Abstract:
The present invention discloses a fastening system for a panel. The fastening system includes: at least two mounting rails which each has a plurality of engaging open cavities formed therein; and a plurality of engaging slide blocks respectively engaging with the engaging open cavities; wherein the panel is disposed on the mounting rails and fixedly connected with the engaging slide blocks respectively. Basing on the engagement structure, the present invention can be fastened on a surface of a mounted object via two rails and provide high tensile strength and simple installation. The present invention can fix different shapes of panel assemblies on a roof, the ground, a wall or a surface of a framework safely, quickly and stably, and the present invention has a simple structure, light weight and low total costs.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a National Stage of International Application No. PCT/CN2009/073302, filed Aug. 17, 2009. This application claims the benefit and priority of Chinese Application No. 200810200021.2, filed Sep. 18, 2008. The entire disclosure of each of the above applications is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a mounting and fastening system for a panel, and more particularly to a mounting system for fastening solar modules or other panels. Specifically, one or a plurality of mounting rails and one or a plurality of solar modules or other panels are fastened via fasteners and corresponding engaging slide blocks and clamps to form a fastened assembly. 
     2. Background of the Invention 
     Solar energy, as one kind of sustained clean energy, has great potential in development and application. With the present situation of increasing globe energy demand, solar photovoltaic power generation is being developed rapidly as a sustainable substitution for energy. 
     Solar photovoltaic power generation is a technology for converting solar energy into electrical energy. The core of the technology is semiconductor materials which can release electrons. The most common semiconductor material is silicon that is abundant in the earth&#39;s crust. A solar photovoltaic cell has two layers of semiconductors, of which one layer is an anode and the other layer is a cathode. The interface between the anode and the cathode produces electric current when the semiconductor is in the sun. 
     Solar photovoltaic power generation is a simple technology with low risk, which can almost be applied in any place where there is sunshine. It means that it can be disposed on roofs and walls of public and personal buildings. So solar photovoltaic power generation not only provides a lot of electric power, but also saves land occupation. 
     The most important feature of solar photovoltaic power generation is its low CO 2  emissions from power generation. As well known, CO 2 , as the main greenhouse gas, is responsible for climate change. 
     Recently, energy and environment problems become hot worldwide. For the sustainable development of energy and environment, many countries have all focused their attention on solar power. From a long-term point of view, solar photovoltaic power generation will play an important role in world energy consumption in the future. 
     A mounting system for solar photovoltaic power generation is configured by mounting one or a plurality of solar photovoltaic modules on a mounting support with a certain strength. Most of solar module manufacturers and suppliers don&#39;t produce this kind of mounting system. 
     For installation of solar modules or other panels, German Patent No. DE19717996A1 discloses a connection method of solar collectors and roof brackets. In the method, the roof anchors are fixed on the wood strips on which the tiles are placed on a roof and the other ends of the roof anchors clamp tubes on which the solar collectors are placed. The solar collectors and the tubes are fixed by another bracket. In the mounting method, the space between the tiles and the solar collectors is so small that the installation is inconvenient. 
     U.S. Pat. No. 6,105,317 only discloses a top mounting system for solar photovoltaic modules. During installation, it demands that the distance between two rails is a certain width of solar photovoltaic modules and two rails must be just located and fastened on fixed points on a surface of a mounted object. So the fixed points must be precalculated accurately and premade. 
     U.S. Pat. No. 6,360,491B1 discloses a mounting method for solar modules with slidable inserts. In the method, the bottom of the mounting rail needs to be drilled at site so that bolts can pass through the drilled holes to fasten the rail and the support. So the mounting method increases the difficulty and strength of installation, and can only be applied to the installation of the top of the solar modules. 
     German Patent No. DE10132557A1 provides a roof mounting system for solar photovoltaic modules. The mounting system fastens the solar photovoltaic modules between a press board and base rails via bolts. The tooth surfaces of the base rails and the support mounted on the roof are engaged closely via bolts so that the base rails and the support are fastened together. Since the bolts are rotated into the opening grooves formed in the base rails which are made of a relative soft material to achieve the engagement of the system, the tensile strength of the system is affected. 
     U.S. Pat. No. 7,260,918B2 provides a mounting system for solar modules or other panels. Though the system can implement the installation of tops and back surfaces of solar modules and other panels, it needs that the rigidity of rails meets the demand of the tensile strength of the system, which will increase the wall thickness of the rails and cause an increase in the amount of mounting materials. 
