Patent Publication Number: US-6659808-B2

Title: Electrical connector assembly having improved guiding means

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This patent application is a continued-in-part (CIP) application of patent application Ser. No. 09/746,088, filed on Dec. 21, 2000 now U.S. Pat. No. 6,390,857, and a Co-pending Application of Patent Application with an unknown serial number, entitled “ELECTRICAL CONNECTOR HAVING IMPROVED GROUNDING TERMINALS”, invented by the same inventors as this patent application, another co-pending application of application with an unknown serial number, entitled “ELECTRICAL CONNECTOR HAVING PRINTED SUBSTRATES THEREIN ELECTRICALLY CONTACTING CONDUCTIVE CONTACTS THEREOF BY SOLDERLESS”, invented by the same inventors as this patent application; and another co-pending application with an unknown serial number, entitled “ELECTRICAL CONNECTOR HAVING IMPROVED CONTACTS”, invented by Timothy Brain Billman, all assigned to the same assignee and filed on the same date with this application. U.S. Pat. No. 6,375,508 is also related hereto. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electrical connector assembly, and particularly to an electrical connector assembly having improved guiding means for accurately guiding a male connector thereof to mate with a female connector thereof. 
     2. Description of the Related Art 
     Fleck Research, the worldwide leader in information technology and market intelligence, announced an article, entitled “A View from the Backplane”, on Jan. 07, 2002 at the website, http://www.fleckresearch.com/news/en 13 99-10-18.htm. This article introduced some backplane connectors, for example, Teradyne and Molex&#39;s HDM (High Density Metric) family of 2.0 mm connectors, FCI&#39;s (Berg) Metral HB connectors, FCI&#39;s new HMHS (Hard Metric High Speed) connector and AMP&#39;s Z-PACK HS3 connector. These connectors have common features of high-density, high-speed and strict demand for impedance and crosstalk control. 
     U.S. Pat. Nos. 6,171,115 and 6,267,604, both issued to Tyco Electronics Corporation, each disclose a backplane connector including a dielectric housing and a plurality of circuit boards held in the housing. The housing includes a front housing and an organizer engaging with the front housing. Each circuit board provides a plurality of conductive tracks extending from a mating interface thereof to a mounting edge thereof. The mating interface extends beyond the front housing to mate with a mating connector. The mounting edge is secured with conductive terminals by soldering before the mounting edge and the terminals are inserted in slots of the organizer. U.S. Pat. No. 6,083,047, issued to Berg Technology, Inc., discloses an alternate backplane connector including a connector body of dielectric material and a plurality of integrated PCB modules arranged parallel, side-by-side inserted to the connector body. Each PCB module includes a pair of substrates, a plurality of terminals soldered onto an inner surface of each substrate and an insulating spacer sandwiched between the inner surfaces of the substrates. U.S. Pat. No. 6,168,469, issued to Hon Hai Precision Ind. Co., Ltd. discloses a similar backplane connector that the contacts are soldered to printed circuit boards. These connectors have several disadvantages. First, it requires a step of soldering the contacts to the substrates by Surface Mounting Technology (SMT). The SMT requires expensive machine, thereby increasing the manufacturing cost of the connectors. Second, when the substrates, which are originally designed for signal transmission are required to be replaced by substrates for power transmission, the substrates together with the contacts must be discarded. This is not economy. Third, there is no means for guiding contacts of a mating connector to engage with the mating surface of the substrates. Therefore, there is a disadvantage that noble metal plated on contacting portions of the signal contacts may wear off due to their wiping action against the corners of the edge of the substrate. 
     U.S. Pat. Nos. 6,293,827 and 6,174,202, both issued to Teradyne Inc., U.S. Pat. No. 6,343,955, issued to Berg Technology Inc., and U.S. Pat. No. 6,299,484, issued to Framatome Connectors International (FCI), each disclose a backplane connector having a plurality of contacts stamped and formed from metal ribs. Each contact has a mating end for engaging with a contact of a mating connector and a mounting end for mounting to a mother board. These contacts are relatively long and manufactured costly. 
