Patent Publication Number: US-7223126-B2

Title: Plug device with a plug adapter

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a plug device for plugging into a country specific electrical plug receiving socket comprising a base part and at least one country specific electrical plug adapter, adapted to be secured to the base part, for insertion of the plug device into the country specific line socket. 
   THE PRIOR ART 
   In the case of base part it is for example a question of a power supply adapter or the like, which by means of the country specific electrical plug adapter may be connected with distinct country specific line socket outlets, which for instance are different in the USA, in Europe, in Australia or in the United Kingdom. The known country specific plug adapters have country specific characteristics both on the input side and also on the output side: for example a plug adapter for use in the USA may have a base part with a European plug plugged into it in order to provide adaptation to a line socket in the USA. Alternatively for example a plug adapter may be plugged to the base part, such plug adapter having European sockets on the input side and typical Australian plug contacts on the output side. 
   When the known combination, which is loosely plugged together of a base part and a plug adapter is removed from a country specific electrical line socket, then frequently the base part is detached from the plug adapter and the plug adapter must be separately removed from the plug receiving socket, which is frequently mounted in the wall. The known combination of a base part and a plug adapter requires, owing to the plugging together of a plurality of country specific plug-socket combinations, a comparatively large amount of space. 
   Another set of problems arises for the manufacture of plug devices. For different markets, in which respectively country specific, mutually different plug receiving sockets are conventional, it is necessary for different plug device to be manufactured, which for example have different plug contacts for the USA to those in Europe. The manufacture of different plug devices is however complex and comparatively expensive, more particularly in the case of small batches. 
   SHORT SUMMARY OF THE INVENTION 
   One object of the invention is accordingly to design a plug device of the type initially mentioned to have a simple and readily operated adaptation to different country specific line sockets. 
   In order to achieve the object in the case of a plug device of the type initially mentioned there is a provision such that the at least one plug adapter may be locked without using a tool (by hand) in a mounted position with one or more locking means and may be detached from the base part after unlocking the locking means. 
   The plug adapter is able to be simply mounted on the base part and owing to the locking by means of the locking means constitutes a compact structural unit reliably connected with the base part. Following unlocking of the locking means the plug adapter may be removed readily from the base part. Then it is possible to attach a different plug adapter suitable for other country specific conditions to the base part. A plug device in accordance with the invention may have a plurality of country specific plug adapters so that an adaptation of the plug device to country specific line sockets is readily possible without any complications. 
   Further advantageous developments of the invention are defined in the claims and indicated in the description. 
   Preferably the at least one plug adapter is able to be plugged to the base part. Alternatively a screw connection would be possible. In the case of the advantageous plugging technology the base part preferably possesses a plug socket for the plug adapter. Preferably, a plug projection is provided on the plug adapter, which in the mounted state fits into the plug socket. 
   The following measure contributes to the mechanical coherence of the combination comprising the base part and the plug adapter. The plug adapter is in the mounted state essentially not able to be tilted athwart the direction of insertion. This is for example made possible if the plug adapter is fitted deeply into the plug socket and/or ample engagement faces are present for the plug adapter within the line socket and/or at its edge regions. Moreover, guide means, to be explained in the following are provided contributing to providing stability as regards tilting. The locking means for locking the plug adapter must also, in this form of the invention, act essentially oppositely to the insertion direction, while on the contrary a stabilization athwart the insertion direction is less important. The mechanical load on the locking means is reduced as a result. The locking means may be designed to be compact and/or readily operated. 
   The locking means advantageously has at least one detent projection for fitting into a detent socket. The detent projection may for example be arranged on the plug adapter and the detent socket may be arranged on the base part or the other way round. The detent projection and/or a detent socket may be arranged on a resilient actuating element. By actuation of the actuating element the detent projection and the cooperating detent socket are disengaged so that the plug adapter is able to be detached from the base part. On plugging the plug adapter to the base part the resilient actuating element is advantageously automatically disengaged in order, on arriving in the mounted state, automatically spring back so that the detent projection and the detent socket engage again. The actuating element conveniently projects, at least partly, during non-operation past the outer face of the base part and/or the plug adapter. By pressing on the actuating element so that it advantageously essentially moves behind the outer face of the base part or, respectively, of the plug adapter, the plug adapter is unlocked. It is an advantage for the actuating stroke of the actuating element to be so large that accidental operation is prevented. 
