CN1171172A - Joins discrete conductors to form an integral ribbon cable for high-performance splices - Google Patents

Abstract

A method and fixture for aligning and connecting a plurality of discrete insulated jacketed conductors to facilitate handling of the conductors and insertion of the conductors into an electrical connector housing for termination thereto. The method includes the steps of selecting a plurality of discrete jacketed conductors to be arranged in at least two different planes, arranging and aligning the ends of the plurality of conductors in a side-by-side manner in a plane on a fixture, and joining the jacket of adjacent conductor ends to form an integral ribbon cable for ease of handling and termination. A preferred method of joining is by localized heating of the wire ends to melt and join the insulation sleeves. Alternatively, a performance enhancing load bar insert may be incorporated between the conductors downstream from the wire ends to separate the conductors and reduce cross-talk.

Description

Joins discrete conductors to form an integral ribbon cable for high-performance splices

The present invention relates to a method for joining the entry ends of separate conductors to form an integral ribbon cable for insertion or termination in an electrical connector such as a modular plug, and by using a loading A strip insert improves this plug, reducing crosstalk to improve performance. The standard or performance level in use today is labeled as Category V products, where the operating frequency can be 100MHz or higher. While the invention has general application to the preparation and alignment of wires to be terminated in splices, it has particular utility for the loading of modular plugs, which often must be installed in the field by a technician or at a small factory. Terminated by manual operation. The first approach, proposed several years ago, was the use of wire organizers into which the discrete wires were first loaded, aligning and positioning the wires for eventual entry into the splice. However, there are still some problems with the use of this organizer, since the free ends of the wires still have to be guided into the designated channels in the connector, so that stubbing of the ends can occur.

Although the application of this invention is extensive, for the sake of convenience, further description will be directed to a product well known in the art - the field of modular plugs, and the possibilities of the invention as it relates to the loading and performance improvement of modular plugs. applicability. Modular plugs are relatively inexpensive electrical connectors that are widely used in telephone and other data communication systems. Typically such plugs must be terminated by a technician in the field or in the factory by the installer who installs the cord. Typically, the cable to be terminated in the plug is a bundle of 4 twisted pairs of insulated multi-colored wire (8 rods total) within a cable jacket or insulating jacket. This bundle of cables may include a surrounding shield or a drain wire used in a shielded plug. In any case, in preparation for the cable to be eventually terminated in a plug, the cable jacket is stripped back to expose the pairs of insulated conductors. Thereafter, for the few insulated wires exposed, the wires are straightened and arranged in the desired order, generally side by side. The wires are then individually inserted into the splice housing and insulated through the blade terminations, a termination procedure known in the art. Recognizing these awkward procedures, loading bar inserts were developed to facilitate the loading process. A typical loading strip insert is described in US Patent 4,713,023. The invention herein includes wire positioning means for holding insulative splices in a row such that when the wire loading positioning means is in the housing, end alignment therein occurs below the final receiving cavity. The locating means includes cam means formed thereon for engaging the housing strain relief portion as the housing strain relief moves downwardly so that the locating means moves forwardly in the housing to fully seat the locating means in the there, and position the free end of the insulated conductor under the terminal.

In British Patent Application 2,249,222A, assigned to the assignee of the present patent, an electrical connector and insert therefor is described, wherein the invention relates to a plastic insert for such a connector, having a row of openings for guiding wires , each port is used to guide a single wire into the channel when the cable is inserted into the connector. The cable has at least one less conductor than the number of channels, and the insert has at least one solid blank to block one or more unused channels. The guidewire opening of the insert is defined by at least one longitudinal opening with a scalloped longitudinal edge.

US Patent 4,601,530, assigned to the assignee herein, describes a pre-wired organizer for modular plugs. In particular, the patent describes the process of preloading the wires into wire holders that hold the leading ends of the wires at the same spacing as the channels in the connector housing. The wire holder, supported by the wire, is then inserted into the mouth of the housing along the mouth of the housing until it thus communicates with the tapering throat of the access opening. Further advancement of the bundle of wires feeds the discrete wires through the wire holders into their respective passages guided by the throat while the wire holders remain adjacent to the tapering throat.

