent unit members.

[0025] Figure 4 Figure 2 shows the structure of the fitting state of the bending composite sections and the stitching flanges of two adjacent unit members.

[0026] Figure 5 is Figure 4 the enlarged structure diagram of part A in Figure 1.

[0027] Figure 6 Figure 3 is the overall screenshot of the hollow building panel provided by the present utility model.

[0028] Figure 7 Figure 4 is the side view of the hollow building panel provided by the present utility model.

[0029] Figure 8 Figure 5 is the cross-sectional structure diagram of the hollow building panel provided by the present utility model, showing the edge sealing structure. Detailed implementation manners

[0030] The following describes the detailed implementation manners provided by the present utility model. Those skilled in the art can understand that in this patent, the unit member is a long strip member, and its main improved structure is reflected in the cross-sectional structure. Therefore, for the convenience of description and for easy understanding, the orientation terms in this document are mainly determined based on the cross-sectional view shown in the corresponding drawings; similarly, for the convenience of description and for easy understanding, and at the same time to save space, when describing the unit member of the hollow building panel in this part, the hollow building panel is also described.

[0031] Please refer to Figure 1 , [[ID=ID=34]] Figure 1 Figure 6 is the cross-sectional structure diagram of the unit member of a hollow building panel provided by the present utility model. The unit member is a long strip, and is formed by bending a plate with a predetermined length and width in a suitable manner. In the embodiment, the plate is a galvanized steel plate with a thickness of 2 mm. The unique feature of the unit member lies in the cross-sectional structure, which includes a first panel part 10, a second panel part 20, and a core plate 30.

[0032] Both ends of the core plate 30 are respectively connected to the inner ends of the first panel part 10 and the second panel part 20 through a first connecting folded edge part 40 and a second connecting folded edge part 50. The connecting folded edge part is formed by laminating plates. The first connecting folded edge part 40 and the second connecting folded edge part 50 respectively include a first bending composite section 41 and a first bending composite section 51 that are inclined outward.

[0033] The outer ends of the first panel part 10 and the second panel part 20 respectively form a first stitching flange 11 and a second stitching flange 21 that are bent inward and toward the inner end, forming a hook shape.

[0034] The first bent composite section 41 and the first bent composite section 51 respectively correspond to the first stitched flange 11 and the second stitched flange 21, so that the unit components overlap each other, thereby facilitating the stitching and fixing between the unit components.

[0035] Please refer to Figure 2 and Figure 3 , Figure 2 are two adjacent Figure 1 figures corresponding to the unit components shown, Figure 3 which schematically shows the staggered state of the bent composite sections and the stitched flanges of two adjacent unit components. It can be determined that through the above unit components formed by integral bending, they can be sequentially arranged in the cross-sectional direction, and the first bent composite section 41 in the first unit component can be inserted between the first stitched flange 11 and the first panel part 10 of the second unit component; the second bent composite section 51 in the first unit component can be inserted between the second stitched flange 21 and the second panel part 20 of the second unit component.

[0036] Refer again to Figure 4 and Figure 5 , Figure 4 which schematically shows the structure of the fitting state of the bent composite sections and the stitched flanges of two adjacent unit components, Figure 5 is Figure 4 the enlarged structure diagram of part A in

