Abstract:
The embodiments provide a barb assembly for use with a cable duct component to oppose removal of a cable duct section from the cable duct component. The barb assembly and/or cable duct component can comprise one or more barb arm supports, which can increase the ability of the barb assembly to oppose removal of the cable duct section from the cable duct component. The embodiments also provide methods of installing cable duct components and systems with the above-described features.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application 60/513,121, filed Oct. 21, 2003, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to the field of duct-type cable routing systems. More specifically, the invention relates to fittings that include barb assemblies that can bitingly engage an end of a cable duct section and oppose removal of the cable duct section from the cable duct component. 
     2. Background 
     Raceway duct systems have become very popular in recent years to route, protect, and conceal data, voice, video, fiber optic, and/or power cabling. Such systems allow custom installation and can be provided within walls or provided on external surfaces, allowing ready access for reconfiguration, repair, or installation of additional equipment. Such systems may typically include various sections of duct or raceway, including straight sections and various fittings, such as 90° elbow fittings, 45° elbow fittings, T-fittings, four-way intersection (x) fittings, and the like, respective ones of which are affixed together by duct couplers to cumulatively form a duct system. 
     U.S. Pat. Nos. 6,634,605, 6,523,791, 6,450,458, and 6,559,378 provide examples and descriptions of the general background of cable duct couplers and other cable duct fittings, and the entirety of these applications are incorporated herein by reference as though set forth here in full. U.S. Pat. No. 5,316,243 (assigned to ADC Telecommunications, Inc.) provides a description of the general background and environment of cable routing systems, and the specification of that issued patent is incorporated herein by reference as though set forth here in full. 
     Due to the increase in the number and sophistication of such raceway duct systems, the number of duct couplers and fittings being installed in such systems has also increased significantly. Therefore, it is important to have couplers and fittings that are easy to install and inexpensive to manufacture, and that provide relatively high resistance to “pullout” forces to prevent unintended disassembly. 
     Previous designs disclosed cable duct components with barb assemblies that could bitingly engage another component of a cable duct system, such as a section of cable duct or raceway. Through such engagement, the barb could resist a tensile “pullout” force applied to the other cable duct component, and the barb could oppose removal of that component. There are limits, however, to the pullout force that the barb can resist. Although previous designs were improvements over the prior art, it would be a further improvement to provide a product that could resist a larger pullout force. Significantly, the present invention increases the ability of a barb to resist a tensile pullout force. 
     SUMMARY 
     In one embodiment, there is provided a barb assembly for use with a cable duct component to oppose removal of a cable duct section from the cable duct component, the barb assembly comprising a barb comprising a body and one or more barb arms extending from the body to bitingly engage an end of a cable duct section and to oppose removal of a cable duct section from the cable duct component, and one or more barb arm supports. 
     In another embodiment, there is also provided a cable duct component that can receive an end of a cable duct section, the cable duct component comprising a barb assembly comprising a barb comprising a body and one or more barb arms extending from the body to bitingly engage an end of a cable duct section and to oppose removal of a cable duct section from the cable duct component, and one or more barb arm supports. 
     In another embodiment, there is also provided a cable duct component comprising a barb comprising a body and one or more barb arms extending from the body to bitingly engage an end of a cable duct section and to oppose removal of a cable duct section from the cable duct component, and one or more barb arm supports that can engage one of the barb arms to increase the ability of the barb assembly to oppose removal of the cable duct section from the cable duct component. 
     In another embodiment, there is also provided a cable duct system comprising a cable duct section comprising an end, and a cable duct component that can receive the end of the cable duct section, the cable duct component comprising a barb assembly, the barb assembly comprising a barb comprising a body and one or more barb arms extending from the body to bitingly engage the cable duct section and to oppose removal of the cable duct section from the cable duct component, and one or more barb arm supports. 
     In another embodiment, there is also provided a method for assembling a cable duct system, the method comprising providing a cable duct section comprising an end, providing a cable duct component that can receive the end of the cable duct section, the cable duct component comprising a barb assembly, the barb assembly comprising a barb comprising a body and one or more barb arms extending from the body to bitingly engage the end of the cable duct section and to oppose removal of the end of the cable duct section from the cable duct component, and one or more barb arm supports, and inserting the end of the cable duct section into the cable duct component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention are described herein with reference to the drawings, in which: 
         FIG. 1  depicts an isometric view of a cable duct component comprising a barb assembly with a barb arm support; 
         FIG. 2  depicts a cross-sectional view through a barb assembly and cable duct component; 
         FIG. 2A  depicts a force diagram illustrating a barb arm support embodiment; and 
         FIG. 3  depicts a cross-sectional view through an alternate barb arm support embodiment and cable duct component. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments herein are directed to a new and improved barb assembly with a barb arm support. The barb assembly with the barb arm support can be used advantageously as part of another component, such as a cable duct coupler, for example, to engage and disengage one or more components of cable routing systems. The barb arm support can also be used advantageously with the various releasable barb assembly embodiments described and claimed in U.S. patent application Ser. No. 10/808,974, filed on Mar. 25, 2004, herein incorporated by reference in its entirety. Although several examples of particular embodiments are provided below, it should be understood that all the arrangements described herein are set forth for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other assemblies are contemplated as well. 
