Patent Publication Number: US-8123539-B2

Title: Connector

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to connectors, and more particularly to a connector that is suited for supplying power, and to a combination of male and female connectors. 
     2. Description of the Related Art 
     Generally, an electronic apparatus needs to receive power from a power supply in order to perform an operation. Usually, the power from the power supply is supplied to the electronic apparatus via connectors. The connectors that are used to make the electrical connection include a male connector and a female connector that are designed to mate. Examples of such connectors are proposed in Japanese Laid-Open Patent Publications No. 5-82208 and No. 2003-31310, for example. 
     On the other hand, as a countermeasure against global warming, power transmissions in local areas using high DC voltages are being studied. According to such power transmissions, the power loss during the voltage transformation and power transmission is small, and it is unnecessary to increase the cross sectional size of cables. In information processing apparatuses, such as servers, which have a large power consumption, it is desirable to make the power supply according to such a power transmission. 
     But when supplying power to the electronic apparatus, there may be undesirable effects on the human body and on the electronic parts if the power is supplied in the form of a high voltage. 
     In addition, in the case of the electronic apparatus, such as the server, which receives the power in the form of the high voltage, the setup or maintenance of the electronic apparatus is attended to by a service person or maintenance person. Hence, as a safety measure, the connectors used in such an electronic apparatus for making the necessary electrical connections are configured differently from the connectors that are generally used for receiving power from a commercial power supply outlet. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a general object of one aspect of the present invention to provide a novel and useful connector and a combination of male and female connectors, in which the problems described above are suppressed. 
     Another and more specific object of one aspect of the present invention is to provide a connector and a combination of male and female connectors, which can safely transmit power in a form of a high voltage. 
     According to one aspect of the present invention, there is provided a female connector for supplying received power, comprising a recess configured to receive a male connector; a plurality of terminals including power terminals for supplying the power; a locking mechanism configured to lock the male connector that is inserted into the recess in a mated state in response to insertion of the male connector into the recess; and a switching mechanism configured to supply the received power to the power terminals in an ON state and to insulate the power terminals from the received power in an OFF state, wherein the switching mechanism is permitted to make a transition to the ON state only when the locking mechanism is locking the male connector in the mated state. 
     According to another aspect of the present invention, there is provided a combination of a male connector and a female connector, said combination comprising a male connector comprising first terminals; and a female connector comprising a recess configured to receive the male connector; a plurality of second terminals including power terminals for supplying received power; a locking mechanism configured to lock the male connector that is inserted into the recess in a mated state in response to insertion of the male connector into the recess; and a switching mechanism configured to supply the received power to the power terminals in an ON state and to insulate the power terminals from the received power in an OFF state, wherein the switching mechanism is permitted to make a transition to the ON state only when the locking mechanism is locking the male connector in the mated state. 
     Other objects and further features of various aspects the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram for explaining electrical connections of connectors in a first embodiment of the present invention; 
         FIGS. 2A ,  2 B and  2 C are diagrams, in partial transparency, showing a structure of a female connector in the first embodiment; 
         FIGS. 3A ,  3 B,  3 C,  3 D, and  3 E are diagrams showing a structure of a male connector in the first embodiment; 
         FIG. 4  is a side view, in partial transparency, showing the connectors of the first embodiment in a mated state; 
         FIGS. 5A ,  5 B,  5 C and  5 D are diagrams for explaining an operation of an abutting switch of the female connector in the first embodiment; 
         FIG. 6  is a diagram showing a structure of a power supply system using the connectors of the first embodiment; 
         FIG. 7  is a perspective view showing a Power Distribution Unit (PDU) using the connectors of the first embodiment; 
         FIGS. 8A ,  8 B,  8 C and  8 D are diagrams showing a structure of a male connector of a second embodiment of the present invention; and 
         FIG. 9  is a side view, in partial transparency, showing the connectors of the second embodiment in a mated state. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description will be given of embodiments of a connector and a combination of male and female connectors according to the present invention, by referring to the drawings. 
