Patent Publication Number: US-6902411-B2

Title: Connector assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates to a connector assembly composed of a pair of surface mount connectors. 
     BACKGROUND OF THE INVENTION 
     In recent years, the use of surface-mounted (SMT) connectors for interconnecting circuit boards has grown, because of the ease of electrical connection to elements on the circuit board, the high packaging density of contacts and other advantages. An SMT connector is electrically connected to a circuit board by soldering a soldering part (tine part) of a contact of the connector to a pad on the surface of the circuit board. Some SMT connectors have a soldering peg attached to a housing with an array of contacts. Such SMT connectors with a soldering peg are fixed to a circuit board by soldering the soldering peg to a pad on the surface of the circuit board. However, when the connector is mounted on the circuit board, if the tine parts of the contacts protrude beyond the soldering part of the soldering peg, the connector is inadequately fixed to the circuit board. On the other hand, if the soldering part of the soldering peg protrudes beyond the tine parts of the contacts, the connector cannot be electrically connected to the circuit board, although it can be fixed to the circuit board. 
     To overcome the problem of alignment of the tine parts of the contacts and the soldering part of the soldering peg when the connector is mounted on the surface of the circuit board, an SMT connector having a soldering peg capable of moving with respect to the surface of the circuit board is suggested in Japanese Utility Model Laid-Open No. 5-23429, for example. A connector assembly having a pair of SMT connectors is described, in which each connector has soldering pegs disposed in a movable manner at the longitudinal ends of the housing thereof. 
     When paired connectors are connected to each other, it is desirable that the operator can perceive that the connectors are correctly connected to each other. The SMT connector pair described above does not have any mechanism that allows the operator to perceive the correct connection of the connectors. However, there has been proposed another connector pair having a mechanism that allows the operator to perceive that the connectors are correctly connected to each other in Japanese Patent Laid-Open No. 4-43579, for example. Here, a pair of connectors each having plural contacts is described, in which the contacts of one connector have an inward protrusion that protrudes inwardly, and the contacts of the other connector have an outward protrusion that protrudes outwardly and is formed at a resilient part of the contact which can be deflected inwardly. In this connector pair, when connecting the connectors to each other, if one of the connectors is inserted to the other, than the inward protrusions and the outward protrusions come into contact with each other before the connection process is completed. If the insertion is continued, the inward protrusions and the outward protrusions which are in contact with each other interact, and the resilient parts of the contacts on which the outward protrusions are formed are deflected inwardly. Then, the insertion is further continued, and when the connection process is completed, the resilient parts of the contacts with the outward protrusions, which have been deflected inwardly, return to their original positions, and a tactile response is produced. By feeling the tactile response, the operator can know that the connectors are correctly connected to each other. 
     In recent years, however, downsizing of connectors has been severely required, and to meet the requirement, the connectors have been made thinner. If the mechanism that produces a tactile response described in Japanese Patent Laid-Open No. 4-43579 is used for a low-profile connector assembly, the beam of each contact cannot have a sufficient length. Thus, the contact has a smaller deflection when the connectors are connected to each other, so that an adequate tactile response cannot be produced. In addition, in order to maintain the electrical connection between the contacts with the connectors being connected to each other, the resilient part of the contact having the outward protrusion is designed to return to a state just short of the original state even after the paired connectors are completely connected, so that the resilient part still has some resilient force. The strength of the tactile response produced when the paired connectors described are completely connected depends on to the extent that the resilient part of the contact returns. Thus, if the resilient part has to have some resilient force even after the paired connectors are completely connected, the resilient part cannot return to an adequate extent, so that an adequate tactile response cannot be provided. 
