Abstract:
This approach generally pertains to a miniature receptacle terminal with a connection section and a mating section. The mating section has a dual primary contact beam component that includes contact springs having resilient contact beams and a secondary beam. Each contact beam has a contact point opposing the opposing wall of the receptacle terminal, which can include a contact bump. A distributed and balanced contact force is exerted on a male terminal pin that is inserted between the primary contact beams and the contact bumps. Overstress protection of the contact spring is provided and the terminal is economical to produce.

Description:
BACKGROUND OF THE INVENTION 
     This present invention generally pertains to receptacle terminals and more particularly to improved miniature receptacle terminals. These receptacle terminals are structured to enhance pin contact engagement or holding force. 
     DESCRIPTION OF BACKGROUND ART 
     The automotive market is shifting to downsized, small-footprint types of receptacle terminals. It is generally known that the contact engagement or holding force of receptacle terminals becomes weaker as the terminals become smaller since the contact springs become proportionally smaller. Attempts have been made to increase the contact engagement or holding force of smaller contact springs by stacking smaller contact springs together, for example, employing two contact springs together to double the combined spring thickness in an attempt to double the contact force. Variation of tolerance due to multiple springs, however, often results in unacceptably large variations of contact force and manufacturing control is complicated. Attempts have also been made to reinforce the thickness of the contact springs employing dimples or beads but this approach has also meet with limited success. 
     Prior art approaches that have not recognized the positives that could be gained by seeking to achieve the objectives or teach solutions as accomplished by the present approach include U.S. Pat. No. 4,973,271 that pertains to a low insertion force electrical contact female terminal comprised of a main body portion with a resilient contact section and a separate movable support member. The movable support member is positioned under the resilient contact portion to minimize insertion force during mating. After mating, the movable body support member is moved to a second position to maximize force and maintain a strong connection. U.S. Pat. No. 5,226,842 relates to a female terminal for connecting to a male terminal having a terminal body with an opening through which the male terminal is inserted in a wire connecting part for connecting to wires. A separate flexible leaf spring element is mounted on the terminal body for pressing the male terminal against the terminal body. Stop means are provided in the terminal body for restraining the center portion of the flex element in a pre-load condition prior to the insertion of the male terminal. U.S. Pat. No. 6,244,910 relates to a box receptacle terminal formed from a stamped blank with a cantilevered contact-spring. The contact-spring is outwardly deflected relative to the receptacle base when mated with a male contact such as a blade or pin terminal. 
     Other prior art includes the following. U.S. Pat. No. 6,305,992 relates to an electrical contact having a conductor connector region for connection to an electrical conductor wire and a contact region for making contact with a complementary pin contact. The contact region is essentially designed in the form of a box. The contact region has a contact spring arm extended forward that can be pre-stressed. A supporting second spring arm is positioned above the contact spring arm to provide support to the contact spring arm. U.S. Pat. No. 7,059,921 pertains to a single-piece receptacle terminal that comprises contact tines or blades that extend forward from the rear ceiling of the contact area. The tines first twist so they run parallel to the sidewalls such that the sidewalls assist in protecting the contact tines. The terminals have locking tabs and locking surfaces to lock the terminal in the housing. The contact tines also have guide shields protecting the distal end of the contact tines. U.S. Pat. No. 7,217,161 relates to female terminals comprising a main member or frame and a separate spring member. The contact section of the main member has a general box shape with side holes that have shelves for receiving lateral sides of the spring contact member. The contact section also has a downward projection, which forms an overstress protection feature for the spring contact member. 
