Abstract:
A cable guide and trough device for preventing the over-bending of cables, fibers, and/or wires generally comprises a plurality of links each having a base and a pair of opposing sidewalls defining a passageway for guiding the cables. The links are connected at pivots located at the ends of the links to permit rotation of the links about an axis perpendicular to the base. This rotation is limited by the abutment of the respective sidewalls of adjacently connected links. Preferably, the sidewalls are bowed into the passageway so that a substantially smooth inner curve is achieved when the device is fully flexed.

Description:
FIELD OF THE INVENTION 
     The invention relates to an expandable fiber trough for protecting fibers and, in particular, to an expandable trough having a bend limiting feature. 
     BACKGROUND OF THE INVENTION 
     In the telecommunications industry, wires, including fiber optic cables, are often housed in and connected to shelves, cabinets or other storage articles. The fibers in the shelves are accessed by sliding the shelf out to expose the fiber connections. Because the shelves are movable, some slack is provided in the fibers to prevent them from being detached from the connectors housed in the shelf. However, this extra length of fiber can cause the fibers to become tangled and/or excessively bent when of the shelf is closed. Excessive bending can cause the fibers to become damaged or inoperative resulting in unnecessary expense and maintenance. 
     Therefore, there is a desire and need to provide an apparatus for preventing the tangling and excessive bending of fiber cables in such shelves. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes shortcomings of the prior art. According to the present invention, a cable organizer and bend-limiting device generally comprises a plurality of links interconnected at pivots to permit the links to rotate about pivots and thus form a flexible trough or channel capable of being moved into and out of a variety of serpentine shapes and paths. Each of the links preferably include a passageway for retaining one or more cables. The passageway is preferably defined by a base, a first sidewall extending from a side of the base, and a second sidewall extending from an opposite side of the base. The rotation of the links about the pivots is limited to a distance between the respective first and second sidewalls of connected links, so as to limit the bending of the passageway. Consequently, the bending of the cable(s) retained therein is limited to a desired radius of curvature, and the trough-like shape formed by the interconnected links aids in keeping the fibers organized, untangled and securely maintained as the storage shelf is opened or closed. 
     According to a preferred embodiment of the present invention, the links are connected to one another through the engagement of male and female members, which extend from opposite ends of the links. Preferably, the links may be releasably snapped together so as to provide simple assembly and flexible length configuration. The connection forms a pivot about which each of the links can rotate relative to the other link to which it is connected. The rotation is preferably about an axis perpendicular to the base. The base, first sidewall, and second sidewall define a passageway or trough through which a cable or group of cables may be fed and retained to prevent over-bending, tangling, or pinching of the cables. As used herein, the term “cable” or “cables” refers to any cable, wire, conductor, fiber optic cable, and the like, or other flexible elongated structure or member needing to be organized in a manner described herein. 
     In a fully extended condition, the sidewalls of each of the links are spaced from the respective sidewalls of the adjacent link, thereby permitting the links to rotate about the pivot connections. The distance between the respective sidewalls determines the angle that the links can sweep before abutting one another and limiting the bend of the passageway. By decreasing or increasing this distance, the desired radius of curvature can be similarly decreased or increased. Moreover, the first and second sidewalls may be bowed into the passageway at a radius of curvature substantially equally to the desired radius of curvature of the bend-limiting device to further facilitate the bending of the passageway to a desired radius of curvature. As will become apparent from the teachings herein, any number of links may be connected depending on the particular application of the bend-limiting device. 
     Because the radius of curvature can be pre-determined to accommodate particular types of cables, the present invention advantageously prevents delicate cables and/or fibers from being over-bent during the opening and closing of cable shelves. 
     Other objects and features of the present invention will become apparent from the following detailed description, considered in conjunction with the accompanying drawing figures. It is to be understood, however, that the drawings, which are not to scale, are designed solely for the purpose of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the figures, which are not to scale, and which are merely illustrative, and wherein like reference numerals depict like elements throughout several views: 
     FIG. 1 is a top view of a bend limiting device in accordance with a preferred embodiment of the present invention; 
     FIG. 1A is a top view of three links of a preferred embodiment of the device of FIG. 1, wherein the links are in an expanded condition with a cable shown carried therein; 
     FIG. 2 is a top perspective view of a link for use with the device of FIG. 1; 
     FIG. 3 is a side view of a link for use with the device in FIG. 1; 
     FIG. 4 is a side view of a pair of interconnected links for use with the device in FIG. 1; 
     FIG. 5 is a top view of a shelf fitted with the device of FIG. 1, wherein the device is in a flexed condition; and 
     FIG. 6 is a top view of the shelf and device of FIG. 5, wherein the shelf is opened and the device is in an expanded condition. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1-6, there is shown a preferred embodiment of the present invention wherein a bend-limiting device  10  for limiting the bend of a cable (shown in FIG. 1A) generally comprises a plurality of links  20  interconnected at pivots  100 ,  100 ′ to permit the links to rotate about the pivots  100 ,  100 ′. Each link  20  of the device  10  includes a passageway  22  for retaining the cable. The passageway  22  is defined by a base  24 , a first sidewall  70  extending from a side  26  of base  24 , and a second sidewall  80  extending from an opposite side  27  of base  24 . 