     SUMMARY OF THE INVENTION 
     An exemplary connector assembly according to the present invention includes a pair of connectors, each of the connectors having: an insulating housing; contacts arranged in at least one row in the longitudinal direction of the insulating housing; and soldering pegs that are disposed at the longitudinal ends of the insulating housing and capable of moving vertically. The soldering pegs of one of the connectors each have a pair of engaging arms, each of which is spaced apart from a wall of the insulating housing of the connector and capable of being resiliently deformed outwardly. The soldering pegs of the other of the connectors each have a pair of engaging arms, each of which is spaced apart from a wall of the insulating housing of the connector and capable of being resiliently deformed inwardly. The engaging arms of the soldering pegs each have a locking protrusion. The locking protrusions of the engaging arms interacting during connection of the connectors, whereby the engaging arms are loaded due to the interaction between the locking protrusions during connection of the connectors and substantially unloaded when the connectors are completely connected to each other because the interaction between the locking protrusions is eliminated. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a plug connector of a connector assembly according to an exemplary embodiment of the present invention; 
         FIG. 2  is a front view of the plug connector shown in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of the plug connector shown in  FIGS. 1 and 2  taken along the line A–A′ in  FIG. 2 ; 
         FIG. 4  is a plan view of a receptacle connector of a connector assembly according to an exemplary embodiment of the present invention; 
         FIG. 5  is a front view of the receptacle connector shown in  FIG. 4 ; 
         FIG. 6  is a cross-sectional view of the receptacle connector shown in  FIGS. 4 and 5  taken along the line B–B′ in  FIG. 5 ; and 
         FIG. 7  shows the plug connector shown in  FIG. 1  and the receptacle connector shown in  FIG. 4  being connected to each other. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Following is a description of an exemplary embodiment of the connector assembly of the present invention with reference to the attached drawings. 
     A connector assembly according to this embodiment is composed of a plug connector and a receptacle connector which mate with each other. 
     First, the plug connector will be described. 
       FIG. 1  is a plan view of the plug connector of the connector assembly according to the embodiment of the present invention.  FIG. 2  is a front view of the plug connector shown in  FIG. 1 , and  FIG. 3  is a cross-sectional view of the same connector taken along the line A–A′. 
     A plug connector  10 , shown in  FIGS. 1–3 , is a surface-mounted (SMT) connector, which is configured to be mounted on a surface of a circuit board (not shown). In  FIGS. 1 to 3  the plug connector  10  is not yet mounted on the circuit board. The plug connector  10  has an insulating housing  11  extending horizontally in this drawing, plural contacts  12  arranged in two rows along the length (the longitudinal direction) of the insulating housing  11 , and soldering pegs  13  moveably disposed in respective guiding sections  14  at the longitudinal ends of the insulating housing  11 . 
     The insulating housing  11 , shown in  FIG. 1 , is made of resin. 
     In  FIG. 1 , the contacts  12  are shown as arranged in two, upper and lower, rows, and the contacts  12  in the upper row and the contacts  12  in the lower row are arranged to oppose each other. In the illustrated embodiment, each of the contacts  12  is made of a copper alloy and substantially L-shaped (see  FIG. 3 ). One end of each contact  12  constitutes a tine section  121  to be soldered to a pad on the circuit board (not shown). The other end thereof is bent to have an angled U shape, as shown in  FIG. 3 . In addition, at the latter end, the contact  12  has a projection  122  configured to make contact with a corresponding contact of a mating connector (described hereafter). The projection  122  may be formed by coining, for example, and protrudes toward the opposing contact  12 . The tine sections  121  of the contacts  12  have the same height (that is, are aligned at the bottom, as shown by the alternate short and long dash line in  FIG. 2 ) and may be formed in the insulating housing  11  by insert molding, for example. 
     The soldering pegs  13  shown in  FIGS. 1 and 2  are formed to have a high dimensional precision, by only die cutting of one copper alloy plate, for example, without any forming, such as bending. Each soldering peg  13  has a soldering part  131 , which is to be soldered to a pad on the circuit board. Since the soldering parts  131  are soldered to the pads on the circuit board, the plug connector  10  is rigidly fixed to the circuit board. That is, the soldering pegs  13  serve to fix the plug connector  10  to the circuit board. The soldering pegs  13  shown in  FIGS. 1 and 2  serving in this way are attached to the insulating housing  11  in a movable manner. They can vertically move within a predetermined range. In  FIG. 2 , the soldering parts  131  of the soldering pegs  13  are shown protruding slightly below the tine sections  121  due to their own weights. However, when mounting the plug connector  10  on the circuit board, the soldering pegs  13  move upward until the level of the soldering parts  131  corresponds with that of the tine sections  121 , and the soldering parts  131  comes into contact with the pads on the circuit board. That is, when the plug connector  10  is mounted on the circuit board, the tine sections  121  and the soldering parts  131  are coplanar. Therefore, the plug connector  10  shown in  FIG. 1  can be reliably electrically connected to the circuit board by the tine sections  121  and can be reliably fixed thereto by the soldering parts  131 . Further description of the soldering pegs  13  will be made later. 