     US Patent Application Publication No. US200610086382A1 discloses a mounting method in which solar modules are disposed between the upper rail and the lower rail, fasteners pass through the top of the upper rail and the bottom of the lower rail to fasten the solar modules or other panels and the upper and the lower rails together and the lower rail is connected with a support rail via fasteners closely. The whole mounting system needs three rails so that the amount of mounting materials is increased greatly, thereby the mounting costs and workloads are increased. 
     US Patent Application Publication No. US2006/0156651A discloses a mounting system of an engaging slide block structure. The system needs combine mounting rails with connecting rails to form system rails, so the mounting processes are increased and the amount of mounting materials is increased. 
     Hence, in conventional mounting systems for solar modules or other panels, few products can accomplish the fastening installation of tops or bottoms of solar modules or other panels on one mounting rail and the fastening connection of solar modules or other panels and the mounting rail on a surface of a mounted object. Additionally, such conventional products, which can perform the above work using one rail, need to use heavy rails with large consumption in metals to improve tensile strength of their mounting systems, so the consumption of raw materials of the mounting systems is high. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a fastening system for a panel which can be fastened on a surface of a mounted object via two mounting rails by engaging and to provide high tensile strength and simple installation. The present invention can fix different shapes of panel assemblies on a roof, the ground, a wall or a surface of a framework safely, quickly and stably; and the present invention has a simple structure, light weight and low total costs. 
     The technical concept of the present invention is as follows: the mounting rail with engagement structures of the present mounting system includes two engaging open cavities for engaging slide blocks sliding linearly along the rail and a sliding open groove with a plane bottom for a bolt sliding linearly along the rail. A first engaging open cavity is located in the upper portion of the mounting rail and has the cross section shaped like E with a downward opening. A second engaging open cavity is located below the right side of the first engaging open cavity of the mounting rail and forms an angle of 90 degrees with the first engaging open cavity. The three base sides of the two engaging open cavities, opposite to their openings, are collinear. The sliding open groove with a plane bottom is located in the middle of the left side of the first engaging open cavity and forms an angle of 90 degrees with the first engaging open cavity. 
     In each engaging open cavity of the mounting rail, a pair of protruding portions protrudes from the inner sides of the two side lips of the opening of the cavity and engages with grooves of the engaging slide block. Each engaging open cavity further has a pair of foot poles parallel to two sides of the cavity, with a pair of feet with inclined faces formed on the top ends of the foot poles, wherein the soles of the feet with inclined faces confront and are parallel to the outside of the two side lips of the opening of the cavity, and the feet with inclined faces are parallel to each other, with the tiptoes opposite to each other and the insteps and the soles forming an acute angle therebetween. Alternatively, a pair of right-angled feet is formed on the top ends of the foot poles, wherein the soles of the right-angled feet confront and are parallel to the outside of the two side lips of the opening of the cavity, and the right-angled feet are parallel to each other, with the tiptoes opposite to each other and the insteps parallel to the soles. The two pairs of foot poles and feet separate the collinear bottoms of the two engaging open cavities, which are opposite to the openings of the two engaging open cavities, into three parts. 
     The cross section of each engaging slide block is shaped like C with a downward opening. Two grooves are formed in the cross section of the engaging slide block and respectively extend along the two ends of the engaging slide block to engage with the two protruding portions protruding from the inner sides of the two side lips of the opening of the engaging open cavity. A pair of opposite recesses with inclined faces or right-angled recesses is formed in the C-shaped opening to engage with the feet with inclined faces or right-angled feet standing oppositely in the engaging open cavity. The engagement portions of the engaging slide blocks and the engagement portions of the mounting rail are fastened via fasteners to prevent the engaging slide blocks from sliding axially along the mounting rail in the engaging open cavities and avoid that the engaging slide blocks move horizontally and vertically in the engaging open cavities of the mounting rail and the engaging open cavities of the mounting rail produce deformation when the engaging slide blocks are acted upon by an external force. A threaded hole is formed in the center position between the two grooves of the engaging slide block and may be engaged with a matching fastening bolt. 
     In the mounting system, top flanges of end clamps are pressed on the top frame strips of solar modules or other panels and bolts pass through holes of horizontal flanges of the end clamps and engage with the engaging slide blocks in the first engaging open cavity of the mounting rail, wherein the number of the engaging slides blocks corresponds to that of the end clamps, thereby the solar modules or other panels are fastened on the top end of the mounting rail. 
