CN220964695U

CN220964695U - Photovoltaic installation support

Info

Publication number: CN220964695U
Application number: CN202322855478.XU
Authority: CN
Inventors: 罗菁; 程熳
Original assignee: Shenzhen Antaike Clean Energy Co ltd
Current assignee: Shenzhen Antaike Clean Energy Co ltd
Priority date: 2023-10-24
Filing date: 2023-10-24
Publication date: 2024-05-14
Anticipated expiration: 2033-10-24

Abstract

The utility model belongs to the technical field of photovoltaics, and particularly relates to a photovoltaic mounting bracket, which comprises at least two rows of photovoltaic brackets arranged at intervals along a first direction, wherein each row of photovoltaic brackets comprises two side stand frames arranged along a second direction and a middle stand frame positioned between the two side stand frames; an upper bearing rope and a lower bearing rope positioned below the upper bearing rope are connected between the middle vertical frame and any side vertical frame in the same row of photovoltaic brackets, and the upper bearing rope is used for installing a photovoltaic module; a first stable rope and a second stable rope are connected between the adjacent photovoltaic brackets, the first stable rope and the second stable rope are connected between the upper bearing rope and the lower bearing rope, the first stable rope and the second stable rope extend along the second direction, and the first stable rope and the second stable rope are arranged at intervals in the third direction. The photovoltaic mounting bracket provided by the utility model can enhance the stability of connection between the two side stand columns and the middle stand column and weaken vibration in the height direction.

Description

Photovoltaic installation support

Technical Field

The utility model belongs to the technical field of photovoltaics, and particularly relates to a photovoltaic mounting bracket.

Background

The existing photovoltaic mounting bracket structure system in the photovoltaic array generally adopts double-cable support (without additional cables and space trusses) and three-cable support, and the structure dead weight and acting force under the wind and snow working condition are resisted by applying prestress to the double cables which are in direct contact with the photovoltaic module. However, because the photovoltaic installation support is supported by adopting a flexible cable structure, if the photovoltaic installation support has a large span, the photovoltaic installation support is extremely easy to generate large vibration due to factors such as small structural rigidity, large mid-span deflection, weak wind resistance and the like.

Disclosure of utility model

The utility model aims to provide a photovoltaic mounting bracket, which aims to solve the technical problems that the existing photovoltaic mounting bracket adopts a flexible cable structure for supporting, and if the photovoltaic mounting bracket is large in span, the photovoltaic mounting bracket is extremely easy to generate large vibration due to factors such as small structural rigidity, large mid-span deflection, weak wind resistance and the like.

In order to achieve the above purpose, the utility model adopts the following technical scheme: the photovoltaic installation support comprises at least two rows of photovoltaic supports which are arranged at intervals along a first direction, wherein each row of photovoltaic supports comprises two side stand frames arranged along a second direction and a neutral frame arranged between the two side stand frames; an upper bearing cable and a lower bearing cable positioned below the upper bearing cable are connected between the middle vertical frame and any side vertical frame in the same row of photovoltaic brackets, and the upper bearing cable is used for installing a photovoltaic module;

A first stabilizing rope and a second stabilizing rope are connected between the adjacent photovoltaic brackets, the first stabilizing rope and the second stabilizing rope are connected between the upper bearing rope and the lower bearing rope, the first stabilizing rope and the second stabilizing rope extend along the second direction, the first stabilizing rope and the second stabilizing rope are arranged at intervals in the third direction, and the first direction, the second direction and the third direction are mutually perpendicular.

In some embodiments, the photovoltaic mounting bracket further comprises at least two stabilizing posts extending along the third direction, the at least two stabilizing posts being spaced apart in the second direction, the at least two stabilizing posts collectively supporting and mounting the first and second stabilizing cables.

In some embodiments, the side stand comprises a side stand and a side cross member mounted on the side stand;

The middle frame comprises a middle upright post and a middle cross beam arranged on the middle upright post;

the upper bearing cable and the lower bearing cable are connected between the side cross beam and the middle cross beam.

