Abstract:
A potential switching apparatus for a power adapter which transforms input power to output power delivered through a power output cord. The potential switch apparatus switches the potential of the output power. It includes a first body and a second body located on the power output cord. The first body has a first contact and a second contact. The second body has a switch element connectable to the first contact to deliver the output power at a first potential and connectable to the second contact to deliver the output power at a second potential. Thus the potential of the output power can be switched. The present invention improves the conventional potential switch device on the power adapter that is too bulky in size.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a potential switching apparatus for power adapter and particularly to a switching apparatus to switch output potentials of a power adapter. 
     BACKGROUND OF THE INVENTION 
     A power adapter aims to transform input power to output power to supply an electronic device. A wide variety of electronic devices on the market require electric power of differential potentials. In order to make the power adapter to supply power to various types of electronic devices, the general approach is like the one shown in  FIG. 1  in which a power adapter  100  is equipped with a horizontal switch  101  and a potential scale  102  indicating potential values. Users can move the horizontal switch  101  to adjust output power potential according to the electronic device connecting to the power adapter  100  to meet requirement thereof. The horizontal switch  101  switches the potential by sliding. Such a movement often cannot position at an accurate potential, but rather between two potential values of the potential scale  102 . As a result, an inaccurate output potential is delivered from the power adapter  100 . 
     To solve the aforesaid problem, R.O.C. patent No. M336623 discloses a dual-input power supply with adjustable output voltage, in which including a case with a window formed thereon, a circuit board held in the case, a voltage regulation knob electrically connected to the circuit board and a rotary wheel with voltage adjustment numerals formed thereon visible through the window. The voltage regulation knob is coupled with a rotary stem of the rotary wheel. To switch the output power potential, turn the rotary wheel and the rotary stem and drive the voltage regulation knob turning on the circuit board. Through the voltage adjustment numerals on the rotary wheel accurate output power of the power adapter can be set and delivered. 
     While the aforesaid conventional techniques can switch the potentials of output power, the switch is located on the case of the power adapter and connected to the circuit board in the power supply. The circuit board has to be made at a larger size to accommodate wiring and the switch. As a result, the size of the power adapter is larger and the production cost also is higher as well. The larger size also makes carrying difficult and takes too much space. 
     SUMMARY OF THE INVENTION 
     Therefore the primary object of the present invention is to solve the aforesaid disadvantages by providing a potential switching apparatus for power adapters that not only can switch output power potential also can be made at a smaller size and a lower production cost. 
     The potential switching apparatus for power adapters according to the present invention aims to transform input power to output power and switch the potential of the output power. It includes a first body and a second body located on a power output cord. The first body has a first contact and a second contact. The second body has a switch element which is connectable to the first contact to form a first potential of the output power and also connectable to the second contact to form a second potential of the output power. 
     By means of the present invention carrying of the power adapter is easier. It also makes the power adapter smaller to save space. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a conventional power adapter. 
         FIG. 2  is a perspective view of the present invention. 
         FIG. 3  is a partial exploded view of the present invention. 
         FIGS. 4A and 4B  are exploded views of the present invention. 
         FIG. 5  is a sectional view of the present invention. 
         FIGS. 6A-6C  are schematic views of the present invention in use condition- 1 . 
         FIGS. 7A-7C  are schematic views of the present invention in use condition- 2 . 
         FIGS. 8A-8C  are schematic views of the present invention in use condition- 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Below are described in detail the technical contents of the present invention. 
     Please referring to  FIGS. 2-4B , the potential switching apparatus of the present invention is adopted for use on a power adapter  1  which has a power input cord  10  and a power output cord  11  to transform input power to output power delivered through the power output cord  11 . The potential switching apparatus  2  is located on the power output cord  11  to switch the potential of the output power, which has a first body  30  and a second body  20 . In an embodiment of the present invention, the power output cord  11  includes a first cable  110  running through the first body  30  and a second cable  111  running through the second body  20 . The first body  30  has an upper case  31  and a lower case  32  that correspond to each other and are coupled together. The first case  30  contains a shifting element  40  which has a coupling member  41  wedged in a coupling trough  320  of the lower case  32 . The upper case  31  has a braking portion  311  holding the upper edge of the shifting element  40 . The shifting element  40  is an adapter circuit board and has a plurality of power ports  42  and  43  linking to the first cable  110  and second cable  111 , and also has a first contact  44  and a second contact  45 . The second body  20  has a turning axle  21  running through the shifting element  40  and forming a turning displacement against the shifting element  40 . The second body  20  further has a switch element  64  connecting to the first contact  44  in regular conditions to form a first potential for the output power. The switch element  64  can be moved away from the first contact  44  in the turning displacement of the second body  20  to connect the second contact  45  to switch the output power at a second potential. 
