Electrical contact receptacle to mate with round and rectangular pins

Information

  • Patent Grant
  • 6475040
  • Patent Number
    6,475,040
  • Date Filed
    Wednesday, May 24, 2000
    24 years ago
  • Date Issued
    Tuesday, November 5, 2002
    22 years ago
Abstract
The electrical receptacle according to this invention is stamped and formed from a flat blank and has an upper wall, a first side wall extending from the upper wall,a lower wall extending from the first side wall, and a second side wall extending from the lower wall, wherein the first and second side walls are opposed, and adjacent walls are joined by radiused sections, wherein the electrical receptacle also includes a spring beam extending from the upper wall such that edges of the spring beam are spaced from adjacent side walls, and wherein each side wall includes an inwardly formed section or radiused rib to position a male terminal inserted into the electrical receptacle in alignment with the spring beam.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to electrical connectors and electrical connector female terminals that can mate with male terminals having either round or rectangular cross sections. This invention also relates to stamped and formed electrical terminals that use a spring beam that is deflected upon engagement with either the round or rectangular male terminal to generate a normal force contact.




2. Description of the Prior Art




Mating electrical terminals typically employ mating female and male terminals. In many connectors the female connector comprises a-receptacle terminals that is stamped and formed from a spring metal blank. These stamped and formed receptacle terminals typically employ a deflectable spring to establish a normal force contact with the male terminal. These springs can be in the form of cantilever beams extending from one wall of the receptacle terminals or formed beams that are joined to the terminal wall on both ends.




The male terminal can also be stamped and formed, although typically the male terminal will not be a resilient member. In many applications a solid pin is used. These solid pins or blades can have a rectangular or square cross section or they can have a round cross section. Indeed some round pins are simply sections of a round wire. Even though the diameter of the round pins is equal to the thickness of the flat pin or blade, the same receptacle terminal may not be suitable for use with both rectangular and round pins. One problem is that the round pin can shift or roll laterally relative to the spring beam, and may not always remain in contact with the flat contact section of the receptacle spring.




SUMMARY OF THE INVENTION




The electrical receptacle terminal according to the invention depicted herein can establish a normal force contact with either a first male terminal having a rectangular cross section or a second male terminal having a circular cross section. The receptacle terminal has a spring member extending from a first receptacle wall. The spring member is deflectable upon engagement with either a first male terminal or a second male terminal to generate a normal force acting upon the male terminal in engagement therewith. Ribs extend inwardly from opposed receptacle side walls to position the male contact in engagement with the spring member in alignment with the spring member.




The electrical receptacle is stamped and formed from a flat blank. The receptacle has an upper wall, a first side wall extending from the upper wall, a lower wall extending from the first side wall, and a second side wall extending from the lower wall. The first and second side walls are opposed, and adjacent walls are joined by radiused sections. The electrical receptacle also includes a spring beam extending from the upper wall. Edges of the spring beam are spaced from adjacent side walls. Each side wall includes an inwardly formed section to position a male terminal inserted into the electrical receptacle in alignment with the spring beam.




The electrical receptacle terminal comprises a female terminal that can be used in an electrical connector assembly to mate with a round pin. The receptacle terminal includes a cantilever spring beam with a contact area on the cantilever spring beam in engagement with the round pin. The receptacle terminal includes walls extending beside the cantilever spring beam with sections protruding inwardly from the walls. the axial centerline of the round pin is kept in alignment with the contact area on the cantilever spring beams by these inwardly protruding sections











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

shows a plan view of an electrical contact;





FIG. 2

shows a side view of an electrical contact;





FIG. 3

shows a view of the front end of the electrical contact;





FIG. 4

shows a view from below of the electrical contact;





FIG. 5

shows a second side view of the electrical contact;





FIG. 6

shows a section through the conductor crimp;





FIG. 7

shows a section through the insulation crimp;





FIG. 8

shows a section along the section line BB according to

FIG. 3

;