     Referring now to FIG. 1, there is shown a preferred embodiment of device  10  having a plurality of interconnected links  20 . As depicted, a first and second section A and B, respectively, of device  10  are fully flexed to a desired radius of curvature R. With further reference to FIG. 2, each link  20  preferably includes at least first and second members  40  and  60  that extend from opposite ends  29 ,  30  of base  24 . As will be further described, the first member  40  of each link  20  is connectable to the second member  60  of another link  20 . When the links  20  are connected, as shown in FIG. 1A, the first and second sidewalls  70 ,  80  of each link  20  are separated from the first and second sidewalls  70 ,  80  of adjacent links  20 ′ and  20 ″. This separation permits the links  20  to rotate about pivots  100 ,  100 ′ until the respective first sidewalls  70  or second sidewalls  80  (depending on the direction that device  10  is bent) contact one another, as shown in FIG.  1 . The separation between the respective sidewalls of adjacent links is proportional to the amount of rotation of each link and, therefore, proportional to the total radius of curvature of device  10  when it is fully flexed. As such, an advantage of the present invention is that a desired radius of curvature R can be determined and designed into device  10  to prevent over-bending of particular types of cables guided by passageway  22 . 
     With further reference to FIG. 1A, there is shown a cable  5  fed through passageway  22  of a preferred embodiment of the present invention. One skilled in the art will recognize from the teachings herein that cable  5  may be a single cable of varying thickness or a bundle of cables or a group of individual cables (or fibers). In addition, any elongate members or bundle of elongate members may be fed and guided through the present invention. 
     With reference now to FIG. 2, there is shown in detail a preferred embodiment of a link  20  for use with the present invention. As depicted, the first and second sidewalls  70 ,  80  are preferably, but not necessarily bowed inwardly into passageway  22 . Preferably, the first and second side walls  70 ,  80  are bowed at a radius of curvature substantially equal to the desired radius of curvature R. When the radius of the bowing is substantially equal to the desired radius of curvature R, the sidewalls  70  or  80  (depending on the direction device  10  is flexed) will abut one another so as to form a substantially smooth inner edge  15  (shown in FIG.  1 ). One skilled in the art will recognize from the teachings herein, however, that the degree to which sidewalls  70 ,  80  are bowed is a matter of design choice and that the sidewalls need not be bowed at all for the invention to function. Preferably, the links are made of a plastic, non-conductive material and molded for manufacturing efficiencies, however those of skill in the art will recognize from the teachings herein that the links can be made of any suitable material on a matter of design choice, and sized and shaped as a matter of application specific need. 
     Referring now to FIGS. 2 and 3, a preferred embodiment of link  20  is shown. In this preferred embodiment, the base  24  has three levels  32 ,  33 ,  34  from which the first and second members  40  and  60  extend. One skilled in the art will recognize that although first and second members  40  and  60  need to be connectable (i.e., male/female engagement), the particular way of achieving such connection is not critical to the present invention, provided that the links can be matingly pivotably assembled to perform the features and functions described herein. In a preferred embodiment, for example, the first member  40  includes a pair of opposing portions  42  and  46 , which extend from the first and third levels  32  and  34 , respectively. Opposing portions  42 ,  46  preferably have semicircular edges to facilitate the rotation of the links  20 . Each portion  42 ,  46  also has an aperture  43  and  47  formed therethrough. Preferably, the apertures  43 ,  47  are positioned relative to ends  29 ,  30  of base  24 , such that the resulting pivots  100 ,  100 ′ formed upon linkage of adjacent links separate the sidewalls of connected links, as described above. 
     The second member  60 , includes at least one portion  62 , which extends from the second level  33  of the base  24  and, is located at end  30 . Like opposing portions  42  and  46 , portion  62  also preferably has a semicircular edge. A pair of protrusions  64 ,  64 ′ are formed on opposite surfaces of portion  62 . Thus, as depicted in FIG. 4, the protrusions  64 ,  64 ′ of the second member  60  of link  20  engage the apertures  43 ′ and  47 ′ of the first and third portions  42 ′,  46 ′ of the first member  40 ′ of a second link  20 ′ in a snap fit mating engagement. Once connected, the links can rotate about the resulting pivot  100 . 
