PATENT ABSTRACT
A coupling member is coupled to a support column of a rack. A plate-shaped member is rotatably engaged with a coupling member with one longitudinal end as an axis. An L-shaped member includes a first flat plate and a second flat plate orthogonal to the first flat plate and includes, with a transverse end of the first flat plate rotatably engaged with one plate face of the plate-shaped member with the longitudinal direction of the plate-shaped member as an axis and with a plate face of the first flat plate in intimate contact with the one plate face, a mounting member in which the second flat plate protrudes from one transverse end of the plate-shaped member and a fixing mechanism that fixes the mounting member with the plate face of the first flat plate in intimate contact with the one plate face of the plate-shaped member.

PATENT DESCRIPTION
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/JP2011/069083, filed on Aug. 24, 2011, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The embodiments discussed herein are related to a casing mounting rail, a blank plate, and a rack mount system. 
       BACKGROUND 
       [0003]    In a computer system, as the scale of the system increases, the number of electronic devices in the system such as servers, storages, and network devices increases. For the increased number of electronic devices, a storage frame called a rack is used to store the electronic devices efficiently and achieve space saving. To mount the electronic devices in the rack, casing mounting rails for mounting the casing of the electronic devices are laid from the front side to the rear side of the rack. The electronic devices are mounted in the rack in a stacked manner with their casing mounted on the casing mounting rails. 
         [0004]    This casing mounting rail is fixed to a support on the front side of the rack and another support on the rear side of the rack. Processes for fixing the casing mounting rail to the rack thus include a fixation process on the front side of the rack and a fixation process on the rear side of the rack. 
         [0005]    When mounted to a rack, the electronic devices do not necessarily fill the rack. When the electronic devices thus mounted do not fill the rack, a part with no electronic device mounted results in space within the rack. In this case, when such space is given on the front face of the rack, the exhaust air of the electronic devices is returned and sucked back into the electronic devices. This state interferes with appropriate cooling of the electronic devices and accumulates heat in the electronic devices, which causes a failure. In view of these circumstances, a blank plate is attached to fill the space on the front face in racks. 
         [0006]    As such a filling blank plate in related art, a blank plate serves as a shelf to house a printed circuit board on which electronic circuits are mounted. When the printed circuit board is inserted, the blank plate opens and serves as a guide rail supporting the insertion of the printed circuit board (Japanese Laid-open Patent Publication No. 11-340655). 
         [0007]    A conventional general blank plate is a monolithic plate formed of iron or the like, and is selectively attached according to the size of open space as occasion demands. Because of this, to mount a new electronic device to the open space, space used to mount the electronic device is checked in advance, a mounting place is determined, and a blank plate attached to the place is removed. Subsequently, casing mounting rails for mounting the electronic device are laid, and the electronic device is mounted on the casing mounting rails. The process for mounting the electronic device to the open space of the rack is thus complicated and time consuming. 
         [0008]    The conventional technology that functions as both the guide rail and the blank plate reduces the trouble with removing a blank plate and the trouble with laying rails. However, in an electronic device such as a server, its casing has a thickness. Given this situation, in this conventional technology, when a plurality of blank plates are arranged, an electronic device comes into contact with a protrusion for mounting the electronic device, making it hard to mount the electronic device. 
       SUMMARY 
       [0009]    According to an aspect of an embodiment, a casing mounting rail includes: a coupling member coupled to a support column of a rack; a plate-shaped member rotatably engaged with the coupling member with one longitudinal end as an axis; a mounting member including a first flat plate and a second flat plate orthogonal to the first flat plate, with a transverse end of the first flat plate rotatably engaged with one plate face of the plate-shaped member with a longitudinal direction of the plate-shaped member as an axis and with a plate face of the first flat plate in intimate contact with the one plate face, the second flat plate protruding from one transverse end of the plate-shaped member; and a fixing mechanism that fixes the mounting member with the plate face of the first flat plate in intimate contact with the one plate face. 
