Abstract:
A card edge connector and a card edge assembly that utilizes the individual card end connectors are disclosed. The card edge connectors have slotted insulation displacement terminals to connect to wires. Each electrical connector has a housing with first mounting project extends from a first sidewall of the housing and a mounting recess extends from an oppositely facing second sidewall. The mounting projection is dimensioned to be received in the mounting recess of a second electrical connector, thereby allowing the connectors to be mounted to each other. This type of connector assembly allows the connector assembly to be built according to the needs of the end user. This modular aspect of the connector assembly adds flexibility while reducing the overall cost of manufacture. In addition, the use of the slotted insulation displacement terminals further enhances the flexibility of the connector assembly, as various wiring schemes can be effectively and cost efficiently utilized.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a card edge insulation displacement connector. More particularly, the present invention is directed to a card edge insulation displacement connector that has dual slotted terminals and which can be combined to form a card edge connector assembly. 
   BACKGROUND OF THE INVENTION 
   With the decreasing size of electronic devices used in most all fields, there is a continuing demand for smaller sized electrical components used in these electronic devices. This is especially so in the telecommunications field with the demand for mobile, lightweight and smaller sized devices. Similarly, in the field of cable communications, smaller sized electronic devices and the related connectors are in demand. For example, the household use of cable communications, both for television and computer connections, is one area where the need for smaller sized and reliable connectors is rapidly expanding. 
   In the telecommunications field, and more specifically in the cable communications field, insulation displacement contacts (IDCs) are used to quickly and reliably connect wires to a printed circuit board, a junction or distribution box or other devices. The IDC allows the user to connect the wire without the need for first removing the insulation from the wire end. That is, the IDC cuts through the insulation, when the wire is seated in the IDC, to make electrical connection. This ease of making wire connections, especially out in the field, makes the IDC a very useful component. 
   Example prior art IDCs include those disclosed in U.S. Pat. No. 6,168,478 B1, for a Snap Type Retention Mechanism For Connector Terminals issued to Daoud; U.S. Pat. No. 6,159,036, for a Locking Latch Mechanism For An Insulation Displacement Connector, also issued to Daoud; and U.S. Pat. No. 6,165,003, for an Electrical Connector With Variable Thickness Insulation-Piercing Contact Member issued to Bigotto. As shown and described in each of these patents, the IDC generally has a conducting terminal with a pair of beams such that when the wire and insulation is forced between the beams and the beams&#39; edges cut through the wire insulation and make electrical contact with the wire. 
   Other example prior art IDCs are shown in U.S. Pat. Nos. 6,152,760 and 6,406,324 B1. The devices are an IDCs having pivoting wire stuffer elements or wire stuffers. The wire stuffers each have wire slots and are pivotable over the IDC terminal beams. With the wire stuffer in an open position, the wire (not shown) may be placed into the wire slot. When the wire stuffer is then forced into the closed position, with the wire in the wire stuffer slot, the terminal beams cut through the wire insulation and the wire is electrically connected to the terminal. The wire slot diameter is fabricated to accept a limited range of wire sizes. In the telecommunications field, the wire gauge may be between 22 AWG and 26 AWG. 
   While IDCs are very useful, IDC technology has been limited on printed circuit board for use with connectors that employ traditional through hole mount or surface mount technology. In a typical configuration with the IDC assembled on a circuit board, the pivotable wire stuffers tend to be difficult to operate without damaging other components, particularly when the circuit board has closely spaced components due to space requirements. Ease of use of this type of IDC would be greatly enhanced if the pivoting wire stuffers could be positioned at the edge of the circuit board. In addition, the positioning of the IDC connector on the edge of the circuit board would provide increased utilization of the circuit board, allowing other components to be mounted on the top and bottom surfaces thereof. 
   Accordingly, there remains a need for an IDC connector which can be mounted on the circuit board edge surface, thereby allowing for ease of assembly of the IDC connector to the circuit board and ease of termination of the wires in the IDC connector. Additionally, as space on the surface of the printed circuit board is many times at a premium, mounting the IDC connector on the edge of the circuit board allows other component to be mounted on the surface of the printed circuit board in the space previously occupied by the IDC connector and provides for a separable and distinct interface, removed from the components mounted on the face of the printed circuit board. 