FIG. 9

shows a section along the section line AA according to

FIG. 8

;





FIG. 10

shows a plan view of the layout of a contact which has been stamped out but not yet folded;





FIG. 11

shows a longitudinal section through a slightly modified contact;





FIG. 12

shows a layout of the slightly modified contact;





FIG. 13

shows a view of the plug-in face end of a housing;





FIG. 14

shows a section along the section line BB according to

FIG. 13

;





FIG. 15

shows a section along the section line AA according to

FIG. 13

;





FIG. 16

shows a view of a housing from the cable end;





FIG. 17

shows a section along the section line CC according to

FIG. 13

; and





FIG. 18

shows a detailed view of the detail X according to FIG.


15


.





FIG. 19

is a side view of an alternate embodiment of the receptacle terminal.





FIG. 20

is a view of the side opposite that shown in

FIG. 19

of the alternate embodiment of the receptacle terminal.





FIG. 21

is a section view of the mating portion of the alternate embodiment of the receptacle terminal shown in

FIGS. 19 and 20

.





FIG. 22

is a cross section taken along section lines


22


in

FIG. 21

of the mating portion of the alternate embodiment of the receptacle terminal.





FIG. 23

is a cross section view showing the alternate receptacle terminal in engagement with a round pin.





FIG. 24

is a cross section view showing the alternate receptacle terminal in engagement with a rectangular pin with a thickness equal to the diameter of the round pin shown in FIG.


23


.





FIG. 25

is a cross section view showing the alternate receptacle terminal in engagement with a square pin with a thickness equal to the diameter of the round pin shown in FIG.


23


.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS





FIGS. 1-18

depict an electrical connector and a contact that is suitable for use in making contact with a square or rectangular pin or blade terminal. The instant invention shown in the remainder of the views shows an electrical receptacle contact that can be substituted for the receptacle contact shown in

FIGS. 1-18

that will make a reliable electrical contact with a round pin having the same diameter as the thickness of the square or rectangular pin with which the embodiment of

FIGS. 1-18

is used. The embodiment of

FIGS. 19-25

will also make a reliable contact with a square or rectangular pin in addition to contacting the round pin. Since the receptacle contact shown in

FIGS. 19-25

is substitutable for the contact shown in

FIGS. 1-18

, a complete description of that contact and the connector with which it is used is included herein. The connector and contact disclosed in

FIGS. 1-18

is also disclosed in U.S. patent application Ser. No. 09/077,814 filed Jun. 4, 1998, which is incorporated herein by reference. The receptacle contact terminal


102


of the alternate embodiment of

FIGS. 19-25

can be substituted for the female terminals of

FIGS. 1-12

in the housing shown in

FIGS. 13-18

. The receptacle contact terminals


102


can also be mounted in housings such as that shown in U.S. Pat. No. 6,100,340, which is incorporated herein by reference.





FIG. 1

illustrates a plan view of a contact


1


according to the invention. The contact comprises a conductor connection region


2


and a contact-making region


3


. The conductor connection region


2


serves for connection to an electrical conductor wire and has two crimp regions, an insulation crimp


21


and a crimp


22


for the electrical conductor wire. The contact-making region


3


serves to make contact with a complementary contact pin, the contact pin being introduced into the contact-making region from the front end of the latter. As can be seen particularly clearly in

FIG. 3

, which illustrates a view from the front end of the contact, the contact-making region is essentially designed in the form of a box. This box is not rectangular but rather trapezoidal in its cross-section. As can be seen in

FIG. 3

, the contact-making region


3


has two side walls


4


and


5


, a top wall


6


and a bottom wall


7


. The bottom wall


7


is in this case designed to be narrower than the top wall


6


, thereby achieving the trapezoidal appearance. The two side walls


4


and


5


are therefore arranged such that they are inclined with respect to the top wall and with respect to the bottom wall


7


, and they also run in a manner inclined with respect to one another.





FIG. 1

provides a view of the top wall


6


, it also being possible to see the side walls


4


and


5


.

