Abstract:
A cable conduit shape holder device, for maintaining the arc of curvature of PVC conduit deployed at corners of building walls during structural construction. The cable conduit shape holder device comprises an arc-shaped, open-sided tubular section having a predetermined length, for externally encapsulating a tubular cable conduit when placed thereon, such that when the section is mounted on a portion of the tubular cable conduit, the section maintains formation of a curved shape in a portion of the tubular cable conduit extending for the predetermined length.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to building and electrical construction materials, including wiring, cable duct, cable ties, cable trays, cable conduit, raceways and PVC conduit for installing wiring in residential and commercial/industrial construction. 
       BACKGROUND OF THE INVENTION 
       [0002]    Electrical systems installed during construction of residential and/or commercial/industrial building require connection of insulated wires which extend between different locations, such as between wall plug-in sockets and circuit breaker panels. Insulated wire may be run in one of several forms of a raceway between electrical devices. This may be a specialized bendable pipe, called a conduit, or one of several varieties of metal (rigid steel or aluminium) or non-metallic polyvinyl chloride (PVC) or high-density polyethylene (HDPE) tubing. Rectangular cross-section metal or PVC wire troughs (North America) or trunking (UK) may be used if many circuits are required. Wires run underground may be run in plastic tubing encased in concrete, but metal elbows may be used at corners of building walls to enable pulling wire around the corners. Wiring in exposed areas, for example factory floors, may be run in cable trays or rectangular raceways having lids. 
         [0003]    A problem with electrical construction occurs when PVC conduit is used during structural layout for providing a path for wiring and the conduit is initially placed at corners of building walls, or at a corner between a vertical building wall and the floor, or the ceiling. In most cases, at a later stage after structural layout, electrical wiring installation is performed by an electrician or other construction workers. As shown in prior art  FIG. 1 a   , during the structural layout or at a later stage, an indentation or niche is formed in the wall for initial placement of the PVC conduit. The PVC conduit is shown with a curvature but will not by itself remain with this shape, since it normally rises and reaches an almost straight profile. Therefore, there is a need to retain the curvature for the wire pulling / wire pushing activity associated with wiring installation. 
         [0004]    Sometimes the wall niche is provided between support frame elements extending vertically, typically made of metal. A hole is usually formed in the vertical support frame element near the floor at the bottom of the support frame element, for receiving the PVC conduit portion extending from the floor. The PVC conduit upper portion is then placed in the niche, and bent at the corner near the floor, and only later in the construction process is the cable pulled through it. 
         [0005]    Typically, the bend or arc of curvature of PVC conduits around the corners of building walls is formed at a tight angle. Sometimes, after having been initially placed at a corner during the structural layout, these conduits are pushed further into the corner during later structural construction by other workmen, such as during flooring installation, plumbing installation, or plasterboard construction. As a result of this pushing, the PVC conduit no longer retains a curvature, and becomes crimped at a sharp angle. There is also the risk of cutting the PVC conduit when it is pushed up against the metal edge in the hole of the support frame element. When the PVC conduit is pushed and crimped or cut as described, it becomes impossible to pull wiring through the PVC conduit around these corners, and also impossible to push wiring ahead through the conduit from an entry point. 
         [0006]    Also, there is the risk of an electrical fault if the PVC conduit is cut and the metal frame element comes into contact with the wiring in the conduit. 
         [0007]      FIG. 1 b    (prior art) illustrates this problem at a building corner with a bent PVC conduit. The bent shape restricts the movement of wiring pushed or pulled through it. 
         [0008]    Sometimes, cement is poured to seal the PVC conduit at the corner of the wall near the floor, and before the cement dries and becomes hardened, it is necessary to retain the shape of the PVC conduit, by using weights to immobilize it. Here again, the formation of a sharp bend or angle in the PVC conduit causes problems. 
         [0009]    Therefore, it would be desirable to provide a solution to the problem of cable conduit crimping and distortion at bends and corners of structural construction. 
       SUMMARY OF THE INVENTION 
       [0010]    Accordingly, it is a principal object of the present invention to overcome the disadvantages associated with the use of PVC conduit during structural construction, where the PVC conduit becomes bent and cannot be used for wiring installation. 
