Abstract:
A combination includes an AC-adapter and a pin configuration adapter. The AC-adapter includes a plug body having first pins of a first configuration and an AC-adapter housing having a conversion circuit for converting an electric power supplied via the plug body. The pin configuration adapter includes a plug part having second pins of a having configuration different from the first pin configuration, a receptacle part whereto the first pins can be inserted and a pin configuration adapter housing having an internal connection mechanism for electrically connecting the plug body and the plug part. The AC-adapter is provided with engagement grooves which engage with protrusions provided on said pin configuration adapter.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a pin configuration adapter for an AC-adapter, and particularly relates to a pin configuration adapter having a different pin type from that of the AC-adapter and which is, in use, attached to the AC-adapter.  
           [0003]    2. Description of the Related Art  
           [0004]    Generally, a power transformer (AC-adapter) is widely used for supplying power to portable electronic devices and/or for recharging batteries of such electronic devices. The power transformer includes a housing, a plug protruding from the housing, a conversion circuit provided inside the housing and an output cord extending from the housing. In order to plug the power adapter to the power socket, the pins are inserted into the power socket. In the converting circuit, an alternating current supplied from the power socket is converted to a direct current of a predetermined voltage. The obtained direct current is output from the output cord which may be connected to an electronic device.  
           [0005]    Recently, many people bring such devices abroad on their private or business trips. However, there is no global standard configuration for a power socket, and therefore there are various configuration of the power socket for various countries.  
           [0006]    Accordingly, an AC-adapter having a parallel-blade pin configuration conforming to a standard adopted in countries such as Japan, Taiwan and the US, cannot be used in those countries where power sockets are configured to match a pin configuration different from the parallel-blade type. Therefore, the traveller wishing to travel in such a country had to purchase and bring AC-adapters conforming to pin configurations adopted in the country or countries he wishes to travel in.  
           [0007]    However, it is troublesome to prepare AC-adapters of different pin configurations conforming to the domestic standard and to foreign standards. Also, since each of the AC-adapters has a conversion circuit therein, it is comparatively expensive to prepare different types of AC-adaptors. Therefore, it is an economic burden for a user of a portable electronic device to prepare expensive AC-adapters for each standard with different pin configuration.  
           [0008]    In order to overcome the above-mentioned problem, it is known to provide pin configuration adapters having pin configurations different from that of the plug provided on the housing, which may be attached to the AC-adapter. However, the pin configuration adapter of the related art is attached the AC-adapter by simply inserting the pins of the AC-adapter to the pin configuration adapter and therefore an attachment force to the AC-adapter is weak. Therefore, there is a problem that the pin configuration adapter may fall off from the AC-adapter upon insertion to the power socket.  
         SUMMARY OF THE INVENTION  
         [0009]    Accordingly, it is a general object of the present invention to provide an AC-adapter and a pin configuration adapter for an AC-adapter which can solve the above problems.  
           [0010]    It is another and more specific object of the present invention to provide a pin configuration adapter which can be attached to an AC-adapter in a secure manner.  
           [0011]    In order to achieve the above objects, a combination is provided which includes:  
           [0012]    an AC-adapter including:  
           [0013]    a plug body having first pins of a first configuration; and  
           [0014]    an AC-adapter housing having a conversion circuit for converting an electric power supplied via the plug body; and  
           [0015]    a pin configuration adapter including:  
           [0016]    a plug part having second pins of a having configuration different from the first pin configuration;  
           [0017]    a receptacle part whereto the first pins can be inserted; and  
           [0018]    a pin configuration adapter housing having an internal connection mechanism for electrically connecting the plug body and the plug part,  
           [0019]    wherein the AC-adapter is provided with engagement grooves which engage with protrusions provided on the pin configuration adapter.  
           [0020]    With the combination described above, the AC-adapter is prevented from being detached from the pin-configuration adapter when retracting the combination from the power socket. Each of the engagement groove may include a first engagement groove part and a second engagement groove part substantially perpendicular to said first engagement groove part, one of said first and second engagement groove parts extending in a direction perpendicular to a direction of insertion of said first pins into said pin configuration adapter. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a perspective view showing how a pin configuration adapter is attached to an AC-adapter in accordance with a first embodiment of the present invention.  