         [0010]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0011]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is a perspective view illustrating casing mounting rails according to a first embodiment when installed in a rack; 
           [0013]      FIG. 2  is a drawing illustrating the rotation of the casing mounting rails according to the first embodiment with respect to a support; 
           [0014]      FIG. 3A  is a perspective view illustrating the casing mounting rail according to the first embodiment when installed in the rack, viewed in the direction of the arrow P; 
           [0015]      FIG. 3B  is a perspective view illustrating the casing mounting rail according to the first embodiment when installed in the rack, viewed in the direction of the arrow Q; 
           [0016]      FIG. 4A  is a drawing illustrating the casing mounting rails according to the first embodiment viewed in the direction of the arrow P; 
           [0017]      FIG. 4B  is a drawing illustrating the casing mounting rails according to the first embodiment viewed in the direction of the arrow Q; 
           [0018]      FIG. 5  is an exploded view illustrating the casing mounting rail according to the first embodiment; 
           [0019]      FIG. 6  is a drawing illustrating the casing mounting rail according to the first embodiment viewed in the direction of the arrow Q; 
           [0020]      FIG. 7  is an enlarged view illustrating the area A in  FIG. 6 ; 
           [0021]      FIG. 8  is the B-B sectional view of  FIG. 6 ; 
           [0022]      FIG. 9  is a sectional view illustrating an engaging shaft; 
           [0023]      FIG. 10  is a sectional view illustrating an engaging hole of engaging parts  111 A to  111 C for passing the engaging shaft through; 
           [0024]      FIG. 11A  is a drawing illustrating a state in which the engaging shaft is lifted; 
           [0025]      FIG. 11B  is a drawing illustrating a state in which the engaging shaft is fit in a bearing; 
           [0026]      FIG. 12  is a plan view illustrating an L-shaped member in a movable state; 
           [0027]      FIG. 13  is a plan view illustrating the L-shaped member in a fixed state; 
           [0028]      FIG. 14  is a drawing illustrating a state in which a casing is mounted; 
           [0029]      FIG. 15A  is a perspective view illustrating a state in which the casing mounting rail is rotating; 
           [0030]      FIG. 15B  is a perspective view illustrating a state in which the rotation of the casing mounting rail is completed; 
           [0031]      FIG. 16  is an enlarged view illustrating a fitting part between the casing mounting rail and the rack; 
           [0032]      FIG. 17A  is a perspective view illustrating a state in which a casing is mounted; 
           [0033]      FIG. 17B  is a drawing illustrating a state of the casing mounting rails when the casing is mounted; 
           [0034]      FIG. 18A  is a perspective view illustrating a state in which a shallow casing is mounted; 
           [0035]      FIG. 18B  is a drawing illustrating a state of casing mounting rails when the shallow casing is mounted; 
           [0036]      FIG. 19A  is a perspective view illustrating a state in which a deep casing is mounted; and 
           [0037]      FIG. 19B  is a drawing illustrating a state of casing mounting rails when the deep casing is mounted. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0038]    Preferred embodiments of the present invention will be explained with reference to accompanying drawings. 
         [0039]    The following embodiments do not limit the casing mounting rail, the blank plate, and the rack mount system disclosed by the present application. Because the blank plate serves also as the casing mounting rail, the blank plate will be described as the casing mounting rail. 
       [a] First Embodiment 
       [0040]      FIG. 1  is a perspective view illustrating casing mounting rails according to a first embodiment when installed in a rack. 
         [0041]    Supports  2 A to  2 F are supports of the rack according to the present embodiment. The supports  2 A to  2 F extend in the vertical direction with respect to the ground with the rack installed. In the following, the ground side face of the rack when the rack is installed, which is the lower face in  FIG. 1 , is referred to as “the bottom face of the rack.” The face of the rack opposite the ground, which is the upper face in  FIG. 1 , is referred to as “the upper face of the rack.” In the following description, a direction directing from the support  2 B toward the support  2 A is referred to as the “left,” and a direction directing from the support  2 A toward the support  2 B is referred to as the “right.” 
         [0042]    The support  2 A and the support  2 B form a front face of the rack, that is, an outer face of the rack on a side through which an electronic device such as a server is put in and out. In the following, a plane formed by the support  2 A and the support  2 B is referred to as “the front face of the rack.” The support  2 E and the support  2 F form a back face of the rack, that is, an outer face of the rack facing the face through which an electronic device such as a server is put in and out. In the following, a surface formed by the support  2 E and the support  2 F is referred to as “the back face of the rack.” The support  2 C is provided in between the support  2 A and the support  2 E. The support  2 D is provided in between the support  2 B and the support  2 F. The distance between the support  2 A and the support  2 C and the distance between the support  2 B and the support  2 D have the same length as the longitudinal length of a casing mounting rail  1 L and a casing mounting rail  1 R, respectively, as will be described below. 
         [0043]    The casing mounting rail  1 L and casing mounting rails  11 L to  15 L are attached to the support  2 A. The casing mounting rail  1 R and casing mounting rails  11 R to  15 R are attached to the support  2 B. The casing mounting rails  1 L and  11 L to  15 L have the same structure. The casing mounting rails  1 R and  11 R to  15 R have the same structure. The casing mounting rails  1 L and  1 R,  11 L and  11 R,  12 L and  12 R,  13 L and  13 R,  14 L and  14 R, and  15 L and  15 R each form a pair. When a pair of casing mounting rails is described in the following, the casing mounting rail  1 L and the casing mounting rail  1 R will be described as an example. Each pair of casing mounting rails has nearly a bilateral symmetric structure. In view of this, when the structure of a casing mounting rail is described, the casing mounting rail  1 L will be described as an example. In other words, the casing mounting rails  11 L to  15 L have the same structure as that of the casing mounting rail  1 L described below. The casing mounting rails  1 R and  11 R to  15 R have nearly the same structure as a bilateral symmetric structure of the casing mounting rail  1 L. 
         [0044]    As illustrated in  FIG. 1 , a direction indicated by the arrow P directing from the front face of the rack to the back face of the rack is referred to as the P direction, and in contrast, a direction indicated by the arrow Q directing from the back face of the rack to the front face of the rack is referred to as the Q direction. 
         [0045]    The following describes the rotational motion of the casing mounting rails with respect to the supports of the rack with reference to  FIG. 2 .  FIG. 2  is a drawing illustrating the rotation of the casing mounting rails according to the first embodiment with respect to the supports. 
