Abstract:
An electrical connector for connecting a cable to a card edge interface has a housing portion. The housing portion has a first surface, and a second surface opposite said first surface, and the surfaces are spaced apart to define a housing portion slot for the card edge interface. Furcated contact elements are disposed within the housing. Each contact element has a first tine portion with an exposed contact interface portion, a second tine portion; a web portion connecting the first and second tine portions, and a wire termination portion for terminating a conductor of the cable. The first and second tine portions are arranged within the housing portion with the contact interface exposed for mating with a respective contact surface of the card edge interface.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to a cable electrical connector, and more specifically to an electrical connector for connecting a multiple conductor power or signal cable to an edge of a printed circuit board (PC card) card. 
   BACKGROUND 
   Connector assemblies are required to provide electrical power or electrical or electronic control signals between components, such as computers, printers, auxiliary hardware, etc. Often these components contain panel members, such as PC cards, which are populated with miniaturized components to provide the desired electrical control. Usually, the connector assembly includes electrical contacts that extend from a housing that is secured adjacent to one end of the panel member. A mating connector assembly is configured for receiving the connector assembly. The operational reliability of the component is directly affected by the integrity of the connection. That is, if there is an insufficient electrical connection between the contacts, the components cannot operate as intended. In some applications, such as where the PC card contains high-powered light-emitting diodes (LEDs), the PC card and associated contacts are exposed to high temperatures, causing stress relaxation of the metal connector components. Stress relaxation of the connector components further exacerbates the problem by creating intermittent opening of the contacts, and reducing the normal force applied to the electrical contact points. 
   What is needed is a card edge cable connector that satisfies one or more of these needs or provides other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs. 
   SUMMARY 
   One embodiment relates to an electrical connector for connecting wire or cable to a card edge interface. The electrical connector has a housing portion. The housing portion has a first surface, and a second surface opposite said first surface. The first and second surfaces are spaced apart to define a slot. A plurality of furcated contact elements is disposed within the housing. Each contact element has a first tine portion including a contact interface portion, a second tine portion spaced apart from the first tine portion; a web portion connecting the first and second tine portions at one end, and a wire termination portion attached to the web portion for terminating a conductor of the cable. The first and second tine portions define an open recess corresponding with the housing portion slot, and are arranged within the housing portion with the contact interface exposed for mating with a respective contact surface of the card edge interface, the slot formed by the housing portion, and the contact elements receiving the card edge interface. 
   Another embodiment relates to an electrical connector for connecting a cable to a card edge interface. The electrical connector has a housing portion. The housing portion has a first surface, and a second surface opposite said first surface. The first and second surfaces are spaced apart to define a housing portion slot for receiving the card edge interface. A plurality of furcated contact elements is disposed within the housing. Each contact element has a first tine portion including a contact interface portion, a second tine portion spaced apart from the first tine portion; a web portion connecting the first and second tine portions at one end, and a wire termination portion attached to the web portion for terminating a conductor of the cable. The first and second tine portions define an open recess corresponding with the housing portion slot, and are arranged within the housing portion with the contact interface exposed for mating with a respective contact surface of the card edge interface. Each contact element is configured with a first slot having a projection defining a secondary slot; the secondary slot being filled with housing material flowed around the projection, wherein the contact element is secured within the housing portion. 
   Another embodiment relates to furcated contact element for an electrical connector. The connector includes a first tine portion with a contact interface portion; a second tine portion spaced apart from the first tine portion; a web portion connecting the first and second tine portions at one end, and a wire termination portion attached to the web portion for terminating a conductor of a cable. The first and second tine portions define an open recess corresponding with a slot of a housing portion. The tine portions are arranged within the housing portion with the contact interface exposed for mating with a respective contact surface of a card edge interface, the slot formed by the housing portion, and contact elements receiving the card edge interface. The wire termination portion has a cup portion for receiving molten solder. The cup portion defines an aperture that is substantially coaxial with the plane of the contact element. An axis of the conductor is maintained approximately at the centerline of the contact element when the conductor is soldered to the contact element. 
