Patent Publication Number: US-2005136745-A1

Title: Adaptor DC output plug

Description:
BACKGROUND OF THE INVENTION  
      (a) Field of the Invention  
      The present invention is related to a DC output plug of an adaptor, and more particularly to one that is provided with a locking device to prevent mistake of polarities while the DC output plug and a connector are plugged into each other.  
      (b) Description of the Prior Art  
      The primary purpose of a portable power supply is to rectify and convert the commercial power source into DC for supplying power to a power-receiving device including printer, radio, and modem. Adaptor and charger are two essential types of the portable power supply.  
      As illustrated in  FIG. 1  of the accompanying drawings, a construction of an adaptor  1  generally available in the market is essentially comprised of a case  11 , one end of the case  11  relates to a power-receiving jack  111 . A cable  162  with one end provided with a connector  161  to plug into the power receiving jack  111  with an AC plug  12 , and another plug  163  to plug into a wall socket (not illustrated) to constitute a continuity for receiving the commercial power source. Another end of the case  11  relates to a power outlet jack  112  connected to a power cable  14  and a DC output plug  15  to be inserted into a connector  21  of a power-receiving device  2  so to supply the converted power to the power-receiving device  2 . The DC plug  15  is adaptable to the insertion by the connector  21  in various forms for the adaptor  1  to supply power to the power-receiving device. However, when the connector  21  is plugged into the DC output plug  15  as illustrated in FIG.  2 , both of a positive terminal  211  and a negative terminal  212  must be respectively and exactly plugged into a positive and a negative jacks  151 ,  152 . However, either on the DC output plug  15  or the connector  21  there is the absence of a significant marking of the polarities to facilitate the plug in with correct polarities fail the normal power supply by the adaptor or even damage the internal circuit of the power-receiving device.  
     SUMMARY OF THE INVENTION  
      The primary purpose of the present invention is to provide an improved construction for the DC output plug of an adaptor to avoid mistakes of plugging into wrong polarities. To achieve the purpose, the adaptor is essentially comprised of a case. One end of the case relates to a power-receiving end and the other end of the case is connected to a cable and the DC output plug. The DC output plug is adaptable to a plug from various forms of a power-receiving device so to supply the converted power to the power-receiving device. Wherein, a locking device is formed at where the DC output plug contacts the connector of the power-receiving device plugged into the DC output plug to maintain unity of the plug of the connector and the DC output plug while permitting the proper conduction between the positive and negative polarities and those from the connector. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of an adaptor of the prior art.  
       FIG. 2  is an exploded view showing a DC output plug and a connector of the adaptor of the prior art are about to connecting to each other.  
       FIG. 3  is an exploded view showing that a DC output plug and a connector of the present invention are about to connecting to each other.  
       FIG. 4  is a schematic view showing that the DC output plug and the connected of the present invention are connected to each other.  
       FIG. 5  is a schematic view showing another working status of the DC output plug and the connector of the present invention are connected to each other.  
       FIG. 6  is a schematic view showing another preferred embodiment of the present invention.  
       FIG. 7  is a schematic view showing another preferred embodiment yet of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The present invention relates to an improved construction of a DC output plug of an adaptor  1 . The adaptor  1 , the same as that illustrated in  FIG. 1 , essentially includes a case  11  with one end of the case  11  related to a power receiving end  111  to receive the power and the other end of the case  11  related to a power output end  112  connected to a power cable  14  and a DC output plug  17 . The DC output plug  17  permits to be plugged by a connector from a power-receiving device  2  of various forms so to supply the converted power to the power-receiving device  2 .  
      As illustrated in  FIGS. 3 and 4 , a locking device  3  is provided at where both of the DC output plug  17  and the connector  22  are plugged into each other. The locking device  3  is comprised of a locking bit  31  provided on the DC output plug  17  and a slot  32  disposed on the connector  22  at where in relation to the locking bit  31  to maintain the unity of the DC output plug  17  and the connector plugged into each other. Accordingly, both of a positive and a negative terminals  221 ,  222  of the connector  22  are correctly inserted into both corresponding positive and negative sockets  171 ,  172  of the DC output plug  17  while conducting the positive and the negative polarities of the DC output plug  17  and the connector  22  to avoid mistake of polarities. The shape of the locking bit  31  and the locking slot  32  may be made as that illustrated in  FIG. 7 . If the user makes mistake about the polarities when plugging the connector  22  into the DC output plug  17 , the locking bit  31  fails to engage the locking slot  32  thus to frustrate the connection of the connector  22  into the DC output plug  17  as illustrated in  FIG. 5 . Therefore, both of the DC output plug  17  and the connector  22  are prevented from being conducted to avoid damage to internal circuit of the power-receiving device.  
      Furthermore, the DC output plug  17  is adaptable to the connector  22  of different form. As illustrated in  FIG. 6 , the locking device  3  as illustrated in  FIG. 6  has its locking bit  31  provided to the connector  22  and the locking slot  32  provided to the DC outlet plug  17  at where in relation to the locking bit  31  when both of the DC output plug  17  and the connector contact each other.  
      The improved construction of the DC output plug of the adapter by the installation of the locking device assures of the correct conduction between both polarities of the DC output plug and both polarities of the connector to avoid mistake about the polarities. Therefore, this application for a utility patent is duly filed; however, it is to be noted that the preferred embodiments disclosed in the specification and the accompanying drawings are not limiting the present invention; and that any construction, installation, or characteristics that is same or similar to that of the present invention should fall within the scope of the purposes and claims of the present invention.