In recent developments a loading strip insert has been used with modular plugs while providing Category 5 levels of improved performance, however the known performance levels in this technology have been rejected by Glen Rock, Pennsylvania The Stewart connector system (ConnectorSystems) proposed. They propose a Category 5 operating modular plug employing a movable wire management lever, wherein the lever includes two rows of 4 through holes each for receiving the standard 8 conductors of the cable. To use management rods, users are advised to divide the wires into two identical groups, and cut each group of 4 wires at 45° angles so that no two wires are the same length. For prepared wires, the wires are individually fed into the holes of the wire organizers that are in sliding engagement with them, and then cut to the same length. For the loading step, the wire organizer is first pushed onto the end of the clipped wire and then inserted into the splice housing. In the manner of US Pat. No. 4,601,530, when the wire organizer fails to move forward, the wires are pushed out of the confines of the wire organizer into a position where they are individually terminated, as is known in the art. Although providing Category 5 performance, the assembly and termination of the modular plug is labor intensive.

The steps in which this invention supports the handling and loading of the modular plug in the accompanying application, and its ability to provide the speed at which the modular plug is factory terminated, will be apparent from the following description, especially when read in conjunction with the accompanying drawings.

The invention is directed to the field of electrical connectors, such as modular plugs, in which a number of insulating sheathed wires are inserted into and terminated in the plug, one such termination process being through insulation penetration. The method of the invention is particularly directed to the process of aligning and connecting a large number of discrete tape-sheathed wires which necessitate the use of heat, adhesive or tape to facilitate handling of the wires and insertion of the wires into the housing of a modular plug such as they are The termination is there. The step of thermally connecting includes aligning a plurality of wires in a side-by-side manner on a first jig, wherein the jig includes a plurality of heating elements each arranged to contact the insulating sheaths of adjacent pairs of wires. Thereafter, a second clamp of similar design and function is sandwiched against the opposite side of the insulating tape-sheathed wire, and an electric current is applied to the heating element to produce localized melting, bonding the insulating jackets of adjacent wires to each other. connected together. This method produces an integral ribbon cable which is easy to handle and terminate.

As an optional feature of the invention, in order to enhance the performance of the splice, a loading strip insert may be provided downstream of the connected wire end. A preferred loading strip insert features upper and lower surfaces for separating selected pairs of conductors. Within the confines of the connector or plug housing, the insert or spacer maximizes the separation of the selected pair and is realigned upstream into a plane for placement of the selected pair prior to connector termination and termination in many planes. The first embodiment comprises grooves on the upper and lower surfaces of the insert, while the second embodiment is a hollow rod like a separate member, which can be made of elastic material, plastic or a plastic-like tube.

Figure 1 is an exploded perspective view of an electrical connector, such as a modular plug, in which the method of the invention is practiced, further illustrating the use of an improved performance loading strip insert.

Figures 2 to 4 are cross-sectional views showing the sequence of connecting discrete conductors to form an integral ribbon cable according to the invention.

5 and 6 are side sectional views corresponding to the sequence shown in Figs. 2 and 3, respectively.

FIG. 7 is a cross-sectional view of the assembled modular plug shown in FIG. 1 .

FIG. 8 is a cross-sectional view through line 8-8 of FIG. 7. FIG.

Figure 9 is a perspective view of the loading strip insert of Figure 1, showing the preloaded position therein, with discrete conductors ready to be threaded therein.

FIG. 10 is a cross-sectional view of the prior art cable along line 10-10 of FIG. 1 showing the splices prior to being arranged in a plane for access to the loading strip insert of FIG. 9. FIG.

Figure 11 is a cross-sectional view of the priority loading strip insert of the invention taken along line 11-11 of Figure 1 .

12 is a cross-sectional view taken along line 12-12 of FIG. 1 showing the conductors realigned in planar relationship for entry into, for example, a modular plug prior to termination.

Figure 13 is a perspective view of a second loading strip insert which can be selectively removed.