FIG. 2

shows a view of the side wall


5


, and

FIG. 5

shows a view of the side wall


4


. In both illustrations, the contact spring arm


8


is illustrated by dashed lines. The contact spring has a free end at the front end of the electrical contact I and is connected to the top wall


6


in the direction of the conductor connection region


2


. As is evident from

FIG. 2

, the top wall comprises two layers


61


and


62


in the region near to the conductor connection region


2


. The supporting spring arm


9


, which is both shown by dashed lines in the illustrations


2


and


5


and can also be seen in

FIG. 1

, is bent away from the upper layer


61


. The supporting spring


9


supports the contact spring arm


8


, which starts out from the lower layer


62


of the top wall


6


. Furthermore, the compensating leaf spring


10


can be seen in the figures. This is a spring which is cut free at one end and extends away from the conductor connection region. The spring is bent inwards, and two stops


11


and


12


(see

FIG. 4

) start out from the bottom wall


7


and prevent the spring from overstretching.

FIGS. 6 and 7

illustrate the sections along the section lines B and D through the two crimp regions. A lug


13


extends forwards from the top wall


6


and is bent inwards into the contact-making region


3


. This lug serves as an insertion funnel for the insertion of a complementary contact pin or contact blade.





FIG. 8

illustrates a section through the electrical contact


1


along the section line BB according to FIG.


3


. The top wall


6


with the two layers


61


and


62


can be seen particularly clearly in this illustration. The arrangement of contact spring arm


8


and supporting spring arm


9


, as well as compensating leaf spring


10


and stop


12


, also becomes clear here. In the exemplary embodiment illustrated, the contact spring arm


8


is not prestressed, that is to say the lug


13


serves exclusively for forming an insertion funnel. However, it is possible to achieve prestressing of the contact spring arm


8


. The lug


13


then likewise serves as a stop for the prestressed contact spring arm


8


. The section illustrated also shows the opening


25


, in which a latching means (illustrated by dashed lines) can engage in order to hold the contact in a chamber.




The cross-sectionally trapezoidal contact-making region can be seen clearly once again in

FIG. 9

, which illustrates a section along the line AA through FIG.


8


. The side walls


4


and


5


run in a manner inclined with respect to one another. The compensating leaf spring


10


is situated above the stops


11


and


12


inside the contact-making region. The contact spring arm


8


is supported by the supporting spring arm


9


. The contact spring arm


8


is bent in the contact-making region, as illustrated in FIG.


9


. This bending extends over the entire length of the contact spring arm


8


in order to increase the stiffness.




The layout of the contact according to the invention can be seen clearly in FIG.


10


. The contact-making region


3


is formed by folding a number of times, the top wall being formed from two layers


61


and


62


. The contact spring arm


8


is formed from the layer


62


, while the supporting spring arm


9


and the lug


13


are formed from the layer


61


. The stops


11


and


12


as well as the compensating leaf spring


10


are formed from the bottom wall


7


. An opening


23


and a corresponding lug


24


, which secures the lower layer of the wall


61


to the side wall, can be seen from the layout. The cross-hatched regions on the contact spring arm


8


and the compensating leaf spring


10


represent those regions of the contact which are gold-plated for the purpose of better contact-making.





FIG. 11

illustrates a longitudinal section (as in

FIG. 8

) through a further version of a contact and

FIG. 12

illustrates a corresponding layout. These differ from the contact illustrated in

FIGS. 8 and 10

in terms of the different compensating spring. The compensating leaf spring


100


illustrated is joined at both ends and cut free only on the sides. Its deflection is thereby limited and stops are not provided.





FIGS. 13

to


18


then illustrate a housing which is suitable for accommodating a contact according to the invention. The housing


14


has four contact chambers


17


to


20


. The contact chambers each extend from the cable end of the housing


14


as far as the plug-in face end of the housing, where openings are provided for the introduction of complementary contact pins.




