Patent Publication Number: US-2023139400-A1

Title: Automated Warehouse

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-178753 filed Nov. 1, 2021, the disclosure of which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an automated warehouse that includes a storage rack capable of storing a plurality of articles and a transport apparatus configured to travel along a front face of the storage rack and transport the articles. 
     2. Description of the Related Art 
     WO 2015/052998 discloses an example of such an automated warehouse. In the following description of the related art, reference numerals or names shown in parentheses are those used in WO 2015/052998. 
     The automated warehouse described in WO 2015/052998 includes a storage rack (stocker  2 ) for storing articles, a drawer unit ( 4 ) configured to be capable of being inserted into and drawn out from the storage rack (stocker  2 ), and a transport apparatus ( 50 ). The drawer unit ( 4 ) includes a plurality of placement sections (shelves  14 ) for placing containers, which are next to each other in an up-down direction. That is, the drawer unit ( 4 ) serves as a portion of the storage rack (stocker  2 ) to store articles. Also, the drawer unit ( 4 ) is configured to be drawn out from a back face of the storage rack (stocker  2 ) to open an entrance to the inside of the storage rack (stocker  2 ) for workers. 
     The above-described configuration of the automated warehouse allows a worker to draw out the drawer unit ( 4 ) from the back face of the storage rack (stocker  2 ) to take out an article placed on a placement section (shelf  14 ) of the drawer unit ( 4 ) in a case where the transport apparatus ( 50 ) cannot be operated due to a power failure or breakdown, for example. However, the plurality of placement sections (shelves  14 ) are arranged in the up-down direction, and accordingly, the worker is obstructed by a placement section (shelf  14 ) right above the article to be taken out, and it is not easy for the worker to take out the article particularly in a case where the article is heavy. On the other hand, in order to make it easy for the worker to take out the article, the distance in the up-down direction between the article placed on the placement section (shelf  14 ) and the placement section (shelf  14 ) right above the article needs to be made larger than a distance necessary for the worker to lift the article. Accordingly, the distance between the plurality of placement sections (shelves  14 ) in the up-down direction is likely to be large, which causes a reduction in an efficiency of storing articles in the automated warehouse. 
     SUMMARY OF THE INVENTION 
     Therefore, in view of the foregoing, there is demand for realizing an automated warehouse that makes it easy for workers to take out an article from the back face side of the storage rack while avoiding a reduction in the efficiency of storing articles. 
     An automated warehouse according to the present disclosure is characterized in including: a storage rack configured to store a plurality of articles; and a transport apparatus configured to travel along a front face of the storage rack and transport the articles, wherein the storage rack includes: a plurality of placement sections on which the articles are placeable; a frame member supporting the plurality of placement sections; and a cover, the cover covers a back face of the storage rack, the plurality of placement sections are next to each other in both an up-down direction and a width direction orthogonal to the up-down direction as viewed in a depth direction that is a direction from the front face toward the back face or from the back face toward the front face, and storage regions in which the articles are storable are respectively formed between pairs of two placement sections adjacent to each other in the up-down direction, the automated warehouse further includes at least one placement section module including at least one placement section, the at least one placement section including one of the placement sections or a plurality of the placement sections adjacent to each other in the width direction, the at least one placement section module is supported by the frame member via a slide mechanism, the slide mechanism supports the at least one placement section module in such a manner that the at least one placement section module is slidable relative to the frame member between a reference position and a protruding position that is on a back face side in the depth direction relative to the reference position, the back face side in the depth direction being the back face side as seen from the front face side in the depth direction, when the at least one placement section module is at the reference position, the at least one placement section is on a front face side in the depth direction relative to a frame member back surface that is a surface of the frame member on the back face side in the depth direction, the front face side in the depth direction being the front face side as seen from the back face side in the depth direction, when the at least one placement section module is at the protruding position, the at least one placement section protrudes from the frame member back surface toward the back face side in the depth direction, the cover includes a cover member covering a face of the at least one placement section module on the back face side in the depth direction, and the at least one placement section module is configured in such a manner that an upper side of the storage regions is exposed in a state where the at least one placement section module is at the protruding position. 
     According to this configuration, when the placement section module is slid to the protruding position, articles can be easily taken out from the upper side of the placement section module. Also, when the placement section module is at the reference position, the back face of the storage rack can be covered with the cover including the cover member. 
     As described above, the automated warehouse is configured to take out articles from the upper side of the placement section module in the state where the placement section module has been slid to the protruding position, and therefore, a worker can easily take out articles when compared with a case where the cover covering the back face of the plurality of placement sections is merely removed to take out articles in the depth direction. Moreover, there is no need to make the distance between the plurality of placement sections in the up-down direction large in order to make it easy for the worker to take out articles as in the case where articles are taken out in the depth direction, and therefore, it is easy to increase the efficiency of storing articles in the storage rack. 
     Further features and advantages of the automated warehouse will be clarified by exemplary and non-limiting embodiments described below with reference to the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a cross section of an automated warehouse viewed in a width direction. 
         FIG.  2    is a partial enlarged view of a back face of a storage rack. 
         FIG.  3    is a plan view of a placement section module at a protruding position. 
