Patent Publication Number: US-11050200-B2

Title: Electrical connector with hermaphroditic terminal and housing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 62/696,764, entitled “Electrical Connector with Hermaphroditic Terminal and Housing” filed on Jul. 11, 2018, the content of which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     This application relates generally to electrical interconnection systems, such as those including electrical connectors, used to interconnect electronic assemblies. 
     Electrical connectors are used in many electronic systems. It is generally easier and more cost effective to manufacture a system as separate electronic sub-assemblies, such as printed circuit boards (“PCBs”), which may be joined together with electrical connectors. A known arrangement for joining several PCBs is to have one PCB serve as a backplane. Other PCBs, called “daughterboards” or “daughtercards”, may be connected to the backplane using connectors. Those connectors may be configured to carry signals such that the backplane routes signals between the daughtercards. Other connectors may be configured to carry power. 
     Conductive elements in power connectors may be configured for carrying power, such as by being wider to support higher currents. Signal conductors, in addition to being narrower, may be positioned relative to other signal conductors or wider conductive elements designated for connection to ground so as to provide a desired impedance in the signal conductors. Combo connectors, integrating in one connector both signal and power conductive elements are also known. Power connectors can be used to couple a supply of power from a subassembly connected to the backplane to the daughtercards also connected to the backplane. In other configurations, power connectors may be coupled to the supply of power via a cable. Those cabled connectors may mate with connectors on a daughtercard, on the backplane or on other components to which power is to be delivered. 
     Various techniques have been used to route power to the power connectors attached to a backplane. In some systems, the conductive elements in the power connectors may be attached to the backplane such that power is distributed through the backplane. In other systems, power may be routed to connectors via a busbar attached to the backplane or via cables. 
     SUMMARY 
     In accordance with one example embodiment, a power connector can include a first terminal. The first terminal can include a first flat portion and a first bent portion. The first bent portion can include a first end and a second end, the first end being coupled to the first flat portion and the second end comprising a first set of fingers comprising contact surfaces facing the first flat portion. 
     According to one aspect, the first flat portion has a first end and a second end with the first end of the first bent portion being coupled to the first flat portion at the first end of the first flat portion and the second end of the first flat portion extends beyond the second end of the first bent portion in a direction from the first end to the second end of the first flat portion. 
     According to another aspect, the first flat portion comprises a surface facing the first bent portion and the surface comprises at least one raised portion forming a contact surface. 
     According to another aspect, the first terminal further comprises a second flat portion, and a second bent portion comprising a first end and a second end, the first end being coupled to the second flat portion and the second end comprising a second set of fingers parallel to the second flat portion. 
     According to another aspect, the first flat portion, the second flat portion, the first bent portion and the second bent portion are integral metal members. 
     According to another aspect, the first flat portion, the second flat portion, the first bent portion and the second bent portion together have a cross section that is less than 10 mm square. 
     According to another aspect, the first terminal further comprises a band connecting the first flat portion to the second flat portion. 
     According to another aspect, a contact tail extends from the band or a bottom surface of the first flat portion or second flat portion. 
     According to another aspect, the contact tail is a cable mount contact tail, a right angle surface mount contact tail, a vertical surface mount contact tail, or a press fit contact tail. 
     According to another aspect, the first set of fingers comprises at least three fingers, each of the at least three fingers providing a contact surface facing the first flat portion and the second set of fingers comprises at least three fingers, each of the at least three fingers providing a contact surface facing the second flat portion. 
     According to another aspect, the power connector is in combination with a second power connector, the second power connector comprising: a second terminal comprising: a second flat portion, and a second bent portion comprising a first end and a second end, the first end being coupled to the second flat portion and the second end comprising a second set of fingers parallel to the second flat portion. 
     According to another aspect, the first terminal and the second terminal are mated to each other, with the second set of fingers of the second terminal contacting a surface of the first flat portion and the first set of fingers of the first terminal contacting a surface of the second flat portion. 
     According to another aspect, the second set of fingers provide at least three points of contact with the surface of the first flat portion and the first set of fingers provide at least three points contact with the surface of the second flat portion. 
     According to another aspect, at least two points of contacts are provided on the first flat portion and/or the second flat portion thereby providing sixteen points of contact when the first terminal and the second terminal are mated to each other. 
     According to another aspect, at least one of the first flat portion and second flat portion comprises a raised portion providing a contact surface pressing against a surface of the other of the first flat portion and second flat portion. 
     In another example embodiment, a power connector assembly can include a first power connector and a second power connector configured to mate with the first power connector. The first power connector can include a plurality of first terminals and the second power connector can include a plurality of second terminals. Each first terminal of the plurality of first terminals can include a first flat portion and a first bent portion. The first bent portion can include a first end and a second end, the first end being coupled to the first flat portion and the second end comprising a first set of fingers parallel to the first flat portion. Each second terminal of the plurality of second terminals can include a second flat portion and a second bent portion. The second bent portion can include a first end and a second end, the first end being coupled to the second flat portion and the second end comprising a second set of fingers parallel to the second flat portion. 
     According to one aspect, each first terminal of the first power connector is mated to a corresponding second terminal of the second power connector, with the second set of fingers of the second terminal contacting a surface of the first flat portion of the first terminal and the first set of fingers of the first terminal contacting a surface of the second flat portion of the second terminal. 
