Abstract:
A board-to-board electrical connector includes a male plug having a first insulating body and a plurality of male terminals arranged in rows therein, each male terminal has a protrusion which includes a front guide section and a lower bottom supporting section protruding downwards out of a lower surface of the first insulating body; and a female receptacle correspondingly conducting the male plug, which has a second insulating body and a plurality of female terminals arranged in rows therein, each female terminal is opened with a slide hole, a first wide opening is formed therein for the protrusion to insert, so that the bottom supporting section is lower than the first wide opening, a narrow opening of the slide hole is formed for the front guide section to be pressed therein until the bottom supporting section moves under the narrow opening, so that the protrusion is limited in the slide hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 201120167071.2 filed in China on May 24, 2011, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a board-to-board electrical connector, and more particularly to a low-height surface mount board-to-board electrical connector. 
     BACKGROUND OF THE INVENTION 
     Generally speaking, a printed circuit board is connected to a flexible circuit board through a surface mount board-to-board electrical connector. Usually, a plug welded on the flexible circuit board is engaged with a receptacle welded on the printed circuit board by up and down assembly, so that a contact terminal of the receptacle is electrically connected to a contact terminal of the plug. 
     Referring to China Patent No. 200620167704, a board-to-board electrical connector is disclosed, see FIG. 6 in the filed patent specification. The board-to-board electrical connector is formed by a first connector 1 (i.e., the plug) and a second connector 2 (i.e., the receptacle) connected to the first connector 1 by insertion. The first connector 1 includes a first body 10 and a plurality of first terminals 15. The second connector 2 includes a second body 20 and a plurality of second terminals 25. The first terminal 15 has a U-shaped upper contact portion 152, and an inner slot 1521 and an outer slot 1522 opposite to the inner slot 1521 are formed on the upper contact portion 152. The second terminal 25 has two lower contact portions 252, and the two lower contact portions 252 are respectively formed with bumps 2521. Therefore, when the first connector 1 is inserted into the second connector 2, the bumps 2521 may respectively urge against the inner slot 1521 and the outer slot 1522 to form electrical connection. 
     However, the development of the board-to-board electrical connector is in the trend of thin volume. In consideration of reducing the height of the board-to-board electrical connector, the above board-to-board electrical connector has the following defects. (1) The side surface of the first terminal 15 and the side surface of the second terminal 25 are in contact to form the electrical connection, so if the structure of the board-to-board electrical connector is made to be thinner, when the heights of the first terminal 15 and the second terminal 25 are reduced, it is difficult to maintain a sufficient contact area; (2) the bumps 2521 of the second terminal 25 are caught by the inner slot 1521 and the outer slot 1522 of the first terminal 15, so when the heights of the first terminal 15 and the second terminal 25 are reduced, the design technology of the bumps 2521, the inner slot 1521, and the outer slot 1522 needs to be precise and accurate, and this manner of catching is not reliable and may be easily disengaged. 
     Therefore, it is necessary to design a novel board-to-board electrical connector capable of solving the above problems. 
     SUMMARY OF THE INVENTION 
     In one aspect, the present invention is directed to provide a board-to-board electrical connector with a lower height. 
     In one embodiment, the board-to-board electrical connector of the present invention includes a male plug having a first insulating body and a plurality of male terminals arranged in rows in the first insulating body, in which each male terminal has a protrusion protruding downwards out of a lower surface of the first insulating body, the protrusion has a front guide section and a bottom supporting section lower than the front guide section; and a female receptacle correspondingly conducting the male plug, in which the female receptacle has a second insulating body below the first insulating body and a plurality of female terminals arranged in rows in the second insulating body, a surface of each female terminal is opened with a slide hole, a first wide opening is formed in the slide hole for the protrusion to insert, so that the bottom supporting section is lower than the first wide opening, and a narrow opening of the slide hole is formed by extending from one end of the first wide opening for the front guide section to be pressed into the narrow opening until the bottom supporting section moves to a position under the narrow opening, so that the protrusion is limited in the slide hole. In this manner, the male terminal and the female terminal are conducted. 
     Compared with the prior art, the front guide section of the present invention is pressed into the narrow opening, and each male terminal is clamped by the corresponding slide hole to form a contact state. The bottom supporting section is located below the narrow opening, and the male terminal and the female terminal are in side-pull engagement by way of being parallel to the flexible circuit board instead of the up and down engagement in the prior art. Therefore, the low-height board-to-board electrical connector can be easily fabricated and this clamping manner realizes a reliable connection. 
