Patent Grant
10978221
Some embodiments of the present invention relate generally to electric wires and cords, including those used for strings of electric lights, and more particularly, to strings of electric lights used for Christmas decorations.
During the Christmas season, strings of electric lights are frequently used for decoration. These strings of electric lights can be subjected to various forces and environmental conditions that can degrade a typical wire. For example, the strings of electric lights may be suspended from rooflines, wrapped around trees, or affixed to other decorative objects. When used for these purposes, electric light strings can be subjected to tensile forces carried in part by the wires in the electric light strings. For this reason, in some cases, it can be desirable or required for the wires to meet certain tensile strength requirements. For example, light strings may be pulled taut while being attached to a roofline. Light strings may also be used to suspend other objects, such as Christmas decorations. Because electric light strings carry electricity, electric light strings need to be able to withstand forces in tension without failing. If a string fails, a customer may be disappointed by the broken light string and may be reluctant to buy that brand of light string in the future. Further, if a string fails, injury can occur due to falling objects or exposure of electric wiring. Wiring used in electric light strings can also be required to meet certain regulatory standards for mechanical or electrical performance to ensure consumer safety. For example, wiring in electric light strings can be required to meet UL standards in the United States. Some of these standards may relate to tensile strength, flammability, melting points, and cold temperature bending, for example.
Electric light strings can comprise a plurality of lamp assemblies connected by one or more wires, and an electrical connector or power plug. Wiring used in strings of electric lights can include an electrical conductor surrounded by an insulator jacket. The electrical conductor can comprise multiple strands of conductive material, such as copper. For example, an ordinary string of incandescent lights can be constructed using #22 AWG wire that contains 16 individual copper strands, and is covered by an insulator jacket made of plastic, such as polyvinyl chloride (PVC).
One way to increase the tensile strength of a wire is to use a thicker wire, such as #20 AWG wiring, or thicker. By doing so, the additional conductive strands or thicker conductive strands can increase the mechanical strength of the wire. However, the conductive materials used in conductive strands are sometimes too expensive for such an approach to be cost effective. For example, common conductors such as copper or aluminum are commodity materials that can be very expensive. Alternatively, multiple wires can be used to connect lamp assemblies. In some electric light strings, twisted pairs of wires are used to increase the tensile strength of the wire. As with the use of thicker wire, this approach can also sometimes be too expensive.
What is needed, therefore, is a reinforced wire that provides improved tensile strength to prevent breakage and that can be manufactured at relatively low cost. Some embodiments of the present invention address this need as well as other needs that will become apparent upon reading the description below in conjunction with the drawings.
Aspects of the present invention relate to reinforced electric wires, particularly reinforced electric wires as used in holiday lighting such as Christmas light strings. In some embodiments, an electric wire is reinforced with a reinforcing string, which is disposed inside an insulator jacket, and generally parallel to the conductors in the wire. By using a reinforcing string made of a material with a high tensile strength and low cost, the overall tensile strength of the wire can be improved while keeping the cost of manufacturing low.
Some aspects of the present disclosure relate to a reinforced electric wire for use in holiday lighting, the wire comprising a plurality of conductor strands, a plurality of reinforcing threads intermixed with the conductor strands, and an insulator jacket. In some embodiments, the reinforcing threads are not twisted with the conductor strands. In some embodiments, the reinforcing threads are twisted with the conductor strands. In some embodiments, the plurality of reinforcing threads and the plurality of conductor strands form a helical shape within the insulator jacket. In some embodiments, the conductor strands are not substantially wrapped around the reinforcing threads, and the reinforcing threads are not substantially wrapped around the conductor strands. In some embodiments, the channels are separated by insulation material along the entire length of the insulator jacket. In some embodiments, the at least two outer channels are either rotationally symmetric about an axis passing through the center channel or reflectionally symmetric about a plane which intersects an axis passing through the center channel. In some embodiments, the reinforcing strands passing through a first outer channel of the at least two outer channels has a higher tensile strength than the reinforcing strands passing through a second outer channel of the at least two outer channels. In some embodiments, twisting the reinforcing strand and the conductor strands creates a bare electric wire with the reinforcing strands and the conductor strands randomly intermixed.