   Preferably one single locking means is present. However, a plurality of locking means may be present and for example two locking means may be present on mutually opposite sides of the plug socket or four locking means may be present on each side of a rectangular plug socket. 
   For the electrical connection of the plug socket with the base part it is an advantage to have electrical plug contacts at the plug socket of the base part, such contacts not projecting past the plug socket and fitting into the plug receiving sockets of the plug adapter in the mounted condition. Accordingly the plug contacts are protected from mechanical damage. 
   The plug contact may be optimally adapted to existing electrical features. The plug contacts are preferably proprietary contacts and not common to country specific plugs. For instance, the plug contacts may be thinner than country specific plugs and be electrically conductive or the like along their complete length. 
   Further advantageous developments and convenient forms of the invention will be understood from the following detailed descriptive disclosure of one embodiment thereof in conjunction with the accompanying drawings. 

   
     LIST OF THE SEVERAL VIEWS OF THE FIGURES 
       FIG. 1  shows a partly sectioned side view of a plug device in accordance with the invention having a country specific plug adapter customized for the USA. 
       FIG. 2  shows the plug adapter as in  FIG. 1  and further country specific plug adapters, which are able to be joined by plugging with a base part different to that of  FIG. 1  but otherwise essentially similar to it. 
   

   DETAILED ACCOUNT OF WORKING EMBODIMENT OF THE INVENTION 
   In the case of the plug device  10  illustrated in  FIG. 1  a country specific electrical plug adapter  12  is able to be joined by plugging with a base part  11  so that the plug device may be plugged into a country specific electrical plug receiving wall socket  13 . The base part  11  can comprise an electrical device  14 , as for example an electric lamp, a power pack, a charging device for accumulators or the like. The electrical device  14  may be for example a transformer, an inverter, a rectifier or some electrical adaptation means. The electrical device  14  may operate linearly or with a switching effect. The plug device  10  or respectively the base part  11  are in the present case portable. However in principle designs for stationary and non-portable applications are possible. 
   On the front top region of the base part  11  a plug socket  17  is arranged, into which the plug adapter  12  is able to be plugged. The base part  11  has a housing  60 , for example of plastic, with a front and rear part  61  and  62 . In the interior of the housing  60  the electrical device  14  is arranged. The plug socket  17  constitutes an integral component of the front part  61 . The plug socket  17  is arranged in the front, top region of the front part  61 . Side walls  29  and a floor side  28  of the plug socket  17  are formed by the front part  61  of the housing  60 . The side walls partly project past the front side  63  of the front part  61 . The floor side  28  is on the contrary set back in relation to a front side  63  of the front part  61 . 
   The plug adapter  12  is able to be joined by plugging with the base part  11  and in the present case plugged into it. In the mounted state the plug adapter  12  covers over the plug socket  17 . The fitting together of the plug adapter  12  is extremely simple. The plug adapter  12  is moved in a plugging direction  15  toward the base part  11  until a plug projection of the rear side of the plug adapter  12  fits into a plug socket  17  on the front side of the base part  11 . The internal shape of the plug socket  17  corresponds to the outer shape of the plug projection  16 . The plug projection  16  has, for example, a rectangular outline and the plug socket  17  has a corresponding rectangular inner shape. It will be clear that shapes other than rectangular outer shapes and corresponding inner shapes are possible, as for example circular or elliptical shapes. 
   On introduction into the plug socket  17  sides faces  18  on the plug projection  16  slide along inner side faces  19  of the plug socket  17 . Accordingly the side faces  18  and  19  constitute guide means  20  for angularly aligned guidance of the plug adapter  12  in the assembled position. In the working embodiment this is only possible in one single angular position, in the case of which a locking means  21  for locking the plug adapter  12  on the base part  11  is at the top as illustrated in the drawing. As shown in  FIG. 2 , this angular position is for example set by a guide projection  24  on the bottom inner face  54  of the plug socket, which fits into a guide groove  22  on the bottom side of the plug projection  16 , in the present case on a bottom side face  23  on the plug projection  16 . The guide groove  22  and the guide projection  24  also constitute guide means  20 . 
   The guide means  20  in conjunction with a set back arrangement of plug contacts  23  at the plug socket  17  are responsible for ensuring that on insertion into the plug socket  17  the plug adapter  12  is moved into a particular angular position even prior to the fitting of the plug contacts  25  into the plug receiving sockets  26  of the plug adapter  12 , in which position the plug contacts  25  are opposite to the plug receiving sockets  26  and may fit into the same. The mechanical load on the plug contacts  25  and, respectively, the plug receiving sockets  26  is accordingly small. The plug receiving sockets  26  are integrated in the plug adapter  12 . 