     Now, the receptacle connector, the other connector in the connector assembly according to this embodiment of the present invention, will be described. 
       FIG. 4  is a plan view of the receptacle connector  20  in the connector assembly according to the present exemplary embodiment of the invention.  FIG. 5  is a front view of the receptacle connector  20  shown in  FIG. 4 .  FIG. 6  is a cross-sectional view of the receptacle connector  20  taken along the line B–B′ in  FIG. 5 . 
     As with the counterpart plug connector  10  shown in  FIG. 1 , a receptacle connector  20  shown in  FIG. 4  is a surface-mounted connector, which is configured to be mounted on a surface of a circuit board (not shown). Again, the receptacle connector  20  shown has not yet been mounted on the circuit board. As with the plug connector  10  shown in  FIG. 1 , the receptacle connector  20  has an insulating housing  21  extending horizontally in  FIG. 4 , plural contacts  22  arranged in two rows along the length (the longitudinal direction) of the insulating housing  21 , and soldering pegs  23  disposed in respective guiding sections  24  at the longitudinal ends of the insulating housing  21 . 
     The exemplary insulating housing  21  shown in  FIG. 4  is also made of resin, and in  FIG. 4 , the contacts  22  in the upper row and the contacts  22  in the lower row are arranged opposing each other. Each contact  22 , which is made of a copper alloy in the illustrated embodiment, is substantially S-shaped (see  FIG. 6 ) and therefore is resilient. One end of each contact  22  constitutes a tine section  221  to be soldered to a pad on the circuit board (not shown), and the other end thereof constitutes a contact section  222  formed taking advantage of the arc of the S shape. When the plug connector  10  shown in  FIG. 1  is connected to the receptacle connector  20 , the contact sections  222  come into contact with the contacts  12  of the plug connector  10 , and the electrical connection between the contacts  12  and  22  is established. When the connectors are connected to each other, the projections  122  of the contacts  12  of the plug connector  10  make the contacts  22  of the receptacle connector  20  deflect inwardly (toward the respective opposing contacts  22 ), thereby assuring the electrical connection between the contacts  12  and  22  owing to the resiliency. The tine sections  221  of the contacts  22  of the receptacle connector  20  have the same height (that is, are aligned at the bottom, as shown by the alternate short and long dash line in  FIG. 5 ) and are attached in the insulating housing  21  by press fitting, for example. As with the soldering pegs  13  of the plug connector  10 , the soldering pegs  23  shown in  FIGS. 4 and 5  may be formed only by die cutting of one copper alloy plate, for example, and each have a soldering part  231 , which is to be soldered to a pad on the circuit board and serve the same as the soldering peg  13  of the plug connector  10 . In addition, as with the soldering pegs  13  of the plug connector  10 , the soldering pegs  23  shown in  FIGS. 4 and 5  are attached to the insulating housing  21  in a movable manner. Referring to  FIG. 5 , the soldering parts  231  of the soldering pegs  23  protrude slightly below the tine sections  221  due to their own weights. However, when the receptacle connector  20  shown in  FIG. 5  is mounted on the circuit board, the tine sections  221  and the soldering parts  231  become coplanar. Therefore, the receptacle connector  20  shown in  FIG. 4  can be reliably electrically connected to the circuit board by the tine sections  221  and can be reliably fixed thereto by the soldering parts  231 . 
     Now, how the soldering pegs  13  and  23  work when the plug connector  10  shown in  FIG. 1  and the receptacle connector  20  shown in  FIG. 4  are connected to each other will be described. 
