Patent Publication Number: US-2022231398-A1

Title: Housing unit

Description:
TECHNICAL FIELD 
     The present invention relates to a housing unit including containers for housing a cable. 
     BACKGROUND ART 
     A technique to bury a wireless communication device for use as a wireless base station or the like in the ground has been known. Techniques of this type are disclosed in, for example, Patent Documents 1 and 2. 
     Patent Document 1 discloses a ground burial type antenna device adapted to be disposed below a lid and equipped with an installation base having a height adjustment mechanism for adjusting the distance from an antenna element to the lid. 
     Patent Document 2 discloses an antenna device adapted to be installed in an underground space such as a manhole or handhole, and a communication device connected to the antenna device. This antenna device is installed such that the main axis of a radiation beam passes through the boundary between the inner peripheral surface of the underground space and a support, or between the outer peripheral surface of the support and the ground. 
     Patent Document 1: PCT International Publication No. WO2015/156096 
     Patent Document 2: PCT International Publication No. WO2019/039598 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     When a wireless communication device buried in the ground is exposed to, or submerged in, water such as rainwater, the wireless communication device may be affected by the water resulting in a risk of degradation of the radio wave characteristics and a risk of failure of the wireless communication device. However, Patent Document 1 does not disclose a configuration for draining water such as rainwater. Patent Document 2 discloses a configuration in which drain holes are formed in the bottom of the manhole where the antenna device is housed. However, this is not considered to be a sufficient drainage structure, and there is concern that water may accumulate in the manhole and come into contact with the antenna device. 
     In view of the foregoing circumstances, it is an object of the present invention to provide a housing unit capable of effectively reducing or preventing degradation of radio wave characteristics of a wireless communication device and failure of the wireless communication device, which can be caused by adverse effects of water. 
     Means for Solving the Problems 
     A first aspect of the present invention is directed to a housing unit including resin containers for housing a cable. The resin containers include: a first resin container configured to house a wireless communication device to which the cable is connected; and a second resin container configured to be disposed in front of or behind the first resin container in a direction in which the cable extends, and having an interior space that is adapted to communicate with an interior space of the first resin container. The first resin container includes a drain portion having a crest and a height varying portion, the crest being at a height greater than that of a boundary portion between the first resin container and the second resin container, the height varying portion decreasing in height throughout from the crest to the boundary portion. The second resin container includes a drain water-receiving portion that receives drain water from the drain portion, the drain water-receiving portion being at a height less than that of the boundary portion. 
     A second aspect of the present invention is an embodiment of the first aspect. In the second aspect, the first resin container further includes a first container body and a first lid, the first container body having a first bottom and a first opening that opens upward, the first lid closing the first opening of the first container body. The second resin container further includes a second container body and a second lid, the second container body having a second bottom and a second opening that opens upward, the second lid closing the second opening of the second container body. In a state where the second resin container is disposed in front of or behind the first resin container in the direction in which the cable extends, the boundary portion is provided between the first bottom and the second bottom. The first bottom has the drain portion, and the second bottom has the drain water-receiving portion. 
     A third aspect of the present invention is an embodiment of the first aspect. In the third aspect, the first resin container further includes a first container body and a first lid, the first container body having a first bottom and a first opening that opens upward, the first lid closing the first opening of the first container body. The second resin container further includes a second container body and a second lid, the second container body having a second bottom and a second opening that opens upward, the second lid closing the second opening of the second container body. In a state where the second resin container is disposed in front of or behind the first resin container in the direction in which the cable extends, the boundary portion is provided between the first lid and the second lid. The first lid has the drain portion, and the second lid has the drain water-receiving portion. 
     A fourth aspect of the present invention is an embodiment of the second aspect. In the fourth aspect, the wireless communication device is placed on the crest of the drain portion. 
     A fifth aspect of the present invention is an embodiment of the second or third aspect. In the fifth aspect, the first resin container further includes a support that is spaced upwardly from the first bottom, and the wireless communication device is supported by the support while being housed in a waterproof case. 
     A sixth aspect of the present invention is an embodiment of the second or third aspect. In the sixth aspect, the first lid has a housing chamber configured to house and seal the wireless communication device in a liquid-tight manner, and the wireless communication device is housed in the housing chamber. 
