Abstract:
An insert bridges a junction box to provide a continuous path between consecutive pipes of an electrical wiring guideway. The insert includes a generally tubular body having a first end and a second end. The insert has a length that is sized to bridge a gap across the junction box and a diameter that is sized for sliding into a pipe of the electrical wiring guideway. A first flange surrounds the generally tubular body and is spaced from the first end thereof. A second flange surrounds the generally tubular body and is spaced from the second end thereof. The flanges abut opposing inner walls of the junction box to ensure that the insert is not lost into a pipe. A slit extends along the length of the insert to allow for removal of the insert once the electrical wiring has been laid.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to the art of installing an electrical service in a building, either as an original installation or as a retrofit.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is common in this industry, when wishing to install an electrical system, to put into place a plurality of junction boxes, along with sections of hollow pipe stretching between adjacent pairs of the junction boxes, and defining essentially a tubular guideway to protect the required electrical wiring.  
           [0003]    In order to install the wiring, a first operation is carried out in which a “fish tape” is fed through the system (the above-mentioned tubular guideway) starting at or adjacent the main electrical panel, and extending to the other end of the guideway. Once the leading end of the fish tape has appeared at the distal end of the guideway (i.e. distal with respect to the electrical panel), it is tied around or connected to the leading end of one or more electrical wires. Then, the fish tape is pulled back in the reversed direction, out of the conduit, simultaneously dragging the wire(s) through the conduit.  
           [0004]    One major problem is that the fish tape, while it is being fed through the guideway, can get caught at one or more of the junction boxes. In view of this, it is standard practice to have an extra employee who moves from junction box to junction box, so that he has access to each junction box as the leading end of the fish tape enters it. The employee at the junction box ensures that the leading end of the fish tape enters the next hollow pipe section so that it can continue on to the next junction box.  
           [0005]    In view of the above, it is an object of the present invention to provide a tool that facilitates the installation of wiring through a tubular guideway.  
         SUMMARY OF THE INVENTION  
         [0006]    According to an aspect of the present invention there is provided an insert for a junction box, the insert comprising:  
           [0007]    a generally tubular body having a first end and a second end, the generally tubular body having a length that is sized to bridge a gap across the junction box and a diameter that is sized for sliding into a pipe of an electrical wiring guideway;  
           [0008]    a first flange and a second flange surrounding said generally tubular body, said first flange being spaced from said first end of said generally tubular body and said second flange being spaced from said second end of said generally tubular body, said first flange and said second flange for abutting opposing inner walls of said junction box; and  
           [0009]    a slit extending along the length of the insert;  
           [0010]    wherein the insert bridges the junction box to provide a continuous path between pipes of the electrical wiring guideway.  
           [0011]    According to another aspect of the present invention there is provided an insert for a junction box that is part of an electrical wiring guideway, the insert comprising:  
           [0012]    a generally tubular body having a first end and a second end, the insert having a length sufficient for bridging a gap across the junction box and a diameter sized for being received inside pipes extending from opposite sides of the junction box to provide a continuous path between the pipes;  
           [0013]    a first flange surrounding the generally tubular body, the first flange being spaced from the first end of the generally tubular body;  
           [0014]    a second flange surrounding the generally tubular body, the second flange being spaced from the second end of the generally tubular body; and  
           [0015]    a slit extending along the length of the insert.  
           [0016]    According to still another aspect of the present invention there is provided an insert comprising:  
           [0017]    a generally tubular body having a first end and a second end, the generally tubular body having a length that is sized to bridge a gap across a manhole and a diameter that is sized for sliding into a pipe of an electrical wiring guideway;  
           [0018]    a first flange surrounding the generally tubular body, the first flange being spaced from the first end of the generally tubular body, the first flange for abutting a pipe opening;  
           [0019]    at least one depressible latch projecting from an outer surface of the generally tubular body, the at least one depressible latch being located adjacent the second end of the generally tubular body; and  
           [0020]    a slit extending along the length of the insert;  
           [0021]    wherein the insert bridges the manhole to provide a continuous path between pipes of the electrical wiring guideway.  
           [0022]    According to another aspect of the present invention there is provided an insert comprising:  
           [0023]    a generally tubular body having a first portion and a second portion, the second portion being received inside the first portion, a length of the generally tubular body being adjustable to bridge a gap across a junction box and a diameter that is sized for sliding into a pipe of an electrical wiring guideway;  
           [0024]    a first flange and a second flange surrounding the generally tubular body, the first flange being spaced from a first end of the generally tubular body and the second flange being spaced from a second end of the generally tubular body, the first flange and the second flange for abutting opposing inner walls of the junction box; and  
           [0025]    a slit extending along the length of the insert;  
           [0026]    wherein the insert bridges the junction box to provide a continuous path between pipes of the electrical wiring guideway.  