     According to another aspect, the second set of fingers provides at least three points of contact with the surface of the first flat portion and the first set of fingers provides at least three points of contact with the surface of the second flat portion. 
     According to another aspect, one of the first flat portion and second flat portion comprises a raised portion providing a contact surface pressing against a surface of the other of the first flat portion and second flat portion. 
     According to another aspect, each first terminal of the first power connector is mated to a corresponding second terminal of the second power connector and sixteen points of contact are provided between the mating terminals. 
     According to another aspect, the power connector assembly has a current capacity between 75 and 125 Amps. 
     According to another aspect, the first and second power connectors are cable mount power connectors. 
     According to another aspect, the first power connector is a cable mount power connector and the second power connector is a right angle surface mount power connector. 
     According to another aspect, the first power connector is a cable mount power connector and the second power connector is a vertical surface mount power connector. 
     According to another aspect, the first power connector is a vertical surface mount power connector and the second power connector is a right angle surface mount power connector. 
     In yet another example embodiment, a method of manufacturing a terminal for a power connector is provided. The method can include stamping from a sheet of metal a blank comprising a first elongated portion and a second elongated portion comprising a plurality of fingers, bending the second elongated portion to be parallel with the first elongated portion, and forming the second elongated portion such that each of the fingers comprises a convex portion facing the first elongated portion. 
     According to one aspect, the method further comprises forming a raised portion on the first elongated portion. 
     According to another aspect, the blank comprises a third elongated portion and a fourth elongated portion; and the method further comprises: forming in the fourth elongated portion a plurality of fingers, and bending the fourth elongated portion such that the plurality of fingers are parallel with the third elongated portion, and each of the plurality of fingers comprises a convex portion facing the third elongated portion. 
     The foregoing aspects may be used alone, or any number may be used together, in any of the embodiments described herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of example embodiments of the application, will be better understood when read in conjunction with the appended drawings, in which there is shown in the drawings example embodiments for the purposes of illustration. It should be understood, however, that the application is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
         FIG. 1A  is a perspective view of two exemplary hermaphroditic power connectors when mated, according to one embodiment. 
         FIG. 1B  is a front, right side perspective view of exemplary connector  110  of  FIG. 1A  when unmated. 
         FIG. 1C  is a front, right side perspective view of exemplary connector  120  of  FIG. 1A  when unmated. 
         FIG. 1D  is a perspective view of a step of terminating a cable with a terminal in accordance with some embodiments. 
         FIG. 2  illustrates an example terminal of a power connector, according to one embodiment. 
         FIGS. 3A and 3B  are top plan views of two exemplary terminals of power connectors shown unmated in  FIG. 3A  and mated in  FIG. 3B , according to some embodiments. 
         FIGS. 3C and 3D  are perspective views of the exemplary terminals of power connectors of  FIG. 3A  and  FIG. 3B . 
         FIG. 4A  is a perspective view of two exemplary hermaphroditic surface mount, parallel power connectors, according to some embodiments. 
         FIG. 4B  is perspective view revealing the mating and mounting interfaces of one of the power connectors of  FIG. 4A . 
         FIG. 4C  is a perspective view revealing the back and the mounting interface of one of the power connectors of  FIG. 4A . 
         FIG. 4D  is a perspective view of a surface mount terminal of the power connector of  FIGS. 4A-4C . 
         FIG. 5A  is a perspective view of two exemplary hermaphroditic surface mount, mezzanine power connectors, according to some embodiments. 
         FIG. 5B  is perspective view revealing the mating interface of one of the power connectors of  FIG. 5A . 
         FIG. 5C  is a perspective view revealing the mounting interface of one of the power connectors of  FIG. 5A . 
         FIG. 5D  is a perspective view of a surface mount terminal of the power connector of  FIGS. 5A-5C . 
         FIG. 6A  is a perspective view revealing the mating and mounting interfaces of an exemplary hermaphroditic power connector with press fit terminals, according to some embodiments. 
         FIG. 6B  is a perspective view revealing the back of the power connector of  FIG. 6A . 
         FIG. 6C  is a lower, left side perspective view of an exemplary hermaphroditic press fit power terminal, according to some embodiments. 
         FIG. 6D  is a bottom, right side perspective view of the exemplary hermaphroditic press fit power terminal of  FIG. 6C . 
         FIG. 6E  is a lower, left side perspective view of an exemplary hermaphroditic press fit power terminal, according to an alternative embodiment configured for carrying more current than the terminal of  FIG. 6C . 
         FIG. 6F  is a bottom, right side perspective view of the exemplary hermaphroditic press fit power terminal of  FIG. 6E . 
         FIGS. 7A-7C  illustrate different power connector configurations, according to some embodiments. 
         FIGS. 8A-8E  illustrate example blanks used to form power terminals associated with different types of power connectors, according to some embodiments. 
         FIGS. 9A and 9B  are perspective views from the left front and right side, respectively, of exemplary power terminals with one or more helper springs during assembly. 
         10 A- 10 B are side views of exemplary power terminals with one or more helper springs, shown in phantom, during assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the present disclosure relate to improved interconnection systems with a low-cost power connector assembly. 
