Abstract:
A latch mechanism for locking a cover unit to a base unit which comprises a bottom panel and a cover panel fixed to the bottom panel and defining a through hole, includes a latch member configured for being slidably installed to the bottom panel and between the bottom panel and the cover panel, a hook protruding from the cover unit, a button movably fixed to the bottom panel, and a resilient member connected to the button configured for restoring the button. The latch member includes a latch portion and a sliding slot. The hook extends through the through hole of the cover panel to engage with the latch portion of the latch member. The button includes a driving portion sliding in the sliding slot of the latch member for driving the latch member to slide toward the button to disengage from the hook.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to latch mechanisms, and more particularly to a latch mechanism for a portable computer. 
         [0003]    2. Description of Related Art 
         [0004]    Typically, an electronic device, such as a portable computer, includes a cover unit and a base unit pivotably connected to the cover unit, and a latch mechanism is provided to lock the cover unit to the base unit. 
         [0005]    As disclosed in U.S. Pat. No. 6,115,239, a latch mechanism for locking a cover unit to a base unit, includes a latch frame movably installed inside the cover unit, a plurality of latches are formed on the latch frame at predetermined intervals and one end portion of each latch protrudes from a front surface of the cover unit, and a slide knob is operatively connected to the latch frame for concurrently operating the latches. The latches are inserted into and locked by latch grooves formed at positions corresponding to the latches on an upper surface of the base unit. The latches are urged against the base unit by elastic forces applied by double springs mounted to two ends of the latch frame. However, to open the cover unit, the slide knob is slid to overcome the elastic forces of the springs to move the latch mechanism for disengaging from the base unit. The slide force depends on friction between the slide knob and fingers of an operator. It is laborious for an operator to provide enough force to move a slide knob. 
         [0006]    What is needed, therefore, is a laborsaving latch mechanism. 
       SUMMARY 
       [0007]    In one embodiment, a latch mechanism for locking a cover unit to a base unit which comprises a bottom panel and a cover panel fixed to the bottom panel and defining a through hole therein, includes a latch member configured for being slidably installed to the bottom panel and between the bottom panel and the cover panel, a hook protruding from the cover unit, a button movably fixed to the bottom panel, and a resilient member connected to the button configured for restoring the button. The latch member includes a latch portion and a sliding slot. The hook extends through the through hole of the cover panel to engage with the latch portion of the latch member. The button includes a driving portion sliding in the sliding slot of the latch member for driving the latch member to slide toward the button to disengage from the hook. 
         [0008]    Other advantages and novel features of the present invention will become more apparent from the following detailed description of an embodiment when taken in conjunction with the accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is an exploded, isometric view of a latch mechanism with a cover unit and a base unit in accordance with an embodiment of the present invention, the base unit including a bottom panel and a cover panel; 
           [0010]      FIG. 2  shows another aspect view of the cover unit of  FIG. 1 ; 
           [0011]      FIG. 3  is an enlarged view of the latch mechanism with the bottom panel of  FIG. 1 ; 
           [0012]      FIG. 4  is an assembled view of the latch mechanism together with the bottom panel of  FIG. 1 ; and 
           [0013]      FIGS. 5 and 6  are cross-sectional, partial views of the latch mechanism, showing two using states respectively. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIGS. 1 and 2 , a latch mechanism in accordance with an embodiment of the present invention is provided, for locking a cover unit  10  to a base unit  20  of an electronic device, such as a portable computer. The latch mechanism includes a button  30 , two latch members  40 , a resilient member  50 , a mounting member  60 , and two supporting members  70 . In this embodiment, the resilient member  50  is a coil spring. 
         [0015]    The cover unit  10  includes two hooks  12  arranged thereon at one side surface thereof. Each hook  12  includes a tapered leading portion  122  formed at a free end thereof, and a locking slot  124  defined therein in the vicinity of the leading portion  122 . 
         [0016]    Referring also to  FIG. 3 , the base unit  20  includes a bottom panel  22 , and a cover panel  24  covered on the bottom panel  22 . The bottom panel  22  has a flange  221  extending up from one side thereof. A receiving slot  224  is defined in a middle portion of the flange  221 . The bottom panel  22  forms two columns  222  adjacent to the receiving slot  224 , two locating rods  225 , and two mounting rods  226  adjacent to the locating rods  225  respectively. A rib (not labeled) is formed on the bottom panel  22  connected to the columns  222 . A mounting hole  223  is defined in each column  222 . The locating rods  225  and the mounting rods  226  extend from the bottom panel  22  away from the receiving slot  224 . A mounting hole  227  is defined in each mounting rod  226 . The cover panel  24  defines two through holes  242 . 
         [0017]    The button  30  includes an operating portion  31 , a columnar portion  32  extending from one side of the operating portion  31 , and two wings  34  extending from opposite sides of the columnar portion  32  respectively. Each wing  34  includes a driving portion  35  protruding up from a distal end thereof. Each driving portion  35  has a generally rhombic-shaped section. A receiving hole (not shown) is defined in the columnar portion  32  along a longitudinal axis thereof. 
         [0018]    Each latch member  40  is elongate, and includes a locking end and a driven end  41  at opposite ends thereof respectively. A first restricting slot  43  and a second restricting slot  45  are defined in the latch member  40  in the vicinity of the driven end  41 , and the locking end respectively. The first and second restricting slots  43 ,  45  each include a large end and a small end, respectively. An inclined sliding slot  42  is defined in the driven end  41 . A U-shaped cutout is defined in the locking end, an arc-shaped latch portion  46  is formed at a bottom wall of the cutout. 