           [0027]    The present invention provides advantages in that the insert fits easily into a typical junction box and establishes a guided path along which a leading edge of the fish tape can pass without getting snagged or stuck in any given junction box. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    Several embodiments of this invention are illustrated in the accompanying drawings, in which like numerals denote like parts throughout the several views, and in which:  
         [0029]    [0029]FIG. 1 is a schematic view of a system in accordance with the prior art;  
         [0030]    [0030]FIG. 2 is a view of a portion of the arrangement of FIG. 1, illustrating the problem that arises in the prior art;  
         [0031]    [0031]FIG. 3 is a plan view of an embodiment of the present invention;  
         [0032]    [0032]FIG. 4 is a plan view of another embodiment of the present invention;  
         [0033]    [0033]FIG. 5 is a perspective view of still another embodiment of the invention;  
         [0034]    [0034]FIG. 6 is a perspective view of yet another embodiment of the present invention;  
         [0035]    [0035]FIG. 7 is a perspective view of another embodiment of the present invention;  
         [0036]    [0036]FIG. 8 is a side view of yet another embodiment of the present invention; and  
         [0037]    [0037]FIG. 9 is a side view of another embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0038]    [0038]FIG. 1 illustrates a main electrical panel  10 , representing a standard panel of the kind utilized in residential and office buildings.  
         [0039]    A first section of pipe  12  has an open end  14  and a further end  16  opening into the interior of a first junction box  18 . From the junction box  18 , a further section of pipe  12   a  leads to a second junction box  20 . As can be readily seen in FIG. 1, further sections of pipe  12   b ,  12   c ,  12   d ,  12   e  and  12   f  sequentially connect junction boxes  22 ,  24 ,  26 ,  27  and  28 , defining the aforesaid tubular guideway. The pipe section  12   f  opens into the interior of the junction box  28 , in such a manner that a fish tape  11  can be pulled from a fish tape spool  13  through the installation and attached to one end  30  of one or more spools of wire, identified in FIG. 1 by the numeral  32 . Thus allows the person standing adjacent the opposite end of the fish tape (near the main panel  10 ) to pull the fish tape out of the tubular guideway in the direction opposite the “infeed” direction. This will automatically pull the wire  31  into and through the various pipe sections, eventually making it available adjacent the main electrical panel  10 , where it can be hooked up as desired.  
         [0040]    Attention is now directed to FIG. 2, which illustrates what can happen to a fish tape  11  when entering a junction box such as that marked  34 . Note that the fish tape  11  has entered the junction box  34  at a slight angle (due to its own weight or due to an inherent “springiness” in the fish tape). Whatever the cause, the condition shown in FIG. 2 often arises, namely that the leading end  11  a does not automatically “find” the outlet opening from the junction box, here illustrated at the numeral  36 .  
         [0041]    Attention is now directed to FIG. 3, which illustrates one embodiment of this invention. In FIG. 3, a tubular insert  40  is provided, having a first end  42  adapted to enter the interior of a first pipe section  43  communicating with the junction box  41 , and an opposite end  45  adapted to enter a second pipe section  48 . The tubular insert  40  has a longitudinal slit  50  and a central grip tab  52 , useful for removing the tubular insert  40 . The longitudinal slit  50  is provided so that the insert  40  may be removed after the wires have been fed through the junction box  41 . Two annular flanges  54  and  56  are located adjacent the first and opposite ends  42  and  45 . The annular flanges  54  and  56  serve the purpose of preventing the tubular insert  40  from becoming lost down one of the pipe sections  43 ,  48 .  
         [0042]    [0042]FIG. 4 shows a different selection for the inlet and outlet locations in a junction box  57 , namely locations that are at right angles with respect to each other. Also drawn in FIG. 4 is a tubular insert  60  that is generally elbow shaped, which provides a smooth, rounded inner surface ensuring that the fish tape reaches the required outlet conduit, without becoming jammed.  
         [0043]    The embodiment illustrated in FIG. 5 is preferably a formed unit (as by injection molding, etc.) which has two arms  62  and  64  at generally right angles, joined at a vertex  66  which defines a smoothly curved wall  68  on the inside, the effect of which is to allow the end  11  of the fish tape to pass around to the exit opening in the junction box.  
         [0044]    In FIG. 5, a plastic bracket  70  is provided to hold the insert in place within the junction box.  
         [0045]    The embodiment shown in FIG. 6 includes an elongate tubular portion  72  having integral collars  74 ,  75  to prevent loss of the insert along one of the pipe sections connected to the junction box, and an accordionated central region  77  allowing the insert to flex about the central region. The item also includes a pull tab  78  for easy removal once the fish tape has been inserted.  