       FIG. 1  is a diagram for explaining electrical connections or electrical couplings of connectors in a first embodiment of the present invention. 
     In this embodiment, the combination of male and female connectors include a male connector  10  and a female connector  20 . The male connector  10  is connected to an information processing apparatus  40 , such as a server and a computer, via a power cable  15 . The male connector  10  includes two power plug terminals  11  and  12  for receiving power, and a ground plug terminal  13  for grounding. 
     On the other hand, the female connector  20  is connected to a high-voltage power supply  50  for supplying power. The female connector  20  includes power jack terminals  21  and  22  which correspond to the power plug terminals  11  and  12 , and a ground jack terminal  23  which corresponds to the ground plug terminal  13 . The female connector  20  further includes two control switches  31  and  32 . For example, the control switches  31  and  32  are respectively formed by a leaf spring switch or the like which permits a current to flow when a moving contact makes contact with a fixed contact. An abutting switch  90  controls the connection state of the control switches  31  and  32 . When the abutting switch  90  is pushed, the moving contact makes contact with the fixed contact in each of the control switches  31  and  32 . 
     A first fixed contact of the control switch  31 , which is connected to the moving contact, is connected to a positive polarity output of the high-voltage power supply  50 . A second fixed contact of the control switch  31  is connected to the power jack terminal  21 . A first fixed contact of the control switch  32 , which is connected to the moving contact, is connected to a negative polarity output of the high-voltage power supply  50 . A second fixed contact of the control switch  32  is connected to the power jack terminal  22 . 
     Of course, in each of the control switches  31  and  32 , the moving contact may be fixed to the second fixed contact so that the moving contact is controlled to make contact with the first fixed contact. 
     When the moving contact makes contact with the second fixed contact in each of the control switches  31  and  32 , the power is supplied to the power jack terminals  21  and  22  of the female connector  20 . In this state, when the male connector  10  is connected to the female connector  20 , the power is supplied from the power jack terminals  21  and  22  of the female connector  20  to the corresponding power plug terminals  11  and  12  of the male connector  10 , and the power is consequently supplied to the information processing apparatus  40  via the male connector  10  and the power cable  15 . 
     In this embodiment, the control switches  31  and  32  are provided with respect to the power jack terminals  21  and  22  in order to improve safety. If the high voltage supplied from the high-voltage power supply  50  exceeds 48 V, and particularly if a DC high-voltage of 200 V or higher is supplied from the high-voltage power supply  50 , there may be undesirable effects on the human body when a person touches the power jack terminals  21  and  22  which is supplying the high-voltage. For example, the high-voltage supplied from the high-voltage power supply  50  may be a DC high-voltage of 400 V. But by providing the abutting switch  90  which controls the connection state of the control switches  31  and  32 , it is possible to control the timing when the power jack terminals  21  and  22  are to supply the high-voltage. 
       FIGS. 2A ,  2 B and  2 C are diagrams, in partial transparency, showing a structure of the female connector  20  in the first embodiment.  FIG. 2A  is a top view of the female connector  20 .  FIG. 2B  is a front view, in partial transparency, showing the female connector  20  viewed in a direction A in  FIG. 2A , and  FIG. 2C  is a side view, in partial transparency, showing the female connector  20  viewed in a direction B in  FIG. 2A . 
     The female connector  20  in this embodiment has a recess  25  into which the male connector  10  can be inserted, as will be described later. The power jack terminals  21  and  22  and the ground jack terminals  23  are provided at the bottom of the recess  25 , that is, at a bottom surface defining the bottom of the recess  25 . As described above, the first contact of the control switch  31  is connected to the high-voltage power supply  50 , and the second contact of the control switch  31  is connected to the power jack terminal  21 . On the other hand, the first contact of the control switch  32  is connected to the high-voltage power supply  50 , and the second contact of the control switch  32  is connected to the power jack terminal  22 . 
