Abstract:
An incorrect-insertion-prevention structure of a connector which prevents a first connector from being incorrectly inserted into a space formed within a second connector to be fitted to the first connector, wherein the first connector includes at least one first magnet, a bottom surface or a side surface at an insertion end to be inserted into the second connector, wherein the second connector includes: a shutter rotatably and pivotally supported by a rotating shaft to open and close an inlet of the space, and a shutter-rotation-prevention unit rotatably and pivotally supported by a supporting shaft in parallel to the rotating shaft of the shutter to prevent the shutter from being rotated in an opening direction, and wherein the shutter-rotation-prevention unit shutter-rotation-prevention unit includes: at least one engaging member facing a rotation end of the shutter in a closed state to prevent the shutter from being moved in the opening direction.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2013-225689 filed on Oct. 30, 2013, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to an incorrect insertion prevention structure of a connector and the connector. 
       BACKGROUND 
       [0003]    In a case where signals are transmitted and received between two units, male and female connectors with electrodes corresponding to the number of signals have conventionally been used. Meanwhile, when one device is provided with a plurality of connectors, signal transmission is not accurately carried out when matching connectors are not connected to each other. Therefore, there is an incorrect fitting prevention connector in which key pins are provided at one or more portions of a terminal portion of one side connector, and holes, into which the key pins are inserted, are formed at the other side connector, so that the one side connector and the other side connector are not fitted to each other when the positions of the key pins do not correspond to the positions of the holes. In the incorrect fitting prevention connector as described above, since key pins are formed at empty pin positions of a connector, there is a limitation in the types of accurately fittable connectors. In addition, since the fitting is mechanical, key pins may be damaged when an incorrect connector is inserted. 
         [0004]    In contrast, there is a connector which employs a fitting structure using an external shape of a connector without key pins. However, in this type of connector, since a difference in a physical shape is used, the combination of connectors is limited and only several different types may be coped with. Further, there is a problem in that a manufacturing cost is expensive because the shapes of the connectors are different from each other. 
         [0005]    Therefore, Patent Document 1 discloses a connector in which magnets are provided in corresponding positions of a connector socket and a connector plug, and the corresponding magnets are attracted to each other only in matching connectors so as to connect the connectors to each other. Patent Document 2 discloses a connector in which connector pins themselves are formed of magnets, and connection is made only when polarities of magnets at seven positions are completely opposite to polarities of corresponding magnets. 
         [0006]    [Patent Document 1] Japanese Laid-Open Patent Publication No. 2009-231114. 
         [0007]    [Patent Document 2] Japanese Laid-Open Patent Publication No. 2004-247387. 
       SUMMARY 
       [0008]    However, in the connector disclosed in Patent Document 1, the magnets are small. Thus, even when an incorrect connector is inserted and a corresponding magnet is repulsive, forced insertion may be made due to a weak repulsive force. In addition, the connector disclosed in Patent Document 2 has a problem in that a cost is increased because the number of used magnets is large, and the shape is complicated. Thus, what is required is an incorrect insertion prevention structure of a connector and the connector with the structure in which a plurality of connectors are identifiable to prevent incorrect insertion, connector shapes are identical, and the connector pins are not broken even if enforced insertion is made. Hereinafter, the term “incorrect insertion prevention structure of a connector” will be referred to as “incorrect insertion prevention structure” for the convenience of description. 
         [0009]    According to an aspect of the embodiments, an incorrect-insertion-prevention structure of a connector which prevents a first connector from being incorrectly inserted into a space formed within a second connector to be fitted to the first connector, wherein the first connector includes at least one first magnet, a bottom surface or a side surface at an insertion end to be inserted into the second connector, wherein the second connector includes: a shutter rotatably and pivotally supported by a rotating shaft to open and close an inlet of the space, and a shutter-rotation-prevention unit rotatably and pivotally supported by a supporting shaft in parallel to the rotating shaft of the shutter to prevent the shutter from being rotated in an opening direction, and wherein the shutter-rotation-prevention unit shutter-rotation-prevention unit includes: at least one engaging member facing a rotation end of the shutter in a closed state to prevent the shutter from being moved in the opening direction. 
