Patent Publication Number: US-10320102-B2

Title: Receptacle connector with contact assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of, and claims benefit to the filing date of, U.S. patent application Ser. No. 15/230,882, filed Aug. 8, 2016, entitled “RECEPTACLE CONNECTOR WITH CONTACT ASSEMBLY”, the subject matter of which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter herein relates generally to receptacle connectors having contact assemblies. 
     High speed electrical connectors typically transmit and receive data signals across a mating interface. For example, some known receptacle connectors are mounted to a circuit board and include a card slot that receives a card edge of a plug connector at the mating interface. The receptacle connectors have contacts including deflectable spring beams at the mating interface that are spring loaded against the plug connector when the plug connector is loaded into the slot. The contacts are typically loaded or stitched into the housing. However, receptacle connectors having contacts on tight centerline spacing have problems with manufacturing the housing because the walls between channels holding the contacts are relatively thin, and there are problems holding the contacts in the channels because the thin walls have insufficient material to retain the contacts. Some known receptacle connectors utilize contact assemblies that are loaded into the housing. However, such receptacle connectors have problems retaining the contact assemblies in the housing. For example, press-fit features used to hold the contact assembly become stressed under the mating load. Additionally, the housing tends to bow and open up, causing insufficient retaining forces to hold the contact assembly in the housing. Additionally, the bowing changes the shape of the housing causing the positioning of the housing and the contact beams to be misaligned from each other, from the plug connector and/or from the circuit board. 
     A need remains for a receptacle connector that retains and positions a contact assembly for mating with a plug connector and mounting to a circuit board. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In an embodiment, a receptacle connector configured to mate with a plug connector is provided including a contact assembly having a first contact sub-assembly and a second contact sub-assembly coupled to the first contact sub-assembly. The first and second contact sub-assemblies have corresponding first and second dielectric carriers. The first and second contact sub-assemblies have contacts held by the first and second dielectric carriers, respectively. The contacts are arranged in first and second contacts arrays aligned in corresponding first and second rows. The contacts have mating ends configured for electrical connection with the plug connector, terminating ends configured for electrical connection with a circuit board, and intermediate sections between the mating ends and the terminating ends being overmolded by an overmolded body forming the corresponding first and second dielectric carriers. The receptacle connector includes a housing holding the contact assembly having a mating end at a top of the housing configured to mate with the plug connector and a mounting end at a bottom of the housing configured to be mounted to the circuit board. The housing has first and second side walls extending between the top and the bottom. The housing has first and second end walls extending between the top and the bottom. The housing has a card slot open at the top for receiving the plug connector with the mating ends of the contacts being exposed in the card slot for mating electrical connection with the plug connector. The housing has a contact assembly cavity open at the bottom for receiving the contact assembly. 
     In another embodiment, a receptacle connector configured to mate with a plug connector is provided including a contact assembly having a dielectric carrier holding contacts having mating ends configured for electrical connection with the plug connector, terminating ends configured for electrical connection with a circuit board, and intermediate sections between the mating ends and the terminating ends passing through the dielectric carrier. The receptacle connector includes a housing holding the contact assembly having a mating end at a top of the housing configured to mate with the plug connector and a mounting end at a bottom of the housing configured to be mounted to the circuit board. The housing has first and second side walls extending between the top and the bottom and first and second end walls extending between the top and the bottom. The housing has a card slot open at the top for receiving the plug connector with the mating ends of the contacts being exposed in the card slot for mating electrical connection with the plug connector. The housing has a contact assembly cavity open at the bottom for receiving the contact assembly. The housing has positioning ribs extending from the first and second side walls into the contact assembly cavity to position the contact assembly within the contact assembly cavity. 