         [0022]    [0022]FIG. 2 is a perspective view of the AC adapter of the first embodiment of the present invention.  
         [0023]    [0023]FIGS. 3A through 3C are a plan view, a side view and a rear view, respectively, of the AC-adapter of the first embodiment of the present invention shown in a state where a parallel-blade pins are in an accommodated position.  
         [0024]    [0024]FIGS. 4A through 4C are a plan view, a side view and a rear view, respectively, of the AC-adapter of the first embodiment of the present invention shown in a state where a parallel-blade pins are in an extruded position.  
         [0025]    [0025]FIGS. 5A through 5C are a perspective view, a bottom view and a front view, respectively, of the pin configuration adapter of the first embodiment of the present embodiment.  
         [0026]    [0026]FIGS. 6A and 6B are diagrams showing how the pin configuration adapter is attached to the AC-adapter in accordance with the first embodiment of the present invention.  
         [0027]    [0027]FIG. 7 is a schematic view showing an internal structure of the pin configuration adapter of the first embodiment of the present invention.  
         [0028]    [0028]FIG. 8 is a perspective view showing how a pin configuration adapter is attached to an AC-adapter in accordance with a second embodiment of the present invention.  
         [0029]    [0029]FIGS. 9A through 9C are a plan view, a side view and a rear view, respectively, of the AC-adapter of the second embodiment of the present invention shown in a state where a parallel-blade pins are in an accommodated position.  
         [0030]    [0030]FIG. 9D is a rear view of the AC-adapter of the second embodiment of the present invention shown in a state where a parallel-blade pins are in an extruded position.  
         [0031]    [0031]FIGS. 10A through 10D are a perspective view, a plan view, a front view and a side view of a plug configuration adapter of the second embodiment of the present invention.  
         [0032]    [0032]FIG. 11 is a schematic view showing an internal structure of the pin configuration adapter of the second embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    In the following, principles and embodiments of the present invention will be described with reference to the accompanying drawings.  
         [0034]    FIGS.  1  to  7  are diagrams used for explaining a pin configuration adapter for an AC-adapter (hereinafter referred to as a pin configuration adapter)  20  of a first embodiment the present invention. FIG. 1 is a diagram showing how the pin configuration adapter  20  is attached to an AC-adapter  10 . FIG. 2 is a perspective view of the AC adapter  10 . FIGS. 3A through 4C are diagrams showing the configuration of the AC-adapter  10 . FIGS. 5A through 5C are diagrams showing the structure of the pin-configuration adapter  20 . FIGS. 6A and 6B are diagrams showing how the pin-configuration adapter  20  is attached to the AC-adapter  10 .  
         [0035]    As shown in FIG. 1, in use, the pin configuration adapter  20  is attached to the AC-adapter  10 .  
         [0036]    Before describing the pin configuration adapter  20  in detail, an explanation will be made of the AC-adapter  10 . As shown in FIG. 2, the AC-adapter  10  generally includes an AC-adapter housing  11 , a rotatable plug body  12  and a cord  17 .  
         [0037]    The adapter housing  11  is a housing made of resin and includes a first housing half-body  11   a  and a second housing half-body  11   b . The housing half-bodies  11   a  and  11   b  are fixed together to form the AC-adapter housing  11 .  
         [0038]    Inside the AC-adapter housing  11 , there is provided a power transformer circuit (not shown) for converting an alternating current supplied from the rotatable plug body  12  to a direct current of a predetermined voltage.  
         [0039]    Also, a recess  15  is formed at a predetermined position of the AC-adapter housing  11 . The rotatable plug body  12  described below is provided in this recess  15 .  
         [0040]    Further, the AC-adapter housing  11  is provided with L-shaped engagement grooves  16   a  and  16   b . The L-shaped engagement grooves  16   a  and  16   b  are provided on the side walls  10   b  of the AC-adapter housing  11 .  
         [0041]    As shown in FIG. 1, the L-shaped engagement grooves  16   a ,  16   b  ( 16   b  is not shown in the figure) includes a first engagement groove part  16 c and a second engagement groove part  16   d , which is substantially perpendicular to the first engagement groove part  16   c . The second engagement groove part  16   d  is formed so as to extend substantially perpendicular to a direction of protrusion of parallel-blade pins  14 . Also, the second engagement groove part  16   d  is formed such that it also extends substantially perpendicular to a direction of axis of round pins  25  of the pin-configuration adapter  20 .  