         FIG.  4    is a plan view of the placement section module at a reference position. 
         FIG.  5    is a partial enlarged view showing a positional relationship between the placement section module and back-face-side frame portions viewed in a depth direction. 
         FIG.  6    shows a cross section of a slide mechanism viewed in the depth direction. 
         FIG.  7    is a side view of the placement section module at the protruding position and the slide mechanism. 
         FIG.  8    is a perspective view of a placement section module at the reference position and a placement section module at the protruding position. 
         FIG.  9    is a control block diagram. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     1. Automated Warehouse 
     First, an embodiment of an automated warehouse  1  will be described based on the drawings. As shown in  FIG.  1   , the automated warehouse  1  includes a storage rack  2  capable of storing a plurality of articles W and a transport apparatus  4  configured to travel along a front face  2 A of the storage rack  2  and transport articles W. In the illustrated example, the automated warehouse  1  includes a pair of storage racks  2  facing each other with the transport apparatus  4  located therebetween. In this example, the articles W are FOUPs (Front Opening Unified Pods) for storing semiconductor substrates (wafers). 
     The following describes each configuration of the automated warehouse  1 . As shown in  FIGS.  1  and  2   , a direction from the front face  2 A toward a back face  2 B of each of the pair of storage racks  2  or from the back face  2 B toward the front face  2 A will be referred to as a “depth direction X”. A direction orthogonal to an up-down direction Z as viewed in the depth direction X will be referred to as a “width direction Y”. The front face  2 A side as seen from the back face  2 B side in the depth direction X will be referred to as a “front face side X1 in the depth direction”, and the back face  2 B side as seen from the front face  2 A side in the depth direction X will be referred to as a “back face side X2 in the depth direction”. 
     2. Transport Apparatus 
     The transport apparatus  4  in the present embodiment includes a transfer device  83  as shown in  FIG.  1   . The transfer device  83  holds an article W and transfers the article W between a placement section  10  of the storage racks  2  and the transfer device  83 . The transport apparatus  4  moves the transfer device  83  along the front face  2 A of each storage rack  2  in both the width direction Y and the up-down direction Z to transport articles W along the front face  2 A of the storage rack  2 . In this example, the transport apparatus  4  includes, in addition to the transfer device  83 , an aisle  5  extending in the width direction Y along the front face  2 A of each storage rack  2 , a cart  80  configured to travel along the aisle  5 , a support  81  fixed to the cart  80 , and an elevation body  82  that supports the transfer device  83  and ascends and descends along the support  81  in the up-down direction Z. The cart  80  moves along the width direction Y while being guided by a rail R installed along the aisle  5 . As described above, the transport apparatus  4  in this example is a stacker crane. Also, the transport apparatus  4  receives an article W from any placement section  10  of the storage racks  2  whose front faces  2 A are facing the aisle  5 , and transports the article W to a carry-out port (not shown) for transporting articles W to the outside of the storage racks  2 . Also, the transport apparatus  4  receives an article W from a carry-in port (not shown) for transporting articles W from the outside of the storage racks  2 , and transports the article W to any placement section  10  of the storage racks  2 . 
     The transfer device  83  is configured to be capable of transferring an article W to any placement section  10  of the pair of storage racks  2  disposed on both sides of the aisle  5  in the depth direction X. Specifically, the transfer device  83  transfers articles W by moving the articles W between the transfer device  83  and transfer target places such as a plurality of placement sections  10  included in the storage racks  2 . As described above, the transfer target places for the transfer device  83  include the carry-in port for transporting articles W from the outside of the storage racks  2  and the carry-out port for transporting articles W to the outside of the storage racks  2 , in addition to the placement sections  10 . In the present embodiment, the transfer device  83  includes a transport support portion  84  configured to support an article W and protrude and retract in the depth direction X. 
     In this example, the transport support portion  84  is configured to support an article W from below. More specifically, the transport support portion  84  includes a plurality of transport protrusions (not shown) that engage with to-be-engaged portions (not shown) of an article W from below, and is configured to support a bottom surface of the article W from below in a state where the plurality of transport protrusions engage with the to-be-engaged portions of the article W from below. In this example, the transfer device  83  is a slide fork-type transfer device. 
     3. Storage Rack 
     Each storage rack  2  includes a plurality of placement sections  10  on which articles W are placeable, a frame member  6  supporting the plurality of placement sections  10 , and a cover  3 . In the present embodiment, each storage rack  2  further includes placement section accessory members  30  corresponding to the respective placement sections  10 . As shown in  FIG.  1   , the front face  2 A of each of the pair of storage racks  2  is on the aisle  5  side and extends along the up-down direction Z and the width direction Y adjacent to the aisle  5 . In this example, the pair of storage racks  2  are disposed on both sides of the aisle  5  in the depth direction X. Also, the front faces  2 A of the pair of storage racks  2  face each other. In the illustrated example, the automated warehouse  1  further includes an airflow generating device D (see  FIG.  1   ). The pair of storage racks  2  are below the airflow generating device D. The airflow generating device D generates an airflow (downflow) flowing from the upper side toward the lower side in the area in which the storage racks  2  and the transport apparatus  4  are present. 