In some embodiments, the upper load-bearing cable includes a first portion and a second portion within the photovoltaic bracket in the same row, the first portion and the second portion forming a height structure in the third direction.

In some embodiments, in the same side stand, the side stand comprises a first stand and a second stand, the heights of the first stand and the second stand in the third direction are consistent, and two ends of the side cross beam are respectively arranged on the first stand and the second stand;

The side stand still includes along the first reinforcement truss that the third direction extends, first reinforcement truss locate the limit crossbeam just with first stand corresponds, first part is located first reinforcement truss deviates from one side of limit crossbeam, the second part is located the limit crossbeam deviates from one side of first reinforcement truss.

In some embodiments, the middle cross beam is perpendicular to the middle column, the middle frame further comprises a second reinforcing truss extending along the third direction, the second reinforcing truss is arranged on the middle cross beam, the first part is arranged on one side, away from the middle cross beam, of the second reinforcing truss, and the second part is arranged on the middle cross beam.

In some embodiments, the neutral frame further comprises a first diagonal brace connected between one end of the center cross member and the center post and a second diagonal brace connected between the other end of the center cross member and the center post.

In some embodiments, the neutral frame further comprises a first connector and a second connector, the first connector and the second connector being cross-connected between two adjacent neutral posts.

In some embodiments, the first stabilizing wire is connected between the first portion and the second portion of the adjacent photovoltaic brackets, and the second stabilizing wire is connected between lower load-bearing wires of the adjacent photovoltaic brackets;

The photovoltaic mounting bracket further comprises a support frame connected between the first stabilizing rope and the second stabilizing rope, and the support frame can be used for mounting a photovoltaic module.

In some embodiments, the support frame comprises a first support rod, a second support rod and a third support rod, wherein the first support rod and the second support rod are respectively connected between the first stable rope and the second stable rope, and one end of the first support rod extends out of the first stable rope; the third support rod is connected between the first support rod and the second support rod, is positioned at one side of the first stabilizing rope, which is away from the second stabilizing rope, and can be used for installing a photovoltaic assembly;

the first support rods, the second support rods and the third support rods are arranged in a triangular mode.

In some embodiments, the support frame further comprises a fourth support bar, one end of the fourth support bar is connected to the connection part of the first support bar and the second support bar, and the other end of the fourth support bar is connected between two ends of the third support bar.

According to the photovoltaic mounting bracket provided by the utility model, the middle vertical frame is arranged between the two side vertical frames of each row of photovoltaic brackets, so that the photovoltaic with larger span is partitioned, and the occurrence of large-scale vibration can be avoided. Meanwhile, a first stable rope and a second stable rope are connected between adjacent photovoltaics, the first stable rope and the second stable rope are connected between the upper bearing rope and the lower bearing rope, the first stable rope and the second stable rope extend along the second direction, the first stable rope and the second stable rope are arranged at intervals in the third direction, the stability of connection between the two side stand columns and the middle stand column can be enhanced, and vibration in the height direction is weakened.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a photovoltaic bracket of the photovoltaic mounting bracket according to an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of a photovoltaic mounting bracket at an edge riser according to an embodiment of the present utility model;

FIG. 3 is a schematic cross-sectional view of a photovoltaic mounting bracket at a neutral frame provided by an embodiment of the present utility model;

FIG. 4 is a schematic cross-sectional view of a photovoltaic mounting bracket at a neutral frame according to another embodiment of the present utility model;

fig. 5 is a schematic cross-sectional view of a photovoltaic mounting bracket provided by an embodiment of the present utility model between an edge stand and a neutral stand.

