Abstract:
A support linkage movably connecting a key cap to a plastic body comprises a first rack and a second rack. The first rack has a first rack body movably connected between the key cap and the plastic body, and the second rack has a second rack body movably connected between the key cap and the plastic body. The second rack body has two axial holes each having an open side and engaged with a shaft on the first rack body.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a support linkage for keyswitch, more particularly, to a support linkage for keyswitch, which can be easily assembled and is not liable to deform or break during assembling.  
         BACKGROUND OF THE INVENTION  
         [0002]    The conventional keyset for notebook computer generally comprises a key cap  2 , a first rack  1 , a second rack  3 , a flexible circuit board  4 , a resilient body  6 , and a base plate  5 .  
           [0003]    As shown in FIG. 1 and  2 , the conventional first rack  1  and second rack  2  are arranged in scissors arrangement. When the key cap  2  is guided by the first rack  1  and the second rack  3  to move upward and downward, whereby the body  6  below the key cap  2  can press on or detach from the flexible circuit board  4  to turn on or turn off the keying.  
           [0004]    However, the lateral sides of the rack  1 ,  3  in conventional art have not sufficient strength such that the racks are liable to deform or break during assembling or detach. Moreover, the assembling of those racks is not easy and requires precise alignment to prevent jamming.  
           [0005]    It is the object of the present invention to provide a support linkage for keyswitch, the racks thereof are designed to have easy assembling without the usage of auxiliary tools, and have better strength to prevent the deforming and breaking during assembling or disassemble.  
           [0006]    To achieve the above object, the support linkage for keyswitch according to the present invention comprises a first rack and a second rack. The first rack has a first rack body movably connected between the key cap and the plastic body, and the second rack has a second rack body movably connected between the key cap and the plastic body. The second rack body has two axial holes each having an open side and engaged with a shaft on the first rack body.  
           [0007]    The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: 
       
    
    
     BRIEF DESCRIPTION OF DRAWING  
       [0008]    [0008]FIG. 1 is the perspective exploded view of the conventional keyset.  
         [0009]    [0009]FIG. 2 is the perspective view of the scissors-type tack in conventional keyset.  
         [0010]    [0010]FIG. 3 is a perspective exploded view of the preferred embodiment of the invention.  
         [0011]    [0011]FIG. 4 is the perspective view of the second rack of the preferred embodiment according to the invention  
         [0012]    [0012]FIG. 5 is the top view of the second rack of the preferred embodiment according to the invention.  
         [0013]    [0013]FIG. 6 is the cross section view of the second rack of the preferred embodiment according to the invention.  
         [0014]    [0014]FIG. 7 is the perspective view of the first rack of the preferred embodiment according to the invention  
         [0015]    [0015]FIG. 8 is the top view of the first rack of the preferred embodiment according to the invention.  
         [0016]    [0016]FIG. 9 is the cross section view of the first rack of the preferred embodiment according to the invention.  
         [0017]    [0017]FIG. 10 is a top view shows the first and second racks of the preferred embodiment according to the invention in scissors arrangement.  
         [0018]    [0018]FIG. 11 is a perspective view shows the first and second racks of the preferred embodiment according to the invention in scissors arrangement.  
         [0019]    [0019]FIG. 12 is a view showing the operation of the preferred embodiment according to the invention.  
         [0020]    [0020]FIG. 13 is another view showing the operation of the preferred embodiment according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    [0021]FIG. 3 is a perspective exploded view of the preferred embodiment of the invention. The keyswitch according to the preferred embodiment of the present invention compresses a keycap  12 , a first rack  13 , a second rack  11 , a plastic body  17 , a flexible circuit board  14 , a resilient body  16  and a base plate  15 . The key cap  12  is of rectangular shape and has two embedding part  121  on one upper lateral side within the inner space thereof, and retaining grooves  123  on another side to clamp the first rack  13  and the second rack  11 .  
         [0022]    The first rack  13  is arranged below the key cap  12  and in scissors arrangement with the second rack  11 . The groove  134  of the first rack  13  engages with the embedding part  121  of the key cap  12 . The forth shaft  115  of the second rack  11  engages with the retaining groove  123  of the key cap  12 .  