     A releasable lock  80  is provided on a side surface of the recess  25  (or a skirt portion forming the recess  25 ) of the female connector  20 . The releasable lock  80  has a claw part  81  provided on one end thereof, and a circular projection  82  provided on the other end thereof. The releasable lock  80  has a rotary shaft  83  provided in a central part thereof, and the releasable lock  80  is linked to the female connector  20  via the rotary shaft  83 . Hence, the releasable lock  80  is pivotable about the rotary shaft  83 . A compression spring  84  is loaded on the rotary shaft  83 , so that the circular projection  82  projects into the recess  25  of the female connector  20  from the side surface of the recess  25  in a state where the male connector  10  is not inserted into the recess  25  of the female connector  20 . In addition, a stopper  85  is provided on the other end of the releasable lock  80  provided with the circular projection  82 . The stopper  85  is formed by an L-shaped projecting part extending approximately parallel to the rotary shaft  83 . A more detailed description of the stopper  85  will be given later in the specification. 
     The releasable lock  80 , the claw part  81 , the circular projection  82 , the rotary shaft  83 , the compression spring  84 , and the stopper  85  form a locking mechanism. 
     Next, a description will be given of the male connector  10  of this embodiment, by referring to  FIGS. 3A through 3E .  FIGS. 3A ,  3 B,  3 C,  3 D, and  3 E are diagrams showing a structure of the male connector  10  in the first embodiment.  FIG. 3A  shows a bottom view of the male connector  10 ,  FIG. 3B  shows a front view of the male connector  10 , and  FIG. 3C  shows a top view of the male connector  10 . 
     The male connector  10  of this embodiment has a flange  16 , and the power plug terminals  11  and  12  and the ground plug terminal  13  are provided on the flange  16 . A main body of the male connector  10  is connected to the power cable  15 , and the main body has a locking part  17 . A portion of the main body is removed along a direction in which the male connector  10  is inserted into the recess  25  of the female connector  20 , in order to form the locking part  17 . As will be described later, the flange  16  has a function of turning the releasable lock  80  of the female connector  20  in order to lock the male connector  10  and the female connector  20  in a mated state, and a function of improving insulation with respect to the human body when a person inserts the male connector  10  into the female connector  20  or removes the male connector  10  from the female connector  20 . 
     The structure of the locking part  17  of the male connector  10  in this embodiment is not limited to that shown in  FIGS. 3B and 3C , and may have a modified structure shown in  FIGS. 3D and 3F , for example.  FIG. 3D  shows a front view of the male connector  10  having the locking part  17  having the modified structure, and  FIG. 3E  is a side view of the male connector  10  shown in  FIG. 3D . 
     In this embodiment, it is assumed for the sake of convenience that the power plug terminals  11  and  12  and the ground plug terminal  13  have a cylindrical shape, however, the plug terminals  11  through  13  may have other suitable shapes, such as a blade shape. Of course, the plug terminals  11  through  13  do not need to have identical shapes, and at least one of the plug terminals  11  through  13  may have a shape different from that of the other two of the plug terminals  11  through  13 . In addition, the cross sectional area of the plug terminals  11  and  12  may be different from that of the plug terminal  13 . For example, the cross sectional area of the plug terminals  11  and  12  may be larger than that of the plug terminal  13 . The different plug shape and/or size can prevent the male connector  10  from being inserted into the female connector  20  in an incorrect orientation. 
     Next, a description will be given of the male connector  10  and the female connector  20  in the mated state, by referring to  FIG. 4 .  FIG. 4  is a side view, in partial transparency, showing the connectors  10  and  20  of the first embodiment in the mated state. 