   SUMMARY OF THE INVENTION 
   The invention is directed to a card edge connector which is connected to an edge of a circuit board and which also uses insulation displacement terminals to connect to wires. The card edge connector has a housing with a wire receiving face and a board receiving face. Terminal receiving cavities extend from proximate the wire receiving face toward the board receiving face. A board receiving slot extends from the board receiving face toward the terminal receiving face. Terminals are positioned in the terminal receiving cavities. The terminals have insulation displacement sections proximate the wire receiving face and board engagement sections that extend from the terminal receiving cavities into the board receiving slot. The board receiving slot is dimensioned to receive an edge of circuit board therein. The terminals may have insulation displacement slots provided thereon, which can allow two or more wires to be terminated to respective insulation displacement slots thereby allowing for special wire schemes. 
   The card edge connector may also include a wire stuffer cap movably mounted to the housing. The wire stuffer cap may initially be provided in an open position to allow wire to be inserted into the wire stuffer cap. The wire stuffer cap may be moved to a second position, which forces the wires into respective insulation displacement slots, causing the wires and the terminals to be placed in electrical engagement. 
   The invention is also directed to an electrical connector that has a housing and terminals positioned in terminal receiving cavities of the housing. The housing has first mating face and a second mating face. A first mounting project extends from a first sidewall of the housing and a mounting recess extends from an oppositely facing second sidewall. The mounting projection is dimensioned to be received in the mounting recess of a second electrical connector, thereby allowing the connectors to be mounted to each other. The first mounting projection may have an upper wall and a lower wall; the upper wall and the lower wall are sloped toward each other as the upper and lower walls near the first sidewall. The mounting recess has second mounting projections that define the mounting recess. The second mounting projections have sloped walls adjacent the mounting recess, the sloped walls slope away from each other as the sloped walls near the second sidewall. The first mounting projection of the card edge connector is configured to be moved into a mounting recess of a respective second card edge connector, such that the upper wall and the lower wall of the first mounting projection cooperate with the sloped walls of the second mounting projections to retain the first mounting projection of the card edge connector in a respective mounting recess of the respective second card edge connector. 
   The invention is also directed to an electrical connector assembly which has at least two electrical connectors that are connected together to form the assembly. The connectors have housings with first mating faces, second mating faces, and terminal receiving cavities that extend from proximate the first mating faces toward the second mating faces. First mounting projections extend from first sidewalls of the housings and mounting recesses are provided on oppositely facing second sidewalls. The mounting projection of one electrical connector is positioned in the mounting recess of a second electrical connector, the first mounting projection and the mounting recess cooperate to maintain the electrical connectors in position relative to each other, thereby forming the electrical connector assembly. 
   This type of connector assembly allows the connector assembly to be built according to the needs of the end user. As electrical connectors can be mounted together to form any length connector assembly, only one type and size of electrical connector needs to be tooled and manufactured. This modular aspect of the connector assembly adds flexibility while reducing the overall cost of manufacture. The use of card edge connectors that utilize insulation displacement termination methods is also advantageous. As board space is always at a premium, the ability to terminate wires to a connector mounted at the edge of a circuit board has significant cost savings, as a smaller board can be used without effecting the operation of the components. In addition, the use of dual slotted insulation displacement terminals further enhances the flexibility of the connector assembly, as various wiring schemes can be effectively and cost efficiently utilized. 
   Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a card edge connector with a stuffer cap in an open position according to the present invention. 
       FIG. 2  is a back perspective view of the card edge connector of  FIG. 1 . 
       FIG. 3  is a front perspective view of the card edge connector with terminals and the stuffer cap exploded therefrom. 
       FIG. 4  is a front perspective view of the card edge connector with wires terminated thereto and the stuffer cap in a closed position. 
       FIG. 5  is a front perspective view of the card edge connector with wires and a circuit board terminated thereto. 
       FIG. 6  is a bottom perspective view of a series of card edge connectors joined together prior to the insertion of the circuit boards therein. 