         [0042]    The L-shaped engagement grooves  16   a  and  16   b  are formed at positions corresponding to side-protrusions  33   a  and  33   b . formed on the pinconfiguration adapter  20 . The side-protrusions  33   a  and  33   b . are provided to engage with the L-shaped engagement grooves  16   a  and  16   b.    
         [0043]    The AC-adapter housing  11  is provided with recessed parts  18   a  and  18   b . The recessed parts  18   a  and  18   b  are provided on an upper surface  10 C of the AC-adapter housing  11 . The recessed parts  18   a  and  18   b  are formed at positions corresponding to upper-protrusions  34   a  and  34   b  formed on the pin-configuration adapter  20 , which will be described later.  
         [0044]    The rotatable plug body  12  includes a base part  13  and parallel-blade pins  14 . The base part  13  is made of insulating resin and can be rotated about a rotational axis in a y-direction through an angle of approximately 90°. The parallel-blade pins  14  are formed in an integrated manner with the base part  13 , for example, by insert molding. Accordingly, when the rotatable plug body  12  rotates about the rotational axis, the parallel-blade pins  14  also rotate about the rotational axis in an integrated manner.  
         [0045]    In detail, the rotatable plug body  12  rotates through an angle of approximately 90° between a first position shown in FIGS. 2 through 4C, in which the parallel-blade pins  14  are accommodated in the recess  15 , and a second position in which the parallel-blade pins  14  are substantially perpendicular to the upper surface  10   a  of the AC-adapter housing  11   
         [0046]    Further, for safety reasons, the AC-adapter  10  of the present embodiment is configured as follows. When the rotational plug body  12  takes the first position, the parallel-blade pins  14  and the power supply converting circuit are disconnected. When the rotational plug body  12  takes the second position, that is to say only when using the AC-adapter  10 , the parallel-blade pins  14  and the power supply conversion circuit are connected.  
         [0047]    Now, the configuration of the pin configuration adapter  20  will be described with reference to FIGS. 5A through 5C.  
         [0048]    The pin configuration adapter  20  generally includes a pin configuration adapter housing  21  and round pins  25 .  
         [0049]    The pin configuration adapter housing  21  is formed of a first housing part  21   a , a second housing part  21   b  and a third housing part  21   c . The housing parts  21   a  through  21   c  are made by resin molding and in the present embodiment, formed in an integrated manner by molding.  
         [0050]    As shown in FIGS. 5A through 5C, the pin configuration adapter housing  21  is provided with a pair of round pins  25  protruding upwards from the upper surface  23 . The round pins  25  conforms the European (EU) standard for plugs. Also, the third housing part  21   c  is provided with an AC-adapter attaching part  22  whereto the AC-adapter  10  is attached. The AC-adapter attaching part  22  is provided with plug-insertion holes  30 . When the pin-configuration adapter  20  is attached to the AC-adapter, the parallel-blade pins  14  of the AC-adapter are inserted into the plug insertion holes  30 .  
         [0051]    The AC-adapter attaching part  22  is configured to fit with the AC-adapter  10 . In detail, the AC-adapter attaching part  22  is provided with side-protrusions  33   a ,  33   b  which engage with engagement grooves  16   a ,  16   b  and upper-protrusions  34   a ,  34   b  which engage with recessed parts  18   a ,  18   b . The side-protrusions  33   a ,  33   b . and the upper-protrusions  34   a ,  34   b  constitute a pin-configuration adapter engagement structure.  
         [0052]    As shown in FIGS. 5A through 5C, the side-protrusions  33   a  and  33   b  are formed on either sides of the front-end part of an inner surface of the AC-adapter attaching part  22 . The side-protrusions  33   a  and  33   b  are formed integral with the pin-configuration adapter housing  21 .  
         [0053]    Also, the side-protrusions  33   a  and  33   b  are formed at positions corresponding to positions of open parts  19  of the L-shaped engagement grooves  16   a  and  16   b  formed on the AC-adapter  10 .  
