Patent Publication Number: US-8123544-B2

Title: Electrical connector assembly adapted to withstand rotational movement

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT International Application No. PCT/JP2009/058279, filed Apr. 27, 2009, which claims priority under 35 U.S.C. §119 to Japanese Patent Application No. JP 2008-119847, filed May 1, 2008. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an electrical connector assembly, and in particular an electrical connector assembly having a first connector and a second connector which can easily disengage from one another by exerting an excessive rotational moment on the first connector. 
     BACKGROUND 
     A known electrical connector assembly  100  is shown in  FIG. 7  and disclosed in JP 2004-39600 A. The electrical connector assembly  100  includes a plug  110  and a plug receptacle  130  that connect with each other. The plug  110  connects to a power cord  120 , and the plug receptacle  130  mounts to a vessel body  140  of an electric pot or the like. 
     In this case, the plug  110  includes an insulating plug body  111 , and a pair of plate springs  114  that are installed inside of the plug body  111 . 
     A pair of plate spring receiving cavities  112  open in the front (bottom in  FIG. 7 ) is provided in the plug body  111 . In addition, a pair of magnet holders  113  is provided on left and right outer sides of the plate spring receiving cavities  112  in the plug body  111 . A magnet  116  and a magnet  117  are integrally joined to the outer surface of the magnetic  116  and positioned in each of the magnet holders  113 . 
     Moreover, the plate springs  114  are each formed of a metal that is resiliently deformable in the front-and-back direction. A core wire  121  of the power cord  120  is connected to each back end of the respective plate springs  114 , and a contact portion  115  is provided on each front end of the respective plate springs  114 . 
     Furthermore, the plug receptacle  130  with which the plug is mated includes an insulating plug receptacle body  131  attached to the vessel body  140  and a pair of electrode pins  133  mounted on the plug receptacle body  131 . 
     The plug receptacle body  131  includes a plug-receiving recess  132  open in the front. A pair of magnetic material  134  (not magnetized) is provided on left and right outer sides of the plug-receiving recess  132  in the plug receptacle body  131  so as to face the plug-receiving recess  132 . The magnetic materials  117  provided on the plug  110  are to abut the magnetic material  134 , respectively. 
     The respective electrode pins  133  are pin members made of metal, and are provided at positions where the contact portions  115  of the respective plate springs  114  provided on the plug  110  make contact. 
     When the plug  110  is inserted in the plug receptacle  130  in the direction of arrow A in  FIG. 7 , the respective electrode pins  133  are inserted into the respective plate spring receiving cavities  112  of the plug  110 . Then, tip ends of the respective electrode pins  133  make contact with the contact portions  115  of the respective plate springs  114 , and the respective electrode pins  133  depress the respective plate springs  144  (each of the plate springs is elastically deformed rearward), generating a predetermined contact pressure. Moreover, at this time, the magnetic materials  117  of the plug  110  are attracted to the magnetic material  134  of the plug receptacles  130 , respectively, when the front face of the plug  110  abuts the bottom of the plug-receiving recess  132  of the plug receptacle  130 . 
     Accordingly, excessive rotational moment may be exerted on the plug  110  in the left-and-right direction (direction of arrow B in  FIG. 7 ) or up-and-down direction (direction orthogonal to the space in  FIG. 7 ), and an external force at least equal to attractive force between the magnetic materials  117  and the magnetic material  134  may be exerted on the plug  110 . For example, this is a case when an article is caught by the power cord  120  connected to the plug  110 . In this case, the plug  110  becomes disengaged from the plug receptacle  130 , cutting off power distribution. In this manner, mechanical connection of the plug  110  and the plug receptacle  130  in the electrical connector assembly  100  is made using magnetic materials. As a result, the plug  110  may be easily disengaged from the mating plug receptacle  130  by exerting excessive rotational moment on the plug  110 . 
     In addition, an known electrical connector assembly having a known connector  200  can be easily disengaged from the mated counterpart connector is disclosed in JP 2002-252066 A, and shown in  FIG. 8  and  FIG. 9 . 