[0037] The first bent composite section 41 of the first unit component is kept in fitting and fixing with the first stitched flange 11 and the first panel part 10 of the second unit component, and the second bent composite section 51 in the first unit component is kept in fitting and fixing with the second stitched flange 21 and the second panel part 20 of the second unit component, thereby enabling adjacent unit components to be stitched and kept fixed. A number of unit components are sequentially connected and fixed in the same way, and a hollow building panel with an appropriate size can be formed. Through the cooperation of the first bent composite section 41 in the first unit component and the first stitched flange 11 of the second unit component, a hollow building panel can be conveniently formed; at the same time, between the unit components, through the stitching and fixing of the first bent composite section 41 in the first unit component and the first stitched flange 11 of the second unit component, and combined with the core board 30 connecting the first panel part 10 and the second panel part 20, the mechanical properties of the hollow building panel can be ensured while improving the production efficiency of the hollow building panel.In this embodiment, when forming the bent unit member, the extension directions of the first panel portion 10 and the second panel portion 20 can be kept parallel. Before stitching adjacent unit members, the first panel portion 10 and the second panel portion 20 are first opened outward by a suitable device to form a tapered structure, so that adjacent unit members can be staggered. This can make the relative positions of the first panel portion 10 and the second panel portion 20 and the core board 30 the same before and after the hollow building panel is formed by stitching, reduce the stress of the hollow building panel after stitching, reduce the deformation of the hollow building panel, and improve the stability of the mechanical properties of the hollow building panel. Of course, when forming the bent unit member, the first panel portion 10 and the second panel portion 20 can also be inclined and extended to both sides respectively. In this way, when stitching the unit members, the tapered structure formed by the first panel portion 10 and the second panel portion 20 can be utilized to facilitate the joining between the unit members, thereby facilitating stitching and fixing, improving the manufacturing efficiency of the hollow building panel, and reducing the cost of the hollow building panel.

[0038] In this embodiment, the extension direction of the core board 30 is perpendicular to the extension direction of the first panel portion 10. This can give full play to the supporting role of the core board 30 and ensure the rigidity and stability of the hollow building panel in the thickness direction. According to actual needs, the extension direction of the core board 30 can also be set to be relatively inclined to the extension direction of the first panel portion 10 to have higher strength or stiffness in certain specific directions.

[0039] Please refer to Figures 2 to 5 , in this embodiment, the first connecting folded edge portion 40 and the second connecting folded edge portion 50 further respectively include a first folding receiving concave portion 42 and a second folding receiving concave portion 52; the first folding receiving concave portion 42 is connected between the first bending composite section 41 and the first panel portion 10, and the second folding receiving concave portion 52 is connected between the second bending composite section 51 and the second panel portion 20; the first folding receiving concave portion 42 and the second folding receiving concave portion 52 respectively form a first folding receiving groove and a second folding receiving groove to receive the stitched folded edge; preferably, the depths of the first folding receiving groove and the second folding receiving groove are both not less than 4 times the thickness of the unit member plate. This can place the stitched folded edge inside the sides of the first panel portion 10 and the second panel portion 20, thereby ensuring the flatness of the surface of the hollow building panel and improving the service performance of the hollow building panel.

[0040] As described above, arranging and stitching and fixing the above unit members in sequence can form the hollow building panel provided by the present invention. Please refer to Figure 6 and Figure 7 , Figure 6 is an overall screenshot of the hollow building panel provided by the present invention. Figure 7This is a side view of the hollow building panel provided by the present utility model. In the hollow building panel, the first bending composite section 41 in the first unit member is inserted between the first stitched flange 11 and the first panel portion 10 of the second unit member; the second bending composite section 51 in the first unit member is inserted between the second stitched flange 21 and the second panel portion 20 of the second unit member; and the first bending composite section 41 of the first unit member is kept in close contact and fixed with the first stitched flange 11 and the first panel portion 10 of the second unit member, and the second bending composite section 51 in the first unit member is kept in close contact and fixed with the second stitched flange 21 and the second panel portion 20 of the second unit member. Using these unit members to form a hollow building panel can produce corresponding technical effects. As described above, in the hollow building panel, the first connecting folded edge portion 40 and the second connecting folded edge portion 50 may further respectively include a first folding receiving concave portion 42 and a second folding receiving concave portion 52; the first folding receiving concave portion 42 connects between the first bending composite section 41 and the first panel portion 10, and the second folding receiving concave portion 52 connects between the second bending composite section 51 and the second panel portion 20; the first folding receiving concave portion 42 and the second folding receiving concave portion 52 respectively form a first folding receiving groove and a second folding receiving groove to receive the stitched folding edge. Similarly, the flatness of the surface of the hollow building panel can be improved. At the same time, the first stitched flange 11 in the first unit member can be inserted between the first bending composite section 41 and the first folding receiving concave portion 42 of the second unit member; the second stitched flange 21 in the first unit member can be inserted between the second bending composite section 51 and the second folding receiving concave portion 52 of the second unit member; and the first stitched flange 11 in the first unit member is kept in close contact and fixed with the first bending composite section 41 and the first folding receiving concave portion 42 of the second unit member; the second stitched flange 21 in the first unit member is kept in close contact and fixed with the second bending composite section 51 and the second folding receiving concave portion 52 of the second unit member. This can improve the reliability of the stitched connection and fixation between the unit members and enhance the rigidity of the hollow building panel.