     These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be effected without departing from the spirit and scope of the novel concepts of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate one or more embodiments of the invention and together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment, and wherein: 
         FIG. 1  is an exploded view of a board-to-board electrical connector in one embodiment of the present invention; 
         FIG. 2  is a three-dimensional view of a male terminal in  FIG. 1 ; 
         FIG. 3  is a top view of the male terminal in  FIG. 1 ; 
         FIG. 4  is a three-dimensional view of a female terminal in  FIG. 1 ; 
         FIG. 5  is a top view of the female terminal in  FIG. 1 ; 
         FIG. 6  is a schematic assembly view of a male plug and a female receptacle in  FIG. 1 ; 
         FIG. 7  is a cross-sectional view of the male plug and the female receptacle in  FIG. 1  in an insertion state; 
         FIG. 8  is a cross-sectional view of the male plug and the female receptacle in  FIG. 1  in a contact state; and 
         FIG. 9  is a top view of the male plug and the female receptacle in  FIG. 1  in the contact state. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the invention are now described in detail. Referring to the drawings, like numbers indicate like components throughout the views. As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. 
     Referring to  FIG. 1 , the board-to-board electrical connector in one embodiment of the present invention includes a male plug  100  and a female receptacle  200  below the male plug  100 . As shown in  FIG. 1 , an X direction is defined to be upwards, a Y direction is defined to be forwards, and a Z direction is defined to be rightwards. In this embodiment, the direction terminologies like up, down, front, rear, left, and right are used for illustrating the structures and operation manners of all components of the board-to-board electrical connector. However, the directions indicated by the terminologies are only used for illustrating the orientation of the board-to-board electrical connector in  FIG. 1 , and when the defined direction of the board-to-board electrical connector changes, the directions indicated by the terminologies will be interpreted into different directions accordingly. 
     The male plug  100  is substantially plate-shaped and includes a first insulating body  1  and a plurality of male terminals  2 . The male terminals  2  are embedded in the first insulating body  1 . The first insulating body  1  has a first abutting surface (not shown) facing the female receptacle  200  and a first welding surface  11  opposite to the first abutting surface. The first insulating body  1  is recessed with two first terminal slots  12 , and each male terminal  2  straddles the first terminal slot  12 , that is, each male terminal  2  is fixed on two opposite sides (for example, in the front and rear directions) of the first terminal slot  12 . 
     The female receptacle  200  may also be substantially plate-shaped and includes a second insulating body  3  and a plurality of female terminals  4 . The female terminal  4  is embedded in the second insulating body  3 . The second insulating body  3  has a second abutting surface  31  facing the male plug  100  and a second welding surface (not shown) opposite to the second abutting surface  31 . The second abutting surface  31  has a first boss  33  and a second boss  34  for confining a moving range of the male plug  100 . The second insulating body  3  has two second terminal slots  35 , and each female terminal  4  straddles the second terminal slot  35 , that is, each female terminal  4  is fixed on two opposite sides (for example, in the front and rear directions) of the second terminal slot  35 . Each female terminal  4  fits the corresponding male terminal  2 . 
     Referring to  FIG. 2  and  FIG. 3 , the male terminal  2  is in an elongated shape, and two ends are respectively a first welding leg  21  and a second welding leg  22  and are respectively fixed on two opposite sides of the first terminal slot  12 . A protrusion  20  is formed between the two welding legs and the protrusion  20  has a bottom supporting section  23  extending downwards, a front guide section  24 , and a rear guide section  26 . 
     The bottom supporting section  23  bends and extends backwards and upwards to form the front guide section  24 , and the bottom supporting section  23  bends and extends frontwards and upwards to form the rear guide section  26 . The bottom supporting section  23  is lower than any one of the first welding leg  21 , the second welding leg  22 , the front guide section  24 , and the rear guide section  26 . The front guide section  24  bends and extends backwards to form a front transition section  25 . The front transition section  25  bends backwards vertically to form the first welding leg  21 . The rear guide section  26  bends forwards to form a rear transition section  27 . The rear transition section  27  bends and extends forwards to form a first bending portion  28 . The first bending portion  28  bends and extends forwards to form the second welding leg  22 . 