         [0010]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0011]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1A  is a cross-sectional view illustrating a state where female and male connectors provided with an incorrect insertion prevention structure of a first exemplary embodiment of the present disclosure before they are fitted to each other; 
           [0013]      FIG. 1B  is a bottom planview illustrating the female connector illustrated in  FIG. 1A ; 
           [0014]      FIG. 1C  is a cross-sectional view taken along line C-C in  FIG. 1A ; 
           [0015]      FIG. 1D  is a perspective view illustrating a single structure of a shutter illustrated in  FIG. 1A ; 
           [0016]      FIG. 1E  is a perspective view illustrating a shutter rotation prevention unit illustrated in  FIG. 1A , and a permanent magnet attached on the shutter rotation prevention unit; 
           [0017]      FIG. 2A  is a cross-sectional view illustrating a state where the female connector is abutted on the shutter of the male connector illustrated in  FIG. 1A ; 
           [0018]      FIG. 2B  is a cross-sectional view illustrating a state where the female connector is inserted into the space of the male connector while the shutter rotation prevention unit is moved from the state illustrated in  FIG. 2A ; 
           [0019]      FIG. 2C  is a cross-sectional view illustrating a state where the female and male connectors are fitted to each other while the female connector is further inserted from the state illustrated in  FIG. 2B ; 
           [0020]      FIG. 3  is an explanatory view illustrating types of connectors, and combinations of fittable connectors, in a case where two permanent magnets are attached to each of female and male connectors; 
           [0021]      FIG. 4A  is a side elevational view illustrating female and male connectors provided with an incorrect insertion prevention structure of a second exemplary embodiment of the present disclosure; 
           [0022]      FIG. 4B  is a view illustrating a part of a rotation end of a shutter and a front end portion of an engaging member as illustrated in  FIG. 4A  in an enlarged scale; 
           [0023]      FIG. 5A  is a top plan view of a female connector provided with an incorrect insertion prevention structure of a third exemplary embodiment of the present disclosure; 
           [0024]      FIG. 5B  is a side elevational view illustrating the female connector illustrated in  FIG. 5A ; 
           [0025]      FIG. 5C  is a rear elevational view illustrating the female connector illustrated in  FIG. 5A ; 
           [0026]      FIG. 6A  is a top plan view illustrating a male connector corresponding to the female connector illustrated in  FIG. 5A ; 
           [0027]      FIG. 6B  is a cross-sectional view taken along line A-A in  FIG. 6A ; 
           [0028]      FIG. 6C  is a cross-sectional view taken along line B-B in  FIG. 6B ; 
           [0029]      FIG. 7A  is a top plan view illustrating a state where the female connector illustrated in  FIG. 5A  is fitted to the male connector illustrated in  FIG. 6A ; 
           [0030]      FIG. 7B  is a cross-sectional view taken along line A′-A′ of  FIG. 7A ; 
           [0031]      FIG. 7C  is a rear elevational view illustrating the female and male connectors illustrated in  FIG. 7A ; 
           [0032]      FIG. 8A  is a top plan view illustrating a permanent magnet attached to the bottom surface of a female connector; 
           [0033]      FIG. 8B  is a front elevational view illustrating the permanent magnet; 
           [0034]      FIG. 8C  is a side elevational view illustrating the permanent magnet; 
           [0035]      FIG. 9A  is a top plan view illustrating the engaging member and the permanent magnet formed in the male connector; 
           [0036]      FIG. 9B  is a front elevational view illustrating the engaging member and the permanent magnet; 
           [0037]      FIG. 9C  is a side elevational view illustrating the engaging member and the permanent magnet; 
           [0038]      FIG. 10A  is a top plan view illustrating the state where female and male connectors provided with an incorrect insertion prevention structure of a fourth exemplary embodiment of the present disclosure are fitted to each other; 
           [0039]      FIG. 10B  is a side elevational view of the female connector illustrated in  FIG. 10A ; 
           [0040]      FIG. 10C  is a rear elevational view of the female connector illustrated in  FIG. 10A ; 
           [0041]      FIG. 11  is a side elevational view of female and male connectors provided with an incorrect insertion prevention structure of a fifth exemplary embodiment of the present disclosure; and 
           [0042]      FIG. 12  is a perspective view illustrating a unit shelf provided with an incorrect insertion prevention structure of a sixth exemplary embodiment of the present disclosure, and power supply units and HDD units to be mounted in the unit shelf. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0043]    Hereinafter, detailed descriptions will be made on specific exemplary embodiments of an incorrect insertion prevention structure and a connector provided with the structure according to the present disclosure with reference to accompanying drawings. Meanwhile, the incorrect insertion prevention structure of the present disclosure is provided at both the female connector and the male connector, and is not formed at only any one of the connectors. 
         [0044]      FIG. 1A  illustrates a state where a female connector  1  (a first connector) and a male connector  2  (a second connector) provided with an incorrect insertion prevention structure of a first exemplary embodiment of the present disclosure before they are fitted to each other. The female connector  1  is inserted into a space  21  of the male connector  2  to be coupled with the male connector  2 . The incorrect insertion prevention structure includes magnets  15  which are provided in the female connector  1 , and a shutter  23 , engaging members  24 , magnets  25 , and springs  26  which are provided in the male connector  2 . As for the magnets  15  and the magnets  25 , for example, permanent magnets may be used. 