     The electrical connector  200  is a known right-angled coaxial electrical connector, as shown in  FIG. 8 , and connects a coaxial cable (not illustrated in the drawings) to a mating coaxial connector (not illustrated in the drawings). The electrical connector  200  includes a shell subassembly  210 , a collar subassembly  220 , a pin contact  230 , and a dielectric  240 . 
     The shell subassembly  210  includes a metal back shell  211  connected to the outer conductor of the coaxial cable. A through-hole  212  extending in the front-and-back direction to receive the dielectric  240  is formed in the back shell  211 . A metal front shell  213  is attached to the front end of the back shell  211 . The front shell  213  is a cylindrical member having multiple flexible cantilever spring fingers  216  extending frontward from a cylindrical base  214 , as shown in  FIG. 9 . Between adjacent spring fingers  216  are slits  215  that open on the front side, allowing the respective spring fingers  216  to easily deflect inward and outward. Ribs  217  protruding inward are positioned near the front ends of the respective spring fingers  216 . Each of the ribs  217  are made to engage with an opposite surface of the outer conductor of the mating coaxial connector. 
     The collar subassembly  220  includes a housing  221  arranged at a position where a part of the front shell  213  and the back shell  211  surrounds. The housing  221  is movable between a neutral position shown in  FIG. 8  and back-and-forth positions before and after the neutral position. The housing  221  is made to control displacement of outer sides of the respective spring fingers  216  when in the neutral position. Coil springs  222 , which urge the back shell  211  and the housing  221  in respective opposite directions from each other to the front-and-back direction, are provided on the periphery of the back shell  211 . 
     The dielectric  240  is placed within the through-hole  212  of the back shell  211 . The pin contact  230  is a metal pin member functioning as a central conductor, and is arranged at the center portion of the dielectric  240 . The front end side of the pin contact  230  protrudes inward of the front shell  213 . 
     In order to connect the mating coaxial connector with the electrical connector  200  that is configured as such, a hand is used to make the housing  221  of the collar subassembly  220  resist compressive force of the coil springs  222  so as to move rearward. Then, displacement of the outer sides of the respective spring fingers  216  provided in the front shell  213  is possible. When the mating coaxial connector connects within the front shell  213 , the respective spring fingers  216  in the front shell  213  are displaced outward, and the pin contact  230  makes contact with a central contact (not illustrated in the drawings) of the mating coaxial connector. When the hand releases the housing  221  of the collar subassembly  220 , the housing  221  is positioned at the natural position, and outward movement of the respective spring fingers  216  is controlled, completing mating thereof. 
     In order to release the mating of the mating coaxial connector with the electrical connector  200 , a hand is used to make the housing  221  of the collar subassembly  220  resist compressive force of the coil springs  222  so as to move rearward. Then, displacement of the outer sides of the respective spring fingers  216  provided in the front shell  213  is possible. In this state, when the mating coaxial connector is pulled out of the front shell  213 , the respective spring fingers  216  in the front shell  213  are displaced outward, canceling the contact condition of the central contact of the mating coaxial connector with the pin contact. This releases the mating of the mating coaxial connector with the electrical connector  200 . 
     With such electrical connector  200 , easy outward displacement of the respective spring fingers  216  in the front shell  213  is possible when pulling out the mating coaxial connector from the front shell  213 . As a result, the mating coaxial connector may be easily removed from the electrical connector  200 . 
     However, the electrical connector assembly  100  shown in  FIG. 7  and the electrical connector  200  shown in  FIG. 8  have several problems. 
     Namely, in the case of the electrical connector assembly  100  shown in  FIG. 7 , the plate springs  114  are elastically deformable in the front-and-back direction in order to bias the contact portions  115 . Therefore, relatively large spaces in the front-and-back direction for holding the plate springs  114  are required. 
     Moreover, since mechanical connection of the plug  110  and the plug receptacle  130  is made using magnetic materials, there are such problems that external magnetic metal is attracted to the magnetic materials, which increases the costs of manufacturing and repair. Particularly, when the electrical connector assembly  100 , connected to a DC power cable of a laptop computer or the like, is used, there is chance that the magnetic materials may adversely affect card magnetic data. 