     Further prior art includes the following. U.S. Pat. No. 7,223,134 pertains to single-piece contact with a rear zone that connects to an electrical conductor. On the front of the contact is a protective cage with a contact terminal having at least two elastic contact blades that mate with a male terminal. U.S. Pat. No. 7,241,190 relates to box-shaped tubular female terminals comprising a section for connecting to a conducting wire and a section for mating with a male terminal. A contact-spring is disposed within the contact section and the contact-spring is protected from damage by prohibiting access to the leading edge of the contact-spring. The insertion portion of the mating section has a smaller diameter than the remaining portion of the mating section. The leading edge of the contact-spring is positioned above the smaller diameter walls of the insertion portion for protection. U.S. Pat. No. 7,351,122 pertains to a receptacle terminal comprising a contact beam with spring protection members. The contact section is formed with a metal plate having opposing first and second contacts that extend at right angles to each other and thus form an L-shaped cross-section. Both contact-springs apply pressure to a mating terminal to ensure contact pressure between the receptacle terminal and the mating terminal. Japanese Patent Publication No. 2000-231956 relates to a female terminal electrical connector having a wire connecting end and a contact end. This contact is formed from a single metal plate and has an orientation feature for inserting the connector into a housing. 
     With the present approach, it has been determined that various characteristics of prior art, such as these references, have shortcomings and undesirable attributes, results or effects. The present approach recognizes and addresses matters such as these to provide enhancements not heretofore available. Overall, the present approach provides more fully enhanced miniature contact springs that fall into a so-called miniature category and that provide increased contact force. 
     More specifically, goals that have been arrived at in accordance with the present approach, while maintaining good manufacturing control and minimizing variation of tolerance, include increasing the contact engagement or holding force of a contact spring. Other goals include protecting the contact spring from damage in its operating environment, protecting the contact spring and the contact pin from damage during insertion of a male contact pin, providing overstress protection for the contact spring, improving material efficiency and polarizing the receptacle terminal for mounting. 
     SUMMARY OF THE INVENTION 
     An embodiment of the present approach generally pertains to a mating section of a miniature receptacle terminal. The mating section of this embodiment has two primary contact beams and a single secondary beam augmenting the primary contact beams. The secondary beam is angled slightly more from the receptacle wall than is at least one of the primary contact beams such that the secondary beam contacts the primary contact beam in the unmated position. Each contact beam has a contact point opposing a contact bump on the opposing wall of the receptacle terminal. A distributed and balanced contact force is exerted on a male terminal pin that is inserted between the primary contact beams and the contact bumps. The dual contact beam component permits good manufacturing control and minimizes contact force variation among individual miniature receptacle terminals made according to this embodiment. 
     In another aspect of an embodiment of the miniature receptacle terminal, the dual contact beam spring contacts are secured from the rear of the mating section improving material efficiency. High terminal performance is obtained with low manufacturing cost. 
     In an additional aspect of an embodiment of the miniature receptacle terminal, the dual contact beam spring contacts are secured within a box shaped mating section protecting the spring contacts from damage that can be caused by the operating environment. 
     In a further embodiment or aspect of the miniature receptacle terminal, the mating section has an orientation member, a terminal front stop and primary and secondary lock up surfaces that assist in mounting the miniature terminal within a connector housing. The miniature receptacle terminal can be further secured by a terminal position assurance (“TPA”) member that can interact with a side of the receptacle terminal or with an end or front of the receptacle terminal. The orientation member can have a depression protecting the primary contact beams from overstress. Also, the miniature receptacle terminal can have a guide shield to assist in mating and to protect the mating pin from damage during insertion. 
     In an additional aspect of embodiments of the miniature receptacle terminal, a support bump provides support to the primary contact beams and secondary beam. 
     Another embodiment or aspect of the miniature receptacle terminal has preload members that are in contact with primary contact beam or beams to provide a biasing force on the primary contact beams in the unmated position. 