Figure 14 is a perspective view similar to Figure 13, showing a third embodiment, without the use of an interposer, but with the provision of a spaced, separate arrangement of the wires.

Figure 15 is an enlarged longitudinal sectional view similar to Figure 7, showing the location of the loading bar of Figures 13 and 14 in phantom lines.

This invention relates to a method of joining a plurality of discrete insulated conductors to form an integral ribbon cable, and to the product thereof. More particularly, the invention is directed to an economical method of manually factory wiring, such as modular plugs, and the optional use of loading strip inserts to improve the performance of modular plugs.

Figure 1 shows a basic example of how the inventive method simplifies loading and termination of modular plugs. As shown in FIG. 1, a typical electrical connector 10 includes an insulating housing 12 formed by an open end 14 of a cable 16 for receiving a plurality of conductors, and a terminating terminal 18 communicating with an array of cable conductor receiving channels. The channel also communicates with an internal cavity 20 which opens into the end 14 . By way of further understanding, the multi-conductor cable 16 is characterized as a twisted pair cable in which selected pairs of cables are preferably twisted together. That is, a typical cable for an 8-position modular plug exhibits 4 twisted pairs of insulated conductors. By way of further example, under specification TIA/EIA-568, the preferred pair arrangement of conductors or wires for modular plug terminal numbers is as follows: 1-2, 3-6, 4-5 and 7-8.

As specifically mentioned above, the invention is used to attach thin wires to electrical terminals, with or without the aid of loading strip inserts or conductor organizers, as explained hereinafter. However, the preferred method consists in using the invention with a loading strip insert 22, as shown in Figure 1 and subsequent figures. Although there are variants or embodiments of loading bar inserts, from relatively solid bodies to members with low dielectric constants such as hollow cylinders, since it is about the method of connection, further discussion will now be directed to Figures 1 and 7 A solid embodiment of . The preferred embodiment of the insert is cast or formed from a rod or shaped object, comprising upper and lower surfaces 24 and 26, a rear portion 28 and a taper to a cable receiving channel 32 located below a conductor terminal blade or terminal 23. Converging or expanding front surface 30, see FIG. 9 . Along the upper and lower surfaces 24 and 26 are pairs of slots or grooves 34, 36 into which selected pairs of conductors pass or are received. For the above pair arrangement, pairs 3-6 and 7-8 are secured in the upper slot 34, while the remaining two pairs are secured in the lower slot 36. Note further that the upper slot containing pairs 3-6 includes an end splitter 40 for separating the wires and centering the wire pairs into their numerically designated termination locations.

Once the selected pair is positioned in the insert, or the insert is not used, the discrete insulated wires 1 to 8 are placed between the interlayers of the workbench fixture 44 as shown in Figures 2 to 6, which is the preferred implementation for connecting the discrete wires method. In any event, the pair of fixtures each includes a planar body 46 having a plurality of parallel resistive heating elements 48 arranged along a mating surface 50 . As best seen in Figures 5 and 6, the opposing surface 52 includes means 54 for supplying electrical current to the heating element 48 to generate heating. Heating elements 48 are secured between adjacent wires in a row, on the outside of the wires see FIG. 3 . In the examples of FIGS. 2 to 4, if the number of wires is "n", the number of heating elements is "n+1". For each clamp secured in compressive relation to the diverging wires, note the direction of the arrows in FIG. 3, current may be supplied to heating element 48 through means 54 to melt and join the insulated wires, creating an integral ribbon cable at the ends. That is, the individual clamps 44 are put together to hold and secure the discrete wires exactly on a centerline of preferably 0.040", wherein a heating element 48, such as a nichrome (heat resistant) alloy heating wire, Also spatially separated by a distance of 0.040". With this arrangement, the heating elements, including the outermost heating elements, act as miniature "V" shaped blocks. For the separated clamps, pay attention to the direction of the arrow in FIG. 4 , it can be seen that the wires are connected together and present a fan-shaped outline 55 . Thereafter, the connected wires are trimmed transversely through the scalloped profile 55 , presenting an integral element for insertion and termination in the modular plug. This profile provides further advantages to the insertion and termination process, as explained later. Another advantage of using this type of fixture is the rather quick cooling of the system, which allows for quick flipping when repeated with new and different sets of wires.

