The present disclosure relates to optical fiber cables and more particularly to optical fiber cables that have drop cables that run along at least a portion of a central core. Optical fiber cables are used to transmit data over distance. Generally, large distribution cables that carry a multitude of optical fibers from a hub are sub-divided at network nodes, which are further sub-divided, e.g., to the premises of individual subscribers. Generally, these subdivisions involve splicing a cable tether into a main distribution line. Cable splicing at specific locations along a main distribution line is a delicate and time consuming process that requires precise placement of the cable tether and involves the risks of cutting the wrong fibers and providing environmental exposure to the cable interior.
One embodiment of the disclosure relates to an optical fiber carrying structure, such as an optical fiber cable, including a central core, an optical fiber carrying subunit, a connector coupled to an end of the subunit, and a filler rod. The subunit is wound around the central core and extends a first length of the optical fiber cable. The connector is optically coupled to one end of the subunit that extends laterally outward away from the central core. The filler rod is wound around the central core and extends a second portion of the optical fiber cable. The filler rod does not comprise an optical fiber and the filler rod is coupled to an outer surface of the optical fiber carrying subunit.
In another embodiment the disclosure relates to an optical fiber cable including a central core, an optical fiber carrying subunit, a connector and a filler rod. The subunit is wound around the central core and extends a portion of a distance from the first end of the optical fiber cable to the second end of the optical fiber cable. The connector is optically coupled to one end of the subunit that extends laterally outward away from the central core. The filler rod is coupled to the section of the subunit adjacent to the portion that extends away from the central core. The filler rod and the subunit exert a tensile force on each other.
In yet another embodiment the disclosure relates to a method of manufacturing an optical fiber carrying structure that includes unspooling a central core from a first spool and unspooling a first subunit from a second spool. The first subunit includes an optical fiber carrying subunit, a connector and a filler rod. The connector is optically coupled to one end of the subunit that extends laterally outward away from the central core. The filler rod is coupled to the optical fiber carrying subunit. The first subunit is wound around the central core for at least a portion of the length of the central core.
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 optical fiber cable are provided. The bundled optical fiber cable includes a central core, such as an optical fiber carrying structure, and at least one subunit cable wound around the central core. Unlike other cable tethers, one or more of the subunit cables include a pre-connected connector that is spooled into the bundled optical fiber cable during manufacture. In this way connectorized subunit cables can be stranded with connectors at selected locations along the length of the bundled optical fiber. Filler rods are coupled to the subunit cables adjacent to the end of the subunit cable where the connector is coupled. When forming the bundled optical fiber cable, the filler rod exerts a tensile force on the subunit cable. This approach permits the bundled optical fiber cable to be formed easier and more quickly by enabling the connector to be biased away from the central core during spooling of the subunit cable onto the central core. This biasing of the connector away from the central core reduces the likelihood of the connector interfering with the desired formation of the bundled optical fiber cable.
In various embodiments a section of drop cable 14, shown as connection leg 38, extends outwardly from central cable unit 12 at transition point 81 towards connector 66. First end 76 of drop cable 14 is coupled to connector 66 such that connector 66 is in optical communication with one or more optical fibers 20 within drop cable 14.
Filler rod 48 is helically wound around central cable unit 12 and is coupled to the drop cable 14 adjacent to first end 76 of drop cable 14. The drop cable 14 is wound around central cable unit 12 from second end 70 to transition point 81, and filler rod 48 is wound around central cable unit 12 from transition point 81 to first end 68. Thus, drop cable 14 extends a first portion from first end 68 to second end 70 and filler rod 48 extends a second portion from first end 68 to second end 70, so both drop cable 14 and filler rod 48 extend less than the full distance from first end 68 to second end 70. In one embodiment the first portion over which drop cable 14 extends is distinct from the second portion over which filler rod 48 extends. In one embodiment, one or more filler rods 48 extend from first end 68 of bundled optical fiber cable 10 to second end 70 of bundled optical fiber cable 10.
In embodiments, the drop cables 14 are held to the central cable unit 12 only via the winding, which allows the drop cables 14 some degree of movement longitudinally along the length of the central cable unit 12 during bending of the bundled optical fiber cable 10. In embodiments, the laylength of the winding (i.e., the length required for the drop cable 14 to make a complete revolution around the central cable unit 12) is a function of the ratio between the laylength LL and a pitch circle PC (as shown in
In embodiments, bands are placed at various intervals along the length of the bundled optical fiber cable 10 to keep the drop cables 14 wrapped around the central cable unit 12. In certain embodiments, the bands are welded polyethylene bands. In another embodiment, webbing, such as a polyethylene web ribbon, is provided around the drop cables 14 to keep the drop cables 14 wrapped around the central cable unit 12.