     In a further embodiment, a receptacle connector configured to mate with a plug connector is provided including a contact assembly having a dielectric carrier holding contacts having mating ends configured for electrical connection with the plug connector, terminating ends configured for electrical connection with a circuit board, and intermediate sections between the mating ends and the terminating ends passing through the dielectric carrier. The receptacle connector includes a housing holding the contact assembly having a mating end at a top of the housing configured to mate with the plug connector and a mounting end at a bottom of the housing configured to be mounted to the circuit board. The housing has first and second side walls extending between the top and the bottom and first and second end walls extending between the top and the bottom. The housing has a card slot open at the top for receiving the plug connector with the mating ends of the contacts being exposed in the card slot for mating electrical connection with the plug connector. The housing has a contact assembly cavity open at the bottom for receiving the contact assembly. The housing has strengthening ribs extending across the contact assembly cavity to connect the first side wall to the second side walls at a location remote from the first end wall and remote from the second end wall. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top perspective view of an electrical connector system according to an exemplary embodiment showing a plug connector mated with a receptacle connector. 
         FIG. 2  is a top perspective view of the electrical connector system showing the plug connector poised for mating with the receptacle connector. 
         FIG. 3  is a perspective view of a contact assembly for the receptacle connector according to an exemplary embodiment. 
         FIG. 4  is a perspective view of the contact assembly in an unassembled state. 
         FIG. 5  is a perspective view of a portion of the contact assembly. 
         FIG. 6  is a top perspective view of the receptacle connector in accordance with an exemplary embodiment. 
         FIGS. 7 and 8  are bottom perspective views of a housing of the receptacle connector in accordance with an exemplary embodiment. 
         FIG. 9  is a bottom view of a portion of the housing in accordance with an exemplary embodiment. 
         FIG. 10  is a bottom view of the receptacle connector showing the contact assembly loaded in a contact assembly cavity at a bottom of the housing. 
         FIG. 11  is a partial sectional view of the receptacle connector in accordance with an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a top perspective view of an electrical connector system  100  according to an exemplary embodiment showing components in a mated state.  FIG. 2  is a top perspective view of the electrical connector system  100  showing components in an unmated state. The electrical connector system  100  includes a circuit board  102  and a receptacle connector  104  mounted to the circuit board  102  configured to electrically connect to a plug connector  105  in order to provide an electrically conductive signal path between the circuit board  102  and the plug connector  105 . The receptacle connector  104  may be a high speed connector that transmits data signals at speeds over 10 gigabits per second (Gbps), such as over 25 Gbps. The receptacle connector  104  may also be configured to transmit low speed data signals and/or power. The receptacle connector optionally may be an input-output (I/O) connector. 
     The receptacle connector  104  includes a housing  106  extending between a mating end  108  and a mounting end  110 . The mounting end  110  is terminated to a top surface of the circuit board  102 . The mating end  108  defines an interface for connecting to the plug connector  105 . In the illustrated embodiment, the mating end  108  defines a socket or card slot  112  that is configured to receive the plug connector  105  therein. For example, a mating end of the plug connector  105  may be defined by a card edge  114  ( FIG. 2 ) thereof. The card edge  114  may be an edge of a circuit card of the plug connector  105  having exposed conductors on one or both sides thereof configured to be plugged into the card slot  112 . In other various embodiments, the card edge  114  may be an edge of a plug housing having exposed conductors on one or both sides thereof configured to be plugged into the card slot  112  or the card edge  114  may be another pluggable structure configured to be received in the card slot  112  for electrical connection with the receptacle connector  104 . 
     The receptacle connector  104 , in the illustrated embodiment, is a vertical board-mount connector such that the card slot  112  is configured to receive the plug connector  105  in a loading direction that is transverse to, such as perpendicular to, the top surface of the circuit board  102 . In an alternative environment, the receptacle connector  104  may be a right angle style connector that is configured to receive the plug connector  105  in a loading direction that is parallel to the top surface. In another alternative embodiment, the receptacle connector  104  may be terminated to an electrical cable instead of to the circuit board  102 . Optionally, the plug connector  105  may be a transceiver style connector that is configured to be terminated to one or more cables. 
