Abstract:
A connector assembly ( 100 ) includes a first connector ( 10 ) and a mating second connector ( 30 ). Each connector includes a number of leadframes ( 21, 41 ) stacked one by one. Each leadframe has a first leadframe housing ( 211, 411 ) and a second leadframe housing ( 214, 414 ) attached to the first leadframe housing. Each connector includes an array of first terminals ( 5 ) and an array of second terminals ( 6 ) respectively mounted along the second and the first leadframe housings, and a pair of latching members ( 25, 45 ) mounted at opposite sides of the leadframes together with the first and second terminals to tie the plurality of stacked leadframes as a whole.

Description:
This patent application is a continuation-in-part of a pending U.S. patent application Ser. No. 12/148,757 filed Apr. 22, 2008, entitled “HIGH DENSITY CONNECTOR HAVING TWO-LEVELED CONTACT INTERFACE”, which is invented by the same inventor as this patent application and assigned to the same assignee with this application. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a high density connector and particularly to a connector assembly utilizing such high density connectors to create a unique connection interface. 
   2. Description of Related Art 
   In card edge connectors, it is known to arrange contacts in two levels. U.S. Pat. No. 5,052,936 issued on Oct. 1, 1991 to Biechler et al. exemplifies a connector. In this design, two arrays of aligned contact members for interfacing either side of a board or card edge are insert molded to a lower subassembly housing which in turn is assembled to an upper housing. The board or card edge is provided with an upper level of contact pads and a lower level of contact pads. When the board or card edge is inserted into the housing, the lower level of contact pads electrically connect with a first array of contact members of the connector and the upper level of contact pads electrically connect with a second array of contact members. 
   The contact member is disposed in an unforced status when the card edge is not inserted into the housing. The contact member would tilt to contact with the contact pads of the card edge, when the card edge is inserted into the housing. When the card edge is inserted into or pulled out from the housing for many times, the contact member would become less resilient to thereby have an unreliable engagement between the card edge and the housing. 
   U.S. Pat. No. 6,371,773 issued on Apr. 16, 2002 to Crofoot et al. discloses a high density interconnect system used in association with printed circuit boards, circuit cards, back panels and other like substrates. The interconnect system comprises electrical connector modules each having a plurality of signal conductors substantially parallel within a first plane and a reference conductor element made of a single piece of sheet metal. The reference conductor element includes a plurality of first reference conductors substantially parallel to one another and interspersed between the signal conductors and at least part of which are in the first plane and a plurality of second reference conductors within a second plane which is offset from and substantially parallel to the first plane. The second reference conductor is aligned with the signal conductor in a direction perpendicular to the plane of the connector module. However, when the connector modules of two mating connector portions are mated, curved contact ends of mating signal conductors make a hermaphrodite mating while associated second reference conductors only shield beside the mated signal conductor but not touch each other. 
   The signal conductors and the reference conductors are respectively inserted on one plane to combine themselves as a whole. When it is needed to choose a certain number of conductors, it is not convenient to insert proper number of conductors into the plane, or remove the redundant conductors one by one. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a connector assembly comprises a first connector and a mating second connector. Each connector includes a number of leadframes stacked one by one. Each leadframe has a first leadframe housing and a second leadframe housing attached to the first leadframe housing. Each connector includes an array of first terminals and an array of second terminals respectively mounted along the second and the first leadframe housings, and a pair of latching members mounted at opposite sides of the leadframes together with the first and second terminals to tie the plurality of stacked leadframes as a whole. The leadframe has a shelf between said two arrays of first and second terminals. The first terminal has a tip end resisting against an inner surface of the shelf. The first terminal and the second terminal of said two connectors come to contact with each other and the tip end of the first terminal leaves away from the shelf, when the first and second connectors are mated with each other. 
   The plurality of leadframes are stacked one by one to optimize the space usage. The plurality of stacked leadframes are tied as a whole via the latching member. It isn&#39;t necessary to fix the leadframes in virtue of a housing and it is easy to assemble proper number of leadframes in accordance with different requires. Additionally, the tip end of the first terminal resists against an inner surface of the shelf and the shelf provides a pre-loaded force to the first terminal when the first terminal is not mating with corresponding second terminal. The first terminal could engage with corresponding second terminal reliably, since it has been pre-loaded. 
   Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded perspective view of a connector assembly in accordance with the present invention; 
       FIG. 2  is another exploded perspective view similar to  FIG. 1 , taken from another aspect; 
       FIG. 3  is a perspective view showing an assembled female connector not mating with an assembled male connector; 
       FIG. 4  is another perspective view showing the assembled female connector not mating with the assembled male connector, taken from another aspect; 
       FIG. 5  is an assembled perspective view of the connector assembly as shown in  FIG. 1 ; 
       FIG. 6  is another assembled perspective view of the connector assembly as shown in  FIG. 5 , taken from another aspect; 
       FIG. 7  is a partially exploded view of a female terminal module; 
       FIG. 8  is a partially exploded view of a male terminal module; 
       FIG. 9  is an enlarged perspective view showing a female terminal pair mating with a male terminal pair; 
       FIG. 10  is a schematic view showing the female terminal pair mating with corresponding male terminal pair; 
       FIG. 11  is a front view showing the first and second terminals arranged along a leadframe, with the leadframe being removed; 
       FIG. 12  is a schematic view showing a movement of the first terminal during a mating process; 
       FIG. 13  is another perspective view of the leadframe as shown in  FIG. 7 ; and 
       FIG. 14  is a perspective view of the female connector, with the female insulative housing having another height. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made to the drawing figures to describe the present invention in detail. Referring to  FIGS. 1-6 , a high density mezzanine connector assembly  100  in accordance with the preferred embodiment of the present invention comprises a first connector  10  and a second mating connector  30 . The first connector  10  is shown as a female connector in view of its housing structure and will be so called in the following description. Similarly, since the second connector  30  is shown as a male connector in view of its interface housing structure, it will be so called in the following description for ease of reference and clarity, but not in the sense of limiting. 
   Referring to  FIGS. 1-4 , the female connector  10  comprises a rectangular female insulative housing  1  defining a receiving cavity  11 , a plurality of female terminal modules  2  arranged in two groups in the receiving cavity  11  of the female insulative housing  1  and a plurality of first latching members  25 . The female insulative housing  1  is formed with a bottom wall  12 , a pair of primary walls  14  and a pair of periphery walls  13  extending upwardly from the bottom wall  12  for surrounding the receiving cavity  11 . The bottom wall  12  defines thereon two groups of channels  121 , and a middle wall  15  between the two groups of channels  121 . The bottom wall  12  has four second slots  122  each defined alongside the periphery wall  13  or middle wall  15 . Optionally, the bottom wall  12  could define only one group of channels  121  and the middle wall  15  would be removed. 
   In conjunction with  FIG. 7 , each female terminal module  2  comprises a female plate  21  having two leadframe housings  211 ,  214  and an array of female terminal pairs  22  mounted along the leadframe housings  211 ,  214 . The leadframe housing  211  has a plurality of terminal recesses  216  for accommodating the first terminals  5 . Such leadframe housing  211  has a pair of first slots  212  symmetrically defined at two opposite ends thereof.  FIG. 13  shows a rear face of the leadframe housing  211  defining a plurality of pin holes  218 . The leadframe housing  214  has a pair of ear portions  2141  formed at opposite ends thereof. Each ear portion  2141  defines a slit  2142  aligned with the first slot  212  of the leadframe housing  211 . In conjunction with  FIG. 9 , each female terminal pair  22  has a first terminal  5  retained to the leadframe housing  214  and a second terminal  6  retained to the leadframe housing  211 . The pin holes  218  support the second terminals  6  during insert molding. The leadframe housing  211  is formed with a shelf  8  across the pin holes  218 . 
   Referring to  FIGS. 1-2 , the first latching member  25  comprises a body portion  251  insertable in the second slot  122  of the female insulative housing  1 , and a bending portion  252  bending from the body portion  251  and insertable into the first slot  212  of the female plate  21 . The bending portion  252  defines a plurality of cutouts  253  engageable with the first slot  212  of the female plate  21 . 