         [0011]    In accordance with a preferred embodiment of the present invention, there is provided a cable conduit shape holder device, for maintaining the arc of curvature of PVC conduit deployed at corners of building walls during structural construction. 
         [0012]    In accordance with a preferred embodiment of the present invention, there is provided a cable conduit shape holder device comprising:
       an arc-shaped, open-sided tubular section having a predetermined length, for externally encapsulating a tubular cable conduit when placed thereon,   such that when said section is mounted on a portion of said tubular cable conduit, said section maintains formation of a curved shape in a portion of said tubular cable conduit extending for said predetermined length.       
 
         [0015]    In an alternative embodiment, there is provided a cable conduit shape holder device comprising:
       an arc-shaped, open-sided tubular fastener having a predetermined length, for externally encapsulating a tubular cable conduit when placed thereon,   said fastener having at least one anchoring point,   such that when a pair of said fasteners are mounted in spaced apart fashion on a portion of said tubular cable conduit, said fasteners are connectable one to another via a connector extending between the anchoring points of each, said connector having a predetermined length so as to maintain formation of a curved shape in the portion of said tubular cable conduit extending between said fasteners.       
 
         [0019]    In this embodiment, the inventive fastener is shaped as a truncated open-sided tube, having an anchoring point formed as an ear extending from an end of said fastener. The ear is formed with a slot enabling a connector such as a tie string or rope or plastic cable tie or other flexible length to be tied at one end to it, with the other end thereof tied to the other fastener, with the connector having a predetermined length so as to insure formation of a curvature in the tubular cable conduit extending between said fasteners. 
         [0020]    Also in a preferred embodiment, each fastener is formed on its interior side with a set of ridges to grip the external side of the cable conduit when mounted thereon. 
         [0021]    An additional feature of the inventive fastener is the provision of an interlock tab on the external side of said fastener to enable it to engage an interlock socket formed on an another fastener, so that two adjacent fasteners may be oriented at a designated angle between them, so that the cable conduits extend at a similar angle. 
         [0022]    The alternative embodiments for the cable conduit shape holder device insure the formation of an arc of curvature in the cable conduit, thereby alleviating the problem of a tight angle or crimped PVC conduit. 
         [0023]    Additional features of the inventive cable conduit shape holder device will become apparent from the following drawings and description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIGS. 1 a - b    are, respectively, perspective views of a prior art PVC cable conduit, shown initially bent at a wall corner, and subsequently shown crimped at a sharp angle, thus restricting easy passage of cable pushed or pulled therethrough; 
           [0025]      FIG. 2  is a perspective view of an embodiment of a cable conduit shape holder device constructed and installed in accordance with the principles of the present invention; 
           [0026]      FIG. 3 a - b    are respectively, front perspective and side views of another cable conduit shape holder device, featuring a pair of fasteners and a connecting brace extending between them; 
           [0027]      FIG. 3 c    shows, respectively, a pair of cable conduit shape holder devices engaging one another at one end thereof, determining their orientation at a designated angle between them; 
           [0028]      FIG. 3 d    is a top end view of the pair of cable conduit shape holder devices shown in  FIG. 3   c;    
           [0029]      FIGS. 3 e - f    show, respectively, end and perspective views of a fastener, showing a detailed view of the interlock tab and socket formed on the fastener sides; 
           [0030]      FIGS. 3 g - h    show, respectively, a pair of cable conduit shape holder devices featuring a pair of fasteners prior to interlocking and after engagement; 
           [0031]      FIG. 4 a    shows a left side perspective view of another embodiment of the inventive cable conduit shape holder device, featuring a pair of fasteners connected by a flexible length extending between them so as to insure formation of a curvature; 
           [0032]      FIG. 4 b    shows a right side perspective view of the fasteners of  FIG. 4   a;    
           [0033]      FIG. 4 c    shows a detailed view of a fastener having an anchoring point for the flexible length; 
           [0034]      FIGS. 4 d - f    show, respectively, side, end and perspective views of the fastener of  FIG. 4 c   ; and 
           [0035]      FIG. 5  shows the inventive cable conduit shape holder device used in an electrical installation, in which cable conduit passes between metal frame elements. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    Referring now to prior art  FIG. 1 a   , as stated in the background, in electrical installations associated with building construction, during structural layout, a PVC conduit  10  is placed in a niche  11  in a wall, with a curvature which will allow passage of a cable to be pushed or drawn therethrough. However, as shown in prior art  FIG. 1 b   , typically, the PVC conduit  10  becomes bent at a corner  13  during later structural construction, and this illustrates a common problem encountered by electricians working at a building wall corner  12 . The bent shape of the PVC conduit  10  at corner  13  restricts the movement of wiring  14  to be pushed or drawn through it. 