   Yet another embodiment is directed to a solder cup to provide a solder connection to a wire termination. The solder cup includes a cup portion having a first beam portion and a second beam portion. The first beam portion is disposed on one side of a centerline of the cup portion and the second beam portion is disposed opposite the first beam portion. The first and second beam portions define an aperture for inserting a wire conductor prior to receiving the molten solder. The cup portion is configured to receive molten solder and retain a portion of the solder in solid form. An axis of the conductor is maintained approximately at the centerline of the contact element when the conductor is soldered to the contact element. 
   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 
     The application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which: 
       FIG. 1  is a perspective view of the card edge cable connector and PC card. 
       FIG. 2  is a cross-sectional view of the connector taken along the lines  2 - 2  in  FIG. 1 . 
       FIG. 3  is an end view of the contact portion of the connector. 
       FIG. 4  is a partial sectional view showing the PC card detent latch. 
       FIG. 5  is a perspective view of the connector. 
       FIG. 6  is a view of a single contact element. 
       FIG. 7  is an end view of the contact portion taken along the lines  7 - 7  in  FIG. 6 . 
       FIG. 8  is a cross-sectional view through the connector. 
       FIG. 9  is a perspective view of the connector and a PCB. 
       FIG. 10  is a cross-sectional view of the connector housing engaging the PCB. 
       FIG. 11  is a partial perspective view of a wire being inserted into the contact termination. 
       FIG. 12  is a partial perspective view of a wire soldered within the contact termination. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring first to  FIGS. 1 and 2 , a card (or edge cable connector  10  and PC card  12  are shown. Electrical contact elements  14  are inserted within a housing portion  16 . The housing portion  16  is an electrically insulating material. A high-temperature resin may be employed for applications that expose the connector  10  to high temperatures, e.g., if the components of the PC card  12  include high-temperature LEDs, or if the card or PC card substrate has an aluminum core for heat dissipation. 
   Furcated contact elements  14  include an upper tine  18  and a lower tine portion  20 . The upper tine portion  18  and lower tine portion  20  are joined at one end by a web portion  22 . The novel furcated design provides a high normal contact force for reliable and stable connection to the plated contacts  24  of the PC card  12 , while maintaining a tight contact-to-contact centerline or pitch. The web portion  22  provides a reinforced joint at the intersection of the upper and lower tine portions  18 ,  20 , which is resistant to metal deformation due to heat- and mechanically-induced stresses, as described in greater detail below. A plated interface  26  aligns with the plated PC card contacts  24 . The contact base material may be a high-temperature copper alloy, e.g., phosphor bronze, beryllium copper, or similar copper alloys with resistance to stress relaxation, as will be known to those skilled in the art. A wire termination portion  28  is disposed on the contact element  14  at the end opposite of the tines  18 ,  20 . Wires  30  have insulated jackets, a portion of which is stripped from the end for electrically joining the wire  30  to the wire termination portion  28 . The wires  30  may be soldered, welded or crimped into the wire termination portion  28 . 
   The housing is designed to insulate the furcated contact lower tine  20  from the bottom and edge of the circuit board  12 . An insulating layer  36  of the housing  16  provides the electrical isolation of the lower tine  20  from the PC card  12 . In one embodiment, the PC card  12  has an aluminum core for improved heat dissipation characteristics and rigidity. Alternatively, the PC card  12  may comprise a conventional epoxy resin substrate. 
     FIG. 3  is a mating end view of the contact portion of the connector  10 . The forward end  50  has a slot  52  having a width approximately equal to, or slightly greater, than the thickness of the PC card  12  substrate, so that the connector  10  engages with the PC card  12  in an interference fit with the contact interface  26 . Opposing surfaces  54 ,  56  adjacent either side of the slot  52  are tapered from a wider dimension at front surface  50  to a narrower dimension at the rear of the slot  52 , to promote engagement of the connector  10  and PC card  12 , and prevent interference when joining them together. Also shown are the contact interfaces  26 , which project downward into the slot  52  from the top portion  60 , to engage the plated contact pads  24  (See, e.g.,  FIG. 2 ). Detent latch  32  is disposed adjacent the forward edge  50  of the connector. 