         [0045]    First, the structure of the female connector  1  will be described with reference to  FIGS. 1A and 1B . A plurality of sockets  12  configured to receive pins provided at the male connector side is provided on the front surface of the housing of the female connector  1 . A cable  14  connected to the sockets  12  is provided on a rear surface  16 . In addition, two permanent magnets  15  are attached on a bottom surface  13 . Each of the permanent magnets  15  has a rod shape, in which one end portion is formed as an N pole and the other end portion is formed as an S pole. Accordingly, when the number of the permanent magnets  15  is two, four types of female connectors  1  may be prepared depending on which one of the N pole and the S pole of each of the permanent magnets  15  is located at the front surface side. 
         [0046]    Subsequently, a structure of the male connector  2  will be described with reference to  FIGS. 1A ,  1 C,  1 D and  1 E. A space  21  is formed in the housing  20  of the male connector  2 , and a plurality of pins  22  to be inserted into the sockets  12  of the female connector  1  is provided in the innermost portion of the space  21 .  FIG. 1A  does not illustrates a terminal connected to the pins  22  to transmit signals to the outside of the housing  20 . A shutter  23  configured to open and close the inlet of the space  21  is provided at the inlet of the space  21 . The shutter  23  is pivotally supported by rotating shafts  23 A provided on the upper portion of the space  21  to shut the inlet of the space  21 , and, upon being pressed, to be rotated and open the inlet. When the shutter  23  rotates and moves into the space  21 , a rotation end  23 E of the shutter  23  is not abutted on the pins  22 . 
         [0047]    Meanwhile, a guide member  20 G is provided at the inlet  20 A of the space  21  of the housing  20  to guide the female connector  1  into the space  21  of the male connector  2 . The female connector  1  slides on the guide member  20 G, comes in contact with the shutter  23 , pushes and opens the shutter  23 , and then enters the inside of the space  21 . A shutter rotation prevention unit  28  is provided at a portion (a bottom surface) positioned lower than the top surface of the guide member  20 G in the space  21  so as to prevent the shutter  23  from being rotated into the space  21 . The shutter rotation prevention unit  28  includes an engaging member  24 , a permanent magnet  25 , and a spring  26 . 
         [0048]    The engaging member  24  is configured to be rotatable by rotating shafts  24 A which are provided at the bottom surface side of the housing  20  to be in parallel to the rotating shafts  23 A of the shutter  23 . The permanent magnet  25  is attached on the rear surface of the engaging member  24 . A spring  26  is provided on the bottom surface of the housing  20  to support the permanent magnet  25  so that one end of the engaging member  24  is located on the rear surface of the rotation end  23 E of the shutter  23 . 
         [0049]      FIG. 1D  illustrates a structure of the shutter  23 , and  FIG. 1E  illustrates the permanent magnet  25  attached on the rear surface of the engaging member  24 . The rotating shafts  24 A are provided at both lateral sides of the center of the engaging member  24 , and the full length of the permanent magnet  25  attached on the rear surface of the engaging member  24  is longer than the full length of the engaging member  24 . In the present exemplary embodiment, the lengths of the permanent magnet  25  protruding from both ends of the engaging member  24  are the same. Accordingly, as illustrated in  FIG. 1A , in a state where the rear surface of the permanent magnet  25  is supported by the spring  26 , and the one end of the engaging member  24  is located on the rear surface of the rotation end  23 E of the shutter  23 , the front end portion of the permanent magnet  25  is exposed to the outside of the shutter  23  through the outside of the rotation end  23 E of the shutter  23 . 
         [0050]    The positions of the front end portions of the permanent magnets  25  exposed to the outside of the shutter  23  are substantially the same as that of the female connector  1  when the female connector  1  comes close to a position where the female connector  1  is abutted on the shutter  23 . The female connector side permanent magnets  15  and the male connector side permanent magnets  25  are spaced apart from each other by a distance that allows each permanent magnet not to be affected by other than a permanent magnet positioned to face the permanent magnet in the counterpart connector. The widthwise distance between the permanent magnets  15  or  25  in each connector is set to be larger than the vertical distance between the permanent magnets  15  and the permanent magnets  25  of both connectors when both side connectors come closest to each other so that the permanent magnets  15  or  25  in each connector are not affected by each other. 
