The present invention is related to cables and, more particularly, to a cable with separable electrical conductors. Standard conductor cables tend to have a large cross section and include multiple separate elements that are independently insulated and stranded. Such typical conductor cables allow for separate elements to be separated due to the independent insulation.
One embodiment of the disclosure relates to a cable including a first copper conductor, a second copper conductor, and an insulation layer formed from a first polymer material. The insulation layer is a single layer surrounding the first copper conductor and the second copper conductor, and is contiguous and continuous circumferentially around the first copper conductor and the second copper conductor for at least 10 cm in a longitudinal direction. A discontinuity, formed from a second polymer material, is located within the insulation layer and positioned between the first copper conductor and the second copper conductor. The discontinuity provides a weakness within the insulation layer. A jacket surrounds the insulation layer, and includes a third polymer material.
An additional embodiment of the disclosure relates to a cable including a first electrical conductor, a second electrical conductor, and an insulation layer formed from a first polymer material. The insulation layer is a single layer surrounding the first electrical conductor and the second electrical conductor, and is contiguous and continuous for at least 10 cm in a longitudinal direction. A discontinuity, formed from a second polymer material, is located within the insulation layer and positioned between the first electrical conductor and the second electrical conductor. The discontinuity provides a weakness within the insulation layer. A jacket surrounds the insulation layer, and includes a third polymer material. An optical fiber ribbon is located within the discontinuity between the first electrical conductor and the second electrical conductor in a radial direction when the cable is viewed in a cross-section taken perpendicular to a longitudinal axis of the cable. The optical fiber ribbon includes a plurality of optical fibers aligned in a plane and embedded in a polymeric ribbon matrix.
An additional embodiment of the disclosure relates to a method of forming a cable. The method includes passing a first copper conductor and a second copper conductor together through an extrusion head. A single contiguous insulation layer is extruded around both the first copper conductor and the second copper conductor. A cable jacket is extruded around the single contiguous insulation layer.
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.
The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:
Referring generally to the figures, embodiments of the present disclosure relate to a cable with separable electrical conductors. In particular, the designs discussed herein include multiple, separate electrical conductors located within a single, contiguous, and continuous insulation layer. In various embodiments, that single insulation layer includes a discontinuity that improves the separability of the electrical conductors from each other, while at the same time providing the processing and size benefits of a single insulation layer. In addition, in some embodiments, the cables discussed herein include a fiber optic ribbon located between the copper conductors.
In certain configurations, Applicant has found that the design discussed herein facilitates small form factor copper or copper-fiber hybrid cables. In particular, Applicant has found that pie-shaped copper conductors in a copper-fiber hybrid cable increases power density of the cable. In some designs, smaller copper conductors also allow for better bending characteristics of the cable for a given power conduction level due to the increased power density of the cable. In specific designs, inclusion of an optical fiber ribbon between pie-shaped copper conductors provides a cable design that allows for delivery of both optical communication functionality and electrical power (e.g., to power wireless networking equipment) in a compact and space-efficient form factor. Further, in specific designs, the relative positioning of optical fibers relative to the conductor elements provides mechanical protection of the optical fiber ribbon.
Furthermore, in various embodiments, Applicant has developed a method for forming such cables utilizing a process in which the common insulation layer of the electrical conductors in the cable is extruded around multiple electrical conductors at the same time and in the same extrusion step (e.g., via extrusion from a single extrusion head). Applicant has found that a method of forming such a cable allows for the electrical conductors to be processed simultaneously in a single pass and incorporate discontinuities, or fast access features, between the electrical conductors. In addition to single pass processing, copper conductor spacing is controlled, and optical fiber ribbons incorporated into the cable design. The discontinuities allow for separation of electrical conductors from each other and/or for fast access to the optical fiber ribbon.
Referring to
Cable 10 includes discontinuity 18 formed from a second polymer material (e.g., that is different from the first material of insulation layer 16) that is located within the insulation layer 16. In general, discontinuity 18 provides for a weakness (i.e. a separability between first copper conductor 12 and second copper conductor 14) within insulation layer 16 that allows for first copper conductor 12 and second copper conductor 14 to be easily separated from each other and routed separately. In the specific embodiment shown, discontinuity 18 is positioned between the first copper conductor 12 and the second copper conductor 14, generally located within a central plane, as shown in
In various embodiments, the first material from which insulation layer 16 is formed includes a variety of thermoplastic materials, such as various polyethylene and polypropylene materials. In various embodiments, the second material of discontinuity 18 is a thermoplastic material different from the material of insulation layer 16, and may include a variety of different thermoplastic materials, such as various polyethylene and polypropylene materials. In various embodiments, insulation layer 16 and/or discontinuity 18 may be formed from polypropylene, polyethylene, blends of polyethylene and ethylene vinyl acetate, engineered polyolefin blends (one example being Apolhya®, a polyamide-grafted polyolefin, polyamid and polyamid blends), flame retardant materials (e.g., flame retardant polyethylene, polyvinylchloride, and polyvinylidene difluoride-filled materials such as polybutylene terephthalate, polycarbonate and/or polyethylene and/or ethylene vinyl acrylate), or other blends having fillers such as a chalk or talc.
