Electrical connector with overtwisted wire pairs

Information

  • Patent Grant
  • 6568953
  • Patent Number
    6,568,953
  • Date Filed
    Thursday, January 31, 2002
    23 years ago
  • Date Issued
    Tuesday, May 27, 2003
    21 years ago
Abstract
An electrical connector includes a dielectric body having an input end and an output end opposite the input end. First and second electrical contacts are located at the output end. A twisted wire pair is connected to the first and second electrical contacts, defines an axial length, includes first and second wires twisted along the axial length, and has first and second terminal ends. The first and second terminal ends are connected to the first and second electrical contacts and include first and second portions. The first portion is located axially between the second portion and first and second terminal ends of the first and second wires. The first portion has a first degree of twist about a longitudinal axis of the twisted wire pair. The second portion has a second degree of twist about the longitudinal axis of the twisted wire pair. The first degree of twist is substantially greater than the second degree of twist.
Description




FIELD OF THE INVENTION




The present invention relates to an electrical connector that meets high performance standards particularly in high speed data transmissions. More specifically, the present invention relates to an electrical connector, such as a telecommunications plug, receivable in a another mating connector, such as a telecommunications jack, that includes overtwisted wire pairs in the connector to reduce crosstalk, thereby increasing performance to meet high performance standards, such as in category 6 applications.




BACKGROUND OF THE INVENTION




Advancements in telecommunications require high speed data transmission. In order to meet performance standards for high speed data transmission, such as category 6 performance standards, crosstalk must be reduced. Conventional electrical connectors, such as telecommunication plugs and jacks, produce unacceptable levels of crosstalk due to interfering signals from the wires of the connectors, thereby degrading the performance of the connector. In particular, conventional plugs, such as the industry standard RJ45 plug, terminate cables typically having eight wires that are close together and parallel leading to excessive crosstalk.




A conventional solution to this crosstalk problem is to twist each pair of wires. Specifically, when wires of a pair are twisted their equal and opposite signals cancel each other resulting in a reduction of crosstalk between the wires. However, this solution is often inadequate for high speed data transmissions, particularly due the need to untwist or separate the wires in order to connect them to pins corresponding to their terminal assignments. Specifically, the distance from where the wires are separated to the pins significantly contributes to crosstalk. Additionally, air or space between individual wires of a wire pair also affects impedance which can increases return loss or signal reflection as the signals travel through the connector, thereby decreasing performance.




Another solution to the problem of crosstalk, is to provide a dielectric insert or block where the wires are separated in the connector, thereby fixing the positions of each wire pair and reducing crosstalk by isolating the signals of the wires from each other. Although this solution reduces crosstalk, incorporation of such inserts is cost prohibitive.




Examples of conventional telecommunications electrical connectors include U.S. Pat. No. 6,007,368 to Lorenz et al; U.S. Pat. No. 5,350,324 to Guilbert; U.S. Pat. No. 5,911,594 to Baker, III et al.; U.S. Pat. No. 6,176,732 to Schultz et al.; and U.S. Pat. No. 5,226,835 to Baker, III, the subject matter of each of which is herein incorporated by reference.




SUMMARY OF THE INVENTION




Accordingly, an object of the present invention is to provide an electrical connector that reduces crosstalk and improves performance, particularly in category 6 applications.




Another object of the present invention is to provide an electrical connector that is inexpensive to manufacture and also meets performance standards for high speed data transmissions.




Yet another object of the present invention is to provide an electrical connector that includes overtwisted wire pairs to reduce crosstalk and also increase the stability of the wire pairs.




The foregoing objects are basically attained by an electrical connector including a dielectric body that has an input end and an output end opposite the input end. First and second electrical contacts are located at the output end. A twisted wire pair is connected to the first and second electrical contacts. The twisted wire pair defines an axial length includes first and second wires twisted along the axial length, and has first and second terminal ends, respectively. The first and second terminal ends are connected to the first and second electrical contacts, respectively, and include first and second portions. The first portion is located axially between the second portion and first and second terminal ends of the first and second wires. The first portion having a first degree of twist about a longitudinal axis of the twisted wire pair. The second portion has a second degree of twist about the longitudinal axis of the twisted wire pair. The first degree of twist is substantially greater than the second degree of twist.




