CONCENTRIC MULTI-PAIR CABLE WITH FILLER

Technical Field

The present disclosure relates generally to devices for use in the telecommunications industry, and various methods associated with such devices. More particularly, this disclosure relates to a telecommunications cable having an arrangement of twisted conductor pairs.

Background

A wide variety of cable arrangements having twisted conductor pairs are utilized in the telecommunication industry. The increased need for high-speed communication transmissions (e.g., high-speed data transmissions) has placed a greater demand on twisted conductor pair systems, hi general, improvement has been sought with respect to existing cable technology for use with such systems, generally to better accommodate the increasing volume of data transmissions and accommodate the increased capacity demands of such systems.

Summary

One aspect of the present disclosure relates to a cable having a first group of inner twisted conductor pairs and a second group of outer twisted conductor pairs. The first group of pairs is twisted at a first twist rate; the second group of pairs is twisted at a second twist rate. Another aspect of the present disclosure relates to a method of manufacturing a cable having first and second groups 'of twisted conductor pairs that are twisted at different twist rates.

A variety of examples of desirable product features or methods are set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing various aspects of the disclosure. The aspects of the disclosure may relate to individual features as well as combinations of features. It is to be understood that both the foregoing general description and the following detailed description are explanatory only, and are not restrictive of the claimed invention.

Brief Description of the Drawings

FIG. 1 is a perspective view of a multi-pair cable, according to the principles of the present disclosure;

FIG. 2 is schematic, cross-sectional view the multi-pair cable of FIG. 1, taken along line 2-2, showing a filler and a plurality of twisted conductor pairs; and

FIG. 3 is a cross-sectional view of the filler of FIG. 2, shown in isolation and with only one twisted conductor pair.

Detailed Description

Reference will now be made in detail to various features of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

FIG. 1 illustrate a multi-pair cable 10 having features that are examples of how inventive aspects in accordance with the principles of the present disclosure may be practiced. Preferred features of the disclosed multi-pair cable are adapted for increasing the volume or number of data transmissions carried over the cable in comparison to conventional cables; and thereby increasing the capacity of communication applications utilizing the disclosed multi-pair cable.

Referring to FIGS. 1 and 2, the cable 10 of the present disclosure includes a plurality of twisted conductor pairs 12 surrounded or covered by a jacket 16. The twisted conductor pairs 12 include two insulated conductors twisted about one another along a longitudinal axis.

In the illustrated embodiment, the jacket 16 of the cable 10 includes a first inner jacket layer 18 and a second outer jacket layer 20. A metal layer 22 is disposed between the inner jacket layer 18 and the outer jacket layer 20. The metal layer 22 provides shielding to protect the twisted conductor pairs 12 from interference that can adversely affect signal transmissions through the cable, such as electromagnetic radiation. The inner jacket layer 18 separates the twisted conductor pairs 12 from the shielding or metal layer 22. In the illustrated embodiment, a drain wire 48 is provided to ground or terminate the shield or metal layer 22 of the jacket 16.

In one embodiment, the inner jacket layer 18 and the outer jacket layer 20 are made of a non-conductive material such as polyvinyl chloride (PVC), for example. Other types of non-conductive materials can be used for one or both of the jacket layers. The metal layer 22 is preferably made of a shielding material, such as aluminum, for example. Other types of materials and/or constructions adapted for blocking electromagnetic radiation, such as a copper foil tape or screen, a metallic braid shield, or a corrugated metal shield can also be used in accordance with the principles disclosed.

Referring to FIG. 2, the twisted conductor pairs 12 of the cable 10 are arranged in groupings of twisted pairs, including a first grouping of inner twisted conductor pairs 24 and a second grouping of outer twisted conductor pairs 26. In the illustrated embodiment, the first grouping includes four inner twisted conductor pairs 24, and the second grouping includes twelve outer twisted conductor pairs 26. The illustrated multi-pair cable 10 is accordingly a 16-pair cable.

