Abstract:
A method for electrically mating a plug connector with a socket connector includes the steps of (a) arranging plug contacts of the plug connector to extend along a first axis, each plug contact having a tip supported thereon by a deflectable portion and extending beyond the plug connector; (b) arranging socket contacts of the socket connector in passageways and extending along a second axis which is substantially normal to the first axis; (c) moving the plug and socket connectors toward each other to insert the tips of the plug contacts into the passageways and forming a point contact engagement with the socket contacts; (d) further moving the plug and socket connectors toward each other to cause deflection of the deflectable portions of the plug contacts with the tips sliding on the socket contacts; and (e) deflecting the deflectable portions of the plug contacts by further moving the plug and socket connectors toward each other to change the point contact between the plug contacts and the socket contacts to a surface contact therebetween.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to an electrical connection system comprising a socket connector and a plug connector mating together, and in particular to an electrical connection method for establishing electrical connection between socket and plug connectors wherein the contact engagement between contact elements thereof change from a point contact to a final surface contact. 
     2. The Prior Art 
     An electrical connection system comprises a plug connector and a socket connector mating with each other is well known in the electronics field. Connectors of this type are disclosed in Taiwan patent application Nos. 84213256 and 85201191. 
     The plug connector and the socket connector both have contacts engageable with each other. Conventionally, the contacts of the plug and socket connectors are engaged with each other in parallel. In other words, the contacts of the plug connector and the contacts of the socket connector are substantially parallel to each other during engagement. To ensure proper engagement between the plug contact and the socket contact, at least one of the contacts forms at least one bent section. Furthermore, the relative position between each socket contact and the corresponding plug contact has to be precise to ensure proper engagement therebetween. Such precise positioning of the contacts in the connectors increases the overall manufacturing cost and the likelihood of unstable electrical engagement. 
     It is thus desirable to have a method for connecting the plug and socket connectors, which does not require high contact positioning precision to obtain a proper and stable engagement therebetween. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide an electrical connection method for connecting socket and plug connectors and establishing a secure electrical engagement therebetween. 
     Another object of the present invention is to provide an electrical connection method for establishing proper electrical engagement between a plug connector and a socket connector which does not require the precise position of contacts. 
     To achieve the above objects, an electrical connection method for mating a plug connector with a socket connector in accordance with the present invention comprises the following steps: (1) arranging plug contacts of the plug connector to extend along a first axis, each plug contact having a tip supported thereon by a deflectable portion and extending beyond the plug connector; (2) arranging socket contacts of the socket connector in passageways and extending along a second axis which is substantially normal to the first axis; (3) moving the plug and socket connectors toward each other to insert the tips of the plug contacts into the passageways and forming a point contact engagement with the socket contacts; (4) further moving the plug and socket connectors toward each other to cause deflection of the deflectable portions of the plug contacts with the tips sliding on the socket contacts; and (5) deflecting the deflectable portions of the plug contacts by further moving the plug and socket connectors toward each other to change the point contact between the plug contacts and the socket contacts to a surface contact therebetween. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the accompanying drawings, in which: 
     FIG. 1 is an exploded view of a plug connector of an electrical connection system in accordance with a first embodiment of the present invention; 
     FIG. 2 is similar to FIG. 1 but taken from a different perspective; 
     FIG. 3 is a cross-sectional view taken along line III—III of FIG. 2; 
     FIG. 4 is an assembled view of FIG. 1; 
     FIG. 5 is a cross-sectional view taken along line V—V of FIG. 4; 
     FIG. 6 is a cross-sectional view taken along line VI—VI of FIG. 4; 
     FIG. 7 is a perspective view of a socket connector of the electrical connection system of the present invention; 
     FIG. 8 is a cross-sectional view taken along line VIII—VIII of FIG. 7; 
     FIG. 9A is a cross-sectional view similar to FIG. 5, but showing a second embodiment of the plug connector of the present invention; 
     FIG. 9B is a cross-sectional view similar to FIG. 5, but showing a third embodiment of the plug connector of the present invention; 
     FIG. 10A is a schematic view showing the spatial relationship between the plug connector and the socket connector when mating the connectors together; 
     FIGS. 10B-10D are cross-sectional, sequential views showing different steps of mating the plug connector with the socket connector; 
     FIG. 11A is a schematic view showing the spatial relationship between the plug connector and a circuit board to be electrically engaged together; and 
     FIGS. 11B-11D are cross-sectional, sequential views showing the different steps when engaging the plug connector with the circuit board. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An electrical connection system in accordance with the present invention comprises a plug connector and a socket connector mating with each other. Both the plug connector and the socket connector comprise conductive contact elements which are engageable with each other when mating the plug and socket connectors together thereby establishing electrical connection therebetween. In the electrical connection system of the present invention, the contact elements of the plug connector are brought into contact with the contact elements of the socket connector in a direction substantially normal thereto and the contact elements of the plug connector are deflected from a substantially normal condition with respect to the contact elements of the plug connector wherein a point contact is formed between each plug contact element and the corresponding socket contact element to a partially parallel condition wherein a surface contact is formed between the plug contact elements and the socket contact elements to ensure a firm contact engagement between. 