         [0054]    The upper-protrusions  34   a  and  34   b  are formed on an inner upper surface of the AC-adapter attaching part  22  in an integrated manner with the pin configuration adapter housing  21 . The upper-protrusions  34   a  and  34   b  are provided at positions corresponding to the recessed parts  18   a  and  18   b  formed on the AC adapter  10 .  
         [0055]    As shown in FIG. 1, the L-shaped engagement grooves  16   a  and  16   b  ( 16   b  is not shown in the figure) are formed such that the engagement groove parts  16   d  extend in a direction substantially perpendicular to the direction of an axis of the of round pins  25 . With such a configuration, the side-protrusions  33   a  and  33   b  for engagement grooves are prevented from slipping out from the L-shaped engagement grooves  16   a  and  16   b.    
         [0056]    The above-described plug insertion holes  30  are configured such that the side-protrusions  33   a  and  33   b  provided on the pin-configuration adapter  20  can move along the L-shaped engagement grooves  16   a  and  16   b  of the AC-adapter  10  when attaching the AC-adapter  10  to the pin-configuration adapter  20 .  
         [0057]    In the present embodiment, as shown in FIGS. 5A to  5 C, two recessed parts are formed on the inner upper surface of the AC-adapter attaching part  22 . However, the number of protrusion is not limited to two, but any number of protrusions may be provided on the inner upper surface of the AC-adapter.  
         [0058]    Referring now to FIG. 7, an internal structure of the pin configuration adapter housing  21  will be described.  
         [0059]    [0059]FIG. 7 is a schematic diagram showing the pin configuration adapter housing  21 . As shown in FIG. 7, the round pins  25  are fixed on the pin configuration adapter housing  21  for example by insert molding. The round pins  25  are configured such that connection parts  25 A are provided at ends of the round pins  25  in the pin configuration adapter housing  21 .  
         [0060]    Contacts  31  are provided inside the pin configuration adapter housing  21  on an inner upper surface at positions opposing the pin insertion holes  30 . The connection parts  25  formed on the round pins  25  and connection parts  31 A formed on the contacts  31  are electrically connected by connection wires  32 . Thus, an electrical connection is established between the round pins  25  and the contacts  31 .  
         [0061]    Thus, when the pin configuration adapter  20  is attached to the AC adapter  10  and the parallel-blade pins  14  engage with the contacts  31  via the pin insertion holes  30 , the parallel-blade pins  14  will be electrically connected with the round pins  25  via the connection wires  32 .  
         [0062]    Now, an operation of attaching the above-described pin configuration adapter  20  to the AC-adapter  10  will be described.  
         [0063]    In order to attach the pin configuration adapter  20  to the AC-adapter  10 , as shown in FIG. 1, the side-protrusions  33   a ,  33   b  ( 33   b  is not shown in the figure) of the pin-configuration adapter  20  is positioned against the open parts  19  of the engagement grooves  16   a  and  16   b  of the AC-adapter  10 . Then the pin configuration adapter  20  is moved along the x-axis until the side-protrusions  33   a  and  33   b  of the pin configuration adapter  20  touches wall parts  19   b  of the L-shaped engagement grooves  16   a  and  16   b . Then, the AC-adapter  10  is moved along the y-axis until the side-protrusions  33   a  and  33   b  of the pin configuration adapter  20  reaches end parts  19   c  of the L-shaped engagement grooves  16   a  and  16   b  of the AC-adapter  10 . Thus, the upper protrusion  34   a  and  34   b  of the pin configuration adapter  20  engage with engagement grooves  18   a  and  18   b  of the AC-adapter  10 . Accordingly, the pin configuration adapter  20  and the AC-adapter  10  are attached.  
         [0064]    In such a manner, the side-protrusions  33   a  and  33   b  of the pin configuration adapter  20  are guided to end parts of the L-shaped engagement grooves  16   a  and  16   b  of the AC-adapter  10 . Thus, the pin configuration adapter  20  can be easily attached to the AC-adapter  10 . It is to be noted that a direction in which the side-protrusions  33   a ,  33   b  of the pin configuration adapter  20  moves along the engagement grooves  16   a ,  16   b  of the AC-adapter  10  and a direction in which a force is applied while insertion and retraction from the power socket are perpendicular. Therefore, even if the pin configuration adapter  20  is inserted into and pulled out of the power supply outlet with the AC-adapter  10  being attached thereto, the pin configuration adapter  20  is prevented from being detached from the AC-adapter  10 . Accordingly, the pin configuration adapter  20  and the AC-adapter  10  can be attached in a secure manner.  
