The present invention relates generally to electrical wire and cable, and more particularly to electrical wire and cable, and methods for manufacturing same, to facilitate their being pulled through structures.
Sheathed cable, particularly non-metallic (“NM”) sheathed cable is suitable for use in concealed or exposed, dry, protected areas, for example, inside stud walls and on the sides of joists, and is commonly used to provide electrical power throughout structures built in the United States. NM cable is installed during the construction phase of a building, home, or other structure by pulling a length of cable from a coil into the structure and through openings or bores formed in the structure's internal framing elements, cutting the cable at its desired length, and connecting the cable to various components, such as outlet boxes, junction boxes, switches, and fixtures.
Conventional NM cable is sold as a single unit in that each coil contains one length of cable (a “circuit”) that has a uniform gauge or size. Consequently, when an electrician needs to install more than one circuit at once, the electrician must pull each circuit from a separate coil. The use of multiple separate coils, particularly when more than one gauge of cable is required, is a significant burden that requires extra set up time and often results in the undesirable entanglement of multiple lengths of cable. By way of example, in a typical home, each room has lighting elements that require one gauge of cable and electrical outlets that require a different gauge of cable. In particular, a 15-amp circuit used for lighting will employ a 14 American Wire Gauge (“AWG”) NM cable, but a 20-amp circuit used for electrical outlets will employ a 12 AWG NM cable. Thus, during construction, a length of 14 AWG NM cable and a length of 12 AWG NM cable will need to be pulled into each room, which conventionally requires the set up and use of more than one coil. As another example, a single room may need more than one dedicated 15-amp circuit, thereby requiring that more than one length of 14 AWG NM cable be pulled into the room.
Disclosed herein are multiple embodiments of a coupled building wire assembly wherein more than one length of cable having the same or different gauges are uniquely coupled together permitting one to pull multiple lengths of cable from a single coil, thereby avoiding many of the disadvantages associated with the prior art. A particular feature of the invention disclosed herein is where such coupled building wire assembly has its exterior surfaces coated with a lubricant to reduce the exterior surface coefficient of friction and thereby reduce required installation pulling forces. As an alternative, the lubricant for the exterior surfaces of the coupled building wire assembly is provided by introducing sufficient lubricant into the outer sheaths during the cables' manufacture that reduces the coefficient of friction of the exterior surface of the coupled building wire assembly.
With reference to
With reference to the embodiment of the coupled building wire assembly 20 illustrated in
In the illustrated embodiment, the first gauge of the at least one circuit conductor 36 of the first length of NM cable 30 is substantially equal to the second gauge of the at least one circuit conductor 46 of the second length of NM cable 40. In other embodiments, the first gauge of the at least one circuit conductor 36 of the first length of NM cable 30 is unequal to the second gauge of the at least one circuit conductor 46 of the second length of NM cable 40.
With continuing reference to the embodiment of
With reference to the embodiment of the coupled building wire assembly 20 illustrated in
With reference to the embodiment illustrated in
With reference to the embodiment illustrated in
Various other means may be used to join cables 30 and 40 together. For example, with reference to
Alternatively, the bottom surface 34 of the first length of NM cable 30 may be coupled to the top surface 42 of the second length of NM cable 40 using a self-locking threaded fastener. In accordance with this embodiment, a self-locking threaded fastener, such as that commonly known by the trademark ZIPLOC®, is attached to the bottom surface 34 of the first length of NM cable 30 and to the top surface 42 of the second length of NM cable 40. The bottom surface 34 of the first length of NM cable 30 and the top surface 42 of the second length of NM cable 40 are then pressed together to lock the self-locking fastener and form the coupled building wire assembly 20. It will be appreciated that the self-locking fastener could be attached during assembly of the coupled building wire assembly 20 or formed into the outer sheath 6 of the first 30 and second 40 lengths of cable by incorporating the self-locking fastener into extrusion tooling.
In still other alternatives, the bottom surface 34 of the first length of NM cable 30 may be removably or permanently coupled to the top surface 42 of the second length of NM cable 40 using any other suitable adhesive material or other means, such as double-sided tape, an adhesive polymeric strip, a binding strip (constructed of mylar, polyester, string or the like), welding (such as hot air welding, ultrasonic welding, solvent bonding or the like), or any combination of the above.
It will be appreciated that each of the aforementioned embodiments allow for easy separation of the first length of NM cable 30 from the second length of NM cable 40 once the coupled building wire assembly has been pulled into the building or home that is under construction. Further, the preferred bonded embodiments offer an inherent tangle-resistance feature thereby reducing and possibly eliminating the problems of multiple cables tangling up during installation. Because the tangling of NM cable is a result of the wire conductors' radii memory, in other words, the tendency to remain coiled and resist straightening, the embodiments disclosed herein eliminate any competing radii memory by providing more than one circuit in the same package and stored with the same radius.