As emerges particularly clearly from

FIG. 16

, the view from the cable end of the housing, the chamber walls between the individual chambers


17


to


20


are very thin. As a result of the inventive form of the contacts, namely their trapezoidal cross-section, it is possible for the width of the chamber walls to change over the layer thereof and, as a result, for a robust region to be produced at least on one side. This enables the contacts, or the contact chambers, to be arranged as close to one another as possible.




From

FIG. 15

, it is evident that each contact chamber is assigned a flexible arm


15


having a latching lug


16


which engages in the contact chamber. When the contact is introduced, the latching lug


16


enters an opening


25


in the top wall


6


of the contact (see

FIG. 1

or


8


) and secures the contact in the chamber.




The flexible arm


15


is illustrated once again, in detail, in FIG.


18


. It can be seen here that the end face


26


of the flexible arm is bevelled. This bevelling serves the following purpose: if a contact is introduced incompletely into the contact chamber, the flexible contact arm


15


is bent outwards, that is to say out of the contact chamber. If an attempt is made in this state to connect a complementary connector to the illustrated connector, then a wall region of the complementary connector, which normally engages in the depression


27


(see FIG.


18


), runs up against the oblique end face


26


of the flexible arm. The special configuration of the end face prevents the flexible arm from being pressed back into its original position by the wall region of the complementary connector even though the contact is incorrectly introduced. What is effected by this is that the flexible arm


15


is moved even further out of the chamber.




The alternate embodiment of the receptacle contact terminal


102


shown in

FIGS. 19-25

is stamped and formed from a flat blank. The contours or the edges of the contact receptacle structures are first stamped in the flat blank of spring metal, such as a copper alloy. The flat stamped blank is then formed along bend lines to form the final structure. Receptacle terminal


102


has a mating or contact section


104


that has a box shape having walls that will surround a male terminal, such as a pin or blade, when inserted into contact section


104


. In the alternate embodiment, the cross section of the contact section


104


has a substantially trapezoidal shape of the type illustrated by the embodiment of

FIGS. 1-18

. The receptacle terminal


102


also includes a crimp section


106


for attaching the terminal to a wire. It should be understood that other equivalent means may be provided to attach a receptacle terminal


102


to an external conductor. For example an insulation displacement contact section or a solder section could be used. The mating section


104


, to be subsequently described in more detail, could also be used on a printed circuit board receptacle terminal. Multiple stamped and formed receptacle terminals


102


are connected by a carrier strip


108


in a conventional manner.




The receptacle terminal mating section


104


is formed by folding sections of the flat blank into a configuration having five wall sections. These wall sections are shown in

FIGS. 21 and 22

. A first upper wall section


110


is joined to a first side wall


112


by a radiused corner. The first side wall


112


is in turn joined to a lower wall


114


again with a radiused intermediate corner between the two adjacent wall sections. A second side wall


116


extends from the opposite radiused corner of the lower wall


114


. The first side wall


112


is opposed to the second side wall


116


, although the two side walls are mutually inclined in the trapezoidal mating section


104


. The fifth wall


118


of the mating section


104


is joined to the second side wall


116


and is formed over the upper wall


110


so that this end wall section overlaps the upper wall


110


.




A mating normal force contact is formed between the receptacle terminal


102


and a mating male terminal, or pin or blade, and is established by a spring beam


124


located in the contact mating section


104


. In receptacle terminal


102


, this spring beam


124


comprises a cantilever spring beam


124


which extends from the inner top wall


110


as best seen in FIG.