     Referring now to the drawings and in particular to FIGS. 1 and 2, a plug connector in accordance with the present invention, generally designated by reference numeral  10 , comprises an elongate insulative housing  4  having a mating face  40   a  and a mounting face  40   b  opposite the mating face  40   a . The mounting face  40   b  defines a cavity  41  therein into which an insert  6  is inserted. 
     Also referring to FIGS. 3 and 4, the housing  4  defines a plurality of contact receiving channels  31  therein disposed in two rows in the lengthwise direction. The contact receiving channels  31  extend from the mating face  40   a  of the housing  4  and into the cavity  41 . A partition wall  312  is formed between two adjacent contact receiving channels  31  of the same row. The two rows of the contact receiving channels  31  are spaced by an internal wall  3  of the housing  4  and bound by two side walls  49  of the housing  4 . Each side wall  49  has an inside face  413 . 
     The cavity  41  forms a shoulder  411  on each side wall  49  of the housing  4 . A number of bores  32  are defined in the internal wall  3  and within the cavity  41  for receiving positioning pins  62  of the insert  6  therein, preferably in an interferential manner for securing the insert  6  in the cavity  41 . The insert  6  further comprises two resilient arms  61  formed at opposite ends thereof, each arm  61  having a barb  611  engageable with an internal shoulder  44  (FIG. 6) formed inside the housing  4  for securing the insert  6  in the housing  4 . The insert  6  also has a plurality of positioning projections  63  for positioning on a circuit board (not shown). 
     Each contact receiving channel  31  receives a plug contact element  5  therein. As shown in FIG. 5, each plug contact element  5  comprises a mating section  53  disposed in the corresponding contact receiving channel  31  and substantially extending along a first axis (not labeled) normal to the mating face  40   a  and a mounting section  51  extending beyond the mounting face  40   b  of the housing  4 . A fixing section  52  is formed between the mating section  53  and the mounting section  51 . The fixing section  52  forms a right-angled portion  530  at a junction with the mating section  53  and is supported on the shoulder  411  of the housing  4  with a portion of the mating section  53  supported by the inside face  413  of the side wall  49  of the housing  4 . The insert  6  has a side flange  64  formed on each side thereof and extending above the shoulder  411  of the side wall  4  thereby overlapping and thus retaining the fixing section  52  in position. 
     In the embodiment illustrated, the fixing section  52  of each plug contact element  5  forms a right-angled portion  510  at a junction with the mounting section  51  which renders the mounting section  51  to be substantially parallel to the mating section  53 . The right-angled portion  510  causes the mounting section  51  to extend in a direction substantially normal to the mounting face  40   b.    