         [0037]    Referring now to  FIG. 2 , in accordance with the present invention, there is provided a cable conduit shape holder device  16  which is an arc-shaped, open-sided tubular section having a predetermined length, for externally encapsulating a tubular cable conduit section such as a PVC conduit  10 . The cable conduit shape holder device  16  is shown mounted on a portion of the tubular cable conduit  10 , and thereby insures formation of a curvature in the portion of the tubular cable conduit extending for the predetermined length. This arrangement insures easy passage of the wiring  14 . A rounded edge  23  of device  16  enables slidable insertion of conduit  10  in easy fashion within device  16 , to retain it therein. 
         [0038]    Referring now to  FIG. 3 a   , there is shown a front perspective view of an alternative embodiment of the cable conduit shape holder device  16  of  FIG. 2 . This embodiment is indicated as holder device  16   a , in which a pair of C-shaped clamp-type fasteners  18 ,  20  are provided and attached at the ends of a connecting brace  22  extending between them. The C-shaped clamps each have rounded edges  23  to enable slidable insertion of conduit  10  in easy fashion within the clamp, to retain it therein. The connecting brace  22  is shaped to provide the cable conduit  10  section with a curvature between its ends. Another C-shaped clamp fastener  24  is also provided to hold the connecting brace  22  to the cable conduit  10  at mid-section, to insure the proper curvature of the cable conduit  10  within holder device  16   a.    
         [0039]    A bendable ear  25  formed at the end of clamp  18  provides an anchor point for optional use to fix clamp  18  on a wall. Hole  27  (see  FIG. 3 b   ) also provides this. 
         [0040]    Also shown in  FIG. 3 a    there are formed a pair of interlock sockets  26 ,  28  each attached, respectively, to a side of one of fasteners  18 ,  20 . On the other side of fastener  18  there is formed an interlock tab  30  (visible in  FIG. 3 b   ), and on the other side of fastener  20  there is formed another interlock tab  32  (see  FIG. 3 c   ). Each of the interlock sockets  26 ,  28  is designed to engage a corresponding interlock tab  30 ,  32  when two fasteners are placed adjacent one another (see  FIGS. 3 c - d   ). 
         [0041]    In  FIG. 3 c   , only one section of the device  16   a  length is shown. Although  FIG. 3 c    shows the interlock tab  32  on the left side of clamp  20  on the lower portion of device  16   a , it will be understood that it is possible to use a clamp  18  with the interlock tab  30  on the right side of the clamp  20 , to enable connection of additional sections of device  16   a  length. 
         [0042]    Referring now to  FIG. 3 d   , there are shown, respectively, a pair of adjacent cable conduit shape holder devices  16   a  engaging one another at a pair of fasteners  18  each formed at one end of the holder device  16   a . The engagement of the holder devices  16   a  with one another is enabled by the engagement of interlock tab  30  and interlock socket  26  each respectively formed on one of the holder devices  16   a , and this engagement determines the orientation of holder devices  16   a  at a designated angle “A” between them (see  FIG. 3 c   ). 
         [0043]    In the detailed top end view of  FIG. 3 d   , the engagement of the pair of fasteners  18  in adjacent holder devices  16   a  is shown, which is enabled by engagement of an interlock tab  30  and an interlock socket  26 . The formation of the interlock tab  30  with a star configuration makes it possible to engage interlock socket  26  at different selected angles, which provides holder devices  16  with a large measure of installation flexibility to meet a particular wiring layout and set of construction requirements. 
