Patent Application
20230213723
The disclosure relates generally to bundled drop assemblies including optical fibers, and specifically to bundled drop assemblies including multiple layers of drop cables in which the layers are wound around a central strength member in the same winding direction. Optical fibers are used to transmit data optically between various points in a network. Such optical fibers may be arranged in cables originating at data hubs, and the cables may include branches that drop at various locations to deliver data to nodes in the network. A variety of cable designs exist that provide such branching within a transmission network.
According to an aspect, embodiments of the disclosure relate to a bundled drop assembly. The bundled drop assembly includes a central member. The bundled drop assembly also includes an inner layer of subunits laid in a winding direction around the central member. The inner layer of subunits includes at least one subunit containing one or more optical fibers. Further, the bundled drop assembly includes at least one further layer of subunits laid around the inner layer of subunits in a same winding direction as the inner layer of subunits. The at least one further layer of subunits includes at least one subunit containing one or more optical fibers. The at least one further layer of subunits includes an outer layer of subunits that is the outermost layer of the bundled drop assembly.
According to another aspect, embodiments of the disclosure relate to a method of preparing a bundled drop assembly. In the method, an inner layer of subunits having a plurality of optical fibers is wound around a central member in a first winding direction. Each of at least one further layer of subunits is wound around the inner layer of subunits in a second winding direction. The at least one further layer of subunits includes a plurality of optical fibers. The at least one further layer of subunits includes an outer layer of subunits that is the outermost layer of the bundled drop assembly, and the second winding direction is the same as the first winding direction.
According to a further aspect, embodiments of the disclosure relate to a bundled drop assembly. The bundled drop assembly includes a central member. Further, the bundled drop assembly includes an inner layer of subunits having a plurality of optical fibers wound around the central strength member in a first winding direction. At least one binder is wrapped around the inner layer of subunits. An outer layer of subunits having a plurality of optical fibers is wound around the binder and the inner layer of subunits in a second winding direction. The first winding direction is the same as the second winding direction, and the outer layer of subunits is the outermost layer of the bundled drop assembly.
Additional features and advantages will be set forth in the detailed description that follows, and, in part, will be readily apparent to those skilled in the art from the description or recognized by practicing the embodiments as described in the written description and claims hereof, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understand the nature and character of the claims.
The accompanying drawings are included to provide a further understanding and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment(s), and together with the description serve to explain principles and the operation of the various embodiments.
Referring generally to the figures, various embodiments of a bundled drop assembly having increased stiffness and layers of subunits with unidirectional winding are provided. As will be discussed more fully below, the bundled drop assembly is configured to substantially diminish or eliminate unwinding of subunits that produces undesirable bulging in the cable as a result of twisting. The bundled drop assembly includes a central member around which a first layer of subunits is wound. At least one further layer of subunits is wound around the first layer of subunits. Applicant has found that, when the first layer of subunits is wound in a different direction that a second layer of subunits, twisting can result in one layer tightening and the other layer unwinding, amplifying the effect of unwinding during twisting and producing the aforementioned bulging. According to the present disclosure, each layer of subunits is wound in the same direction so that the subunits react more uniformly during twisting. Further, Applicant has found that by increasing the stiffness of the bundled drop assembly, the effects of twisting are further reduced because the twist is spread over a longer cable length. Exemplary embodiments of the bundled drop assembly and method of manufacturing same will be described in greater detail below, and these exemplary embodiments are provided by way of illustration, and not by way of limitation.