     3-1. Placement Section 
     As shown in  FIGS.  1  and  2   , the plurality of placement sections  10  are next to each other in both the up-down direction Z and the width direction Y, and storage regions S in which articles W are storable are respectively formed between pairs of two placement sections  10  adjacent to each other in the up-down direction Z. In the present embodiment, each of the plurality of placement sections  10  is supported by the frame member  6  in a cantilever manner from the back face side X2 in the depth direction. Each of the plurality of placement sections  10  is configured to allow an article W to be placed in and taken out from the corresponding storage region S from the front face side X1 in the depth direction. In this example, some placement sections  10  among the plurality of placement sections  10  are supported by the frame member  6  via slide mechanisms  40 , which will be described later. The remaining placement sections  10  are directly supported by the frame member  6 . In the following description, a region in which the placement sections  10  supported by the frame member  6  via the slide mechanisms  40  are located will be referred to as a specific region  34 . A region in which the placement sections  10  directly supported by the frame member  6  are located will be referred to as a general region  35 . In the illustrated example, out of the plurality of placement sections  10  arranged in the up-down direction Z, placement sections  10  located in a plurality of rows including the bottom row (in this example, the first through fourth rows as counted from the bottom) are supported by the frame member  6  via the slide mechanisms  40 , and placement sections  10  located in higher rows are directly supported by the frame member  6 . That is, in the illustrated example, the region in which the placement sections  10  in the first through fourth rows as counted from the bottom are located is the specific region  34 , and the region in which the placement sections  10  in higher rows are located is the general region  35 . 
     As shown in  FIGS.  3 ,  4 , and  7   , in the present embodiment, each of the plurality of placement sections  10  includes a support body  12  configured to support a stored article W from below and a fixed portion  11  that is fixed to a support member  18  of a placement section module  20 , which will be described later, or the frame member  6 . Here, the support body  12  and the fixed portion  11  are formed as a single piece and constituted by the same member. The support body  12  includes a plurality of storage protrusions P that engage with to-be-engaged portions (not shown) of the article W from below (see  FIG.  3   ). The support body  12  is configured to support the bottom surface of the article W from below in a state where the storage protrusions P engage with the to-be-engaged portions of the article W from below. 
     3-2. Frame Member 
     Next, the frame member  6  will be described. In this example, the configuration of the frame member  6  differs between the general region  35  and the specific region  34 . First, the frame member  6  in the general region  35  will be described. As shown in  FIGS.  1  and  2   , the frame member  6  includes a plurality of front-face-side supports  14 , a plurality of back-face-side supports  15 , a plurality of beams  17 , and a plurality of connecting beams  21 . The plurality of back-face-side supports  15  are disposed separately from each other in the width direction Y on the back face side X2 in the depth direction relative to the plurality of storage regions S. The plurality of front-face-side supports  14  are disposed separately from each other in the width direction Y on the front face side X1 in the depth direction relative to the plurality of storage regions S. Here, the positions of the front-face-side supports  14  in the width direction Y correspond to the back-face-side supports  15 . The plurality of connecting beams  21  are disposed separately from each other at a plurality of positions in the up-down direction Z. The connecting beams  21  extend along the depth direction X and connect the front-face-side supports  14  and the back-face-side supports  15  disposed at corresponding positions in the width direction Y. The plurality of beams  17  are disposed separately from each other at a plurality of positions in the up-down direction Z. The beams  17  extend along the width direction Y and connect a pair of back-face-side supports  15  adjacent to each other in the width direction Y. In the illustrated example, a pair of connecting beams  21  are disposed separately from each other in the up-down direction Z, and one of the connecting beams  21  connects an upper end portion of a back-face-side support  15  and an upper end portion of a corresponding front-face-side support  14 . The other connecting beam  21  connects a lower end portion of the back-face-side support  15  and a lower end portion of the corresponding front-face-side support  14  (see  FIG.  1   ). Also, in the illustrated example, each of the plurality of placement sections  10  in the general region  35  is supported by a beam  17 . Specifically, the placement section  10  is directly supported by the frame member  6  with the fixed portion  11  of the placement section  10  fixed to the beam  17  (see  FIG.  2   ). 
     Next, the following describes the frame member  6  in the specific region  34  focusing on configurations that differ from those of the frame member  6  in the general region  35 . As shown in  FIGS.  1 ,  2 , and  4   , the beams  17  are not provided in the specific region  34 . The frame member  6  in the specific region  34  includes a plurality of connecting members  47 . The plurality of connecting members  47  are disposed separately from each other at a plurality of positions in the up-down direction Z. The connecting members  47  extend along the depth direction X. The connecting members  47  each connect a back-face-side support  15  and a front-face-side support  14  disposed at corresponding positions in the width direction Y, and support a slide mechanism  40 . As described above, the frame member  6  in the general region  35  is not provided with the slide mechanisms  40 , but the frame member  6  in the specific region  34  is provided with the slide mechanisms  40 . 
