Abstract:
A component assembly includes a first component having a locking section and a flat-plate shaped projection formed on a first face. The locking section extends from the first face and bends in a first direction. The projection extends perpendicularly to the first face and is formed of a face intersecting the first direction. The assembly also includes a second component having a first hole and a second formed on a first face. The locking section of the first component is inserted into the first hole, and the projection of the first component is inserted into the second hole. The first face of the second component opposes the first face of the first component and includes a part with a slope section on which the distal end of the projection abuts and which moves the first component in the first direction when the first component is attached to the second component.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a component assembly in which plural components are assembled and an electronic apparatus a part of the housing of which is formed of the component assembly. 
         [0003]    2. Description of the Related Art 
         [0004]    There have been demands for electronic apparatus such as a personal computer and a cellular phone satisfying user friendliness and functionality, however, industrial design is also an important factor for selection for a user. Typically, electronic components are attached to a strong metallic housing frame to prevent the electronic components from being damaged by shock or the like. The housing frame is covered with a plastic cover to improve appearance. 
         [0005]    At the time of repair, however, the cover is removed from the housing frame and then the cover is attached again to the housing frame. At this point, if a screw is forcibly fastened into a wrong screw hole, the cover may be damaged, appearance may be marred or an interstice may be formed between the cover and the housing frame, through which moisture or dust enter to cause a failure. In order to avoid such an inconvenience, in general, the cover is first tentatively fixed to the housing frame and then the cover is fixed to the housing frame with a screw at the time of attaching the cover to the housing frame. As methods of tentatively fixing the cover to the housing frame, there have been generally utilized a technique (refer to WO99/10860) in which the battery cover of a cellular phone is detachably attached to the housing of a main body and a technique (refer to Japanese Patent Application Publication No. 05-59682) in which the cover of a recording cartridge such as a video tape is opened or closed to engage a prong or a protrusion provided on the cover with a locking hole or a recess provided on the housing frame. Three conventional methods of fixing a cover are described below. 
         [0006]      FIG. 1  is a schematic diagram describing a first method of fixing a cover to a housing frame. 
         [0007]    In the cover fixing method in  FIG. 1 , a protrusion  511   a  provided on a cover  511  is fitted into the recess of the housing frame  512  to tentatively fix the cover to the housing frame  512  and then the cover  511  is fastened with a screw  515  from the other side thereof. In addition, resin components  513  and  514  made of the same resin as the cover  511  are fixed to the housing frame  512  by integral molding. The resin components  513  and  514  and the cover  511  conceal electronic components and the housing frame  512 . The cover fixing method can easily attach the cover  511  to the housing frame  512  while avoiding an erroneous attachment, however, has a problem in that it takes cost and time to fix the resin components  513  and  514  to the housing frame  512  or to dismantle the resin components  513  and  514  at the time of a recycling work and the method is inflexible and thus cannot support variations of the cover  511 . 
         [0008]      FIG. 2  is a schematic diagram describing a second method of fixing a cover to a housing frame. 
         [0009]    A cover  521  is provided with a hook  521   a  and a pawl  521   b  and the housing frame  522  is provided with locking holes at positions corresponding to the hook  521   a  and the pawl  521   b  respectively. As illustrated in Part (A) of  FIG. 2 , the hook  521   a  and the pawl  521   b  of the cover  521  are engaged with the locking holes of the housing frame  522  respectively to tentatively fix the cover  521  to the housing frame  522 , thereafter, the cover  521  is fixed to the housing frame  522  with a screw. The cover fixing method illustrated in  FIG. 2  can tentatively fix the cover  521  to the housing frame  522  while suppressing a cost. However, as illustrated in Part (B) of  FIG. 2 , the method has a problem in that the pawl  521   b  may be broken when the cover is removed from the housing frame  522  and therefore the cover  521  cannot be repetitively attached and detached. 
         [0010]      FIG. 3  is a schematic diagram describing a third method of fixing a cover to a housing frame. 