     Effects of the Invention 
     The present invention can effectively reduce or preventing degradation of the radio wave characteristics of the wireless communication device and failure of the wireless communication device, which can be caused by adverse effects of water. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram schematically illustrating a housing unit according to a first embodiment of the present invention and a road where the housing unit is installed; 
         FIG. 2  is a schematic diagram illustrating a wireless communication system including a wireless communication device according to the first embodiment; 
         FIG. 3  is a front cross-sectional view of the housing unit according to the first embodiment, taken along arrows in  FIG. 4 ; 
         FIG. 4  is a cross-sectional view taken along arrows IV-IV in  FIG. 3 ; 
         FIG. 5  is a front cross-sectional view of a housing unit according to a second embodiment of the present invention, taken along arrows V-V in  FIG. 6 ; 
         FIG. 6  is a cross-sectional view taken along arrows VI-VI in  FIG. 5 ; 
         FIG. 7  illustrates a first modification of the first embodiment, and is a side cross-sectional view of a first resin container; 
         FIG. 8  illustrates a second modification of the first embodiment, and is a side cross-sectional view of a first resin container; and 
         FIG. 9  illustrates a third modification of the first embodiment, and is a side cross-sectional view of a first resin container. 
     
    
    
     PREFERRED MODE FOR CARRYING OUT THE INVENTION 
     Embodiments of the present invention will be described below with reference to the drawings.  FIG. 1  is a diagram schematically illustrating a housing unit  1 A according to the present invention. The housing unit  1 A includes resin containers for housing cables. The cables include, for example, a power transmission cable (a power line  7  to be described later) that transmits electric power to households, etc., and a communication transmission cable (a communication line  6  to be described later) that transmits information. The housing unit  1 A includes a plurality first resin containers  10  that have a polygonal tubular shape and are arranged at predetermined intervals in a gutter  3  of a road  2 , and a plurality of second resin containers  20  that have a polygonal tubular shape and are disposed between the first resin containers  10 . As will be described in detail later, the first resin container  10  houses a wireless base station to which the cables are connected. The housing unit  1 A is laid such that each first resin container  10  is disposed at a location where the wireless base station is to be installed and each second resin container  20  is disposed in front of or behind the associated first resin container  10  in a direction in which the cables extend (on one side or the opposite side of the first resin container  10  in the direction in which the cables extend). 
     The housing unit  1 A may also include one or more third resin containers (not illustrated). The third resin container has a bottom and a lid that are substantially horizontal (flat) and is not provided with a drain portion or a drain water-receiving portion that will be described in detail later. In the housing unit  1 A having this configuration, one second resin container  20  is disposed while having its one end positioned in front of or behind the associated first resin container  10  in the direction in which the cables extend, and one third resin container  30  is disposed while having its one end positioned adjacent to the other end of the one second resin container  20 . In a case where the housing unit  1 A includes one first resin container  10  and a next first resin container  10  that are arranged with a large spacing therebetween, two or more third resin containers are arranged adjacent to each other between one second resin container  20  disposed in front of or behind the one first resin container  10  and a next second resin container  20  disposed in front of or behind the next first resin container  10 . 
     The plurality of resin containers  10  and  20  are arranged in a continuous manner such that their interior spaces communicate with each other. As a result, an elongated tunnel-like underground space  5  is formed inside the plurality of resin containers  10  and  20 . In the underground space  5 , the cables (the communication line  6  and the power line  7  illustrated in  FIG. 1 ) are laid. 
     Each first resin container  10  houses a wireless base station  8 . In other words, a plurality of wireless base stations  8  are distributed at regular intervals along the gutter  3 . The wireless base station  8  is an example of a wireless communication device according to the present invention, and is a device that transmits and receives communication radio waves to and from mobile communication terminals, such as cell phones. The wireless base station  8  is, for example, a base station for 5G (the fifth generation mobile communication system), but is not limited to the base station for 5G. For example, the first resin containers  10  are arranged at positions where the wireless base stations  8  housed in the first resin containers  10  complement each other in terms of the wireless transmission/reception range. 
     As illustrated in  FIG. 2 , the wireless base station  8  has a body  8   a  and an antenna  8   b . The body  8   a  of the wireless base station  8  housed in the first resin container  10  is connected to the communication line  6  via a communication branch line  6   a  and to the power line  7  via a power branch line  7   a . The communication line  6  is connected to a base station body (exchange)  9 . The wireless base stations  8  are connected to the base station body  9  via the communication branch lines  6   a  and the communication line  6 . The above-mentioned mobile communication terminals are wirelessly and communicatively connected to the base station body  9  via the wireless base stations  8 . The wireless base stations  8  are supplied with drive power from the power line  7  via the power branch lines  7   a.    