     U.S. Pat. No. 5,980,321, issued to Teradyne Inc., and U.S. Pat. No. 6,220,896, issued to Berg technology Inc., each disclose a backplane connector including a plate between every two rows of signal contacts. One of the disadvantages of these backplane connectors is that the grounding plate has no spring arm for reliably contacting a corresponding grounding element of a mating connector. So, disconnection may happen between the grounding plate of this backplane connector and the grounding element of the mating connector. Hence, an improved electrical connector is required to overcome the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     A first objective of the present invention is to provide an electrical connector having substrates therein moveably engage with corresponding conductive contacts thereof such that it is very convenient to replace some of the substrates with other devices. 
     A second objective of the present invention is to provide an electrical connector having means located in front of substrates thereof for guiding contacts of a mating connector to contact corresponding conductive elements on the substrates. 
     A third objective of the present invention is to provide an electrical connector assembly having an improved guiding means for guiding a male connector thereof to correctly mate with a female connector thereof. 
     A fourth objective of the present invention is to provide an electrical connector having a plurality of contacts that are secured to an insulative member thereof in a unique way. 
     To obtain the above objectives, an electrical connector assembly comprises a male connector mountable to a first printed circuit board, a female connector mountable to a second printed circuit board and a guiding means for guiding the male connector to mate with the female connector correctly. The male connector include first and second individual housing portions engageable with each other, a plurality of substrates held between the firs and the second housing portions and a plurality of signal contacts and a plurality of grounding terminals attached to the second housing portion in face-to-face relationship. Each substrate has a plurality of first conductive pads adjacent a first edge thereof and a plurality of second conductive pads adjacent a second edge thereof which is orthogonal with the first edge. The first housing portion provides a plurality of wedge-shaped lead-in bars in front of the substrates for guiding contacts of the female connector to contact corresponding first conductive pads of the substrates. The second edges of the substrates extend out of the first housing portion into the second housing portion to be removeably sandwiched between correspond signal contacts and corresponding grounding terminals. 
     The female connector includes a dielectric member having a plurality of elongate wafers and defining a channel between every two adjacent wafers, a plurality of signal contacts and a plurality of grounding terminals received in the channels with each grounding terminal confronting several signal contacts. Each grounding terminal has four retention latches and eight contacting arms at one side thereof and five tail portions at an opposite side thereof. The contacting arms are sorted in four pairs and between each pair there is a retention latch. Each retention latch has a cap portion at a top end thereof attached to the dielectric member, thereby retaining the grounding terminals to the dielectric member. The contacting arms are configured to engage with grounding elements of the female connector while the tail portions are configured to electrically contact corresponding conductive pads on the second printed circuit board. In a preferred embodiment, the contacting arms of the grounding terminals are somewhat stronger than the contacting portions of the signal contacts, so, the substrates sandwiched by the contacting arms and the contacting portions are pushed by the contacting arms toward the contacting portions to secure the electrical connection between the contacting portions and the second conductive pads. Retention portions of the signal contacts each define a slot such that the retention portions may straddle upon corresponding protrusions on a bottom surface of the dielectric member. 
     The guiding means includes a pair of frames, which define a chamber between each frame and an outmost lead-in bar of the first housing portion, at opposite ends of the first housing portion and a pair of guiding posts at opposite ends of the dielectric member. The guiding posts are received in corresponding chambers before the first housing portion engages with the dielectric member for guiding the male connector to mate with the female connector. Each frame provides two guiding keys unsymmetrically located in an inner surface thereof and each guiding post defines two guiding cuts in accordance with the guiding keys. The male connector can only mate with the female connector when the guiding keys are accommodated by corresponding guiding cuts, thereby providing anti-blindmating function. 
     Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an assembled perspective view of a male connector and a female connector respectively mounted onto a first and a second printed circuit boards (PCBs); 
     FIG. 2 is a front-top perspective view of the male connector mounted on the first PCB; 
     FIG. 3 is an exploded perspective view of first and second housing portions of the male connector; 
     FIGS. 4A and 4B are enlarged sections of FIG. 3; 
     FIG. 5 is a rear-top perspective view of the first housing portion in FIG. 3; 
     FIGS. 6A-6C are enlarged perspective views of signal contacts of the male connector in three embodiments; 
     FIG. 7 is an enlarged perspective view of a grounding terminal of the male connector; 
     FIGS. 8A-8B are opposite perspective views of a substrate of the male connector; 
     FIG. 9 is a cross-sectional view of a section of the second housing portion and the substrates attached to the second housing portion; 
     FIG. 10 is a top-front perspective view of the female connector mounted on the second PCB; 
     FIGS. 11A-11B are enlarged top and bottom perspective views of a section of the female connector in FIG. 10; 
     FIG. 12 is an enlarged cross-sectional view of a section of the assembly of the male and the female connectors; 
     FIGS. 13A-13B are perspective views of the assembly of the male and female connectors taken from different perspectives, wherein the housings are removed to clearly show the engagement of the substrates with the signal contacts and the grounding terminals; and 
     FIG. 14 is a top planar view of a PCB of an alternative embodiment of this invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1-3,  6 A- 8 B and  10 , an electrical connector assembly  1  of the present invention includes a male connector  10  mounted on a first printed circuit board (PCB)  3  and a female connector  12  mounted on a second PCB  5 . The male connector  10  includes an insulative housing  14 , a plurality of substrates  16  and a plurality of signal contacts  18  and grounding terminals  20  received in the housing  14 . The female connector  12  includes an insulative housing  22 , a plurality of signal contacts  24  and grounding terminals  26  received in the housing  22 . 
     Referring to FIGS. 3-9, the housing  14  includes first and second individual housing portions  28 ,  30  engageable with each other. The first housing portion  28  has a front surface  32  for mating with the female connector  12 , a rear surface  34  and a lower surface  36  in orthogonal with the rear surface  34 . The first housing portion  28  defines a plurality of passageways  38  through the rear surface  34 , the lower surface  36  and terminating at the front surface  32 . The first housing portion  28  provides a row of blocks  40  on a top section of the rear surface  34  and two guiding ribs  42  near opposite ends of the row of blocks  40 . The guiding ribs  42  downwardly extend throughout the height of the rear surface  34  for guiding the first housing portion  28  to accurately engage with the second housing portion  30 . The first housing portion  28  further provides a plurality of lead-in bars  44  near the front surface  32 . Each lead-in bar  44  is wedge-shaped in cross-section for facilitating mating with the female connector  12 . Each lead-in bar  44  provides three branches  46  rearwardly extending into a corresponding passageway  38  for securing the substrates  16  in the passageways  38  of the first housing portion  28 , respectively. The first housing portion  28  again defines a row of notches  48  (FIG. 5) in a middle surface  50  thereof between and parallel with the front and the rear surfaces  32 ,  34  for purpose disclosed in detail below. 
     The second housing portion  30  has a generally sofa-like shape, and includes a rectangular base portion  52  defining a plurality of channels  54  in an upper surface  56  thereof, a backrest portion  58  upwardly extending from a rear edge of the upper surface  56  of the base portion  52  and two elongate stand-offs  60  depending on front and rear edges of a bottom surface  62  of the base portion  52 . Between every two near channels  54  there is an elongate wafer  64  which defines four recesses  66  in the upper surface  56  and provides an embossment  68  in each recess  66 . The base portion  52  provides a row of blocks  70  on a front face  72  thereof for being engageably received in corresponding notches  48  of the first housing portion  28 . The backrest portion  58  defines a row of notches  74  in a top end  76  thereof for engageably receiving corresponding blocks  40  and two guiding tracks  78  at opposite side portions  80  thereof for receiving the guiding ribs  42  of the first housing portion  28 . 