Wherein, each reference sign in the figure:

1-side stand; 11-side columns; 111-a first upright; 112-a second upright; 113-a first stiffening truss; 12-side cross beams; 2-a neutral frame; 21-a central column; 22-middle cross beam; 23-a second reinforcing truss; 24-a first diagonal brace; 25-second diagonal braces; 26-a first connector; 27-a second connector; 3-upper bearing rope; 31-a first part; 32-a second portion; 4-lower bearing ropes; 51-a first stabilizing cable; 52-a second stabilizing cable; 6-stabilizing the upright post; 7-supporting frames; 71-a first support bar; 72-a second support bar; 73-a third support bar; 74-a fourth support bar; y-a second direction; z-a third direction; 8-photovoltaic module.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Referring to fig. 1 to 5, a description will now be given of a photovoltaic mounting bracket provided by the present utility model, which includes at least two rows of photovoltaic brackets disposed at intervals along a first direction, each row of photovoltaic brackets including two side uprights 1 disposed along a second direction Y and a neutral frame 2 located between the two side uprights 1.

In the same row of photovoltaic brackets, all be connected with the upper bearing cable 3 between well creel 2 and arbitrary side gruel 1 and be located the lower bearing cable 4 of upper bearing cable 3 below, upper bearing cable 3 is used for installing photovoltaic module 8.

A first stabilizing rope 51 and a second stabilizing rope 52 are connected between the adjacent photovoltaic brackets, the first stabilizing rope 51 and the second stabilizing rope 52 are connected between the upper bearing rope 3 and the lower bearing rope 4, the first stabilizing rope 51 and the second stabilizing rope 52 extend along the second direction Y, the first stabilizing rope 51 and the second stabilizing rope 52 are arranged at intervals in the third direction Z, and the first direction, the second direction Y and the third direction Z are mutually perpendicular.

Here, the third direction Z is generally a vertical direction.

In practical application, the number of the first stabilizer wires 51 and the second stabilizer wires 52 may be multiple, the first stabilizer wires 51 are arranged at intervals in the second direction Y, the second stabilizer wires 52 are arranged at intervals in the second direction Y, and the first stabilizer wires 51 and the second stabilizer wires 52 are arranged in one-to-one correspondence.

According to the photovoltaic installation support, the middle vertical frame 2 is arranged between the two side vertical frames 1 of each row of photovoltaic support, and the photovoltaic with larger span is partitioned, so that the occurrence of large-amplitude vibration can be avoided. Meanwhile, the first stabilizing rope 51 and the second stabilizing rope 52 are connected between the adjacent photovoltaics, the first stabilizing rope 51 and the second stabilizing rope 52 are connected between the upper bearing rope 3 and the lower bearing rope 4, the first stabilizing rope 51 and the second stabilizing rope 52 extend along the second direction Y, the first stabilizing rope 51 and the second stabilizing rope 52 are arranged at intervals in the third direction Z, the stability of connection between the two side uprights 11 and the middle upright 21 can be enhanced, and vibration in the height direction is weakened.

In some embodiments, as shown in fig. 5, the photovoltaic mounting bracket further comprises at least two stabilizing posts 6 extending along the third direction Z, the at least two stabilizing posts 6 being spaced apart in the second direction Y, the at least two stabilizing posts 6 together supporting and mounting the first stabilizing cable 51 and the second stabilizing cable 52.

When the number of the stabilizing upright posts 6 is two, the two stabilizing upright posts 6 are respectively positioned on the first row of photovoltaic brackets and the tail row of photovoltaic brackets, and both ends of the first stabilizing cable 51 and both ends of the second stabilizing cable 52 are respectively connected with the first row of photovoltaic brackets and the tail row of photovoltaic brackets.

When the number of the stabilizing upright posts 6 is three, two of the stabilizing upright posts 6 are respectively positioned on the first row of photovoltaic brackets and the tail row of photovoltaic brackets, the other stabilizing upright post 6 is positioned on the middle photovoltaic bracket between the first row of photovoltaic brackets and the tail row of photovoltaic brackets, two ends of the first stabilizing cable 51 and two ends of the second stabilizing cable 52 are respectively connected with the first row of photovoltaic brackets and the tail row of photovoltaic brackets, and the middle photovoltaic brackets can be used for supporting the two ends of the first stabilizing cable 51 and the two ends of the second stabilizing cable 52, so that the span of the first stabilizing cable 51 and the second stabilizing cable 52 in the second direction Y is overlarge, and the occurrence of large vibration can be avoided.