     First Embodiment 
     The first embodiment of the housing unit  1 A will be described below. Note that the drawings that will be referred to in the following description illustrate the wireless base station  8  in such a manner that the antenna  8   b , which is illustrated in  FIG. 2 , is omitted while the body  8   a  is illustrated as the wireless base station  8 . 
     As illustrated in  FIGS. 3 and 4 , the housing unit  1 A according to the first embodiment includes a first resin container  10  having a polygonal tubular shape and housing the wireless base station  8 , and second resin containers  20  disposed adjacent to the two opposing ends of the first resin container  10 . The first resin container  10  and the second resin containers  20  are arranged in a gutter  3  of a road  2  and are buried in the ground  4 , as illustrated in  FIG. 1 . As described above, the interior spaces of the resin containers  10  and  20  communicate with each other to form an elongated tunnel-like underground space  5  in which a communication line  6  and a power line  7  are laid. 
     The first resin container  10  has a first container body  11  and a first lid  16 . The first container body  11  and the first lid  16  are each a one-piece molding made of a predetermined resin material. 
     The first container body  11  has the shape of a so-called U-shaped groove and has a first bottom  12 , a pair of side walls  13 ,  13 , and a first opening  14  that opens upward. 
     As illustrated in  FIG. 4 , the first bottom  12  has one end  12   a  and the other end  12   b  that face the adjacent second resin containers  20 , respectively. The first bottom  12  has the shape of an arch that curves upward convexly throughout from the one end  12   a  to the other end  12   b . The first bottom  12  has a drain portion  15  on its upper surface. 
     The drain portion  15  has a crest  15   c  that is the highest part of the drain portion  15 , a curved surface  15   a  that gradually decreases in height throughout from the crest  15   c  to the one end  12   a , and a curved surface  15   b  that gradually decreases in height throughout from the crest  15   c  to the other end  12   b . The curved surfaces  15   a  and  15   b  curve from the crest  15   c  to the one end  12   a  and the other end  12   b , respectively, while constantly decreasing in height. The curved surfaces  15   a  and  15   b  are each an example of a height varying portion of the present invention. 
     As illustrated in  FIG. 4 , the wireless base station  8  is disposed on the crest  15   c  of the drain portion  15 . The wireless base station  8  is held stably on the crest  15   c  using a fastening member such as a fixing device or a screw. 
     The first lid  16  is a plate-like member that closes the first opening  14  of the first container body  11 . The first lid  16  is made of a resin having radio wave permeability. The first lid  16  is detachably attached to the first container body  11  using a fastening means such as a metal fastener or a rubber band. 
     As illustrated in  FIG. 4 , the second resin containers  20  are disposed adjacent to the two opposing ends of the first resin container  10  and each include a second container body  21  and a second lid  26 . The second container body  21  and the second lid  26  are each a one-piece molding made of a predetermined resin material. 
     The second container body  21  has the shape of a so-called U-shaped groove and has a second bottom  22 , a pair of side walls  23 ,  23  (only one of which is illustrated in  FIG. 4 ), and a second opening  24  that opens upward. The second bottom  22  has one end  22   a  and the other end  22   b  that face the adjacent first resin container  10 . 
     The second bottom  22  curves concavely throughout from the one end  22   a  to the other end  22   b . The second bottom  22  has a drain water-receiving portion  25  on its upper surface. The drain water-receiving portion  25  has a concave shape to receive water (drain water) flowing down from the drain portion  15  of the first resin container  10 . The drain water-receiving portion  25  is constituted by the upper surface of the second bottom  22  that curves concavely. 
     The second lid  26  is a plate-like member that closes the second opening  24  of the second container body  21 . The second lid  26  is detachably attached to the second container body  21  using a fastening means such as a metal fastener or a rubber band. 
     The housing unit  1 A according to the first embodiment is arranged in the gutter  3  illustrated in  FIG. 1  such that the second resin containers  20  are disposed adjacent to the two opposing ends of the first resin container  10 . The first resin container  10  and the second resin containers  20  are disposed adjacent to each other such that each of the opposing ends of one container faces a corresponding one of the opposing ends of the adjacent container. The first resin container  10  and the second resin containers  20  may be connected to each other with joint members. 