         [0046]    As will be described below, the casing mounting rails  1 L and  11 L to  15 L are attached to the support  2 A rotatably in a plane having the longitudinal direction of the support  2 A as a normal line. Similarly, the casing mounting rails  1 R and  11 R to  15 R are attached to the support  2 B rotatably in a plane having the longitudinal direction of the support  2 A as a normal line.  FIG. 2  illustrates a shift in the stationary positions of the casing mounting rails during rotation starting from the positions of the casing mounting rails  15 L and  15 R in parallel to the front face of the rack to the positions of the casing mounting rails  1 L and  1 R in parallel to the side faces of the rack. The casing mounting rails play a role of blank plates in the state of the casing mounting rails  15 L and  15 R. The casing mounting rails can mount the casing of an electronic device in the state of the casing mounting rails  1 L and  1 R. 
         [0047]      FIG. 3A  is a perspective view illustrating the casing mounting rail according to the first embodiment when installed in the rack viewed in the direction of the arrow P.  FIG. 3B  is a perspective view illustrating the casing mounting rail according to the first embodiment when installed in the rack viewed in the direction of the arrow Q.  FIG. 4A  is a drawing illustrating the casing mounting rails according to the first embodiment viewed in the direction of the arrow P.  FIG. 4B  is a drawing illustrating the casing mounting rails according to the first embodiment viewed in the direction of the arrow Q. 
         [0048]    In  FIG. 3A , to make the state of the casing mounting rail easy to understand, the casing mounting rail  1 L and the casing mounting rail  1 R in  FIG. 1  are illustrated in an enlarged manner. In  FIG. 3B , for understanding of the state of the casing mounting rail when viewed from the Q direction, the casing mounting rail  1 L and the casing mounting rail  1 R in  FIG. 1  are illustrated in an enlarged manner. In  FIG. 4A , although the casing mounting rail  1 L and the casing mounting rail  1 R are actually hidden behind the supports  2 A and  2 B, the supports are illustrated in a perspective manner for the convenience of description. 
         [0049]    The casing mounting rail  1 L and the casing mounting rail  1 R have the same length. As illustrated in  FIG. 3A ,  FIG. 3B ,  FIG. 4A , and  FIG. 4B , when the casing mounting rails  1 L and  1 R are positioned on the plane formed by the support  2 A and the support  2 B, the sum of the longitudinal lengths of the casing mounting rails  1 L and  1 R corresponds to the distance between the support  2 A and the support  2 B. In other words, the length of the casing mounting rails  1 L and  1 R corresponds to half the distance between the support  2 A and the support  2 B. 
         [0050]    As illustrated in  FIG. 4A , the casing mounting rail  1 L is fixed to the support  2 A with screws  3 A and  3 B. The casing mounting rail  1 R is fixed to the support  2 B with screws  3 C and  3 D. The fixation between the casing mounting rail  1 L and the support  2 A will be described below in detail. 
         [0051]    In the following description, a side of the casing mounting rail  1 L illustrated in  FIG. 4A , that is, a side of the casing mounting rail  1 L viewed from the P direction in  FIG. 3A  is referred to as the “front side.” A side of the casing mounting rail  1 L illustrated in  FIG. 4B , that is, a side of the casing mounting rail  1 L viewed from the Q direction in  FIG. 3B  is referred to as the “back side.” 
         [0052]    The following describes the structure of the casing mounting rail  1 L in detail with reference to  FIG. 5 .  FIG. 5  is an exploded view of the casing mounting rail according to the first embodiment. 
         [0053]    As illustrated in  FIG. 5 , the casing mounting rail  1 L includes a plate-shaped member  101 , an L-shaped member  102 , an engaging shaft  103 , a coupling member  104 , leaf springs  105 A to  105 C, screws  106 A and  106 B, a coil spring  107 , and an engaging shaft  108 . 
         [0054]    The plate-shaped member  101  includes a plate member  110 , engaging parts  111 A to  111 C, engaging parts  114 A to  114 C, a rubber sheet  115 , a magnet  118 , a protrusion  117 , and screws  119 A and  119 B. 
         [0055]    A recess  113  is formed on the transverse end of the plate member  110  on the upper face side of the rack. A recess  112  is formed on the transverse end of the plate member  110  on the bottom face side of the rack. The engaging parts  114 A to  114 C are formed on the longitudinal end of the plate member  110  on the coupling member  104  side. The engaging parts  111 A to  111 C are formed on the back side of the plate member  110 . A bending part  116  bending in an L shape toward the back side is formed on the longitudinal end of the plate member  110  opposite the coupling member  104 . The protrusion  117  extends from the end of the bending part  116  opposite the plate member  110  in a direction departing from the coupling member  104 . 