     Furthermore, in the case of the electrical connector  200  shown in  FIG. 8 , there is an inconvenience when excessive rotational moment has been exerted on the mating coaxial connector in the left-and-right direction or the up-and-down direction in a connected state of the electrical connector  200  and mating coaxial connector. Namely, since mating length of the electrical connector  200  and mating coaxial connector is long, when the aforementioned rotational moment is exerted on the mating coaxial connector, constructional elements of the electrical connector  200  including the pin contact  230  and constructional elements of the mating coaxial connector may be damaged. 
     SUMMARY 
     Accordingly, the invention has been made to solve the above problems, among others, and it is an objective of the invention to provide an electrical connector assembly, which can easily disengage a connector from a mating connector without damaging the constructional elements, notably when excessive rotational moment is exerted on the connector in a connected state. 
     The electrical connector assembly includes a first connector and a second connector that connect with each other. The first connector includes a first housing, a first contact, and a latch. The second connector includes a second housing having a second contact and a shell attached to the second housing so as to cover the second housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail in the following with reference to the embodiments shown in the drawings. Similar or corresponding details in the Figures are provided with the same reference numerals. The invention will be described in detail with reference to the following figures of which: 
         FIG. 1  is a plan view of an electrical connector assembly according to the invention, and shows as a partial cross-sectional view of a rear surface side; 
         FIG. 2  is an enlarged view of a portion of the electrical connector assembly indicated by arrow  2  in  FIG. 1 , showing a first and second connector of the electrical connector assembly according to the invention; 
         FIG. 3  is an enlarged view of the portion indicated by arrow  2  in  FIG. 1 , showing a first connector of the electrical connector assembly rotated away from a second connector of the electrical connector assembly; 
         FIG. 4A  is a partial cross-sectional view of the electrical connector assembly of  FIG. 1  cut at a mating portion between the first and second connector; 
         FIG. 4B  is another partial cross-sectional view of the electrical connector assembly of  FIG. 1  cut at the mating portion between the first and second connector; 
         FIG. 5A  is a plan view of the first connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 5B  is a front view of the first connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 5C  is a side view of the first connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 6A  is a plan view of the second connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 6B  is a front view of the second connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 6C  is a side view of the second connector of the electrical connector assembly of  FIG. 1 ; 
         FIG. 7  is a cross-sectional view of a known electrical connector assembly; 
         FIG. 8  is a cross-sectional view of a known electrical connector of another known electrical connector assembly; and 
         FIG. 9  is a cross-sectional view of an outer conductor used in the known electrical connector of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Hereafter, an embodiment of the invention will be described with reference to the drawings. 
     An electrical connector assembly  1  according to the invention is shown in  FIG. 1 . The electrical connector assembly includes a first connector  10  and a second connector  20  that connect with each other. A power cable  30 , for example, a direct-current power cable of a laptop personal computer is connected to the first connector  10 . Meanwhile, the second connector  20  is mounted on a circuit board (not illustrated in the drawing), for example, a circuit board within the laptop personal computer. 
     The first connector  10  has a first housing  11 , two first contacts  16 , and a latch  14 , as shown in  FIG. 1  and  FIG. 5 . 
     The first housing  11  includes a housing main body  11   a  having an approximate rectangular solid shape, and a first mating part  12 , which protrudes forward from the front end of the housing main body  11   a , as shown in  FIG. 1 ,  FIG. 4 , and  FIG. 5 . The first housing  11  is formed by molding an insulating synthetic resin. The first mating part  12  has an approximate rectangular shape with smaller dimensions than the housing main body  11   a . An approximately rectangular mating recess  13  having an aperture open to a front face is formed in the first mating part  12 . The front end side of the first mating part  12  is a mating side for connection with the second connector  20 . 