It will be understood that the number of the stabilizing posts 6 may be further, and the greater the number of the stabilizing posts 6, the better the stability of the photovoltaic mounting bracket, but the more material required for the photovoltaic mounting bracket, and those skilled in the art may actually need to select the setting.

In one embodiment, as shown in fig. 2, the side stand 1 includes a side stand 11 and a side cross member 12 mounted on the side stand 11. The neutral frame 2 includes a center pillar 21 and a center cross member 22 mounted on the center pillar 21. The upper and lower load-bearing cables 3, 4 are connected between the side rails 12 and the center rail 22. In this way, the stability of the photovoltaic mounting bracket can be enhanced.

In one embodiment, as shown in fig. 2 and 3, in the photovoltaic brackets in the same row, the upper load-bearing cable 3 includes a first portion 31 and a second portion 32, and the first portion 31 and the second portion 32 form a height structure in the third direction Z. In this way, an angle is formed between the connecting line between the first portion 31 and the second portion 32 and the horizontal plane, so that the photovoltaic modules 8 mounted on the first portion 31 and the second portion 32 are obliquely arranged. The angle between the line between the first portion 31 and the second portion 32 and the horizontal may be chosen according to the angle at which the photovoltaic module 8 is tilted, for example, in some embodiments, the angle at which the photovoltaic module 8 is tilted is 15 °, and the angle between the line between the first portion 31 and the second portion 32 and the horizontal is also 15 °.

In an embodiment, as shown in fig. 2, in the same side stand 1, the side stand 11 includes a first stand 111 and a second stand 112, the heights of the first stand 111 and the second stand 112 in the third direction Z are identical, two ends of the side beam 12 are respectively disposed on the first stand 111 and the second stand 112, and at this time, the side beam 12 is disposed horizontally; the side stand 1 further comprises a first reinforcing truss 113 extending in the third direction Z, the first reinforcing truss 113 is arranged on the side beam 12 and corresponds to the first upright 111, the first portion 31 is arranged on one side of the first reinforcing truss 113 away from the side beam 12, and the second portion 32 is arranged on one side of the side beam 12 away from the first reinforcing truss 113.

Specifically, since the side cross beam 12 is horizontally disposed, the first reinforcing truss 113 extends along the third direction Z and is disposed on the side cross beam 12, and therefore, the height of the side of the first reinforcing truss 113 facing away from the side cross beam 12 in the third direction Z is greater than the height of the side cross beam 12; because the first portion 31 of the upper load-bearing cable 3 is disposed on the side of the first reinforcing truss 113 away from the side beam 12, and the second portion 32 of the upper load-bearing cable 3 is disposed on the side of the side beam 12 away from the first reinforcing truss 113, the first portion 31 and the second portion 32 can form a high-low structure in the third direction Z, so that the photovoltaic module 8 can be obliquely mounted. Meanwhile, the first reinforcement truss 113 is arranged to form a high-low structure on the first part 31 and the second part 32 of the upper bearing cable 3 in the third direction Z, so that compared with the scheme that two ends of the side cross beam 12 are arranged to be different in height, which is commonly adopted in the prior art, the material of the photovoltaic installation bracket can be saved, and the cost can be reduced.

In one embodiment, as shown in fig. 3, the middle cross member 22 is perpendicular to the middle column 21, the middle frame 2 further includes a second reinforcing truss 23 extending along the third direction Z, the second reinforcing truss 23 is disposed on the middle cross member 22, the first portion 31 is disposed on a side of the second reinforcing truss 23 facing away from the middle cross member 22, and the second portion 32 is disposed on the middle cross member 22.