     The inventors have recognized and appreciated techniques for designing power connectors that are capable of carrying large amounts of current in a small volume, at low manufacturing cost. 
     The inventors have recognized and appreciated that hermaphroditic power connectors, where the housing and/or the terminals on both sides of the connector assembly have a like shape, can be manufactured with the same tooling and machinery such that fewer stamping or folding dies are required to make both mating connectors. Accordingly, manufacturing costs of the connector assembly are low. 
     The inventors have further recognized and appreciated designs for such terminals that can carry large amounts of current and further that such current carrying capacity can be provided in a small volume. A large current capacity may be achieved with a larger number of contact points between connectors. A density of contact points may be provided with terminals having a blade and multiple fingers facing the blade. Upon mating to a like terminal, the blade of one terminal may fit between the fingers and blade of the other terminal. A contact surface on each finger may provide a low resistance contact to the blade of the mating terminal. The fingers may also exert spring force pressing the blades together. One or more contact surfaces on one or both of the blades may provide further low resistance points of contact between the terminals. 
     In some embodiments, a terminal may have two or more mating regions, each with a blade and opposing fingers. In an exemplary embodiment, a terminal with two such mating regions may provide 16 points of contact: 3 points of contact associated with 3 fingers contacting a blade in each mating region, providing 6 points of contact on the fingers on the 2 mating terminals. Two additional points of contact may be provided on the blades. With two mating regions, each with 8 points of contact, a total of 16 points of contact are provided between the mating terminals. 
     In accordance with some embodiments, each terminal, with multiple points of contact may be stamped and formed from the same sheet of metal. The fingers and blades may initially be stamped as elongated members in the same plane. The fingers may then be folded to be parallel to the blades. Where two mating regions are provided per terminal, similar structures may be stamped from the same sheet of metal, with a band connecting the mating regions. Structures that are formed into contact tails for the terminal may be integrally formed with the band. 
     Referring to  FIGS. 1A-1D , an example power connector assembly  100  can include hermaphroditic power connectors. In the embodiment illustrated in  FIG. 1A , the power connectors are configured as cable connectors of which a first cable mount power connector  110  is mated to a second cable mount power connector  120 . Power connectors  110  and  120  may have like structures, with the housing and the terminals of each connector having like shapes. 
     As shown in  FIGS. 1B and 1C , each of the first and second cable mount power connectors  110 ,  120  can include multiple terminals supported by a housing. For example, the first cable mount power connector  110  can include first terminals  112   a ,  112   b ,  112   c , and  112   d  that are supported by housing  114 . Similarly, the second cable mount power connector  120  can include second terminals  122   a ,  122   b ,  122   c , and  122   d  that are supported by housing  124 . Each first terminal of the first cable mount power connector  110  is configured to mate with a corresponding second terminal of the second cable mount power connector  120 . In the embodiment illustrated, each of the terminals has two mating regions. Each mating region, is illustrated as comprising a blade and a plurality of contact fingers. It should be appreciated that power terminals may be made with more or fewer mating regions, such as one mating region. Moreover, a connector may have more or fewer than four terminals. 
     The housings  114  and  124  may each have complimentary features to facilitate mating of like housings. Referring to  FIG. 1B , housing  114  has complimentary alignment features. In the illustrated embodiment, the complimentary alignment features include an opening  130  and protrusion  132 , sized to fit within opening  130 . Protrusion  132  and/or the mouth of opening  130  may be tapered to facilitate alignment. When a mating connector with a like housing, rotated 180 degrees, such as connector  120  ( FIG. 1C ) is mated with connector  110 , an opening  130  on connector  110  will receive a protrusion  132  from the mating connector. Likewise, protrusion  132  of connector  110  will fit within the opening  130  of the mating connector. 
     Housings  114  and  124  may also include features that enclose the terminals while still allowing mating of like housings. In the embodiment illustrated in  FIG. 1B , a top surface has first and second tabs  140  and  142 . Each of the tabs  140  and  142  is positioned above the mating regions of a portion of the plurality of terminals in the connector. Similar tabs (not numbered) are positioned below the terminals such that the terminals are positioned behind tabs that can block unwanted contact to the terminals from the top and bottom. Other portions of the housing block unwanted contact to the terminals from the sides and back, leaving the contacts exposed at a mating interface. 
     Tabs  140  and  142  may be sized and positioned to enable mating of like connectors. In the embodiment illustrated, tabs  140  and  142  are symmetrically positioned around a lateral centerline C L1 . However, tabs  140  and  142  are positioned at different distances from a transverse centerline C L2 . The difference in distances equals or slightly exceeds the thickness of tab  140 , which is further from the transverse centerline C L2 . When connector  110  is mated to a connector with a like housing, tab  140  will align, in the lateral direction, with tab  142  of the like housing. However, tab  140  will be above tab  142  of the like housing, such that connector  110  may be mated with the connector with the like housing, as shown in  FIG. 1A . A similar arrangement of tabs interlock at the bottom of the mating connectors. 
     Referring to  FIGS. 1B and 1C , each of the first terminals  112   a - 112   d  may be attached, respectively, to an electrical cable  116   a - 116   d  so as to place the electrical cable in electrical communication with the terminal. Each of the second terminals  122   a - 122   d  may be attached, respectively, to an electrical cable  126   a - 126   d  so as to place the electrical cable in electrical communication with the terminal. In some embodiments, the first/second terminals may be attached to the respective electrical cables by welding or crimping. 