     The two first contacts  16  are contained within left and right ends of the mating recess  13  as shown in  FIG. 5B . The first contacts  16  on the left and right sides are formed in mirror symmetry. Each of the first contacts  16  has a base  16   a , an upper elastic contact portion  16   b , a lower elastic contact portion  16   c , and a side elastic contact portion  16   d , as shown in  FIG. 1  to  FIG. 4  and  FIG. 5B . The respective first contacts  16  are formed by stamping and forming sheet metal. The base  16   a  is attached to the housing main body  11   a  of the first housing  11 , and the back end side thereof is connected to the core wire (not illustrated in the drawings) of the power cable  30 . The upper elastic contact portion  16   b  extends in a cantilever form from the base  16   a  toward the upper side of a second mating part  22  and the mating side, as shown in  FIG. 4B . This upper elastic contact portion  16   b  makes elastic contact from above with an upper contact portion  26   a  of a second contact  26  described later provided on the second connector  20 . The lower elastic contact portion  16   c  extends in a cantilever form from the base  16   a  toward the lower side of the second mating part  22  and the mating side. This lower elastic contact portion  16   c  makes elastic contact from below with a lower contact portion  26   b  of the second contact  26  on the second connector  20 . Furthermore, the side elastic contact portion  16   d  extends in a cantilever form from the base  16   a  toward the side of the second mating part  22  and the mating side. The side elastic contact portion  16   d  of the left side first contact  16  extends toward the right side of the second mating part  22 . Moreover, the side elastic contact portion  16   d  of the right side first contact  16  extends toward the left side of the second mating part  22 . These side elastic contact portions  16   d  make elastic contact from the sides with side contact portions  26   c  of the second contact  26 , respectively. 
     The latch  14  is attached to the first housing  11  so as to cover the first mating part  12 , as shown in  FIG. 1 ,  FIG. 4 , and  FIG. 5 . The latch  14  is formed by stamping and forming sheet metal. The latch  14  includes an upper latching part  14   a , which extends to the mating side along the top of the first mating part  12 , and a lower latching part  14   b , which extends to the mating side along the bottom of the first mating part  12  and is paired with the upper latching part  14   a . The latch  14  also includes a left latching part  14   c , which extends to the mating side along the left side of the first mating part  12 , and a right latching part  14   d , which extends to the mating side along the left side of the first mating part  12  and is paired with the left latching part  14   c . As a result, the latch  14  includes two pairs of latching parts: the upper latching part  14   a  and the lower latching part  14   b , and the left latching part  14   c  and the right latching part  14   d . A projection convexly curving outward is formed on the respective latching parts  14   a ,  14   b ,  14   c , and  14   d , and these projections latch onto and engage with recesses concavely curving inside of elastic latching parts  24   a ,  24   b ,  24   c , and  24   d , respectively, described later. 
     Meanwhile, the second connector  20  has a second housing  21 , two second contacts  26 , and a shell  23 , as shown in  FIG. 1  and  FIG. 6 . 
     The second housing  21  is formed in an approximately rectangular solid form and includes the second mating part  22  protruding forward from the front end surface thereof. The second housing  21  and the second mating part  22  are formed integrally by molding an insulating synthetic resin. The second mating part  22  is formed in an approximate rectangular solid form with smaller dimensions than the second housing  21  and allowing reception within the mating recess  13  of the first housing  11 . The front end side of the second mating part  22  is the mating side with the first connector  10 . 