     In the mated state where the male connector  10  is inserted into the recess  25  of the female connector  20 , the power plug terminals  11  and  12  are inserted into and make contact with the corresponding power jack terminals  21  and  22 , and the ground plug terminal  13  is inserted into and make contact with the corresponding ground jack terminal  23 . In addition, in this mated state, a side surface of the flange  16  of the male connector  10  makes contact with and pushes the circular projection  82  of the releasable lock  80  that is provided in the female connector  20 . Due to the pushing force applied on the circular projection  82 , the releasable lock  80  pivots about the rotary shaft  83  from a state indicated by a dotted line to a state indicated by a solid line in  FIG. 4 , and the claw part  81  of the releasable lock  80  locks a portion of the flange  16  where the locking part  17  of the male connector  10  is formed. Accordingly, the locking engagement of the claw part  81  and the flange  16  enables the mated state of the male connector  10  and the female connector  20  to be maintained. In this mated state, the releasable lock  80  is pivotable about the rotary shaft  83 , and the male connector  10  may be pulled and removed from the female connector  20 . When removing the male connector  10  from the female connector  20 , the releasable lock  80  pivots about the rotary shaft  83  by the force of the compression spring  84 , so that the releasable lock  80  returns to the original state before the insertion of the male connector  10  into the female connector  20  when the male connector  10  is disconnected from the female connector  20 . 
     In a state where the male connector  10  is not yet completely removed (that is, pulled out completely) from the recess  25  of the female connector  20 , the power plug terminals  11  and  12  of the male connector  10  are still in contact with the corresponding power jack terminals  21  and  22  of the female connector  20 , and the ground plug terminal  13  of the male connector  10  is still in contact with the corresponding ground jack terminal  23  of the female connector  20 . But as will be described later, the moving contact is not connected to the second fixed contact in each of the control switches  31  and  32  (that is, the control switches  31  and  32  are in an open state or an OFF state) by the action of the abutting switch  90 , to thereby prevent the power from being supplied from the high-voltage power supply  50  to the power plug terminals  11  and  12  of the male connector  10  via the power jack terminals  21  and  22  of the female connector  20 . In other words, the control switches  31  and  32  in the OFF state insulate the power jack terminals  21  and  22  from the power supplied from the high-voltage power supply  50 . 
     Next, a description will be given of the abutting switch  90  which controls the supply of power from the high-voltage power supply  50 , by referring to  FIGS. 5A ,  5 B,  5 C and  5 D.  FIGS. 5A ,  5 B,  5 C and  5 D are diagrams for explaining the abutting switch  90  of the female connector  20  in the first embodiment.  FIG. 5A  is a side view, showing the abutting switch  90  in partial transparency, in a state before the male connector  10  is inserted into the recess  25  of the female connector  20 , that is, before the abutting switch  90  is pushed.  FIG. 5B  is a front view, in partial transparency, showing a portion of the abutting switch  90  viewed in a direction C in  FIG. 5A .  FIG. 5C  is a side view, showing the abutting switch  90  in partial transparency, in the mated state where the male connector  10  and the female connector  20  are connected and the abutting switch  90  is pushed.  FIG. 5D  is a front view, in partial transparency, showing a portion of the abutting switch  90  viewed in the direction C in  FIG. 5C . 
     The abutting switch  90  may be formed by a push-button switch or the like. The abutting switch  90  is maintained in an ON state when pushed once, and returns to the original OFF state when pushed again. 
     As shown in  FIGS. 5A and 5B , the abutting switch  90  has a contact pushing shaft  91 , a cutout  92  adapted to allow passing of the stopper  85  of the releasable lock  80 , a stopper holding part  93  for holding the stopper  85  of the releasable lock  80  in a state where the abutting switch  90  is pushed, a compression spring  94  for returning the abutting switch  90  from the pushed state to the original state, and a knock rotation part  95 . The knock rotation part  95  rotates every time the abutting switch  90  is pushed, and alternately puts the abutting switch  90  to the ON state and the OFF state. In the OFF state where the abutting switch  90  is not pushed, the moving contact does not make contact with the second contact in each of the control switches  31  and  32 , that is, the control switches are in the open state or the OFF state. 
     The control switches  31  and  32 , the abutting switch  90 , the contact pushing shaft  91 , the cutout  92 , the stopper holding part  93 , the compression spring  94 , and the knock rotation part  95  form a switching mechanism which is linked to the locking mechanism described above. The switching mechanism in an ON state supplies the power from the high-voltage power supply  50  to the power jack terminals  21  and  22  of the female connector  20 , but this ON state is only permitted in a state where the locking mechanism is locking the male connector  10  in the mated state with respect to the female connector  20 . The switching mechanism makes a transition to the ON state when the abutting switch  90  is pushed manually by a person. The switching mechanism in an OFF state insulates the power jack terminals  21  and  22  of the female connector  20  from the power from the high-voltage power supply  50 . Further, the locking mechanism is prohibited from releasing the lock with respect to the male connector  10  (in the mated state) in the ON state of the switching mechanism. 