       FIG. 1D  illustrates a terminal  112   a , which may be illustrative of terminals  112   a  . . .  112   d  or  122   a  . . .  122   d , being attached to an electrical cable  116   a , which may be illustrative of cables  116   a  . . .  116   d  or  126   a  . . .  126   d , for example, by welding, brazing, soldering. In the embodiment illustrated, the conductors within cable  116   a  may be fused into a lug  118 , such as by welding. A welded interface between lug  118  and terminal  112   a  may provide a low resistance contact to the terminal, though any suitable attachment mechanism may be used. In some embodiments, cables, such as cable  116   a  illustrated in  FIG. 1D  may be a large gauge wire, such as a wire having an AWG of less than 8 AWG, such as 4 AWG. Such a wire, when terminated with a terminal as illustrated in  FIG. 1D  may provide a cable assembly with a current carrying capacity in excess of 75 Amps, and may be between for example, 75 and 125 Amps. The current carrying capacity may be determined in any suitable way, including using known rating systems that measure current that produces a temperature rise that is less than a specified maximum value. As a specific example, the current carrying capacity may be determined by the current that yields a temperature rise of less than 30-degree Centigrade. 
     The configurations described herein enable terminals to provide such large current carrying capacities in a relatively small volume. A terminal as described herein with two blades and two sets of fingers may fit in a small volume. The mating portion, for example, may have a square cross section that is 20 mm per side, or in some embodiments, less than 15 mm per side, or less than 10 mm per side, or equivalent non-square area. In some embodiments, the cross section may be between 5 and 15 mm per side or between 5 and 10 mm per side, and still provide current carrying capacity in excess of 75 Amps, as described above. However, it should be appreciated that other current capacities are possible or that smaller sizes are possible. 
     Each of the first terminals  112   a - 112   d  and second terminals  122   a - 122   d  have a like shape, as depicted by terminal  200  in  FIG. 2 , for example. In the example of  FIG. 2 , terminal  200  has a mating portion  202  with two mating regions  210 ,  220  and a mounting portion  204  having tails  206  and  208 . In the embodiment illustrated, tails  206  and  208  are configured to electrically connect to an electrical cable. Accordingly, terminal  200  is configured for use in a cable connector as illustrated in  FIGS. 1A  . . .  1 D. However, terminal  200  may mate with terminals with tails configured for use in other connector configurations that have mating portions of the same configuration as mating portion  202 . 
     Mating region  210  may include a first blade  212  and a first set of fingers  214 . Here, blade  212  is a substantially flat, though a forward edge may be tapered, coined or otherwise shaped to, upon mating with a like terminal, pass between similar fingers and a similar blade of the mating terminal. 
     Fingers  214  have mating contact surfaces facing blade  212 . The distal tips of fingers  214  may be curled away from blade  212 . Such a configuration may facilitate mating with a like terminal, as it will facilitate insertion of a blade of a like terminal between blade  212  and fingers  214 . 
     In the embodiment illustrated, there are three fingers  214  and one blade  212 . however, it should be appreciated that a terminal may be formed with more than one blade and/or more or less than three fingers. 
     Upon mating with a like terminal, a corresponding blade from the mating connector may pass between fingers  214  and blade  212 . Fingers  214  may press against the blade from the mating terminal, both establishing points of contact between fingers  214  and the blade of the mating terminal and pressing the blade of the mating terminal against blade  212 . 
     In some embodiments, blade  212  and fingers  214  may be formed from a unitary sheet of metal. In such a configuration, fingers  214  may be cut in a first bent portion  216 , which is integral with blade  212 , but is bent so as to position fingers  214  facing blade  212 . The first bent portion  216  may include a first end  232  and a second end  234 , the first end  232  being coupled to blade  212  and the second end  234  including the fingers  214  parallel to blade  212 . Blade  212  may include a first end  236  and a second end  238  with the first end  232  of the first bent portion  216  being coupled to the blade  212  at the first end  236  of blade  212 . The second end  238  of blade  212  may extend beyond the second end  234  of the first bent portion  216  in a direction from the first end  236  to the second end  238  of blade  212 . In some embodiments, the first set of fingers  214  may include at least three fingers, each of the at least three fingers providing a contact surface facing blade  212 . However, it should be appreciated that set of fingers  214  may include more or less than three fingers. 
     Similarly, mating region  220  may include a second blade  222  parallel to the first blade  212  and a second set of fingers  224  on a second bent portion  226 , the second set of fingers  224  being parallel to the second blade  222 . The configuration of the second blade  222 , the second bent portion  226 , and the second set of fingers  224  may be similar to the configuration of the first blade  212 , first bent portion  216 , and the first set of fingers  214  described above. In some embodiments, the second set of fingers  224  may include at least three fingers, each of the at least three fingers providing a contact surface facing the second flat portion  222 . However, it should be appreciated that the second set of fingers  224  may include more or less than three fingers. 
     In some embodiments, mating regions  210  and  220  may be formed from an integral sheet of metal. In such an embodiment, terminal  200  may include a first band  240  connecting a first surface  242  of blade  212  and a first surface  244  of the second blade  222 . Terminal  200  may further include a second band  250  (as shown in  FIG. 1D ) connecting a second surface  252  of blade  212  and a second surface  254  of blade  222 . 