     The two second contacts  26  are placed on left and right ends of the second mating part  22  as shown in  FIG. 6B . The second contacts  26  on the left and right sides are formed in mirror symmetry. Each of the second contacts  26  have the upper contact portion  26   a , the lower elastic contact portion  26   b , the side contact portion  26   c , and a leg  26   d , as shown in  FIG. 1  to  FIG. 4  and  FIG. 6B . The respective second contacts  26  are formed by stamping and forming sheet metal. One end of the leg  26   d  is attached to the second housing  21 , and the other end thereof is bent in an approximate right angle connected to the circuit board (not illustrated in the drawings) on which the second connector  20  is mounted. The upper contact portion  26   a  extends to the mating side along a top surface  22   a  of the second mating part  22  from one end side of the leg  26   d . This upper contact portion  26   a  makes contact with the bottom surface of the upper elastic contact portion  16   b  of the first contact  16 . Moreover, the lower contact portion  26   b  extends to the mating side along bottom surface  22   b  of the second mating part  22  from the other end side of the leg  26   d . This lower contact portion  26   b  makes contact with the top surface of the lower elastic contact portion  16   c  of the first contact  16 . Furthermore, the side contact portion  26   c  extends to the mating side along a side surface  22   c  of the second mating part  22  from the one end side of the leg  26   d . The side contact portion  26   c  on the right side second contact  26  extends along the left side surface of the second mating part  22 , and the side contact portion  26   c  on the left side second contact  26  extends along the right side surface of the second mating part  22 . These side contact portions  26   c  make contact with the side surfaces of the side elastic contact portion  16   d  of the first contact  16 , respectively. 
     The shell  23  is attached to the second housing  21  so as to cover it, as shown in  FIG. 1  to  FIG. 4  and  FIG. 6 . The shell  23  is formed by stamping and forming a metal member. The shell  23  includes two upper elastic latching parts  24   a , which are positioned on the upper outer side of the second mating part  22  and extend in a cantilever form to the mating side from an upper wall surface  23   a  of the shell  23 . The shell  23  also includes two lower elastic latching parts  24   b , which are positioned on the lower outer side of the second mating part  22  and extend in a cantilever form to the mating side from a lower wall surface  23   b  of the shell  23 , and are paired with the two upper elastic latching parts  24   a . The shell  23  further includes a left elastic latching part  24   c , which is positioned on the left outer side of the second mating part  22  and extends in a cantilever form to the mating side from a left wall surface  23   c  of the shell  23 . Moreover, the shell  23  includes a right elastic latching part  24   d , which is positioned on the right outer side of the second mating part  22  and extends towards the mating side from a right wall surface  23   d  of the shell  23 , and is paired with the left elastic latching part  24   c . As a result, the shell  23  includes three pairs of latching parts: the upper latching parts  24   a  and the lower latching parts  24   b  making two pairs, and the left latching part  24   c  and the right latching part  24   d  making a pair. A recess that curves inward is formed on the respective elastic latching parts  24   a ,  24   b ,  24   c , and  24   d , and the projections of the latching parts  14   a ,  14   b ,  14   c , and  14   d  elastically latch onto and engage with these recesses, respectively. Furthermore, fixing parts  23   e  fixing the shell  23  to the circuit board are provided on the left and right wall surfaces  23   c  and  23   d  of the shell  23 . 
     Note that reference numeral  27  in  FIG. 6B  denotes a mating detection contact provided at the center in the left-and-right direction of the second mating part  22 . This mating detection contact  27  makes contact with a mating detection terminal  17  (see  FIG. 5B ) provided on the first connector  10  when the first connector  10  and the second connector  20  are mated. The mating detection contact  27  is bent in an approximate right angle once it extends outward from the second connector  20  and connected to the circuit board, as shown in  FIG. 6C . 
     Next, a method of mating the first connector  10  and the second connector  20  is described. 
     The second mating part  22  of the second connector  20  connects with the mating recess  13  of the first mating part  12  in the first connector  10 . Accordingly, the upper latching part  14   a  of the first connector  10  latches onto the upper elastic latching part  24   a  of the second connector  20 , the lower latching part  14   b  latches onto the lower elastic latching part  24   b , the left latching part  14   c  latches onto the right elastic latching part  24   d , and the right latching part  14   d  latches onto the left elastic latching part  24   c . This completes mating of the first connector  10  and the second connector  20 . 