     In another embodiment or aspect of the miniature receptacle terminal, a gap is located between the closest point of proximity of the primary and secondary contact beams in the unmated position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a miniature terminal receptacle according to the present approach; 
         FIG. 2  is a side elevation view of the miniature terminal receptacle shown in  FIG. 1 ; 
         FIG. 3  is an opposite side elevation view of the miniature terminal receptacle shown in  FIG. 1 ; 
         FIG. 4  is a front elevation view of the miniature terminal receptacle shown in  FIG. 1 ; 
         FIG. 5  is a rear elevation view of the miniature terminal receptacle shown in  FIG. 1 ; 
         FIG. 6  is a partially cut away side elevation view of the miniature terminal receptacle shown in  FIG. 1  in the unmated position; 
         FIG. 6A  is a partially cut away side elevation view of another embodiment of a miniature terminal receptacle; 
         FIG. 6B  is a front elevation view of the miniature terminal receptacle showing a variation of the receptacle shown in  FIG. 6 ; 
         FIG. 6C  is a front elevation view of another embodiment showing a variation of the miniature terminal receptacle shown in  FIG. 6 ; 
         FIG. 7  is a partially cut away side elevation view of the miniature terminal receptacle shown in  FIG. 1  in the mated position, shown with a pin inserted therein; 
         FIG. 8  is a partially cut away side elevation view of another embodiment of a miniature terminal receptacle that has a preloaded feature, shown in the unmated position; 
         FIG. 9  is a partially cut away side elevation view of the miniature terminal receptacle shown in  FIG. 8  in the mated position, shown with a pin inserted therein; 
         FIG. 10  is a partially cut away perspective view of a further embodiment of a miniature terminal receptacle; 
         FIG. 11  is a partially cut away perspective view of another embodiment of a miniature terminal receptacle; 
         FIG. 12  is a partially cut away perspective view of the miniature terminal receptacle of  FIG. 1  inserted into a connector housing; 
         FIG. 13  is a partially cut away side elevation view of another embodiment of a miniature terminal receptacle inserted into a connector housing; and 
         FIG. 14  is a partially cut away side elevation view of another embodiment of a miniature terminal receptacle inserted into a connector housing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriate manner, including employing various features disclosed herein in combinations that might not be explicitly disclosed herein. 
     In an embodiment of this approach as shown in  FIG. 1  through  FIG. 7 , miniature receptacle terminals, generally shown as  20 , have a connection section  30  for connection to a conductor such as a wire conductor (not shown) and an opposing box-shaped mating section  40  for mating with a complementary male terminal ( FIG. 7 ). Connection section  30  has sidewalls  32  for securely engaging, such as by crimping, to a conductor such as the conductor of an insulated wire. The connection section can have individual arms  34  which can wrap around the insulation of the insulated wire, for example. 
     Terminal  20  has a length (L 1 ) suitable for a miniature receptacle terminal that can be, for example, between about 17 mm and about 23 mm, suitably between about 18 mm and about 20 mm. Mating section  40  has a body portion, generally shown as  42 . Body portion  42  has length (L 2 ) which can be, for instance, between about 6 mm and about 12 mm, suitably between about 7 mm and about 10 mm. Body portion  42  also has width (W 1 ) that can be, for example, between about 3 mm and about 5 mm, typically between about 3.5 mm and about 4.5 mm. Body portion  42 , in addition, has height (H 1 ) that can be, for instance, between about 1 mm and about 5 mm, usually between about 2 mm and about 4 mm. 
     In the illustrated embodiment shown in  FIG. 6 , unmated miniature receptacle terminal  20  has at least one primary contact beam  50 , typically two primary contact beams  50  positioned in parallel within body portion  42 . By in effect splitting primary beam in two (or more) narrower beams, insertion force can be reduced when suitable while maintaining advantageous mechanical advantage and angular relationships of the overall beam structure. Primary contact beam or beams  50  are cantilevered from a first location on a support platform  44 . Primary beam or beams  50  extend from a longitudinal insertion axis  38  at an angle “b 1 .” A secondary beam  60  is positioned above primary contact beam or beams  50 . Secondary beam  60  is cantilevered from a second location on support platform  44 , which can be formed by folding a metal blank to provide a first location  45  from which the primary beam extends and a second location  47  from which the secondary beam extends. Secondary beam  60  extends from longitudinal insertion axis  38  at an angle “a 1 .” 
     In this embodiment, angle “a 1 ” is larger than angle “b 1 ” wherein a portion of secondary beam  60  makes contact with primary contact beam  50  in the unmated position. In a typical example, angle “a 1 ” is between about 5 degrees and 30 degrees, while angle “b 1 ” is between about 1 degree and 25 degrees. As shown, the respective end portions of the respective beams  50  and  60  are spaced apart from each other where these end portions connect to the support platform  44  by a selected distance  62 , while their respective free end portions engage each other. It will be noted the selected distance  62  corresponds to the spacing between first location  45  and second location  47  and defines the space or gap between the respective cantilever locations for the beams  50  and  60 . 