     In the mounting system, top flanges of middle clamps are pressed on the top frames of solar modules or other panels and bolts pass through holes of top flanges of the middle clamps and middle support, and engage with the engaging slide blocks in the first engaging open cavity of the mounting rail, wherein the number of the engaging slides blocks corresponds to that of the middle clamps, thereby the solar modules or other panels are fastened in the middle of the top of the mounting rail. 
     In the mounting system, back clamps can be fastened on solar modules or other panels via fasteners passing through holes of horizontal flanges of the back clamps and holes of back frames of solar modules or other panels. At the same time, the bolts pass through holes of vertical flanges of the back clamps and an opening slide way with a plane bottom of the mounting rail to engage with nuts, so as to fasten the back clamps on the side surface of the mounting rail. Thereby, the back surfaces of the solar modules or other panels and the back clamps are fastened on the mounting rail. 
     The mounting rail can be fastened via the engaging slide block mounted in the second engaging open cavity and a bolt passing through a vertical flange of an L-shaped fastener. The mounting rail fastened by the L-shaped fastener may be securely connected to a roof, the ground, a wall or a surface of a framework based on the engagement of a hole of a horizontal flange of the L-shaped fastener and a fastener. 
     To achieve the above-mentioned object, a fastening system for a panel in accordance with the present invention is provided. The fastening system for a panel includes: 
     at least two mounting rails, each having a plurality of engaging open cavities formed therein; and 
     a plurality of engaging slide blocks, respectively engaging with the engaging open cavities; 
     wherein the panel is disposed on the mounting rails and fixedly connected with the engaging slide blocks respectively. 
     Advantageously, the number of the engaging slide blocks is two and the number of the engaging open cavities is two, and the engaging open cavities respectively are a first engaging open cavity formed in a top surface of the mounting rail and a second engaging open cavity formed in a side surface of the mounting rail. 
     Advantageously, the panel includes a plurality of top frame strips and a back frame; and the fastening system for a panel further includes: 
     a middle clamp, including a top flange which has two side lips respectively formed on two ends thereof to engage with the top frame strips for position limitation; a pair of vertical flanges being under the top flange and a flange support disposed horizontally between the vertical flanges; wherein the middle clamp is fixedly connected with one of the engaging slide blocks, which engages with the first engaging open cavity, via a fastening bolt; and 
     an L-shaped fastener, including a vertical flange and a horizontal flange, wherein the vertical flange is fixedly connected with the other engaging slide block, which engages with the second engaging open cavity, via a fastening bolt. 
     Advantageously, a sliding open groove with a plane bottom is formed in one side of the mounting rail which is on the back side of the second engaging open cavity; and the fastening system for a panel further includes: 
     a back clamp, including a horizontal flange and a vertical flange, a side lip formed on each of the free ends of the horizontal flange and the vertical flange; and 
     a bolt, having an end shape corresponding to the shape of the sliding open groove with a plane bottom and slidably disposed in the sliding open groove with a plane bottom, wherein the vertical flange and the bolt are fastened and the horizontal flange is fixedly connected with the back frame via a bolt. 
     Advantageously, the fastening system for a panel further includes an end clamp which is Z-shaped and has a top flange, a vertical flange and a horizontal flange connected in turn, wherein the top flange has a side lip formed on the end thereof to engage with the top flange strip for position limitation; the horizontal flange is tightly connected with an engaging slide block, which is engaged with the first engaging open cavity, via a fastening bolt. 
     Advantageously, the engaging slide block has two parallel grooves formed in an upper surface thereof and two parallel recesses with inclined faces or right-angled recesses formed in a lower surface thereof; 
     each of the first engaging open cavity and the second engaging open cavity has a pair of protruding portions engaged with the grooves and a pair of parallel foot poles which has a pair of feet with inclined faces or right-angled feet formed on top ends thereof, and the pair of feet with inclined faces or right-angled feet is engaged with the recesses with inclined faces or the right-angled recesses of the engaging slide block. 
     Advantageously, the panel ( 14 ) is a solar panel module. 