         [0056]    The magnet  118  is arranged on the side of the bending part  116  opposite the coupling member  104 . The magnet  118  is fixed to the bending part  116  with the screws  119 A and  119 B. In the present embodiment, the magnet  118  and the screws  119 A and  119 B are not arranged on the counter casing mounting rail, such as the casing mounting rail  1 R corresponding to the casing mounting rail  1 L. In place of the magnet  118 , a metal attracted to a magnet is arranged on the counter casing mounting rail. This causes, for example, the casing mounting rail  1 L and the casing mounting rail  1 R to be attracted to each other to stay parallel to the front face of the rack through magnetic force. Consequently, the casing mounting rail according to the present embodiment does not open even when receiving wind or the like, serving as a blank plate satisfactorily. In the present embodiment, the magnet is arranged on one part and the metal attracted to the magnet is arranged on the other part, to which another configuration may be applied. For example, magnets having polarities that are attracted to each other may be arranged. Another locking mechanism such as a bolt may be provided, so long as the casing mounting rails in pairs can be fixed to each other. 
         [0057]    The rubber sheet  115 , which is plate-shaped and has a length corresponding to the longitudinal length of the recess  113 , is arranged on the recess  113  of the plate member  110 . This rubber sheet  115  becomes deformed to allow the rotational motion of the L-shaped member  102 , as will be described below. The rubber sheet  115  thus arranged leaves no gap on the front face of the rack even when the L-shaped member  102  is in a fixed state, thereby maintaining the effect of cooling electronic devices. 
         [0058]    The coupling member  104  includes an L-shaped plate member  140  and engaging parts  142 A and  142 B. 
         [0059]    The engaging parts  142 A and  142 B are arranged on one transverse end of the L-shaped plate member  140 . 
         [0060]    A hole  141  for fixation to the support  2 A is formed on the surface of the L-shaped plate member  140  opposite the surface having the engaging parts  142 A and  142 B, that is, on the surface parallel to the plate member  110  in  FIG. 5 . Although only one hole  141  is visible in  FIG. 5 , actually three holes are formed. The holes  141  and holes of the support  2 A are aligned to each other and are fixed with the screws  3 A and  3 B illustrated in  FIG. 4A , thereby fixing the L-shaped plate member  140  and the support  2 A to each other. In the following, the surface of the L-shaped plate member  140  parallel to the plate member  110  in  FIG. 5  will be referred to as the “coupling surface.” 
         [0061]    The plate-shaped member  101  and the coupling member  104  are engaged with each other so that the engaging part  142 A is interposed between the engaging parts  114 A and  114 B and the engaging part  142 B is interposed between the engaging parts  114 B and  114 C. The engaging part  142 B is formed with a groove nearly at its center, and the coil spring  107  is fit in the groove. The coil spring  107  is arranged so as to hold the plate member  110  and the L-shaped plate member  140  therein. The engaging shaft  108  is disposed so as to pass through the engaging parts  114 A to  114 C, the engaging parts  142 A and  142 B, and the coil spring  107 . This causes the plate-shaped member  101  and the coupling member  104  to pivotally move about the engaging shaft  108 . In other words, when the coupling member  104  is fixed to the support  2 A, the plate-shaped member  101  pivotally moves in a plane with the longitudinal direction of the support  2 A as a normal line. When the plate-shaped member  101  is parallel to the coupling surface of the coupling member  104  as in the state of  FIG. 5 , the longitudinal direction of the plate member  110  extends in a direction connecting between the support  2 A and the support  2 B (see  FIG. 1 ). When the plate-shaped member  101  in the state of  FIG. 5  rotates in a direction departing from the coupling surface of the coupling member  104 , the longitudinal direction of the plate member  110  moves from the direction connecting between the support  2 A and the support  2 B to a direction connecting between the support  2 A and the support  2 C (see  FIG. 1 ). When the plate-shaped member  101  moves in the direction departing from the coupling surface of the coupling member  104  from the state of  FIG. 5 , a force acts on the plate member  110  and the L-shaped plate member  140  through the coil spring  107  so as to make the plate member  110  and the L-shaped plate member  140  close to each other. In other words, a force acts on the plate member  110  so that its longitudinal direction is positioned on the plane formed by the support  2 A and the support  2 B (see  FIG. 1 ). This causes, when no casing is mounted, the plate-shaped member  101  to automatically move to the position of the front face of the rack. 
         [0062]    The L-shaped member  102  includes an L-shaped plate member  120  and engaging parts  121 A and  121 B. 
         [0063]    The L-shaped plate member  120  is a plate-shaped member having an L shape formed by a support plate  123  and a mounting plate  124 . The support plate  123  is a part of the L-shaped plate member  120  that is parallel to the plate member  110  in  FIG. 5 . The mounting plate  124  is a part of the L-shaped plate member  120  that is perpendicular to the plate member  110  in  FIG. 5 . 
         [0064]    The engaging parts  121 A and  121 B are arranged on a transverse end of the support plate  123 . Recesses  122 A to  122 C are formed on the transverse end of the support plate  123  so as to interpose the engaging parts  121 A and  121 B therebetween. 
         [0065]    The mounting plate  124  is formed in a trapezoidal shape of which the width in the normal line direction of the support plate  123  decreases from some midpoint in the longitudinal direction toward the ends. This is in order to facilitate mounting when an electronic device such as a server is mounted. The mounting plate  124  is not necessarily a trapezoid and may be a rectangle. 