   The male connector  30  comprises a male insulative housing  3  defining a receiving cavity  31  and a plurality of male terminal modules  4  retained to the housing  3  in the retaining cavity  31 . The female and male terminal modules  2  and  4  are similarly constructed, at least as to their mating interface, as will be detailed later. The male insulative housing  3  also has a configuration similar to the that of the female insulative housing  1  and comprises a base or bottom wall  32  and a pair of side walls  33 . The bottom wall  32  defines two groups of channels  321  and a plurality of second slots  322  along the side walls  33  and middle wall  35 . 
   In conjunction with  FIG. 8 , each male terminal module  4  comprises a male plate  41  having two leadframe housings  411  and  414  and a plurality of male terminal pairs  42  mounted along the leadframe housings  411 ,  414 . The leadframe housing  411  has a configuration similar to that of the leadframe housing  211  and comprises a pair of first slots  412 . The leadframe housing  414  has a pair of ear portions  4141  formed at opposite ends thereof. Each ear portion  4141  defines a slit  4142  aligned with the first slot  412  of the leadframe  411 . In conjunction with  FIG. 9 , each male terminal pair  42  has a first terminal  5  retained to the leadframe housing  414  and a second terminal  6  retained to the leadframe housing  411 . 
   In conjunction with  FIGS. 9 and 10 , the first terminal  5  and the adjacent second terminal  6  in a same connector are formed as a female terminal pair  22  or a male terminal pair  42 . Each female terminal pair  22  and each mating male terminal pair  42  are hermaphroditic relative to each other. The first terminal  5  and the mating second terminal  6  is formed as a signal terminal pair  7 . The first terminal  5  comprises a contact portion  51  having a curved mating face, a terminating end  52 , and a contact beam  53  connecting the contact portion  51  and the terminating end  52 . The contact beam  53  comprises a first and a second angled portion  531 ,  532  angled toward the second terminal  6  in one signal terminal pair  7  and an intermediate portion  533  between the first and second angled portions  531 ,  532 . 
   The second terminal  6  comprises a connecting portion  61  having a flat mating face, a terminating end  62 , and a connecting beam  63  connecting the connecting portion  61  and the terminating end  62 . The connecting beam  63  has the first and second angled portions  631 ,  632  and an intermediate portion  633  between the first and second angled portions  631 ,  632 . The second angled portion  632  is angled along a second direction perpendicular to a mating direction to form itself as a Z-shape, and the first angled portion  631  is bent along a third direction orthogonal to the mating direction and the second direction to form itself as a U-shape. Along the mating direction, the connecting portion  61  and the terminating end  62  are aligned with each other and the intermediate portion  633  is not aligned with connecting portion  61 , via the first and second angled portions  631 ,  632 . 
   Referring to  FIGS. 7-11 , the first and second terminals  5  and  6  are preferably retained to associated leadframe housings  211 ,  214  by insert molding. The second terminals  6  are mounted along their leadframe housing  211 . The connecting beam  63  of the second terminal  6  is embedded in a leadframe housing  211  of the female plate  21 , with the connecting portion  61  exposed to the outside. The first terminals  5  are embedded in the leadframe housing  214 . The two leadframe housings  211 ,  214  may be suitably mounted together, for example, through pegs  215  and holes. The first terminals  5  are received in the terminal recesses  216 . The connecting beam  63  of the second terminal  6  has a length longer than that of the contact beam  53  of the first terminal  5  to position the connecting portion  61  forwardly of the contact portion  51  within each female or male terminal pair  22 ,  42 . The shelf  8  is disposed between the array of first terminals  5  and the array of second terminals  6 . In conjunction with  FIGS. 11 and 12 , the tip end  54  of the first terminal  5  resists against the inner surface of the shelf  8 . The first terminals  5  are pre-loaded via the shelf  8 . The intermediate portion  533  of the first terminal  5  and the intermediate portion  633  of the second terminal  6  are staggered with each other within a same connector. The terminating end  52  of the first terminal  5  has a soldering portion leveled with a soldering feet of the terminating end  62  of the second terminal  6  in each female terminal module  2  ( FIG. 12 ). Each terminating end  52 ,  62  of the first, second terminal  5 ,  6  has a soldering ball connected therewith. The assembly of the male terminal module  4  is same to that of the female terminal module  2 . 
