Abstract:
A latch mechanism is provided for locking a cover unit to a base unit. The latch mechanism includes a locking member slidably installed in the cover unit, a button movably attached to the cover unit, and a pivot member pivotably connected to the cover unit. The locking member includes a hook for engaging with the base unit, and an engaging portion formed thereon. The button forms a pushing portion. The pivot member is capable of being driven by the pushing portion of the button to rotate and in turn to slide the locking member for disengaging the hook from the base unit.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a latch mechanism, and more particularly to a latch mechanism for a portable computer. 
     2. Description of related art 
     Typically, an electronic device, such as a portable computer, includes a cover unit and a base unit pivotally connected with the cover unit, and a latch mechanism is provided to lock the cover unit to the base unit. 
     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 on 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. 
     What is needed, therefore, is a laborsaving latch mechanism. 
     SUMMARY OF THE INVENTION 
     A latch mechanism is provided for locking a cover unit to a base unit. The latch mechanism includes a locking member slidably installed in the cover unit, a button movably attached to the cover unit, and a pivot member pivotably connected to the cover unit. The locking member includes a hook for engaging with the base unit, and an engaging portion formed thereon. The button forms a pushing portion. The pivot member is capable of being driven by the pushing portion of the button to rotate and in turn to slide the locking member for disengaging the hook from the base unit. 
     Other advantages and novel features will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded, isometric view of a latch mechanism with a cover unit in accordance with a preferred embodiment of the present invention, the cover unit including a first panel and a second panel; 
         FIG. 2  is an enlarged view of a circled portion  11  of  FIG. 1 ; 
         FIG. 3  is an enlarged, assembled view of  FIG. 1  with a portion of the second panel of the cover unit being cut out; 
         FIG. 4  is similar to  FIG. 3 , but showing another state of the latch mechanism; and 
         FIG. 5  is a schematic, assembled and part-sectioned view of  FIG. 1  together with a base unit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 and 5 , a latch mechanism is provided in accordance with a preferred embodiment of the present invention, 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 , a locking member  40 , a pivot member  50 , and two resilient members  60 . In this embodiment, the resilient members  60  are springs. The base unit  20  defines a pair of latching slots  22 . 
     Referring also to  FIG. 2 , the cover unit  10  includes a first panel  12 , and a second panel  14  having a cutout  141  defined therein. A recess  121  is defined inward in a middle of a front edge of the first panel  12 . Two pairs of retainers  126  are formed on an inside surface of the first panel  12 . Each one of each pair of retainers  126  has a hook facing to the hook of the other one. Two tabs  125  are formed on the inside surface of the first panel  12  between the retainers  126 . Orientation of the tabs  125  are perpendicular to that of the retainers  126 . Two columnar restricting portions  124  extend from the inside surface of the first panel  12  between the tabs  125 . Two holders  123  are formed on the inside surface of the first panel  12  between the restricting portions  124  adjacent to the front edge of the first panel  12 . A protrusion  127  protrudes from the inside surface of the first panel  12  beside each holder  123  away from the front edge of the first panel  12 . A post  122  is formed perpendicularly on the inside surface of the first panel  12  between the holders  123  adjacent to the recess  121 . The tabs  125  and the restricting portions  124  are arranged in a line and parallel to the front edge of the first panel  12 . A slot  128  is defined in the first panel  12  beside each pair of the retainers  126 . 
     The button  30  includes a body having a U-shaped cutout defined in a middle portion thereof, a press portion  32  protruding from an edge of the body, two sliding portions  34  formed from two ends of the body, and a pushing portion  36  extending into the cutout from the body. 