21


. This tapered cantilever beam


124


has a wider base than tip resulting in generation of more contact force. A contact area, which is the closest portion of the beam


124


to the lower wall


114


, is located adjacent to the narrower tip of the cantilever beam


124


. As shown in

FIG. 21

the end of the cantilever beam


124


engages a tab section at the front of the mating section


104


to preload the cantilever beam


124


in the same manner as for the embodiment of

FIGS. 1-18

. A helper spring


126


is formed from the overlapping top wall


118


and is positioned behind the main cantilever contact spring


124


as a back up. This helper spring


126


will increase the normal force contact established between the contact spring


124


and the male terminal inserted into mating section


104


. Although the helper spring


126


is an effective means to increase the contact force, in some applications of this invention, such as where a noble metal plating is used, the helper spring


126


may be omitted. It should also be understood that in other embodiments, the spring beam


124


need not be a cantilever spring and could be joined at both ends to the wall from which the beam extends.




A tab


136


is struck inwardly from the side wall


116


adjacent the rear of the mating section


104


. As seen in

FIG. 21 and 22

, this inwardly struck tab


136


supports a free edge of the inner top wall


110


, from which the cantilever contacts beam


124


extends. Tab


136


has a chamfered upper edge


138


which engages a curved lower surface of the inner top wall


110


when the wall


110


is formed over into engagement with the tab


136


. This tab


136


function to precisely position the wall


110


and to prevent the cantilever beam


124


from being tilted relative to a plane extending parallel to the lower wall


114


. The cantilever spring beam


124


, which can also be supported at its free end by the lip forming the entrance to the mating section


104


, will thus be properly oriented relative to either a round or rectangular male pin inserted into the receptacle mating section


104


. The cantilever beam


124


thus will not be canted relative to a mating male terminal. If the cantilever beam


124


is canted or tilted relative to the mating male terminal, the contact area between the two terminals will be smaller, resulting in a higher localized contact force, and excessive wear at the mating interface.




The mating section


104


also has a lower support surface


128


formed upward from the lower wall


114


. When a male terminal is inserted into the mating section


104


, contact will be established with the male terminal by both the contact area on the main cantilever spring


124


and the lower support surface


128


and the male terminal will be aligned between these two contact surfaces.




The width of the lower wall


114


is less then the width of the upper wall


110


so that the two side walls


112


and


116


are inclined and converge with increasing distance form the upper wall


110


. Each side wall also has an inwardly extending section formed adjacent the lower wall


114


. Inwardly extending rib


120


is formed in side wall


112


, and rib


122


is formed in side wall


116


. Each of these ribs


120


,


122


extends from the front of the mating section


104


to its rear. These ribs


120


,


122


will thus have a length that is sufficient to extend along substantially the entire length of a mating male terminal inserted into the mating section


104


. The ribs


120


,


122


are radiused inwardly and are formed by punching the initially flat side wall section. In this embodiment, the ribs


120


,


122


are joined to the corresponding side wall along both the upper and lower edges, although as shown in

FIGS. 23-25

, this rib can be separated from the corresponding side wall along either the top or bottom edge of the rib. Ribs


120


,


122


are formed in a position such that the ribs will be aligned with the sides of a male terminal inserted into the mating section


104


between the contact area of the cantilever spring beam


124


and the lower support surface


128


.




The inwardly formed and radiused ribs


120


and


122


function to permit the receptacle terminal


102


with a cantilever beam spring


124


to be used with a round pin in addition to a rectangular or square pin or with a blade.

FIG. 23

shows the use of receptacle terminal


102


having inwardly formed and radiused ribs


120


,


122


with a round pin


130


. Note that the edges of the cantilever beam spring


124


are spaced from the side walls


112


and


116


. This spacing is due to practical consideration inherent in a stamped and formed contact. First, the bend line between oblique walls must be radiused to prevent fracturing or stress concentrations. Second, there must be sufficient material between the base of the beam and the edges of the wall


112


from which it is formed to withstand sufficient stress to generate a normal force contact between the cantilever beam


124


and the round contact pin


130


. However, a round contact pin


130


could move laterally when contact by the spring


124


into, or at least partially into, the gap between either side wall


112


or


116


. Lateral movement of the round pin out of alignment with the spring beam


124


can result in a defective contact and lower normal force applied at the contact area to the round pin


130


. The inwardly radiused ribs


120


and


122


function to prevent excessive lateral movement of the round pin


130


out of alignment with the contact area of the spring beam


124


and the lower support surface


128


. Since the radiused ribs


120


,


122


extend over substantially the entire length of the mating section


104


they can engage a male terminal, such as round pin


130


substantially over the entire portion of that pin, which extends into the mating section


104


. Note that in

FIG. 23

, the axial centerline of the round pin


130


remains beneath the flat contact areas on the spring beam


124


and the support surface


128


, even when the lateral offset of the round pin


130


is at its greatest.