     The housing  106  of the receptacle connector  104  holds a plurality of contacts  116  held at least partially within the housing  106 . The housing  106  extends between a top  118  and an opposite bottom  120 . The top  118  defines the mating end  108  of the connector  104  such that the card slot  112  extends into the connector  104  via the top  118 . The bottom  120  may define at least a portion of the mounting end  110  of the connector  104 . For example, the bottom  120  abuts or at least faces the top surface of the circuit board  102 . The card slot  112  is defined by a first side wall  122 , a second side wall  124 , and first and second end walls  126 ,  128  that each extend between the side walls  122 ,  124 . The side walls  122 ,  124  and end walls  126 ,  128  extend from the top  118  of the housing  106  towards the bottom  120 . As used herein, relative or spatial terms such as “front,” “rear,” “first,” “second,”, “top”, “bottom”, “left,” and “right” are only used to distinguish the referenced elements and do not necessarily require particular positions or orientations in the connector system  100  or the receptacle connector  104  relative to gravity or relative to the surrounding environment. 
     The contacts  116  of the receptacle connector  104  are configured to provide conductive signal paths through the receptacle connector  104 . For example, each contact  116  includes a contact beam or spring beam defining a mating end  130  of the contact  116  configured to engage and electrically connect to a corresponding conductor (for example, trace or mating contact) of the plug connector  105  within the card slot  112  when the plug connector  105  is fully mated to the receptacle connector  104 . The mating end  130  engages the mating conductor at a separable mating interface. The mating ends  130  are disposed within the card slot  112 . The contacts  116  further include terminating ends  132  configured to be terminated to corresponding contact elements (not shown) of the circuit board  102  via thru-hole mounting to conductive vias, surface-mounting to conductive pads, and/or the like. In the illustrated embodiment, the terminating ends  132  of the contacts  116  are surface-mounted to pads on the top surface of the circuit board  102  and may be soldered to the pads on the circuit board  102 . 
     In an embodiment, the contacts  116  are organized in at least one contact array  134 . The contacts  116  in a respective array  134  are arranged side-by-side in a row. In the illustrated embodiment, the contacts  116  are organized in two arrays  134 . The only portions of the contacts  116  in a first contact array  134 A of the two arrays  134  that are visible in  FIG. 2  are the mating ends  130 , while the only portions of the contacts  116  in a second contact array  134 B of the two arrays  134  that are visible are the terminating ends  132 . The mating ends  130  of the contacts  116  in the first array  134 A extend at least partially into the card slot  112  from the first side wall  122 , and the mating ends  130  of the contacts  116  of the second array  134 B extend at least partially into the card slot  112  from the second side wall  124 . Thus, the mating ends  130  of the first array  134 A of contacts  116  are configured to engage one side of the card edge  114  of the plug connector  105 , while the mating ends  130  of the second array  134 B of contacts  116  are configured to engage the opposite side of the card edge  114 . The mating ends  130  may be configured to deflect towards and/or into the respective side walls  122 ,  124  from which the mating ends  130  extend in order to exert a biased retention force on the plug connector  105  to retain mechanical and electrical contact with the corresponding mating conductors. The card edge  114  of the plug connector  105  may be generally centered within the card slot  112  to balance the mating forces of the contacts  116 . In an exemplary embodiment, the housing  106  includes alignment features to ensure that the plug connector  105  is generally centered within the card slot  112 , which may reduce over-travel, and thus damage, to the contacts  116 . 
       FIG. 3  is a perspective view of a contact assembly  136  for the receptacle connector  104  (shown in  FIG. 1 ) according to an exemplary embodiment.  FIG. 4  is a perspective view of the contact assembly  136  in an unassembled state.  FIG. 5  is a perspective view of a portion of the contact assembly  136 . In the illustrated embodiment, the contact assembly  136  includes first and second contact sub-assemblies  138 A,  138 B ( FIG. 5  illustrates the first contact sub-assembly  138 A), configured to be coupled together to form the contact assembly  136 . Each contact sub-assembly  138  includes a dielectric carrier  140  (which may be identified as first and second dielectric carriers  140 A and  140 B, respectively) holding a plurality of the contacts  116 . Optionally, as in the illustrated embodiment, the contact sub-assemblies  138 A,  138 B may be identical components inverted 180° and coupled together. In other embodiments, the contact sub-assemblies  138 A,  138 B may be similar to each other, but not identical, having some different features, such as securing features for securing the components together and/or to the housing  106  (shown in  FIG. 1 ). Optionally, the contact sub-assemblies  138 A,  138 B may be hermaphroditic having hermaphroditic securing features (for example, posts and openings). 