     As illustrated in  FIG. 4 , the housing unit  1 A according to the first embodiment has a boundary portion  31  between the end  12   a  of the first bottom  12  of the first resin container  10  and the end  22   b  of the second bottom  22  of the second resin container  20 . Further, the housing unit  1 A has a boundary portion  32  between the end  12   b  of the first bottom  12  of the first resin container  10  and the end  22   a  of the second bottom  22  of the second resin container  20 . 
     The crest  15   c  of the drain portion  15  of the first resin container  10  is at a height greater than the height of the boundary portion  31  and the height of the boundary portion  32 . The curved surfaces  15   a  and  15   b  of the drain portion  15  gradually decrease in height throughout from the crest  15   c  to the boundary portion  31  and the boundary portion  32 , respectively. The drain water-receiving portions  25  of the second resin containers  20  are at a height less than those of the boundary portions  31  and  32 , whereby drain water that has flowed along the curved surfaces  15   a  and  15   b  of the drain portion  15  and reached the boundary portions  31  and  32  is allowed to cross the boundary portions  31  and  32  and flow into the drain water-receiving portions  25 . 
     Effects exerted by the housing unit  1 A according to the first embodiment are described below. The housing unit  1 A according to the first embodiment includes the tubular first resin container  10  configured to be buried in the ground  4  and to house the wireless base station  8 , and the tubular second resin containers  20  configured to be buried in the ground  4  and to be disposed adjacent to the first resin container  10 , and having the interior spaces communicating with the interior space of the first resin container  10 . The first resin container  10  includes the drain portion  15  having the crest  15   c  that is at a height greater than the height of the boundary portions  31  and  32  between the first resin container  10  and the second resin containers  20 , and the curved surfaces  15   a  and  15   b  that gradually decrease in height throughout from the crest  15   c  to the boundary portions  31  and  32 . Each second resin container  20  has the drain water-receiving portion  25  that is at a height less than the height of the boundary portions  31  and  32  and receives drain water from the drain portion  15 . 
     Specifically, the first resin container  10  includes the first container body  11  having the first bottom  12  and the first opening  14  that opens upward, and includes the first lid  16  closing the first opening  14  of the first container body  11 . The second resin containers  20  each include the second container body  21  having the second bottom  22  and the second opening  24  that opens upward, and includes the second lid  26  closing the second opening  24  of the second container body  21 . The boundary portions  31  and  32  are provided between the first bottom  12  and the second bottoms  22 . The first bottom  12  has the drain portion  15 , and each second bottom  22  has the drain water-receiving portion  25  that receives drain water from the drain portion  15 . The wireless base station  8  is placed on the crest  15   c  of the drain portion  15  of the first resin container  10 . 
     According to the first embodiment, when water, such as rainwater, passes between the first container body  11  and the first lid  16  of the first resin container  10  and enters the first container body  11 , the water flows down the inner surfaces of the side walls  13  to reach the drain portion  15  on the first bottom  12 . After reaching the drain portion  15 , the water flows down the curved surface  15   a  or  15   b , crosses the boundary portion  31  or  32  to be drained into the second resin container  20 . The water that has been drained into the second resin containers  20  flows into the drain water-receiving portion  25  to be stored there. Part of the water passes through the boundary portions  31  and  32  to penetrate the ground  4 , without crossing the boundary portions  31  and  32 . 
     Water that has entered the first resin container  10  is always drained from the drain portion  15  to the drain water-receiving portions  25  of the second resin containers  20 , thereby preventing or reducing the accumulation of water in the first resin container  10 . Thus, according to the first embodiment, the first resin container  10  in which the wireless base station  8  is housed has sufficient drainage, and is effective in making it unlikely for the wireless base station  8  to be submerged in water in the first resin container  10 . 
     The first resin container  10  and the second resin containers  20  of the present embodiment may have one or more holes in the respective side wall  13  and side wall  26 , or the respective bottom  12  and bottom  22 . In that case, the holes also allow water that has entered the first resin container  10  and the second resin containers  20  to be discharged to the outside (into the ground  4 ). 
     Second Embodiment 
     Next, a housing unit  1 B according to a second embodiment of the present invention will be described with reference to  FIGS. 5 and 6 . In the drawings that will be referred to in the description of the second embodiment, the same elements as those of the first embodiment are denoted by the same reference characters. A description of the same elements will be omitted, while differences from the first embodiment will be described. 