     As shown in  FIG. 7 , contact beams  50  further have a contact surface  52  that engages a male pin  65  when mated within the receptacle terminal. Each contact beam  50  has an upwardly extending tip portion  54  to aid in guiding male pin  65  during insertion and to protect the pin and contact beams  50  from damage. When it is desired to provide overstress protection, upwardly extending tip portion  54  can engage the interior surface of top wall  51  when male pin  65  is inserted, thereby preventing contact beam  50  and top beam  60  from overextending in the upward direction. This engagement between the interior surface and the tip portion can also help provide good contact force by stopping movement of the edge of the tip portion  54  while the curve adjacent thereto on the primary contact beam can provide flexure and bias against the inserted pin  65 . 
     In the non-preloaded embodiment shown in  FIGS. 6 and 7 , the body portion also has a protective flap  56  to further aid in guiding male pin  65  during insertion and to protect the pin and contact beam  50  from damage. In this illustrated embodiment, protective flap  56  is be sized and shaped to provide a gap  55  between upwardly extending tip  54  and protective flap  56  in the unmated position ( FIG. 6 ) so that the tip portion  54  and flap  56  do not engage each other in normal operation. 
     In the illustrated embodiment, body portion  42  further includes a wall  48 , considered a bottom wall, with one or more raised or inwardly extending bumps  46 A to aid in guiding male pin  65  and to bias the mating pin upwards. As male pin  65  is inserted into mating section  40 , male pin  65  is moved towards contact surfaces  52  by one or more bumps  46 . The height of each bump can be varied as desired as shown in  FIGS. 6B and 6C  for example. Varying the height of the bump can allow the force on contact beams  50  to be kept within a specific range while varying the thickness of male pin  65  for example. A lower height of each bump  46 B could be used when a thicker male pin  65  is used for example ( FIG. 6B ). A higher height of bump  46 C could be used when a thinner male pin  65  is used for example ( FIG. 6C ). Alternatively, bottom wall  48  can be without any inwardly extending bumps as shown in  FIG. 6A . 
     As noted in  FIG. 7 , when male pin  65  is further inserted into mating section  40 , male pin  65  engages contact surfaces  52  that are urged to move in a direction considered upward. In the fully mated position, secondary beam  60  extends from support platform  44  at an angle “a 2 ” and each primary contact beam  50  extends away from support platform  44  at an angle “b 2 ,” wherein angle “a 2 ” is larger than angle “b 2 .” In a typical example, angle “a 2 ” is between about 1 degree and 20 degrees, while angle “b 2 ” is between about 0 degrees and 15 degrees. Due to the features of the primary contact beam  50  and secondary beam  60  as generally discussed herein, the upward movement of primary contact beam  50  is resisted such that the contact engagement or holding force on the pin increases to levels similar to the pin contact engagement or holding force of larger conventional receptacle terminals that require more bulk to provide a contact engagement or holding force of this magnitude. 
     In the illustrated embodiment, bottom wall  48  has a primary lock up surface  72  that can be used to secure the miniature receptacle terminal  20  to a connector housing  80  for example of a type shown in  FIG. 12 . Top wall  51  has a polarizing projection  70  for proper mounting of receptacle terminal  20  in a connector housing or panel as shown in  FIGS. 13 and 14 . Polarizing projection  70  extends upward from only a portion of top wall  51 . A connector housing may be sized and shaped such that polarizing projection  70  can only be inserted into the connector housing in one particular orientation, thereby ensuring that the miniature receptacle terminal  20  cannot be inserted incorrectly. Top wall  51  also has one or more secondary lock up surfaces  74  that can be used to further secure the miniature receptacle terminal  20  to a connector housing. 
     A terminal front stop  73  is located on polarizing projection  70  as shown in  FIG. 13 . Such a polarizing projection facilitates proper orientation of the receptacle terminal in a connector housing while the front stop helps to control receptacle terminal insertion. A terminal front stop  173  could be located on top wall  51  as shown in  FIG. 14 . Either terminal front stop  73 ,  173  engages a surface of connector housing  80  as receptacle terminal  20  is fully inserted into connector housing  80 , thereby preventing receptacle terminal  20  from being inserted any further into connector housing  80 . 