         [0044]    Referring now to  FIGS. 3 e - f    there are shown, respectively, end and perspective views of a fastener  18  (viewed reverse from  FIG. 3 d   ), showing a detailed view of the interlock tab  30  and interlock socket  26  formed on the sides of fastener  18 .  FIG. 3 e    shows a niche  29  formed in bendable ear  25  to provide flexibility. 
         [0045]    Referring now to  FIGS. 3 g - h    there are shown, respectively, a pair of cable conduit shape holder devices  16   a  featuring a pair of fasteners  18  prior to interlocking and after engagement. In  FIG. 3 g   , the two fasteners  18  are placed adjacent to one another, such that an interlock socket  26  is placed over and above interlock tab  30 . By rotation of one fastener  18  with respect to the other, the orientation between them can be adjusted. The particular angle “A” (see  FIG. 3 c   ) chosen between the fasteners  18  is dependent on this orientation. Once this is established, the fasteners  18  can become engaged and interlocked by downward movement of fastener  18  as illustrated by arrow “B”, as shown. The star configuration of the interlock tab  30  and socket  26  enables the orientation adjustment. 
         [0046]    Referring now to  FIG. 4 a   , there is shown a left side perspective view of another embodiment of the inventive cable conduit shape holder device  16 , indicated here as device  16   b , featuring a pair of fasteners  32  spaced apart and mounted on cable conduit  10 , with the fasteners  32  connected one to the other by a flexible length  34  extending between them so as to insure formation of a curvature in the cable conduit  10 . 
         [0047]      FIG. 4 b    shows a right side perspective view of the holder device  16   b , showing fasteners  32  of  FIG. 4   a.    
         [0048]      FIG. 4 c    shows a detailed view of a fastener  32  having an anchoring point  36  for the flexible length  34 . 
         [0049]    The flexible length  34  may be provided by a plastic strap designed with etched teeth formed along its length. As can be seen in the detailed view of  FIG. 4 c   , the strap is designed to engage fastener  32  at an anchoring point  36  of fastener  32 . A tongue and groove device  38  is formed at anchoring point  36 , such that when the strap end  40  is inserted through the groove, the tongue engages and locks against the teeth formed in the strap  34 . These plastic straps are also known as cable ties, and are used to bundle cables together to form a trunk of individual cables. 
         [0050]    When cement is poured over the PVC conduit and it hardens, the cable ties can be removed. 
         [0051]    Referring now to  FIGS. 4 d - f    there are shown, respectively, side, end and perspective views of fastener  32  of  FIG. 4 a   . Additional features of construction are visible, including rounded edges  23  and /ribs  40  formed within the interior portion of the length of fastener  32 , for providing a better grip on the cable conduit  10 . 
         [0052]    Referring now to  FIG. 5 , there is shown inventive cable conduit shape holder device  16  used in an electrical installation, in which PVC cable conduit  10  passes between metal frame elements  45  which are used to provide structural support. In some installations, the PVC conduit runs from beneath floor tiles  46 , through a hole formed in base frame element  47 . Once it has been re-oriented at the base frame element  47  to bend upwards, the PVC conduit extends through the holes formed in metal frame elements  45 , and is again re-oriented to bend at the hole in wall corner frame element  48 , and then extends to reach the junction box  50  mounted on the wall. 
         [0053]    In the prior art of such electrical installations, where the PVC conduit  10  was directed to bend at a corner, it was subject to cutting by the metal edges of the hole formed in the frame elements  45 ,  47  and  48 . Using the cable conduit shape holder device  16  of the present invention, this is prevented by the thickness of device  16 . 
         [0054]    Where the PVC conduit  10  runs through a metal frame element directly without being bent, the use of a straight portion of cable conduit shape holder device  16  is optional. 
         [0055]    While the present invention has been described with regard to certain specific embodiments thereof, it is to be understood that the description is not meant to be a limitation, as further modifications will now become apparent to those skilled in the art, and it is intended to cover such variations as fall within the scope of protection provided by the appended claims.