[0041] Please refer to Figure 8 , Figure 8This utility model provides a cross-sectional structure diagram of a hollow building panel, showing a structural diagram of the edge sealing of the hollow building panel; in the figure, the unit components are indicated by dashed lines, and the edge unit components and the sealing components are indicated by solid lines. The hollow building panel further includes an edge unit component and a sealing component 60; the edge unit component is formed by bending a complete sheet of material, and includes a first edge panel portion 1a, a second edge panel portion 2a, and an edge core panel 3a; both ends of the edge core panel 3a are respectively connected to the inner ends of the first edge panel portion 1a and the second edge panel portion 2a through a first edge bending composite section 41a and a second edge bending composite section 51a; the first edge bending composite section 41a in the edge unit component is inserted between the first stitching flange 11 of the outermost unit component and the first panel portion 10; the second edge bending composite section 51a in the edge unit component is inserted between the second stitching flange 21 of the outermost unit component and the second panel portion 20; and the first edge bending composite section 41a of the edge unit component is kept in close contact and fixed with the first stitching flange 11 and the first panel portion 10 of the outermost unit component, and the second edge bending composite section 51a of the edge unit component is kept in close contact and fixed with the second stitching flange 21 and the second panel portion 20 of the outermost unit component;

[0042] Both sides of the sealing component 60 are respectively connected to the first edge panel portion 1a and the second edge panel portion 2a, sealing the opening on the outer side of the edge unit component. Through the edge unit component and the sealing component 60, the opening of the hollow building panel can be sealed, on the one hand, ensuring the strength and rigidity of the hollow building panel, and on the other hand, improving the safety of the hollow building panel.

[0043] In this embodiment, except for not forming the first stitching flange 11 and the second stitching flange 21, the structure and shape of the edge unit component can be the same as those of other unit components to facilitate the sealing of the opening edge of the hollow building panel. Structures such as a folding accommodation concave portion can also be formed, which will not be described in detail here.

[0044] In the embodiment, the first edge panel portion 1a and the second edge panel portion 2a can be extended in parallel, and the outer ends of the first edge panel portion 1a and the second edge panel portion 2a can be kept flush with the outer surface of the sealing component 60 to ensure the flatness of the overall contour of the hollow building panel. Right-angle flanges 61 can be respectively formed on both sides of the sealing component 60, and the two right-angle flanges 61 are respectively attached to and fixed with the inner surfaces of the first edge panel portion 1a and the second edge panel portion 2a. This can improve the strength and rigidity of the hollow building panel.

[0045] Refer again to Figure 1, in one embodiment of the present utility model, the first panel portion 10 and the second panel portion 20 are symmetrically arranged. This can ensure the flatness of the hollow building panel and avoid skew. And the cross-sectional width W1 of the first panel portion 10 is 1.3 to 1.9 times the cross-sectional width ratio W2 of the core board 30. This can ensure the supporting effect of the panel portion of the core board 30, and further ensure the strength of the hollow building panel. At the same time, the cross-sectional width W3 of the first stitching flange 11 and the second stitching flange 21 is greater than one-tenth of the cross-sectional width W1 of the first panel portion 10, which can ensure suitable connection dimensions between unit components, and further ensure the reliability of the connection between unit components in the hollow building panel.

[0046] Although the preferred embodiments of the present utility model have been described in the above description, those skilled in the relevant technical field can understand that many changes or modifications can be made in the details of design, construction or operation without departing from the scope required by the present utility model.