         [0046]    In FIG. 7 is shown an embodiment having an elongated tubular portion  82 , a central pull tab  84 , annular flanges  86 ,  87 , and an optional flex location  90  adjacent one end.  
         [0047]    A further option is to provide an extendable and retractable twist lock adjacent the central region. The cut on the twist lock section lines up with a cut on the rest of the insert when “unlocked” for removal. Preferably, the ends would flare out slightly, to ensure a tight fit inside the conduit.  
         [0048]    The inserts could be made available in different sizes to accommodate all conduit and box sizes. For example, a single insert may work well with ½″ or ¾″ conduit, while the next size up would work with 1″ and 1¼″ conduit.  
         [0049]    Referring to FIG. 8, an insert  100  for use in a manhole  120  is shown. The insert  100  includes a generally tubular body  101 , a first end  102  that is received in a first pipe  106  and a second end  104  that is received in a second pipe  108 . A flange  110  is located adjacent the second end  104  to abut an inner wall  122  of the manhole  120 . The flange  110  ensures that the insert is not lost into the second pipe  108 . A slit  112  extends along the length of the insert  100  for allowing removal once the wiring has been fed between the first pipe  106  and the second pipe  108 . A series of depressible latches  114  project through holes  116  provided in an outer surface of the generally tubular body  101 . Springs (not shown) bias the latches  114  so that they extend outwardly from the outer surface of the insert  100 .  
         [0050]    The insert  100  may be used for facilitating all types of underground wiring, such as fibre optics, for example.  
         [0051]    In use, the first end  102  of the insert  100  is fed into the first pipe  106  by depressing the depressible latches  114 . Once a sufficient length of the insert  100  has been fed into the first pipe  106  and the insert  100  has cleared the second pipe  108 , the insert  100  is retracted from the first pipe  102  and fed into the second pipe  108 . The insert  100  is fed into the second pipe  108  until the flange  110  abuts a pipe opening of the second pipe  108 . The latches  114  that are not depressed inside the first pipe  106  serve to maintain the insert  100  in a proper position so by abutting a pipe opening of the first pipe  106 . Thus, the insert  100  is located between the first and second pipes  106 , 108  in preparation for receiving the fish tape (not shown).  
         [0052]    It will be appreciated that an insert  100  of the type shown in FIG. 8 may also be used in a junction box of an in-house application. The insert  100  would have to be sized to fit the smaller application.  
         [0053]    Referring to FIG. 9, an insert  130  for bridging a junction box  128  is shown. The insert  130  includes a first portion  132  and a second portion  134 . The first and second portions  132 , 134  are generally tubular in shape. The first portion  132  includes a first end  136  that is received in a first pipe  138  and a second end  140  that mates with a first end  142  of the second portion  134 . A second end  144  of the second portion  134  is received in a second pipe  146 . As shown, the second portion  134  has a slightly smaller diameter than the first portion  132  to allow the second portion  134  to slide into the first portion  132 .  
         [0054]    A First flange  148  is located adjacent the first end  136  of the first portion  132  and a second flange  150  is located adjacent the second end  144  of the second portion  134 . The flanges  148 ,  150  abut an inner wall  152  of the junction box  128  and ensure that the insert  130  is not lost into either of the pipes  138 , 146 . A slit  154  extends along the length of the insert  130  to allow for removal thereof once the wiring has been fed between the first pipe  138  and the second pipe  146 .  
         [0055]    A depressible latch  156  projects through an aperture  158  provided in an outer surface of the second portion  134 . A spring (not shown) biases the latch  156  outwardly so that it may be received in one of the apertures  160  provided in the first portion  132  of the insert  130 . This allows the length of the insert  130  to be adjusted.  
         [0056]    The inserts are typically comprised of plastic, however, may also be comprised of a metal, such as aluminum.  
         [0057]    In view of the foregoing, it will be seen that there has been provided inexpensive and re-useable tear-away plastic inserts-for location in each junction box at the time the box is mounted along with the pipe sections. The insert is designed to allow the fish tape to pass through junction boxes without the need for a second worker to feed the fish tape through each junction box, especially when these are mounted on high ceilings. Embodiments have been described which allow the fish tape to pass through straight runs, 90° turns or other angulations (for example 45°). The inserts are simply removed at a later point when fixtures are installed, or when the boxes are closed by attaching the standard covers.  
         [0058]    While several embodiments of this invention have been illustrated in the accompanying drawings and described hereinabove, it will be evident to those skilled in the art that changes and modifications may be made therein without departing from the essence of this invention.