       FIG. 7  is a cross-sectional perspective view of the card edge connector with the wires terminated therein. 
       FIG. 8  is a cross-sectional perspective view of the card edge connector with the wires and circuit board terminated therein 
       FIG. 9  is an enlarged front view of a mating portion of two card edge connectors. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As shown in  FIGS. 1 and 3 , a card edge connector  2  has a housing  10 , terminals  50  and a stuffer cap  70 . While the embodiment shown has two terminals  50  and one stuffer cap  70  installed in the housing  10 , other size housings with different numbers of terminals and different size and numbers of stuffer caps can be substituted without departing from the scope of the invention. 
   Housing  10  is made of plastic or other similar material that is nonconductive and has the strength and moldability characteristics required. Housing  10  has a wire receiving face  12 , a card or circuit board receiving face  14 . Top wall  16 , bottom wall  18 , sidewall  20  and sidewall  22  extend between the wire receiving face  12  and the board receiving face  14 . A latching projection  23  extends from the wire receiving face  12 . Terminal receiving cavities  24  ( FIGS. 7 and 8 ) extend from the wire receiving face  12  toward the board receiving face  14 . As shown in  FIGS. 1 ,  3 ,  7  and  8 , a dividing wall  26  is positioned between the terminal receiving cavities  24 . Referring to  FIGS. 7 and 8 , a card or board receiving slot  28  extends from the board receiving face  14  towards the wire receiving face  12 . The board receiving slot  28  extends from proximate the sidewall  20  to proximate the sidewall  22 . A cap receiving cavity  30  ( FIG. 3 ) extends from the wire receiving face  12  toward the board receiving face  14  and from the top wall  16  to the terminal receiving cavities  24 . A pivot cavity  44  is provided proximate the cap receiving cavity  30 . The pivot cavity  44  has a seating projection or lip  46  which extends therein. 
   As best shown in  FIGS. 4 and 9 , sidewall  20  has an elongate first mounting projection  32  which is essentially parallel to the bottom wall  18  and which extends from proximate the wire receiving face  12  toward the board receiving face  14 . The first mounting projection  32  has an upper wall  34  ( FIG. 9 ) and a lower wall  36  which are sloped toward each other as the walls  34 ,  36  near the sidewall  20 . This shape of the first mounting projection  32  is generally referred to as a dovetail in the wood working industry. Sidewall  22  has two elongate second mounting projections  38  that are also essentially parallel to the bottom wall  18  and which extend from proximate the wire receiving face  12  toward the board receiving face  14 . The second mounting projections  38  form a mounting recess  40  therebetween for receiving a corresponding first mounting projection  32  therein, as will be more fully discussed below. The second mounting projections  38  have sloped internal walls  42  which are sloped away from each other as the walls  42  near the sidewall  22 . While the dovetail type configuration is shown, other types of shapes and configurations of the first and second mounting projections can be used. For example, the first mounting projection may have arcuate surfaces on the upper wall and lower walls which cooperate with corresponding arcuate surfaces of the walls of the second mounting projections 
   As best shown in  FIG. 3 , terminals  50  have insulation displacement sections  52  at one end and card or circuit board engagement sections  54  at the other end. In the embodiment shown, each insulation displacement section  52  has two slots  56  which extend inward from the ends of terminals  50 . The slots  56  are dimensioned to cooperate with one or more wires  94  inserted therein. However, while two slots are shown, each insulation displacement section may have one, three, or any other number of slots depending upon the number of wires to be terminated to each terminal. Extending from insulation displacement sections  52  at essentially ninety degrees therefrom are mounting sections  58 . Mounting sections  58  have retention barbs  60  which are dimensioned to engage and displace material of the housing  10  around the terminal receiving cavities  24  to create an interference fit to retain the mounting sections  58  and the terminals  50  in the terminal receiving cavities  24  of the housing  10 . Circuit board engagement sections  54  extend from mounting sections  58  and are bent back toward the insulation displacement sections  52 , such that circuit board engagement sections  54  have resilient characteristics. Contact sections  64  are provided on the circuit board engagement sections  54 . The contact sections  64  extend from the terminal receiving cavities  24  into the board receiving slot  28 . 
