Patent Publication Number: US-2007120373-A1

Title: Latch mechanism

Description:
CROSS-REFERENCES TO RELATED APPLICATION  
      Related subject matter is disclosed in three co-pending U.S. Patent Applications entitled “Portable computer having improved latch mechanism,” (Ser. No. 11/188,548, filed on Jul. 25, 2005; Ser. No. 11/292,259, filed on Dec. 1, 2005; Ser. No. 11/272,531, filed on Nov. 10, 2005) and assigned to the same assignee with this application. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to latch mechanisms, and more particularly to a reliable latch mechanism.  
      2. Description of Related Art  
      Portable computers, such as laptop computers and notebook computers, have become increasingly popular for general use. Generally, a portable computer includes a cover unit, and a base unit pivotably connected with the cover unit. The cover unit is folded onto the base unit to cover the base unit when the portable computer is not in use. The cover unit includes a latch mechanism provided to lock the cover to the base unit.  
      As disclosed in China Patent No. 01208955.9, a portable computer includes a latch mechanism which acts to lock a cover unit to a base unit when the portable computer is not in use. The latch mechanism includes a hook for engaging in notches defined in the base unit, and a post movably embedded in the base unit for disengaging the hook from the base unit. An end portion of the post is exposed outside the base unit for facilitating pushing the post to disengage the hook from the base unit. However, the end portion of the post is liable to be accidentally touched resulting in an undesired opening of the cover.  
      What is desired, therefore, is a cover which has an improved latch mechanism.  
     SUMMARY OF THE INVENTION  
      In one preferred embodiment, a latch mechanism includes a cover piece, and a latch member. The cover piece includes a base wall, and a flange extending perpendicularly from the base wall. The base wall includes a pair of slots defined therein, and a stop board. The flange includes a cutout defined therein. The latch member is slidably attached to the cover piece and includes a frame slidably received in the cutout of the flange, and a pair of arms having a pair of hooks depending therefrom to movably extend through the slots of the cover piece. The frame includes a rectangular hole defined therein, and a post extending into the hole from an inside wall thereof. A resilient member is fixed around the post and movably engages with the stop board.  
      Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded, isometric view of a cover in accordance with a preferred embodiment of the present invention;  
       FIGS. 2 and 3  are assembled views of  FIG. 1 , but viewed from different aspects; and  
       FIG. 4  is a working schematic side view of the cover of  FIG. 3 , being attached to a base unit. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIGS. 1 and 4 , a latch mechanism in accordance with a preferred embodiment of the present invention is for locking a cover unit  2  to a base unit  3  of a portable electronic device such as a portable computer. The cover unit  2  is pivotably attached to the base unit  3 . The latch mechanism includes a cover piece  20 , and a latch member  40  slidably attached to the cover piece  20 . The cover piece  20  is a lower part of the cover unit  2 . The base unit  3  defines a pair of apertures  32  in a front portion thereof.  
      The cover piece  20  includes a base wall  22 , and a flange  24  formed at a front edge of the base wall  22 . A cutout  242  is defined in the flange  24  by cutting a portion from the flange  24 . Referring also to  FIG. 3 , a pair of slots  222  is defined in the base wall  22 , along the flange  24 . A pair of supporting blocks  224  extends from the base wall  22  between the slots  222 . A pair of first upright catches  226  respectively extends from the base wall  22  adjacent the slots  222  and toward the flange  24 . A pair of spaced guiding bars  228  in alignment extends from the base wall  22 , parallel to the flange  24  and adjacent the cutout  242  of the flange  24 . A guiding tab  232  and a second upright catch  234  perpendicularly extend from the base wall  22  between the cutout  242  of the flange  24  and the guiding bars  228 . The second upright catch  234  extends offset to the first catches  226 . A stop board  236  perpendicularly extends from the base wall  22  and is perpendicular to the guiding tab  232  and the second catch  234 .  
      The latch member  40  is bar-shaped, and includes a rectangular frame  42  at a middle thereof, and a pair of arms  44  extending from two opposite ends of the frame  42  respectively. The frame  42  includes a rectangular through hole  422  defined therein, and a handgrip portion  424  formed at an outer front surface thereof. A post  426  perpendicularly extends in from an inside surface of a right end of the frame  42 , for fixing a resilient member  50  therearound. A pair of hooks  442  depends from the arms  44  respectively, corresponding to the slots  222  of the cover piece  20 .  
      Referring to FIGS.  2  to and  4 , in assembly, the latch member  40  is slidably attached to the cover piece  20 , with the handgrip portion  424  exposed in the cutout  242  of the flange  24 , for facilitating manipulation of the latch member  40 . The resilient member  50  is fixed around the post  426  of the latch member  40 . A free end of the resilient member  50  presses against the stop board  236 . The guiding tab  232  and the second catch  234  extend through the through hole  422  of the frame  42 . The guiding tab  232  slidably abuts against an outer sidewall of the frame  42 , and the second catch  234  slidably engages with an inside wall of the frame  42  of the latch member  40 . The guiding bars  228  slidably abut against a rear outer surface of the frame  42 . The arms  44  of the latch member  40  are slidably placed on the supporting blocks  224  of the cover piece  20 . The hooks  442  of the latch member  40  extend through the slots  222  of the base wall  22  of the cover piece  20 . The first catches  226  of the cover piece  20  slidably engage with the arms  44  of the latch member  40 . The second catch  234  slidably engages with an outer rear surface of the frame  42 . The first catches  226  and the second catch  234  also slidably engage with top portions of the arms  44  and a top portion of the frame  42 , preventing an upward movement of the latch member  40 .  
      The cover piece  20  is then assembled with the cover unit  2 . The cover unit  2  is pivotably attached to the base unit  3 , and the cover unit  2  is folded to cover the base unit  3 , with the hooks  442  engaging in the apertures  32  and latching to the base unit  2 .  
      To open the cover unit  1  of the electronic device, the handgrip portion  424  of the latch member  40  is urged to the left compressing the resilient member  50  and disengaging the hooks  442  from the apertures  32  of the base unit  3 . The cover unit  1  is ready to be opened. When the handgrip portion  424  is released, the resilient member  50  rebounds thus urging the latch member  40  back to its original position.  
      Numbers of the hooks  442  of the latch member  40  and the slots  222  of the cover piece  20  can be varied according to different situations. The latch member  40  can be slidably attached to any possible sidewalls of the cover unit  2  and base unit  3 , with the handgrip portion  424  thereof exposed to be easily operated.  
      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 a preferred or exemplary embodiment.