Abstract:
A power adapter has a main body. A top of the main body defines a recess and an annular sidewall enclosing the recess. The annular sidewall has a sliding recess extending along the circumference of an inner surface thereof. A rotation-proof component defines a rotation-proof portion received in the sliding recess. A plug rotatably and detachably mounted to the main body defines a protruding portion at one side thereof. The protruding portion is capable of reciprocally sliding in the sliding recess and elastically pressing the rotation-proof portion for passing through the rotation-proof portion and then being restrained from reverse rotation because of restoration of the rotation-proof portion.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a power adapter, and more particularly to a power adapter having a structure which is convenient to assemble and disassemble a plug with a main body thereof and which occupies a relatively small space. 
   2. The Related Art 
   Generally, a power adapter is always used for adapting different sockets provided in different countries when one traveling all over the world. Therefore, a plug of the power adapter for connecting with the socket also must be exchangeable for adapting different sockets. The power adapter generally includes a main body and a plug mounted to the main body. The main body has an opening; a side of the plug has an arm with a -protruding portion located on an end thereof away from the main body. A guiding recess in the main body can receive both the arm and the protruding portion so that the protruding portion is wedged into the opening for preventing the plug from reverse rotation. 
   However, such engaging structure needs to press the protruding portion in assembly and disassembly, which is quite inconvenient for user to assemble and disassemble the plug. Furthermore, such engaging structure occupies such big a space that the volume of the power adapter is increased, which can not meet people&#39;s requirement of miniaturization and light-weighting. In addition, it is also inconvenient for user to carry the power adapter in traveling. So a power adapter having an engaging structure which is convenient to assemble and disassemble a plug with a main body thereof and which occupies a relatively small space is required. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is to provide a power adapter having a structure which is convenient to assemble and disassemble a plug with a main body thereof and which occupies a small space. A top of the main body defines a recess and an annular sidewall enclosing the recess. The annular sidewall has a sliding recess extending along the circumference of an inner surface thereof. A rotation-proof component defines a rotation-proof portion received in the sliding recess. A plug rotatably and detachably mounted to the main body defines a protruding portion at a side thereof. The protruding portion is capable of reciprocatingly sliding in the sliding recess and elastically pressing the rotation-proof portion for passing through the rotation-proof portion and then being restrained from reverse rotation because of restoration of the rotation-proof portion. 
   As described above, the plug is assembled to an end of the main body, and the rotation-proof portion is received in the sliding recess. When the plug is rotated with respect to the main body, the protruding portion presses elastically the rotation-proof portion and slides through the rotation-proof portion, and then, the rotation-proof portion restores its elasticity and abuts against the protruding portion for preventing the plug from reverse rotation. When the plug needs to disengage from the main body, a reverse force is applied to the plug so that the protruding portion elastically presses the rotation-proof portion and slides back in initial way. Such structure simplifies the process of assembly and disassembly of the plug with the main body and is more convenient to assemble and disassemble. Furthermore, such structure occupies a relatively small space so as to be capable of reducing weight and volume of the power adapter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of an embodiment thereof, with reference to the attached drawings, in which: 
       FIG. 1  is a schematic view showing a power adapter in an embodiment according to the present invention, wherein a plug of the power adapter is shown in a manner of cross-sectional view; 
       FIG. 2  is a perspective view of a main body of the power adapter shown in  FIG. 1  while seen from a top view; 
       FIG. 3  is a perspective view of a rotation-proof component of the power adapter shown in  FIG. 1  while seen from a top and side view; 
       FIG. 4  is a perspective view of a plug body of the power adapter shown in  FIG. 1  while seen from a top view; 
       FIG. 5  is a perspective view of a conducting terminal of the power adapter shown in  FIG. 1  while seen from a bottom and side view; 
       FIG. 6  is a perspective view of a connecting terminal of the power adapter shown in  FIG. 1  while seen from a bottom and side view; 
       FIG. 7  is a perspective view of a cover of the power adapter shown in  FIG. 1  while seen from a top view; 
       FIG. 8  is a perspective view of the cover of the power adapter shown in  FIG. 7  while seen from a bottom and side view; and 
       FIG. 9  is a schematic view illustrating the state of a rotation-proof portion when a protruding portion slides in a sliding recess. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With reference to  FIG. 1 , a power adapter includes a case  10  and a plug  20  engaged with the case  10 . The case  10  has a main shell  110 , a main body  120  mounted in the main shell  110  and a plurality of main terminals  130  received in the main body  120 . 