     The contacts  116  are distributed in the arrays  134 A,  134 B. For example, the first array  134 A is provided in the first contact sub-assembly  138 A and the second array  134 B is provided in the second contact sub-assembly  138 B. The mating ends  130  of the contacts  116  in the first array  134 A are arranged side-by-side in a first row  144  ( FIG. 3 ), and the mating ends  130  of the contacts  116  in the second array  134 B are arranged side-by-side in a second row  146  ( FIG. 3 ). The first and second rows  144 ,  146  extend parallel to each other on opposite sides of a central plane  148  of the contact assembly  136  (the central plane  148  is shown oriented vertically and extending longitudinally through the contact assembly  136 ). 
     Each contact  116  extends continuously between the terminating end  132  and the mating end  130 . Adjacent contacts  116  in the same array  134  may extend parallel to one another. The contacts  116  are composed of an electrically conductive material, such as one or more metals. The contacts  116  may be stamped and formed into shape from a flat sheet of metal. In an embodiment, at least some of the contacts  116  of the receptacle connector  104  are used to convey high speed data signals and some other contacts  116  are used as ground conductors to provide electrical shielding for the high speed signals and ground paths through the receptacle connector  104 . Some of the contacts  116  may be used to provide low speed data signals, power, or the like, instead of high speed data signals. 
     The contacts  116  in each array  134  are evenly spaced-apart along the longitudinal axis of the contact assembly  136 . In an embodiment, the contacts  116  are held in place by the dielectric carrier  140 . The dielectric carrier  140  extends between a top  152  and a bottom  154 . The dielectric carrier  140  has a front  156  and a rear  158  between the top  152  and the bottom  154 . The rears  158  of the dielectric carriers  140  face and may abut against each other when the contact assembly  136  is assembled. 
     The rear  158  of each dielectric carrier  140  may include one or more securing features  160  for securing the dielectric carriers  140  together when the contact assembly  136  is assembled. The securing features  160  may interact with each other to secure the contact sub-assemblies  138  together. For example, the securing features  160  may be any combination of posts, openings, latches, catches, clips, fasteners or other types of securing features. In the illustrated embodiment, the securing features include posts  160 A and openings  160 B configured to receive the posts  160 A of the other dielectric carrier  140 . The posts  160 A may be held in corresponding openings  160 B by an interference or friction fit to secure the dielectric carriers  140  together. In the illustrated embodiment, the dielectric carriers  140  include two posts  160 A at one end and two openings  160 B at the other end thereof; however, any number and/or layout of posts  160 A and openings  160 B may be used in alternative embodiments. The openings  160 B may be hexagonal shaped in some embodiments. In other alternative embodiments, rather than having two dielectric carriers  140 , the contact assembly  136  may include a single dielectric carrier  140  holding either a single array  134  or multiple arrays  134 . 
     The fronts  156  of the dielectric carriers  140  may face in opposite directions and may engage the housing  106 . The front  156  of either or both dielectric carriers  140  may include one or more securing features  162  for securing the contact assembly  136  to the housing  106 . The securing features  162  may interact with corresponding securing features of the housing  106  to secure the contact assembly  136  to the housing  106 . For example, the securing features  162  may be any combination of clips, latches, catches, protrusions, openings or other types of securing features. In the illustrated embodiment, the securing features  162  are ramp-shaped catches used to interact with corresponding latches on the housing  106 . 
     The contacts  116  extend through the dielectric carrier  140  such that the mating ends  130  protrude from the top  152  and terminating ends  132  protrude from the bottom  154  with the dielectric carrier  140  engaging and holding an intermediate section  164  of the contacts  116  to retain the relative positioning and orientations of the contacts  116 . 