   The wire stuffer cap  70 , as shown in  FIGS. 1 ,  3  and  7 , has a wire receiving face  72  through which wire receiving openings  74  extend. In the embodiment shown, four wire receiving openings  74  are provided to align with the four slots  56  (best shown in  FIG. 3 ). A latching slot  76  extends through the wire receiving face  72  at a location removed from wire receiving openings  74 . Referring to  FIG. 7 , a tool receiving slot  78  extends from a top surface  80  of the wire stuffer cap  70 . The tool receiving slot  78  is dimensioned to receive a blade of a screwdriver or other similar device therein. As shown in  FIGS. 1 ,  3  and  7 , a terminal receiving slot  82  extends from bottom surface  84  toward top surface  80 . The terminal receiving slot  82  is configured to receive and maintain the insulation displacement section  52  of the terminal  50  therein. A probe opening  86  extends from the top surface  80  to the terminal receiving slot  82 . This allows a probe to be inserted into the terminal receiving slot  82  to test the electrical connection between the terminal  50  and wires  94 . As shown in  FIGS. 3 and 7 , each wire stuffer cap  70  has a pivot seat  88  extending therefrom. In the embodiments shown, the pivot seats have a cylindrical configuration, but other configurations are possible. The pivot seat  88  has a slot  90  provided therein, the slot provides resiliency to either half of the pivot seat  88 . A detent  92  is provided on the surface of the pivot seat  88 . 
   Referring to  FIG. 1 and 2 , the wire stuffer cap  70  is initially provided in an open or up position. In this position, the lip  46  is positioned in detent  92 , thereby maintaining the wire stuffer cap  70  in the open position. As the detent  92  has engaged the lip  46 , the wire stuffer cap  70  will remain in its open position until it is purposefully pushed down into the closed position ( FIG. 7 ), thereby releasing the detent  92  from the lip  46 . In the open position, wires  94  are inserted into wire receiving openings  74 . The unstripped wires  94  are inserted into respective wire receiving openings  74  until the wires  94  engage stop projections. The stuffer cap  70  may be made of clear resin to allow for visual inspection of the inserted wires  94 . The stuffer cap  70  is depressed, causing the pivot seat  88  to pivot in the pivot cavity  44 , forcing the wires  94  down onto the insulation displacement sections  52  of the terminals  50 , causing the wires  94  to move into slots  56  which results in the insulation  96  of the wires  94  being pierced, placing the conductors  98  of the wires  94  in electrical and mechanical engagement with the insulation displacement sections  52  of the terminals  50 . The stuffer cap  70  can be moved by hand or by the work end of a screwdriver in cooperation with tool receiving slot  78  of stuffer cap  70 . The wire termination is similar to that disclosed in U.S. Pat. No. 5,667,402, which is hereby incorporated by reference. The wire size or wire gauge that is capable of being accommodated by the card edge connector  2  extends from 16 AWG to 28 AWG. 
   For different applications, different configurations may be needed. For example, non-uniform wire stuffer caps may be necessary for specific wiring applications. Obviously varied configurations of the card edge connector  2  may be fabricated to include two or more wire stuffer caps  70  being coupled in the housing  10 , and a varied number of wire receiving openings  74  being formed in each wire stuffer cap  70 . 
   Wire stuffer cap  70  is maintained in the closed position by the insertion of latching projections  23  in latching slot  76 . In this closed position, dividing wall  26  electrically and physically isolates the terminals  50  housed in the terminal receiving cavities  24 . A probe (not shown) may be inserted into the probe openings  86  to test if a proper electrical connection is provided between the conductors  98  of wires  94  and the insulation displacement sections  52  of terminals  50 . This allows each connection to be tested to determine if a problem exists, thereby preventing the needless movement of the wire stuffer cap  70  from the closed position. 