     The signal contact  18  includes a contacting portion  82  for mating with the substrate  16  and a tail portion  84  for mating with the first PCB  3 . The contacting portion  82  offsets a predetermined distance from the tail portion  84  in a traverse direction of the signal contact  18  (FIG.  9 ). The tail portion  84  is a press-fit tail for engageably inserting into a corresponding plated hole  86  of the first PCB  3 . A signal contact  18 ′ according to a second embodiment has an inclined tail portion  84 ′ for pressing against a corresponding conductive pad  88  of a first PCB  3 ′ according to a second embodiment (FIG. 14) of the present invention. A signal contact  18 ″ according to a third embodiment of the present invention includes a contacting portion  82 ″ having two spring arms  90 , a press-fit tail portion  84 ″ and an inclined retention portion  92  between the contacting portion  82 ″ and the tail portion  84 ″. The retention portion  92  defines a slot  94  so that it may straddle upon a bottom surface of the second housing portion  30 . 
     The grounding terminal  20  includes an elongate base portion  96 , five press-fit tail portions  98  downwardly extending from a lower side of the base portion  96  and four retention latches  100  and eight contacting arms  102  upwardly extending from an upper side of the base portion  96 . Beside opposite sides of each retention latch  100 , there are two contacting arms  102 . Each retention latch  100  is generally 7-shaped and has a cap portion  104  at a top end thereof. The cap portion  104  defines an opening  106  for receiving a corresponding embossment  68  of the second housing portion  30 . The substrate  16  provides a first row of first gold fingers  112  on opposite surfaces near a first edge  108  thereof, a second row of second gold fingers  114  on the opposite surfaces near a second edge  110  thereof and a plurality of traces  116  connecting the first gold fingers  112  to corresponding second gold fingers  114 . The first row is perpendicular to the second row. The substrate  116  defines three grooves  118  in the first edge  108  for engageably receiving corresponding branches  46  of a corresponding lead-in bar  44 . 
     Upon the assembling of the male connector  10 , the substrates  16  are inserted into corresponding passageways  38  of the first housing portion  28  from the rear surface  34  toward the front surface  32 . The first edge  108  of each substrate  16  is hidden behind a corresponding lead-in bar  44  with the grooves  118  thereof engageably receiving corresponding branches  46 . The second edge  110  of each substrate  16  partially extends downwardly beyond the lower surface  36  with the second gold fingers  114  exposing out of the first housing portion  28 . The signal contacts  18  and the grounding terminals  20  are inserted into corresponding channels  54  of the second housing portion  30  with eight signal contacts  18  lying in one side of the channel  54  and one grounding terminal  20  lying in an opposite side of the channel  54  such that the signal contacts  18  confront the grounding terminal  20 . The cap portion  104  of the grounding terminal  20  is received in a corresponding recess  66  with the opening  106  thereof fixedly receiving a corresponding embossment  68 , thereby attaching the grounding terminals  20  to the first housing portion  28 . The first housing portion  28  together with the substrates  16  are then assembled to the second housing portion  30  such that the second edges  110  of the substrates  16  are received in corresponding channels  54  of the second housing portion  30 . The contacting portions  82  of the signal contacts  18  and the contacting arms  102  of the grounding terminals  20  wipe along and electrically contact corresponding second gold fingers  114  of the substrates  16 . The second edge  110  of the substrate  16  is sandwiched between the contacting portions  82  of the signal contacts  18  and the contacting arms  102  of the grounding terminal  20 . The contacting arms  102  are somewhat stronger than the contacting portions  82  such that the second edge  110  is pushed by the contacting arms  102  toward the contacting portions  82  to ensure electrical connections between the second gold fingers  114  and the contacting portions  82  of the signal contacts  18  (FIG.  9  and FIGS.  13 A- 13 B). 