     As shown in  FIGS. 5 and 6 , a first resin container  10  according to the second embodiment includes a container body  11  having a flat bottom  12 , and second resin containers  20  according to the second embodiment each include a container body  21  having a flat bottom  22 . The first bottom  12  does not have the drain portion  15  and the second bottom  22  does not have the drain water-receiving portion  25 . A wireless base station  8  is placed on the flat first bottom  12 . 
     As illustrated in  FIG. 5 , the first resin container  10  according to the second embodiment has a first lid  16  that includes a top plate  17  and a pair of side walls  18 . As illustrated in  FIG. 6 , the top plate  17  has one end  17   a  and the other end  17   b  that face the adjacent second resin containers  20 , respectively. The top plate  17  of the first lid  16  has the shape of an arch that curves upward convexly throughout from the one end  17   a  to the other end  17   b . The top plate portion  17  has a drain portion  19  on its upper surface. 
     The drain portion  19  has a crest  19   c  that is the highest part, a curved surface  19   a  that gradually decreases in height throughout from the crest  19   c  to the one end  17   a , and a curved surface  19   b  that gradually decreases in height throughout from the crest  19   c  to the other end  17   b . The curved surfaces  19   a  and  19   b  curve from the crest  19   c  to the one end  17   a  and the other end  17   b , respectively, while constantly decreasing in height. The curved surfaces  19   a  and  19   b  are each an example of the height varying portion of the present invention. 
     As shown in  FIG. 6 , each second resin container  20  according to the second embodiment has a second lid  26  having one end  26   a  and the other end  26   b  that face the adjacent first resin container  10 . The second lid  26  has an upper surface that curves concavely throughout from the one end  26   a  to the other end  26   b . The second lid  26  has a drain water-receiving portion  27  on its upper surface. 
     The drain water-receiving portion  27  is a concave portion that receives water (drain water) flowing down from the drain portion  19  of the first lid  16  of the first resin container  10 . The drain water-receiving portion  27  is constituted by the upper surface of the second lid  26  that curves concavely. 
     The housing unit  1 B according to the second embodiment has a boundary portion  41  between the end  17   a  of the top plate  17  forming part of the first lid  16  of the first resin container  10  and the end  26   b  of the second lid  26  of the second resin container  20 . Further, the housing unit  1 B has a boundary portion  42  between the end  17   b  of the top plate  17  forming part of the first lid  16  of the first resin container  10  and the end  26   a  of the second lid  26  of the second resin container  20 . 
     The crest  19   c  of the drain portion  19  of the first resin container  10  is at a height greater than the height of the boundary portion  41  and the height of the boundary portion  42 . The curved surface  19   a  and the curved surface  19   b  of the drain portion  19  gradually decrease in height throughout from the crest  19   c  to the boundary portion  41  and the boundary portion  42 , respectively. The drain water-receiving portions  27  of the second resin containers  20  are at a height less than those of the boundary portions  41  and  42 , whereby drain water that has flowed along the curved surfaces  19   a  and  19   b  of the drain portion  19  and reached the boundary portions  41  and  42  is allowed to cross the boundary portions  41  and  42  and flow into the drain water-receiving portions  27 . 
     Effects exerted by the housing unit  1 B according to the second embodiment are described below. In the housing unit  1 B according to the second embodiment, the first resin container  10  includes the first container body  11  having the first bottom  12  and the first opening  14  that opens upward, and includes the first lid  16  closing the first opening  14  of the first container body  11 . The second resin containers  20  each include the second container body  21  having the second bottom  22  and the second opening  24  that opens upward, and includes the second lid  26  closing the second opening  24  of the second container body  21 . The boundary portion  41  and the boundary portion  42  are provided between the first lid  16  and the second lids  26 . The first lid  16  has the drain portion  19 , and each second lid  26  has the drain water-receiving portion  27  that receives drain water from the drain portion  19 . 
     According to the second embodiment, when it is raining, for example, the drain portion  19  on the first lid  16  receives rainwater. The rainwater or other water received by the drain portion  19  flows down the curved surfaces  19   a  and  19   b  and crosses the boundary portions  41  and  42  to be drained onto the second lids  26  of the second resin containers  20 , and then, flows into the drain water-receiving portions  27  to be stored there. Part of the water falls through gaps between the first lid  16  of the first resin container  10  and the second lids  26  of the second resin containers  20  without crossing the boundary portions  41  and  42 , and penetrates the ground  4 . 