Cable 10 includes jacket 20 which surrounds the insulation layer 16. In specific embodiments, jacket 20 is made of a third polymer material, which may be different from at least one of the polymer material of the insulation layer 16 and the polymer material of discontinuity 18. In various embodiments, cable jacket 20 may be made of a variety of materials used in cable manufacturing, such as polyethylene, polyvinyl chloride (PVC), polyvinylidene difluoride (PVDF), nylon, polypropylene, polyester or polycarbonate and their copolymers. In addition, the material of cable jacket 20 may include small quantities of other materials or fillers that provide different properties to cable jacket 20. For example, the material of cable jacket 20 may include materials that provide for coloring, UV/light blocking (e.g., carbon black), fire resistance as discussed above, etc.
In specific embodiments, the polymer material of discontinuity 18 is co-extrudable with the polymer material of insulation layer 16. In various embodiments, a bond strength between the polymer material of discontinuity 18 and the first material of insulation layer 16 is less than an internal bond strength within insulation layer 16 which provides for the weakness/separability as noted above. The discontinuity 18 allows the insulation layer 16 to tear along the discontinuity, which in turn allows the first copper conductor 12 to be separated from the second copper conductor 14.
As shown in
As shown in
In general, the designs of the cables discussed herein utilizing the common insulation layer are believed to allow for higher levels of conductor density and consequently power density than is typically believed to be provided in conductor cables. In specific embodiments, first copper conductor 12 and second copper conductor 14 each includes a plurality of smaller copper conductors 28. In various embodiments, the smaller copper conductors 28 are packed within the insulation layer at a density greater than 80%, for example from 80% to 100% and more specifically between 80% to 90%.
Referring to
Similar to the arrangement in cable 10, in cable 56, discontinuity 18 allows the insulation layer 16 to tear along the discontinuity, which in turn allows the first copper conductor 12 to be separated from the second copper conductor 14. In cable 56, the separation of the first copper conductor 12 from the second copper conductor 14 provides access to the optical fiber ribbon 50. Optical fiber ribbon 50 (or one or more optical fibers of optical fiber ribbon 50) can then be routed as desired to provide optical network communication to one or more devices or users.
Similar to cable 10, cable 56 includes central plane 36 that resides within the discontinuity 18. However, in cable 56, the optical fiber ribbon 50 is supported within cable 56 such that central plane 36 generally aligns with the central ribbon plane. In this arrangement, the polymer material of the insulation layer 16 and/or the polymer material of discontinuity 18 contacts an outermost surface 54 of the optical fiber ribbon 50.
In specific embodiments of both cable 10 (
Referring to
In general, discontinuities 24 and 26 are formed and function the same as discontinuity 18 discussed above. Thus in such embodiments, the second discontinuity 24 allows the insulation layer 16 to tear along the discontinuity 18, which in turn allows the second copper conductor 14 to be separated from the third copper conductor 22. The third discontinuity 26 allows the insulation layer 16 to tear along the discontinuity 18, which in turn allows the first copper conductor 12 to be separated from the third copper conductor 22.
Referring to
In a specific embodiment, cable 70 includes at least one additional layer 34 located between the insulation layer 16 and the jacket 20. In various embodiments, additional layer 34 may be an armor layer, a tensile strength layer (e.g. aramid yarn), and/or a water-blocking layer containing a super-absorbent polymer or water-blocking yarn/tape. However, it is contemplated that other suitable layers and corresponding materials may be used.
In general, discontinuities 24, 26, and 32 are formed and function the same as discontinuity 18 discussed above. Thus in such embodiments, second discontinuity 24 allows the insulation layer 16 to tear along discontinuity 24, which in turn allows the second copper conductor 14 to be separated from the third copper conductor 22. The third discontinuity 26 allows the insulation layer 16 to tear along discontinuity 26, which in turn allows the third copper conductor 22 to be separated from the fourth copper conductor 30. The fourth discontinuity 32 allows the insulation layer 16 to tear along discontinuity 32, which in turn allows the first copper conductor 12 to be separated from the fourth copper conductor 30.
Further, referring to
In specific embodiments, shown in
The optical fibers discussed herein may be flexible, transparent optical fibers made of glass or plastic. The fibers may function as a waveguide to transmit light between the two ends of the optical fiber. Optical fibers may include a transparent core surrounded by a transparent cladding material with a lower index of refraction. Light may be kept in the core by total internal reflection. Glass optical fibers may comprise silica, but some other materials such as fluorozirconate, fluoroaluminate and chalcogenide glasses, as well as crystalline materials such as sapphire, may be used. The light may be guided down the core of the optical fibers by an optical cladding with a lower refractive index that traps light in the core through total internal reflection. The cladding may be coated by a buffer and/or another coating(s) that protects it from moisture and/or physical damage. These coatings may be UV-cured urethane acrylate composite materials applied to the outside of the optical fiber during the drawing process. The coatings may protect the strands of glass fiber.
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/US2021/050014 filed Sep. 13, 2021, which claims the benefit of priority of U.S. Provisional Application Ser. No. 63/082,607 filed on Sep. 24, 2020, the content of which is relied upon and incorporated herein by reference in its entirety.
Number | Date | Country | |
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63082607 | Sep 2020 | US |
Number | Date | Country | |
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Parent | PCT/US2021/050014 | Sep 2021 | US |
Child | 18122821 | US |