     The dielectric carrier  140  is formed of a dielectric material, such as a plastic or one or more other polymers. Optionally, the dielectric carrier  140  may be overmolded around the contacts  116 . For example, the dielectric carrier  140  may include an overmolded body  166  molded around the intermediate sections  164  of the contacts  116 . The overmolded body  166  is formed in place around the contacts  116 . The overmolded body  166  may be injection molded around the contacts  116 , which may be held together as part of a leadframe prior to overmolding. Alternatively, the contacts  116  may be loaded or stitched into a pre-formed dielectric carrier  140 . 
     In an exemplary embodiment, the dielectric carrier  140  includes channels  168  formed in the top  152 . The channels  168  are formed between various contacts  116 . The channels  168  are configured to receive a portion of the housing  106  when the contact assembly  136  is loaded into the housing  106 . The overmolded body  166  may be secured to the portion of the housing  106  received in the channels  168  by an interference fit. For example, the overmolded body  166  may include crush ribs or other securing features in the channel  168  to secure the dielectric carrier  140  to the housing  106 . 
       FIG. 6  is a top perspective view of the receptacle connector  104  in accordance with an exemplary embodiment. When assembled, the contact assembly  136  is received in the housing  106  such that the mating ends  130  of the contacts  116  are exposed within the card slot  112 . In an exemplary embodiment, the housing  106  includes a plurality of contact channels  180  in the first and second side walls  122 ,  124 . Each contact channel  180  receives a corresponding contact  116 . The housing  106  includes separating walls  182  between the contact channels  180 . The separating walls  182  hold the relative positions of the contacts  116 . The separating walls  182  hold the contacts  116  in the contact channels  180 . The separating walls  182  hold the contacts  116  parallel to each other and/or parallel to the mating direction with the plug connector  105  (shown in  FIG. 1 ). 
     In an exemplary embodiment, the mating ends  130  are deflectable into the contact channels  180  when the plug connector  105  ( FIG. 1 ) is loaded into the card slot  112 . When the mating ends  130  are deflected, the contacts  116  are spring loaded against the plug connector  105  due to an internal biasing force exerted by the spring beams of the contacts  116 . Spring loading the contacts  116  creates a mechanical and electrical connection with the plug connector  105 . In an exemplary embodiment, the housing  106  may include features that center the plug connector  105  within the card slot  112  to prevent over-travel of any of the contacts  116  caused when the mating ends  130  are deflected beyond an elastic limit. Centering the plug connector  105  also balances the opposing spring forces of the two rows of contacts  116 . 
       FIGS. 7 and 8  are bottom perspective views of the housing  106  of the receptacle connector  104  in accordance with an exemplary embodiment. The housing  106  includes a contact assembly cavity  170  at the bottom  120  that receives the contact assembly  136  (shown in  FIG. 3 ). The contact assembly cavity  170  is positioned below the card slot  112 . Optionally, the contact assembly cavity  170  may be wider than the card slot  112 . The contact channels  180  and the separating walls  182  are shown in  FIGS. 7 and 8 . 
     The housing  106  includes end wall positioning ribs  172  on the end walls  126 ,  128 . The end wall positioning ribs  172  longitudinally position and/or center the contact assembly  136  ( FIGS. 3 and 6 ) within the contact assembly cavity  170 . Optionally, the end wall positioning ribs  172  may be crush ribs configured to deform or crush when the contact assembly  136  is loaded into the contact assembly cavity  170 . The contact assembly  136  may be held in the contact assembly cavity  170  by an interference fit between the end wall positioning ribs  172 . For example, the end wall positioning ribs  172  may engage the dielectric carriers  140  with a holding force sufficient to retain the contact assembly  136  in the contact assembly cavity  170 . 
     The housing  106  includes side wall positioning ribs  174  on the side walls  122 ,  124 . The side wall positioning ribs  174  laterally position and/or center the contact assembly  136  within the contact assembly cavity  170 . Optionally, the side wall positioning ribs  174  may be crush ribs configured to deform or crush when the contact assembly  136  is loaded into the contact assembly cavity  170 . The contact assembly  136  may be held in the contact assembly cavity  170  by an interference fit between the side wall positioning ribs  174 . For example, the side wall positioning ribs  174  may engage the dielectric carriers  140  with a holding force (for example, a force sufficient to retain the contact assembly  136  in the contact assembly cavity  170 ). Alternatively, rather than securing the contact assembly  136  in the contact assembly cavity  170 , the side wall positioning ribs  174  may serve merely for alignment of the contact assembly  136  within the contact assembly cavity  170  rather than holding or securing the contact assembly  136  in the contact assembly cavity  170 . For example, while the side wall positioning ribs  174  may engage one or both sides of the contact assembly  136 , the side wall positioning ribs  174  may engage the contact assembly  136  with a non-holding force (for example, a force insufficient to retain the contact assembly  136  in the contact assembly cavity  170 ). 