The foregoing objects are also attained by a method of terminating wires to an electrical connector, comprising the step of twisting together first and second wires to a form a first twisted wire pair having an axial length and first and second portions,. The first portion is located axially between the second portion and the terminal ends of the first and second wires. The method also includes the step of overtwisting the first portion of the first twisted wire pair about the axial length so that the degree of twist about the axial length at the first portion is substantially greater that the degree of twist about the axial length at the second portion. Also, the method includes the step of connecting the first and second terminal ends of the first and second wires, respectively, to first and second electrical contacts, respectively, of the electrical connector.




By forming the electrical connector in the above manner, crosstalk is reduce and performance is enhanced to meet the requirements of high speed data transmissions without the use of an insert.




Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with annexed drawings, discloses a preferred embodiment of the present invention.











BRIEF DESCRIPTION OF THE DRAWINGS




Referring to the drawings which form a part of this disclosure:





FIG. 1

is a partial perspective view of an electrical connector in accordance with an embodiment of the present invention, showing a wire connected to an electrical contact of the connector; and





FIG. 2

is a diagrammatic top plan view of the electrical connector illustrated in

FIG. 1

, showing the overtwisted wire pairs connected to their respective terminal assignments.











DETAILED DESCRIPTION OF THE INVENTION




Referring to

FIGS. 1 and 2

, an electrical connector


10


in accordance with an embodiment of the present invention generally includes a dielectric body


12


that receives a cable


14


having first, second, third, and fourth twisted wires pairs


16


,


18


,


20


and


22


. First, second, third, and fourth twisted wires pairs


16


,


18


,


20


and


22


are overtwisted to reduce crosstalk and improve performance required for high speed telecommunications data transmission, such as for category 6 applications. Electrical connector


10


is preferably a telecommunications plug that is connectable to a mating connector (not shown), such as a category 6 jack.




As seen in

FIG. 1

, the structure of electrical connector


10


is that of a conventional RJ45 plug connector including dielectric body


12


with an input end


24


for receiving cable


14


and an output end


26


receivable in a mating connector for electrical connection therewith. Dielectric body


12


includes an inner cavity


28


for receiving and supporting cable


14


with an access opening


30


provided in input end


24


. The top wall


32


of connector


10


includes an opening


33


near input end


24


shaped to receive a strain relief member (not shown) for crimping cable


14


when received in body inner cavity


28


in a conventional manner. The bottom wall


34


of connector


10


includes a conventional spring lock tab


36


for securing connector


10


to a mating connector.




At output end


26


of connector body


12


are an array of terminal slots


38


extending from a first side wall


40


to an opposite second side wall


42


. Each slot


38


is open at its upper end


44


and receives an electrical contact


46


. As seen in

FIGS. 1 and 2

, electrical contacts


46


represent terminal positions


1


-


8


, respectively, standard in telecommunications connectors. Each electrical contact


46


is preferably a conventional metallic pin having a contact end


48


and insulation displacement end


50


opposite contact end


48


, as seen in FIG.


1


. Each contact end


48


is exposed at the upper ends


44


of terminal slots


38


for electrical connection with the contacts (not shown) of the mating connector. Each insulation displacement end


50


tears or pierces first, second, third, and fourth wire pairs


16


,


18


,


20


and


22


, respectively, for mechanically and electrical connection thereto, as is well known in the art.




As seen in

FIGS. 1 and 2

, cable


14


includes a cable body


52


supporting first, second, third, and fourth wire pairs


16


,


18


,


20


and


22


within a cable jacket


54


with the wire pairs extending through and beyond the cable open end


56


. Cable


14


extends through access opening


30


of electrical connector


10


and into connector inner cavity


28


with the cable body


52


being crimped at connector input end


24


, as is well known in the art.