   Please refer to  FIG. 1  and  FIG. 2 , the main body  120  is of a cylindrical shape and defines a recess  121  with a bottom surface  1211  defined therein and an annular sidewall  122  enclosing the recess  121 . The annular sidewall  122  defines an annular inner surface  1221 ; the inner surface  1221  is recessed inward to form two fixing recesses  123  and two receiving recesses  124 , respectively and symmetrically. The fixing recess  123  includes a guiding recess  1231  extending upward and downward and passing through a top of the annular sidewall  122 , and a sliding recess  1232  communicating with the guiding recess  1231 . The sliding recess  1232  extends along the circumferential direction of the annular sidewall  122  and is adjacent to the bottom surface  1211 . The sliding recess  1232  defines an upper side  1233  and a closed end  1234  adjacent to the receiving recess  124 . The upper side  1233  protrudes axially to form two protrusions  1235 . The protrusion  1235  is disposed to be adjacent to the inner surface  1221 . The bottom surface  1211  extends upward to form a restricting portion  1212  and a blocking portion  1213 . The restricting portion  1212  is located in the receiving recess  124  and near the closed end  1234  of the sliding recess  1232 . The blocking portion  1213  is spaced away from the closed end  1234  a short distance. The main terminals  130  are mounted to the bottom surface  1211 . 
   Please refer to  FIG. 1  and  FIG. 3 , the case  10  further has a rotation-proof component  140  disposed in the fixing recess  123  and defining a connecting plate  141 . The connecting plate  141  is of a rectangular shape. One side of the connecting plate  141  bends and extends to form a fixing portion  142 . The fixing portion  142  has at least one mating opening  1421  corresponding to the restricting portion  1212  at the bottom surface  1211 . The other side of the connecting plate  141  extends upwardly and obliquely and then bends downward to form an extending portion  143  of an arc shape. The extending portion  143  and the fixing portion  142  are arranged at two opposite sides of the connecting plate  141  unsymmetrically. A side of the extending portion  143  has two buckling notches  1431  corresponding to the protrusions  1235 . A free end of the extending portion  143  extends downward and bends upward to form a rotation-proof portion  144 . The rotation-proof portion  144  extends to show an arc shape opposite to the extending portion  143 . A free end of the rotation-proof portion  144  bends upward to form a buckling end  1441  with a sharp angle formed therebetween for elastically abutting the upper side  1233  of the sliding recess  1232 . 
   In assembly, the fixing portion  142  is located at the bottom surface  1211  and partly received in the receiving recess  124 , and the mating opening  1421  has the restricting portion  1212  restricted therein for preventing the fixing portion  142  from moving radially and outwardly. The connecting plate  141  is disposed between the closed end  1234  and the blocking portion  1213  for fixing the rotation-proof component  140  in place. The extending portion  143  and the rotation-proof portion  144  are both received in the sliding recess  1232 ; the extending portion  143  is adapted for cooperating with the rotation-proof portion  144  to restrain the protruding portion  216  from reverse rotation and attached to the upper side  1233 ; and the buckling notches  1431  engage with the protrusions  1235  for preventing the extending portion  143  from moving inwardly. The buckling end  1441  is forcefully pressed against the upper side  1233  for reducing the elastic deformation of the rotation-proof portion  144 . 
   Please refer to  FIG. 1  and  FIG. 4 , the plug  20  includes a plug body  210 , two conducting terminals  220  and two connecting terminals  230  and a cover  240 . The plug body  210  is of a disc shape and defines a top surface  211 . The top surface  211  has two conducting recesses  212  defined therein to receive the conducting terminals  220 . The conducting recess  212  includes a first cavity  2121  and a second cavity  2122  extending downward to pass through the plug body  210  from a bottom surface of the first cavity  2121 . The first cavity  2121  is of a fan shape. The second cavity  2122  of also a fan shape is disposed near one end of the first cavity  2121  and narrower than the first cavity  2121 . The end of the bottom surface of the first cavity  2121  extends upward to form a positioning portion  213  adjacent to an end of the second cavity  2122 . The positioning portion  213  is used to position the conducting terminal  220 . In this embodiment, the positioning portion  213  is of a short-pillar shape. The plug body  210  further has a pair of supporting portions  214  adjacent to the other end of the first cavity  2121 . A top portion of the supporting portion  214  is of an arc shape. A stopping portion  215  extends upward from the top surface  211  and is disposed between the two supporting portions  214 . A bottom of the plug body  210  extends outward to form a protruding portion  216  corresponding to the fixing recess  123 . 