In the embodiment depicted in
In the embodiment depicted in
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In the embodiment depicted, the central member 13 in the form of a central strength member 14 includes a strength element 26 that is optionally surrounded by a jacket layer 28. In embodiments, the strength element 26 is, for example, a fiber-reinforced plastic (FRP) rod, a metal wire, or resin-impregnated yarns or strands, among others. In embodiments, the strength element 26 has a diameter of at least 3.0 mm. In further embodiments, the strength element 26 has a diameter of at least 4.0 mm. In still further embodiments, the strength element 26 has a diameter of at least 4.5 mm. In embodiments, the strength element 26 has a diameter of up to 5.0 mm. Further, in embodiments, the central strength member 14 has an outer diameter of at least 5.0 mm, and in embodiments, the central strength member 14 has an outer diameter of up to 15 mm. The jacket layer 28 is provided where the diameter of the strength element 26 is less than the desired final diameter of the central strength member 14. For example, if the desired diameter of the central strength member 14 is 5.0 mm and the strength element 26 has a diameter of 4.5 mm, then the jacket layer 28 will have a thickness of 0.25 mm. In another example, if the desired diameter of the central strength member 14 is 5.0 mm and the strength element 26 has a diameter of 5.0 mm, then the central strength member 14 may not include a jacket layer 28 at all.
In the embodiment depicted, each optical fiber drop cable 16 includes one or more optical fibers 30. The optical fibers 30 are surrounded by a cable jacket 32. The cable jacket 32 has an outer surface 34 and an inner surface 36. The inner surface 34 defines a central bore 38 in which the optical fibers 30 are disposed. In the embodiment depicted, the optical fibers 30 are arranged in a loose-tube configuration within the central bore 38. However, in other embodiments, the optical fibers 30 may be arranged in another configuration, such as in one or more ribbons, which may be in a linear, stacked, or rolled configuration. Further, each optical fiber drop cable 16 is depicted with twelve optical fibers 30, but in embodiments, each optical fiber drop cable 16 includes form one to twenty-four optical fibers 30. Additionally, in embodiments, the central bore 38 may also be filled with a variety of filling material, such as strength members (such as aramid, cotton, basalt, and/or glass yarns), water blocking gels or powders, and/or fire retardant materials, among others. The optical fiber drop cables 16 are configured to drop from the bundled drop assembly 10 at various locations along the length of the bundled drop assembly 10 so that the optical fibers 30 can deliver optical signals to installations at the drop locations. Additionally, in embodiments, the central member 13 may be an optical fiber cable substantially similar to the optical fiber drop cable 16. Further, in embodiments, the optical fiber cable central member may carry several hundred or even thousands of optical fibers (e.g., RocketRibbon™ cable, available from Corning Incorporated, Corning, N.Y.).
In the embodiment depicted, each electrical conductor cable 18 includes one or more wires 40 having a wire conductor 42 and a wire jacket 44. In embodiments, the wire conductor 42 is a stranded or solid wire. Further, in the embodiment depicted, the electrical conductor cable 18 includes three wires 40, e.g., a hot, a neutral, and a ground wire for single phase power. In embodiments, the one or more wires 40 are surrounded by a subunit jacket 46. The electrical conductor cables 18 are configured to carry electrical power, and similar to the optical fiber drop cables 16, the electrical conductor cables 18 can drop from the bundled drop assembly 10 at various locations to delivery electrical power to installations at the drop location. In embodiments, an electrical cable substantially similar to the electrical conductor cable 18 may be used as the central member 13 of the bundled drop assembly 10.
As mentioned above, the bundled drop assembly 10 may include one or more filler units 20. In embodiments, the filler units 20 may be used to provide a complete layer if optical fiber drop cables 16 or electrical conductor cables 18 are not needed for the particular installation. Additionally, in embodiments, the filler units 20 may be provided along the bundled drop assembly 10 downstream of a drop location where an optical fiber drop cable 16 or electrical conductor cable 18 drops off of the bundled drop assembly 10. In embodiments, the filler units 20 are lengths of solid polymeric material. In other embodiments, the filler units 20 include a strength yarn extending along the longitudinal axis of the filler unit 20 in which the strength yarn is surrounded by the polymeric material. Further, in embodiments, the polymeric material may be solid or foamed.
As shown in
In certain conventional bundled drop assemblies in which the subunits of the layers were counter-helically laid, twisting of the assembly, especially at small bend radiuses where the twist is concentrated in a short liner section of the assembly, would cause the subunits of one layer to tighten and the subunits of the other layer to loosen. This can cause the layer that loosens to unbundle and bulge out from the nominal diameter of the bundled drop assembly. The bulging subunits can prevent the cable assembly from being pulled through a duct or from being overlashed in an aerial installation. Additionally, the twisting can in certain circumstances be sufficient to cause fiber or conductor failure.