     The locking member  40  includes two hooks  41  depending from two ends thereof respectively, corresponding to the slots  128  of the first panel  12 , two receiving slots  47  defined therein adjacent to the ends of the locking member  40  respectively, two elongated through holes  46  defined therein between the receiving slots  47  corresponding to the restricting portions  124  of the first panel  12 , and an arched portion  42  formed from a middle section thereof. Each hook  41  has a hooking portion  412  at an end thereof. The two hooking portions  412  have the same orientation. A pole  48  extends horizontally from the locking member  40  into each receiving slot  47 . A groove  43  is defined in the locking member  40  under the arched portion  42 . An engaging portion  44  is formed on the locking member  40  bounding a left end of the groove  43 . 
     The pivot member  50  is a generally triangle-shaped plate. A pivoting hole  52  is defined in a corner of the pivot member  50 . The pivot member  50  forms a driving portion  54  and a driven portion  56  at two lateral surfaces sandwiching the corner. 
     Referring also to  FIG. 3 , in assembly, the button  30  is retained between the holders  123  in a left-and-right direction, and the sliding portions  34  of the button  30  are located under hooks of the holders  123 . The press portion  32  of the button  30  is exposed from the recess  121  of the first panel  12 . The protrusions  127  act to prevent further movement of the button  30 . The pivot member  50  is pivotably connected to the first panel  12  via the post  122  of the first panel  12  pivotably received in the pivoting hole  52  of the pivot member  50 . The resilient members  60  are placed around the poles  48  of the locking member  40  respectively. The locking member  40  is retained between the retainers  126  in a back-and-forth direction, and the hooks  41  of the locking member  40  extend through the slots  128  of the first panel  12  respectively. The tabs  125  of the first panel  12  extend into the receiving slots  47  of the locking member  40  respectively, thus one end of each resilient member  60  engages with the corresponding tab  125 . The restricting portions  124  of the first panel  12  extend into the through holes  46  respectively for restricting the locking member  40  moving in the back-and-forth direction while guiding the locking member  40  moving in the left-and-right direction. A part of the pivot member  50  is under the arched portion  42  of the locking member  40 . 
     Referring also to  FIGS. 4 and 5 , the second panel  14  holds a liquid crystal display (not shown) therein, and the first panel  12  is fixed to the second panel  14  to cover one side of the liquid crystal display, thereby the cover unit  10  is fully assembled. The cutout  141  of the second panel  14  is coupled with the recess  121  of the first panel  12 . 
     The cover unit  10  is pivotably attached to the base unit  20 . The cover unit  10  is pivoted to cover the base unit  20  when the electronic device is not in use. When bottom surfaces of the hooking portions  412  of the hooks  41  abut against portions adjoining the latching slots  22  of the base unit  20  respectively, the cover unit  10  is pressed downward, the portions of the base unit  20  drive the locking member  40  to slide leftward by urging against the hooks  412  of the locking member  40 . The resilient members  60  are compressed by the tabs  125  of the first panel  12  of the cover  10  respectively. When the hooking portions  412  of the hooks  41  entirely enter the latching slots  22  of the base unit  20  respectively, the resilient members  60  rebound to push the locking member  40  to slide rightward, the hooking portions  412  of the hooks  41  engage with the portions of the base unit  20  adjoining the latching slots  22 . Thus, the cover unit  10  is locked to the base unit  20 . 
     Referring further to  FIG. 4 , to unlock the cover unit  10  from the base unit  20 , the press portion  32  of the button  30  is pressed to move the button  30  backward along the holders  123  of the first panel  12 . The pushing portion  36  of the button  30  pushes the driven portion  56  of the pivot member  50  inward to pivot the pivot member  50 , thus the driving portion  54  of the pivot member  50  urges against the engaging portion  44  of the locking member  40 , the locking member  40  is therefore pushed to slide leftward, and compresses the resilient member  60 . When the hooking portions  412  of the hooks  41  move to align with the corresponding latching slots  22  and disengage from the portions adjoining the latching slots  22  respectively, the cover unit  10  is ready to be pivoted open. 
     It is believed that the present embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the example hereinbefore described merely being preferred or exemplary embodiment of the invention.