     As can be seen, water falling onto the first lid  16  of the first resin container  10  is drained from the drain portion  19  of the first resin container  10  to the drain water-receiving portions  27  of the second resin containers  20 , thereby reducing or preventing the accumulation of water in the first resin container  10 . Thus, according to the second embodiment, the first resin container  10  in which the wireless base station  8  is housed has sufficient drainage, and is effective in making it unlikely for the wireless base station  8  to be submerged in water in the first resin container  10 . 
     Accumulation of water on the first lid  16  may cause a change in permittivity and affect the radio wave characteristics transmitted and received by the wireless base station  8  installed below the first lid  16 . To address this, the drain portion  19  of the second embodiment can prevent water from accumulating above the wireless base station  8 . This feature makes it unlikely for puddles to form on the first lid  16  even when it rains, and allows stable radio wave characteristics to be obtained. 
     &lt;Modifications&gt; 
     Next, three modifications (first to third modifications) of the above-described first embodiment will be described with reference to  FIGS. 7 to 9 . The following modifications differ from the first embodiment in the way in which the wireless base station  8  is housed in the first resin container  10 . 
       FIG. 7  illustrates the first modification. According to the first modification, the first container body  11  of the first resin container  10  has a support  51  that is spaced upwardly from the first bottom  12 . The support  51  includes a plurality of legs  51   a . The support  51  is fixed to the drain portion  15  of the first bottom  12 . On top of the support  51 , a waterproof case  52  is provided and integrated with the support  51 . The wireless base station  8  is housed and sealed in the waterproof case  52  in a liquid-tight manner. 
     In the first modification, the wireless base station  8  is housed in the waterproof case  52  and supported by the support  51  at a position spaced upwardly from the drain portion  15 . This configuration makes it unlikely for the wireless base station  8  to be submerged in water in the first container body  11 , and can prevent the wireless base station  8  from coming into contact with water that has entered the first resin container  10 . 
       FIG. 8  illustrates the second modification. According to the second modification, a waterproof case  52  that houses the wireless base station  8  is fixed to the back surface of the first lid  16 . In this modification, the first lid  16  forms a support  51  that is spaced upwardly from the first bottom  12 . 
     In the second modification, the wireless base station  8  is supported at a position spaced upwardly from the drain portion  15  by being housed in the waterproof case  52  fixed to the back surface of the first lid  16 . This configuration makes it unlikely for the wireless base station  8  to be submerged in water in the first container body  11 , and can prevent the wireless base station  8  from coming into contact with water that has entered the first resin container  10 . In addition, since the first lid  16  also serves as the support by which the wireless base station  8  is spaced upwardly from the first bottom  12 , the support  51  as in the first modification described above can be omitted, thereby reducing an increase in the number of the components. 
       FIG. 9  illustrates the third modification. The first lid  16  of the third modification has a housing chamber  53  that opens upward. The housing chamber  53  is liquid-tightly sealed with a lid part  54  that is detachably attached to the first lid  16 . The wireless base station  8  is housed in the housing chamber  53 . 
     According to the third modification, the wireless base station  8  is housed in the housing chamber  53  of the first lid  16  in a liquid-tight manner. This configuration makes it unlikely for the wireless base station  8  to be submerged in water in the first container body  11 , and can prevent the wireless base station  8  from coming into contact with water that has entered the first resin container  10 . 
     It should be noted that the above-described embodiments and modifications of the present invention are not intended to limit the present invention, and appropriate variations may be made to the present invention. For example, the container bodies  11  and  21  of the first embodiment may be combined with the second embodiment such that not only the lids but also the container bodies are provided with the respective drain portions and drain water-receiving portions. Further, the first to third modifications illustrated in  FIGS. 7 to 9  may be applied to the second embodiment. 
     EXPLANATION OF REFERENCE NUMERALS 
     
         
           1 A,  1 B: Housing unit 
           4 : Ground 
           6 : Communication line (Cable) 
           7 : Power line (Cable) 
           8 : Wireless base station (Wireless communication device) 
           10 : First resin container 
           11 : First container body 
           12 : First bottom 
           14 : First opening 
           15 ,  19 : Drain portion 
           15   a ,  15   b ,  19   a ,  19   b : Curved surface (Height varying portion) 
           15   c ,  19   c : Crest 
           16 : First lid 
           20 : Second resin container 
           21 : Second container body 
           22 : Second bottom 
           24 : Second opening 
           25 ,  27 : Drain water-receiving portion 
           26 : Second lid 
           31 ,  32 ,  41 ,  42 : Boundary portion 
           51 : Support 
           52 : Waterproof case 
           53 : Housing chamber