     As shown in  FIG. 3 , the width of the rear transition section  27  is gradually expanded near the first bending portion  28 , and the widths of the first bending portion  28  and the second welding leg  22  are the same and greater than the width of the rest part. The width of the bottom supporting section  23  is greater than the widths of the front guide section  24  and the rear guide section  26 . The widths of the front guide section  24 , the rear guide section  26 , and the front transition section  25  are all the same. Referring to  FIG. 6 , the plane of the second welding leg  22  is parallel to the plane of the bottom supporting section  23 , and the front transition section  25  and the rear transition section  27  are coplanar and are parallel to the plane of the bottom supporting section  23 . An end surface of the first welding leg  21  is coplanar with a plane where the second welding leg  22  is located to obtain a good coplanar effect when welded on the flexible circuit board. A part of the first welding leg  21  and the first bending portion  28  are embedded in the first insulating body  1 . 
     Referring to  FIG. 4 , the female terminal  4  is in an elongated shape, and two ends are respectively a third welding leg  41  and a fourth welding leg  42  and are respectively fixed on two opposite sides of the second terminal slot  35 . A middle part of the female terminal  4  is punched to form a slide hole  43 . The slide hole  43  is substantially in an 8 shape, and includes a first wide opening  431 , a front constriction opening  432 , a narrow opening  433 , a rear constriction opening  434 , and a second wide opening  435  sequentially. The first wide opening  431  is gradually reduced towards the narrow opening  433  to form the front constriction opening  432 , and the narrow opening  433  is gradually enlarged towards the second wide opening  435  to form the rear constriction opening  434 . Therefore, the widths of the front constriction opening  432  and the rear constriction opening  434  are gradually varied, and the reducing extents of the front constriction opening  432  and the rear constriction opening  434  are the same. A front block region  44  is formed between the slide hole  43  and the third welding leg  41 , and the front block region  44  bends and extends vertically to form the third welding leg  41 . A rear block region  45  is formed between the slide hole  43  and the fourth welding leg  42 . A second bending portion  46  is formed between the fourth welding leg  42  and the rear block region  45 . Two clamping arms  47  are joint together to form the slide hole  43 , and in the up and down directions defined in  FIG. 1 , the corresponding clamping arm  47  of the narrow opening  433  is arc-shaped. The middle part of the narrow opening  433  has a catch opening  4331 , and the catch opening  4331  is formed by bumps  48  extending oppositely from two clamping arms  47 . 
     Referring to  FIG. 5 , the widths of the first wide opening  431  and the second wide opening  435  are greater than the width of the narrow opening  433 , and the width of the catch opening  4331  is smaller than the width of the rest part of the narrow opening  433 . As shown in  FIG. 6 , an end surface of the third welding leg  41  is coplanar with a plane where the fourth welding leg  42  is located to obtain a good coplanar effect when welded on the printed circuit board. A part of the third welding leg  41  and the second bending portion  46  are embedded in the second insulating body  3 . 
     As shown in  FIG. 1 , the male terminals  2  are fixed in two rows front and back on the male plug  100 . Two rows of the first welding legs  21  are adjacent to each other, and two rows of the second welding legs  22  are far away from each other. Correspondingly, the female terminals  4  are fixed in two rows front and back on the female receptacle  200 . Two rows of the third welding legs  41  are adjacent to each other, and two rows of the fourth welding legs  42  are far away from each other. When the male plug  100  is installed on the female receptacle  200  from the top down, for the female receptacle  200 , the male plug  100  has two states, namely, an insertion state and a contact state. 
     As shown in  FIG. 7 , when the male plug  100  is in an insertion state relative to the female receptacle  200 , as the width of the first wide opening  431  is greater than the width of the bottom supporting section  23 , the bottom supporting section  23  may be embedded in the first wide opening  431 , and the male terminal  2  gets into the female terminal  4  with zero insertion force. Now, the front transition section  25  is located above the front block region  44 , and the rear guide section  26  is located above the front constriction opening  432 . 