   As is shown in  FIGS. 1 ,  4  and  5 , two wires  94  are terminated to each terminal  50 . The dual slots  56  of each terminal  50  allow for the terminals  50  and card edge connectors  2  to be connected in series, daisy chained, or connect using other special wiring schemes. This can be useful, particularly in applications, such as shown in  FIG. 6 , in which the card edge connectors  2  are stacked or are engaged to form an expandable assembly made from card edge connectors  2 . As previously stated, the terminals may have a different number of slots depending on the application. In addition, different numbers of wires may be used depending upon the wiring scheme employed. 
   As best shown in  FIGS. 6 and 8 , a printed circuit card or board  110  can be inserted into the board receiving slot  28 . A lead-in surface  29  of the board receiving slot  28  guides the circuit board  110  into the board receiving slot  28 . As the circuit board  110  is inserted into the board receiving slot  28 , the circuit board  110  engages the contact sections  64  of the circuit board engagement sections  54  of the terminals  50 , causing the contact sections  64  and the circuit board engagement sections  54  to be resiliently displaced. Continuation of the insertion of the circuit board  110  continues until contact pads  112  positioned proximate the edge  114  of the circuit board  110  are placed in electrical and physical engagement with the contact sections  64  of the circuit board engagement sections  54 , as shown in  FIG. 8 . In this position, the contact sections  64  are biased against the contact pads  112  to provide the required electrical connection. In addition, as the circuit board  110  is inserted, the biasing of the contact sections  64  of the circuit board engagement sections  54  causes the contact sections  64  to wipe across the circuit pads  112 , thereby removing any contamination that may be present on the contact sections  64  or the circuit pads  112 . The circuit board  110  may be metal clad (not shown) on the side of the circuit board opposite the side on which the circuit pads  112  are positioned. The use of a metal clad circuit board is effective with this card edge connector  2 , as the contact sections  64  are positioned only on one side of the inserted circuit board  110 . The use of a metal clad circuit board can be beneficial because of the heat dissipation properties thereof. Essentially the metal cladding acts as a heat sink, drawing heat away from the LEDs. As the metal cladding has a large surface area, the heat is dissipated from the metal cladding in a more efficient manner than the heat is dissipated directly from the LED. 
   In the fully inserted position, the resiliency of the contact sections  64  ensures that the contact sections  64  will remain in engagement with the contact pads  112 , even if the circuit board  110  is slightly warped. Additionally, the circuit board  110  is maintained in the board receiving slot  28  by the biasing force exerted by the contact sections  64  on the circuit pads  112 . Alternatively, other known board latching devices may be incorporated without departing from the scope of the invention. As shown in  FIGS. 6 and 7 , the contact sections  64  and the circuit pads  112  may be staggered to allow for easier insertion and to distribute the biasing forces applied by the contact sections  64  to different points on the circuit board  110 , thereby preventing the circuit board  110  from pivoting relative to the card edge connector  2  when the circuit board  110  is fully mated to the card edge connector  2 . 
   In the embodiment shown in  FIG. 6 , the circuit board  110  has LEDs  116  provided thereon. It is often desirable to “stack” the LEDs  116  in series, as shown in  FIG. 6 . As previously described, the dual slotted terminals  50  allow the wires  94  to be connected in series, facilitating this type of arrangement. In addition, respective first mounting projections  32  and second mounting projections  38  allow the card edge connectors  2  to be physically joined in series to form a large connector assembly. Referring to  FIG. 9 , a respective first mounting projection  32  of a first card edge connector  2  is slid into a respective mounting recess  40  of a second card edge connector  2 . The card edge connectors  2  are offset along their longitudinal axis and are moved in the longitudinal direction such that the first mounting projection  32  is positioned in the mounting recess  40 . In this position, walls  34 ,  36  of first mounting projection  32  engage walls  42  of second mounting projections  38 . In so doing, the dovetail configuration prevents the card edge connectors  2  from being separated in a direction transverse to the longitudinal axis. 
   This type of card edge connector system allows for the tool free termination of the wires  94  and circuit boards  110 . The small size of the card edge connectors  2 , the stackability or modularity of the connectors and the use of the dual slotted terminals  50  allows the connectors to be arranged in multiple configurations according to the desired end use. 
   While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. For example, different requirements for varied applications and installations often dictate different terminal configurations. The card edge connector may be configured to meet these different requirements through use of different terminal configurations. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.