     In an exemplary embodiment, the housing  106  includes different types of side wall positioning ribs  174 . For example, the housing  106  includes primary positioning ribs  176  and secondary positioning ribs  178 . The primary positioning ribs  176  are press-fit against the contact assembly  136  to hold the contact assembly  136  in the contact assembly cavity  170 , and as such define press-fit ribs  176 . The press-fit ribs  176  may be crush ribs configured to deform or crush when the contact assembly  136  is loaded into the contact assembly cavity  170 . The press-fit ribs  176  impart a holding force on the contact assembly  136  sufficient to retain the contact assembly  136  in the contact assembly cavity  170  (either alone or cumulatively as a set with other press-fit ribs  176  and/or the end wall positioning ribs  172 ). The secondary positioning ribs  178  are used for aligning the contact assembly  136  in the contact assembly cavity  170  without being press-fit against the contact assembly  136 , and may be referred to hereinafter as alignment-fit ribs  178 . The alignment-fit ribs  178  have less holding force than the press-fit ribs  176 . The secondary positioning ribs  178  may engage the contact assembly  136 , such as to control the alignment or position of the contact assembly  136  (for example, to hold the contact assembly  136  a spaced distance from the corresponding side wall  122 ,  124 ); however, each of the secondary positioning ribs  178  do not necessarily need to engage the contact assembly  136  as the contact assembly  136 , the housing  106  and/or the secondary positioning ribs  178  may be designed with a tolerance so the components do not bind when assembled. 
     In an exemplary embodiment, the press-fit ribs  176  are provided closer to the end walls  126 ,  128  while the alignment-fit ribs  178  are provided closer to the longitudinal center of the housing  106 . For example, in the illustrated embodiment, three press-fit ribs  176  are provided at each end portion (for example, the outer thirds) of each side wall  122 ,  124  near the corresponding end walls  126 ,  128  while two alignment-fit ribs  178  are provided at the center portions (for example, the central third) of each side wall  122 ,  124 . Because the side walls  122 ,  124  are more rigidly held relative to each other near the end walls  126 ,  128  due to the support provided by the end walls  126 ,  128 , the end portions of the side walls  122 ,  124  are more apt to hold the contact assembly  136 . Thus, the primary or press-fit ribs  176  are located along the end portions of the side walls  122 ,  124  near the end walls  126 ,  128 . In contrast, because the side walls  122 ,  124  are unsupported, and thus more flimsy near the center portion of the side walls  122 ,  124 , the secondary or alignment-fit ribs  178  are provided at the center portions of the side walls  122 ,  124 . Additionally, if press-fit ribs  176  were provided at the center portions of the side walls  122 ,  124 , the center portions may tend to bow or flex outward, which may cause improper positioning of the contact assembly  136  within the housing  106  and/or improper positioning of the housing  106  on the circuit board  102 , which may lead to misalignment of the contacts  116  with the pads on the circuit board  102 . However, in alternative embodiments, the side walls  122 ,  124  may be made more robust, such as thicker, to withstand the holding forces of press-fit ribs  176  in the center portions of the side walls  122 ,  124 , and/or strengthening ribs may be provided across the contact assembly cavity  170  to provide additional support, as described in further detail below. 
     The housing  106  includes securing features  184  that interact with the securing features  162  (shown in  FIG. 3 ) of the contact assembly  136  to hold the contact assembly  136  in the contact assembly cavity  170 . In the illustrated embodiment, the securing features  184  are latches used to engage the catches defining the securing features  162 ; however, other types of securing features  184  may be provided in alternative embodiments. The securing features  184  are provided on both side walls  122 ,  124 ; however, only one of the side walls  122 ,  124  may have securing features  184  in alternative embodiments. In other alternative embodiments, the end walls  126 ,  128  may include the securing features  184 . 