         [0011]    A cover  531  illustrated in  FIG. 3  is provided with a hook  531   a  which is the same as the hook  521   a  in  FIG. 2 . A protrusion  531   b  is provided instead of the pawl  521   b  illustrated in  FIG. 2 . Furthermore, the cover  531  is provided with an auxiliary pawl  531   c  on a wall on the same side as the hook  531   a.  The use of the protrusion  531   b  makes engagement weaker than that of the pawl  521   b  illustrated in  FIG. 2 , thereby making it easier to remove the cover  521  from the housing frame  522 . Even if the engagement by the protrusion  531   b  is released, the auxiliary pawl  531   c  hooks the housing frame  532  to surely tentatively fix the cover  531 . As illustrated in Part (B) of  FIG. 3 , however, while the cover  531  is repetitively detached, the corners of the auxiliary pawl  531   c  are worn down to weaken the engagement of the auxiliary pawl  531   c.  As illustrated in Part (C) of  FIG. 3 , even when the hook  531   a  is not correctly engaged with the housing frame  532 , the cover  531  can be forcibly but incorrectly fixed to the housing frame  532  with a screw by the elastic deformation of the cover  531 . 
         [0012]    As described above, the conventional cover fixing methods have problems in that they are costly, removing the cover only several times damages the cover and the cover can be fixed to the housing frame with a screw with the cover not correctly attached. In recent years, electronic apparatus are available in which a user may select a cover with his/her preferred color or appearance from among several kinds of covers. In future, it is assumed that the replacement of a cover will be common. As is clear from the above, the development of a cover and a housing frame is demanded which are easily and repetitively detachable. 
       SUMMARY OF THE INVENTION 
       [0013]    The present invention has been made in view of the above circumstances and provides a component assembly and an electronic apparatus in which a cover can be repetitively attached to a housing frame or detached therefrom while suppressing increase in cost. 
         [0014]    A component assembly according to the present invention includes: 
         [0015]    a first component including a locking section and a flat-plate shaped projection which are formed on a first surface of the first component, the locking section extending from the first face and bending in a first direction, and the projection extending perpendicularly to the first face and formed of a face intersecting the first direction; and 
         [0016]    a second component including a first hole and a second hole which are formed on a first face of the second component, the first hole into which the locking section of the first component is inserted and locked, and the second hole into which the projection of the first component is inserted, the first face of the second component opposing the first face of the first component and including a part with a slope section on which a distal end of the projection of the first component abuts and which moves the first component in the first direction when the first component is attached to the second component. 
         [0017]    According to the basic feature of the component assembly, when a first component is attached to a second component, the distal end of a projection of the first component abuts on the slope section of the first component to move the first component in a first direction, and as a result, a locking section of the first component is locked by a first hole of the second component to attach the first component to the second component. Therefore, an excessive stress applied to the locking section and the projection when the first component is attached or detached to and from the second component can be reduced to prevent the locking section and the projection of the first component from being damaged or worn out. Furthermore, according to the basic feature of the component assembly of the present invention, the direction and the position of a pawl and a projection provided on a conventional housing frame or cover are merely changed to eliminate the need for preparing a new component, thereby suppressing increase in cost and enabling attachment and detachment of the first component to and from the second component repetitively. 
         [0018]    It is preferable, in addition to the basic feature of the component assembly, that the distal end of the projection of the first component has a slope section in such a shape that the slope section rubs on the slope section of the second component when the first component is attached to the second component. 
         [0019]    According to this additional feature of the component assembly, friction can be reduced between the slope section of the second component and the distal end of the projection of the first component to enable smooth attachment and detachment of the first component to and from the second component. 
         [0020]    It is also preferable, in addition to the basic feature of the component assembly, that the second hole is larger in size than the projection of the first component, and 
         [0021]    the part of the second component has a portion which regulates the movement of the projection against the entering of the projection of the first component from a predetermined direction. 
         [0022]    According to this preferable additional feature of the present invention, the projection of the first component can be easily inserted into the second hole of the second component, and if the projection is inserted from a wrong direction, the movement of the projection is regulated to prevent a wrong attachment. 