In order to test whether the coupled building wire assembly 20 provided an advantage over conventional single building wire constructions, a test was conducted in which electricians were asked to pull test cables into an eight (8) foot by sixteen (16) foot mock building using an electrical wiring diagram. To establish a baseline, electricians pulled circuits having a single length of NM cable into the mock building according to the diagram, and the time to complete the tasks was recorded. Then, electricians pulled the various embodiments of the coupled building wire assembly 20 described above into the mock building according to the same diagram, and the time to complete the tasks was recorded. Significant time reductions were achieved, in many instances of up to about 60%, over that of pulling only single length NM cable.
In accordance with a unique feature of the various embodiment of the coupled building wire assembly illustrated herein, the exterior surfaces of the sheath 6 (and therefore the outer surface of the coupled building wire assembly) is provided with a lubricating coating to reduce the coefficient of friction of said outer surface to reduce the required pulling forces necessary to install the assembly. In accordance with a first method for providing such lubrication, and by reference to
The lubricant coating 15 may be any suitable substance that provides a thin film on the surface of the coupled building wire assembly 20 to enhance lubricity and lower the coefficient of friction. For example, the lubricant coating 15 may comprise an external release agent manufactured by Axel Plastics Research Laboratories, Inc. and sold under the trade name MoldWiz™. Alternately, the lubricant coating 15 may comprise an aqueous emulsion of resins and at least one surfactant in a water vehicle, or may comprise an emulsion of organic esters, cross-linked polyolefins, fatty acids, and at least one surfactant in a water vehicle. Alternatively, the lubricant coating 15 may comprise a water-and-isopropylalcohol-based dispersion manufactured by E. I. du Pont de Nemours and Company and sold under the trade name DryFilm WDL905, or the lubricant coating 15 may comprise water, at least one siloxane polymer, isopropyl alcohol, and poly-TFE, omega-hydro-alpha-(methylcyclohexyl).
The lubricant may be selected from the group consisting essentially of fatty amides, hydrocarbon oils, fluorinated organic resins, and mixtures thereof. Advantageous fatty amides and metallic fatty acids include, but are not limited to erucamide, oleamide, oleyl palmitamide, stearyl stearamide, stearamide, behenamide, ethylene bisstearamide, ethylene bisoleamide, stearyl erucamide, erucyl stearamide, and the like. Advantageous hydrocarbon oils include, but are not limited to, mineral oil, silicone oil, and the like. Suitable compounds also include plasticizers, dibasic esters, silicones, anti-static amines, organic amines, ethanolamides, mono- and di-glyceride fatty amines, ethoxylated fatty amines, fatty acids, zinc stearate, stearic acids, palmitic acids, calcium stearate, lead stearate, saturated fatty esters, unsaturated fatty esters, and mixtures thereof with and without modified organic acid derivatives, fatty acid amides, amide waxes, stearates, siloxanes, sulfates such as zinc sulfate, and the like. These may be used individually or in combination. Additional suitable lubricants include fluorinated organic resins, such as a polymer of one or more fluorinated monomers selected from the group consisting essentially of tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene and the like. The fluorinated resin may be used in the form of a powder, emulsion or aqueous dispersion.
The lubricant coating 15 may be directly applied to the coupled building wire assembly 20 by various methods, including, but not limited to, dipping the coupled wire assembly 20, or the individual lengths of cable 30 and 40 prior to being coupled, into a container of the lubricant coating 15, spraying one or more surfaces of the coupled wire assembly 20, or of the individual lengths of cable 30 and 40 prior to being coupled, with the lubricant coating 15 using a spray gun or the like, wiping or brushing the lubricant coating 15 onto one or more surfaces of the coupled wire 20, or of the individual lengths of cable 30 and 40 prior to being coupled, or depositing the lubricant coating 15 onto one or more surfaces of the coupled wire assembly 20, or of the individual lengths of cable 30 and 40 prior to being coupled, using a calibrated die or by plasma phase spraying, or with respect to the embodiment illustrated in
According to one process, the spraying step may be carried out between the step of coating the circuit conductor 36 or 46 with plastic material and the step of cooling said material. This position of the spraying step in time is preferred, but not required, since, when the circuit conductor 36 or 46 is coated with the plastic material, said material is in a state of fusion, the high temperature of which causes volatilization of the solvents present in the lubricant coating 15, which means that there is greater adherence of said lubricant coating 15 on the surface of the plastic material. The subsequent cooling of the plastic material together with the lubricant coating 15 leads to drying on the surface, leaving the two materials bonded to form a coating of low coefficient of friction.
The building wire assembly 20 is characterized in that when externally applying the lubricant, if the outer sheath of the cable 30 and/or 40 is somewhat porous, the lubricant coating 15 will reside in the pores of the exterior surface sheath 6. The outer sheath 6 on the cable 30 and/or 40 is thus well covered with said lubricant coating 15, forming a fine layer on the plastic material, since it emerges at high pressure and the plastic material is at high temperatures.
