Abstract:
There is provided a communication device that includes a first housing with a rail and a slider, the rail and the slider being capable of engaging with each other, and a second housing including a hook which engages with the slider to combine the first and the second housings each other when the first housing is slid above the second housing along a first direction, the hook being disengaged with the slider to release the first housing from the second housing according to an operation including a motion in which the first housing is slid above the second housing along a second direction different from the first direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2010-222581, filed on Sep. 30, 2010, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The present embodiments relate to a communication device for information communication and a method of combining and releasing housings which include electronic elements. 
       BACKGROUND 
       [0003]    A separable type mobile phone, including two housings capable of being combined with each other and released from each other, have recently been developed. One of the housings is a display unit and the other housing is a keypad unit. A typical separable type mobile phone is able to establish communication connection between the display and the keypad units by use of communication based on to a short-range wireless standard, such as Bluetooth (registered trademark). The two housings may be slidable over each other while the two housings are combined with each other. 
         [0004]    Since the display unit and the keypad unit may be used in a manner that these units are released from each other, a user may use these units in a free arrangement. For example, a user may browse a website on the display unit while talking on the phone through the keypad unit. Such a mobile phone is attracting attention as a new mobile phone model capable of providing a variety of services. 
         [0005]    Slidable type mobile phones having a magnetic coupling function are disclosed in, for example, Japanese Laid-open Patent Publication Nos. 2002-176478 and 2003-348204. 
       SUMMARY 
       [0006]    According to an aspect of the invention, a communication device includes a first housing including a rail and a slider, the rail and the slider being capable of engaging with each other, and a second housing including a hook which engages with the slider to combine the first and the second housings each other when the first housing is slid above the second housing along a first direction, the hook being disengaged with the slider to release the first housing from the second housing according to an operation including a motion in which the first housing is slid above the second housing along a second direction different from the first direction. 
         [0007]    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. 
         [0008]    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 
         [0009]      FIGS. 1A to 1C  are diagrams illustrating an exemplary configuration of a communication device; 
           [0010]      FIG. 2  is a diagram illustrating the communication device in its slide closed state; 
           [0011]      FIG. 3  is a diagram illustrating the communication device in its slide open state; 
           [0012]      FIG. 4  is a diagram illustrating the communication device in its separated state; 
           [0013]      FIG. 5  is a diagram illustrating the internal structure of an upper housing as viewed from the rear surface thereof; 
           [0014]      FIG. 6  is a diagram illustrating a sliding operation for combining the upper housing with a lower housing; 
           [0015]      FIG. 7  is a diagram illustrating the sliding operation for combining the upper housing with the lower housing; 
           [0016]      FIG. 8  is a diagram illustrating the sliding operation for combining the upper housing with the lower housing; 
           [0017]      FIG. 9  is a diagram illustrating the internal structures of the upper and lower housings while being combined with each other; 
           [0018]      FIG. 10  is a diagram illustrating a lock mechanism; 
           [0019]      FIG. 11  is a diagram illustrating state transition until a hook and a sliding member are locked; 
           [0020]      FIG. 12  is a diagram illustrating state transition until the hook and the sliding member are locked; 
           [0021]      FIG. 13  is a diagram illustrating state transition until the hook and the sliding member are locked; 
           [0022]      FIG. 14  is a diagram explaining a separation button; 
           [0023]      FIG. 15  is a diagram explaining the separation button; 
           [0024]      FIG. 16  is a diagram illustrating a button-based hook pushing mechanism; 
           [0025]      FIG. 17  is a diagram illustrating the button-based hook pushing mechanism; 
           [0026]      FIG. 18  is a diagram illustrating an exemplary shape of a hook pushing guide; 
           [0027]      FIG. 19  is a diagram illustrating an action of a hook pushing pin; 
           [0028]      FIG. 20  is a diagram illustrating the action of the hook pushing pin; and 
           [0029]      FIG. 21  is a longitudinal sectional view of another communication device. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     Preliminary Consideration 
       [0030]    The separable type mobile phone described in the background, however, the display and the keypad units is easily disconnected from each other, for example, in sliding operation. Disadvantageously, the ease of operation is not good. 
         [0031]    The present embodiments have been made in consideration of the above-described disadvantage. Accordingly, it is an object in one aspect of the embodiment to provide a communication device with an improved mechanism for ease of operation when combining and releasing the housings. 