Some aspects of the present disclosure relate to a method for manufacturing a reinforced electric wire for use in holiday lighting, comprising feeding a first conductor strand through a first hole in an orientation plate of a twisting machine, feeding a reinforcing strand through a second hole in the orientation plate of the twisting machine, wherein the second hole is not coaxial with a twisting axis of the twisting machine, feeding a second conductor strand through a third hole the orientation plate of the twisting machine, wherein the third hole is not coaxial with the twisting axis of the twisting machine, and twisting the reinforcing strand and the conductor strands to create a bare electric wire comprising the reinforcing strand and the conductor strands. In some embodiments, the first hole is a center hole of the orientation plate and is coaxial with the twisting axis of the twisting machine. In some embodiments, the second hole is disposed radially between the first hole and the third hole. In some embodiments, the reinforcing string comprises a polymeric fibrous yarn. In some embodiments, the reinforcing string comprises a conductive material having a higher resistivity than the conductor. In some embodiments, the reinforcing string is made of a material selected from the group consisting of nylon, polyester, polypropylene, rayon, Poly-paraphenylene terephthalamide, or mixtures thereof.
Some aspects of the present disclosure relate to a light string comprising a first wire comprising a first plurality of conductor strands, a first plurality of reinforcing threads intermixed with the first plurality of conductor strands, and an first insulator jacket, a second wire comprising a second plurality of conductor strands, a second plurality of reinforcing threads intermixed with the second plurality of conductor strands, and a second insulator jacket, a lamp assembly electrically connected to the first wire and the second wire. In some embodiments, the first plurality of reinforcing threads are randomly intermixed with the first plurality of conductor strands. In some embodiments, the second plurality of reinforcing threads are randomly intermixed with the second plurality of conductor strands.
The foregoing summarizes only a few aspects of the present invention and is not intended to be reflective of the full scope of the present invention. Additional features and advantages of the present invention are set forth in the following detailed description and drawings, may be apparent from the detailed description and drawings, or may be learned by practicing the present invention. Moreover, both the foregoing summary and following detailed description are exemplary and explanatory and are intended to provide further explanation of the presently disclosed invention as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate multiple embodiments of the presently disclosed subject matter and serve to explain the principles of the presently disclosed subject matter. The drawings are not intended to limit the scope of the presently disclosed subject matter in any manner.
Aspects of the disclosed technology relate to reinforced wires, and more particularly to reinforced wires for use in holiday electric lighting strings. In some embodiments, an electric wire is reinforced with a reinforcing string or reinforcing thread, which can be disposed inside an insulator jacket, and generally parallel to the conductors in the wire. By using a reinforcing string made of a material with a high tensile strength and low cost, the overall tensile strength of the wire can be improved while keeping the cost of manufacturing low.
Although preferred embodiments of the invention are explained in detail, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the invention is limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the preferred embodiments, specific terminology will be resorted to for the sake of clarity.
It should also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. References to a composition containing “a” constituent is intended to include other constituents in addition to the one named.
Also, in describing the preferred embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
Ranges may be expressed herein as from “about” or “approximately” or “substantially” one particular value and/or to “about” or “approximately” or “substantially” another particular value. When such a range is expressed, other exemplary embodiments include from the one particular value and/or to the other particular value.
Herein, the use of terms such as “having,” “has,” “including,” or “includes” are open-ended and are intended to have the same meaning as terms such as “comprising” or “comprises” and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as “can” or “may” are intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.
It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Moreover, although the term “step” may be used herein to connote different aspects of methods employed, the term should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly required.
The components described hereinafter as making up various elements of the invention are intended to be illustrative and not restrictive. Many suitable components that would perform the same or similar functions as the components described herein are intended to be embraced within the scope of the invention. Such other components not described herein can include, but are not limited to, for example, similar components that are developed after development of the presently disclosed subject matter.
To facilitate an understanding of the principles and features of the invention, various illustrative embodiments are explained below. In particular, the presently disclosed subject matter is described in the context of electric light strings. The present invention, however, is not so limited, and can be applicable in other contexts. For example and not limitation, some embodiments of the present invention may improve electric wiring used in consumer and industrial environments, or any context where improved mechanical strength is beneficial. These embodiments are contemplated within the scope of the present invention. Accordingly, when the present invention is described in the context of decorative electric light strings, it will be understood that other embodiments can take the place of those referred to.
The present disclosure relates to reinforced wires and cords used for carrying electric current. Some embodiments are particularly suited for use in holiday lighting applications, such as electric light strings.
