Abstract:
A first housing of an electronic device is connected to a second housing of the electronic device in a slidable manner. A rack is positioned on the first housing. A gear unit and a hinge are positioned on the second housing. The gear unit engages with the rack, and a gear positioned at an end of the hinge engages with the gear unit.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention provides an electronic device having a slidable cover, in particular an electronic device having a slidable cover that slides via a rack. 
         [0003]    2. Description of the Prior Art 
         [0004]    Please refer to  FIG. 1  to  FIG. 4 .  FIG. 1  to  FIG. 4  present a sliding structure  1  inside a cellphone having a slidable cover in the prior art. The sliding structure  1  comprises a main board  10 , a moving board  12  and a torsional spring  14 . The torsional spring  14  comprises four connecting points with two of the connecting points placed on fixing points  11 ,  13  on the main board  10  and the other two connecting points placed on fixing points  15 ,  17  on the moving board  12 . The main board  10  comprises two rails  16  and the moving board  12  also comprises two rails  18  (as in  FIG. 4 ) that are used to connect with the rails  16  of the main board  10 . 
         [0005]    As the sliding structure  1  is in a situation shown in  FIG. 1 , the elastic potential energy of the torsional spring  14  is fully released. If a force is applied to the moving board  12 , the torsional spring  14  is compressed. When the torsional spring  14  is compressed to a maximum, as displayed in  FIG. 2 , the torsional spring stores a maximum elastic potential energy. With a conversion from the elastic potential energy to kinetic energy, the moving board  12  can move to another side of the main board  10 , as shown in  FIG. 3 . 
         [0006]    The prior art uses a torque of the torsional spring to move a sliding cover of a cellphone. However, the sliding structure  1  in  FIG. 1  needs a large area when realized in a cellphone and cellphone design therefore needs to be compromised because the prior art cannot agree with a trend of cellphones getting smaller and smaller. 
       SUMMARY OF THE INVENTION 
       [0007]    An electronic device having a sliding cover is disclosed. The electronic device comprises a first housing, a second housing, a rack disposed on the first housing, and a hinge disposed on the second housing. An end of the hinge is connected to a first gear, which meshes with the rack. The hinge comprises a first cam coupled to the first gear, a second cam disposed under the first cam and connected to the first cam, and an elastic component disposed under the second cam. When the second housing slides along a first direction due to a push force corresponding to the first housing, the first cam is caused to rotate along a first rotational direction in relation to the second cam with the elastic component providing an elastic force to the second cam so that as the push force vanishes, the first cam rotates along a direction that is the same as the first rotational direction in relation to the second cam. 
         [0008]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  to  FIG. 4  present a sliding structure inside a cellphone having a slidable cover in the prior art. 
           [0010]      FIG. 5  is an exploded diagram of a sliding structure that is an embodiment of the present invention. 
           [0011]      FIG. 6  is a diagram combining components of the sliding structure in  FIG. 5 . 
           [0012]      FIG. 7  and  FIG. 8  are diagrams of motions of the sliding structure. 
           [0013]      FIG. 9  and  FIG. 10  are diagrams of the sliding structure realized as an electronic device having a sliding cover. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Please refer to  FIG. 5 .  FIG. 5  is an exploded diagram of a sliding structure  5  that is an embodiment of the present invention. The sliding structure  5  comprises a rack  52 , a gear unit  54  and a hinge  56 . The hinge comprises a first gear  561 , a first cam  562 , a second cam  563 , a spring  564 , a bolt  565  and a housing  566 . The gear unit  54  comprises a second gear  541  and a third gear  542  where the second gear  541  and the third gear  542  share a same axis. 
         [0015]    Please refer to  FIG. 6 .  FIG. 6  is a diagram combining components of the sliding structure  5  in  FIG. 5 . The first cam  562 , the second cam  563 , the spring  564  and the bolt  565  are placed inside the housing  566 . The bolt  565  is placed inside the spring  564 ; the second cam  563  slides along the bolt  565  through a link with the first cam  562 . With the sliding of the second cam  563  the spring  564  is compressed. The rack  52  meshes with the second gear  541  of the gear unit  54 , and the first gear  561  of the hinge  56  meshes with the third gear  542  of the gear unit  54 . 
         [0016]      FIG. 7  and  FIG. 8  are diagrams of motions of the sliding structure  5 . When the rack  52  moves, which drives the gear unit  54  to rotate, and the first gear  561  of the hinge  56  rotates. Since the first cam  562  shares the same axis as the first gear  561 , the first cam  562  and the second cam  563  starts rotating. While rotating, the second cam slides downwards and compresses the spring  564  (as in  FIG. 7 ). 
         [0017]    When in a situation as shown in  FIG. 7 , removing the force on the rack  52  allows using the hinge  56  to drive the gear unit  54  to rotate and the rack  52  to move. With a rebound of the spring  564 , the second cam  563  slides upwards and continues to rotate in correspondence to the first cam  562 . The first cam  562  continues to rotate and drives the gear unit  54  to rotate, hence moving the rack  52 . When the spring  564  recovers to its original length, all the rotating and moving stops, as shown in  FIG. 8 . 
         [0018]    Please refer to  FIG. 9  and  FIG. 10 .  FIG. 9  and  FIG. 10  are diagrams of the sliding structure  5  realized as an electronic device having a sliding cover  9 . The electronic device having a sliding cover  9  comprises a first housing  92  and a second housing  94 . The first housing  92  comprises a display monitor  91 , and inside the first housing  92  is a first fixing component  95 . Inside the second housing  94  is a second fixing component  96  and a third fixing component  98 . The rack  62  of the sliding structure  5  is placed on the first housing  92 , while the gear unit  54  and the hinge  56  are placed on the second housing  94 . 
         [0019]    The first fixing component  95  of the first housing  92  in  FIG. 9  detachably connects with the second fixing component  96  of the second housing  94  to fix relative locations of the first housing  92  and the second housing  94 . After completing the motion of the sliding structure  5 , as in  FIG. 10 , the first fixing component  95  of the first housing  92  detachably connects and fixes with the third fixing component  98  of the second housing  94  to fix final relative locations of the first housing  92  and the second housing  94  after the first housing has been fully extended. 
         [0020]    The sliding structure of the embodiment of the present invention does not occupy a large area and an overall length can be adjusted with different matching springs, so that a thickness of an electronic device occupied by the sliding structure can be altered according to design requirements. Therefore design of the electronic device can be decreased, agreeing with a current trend. 
         [0021]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.