         [0066]    The plate-shaped member  101  and the L-shaped member  102  are engaged with each other so that the engaging part  121 A is interposed between the engaging parts  111 A and  111 B and the engaging part  121 B is interposed between the engaging parts  111 B and  111 C. The engaging parts  111 A to  111 C have engaging holes. The engaging shaft  103  is disposed so as to pass through the engaging holes of the engaging parts  111 A to  111 C and the engaging parts  121 A and  121 B. This causes the plate-shaped member  101  and the L-shaped member  102  to pivotally move about the engaging shaft  103 . In other words, the L-shaped member  102  pivotally moves in a plane perpendicular to the longitudinal direction of the plate member  110 . The engaging shaft  103  is fixed to the engaging parts  121 A and  121 B with a screw  106 A that reaches the engaging hole through a through hole formed in the engaging part  121 A and a screw  106 B that reaches the engaging hole through a through hole formed in the engaging part  121 B. This causes the engaging shaft  103  to rotate together with the L-shaped member  102 . 
         [0067]    The recess  122 A is positioned at a place facing an opening  1101 A of the engaging part  111 A on the plate-shaped member  101 . The recess  122 B is positioned at a place facing an opening  1101 B of the engaging part  111 B on the plate-shaped member  101 . The recess  122 C is positioned at a place facing an opening  1101 C of the engaging part  111 C on the plate-shaped member  101 . 
         [0068]    The leaf springs  105 A to  105 C are arranged in the openings  1101 A to  1101 C, respectively. The leaf springs  105 A to  105 C are in contact with the engaging shaft  103  passing through the engaging parts  111 A to  111 C. The leaf springs  105 A to  105 C apply a force on the engaging shaft  103  in the transverse direction of the plate member  110  from the recess  112  toward the recess  113 . Described below in detail are the arrangement of the leaf springs  105 A to  105 C and their pressing against the engaging shaft  103 . 
         [0069]    The following describes the arrangement of the leaf springs  105 A to  105 C in detail with reference to  FIG. 6  to  FIG. 8 . The leaf spring  105 A or the leaf spring  105   c  is described here as an example, but the same description applies to all the leaf springs  105 A to  105 C. 
         [0070]      FIG. 6  is a drawing illustrating the casing mounting rail according to the first embodiment viewed in the direction of the arrow Q.  FIG. 7  is an enlarged view of the area A in  FIG. 6 .  FIG. 8  is the B-B sectional view of  FIG. 6 . 
         [0071]    Parts with numerals attached in  FIG. 6  are the same as the parts with the same numerals attached in  FIG. 5 . As illustrated in  FIG. 6 , the leaf springs  105 A to  105 C are arranged at the places of the openings  1101 A to  1101 C of the engaging parts  111 A to  111 C, respectively. 
         [0072]    More specifically, the leaf spring  105 B is arranged as illustrated in  FIG. 7 . Specifically, a base  153  is arranged on the recess  122 B side of the opening  1101 B of the engaging part  111 B. The leaf spring  105 B is placed on the base  153 . Fixing parts  151 A and  151 B are further arranged on the base  153  for fixing the leaf spring  105 B. The leaf spring  105 B presses the engaging shaft  103  toward the engaging shaft  103  from the base  153 . 
         [0073]    The following further describes the state of the leaf spring  105 C with reference to  FIG. 8 . As described above, the engaging part  111 C is formed on the plate member  110 . The opening  1101 C is formed in the engaging part  111 C at the place where the leaf spring  105 C is positioned. As illustrated in  FIG. 8 , the base  153  that extends perpendicularly from the plate member  110  is arranged on the recess  122 C side of the opening  1101 C. The fixing part  151 A is arranged on the base  153 . The leaf spring  105 C placed on the base  153  is fixed by the fixing part  151 A. The leaf spring  105 C presses the engaging shaft  103  toward the engaging shaft  103  from the base  153 . For example, in  FIG. 8 , when the L-shaped member  102  (see  FIG. 5 ) rotates about the engaging shaft  103 , the support plate  123  and the recess  122 C rotate, and the leaf spring  105 C, the base  153 , the engaging part  111 C, and the like do not rotate. 
         [0074]      FIG. 9  is a sectional view illustrating the engaging shaft  103 .  FIG. 10  is a sectional view illustrating a through hole of the engaging part  111 A for passing the engaging shaft through. 
         [0075]    As illustrated in  FIG. 9 , the sectional shape of the engaging shaft  103  includes arcs  131 A and  131 D and tapered parts  131 B and  131 C. The arcs  131 A and  131 D are on the circumference of the same circle. In other words, the engaging shaft  103  is obtained by trimming the sides of a rod-shaped member having the shape of the circumference of a circle including the arcs  131 A and  131 D as a section to form the tapered parts  131 B and  131 C. 
         [0076]    As illustrated in  FIG. 10 , the sectional shape of the through hole of the engaging part  111 A includes arcs  201  and  204  and tapered parts  202  and  203 . The tapered parts  202  and  203  and the arc  204  form a bearing for the engaging shaft  103 . In the following, the recessed structure formed by the tapered parts  202  and  203  and the arc  204  may be referred to as the “bearing.” The engaging part  111 A is described here as an example, whereas the engaging parts  111 B and  111 C also have the same through hole. In this through hole, a line connecting the center of the arc  201  and the center of the arc  204  aligns with the transverse direction of the plate member  110  (see  FIG. 5 ). The arc  201  is arranged on the recess  113  side of the plate member  110 , and the arc  204  is arranged on the recess  112  side of the plate member  110 . 