         [0019]    The mounting member  60  includes a bottom wall  61 , a trapezium-shaped first sidewall  62  and a trapezium-shaped second sidewall  63  extending up from a back and a front sides of the bottom wall  61  respectively. Two limiting poles  612 ,  614  protrude up from opposite ends of the bottom wall  61 . A T-shaped limiting block  614  is formed on a top portion of each limiting pole  612 . Two through holes  616  are defined in the bottom wall  61  in the vicinity of the two limiting poles  612  respectively and adjacent to the first sidewall  62 . Two limiting plates  618  extend up from the bottom wall  61  in the vicinity of the first sidewall  62 . A rod  622  protrudes from the first sidewall  62  toward the second sidewall  63 . A through slot  632  is defined in a middle portion of the second sidewall  63 . 
         [0020]    Each supporting member  70  includes a base plate  71 , a columnar supporting portion  72  and a pillar  73  extending up from the base plate  71 . The supporting portion  72  defines a locking hole  722  therein along its longitudinal axis. A slot  726  is defined in a circumference of the supporting portion  72  perpendicular to the axis of the supporting portion  72  and communicating with the locking hole  722 . A T-shaped limiting block  732  is formed on a top portion of the pillar  73  along an axis. A mounting hole  78  and a locating hole  79  are defined in the base plate  71 . 
         [0021]    Referring also to  FIG. 4 , in assembly, two screws extend through the through holes  616  of the mounting member  60  to engage in the mounting holes  223  of the columns  222  of the bottom panel  22 , for fixing the mounting member  60  to the bottom panel  22 . One end of the resilient member  50  is received in the receiving hole of the columnar portion  33  of the button  30 . The button  30  is placed between the first and second sidewalls  62 ,  63  of the mounting member  60 . The operating portion  31  of the button  30  extends through the through slot  632  of the second sidewall  63  of the mounting member  60  to be retained in the receiving slot  224  of the flange  221  of the bottom panel  22  of the base unit  20 . The other end of the resilient member  50  is fitted about the rod  622  of the first sidewall  62  of the mounting member  60 . 
         [0022]    Each supporting member  70  is fixed to the bottom panel  22  via the corresponding locating rod  225  of the bottom panel engaging in the locating hole  79  of the supporting member  70  and a screw extending through the mounting hole  78  of the supporting member  70  to engage in the mounting hole  227  of the corresponding mounting rod  226  of the bottom panel  22 . The latch members  40  are located at the bottom panel  22  and at opposite sides of the receiving slot  224  respectively, each being fixed to a corresponding limiting pole  612  and the pillar  73  of a corresponding supporting member  70 . The T-shaped limiting block  614  of the corresponding limiting pole  612  and the limiting block  732  of the pillar  73  are inserted through the large ends of the first and second restricting slots  43 ,  45  of the latch member  40 . Each latch member  40  is moved away from the button  30 , with the limiting block  614  of the corresponding mounting member  60  and the limiting block  732  of the corresponding supporting member  70  being accommodated in the small ends of the first and second restricting slots  43 ,  45  respectively. The driving portions  35  of the button  30  are engaged in the sliding slots  42  of the corresponding latch members  40 . The locking ends of the latch members  40  are engaged in the slots  726  of the corresponding supporting members  70 . 
         [0023]    Referring also to  FIGS. 5 and 6 , the cover panel  24  is fixed to the bottom panel  22 , thereby the base unit  20  is fully assembled. The cover unit  10  is rotatably attached to the base unit  20 . The cover unit  10  is rotated to cover the base unit  20  when the electronic device is not in use. The leading portions  122  of the hooks  12  of the cover unit  10  extend through the corresponding through holes  242  of the cover panel  24  of the base unit  20  to abut against the latch portions  46  of the corresponding latch members  40 . The cover unit  10  is further rotated, the leading portions  122  of the hooks  12  drive the latch members  40  to slide toward the button  30 . The button  30  is driven to slide backward against the resilient member  50  and the driving portions  35  thereof slide along the sliding slots  42  of the latch members  40  respectively. After the leading portions  122  of the hooks  12  entirely extend through the latch members  40  respectively, the resilient member  50  rebounds to drive the button  30  to move forward. The driving portions  35  slide along the sliding slots  42  of the corresponding latch members  40  to drive the latch members  40  to move away from the button  30  until the latch portions  46  of the latch members  40  are engaged in the locking slots  124  of the hooks  12  respectively. Thus, the cover unit  10  is locked to the base unit  20 . 
         [0024]    To unlock the cover unit  10  from the base unit  20 , the operating portion  31  of the button  30  is pressed to drive the button  30  move backward and compress the resilient member  50 . The driving portions  35  of the button  30  slide in the sliding slots  42  of the latch members  40  respectively to drive the latch members  40  to move toward the button  30 . When the latch portions  46  of the latch members  40  are disengaged from the locking slots  124  of the hooks  12 , the cover unit  10  is released from the base unit  20 . 
         [0025]    Each limiting plate  618  of the mounting member  60  is used for blocking one side of a corresponding latch member  40  to restrict the latch member  40 . 
         [0026]    As a second embodiment of the present invention, the driving portions  35  of the button  30  can have a columnar shape or other shapes easily slidable in the sliding slots  42 . Furthermore, The first and second sidewalls  62 ,  63 , the two limiting poles  612 , and the two limiting plates  618  can directly protrude from the bottom panel  22 . 
         [0027]    It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.