Abstract:
A coated conduit end with a perceivable demarcation quickly and reliably indicates how far conduit is screwed or inserted into a coated conduit fitting to form a conduit system.

Description:
FIELD 
     This disclosure relates to conduits and, more specifically, to coated electrical conduits. 
     BACKGROUND 
     Conduit and electrical conduit are tubing systems used to protect and route wiring, electrical wiring, communications wiring, and the like. Conduit may be made of metal (including iron, steel, galvanized steel, stainless steel, aluminum, bronze, and brass), plastic polymer, fiber, fired clay, and composite materials. Types of conduit include rigid metal conduit, galvanized rigid conduit, intermediate metal conduit, electrical metallic tubing, aluminum conduit, rigid nonmetallic conduit, electrical nonmetallic tubing, flexible metallic conduit, liquid-tight flexible metal conduit, flexible metallic tubing, and liquid-tight flexible nonmetallic conduit. 
     By way of example, conduit may comprise a metal core which is coated (potentially on both interior and exterior sides) with a corrosion resistant material, such as zinc or polyurethane. Such corrosion resistant material shall be referred to herein as “thin protective coat”. A protective layer, such as polyvinyl chloride (“PVC”) or another plastic or a polymer, may be applied to the exterior of the conduit, such as by coating the metal core (which may have also received a thin protective coat) in PVC. This protective layer is referred to herein as “external coating”. A conduit with an external coating is referred to herein as “coated conduit”. 
     Conduit may be unthreaded or threaded. A typical piece of threaded conduit comprises at least one male threaded end, which male threaded end is suitable to be screwed into a female threaded conduit fitting or box connector. 
     As used herein, “conduit fitting” shall be used to refer to “couplings”, “conduit bodies”, and “box connectors”. Couplings join two pieces of conduit together via threaded or slip connectors, into which the conduit screws or is otherwise inserted and secured. Conduit bodies join two or more pieces of conduit together via threaded or slip connectors and have an access cover to allow access to the interior of the conduit body. The access cover may be disconnected from the conduit body to expose a cavity and allow wiring or the like to be pulled through conduit which is secured to at least one side of the conduit body. When the wiring is pulled through, the access cover may then being re-connected to the conduit body to cover the cavity. Types of conduit bodies include L-shaped bodies (also referred to as “Ells”), T-shaped bodies (“Tees”), C-shaped bodies (“Cees”), and Service Ell bodies (“SLBs”). Box connectors are structures used to secure conduit to a junction box or other electrical box via a threaded connection or a compression fitting (which may be part of the box connector or may involve additional components). In the case of conduit fittings with threaded connectors, the threaded connector is typically a female receptacle which receives the male threaded conduit end. 
     As with conduits, conduit fittings may be coated in PVC or another plastic polymer external coating. Conduit fittings with an external coating shall be referred to herein as “coated conduit fittings”. A coated conduit fitting may comprise a sleeve at the location of the female threaded receptacle in the fitting; conduit, generally coated conduit, fits into the sleeve and may be screwed into or otherwise may be secured to the female receptacle in the coated conduit fitting. The sleeve of a coated conduit fitting generally accommodates the conduit with a tight fit which may require expansion of the sleeve. When external coating is applied to a conduit, the external coating is often applied by a party other than the party who manufactured the conduit. When external coating is applied to a conduit, markings, if any, on the conduit are frequently covered by the external coating. 
     As used herein, a “conduit system” comprises at least one conduit and at least one conduit fitting. 
     Electrical conduit systems are often installed by electricians, service professionals, and construction laborers. The installation is often in difficult to access areas of structures, attics, drop ceilings, false floors, crawl spaces, concrete structures (in which the conduit may be embedded), beams, or in underground locations such as duct banks, utility tunnels, or trenches in the ground. The conduit is often left in place for years and is subject to moisture, corrosive environmental conditions, decay and movement of the surrounding building or environment, plant and animal life, and other disturbances. For these reasons and because the conduit may protect critical infrastructure, care should be taken when conduit is installed. 
     Commonly, and particularly for electrical conduit systems, the conduit system must be inspected by parties such as engineers and building or construction inspectors; inspectors may have professional or governmental obligations to perform a careful inspection and to note deficiencies relative to required or desired objectives. An element in such inspections may be whether, in a conduit system, conduit has been adequately secured into conduit fittings. In the case of coated conduit fittings, the sleeve may obscure the connection site, making it difficult or impossible to tell whether the conduit has been completely screwed or inserted into the conduit fitting. In addition, the cramped, awkward, and often inaccessible or not easily viewed location of the conduit system may further make it difficult to inspect the conduit system. 