         [0023]    The plastic body  17  is arranged below the first rack  13  and the second rack  11 . The plastic body  17  is provided with a through hole for the penetration of the resilient body  16  on locations corresponding to each key cap  12 , first rack  13  and second rack  11 , and two joint holes on both side thereof and corresponding to the first rack  13  and the second rack  11 .  
         [0024]    The resilient body  16  is arranged below the first rack  13  and the second rack  11 , and within the through hole of the plastic body  17 . The resilient body  16  is functioned to support the first rack  13  and the second rack  11 .  
         [0025]    The flexible circuit board  14  is arranged below the plastic body  17  and has a plurality of punched holes on location corresponding to key cap  12 , first rack  13  and second rack  11 . Moreover, the punched holes have been applied with adhesive paste to fix above elements. The base plate  15  is placed below the flexible circuit board  14  to support the elements mounting above.  
         [0026]    As shown in FIGS.  4 - 6 , the second rack  11  has two opposite rack body  113 , wherein one end of each rack body  113  is connected with a connection part  112  and another end of each rack body  113  is connected with an arc-shaped part  114 .  
         [0027]    The second rack  11  is arranged below the key cap  12  and has fourth shaft  115  extending from another end of the rack body  113  and corresponding to the retaining groove  123  of the key cap  12 . A third shaft  117  is arranged on one end of the rack body  113  and corresponding to the join hole of the plastic body  17 . The rack body  113  has an axial hole  118  corresponding to the first rack  13 , the axial hole  118  has an open side.  
         [0028]    As shown in FIGS.  7 - 9 , the first rack  13  has an inverse-U shaped rack body  131 , which has a U-shaped arm portion  133  on inner side thereof. The arm portion  133  has a second shaft  135  on each lateral side, which is corresponding to the axial hole  118  of the second rack  11 . Moreover, the width of the open side is smaller than the maximum width of the hole  118  such that the second shaft  135  can be easily assembled into the hole  118  and is stably retained within the hole  118  after assembling.  
         [0029]    The first rack  13  is arranged below the key cap  12  and has a groove  134  on each end of connection side  139  of the rack body  131 , which is corresponding to the embedding part  121  of the key cap  12 . The rack body  131  has a first shaft  132  on each connection side  139  thereof, which is corresponding to the join hole of the plastic body  17 .  
         [0030]    As shown in FIGS. 10 and 11, the first rack  13  has been provided with arm portion  133  on inner side thereof, therefore the contact area between the first rack  13  and second rack  11  increases. The shaky problem of the key cap  12  can be prevented, and the assembling and disassembling of the key cap  12  is easier.  
         [0031]    By the special design of the second rack  11 , that is the opening on the second rack  11  has suitable orientation such that the second rack  11  can be assembled with most ease. Moreover, the bearing of the second rack  11  is on the inner most side of the arm portion  133  of the first rack  13 . The distortion or breaking of those two racks can be prevented.  
         [0032]    As shown in FIGS. 12 and 13, when the key cap  12  is pressed down, it will be guided by the first rack  13  and the second rack  11  to move downward in vertical direction. The key cap  12  will lead the resilient body  16  to press on the flexible circuit board  14 , thus turning on the keying as shown in FIG. 13. Moreover, if the force acting on the key cap  12  is released, the key cap  12  will be moved upward by the resilient force of the resilient body  16  and guided by the two rack  11  and  13 . The resilient body will be detached from the flexible circuit board  14 , thus turning off the keying, as shown in FIG. 12.  
         [0033]    Moreover, as shown in FIGS. 14 and 15, the shape of the hole  18  is not symmetric such that the shaft  135  has better performance in assembling and retaining in the hole  18  in comparison with the case shown in FIG. 6. As shown in FIG. 15, the hole  18  has a bevel surface near the open side for facilitating automatic production.  
         [0034]    To sum up, the inventive support linkage for keyswitch can solve the assembling and poor strength problems of the conventional keyset of notebook computer; therefore it is of industrial interest.  
         [0035]    Although the present invention has been described with reference to the preferred embodiment thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have suggested in the foregoing description, and other will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.