         [0051]    The number of the shutter rotation prevention units  28  equals to the number of the permanent magnets  15  provided in the female connector  1 . The width of each permanent magnet  25  in the shutter rotation prevention unit  28  equals to the width of each permanent magnet  15  in the female connector  1 . Further, the positions of the front end portions of the permanent magnets  25  exposed to the outside of the shutter  23  correspond to the positions of the permanent magnets  15  provided on the bottom surface of the female connector  1  when the female connector  1  comes close to the male connector  2 . The magnetic pole of each permanent magnet  25  exposed to the outside of the shutter  23  is an N pole or an S pole. 
         [0052]    When the permanent magnets  15  provided in the female connector  1  and the permanent magnets  25  provided in the male connector  2  have the same polarities when the female connector  1  is inserted into the male connector  2 , a biasing force acts on the springs  26  from a repulsive force acting between the permanent magnets  15  and the permanent magnets  25 . The springs  26  have a biasing force enough to be bent by the biasing force acting on the springs  26 . Accordingly, when the permanent magnets  15  and the permanent magnets  25  have the same polarities, the permanent magnets  25  moves to the bottom side of the housing  20  by the repulsive force to rotate the engaging member  24  around the rotating shafts  24 A. As a result, one end of each engaging member  24  is moved from the rear surface position of the rotation end  23 E of the shutter  23 . 
         [0053]    Hereinafter, descriptions will be made on a connector identification operation of the incorrect insertion prevention structure when the female connector is not correct for the male connector (does not correspond to the male connector) when the female connector  1  configured as illustrated in  FIGS. 1A and 1B  is inserted into the male connector  2  configured as illustrated in  FIGS. 1A ,  1 C to  1 E. When the female connector does not correspond to the male connector, the polarities of the permanent magnets  15  provided in the female connector  1  do not coincide with the polarities of the permanent magnets  25  exposed to the outside of the shutter  23  of the male connector  2 . 
         [0054]      FIG. 2A  illustrates a case where the female connector  1  intended to be inserted into the male connector  2  is not correct. In this case, the polarity of the permanent magnet  15  provided in the female connector  1  does not coincide with the polarity of the permanent magnet  25  provided in the male connector. For example, in a case where both polarities of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , are N poles, and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are S poles, when the female connector  1  comes close to the male connector  2 , the permanent magnets  15  and the permanent magnets  25  attract each other. This may also be applied to a case where both magnetic polarities of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , are S poles, and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are N poles. 
         [0055]    As a result, each permanent magnet  25  maintains its position taken until now, and thus one end of each engaging member  24  is still located at the rear surface of the rotation end  23 E of the shutter  23 . In this state, even when the shutter  23  is pressed by the front surface  11  of the female connector  1  to insert the female connector  1  into the male connector  2 , the shutter  23  is not opened because the rear surface side of the rotation end  23 E of the shutter  23  is abutted on one end of the engaging member  24 . Accordingly, the female connector  1  cannot be inserted into the male connector  2  and thus incorrect insertion can be prevented. 
         [0056]    The above described example corresponds to a case where both magnetic polarities of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , are N poles (or S poles), and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are S poles (or N poles). Meanwhile, there is a case where one side magnetic polarity of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , is an N pole, and the other side polarity is an S pole, and one side polarity of the permanent magnets  25  exposed to the outside of the shutter  23  is an S pole, and the other side polarity is an N pole. In this case, there are three combinations of polarities of the permanent magnets  15  and the permanent magnets  25  facing each other when the female connector  1  comes close to the male connector  2 ; (A) facing polarities at both sides are different from each other, (B) facing polarities at only one side are different from each other, and (C) facing polarities at both sides are the same. 
         [0057]    In the case (A), the two permanent magnets  15  and  25  attract each other. Thus, each permanent magnet  25  maintains its position taken until now, and thus one end of each engaging member  24  is still located on the rear surface of the rotation end  23 E of the shutter  23 . Accordingly, even when the shutter  23  is pressed by the front surface  11  of the female connector  1 , the shutter  23  is not opened. Accordingly, the female connector  1  cannot be inserted into the male connector  2  and thus, incorrect insertion can be prevented. 
         [0058]    In the case (B), between the two pairs of permanent magnets  15  and  25 , the magnets of the pair having different polarities attract each other, and the magnets of the pair having the same polarities repel each other. Accordingly, at the side where the polarity of the permanent magnet  25  is different from that of the permanent magnet  15 , the permanent magnet  25  maintains its position taken until now, but at the side where the polarity of the permanent magnet  25  is the same as that of the permanent magnet  15 , the permanent magnet  25  is moved and one end of the engaging member  24  is moved to a position retracted from the rear surface of the rotation end  23 E of the shutter  23 . However, at the side where the polarity of the permanent magnet  25  is different from that of the permanent magnet  15 , the permanent magnet  25  is not moved, and one end of the engaging member  24  is still located on the rear surface of the rotation end  23 E of the shutter  23 . Thus, even when the shutter  23  is pressed by the front surface  11  of the female connector  1 , the shutter  23  is not opened. Accordingly, the female connector  1  cannot be inserted into the male connector  2  and incorrect insertion can be prevented. The case (C) will be described later. 