Cable


14


supports first, second, third, and fourth wire pairs


16


,


18


,


20


and


22


. Each wire pair


16


,


18


,


20


and


22


includes two wires twisted around each other along a longitudinal axis. Wire pairs


16


,


18


,


20


and


22


are shown spaced from one another for illustrative purposes, however, in use these wire pairs are adjacent or overlap one another. In particular, first twisted wire pair


16


includes twisted first and second wires


60


and


62


, second wire pair


18


includes twisted third and fourth wires


64


and


66


, third wire pair includes twisted fifth and sixth wires


68


and


70


, and fourth wire pair includes twisted seventh and eight wires


72


and


74


. As seen in

FIG. 2

, first and second wires


60


and


62


are connectable to electrical contacts


46


at terminal positions


1


and


2


, respectively, by wire terminal ends


76


and


78


; third and fourth wires


64


and


66


are connectable to electrical contacts


46


at terminal positions


4


and


5


, respectively, by wire terminal ends


80


and


82


; fifth and sixth wires


68


and


70


are connectable to electrical contacts


46


at terminals positions


3


and


6


, respectively, by wire terminal ends


84


and


86


; and seventh and eighth wires


72


and


74


are connectable to electrical contacts


46


at terminal positions


7


and


8


, respectively, by wire terminal ends


88


and


90


.




Each wire pair


16


,


18


,


20


and


22


defines a longitudinal axis


92


,


94


,


96


and


98


, respectively, and an axial length


100


,


102


,


104


, and


106


, respectively. Wires


60


and


62


of first wire pair


16


are twisted about longitudinal axis


92


and along axial length


100


. Similarly, wires


64


and


66


of second wire pair


18


are twisted about longitudinal axis


94


and along axial length


102


. Likewise, wires


68


and


70


of third wire pair


20


are twisted about longitudinal axis


96


and along axial length


104


. Also, wires


72


and


74


of fourth wire pair


22


are twisted about longitudinal axis


98


and along axial length


106


.




Each wire pair


16


,


18


,


20


and


22


also defines first portions


108


,


110


,


112


and


114


, respectively, near cable open end


56


and second portions


116


,


118


,


120


and


122


, respectively, at cable body


52


, as seen in FIG.


2


. Each first portion


108


,


110


,


112


and


114


is located axially between respective wire terminal ends


76


,


78


,


80


,


82


,


84


,


86


,


88


and


90


and each respective second portion


116


,


118


,


120


and


122


. Each first portion


108


,


110


,


112


and


114


is overtwisted along the entire length of each first portion, as seen in

FIG. 2

, to reduce crosstalk and increase performance of connector


10


and mechanically strengthen wire pairs


16


,


18


,


20


and


22


. In particular, first portions


108


,


110


,


112


and


114


are overtwisted with a first degree of twist about respective longitudinal axes


92


,


94


,


96


and


98


of wire pairs


16


,


18


,


20


and


22


. The first degree of twist of wire pair first portions


108


,


110


,


112


and


114


is preferably about 360 degrees to 980 degrees about respective longitudinal axes


92


,


94


,


96


and


98


for the length of each respective first portion


108


,


110


,


112


and


114


. The optimum first degree of twist is about 720 degrees along the respective lengths of each of the first portions which is within 8.0 to 10 mm of the terminal ends. The first degree of twist of first portions


108


,


110


,


112


and


114


is preferably substantially greater than a second degree of twist at second portions


116


,


118


,


120


and


122


. The second degree of twist is about 360 degrees about respective longitudinal axes


92


,


94


,


96


and


98


of wire pairs


16


,


18


,


20


and


22


. Preferably, the first degree of twist is about twice the second degree of twist.




The degree of twist is the number of rotations or degrees of rotation the wire makes about the longitudinal axis per unit length along the longitudinal axis.




Assembly of electrical connector


10


includes preparing cable


14


for insertion into connector body


12


by initially overtwisting first portions


108


,


110


,


112


and


114


of respective wire pairs


16


,


18


,


20


, and


22


. The cable jacket


54


surrounds first portions


108


,


110


,


112


and


114


with wire terminal ends


76


,


78


,


80


,


82


,


84


,


86


,


88


and


90


extending though and beyond cable open end


56


. Overtwisting the wire pairs


16


,


18


,


20


, and


22


helps to maintain the wire pairs


16


,


18


,


20


, and


22


in a twisted state.