   Please refer to  FIG. 1  and  FIG. 5 , the conducting terminal  220  received in the conducting recess  212  defines a first contacting plate  221  received in the first cavity  2121  for electrically connecting with the main terminal  130 . The first contacting plate  221  is of a fan shape. One end of the first contacting plate  221  bends downward and extends to form a second contacting plate  222  overlapping the first contacting plate  221 . The second contacting plate  222  is similar in shape to the first contacting plate  221  and spaced away from the first contacting plate  221  with a certain distance. The second contacting plate  222  is shorter than the first contacting plate  221  and bends upward to contact the first contacting plate  221 . The other end of the basic plate  221  has a positioning hole  223  defined therein to mate with the positioning portion  213  for positioning the conducting terminal  220  in the conducting recess  212 . 
   Please refer to  FIG. 1  and  FIG. 6 , the connecting terminal  230  located on the plug body  210  defines a base  231 . One end of the base  231 , which is of an arc shape, has a contacting portion  2311  used for electrically connecting with the second contacting plate  222 . The other end of the base  231  is assembled with a connecting portion  232  for electrically connecting with a socket (not shown). In this embodiment, there are two bases  231  connected together by a linking portion  233 . The linking portion  233  is of a column shape. A side of the linking portion  233  has a bump  2331  corresponding to the stopping portion  215  for preventing the connecting terminal  230  from rotation. 
   Please refer to  FIG. 1  and  FIGS. 7-8 , the cover  240  coupled with the plug body  210  defines an upper surface  241  and a gradient surface  242  connected with the upper surface  241 . The upper surface  241  has two connecting slits  243  corresponding to the connecting portion  232  for allowing the connecting portion  232  passing therethrough. Each of the connecting slits  243  extends toward the gradient surface  242  to form a holding recess  244 . The holding recess  244  passes through the gradient surface  242  and is used to receive the connecting portion  232  when the power adapter is not in use. The upper surface  241  extends downward to form a mating portion  245 . The mating portions  245  are arranged at two sides of the connecting slit  243  for coupling with the linking portion  233 . 
   Please refer to  FIGS. 1-3  and  FIG. 9 , when the user wants to assemble the case  10  and the plug  20 , firstly, the plug  20  has to be adjusted to be in a first position, where the protruding portions  216  are respectively wedged into the guiding recesses  1231 . Then the user can clockwise rotate the plug  20  an angle with respect to the case  10  so that the plug  20  will be fixed in the case  10 . In this process, the protruding portion  216  presses the rotation-proof portion  144  upward so that the rotation-proof portion  144  deforms elastically, and then the protruding portion  216  slides through the rotation-proof portion  144 . Then the rotation-proof portion  144  restores its elasticity so as to abut against the protruding portion  216  for restraining reverse rotation thereof. Thus the plug  20  can be mounted to the case  10  steadily. When the plug  20  needs to take away from the case  10 , a counterclockwise force is applied to the plug  20  such that the rotation-proof portion  144  is elastically pressed back; the protruding portion  216  slides back to the first position in initial way so that the plug  20  disengages from the case  10 . 
   As described above, the plug  20  is assembled to an end of the main body  120 , and the rotation-proof portion  144  is received in the sliding recess  1232  of the annular sidewall  122 . When the plug  20  is rotated with respect to the case  10 , the protruding portion  216  elastically presses the rotation-proof portion  144  upward and then slides through the rotation-proof portion  144 . After that, the rotation-proof portion  144  restores its elasticity and abuts against the protruding portion  216  for preventing the plug  20  from reverse rotation. When the plug  20  needs to disengage from the case  10 , a counterclockwise force is applied to the plug  20  so that the protruding portion  216  slides back in initial way. Such structure simplifies the process of assembly and disassembly of the plug  20  with the case  10  and is more convenient to assemble and disassemble. Furthermore, such structure occupies a relatively small space so as to be capable of reducing weight and volume of the power adapter. 
   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 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.