     Accordingly, comparing with the prior art, the present invention has the advantages as follows: basing on the engagement structure of the present invention, different sizes and shapes of solar modules or other panels can be fixed on a roof, the ground, a wall or a surface of a framework more safely, quickly and stably; and the present invention has the advantages of high tensile strength, light weight, simple installation and low costs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a fastening system of the present invention; 
         FIG. 2  is an enlarged view of engagement portions of mounted assemblies in  FIG. 1 ; 
         FIG. 3  is a perspective view f a mounting rail of the present invention; 
         FIG. 4  is a front view of a mounting rail of the present invention; 
         FIG. 4A  is a front view of a mounting rail of a preferred embodiment of the present invention; 
         FIG. 4B  is a front view of a mounting rail of another preferred embodiment of the present invention; 
         FIG. 5A  is a perspective view of an engaging slide block of a preferred embodiment of the present invention; 
         FIG. 5B  is a perspective view of an engaging slide block of another preferred embodiment of the present invention; 
         FIG. 7  is a front view of a middle clamp of the present invention, fixed on the top of the mounting rail; 
         FIG. 8  is a front view of a back clamp of the present invention, mounted on one side of the mounting rail and fixed on a surface of an object; 
         FIG. 9  is a front view of a panel and an end clamp of the present invention, fixed on the top of the mounting rail; 
         FIG. 10  is a perspective view of the middle clamp of the present invention; 
         FIG. 11  is a perspective view of the back clamp of the present invention; 
         FIG. 12  is a perspective view of the end clamp of the present invention; 
         FIG. 13  is a perspective view of the L-shaped fastener of the present invention; and 
         FIG. 14  is a cross-sectional view of the panel of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 1 , number  5  indicates engaging slide blocks, number  10  indicates middle clamps, number  13  indicates L-shaped fasteners, and numbers  151  and  153  indicates fastening bolts. The preferred embodiment includes a panel  14  and two mounting rails  1 , and the panel  14  is disposed on the mounting rails  1  to form a mounting system for solar modules or a plurality of other panels. The mounting rails  1  are formed by extruding aluminum alloy. 
     As shown in  FIGS. 2-4 , the mounting rails  1  each has a first engaging open cavity  21 , a second engaging open cavity  23 , a sliding open groove with a plane bottom  26 , and two cavities  29 ,  30  which are spaced by a support  17 . 
     The first engaging open cavity  21  is located in the upper portion of the section of the mounting rail  1  and extends axially along the mounting rail  1 . The second engaging open cavity  23  is located below the right side of the first engaging open cavity  21  and forms an angle of 90 degrees with the first engaging open cavity  21 , and the second engaging open cavity  23  extends axially along the mounting rail  1 . The sliding open groove with a plane bottom  26  is located in the middle of the left side of the first engaging open cavity  21  and forms an angle of 90 degrees with the first engaging open cavity  21 , and the sliding open groove with a plane bottom  26  extends axially along the mounting rail  1 . The two cavities  29 ,  30  are located on the left of the second engaging open cavity  23  and extend axially along the mounting rail  1 . 
     As shown in  FIG. 2  and  FIG. 7 , a middle clamp  10  (in  FIG. 10 ) and an engaging slide block  5  (in  FIG. 5 ) are disclosed. The engaging slide block  5  has the shape corresponding to that of the first engaging open cavity  21  and extends into the first engaging open cavity  21 . The middle clamp  10  and the engaging slide block  5  are fixedly connected via a fastening bolt  151 . 
     As shown in  FIG. 7  and  FIG. 10 , the middle clamp  10  includes a top flange  109  which has two side lips  102  respectively formed on two ends thereof and a hole  104  defined in the middle thereof. A pair of vertical flanges  101  is located under the top flange  109 . A flange support  108  is disposed horizontally between the vertical flanges  101 . A hole  105  is formed in the middle of the flange support  108 , and the centers of the holes  104 , 105  are on the same axis. The fastening bolt  151  passes through the hole  104  and the hole  105 . The vertical flanges  101  are attached to the edges of the rim of the panel  14  closely and two top frame strips  144  of the panel  14  are limited between the side lips  102  and the vertical flanges  101  by the side lips  102 . 
