Abstract:
A latch mechanism is applied in a notebook PC or similar apparatus with a base and foldable cover. The latch mechanism includes a first fastener installed in a foldable cover and a second fastener installed in a base. A bump is formed in the coupling surface of the first fastener and a corresponding recess is formed in the coupling surface of the second fastener. When coupling, the bump is wedged in the corresponding recess.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is based on, and claims priority from, Taiwan Application Serial Number 94102531, filed Jan. 27, 2005, the disclosure of which is hereby incorporated by reference herein in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a latch mechanism, and more particularly to a portable computer latch mechanism.  
       BACKGROUND OF THE INVENTION  
       [0003]     A portable computer includes a base and a foldable cover that connects with the base through a shaft mechanism. A screen is embedded in the foldable cover. While in use, the foldable cover is lifted to separate from the base for exposing the embedded screen. While in movement, the foldable cover is closed to the base. A latch mechanism is used to fix the foldable cover and the base while closing to prevent the screen from damage.  
         [0004]     Typically, a latch mechanism includes a hook and a ring respectively installed in the base and the foldable cover. A spring is connected with the hook to modify the hook position. When the base and the foldable cover are folded, the hook grapples with the ring to fix the base and the cover. When the foldable cover is lifted, the hook is moved from its original position by deforming the spring to separate the cover and the base. However, when the cover and base are separated, the hook usually protrudes from the surface. A careless user often breaks the protruding hook. Moreover, a spring is used to define the hook orientation. Once the spring has been permanently deformed because of fatigue, the spring may not bring the hook to the latch position again, which affects the fixed stability. Further, when a computer is used as a writing tablet, the protruding hook impedes the user from writing on the screen.  
         [0005]     For resolving the foregoing problems, a magnetic latch has been developed. However, the magnetic field must be limited within a special range to avoid damaging the electrical device inside the base. In other words, the clasping strength of the magnetic latch has an inherent limitation.  
       SUMMARY OF THE INVENTION  
       [0006]     Therefore, the object of the present invention is to provide a latch mechanism used in the portable computer to improve the fixing efficiency.  
         [0007]     Another object of the present invention is to provide an interference type latch mechanism for rigidly fixing the cover and the base.  
         [0008]     Accordingly, the present invention provides an interference type latch mechanism. This latch mechanism can be used in a portable computer or the like apparatus with a base and foldable cover.  
         [0009]     This interference type latch mechanism includes a first fastener and a second fastener. The first fastener is installed in the cover. The second fastener is installed in the base. In a preferred embodiment, a bump is formed in the coupling surface of the first fastener. A corresponding recess is formed in the coupling surface of the second fastener. In the other embodiment, a bump is formed in the coupling surface of the second fastener. A corresponding recess is formed in the coupling surface of the first fastener.  
         [0010]     When the cover is closed to the base, the first fastener coupling with the second fastener. The bump is wedged into the recess. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated and better understood by referencing the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0012]      FIG. 1  illustrates a schematic diagram of a latch mechanism installed in a portable computer according to the preferred embodiment of the present invention;  
         [0013]      FIG. 2  illustrates an enlarged diagram of the region  150  in  FIG. 1 ;  
         [0014]      FIG. 3  illustrates a schematic diagram of using the latch mechanism to fix the cover and the base according to the preferred embodiment of the present invention; and  
         [0015]      FIG. 4  illustrates an enlarged diagram of the region  160  in  FIG. 3 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     The latch mechanism of the present invention may improve the fixing stability when the cover is closed.  FIG. 1  illustrates a schematic diagram of a latch mechanism installed in a portable computer according to the preferred embodiment of the present invention. This portable computer includes a cover  110  and a base  120 . A latch mechanism of the present inveniotn is installed in the portable computer. This latch mechanism includes a first fastener  130  and a second fastener  140 . The first fastener  130  is installed in the rim of the cover  110 . The second fastener  140  is installed in the rim of the base  120 . in a preferred embodiment, the first fastener  130  and the second fastener  140  are made by a metal material.  
         [0017]     The first fastener  130  is composed of three parts including a holding part  130   a,  an extending part  132  and a coupling part  130   b.  The holding part is joined to the rim of the cover  110  and through the extending part  132  to connect with the coupling part  130   b.  The extending part  132  extends from the cover  110  so as to make the coupling part  130   b  located lower than the holding part  130   a.  In other words, the first fastener  130  has a zigzag shape that is from the holding part  130   a  through the extending part  132  bent smoothly down to the coupling part  130   b.  The second fastener  140  has a strip shape and is joined to the rim of the base  120 .  
         [0018]     In othe embodiment, the first fastener can be installed in the rim of the base  120 . The second fastener can be installed in the rim of the cover  110 . In this embodiment, the first fastener  130  has a zigzag shape that is from the holding part  130   a  through the extending part  132  bent smoothly up to the coupling part  130   b.    
         [0019]      FIG. 2  illustrates an enlarged diagram of the region  150  in  FIG. 1 . The coupling part  130   b  protrudes from the cover  110 . The protruding coupling part  130   b  may couple with the second fastener  140  when the cover  110  is closed against the base  120 . Moreover, a bump  135  is formed in the coupling surface of the first fastener  130 . A corresponding recess (not shown in this figure) is formed in the coupling surface of the second fastener  140 . When the cover  110  is closed, the bump  135  is wedged into the corresponding recess to improve the clasping strength between the cover  110  and the base  120 .  
         [0020]     In another embodiment, the bump  135  can also be formed in the coupling surface of the second fastener  140 . A corresponding recess (not shown in this figure) is formed in the coupling surface of the first fastener  130 . The height of the bump  130 , the depth of the recess and the area of the coupling surface are related to the clasping strength. In other words, when requiring a higher clasping strength, a higher bump and a larger coupling surface are required. According to the preferred embodiment, the bump has a hemispherical shape.  
         [0021]      FIG. 3  illustrates a schematic diagram of using the latch mechanism to fix the cover and the base according to the preferred embodiment of the present invention. When the cover  110  is closed, the coupling surfaces of the first fastener  130  and the second fastener  140  are connected to each other. A tight clasp can be reached by the bump wedging into the corresponding recess. It is noticed that the positions of the first fastener  130  and the second fastener  140  respectively located in the cover  110  and the base  120  can be changed as long as the two fasteners  130  and  140  can be coupled together when the cover  110  is closed. In other words, the user can freely modify the latch mechanism position in the portable computer based on the usage condition. For example, the latch mechanisms can be designed to locate in different positions for different persons.  
         [0022]      FIG. 4  illustrates an enlarged diagram of the region  160  in  FIG. 3 . The first fastener  130  and the second fastener  140  are coupled together. According to the present invention, when a user wants to lift the cover  110 , he can apply force in different directions, indicated by the arrow  162   a  and the arrow  162   b,  to the first fastener  130  and the second fastener  140  respectively.  
         [0023]     Accordingly, the first fastener and the second fastener of the present invention are exposed from the shell. Therefore, the two fasteners can prevent the damage of directly hitting the shell. Moreover, when changing the position of the two fasteners, it is not necessary to open the shell, which can avoid breaking the device inside the shell. Moreover, no spring is used in the latch mechanism of the present invention. Therefore, the present invention may eliminate the situation of the clasping strength being reduced due to fatigue.  
         [0024]     As is understood by a person skilled in the art, the foregoing descriptions of the preferred embodiment of the present invention are an illustration of the present invention rather than a limitation thereof. Various modifications and similar arrangements are included within the spirit and scope of the appended claims. The scope of the claims should be accorded to the broadest interpretation so as to encompass all such modifications and similar structures. While a preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.