         [0059]    Hereinafter, descriptions will be made on a connector identification operation of the incorrect insertion prevention structure in a case where the female connector  1  configured as illustrated in  FIGS. 1A and 1B  is inserted into the male connector  2  configured as illustrated in  FIGS. 1A ,  1 C to  1 E, when the female connector is correct for the male connector (corresponds to the male connector). When the female connector corresponds to the male connector, the polarities of the permanent magnets  15  provided in the female connector  1  coincide with the polarities of the permanent magnets  25  exposed to the outside of the shutter  23  of the male connector  2 . 
         [0060]      FIG. 2B  illustrates a case where the female connector  1  intended to be inserted into the male connector  2  is correct. In this case, the polarities of the permanent magnets  15  provided in the female connector  1  coincide with the polarities of the permanent magnets  25  provided in the male connector. For example, in a case where both polarities of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , are N poles, and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are N poles, when the female connector  1  comes close to the male connector  2 , the permanent magnets  15  and the permanent magnets  25  repel each other. This may also be applied to a case where both magnetic polarities of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , are S poles, and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are S poles. 
         [0061]    As a result, each permanent magnet  25  moves from the position taken until now so that one end of each engaging member  24  is moved to a position where the one end does not face the rear surface of the rotation end  23 E of the shutter  23 . In this state, when the shutter  23  is pressed by the front surface  11  of the female connector  1  to insert the female connector  1  into the male connector  2 , the shutter  23  is opened because the rear surface side of the rotation end  23 E of the shutter  23  is not abutted on the one end of the engaging member  24 . Accordingly, the female connector  1  may be moved into the space  21  of the male connector  2  while rotating the shutter  23 . When the female connector  1  is inserted into the male connector  2  as it is, the female connector  1  and the male connector  2  are fitted to each other because the pins  22  of the male connector  2  are inserted into the sockets  12  of the female connector  1  as illustrated in  FIG. 2B . 
         [0062]    The above described example corresponds to a case where both magnetic polarities of the two permanent magnets  15  provided in the female connector  1 , at the front side of the housing  10 , are N poles (or S poles), and both polarities of the permanent magnets  25  exposed to the outside of the shutter  23  are N poles (or S poles). Meanwhile, when one side magnetic polarity of the two permanent magnets  15  provided in the female connector  1 , at the front surface side of the housing  10 , is an N pole, and the other side polarity is an S pole, and one side polarity of the permanent magnets  25  exposed to the outside of the shutter  23  is an S pole, and the other side polarity is an N pole, the above described three combinations may be made. Because the cases (A) and (B) have already been described, the case (C) will be described below. 
         [0063]    In the case (C), the two pairs of permanent magnets  15  and  25  repel each other. Thus, each permanent magnet  25  moves from the position taken until now so that one end of each engaging member  24  is moved to a position where the one end does not face the rear surface of the rotation end  23 E of the shutter  23 . In this state, when the shutter  23  is pressed by the front surface  11  of the female connector  1  to insert the female connector  1  into the male connector  2 , the rear surface side of the rotation end  23 E of the shutter  23  is not abutted on the one end of the engaging member  24 , and the shutter  23  is opened. Accordingly, the female connector  1  may be moved into the space  21  of the male connector  2  while rotating the shutter  23 . When the female connector  1  is inserted into the male connector  2  as it is, the female connector  1  and the male connector  2  are fitted to each other, because the pins  22  of the male connector  2  are inserted into the sockets  12  of the female connector  1  as illustrated in  FIG. 2B . 
         [0064]      FIG. 3  is an explanatory view illustrating types of connectors, and combinations of fittable connectors, in a case where the two permanent magnets  15  are attached to the female connector  1 , and the two permanent magnets  25  are attached to the male connector  2 . When the two permanent magnets  15  are attached to the female connector  1 , four types of female connectors  1 A,  1 B,  1 C and  1 D may be provided according to the combinations of the magnetic poles of the permanent magnets  15 . Likewise, when the two permanent magnets  25  are attached to the male connector  2 , four types of male connectors  2 A,  2 B,  2 C and  2 D may be provided according to the combinations of the magnetic poles of the permanent magnets  25 . The male connectors  2 A,  2 B,  2 C and  2 D are mounted on a substrate  3  in the present exemplary embodiment. 