     In some embodiments, tails  206 ,  208  of the mounting portion  204  extend from the first and second bands  240 ,  250 , respectively. Each of the tails  206 ,  208  of the mounting portion  204  may represent a cable mount contact tail. Referring to  FIGS. 1D and 2 , terminal  200  may include a first transition region  260  that extends from a front end of tail  206  of mounting portion  204  to a rear end  241  of the first band  240  and a second transition region  262  that extends from a front end of tail  208  of mounting portion  204  to a rear end  251  of the second band  250 . The first transition region  260  may be curved downwards along at least a portion of its length between the rear end  241  of the first band  240  and the front end of tail  206 . The second transition region  262  may be curved upwards along at least a portion of its length between the rear end  251  of the second band  250  and the front end of tail  208 . The first and second transition regions  260 ,  262  may be configured to transmit electrical current between the mounting portion  204  and the mating portion  202 , for example, from the mounting portion  204  to the mating portion  202 . 
       FIGS. 3A and 3B  depict top plan views of a first terminal, such as terminal  112   a , of the first cable mount power connector  110  and a second terminal, such as terminal  122   a , of the second cable mount power connector  120 . The first terminal  112   a  of the first cable mount power connector  110  is configured to mate with a corresponding second terminal  122   a  of the second cable mount power connector  120 . In the embodiment illustrated, each of the first terminal  112   a  and second terminal  122   a  may be configured like terminal  200  ( FIG. 2 ). 
       FIGS. 3A and 3B  illustrate the configuration of the first and second terminals prior to and after being mated to each other. In  FIGS. 3A and 3B , first and second blades of terminal  112   a  are labeled as  212 - f  and  222 - f , respectively; the first and second sets of fingers of terminal  112   a  are labeled as  214 - f  and  224 - f , respectively; the first and second blades of terminal  122   a  are labeled as  212 - s  and  222 - s , respectively; and the first and second set of fingers of terminal  122   a  are labeled as  214 - s  and  224 - s.    
     Upon mating, 1) the first blade  212 - f  of the first terminal  112   a  fits between the second blade  222 - s  and the second set of fingers  224 - s  of the second terminal  122   a , with the second set of fingers  224 - s  of the second terminal  122   a  contacting a surface of first blade  212 - f  of the first terminal  112   a  and the first set of fingers  214 - f  of the first terminal  112   a  contacting a surface of the second blade  222 - s  of the second terminal  122   a , and 2) the second blade  222 - f  of the first terminal  112   a  fits between the first blade  212 - s  and the first set of fingers  214 - s  of the second terminal  122   a , with the first set of fingers  214 - s  of the second terminal  122   a  contacting a surface of the second blade  222 - f  of the first terminal  112   a  and the second set of fingers  224 - f  of the first terminal  112   a  contacting a surface of the first blade  212 - s  of the second terminal  122   a.    
     The fingers and the blades of each of the first and second terminals may have multiple points of contact, forming, in the aggregate a low resistance, separable connection between the first and second terminals. Points of contact may be formed between the fingers of one terminal and a blade of a mating terminal. Additionally, points of contact may be formed between blades of the mating terminals, providing additional points of contact that provides an even lower resistance, separable connection. 
     Contact surfaces on fingers  214 - s  and  224 - f  may be formed on concave segments bent into the fingers and/or by selectively coating a suitable contact coating on those portions. Similarly, contact surfaces on fingers  214 - f  and  224 - s  may be formed on concave segments bent into the fingers and/or by selectively coating a suitable contact coating on those portions. Examples of suitable contact coatings include soft metals such as gold or silver and/or metals that are resistant to tarnishing such as nickel or tin, or alloys of any of the above. Portions of the surfaces of the blades against which the fingers press may similarly have a suitable contact coating applied thereto. 
     Contact surfaces on blades  212 - s  and/or  222 - f  for facilitating contact between blades may be formed in any suitable way. In some embodiments, contact surfaces may be formed using techniques such as by embossing dimples, bumps or other raised portion in one or both of the blades, and/or by coating a suitable contact metal on selective portions of the blade. In some embodiments, contact surfaces may be formed on opposing sides of each of blades  212 - s  and  222 - f . On a surface facing respective fingers, contact surfaces may be formed as projections. On an opposite surface, contact surfaces may be formed by applying a coating. Such a contact surface may provide a low resistance contact with fingers of a mating terminal. Projections, on the other hand, may provide a low resistance contact to a blade of a mating terminal. Similar contact surfaces may be formed on blades  212 - f  and/or  222 - s.    
     Accordingly, a contact surface on each finger of the first set of fingers  214 - f  of the first terminal  112   a  may provide a low resistance contact to the second blade  222 - s  of the second terminal  122   a . A contact surface on each finger of the second set of fingers  224 - f  of the first terminal  112   a  may provide a low resistance contact to the first blade  212 - s  of the second terminal  122   a . A contact surface on each finger of the first set of fingers  214 - s  of the second terminal  122   a  may provide a low resistance contact to the second blade  222 - f  of the first terminal  112   a . A contact surface on each finger of the second set of fingers  224 - s  of the second terminal  122   a  may provide a low resistance contact to the first blade  212 - f  of the first terminal  112   a.    