Claims

1. A hollow building panel, comprising a plurality of unit components arranged in sequence, characterized in that, The unit member is formed by bending a complete sheet, and includes a first panel part (10), a second panel part (20) and a core board (30); Both ends of the core board (30) are respectively connected to the inner ends of the first panel part (10) and the second panel part (20) through a first connecting folded edge part (40) and a second connecting folded edge part (50); the outer ends of the first panel part (10) and the second panel part (20) respectively form a first stitching flanging (11) and a second stitching flanging (21) that are bent inward and toward the inner end; The first bending composite section (41) in the first unit member is inserted between the first stitching flanging (11) of the second unit member and the first panel part (10); the second bending composite section (51) in the first unit member is inserted between the second stitching flanging (21) of the second unit member and the second panel part (20); and the first bending composite section (41) of the first unit member is kept in close contact and fixed with the first stitching flanging (11) and the first panel part (10) of the second unit member, and the second bending composite section (51) in the first unit member is kept in close contact and fixed with the second stitching flanging (21) and the second panel part (20) of the second unit member.

2. The hollow building panel according to claim 1, wherein In the unit member, the extending directions of the first panel part (10) and the second panel part (20) are kept parallel.

3. The hollow building panel according to claim 2, wherein, In the unit member, the extending direction of the core board (30) is perpendicular to the extending direction of the first panel part (10).

4. The hollow building panel according to claim 1, characterized in that, The first connecting folded edge part (40) and the second connecting folded edge part (50) also respectively include a first folding receiving concave part (42) and a second folding receiving concave part (52); The first folding receiving concave part (42) is connected between the first bending composite section (41) and the first panel part (10), and the second folding receiving concave part (52) is connected between the second bending composite section (51) and the second panel part (20); The first folding receiving concave part (42) and the second folding receiving concave part (52) respectively form a first folding receiving groove and a second folding receiving groove, and accommodate the stitching folding edge.

5. The hollow building panel according to claim 4, characterized in that, In the unit member, the depths of the first folding receiving groove and the second folding receiving groove are both not less than 4 times the thickness of the sheet forming the unit member.

6. The hollow building panel according to claim 5, characterized in that, The first stitching flanging (11) in the first unit member is inserted between the first bending composite section (41) of the second unit member and the first folding receiving concave part (42); the second stitching flanging (21) in the first unit member is inserted between the second bending composite section (51) of the second unit member and the second folding receiving concave part (52); and the first stitching flanging (11) in the first unit member is kept in close contact and fixed with the first bending composite section (41) and the first folding receiving concave part (42) of the second unit member; the second stitching flanging (21) in the first unit member is kept in close contact and fixed with the second bending composite section (51) and the second folding receiving concave part (52) of the second unit member.

7. The hollow building panel according to any one of claims 1 to 6, characterized in that, It also includes an edge unit member and a blocking member (60); The edge unit member is formed by bending a complete sheet, and includes a first edge panel portion (1a), a second edge panel portion (2a), and an edge core board (3a); Both ends of the edge core board (3a) are respectively connected to the inner ends of the first edge panel portion (1a) and the second edge panel portion (2a) through a first edge bending composite section (41a) and a second edge bending composite section (51a); The first edge bending composite section (41a) in the edge unit member is inserted between the first stitching flange (11) of the outermost unit member and the first panel portion (10); the second edge bending composite section (51a) in the edge unit member is inserted between the second stitching flange (21) of the outermost unit member and the second panel portion (20); and the first edge bending composite section (41a) of the edge unit member is kept in close contact and fixed with the first stitching flange (11) and the first panel portion (10) of the outermost unit member, and the second edge bending composite section (51a) of the edge unit member is kept in close contact and fixed with the second stitching flange (21) and the second panel portion (20) of the outermost unit member; Both sides of the blocking member (60) are respectively connected to the first edge panel portion (1a) and the second edge panel portion (2a) to block the opening on the outer side of the edge unit member.

8. The hollow building panel according to claim 7, characterized in that, The first edge panel portion (1a) and the second edge panel portion (2a) extend parallelly.

9. The hollow building panel according to claim 7, characterized in that, The outer ends of the first edge panel portion (1a) and the second edge panel portion (2a) are flush with the outer surface of the blocking member (60).

10. The hollow building panel according to claim 7, characterized in that, Both sides of the blocking member (60) respectively form right-angle flanges (61), and the two right-angle flanges (61) are respectively attached to and fixed with the inner surfaces of the first edge panel portion (1a) and the second edge panel portion (2a).

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