As will be appreciated from the discussion provided later herein, in embodiments, the drop cables 14 each have different lengths and run only so far as to reach their desired drop location. The central cable unit 12 spans at least as long as the longest drop cable 14. However, each of the drop cables 14 and the central cable unit 12 has substantially the same beginning point. In an embodiment as shown in
In general, the number of drop cables 14 that can be provided around the central cable unit 12 depends on size of drop cables 14, size of the central cable unit 12, and any external limiting factors for overall size (e.g., a 2″ duct which houses the bundled optical fiber cable 10). In an exemplary embodiment, the central cable unit 12 has an outer diameter of 20 mm, and the drop cables 14 each have an outer diameter d of 4.8 mm. In this exemplary embodiment, fifteen drop cables 14 are able to fit around the central cable unit 12. The outer diameter D of the bundled optical fiber cable 10 according to this exemplary embodiment is approximately 30 mm.
As used herein, the diameter D referenced with respect to the embodiment of
Referring now to the structure of the bundled optical fiber cable 10 as shown in
In an alternate embodiment, the central core of the bundled optical fiber cable does not include any optical fibers 20. Instead the central core comprises a jacket and optionally also comprises one or more strength members.
In embodiments, multiple stacks 21 can be provided in the cable bore 19. In an exemplary embodiment, the cable bore 19 contains six stacks 21 of 288 optical fibers 20 for a total of 1728 optical fibers 20. In another embodiment, the cable bore 19 contains twelve stacks 21 of 288 optical fibers 20 for a total of 3456 optical fibers 20. In embodiments having multiple stacks 21, the stacks 21 may be wound around a central strengthening member, such as a glass-reinforced plastic member. As will be understood, the number of optical fibers 20 provided in the central cable unit 12 has a bearing on the overall size of the bundled optical fiber cable 10. Thus, the number of optical fibers 20 that can be included in the central cable unit 12 may be dictated by the particular installation parameters. Central core of the type described are available from Corning Incorporated, Corning, N.Y., such as those marketed under the trademark RocketRibbon™.
Moreover, while
As can also be seen in the embodiment of
In the embodiment shown in
Referring to
Yarn strands 50 exert a tensile force on filler rod 48 and drop cable 14 when filler rod 48 and drop cable 14 are wound around central cable unit 12. In one embodiment yarn strands 50 communicate a tensile force between drop cable 14 and filler rod 48. The tensile force communicated between filler rod 48 and drop cable 14 facilitates forming bundled optical fiber cable 10 by causing funnel 82 to bias connector 66 away from central cable unit 12 as drop cable 14 and filler rod 48 are being wound around central cable unit 12 (as shown in
Connection leg 38 of drop cable 14 extends away from central cable unit 12 until first end 76 of drop cable 14 is coupled to connector 66. Connector 66 is communicatively coupled to optical fiber 20 within drop cable 14 (e.g., in optical communication with) to facilitate communicatively coupling drop cable 14 to another cable, such as another optical fiber cable. In one embodiment connector 66 has a diameter of 12 mm.
In one embodiment, connection leg 38 is 10 feet for aerial connections, 15 feet for duct connections, and 20 feet for other situations. In another embodiment connection leg 38 is lengthened by severing filler rod 48 from drop cable 14 (e.g., by severing yarn strands 50), and then unwinding drop cable 14 from central cable unit 12 until connection leg 38 is the desired length. In a specific embodiment a band is coupled around the one or more drop cables 14 to prevent the one or more drop cables 14 from unwinding further from central cable unit 12. In various embodiments when connectors 66 coupled to various drop cable 14 are proximate each other, connectors 66 are arranged tip to boot, which is to say that the front of a first connector 66 is proximate the back of the next connector 66.
Turning to
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Drop cable 14 is fed through funnel 82 in direction 88. Sidewalls 98 of funnel 82 define a channel 96 through which drop cable 14 passes. The tensile force within drop cable 14 forces drop cable 14 towards the bottom of funnel 82, as shown from
After drop cable 14 is spooled against central core, connector 66 passes through second opening 86 of funnel 82. Filler rod 48 now spools against central cable unit 12 while connector 66 extends outwardly from central cable unit 12. In one embodiment connector 66 is coupled to filler rod 48 via a connection, shown as stretchable fabric 80.
Turning to
In one embodiment spool 104 is axially rotated so that central cable unit 12 rotates as it approaches closing point 106, whereas drop cables 14 are kept stationary. As a result, drop cables 14 are helically wound around central cable unit 12. In another embodiment spools 102 for drop cables 14 are rotated around central cable unit 12.
At closing point 106, funnel 82 is held in place near central cable unit 12 to permit drop cable 14 to transit into first opening 84 and out of second opening 86. In one embodiment funnel 82 is restrained by a donut that is affixed around sidewalls 98, permitting funnel 82 to axially rotate while drop cable 14 transits funnel 82 towards central cable unit 12. Permitting funnel 82 to rotate allows the tensile force on drop cable 14 to bias funnel 82 so that channel 96 extends towards central cable unit 12. As described above, this positioning of channel 96 helps protect connector 66 from interfering with the placement of drop cable 14 on central cable unit 12.
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/US2020/056798, filed on Oct. 22, 2020, which claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application Ser. No. 62/937,287 filed on Nov. 19, 2019, the content of which is relied upon and incorporated herein by reference in its entirety.
Number | Date | Country | |
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62937287 | Nov 2019 | US |
Number | Date | Country | |
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Parent | PCT/US2020/056798 | Oct 2020 | US |
Child | 17740677 | US |