     When the male connector  10  is inserted into the recess  25  of the female connector  20  as shown in  FIG. 4 , the circular projection  81  of the releasable lock  80  is pushed by the flange  16  of the male connector  10 , and the releasable lock  80  pivots about the rotary shaft  83 . By this pivoting action of the releasable lock  80 , the stopper  85  can pass through the cutout  92  of the abutting switch  90 . 
     Thereafter, as shown in  FIGS. 5C and 5D , the abutting switch  90  is pushed in the mated state where the male connector  10  is inserted into the recess  25  of the female connector  20 , in order to put the abutting switch  90  to an ON state from an OFF state. By pushing the abutting switch  90 , the pushing force causes the moving contact to make contact with the second contact in each of the control switches  31  and  32 . In other words, the control switches  31  and  32  are put into a closed state or an ON state. As a result, the power from the high-voltage power supply  50  is supplied to the power jack terminals  21  and  22  of the female connector  20 , and is transmitted to the corresponding power plug terminals  11  and  12  of the male connector  10 . 
     On the other hand, when the male connector  10  and the female connector  20  are mated, the releasable lock  80  pivots and the claw part  81  locks the flange  16  of the male connector  10  as described above in conjunction with  FIG. 4 . In this state, even if the abutting switch  90  is pushed, the stopper  85  of the releasable lock  80  is held by the stopper holding part  93  of the abutting switch  90  and the releasable lock  80  cannot pivot about the rotary shaft  83 . In this state where the releasable lock  80  is prevented from pivoting, the claw part  81  of the releasable lock  80  in the female connector  20  locks the flange  16  of the male connector  10 , and the male connector  10  cannot be removed from the female connector  20 . Consequently, the mated state of the male connector  10  and the female connector  20  is maintained. 
     However, when the abutting switch  90  is pushed again in this embodiment, the knock rotation part  95  rotates, and the abutting switch  90  returns to the original OFF state by the force of the compression spring  94 . In the OFF state of the abutting switch  90 , the stopper  85  of the releasable lock  80  is movable, and consequently, the male connector  10  is removable (that is, disconnectable) from the female connector  20 . 
     Next, a description will be given of a structure of a power supply system using the connectors of this embodiment, by referring to  FIG. 6 .  FIG. 6  is a diagram showing the structure of the power supply system using the connectors  10  and  20  of the first embodiment. 
     The power supply system shown in  FIG. 6  inputs the power from a commercial power supply  70 , such as an AC voltage of 100V or 200V, to an AC-to-DC (AC/DC) converter  51  of the high-voltage power supply  50 . The AC/DC converter  51  converts the AC voltage of 100 V or 200 V into a DC voltage of 400 V, for example. The high-voltage power supply  50  is provided with a backup battery  52  for copying with a power failure situation or the like. This backup battery  52  stores the DC power output of the AC/DC converter  51 . The high-voltage power supply  50  is connected to the female connector  20  of this embodiment via a cable. Hence, the power from the high-voltage power supply  50 , that is, the DC voltage of 400 V, is supplied from the female connector  20 . 
     On the other hand, the male connector  10  of this embodiment mates with the female connector  20 . The male connector  10  is connected to the information processing apparatus  40  via the power cable  15 , in order to supply the power from the high-voltage power supply  50  to the information processing apparatus  40 . In this example, the information processing apparatus  40  includes a DC-to-DC (DC/DC) converter  41  and a Central Processing Unit (CPU)  42 . The DC/DC converter  41  converts the DC voltage of 400 V into a relatively low DC voltage with which electronic parts, including the CPU  42 , is able to perform an operation. 