   The plug contacts  25  and the plug receiving sockets  26  constitute an electrical connection between the base part  11  and the plug adapter  12 . The electrical plug contacts  25  are connected electrically with the electrical device  14 . In the assembled state therefore country specific electrical plug contacts  27 , which project forward past the plug adapter  12 , are electrically connected with the device  14 . 
   The plug contacts  25  project perpendicularly to the front of the bottom side  28  of the plug socket  17 . The plug contacts  25  however do not project past the plug socket  17 . The plug contacts  25  are shorter than the side walls  29  of the plug socket  17  so that same are protected against mechanical damage by the side walls. This measure furthermore means that on insertion of the plug adapter  12  into the base part  11  firstly the outer side faces  18  of the plug projection  16  are guided into the predetermined angular position by the inner side faces  19  of the side walls  29 . 
   The plug receiving sockets  26  of the plug adapter  12  may, as in the working example, be funnel-like and flared outwards toward the insertion side so that the plug contacts  25  may be more readily fitted into the plug receiving sockets  26 . 
   When the plug projection  16  is completely fitted into the plug socket  17 , the front side  30  of the plug projection  16  will abut the floor side  28 . In the present case the sides  28  and  30  have their faces resting against each other over large areas in the assembled state of the plug adapter  12 . Furthermore the side faces  18  and  19  lie against each other over large areas and the guide projection  24  fits into the guide groove  22  so that generally there is a firm engagement of the plug adapter  12  with the base part. This firm connection of the plug adapter  12  with the base part  11  is also ensured by the fact that in the assembled state a lateral projection  31  on the plug adapter  12  engages terminal sides  32  of the side walls  29  of the plug socket  17  essentially over a large flat area. The lateral, in the present case peripheral, projection  31  is for example like a collar. The lateral projection  31  is constituted by a front region  34  of the plug adapter  12 , which has a larger outer periphery than a rear region  35  of the plug adapter  12 . The depth of the projection  31  is essentially equal to the thickness of the side walls  29  so that in the assembled position of the plug adapter  12  there is an essentially smooth transition from the base part  11  to the plug adapter  12  and the base part  12  constitutes a homogeneous structural unit with the plug adapter  12 . 
   As already explained, in the assembled position numerous faces on the plug adapter  12  engage corresponding face on the base part  11 , as for example the side faces  18  and  19 , the sides  28  and  30 , the projection  31  and the end faces  32  and furthermore the guide means  20  fit into each other so that the plug adapter  12  can not, for all intents and purposes, be tilted athwart the plugging direction  15 . The locking means  21  must accordingly act essentially oppositely to the plugging direction  15 . It is sufficient for the present design of the plug device  10  in accordance with the invention to have only one single locking means  21 . It will be clear that in principle a plurality of locking means would be possible as well, for example a second locking means could be provided on the side, which is opposite to the locking means  21 , of the plug adapter  12  (not illustrated). 
   The locking means  21  is in the present case designed in the form of a detent locking means. In the assembled state of the plug adapter  12  a detent projection  36  on the plug adapter  12  fits into a detent recess  37  on the plug socket  17 . The detent projection  36  is arranged on a resilient actuating element  38 . The detent projection  36  is made oblique and wedge-like tapering toward the front side  30  of the plug adapter  12  so that on insertion of the plug projection  16  into the plug socket  17  the wedge face of the detent projection  36  slides along the top inner edge  39  of the top side wall  29  and urges the actuating element  38  toward the interior of the plug adapter  12 . In the assembled state of the plug adapter  12  the actuating element  38  springs back outward  36  so that the detent projection  36  fits into the detent recess  37  plug adapter  12  is locked to the base part  11 . The detent projection  36  and the detent recess  37  locks the plug adapter  12  effective in the plugging direction  15 . 
   It will be clear that a reversed arrangement is also possible, in the case of which for example a resilient actuating element is arranged on the base part and a stationary detent recess is arranged on the plug adapter. Furthermore a plurality of detent recesses could be provided as well and there could be detent projections cooperating with them. 