       FIG. 13  further shows an embodiment of a receptacle terminal  20  with a terminal position assurance member. After receptacle terminal  20  is fully inserted into connector housing  80  and primary locking member  82  engages with primary lock up surface  72 , a terminal position assurance member, generally designated  92 , can be inserted into connector housing  80 . In the illustrated embodiment, this terminal position assurance member  92  can be considered a front or an end terminal position assurance member. The illustrated member  92  includes a projecting portion  96  and a support portion  98  that allows for securement of the terminal position assurance member  92  to the assembly while the projecting portion  96  is within open space  97  adjacent the primary locking member  82 . In this way, the terminal position assurance member  92  restricts outward movement of the primary locking member  82 . Any such movement is less than that needed to disengage the primary locking member  82 . More specifically, front terminal position assurance member  92  prevents primary locking member  82  from disengaging with primary lock up surface  72 . Thus this front terminal positioning member can be considered a blocking member having a blocking surface  99 . 
     Alternatively, as shown in  FIG. 14 , an embodiment of receptacle terminal  20  has a secondary locking member that is a terminal position assurance member, generally designated  94 , that can be considered a side terminal position assurance member having blocking surface  199 . This member  94  is inserted into an opening  198  into the connector housing  80  that is generally adjacent to the secondary lock up surface  74 . After receptacle terminal  20  is fully inserted into connector housing  80  and primary locking member  82  engages with primary lock up surface  72 , the terminal position assurance member  94  is inserted through the opening  198 . Insertion continues until the blocking surface  199  of terminal position assurance member  94  is in position to engage secondary lock up surface  74 . Typically, such engagement occurs if force is put on receptacle terminal  20  in the opposite direction of the insertion direction, thereby preventing receptacle terminal  20  from substantial movement within connector housing  80 . 
     Body portion  42  has side walls  49 . A beam support  76  ( FIGS. 1 ,  3 ,  6 ,  6 A and  7 - 11 ) projects from a housing side wall  49  to provide support to each primary contact beam  50  and the secondary beam  60 . In the illustrated embodiment, a flap support  78  ( FIGS. 1 ,  3 ,  4 ,  6 ,  6 A and  7 - 11 ) also projects from a housing side wall  49  to provide support to the protective flap  56 . A tab  58  ( FIG. 2 ) extends down from a portion of top wall  51  to prevent deformation of top wall  51  from excessive force, such as terminal nose stubbing during insertion of the receptacle terminal into a housing for example. The bottom edge  59  of tab  58  engages with housing side wall  49  as top wall  51  is biased downward. 
     In the illustrated embodiment shown in  FIG. 8 , unmated miniature receptacle terminal  120  has at least one primary contact beam  150 , typically two primary contact beams  150  positioned in parallel within body  42 . Primary contact beam or beams  150  are cantilevered from a first location on support platform  44 . Primary beam or beams  150  extend from a longitudinal insertion axis  38  at an angle “d 1 .” A secondary beam  160  is positioned above primary contact beam or beams  150 . Secondary beam  160  is cantilevered from a second location on support platform  44 . Secondary beam  160  extends from longitudinal insertion axis  38  at an angle “c 1 .” In this embodiment, angle “c 1 ” is larger than angle “d 1 ” wherein a portion of secondary beam  160  makes contact with primary contact beams  150  in the unmated position. In a typical example, angle “c 1 ” is between about 5 and 30 degrees, while angle “d 1 ” is between about 1 and 25 degrees. As shown, the respective end portions of the respective beams  150  and  160  are spaced apart from each other where these end portions connect to support platform  44  by a selected distance  62  between first and second locations  45  and  47 , while their respective free end lengths engage each other. 
     As shown in  FIG. 8 , an upwardly extending tip portion  154  is engaged with a protective flap  156  such that upwardly extending tip  154  is biased upward in a preloaded condition prior to insertion of a male pin  165  ( FIG. 9 ). Such preloading of the primary contact beam or beams  150  may reduce the insertion force required to mate with male pin  165  due to the force component of the insertion load force of the beam or beams  150  that is taken up by the flap  156  as it engages the beam tip portion  154 . 