         [0032]    Another object in an other aspect of the embodiment is to provide a method of combining and releasing the housings with improved operability of combining and releasing the housings. 
       Embodiments 
       [0033]    An embodiment of the present invention will be described below with reference to the drawings.  FIGS. 1A to 1C  illustrate an exemplary configuration of a communication device. The communication device  1  includes an upper housing  10  including electronic elements, corresponding to a first housing, and a lower housing  20  including electronic elements, corresponding to a second housing such that the upper housing  10  may be combined with and released from the lower housing  20 . 
         [0034]    The upper housing  10  and the lower housing  20  each have an independent communication function. Accordingly, for example, while the housings  10  and  20  are combined with each other, the communication device  1  functions as a normal mobile phone. While the housings  10  and  20  are separated from each other, for example, a user may use the Internet through the upper housing  10  and talk on the phone through the lower housing  20 . The upper housing  10  and the lower housing  20  may communicate with other terminals separately and may also communicate with each other. 
         [0035]    The upper housing  10  includes, for example, a display unit  10 A on the front surface (hereinafter, also referred to as a “display surface”) thereof. On the rear surface of the upper housing  10 , the housing  10  includes a rail  11  and a sliding member  12  as illustrated in  FIG. 1C . The sliding member  12  is engaged with the rail  11  and is slid thereon. 
         [0036]    The lower housing  20  includes, for example, a keypad unit  20 A on the front surface (hereinafter, also referred to as a “keypad surface”). As illustrated in  FIG. 1B , the lower housing  20  further includes, in upper part of the front surface, hooks  21 - 1  and  21 - 2  which are engaged with the sliding member  12  to combine the lower housing  20  with the upper housing  10 . 
         [0037]    When an operation is performed such that the upper housing  10  is brought into contact with the lower housing  20  and is slid in one direction relative to the lower housing  20 , the hooks  21 - 1  and  21 - 2  are engaged with the sliding member  12 , so that the upper housing  10  is combined with the lower housing  20 . 
         [0038]    When an operation is performed such that the upper housing  10  is slid in the other direction relative to the lower housing  20 , the hooks  21 - 1  and  21 - 2  are disengaged from the sliding member  12 , so that the upper housing  10  is separated from the lower housing  20 . 
         [0039]    An exemplary appearance of the communication device  1  will now be described.  FIG. 2  illustrates the communication device  1  in its slide-closed state. In this slide-closed state, the lower housing  20 , serving as a fixed housing, is combined with the upper housing  10 , serving as a housing movable relative to the lower housing  20 . 
         [0040]    The front surface of the upper housing  10  is provided with the display unit  10 A, such as a liquid crystal display (LCD). A side surface of the upper housing  10  is provided with a separation button  30  which is pushed to separate the upper housing  10  from the lower housing  20 . The function of the separation button  30  will be described in detail below. 
         [0041]      FIG. 3  illustrates the communication device  1  in its slide open state. In this state, the upper housing  10  is slid relative to the lower housing  20 . When the upper housing  10  is slid upward relative to the lower housing  20 , the keypad unit  20 A provided for the lower housing  20  is revealed. 
         [0042]      FIG. 4  illustrates the communication device  1  in its separated state or released state. In this state, the upper housing  10  is separated from the lower housing  20 . The lower housing  20  includes two hook storage portions  2 - 1  and  2 - 2  arranged in upper part of the front surface thereof. The hook storage portions  2 - 1  and  2 - 2  store the hooks  21 - 1  and  21 - 2 , respectively. To combine the lower housing  20  with the upper housing  10 , the hooks  21 - 1  and  21 - 2  protrude out of the hook storage portions  2 - 1  and  2 - 2 , respectively, to combine the lower housing  20  with the upper housing  10 . 
         [0043]    While the upper housing  10  is separated from the lower housing  20 , the hooks  21 - 1  and  21 - 2  are respectively received in the hook storage portions  2 - 1  and  2 - 2  at all times. For example, if the keypad surface of the lower housing  20  faces downward, the hooks  21 - 1  and  21 - 2  do not protrude out of the hook storage portions  2 - 1  and  2 - 2 . The hook storage will be described later. 