FIGS. 24 and 25

show the use of the same receptacle contact


102


with rectangular pins


132


or with square pins


134


that have a thickness that is equal to the diameter of the round pin


130


. In the examples shown herein the round pin


130


has a diameter of 0.64 mm. and the thickness of the rectangular pins


132


and square pins


134


is also 0.64 mm., a standard dimension for terminals of this type. Of course the same approach could be use with male and female terminals having different dimensions.




It should be understood that the embodiment depicted herein comprises a representative embodiment of this invention. One of ordinary skill in the art could of course substitute equivalent structures for the representative elements depicted herein. For example, the raduised ribs


120


,


122


could be replaced by a series of embossments or dimples that would engage a round pin at multiple axial locations, and this modification would still function to achieve the same functions of preventing the round pin from shifting laterally out of engagement with the box receptacle contact surfaces. Therefore the invention is to be defined by the following claims and not by the representative embodiment depicted herein.



Claims
  • 1. An electrical receptacle terminal comprising:a) a crimp section structured to receive and crimp a wire conductor therein; b) a receptacle section positioned immediately forward of and adjacent to said crimping section, the receptacle section having a cavity therein structured to receive male terminals having a rectangular cross-section and male terminals having a circular cross-section; c) said cavity defined by a bottom wall, a top wall, and a pair of opposing side walls, said side walls being connected to both said top and bottom walls,said top wall having a spring member extending therefrom, said spring member being deflectable upon engagement with a male terminal to generate a normal force acting upon the male terminal in engagement therewith, regardless of whether the male terminal has a circular cross-section configuration or a rectangular cross-section configuration; d) each said side wall of said receptacle section having a fixed linearrib member oriented along a longitudinal axis of the receptacle section, and extending substantially the entire length of said cavity, said rib members projecting inwardly from said side walls toward an interior of said receptacle section to position a male terminal in alignment with and in engagement with the spring member and to support the male terminal along substantially all of that portion of the male terminal received within the cavity of the receptacle terminal.
  • 2. The electrical receptacle terminal of claim 1 wherein the opposed side walls extend transverse to the first receptacle wall.
  • 3. The electrical receptacle terminal of claim 1 wherein the opposed side walls and the first receptacle wall comprise folded sections of an initially flat blank.
  • 4. The electrical receptacle terminal of claim 3 wherein only one of the opposed side walls is joined directly to the first receptacle wall.
  • 5. The electrical receptacle terminal of claim 4 wherein a second side wall extends from an overlapping receptacle wall that extends over the first receptacle wall.
  • 6. The electrical receptacle terminal of claim 1 wherein the inwardly extending ribs comprise arcuately formed sections of the opposed side walls.
  • 7. The electrical receptacle terminal of claim 6 wherein the ribs are joined to the side wall from which each extends, both above and below the rib.
  • 8. The electrical receptacle terminal of claim 6 wherein one edge of each rib is separated from the side wall from which the rib extends.
  • 9. The electrical receptacle terminal of claim 1 having a trapezoidal cross section in which the opposed side walls converge with distance from the first receptacle wall and the spring member is a tapered member.
CROSS REFERENCE TO CO-PENDING PROVISIONAL PATENT APPLICATION

This Application claims the benefit of Provisional Patent Application Ser. No. 60/136,719 filed on May 28, 1999.

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Entry
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Provisional Applications (1)
Number Date Country
60/136719 May 1999 US