       FIG. 7  shows the plug connector of  FIG. 1  and the receptacle connector of  FIG. 4  being connected to each other. 
       FIG. 7  shows the connector assembly  1  according to an exemplary embodiment, the plug connector  10  shown in  FIG. 1  being shown at the upper part of this drawing, and the receptacle connector shown in  FIG. 4  being shown at the lower part thereof.  FIG. 7  is intended primarily to illustrate the soldering pegs  13 ,  23  of the connectors  10 ,  20 , so that the contacts  12 ,  22  of the connectors  10 ,  20  are shown only in part, including the tine sections  121 ,  221 . Furthermore, in the actual connector assembly, when the plug connector  10  shown in  FIG. 1  and the receptacle connector  20  shown in  FIG. 4  are connected to each other, the connectors  10  and  20  have already been mounted on the surfaces of the respective circuit boards. However, in  FIG. 7 , the connectors  10  and  20  being connected to each other are yet to be mounted on the circuit boards, and the coplanarity of the tine sections  121  and the soldering parts  131  of the connector  10  and of the tine sections  221  and the soldering parts  231  of the connector  20  are neglected. 
     The soldering peg  13  ( 23 ) of the connector  10  ( 20 ) has soldering parts  131  ( 231 ) at the ends, a base part  132  ( 232 ) connecting the soldering parts  131  ( 231 ) to each other, and a pair of opposing engaging arms  133  ( 233 ) protruding from the base part  132  ( 232 ). The paired engaging arms  133  ( 233 ) are resiliently deformable and each have a locking protrusion  1331  ( 2331 ). The locking protrusions  1331  of the soldering peg  13  of the plug connector  10  shown in the upper area of the drawing protrude outwardly (away from their respective opposing engaging arms  133 ), and the locking protrusions  2331  of the soldering peg  23  of the receptacle connector  20  shown in the lower area of the drawing protrude inwardly (toward their respective opposing engaging arms  233 ). In the insulating housing  11  ( 21 ) of the plug (receptacle) connector  10  ( 20 ), soldering peg accommodating chambers  111  ( 211 ) for accommodating the soldering peg  13  ( 23 ) in a movable manner are provided in the guiding section  14  ( 24 ) at each of the longitudinal ends of the insulating housing  11  ( 21 ). The soldering peg  13  ( 23 ) of the plug (receptacle) connector  10  ( 20 ) is disposed in the soldering peg accommodating chamber  111  ( 211 ). The soldering peg  13  ( 23 ) disposed in the soldering peg accommodating chamber  111  ( 211 ) is spaced apart from a wall  11   a  ( 21   a ) of the insulating housing that defines the soldering peg accommodating chamber  111  ( 211 ). As for the pair of engaging arms  133  ( 233 ), each engaging arm  133  ( 233 ) is spaced apart from the wall by a distance X, indicated by the double-headed arrow X, in the X direction, the horizontal direction in  FIG. 7  and spaced apart from the wall by a distance Z, indicated by the double-headed arrow Z, in the Z direction, the vertical direction in  FIG. 7 . These spacings in two directions allow the paired engaging arms  133  ( 233 ) of the soldering peg  13  ( 23 ) of the connector  10  ( 20 ) to pivot. That is, when connecting the connectors  10  and  20  shown in  FIG. 7  to each other, the plug connector  10  shown in the upper area of the drawing is inserted into the receptacle connector  20  shown in the lower area thereof. At this time, first, the locking protrusions  1331  of the soldering peg  13  come into contact with the locking protrusions  2331  of the soldering peg  23 . If the insertion of the plug connector  10  is continued, the locking protrusions  1331  and  2331  which are in contact with each other interact, so that each of the engaging arms  133  of the soldering peg  13  is deflected by pivoting inwardly around the asterisk mark (*) in the drawing, and each of the engaging arms  233  of the soldering peg  23  is deflected by pivoting outwardly around the asterisk mark (*) in the drawing. That is, the engaging arms  133 ,  233  are loaded. Then, the insertion is further continued, and when it is completed, the deflected engaging arms  133 ,  233  return to their original positions and provide a tactile response. Then, the locking protrusions  1331  of the upper soldering peg  13  and the locking protrusions  2331  of the lower soldering peg  23  are engaged with each other. By feeling the tactile response, the operator can know that the connectors  10  and  20  are