     Moreover, the bent portions of fingers  214 - s  and  224 - f  may provide spring forces on blades  222 - f  and  212 - s , urging the blades together. This spring force may provide one or more points of contacts between blades  222 - f  and  212 - s . Likewise, fingers  214 - f  and  224 - s  may provide spring forces on blades  222 - s  and  212 - f , urging the blades together. This spring force may provide one or more points of contacts between blades  222 - s  and  212 - f.    
     In some embodiments, the first and second set of fingers of the first terminal  112   a  may have at least three fingers, providing at least three points of contact, respectively, with surfaces of the second and first blades of the second terminal  122   a . Similarly, the first and second set of fingers of the second terminal  122   a  may have at least three fingers providing at least three points of contact, respectively, with surfaces of the second and first blades of the first terminal  112   a . Therefore, terminals  112   a ,  122   a  with two mating regions may provide three points of contact associated with each of two blades on the terminal, providing six points of contact on the fingers in each mating region. 
     In some embodiments, one or more contact surfaces on one or both of the blades of each of the first and second terminals  112   a ,  122   a  may provide further low resistance points of contact between the terminals. For example,  FIG. 3C  illustrates the second blade  222 - s  of the second terminal  122   a  including at least one dimple  302 . Here, two dimples  302  are illustrated. An inner surface of the second blade  222 - s  (i.e., a surface of the second blade  222 - s  facing the second bent portion  224 - s ) may include a raised portion as a result of dimple  302 , forming a contact surface. Upon mating, the dimple  302  provides a contact surface pressing against a surface of the first blade  212 - f  of the first terminal  112   a . Similar dimples may be provided on the first blade of the second terminal  122   a  and/or the first and second blades of the first terminal  112   a  without departing from the scope of this disclosure. 
     The terminals may additionally include retention features. In the example embodiment of  FIG. 3C , retention features are formed as tabs  304  cut in the metal forming the terminal. In this example, the tabs are cut in an outwardly facing surface of the terminal, here a tab in blade  222 - s  is visible. Tab  304  has a raised distal end facing in a direction opposite the insertion direction of the terminal into a housing. Additional retention features may be formed in other surfaces of the terminal that contact a surface of a connector housing. It should be appreciated that tabs may be used in place of dimples to formed raised surfaces of contact structures. However, the retention features may not include a contact coating. Additionally, while a retention feature is positioned adjacent a surface of a housing such that it may engage the housing, a raised portion serving as a contact structure faces an open space that may receive a mating contact portion from a mating terminal. 
     In some embodiments, a pair of terminals (e.g., terminals  112   a  and  122   a ), each having two mating regions (e.g., mating regions  210 ,  220 ), may provide sixteen points of contact when mated: three points of contact associated with each of two blades/flat portions on one terminal, providing six points of contact on the fingers in each mating region. Two additional points of contact in the form of dimples may be provided on the blades/flat portions. With two mating regions, each with 8 points of contact, a total of 16 points of contact are provided between the mating terminals. For terminals with only one mating region, 8 points of contact may be provided. Accordingly, regardless of the specific configuration, terminals as described herein may provide a high density of contact points in comparison to conventional power terminals. 
     It should be appreciated that terminals with mating contact portions providing multiple points of contact as described herein may be configured for use in connector configurations other than cable connectors. In some embodiments, the terminals for such connectors may have a different mounting portion than described above for mounting portion  204 , but the mating portion may have the same configuration as mating portion  202 . 
       FIGS. 4A-6F  illustrate other hermaphroditic power connector designs, where the housing and the terminals on both sides of the connector assembly have a like shape. For example,  FIGS. 4A-4C  depict a power connector assembly  400  including hermaphroditic right angle surface mount PCB (printed circuit board) connectors  402 ,  404  configured to mate to each other. As illustrated, the housings have alignment and mating features that provide a mating interface with the same configuration as in  FIG. 1B . 
     Each of the connectors  402 ,  404  may include a plurality of terminals having a like shape, such as, terminal  410  depicted in  FIG. 4D . The mating portion  420  of the terminal  410  may be similar to the mating portions of terminal  112   a  or  122   a . The mating portion  420  may include one or more dimples on each of the blades. Inner surfaces of the blades may include one or more raised portions that result from one or more dimples, forming one or more contact surfaces. Additionally, the mounting and/or mating portions may include retention features, tapers, coating and other features as described herein in connection with other embodiments. 
     The mounting portion  430  of the terminal  410  may include the tails  436 ,  438  extending from the first and second bands  440 ,  450 , respectively. In the illustrated embodiment, each of the tails  436 ,  438  of the mounting portion  430  is shaped to provide a right angle surface mount contact tail. Such a contact tail has a pad configured for surface mount soldering to a printed circuit board or similar substrate. 
     In the embodiment of  FIG. 4D , terminal  410  is formed from an integral sheet of metal such that the mating portion  420  and the mounting portion  430  are mechanically and electrically connected via that sheet of metal. The pad at the distal end of tail  436  comprises an unbroken pad stamped from that sheet of metal. The pad at the distal end of tail  438 , however, is formed from two portions that are folded to be adjacent and planar. In soldering the pad of tail  438  to a substrate, those portions will become electrically and mechanically joined, and will have a high current carrying capacity. 