         [0023]    In the additional feature of the second hole being larger in size than the projection of the first component, it is preferable that the second component includes a second face which makes a predetermined angle with the first face of the second component and follows the first face, and 
         [0024]    the second hole extends to the first and the second faces of the second component. 
         [0025]    The second hole extending to the first and the second face is provided on the second component to allow the projection of the first component to be easily inserted thereinto. 
         [0026]    It is also preferable, in addition to the basic feature of the component assembly, that the first component includes a second face which makes a predetermined angle with the first face of the first component and follows the first face and a protrusion which protrudes toward the inside of the second face, and 
         [0027]    the second component includes a second face which makes the same angle as the predetermined angle of the first component and follows the first face and a recess which is formed on the second face of the second component and in which the protrusion formed on the second face of the first component is engaged when the first component is attached to the second component. 
         [0028]    According to this preferable additional feature of the present invention, when the first component is attached to the second component, the protrusion formed on the first component is fitted to the recess formed on the second component to surely fix the first component to the second component. 
         [0029]    In this additional feature of the first component having the protrusion and the second component having the recess, it is further preferable that the first component includes a screw insertion hole in the second face of the first component, and 
         [0030]    the second component includes a screw hole at a position in the second face of the second component corresponding to the screw insertion hole of the first component. 
         [0031]    If the first component is incorrectly attached to the second component, the second face of the first component is not parallel to the second face of the second component, so that the screw insertion hole of the first component and the screw hole of the second component are out of alignment. For this reason, according to the additional feature, the wrong attachment between the first and the second components can be prevented. 
         [0032]    The second faces of the first and the second components may correspond to the bottom face of an electronic apparatus and the like. Forming the screw insertion hole and the screw hole in the second faces of the first and the second components allows fixing the first component to the second component with screws on the bottom face which is inconspicuous. 
         [0033]    It is also preferable, in addition to the basic feature of the component assembly, that the first component further includes a second face which makes a predetermined angle with the first face of the first component and follows the first face, and the first component also includes, in addition to the projection, a supporting section which projects toward the inside of the second face to support the projection. 
         [0034]    The projection provided on the first component abuts the part provided on the first face of the second component when the first component is attached to the second component, so that the projection is supported by the supporting section from the second face side to increase the strength of the projection without interfering with the attachment and detachment of the first component. 
         [0035]    It is also preferable, in addition to the basic feature of the component assembly, that the second component includes a third hole, through which a third component appears, in the first face of the second component, and the first component includes a hole at a position in the first face of the first component corresponding to the third hole when the first component is attached to the second component. 
         [0036]    According to this additional feature, for example, the third component such as a switch is housed inside the first and the second components and the third component can be exposed to the outside through the holes formed in the first and the second components. 
         [0037]    It is also preferable, in addition to the basic feature of the component assembly, that the first component is made of resin, and 
         [0038]    the second component is made of metal. 
         [0039]    As for the component assembly formed of a resin component and a metal component is repetitively attached and detached, the resin component which is low in strength wears out more quickly. According to the basic feature of the component assembly, the wearing-out of the locking section and the projection of the first component is reduced, so that even if the first component is made of resin, the first component can be repetitively attached to the second component and detached therefrom. 
         [0040]    An electronic apparatus according to the invention includes: 
         [0041]    the component assembly, which has the above-described basic feature and any of the above-described additional features, as part of the housing of the electronic apparatus, 
         [0042]    wherein the second component is a housing frame, and 
         [0043]    the first component is a cover fixed to the housing frame. 
         [0044]    In electronic apparatus such as a personal computer, it is presumed that a cover is repetitively attached to or detached from the housing frame. According to the basic feature of the electronic apparatus, a cover can be repetitively attached to a housing frame or detached therefrom while suppressing increase in cost. 