         [0065]    As described above, a combination which enables the female connector  1  to be fitted to the male connector  2  is that the polarities of the permanent magnets  15  attached to the female connector  1  completely coincide with polarities of the permanent magnets  25  attached to the male connector  2 . Thus, the female connector  1 A may be fitted only to the male connector  2 B. Likewise, the female connector  1 B may be fitted only to the male connector  2 A, the female connector  1 C may be fitted only to the male connector  2 D, and the female connector  1 D may be fitted only to the male connector  2 C. In this manner, when the two permanent magnets are attached to each female connector  1  and each male connector  2 , four types of connectors may be identified to prevent incorrect insertion. 
         [0066]      FIG. 4A  illustrates the state where female and male connectors provided with an incorrect insertion prevention structure of a second exemplary embodiment of the present disclosure just before they are fitted to each other. In the second exemplary embodiment, some elements of the incorrect insertion prevention structure which are the same as those in the first exemplary embodiment are given the same reference numerals in the drawings, and detailed descriptions thereof will be omitted. In the incorrect insertion prevention structure of the second exemplary embodiment, an engaging projection  23 P is formed on the rotation end  23 E of the shutter  23 , and at the same time, an engaging projection  24 P is also formed on the front end portion of the engaging member  24  of the shutter rotation prevention unit  28 .  FIG. 4B  is a view illustrating a part of the rotation end  23 E of the shutter  23  and the front end portion of the engaging member  24  as illustrated in  FIG. 4A  in an enlarged scale. In a case where the engaging projection  23 P is formed on the rotation end  23 E of the shutter  23 , and the engaging projection  24 P is formed on the front end portion of the engaging member  24 , when the shutter  23  is rotated while the engaging member  24  is not moved, the engaging projection  24 P is engaged with the engaging projection  23 P, thereby securely suppressing rotation. 
         [0067]      FIG. 9A  is a top plan view illustrating the engaging member  24  and the permanent magnet  25  provided in the male connector  2  with the incorrect insertion prevention structure of the second exemplary embodiment,  FIG. 9B  is a front elevational view illustrating the engaging member  24  and the permanent magnet  25 , and  FIG. 9C  is a side elevational view illustrating the engaging member  24  and the permanent magnet  25 . The engaging member  24  and the permanent magnet  25  are bonded to each other, and the permanent magnet  25  is formed in a rod shape and is longer than the engaging member  24 . The method of bonding the engaging member  24  to the permanent magnet  25  is not particularly limited. The lengths from the rotating shaft  24 A to both ends of the engaging member  24  are the same, and the lengths from the rotating shaft  24 A to both ends of the permanent magnet  25  are the same. The clamping projections  24 P are formed at both ends of the engaging member  24 . Accordingly, regardless of which pole side (an N pole side or an S pole side) of the permanent magnet  25  is placed at the shutter  23  side, the pair of the engaging member  24  and the permanent magnet  25  stacked as illustrated in  FIGS. 9A and 9B  may be commonly used. 
         [0068]    Meanwhile, in the incorrect insertion prevention structure of the second exemplary embodiment, a coil spring  27  attached to the rotating shaft  23 A of the shutter  23  is illustrated. The coil spring  27  is configured to fix the shutter  23  to the inlet of the space  21 . When the shutter  23  is pressed from the outside in a state where the engaging member  24  is moved, the coil spring  27  is rotated together with the shutter  23  and provides a biasing force to return the shutter  23  to its original position. The coil spring  27  is also provided in the incorrect insertion prevention structure of the first exemplary embodiment which has been described with reference to  FIGS. 1A to 2C . 
         [0069]    In the exemplary embodiment illustrated in  FIG. 4A , a permanent magnet  15  is fitted into the bottom surface  13  of the housing  10  of the female connector  1  by mounting protrusions  15 P.  FIGS. 8A to 8C  illustrate a top plan view, a side elevational view, and a front elevational view of a permanent magnet  15  formed with the mounting protrusions  15 P. The mounting surface portions of the both side ends of the permanent magnet  15  of the present exemplary embodiment are chamfered. The mounting protrusions  15 P may be made of a resin, and may be embedded in the permanent magnet  15 . A flat permanent magnet  15  may be adhered to the bottom surface  13  of the housing  10  of the female connector  1  by an adhesive. A resin cover may cover the surroundings of a permanent magnet  15 , and a mounting protrusion  15 P may be formed integrally with the cover. 