   Referring to  FIGS. 1-4 , in assembling of the female connector  10 , the bending portion  252  of the first latching member  25  is inserted in the first slot  212  and the slit  2142  of the female plate  21  to tie all of the female plates  21  together, with the cutouts  253  engaging with the first slot  212  and the slit  2142 . The female terminal modules  2  are inserted into the receiving cavity  11  of the female insulative housing  1 , with a bottom of the leadframe housing  211  inserted in the channels  121  and other part of the leadframe housing  211  retained in the receiving cavity  11 . The body portion  251  of the first latching member  25  is inserted in the second slot  122  of the female insulative housing  1 . The female terminal modules  2  are fixed in the female insulative housing  1  via the first latching member  25 . 
   In assembling of the male connector  30 , the male plates  41  are tied together via the second latching member  45 . The male terminal modules  4  are inserted into the retaining cavity  31  of the male insulative housing  3 . The assembly of male connector  30  is same to that of the female connector  10 . 
   When the male connector  30  is mated with the female connector  10  along the mating direction, the male insulative housing  3  is partially entering the receiving cavity  11  of the female connector  10 , with the female terminal modules  2  inserted into the retaining cavity  31 . The female terminal pairs  22  and corresponding male terminal pairs  42  come to mate with each other, with the curved mating face of the first terminal  5  sliding along and mating the flat mating face of corresponding mated second terminal  6 . The contact portion  51  of the first contact  5  inclines inwardly, with the tip end  54  moving away from the shelf  8  ( FIG. 12 ). 
   In conjunction with  FIGS. 9 and 10 , when the female terminal pair  22  is mated with corresponding male terminal pair  42 , the first terminal  5  is substantially aligned with corresponding mated inverted second terminal  6 , with the contact portion  51  of the first terminal  5  in contact with the inverted connecting portion  61  of the second terminal  6  at a first position A, and with the connecting portion  61  of the second terminal  6  in contact with the contact portion  51  of corresponding mated inverted first terminal  5  at a second position B. The first position A and the second position B are disposed at two different levels and are substantially aligned with each other along the mating direction. The contact portion  51  of the first terminal  5  of the female connector  10  and the contact portion  51  of the first terminal  5  of the male connector  20  are partially overlapped along the mating direction, and are spaced apart along a transverse direction perpendicular to the mating direction. As can be understood, the mating first and second terminals from the two mating modules can be suitably designated as either signal or ground contacts as desired. 
   The contact portion  51  of the first terminal  5  and the connecting portion  61  of corresponding mated second terminal  6  of the signal terminal pair  7  are presented to mate each other. Also, the mating face of the contact portion  51  of the first terminal  5  and the mating face of the connecting portion  61  of the second terminal  6  in a signal terminal pair  7  face toward a same direction. A transverse distance between the first position A and the second position B is smaller than a transverse distance between a lower end of the contact beam  53  and a lower end of the adjacent connecting beam  63 . The contact and connecting portions  51 ,  61  of the first and second terminals  5 ,  6  of the signal terminal pair  7  extend toward a same direction. The soldering portions  52  and the soldering feet  62  extend toward a same direction in a same connector, and extend toward opposite directions in the female and male connectors  10 ,  30 . The soldering portions  52  and soldering feet  62  has a plurality of soldering balls provided thereon for soldering. When the soldering portions  52  and soldering feet  62  are soldered with soldering balls, the first and second latching members  25 ,  45  could work as a heat sink. 
   The contact portion  51  of the female terminal pair  22  comes to contact with the connecting portion  61  of the male terminal pair  42  at the first position A. The connecting portion  61  of the female terminal pair  22  comes to contact with the contact portion  51  of the male terminal pair  42  at the second position B. Two electrical paths have been established; one electrical path may be used for grounding and the other may be used for transferring signal. The first position A and the second position B are disposed at two different levels and are substantially aligned with each other along the mating direction so that the space taken up in such contact interface arrangement will not extend beyond to occupy the space intended for adjacent modules. Therefore, the space occupied by the hermaphroditic terminals, i.e., first and second terminals, has been made of efficient use. 
   Referring to  FIG. 15 , the female insulative housing  1  of the female connector  10  could be designed into a greater height. The stack height of the connector assembly  100  is determined by the height of the female insulative housing  1 . 
   The disclosure is illustrative only, changes may be made in detail, especially in matter of shape, size, and arrangement of parts within the principles of the invention.