     The mating section  53  of each plug contact element  5  comprises a tip portion  532  extending beyond the mating face  40   a  and inclined with respect to the first axis which is normal to the mating face  40   a  and an arcuate portion  531  connecting the tip portion  532  to the fixing section  52  of the plug contact element  5 . The arcuate portion  531  is convex with respect to the internal wall  3  of the housing  4  and an apex thereof is located proximate or abutting against a corresponding surface  311  of the internal wall  3  for providing resiliency that allows the tip portion  532  to be deflected toward the mating face  40   a . When the tip portion  532  is deflected, the apex of the arcuate portion  531  is moved toward and abuts against the internal wall  3  for supporting the deflection of the tip portion  532 . 
     A shield casing  2  has an open bottom fit over the housing  4  for surrounding the housing  4  (FIGS.  4  and  5 ). Grounding tabs  23  extend from the shield casing  2  for electrically grounding the shield casing  2 . The shield casing  2  has a top wall  21  positioned on the mating face  40   a  of the housing  4 . The top wall  21  of the shield casing  2  defines a central opening  24  for exposing the contact receiving channels  31 . 
     The top wall  21  of the shield casing  2  further defines two pin holes  22 . Corresponding to each pin hole  22  of the shield casing  2 , a bore  42  is defined in the housing  4 . A guide post  1  has a post body  11  and a reduced pin section  12  inserted through the pin hole  22  and fit into the bore  42  with the post body  11  supported on the top wall  21  of the shield casing  2 . The reduced pin section  12  has a tubular end  121  (FIG. 6) which may be expanded to comply with a flaring end of the bore  42  thereby securing the guide post  1 , the shield casing  2  and the housing  4  together. 
     The housing  4  may comprise positioning pins  43  extending from the mounting face  40   b  thereof for properly positioning the plug connector  10  on a device or circuit board (not shown) to which the plug connector  10  is to be mounted. 
     FIG. 7 shows the socket connector in accordance with the present invention, which is designated by reference numeral  70 . The socket connector  70  comprises an elongate insulative housing  71  having a mating face  71   a  (also see FIG. 8) overlappingly engageable with the mating face  40   a  of the housing  4  of the plug connector  10  (FIG. 10D) and a mounting face  71   b  opposite the mating face  71   a.    
     The housing  71  defines a plurality of passageways  711  extending from the mating face  71   a  thereof to a predetermined depth defining a bottom (not labeled). The passageways  711  are disposed in two rows along the lengthwise direction corresponding to the plug contact elements  5  for receiving the tip portions  532  therein. The passageways  711  of the same row are separated by partition walls  714 , while the two rows are separated by an internal wall  715  and bound by two side walls  716  of the housing  71 . The internal wall  715  and the side walls  716  form end faces  711   a  of the passages  711  (FIG.  8 ). 
     A socket contact element  73  is fixed in the housing  71  of the socket connector  70  and associated with each of the passageways  711 . The socket contact element  73  has a mating section  731  supported on the  15  bottom of the passageway  711  and extending along a second axis which is substantially parallel to the mating face  71   a  (and normal to the depth of the passageway  711 ) and a mounting section  732  extending beyond a side wall  71 c of the housing  71  and substantially coplanar with the mounting face  71   b  for surface-mounting to a device or a circuit board (not shown). If desired, the mounting section  732  may extend beyond the mounting face  71   b  rather than the side wall  71   c.    
     The socket housing  71  further comprises positioning pins  713  formed on the mounting face  71   b  for properly positioning the socket connector  70  on a device or a circuit board (not shown). 
     A post receiving hole  712  is defined in the socket housing  71  corresponding to and receiving the post body  11  of the guide post  1  fixed in the plug connector  10  for properly positioning the plug connector  10  with respect to the socket connector  70  as shown in FIG.  10 A. Preferably, a plate member  72  made from a metal sheet is attached to the portion of the socket housing  71  in which each post receiving hole  712  is defined. The plate member  72  defines an opening  721  aligned with the post receiving hole  712  for the reception of the guide post  1 . The plate member  72  may have sideways extensions  722  for soldering to the device or circuit board to which the socket connector  70  is mounted. The plate members  72  are engageable with the top wall  21  of the shield casing  2  of the plug connector  10  and an electrical connection may be formed therebetween for grounding purposes. 