         [0070]      FIG. 5A  is a top plan view illustrating the female connector  1  provided with the incorrect insertion prevention structure of the third exemplary embodiment of the present disclosure,  FIG. 5B  is a side elevational view illustrating the female connector  1  illustrated in  FIG. 5A , and  FIG. 5C  is a rear elevational view illustrating the female connector  1  illustrated in  FIG. 5A .  FIG. 6A  is a top plan view illustrating the male connector  2  corresponding to the female connector  1  illustrated in  FIG. 5A ,  FIG. 6B  is a cross-sectional view taken along line A-A in  FIG. 6A , and  FIG. 6C  is a cross-sectional view taken along line B-B in  FIG. 6B . In the third exemplary embodiment, some elements of the incorrect insertion prevention structure which are the same as those in the first and second exemplary embodiments are given the same reference numerals in the drawings, and detailed descriptions thereof will be omitted. 
         [0071]    In the incorrect insertion prevention structure of the third exemplary embodiment, the housing  10  of the female connector  1  is divided into a fitting portion  10 A at the front surface  11  side, and a removal portion  10 B at the rear surface  16  side. Sockets  12  are provided on the front surface  11  of the fitting portion  10 A, and two permanent magnets  15  are provided on the bottom surface  13 . A removal arm  17  is provided on one side surface of the removal portion  10 B, and an engaging projection  17 P is formed in the middle of the removal arm  17 . A notch  10 R is formed on the rear surface  16  side surface of the removal portion  10 B to allow the removal arm  17  to be moved. The removal arm  17  may be formed to be integrally with the housing  10  made of a resin. Meanwhile, in  FIG. 5C , the cable  14  is not illustrated. 
         [0072]    An engaging recess  20 R configured to receive the engaging projection  17 P of the removal arm  17  provided in the female connector  1  is formed in the vicinity of the inlet  20 A of the housing  20  of the male connector  2 . The shutter  23  provided in the space  21  within the housing  20  of the male connector  2  and the shutter rotation prevention unit  28  of the shutter  23  have the same structures as those in the incorrect insertion prevention structure of the first exemplary embodiment which has been described with reference to  FIGS. 1A to 2C . 
         [0073]      FIG. 7A  is a top plan view illustrating the state where the female connector  1  illustrated in  FIG. 5A  is fitted to the male connector  2  illustrated in  FIG. 6A ,  FIG. 7B  is a cross-sectional view taken along line A′-A′ in  FIG. 7A , and  FIG. 7C  is a rear elevational view illustrating the state where the female and male connectors  1  and  2  illustrated in  FIG. 7A  are fitted to each other. In a state where the female connector  1  is fitted to the male connector  2 , the engaging projection  17 P formed on the removal arm  17  is received in the engaging recess  20 R formed in the vicinity of the inlet  20 A of the housing  20 , and thus, the female connector  1  is not separated from the male connector  2 . In a state where the female connector  1  is fitted to the male connector  2 , the shutter  23  is located at the ceiling portion of the housing  20 , and the permanent magnet  25  faces the permanent magnet  15  provided in the female connector  1  while biasing the spring  26 . 
         [0074]    When the female connector  1  is detached from the male connector  2 , the portion indicated by arrow F-F in  FIG. 7A  is gripped with fingers to move the free end of the removal arm  17  into the notch  10 R of the housing  10 . Then, the engaging projection  17 P escapes from the engaging recess  20 R of the housing  20 . Thus, in this state, the female connector  1  may be pulled out from the male connector  2 . When the female connector  1  is detached from the male connector  2 , the shutter  23  is returned to a position where the shutter  23  shuts the inlet  20 A by a coil spring (not illustrated), and the permanent magnet  25  of the shutter rotation prevention unit  28  is biased by the spring  26  so that the end portion of the engaging member  24  is returned to a position where the rotation of the shutter  23  is prevented. 
         [0075]      FIG. 10A  is a top plan view illustrating the state where a female connector  1  and a male connector  2  provided with an incorrect insertion prevention structure of a fourth exemplary embodiment of the present disclosure are fitted to each other.  FIG. 10B  is a side elevational view illustrating the state where the female connector  1  and the male connector  2  illustrated in  FIG. 10A  are fitted to each other, and  FIG. 10C  is a rear elevational view illustrating the state where the female connector  1  and the male connector  2  illustrated in  FIG. 10A  are fitted to each other. The structures of the female connector  1  and the male connector  2  provided with the incorrect insertion prevention structure of the fourth exemplary embodiment are basically the same as those of the female connector  1  and the male connector  2  provided with the incorrect insertion prevention structure of the third exemplary embodiment which has been described with reference to  FIGS. 5A to 7C . Accordingly,  FIG. 10A  corresponds to  FIG. 7A ,  FIG. 10B  corresponds to  FIG. 7B , and  FIG. 10C  corresponds to  FIG. 7C . 