       FIGS. 5A-5C  depict a power connector assembly  500  including hermaphroditic vertical surface mount PCB (printed circuit board) connectors  502 ,  504  configured to mate to each other. Each of the connectors  502 ,  504  may include a plurality of terminals having a like shape, such as, terminal  510  depicted in  FIG. 5D . The mating portion  520  of the terminal  510  may be similar to the mating portions of terminal  112   a  or  122   a.    
     The mounting portion  530  of the terminal  510  may include tails  536 ,  538  extending from the first and second bands  540 ,  550 , respectively. Each of the tails  536 ,  538  of the mounting portion  530  may be shaped for a surface mounting, and are here shown to have pads at their distal ends for that purpose. In contrast to the embodiment of  FIG. 4D , terminal  510  has tails shaped to provide a vertical surface mount connector. 
       FIGS. 6A and 6B  illustrate terminals configured for yet another mating configuration. In this example, the terminals are configured to enable a hermaphroditic press fit PCB (printed circuit board) connector. Connectors  602 ,  604  have like construction and are configured to mate to each other. Each of the connectors  602 ,  604  may include a plurality of terminals having a like shape, such as, terminal  610  depicted in  FIGS. 6C and 6D . The mating portion  620  of the terminal  610  may be similar to the mating portions of terminal  112   a  or  122   a . The mating portion  620  may include one or more dimples on each of the blades. Inner surfaces of the flat portions may include one or more raised portions of the one or more dimples forming one or more contact surfaces. Other features described in connection with other embodiments may also be included, such as retention features and contact coatings. However, it should be appreciated that variations in shape and position of those features may be made. For example, retention tabs may be provided at an edge of a blade in addition to or instead of retention tabs  304  ( FIG. 3C ) in a central portion of a blade. 
     The mounting portion  630  of the terminal  610  may include at least a tail  638  extending from bottom surfaces of first and second blades of the mating portion  620 . At least the tail  638  of the mounting portion  630  may have one or more press fits. In the embodiment, press fits extend from both tails  636  and  638 . Eight press fits are illustrated, 4 on each of tails  636  and  638 . However, more or fewer press fits may be included. Here, the press fits have an “eye of the needle” shape such that press fits will compress when inserted in a hole in a printed circuit board, generating a force against walls of the hole to make both electrical and mechanical contact between the terminal  610  and the printed circuit board. 
     In some embodiments, the solder tail density may be increased by adding two middle rows as shown in terminal  650  of  FIGS. 6E and 6F . For example, the number of press fit tails can be increased to 16, which doubles the mechanical retention to the PCB and halves the resistance of the contact between the terminal and the PCB to which it is mounted in comparison to terminal  610 . As can be seen from a comparison of  FIGS. 6C and 6D  to  FIGS. 6E and 6F , additional press fits may be formed on tails  656  and  658  by stamping those tails to be longer than their finished configuration and then, forming folds  670  and  672 , such that the press fits of each tail may be in parallel rows. 
     In some embodiments, as illustrated in  FIGS. 7A-7C , the different styles of power connectors described herein may be mated to each other because of the similar design of the mating regions of the terminals across the different power connectors.  FIG. 7A  illustrates a cable mount connector mated with a right angle surface mount connector.  FIG. 7B  illustrates a cable mount connector mated with a vertical surface mount connector.  FIG. 7C  illustrates a vertical surface mount connector mated with a right angle surface mount connector. 
     Example methods of manufacturing terminals for power connectors are provided. Known metal stamping, plating and forming techniques may be used to form terminals with the shape described herein. For example,  FIG. 8A  illustrates a blank  800  stamped from a sheet of metal. In this example, the blank is shaped to be formed into one of the first or second terminals  112   a - d ,  122   a - d  of the first and second power connectors  110 ,  120 . Blanks, shaped to form terminals in other configurations may be manufactured through a similar process, but with different shape to the portions that will be formed into the terminal tails. The blank  800  may be made of electrically conductive material, for instance, copper alloy or other metal, including for example phosphor bronze. In accordance with some embodiments, the material may have a thickness between 0.5 and 1.5 mm, or between 0.7 and 1.0 mm in some embodiments or 0.8 mm+/−5% in some embodiments. Such a blank may provide sufficient stiffness to form blades but also fingers that generate a mating force. Moreover, such a blank, when formed into a terminal as described herein, may provide a sufficiently low resistance between the contact tails and mating contacts to support currents in excess of 70 A, or, in some embodiments, between 75 and 125 A with less than a 30 degree centigrade temperature rise. 
     The blank  800  may include a first elongated portion  812 , a second elongated portion  814 , a third elongated portion  816 , and a fourth elongated portion  818 . A first set of fingers  822  may be formed in the second elongated portion  814  and a second set of fingers  824  may be formed in the fourth elongated portion  818 . Some or all of the portions of the blank  800  may be plated or otherwise coated with a contact coating. The coating may be applied to the upper surface  833  or to the opposing surface (not shown) to provide contact surfaces in the desired location when the blank is formed into a terminal. 