     As shown in FIG. 10A, when mating the plug connector  10  to the socket connector  70 , the plug connector  10  is positioned with respect to the socket connector  70  with the mating faces  40   a ,  71   a  thereof substantially parallel to and facing each other and the guide posts  1  of the plug connector  10  in alignment with the post receiving holes  712  of the socket connector  70 . The plug and socket connectors  10 ,  70  are moved toward each other to insert the tip portions  532  of the plug contact elements  5  into the corresponding passageways  711  of the socket connector  70  as shown in FIG. 10B. A further movement of the connectors  10 ,  70  toward each other brings the tip portions  532  of the plug contact elements  5  into engagement with the mating sections  731  of the socket contact elements  73  as shown in FIG.  10 C. Initially, only a point contact engagement is formed between the tip portion  532  of the plug contact element  5  and the mating section  731  of the socket contact element  73 . 
     Further moving the connectors  10 ,  70  toward each other leads to a deflection of the arcuate portions  531  of the plug contact elements  5  which positions the apexes of the arcuate portions  531  against the internal wall  3  of the plug housing  4  for supporting further deflection of the arcuate portions  531  caused by the movement of the connectors  10 ,  70  toward each other. The deflection of the arcuate portions  531  changes the inclination of the tip portions  532  with respect to the mating sections  731  of the socket contact elements  73  thereby changing the contact engagement from the point contact to a surface contact. 
     During the deflection of the arcuate portions  531 , the tip portions  532  of the plug contact elements  5  slide on the corresponding mating sections  731  of the socket contact elements  73 . The tip portions  532  may be dimensioned to engage with the end faces  711   a  of the passageways  711  after the sliding motion which may result in a firmer engagement between the tip portions  532  of the plug contact elements  5  and the mating sections  731  of the socket contact elements  73 . 
     Eventually, the mating faces  40   a ,  71   a  of the connectors  10 ,  70  overlappingly engage with each other as shown in FIG.  10 D and securely position the tip portions  532  of the plug contact elements  5  against the mating sections  731  of the socket contact elements  73 . 
     In accordance with another aspect of the present invention, the plug connector  10  may engage with a circuit board  8  (FIG. 11A) directly. To accommodate the guide posts  1  of the plug connector  10 , the circuit board  8  is provided with post receiving holes  83  on a substrate board  81  thereof. The circuit board  8  is also provided with conductive pads or traces  82  for electrically engaging with the plug contact elements  5  of the plug connector  10 . 
     As shown in FIG. 11A, the plug connector  10  is positioned with respect to the circuit board  8  with the mating face  40   a  thereof facing the circuit board  8 . The plug connector  10  is moved toward the circuit board  8  to insert the guide posts  1  into the post receiving holes  83  of the circuit board  8  and the tip portions  532  of the plug contact elements  5  engaging with the conductive pads  82  as shown in FIG. 11B. A point contact is formed between each plug contact element  5  and the corresponding conductive pad  82  of the circuit board  8 . 
     Further moving the plug connector  10  toward the circuit board  8  deflects the arcuate portions  531  of the contact elements  5  and the tip portions  532  slide on the conductive pads  82  as shown in FIG.  11 C. Eventually, the mating face  40   a  of the plug connector  10  engages with the circuit board  8  and the arcuate portions  531  of the contact elements  5  are deflected to such an extent that the tip portions  532  are received in the contact receiving channels  31  of the housing  4  and the point contact is changed to a surface contact. 
     Although the present invention has been described with reference to preferred embodiments, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims. For example, as shown in FIG. 9A, the mating section  53  of each plug contact element  5  can be provided with a backward bent extension  534  which engages with the inside face  413  of the side wall  49  of the housing  4  for more securely retaining the plug contact element  5  in position during the deflection of the arcuate section  531  thereof. In addition, as shown in FIG. 9B wherein a further modification of the plug contact element  5  is shown, the backward bent portion  534  is shaped in compliance with an inclined configuration of the inside face  413  of the side wall  49  of the housing  4  for more securely retaining the contact element  5 . Obviously, these and other modifications should be deemed within the scope of the present invention and be protected by the patent issued thereto.