correctly connected to each other. Once the lock protrusions  1331  and  2331  are engaged with each other, the engaging arms  133  and  233  are in exactly the same state as before connection due to their resiliency, and therefore, are substantially unloaded. In the connector assembly  1  according to this embodiment, the tactile response, which is produced when the connectors  10  and  20  are correctly connected to each other, is provided mainly by the soldering pegs  13 ,  23 , and the contacts  12 ,  22  shown in  FIGS. 3 and 6  provide no or little tactile response. In addition, in the connector assembly  1  according to this embodiment, the strength of the tactile response depends on the displacements of the engaging arms  133 ,  233  during connection of the connectors  10  and  20 . Since the soldering pegs  13 ,  23  are intended primarily to fix the connectors to the circuit boards, once the connectors  10  and  20  are connected to each other, the soldering pegs are less responsible for connection of the connectors than the contacts  12  and  22 . Thus, in the connector assembly  1  according to this embodiment, once the connectors are connected to each other, the engaging arms  133 ,  233  can be substantially unloaded. Thus, the displacements of the engaging arms  133 ,  233  are increased, so that a more positive tactile response can be provided when the connectors  10  and  20  are correctly connected to each other. The “substantially unloaded” state includes a state where the engaging arms  133 ,  233  are in contact with the respective counterpart engaging arms  233 ,  133 . In addition, the thicknesses of the engaging arms  133 ,  233  (that is, the widths the engaging arms along the surface thereof, indicated by reference symbols W 1 , W 2  in  FIG. 7 ) are more than the thicknesses of the contacts  12 ,  22  shown in  FIGS. 3 and 6 , respectively, and thus, the engaging arms  133 ,  233  have an increased rigidity. Thus, a further more positive tactile response can be provided. 
     The soldering pegs  13  and  23  are attached to the insulating housings  11  and  21 , respectively, in a movable manner as described above; and the movability is assured by the spacings in the Z direction. That is, the spacings can serve not only for accommodating the engaging arms  133 ,  233  deflected to provide a tactile response but also for assuring the movability of the soldering pegs  13 ,  23 , and thus, the connectors can be reduced in size. In addition, if press fitting is used, the part of the insulating housing to be subject to press fitting has to be made thicker. However, the soldering pegs  13 ,  23  of the connectors  10 ,  20  are not attached by press fitting, so that there is no need to provide the thicker parts on the insulating housings  11 ,  21 , and accordingly, the connectors can be reduced in size. Since the soldering pegs  13 ,  23  may be formed only by die cutting, without bending, as described above, the footprints (projection areas) of the soldering pegs on the connectors  10 ,  20  can be reduced, and thus, the connectors can be further reduced in size. Furthermore, since the soldering pegs may be formed by die cutting, the thicknesses of the engaging arms can be adjusted, and a desired rigidity can be imparted to the engaging arms. The higher the rigidity, the more positive tactile response can be provided. 
     In addition, the soldering peg  23  of the receptacle connector  20  shown in the lower area of  FIG. 7  has a pair of supporting protrusions  234  located inside of the pair of engaging arms  233 . As described above, since the soldering pegs  13 ,  23  of the connectors  10 ,  20  may be formed by die cutting, the soldering pegs may have rough surfaces. Thus, when the engaging arms  133 ,  233  are deflected during connection of the connectors, high friction is produced between the locking protrusions  1331  and  2331  in contact with each other, so that the engaging arms  233  of the receptacle connector  20  experience not only the force to deflect them outwardly but also a force to pull them inwardly due to the friction. The pair of supporting protrusions  234  on the soldering peg  23  of the receptacle connector  20  is slightly retracted compared with the soldering parts  231  formed outside thereof. When such a force to pull the engaging arms  233  inwardly is exerted thereon, the pair of supporting protrusions  234  comes into contact with the surface of the circuit board, thereby preventing the engaging arms  233  from falling inwardly.