     3-3. Placement Section Accessory Member 
     As shown in  FIGS.  5  and  7   , in the present embodiment, the placement section accessory members  30  are on the back face side X2 in the depth direction relative to storage regions S formed on the corresponding placement sections  10 , and overlap the storage regions S as viewed in the depth direction. Also, in this example, the placement section accessory members  30  are on the front face side X1 in the depth direction relative to the cover  3 . That is, the placement section accessory members  30  are located between the cover  3  and the storage regions S. In the illustrated example, each of the placement section accessory members  30  is fixed to the fixed portion  11  of the corresponding placement section  10  via a first bracket  29 . The placement section accessory member  30  and the first bracket  29  are fixed by being fastened with a first fastening member  31 . 
     In the illustrated example, the placement section accessory members  30  constitute an article detection sensor  32  for detecting the presence or absence of articles W placed on the placement sections  10 . Specifically, the placement section accessory members  30  are reflective plate portions constituting the article detection sensor  32 . That is, the placement section accessory members  30  cooperate with a light emitting/receiving portion  36  (see  FIG.  1   ) provided in the transfer device  83  and function as the article detection sensor  32 . Specifically, if no article W is placed on a placement section  10  that has been selected as a transfer target place in a state where the transfer device  83  is at a transfer preparation position corresponding to the placement section  10 , light emitted from the light emitting/receiving portion  36  reaches the corresponding placement section accessory member  30  (reflective plate portion), and light reflected off the placement section accessory member  30  is received by the light emitting/receiving portion  36 . Here, the placement section accessory member  30  is formed with use of a retroreflective material that reflects incident light toward a light source. On the other hand, if an article W is placed on the placement section  10  selected as the transfer target place, light emitted from the light emitting/receiving portion  36  is interrupted by the article W and does not reach the corresponding placement section accessory member  30 , and accordingly, the light emitting/receiving portion  36  does not receive light. The article detection sensor  32  detects the presence or absence of an article W placed on the placement section  10  based on whether or not the light emitting/receiving portion  36  receives reflected light. 
     3-4. Cover 
     As shown in  FIG.  1   , the cover  3  covers the back face  2 B of the storage rack  2 . In the present embodiment, the cover  3  covers an entirety of the back face  2 B of the storage rack  2 . The cover  3  is on the back face side X2 in the depth direction relative to the plurality of storage regions S. In the present embodiment, the cover  3  includes a fixed cover member  13 K and a plurality of cover members  13 , which will be described later. The fixed cover member  13 K is fixed to the frame member  6 . On the other hand, each of the plurality of cover members  13  is attached to a placement section module  20 , which will be described later, and is configured to slide in the depth direction X together with the placement section module  20  by means of the slide mechanisms  40 . On the other hand, the fixed cover member  13 K is fixed to the frame member  6  so as to cover a remaining portion of the back face  2 B in which the cover members  13  are not provided. That is, in this example, the plurality of cover members  13  are next to each other in the up-down direction Z and the width direction Y in the specific region  34  in which the slide mechanisms  40  are provided, and the fixed cover member  13 K is in the general region  35  in which the slide mechanisms  40  are not provided. 
     4. Placement Section Module and Slide Mechanism 
     As shown in  FIGS.  2  and  8   , the automated warehouse  1  includes the placement section module  20  that includes one placement section  10  or a plurality of placement sections  10  adjacent to each other in the width direction Y. In the present embodiment, the automated warehouse  1  includes a plurality of placement section modules  20 . Each of the plurality of placement section modules  20  includes a plurality of placement sections  10  adjacent to each other in the width direction Y. In this example, the plurality of placement section modules  20  include the same number of placement sections  10 . In the illustrated example, each placement section module  20  includes three placement sections  10  (see  FIG.  5   ). Here, the number of placement sections  10  included in one placement section module  20  is not limited to three, and may be two, or four or more. 
     As shown in  FIGS.  2  and  8   , in the present embodiment, the plurality of placement section modules  20  are arranged next to each other in the up-down direction Z. Furthermore, the plurality of placement section modules  20  are arranged side by side in the width direction Y as well. In this example, the placement section modules  20  are in the specific region  34 . When a plurality of placement section modules  20  next to each other in the up-down direction Z are collectively referred to as a placement section module group  20 T, a plurality of placement section module groups  20 T are arranged side by side in the width direction Y (see  FIG.  2   ). In the illustrated example, each of the plurality of placement section module groups  20 T includes placement sections  10  located in a plurality of rows including the bottom row (in this example, the first through fourth rows as counted from the bottom). Each row of each placement section module group  20 T includes a single placement section module  20 . 
     As shown in  FIGS.  2 ,  3 , and  7   , each placement section module  20  is supported by the frame member  6  via the slide mechanisms  40 . In the present embodiment, each placement section module  20  is supported by the frame member  6  via the slide mechanisms  40  in such a manner that the placement section module  20  is slidable in the depth direction X. The following describes specific configurations of the placement section module  20  and the slide mechanisms  40 . 