     At the time of connection between the first connector  10  and the second connector  20 , the first contact  16  of the first connector  10  makes elastic contact with the second contact  26  of the second connector  20 . At this time, the upper elastic contact portion  16   b  of the first contact  16  makes elastic contact from above with the upper contact portion  26   a  of the second contact  26 . Moreover, the lower elastic contact portion  16   c  makes elastic contact from below with the lower contact portion  26   b  of the second contact  26 . Furthermore, the side elastic contact portions  16   d  make elastic contact from the sides with the side contact portions  26   c  of the second contact  26 , respectively. In this manner, the first contact  16  and the second contact  26  make contact at three points, allowing improvement in contact certainty. Since the first contact  16  is connected to the power cable  30 , relatively large current flows to the first contact  16  and the second contact  26 , and contact is made at three points, this surely allows a large current to flow. 
     In order to release the mating of the first connector  10  and the second connector  20 , the first contact  10  connected to the power cable  30  should be pulled out of the second connector  20 . This releases the latching engagement of the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d  and the latching parts  14   a ,  14   b ,  14   c , and  14   d , respectively, and the mating of the first connector  10  and the second connector  20 . 
     Here, excessive rotational moment may be exerted on the first connector  10  in the left-and-right direction and up-and-down direction when viewed from the rear surface side. For example, when an article may catch the power cord  30  connected to the first connector  10 . 
       FIG. 1  to  FIG. 3  show operations of the left latching part  14   c  and the right elastic latching part  24   d , and the right latching part  14   d  and the left elastic latching part  24   c  when excessive rotational moment has been exerted leftward (direction of arrow C) on the first connector  10  when viewed from the rear surface side in the mating state of the connectors  10  and  20 . 
     As shown in  FIG. 1 , when excessive rotational moment is exerted leftward on the first connector  10 , when viewed from the rear surface side, the first connector  10  rotates leftward with the left elastic latching part  24   c  of the second connector  20  and the right latching part  14   d  of the first connector  10  as a pivot point. Then, as shown in  FIG. 1  to  FIG. 3 , latching engagements other than those based on said pivot point, namely latching engagement of the right elastic latching part  24   d  and the left latching part  14   c , and although not illustrated in the drawings, latching engagement of the upper elastic latching part  24   a  and the upper latching part  14   a , and latching engagement of the lower elastic latching part  24   b  and the lower latching part  14   b  are all released. 
     Moreover, although not illustrated in the drawings, when excessive rotational moment is exerted rightward on the first connector  10  when viewed from the rear surface side, the first connector  10  rotates rightward with the right elastic latching part  24   d  of the second connector  20  and the left latching part  14   c  of the first connector  10  as a pivot point. Then, latching engagements other than those based on said pivot point, namely latching engagement of the left elastic latching part  24   c  and the right latching part  14   d , latching engagement of the upper elastic latching part  24   a  and the upper latching part  14   a , and latching engagement of the lower elastic latching part  24   b  and the lower latching part  14   b  are all released. 
     Similarly, when excessive rotational moment is exerted upward on the first connector  10  when viewed from the rear surface side, the first connector  10  rotates upward with the upper elastic latching part  24   a  of the second connector  20  and the upper latching part  14   a  of the first connector  10  as a pivot point. Then, latching engagements other than those based on said pivot point, namely latching engagement of the lower elastic latching part  24   b  and the lower latching part  14   b , latching engagement of the left elastic latching part  24   c  and the right latching part  14   d , and latching engagement of the right elastic latching part  24   d  and the left latching part  14   c  are all released. 
     Similarly, when excessive rotational moment is exerted downward on the first connector  10  when viewed from the rear surface side, the first connector  10  rotates downward with the lower elastic latching part  24   b  of the second connector  20  and the lower latching part  14   b  of the first connector  10  as a pivot point. Then, latching engagements other than those based on said pivot point, namely latching engagement of the upper elastic latching part  24   a  and the upper latching part  14   a , latching engagement of the left elastic latching part  24   c  and the right latching part  14   d , and latching engagement of the right elastic latching part  24   d  and the left latching part  14   c  are all released. 