The equipment for the manufacturing of building wire assembly 20 with the externally applied lubricant is characterized as including a device for the application of the lubricant coating 15 on the surface of the cable 30 and/or 40. Said device may be a box section through which the cable 30 or 40 passes, a plurality of nozzles for spraying the lubricant coating 15 mounted inside the box section, a tank for said lubricant coating 15, and a pressure pump to carry the lubricant coating 15 from the tank to the spraying nozzles. Moreover, the device may also include a pressure adjusting valve, a level indicator for the tank containing the lubricant coating 15, and a pressure gauge.
As an alternate process for reducing the coefficient of friction of the surface of the assembly 20, the sheaths 6 may have the lubricant material internally incorporated therein. In accordance with this approach, suitable lubricant material 15 is mixed with the material used to form each outer sheath 6 of cables 30 and 40. The step of mixing the lubricant material 15 and the sheath material may be carried out with the lubricant material 15 heated or not and the sheath material heated or not. The sheath material may be introduced in pellet form to an extruder which heats and directs the sheath material onto the portion of the cable 30 and 40 surrounding circuit conductors 36 and 46. Alternatively, lubricant material 15 may be incorporated into the sheath pellets during their formation and introducing this mixture of sheath pellets and lubricant material 15 into an extruder. Alternatively, the sheath pellets may be introduced into the extruder with the lubricant material 15 subsequently introduced into the extruder prior to contacting the portion of the cable 30 or 40 around circuit conductor 36 or 46. Moreover, it will be appreciated that the lubricant material 15 may be incorporated at any point in the manufacturing process before the formation of the outer sheath 6, and depending upon the material, may be heated prior to mixing with the sheath material. In instances where the sheath material has a high melting or softening temperature, or for other reasons such as processibility, efficiency of the process, etc., the lubricant material 15 may be added to the sheath material as the sheath material is being formed. If the final cable 30 or 40 construction is such that there are two or more different sheaths applied to the circuit conductor 36 or 46, the lubricant material 15 need only be incorporated into the outermost sheath.
The building wire assembly 20 is particularly characterized in that when incorporated in the outer sheath 6 of the individual cables 30 and 40, the lubricant material blooms and migrates toward the exterior surfaces of the cables 30 and 40, or permeates the outer sheath 6, thereby assuring its presence at the exterior surface of the sheath 6. If desired, the sheath material may be somewhat porous thereby resulting in the lubricant material 15 more readily migrating toward the exterior surface of the sheath 6.
The equipment for the manufacturing of building wire assembly 20 according to this “material” process is characterized in that it may include a device for the incorporation of a lubricant material 15 into the sheath material prior to such material's application to the circuit conductor 36 or 46. Said equipment may also include a tank to maintain the lubricant material 15, a section for mixing the lubricant material 15 and sheath material, and a section for applying the mixture to enclose the circuit conductor 36 or 46. Moreover, the equipment may also include a pressure adjusting valve(s), a level indicator(s) for the tank containing the lubricant material 15 and tank containing the sheath material, and a pressure gauge(s).
Lubricant material 15 in sheath 6 provides coupled building wire assembly 20 with a lower coefficient of friction at its outer surface than building wire lacking lubricant material 15 incorporated therein. More particularly, coupled building wire assembly 20 requires significantly less force to pull through a given structure than conventional wire, thereby reducing the installer's level of fatigue, requiring fewer climbs up ladders during installation, and allowing longer pulls of cable during installation. Accordingly, the overall time needed to install the building wire is reduced.
Various additional modifications and changes may be made to the above described embodiments without deporting from the spirit and scope of the invention, as defined by the following claims.
This application is a continuation-in-part application of copending U.S. patent application Ser. No. 11/056,492, filed Feb. 11, 2005, which claims benefit of priority to U.S. provisional application No. 60/544,294, filed Feb. 12, 2004; in combination with copending U.S. patent application Ser. No. 11/055,951, filed Feb. 11, 2005, which claims benefit of priority to U.S. provisional application No. 60/544,294, filed Feb. 12, 2004; in combination with copending U.S. patent application Ser. No. 11/423,193, filed Jun. 9, 2006, which is a continuation of U.S. patent application Ser. No. 10/955,436, filed Sep. 30, 2004, now abandoned, which claims benefit of priority to U.S. provisional application Ser. No. 60/508,148, filed Oct. 1, 2003, and to U.S. provisional application Ser. No. 60/517,851, filed Nov. 6, 2003, all of which are incorporated by reference herein and to which priority is claimed.
Number | Date | Country | |
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60544294 | Feb 2004 | US | |
60544224 | Feb 2004 | US | |
60517851 | Nov 2003 | US | |
60508148 | Oct 2003 | US |
Number | Date | Country | |
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Parent | 11055951 | Feb 2005 | US |
Child | 11056492 | US | |
Parent | 11760344 | Jun 2007 | US |
Child | 11055951 | US | |
Parent | 11423193 | Jun 2006 | US |
Child | 11760344 | US | |
Parent | 10955436 | Sep 2004 | US |
Child | 11423193 | US |
Number | Date | Country | |
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Parent | 11056492 | Feb 2005 | US |
Child | 11967802 | US |