   Referring next to  FIGS. 4 and 5 , in one embodiment of the connector  10  the detent latch  32  engages an aperture  34  positioned in the PC card  12 . The aperture  34  and detent latch  32  provide retention between the housing portion  16  and the PC card  12 . The detent latch  32  provides additional retention force of the connector  10  to the PC card  12  that supplements the friction retention imparted by the normal force of the contact elements  14  in engagement with the PC card contact pads  24 . The contacts may be arranged at a predetermined pitch with respect to the PC card  12  for facilitating alignment with the PC card  12 . 
     FIG. 6  is an isolated view of a contact element  14  apart from the connector housing  16 . The contact element  14  may be configured with a slot  38  having a projection  40  defining a secondary slot  42 . The contact element  14  is retained within the housing by detent  70 . Web portion  22  connects tines  18 ,  20 , with sufficient cross-sectional area to inhibit angular flexing and stress relaxation of the tines  18 ,  20 . The contact guide channel  66  (See, e.g.,  FIG. 8 ) also restricts angular flexing of tines  18 ,  20  within the width of the guide channel  66 . The tines  18 ,  20 , contact interface  26 , projection  40 , wire termination portion  28 , slot  38 , secondary slot  42 , and other features of the contact element  14  may be stamped from a flat metallic strip of copper or copper-alloy, as described above. 
   Referring to  FIG. 7 , an end view of the contact portion  14  shows alternating beam portions  44 , 46  formed in the wire termination portion to provide an aperture or solder cup  48  for inserting stripped wire ends  78  into the wire termination portion  28 , where the wire ends are soldered to the wire termination portion  28  by a soldering material (designated by hashing  84 ). In one embodiment, the alternating beams  44 ,  46  are formed outwardly on opposing sides of the centerline of the contact portion  14  to allow for the wire to be aligned with the centerline of the contact portion  14  when inserted. 
   Referring next to  FIG. 8 , a cross-sectional view through the connector  10  shows the contact detent  70  engaging the shelf portion  62  of the housing portion  16 . The alternating beam portions  44 ,  46  of the contact portion  14  are separated from the detent portion  70  by the shelf portion  62 . The shelf portion  62  latches the contact portion  14  into the housing portion  16  when the contact portion  14  is fully inserted into the guide channel  66 . The projection  40  abuts the end of guide channel  66  opposite the shelf portion  62 , to limit the penetration of the contact portion  14  in the housing portion  16 . 
   Referring next to  FIGS. 9 and 10 , in one embodiment alignment slots  72 ,  74  may be disposed on the PCB or mating cable connector  12 , to align. When the connector  10  is coupled together with the PCB  12 , indicated by arrow  76 , housing wall  64  engages with alignment slot  72  to align them relative to each other, and to ensure proper polarity. A second alignment  72  slot may be provided at the opposite end of the connector  10 , for engaging a housing wall  64 . Alignment may be further ensured by aperture  34  if a detent portion  32  is used to prevent the housing portion  16  from receding from the PCB  12 . 
   Referring next to  FIGS. 11 and 12 , in one embodiment there is a novel configuration for the solder cup  48  that provides a soldered connection (designated by the cross-hatching  84 ) that allows the soldered connections to have a narrow profile, and thus enabling a smaller connector  10 , or an increased number of wires across the width of the connector  10 . The wire  30  includes an insulation jacket  80  surrounding a conductor core  78 . The jacket  80  is stripped away from the core  78  at an end portion  88 , and the core  78  is inserted, as indicated by arrow  82 , into the solder cups  48  that are defined between opposing beam portions  44  and  46 . The wire is maintained approximately at the axis or centerline of the contact portion  14  by the beam portions  44  and  46  and solder cups  48 . The core  78  may be inserted into the solder cup  48  and soldered by conventional soldering means. Alternately the core  48  may be pre-coated with a tin or tin alloy layer designed to re-flow when heated to bond the wire core  78  to the contact portion  14 . 
   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. 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.