     As shown in  FIG. 9 , contact beams  150  further have a contact surface  152  that engages male pin  165  when mating. The tip portion  154  of the contact beam  150  has an upwardly extending tip end to aid in guiding male pin  165  during insertion and to protect the pin and contact beams  150  from damage. To provide overstress protection, upwardly extending tip portion  154  can engage the interior surface of top wall  51  when male pin  165  is inserted, thereby preventing contact beams  150  and top beam  160  from overextending in the upward direction. This engagement can also improve connection integrity by providing flexure and bias against the inserted pin  165  that is generated by engagement between tip portion  154  and wall  51 . Housing  42  also has a protective flap  156  to further aid in guiding male pin  165  during insertion and to protect the pin and contact beams  150  from damage. 
     In the illustrated embodiment shown in  FIG. 10 , unmated miniature receptacle terminal  220  has at least one primary contact beam  250 , typically two primary contact beams  250  positioned in parallel within body  42 . Primary contact beam or beams  250  are cantilevered from a first location on support platform  44 . Primary beam or beams  250  extend from a longitudinal insertion axis  38  at an angle “f 1 .” A secondary beam  260  is positioned above primary contact beam or beams  250 . Secondary beam  260  is cantilevered from a second location on support platform  44 . Secondary beam  260  extends from longitudinal insertion axis  38  at an angle “e 1 .” In this embodiment, angle “e 1 ” and angle “f 1 ” are sized such that there is a beam gap  275  between secondary beam  260  and primary contact beam  250  in the unmated position. In the embodiment that is illustrated in  FIG. 10 , this gap  275  begins at the selected distance  62  and extends the full length of the secondary beam  260 . In a typical example, angle “e 1 ” is between about 1 and 30 degrees, and angle “f 1 ” is between about 1 and 30 degrees. 
     In the illustrated embodiment shown in  FIG. 11 , unmated miniature receptacle terminal  320  has at least one primary contact beam  350 , typically two primary contact beams  350  positioned in parallel within body  42 . Primary contact beam or beams  350  are cantilevered from a first location on support platform  44 . Primary beam or beams  350  extend from a longitudinal insertion axis  38  at an angle “h 1 .” A secondary beam  360  is positioned above primary contact beam or beams  350 . Secondary beam  360  is cantilevered from a second location on support platform  44 . Secondary beam  360  extends from longitudinal insertion axis  38  at an angle “g 1 .” In this embodiment, angle “g 1 ” and angle “h 1 ” are sized such that there is a beam gap  375  between secondary beam  360  and primary contact beam or beams  350  in the unmated position. An upwardly extending tip portion  354  is engaged with a protective flap  356  such that upwardly extending tip portion  354  is biased upward in a preloaded condition prior to insertion of a male pin (not shown). Such preloading of the primary contact beam or beams  350  may reduce the insertion force required to mate with a male pin (not shown) due to the force component of the insertion load force of the beam or beams  350  that is taken up by the flap  356  as it engages the beam tip portion  354 . In a typical example, angle “g 1 ” is between about 1 and 30 degrees, and angle “h 1 ” is between about 1 and 30 degrees. 
     As shown in  FIG. 12 , unmated miniature receptacle terminal  20  is inserted into a connector housing  80 . A primary locking member  82  engages with primary lock up surface  72  to hold the miniature receptacle terminal  20  in place. Other interactions between the miniature receptacle terminal  20  and the connector housing  80  also are shown. It will be appreciated that the connector housing  80  is insulative or of a dielectric material while the miniature receptacle terminal is conductive. 
     It will be understood that there are numerous modifications of the illustrated embodiments described above which will be readily apparent to one skilled in the art, such as many variations and modifications of the miniature receptacle terminals and/or its components including combinations of features disclosed herein that are individually disclosed or claimed herein, explicitly including additional combinations of such features, or alternatively other types of miniature receptacle terminals. Also, there are many possible variations in the materials and configurations. These modifications and/or combinations fall within the art to which this approach relates and are intended to be within the scope of the claims, which follow.