         [0077]    The arcs  201  and  204  and the arcs  131 A and  131 D are arcs as parts of the circumference of a circle having the same radius. The angles of the tapered parts  202  and  203  are equal to the angles of the tapered parts  131 B and  131 C, respectively. The angle of the tapered parts is an angle with respect to a center line with respect to which a section of the engaging shaft  103  in  FIG. 9  or a section of the through hole in  FIG. 10  is bilaterally symmetric. 
         [0078]      FIG. 11A  is a drawing illustrating a state in which the engaging shaft is lifted.  FIG. 11B  is a drawing illustrating a state in which the engaging shaft is fit in the bearing. Both  FIG. 11A  and  FIG. 11B  illustrate sections in which the engaging shaft  103  passes through the through hole of the engaging part  111 A illustrated in  FIG. 7 . The following describes the fixation of the engaging shaft  103  with reference to  FIG. 11A  and  FIG. 11B . In the description here, for the convenience of description, the direction from the center of the arc  201  toward the center of the arc  204  in  FIG. 11A  and  FIG. 11B  is referred to as the downward direction, and the direction from the center of the arc  204  toward the center of the arc  201  is referred to as the upward direction. The upward and downward directions align with the transverse direction of the plate member  110  in  FIG. 5 . 
         [0079]    The engaging shaft  103  is pushed up from below by the leaf springs  105 A to  105 C (see  FIG. 5 ). With no other force acting on the engaging shaft  103 , as illustrated in  FIG. 11A , the arc  131 A of the engaging shaft  103  is in contact with the upper arc  201  of the through hole of the engaging part  111 A. In this case, the engaging shaft  103  can rotate freely within the through hole. 
         [0080]    In contrast, when a force larger than the pressing forces of the leaf springs  105 A to  105 C (see  FIG. 5 ) acts on the engaging shaft  103  downward, the engaging shaft  103  is pressed against the bearing side. This causes the tapered part  131 B to be in contact with the tapered part  202 , the tapered part  131 C to be in contact with the tapered part  203 , and the arc  131 D to be in contact with the arc  204  as illustrated in  FIG. 11B . In this case, the rotational motion of the engaging shaft  103  is inhibited by the parts in contact therewith, fixing the engaging shaft  103  not to rotate within the engaging part  111 A. The above describes about the fixation of the engaging shaft  103  with the engaging part  111 A, and similarly for the engaging parts  111 B and  111 C, when the force acts downward, the engaging shaft  103  is fixed also by the engaging parts  111 B and  111 C. 
         [0081]    The following describes overall motion relating to the pivoting motion of the L-shaped member  102  with reference to  FIG. 12  and  FIG. 13 . 
         [0082]      FIG. 12  is a plan view illustrating the L-shaped member  102  in a movable state.  FIG. 13  is a plan view illustrating the L-shaped member  102  in a fixed state. The description is provided here with the downward direction in  FIG. 12  and  FIG. 13  referred to as the downward direction and the upward direction in  FIG. 12  and  FIG. 13  referred to as the upward direction. The downward direction in the drawings is a direction toward the bottom face of the rack, and the upward direction in the drawings is a direction toward the upper face of the rack. 
         [0083]    As described above, when no downward force acts on the leaf springs  105 A to  105 C, the leaf springs  105 A to  105 C press the engaging shaft  103  upward. This force is represented by a tension T in  FIG. 12 . As described above, when the tension T acts, the engaging shaft  103  is pressed upward in a state as illustrated in  FIG. 11A  and allowed to rotate freely within the through hole of the engaging part  111 A. In this case, the L-shaped member  102  rotates in a direction departing from the plate member  110  owing to the weight of the mounting plate  124 . As a result, as illustrated in  FIG. 12 , the support plate  123  departs from the plate member  110 , tilting the L-shaped member  102 . 
         [0084]    In this situation, the mounting plate  124  moves toward the lower plate member  110  side through the rotation. As described above, the recess  113  is formed on the upper side of the plate member  110 , and the rubber sheet  115  is arranged therein. As a result, the mounting plate  124  can move without interfering with the plate member  110  through the deformation of the rubber sheet  115 . This causes the mounting plate  124  to move from the inside of the rack toward the outside thereof, preventing it from being in contact with the casing of a server or the like. 
         [0085]    The following describes a case in which a downward force is acting on the leaf springs  105 A to  105 C (see  FIG. 5 ). The force acting on the leaf springs  105 A to  105 C (see  FIG. 5 ) is represented by a force S in  FIG. 13 . This force S is a force acting when the casing of a serve or the like is mounted. As described above, when the force S acts, the engaging shaft  103  moves downward to be fit into the bearing of the engaging part  111 A. This fixes the engaging shaft  103  not to rotate. Because the engaging shaft  103  and the L-shaped member  102  are fixed to each other, when it is difficult for the engaging shaft  103  to rotate, the L-shaped member  102  is also fixed and has difficulty in pivotally moving. 