         [0044]    A slide mechanism provided for the upper housing  10  will now be described.  FIG. 5  illustrates the internal structure of the upper housing  10 A viewed from the rear surface thereof where the display unit  10 A of the upper housing  10  is not disposed. 
         [0045]    The upper housing  10  is provided with the rail  11 , the sliding member  12 , slide lubricating members  12 A- 1  and  12 A- 2 , hook attraction magnets  13 - 1  and  13 - 2 , and a slide assist spring (guitar spring)  14 . 
         [0046]    The slide lubricating members  12 A- 1  and  12 A- 2  are attached to both ends of the sliding member  12 . The sliding member  12  is engaged with the rails  11  through the slide lubricating members  12 A- 1  and  12 A- 2 . 
         [0047]    One end of the slide assist spring  14  is connected to the sliding member  12  and the other end thereof is connected to the rear surface of the upper housing  10 , such that the sliding member  12  is held by the slide assist spring  14 . The upper housing  10  is further provided with the hook attraction magnets  13 - 1  and  13 - 2  configured to attract the above-described hooks  21 - 1  and  21 - 2  provided for the lower housing  20  when the housings are combined with each other. 
         [0048]    A sliding operation performed to combine the upper housing  10  with the lower housing  20  will now be described.  FIGS. 6 to 8  are diagrams, from a lateral view, illustrating the sliding operation for combining the upper housing  10  with the lower housing  20 .  FIG. 6  illustrates a state where the upper housing  10  is separated from the lower housing  20 . At this time, each hook  21  is received in the corresponding hook storage portion  2  in the lower housing  20 . 
         [0049]      FIG. 7  illustrates a state where the upper housing  10  is slid downward while the rear surface of the upper housing  10  is in contact with the front surface (keypad side) of the lower housing  20 . Each hook storage portion  2  in the lower housing  20  is positioned under the corresponding hook attraction magnet  13  provided for the upper housing  10  and the hook  21  is drawn from the hook storage portion  2 . 
         [0050]    To combine the upper housing  10  with the lower housing  20 , these housings are aligned for combination and the upper housing  10  is slid downward relative to the lower housing  20 . At this time, the hook  21  received in the hook storage portion  2  is drawn by magnetic force of the hook attraction magnet  13 . 
         [0051]      FIG. 8  illustrates a state where the upper housing  10  is combined with the lower housing  20 . The hook  21  drawn by the magnetic force of the hook attraction magnet  13  is engaged with the sliding member  12  in the upper housing  10  as the upper housing  10  is slid in a direction indicated by the arrow in  FIG. 7  relative to the lower housing  20 , so that the upper housing  10  is combined with the lower housing  20 . The combination will be described in detail later. 
         [0052]    The sliding member  12  is slidable upward and downward on the rail  11 . The sliding operation, described above with reference to  FIG. 3 , performed while the upper housing  10  is combined with the lower housing  20  allows the upper housing  10  to be slid relative to the lower housing  20  while being combined with the lower housing  20  and being held in a range where the slide assist spring  14  is movable. 
         [0053]    The combination of the upper housing  10  and the lower housing  20  will now be described.  FIG. 9  illustrates the internal structures of the upper housing  10  and the lower housing  20  while being combined with each other.  FIG. 9  is a cross-sectional view of the housings taken along the line IX-IX in  FIG. 2  and illustrates a state where the hooks  21 - 1  and  21 - 2  are attracted to the respective magnets provided for the upper housing  10 . 
         [0054]    The lower housing  20  includes the hook storage portions  2 - 1  and  2 - 2 . The hooks  21 - 1  and  21 - 2  are received in the hook storage portions  2 - 1  and  2 - 2 , respectively. The hook storage portions  2 - 1  and  2 - 2  are spaces for enclosing the hooks  21 - 1  and  21 - 2  in the lower housing  20  when the housings are separated from each other. The bottom surfaces of the hook storage portions  2 - 1  and  2 - 2  are provided with hook storage magnets  22 - 1  and  22 - 2 , respectively. 
         [0055]    The hook storage magnets  22 - 1  and  22 - 2  are magnets having a low magnetic force for receiving the hooks  21 - 1  and  21 - 2  in the hook storage portions  2 - 1  and  2 - 2 , respectively. The hook storage magnets  22 - 1  and  22 - 2  prevent the hooks  21 - 1  and  21 - 2  from easily protruding out of the hook storage portions  2 - 1  and  2 - 2  under their own weights when the housings are separated or released from each other. Furthermore, since the protrusions used for combining the housings do not appear in the lower housing  20  upon separation of the housings, the appearance of the housing is not degraded. 