     In an exemplary embodiment, the housing  106  includes strengthening ribs  190  extending across the contact assembly cavity  170  to connect the first side wall  122  to the second side wall  124  at locations remote from the first end wall  126  and remote from the second end wall  128 . The strengthening ribs  190  may be provided at or near the center portions of the side walls  122 ,  124 . The strengthening ribs  190  tie the first and second side walls  122 ,  124  together to resist bowing outward of the first and second side walls  122 ,  124 . The strengthening ribs  190  brace the side walls  122 ,  124  at multiple locations to resist warping, bowing or flexing of the side walls  122 ,  124 , which may keep the side walls  122 ,  124  straighter in the longitudinal direction, particularly for longer housings  106 . Providing the strengthening ribs  190  may allow the housing  106  to be manufactured with a less expensive material while still achieving the same amount of rigidity. 
       FIG. 9  is a bottom view of a portion of the housing  106  in accordance with an exemplary embodiment. The end wall positioning ribs  172  and the side wall positioning ribs  174  are shown in  FIG. 9 , including both press-fit ribs  176  and alignment-fit ribs  178 . The positioning ribs  176 ,  178  extend from both the first and second side walls  122 ,  124  into the contact assembly cavity  170  to position the contact assembly  136  ( FIG. 3 ) within the contact assembly cavity  170 . As noted above, both types of positioning ribs  176 ,  178  are used to position the contact assembly  136  in the contact assembly cavity  170 ; however, the press-fit positioning ribs  176  more tightly engage the contact assembly  136  than the alignment-fit positioning ribs  178 . For example, the press-fit positioning ribs  176  are used for both aligning and securing the contact assembly  136  while the alignment-fit positioning ribs  178  are used for alignment of the contact assembly  136 , such as centering the contact assembly  136 , without securing the contact assembly  136  in the cavity  170 . In the illustrated embodiment, the primary or press-fit ribs  176  are located closer to the end wall  126  outside of the secondary or alignment-fit ribs  178 . For example, the press-fit ribs  176  are positioned between the alignment-fit ribs  178  and the end wall  126 . In other various embodiments, the side wall positioning ribs  174  may only include the press-fit positioning ribs  176  or may only include the alignment-fit positioning ribs  178 . 
     In an exemplary embodiment, the primary or press-fit ribs  176  extend from the housing  106  into the contact assembly cavity  170  a first depth  200  while the secondary or alignment-fit ribs  178  extend from the housing  106  into the contact assembly cavity  170  a second depth  202  less than the first depth  200 . The alignment-fit ribs  178  on the first side wall  122  define a first alignment plane  204  and the alignment-fit ribs  178  on the second side wall  124  define a second alignment plane  206 . The alignment planes  204 ,  206  are spaced-apart from interior surfaces  208 ,  210  of the side walls  122 ,  124  to define gaps  212 ,  214 , respectively. The alignment-fit ribs  178  block the contact assembly  136  from entering the gaps  212 ,  214  ensuring that the contact assembly  136  does not drift too close to the first side wall  122  or the second side wall  124 , which could overstress the contacts  116  by bending the contacts  116  beyond over-travel limits or elastically deforming the contacts  116 . The press-fit ribs  176  on the first side wall  122  extend into the contact assembly cavity  170  beyond the first alignment plane  204 . The press-fit ribs  176  on the second side wall  124  extend into the contact assembly cavity  170  beyond the second alignment plane  206 . 
