Abstract:
A power button assembly includes a printed circuit board having a switch, a support plate engaging with the printed circuit board, and a push button to activate the switch. The support plate includes abutting portions to elastically abut against the push button, and one of the support plate and the push button includes hook portions, and the other includes latching portions engaging with the hook portions.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to a power button assembly and an electronic device using the power button assembly. 
         [0003]    2. Description of the Related Art 
         [0004]    An electronic device is generally provided with a power button assembly to turn a power supply on and off. A commonly used power button assembly includes a plurality of components such as a printed circuit board (PCB), a support plate, a push button, and an elastic member positioned between the push button and the PCB to generate an elastic force to abut/push against the push button. The push button may be received in an assembly hole defined in a housing of the electronic device. The PCB may engage the support plate. During assembly of the power button assembly to the housing of the electronic device, the push button is received in the assembly hole, the elastic member is positioned on one side of the push button adjacent to the PCB, and the support plate is connected to the housing to bias the elastic member to exert a set amount of elastic force acting on the push button. During assembly, the elastic member and the push button require manual positioning which are difficult to accurately control. Over time, the elastic member may loosen and no longer supply a sufficient stable elastic force to push or abut against the push button, such that the operation of the power button assembly becomes frustrated. 
         [0005]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views. 
           [0007]      FIG. 1  is a partial, isometric view of an embodiment of an electronic device, the electronic device including an embodiment of a power button assembly. 
           [0008]      FIG. 2  is similar to  FIG. 1 , but is viewed from another perspective. 
           [0009]      FIG. 3  is an exploded, isometric view of the power button assembly. 
           [0010]      FIG. 4  is similar to  FIG. 3 , but is viewed from another perspective. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Referring to  FIGS. 1 and 2 , an embodiment of an electronic device  100  includes a housing  20  and a power button assembly  30 . The housing  20  defines an assembly hole  21  therein. The electronic device  100  may be a notebook, a desktop computer, a liquid crystal display or other electronic device capable of employing the power button assembly  30 . 
         [0012]    Referring also to  FIGS. 3 and 4 , the power button assembly  30  includes a PCB  31 , a support plate  32 , and a push button  33 . 
         [0013]    The PCB  31  includes a mainboard  311  and a switch (not labeled). The mainboard  311  includes a first surface  3112  and a second surface  3113  opposite to the first surface  3112 . The switch includes a dome  312  fixed on the second surface  3113 , a first electric terminal  314 , and a second electric terminal  315  adjacent to the first electric terminal  314 . The first and second electric terminals  314 ,  315  are fixed on the first surface  3112  of the mainboard  311 . The dome  312  is adjacent to the ends of the first and second electric terminals  314 ,  315 , such that when the dome  312  is elastically depressed, the first and second electric terminals  314 ,  315  electrically connect to each other, turning the power supply on and off. 
         [0014]    The support plate  32  is a substantially annular metal sheet. The support plate  32  defines a depression  321  in the central region thereof to receive the push button  33 . The depression  321  has a bottom wall  323  on which the mainboard  311  of the PCB  31  is fixed. The support plate  32  may be fixed to the housing  20  by double-sided adhesive or rivet. 
         [0015]    The support plate  32  includes a plurality of abutting portions  324  and a plurality of hook portions  325  integrally formed on the bottom wall  323  thereof. 
         [0016]    Each abutting portion  324  includes an elastic supporting arm  3241  and an abutting arm  3242  formed on a distal end of the elastic supporting arm  3241 . The hook portions  325  engage with the push button  33 , and the abutting arm  3242  elastically contacts the push button  33 , such that the abutting portion  324  generates stable elastic force to abut/push against the push button  33 . In the illustrated embodiment, the power button assembly  30  includes two pairs of hook portions  325  and three abutting portions  324 . The two pairs of hook portions  325  are on opposite sides along a central axis of the bottom wall  323 . The abutting portions  324  are formed on the inner circumference of the bottom wall  323  at regular intervals along the circumference. The abutting portions  324  and the hook portions  325  may be formed by punching or stamping, simplifying manufacture. 
         [0017]    The push button  33  includes a cap  331  and a connecting portion  332  extending radially from the bottom edge of the cap  331 . A contact  3313  is formed on the cap  331 , and is pressed towards the dome  312  to activate the switch. Two latching portions  334  are integrally formed on the outer circumferential edge of the connecting portion  332 , and the latching portions  334  are opposite to each other. Each latching portion  334  includes a stepped surface  3341  and a locking portion  3342  extending outward from the edge of the stepped surface  3341 . 
         [0018]    During the assembly of the power button assembly  30 , a pair of hook portions  325  engage the stepped surface  3341  of the latching portion  334 , thus connecting the push button  33  to the support plate  32 , with the abutting portions  324  abutting the push button  33 . The locking portion  3342  is received between two hook portions  325  to restrict the rotation of the push button  33 , allowing more accurate positioning of the push button  33 . 
         [0019]    After the power button assembly  30  is assembled, the push button  33  is received in the assembly hole  21  of the housing  20 , and the support plate  32  is fixed to the housing  20  by double-sided adhesive or rivet, so that the power button assembly  30  can be easily connected to the housing  20 . It is unnecessary to provide dedicated hardware and manpower to assemble the power button assembly  30  in the assembly line of the electronic device  100 , because the power button assembly  30  can be assembled elsewhere in advance. 
         [0020]    In operation, as the push button  33  is depressed towards the dome  312 , the contact  3313  elastically deforms the dome  312  which electrically connects the first and second electric terminals  314 ,  315  to turn the power supply on and off, and the abutting portions  324  are being pushed against, and thereby accumulate an elastic force. When the push button  33  is released, the elastic force is released, and the push button  33  returns to its original position, whereby the contact  3313  detaches from the dome  312  to turn the power supply on or off. 
         [0021]    In alternative embodiments, the hook portions  325  are formed on the push button  33 , and the latching portion  334  are formed on the support plate  32  to engage with the hook portions  325 . 
         [0022]    It is believed that the present embodiments and their 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 embodiments or sacrificing all of its material advantages.