         [0065]    Also, since the upper protrusions  34   a  and  34   b  of the pin configuration adapter  20  engage with the recessed parts  18   a  and  18   b  of the AC-adapter  10 , the pin configuration adapter  20  is further prevented from being detached from the AC-adapter  10 . Accordingly, the pin configuration adapter  20  and the AC-adapter  10  can be attached in a more secure manner.  
         [0066]    With such an attaching operation, the parallel-blade pins  14  of the AC-adapter  10  and the plug insertions holes  30  formed in the AC-adapter attaching part  22  of the conversion plug  20  can be engaged accurately.  
         [0067]    With the pin configuration adapter  20  being attached to the AC-adapter  10 , the parallel-blade pins  14  are inserted into the pin-configuration adapter housing  21  of the pin configuration adapter  20  via the plug insertion holes  30 .  
         [0068]    In this manner, the parallel-blade pins  14  engage with and are electrically connected to the contacts  31  and further electrically connected to the round pins  25  via the connection wire  32 . Therefore, with the pin configuration adapter  20  being attached, the AC-adapter  10  can be used in those countries adopting the round pins  25  as the standard for pin configuration.  
         [0069]    In the following, a second embodiment of the present invention will be described.  
         [0070]    [0070]FIGS. 8 through 11 are diagrams used for explaining the second embodiment of the present invention.  
         [0071]    [0071]FIG. 8 is a perspective view showing how a pin configuration adapter  120  is attached to an AC-adapter  110  in accordance with a second embodiment of the present invention. FIGS. 9A through 9C are diagrams showing a structure of the AC-adapter  110  of the second embodiment of the present invention. FIGS. 10A through 10D are diagrams showing a plug configuration adapter  120  of the second embodiment of the present invention.  
         [0072]    As shown in FIG. 8, when in use, the pin configuration adapter  120  is attached to the AC-adapter. This is similar to the case of the first embodiment.  
         [0073]    Before explaining the pin configuration adapter  120 , the structure of the AC-adapter  110  will be described. Elements similar to those of the first embodiment are labeled using the same reference numerals and will not be explained in a further detail.  
         [0074]    As shown in FIGS. 8 through 9D, the AC-adapter  110  generally includes an AC-adapter housing  111 , a rotatable plug body  112  and a cord  117 . The adapter housing  111  includes a first housing half-body  111   a  and a second housing half-body  111   b.    
         [0075]    Inside the AC-adapter housing  111 , there is provided a power transformer circuit (not shown) for converting an alternating current supplied from the rotatable plug body  12  to a direct current of a predetermined voltage.  
         [0076]    On an upper surface  110   c  of the AC-adapter housing  111 , collar parts  141   a ,  141   b  are formed along the X 1 - and X 2 -directions. The collar parts  141   a  and  141   b  protrude outwardly. Also, with such collar parts  141   a  and  141   b  being provided, grooves  142   a  and  142   b  are formed on upper side edges of the AC-adapter housing  111 .  
         [0077]    The grooves  142   a  and  142   b  extend along entire length of the side edges of the AC-adapter housing  111  (X 1 - and X 2 -direction in the Figure).  
         [0078]    In the present embodiment, the grooves  142   a  and  142   b  are configured to extend along entire length of the side edges of the AC-adapter housing  111 . However, the length of the grooves  142   a  and  142   b  may be shorter than the entire length of the side edges of the AC-adapter housing  111 . Also, as shown in FIG. 9, in the present embodiment, the grooves  142   a  and  142   b  are provided on the upper side surface of the AC-adapter housing  111 . However, the grooves  142   a  and  142   b  may be provided at any position as long as they are on the side surface of the AC-adapter housing  111 .  
         [0079]    As shown in FIG. 8, the grooves  142   a  and  142   b  extend substantially parallel to the direction in which the parallel-blade pins  114  of the AC-adapter  110  extend. The grooves  142   a  and  142   b  extend in a direction substantially perpendicular to the direction of axis of the round pins  125  of the pin configuration adapter  120 .  