In some embodiments, a reinforced wire comprises at least three components—a conductor, a reinforcing string, and an insulator jacket. The conductor primarily carries an electric current across the length of the reinforced wire, although it may contribute to the tensile strength of the reinforced wire as well. The reinforcing string primarily enhances the tensile strength of the reinforced wire. In some embodiments, the reinforcing string can be an insulating material. In some embodiments, the reinforcing string can be at least partially conductive, and thus may contribute to carrying an electric current. The reinforced wire can comprise one or more reinforcing strings, as may be required in particular applications for various reasons, such as increasing tensile strength. The insulator jacket primarily protects the wire from, for example and not limitation, corrosion and shorts, and helps to prevent electric shocks, although the insulator jacket may also contribute to the tensile strength of the wire.
Some aspects of the present invention may also include electric wires where the conductor is a single conductive strand, or a plurality of conductive strands. As would be recognized by persons having ordinary skill in the art, the selection of a wire having a single conductor strand or a plurality of conductive strands is based at least on the desired mechanical properties—such as resistance to, or resilience under bending forces—or desired electrical properties—such as selecting a current carrying capacity suitable for the intended application of the wire. Whether a single or a plurality of conductive strands is selected, the methods and systems for reinforcing the wire are generally the same, as would be recognized by a person of ordinary skill in the art.
As will be understood by those of skill in the art, some aspects of the present invention relate to electric wires, or electric cords. Electric wires are elongate conductors with a single conductive path—all conductor strands are in electrical communication with each other over the length of the wire. This is in contrast with electric cords, which are elongate conductors with at least two conductive paths, each conductive path not in electrical communication with each other over the length of the cord. It should be noted that “electrical communication” as used herein to describe conductor strands within a wire or cord does not refer to electrical communication through a resistive load separate from the conductor or conductors that form a part of the wire or cord (including any conductive reinforcing string or strings), such as a lamp or other device for receiving electric power or electric signals. While some aspects of the present disclosure relate to electric wires, persons having ordinary skill in the art will recognize that the reinforcement systems discussed herein could likewise be applied to electric cords.
Some aspects of the presently disclosed technology include embodiments where a plurality of conductor strands 201 is twisted to form the conductor. In some of these embodiments, the reinforcing string 202 is twisted with the conductor strands 201, such as on a twisting machine. In some of these embodiments, the reinforcing string 202 is placed in parallel to the conductor strands 201, and not twisted. For example, a twisted bundle of conductor strands 201 may be co-extruded through an insulating machine with the reinforcing string 202 to create a reinforced wire. Further, in some embodiments, neither the plurality of electric conductors 201 nor the reinforcing string 202 are twisted. Instead, all are substantially parallel along the length of the reinforced wire.
In some embodiments, the reinforcing strands may be substantially surrounded by conductive strands, or may be commingled together within the insulator jacket 203. In some embodiments, the reinforcing threads 901 and conductor strands 201 are twisted together. In some embodiments, the reinforcing threads 901 are substantially parallel to the conductor strands 201, or are not twisted around, within, or with the conductor strands 201. In some embodiments, the reinforcing threads 901 and conductor strands 201 are twisted together. In these embodiments, the reinforcing threads 901 and conductor strands 201 each form a helical shape within the insulator jacket. Further, in these embodiments, the conductor strands 201 are not substantially wrapped around the reinforcing threads 901, nor are the reinforcing threads 901 substantially wrapped around the conductor strands 201.
In some embodiments, the bare electric wire is coated with an insulator jacket (e.g., insulator jacket 203) using an extrusion machine. Extrusion machines typically consist of an insulation material feed system, a heater, and a die or mold for the extrusion process.
Some embodiments of the present invention can be manufactured using equipment ordinarily used for producing stranded electric wiring. Such equipment typically comprises a plurality of spools of wire strands, such as narrow-gauge copper filaments. Each of these spools is located on a spindle, and the strands on each spool are drawn through a hole in an orientation plate 1200 connected to the spindle, as shown in
Embodiments of the present disclosed technology can be made of a variety of materials, as would be understood by one having ordinary skill in the art. Some embodiments may be made of specific materials, as indicated herein, however other materials are also contemplated.
In some embodiments, the conductor strands 201 are made of copper. In some embodiments, the conductor strands 201 are made of aluminum or steel. In one non-limiting example, the plurality of conductor strands 201 can comprise sixteen (16) copper strands. In some embodiments, a conductor strand 201 can provide a portion of the tensile strength of the overall wire. In some embodiments having a plurality of conductor strands 201, all conductor strands 201 are in electrical communication with all other conductor strands 201.