         [0086]    In this case, the L-shaped member  102  is fixed in the state of  FIG. 13 . Specifically, the support plate  123  is in contact with the plate member  110 . The mounting plate  123  is positioned in a direction perpendicular to the plate member  110 , that is, in a direction parallel to the bottom face of the rack. In this situation, the mounting plate  124  passes through the recess  112  (see  FIG. 5 ) on the lower side of the plate member  110 . In other words, when the casing of a server or the like is mounted on the mounting plate  124 , the L-shaped member  102  is fixed as in the state of  FIG. 13  through the weight of the casing and supports the casing. 
         [0087]      FIG. 14  is a diagram illustrating a state in which a casing is mounted. In  FIG. 14 , the casing mounting rails  1 L,  11 L, and  12 L are in a position parallel to the side face of the rack, that is, the position of the casing mounting rail  1 L in  FIG. 2 . In  FIG. 14 , a server  300  illustrated by the two-dot chain line is mounted.  FIG. 14  illustrates a state in which the casing of the server  300  is mounted on the casing mounting rail  12 L among the casing mounting rails  1 L,  11 L, and  12 L attached to the support  2 A. 
         [0088]    Because the weight of the server is acting on the casing mounting rail  12 L, the mounting plate  124  of the casing mounting rail  12 L is fixed in a direction parallel to the bottom face of the rack. In this state, the server  300  is mounted on the mounting plate  124  of the casing mounting rail  12 L. 
         [0089]    In contrast, the weight of the server is not acting on the casing mounting rails  1 L and  11 L. As a result, the casing mounting rails  1 L and  11 L can pivotally move. This causes the casing mounting rails  1 L and  11 L to rotate in a direction toward the outside of the rack through the weights of the respective mounting plates  124 . As a result, as illustrated in  FIG. 14 , the mounting plates  124  of the casing mounting rails  1 L and  11 L retract to a position off a position being in contact with the server. This causes the server  300  to be smoothly stored in the rack without interfering with the mounting plates  124  of the casing mounting rails  1 L and  11 L. 
         [0090]    The following describes the support of the casing mounting rail  1 L by the support  2 C with reference to  FIG. 15A ,  FIG. 15B , and  FIG. 16 .  FIG. 15A  is a perspective view illustrating a state in which the casing mounting rail is rotating.  FIG. 15B  is a perspective view illustrating a state in which the rotation of the casing mounting rail is completed.  FIG. 16  is an enlarged view illustrating a fitting part between the casing mounting rail and the rack. 
         [0091]    When the casing mounting rail  1 L becomes parallel to the side face of the rack, in order to mount the casing of an electronic device, not only the side fixed to the support  2 A but also the opposite side are fixed. This fixation of the casing mounting rail  1 L is performed by the support  2 C. 
         [0092]    As illustrated in  FIG. 15A , the casing mounting rail  1 L has the protrusion  117 . A recess  210  is formed in the support  2 C at a position corresponding to the protrusion  117  when the casing mounting rail  1 L becomes parallel to the side face of the rack. As illustrated in  FIG. 15B  and  FIG. 16 , when the casing mounting rail  1 L becomes parallel to the side face of the rack, the protrusion  117  and the recess  210  are fit to each other. This causes the support  2 C to support the protrusion  117  through the recess  210  when a force acts on the casing mounting rail  1 L toward the bottom face of the rack when, for example, a casing is mounted, thereby supporting the casing mounting rail  1 L. 
         [0093]    The following describes a state in which the casing of a server is mounted with reference to  FIG. 17A  and  FIG. 17B .  FIG. 17A  is a perspective view illustrating a state in which a casing is mounted.  FIG. 17B  is a drawing illustrating a state of the casing mounting rails when the casing is mounted.  FIG. 17A  is a drawing illustrating a case when a server  301  is mounted on the rack in the state of  FIG. 1 .  FIG. 17B  illustrates a state when the server  301  is removed in  FIG. 17A . 
         [0094]    As illustrated in  FIG. 17A  and  FIG. 17B , when the 3 U server  301  is inserted, three pairs of casing mounting rails, that is, the casing mounting rails  1 L,  11 L,  12 L,  1 R,  11 R, and  12 R are pushed inside the rack. The casing mounting rails  1 L,  11 L, and  12 L are fit into the support  2 C. The casing mounting rails  1 R,  11 R, and  12 R are fit into the support  2 D. The casing mounting rails  12 L and  12 R are fixed through the weight of the server  301  and support the casing of the server  301  from the bottom face side of the rack. The casing mounting rails  13 L to  15 L and  13 R to  15 R maintain the function as blank plates even after the server  301  is mounted. 
         [0095]    When the server  301  is removed from the state of  FIG. 17A , the casing mounting rails  1 L,  11 L,  12 L,  1 R,  11 R, and  12 R rotate toward the front face of the rack through a force applied by the coil spring  107  and stop at the position parallel to the front face of the rack, thus returning to the state of  FIG. 1 . 