     As shown in  FIG. 5A , two grooves  51  are formed in the section of the engaging slide block  5 , respectively extending along the two ends of the engaging slide block  5 . A threaded hole  55  is formed in the center position between the two grooves  51  and may be engaged with a matching fastening bolt  151 . A downward opening is formed in the section of the engaging slide block  5  and a pair of opposite recesses with inclined faces  52  is formed in the depressed portion of the downward opening. Alternatively, in another preferred embodiment of the present invention, a pair of opposite right-angled recesses  52 ′ is formed in the depressed portion of the downward opening, as show in  FIG. 5B . 
     As shown in  FIG. 4A , the first engaging open cavity  21  has a pair of protruding portions  211  protruding from the inner sides of the two side lips of the opening of the cavity  21 , which may engage with the grooves  51  of the engaging slide block  5  (see  FIG. 5 ). The first engaging open cavity  21  further has a pair of parallel foot poles  213  parallel to side wings formed on two sides of the opening of the cavity  21 , which separates the bottom of the cavity  21  into three parts. A pair of feet with inclined faces  212  is formed on the top ends of the foot poles  213  to engage with the recesses with inclined faces  52  (see  FIG. 5A ). Alternatively, in another preferred embodiment of the present invention, a pair of right-angled feet  212 ′ is disposed on the top ends of foot poles  213 ′ to engage with the right-angled recesses  52 ′ (see  FIG. 5B ). The pair of right-angled feet  212 ′ may act as hooks to engage with the right-angled recesses  52 ′ firmly. In this way, the engaging slide block  5  is assembled in the first engaging open cavity  21  (in  FIG. 2 ). 
     During the assembly of the middle clamp  10 , the fastening bolt  151  passes through the hole  104  and the hole  105  of each of one or a plurality of middle clamps  10  in turn and engages with the threaded hole  55  of each of one or a plurality of the engaging slide blocks  5  disposed in the first engaging open cavity  21  (see  FIG. 2 ,  FIG. 3 ,  FIG. 5  and  FIG. 10 ). 
     As shown in  FIG. 2 ,  FIG. 6  and  FIG. 8 , the L-shaped fastener  13  (in  FIG. 13 ) and the engaging slide block  5  ( FIG. 5 ) are assembled. The engaging slide block  5  has the shape corresponding to that of the second engaging open cavity  23  and extends to the second engaging open cavity  23 . One end of the L-shaped fastener  13  is fixedly connected with the engaging slide block  5  via the fastening bolt  153  and the other end thereof may be securely connected to a roof, the ground, a wall or a surface of a framework. 
     As shown in  FIG. 13 , the vertical flange  134  of the L-shaped fastener  13  has two holes  132 ,  133  formed therein and the horizontal flange  135  thereof has a hole  131  formed therein. 
     As shown in  FIG. 4A , the second engaging open cavity  23  has a pair of protruding portions  231  protruding from the inner sides of the two side lips of the opening of the cavity  23 , which may engage with the grooves  51  of the engaging slide block  5  (see  FIG. 5 ). The second engaging open cavity  23  further has a pair of parallel foot poles  233  parallel to side wings formed on two sides of the opening of the cavity  23 , which separates the bottom of the cavity  23  into three parts. A pair of feet with inclined faces  232  is formed on the top ends of the foot poles  233  to engage with the recesses with inclined faces  52  (see  FIG. 5 ). Alternatively, in another preferred embodiment of the present invention, a pair of right-angled feet  232 ′ is disposed on the top ends of foot poles  233 ′ to engage with right-angled recesses  52 ′ (see  FIG. 5B ). The pair of right-angled feet  232 ′ may act as hooks to engage with the right-angled recesses  52 ′ firmly. 
     During assembly, as shown in  FIG. 6  and  FIG. 8 , the fastening bolt  153  passes through the hole  132  or the hole  133  of the vertical flange  134  of each of one or a plurality of the L-shaped fasteners  13  (see  FIG. 13 ) and engages with the threaded hole  55  of each of one or a plurality of the engaging slide blocks  5  which is mounted in the second engaging open cavity  23  formed in the lower right side of the mounting rail  1  (see  FIG. 4  and  FIG. 5 ). The horizontal flange  135  of the L-shaped fastener  13  may be securely connected to a roof, the ground, a wall or a surface of a framework. Thereby, the panel  14 , the mounting rail  1 , the middle clamp  10 , the engaging slide block  5  and the L-shaped fastener  13  establish a secure connection for the top installation of the mounting rail. 