         [0056]    The upper housing  10  has a two-layer structure. A first layer receives the display unit  10 A. A second layer receives mechanical components for combination and separation of the housings, e.g., the rail  11 , the sliding member  12 , the slide lubricating members  12 A, the hook attraction magnets  13 - 1  and  13 - 2 , the slide assist spring  14 , and et al. 
         [0057]    The sliding member  12  is engaged with the rail  11  through the slide lubricating members  12 A. The engagement of the sliding member  12  with the rail  11  through the slide lubricating members  12 A reduces frictional resistance between the sliding member  12  and the rail  11 , thus allowing smooth sliding. 
         [0058]    The slide lubricating members  12 A may be shaped in preferable form because the members are made of, for example, chemical resin. Accordingly, when the slide lubricating members  12 A are processed into such a shape that the clearance between the sliding member  12  and the rail  11  is reduced and the resultant slide lubricating members  12 A are arranged, the play between the sliding member  12  and the rail  11  may be reduced. 
         [0059]    The hook attraction magnets  13 - 1  and  13 - 2 , serving as magnets for attracting the hooks  21 - 1  and  21 - 2 , have a magnetic force higher than that of the hook storage magnets  22 - 1  and  22 - 2 . 
         [0060]    When the hook attraction magnets  13 - 1  and  13 - 2  approach the hooks  21 - 1  and  21 - 2 , the hooks  21 - 1  and  21 - 2  received in the hook storage portions  2 - 1  and  2 - 2  are drawn therefrom. 
         [0061]    The sliding member  12  is further provided with hook catch recesses  12 B- 1  and  12 B- 2  for catching the hooks  21 - 1  and  21 - 2 , respectively. The hooks  21 - 1  and  21 - 2  pulled upward by the magnetic force of the hook attraction magnets  13 - 1  and  13 - 2  are caught by the hook catch recesses  12 B- 1  and  12 B- 2 , respectively. 
         [0062]    As described above, since the hook attraction magnets  13 - 1  and  13 - 2  having a magnetic force higher than that of the hook storage magnets  22 - 1  and  22 - 2  are provided for the upper housing  10 , the hooks  21 - 1  and  21 - 2  may be drawn by a simple operation when the housings are combined with each other. Thus, ease of operation for a user may be improved. 
         [0063]    A lock mechanism between the sliding member  12  and the hooks  21 - 1  and  21 - 2  will now be described. When the upper housing  10  is combined with the lower housing  20 , the hooks  21 - 1  and  21 - 2  are drawn from the lower housing  20  and are engaged with the hook catch recesses  12 B- 1  and  12 B- 2 , respectively, so that the hooks  21 - 1  and  21 - 2  are connected to the sliding member  12 . In this state, however, the hooks  21 - 1  and  21 - 2  are not completely secured to the sliding member  12  because the hooks  21 - 1  and  21 - 2  are hung on the sliding member  12 . 
         [0064]    A lock mechanism is therefore provided which allows the upper housing  10  to be slid relative to the lower housing  20  from a position, where the hooks  21 - 1  and  21 - 2  are engaged with the hook catch recesses  12 B- 1  and  12 B- 2  such that the hooks are hung on the sliding member  12 , to lock the sliding member  12 . 
         [0065]    For example, the lock mechanism is provided which allows the upper housing  10  to be slid up to a position, where the leading end of the upper housing  10  is aligned with that of the lower housing  20  such that the leading ends are flush with each other, to lock the hook  21 - 1  to the sliding member  12 . 
         [0066]      FIG. 10  illustrates the lock mechanism and illustrates the internal structures of the housings as viewed in the direction of the arrow B in  FIG. 2 . In  FIG. 10 , the separation button  30  is not illustrated. The hook  21  is provided with a lock spring  23 . The sliding member  12  has a lock groove  12 C. 
         [0067]    While the hook  21  is engaged with the hook catch recess such that the hook is hung on the sliding member  12 , the upper housing  10  is further slid relative to the lower housing  20 . Consequently, the lock spring  23  attached to the hook  21  is engaged with the lock groove  12 C in the sliding member  12 . Thus, the hook  12  is completely secured to the sliding member  12 . 