         [0080]    The collar parts  141   a ,  141   b  and the grooves  142   a ,  142   b  formed on the AC-adapter housing  111  constitute an engagement structure  140 .  
         [0081]    The AC-adapter engagement structure  140  is configured to correspond to an engagement structure of the pin configuration adapter  120  described later.  
         [0082]    The AC-adapter housing  111  is provided with L-shape engagement grooves  16   a  and  16   b  as has been described in relation to the first embodiment. The L-shaped engagement grooves  16   a  and  16   b  are formed on side surfaces of the AC-adapter housing  111 . Also, as shown in FIG. 9D, the recessed parts  18   a  and  18   b  described in the first embodiment are formed on an upper surface  110   c  of the AC-adapter housing  111 . If the L-shaped engagement grooves  16   a ,  16   b  and the recessed parts  18   a ,  18   b  are formed on the AC-adapter housing  111 , this AC-adapter  110  can also be used for the pin configuration adapter  20  described in the first embodiment.  
         [0083]    In the following, the structure of the pin configuration adapter  120  will be described with reference to FIG. 10.  
         [0084]    The pin configuration adapter  120  generally includes a pin configuration adapter housing  121 , round pins  125  and an AC-adapter attaching part  122 .  
         [0085]    As shown in FIG. 10, the pin configuration adapter housing  121  is formed of a first housing part  121   a , a second housing part  121   b  and a third housing part  121   c . The housing parts  121   a  through  21   c  are made by resin molding and in the present embodiment, formed in an integrated manner by molding.  
         [0086]    The pin configuration adapter housing  121  is provided with a pair of round pins  125  protruding upwards from the upper surface  123  of the first housing part  121   a.    
         [0087]    The AC-adapter attaching part  122  is provided with plug-insertion holes  130 . When the pin-configuration adapter  120  is attached to the AC-adapter  110 , the parallel-blade pins  114  of the AC-adapter  110  are inserted into the plug insertion holes  130 . In the second embodiment, the plug insertion holes  130  may be formed with a length sufficient for receiving the parallel-blade pins  114 . This differs from the first embodiment of the present invention.  
         [0088]    On an upper surface  124  of the third housing part  121   c , a supporting part  126  for supporting the first housing part  121   a  is formed.  
         [0089]    Wall parts  145   a  and  145   b  are formed on either sides of the supporting part  126  along the X 1 -, X 2 -directions in FIGS. 10A and 10D. The wall parts  145   a  and  145   b  constitute a side surface of the adapter attaching part.  
         [0090]    Also, the wall parts  145   a  and  145   b  are provided with engagement collars  143   a  and  143   b . which protrude inwardly. The engagement collars  143   a  and  143   b . also extend along the X 1 -, X 2 -directions in FIGS. 10A and 10D in a similar manner to the walls  145   a  and  145   b.    
         [0091]    The engagement collars  143   a  and  143   b . are configured to correspond to the shape of the grooves  142   a  and  142   b  of the AC-adapter  110  and extend in a direction substantially perpendicular to the direction of axis of the round pins  125 .  
         [0092]    As shown in FIG. 8, guide grooves  144   a  and  144   b  are formed so as to mate with the engagement collar  143   a , respectively. The engagement collars  143   a ,  143   b  and the guide grooves  144   a ,  144   b  formed on the wall parts  145   a ,  145   b  constitute the pin-configuration adapter engagement structure  143 . The pin-configuration adapter engagement structure  143  is configured to mate with the above-described AC-adapter engagement structure  140 .  
         [0093]    Also, in the present embodiment, as shown in FIG. 8, the engagement collars  143   a ,  143   b  of the pin configuration adapter  120  are formed at positions corresponding to the engagement grooves  142   a ,  142   b  of the AC-adapter housing  111 . However, the engagement collars  143   a  and  143   b  may be provided at any position on the inner surface of the adapter attaching part  122  as long as they correspond to the engagement grooves  142   a ,  142   b  of the AC-adapter housing  111 .  
         [0094]    In the following, an internal structure of the pin-configuration adapter housing  121  will be described with reference to FIG. 11.  