         [0096]    As described above, the casing mounting rail according to the present embodiment has a role of a blank plate when no electronic device is mounted. When the casing mounting rail according to the present embodiment mounts an electronic device, simply inserting the electronic device pushes in an appropriate number of the casing mounting rail, thereby exhibiting the function of mounting the casing. In addition, simply removing the mounted electronic device causes the casing mounting rail according to the present embodiment to automatically return to a position as the blank plate to play the role of the blank plate. This eliminates the need for operators to consider the size of blank plates to be removed when mounting an electronic device, eliminates a process of removing blank plates, and saves time and effort for fixing rails to supports. This allows operators to reduce time and effort in operation. In the fixation of rails, time and effort have been needed for alignment for fixing rails to the support on the front face of the rack and the support on the back face of the rack; such time and effort are also reduced. After removing the mounted electronic device, processes of selecting and installing blank plates according to space have been conventionally needed; such time and effort are also reduced using the casing mounting rail according to the present embodiment. 
       [b] Second Embodiment 
       [0097]    The following describes a rack and a casing mounting rail according to a second embodiment. The present embodiment differs from the first embodiment in that casing mounting rails are arranged in a rack so that a deep casing can be mounted. The casing mounting rail according to the present embodiment has the same configuration as that according to the first embodiment. 
         [0098]      FIG. 18A  is a perspective view illustrating a state in which a shallow casing is mounted.  FIG. 18B  is a drawing illustrating a state of casing mounting rails when the shallow casing is mounted.  FIG. 19A  is perspective view illustrating a state in which a deep casing is mounted.  FIG. 19B  is a drawing illustrating a state of casing mounting rails when the deep casing is mounted. 
         [0099]    In the present embodiment, as illustrated in  FIG. 18A  to  FIG. 19B , in addition to the casing mounting rails  1 L,  11 L to  15 L and  1 R,  11 R to  15 R, casing mounting rails  16 L to  21 L and  16 R to  21 R are arranged also in between the front face of the rack and the back face of the rack. 
         [0100]    To attach the casing mounting rails  16 L to  21 L and  16 R to  21 R, a support  2 G and a support  2 H are provided in between the support  2 C and the support  2 E and in between the support  2 D and the support  2 F, respectively in the rack. The distance between the support  2 G and the support  2 E and the distance between the support  2 H and the support  2 F correspond to the longitudinal distances of the casing mounting rails  16 L to  21 L and  16 R to  21 R, respectively. 
         [0101]    The casing mounting rails  16 L to  21 L and  16 R to  21 R are fit in the support  2 E and the support  2 F, respectively, when they become parallel to the side faces of the rack. 
         [0102]    When no electronic device is mounted, the casing mounting rails  16 L to  21 L and  16 R to  21 R are closed at a position of a plane formed by the support  2 G and the support  2 H. 
         [0103]    As illustrated in  FIG. 18A  and  FIG. 18B , when the shallow casing is mounted, the casing does not reach the casing mounting rails  16 L to  21 L and  16 R to  21 R. In other words, for the shallow casing, the casing mounting rails  1 L and  11 L to  15 L and  1 R and  11 R to  15 R can support the casing. As a result, the casing mounting rails  16 L to  21 L and  16 R to  21 R are closed at the position of the plane formed by the support  2 G and the support  2 H. 
         [0104]    As illustrated in  FIG. 19A  and  FIG. 19B , when the deep casing is mounted, the casing reaches the casing mounting rails  16 L to  21 L and  16 R to  21 R. In other words, for the deep casing, the casing mounting rails  1 L and  11 L to  15 L and  1 R and  11 R to  15 R alone cannot support the casing. As a result, part of the casing mounting rails  16 L to  21 L and  16 R to  21 R coming into contact with the casing are pushed in to play the role of the casing mounting rail. Because a server  302  is 3 U in  FIG. 19A  and  FIG. 19B , the casing mounting rails  16 L to  18 L and  16 R to  18 R are pushed in. The casing mounting rails  12 L,  12 R,  18 L, and  18 R play the role of the casing mounting rail. This supports the deep casing stably. 
         [0105]    With the back of the shallow casing obstructed by the casing mounting rails  16 L to  21 L and  16 R to  21 R, the exhaust air of the shallow casing is discharged to the side of rack, and the exhaust air of the deep casing is prevented from returning to the front by the casing mounting rails  16 L to  21 L and  16 R to  21 R. As a result, the cooling effect is maintained even for the shallow casing. 
         [0106]    As a modification, the casing mounting rails  16 L to  21 L and  16 R to  21 R may be reticulated, so long as their strength is ensured. Making them reticular causes the exhaust air of the shallow casing to reach the back face of the rack and makes the flow of the exhaust air similar to that of the first embodiment, thus achieving nearly the same cooling effect as the first embodiment. As another modification, the casing mounting rails  16 L to  21 L and  16 R to  21 R may be arranged at positions parallel to the sides of the rack at all times. In this case, the casing mounting rails  16 L to  21 L and  16 R to  21 R do not partition the rack in the middle, thus achieving nearly the same cooling effect as the first embodiment. 
         [0107]    As described above, the rack and the casing mounting rail according to the present embodiment holds even a deep casing. Even the deep casing can be mounted simply by pushing it, thus reducing working time for installing electronic devices. 
         [0108]    One aspect of the present invention reduces the trouble with mounting an electronic device to a rack. 
         [0109]    All examples and conditional language recited herein are intended for pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.