         [0068]      FIGS. 11 to 13  illustrate state transition until the hook  21  and the sliding member  12  are locked. The lock spring  23  is attached to the upper surface of the hook  21 . The sliding member  12  has a notch, serving as the lock groove  12 C. The lock spring  23  includes a projection  23 A and an arm  23 B. The function of the arm  23 B will be described later. 
         [0069]      FIG. 11  illustrates a state before the hook  21  and the sliding member  12  are locked.  FIG. 12  illustrates a state where the lock spring  23  is moved downward. When the sliding member  12  is slid in the direction indicated by the arrow, the sliding member  12  is brought into contact with an inclined surface of the lock spring  23  to press the lock spring  23 , so that the lock spring  23  is moved downward. 
         [0070]      FIG. 13  illustrates a state where the sliding member  12  is locked by the lock spring  23 . When the sliding member  12  is further slid from the state illustrated in  FIG. 12 , the projection  23 A of the lock spring  23  is engaged with the lock groove  12 C, so that the lock spring  23  is moved upward to lock the sliding member  12 . 
         [0071]    As described above, the hook  21  is provided with the lock spring  23  and the sliding member  12  has the lock groove  12 C. This lock mechanism is designed such that when the upper housing  10  is slid relative to the lower housing  20  in the sliding operation for combining the housings, the lock spring  23  is engaged with the lock groove  12 C to secure the hook to the sliding member  12 . Accordingly, the upper housing  10  may be securely combined with the lower housing  20  by a simple operation upon combination of the housings, thus increasing the ease of operation for the user. 
         [0072]    The separation button  30  will now be described. To separate the combined upper and lower housings  10  and  20 , the separation button  30  disposed on the side surface of the upper housing  10  is pushed. Thus, the combined housings may be separated from each other. 
         [0073]      FIGS. 14 and 15  are diagrams explaining the separation button  30 .  FIG. 14  is a cross-sectional view of the housings taken along the line XIV-XIV in  FIG. 2 .  FIG. 15  illustrates the internal structures of the housings as viewed in the direction of the arrow B in  FIG. 2 . Explanation of the components described above with reference to  FIG. 9  is omitted. 
         [0074]    The upper housing  10  is provided with the separation button  30  on the side surface thereof. The separation button  30  includes two protrusions, i.e., a slide fixing protrusion (first protrusion)  31  and an unlocking protrusion (second protrusion)  32 . 
         [0075]    The slide fixing protrusion  31  will now be described. If the upper housing  10  is slid relative to the lower housing  20  so that the upper housing  10  is disengaged from the hooks  21 - 1  and  21 - 2 , the sliding member  12  is moved while being engaged with the hooks  21 - 1  and  21 - 2 . Accordingly, the sliding member  12  is not disengaged from the hooks  21 - 1  and  21 - 2  in this state. To disengage the sliding member  12  from the hooks  21 - 1  and  21 - 2 , therefore, the sliding member  12  has to be fixed to the upper housing  10 . 
         [0076]    The rail  11  has a through-hole  11 A. The slide-lubricating member  12 A has a protrusion receiving recess  12 D. When the separation button  30  is pushed, the slide fixing protrusion  31  extends through the through-hole  11 A of the rail  11  and is fitted into the protrusion receiving recess  12 D. 
         [0077]    When the slide fixing protrusion  31  is fitted into the protrusion, receiving recess  12 D in this manner, the sliding member  12  secured to the slide-lubricating member  12 A is fixed to the upper housing  10 . 
         [0078]    The unlocking protrusion  32  will now be described. The lock spring  23  is used to lock the hook  21  so that the hook hung on the sliding member  12  is not disengaged from the sliding member  12  during the sliding operation. To separate the upper housing  10  from the lower housing  20 , therefore, this lock has to be unlocked after the sliding member  12  is fixed to the upper housing  10 . 
         [0079]    The lock spring  23  includes the arm  23 B as illustrated in  FIG. 11 . When the separation button  30  is pushed, an inclined surface of the unlocking protrusion  32  is brought into contact with the arm  23 B of the lock spring  23  to move the lock spring  23  downward. 