         [0045]    As described above, according to the component assembly and the electronic apparatus of the present invention, a cover can be repetitively attached to a housing frame or detached therefrom while suppressing increase in cost. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0046]      FIG. 1  is a schematic diagram describing a first method of fixing a cover to a housing frame; 
           [0047]      FIG. 2  is a schematic diagram describing a second method of fixing a cover to a housing frame; 
           [0048]      FIG. 3  is a schematic diagram describing a third method of fixing a cover to a housing frame; 
           [0049]      FIG. 4  is an appearance of a personal computer being a concrete first embodiment of an electronic apparatus; 
           [0050]      FIG. 5  is a side elevation of the personal computer; 
           [0051]      FIG. 6  is a rear elevation of the personal computer; 
           [0052]      FIG. 7  is a bottom view of the personal computer; 
           [0053]      FIG. 8  is an internal block diagram of the personal computer; 
           [0054]      FIG. 9  is a rear view of the personal computer from which an upper rear case is removed; 
           [0055]      FIG. 10  is a rear view of the personal computer from which the upper rear case and the lower rear case are removed; 
           [0056]      FIG. 11  is a perspective view of the sheet metal frame on which a printed circuit board is mounted and the lower front case; 
           [0057]      FIG. 12  is a perspective view of the sheet metal frame from which the printed circuit board is removed and the lower front case  12 A; 
           [0058]      FIG. 13  is an exploded view of the sheet metal frame and the lower front case; 
           [0059]      FIG. 14  is an enlarged view of the lower front case in the vicinity of the fixed position P; 
           [0060]      FIG. 15  is an enlarged view of the front face side of the sheet metal frame to which the lower front case is fixed; 
           [0061]      FIG. 16  is an enlarged rear view of the sheet metal frame; 
           [0062]      FIG. 17  is an enlarged view of the sheet metal frame, to which the lower front case is fixed, in the vicinity of the fixed positions P, Q and R; 
           [0063]      FIG. 18  is a cross section of a portion where the upper hook of the lower front case is engaged with the hook hole of the sheet metal frame; 
           [0064]      FIG. 19  is a cross section of a portion where the projection of the lower front case is engaged with the projection hole of the sheet metal frame; 
           [0065]      FIG. 20  is a cross section of the protrusion of the sheet metal frame; and 
           [0066]      FIG. 21  is a schematic diagram for describing a method of attaching the lower front case to or detaching the lower front case from the sheet metal frame. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0067]    A concrete embodiment of the component assembly and the electronic apparatus will be described below with reference to the drawings. 
         [0068]      FIG. 4  is an appearance of a personal computer  100  being a first concrete embodiment of an electronic apparatus. 
         [0069]    The personal computer  100  is an integral unit which includes a display device for displaying information, a hard disk device and a CPU together in the same housing. Incidentally, although a keyboard, a mouse and the like are actually connected to the personal computer  100 , they are omitted from  FIG. 4 . 
         [0070]      FIG. 4  is the front perspective view of the personal computer  100 . The personal computer  100  includes a liquid crystal panel on the surface of which a display screen  21  spreads, a CPU, a hard disk device, a cooling fun, a power supply device, various boards and cables for connecting the components together in the space formed by an upper front case  11 A, an upper rear case  11 B, a lower front case  12 A and a lower rear case  12 B. The combination of the upper front case  11 A, the upper rear case  11 B, the lower front case  12 A and the lower rear case  12 B corresponds to one example of the housing in the basic feature described above. 
         [0071]    On the front face of the personal computer  100 , there are provided a start switch  34   a  for starting the personal computer  100 , a display switch  34   b  for displaying information on the display screen  21  and the like. On one side of the personal computer  100 , there are provided an optical disk loading slot  31  for loading an optical disk such as a CD or a DVD and an FD loading slot  32  for loading a flexible disk (hereinafter, referred to as “FD”). 
         [0072]      FIG. 5  is a side elevation of the personal computer  100  and  FIG. 6  is a rear elevation of the personal computer  100 . 
         [0073]    In the personal computer  100 , the upper rear case  11 B is attached to the upper front case  11 A and the lower rear case  12 B is attached to the lower front case  12 A. Into the upper front case  11 A, there is fitted a liquid crystal panel with the display screen  21  in front. On the other side of the display screen  21 , there is housed a hard disk device, various board and the like. On the rear face of the personal computer  100 , there are provided a main power switch  40  for turning on power and an expansion card loading slot  33  for loading an expansion card for expanding functions such as a LAN card. 