As shown in FIGS. 1-3, the multi-pair cable 10 further includes a filler 14. The filler 14 defines a number of pockets 28 (FIG. 3). Each of the inner twisted conductor pairs 24 is positioned with one of the number of pockets 28. hi the illustrated embodiment, the filler 14 has four pockets 28 defined by radial extensions 30. The radial extensions 30 separate each of the inner twisted conductor pairs 24 from the other inner twisted conductor pairs. , _;

Referring to FIG. 3, the radial extensions 30 of the filler 14 each have a first end 32 and a second end 34. The first ends 32 of the radial extensions 30 are joined and define a center 36 of the filler 14. The second ends 34 are free ends. Each of the radial extensions 30 has a length Ll that extends from the first end 32 or center 36 to the free end 34. The length Ll of the radial extensions 30 is preferably greater than a diameter Dl of the inner twisted conductor pairs 24.

Still referring to FIG. 3, the filler 14 also includes retaining members 38 located at the free ends 34 of the radial extension 30. The retaining members 38 are arranged and configured to retain the inner twisted conductor pairs 24 within the pockets 28 of the filler 14 (FIG. 2). In particular, each of the retaining members 38 has a length L2. The retaining members 38 are oriented such that the length L2 of the retaining member 38 is transverse to the length Ll of the respective radial extension 30. The length L2 is provided so that adjacent end portions 40 of adjacent

retaining members 38 contain or hold the inner twisted conductor pair 24 within the pocket 28 of the filler.

That is, a distance D2 between adjacent end portions 40 of adjacent retaining members 38 is less than the diameter Dl of the inner twisted conductor pair 24. One or both of the retaining members 38 and the radial extensions 30 is therefore, preferably, made of a material that flexes to permit placement of the inner twisted conductor pair 24 within the pockets 28. In one embodiment, the filler 14, i.e., the radial extensions 30 and the retaining members 38 are made of a non- conductive material. Other materials can be used to manufacture the filler 14 in accordance with the principles disclosed. Because the distance D2 between the end portions 40 of the retaining members 38 is less than the diameter Dl of the inner twisted conductor pairs 24, the pairs 24 are retained within the pockets 28 of the filler 24.

In addition to retaining and separating the inner twisted conductor pairs 24, the filler 14 also functions to space or provide separation between the first grouping of inner twisted conductor pairs 24 and the second grouping of outer conductor pairs 26 (see FIG. 2). In particular, the length Ll of the radial extensions 30 is greater than the diameter Dl of the inner twisted conductor pairs 24 such that the retaining members 38 and radial extensions 30 provide a separation between the two groupings of twisted conductor pairs.

Referring again to FIG. 2, the grouping of inner twisted conductor pairs 24 positioned within the pockets 28 of the filler 14 defines an inner core 42 of the cable 10. As can be understood from the preceding description, the inner core 42 has a circumference 46 generally defined by the radial extensions 30 and the retaining members 38 of the filler 14. The grouping of outer twisted conductor pairs 26 surrounds the inner core 42 and defines a concentric outer layer 44 of twisted conductor pairs. The outer twisted conductor pairs 26 of the outer layer 44 are spaced at approximately equal intervals about the circumference 46 of the inner core 42. The jacket 16, including the inner jacket layer 18, the metal layer 22, and the outer jacket layer 20, covers the inner core 42 and the outer layer 44 of twisted conductor pairs.

Preferably, the inner core 42 of the multi-pair cable 10 is twisted at a first twist rate Rl . The first twist rate Rl is the rate at which both of the filler and the first grouping of inner twisted conductor pairs 24 are turned or twisted in unison

about a central axis of the filler or inner core. In one embodiment, the first twist rate Rl is approximately 4.8 twists per linear foot. In addition, each of the inner twisted conductor pairs 24 of the inner core 42 has an individual conductor twist rate Ra, Rb, Rc, Rd. The individual conductor twist rate Ra, Rb, Rc, Rd of each of the inner twisted conductor pairs 24 is preferably different from the individual conductor twist rates of the other inner twisted conductor pairs. In one embodiment, the individual conductor twist rates Ra, Rb, Rc, Rd of the inner twisted conductor pairs are between about 27.3 twists per linear foot and 36.8 twists per linear foot.