     In order to switch the output power at the second potential, when the second body  20  goes through the turning displacement and prevent the second body  20  from turning easily under an external force and resulting in change of the output power potential, the first body  30  and the second body  20  have a retaining member  50  and a switch stem  60  running through the retaining member  50  to form an anchoring effect. The turning axle  21  of the second body  20  also runs through the retaining member  50  and can generate a displacement against the retaining member  50  and the shifting element  40 . The turning axle  21  has a detent member  22  at one end thereof to resist the shifting element  40  during the displacement. The switch stem  60  and the second body  20  have respectively a first coupling portion  61  and a second coupling portion  25  that are coupled with each other. The switch stem  60  further has a holding portion  63  to hold the switch element  64 . The first coupling portion  61  and the holding portion  63  are interposed by an anchor portion  62  formed at a diameter greater than the holding portion  63 . The retaining member  50  has fastening stubs  51  and  52  located respectively on an upper edge and a lower edge to wedge in holding troughs  310  and  321  formed on the upper case  31  and the lower case  32 . The retaining member  50  also has a first anchor hole  53  and a second anchor hole  54  to form an anchoring relationship with the anchor portion  62  of the switch stem  60  in the turning displacement. As shown in the drawings, the first anchor hole  53  and the second anchor hole  54  are formed at a size substantially same as the anchor portion  62  and communicate with each other through a restriction zone  58  smaller than the anchor portion  62  to harness the anchor portion  62 . The external diameter of the restriction zone  58  is smaller than the anchor portion  62  but greater than the holding portion  63 . In addition, the retaining member  50  has a retaining cavity  55  to hold a spring  56  and a retaining ball  57  braced by the spring  56 . The second body  20  has two sliding tracks  23  and  24  to confine the retaining ball  57  in the turning displacement. Thereby a click sense is generated during turning to ensure that the second body  20  is turned to a desired position. 
     Refer to  FIGS. 5 through 8C  for the present invention in various use conditions. Initially, the anchor portion  62  of the switch stem  60  is confined by the restricting zone  58  in the first anchor hole  53  of the retaining member  50 , and the retaining ball  57  is pressed by the elastic force of the spring  56  in the sliding track  23  of the second body  20 , and the switch element  64  connects the first contact  44  of the shifting element  40  so that the output power is at the first potential (referring to  FIGS. 5 ,  7 A and  8 A). When there is a desired to switch the output power to the second potential, first, pull the second body  20  with a force to move the switch element  64  away from the first contact  44 ; the detent member  22  of the turning axle  21  of the second body  20  pushes the shifting element  40 , and the anchor portion  62  of the switch stem  60  is moved away from the first anchor hole  53  to release the anchor relationship therewith (referring to  FIG. 6A ); meanwhile, apply a turning force to rotate the second body  20  against the shifting element  40  and the retaining member  50  to remove the retaining ball  57  away from the sliding track  23  and compress the spring  56 ; the holding portion  63  drives the switch element  64  from the first anchor hole  53  through the restriction zone  58  towards the second anchor hole  54  (referring to  FIGS. 6B ,  7 B and  8 B) until the holding portion  63  is moved in the second anchor hole  54 ; the spring  56  pushes the retaining ball  57  to press against another sliding track  24  to ensure that the holding portion  63  is fully positioned in the second anchor hole  54 ; then push the second body  20  again towards the first body  30 , and make the anchor portion  62  of the switch stem  60  to fall in the second anchor hole  54  of the retaining member  50  to form another anchoring relationship therewith. In such a condition, the switch element  64  connects to the second contact  45  of the shifting element  40  so that the output power is at the second potential (referring to  FIGS. 6C ,  7 C and  8 C). The first contact  44  and the second contact  45  may be formed at different impedances to generate different potentials, or when the switch element  64  connects the second contact  45  a feedback path may be formed leading to the power adapter  1  to deliver the output power at the second potential. 
     As a conclusion, the present invention, through the turning displacement of the second body  20  against the shifting element  40  of the first body  30 , allows the switch element  64  to escape the first contact  44  and connect the second contact  45  to switch the potential. Moreover, through the first anchor hole  53  and second anchor hole  54  of the retaining member  50  the switch element  64  can be anchored securely while the second body  20  is turned to allow the power adapter  1  to deliver output power as desired. Furthermore, by means of installing the potential switching apparatus  2  on the power output cord  11 , wiring of the internal circuit board in the power adapter  1  is simplified and the power adapter  1  can be shrunk to reduce production cost. Compared with the conventional techniques, the present invention provides significant improvements such as smaller size and greater portability to make carrying and use easier. 
     While the preferred embodiment of the present invention has been set forth for the purpose of disclosure, modifications of the disclosed embodiment of the present invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the present invention.