       FIGS. 1-3  depict example embodiments of the barb assembly with barb arm support.  FIG. 1  depicts a coupler  224  that can comprise one or more barb assemblies  210 . As shown in the embodiment of  FIG. 1 , a coupler can also comprise one or more barb arm support structures  272 . In one embodiment, the barb arm support structures  272  can be integral with the coupler  224 . Other examples are possible as well. Moreover, cable duct components other than a coupler can comprise a barb assembly with barb arm support structures  272 , such as a reducer fitting or a section of cable duct or raceway, for example. 
       FIG. 2  depicts the barb assembly  210  engaging one or more cable routing components  234 , such as a section of cable duct or raceway, for example. In one embodiment, the barb assembly can include a barb  230  comprising a barb body portion  212  and one or more barb arms  240 , which might be bent back relative to the barb body  212  at an angle greater than 90° and which might comprise an outer surface  278 .  FIG. 2  also depicts the barb arm support structures  272  engaging the outer surfaces  278  of the barb arms  240 . In one embodiment, the barb assembly  210  can comprise two barb arms  240 , and one barb arm support structure  272  can engage one of the barb arms  240  and another barb arm support structure  272  can engage the other barb arm  240 . Other examples are possible as well. 
     Barb arm support structure  272  may take various forms. Referring to  FIGS. 2 and 3 , barb arm support structure  272  may comprise first curvilinear surface  271  and second surface  273 . Curvilinear first surface  271  is typically positioned between bent portion  275  and terminal end  277  of barb arm  240 . Curvilinear first surface  271  also abuts at least a portion of barb arm  240  and opposes movement of barb arm  240  when a pull-out force is applied to a cable duct section. First and second surfaces  271  and  273  may form first end portion  279 , positioned near terminal end  277  of barb arm  240 . Additionally, barb arm support structure  272  may comprise third surface  281  connected to first surface  271  and positioned parallel to second surface  273 . Second and third surfaces  273  and  281  form second end portion  283  spaced apart from first end portion  279 . 
     As depicted in the embodiment of  FIG. 2 , each barb arm  240  can bitingly engage a component  234  in the closed position. When a tensile “pullout” force (depicted by arrow  270 ) is then applied to one of the components  234 , the barb arm  240  (which can have a serrated edge, for example) can penetrate into (or further into) the component  234  and/or can oppose movement of the component  234 . The barb  230  can thus resist separation of the component  234  from the coupler  224 . 
     Failure of a barb  230  might occur, however, if the tensile pullout force  270  is sufficient to overcome the ability of the barb  230  to resist that force. As depicted in the embodiment of  FIG. 2A , the effect of the tensile pullout force  270  on the barb  230  can be measured as a product (“M”) of the magnitude of the force  270  (“F”) and the magnitude of a moment arm  284  (“d”), or as M=Fd, wherein the moment arm  284  is the perpendicular distance from the line of action of the force  270  to a point  280  about which the force  270  acts. Thus, assuming there is a particular magnitude of the moment M that defines the limit of the ability of the barb  230  to resist a tensile pullout force  270 , decreasing the moment arm  284  can thereby advantageously increase the force  270  that the barb  230  can resist. 
     In one embodiment, each barb arm support structure  272  can support one of the barb arms  240  such that the support structure  272  can decrease the magnitude of the moment arm  284  and thereby increase the ability of the barb  230  to resist the tensile pullout force  270 . The embodiment depicted in  FIG. 2  includes two points, a first point  276  and a second point  274 . An embodiment that does not include a barb arm support structure  272  will result in the tensile “pullout” force  270  acting about the point  276 . An embodiment that includes the support structure  272  (as depicted in  FIG. 25 ), will result in the tensile pullout force  270  acting about the point  274 . Thus, in one embodiment, the barb arm support structure  272  can decrease the moment arm  284  (as depicted in  FIG. 2A ) by changing the point about which the tensile pullout force  270  acts, thereby advantageously increasing the tensile pullout force  270  that the barb  230  can resist. 
       FIG. 3  depicts an alternate embodiment of the barb arm support structure  272 . In the embodiment of  FIG. 3 , the tensile pullout force  270  can act about a point  282 . Thus, in the embodiment of  FIG. 3 , the magnitude of the moment arm  284  (as depicted in  FIG. 2A ) is further decreased from the magnitude of the moment arm  284  in the embodiment depicted in  FIG. 2 , thereby further increasing the ability of the barb  230  to resist the tensile pullout force  270 . 
     In some embodiments, the barb arm support structure  272  can actually change the mode of failure of the barb assembly  210 . For example, some placements or constructions of the barb arm support structure  272  could act to reduce the risk of failure of the barb  230  so much that the risk of failure shifts to other components of the barb assembly or cable duct system, such as the component  234 , for example. 
     Several examples of particular embodiments of the present invention have been described above. Those skilled in the art will understand, however, that changes and modifications may be made to these embodiments without departing from the true scope and spirit of the present invention, which is defined by the claims.