Thus, according to the present disclosure, unidirectionally laying the subunits 12 of each layer 22, 24 can prevent the combination twist tightening/loosening that can lead to bulging or cable failure.
In addition to the length differential between the subunits 12 of the inner and outer layers 22, 24, the bulging of the subunits 12 is also influenced by the cable length over which the twisting is spread. In particular, spreading the twisting over a larger cable length will reduce the bulging of the subunits 12 from the bundled drop assembly 10. Increasing the stiffness of the bundled drop assembly 10 is one way to increase the cable length over which the twist is introduced into the bundled drop assembly 10 because a stiffer bundled drop assembly 10 will have a larger bend diameter than a less stiff bundled drop assembly, leading to larger twist loops into which the cable length is formed.
In the following discussion, several methods of increasing the stiffness of the bundled drop assembly 10 are discussed. Each of these methods may be used alone or in combination with one of the other disclosed methods in order to provide the desired stiffness of the bundled drop assembly 10.
With reference to
Further, in embodiments in which the bundled drop assembly 10 includes electrical conductor cables 18, the stiffness of the bundled drop assembly 10 can be increased by increasing the gauge of the wire conductor 42 or by reducing the number of strands in the wire conductor 42. For example, for a single wire conductor 42, the gauge can be 16 AWG or larger (by “larger,” it is meant that the diameter of the wire conductor is larger, which is a lower AWG number). Further, for a stranded wire conductor 42 of a certain gauge, the number of strands in the wire conductor 42 can be decreased or the stranded wired conductor 42 can be replaced with a single wire conductor 42. In embodiments, the gauge of the stranded wire conductor 42 is at least 12 AWG or larger (by “larger,” it is meant that the diameter of the stranded wire conductor is larger, which is a lower AWG number).
With reference to
In embodiments in which at least one binder 48 is used, the stiffness of the bundled drop assembly 10 can be further increased by increasing the laylength of the subunits 12 of the first layer 22. Conventionally, the laylength of the subunits 12 was configured to be no more than fifteen times the diameter of the pitch circle running through the first layer 22 of subunits 12 (dashed line shown in
Table 1, below, provides example laylengths for bundled drop assemblies 10 based on the diameter of the central member 13, number of subunits 12, and layer 22, 24. The laylengths provided in Table 1 can be considered minimum laylengths if the layer is surrounded by a binder 48.
Referring now to
As mentioned above, any one of these methods may be used alone or in combination with any one of the other methods to increase the stiffness of the bundled drop assembly 10. However, in embodiments, any or all of the methods of increasing the stiffness are used in combination with the unidirectional laying of the subunits 12 of the layers 22, 24. The combination of unidirectional laying of the subunits 12 of each layer 22, 24 and increasing the stiffness of the bundled drop assembly 10 substantially diminishes or eliminates the effects of unwinding and consequent bulging of subunits 12 that would otherwise result during twisting of the bundled drop assembly 10.
Furthermore, the construction of the bundled drop assembly 10 according to the present disclosure has other incidental advantages. For example, because the subunits 12 of each layer 22, 24 are wound in the same direction, they can also be unwound in the same direction, thereby providing easier mid-span access to the first layer 22 of subunits 12. Additionally, the longer laylengths of the subunits 12 of the first layer 22 allow for increased linespeed as the longer laylengths take less time to wind. Further, the multilayer 22, 24 processing can be done in a single pass where the payoff and take-up reels of the central member 13 are twisted to provide unidirectional laying of each layer 22, 24 of subunits 12 around the central member 13 (instead of spinning the subunits around the central member, which would require multiple passes if the layers counter-helically laid).
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, as used herein, the article “a” is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.
It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.
This application is a continuation of International Application No. PCT/US2021/048669 filed Sep. 1, 2021, which claims the benefit of priority to U.S. Provisional Application Ser. No. 63/078,007 filed on Sep. 14, 2020, the content of which is relied upon and incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63078007 | Sep 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2021/048669 | Sep 2021 | US |
| Child | 18119952 | US |
