Abstract:
A power supply adapter includes a casing defining at least one inserting groove therein, at least one resilient piece disposed in the casing and having a locating portion and a resisting portion extended gradually upward from the locating portion, and a plug module rotatablely disposed in the casing. The plug module has at least one retaining block disposed in the inserting groove of the casing and capable of rotating around the resisting portion of the resilient piece. A connecting terminal runs through the retaining block to form an inserting portion and a projecting portion at opposite sides of the retaining block. The projecting portion is capable of compressing the resisting portion when the inserting portion is raised erectly to be exposed externally from the inserting groove.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to a power supply adapter, and more particularly to a power supply adapter with a foldable plug module. 
   2. The Related Art 
   A power supply adapter is widely used in many electronic devices for converting alternating current (AC) power into direct current (DC) power so as to supply the required DC power to operate or charge the electronic devices. 
   A conventional power supply adapter is disclosed in U.S. Pat. No. 6,548,755. According to disclosure of the patent, the power supply adapter includes a first casing, a second casing, a rotatable cylinder and a projecting plug. The first casing defines a cavity at a front end thereof. Two vertical plates are mounted on the second casing for supporting the rotatable cylinder. The projecting plug is formed on a front end of the rotatable cylinder and extends from a cavity space defined by the front end of the first casing and the second casing. By rotating the rotatable cylinder, the angle of the projecting plug is changed. 
   However, the power supply adapter of this type fails to locate the projecting plug stably in place when the projecting plug is raised to mate with other electronic apparatus, thus leading to unstable connection between the projecting plug and the electronic apparatus. Then, an improved power supply adapter capable of locating the projecting plug stably is desired. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a power supply adapter capable of firming a plug module thereof. The power supply adapter comprises a casing defining at least one inserting groove therein, at least one resilient piece disposed in the casing and having a locating portion and a resisting portion extended gradually upward from the locating portion, and a plug module rotatablely disposed in the casing. The plug module has at least one retaining block disposed in the inserting groove of the casing and capable of rotating around the resisting portion of the resilient piece. A connecting terminal runs through the retaining block to form an inserting portion and a projecting portion at opposite sides of the retaining block. The projecting portion is capable of compressing the resisting portion when the inserting portion is raised erectly to be exposed externally from the inserting groove. 
   As described above, the power supply adapter utilizes the resilient piece to fix the inserting portion of the plug module because the resisting portion exerts elastic force upon the projecting portion when the projecting portion compresses the resisting portion, so as that the inserting portion is capable of stably connecting with other electronic apparatus. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which: 
       FIG. 1  is an exploded view of a power supply adapter according to an embodiment of the present invention; 
       FIG. 2  is a perspective view of an upper casing of the power supply adapter of  FIG. 1  while viewed from inside of the upper casing; 
       FIG. 3  is an assembly view of the power supply adapter without the upper casing; 
       FIG. 4  is a perspective view of the power supply adapter of  FIG. 1 ; 
       FIG. 5  is a cross-sectional view of the power supply adapter of which plug module is raised; 
       FIG. 6  is a cross-sectional view of the power supply adapter of which the plug module is folded to a stowed position; and 
       FIG. 7  is a perspective view of a power supply adapter according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , a power supply adapter  1  in accordance with the present invention includes an upper casing  10 , a bearing frame  20 , a locating screw  30 , a plug module  40 , a pair of resilient pieces  50 , a printed circuit board (PCB)  60 , a pair of conductive members  70  and a lower casing  80  which can couple with the upper casing  10  to form a receiving space  13  therebetween for receiving the bearing frame  20 , the locating screw  30 , the plug module  40 , the two resilient pieces  50 , the PCB  60  and the two conductive members  70  therein. 
   With reference to  FIG. 1  and  FIG. 2 , the upper casing  10  has a top board  11  and two sideboards  12  extended downward from two lateral sides of the top board  11  respectively. Partial material of the front portion of the top board  11  is removed so as to form a bottom portion  141 , a rear portion  142  and two sidewalls (not labeled). The bottom portion  141 , the rear portion  142  and the two sidewalls define in conjunction a receiving recess  14 . Two separate inserting grooves  15  are defined on the top board  11  and communicate with inside of the upper casing  10 . The inserting grooves  15  are arranged in the rear portion  142  respectively to communicate with the receiving recess  14 . A first hollow locating pillar  16  is protruded upon an opposite side of the bottom portion  141  at a substantially middle portion thereof. Two pairs of locating posts  17  are also extended from the side, upon which the first locating pillar  16  is protruded, of the bottom portion  141 . One pair of the locating posts  17  is disposed at opposite sides of the first locating pillar  16  and the other pair of the locating posts  17  is adjacent to the rear portion of the opposite side of the bottom portion  141 . A reverse side of the top board  11  defines two pairs of first vertical plates  18  which protrude downward. Every one pair of the first vertical plates  18  is disposed at opposite sides of the inserting groove  15 . Each of the vertical plates  18  defines a first semicircular concave gap  181  on a bottom portion thereof. A front end of each of the vertical plates  18  connects with a reverse side of the rear portion  142 . A retaining plate  19  extends downward from the reverse side of the top board  11 . Two ends of the retaining plate  19  respectively connect with rear ends of the vertical plates  18  adjacent to the sideboards  12 . The retaining plate  19  defines a retaining hole  191  at a top portion thereof. 