     The power loss of the power supply system shown in  FIG. 6  is small, because the conversion of the AC power from the commercial power supply  70  into the DC power is only carried out once. In addition, when transmitting the high DC voltage of 400 V, it is unnecessary to make the cross sectional size of the power cable relatively large. Furthermore, the DC voltage output from the AC/DC converter  51  of the high-voltage power supply  40  can be supplied to the backup battery  52  to charge (that is, accumulate charge in) the backup battery  52 . The provision of the backup battery  52  which may be charged by the DC power output of the AC/DC converter  51  enables continued operation using the power supply system even if a power failure of the commercial power supply  70  occurs. 
     Next, a description will be given of a Power Distribution Unit (PDU) using the connectors of this embodiment, by referring to  FIG. 7 .  FIG. 7  is a perspective view showing the PDU using the connectors  10  and  20  of the first embodiment. 
     The DC voltage of 400 V which is supplied from the high-voltage power supply  50  shown in  FIG. 6  is input to a distribution board  170  shown in  FIG. 7 . The distribution board  170  distributes the power to each of a plurality of PDUs  30 . Each PDU  30  has a plurality of female connectors  20 , and is capable of supplying power, namely, the DC voltage of 400 V, via each female connector  20 . On the other hand, a server rack  45  accommodates a plurality of information processing apparatuses  40 , such as servers and computers, and each information processing apparatus  40  is connected via a power cable  15  to a male connector  10  for receiving power. By mating the male connector  10  to the female connector  20  of the PDU  30 , the DC voltage of 400 V may be supplied to the information processing apparatus  40  via the male connector  10  and the power cable  15 . 
     Next, a description will be given of a second embodiment of the present invention. In this second embodiment, the male connector is provided with a pin for pivoting the releasable lock. 
       FIGS. 8A ,  8 B,  8 C and  8 D are diagrams showing a structure of a male connector of the second embodiment of the present invention.  FIG. 8A  shows a bottom view of a male connector  110  of this embodiment,  FIG. 8B  shows a front view of the male connector  110 , and  FIG. 5C  shows a top view of the male connector  110 . 
     In this embodiment, the male connector  110  has flange  116 . Power plug terminals  111  and  112 , a ground plug terminal  113 , and a pin  114  are provided on the flange  116 . The pin  114  extends parallel to the plug terminals  111  through  113 . A main body of the male connector  110  is connected to a power cable  115 , and the main body has a locking part  117 . A portion of the main body is removed along a direction in which the male connector  110  is inserted with respect to a female connector  120 , in order to form the locking part  117 . As will be described later, the flange  116  has a function of turning a releasable lock  180  of the female connector  120  in order to lock the male connector  110  and the female connector  120  in a mated state, and a function of improving insulation with respect to the human body when a person inserts the male connector  110  into the female connector  120  or removes the male connector  110  from the female connector  120 . 
     The structure of the male connector  110  in this embodiment is not limited to that shown in  FIGS. 8A through 8C , and may have a modified structure shown in  FIG. 8D , for example. In the modified structure shown in  FIG. 8D , a partition  119  is provided on the flange  116  in order to partition the regions in which the terminals  111  through  113  and the pin  114  are provided. The partition  119  enables the sliding distance of the terminals  111  through  113  to increase with respect to the corresponding terminals  121  through  123  of the female connector  120 , while positively preventing unwanted short-circuiting of adjacent terminals. In this particular example, the partition  119  is formed by X-shaped walls in the top view. However, the partition  119  may be formed by grooves in the flange  116 , and the grooves may also have an X-shape in the top view. In this case, the depth of the grooves forming the partition  119  enables the sliding distance of the terminals  111  through  113  to increase with respect to the corresponding terminals  121  through  123  of the female connector  120 , while positively preventing unwanted short-circuiting of adjacent terminals. 