While the inner core 42 is twisted at the first twist rate Rl, the outer layer 44 is preferably twisted at a second twist rate R2 that is different than the first twist rate Rl of the inner core 42. The second twist rate R2 is the rate at which all of the outer twisted conductor pairs 26 are turned or twisted in unison about a central axis of the cable or outer layer. In one embodiment, the second twist rate R2 is approximately 1.333 twists per linear foot of cable. In addition, each of the outer twisted conductor pairs 26 of the outer layer 44 has an individual conductor twist rate Re, Rf, Rg, Rh. In the illustrated embodiment, the twelve outer twisted conductor pairs 26 preferably have one of four different conductor twist rates Re, Rf, Rg, Rh, and are arranged in a sequence as shown in FIG. 2 according to the particular individual conductor twist rate.

Preferably, each of the individual twist rates Re, Rf, Rg, Rh of the outer twisted conductor pairs 26 is outside the range of twist rates Ra, Rb, Rc, Rd (27.3 to 36.8 twists per foot) of the inner twisted conductor pairs 24. By this arrangement, the orientation of each of the inner twisted conductor pairs 24 is non- parallel to the orientation of the outer twisted conductor pairs 26 to reduce the likelihood of crosstalk. More preferably, each of the individual twist rates Re, Rf, Rg, Rh of the outer twisted conductor pairs 26 is less than each of the individual twist rates Ra, Rb, Rc, Rd of the inner twisted conductor pairs 24. In one embodiment, the individual conductor twist rates Re, Rf, Rg, Rh of the outer twisted conductor pairs 26 are between about 12.4 twists per linear foot and 27.0 twists per linear foot.

To manufacture the disclosed multi-pair cable 10, the inner twisted conductor pairs 24 are positioned within the pockets 28 of the filler 14. As previously discussed, each of the inner twisted conductor pairs 24 preferably has an individual conductor twist rate that is different from the individual conductor twist

rates of the other inner twisted conductor pairs. The filler 14 and the inner twisted conductor pairs 24 (i.e., the inner core 42) are then twisted, in unison about the central axis of the filler 14, at an initial twist rate RO (FIG. 3 - showing only one twisted conductor pair 24 for purposes of clarity). In one embodiment, the initial twist rate RO is approximately 4 twists per linear foot of cable.

As can be understood, because each of the inner twisted conductor pairs 24 is already twisted at a particular individual conductor twist rate, the individual conductor twist rates of the inner twisted conductor pairs 24 change when the entire inner core 42 is twisted. Preferably, each of the inner twisted conductor pairs 24 has the same direction of twist (e.g. a right-hand twist or a left-hand twist) as the direction in which the inner core 42 is initially twisted. By this, the individual conductor twist rates of the inner twisted conductor pairs 24 increase as the inner core 42 is twisted.

After the inner core 42 has been twisted at the initial twist rate RO, the second grouping of outer twisted conductor pairs 26 are positioned concentrically about the circumference 46 of the inner core 42. The outer layer 44 and the inner core 42 are then twisted at the second twist rate R2 previously described (i.e. the outer twisted conductor pairs 26, the filler 14, and the inner twisted conductor pairs 24 are twisted in unison about the central axis of the cable or filler at the second twist rate). As can be understood, because each of the outer twisted conductor pairs 26 is already twisted at a particular individual conductor twist rate, the individual conductor twist rates of the outer twisted conductor pairs 26 change when the outer layer 44 is twisted. Preferably, each of the outer twisted conductor pairs 26 has the same direction of twist (e.g. a right-hand twist or a left- hand twist) as the direction in which the outer layer 44 is twisted. By this, the individual conductor twist rates of the outer twisted conductor pairs 26 increase as the outer layer 44 is twisted. The resulting individual conductor twist rates of each of the outer twisted conductor pairs 26 are the twist rates Re, Rf, Rg, and Rh previously described.

When the outer layer 44 is twisted at the second twist rate R2, the inner core 42 also twists in unison with the outer layer 44. Preferably, each of the inner core 42 and the outer layer 44 has the same direction of twist. By this, the twist rate of the inner core 42, and accordingly the twist rates of the inner twisted conductor pairs 24, increase as the outer layer 44 is twisted. The resulting twist rate

of the inner core 42 is the first twist rate Rl previously described. Likewise, the resulting individual conductor twist rates of each of the inner twisted conductor pairs 24 are the twist rates Ra, Rb, Rc ₅ ^" and Rd previously described.

The above specification provides a complete description of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, certain aspects of the invention reside in the claims hereinafter appended.