     Disclosed is a coated conduit end with a perceivable demarcation which quickly and reliably indicates how far conduit is screwed or inserted into a coated conduit fitting to form a conduit system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side elevation view of a coated conduit with a demarcation. 
         FIG. 1B  is a side elevation view of the coated conduit and demarcation of  FIG. 1A  with a section cut along the centerline of the conduit. 
         FIG. 1C  is an isometric perspective view of a coated conduit with a demarcation. 
         FIG. 2A  is a side elevation view of the coated conduit and demarcation of  FIG. 1A , wherein the coated conduit is secured to a coated conduit fitting. 
         FIG. 2B  is a side elevation view of the coated conduit, demarcation, and coated conduit fitting of  FIG. 2A , with a section cut along the centerline of the coated conduit and conduit fitting. 
         FIG. 2C  is a side elevation view of the conduit fitting of  FIG. 2A , with a section cut along the centerline of the coated conduit fitting to illustrate the sleeves in the coated conduit fitting. 
         FIG. 2D  is an isometric perspective view of the coated conduit and demarcation of  FIG. 1C , wherein the coated conduit is secured to a coated conduit fitting. 
         FIG. 3A  is a side elevation view of a curved coated conduit with a demarcation. 
         FIG. 3B  is a side elevation view of the curved coated conduit and demarcation of  FIG. 3A , with a section cut along the centerline of the curved coated conduit. 
         FIG. 4A  is a side elevation view of the curved coated conduit and demarcation of  FIG. 3A , wherein the curved coated conduit is secured to a coated conduit fitting. 
         FIG. 4B  is a side elevation view of the curved coated conduit, demarcation, and coated conduit fitting of  FIG. 4A , with a section cut along the centerline of the conduit and coated conduit fitting. 
         FIG. 5A  is a side elevation view of a coated conduit with demarcations, wherein the coated conduit is secured to another example of a coated conduit fitting. 
         FIG. 5B  is a side elevation view of the coated conduit with demarcations of  FIG. 5A , without the coated conduit fitting to illustrate how the sleeve of the coated conduit fitting interacts with the demarcations. 
         FIG. 6A  is a side elevation view of a curved coated conduit with demarcations, wherein the curved coated conduit is secured to another example of a coated conduit fitting. 
         FIG. 6B  is a side elevation view of the curved coated conduit and demarcations of  FIG. 6A , without the coated conduit fitting to illustrate how the sleeve of the coated conduit fitting interacts with the demarcations. 
         FIG. 7A  is an perspective view of a conduit with an example of demarcations created through use of labels. 
         FIG. 7B  is an perspective view of the conduit and demarcations of  FIG. 7A , further comprising two coated conduit fittings to illustrate how the coated conduit fittings interact with the demarcations. 
         FIG. 8A  is a side elevation view of a straight coated conduit and a curved coated conduit, both with demarcations, illustrating the coated conduit end which is common to both the straight and curved coated conduits. 
         FIG. 8B  is a close side elevation view of the coated conduit end and demarcation of  FIG. 8A . 
         FIG. 9  is a close isometric parallel projection view of a coated conduit end with a section cut along the centerline of the coated conduit end. 
         FIG. 10  is a close side elevation view of a coated conduit end, illustrating another example of a demarcation. 
         FIG. 11A  is a close side elevation view of a coated conduit end, illustrating another example of a demarcation. 
         FIG. 11B  is a close side elevation view of the coated conduit end of  FIG. 11A , with a section cut along the centerline of the coated conduit end. 
     
    
    
     DETAILED DESCRIPTION 
     The description of the drawings and the following detailed description refer to the accompanying drawings. The same element number in different drawing figures generally identifies the same or similar elements and/or components. Element numbers followed by an “A” or “B” identify substantially similar components (including components which are mirror images of one another), within conventional manufacturing tolerances; when written without the “A” or “B,” the element number shall refer to either such component. If the drawings are viewed one entire page at a time, and if the pages are flipped up or down one entire page at a time, then certain of the Figures are arranged to show components come and go with the page change. 
     This Detailed Description section provides specific details for an understanding of various examples of the technology. One skilled in the art will understand that the technology may be practiced without many of these details. In some instances, structures and functions have not been shown or described in detail or at all to avoid unnecessarily obscuring the description of the examples of the technology. It is intended that the terminology used in the description presented below be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain examples of the technology. Although certain terms may be emphasized below, any terminology intended to be interpreted in any restricted manner will be overtly and specifically defined as such in this Detailed Description section. 