     In this embodiment, it is assumed for the sake of convenience that the power plug terminals  111  and  112  and the ground plug terminal  113  have a cylindrical shape, however, the plug terminals  111  through  113  may have other suitable shapes, such as a blade shape. Of course, the plug terminals  111  through  113  do not need to have identical shapes, and at least one of the plug terminals  111  through  113  may have a shape different from that of the other two of the plug terminals  111  through  113 . In addition, the cross sectional area of the plug terminals  111  and  112  may be different from that of the plug terminal  113 . For example, the cross sectional area of the plug terminals  111  and  112  may be larger than that of the plug terminal  113 . The different plug shape and/or size can prevent the male connector  110  from being inserted into the female connector  120  in an incorrect orientation. 
     Next, a description will be given of the male connector  110  and the female connector  120  of this embodiment in a mated state, by referring to  FIG. 9 .  FIG. 9  is a side view, in partial transparency, showing the connectors  110  and  120  of the second embodiment in the mated state. In this second embodiment, those parts that are the same as those corresponding parts of the first embodiment are designated by the same reference numerals, and an illustration and description thereof will be omitted. 
     In the mated state of the male connector  110  and the female connector  120 , the plug terminals  111  through  113  of the male connector  110  make contact with the corresponding jack terminals  121  through  123  of the female connector  120 . In addition, when mating the male connector  110  and the female connector  120 , the pin  114  of the male connector  110  makes contact with and pushes against a circular projection  182  of a releasable lock  180  that is provided in the female connector  120 . Hence, the releasable lock  180  pivots about a rotary shaft  183  from a state indicated by a dotted line to a state indicated by a solid line, and a claw part  181  of the releasable lock  180  locks a portion of the flange  116  where the locking part  117  of the male connector  110  is formed. Accordingly, the locking engagement of the claw part  181  and the flange  116  enables the mated state of the male connector  110  and the female connector  120  to be maintained. In this mated state, the releasable lock  180  is pivotable about the rotary shaft  183 , and the male connector  110  may be pulled and removed from the female connector  120 . When removing the male connector  110  from the female connector  120 , the releasable lock  180  pivots about the rotary shaft  183  by the force of a compression spring  184 , so that the releasable lock  180  returns to the original state before the insertion of the male connector  110  into the female connector  120  when the male connector  110  is disconnected from the female connector  120 . 
     In a state where the male connector  110  is not yet completely removed (that is, pulled out completely) from the female connector  120 , the power plug terminals  111  and  112  of the male connector  110  are still in contact with the corresponding power jack terminals  121  and  122  of the female connector  120 , and the ground plug terminal  113  of the male connector  110  is still in contact with the corresponding ground jack terminal  123  of the female connector  120 . However, the moving contact is not connected to the second fixed contact in each of the control switches  31  and  32  (not shown) by the action of the abutting switch  90  (not shown), to thereby prevent the power from being supplied from the high-voltage power supply  50  (not shown) to the power plug terminals  111  and  112  of the male connector  110  via the power jack terminals  121  and  122  of the female connector  120 . 
     Except for the mechanisms associated with the pin  114 , this embodiment is otherwise basically the same as the first embodiment described above. 
     The embodiments described above use the combination of the male and female connectors to supply the DC voltage of 400 V, for example. However, the combination of the male and female connectors are suited for supplying any DC voltage, because unlike the AC voltage, the DC voltage does not have a frequency safe to the human body. 
     From the point of view of preventing undesirable effects on the human body, the DC voltage is normally set to 48 V or lower since it may be regarded that the effects of electric shock on the human body is virtually negligible for DC voltages of 48 V or lower. The effects on the human body are large for DC voltages exceeding 48 V, and it may be regarded dangerous for DC voltages of 200 V or higher. 
     The male connector, the female connector, and the combination of the male and female connectors according to the embodiments described above can improve the safety by improving the insulation with respect to the human body when a person inserts the male connector into the female connector or removes the male connector  10  from the female connector. The effects of improving the safety are notable for DC voltages exceeding 48 V, and particularly notable for DC voltages of 200 V or higher. 
     This application claims the benefit of a Japanese Patent Application No. 2008-196923 filed on Jul. 30, 2008, in the Japanese Patent Office, the disclosure of which is hereby incorporated by reference. 
     Further, the present invention is not limited to these embodiments, but various variations and modifications may be made without departing from the scope of the present invention.