Cable


14


can then be inserted through access opening


30


, into connector body inner cavity


28


and crimped in a conventional manner. The overtwisting of wire pairs


16


,


18


,


20


, and


22


provides stability and rigidity to the wire pairs, particularly during crimping thereof by the connector strain relief




Once cable


14


is secured within electrical connector


10


, the wire pairs and their terminal ends are connected to their respective terminal positions or assignments


1


through


8


. In particular, wire pair


16


is attached to terminal positions


1


and


2


, wire pair


18


is attached to terminal positions


4


and


5


, wire pair


20


is attached to terminal positions


3


and


6


, and wire pair


20


is attached to terminal positions


7


and


8


. For example, terminal ends


76


and


78


of wires


60


and


62


, respectively, of wire pair


16


are connected to pins


46


at terminals


1


and


2


, respectively, via insulation displacement ends


50


of pins


46


. The signals of wires


60


and


62


are cancelled due to the twisting of the two wires


60


and


62


. Since the wire pair


16


is overtwisted at first portion


108


, any spaced between the wires


60


and


62


are eliminated and the wire pair


16


is made more compact. The compactness and elimination of spaces between the individual wires


60


and


62


of wire pairs


16


ensures less return loss or reflective signal thus increasing performance of the connector, particularly in high speed data transmissions. The remaining wire pairs


18


,


20


and


22


and their respective wires


64


,


66


,


68


,


70


,


72


and


74


are connected to electrical contacts


46


in a similar manner and operate in a similar fashion.




Additionally, the overtwist of wire pairs


16


,


18


,


20


and


22


maintains the twist between the individual wires of each wire pair to within close proximity of electrical contacts


46


, thereby reducing the separation distance of the individual wires. For example, the twist of wires


60


and


62


of wire pair


18


is maintained until separated for connection to electrical contacts


46


at terminal positions


1


and


2


. The distance d, as seen in

FIG. 2

, defined between the point offirst separation of wires


60


and


62


and the point of connection of wires


60


and


62


with electrical connectors


46


is minimized to reduce the separation of wires


60


and


62


. By minimizing the distance d or separation of wires


60


and


62


and maintaining the twist of wires


60


and


62


up to the open end


56


of cable


14


, the signals of wires


60


and


62


cancel each other more effectively, thereby reducing crosstalk. This distance d is also minimized for the remaining wire pairs


18


,


20


and


22


and their respective wires


64


,


66


,


68


,


70


,


72


and


74


in the same manner. Preferably, the overtwist of wire pairs


16


,


18


,


20


and


22


is maintained to within about 8-10 mm of electrical contacts


46


.




Once wire pairs


16


,


18


,


20


and


22


are properly connected to their respective electrical contacts


46


, electrical connector is connectable with a mating connector adapted to receive output end


26


of connector


10


. Spring lock tab


36


secures connector


10


within the mating connector.




While a particular embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.