     As shown in  FIGS.  3 ,  4 , and  5   , in this example, each placement section module  20  includes a plurality of placement sections  10  and the support member  18  supporting the plurality of placement sections  10 . The support member  18  extends along the width direction Y and is supported by the connecting members  47  via the slide mechanisms  40 . The support member  18  is on the back face side X2 in the depth direction relative to the storage regions S. In the illustrated example, the support member  18  supports the plurality of (here, three) placement sections  10  arranged side by side in the width direction Y. The fixed portion  11  of each placement section  10  is fixed to the support member  18 . 
     Also, as shown in  FIGS.  3 ,  4 ,  6 , and  7   , in this example, the slide mechanisms  40  connect the placement section module  20  and the frame member  6  and guide the placement section module  20  in such a manner that the placement section module  20  is movable in the depth direction X relative to the frame member  6 . The slide mechanisms  40  are attached to the connecting members  47  and extend along the depth direction X. The slide mechanisms  40  are provided on both sides of the placement section module  20  in the width direction Y. The two slide mechanisms  40  on both sides in the width direction Y support the single placement section module  20 . As shown in  FIGS.  6  and  7   , in this example, each slide mechanism  40  includes a first slide rail portion  41  that is fixed to the connecting member  47 , a second slide rail portion  42  that is held by the first slide rail portion  41 , a slider portion  43  that is held by the second slide rail portion  42 , and a plurality of balls  44 . The second slide rail portion  42  is held by the first slide rail portion  41  in such a manner as to be movable in the depth direction X. The slider portion  43  is held by the second slide rail portion  42  in such a manner as to be movable in the depth direction X. The slider portion  43  is fixed to the placement section module  20 . More specifically, the slider portions  43  of the slide mechanisms  40  on both sides in the width direction Y are respectively fixed to two end portions of the support member  18  in the width direction Y. In the illustrated example, the slider portions  43  are fixed to the support member  18  via second brackets  48  (see  FIG.  6   ). The second brackets  48  are fixed to the support member  18  by being fastened with second fastening members  46 . In this example, a slider including the plurality of balls  44  and the slide rails are used as the slide mechanism  40 , but it is possible to use various known slide mechanisms  40  such as a ball spline and a linear bushing, for example. With the configuration described above, in the present embodiment, the plurality of placement section modules  20  are each supported by the frame member  6  via the slide mechanisms  40  in such a manner as to be slidable independently of each other. That is, the plurality of placement section modules  20  are slidable in the depth direction X relative to the frame member  6  independently of each other. 
     As shown in  FIGS.  3 ,  4 , and  7   , the slide mechanisms  40  support the corresponding placement section module  20  in such a manner that the placement section module  20  is slidable relative to the frame member  6  between a reference position T1 and a protruding position T2 that is on the back face side X2 in the depth direction relative to the reference position T1. When the placement section module  20  is at the reference position T1, the placement sections  10  are on the front face side X1 in the depth direction relative to a frame member back surface  22  that is a surface of the frame member  6  on the back face side X2 in the depth direction. When the placement section module  20  is at the protruding position T2, the placement sections  10  protrude from the frame member back surface  22  toward the back face side X2 in the depth direction. With this configuration, the placement section module  20  is movable between the reference position T1 and the protruding position T2. In the present embodiment, the plurality of placement sections  10 , the support member  18 , and the cover member  13 , which will be described later, slide together as the placement section module  20  between the reference position T1 and the protruding position T2. 
     As shown in  FIGS.  7  and  8   , the cover member  13  constituting a portion of the cover  3  covers a face  23  of the placement section module  20  on the back face side X2 in the depth direction. In the present embodiment, the faces  23  of the respective placement section modules  20  on the back face side X2 in the depth direction are covered with the cover members  13  constituting a portion of the cover  3 . Each placement section module  20  is provided with a single cover member  13 . The single cover member  13  covers the entirety of the face  23  of the placement section module  20  on the back face side X2 in the depth direction. In this example, the cover member  13  is a plate-shaped member. The cover member  13  is attached to the support member  18  of the placement section module  20 . More specifically, the cover member  13  is fixed to a surface of the support member  18 , which surface faces the back face side X2 in the depth direction. The cover member  13  covers the plurality of placement sections  10  arranged side by side in the width direction Y, the storage regions S formed on the respective placement sections  10  (i.e., articles W placed on the placement sections  10 ), and the slide mechanisms  40  as viewed in the depth direction. Also, the cover member  13  is formed in such a manner that when two placement section modules  20  adjacent to each other in the up-down direction Z are both at the reference position T1, the cover members  13  adjacent to each other in the up-down direction Z are in contact with each other with no gap formed therebetween. In the illustrated example, the cover member  13  has a rectangular shape elongated in the width direction Y. The dimension of the cover member  13  in the up-down direction Z is set larger than the length from a lower end of the placement section  10  to an upper end of an article W in a state where the article W is placed on the placement section  10 . Also, the dimension of the cover member  13  in the width direction Y is set larger than the dimension of the single placement section module  20  in the width direction Y. In the illustrated example, the plurality of placement section module groups  20 T are arranged side by side in the width direction Y. The cover member  13  is formed in such a manner that when two placement section modules  20  adjacent to each other in the width direction Y are both at the reference position T1, the cover members  13  adjacent to each other in the width direction Y are in contact with each other with no gap formed therebetween. 