FIGS. 7 and 8 show the integral components inserted and pre-terminated in the modular plug with the connected wires under a plurality of terminating blades 23 . The channels 32 that receive the connected wires are generally a series of circular communicating portions, wherein the upper and lower surfaces are scalloped 60 , the portions being separated by two spaced apart opposing ribs 62 . Truncation may occur for the usual insertion of discrete wires where the wires are not precisely aligned with the channel. However, for this invention, where the connecting webs between adjacent conductors have been altered by the newly pressed profile 55, the truncation problem is greatly reduced. Also, by reshaping or changing the wire profile, it is now possible to use larger diameter wires than previously possible. That is, the form compression from the scalloped profile 55 creates a spacing that eases the insertion process and even allows the use of wires such as over 0.040" in diameter.

According to the preferred method of practicing the invention, a jig is prepared employing a printed circuit board with 9 loops of SST wire arranged in parallel on a 0.040" centerline with the same spacing as the insulated wire. For a pair arranged in a sandwich For this clamp of 8 insulated wires, 7 to 10 amps are applied to the SST wire loop for 5 to 2 seconds to connect the insulated wires. After trimming, the connected wires are easily inserted into the modular plug.

There may be another way to connect the wire ends. For example, when the conductors are arranged side-by-side in a suitable fixture, adhesive or tape may be applied to the ends to form an integral ribbon cable at least on one end. These alternative methods, however, do not provide the advantages of reshaping the wire ends found in heat joining methods. Turning now to several embodiments of loading bar inserts, shown in Figures 1, 7, 9 and 11-15, it should again be noted that this is an optional feature for the above mentioned wire connections. However, some brief recaps are helpful before proceeding to describe this optional feature. As is known in the art, the multi-conductor cable 16 shown in cross-section in FIG. 10 is characterized as a twisted pair cable in which selected pairs of conductors 38 are preferably twisted together. That is, a typical cable for an 8-position modular plug exhibits four twisted pairs of insulated conductors. By way of further example, under specification TIA/EIA-568A, the preferred pair arrangement of conductors or wires for modular plug terminal counts is as follows: 1-2, 3-6, 4-5 and 7-8. This will be discussed in more detail hereafter. It should be noted, however, that in the practice of the prior art it is believed that the "1/2 inch no twist" rule must be followed in the preparation and termination of wires in a modular plug. That is, the twisted pair must remain twisted except for about 1/2 inch of the end of each wire which can be left untwisted for termination. It has been found that by employing the optional features herein, this rule for modular splices can be violated without increasing near-end crosstalk (NEXT). The key factor is that the degree of physical separation of interfering wire pairs (mainly 3-6 pairs separated from each other around the middle of the plug) is more important than maintaining a tight twist. Crosstalk is inversely proportional to the distance between interfering wires.

Continuing now with the remaining figures, FIG. 9 shows a first embodiment of a loading strip insert 22 that can be removably received in the housing 10 through the opening 14 . This preferred insert formed of insulating material is described above. Note that by providing an upper slot and a lower slot, the separation of the wires in the housing 10 is increased. Also, by providing a frontal or diverging surface 30, each pair of wires along the upper surface 24 is in each plane before returning to a single plane as shown in FIG. These factors contribute significantly to the improved performance of the plug because crosstalk is reduced by increasing the separation distance of the conductors.

Figures 13 to 15 show a second embodiment of a loading strip insert 64. The main purpose of the insert is to spatially separate the wires into multiple planes before realignment for termination. This new insert is well satisfy this purpose. Insert 64 comprises a hollow member, which may be a cylinder of elastomeric material, styrofoam, or plastic, in which the selected pair of wires is placed on top or bottom. In the example of Figure 13, key pairs 3-6 are along the top and the remaining pairs are below the insert. In particular, in different embodiments, the dispersion form of the wires varies. However, the common feature here is that the key pairs 3-6 and 4-5 phase separate. By using hollow members, the wires maintain a spacing when inserted into the connector housing to reduce crosstalk.