         [0074]      FIG. 7  is a bottom view of the personal computer  100 . 
         [0075]    In an upper part of the inside of the personal computer  100 , there is housed a replaceable hard disk device and the like. Under the inside thereof, there is housed a normally irreplaceable board and the like while being protected by the housing frame. For example, the lower front case  12 A is a replaceable plastic cover. A printed circuit board is attached to a metallic housing frame (refer to  FIG. 10 ). The housing frame is fixed to the lower front case  12 A with screws  50 . In the typical repair of the personal computer  100 , only the upper rear case  11 B is removed from the upper front case  11 A and a hard disk device housed above the inside thereof is replaced. 
         [0076]      FIG. 8  is an internal block diagram of the personal computer  100 . 
         [0077]    As illustrated in  FIG. 8 , the personal computer  100  includes a CPU  101  for executing various programs, a main memory  102  in which a program stored in a hard disk device  103  is read and developed to execute it by the CPU  101 , the hard disk device  103  for storing various programs and data, a loudspeaker device  104  for generating audio signal to output an audio, an input interface  105  to which data is input from an external device, an operator  106  such as a keyboard and a track pad, a display device  107  for displaying information on the display screen  21 , an FD drive  108  onto which an FD  61  is loaded and which accesses the loaded FD  61 , a CD/DVD drive  109  onto which a CD-ROM  62  or a DVD is loaded and which accesses the loaded CD-ROM  62  or DVD, an output interface  110  for outputting data to an external device and a communication interface  111  for communicating using an expansion card  63 . The above various elements are interconnected through a bus  112 . 
         [0078]    As described above, the personal computer  100  is formed such that electronic components such as a printed circuit board are attached to the metallic housing frame and the plastic case is further attached to the housing frame to establish compatibility between strength and appearance. A method of fixing the lower front case  12 A to the housing frame will be described in detail below. 
         [0079]      FIG. 9  is a rear view of the personal computer  100  from which the upper rear case  11 B is removed. 
         [0080]    As illustrated in  FIG. 9 , into the upper front case  11 A, there is fitted a liquid crystal panel  210  with the display screen  21  illustrated in  FIG. 8  in front. On the other side of the liquid crystal panel  210 , there are arranged in overlap a control board  211  for controlling the liquid crystal panel  210 , a main board  220  on which the communication interface  111  and the hard disk device  103  and the like illustrated in  FIG. 8  are mounted, a power supply device  230  for controlling electric power and the like. The personal computer  100  is partitioned into an upper and a lower portion by a partitioning frame  240  being part of the housing frame. Under the partitioning frame  240 , there are housed a printed circuit board  260  (refer to  FIG. 10 ) on which the loudspeaker device  104  (refer to  FIG. 8 ), various switches  34   a  and  34   b  (refer to  FIG. 4 ) and the like are mounted. The main board  220  is connected to the printed circuit board  260  by a wide flat cable  250  with a flat conductor. The flat cable  250  attached to the printed circuit board  260  is attached to a connector  221  provided on the main board  220  through a through hole  241  formed in the partitioning frame  240 . 
         [0081]      FIG. 10  is a rear view of the personal computer  100  from which the upper rear case  11 B and the lower rear case  12 B are removed. 
         [0082]    As illustrated in  FIG. 10 , on the other side of the lower front case  12 A, there is provided a cooling fan  270 . Although not illustrated in the  FIG. 10 , the CPU  101  illustrated in  FIG. 8  is arranged between the power supply device  230  and the cooling fan  270 . Heat generated by the power supply device  230  and the CPU  101  is cooled by air introduced by the cooling fan  270 . The lower front case  12 A is fixed to a sheet metal frame  255  being part of the housing frame with a screw. Under the partitioning frame  240 , there is housed the printed circuit board  260  fixed to the sheet metal frame  255 . The flat cable  250  attached to the printed circuit board  260  is wired above the frame  240  through a recess  242  formed in the frame  240  and the through hole  241  illustrated in  FIG. 9 . The lower front case  12 A corresponds to one example of the “first component” in the basic feature of the present invention. The sheet metal frame  255  corresponds to one example of the second component in the basic feature according to the present invention. 