     As shown in  FIG. 4  and  FIG. 8 , a back clamp  11  (in  FIG. 11 ) and a bolt  155  are disclosed. The bolt  155  has the shape corresponding to that of the sliding open groove with a plane bottom  26  and extends into the sliding open groove with a plane bottom  26 . The back clamp  11  and the sliding open groove with a plane bottom  26  are connected via the bolt  155 . 
     As shown in  FIG. 11 , the back clamp  11  is a connecting member for connecting the mounting rail  1  with the panel  14  on the back side (see  FIG. 1 ). A horizontal flange  114  and a vertical flange  115  of the back clamp  11  form a right angle therebetween. A side lip  111  is formed on each of the free ends of the horizontal flange  114  and the vertical flange  115 . The horizontal flange  114  has a hole  112  formed in the center thereof and the vertical flange  115  has a hole  113  formed in the center thereof. 
     As shown in  FIG. 4 , the sliding open groove with a plane bottom  26  has two side lips  15  respectively formed on the two sides thereof, which engage with the end of the bolt  155  (see  FIG. 8 ). 
     In assembly, as shown in  FIG. 8 ,  FIG. 4  and  FIG. 11 , the fastening bolt  155 , which is disposed in the sliding open groove with a plane bottom  26 , passes through the hole  133  of the vertical flange  115  of the back clamp  11  and engages with a matching nut  156  to fasten the mounting rail  1  and the back clamp  11 , so that the back clamp  11  is fixed on the side of the mounting rail  1  tightly. A bolt  157  passes through the hole  112  of the horizontal flange  114  of the back clamp  11  and a hole  145  (in  FIG. 14 ) of a back frame  146  of the panel  14  and engages with a matching nut  158 . Accordingly, the back side of the panel  14  is fixed on the horizontal flange  114  of the back clamp  11 . 
     As shown in  FIG. 9 , a Z-shaped end clamp  12  (in  FIG. 12 ) is tightly connected with the engaging slide block  5  via a fastening bolt  159  (not shown), wherein the engaging slide block  5  is disposed in the first engaging open cavity  21  of the mounting rail  1 . 
     As shown in  FIG. 12 , the end clamp  12  has a side lip  122  formed on the end of the top flange  124  thereof. One end of the vertical flange  125  forms an angle of 90 degrees with the top flange  124  and the other end thereof forms an angle of 90 degrees with the horizontal flange  126  which has a hole  121  formed in the center thereof. 
     During assembly, as shown in  FIG. 9 , the top frame strip  144  of the panel  14  contacts with the top flange  124  of the end clamp  12  closely, and the edge of one end of the panel  14  contacts with the vertical flange  125  of the end clamp  12  closely. The side lip  122  can prevent the panel  14  from moving away from the vertical flange  125  along the axis of the mounting rail  1  after the fastening bolt  159  passes through the hole  121  (not shown) to fasten the side lip  122  and the engaging slide block  5 . 
     It will be understood by those skilled in the art that what are disclosed above are only the specification and the drawings of the preferred embodiment of the present invention and it is therefore not intended that the present invention be limited to the particular embodiment disclosed. It will be understood that various equivalent changes may be made depending on the specification and the drawings of the present invention without departing from the scope of the present invention. 
     LIST OF REFERENCE NUMERALS 
       1  mounting rail,  5  engaging slide block,  51  groove,  52  recess with an inclined face,  52 ′ right-angled recess,  55  threaded hole,  10  middle clamp,  101  vertical flange,  102  side lip,  104 ,  105  hole,  108  flange support,  109  top flange,  11  back clamp,  111  side lip,  112 ,  113  hole,  114  horizontal flange,  115  vertical flange,  12  end clamp,  121  hole,  122  side lip,  124  top flange,  125  vertical flange,  126  horizontal flange,  13  L-shaped fastener,  131 ,  132 ,  133  hole,  134  vertical flange,  135  horizontal flange,  14  panel,  144  top frame strip,  145  hole,  146  back frame,  151 ,  153 ,  155 ,  157 ,  159  fastening bolt,  156 ,  158  nut,  17  support,  21  first engaging open cavity,  211  protruding portion,  212  foot with an inclined face,  212 ′ right-angled foot,  213 ,  213 ′ foot pole,  23  second engaging open cavity,  231  protruding portion,  232  foot with a inclined face,  232 ′ right-angled foot,  233 ,  233 ′ foot pole,  26  sliding open groove with a plane bottom,  29 ,  30  cavity