   In the present case one actuating projection  40  of the actuating element  38  projects upward to the front of the top face of the base part  11  and, respectively, of the plug adapter  12  and may be readily operated. For unlocking the plug adapter  12  the actuating element  38  is thrust by pressing on the actuate projection  40  toward the interior of the plug adapter  12  so that the detent projection  36  is disengaged from the detent recess  37 . Then the plug adapter  12  may be pulled off the base part  11  in a direction opposite to the plugging direction  15 . 
   The actuating element  38  is designed like a resilient lug or tongue. It is pivoted for resilient movement on the front side  30  of the plug projection  16 . In the present case it constitutes an integrated component of a rear housing part  41  of the plug adapter  12 , which constitutes the plug projection  16 . 
   The rear housing part  41  and furthermore preferably a front housing part  42  constituting the front part  35 , of the plug adapter  12  are preferably manufactured of plastic or some other electrically insulating material. The housing parts  41  and  42  are for example joined together by bonding and/or by joint means. The front region  34  has a country specific design and is designed as a sort of country specific plug, something which will be clear on comparison with plug adapters  43  through  45  shown in  FIG. 2  which are alternatives to the plug adapter  12 . The rear regions  35  of the plug adapters  12 ,  43 ,  44  and  45  are essentially similar in structure, whereas the respective front regions  34 ,  46 ,  47  and  48  are different, that is to say they are country specific in design. The plug adapters  12 ,  43 ,  44  and  45  serve for country specific adaptation of the plug device  10  for line sockets in the USA, Europe, Australia and the UK. 
   In the case of the plug adapters  12  and  43  the polarity of the plug contacts  27  and, respectively,  49  is irrelevant. Accordingly in the case of such plug adapters  12  and  43  there is no need to ensure that they may be secured in a single, unique angular position on the base part  11 . The plug adapters  12  and  43  may for example also be arranged in an opposite angular position which is turned through 180 degree on the base part, if for example, departing from the design in accordance with the working example, mutually symmetrically arranged locking means were to be provided like the locking means  21 . 
   The case is different with the plug adapters  44  and  45 , in which electrical polarity is important, at least as regards use with a country specific line socket. In this case it can be an advantage for example the plug adapters  44  and  45  only to be able to be fitted in a unique angular position on the base part  11 . 
   The plug adapter  45  provided for the UK has, in addition to the electrically conductive plug contacts  50 , which are electrically connected with the plug contacts  25  of the base part in the assembled state, a contact pin  51  which in the present case is not electrically conductive. Given a suitable electrical design of the base part  11 , for example in the case of using an electrically non-insulating housing or the like, an electrical protective contact might be necessary. Then the contact pin  51  could be manufactured of electrically conductive material as for example metal and be electrically connectable by means of a plug contact (not illustrated in the figure) present in addition to the plug contacts  25 . 
   The plug contacts  25  are in the present case proprietary electrical contacts which are not country specific. They are optimally adapted to the electrical properties of the plug device  10 . In the case of such plug contacts mechanical strength is not important, since the plug adapter  12 , for example owing to the nature of its housing, the guide means  20  and the like, may be connected with the base part  11  so as to resist mechanical loads. The plug contacts  25  are for example substantially thinner than country specific plug contacts for example the plug contacts  27 . Moreover, they may be electrically conductive over their entire outer periphery, something which reduces the electrical resistance between the plug contacts  25  and the plug receiving sockets  26 . In order to improve the electrical insulation the plug contacts  25  may be comparatively widely spaced apart, and for example as far apart as plug contacts  49  of the plug adapter  43  provided for Europe. 
   In addition to the already explained guide means  20  additional guide means can be provided, as for instance further guide projections  53  on the inner side faces  19  of the plug socket  17 , which correspond at mating guide grooves  52  to the plug adapters  12 ,  43 ,  44  and  45 . As shown in chained lines for example guide grooves  52  may be provided on the plug adapter  43 . 
   In  FIG. 2  a base part  70  is illustrated which is an alternative to the base part  11 . Essentially the base part  70  is similar to the base part  11  so that functionally equivalent components have the same reference numerals. The housing of the base part  70  is smaller than the housing  60  of the base part  11 . The base part  70  has a connection cable  71 , with which the base part  70  may for example be connected with a mobile telephone electrically. The base part  70  comprises for example a charging adapter, with which a charging current may be provided for charging accumulators of the mobile telephone, not illustrated. 
   It will be clear that other housing configurations are possible besides the configuration of the base parts  11  and  70 , as for instance cylindrical or barrel-like housing forms.