     As used herein, “releasable,” “connect,” “connected,” “connectable,” “disconnect,” “disconnected,” and “disconnectable” refers to two or more structures which may be connected or disconnected, generally without the use of tools (examples of tools including screwdrivers, pliers, drills, saws, welding machines, torches, irons, and other heat sources) and generally in a repeatable manner. As used herein, “attach,” “attached,” or “attachable” refers to two or more structures or components which are attached through the use of tools or chemical or physical bonding. As used herein, “secure,” “secured,” or “securable” refers to two or more structures or components which are either connected or attached. 
     Referring to  FIG. 1A , Coated Conduit  100  comprises Threaded Male Portions  120 A and  120 B. Areas of Coated Conduit  100  which are not threaded are coated with an external coating which may be, for example, PVC or another polymer. Diagonal lines in Sleeve Covered Areas  105 A and  105 B indicate a perceivable demarcation relative to Non-Sleeve Covered Area  115 . The perceivable demarcation may be provided by, for example, different colors or materials applied to or present in the external coating. For example, Sleeve Covered Areas  105 A and  105 B may be a first color, while Non-Sleeve Covered Area  115  is a second color. The perceivable demarcation may be a tactile difference, as may be produced by different materials or a relief pattern in the external coating. A tactile difference may aid in identification of the perceivable demarcation when visual inspection is not possible. An example of a tactile difference is illustrated in  FIGS. 11A and 11B . 
       FIG. 1B  illustrates Coated Conduit  100  with a section cut along the centerline of Coated Conduit  100 . Relative to  FIG. 1A ,  FIG. 1B  further illustrates Core  130  within Coated Conduit  100 . 
       FIG. 2A  illustrates Coated Conduit and Coated Conduit Fitting  200 . In  FIG. 2A , Coated Conduit  100  is secured in Coated Conduit Fitting  135 . Coated Conduit Fitting  135  comprises Sleeves  130 A and  130 B. Sleeve  130 B covers Sleeve Covered Area  105 A, as may be observed by flipping between Drawing Sheet  1  and  2 . Sleeve Covered Area  105 B and Threaded Male Portion  120 B are labeled in  FIG. 2A  for the sake of clarity. 
       FIG. 2B  illustrates Coated Conduit and Coated Conduit Fitting  200 , with a section cut along the centerline of Coated Conduit  100  and Coated Conduit Fitting  135 .  FIG. 2B  further illustrates how Coated Conduit  100  may be screwed into Coated Conduit Fitting  135  and how Sleeve  130 B covers Sleeve Covered Area  105 A. 
       FIG. 2C  is a side elevation view of Coated Conduit Fitting  135 , with a section cut along the centerline of Coated Conduit Fitting  135  to illustrate Sleeves  130 A and  130 B without Coated Conduit  100 . 
       FIG. 1C  is an isometric perspective view of Coated Conduit  100 , provided for the sake of illustrating the 3-dimensional shape of Coated Conduit  100 . 
       FIG. 2D  is an isometric perspective view of Coated Conduit  100  and Coated Conduit Fitting  135 , provided for the sake of illustrating the 3-dimensional shape of Coated Conduit  100  and Coated Conduit Fitting  135 . 
       FIG. 3A  is a side elevation view of Curved Coated Conduit  300 . As with Coated Conduit  100 , Curved Coated Conduit  300  comprises Threaded Male Portions  320 A and  320 B. Areas of Curved Coated Conduit  300  which are not threaded are coated with an external coating. Diagonal lines in Sleeve Covered Areas  305 A and  305 B indicate a perceivable demarcation relative to Non-Sleeve Covered Area  315 , similar to the perceivable demarcation illustrated in  FIG. 1 . 
       FIG. 3B  is a side elevation view of Curved Coated Conduit  300 , with a section cut along the centerline of Curved Coated Conduit  300 . Relative to  FIG. 3A ,  FIG. 3B  further illustrates Core  330  within Curved Coated Conduit  300 . 
       FIG. 4A  illustrates Curved Coated Conduit  300  secured in Coated Conduit Fitting  135 . As in earlier Figures, Coated Conduit Fitting  135  comprises Sleeves  130 A and  130 B. Sleeve  130 B covers Sleeve Covered Area  305 A, as may be observed by flipping between Drawing Sheet  4  and  5 . 
       FIG. 4B  illustrates Curved Coated Conduit  300  secured in Coated Conduit Fitting  135 , with a section cut along the centerline of Curved Coated Conduit  300  and Coated Conduit Fitting  135 .  FIG. 4B  further illustrates how Curved Coated Conduit  300  may be screwed into Coated Conduit Fitting  135  and how Sleeve  130 B covers Sleeve Covered Area  305 A. 
       FIG. 5A  is a side elevation view of Coated Conduit  100 , wherein Coated Conduit  100  is secured to another example of coated conduit fitting, Conduit Body  500 . 