         [0083]      FIG. 11  is a perspective view illustrating the sheet metal frame  255  on which the printed circuit board  260  is mounted and the lower front case  12 A. 
         [0084]    The printed circuit board  260  is attached to the sheet metal frame  255  with the surface on which a connector for the flat cable  250  is provided opposing the lower front case  12 A. The flat cable  250  is routed such that one terminal  251  thereof is mated with a connector provided on the front face of the printed circuit board  260 , a wiring section  252  thereof passes through a through hole  261  provided in the printed circuit board  260  and is extended above the frame  240  illustrated in  FIGS. 9 and 10  through the other side of the printed circuit board  260  and the other terminal  251  thereof is mated with the connector  221  of the main board  220  illustrated in  FIGS. 9 and 10 . 
         [0085]    On the front face of the printed circuit board  260  opposing the lower front case  12 A, there are provided the start switch  34   a  and the display switch  34   b  illustrated in  FIG. 4 . 
         [0086]      FIG. 12  is a perspective view illustrating the sheet metal frame  255  from which the printed circuit board  260  is removed and the lower front case  12 A.  FIG. 13  is an exploded view of the sheet metal frame  255  and the lower front case  12 A. 
         [0087]    As illustrated in  FIG. 12 , in the sheet metal frame  255  and the lower front case  12 A, there are provided through holes  310  and  410  for exposing the start switch  34   a  and the display switch  34   b  provided on the printed circuit board  260  to the outside. The start switch  34   a  and the display switch  34   b  correspond to one example of the “third component” of in the additional feature of the present invention. The through hole  310  formed in the sheet metal frame  255  corresponds to one example of the “third hole” in the additional feature of the present invention. The through hole  410  formed in the lower front case  12 A corresponds to one example of the “hole corresponding to the third hole” in the additional feature of the present invention. 
         [0088]    Three fixed positions P, Q and R are prepared both on the left and the right side in the longitudinal direction of the sheet metal frame  255  and the lower front case  12 A. The sheet metal frame  255  and the lower front case  12 A are fixed such that firstly the lower front case  12 A is tentatively fixed to the sheet metal frame  255  at two fixed positions P and Q, and then screws  50  illustrated in  FIG. 7  are inserted into screw holes  300   a  and  400   a  formed at the fixed position R and tightened to fix the lower front case  12 A to the sheet metal frame  255 . The screw hole  300   a  formed in the sheet metal frame  255  corresponds to one example of the “screw hole” in the additional feature of the present invention. The screw hole  400   a  formed in the lower front case  12 A corresponds to one example of the “screw through hole” in the additional feature of the present invention. 
         [0089]      FIG. 13  is a rear view of the lower front case  12 A and the sheet metal frame  255 . 
         [0090]    On the lower front case  12 A, there are provided an upper hook  420  at the fixed position P illustrated in  FIG. 12 , a projection  430  projecting toward the back of the personal computer  100  and a protrusion  440  protruding upward. The upper hook  420  corresponds to one example of the “locking section” in the basic feature of the present invention. The projection  430  corresponds to one example of the “projection” in the basic feature of the present invention. The protrusion  440  corresponds to one example of the “protrusion” in the additional feature of the present invention of the present invention. 
         [0091]    In the sheet metal frame  255 , there are a hook hole  320  into which the upper hook  420  of the lower front case  12 A is inserted at the fixed position Q, a projection hole  330  into which the projection  430  of the lower front case  12 A is inserted, an interference section  340  for interfering with the projection  430  from the lower side and a protrusion  350  (see  FIGS. 16 and 17 ) under which the protrusion  440  of the lower front case  12 A enters at the fixed position P. The hook hole  320  corresponds to one example of the “first hole” in the basic feature of the present invention. The projection hole  330  corresponds to one example of the “second hole” in the basic feature of the present invention. The interference section  340  corresponds to one example of the “part” in the basic feature of the present invention. The protrusion  350  corresponds to one example of the “protrusion section fitted into a recess” in the additional feature of the present invention. 