         [0076]    The female connector  1  and the male connector  2  provided with the incorrect insertion prevention structure of the fourth exemplary embodiment are different from the female connector  1  and the male connector  2  provided with the incorrect insertion prevention structure of the third exemplary embodiment in terms of the number of permanent magnets  15  and  25  provided in the female connector  1  and the male connector  2 . In the incorrect insertion prevention structure of the third exemplary embodiment, each of the number of the permanent magnets  15  and the number of the permanent magnet  25 , which are respectively provided in the female connector  1  and the male connector  2 , is two. Meanwhile, in the incorrect insertion prevention structure of the fourth exemplary embodiment, four permanent magnets  15  are provided on the bottom surface of the housing  10  of the female connector  1 . In addition, four permanent magnets  25  are provided in the bottom portion of the space  21  of the housing  20  of the male connector  2  at positions which correspond to the four permanent magnets  15  provided in the female connector  1 , respectively. 
         [0077]    As described above, when four permanent magnets  15  are provided on the bottom surface of the housing  10  of the female connector  1 , and four permanent magnets  25  are provided in the bottom portion of the space  21  of the housing  20  of the male connector  2 , 16 types of the female connectors  1  and the male connectors  2  are present. When the female connector  1  and the male connector  2  provided with the incorrect insertion prevention structure of the fourth exemplary embodiment are fitted to each other, the polarities of the four permanent magnets  15  have to completely coincide with the polarities of the four permanent magnets  25 . 
         [0078]      FIG. 11  is a side elevational view illustrating the state where a female connector  1  and a male connector  2  provided with an incorrect insertion prevention structure of a fifth exemplary embodiment of the present disclosure are fitted to each other. In the incorrect insertion prevention structure of the first to fourth exemplary embodiments, the rotating shaft  23 A of the shutter  23  is provided in the upper portion of the space  21  within the housing  20  of the male connector  2 , and the shutter rotation prevention unit  28  is provided in the lower portion. Meanwhile, the incorrect insertion prevention structure of the fifth exemplary embodiment is different from that of the first to fourth exemplary embodiments in that the rotating shaft  23 A of the shutter  23  is provided in the lower portion of the space  21  within the housing  20  of the male connector  2 , and the shutter rotation prevention unit  28  is provided in the upper portion. Accordingly, in the female connector  1 , the permanent magnet  15  is provided on the upper surface of the housing  10 . 
         [0079]    The structures of the shutter  23  and the shutter rotation prevention unit  28  at the male connector  2  side and the structure of the permanent magnet  15  at the female connector  1  side in the incorrect insertion prevention structure in the fifth exemplary embodiment are the same as those in the first to fourth exemplary embodiments. Thus, some elements which are the same as those in the first to fourth exemplary embodiments are given the same reference numerals in drawings, and detailed descriptions thereof will be omitted. As described above, in the incorrect insertion prevention structure of the present disclosure, the shutter  23  and the shutter rotation prevention unit  28  at the male connector  2  side may be provided on any surfaces of the space  21  as long as they are provided on facing surfaces. 
         [0080]      FIG. 12  illustrates a unit shelf  4  provided with an incorrect insertion prevention structure of a sixth exemplary embodiment of the present disclosure, and two power supply units P1 and P2 and two HDD units H1 and H2 to be mounted in the unit shelf  4 . It is assumed that four slots S1, S2, S3 and S4 are provided in the unit shelf  4 , and the power supply unit P1 is mounted in the slot S1, the HDD unit H1 is mounted in the slot S2, the HDD unit H2 is mounted in the slot S3, and the power supply unit P2 is mounted in the slot S4. When the connectors provided with the incorrect insertion prevention structure of the present disclosure are used in the power supply units P1 and P2, and the HDD units H1 and H2, the power supply units P1 and P2 and the HDD units H1 and H2 cannot be fitted to connectors unless the polarities of the connectors coincide with the connectors of the power supply units P1 and P2 and the HDD units H1 and H2. Accordingly, the two power supply units P1 and P2 and the two HDD units H1 and H2 are mounted in the unit shelf  4  without concern about incorrect insertion. 
         [0081]    As described above, according to the present disclosure, a plurality of connectors having structures which are not fittable with the same structure may be prepared. Thus, an incorrect insertion prevention structure may be established without a burden on a connector terminal portion. In addition, since a magnetic force of a permanent magnet is used, the incorrect insertion prevention structure may be structurally simple, and may be simply set so that occurrence of, for example, a rearrangement, may be coped with. 
         [0082]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment(s) of the present invention has (have) been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.