For the two embodiments shown in the several figures, it can be seen that after bonding of the wires to the inserts 22, 64, the individual wires arranged in the desired order merge from their respective planes into a common plane for termination. catch. It has been found that a single strip of side-by-side wires is easier to insert into the channel of the connector than many discrete wires. This realization led to the wire connection technique described above.

A distinct advantage can be attributed to the integrated wire connection method and performance-enhancing features. According to the wire connection method described above, the wires are fixed relative to each other after connection. This advantage is best illustrated by Figure 14, wherein the rod or cylinder like insert 64 has been removed. Since the wires are secured at their respective ends, that is, in the cable 52 and the connection area 66, the wires do not spring back into a common plane, as would be expected with only one fixed end. Thus, when the wires are connected, as described above, they can be easily inserted into the connectors, as discussed above. Figure 15 shows the relative positions of the leads with and without the insert 64.

Claims (10)

1. A method of aligning and connecting a large number of discrete sheathed conductors to facilitate handling of said conductors and inserting said conductors into electrical connector housings for termination therein, said method comprising the steps of: (a) a selection of discrete sheathed conductors arranged in at least two different planes, (b) arranging and aligning said plurality of conductors in a side-by-side manner in a common plane on the first fixture, (c) joining the insulating jackets of adjacent said ends to form an integral ribbon cable for ease of handling and termination. 2. A method according to claim 1, wherein said connecting is a method selected from heating, adhesive or sticking with tape. 3. A method according to claim 1, wherein the connection is made by heating, said insulating sheathed conductor having a circular initial configuration, said heating altering said configuration by displacing a portion of said insulation. 4. The method of claim 3 wherein said heat is generated by heating elements disposed along said fixture. 5. A method according to claim 4, wherein the number of said conductors is "n" and the number of said heating elements is "n+1". 6. A method of aligning and connecting a plurality of discrete sheathed conductors to facilitate handling of said conductors and inserting said conductors into electrical connector housings for termination therein, said method comprising the steps of: (a) aligning said plurality of conductors in a side-by-side manner on a first jig, wherein said jig includes a plurality of heating elements each arranged so as to be in contact with the insulating sheaths of an adjacent pair of said conductors; touch, (b) sandwiching a second clamp of similar design and function against the opposite edge of said sheathed conductor, (c) applying an electric current to said heating element to cause localized melting to join the insulating sheaths of adjacent conductors to each other to form a ribbon cable for ease of handling and termination. 7. A wire connection fixture for joining together a plurality of discrete, parallel insulated conductors to form an integral ribbon cable at the ends of said conductors, said fixture comprising a pair of substantially planar insulating elements for compressively bond said wires, and heating elements arranged in a parallel manner along opposite major surfaces of said planar element, wherein said wires are in number "n", heating elements are at least "n+1", and the inner heating element is connected to two The insulation of two adjacent wires and the means for heating the above-mentioned heating element are in contact so as to join the above-mentioned insulated wires into an integral member. 8. Electrical connectors of the plug assembly type for mating with socket type connectors, wherein a plurality of conductors are terminated therein for electrical engagement with corresponding contacts in said socket, said plug assembly comprising an insulating housing having a conductor receiving end, a conductor receiving end, a channel communicating within the end of said receptacle, said channel having a hollow insert for receiving said plurality of conductors and securing said conductors in a manner to improve crosstalk performance of the plug assembly, said insert having an upper surface and a lower surface along which a plurality of slots are arranged to receive selected pairs of the aforementioned conductors. 9. An electrical terminal according to claim 8, wherein said insert includes a tapering wall facing said conductor terminating end such that said selected conductors along said upper surface are directed to selected conductors along said lower surface. pair of conductors located between them. 10. An electrical connector according to claim 9, wherein the free ends of said conductors are arranged in parallel in a common plane and are connected together at the terminating ends of said conductors.

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