         [0080]    Consequently, the projection  23 A of the lock spring  23  is disengaged from the lock groove  12 C of the sliding member  12 , thus unlocking the sliding member  12  from the lock spring  23 . The separation button  30  is provided with a coil spring  33 . When the separation button  30  is pushed and is then released, the separation button  30  is returned to its original position by restoring force of the coil spring  33 . 
         [0081]    As described above, the slide fixing protrusion  31  fixes the sliding member  12  to the upper housing  10  and the unlocking protrusion  32  unlocks the lock between the sliding member  12  and the hook  21 . Thus, when the upper housing  10  is slid so that the upper housing  10  is disengaged from the hooks  21 , the hooks may be disengaged from the sliding member  12 . 
         [0082]    As described above, the separation button  30  is provided with the slide fixing protrusion  31  and the unlocking protrusion  32  to allow the above-described two operations for separation of the upper housing  10  and the lower housing  20 . Accordingly, pushing the single separation button  30  allows the upper housing  10  to be easily separated from the lower housing  20 , thus improving the ease of operation for the user upon separating the housings. 
         [0083]    The combination of the upper housing  10  and the lower housing  20  by a button operation will be described as a modification. In the above-described embodiment, the hooks  21  are drawn from the lower housing  20  by the magnetic force of the magnets to combine the lower housing  20  with the upper housing  10 . According to the modification, a button is pushed to move the hooks  21  upward from the lower housing  20 , thus combining the lower housing  20  with the upper housing  10 . 
         [0084]      FIGS. 16 and 17  illustrate a button-based hook pushing mechanism.  FIG. 16  illustrates a state where the hooks  21  are received.  FIG. 17  illustrates a state where the hooks  21  are pushed by a button operation. 
         [0085]    The lower housing  20  is provided with a single hook-pushing button  25  on one side surface thereof. The hook-pushing button  25  is attached to a hook-pushing guide  40 .  FIG. 18  illustrates an exemplary shape of the hook-pushing guide  40 . 
         [0086]    The hook-pushing guide  40  includes two hook-pushing guide plates  41 - 1  and  41 - 2  having hook guide grooves  42 - 1  and  42 - 2 , respectively, and is shaped such that the guide plates are connected to each other. As regards the hook guide grooves  42 - 1  and  42 - 2 , each guide groove is slanted at an angle relative to a perpendicular line. 
         [0087]    Referring again to  FIGS. 16 and 17 , one end of a hook-pushing pin  43 - 1  is fitted in the hook guide groove  42 - 1  and the other end thereof is fixed to the hook  21 - 1 . The lower housing  20  is further provided with a hook guide rib  44 - 1  that vertically guides the hook  21 - 1 . 
         [0088]    Similarly, one end of a hook-pushing pin  43 - 2  is fitted in the hook guide groove  42 - 2  and the other end thereof is fixed to the hook  21 - 2 . The lower housing  20  is further provided with a hook guide rib  44 - 2  that vertically guides the hook  21 - 2 . 
         [0089]    While the hook-pushing button  25  is not pushed as illustrated in  FIG. 16 , the hooks  21 - 1  and  21 - 2  are received in the hook storage portions  2 - 1  and  2 - 2 , respectively. Whereas, when the hook-pushing button  25  is pushed in the direction of an arrow in  FIG. 17 , the hook-pushing guide  40  is moved left to right, so that the hook guide grooves  42 - 1  and  42 - 2  are also moved in the same direction. 
         [0090]    The hook pushing pins  43 - 1  and  43 - 2  are therefore moved upward while being guided by the slanted grooves, serving as the hook guide grooves  42 - 1  and  42 - 2 . Consequently, the hooks  21 - 1  and  21 - 2  connected to the hook pushing pins  43 - 1  and  43 - 2  are pushed upward along the hook guide ribs  44 - 1  and  44 - 2 , respectively, so that the hooks protrude out of the hook storage portions  2 - 1  and  2 - 2 , respectively. 
         [0091]    When the hook-pushing button  25  is released, the hook-pushing guide  40  is returned to its original position by restoring force of a coil spring  45 . Accordingly, so long as the hooks  21 - 1  and  21 - 2  are not engaged with the sliding member  12 , the hooks  21 - 1  and  21 - 2  are received in the hook storage portions  2 - 1  and  2 - 2 , respectively. 