   Referring to  FIG. 1 , the bearing frame  20  has a base wall  21 , two sidewalls  23  extending upward from opposite sides of the base wall  21  and a rear wall  26  extending upward from a rear side of the base wall  21  and connecting with the sidewalls  23 . A front portion of the base wall  21  defines two first locating holes  25  at opposite sides thereof. The front portion of the base wall  21  stretches forwardly from a middle portion thereof to form a tongue portion  22  defining a second hollow locating pillar  221  downward. Each of the sidewalls  23  defines a second semicircular concave gap  231  thereon. An opening  242  is defined in the middle of the rear wall  26 . A locking portion  24  extends upward from the rear of the base wall  21  corresponding to the middle position of the opening  242 . A top end of the locking portion  24  protrudes backward to form a hook portion  241  thereon. 
   With reference to  FIG. 1  and  FIG. 3 , the plug module  40  includes a pair of retaining blocks  42  keeping a distance from each other. Each of the retaining blocks  42  is of substantially square-shape and defines an arc-shaped surface  421  which smoothly connects a bottom surface with a rear surface of the retaining block  42 . A central shaft  41  transversely passes through the center of the retaining blocks  42  and two ends thereof respectively protrude outside. Two sheet-shaped connecting terminals  43  longitudinally run through the middle of the retaining blocks  42  and the central shaft  41  respectively. The connecting terminal  43  has an inserting portion  431  at front of the retaining block  42  and a projecting portion  432  extended out of the back portion of the retaining block  42 . 
   Referring to  FIG. 1 , each of the resilient pieces  50  is conductive and has a planar locating portion  51  defining two second locating holes  511  therein. A front end of the locating portion  51  perpendicularly extends downward to form a contact portion  52 . A protrusion  521  is projected forwardly from the contact portion  52 . An arc-shaped resisting portion  53  smoothly extends rearward and upward from a rear end of the locating portion  51 . 
   The PCB  60  defines two pairs of inserting holes  61  at a front end thereof and a plurality of fixing notches  62  at opposite sides thereof. 
   Each conductive member  70  is of substantial M-shape. The conductive member  70  has a receiving groove  71  which gradually becomes wider and wider from top to bottom. Two inserting pins  72  extend downward from opposite sides of the receiving groove  71 . 
   The lower casing  80  defines a plurality of wedging blocks  81  on a bottom surface thereof and connected with opposite sides thereof. 
   Please refer to  FIG. 1  to  FIG. 4 . In assembly, the locating portions  51  of the resilient pieces  50  are respectively disposed on the opposite sides of the base wall  21  of the bearing frame  20 . The resisting portion  53  is disposed above the base wall  21 . The second locating hole  511  disposed at the rear of the locating portion  51  and the first locating hole  25  of the bearing frame  20  have the same axle center. The plug module  40  is placed on the bearing frame  20 . The two ends of the central shaft  41  are respectively received in the second concave gaps  231 . The retaining blocks  42  are disposed on the resisting portions  53 . The arc-shaped surface  421  of the retaining block  42  touches a surface of the resisting portion  53 . Then the combination of the bearing frame  20 , the plug module  40  and the resilient pieces  50  couples with the upper casing  10 . The first locating pillar  16  is inserted in the second locating pillar  221  of the bearing frame  20 . Then the locating screw  30  is mounted in the second locating pillar  221  for fixing the bearing frame  20  with the upper casing  10 . The locating posts  17  are respectively disposed in both the second locating holes  511  and the first locating holes  25 . The vertical plates  18  adjacent to the sideboard  12  are coupled with the sidewalls  23  of the bearing frame  20 . The two ends of the central shaft  41  are placed in the first concave gaps  181  and the second concave gaps  231 . The retaining blocks  42  are disposed in the inserting grooves  15  and the inserting portions  431  respectively protrude outside. The hook portion  241  of the bearing frame  20  is located in the retaining hole  191  of the upper casing  10 . The conductive members  70  are located on the PCB  60  for electrical connection. The inserting pins  72  are respectively inserted in the inserting holes  61 . Then the contact portions  52  of the resilient pieces  50  are received in the receiving grooves  71 . The PCB  60  is mounted in the lower casing  80 . The wedging blocks  81  engage with the fixing notches  62 . 
   Please refer to  FIG. 5  and  FIG. 6 . When the power supply adapter  1  is in use, the inserting portions  431  of the connecting terminals  43  of the plug module  40  are raised erectly to connect with other electronic apparatus. At this time, the projecting portions  432  of the connecting terminals  43  compress the resisting portions  53  of the resilient pieces  50 , which not only enable the electrical connection between the PCB  60  and the connecting terminals  43 , but also ensure the inserting portions  431  stably connect with the electronic apparatus because of the resisting portions  53  exerting elastic force upon the projecting portions  432 . When the power supply adapter  1  is not in use, the inserting portions  431  are laid and received in the receiving recess  14  of the upper casing  10  for conveniently being carried. Meanwhile, the projecting portions  432  come off the resisting portions  53 . 
   As described above, the power supply adapter  1  of the present invention utilizes the resilient pieces  50  to attain electrical connection with the PCB  60  and simultaneously fix the inserting portions  431  of the plug module  40 , so that the inserting portions  431  are capable of stably connecting with the electronic apparatus. 
   The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such as another embodiment shown in  FIG. 7 , in which the rear portion  142  of the upper casing  10  extends forward into the receiving recess  14  to divide the receiving recess  14  into two. When the power supply adapter  1  is not in use, the inserting portions  431  are received in the corresponding receiving recesses  14  and located at two sides of the rear portion  142  so as to prevent the inserting portions  431  from being broken and be conveniently carried. Such modifications and variations that may be apparent to those skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.