In some embodiments, the reinforcing string 202 can be made of nylon, polyester, polypropylene, rayon, Poly-paraphenylene terephthalamide (marketed as Kevlar®), or mixtures thereof. In some embodiments, the reinforcing string 202 can be made of any polymeric fibrous yarn known in the art, or mixtures thereof. In some embodiments the reinforcing string 202 can be a yarn, such as a flat continuous filament yarn. In some embodiments, the reinforcing string 202 can comprise a plurality of reinforcing threads made of a similar material. In some embodiments the reinforcing string 202 can comprise steel strands, or copper clad steel wire. In some embodiments, the reinforcing string 202 can be made of a metallic material. In some embodiments, the reinforcing string 202 comprises a single filament. In some embodiments, the reinforcing string 202 comprises a plurality of filaments.
In some embodiments, the reinforcing string 202 is non-conductive. In some embodiments, the reinforcing string 202 can be conductive. Where the reinforcing string 202 is conductive, the reinforcing string 202 carries less amperage than all conductor strands present within the wire. This can be, for example, because the conductive reinforcing strand 202 has a higher resistivity than the conductor strands 201. This higher resistivity can be caused by using a material for the reinforcing string 202 with a lower material conductivity, or by electrically insulating the reinforcing string 202 from the conductor strands 201. This electrical insulating may be done by, for example, oxidizing the reinforcing string, or coating the reinforcing string with an insulator material.
In some embodiments, a reinforced wire can be coated in an insulator jacket 203. The insulator jacket 203 can surround the conductor and reinforcing string. The insulator jacket 203 serves to prevent shorting, and permit safe use of the reinforced wire in, for example, holiday lighting applications. The insulator jacket 203 can comprise any material known and used in the art for wire insulation. In some embodiments, the insulator jacket 203 can be made of polyvinyl chloride (PVC). In some embodiments, the insulator jacket 203 can be made of a plastic, such as PVC, semi-rigid PVC, plenum PVC, polyethylene, polypropylene, polyurethane, chlorinated polyethylene, Nylon, and mixtures thereof. In some embodiments, the insulator jacket 203 can be made of a rubber, such as thermoplastic rubber, polychloroprene (Neoprene), styrene butadiene rubber, silicone, fiberglass, ethylene propylene rubber, rubber, chlorosulfonated polyethylene, ethylene propylene diene monomer, and mixtures thereof. In some embodiments, the insulator jacket 203 can be made of a fluoropolymer, such as PFA, polytetraflouroethylene, fluorinated ethylene propylene, ETFE Tefzel and ECTFA Halar, polyvinylidene fluoride, thermoplastic elastomers, and mixtures thereof. In some embodiments, the insulator jacket 203 can be made of a mixture of a plastic, rubber, or fluoropolymer as described above, and one or more plasticizers, stabilizers, mineral fillers, lubricants, and other additives as is known in the art.
While the present disclosure has been described in connection with a plurality of exemplary aspects, as illustrated in the various figures and discussed above, it is understood that other similar aspects can be used or modifications and additions can be made to the described aspects for performing the same function of the present disclosure without deviating therefrom. For example, in various aspects of the disclosure, methods and compositions were described according to aspects of the presently disclosed subject matter. However, other equivalent methods or composition to these described aspects are also contemplated by the teachings herein. Therefore, the present disclosure should not be limited to any single aspect, but rather construed in breadth and scope in accordance with the appended claims.
The present application is a continuation of and claims priority under 35 U.S.C. 120 to U.S. patent application Ser. No. 16/669,991, which was filed on Oct. 31, 2019 which claims priority under 35 U.S.C. 120 to U.S. patent application Ser. No. 15/273,037, which was filed on Sep. 22, 2016 which claims the benefit of U.S. Provisional Patent Application No. 62/272,812, which was filed on Dec. 30, 2015. The entire contents and substance of each of these applications are hereby incorporated by reference in their entirety as if fully set forth herein.
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| Number | Date | Country | |
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| 20200388416 A1 | Dec 2020 | US |
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 16669991 | Oct 2019 | US |
| Child | 17000821 | US | |
| Parent | 15273037 | Sep 2016 | US |
| Child | 16669991 | US |