Specifically, since the middle cross member 22 is horizontally disposed, the second reinforcing truss 23 extends along the third direction Z and is disposed on the middle cross member 22, and therefore, the height of the side of the second reinforcing truss 23 facing away from the middle cross member 22 in the third direction Z is greater than the height of the middle cross member 22; since the first portion 31 of the upper load-bearing cable 3 is disposed on the side of the second reinforcing truss 23 facing away from the middle cross member 22, and the second portion 32 of the upper load-bearing cable 3 is disposed on the middle cross member 22, the first portion 31 and the second portion 32 can form a high-low structure in the third direction Z, so that the photovoltaic module 8 can be mounted obliquely. Meanwhile, the first part 31 and the second part 32 of the upper load-bearing cable 3 are formed into a high-low structure in the third direction Z by arranging the second reinforcing truss 23, and compared with the scheme that two ends of the middle cross beam 22 are arranged to be different in height in the prior art, the photovoltaic installation support can save materials, and therefore cost can be reduced.

In other embodiments, the middle beam 22 and the middle column 21 may not be perpendicular, and the middle beam 22 and the horizontal plane may be disposed obliquely, i.e., the two ends of the middle beam 22 are disposed at different heights, so that the photovoltaic module 8 can be mounted obliquely, and at this time, in order to enhance the stability of the middle column 21, the two ends of the middle beam 22 are connected to the middle column 21 through connection structures respectively.

In one embodiment, as shown in fig. 3, the neutral frame 2 further includes a first diagonal brace 24 and a second diagonal brace 25, the first diagonal brace 24 is connected between one end of the center cross member 22 and the center pillar 21, and the second diagonal brace 25 is connected between the other end of the center cross member 22 and the center pillar 21. In this way, the stability of the center pillar 21 can be enhanced.

In one embodiment, as shown in fig. 4, the neutral frame 2 further includes a first connector 26 and a second connector 27, where the first connector 26 and the second connector 27 are cross-connected between two adjacent neutral posts 21. In this way, the stability of the center pillar 21 can be enhanced.

In practical applications, the first connecting piece 26 and the second connecting piece 27 may be cross-connected between all adjacent two center posts 21. All the neutral brackets 2 may include a first diagonal brace 24 and a second diagonal brace 25, the first diagonal brace 24 being connected between one end of the center cross member 22 and the center pillar 21, and the second diagonal brace 25 being connected between the other end of the center cross member 22 and the center pillar 21. As shown in fig. 4, a first connector 26 and a second connector 27 may be cross-connected between two adjacent middle columns 21, the rest middle columns 2 each include a first diagonal brace 24 and a second diagonal brace 25, at this time, the first connector 26 and the second connector 27 may be connected between a plurality of adjacent middle columns 21 located in the front row and a plurality of adjacent middle columns 21 located in the rear row, and the rest middle columns 2 each include a first diagonal brace 24 and a second diagonal brace 25.

In one embodiment, as shown in fig. 5, a first stabilizing cable 51 is connected between the first portion 31 and the second portion 32 of an adjacent photovoltaic bracket, and a second stabilizing cable 52 is connected between the lower load-bearing cables 4 of an adjacent photovoltaic bracket; the photovoltaic mounting bracket further comprises a support bracket 7 connected between the first and second stabilizing cables 51, 52, the support bracket 7 being operable to mount a photovoltaic module 8.

The number of the supporting frames 7 can be the same as that of the photovoltaic brackets, and can be different from that of the photovoltaic brackets, and the supporting frames can be selected and arranged according to actual needs.

In one embodiment, as shown in fig. 5, the supporting frame 7 includes a first supporting rod 71, a second supporting rod 72 and a third supporting rod 73, the first supporting rod 71 and the second supporting rod 72 are respectively connected between the first stabilizing cable 51 and the second stabilizing cable 52, and one end of the first supporting rod 71 extends out of the first stabilizing cable 51; the third supporting rod 73 is connected between the first supporting rod 71 and the second supporting rod 72 and is positioned on one side of the first stabilizing cable 51, which is away from the second stabilizing cable 52, and the third supporting rod 73 can be used for installing the photovoltaic module 8; the first support rod 71, the second support rod 72 and the third support rod 73 are arranged in a triangle, and the stability of the photovoltaic mounting bracket can be further enhanced due to the stability of the triangle.