     Referring to FIGS. 10,  11 A and  11 B, the housing  22  of the female connector  12  provides a plurality of elongate wafers  120  and defines a plurality of channels  122  each between two near wafers  120 . Each channel  122  receives eight signal contacts  24  and a grounding terminal  26  at opposite sides thereof. The signal contact  24  and the grounding terminal  26  of the female connector  12  are respectively similar to the signal contact  18 ″ and the grounding terminal  20  of the male connector  10  in structure but different in dimensions. The housing  22  provides a pair of elongate stand-offs  124  and a pair of guiding poles  126  (only one is shown in FIG. 11B) on a bottom surface  128  thereof. The housing  22  further provides a plurality of protrusions  130  on the bottom surface  128 . The signal contact  24  includes an inclined retention portion  132  having a pair of ribs  134  and defining a slot  136  between the ribs  134 . The retention portion  132  straddles on the protrusion  130  with the ribs engageably sandwiching the protrusion  130 , thereby assisting retaining the signal contact  24  to the housing  22 . 
     Referring to FIGS. 12 and 13A,  13 B, when the male connector  10  mates with the female connector  12 , the wedged lead-in bars  44  of the male connector  10  push the contacting portions of corresponding signal contacts  24  and the contacting arms of corresponding grounding terminals  26  to move away from each other so that they may smoothly slide to electrically contact corresponding first gold fingers  112  without wiping against corners of the first edges  108  of the substrates  16 . Therefore, a disadvantage that noble metal plated on the contacting portions  82  of the signal contacts may wear off due to their wiping action against the corners of the edge of the substrate  16  can be prevented in the present invention. The tail portions  84 ,  98  of the signal contacts  18  and the grounding terminals  20  of the male connector  10  arranged in a same row are inserted into a same row of plated holes  86  of the first PCB  3 . So does the female connector  12 . 
     Referring to FIG. 14, in accordance with the signal contacts  18 ′ of the second embodiment, the first PCB  3 ′ of the second embodiment provides five rows of plated through-holes  86 ′ and four pairs of rows of conductive pads  88 , each pair being located between every two near rows of plated through-holes  86 ′. When the male connector  10  is mounted onto the first PCB  3 ′, the tail portions  98  are received in corresponding through-holes  86 ′ by press-fit while the tail portions  84 ′ of the signal contacts  18 ′ electrically contact corresponding conductive pads  88  by a depressing force acting on the tail portions  84 ′. 
     As is shown in FIGS. 1,  2  and  10 , the connector assembly  1  includes a pair of guiding means  138  at opposite sides thereof for guiding the male connector  10  to correctly mate with the female connector  12 . Each guiding means  138  includes a frame  140  at each side of the first housing portion  28  and a chamber  142  between the frame  140  and an near lead-in bar  44 . The frame  140  provides two guiding keys  144  located on an inner surface  146  thereof and extending in a front-to-rear direction. Each guiding means  138  also includes a guiding post  148  at each side of the housing  22  with a wedged top portion  150  extending beyond a top face of the housing  22 . The guiding post  148  defines two guiding cuts  152  unsymmetrically in an outer surface  154  thereof, located corresponding to the guiding keys  144 . When the male connector  10  mates with the female connector  12 , the wedged top portions  150  are first inserted into corresponding chambers  142  and the guiding keys  144  are received in corresponding guiding cuts  152  before the lead-in bars  44  touch the housing  22 , the signal contacts  24  and the grounding terminals  26 . When the guiding posts  148  are wholly received in the corresponding chambers  142 , the male connector  10  securely mates with the female connector  12 . 
     Comparing with the prior arts, this invention has a lot of advantages. First, since the substrates  16  are removeably held in the first housing portion  28 , it is very convenient to replace any one of the substrates  16  with another substrate for a different function. Second, since the first edges  108  of the substrates  16  are covered by the lead-in bars  44 , plated noble metal on the contacting portions  82  of the signal contacts  18  can obtain a better protection against wearing. Third, the elongate grounding terminals  20  each are attached to the second housing portion  30  by four retention latches  100 , the grounding terminals  20  can be securely attached to the second housing portion  30 . Fourth, since the substrates  16  are pushed by the grounding terminals  20  toward the signal contacts  18 , secure electrical connections are established between the conductive pads  114  and the contacting portions  82  of the signal contacts  18 . 
     It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.