     In this example, a handle portion  38  is attached to the cover member  13 . The handle portion  38  is gripped by a worker or the like to move the placement section module  20  from the reference position T1 to the protruding position T2. The handle portion  38  is fixed to a surface of the cover member  13 , which surface faces the back face side X2 in the depth direction. In the illustrated example, two handle portions  38  are provided side by side in the width direction Y on each cover member  13 . 
     As shown in  FIGS.  3  and  8   , the placement section module  20  is configured in such a manner that the upper side of the storage regions S is exposed when the placement section module  20  is at the protruding position T2. In the present embodiment, the cover member  13  covering the placement section module  20  covers the back face side X2 of the placement section module  20  in the depth direction, but an upper face of the placement section module  20  is not provided with a member that covers the placement section module  20  like the cover member  13 . Accordingly, each of the plurality of placement section modules  20  is configured in such a manner that the upper side of the storage regions S is exposed in a state where the placement section module  20  is at the protruding position T2 and another placement section module  20  adjacent to the upper side of the placement section module  20  is at the reference position T1. Therefore, a worker or the like can slide one of the plurality of placement section modules  20  arranged in the up-down direction Z to the protruding position T2 and easily take out an article W from the upper side of the placement section module  20 . 
     5. Lock Mechanism 
     As shown in  FIGS.  3 ,  4 , and  5   , in the present embodiment, the automated warehouse  1  includes a lock mechanism  9  that restricts sliding movement of the plurality of placement section modules  20  realized by the slide mechanisms  40 . The lock mechanism  9  is switchable between a locked state in which sliding movement of all the placement section modules  20  is restricted and an unlocked state in which sliding movement of all the placement section modules  20  is allowed. In the present embodiment, the lock mechanism  9  enters the locked state to restrict sliding movement of all the placement section modules  20  in the depth direction X when power is supplied to the transport apparatus  4 , i.e., when articles W can be transferred by the transport apparatus  4 . On the other hand, when power is not supplied to the transport apparatus  4 , the lock mechanism  9  enters the unlocked state to allow sliding movement of all the placement section modules  20  in the depth direction X. Here, when articles W can be transferred by the transport apparatus  4 , there is no need to take out articles W from the back face  2 B side of the storage rack  2 . Accordingly, the lock mechanism  9  enters the locked state in a state where all the placement section modules  20  are at the reference position T1, and sliding movement of all the placement section modules  20  in the depth direction X is restricted. On the other hand, when power is not supplied to the transport apparatus  4 , articles W cannot be taken out by the transport apparatus  4 , and accordingly, it is necessary to allow a worker or the like to take out necessary articles W. Therefore, the lock mechanism  9  enters the unlocked state to allow all the placement section modules  20  to move between the reference position T1 and the protruding position T2. 
     As shown in  FIGS.  3  and  4   , the lock mechanism  9  includes a plurality of engagement protrusions  54  and a plurality of engagement portions  53  corresponding to the respective engagement protrusions  54 . Each placement section module  20  is provided with an engagement protrusion  54  and an engagement portion  53 . Specifically, the engagement protrusion  54  is attached to the cover member  13 , and the engagement portion  53  is attached to the back-face-side support  15 . The engagement protrusion  54  and the engagement portion  53  are disposed at corresponding positions in the up-down direction Z and the width direction Y. The engagement protrusion  54  and the engagement portion  53  engage with each other as a result of the placement section module  20  sliding to the reference position T1 from the back face side X2 in the depth direction relative to the reference position T1. In the state where the engagement protrusion  54  and the engagement portion  53  engage with each other, the engagement protrusion  54  is retained in the engagement portion  53  and kept from coming off the engagement portion  53  owing to a function of an electromagnetic lock  55  (see  FIG.  9   ) provided inside the engagement portion  53 . Thus, the lock mechanism  9  enters the locked state. On the other hand, in this example, power is not supplied to the electromagnetic lock  55  while power is not supplied to the transport apparatus  4 . Accordingly, in the unlocked state, the engagement protrusion  54  easily comes off the engagement portion  53  and slides in the depth direction X together with the placement section module  20 . Thus, the placement section module  20  is allowed to slide in the depth direction X in the unlocked state. Also, in this example, the storage rack  2  includes an operation portion  58  (see  FIG.  9   ). A worker can operate the operation portion  58  to switch the lock mechanism  9  between the locked state and the unlocked state. In this example, the operation portion  58  is an operation switch provided on the storage rack  2 . Note that there is no limitation to this configuration, and the operation portion  58  may be an operation switch provided on an operation panel of a control device  8  or the like, or a software switch operable with use of a terminal constituting the control device  8 . 
     6. Reference Position Detection Device 
     As shown in  FIGS.  2 ,  3 , and  5   , in the present embodiment, the automated warehouse  1  further includes a reference position detection device  7  configured to detect the presence of the placement section module  20  at the reference position T1. In this example, a plurality of reference position detection devices  7  are provided in correspondence with the respective placement section modules  20 . In the illustrated example, the engagement protrusion  54  and the engagement portion  53  function as the reference position detection device  7 . That is, when the engagement protrusion  54  engages with the engagement portion  53 , a sensor  61  (see  FIG.  9   ) provided inside the engagement portion  53  detects the engagement protrusion  54 . Thus, the reference position detection device  7  can detect the presence of the placement section module  20  at the reference position T1. As described above, in the present embodiment, the reference position detection device  7  is composed of the engagement protrusion  54 , the engagement portion  53 , and the sensor  61 . 