         [0092]      FIGS. 19 and 20  are diagrams illustrating actions of the hook-pushing pin  43 . When the hook pushing guide plate  41  is slid on a slide surface, the hook-pushing pin  43  is moved from a position P 1  to a position P 2  along the hook guide groove  42  which guides the vertical movement. 
         [0093]    As described above, the lower housing  20  is provided with the hook pushing guide  40  having the guide grooves which allow the hooks to protrude out of the respective hook receiving portions, the hook pushing pins  43  each having one end fitted in the corresponding guide groove and the other end fixed to the corresponding hook, and the hook pushing button  25  connected to the hook pushing guide  40 . 
         [0094]    When the hook-pushing button  25  is pushed, the hook-pushing guide  40  is slid in the direction in which the button is pushed, the hook pushing pins  43  are moved upward along the respective guide grooves, so that the hooks are pushed out of the respective hook storage portions. When the hook-pushing button  25  is released, the hooks are received into the lower housing  20 . 
         [0095]    Accordingly, pushing the hook pushing button  25  once during combination of the housings, namely, such a simple operation allows the hooks  21 - 1  and  21 - 2  to be drawn, thus increasing the ease of operation for the user. 
         [0096]    A modification of the sliding operation for combining the upper housing  10  with the lower housing  20  will now be described. In the foregoing embodiment, to combine the housings, the upper housing  10  is slid downward relative to the lower housing  20  to be combined therewith as illustrated in  FIGS. 6 to 8 . According to the modification, the sliding operation is reversed such that the upper housing  10  is slid upward relative to the lower housing  20  to be combined therewith. 
         [0097]      FIG. 21  is a longitudinal sectional view of a communication device according to the modification. The lower housing  20  includes the hook storage portions  2  which receive the hooks  21 , respectively. Each hook storage portion  2  is provided with the hook storage magnet  22  on the bottom surface thereof. The hook  21  is provided with the lock spring  23 . The lock spring  23  is disposed so as to have orientation opposite to that in  FIG. 10 . 
         [0098]    The upper housing  10  has a two-layer structure. A first layer receives the display unit  10 A. A second layer receives mechanical components for combination and separation of the housings, e.g., the rail  11 , the sliding member  12 , the slide lubricating members  12 A, and the hook attraction magnets  13 . 
         [0099]    With the arrangement illustrated in  FIG. 21 , the upper housing  10  is slid in the direction of an arrow relative to the lower housing  20  in order to combine the housings. Such a sliding operation for combination allows the user to easily visually recognize a state where the hooks  21  are drawn from the lower housing  20 . Thus, the user may combine the housings while recognizing how the housing is attached to the other one. 
         [0100]    As described above, the two separated housings of the communication device  1  constitute a double structure. The device is normally of the slide type in which the display unit is slidable. The communication device  1  is designed such that the housings may be easily separated through the sliding member when the separation button disposed on the upper housing is operated. While the housings are separated from each other, the appearance of the device is smart because there is no protrusion. 
         [0101]    On the rear surface of the upper housing opposite the display surface, a slide rail mechanism including the sliding member which slides on the rail while being engaged with the rail is disposed. The hooks are provided for the lower housing. The hooks are drawn by the magnets provided for the upper housing. 
         [0102]    The hooks are engaged with the recesses of the sliding member provided for the upper housing. When the upper housing is slid relative to the lower housing in this state, the hooks are completely connected to the sliding member. With this configuration, the housings may be reliably combined with each other by a simple sliding operation, thus improving the ease of operation. 
         [0103]    As regards the lock between the hook and the sliding member, the engagement sliding operation is locked by the lock spring provided for the hook. For unlocking in this case, the separation button provided for the side surface of the upper housing is pushed to unlock the lock and the upper housing is slid relative to the lower housing (in the opposite direction from that for combination) while the separation button is being pushed, so that the housings may be separated from each other. With this structure, the housings may be reliably separated from each other by a simple sliding operation, thus improving the ease of operation. 
         [0104]    The exemplary embodiment of the present invention has been described above. The components described in the embodiment may be replaced by other components having similar functions. Moreover, another component and/or step may be added. Furthermore, although the mechanism for combination and separation of the housings based on sliding operations in the longitudinal direction of the device has been described above, a similar mechanism is applicable to combination and separation of the housings based on sliding operations in the lateral direction of the device. 
         [0105]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation 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 inventions 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.