         [0095]    [0095]FIG. 11 is a schematic diagram showing an internal structure of the pin-configuration adapter housing  121 . As shown in FIG. 11, the round pins  125  are fixed on the pin configuration adapter housing  121  for example by insert molding. The round pins  125  are configured such that connection parts  125 A are provided at ends of the round pins  125  in a first pin configuration adapter housing  121   a . Also, inside the second housing part  121   b  opposing the plug insertion holes  130  formed in the adapter attaching part  122  and the third housing part  121   c , contacts  131  are provided as shown by dashed lines. The connection parts  125 A formed on the round pins  125  and the contacts  131  are electrically connected by connection wires  132 .  
         [0096]    Thus, an electrical connection is established between the round pins  125  and the contacts  131 . Thrs, when the pin configuration adapter  120  is attached to the AC adapter  110  and the parallel-blade pins  114  engage with the contacts  131  via the pin insertion holes  130 , the parallel-blade pins  114  will be electrically connected with the round pins  125  via the connection wires  132 .  
         [0097]    Now, an operation of attaching the above-described pin configuration adapter  120  to the AC-adapter  110  will be described.  
         [0098]    In order to attach the pin configuration adapter  120  to the AC-adapter  110 , as shown in FIG. 8, the AC-adapter engaging structure  140  of the AC-adapter  10  and the pin-configuration adapter engaging structure  143  of the pin-configuration adapter  120  are positioned and the AC-adapter  110  is moved in the X-direction.  
         [0099]    In detail, the engagement collars  143   a ,  143   b  of the pin configuration adapter  120  are inserted into the guide grooves  142   a ,  142   b , respectively of the AC-adapter  110 . Thus, the AC-adapter engagement structure  140  and the pin configuration adapter engagement structure  143  are engaged.  
         [0100]    Accordingly, the pin configuration adapter  120  and the AC-adapter  110  are attached. The engagement collars  143   a ,  143   b  of the pin configuration adapter  120  are guided along the engagement grooves  142   a ,  142   b  of the AC-adapter  110 . Thus, the pin configuration adapter  120  can be easily attached to the AC-adapter  110 . It is to be noted that a direction in which the engagement collars  143   a ,  143   b  of the pin configuration adapter  20  detaches from the engagement grooves  142   a ,  142   b  of the AC-adapter  110  and a direction in which a force is applied while insertion and retraction from the power socket are perpendicular. Therefore, even if the pin configuration adapter  120  is inserted into and pulled out of the power supply outlet with the AC-adapter  110  being attached thereto, the pin configuration adapter  120  is prevented from being detached from the AC-adapter  110 . Accordingly, the pin configuration adapter  120  and the AC-adapter  110  can be attached in a secure manner.  
         [0101]    With such an attaching operation, the parallel-blade pins  114  of the AC-adapter  110  and the plug insertions holes  130  formed in the AC-adapter attaching part  122  can be engaged accurately.  
         [0102]    With the pin configuration adapter  120  being attached to the AC-adapter  110 , the parallel-blade pins  114  are inserted into the pin-configuration adapter housing  121  of the pin configuration adapter  120  via the plug insertion holes  130 .  
         [0103]    In this manner, the parallel-blade pins  114  engage with and are electrically connected to the contacts  131  and further electrically connected to the round pins  125  via the connection wire  132 .  
         [0104]    Also, if the L-shaped engagement grooves  16   a ,  16 B and the recessed parts  18   a ,  18   b  are further provided on the AC-adapter housing  111 , this AC-adapter  110  can be used for the pin configuration plug  20  described in the first embodiment.  
         [0105]    Therefore, with the pin configuration adapter  120  being attached, the AC-adapter  110  can be used in those countries adopting the round pins  125  as the standard for pin configuration.  
         [0106]    It is to be noted that the above embodiment has been described using the round pins  25  and  125  as an example of the pins provided on the pin configuration adapter  20  and  120 . However, the pin configuration adapter  20  and  120  may be altered to configurations conforming the standards for various countries by providing pins of various types on the pin configuration adapter housing  21  and  121 . For example, the pins of the pin configuration adapter can be configured as non-parallel blade pins and 3-terminal pins.  
         [0107]    The present invention has been described with reference to preferred embodiments. However, the present invention is not limited to these embodiments, and variations and modifications may be made without departing from the scope of the present invention.  
         [0108]    The present application is based on Japanese priority application No. 2001-59274 filed on Mar. 2, 2001, the entire contents of which are hereby incorporated by reference.