Claims
  • 1. An electrical connector, comprising:a dielectric body having an input end and an output end opposite said input end; first and second electrical contacts located at said output end; a twisted wire pair connected to said first and second electrical contacts, said twisted wire pair defining an axial length and including first and second wires twisted along said axial length and having first and second terminal ends, respectively, said first and second terminal ends being connected to said first and second electrical contacts, respectively, and said twisted wire pair including first and second portions with said first portion being located axially between said second portion and said terminal ends of said first and second wires, said first portion having a first degree of twist about a longitudinal axis of said twisted wire pair, and said second portion having a second degree of twist about said longitudinal axis of said twisted wire pair, said first degree of twist being substantially greater than said second degree of twist.
  • 2. An electrical connector according to claim 1, whereinsaid first portion of said twisted wire pair is located near said electrical contacts.
  • 3. An electrical connector according to claim 1, whereinsaid output end of said dielectric body is connectable to a mating connector.
  • 4. An electrical connector according to claim 1, whereinsaid first degree of twist of said first portion is about 360 degrees to 980 degrees.
  • 5. An electrical connector according to claim 4, wherein said first degree of twist is about 720 degrees.
  • 6. An electrical connector according to claim 1, whereinsaid first and second electrical contacts include insulation displacing ends, respectively, for connection to said first and second wires.
  • 7. An electrical connector according to claim 6, whereinsaid dielectric body includes an aperture with an access opening at said input end; and said first twisted wire pair is received in said aperture through said access opening.
  • 8. An electrical connector, comprisinga dielectric body having an input end and an output end opposite said input end and a plurality of electrical contacts located at said output end; a cable extending into said input end, said cable including a plurality of twisted wire pairs for connection to said electrical contacts, each of said twisted wire pairs including, an axial length, first and second wires twisted along said axial length, said first and second wires having terminal ends, respectively, each of said terminal ends being connected to one of said electrical contacts, and each of said twisted wire pairs defining first and second portions with said first portion being located axially between said second portion and said electrical contacts, each of said first portions having a first degree of twist about a longitudinal axis of each of said twisted wire pairs, respectively, and each of said second portions having a second degree of twist about each of said longitudinal axes of each said twisted wire pairs, respectively, and said first degree of twist being substantially greater than said second degree of twist.
  • 9. An electrical connector according to claim 8, whereinsaid output end being adapted for connection with a mating connector.
  • 10. An electrical connector according to claim 8, whereinsaid first degree of twist of each of said first portions of said twisted wire pairs is about 360 degrees to 980 degrees.
  • 11. An electrical connector according to claim 10, whereinsaid first degree of twist is about 720 degrees.
  • 12. An electrical connector according to claim 8, whereinsaid first portions of each of said twisted wire pairs are located near said electrical contacts.
  • 13. An electrical connector according to claim 12, whereinsaid first portions of each of said twisted wire pairs are located less than 10 mm from said electrical contacts.
  • 14. A met hod of terminating wires to an electrical connector, comprising the steps of:twisting together first and second wires to a form a first twisted wire pair having a longitudinal axis and first and second portions, with the first portion being axially between the second portion and terminal ends of the first and second wires; overtwisting the first portion of the first twisted wire pair about the longitudinal axis so that the degree of twist about the longitudinal axis at the first portion is substantially greater that the degree of twist about the longitudinal axis at the second portion; and connecting the terminal ends of the first and second wires to first and second electrical contacts, respectively, of the electrical connector.
  • 15. A method in accordance with claim 14, further comprising the step ofinserting the first twisted wire pair into a dielectric body of the electrical connector after overtwisting the first portion of the first wire pair.
  • 16. A method in accordance with claim 14, further comprising the step ofconnecting an output end of the electrical connector with a mating connector after connecting the first and second wires with the first and second electrical connectors, respectively, the first and second electrical contacts being located at the output end.
  • 17. A method in accordance with claim 14, whereinthe overtwisted first portion of the first twisted wire pair is located near the first and second electrical contacts once the first and second wires are connected to the first and second electrical contacts, respectively.
  • 18. A method in accordance with claim 17, whereinthe overtwisted first portion is located a distance of less than 10 mm from the first and second electrical contacts.
  • 19. A method in accordance with claim 14, further comprising the steps oftwisting together third and fourth wires to a form a second twisted wire pair having a longitudinal axis and first and second portions, with the first portion being axially between the second portion and terminal ends of the third and fourth wires; overtwisting the first portion of the second twisted wire pair about the longitudinal axis so that the degree of twist about the longitudinal axis at the first portion is substantially greater that the degree of twist about the longitudinal axis at the second portion; and connecting the terminal ends of the third and fourth wires, respectively, to third and fourth electrical contacts, respectively, of the electrical connector.
  • 20. A method in accordance with claim 19, whereinthe first, second, third, and fourth electrical contacts form an array of electrical contacts located at an output end of the electrical connector.
US Referenced Citations (13)
Number Name Date Kind
5226835 Baker, III et al. Jul 1993 A
5350324 Guilbert Sep 1994 A
5911594 Baker, III et al. Jun 1999 A
6007368 Lorenz et al. Dec 1999 A
6123572 Ishii et al. Sep 2000 A
6176732 Schultz et al. Jan 2001 B1
6250951 Milner et al. Jun 2001 B1
6319048 Aekins et al. Nov 2001 B1
6431904 Berelsman Aug 2002 B1
6439911 Conorich Aug 2002 B1
6439920 Chen Aug 2002 B1
20010053627 Armistead et al. Dec 2001 A1
20020048990 Marowsky et al. Apr 2002 A1
Foreign Referenced Citations (1)
Number Date Country
07169526 Jul 1995 JP