     7. Control Device 
     In order to realize the configuration described above, the automated warehouse  1  in the present embodiment further includes the control device  8  that controls the transport apparatus  4  as shown in  FIG.  9   . In this example, the control device  8  controls all electromagnetic locks  55  to cause the lock mechanism  9  to enter the locked state in the state where power is supplied to the transport apparatus  4 , i.e., articles W can be transferred by the transport apparatus  4 . This avoids a situation in which a worker slides the placement section modules  20  by mistake while the transport apparatus  4  is operating. When power supply to the transport apparatus  4  is interrupted due to a power failure or the like, for example, power supply to the electromagnetic locks  55  is interrupted as well, and accordingly, the lock mechanism  9  automatically switches from the locked state to the unlocked state. Therefore, the worker can move the placement section modules  20  from the reference position T1 to the protruding position T2 and take out articles W from the back face side of the storage rack  2 . In this example, the control device  8  also controls the electromagnetic locks  55  to switch the lock mechanism  9  between the locked state and the unlocked state in response to an operation made by the worker or the like on the operation portion  58 . In this case, the control device  8  can supply power only to the electromagnetic locks  55  or interrupt power supply to the electromagnetic locks  55  irrespective of whether or not power is supplied to the transport apparatus  4 . As described above, the control device  8  controls the electromagnetic locks  55  to switch the lock mechanism  9  between the locked state and the unlocked state. 
     In the present embodiment, the control device  8  prohibits the transport apparatus  4  from operating in a case where the presence of the placement section modules  20  at the reference position T1 cannot be detected by the reference position detection devices  7 . In this example, the control device  8  prohibits the transport apparatus  4  from operating, i.e., stops the transport apparatus  4  in a case where at least one placement section module  20  among the plurality of placement section modules  20  cannot be detected at the reference position T1 by the reference position detection devices  7 . In other words, the control device  8  prohibits the transport apparatus  4  from operating unless the presence of all the placement section modules  20  at the reference position T1 is detected by the reference position detection devices  7 . Accordingly, when power supply is restored after a power failure and the transport apparatus  4  is started again, for example, the transport apparatus  4  does not operate if at least one placement section module  20  among the plurality of placement section modules  20  is not at the reference position T1. Also, when the worker operates the operation portion  58  to switch the lock mechanism  9  from the unlocked state to the locked state as well, the transport apparatus  4  does not operate if at least one placement section module  20  among the plurality of placement section modules  20  is not at the reference position T1. 
     8. Other Embodiments 
     Next, other embodiments of the automated warehouse will be described. 
     (1) In the above embodiment, a configuration is described as an example in which each placement section module  20  includes a plurality of placement sections  10  adjacent to each other in the width direction Y. However, there is no limitation to this configuration, and a configuration is also possible in which each placement section module  20  includes only one placement section  10 . Alternatively, a configuration is also possible in which some placement section modules  20  among the plurality of placement section modules  20  each include only one placement section  10 , and the remaining placement section modules  20  each include a plurality of placement sections  10 . 
     (2) In the above embodiment, a configuration is described as an example in which the automated warehouse  1  includes a plurality of placement section modules  20  arranged next to each other in the up-down direction Z and the width direction Y. However, there is no limitation to this configuration, and a configuration is also possible in which the automated warehouse  1  includes only one placement section module  20 . Alternatively, a configuration is also possible in which the placement section modules  20  are arranged in a plurality of rows in the up-down direction Z and in a single column in the width direction Y. Alternatively, a configuration is also possible in which the placement section modules  20  are only arranged in a plurality of columns in the width direction Y. 
     (3) In the above embodiment, a configuration is described as an example in which the control device  8  prohibits the transport apparatus  4  from operating in a case where some placement section modules  20  among the plurality of placement section modules  20  are not at the reference position T1. However, there is no limitation to this configuration, and a configuration is also possible in which the control device  8  does not prohibit the transport apparatus  4  from operating even in the case where some placement section modules  20  among the plurality of placement section modules  20  are not at the reference position T1. In such a case, the control device  8  preferably controls the transport apparatus  4  in such a manner as to only prohibit the transport apparatus  4  from transferring articles W to the placement section modules  20  that are not at the reference position T1 and allow the transport apparatus  4  to transfer articles W to the other placement section modules  20  that are at the reference position T1. 
     (4) In the above embodiment, a configuration is described as an example in which the automated warehouse  1  includes the lock mechanism  9  that is switchable between the locked state in which sliding movement of all the placement section modules  20  is restricted and the unlocked state in which sliding movement of all the placement section modules  20  is allowed. However, there is no limitation to this configuration, and a configuration is also possible in which the automated warehouse  1  includes a plurality of lock mechanisms  9  and each lock mechanism  9  is configured to switch some placement section modules  20  between the locked state and the unlocked state. Alternatively, a configuration is also possible in which the automated warehouse  1  does not include the lock mechanism  9 . 