         [0092]    The various elements provided at fixed positions P and Q will be described in detail below one by one. 
         [0093]      FIG. 14  is an enlarged view of the lower front case  12 A in the vicinity of the fixed position P. 
         [0094]    The lower front case  12 A includes a first face  401  forming the front face of the personal computer  100  and a second face  402  forming the bottom face of the personal computer  100 . A screw hole  400   a  is formed in the second face  402 . Forming the screw hole  400   a  in the second face  402  enables the lower front case  12 A to be fixed to the sheet metal frame  255  with a screw on the bottom side of the personal computer  100 , which allows improving appearance. The first face  401  corresponds to one example of the “first face of the first component” in the basic feature of the present invention. The second face  402  corresponds to one example of the “second face of the first component” in the additional feature of the present invention. 
         [0095]    The projection  430  has a plate shaped section  431  extending perpendicularly from the first face  401  and a supporting section  432  projecting from the second face  402  and supporting the plate shaped section  431  from the lower side. The upper face of the plate shaped section  431  is parallel to the second face  402 . The lower face of the plate shaped section  431  has a slope descending toward the first face  401 . The plate shaped section  431  corresponds to one example of the “slope section of the first component” in the additional feature of the present invention. The supporting section  432  corresponds to one example of the “supporting section” in the additional feature of the present invention. 
         [0096]    The protrusion  440  is provided nearby the projection  430  and protrudes upward from the second face. 
         [0097]      FIG. 15  is an enlarged view of the front face side of the sheet metal frame  255  to which the lower front case  12 A is to be fixed. 
         [0098]    The sheet metal frame  255  includes a first face  301  arranged on the front side of the personal computer  100  while opposing the first face  401  of the lower front case  12 A and a second face  302  arranged on the bottom face of the personal computer  100  while opposing the second face  402  of the lower front case  12 A. The first face  301  corresponds to one example of the “first face of the second component” in the basic feature of the present invention. The second face  302  corresponds to one example of the “second face of the second component” in the additional feature of the present invention. 
         [0099]    The hook hole  320  is formed larger than the upper hook  420  so that the upper hook  420  of the lower front case  12 A is smoothly inserted thereinto. The projection hole  330  extends both to the first face  301  and the second face  302 , so that the projection  430  of the lower front case  12 A can be easily inserted into the projection hole  330 . 
         [0100]      FIG. 16  is an enlarged rear view of the sheet metal frame  255 . 
         [0101]    As illustrated in  FIG. 16 , the interference section  340  of the sheet metal frame  255  is formed of a platform section  341  projected from the second face  302  and a slope section  342  extending from the platform section  341  and descending toward the first face  301 . The slope section  342  corresponds to one example of the “slope section of the second component” in the basic feature of the present invention. The platform section  341  corresponds to one example of the “portion regulating the displacement of a projection of the first component” in the additional feature of the present invention. 
         [0102]    The protrusion  350  is provided on the second face  302  and protrudes upward, and the bottom face  351  thereof enters the inside. 
         [0103]      FIG. 17  is an enlarged view of the sheet metal frame  255 , to which the lower front case  12 A is fixed, in the vicinity of the fixed positions P, Q and R. 
         [0104]    As illustrated in  FIG. 17 , the upper hook  420  of the lower front case  12 A is engaged in the hook hole  320  of the sheet metal frame  255  at the fixed position Q. The projection  430  of the lower front case  12 A is inserted into the projection hole  330  of the sheet metal frame  255  and abuts the interference section  340  at the fixed position P. 
         [0105]      FIG. 18  is a cross section of a portion where the upper hook  420  of the lower front case  12 A is engaged in the hook hole  320  of the sheet metal frame  255 . 
         [0106]    As illustrated in  FIG. 18 , since the hook hole  320  is formed larger than the upper hook  420 , the upper hook  420  is loosely engaged in the hook hole  320 . Before the fixed position P is fixed, the lower front case  12 A can be rotated in the arrow direction A with the upper hook  420  being engaged in the hook hole  320 . 
         [0107]      FIG. 19  is a cross section of a portion where the projection  430  of the lower front case  12 A is engaged in the projection hole  330  of the sheet metal frame  255 . 