     In the illustrated embodiment, the first elongated portion  812  is aligned with the second elongated portion  814 . The second elongated portion  814  may be bent to be parallel with the first flat elongated portion  812 . First elongated portion  812  may be shaped to provide a blade as described herein and the second elongated portion may be shaped to provide a first set of fingers  822 . 
     Third elongated portion  816  and fourth elongated portion  818  may be aligned such that the fourth elongated portion  818  may be bent to be parallel with the third elongated portion  816 . Third elongated portion  816  may be shaped to provide a blade and fourth elongated portion  818  may be shaped to provide a second set of fingers  824 . Each finger in the first set of fingers  822  may include a convex portion facing the first elongated portion  812  and each finger in the second set of fingers  824  may include a convex portion facing the third elongated portion  816 . In some embodiments, a raised portion  826  may be formed on the first elongated portion  812 , the third elongated portion  816 , or both. The raised portions may be formed by embossing dimples in elongated portion  816  or in any other suitable way. Similarly, retention tabs and other desired features may be formed in elongated portion  816  and/or any other portion of the blank. 
     Blank  800  includes portions that, when the blank is formed into a terminal provide tails. Here, blank  800  includes a band, joining elongated portions  812  and  816 , and providing a connection for portions that are formed into tails for the terminal. In the embodiment illustrated in  FIG. 8A , blank  800  includes portions that maybe formed into tails for attachment to a cable, as shown in  FIG. 2 . Portion  836 , for example, may be formed into the shape of tail  206 . Portions  838 A and  838 B may be formed to, together, form tail  208 . 
       FIGS. 8B-8E  illustrate blanks  810 ,  820 ,  830 ,  840  used for forming various terminals, such as, terminal  410 , terminal  510 , terminal  610 , and terminal  650 , respectively. Each of the blanks  810 ,  820 ,  830 ,  840  have four elongated portions and first and second set of fingers similar to blank  800 . The terminals  410 ,  510 ,  610 , and  650  may be formed in a manner similar to terminals  112   a ,  122   a , for example, by bending the elongated portions with the fingers to be parallel with the flat elongated portions. The blanks, however, may include portions  854 ,  864 ,  874 A and  874 B and  884 A and  884 B that, when formed, make up the mounting portion of the terminal. 
     In some embodiments, each of the terminals has at least one set of fingers facing a blade. Such a terminal is configured to receive and mate with at least a blade inserted between the fingers and the blade. For example, when terminal  112   a  mates with terminal  122   a , blade  222 - s  fits between fingers  214 - f  and blade  212 - f . In that configuration spring force generated by fingers  214 - f  both provides a mating force between fingers  214 - f  and blade  222 - s  and presses blade  222 - s  against blade  212 - f  so that there are multiple points of contact. 
     In the embodiment illustrated, in which like terminals are mated, fingers  224 - s  similarly supply a spring force such that fingers  224 - s  press against blade  212 - f  and draw blades  212 - f  and  222 - s  together to increase the force between. This increase in force between blades  212 - f  and  222 - s  results from mating like terminals that both have blades and fingers. Increase in mating force reduces contact resistance and enables a connector formed with such terminal to operate at high currents, such as between 75 and 100 Amps per terminal, as described herein. 
     The inventors have realized that in some instances normal forces exerted by the fingers may not be sufficient depending on the base material chosen for the terminal. In some embodiments, helper springs may be added to the terminals to increase the normal force. For example, as shown in  FIGS. 9A-9B , one or more helper springs  912 ,  914  may be added to the first and/or second terminals, such as, terminal  112   a ,  122   a . In the example of  FIG. 10A , helper spring  912  may be designed to slip over the first blade  212  and first bent portion  216  of a terminal (e.g., terminal  112   a ) and helper spring  914  may be designed to slip over the second blade  222  and second bent portion  226  of the terminal. The helper spring  912  may have a shape similar to the combined bent shape of the first blade  212  and first bent portion  216 . The helper spring  914  may have a shape similar to the combined bent shape of the second blade  222  and second bent portion  226 . The helper springs may have a higher spring constant than the fingers of the terminal. A higher spring constant may be achieved, for example, using a different material than is used to form the terminal. A suitable material may be readily selected as the material may have a higher resistance than the material used to form the fingers of the terminal, without impacting the current carrying capacity of the terminals. 
       FIG. 10B  illustrates the arrangement of the helper springs  912 ,  914 , where a first portion  922  of the helper spring  912  substantially overlaps the first bent portion  216  and the first set of fingers  214  and the first portion  932  of the helper spring  914  substantially overlaps the second bent portion  226  and the second set of fingers  224 . 
     It will be appreciated that while  FIGS. 9A, 9B, 10A, and 10B  depict helper springs added to terminals  112   a ,  122   a , the helper springs may also be added to terminals with other configurations, such as terminals  410 ,  510 ,  610 , and  650 , without departing from the scope of this disclosure. 
     It should be understood that aspects of the invention are described herein with reference to certain illustrative embodiments and the figures. The illustrative embodiments described herein are not necessarily intended to show all aspects of the invention, but rather are used to describe a few illustrative embodiments. Thus, aspects of the invention are not intended to be construed narrowly in view of the illustrative embodiments. In addition, it should be understood that aspects of the invention may be used alone or in any suitable combination with other aspects of the invention.