     In this manner, the first connector  10  according to the invention rotates in the up-and-down direction or left-and-right direction with a single elastic latching part of the second connector  20  and a single latching part of the first connector  10  as a pivot point and thereby releasing latching engagements other than those based on said pivot point, when excessive rotational moment is exerted on the first connector  10  in the up-and-down direction or left-and-right direction. Therefore, when excessive rotational moment has been exerted on the first connector  10  in a mating state, the latching engagement of the first connector  10  and the second connector  20  is easily released. Accordingly, the first connector  10  may be easily disengaged from the mating connector without damage to constructional elements. 
     With the electrical connector assembly  1  according to the invention, the plate springs  114  deformable in the front-and-back direction are not required to bias the contact portions  115 , as with the conventional electrical connector assembly  100  shown in  FIG. 7 . Therefore, a small-sized electrical connector assembly may be provided without needing relatively large spaces in the front-and-back direction for holding the plate springs  114 . 
     Moreover, with the electrical connector assembly  1  according to the invention, mechanical connection of the first connector  10  and the second connector  20  is prepared by latching engagements of the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d  and the latching parts  14   a ,  14   b ,  14   c , and  14   d , respectively. Therefore, unlike the electrical connector assembly  100  shown in  FIG. 7 , mechanical connection of the plug  110  and the plug receptacle  130  does not need to be made using magnetic materials. Accordingly, there is no issues of damage or increased cost from the magnetic materials. 
     The second mating part  22  of the second connector  20  is at a slant such that the top surface  22   a , the bottom surface  22   b , the left side surface  22   c , and the right side surface  22   d  (only left side surface  22   c  is illustrated in  FIG. 4A  taper off so as to allow rotation of the first connector  10  in the up-and-down direction or left-and-right direction. Therefore, the second mating part  22  of the second connector  20  can certainly secure a gap before the joining recess  13 , allowing the first connector  10  to rotate in the up-and-down direction or left-and-right direction. As a result, the electrical connector assembly  1  may be provided without the second mating part  22  of the second connector  20  hindering rotation of the first connector  10 . 
     Furthermore, with the electrical connector assembly  1  according to the invention, the latching parts  14   a ,  14   b ,  14   c , and  14   d  and the shell  23  having the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d  are made of metal. As a result, wear resistance of the latching parts  14   a ,  14   b ,  14   c , and  14   d  of the first connector  10  and the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d  of the second connector  20  may be improved greater than in the case of non-metal members, such as resin, for example. Furthermore, by grounding the shell  23 , the second connector  20  and the first connector  10  may be grounded via the latching parts  14   a ,  14   b ,  14   c , and  14   d  and the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d.    
     While embodiments of the invention have been illustrated, the present invention is not limited thereto, and various modifications and improvements are possible. 
     For example, two pairs of the latching parts  14   a ,  14   b ,  14   c , and  14   d  of the first connector  10  are provided in the shown embodiment; however, not limited to two pairs, there should at least be two pairs of latching parts extending to the mating side along the upper and lower surfaces and left and right side surfaces of the first mating part  12 . 
     Moreover, three pairs of the elastic latching parts  24   a ,  24   b ,  24   c , and  24   d  of the second connector  20  are provided in the embodiment shown; however, not limited to three pairs, there should at least be two pairs of elastic latching parts extending to the joining side along the upper and lower wall surfaces and left and right wall surfaces of the shell  23  and positioned on the upper and lower outer sides and left and right outer sides of the second mating part  22 . 
     Furthermore, a recess curving inward is formed on the respective elastic latching parts  24   a ,  24   b ,  24   c , and  24   d , and the projections of the latching parts  14   a ,  14   b ,  14   c , and  14   d  elastically latch onto and engage with these recesses, respectively. However, shape of the respective elastic latching parts  24   a ,  24   b ,  24   c , and  24   d , and the latching parts  14   a ,  14   b ,  14   c , and  14   d  is not limited thereto. When excessive rotational moment is exerted on the first connector  10  in the up-and-down direction or left-and-right direction, the first connector  10  should be configured so as to rotate in the up-and-down direction or left-and-right direction with a single elastic latching part of the second connector  20  and a single latching part of the first connector  10  as a pivot point, and release other latching engagements than those based on the pivot point.