     Referring again to FIGS. 1-3, in a preferred embodiment of the present invention, one or more fingers for retaining a cable within passageway  22  is preferably provided on each link  20 . A first finger  72  extends from the first sidewall  70  into and over the passageway  22 . The first finger  72  is preferably positioned near one of the ends of link  20 . A second oppositely facing finger  82  extends from the second sidewall  80  into and over passageway  22 . The second finger  82  is preferably positioned near an end of link  20  opposite from the end near which the first finger  72  is positioned. In use, a cable (not shown) can be fed around the fingers  72 ,  82  and into passageway  22 . Because the fingers  72 ,  82  extend over the passageway  22 , the cable is retained in passageway  22  by the fingers. It should be noted that although it is preferable to provide fingers  72  and  82 , the cable can be retained in passageway  22  by any other means known in the art. For example the side walls can be ribbed or retainers positioned across passageway  22 . 
     As is shown in detail in FIGS. 2 and 3, in a preferred embodiment of the present invention each link  20  is provided with screw hole  37  to facilitate the fixed mounting of one or more links to a support structure. Screw hole  37  is formed through base  24  and includes a recess  39  for receiving the head of a screw (not shown), such that the screw head sits flush with the surface of the third level  34  of base  24 . Any art recognized mounting methodology, however, may be used to secure a link to a support structure. 
     With reference to FIGS. 5 and 6, an example of one illustrative use of a preferred embodiment of the present invention will now be described. A preferred embodiment of the present invention may be advantageously deployed with a fiber optic cable shelf, tray or other moveable object upon which cables are mounted, connected or fed, the shelf being slidably housed in a cabinet  200  or other similar art recognized housing or structure. Shelf  250 , by way of non-limiting example, is slidably mounted to cabinet  200  by way of a pair of screws  210 ,  210 ′ that pass through a first and second sidewall  202  and  204 , respectively, of cabinet  200 . The sidewalls  202  and  204  are each constructed to permit screws  210 ,  210 ′ to slide between points X and Y, thereby permitting shelf  250  to be slidably opened and closed. One skilled in the art will recognize that although a preferred embodiment of the present invention is shown, shelf  250  may be slidably mounted in cabinet  200  in any manner known in the art. As previously described, fiber optic cables may be terminated or connected to such shelves in any art recognized manner, such as for example, as shown in FIGS. 5 and 6. 
     As depicted in FIG. 5, shelf  250  is shown in a closed position. Bend-limiting device  300 ,  300 ′ is fixed to cabinet  200  at end  310 ,  310 ′. Similarly, bend-limiting device  300 ,  300 ′ is fixed to shelf  250  at end  320 ,  320 ′. The cables  400  housed within shelf  250  are fed into the passageway  305 ,  305 ′ of the bend-limiting devices  300 ,  300 ′ at ends  320 ,  320 ′. In this example, a portion  330 ,  330 ′ of device  300 ,  300 ′ is pre-flexed to the desired radius of curvature R to permit the device (and the cables) to pass around the sidewalls  202  and  204  of cabinet  200  and out of cabinet  200 . 
     To access the cables  400 , shelf  250  is slid outwardly from cabinet  200 . As depicted in FIG. 6, ends  320 ,  320 ′ move outwardly with the shelf  250  as it is opened, while ends  310 ,  310 ′ remain fixed to cabinet  200 . As the shelf  250  is opened, a portion of the devices  300 ,  300 ′ straighten (sections A, A′), while another portion flexes (section B, B′) to accommodate the outward movement of the shelf  250 . Consequently, as shelf  250  is closed and opened, the bendlimiting device  300 ,  300 ′ guides the retained cables and prevents the cables from becoming pinched or over-bent. Numerous shapes can be assumed by the device depending on how the individual links are sized shaped relative to each other. 
     One skilled in the art will recognize that the bend-limiting device disclosed herein is not limited to the uses described herein, but may be used in applications pertaining to any field where there is a need to retain cables or other elongate flexible members and/or to limit the bending to which the cables are subjected. 
     With reference to the various figures and embodiments of the present invention, it should be noted that the bend limiting feature of the present invention need not be limited to the abutment of the sidewalls  70  and  80 . Rather, link  20  may be provided with a limiting member, such as, by way of non-limiting example, a tab extending from the base  24  or a projection formed on protrusions  64 ,  64 ′ (not shown), or some other protrusion or surface feature may be provided on the link to limit the extent of bending of the cable guide. Furthermore, one skilled in the art will recognize that sidewalls  70  and  80  need not be solid or continuous, so long as the sidewalls  70  and  80  are sufficient to retain the cables within passageway  22 . 
     Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the form and details of the disclosed invention may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.