     As shown in  FIG. 8  and  FIG. 9 , when the male terminal  2  moves towards the catch opening  4331  until the bottom supporting section  23  moves to a position below the narrow opening  433 , the male plug  100  changes from the insertion state to the contact state relative to the female receptacle  200 . Now, the width of the bottom supporting section  23  is greater than the width of the narrow opening  433 , so the bottom supporting section  23  is clamped by the catch opening  4331 , and in the up and down directions, the male terminal  2  cannot be disengaged from the female terminal  4  from the top. 
     The front guide section  24  is clamped by the front constriction opening  432 , and left and right side surfaces of the front guide section  24  are in interference contact with two opposite inner side surfaces of the front constriction opening  432 . As the widths of the front guide section  24  and the rear guide section  26  are the same and inclined in the same way, the reducing extents of the front constriction opening  432  and the rear constriction opening  434  are the same, when the front guide section  24  is clamped by the front constriction opening  432 , the rear guide section  26  is exactly clamped by the rear constriction opening  434 , and left and right side surfaces of the rear guide section  26  are in interference contact with two opposite inner side surfaces of the rear constriction opening  434 . 
     The bending extent of the arc-shaped clamping arms  47  on two sides of the catch opening  4331  may be designed through calculation to make the upper surface of the bottom supporting section  23  and the lower surface of the female terminal  4  corresponding to the narrow opening  433  form a compression contact. Therefore, in the contact state, the male terminal  2  and the female terminal  4  have six contact points, which are (1) two contact points formed when the left and right side surfaces of the front guide section  24  are in interference contact with the two opposite inner side surfaces of the front constriction opening  432 ; (2) two contact points formed when the left and right side surfaces of the rear guide section  26  are in interference contact with the two opposite inner side surfaces of the rear constriction opening  434 ; and (3) two contact points formed by the upper surface of the bottom supporting section  23  and the lower surface of the deepest recessed position of the corresponding clamping arm  47  of the catch opening  4331 . 
     Alternatively, the first terminal slot  12  may be disposed in a plurality of rows or in a matrix on the first insulating body  1 , and correspondingly, the second terminal slot  35  may be disposed in a plurality of rows or in a matrix on the second insulating body  3 . The electrical connector of the present invention, among other things, has the following advantages. 
     (1) The male terminal  2  is embedded in the first insulating body  1 , the bottom supporting section  23  straddles the first terminal slot  12 , and each male terminal  2  is fixed on two opposite sides of the first terminal slot  12 . In this manner, the male terminal  2  may be securely fixed on the first insulating body  1 . 
     (2) The female terminal  4  is embedded in the second insulating body  3 , and the female terminal  4  is fixed on two opposite sides of the second terminal slot  35 . In this manner, the female terminal  4  may be securely fixed on the second insulating body  3 . 
     (3) In the insertion state, as the width of the first wide opening  431  is greater than the width of the bottom supporting section  23 , the male terminal  2  gets into the female terminal  4  with zero insertion force. In the contact state, the front guide section  24  and the rear guide section  26  are together clamped in the narrow opening  433 , and the clamping force may be adjusted according to the widths of the front guide section  24  and the front constriction opening  432  and the widths of the rear guide section  26  and the rear constriction opening  434  without influencing the insertion force. 
     (4) When the male plug  100  changes from the insertion state to the contact state relative to the female receptacle  200 , the bottom supporting section  23  passes through the front constriction opening  432  and is clamped by the catch opening  4331 . The front guide section  24  is clamped by the front constriction opening  432 , and the rear guide section  26  is clamped by the rear constriction opening  434 . To release the contact state, a larger force needs to be exerted to move the male terminal  2  from the clamping state of the female terminal  4 , so when the insertion state is changed to the contact state until it is hard to pull, the operator may easily understand that it is properly installed. 
     (5) When the male plug  100  and the female receptacle  200  are in a contact state, the bottom supporting section  23  is located below the narrow opening  433 . As the width of the bottom supporting section  23  is greater than the width of the narrow opening  433 , the male terminal  2  will not be disengaged from the female terminal  4  in the upward direction, and the male terminal  2  and the female terminal  4  cannot be disengaged in the up and down directions. 
     (6) Each male terminal  2  is clamped by the corresponding slide hole  43  to form the contact state, and the male terminal  2  and the female terminal  4  are in side-pull engagement by way of being parallel to the flexible circuit board instead of the up and down engagement in the prior art. Therefore, the low-height board-to-board electrical connector can be easily fabricated. 
     The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. 
     The embodiments are chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.