     (5) The configurations disclosed in each embodiment described above (including the above embodiment and the other embodiments, the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments so long as no contradiction arises. The embodiments disclosed in the present specification including the other configurations are examples in all aspects, and can be modified as appropriate within a range not departing from the gist of the present disclosure. 
     9. Outline of the Above Embodiment 
     The following describes an outline of the automated warehouse described above. 
     An automated warehouse includes: a storage rack configured to store a plurality of articles; and a transport apparatus configured to travel along a front face of the storage rack and transport the articles, wherein the storage rack includes: a plurality of placement sections on which the articles are placeable; a frame member supporting the plurality of placement sections; and a cover, the cover covers a back face of the storage rack, the plurality of placement sections are next to each other in both an up-down direction and a width direction orthogonal to the up-down direction as viewed in a depth direction that is a direction from the front face toward the back face or from the back face toward the front face, and storage regions in which the articles are storable are respectively formed between pairs of two placement sections adjacent to each other in the up-down direction, the automated warehouse further includes at least one placement section module including at least one placement section, the at least one placement section including one of the placement sections or a plurality of the placement sections adjacent to each other in the width direction, the at least one placement section module is supported by the frame member via a slide mechanism, the slide mechanism supports the at least one placement section module in such a manner that the at least one placement section module is slidable relative to the frame member between a reference position and a protruding position that is on a back face side in the depth direction relative to the reference position, the back face side in the depth direction being the back face side as seen from the front face side in the depth direction, when the at least one placement section module is at the reference position, the at least one placement section is on a front face side in the depth direction relative to a frame member back surface that is a surface of the frame member on the back face side in the depth direction, the front face side in the depth direction being the front face side as seen from the back face side in the depth direction, when the at least one placement section module is at the protruding position, the at least one placement section protrudes from the frame member back surface toward the back face side in the depth direction, the cover includes a cover member covering a face of the at least one placement section module on the back face side in the depth direction, and the at least one placement section module is configured in such a manner that an upper side of the storage regions is exposed in a state where the at least one placement section module is at the protruding position. 
     According to this configuration, when the placement section module is slid to the protruding position, articles can be easily taken out from the upper side of the placement section module. Also, when the placement section module is at the reference position, the back face of the storage rack can be covered with the cover including the cover member. 
     As described above, the automated warehouse is configured to take out articles from the upper side of the placement section module in the state where the placement section module has been slid to the protruding position, and therefore, a worker can easily take out articles when compared with a case where the cover covering the back face of the plurality of placement sections is merely removed to take out articles in the depth direction. Moreover, there is no need to make the distance between the plurality of placement sections in the up-down direction large in order to make it easy for the worker to take out articles as in the case where articles are taken out in the depth direction, and therefore, it is easy to increase the efficiency of storing articles in the storage rack. 
     Here, it is preferable that the at least one placement section module includes a plurality of placement section modules arranged next to each other in the up-down direction, each of the plurality of placement section modules is supported by the frame member via the slide mechanism in such a manner that the placement section modules are slidable independently of each other, and each of the plurality of placement section modules is configured in such a manner that the upper side of the storage regions is exposed in a state where the placement section module is at the protruding position and another placement section module adjacent to an upper side of the placement section module is at the reference position. 
     According to this configuration, when one of the plurality of placement section modules arranged in the up-down direction is slid to the protruding position, articles can be easily taken out from the upper side of the placement section module. When the plurality of placement section modules are arranged in the up-down direction as described above, articles can be easily taken out from each of the placement section modules. Also, the efficiency of storing articles in the storage rack can be further increased because the distance between placement sections in the up-down direction of each placement section module need not be made large as in the case where articles are taken out in the depth direction. 
     It is preferable that the automated warehouse further includes a reference position detection device configured to detect presence of the at least one placement section module at the reference position; and a control device configured to control the transport apparatus, wherein the control device prohibits the transport apparatus from operating in response to the presence of the at least one placement section module at the reference position not being detected by the reference position detection device. 
     If the transport apparatus attempts to transfer an article to a placement section included in the placement section module in a state where the placement section module is not at the reference position, not only the article cannot be transferred properly but also the article may be damaged. According to this configuration, the transport apparatus does not operate when the presence of the placement section module at the reference position cannot be detected by the reference position detection device. Therefore, such situations can be avoided. 
     It is preferable that the at least one placement section module includes a plurality of placement section modules, the automated warehouse further includes a lock mechanism configured to restrict sliding movement of the plurality of placement section modules realized by the slide mechanism, and the lock mechanism is switchable between a locked state in which sliding movement of all the placement section modules is restricted and an unlocked state in which sliding movement of all the placement section modules is allowed. 
     According to this configuration, it is possible to avoid a situation in which a worker slides the placement section modules by mistake, by switching the lock mechanism to the locked state at normal time when there is no need to take out articles from the back face side of the storage rack. 
     INDUSTRIAL APPLICABILITY 
     The techniques according to the present disclosure are applicable to automated warehouses.