       FIG. 5B  is a side elevation view of Coated Conduit  100 , without Conduit Body  500  to illustrate how the sleeve of Conduit Body  500  interacts with the demarcations of Coated Conduit  100 . 
       FIG. 6A  is a side elevation view of Curved Coated Conduit  300 , wherein Curved Coated Conduit  300  is secured to Conduit Body  500 . 
       FIG. 6B  is a side elevation view of Curved Coated Conduit  300 , without Conduit Body  500  to illustrate how the sleeve of Conduit Body  500  interacts with the demarcations of Curved Coated Conduit  300 . 
       FIG. 7A  is a perspective view of Conduit  700  with an example of demarcations created through use of Labels  705 A and  705 B, which Labels  705  may be applied to an underlying conduit. Labels  705  demarcate a portion of Conduit  700 , Sleeve Covered Portion  715 A and  715 B, which may be covered by a sleeve of a conduit fitting. Label  705  may indicate conformance to a private or public regulatory standard or testing to a certified level, as, for example, may be performed by a Nationally Recognized Testing Laboratory, such as Underwriters Laboratories or the like. 
       FIG. 7B  is a perspective view of Conduit  700  secured to Coated Conduit Fittings  710 A and  710 B, illustrating how Sleeve Covered Portions  715 A and  715 B are covered by the sleeves of Coated Fittings  710 A and  710 B when Conduit  700  is properly secured to Coated Conduit Fittings  710 A and  710 B. 
       FIG. 8A  is a side elevation view of Straight Coated Conduit  100  and Curved Coated Conduit  400 . Straight Coated Conduit  100  comprises Coated Conduit Ends  810 A and  810 B and Central Portion  815 , which in this instance is straight. Curved Coated Conduit  400  comprises Coated Conduit Ends  810 C and  810 D and Central Portion  820 , which in this instance is curved. Coated Conduit Ends  810  comprise a demarcation, as discussed above, between an area of Coated Conduit End  810  which is covered by a coated conduit fitting sleeve and an area of Coated Conduit End  810  which is not covered by a coated conduit fitting sleeve. Lines  830 ,  835  and  840  indicate where Coated Conduit End  810  begins relative to the remainder of the Coated Conduit. As illustrated in  FIG. 8A , Central Portion  815  and  820  may be curved or straight or may comprise another geometry; in any case Coated Conduit Ends  810  are consistent, with the bend radius of Central Portion  820  of Curved Coated Conduit  400  beginning after the ends of Conduit Ends  810 C and  810 D. 
       FIG. 8B  is a close side elevation view of Coated Conduit End  810 . The thickness of external coating is indicated at External Coating  845 . 
       FIG. 9  is a close isometric perspective view of Coated Conduit  100  with a section cut along the centerline, illustrating the 3-dimensional structure of Coated Conduit  100 . 
       FIG. 10  is a close side elevation view of Coated Conduit End  1000 , illustrating an example of a demarcation, in this instance, Circumferential Line  1005 . Circumferential Line  1005  indicates the portion of Coated Conduit End  1000  which is to be covered by a coating fitting sleeve. 
       FIG. 11A  is a close side elevation view of Coated Conduit End  1100 , illustrating another example of a demarcation, in this instance, Raised Circumference  1105 . Raised Circumference  1105  indicates the portion of Coated Conduit End  1100  which is to be covered by a coating fitting sleeve. 
       FIG. 11B  is a close side elevation view of Coated Conduit End  1100 , with a section cut along the centerline of Coated Conduit End  1100 . Relative to  FIG. 11A ,  FIG. 11B  illustrates that Raised Circumference  1105  may be created by a wire, thread, cord, O-ring, O-ring compression clamp, or the like at Tactile Structure  1110 , which may be positioned at the demarcation and then coated with external coating. In the alternative, the wire, thread, cord, O-ring, a whole or broken O-ring compression clamp, or the like, generally in the same location as Tactile Structure  1110 , may be on the exterior of the conduit rather than, as illustrated in  FIG. 11B , beneath exterior coating. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the term “connected,” “coupled,” or any variant thereof means any connection or coupling, either direct or indirect between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof. Additionally, the words, “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to particular portions of this application. When the context permits, words in the description using the singular may also include the plural while words using the plural may also include the singular. The word “or,” in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of one or more of the items in the list. 
     The above detailed description of embodiments is not intended to be exhaustive or to limit the disclosure to the precise form disclosed above. While specific embodiments of and examples for conduit end are described above for illustrative purposes, various equivalent modifications are possible within the scope of the system, as those skilled in the art will recognize.