         [0108]    The lower front case  12 A is rotated in the arrow direction A to cause the slope section  342  of the sheet metal frame  255  to push the plate shaped section  431  of the lower front case  12 A upward with the lower front case  12 A being moved in the arrow direction B. The direction in which the lower front case  12 A is pushed upward corresponds to one example of the “first direction” in the basic feature of the present invention. 
         [0109]    The lower face of the plate shaped section  431  provided on the projection  430  of the lower front case  12 A has a slope descending toward the front thereof, so that the lower front case  12 A is further rotated in the arrow direction B to cause the platform section  341  of the sheet metal frame  255  to enter the lower side of the plate shaped section  431  of the lower front case  12 A to interfere therewith, regulating the displacement of the lower front case  12 A. 
         [0110]      FIG. 20  is a cross section of the protrusion  350  of the sheet metal frame  255 . 
         [0111]    The bottom face  351  of the protrusion  350  of the sheet metal frame  255  is recessed inside. The protrusion  440  of the lower front case  12 A is fitted to the recess section. 
         [0112]      FIG. 21  is a schematic diagram for describing a method of attaching the lower front case  12 A to or detaching the lower front case from the sheet metal frame  255 . 
         [0113]    As illustrated in Part (A) of  FIG. 21 , when the lower front case  12 A is attached to the sheet metal frame  255 , the engagement of the upper hook  420  with the hook hole  320  presses the sheet metal frame  255  in the arrow direction “m” and the abutment of the plate shaped section  431  of the lower front case  12 A on the platform section  341  of the sheet metal frame  255  presses the plate shaped section  431  of the lower front case  12 A in the arrow direction “l”. In addition, the protrusion  440  of the lower front case  12 A is fitted to the protrusion  350  of the sheet metal frame  255  to cause the protrusion  440  of the lower front case  12 A to press the sheet metal frame  255  in the arrow directions i, j and k. Thus, the lower front case  12 A is surely fixed to the sheet metal frame  255 . Tightening the screws  50  in this condition prevents erroneous attachment and the like. 
         [0114]    As illustrated in Part (B) of  FIG. 21 , a force is applied to the lower front case  12 A in the arrow direction B to move the plate shaped section  431  of the lower front case  12 A downward along the slope section  342  of the sheet metal frame  255  to detach the protrusion  440  of the lower front case  12 A from the protrusion  350  of the sheet metal frame  255 , thereby rotating the lower front case  12 A around the upper hook  420  in the arrow direction A. At this time, an excessive force is not applied to the upper hook  420  of the lower front case  12 A and the interference section  340  formed of plastics material low in strength to enable a smooth attachment/detachment and the prevention of wear and damage. Thus, according to the present embodiment, the lower front case  12 A can be repetitively attached and detached. 
         [0115]    When the lower front case  12 A is attached to the sheet metal frame  255 , as illustrated in Part (C) of  FIG. 21 , even if the lower front case  12 A is attempted to rotate in the arrow direction A′ in the condition that the upper hook  420  is incorrectly inserted into the hook hole  320 , the plate shaped section  431  of the lower front case  12 A enters under the slope section  342  of the sheet metal frame  255 , as a result, the lower front case  12 A cannot be pressed upward any more. In the present embodiment, as illustrated in  FIG. 7 , since the screw holes  300   a  and  400   a  used for fixing the lower front case  12 A to the sheet metal frame  255  with the screws are formed in the same bottom side of the personal computer  100  as the protrusions  350  and  440 , the screw holes  300   a  and  400   a  do not communicate with each other in the condition of Part (C) of  FIG. 21 , resultantly, the screws cannot be tightened. Thus, in the present embodiment, it is possible to surely prevent the lower front case  12 A from being erroneously attached to the sheet metal frame  255 . 
         [0116]    Although the personal computer is taken as one example of the electronic apparatus described in “SUMMARY OF THE INVENTION” herein, the electronic apparatus may be a television receiver, a cellular phone or the like as long as it is such an apparatus that attaches a cover to a housing frame.