     In an exemplary embodiment, the contact assembly cavity  170  has a first width  220  defined between the side walls  122 ,  124 . A second width  222  is defined between the alignment planes  204 ,  206  and is narrower than the first width  220 . Optionally, the alignment-fit ribs  178  may be aligned with each other on opposite sides of the contact assembly cavity  170  and thus the second width  222  is the width between the outer edges of the alignment-fit ribs  178 . However, in other embodiments, the alignment-fit ribs  178  may be staggered or off-set from each other across the contact assembly cavity  170 . A third width  224  is defined between the press-fit ribs  176  and is narrower than the second width  222 . Optionally, the press-fit ribs  176  may be aligned with each other on opposite sides of the contact assembly cavity  170  and thus the third width  224  is the width between the outer edges of the press-fit ribs  176 . However, in other embodiments, the press-fit ribs  176  may be staggered or off-set from each other across the contact assembly cavity  170 , in which case the third width  224  is the width between planes defined by the outer edges of the press-fit ribs  176 . 
       FIG. 10  is a bottom view of the receptacle connector  104  showing the contact assembly  136  loaded in the contact assembly cavity  170  at the bottom  120  of the housing  106 . The contact assembly  136  is loaded into the contact assembly cavity  170  until the terminating ends  132  of the contacts  116  are at the bottom  120 . The terminating ends  132  of the first and second contact arrays  134 A,  134 B extend away from each other in opposite directions. Optionally, the terminating ends  132  may be positioned below the side walls  122 ,  124 . 
     The end wall positioning ribs  172  on the end walls  126 ,  128  longitudinally position and/or center the contact assembly  136  within the contact assembly cavity  170 . The contact assembly  136  may be held in the contact assembly cavity  170  by an interference fit with the end wall positioning ribs  172  at opposite ends of the housing  106 . In the illustrated embodiment, the end wall positioning ribs  172  engage the dielectric carriers  140 . 
     The side wall positioning ribs  174  on the side walls  122 ,  124  laterally position and/or center the contact assembly  136  within the contact assembly cavity  170 . In the illustrated embodiment, the side wall positioning ribs  174  engage the dielectric carriers  140 . The contact assembly  136  may be held in the contact assembly cavity  170  by an interference fit with the press-fit ribs  176  at opposite sides of the housing  106 . 
       FIG. 11  is a partial sectional view of the receptacle connector  104  in accordance with an exemplary embodiment.  FIG. 11  illustrates one of the strengthening ribs  190  between the side walls  122 ,  124 . The strengthening rib  190  extends across the contact assembly cavity  170  to connect the first side wall  122  to the second side wall  124  at a location remote from the second end wall  128  and remote from the first end wall (not shown). The strengthening rib  190  ties the first and second side walls  122 ,  124  together to resist bowing outward of the first and second side walls  122 ,  124 . 
     In the illustrated embodiment, the strengthening rib  190  is positioned proximate to the securing features  184  of the housing  106  to ensure that the side walls  122 ,  124  do not bow outward in the area of the securing features  184 , which could otherwise cause the contact assembly  136  to disengage from the securing features  184 . The strengthening rib  190  is received in the channels  168  in the tops  152  of the dielectric carriers  140 . 
     In an exemplary embodiment, the strengthening rib  190  extends above the contact assembly cavity  170  into the card slot  112 . The strengthening rib  190  may extend above the tops  152  of the dielectric carriers  140 . The strengthening rib  190  extends across the card slot  112  above the contact assembly cavity  170 . The plug connector  105  (shown in  FIG. 1 ) may include a notch or groove to receive the top part of the strengthening rib  190 . Optionally, the strengthening rib  190  may serve to position the plug connector  105  in the card slot  112 . For example, the plug connector  105  may bottom out against the top of the strengthening rib  190  to define the fully mated position. 
     As shown in  FIG. 11 , the contacts  116  include interface bumps  230  at the mating ends  130  configured to interface with the plug connector  105 . The interface bumps  230  are convex shaped bends in the contacts  116  at the mating ends  130 . The interface bumps  230  extend beyond the interior surfaces  208 ,  210  into the card slot  112  to interface with the plug connector  105 . The interface bumps  230  define mating interfaces  232  configured to engage the plug connector  105 . Distal ends of the contacts  116  (for example, above the mating interfaces  232 ) are bent back into the contact channels  180  to prevent stubbing with the plug connector  105  when the plug connector  105  is loaded in the card slot  112 . The mating ends  130  may be deflected outward, such as into the contact channels  180 , when the plug connector  105  is loaded into the card slot  112 . 
     It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.