Specifically, since one end of the first support rod 71 extends out of the first stabilizing cable 51, and the third support rod 73 is connected between the first support rod 71 and the second support rod 72, the third support rod is disposed obliquely to the horizontal plane, so that the photovoltaic module 8 can be installed obliquely.

Preferably, the first stabilizer cable 51, the second stabilizer cable 52 and the supporting frame 7 are all made of C-shaped steel, that is, the first supporting rod 71, the second supporting rod 72 and the third supporting rod 73 are all made of C-shaped steel.

In one embodiment, as shown in fig. 5, the support frame 7 further includes a fourth support rod 74, one end of the fourth support rod 74 is connected to the connection between the first support rod 71 and the second support rod 72, and the other end of the fourth support rod 74 is connected between two ends of the third support rod 73. Thus, not only the structure of the support frame 7 can be stabilized by the fourth support bar 74, but also additional support can be provided for the third support bar 73 by the fourth support bar 74, so that the installation of the photovoltaic module 8 is stabilized.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.

Claims

1. The photovoltaic installation support is characterized by comprising at least two rows of photovoltaic supports which are arranged at intervals along a first direction, wherein each row of photovoltaic supports comprises two side stand frames arranged along a second direction and a middle stand frame arranged between the two side stand frames; an upper bearing cable and a lower bearing cable positioned below the upper bearing cable are connected between the middle vertical frame and any side vertical frame in the same row of photovoltaic brackets, and the upper bearing cable is used for installing a photovoltaic module;

2. The photovoltaic mounting bracket of claim 1 further comprising at least two stabilizing posts extending along the third direction, the at least two stabilizing posts being spaced apart in the second direction, the at least two stabilizing posts collectively supporting and mounting the first and second stabilizing cables.

3. The photovoltaic mounting bracket of claim 1 wherein the side stand comprises a side post and a side beam mounted on the side post;

4. The photovoltaic mounting bracket of claim 3 wherein the upper load carrying cable comprises a first portion and a second portion within the same row of photovoltaic brackets, the first portion and the second portion forming a height structure in the third direction.

5. The photovoltaic mounting bracket of claim 4, wherein the side uprights include a first upright and a second upright in the same side upright, the first upright and the second upright have the same height in the third direction, and two ends of the side cross beam are respectively arranged on the first upright and the second upright;

6. The photovoltaic mounting bracket of claim 4 wherein the central beam is perpendicular to the central column, the central frame further comprising a second stiffening truss extending in the third direction, the second stiffening truss being disposed on the central beam, the first portion being disposed on a side of the second stiffening truss facing away from the central beam, the second portion being disposed on the central beam.

7. The photovoltaic mounting bracket of claim 4 wherein the neutral frame further comprises a first diagonal brace connected between one end of the center cross member and the neutral post and a second diagonal brace connected between the other end of the center cross member and the neutral post.

8. The photovoltaic mounting bracket of claim 4 wherein the neutral frame further comprises a first connector and a second connector, the first connector and the second connector being cross-connected between adjacent ones of the neutral posts.

9. The photovoltaic mounting bracket of claim 4 wherein the first stabilizing strand is connected between the first portion and the second portion of an adjacent photovoltaic bracket and the second stabilizing strand is connected between lower load-bearing strands of an adjacent photovoltaic bracket;

10. The photovoltaic mounting bracket of claim 9, wherein the support frame comprises a first support bar, a second support bar, and a third support bar, the first support bar and the second support bar are respectively connected between the first stabilizing cable and the second stabilizing cable, and one end of the first support bar extends out of the first stabilizing cable; the third support rod is connected between the first support rod and the second support rod, is positioned at one side of the first stabilizing rope, which is away from the second stabilizing rope, and can be used for installing a photovoltaic assembly;

11. The photovoltaic mounting bracket of claim 10 wherein the support frame further comprises a fourth support bar, one end of the fourth support bar being connected to the junction of the first support bar and the second support bar, the other end of the fourth support bar being connected between the ends of the third support bar.