Abstract:
A fiber optic cable distribution frame assembly includes a support frame in which a number of drawers are slidingly supported for movement between stored and extended positions. Incoming and outgoing fiber optic cables are routed to each drawer. Each drawer supports rows of termination connector support brackets, each such bracket including two or more connector support columns. Each such support column has first and second sets of support arms extending therefrom in opposing directions. The support arms extend at an angle of between 25 degrees and 65 degrees relative to the plane in which the drawer slides. An adaptor is supported by each of the support arms. Each adaptor receives termination connectors from a selected pair of incoming and outgoing fiber optic cables for removably coupling the selected pair of fiber optic cables.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the management of telecommunications cabling, and more specifically, to distribution frames used for fiber optic cables. 
     2. Description of the Relevant Art 
     Fiber optic cables have found increasing usage in the telecommunications industry as a result of their greater bandwidth and immunity from noise. As in the case of conventional copper electrical conductors, fiber optic cables used in the telecommunications industry are typically bundled together in large bundles. At various locations within a fiber optic cable system, including at the central office of the telecommunications system operator, in Controlled Environment Vaults (CEVs) out in the field, and at the premises of larger customers, it is often necessary to terminate and distribute a large number of incoming and outgoing fiber optic cables. Typically, the bundles of fiber optic cables include a relatively large number of individual optical fibers. The task of keeping such large number of optical fibers organized at such termination/distribution points, so that the optical fibers can be properly distributed throughout the system, poses a significant challenge. 
     The space available at such termination/distribution points is often at a premium, so it is important to maintain a relatively high density of optical fiber connections at such locations to minimize the space required. On the other hand, optical fibers can not be bent along sharp bends without risk of damaging such fibers, so any system for connecting together the ends of such incoming and outgoing fibers must support the optical fibers in such a way as to avoid such sharp bends. Moreover, high density must not come at the cost of making it more difficult to properly identify particular incoming and outgoing fibers; otherwise, the system operator will not be able to efficiently maintain, modify, and diagnose the fiber optic system. 
     U.S. Pat. No. 4,995,688 to Anton, et al. discloses an optical fiber distribution frame for terminating and distributing fiber optic cables. The disclosed frame includes a series of modular cabinets, including a connector cabinet having an essentially planar front panel with sleeve adaptors for mounting a plurality of connector sleeves thereto at an angle to the front panel. 
     U.S. Pat. No. 5,363,465 to Korkowski, et al. discloses a fiber optic connector module that includes a framework for receiving circuit card cartridges, and each of the cartridges include electrical connectors for attachment to telecommunication wires and cables. The connectors are angled so that the bending radius of the cables is not too sharp as to cause damage to the cable. 
     However, the apparatus disclosed by the two above-mentioned patents fails to achieve the packing density, ease of identification, and convenience obtained by the invention that is the subject of the present application. 
     Accordingly, it is an object of the present invention to provide a fiber optic cable distribution frame which facilitates the connection of pairs of incoming and outgoing optic fibers as a highly dense, space-saving structure without concern for bending the optical fibers around too sharp a bend. 
     Another object of the present invention is to provide such a distribution frame which conveniently organizes a relatively large number of optical fibers at a termination/distribution points, and which allows such optical fibers to be easily identified so that they can be properly distributed throughout the fiber optic cable system. 
     Still another object of the present invention is to provide such a distribution frame as a highly dense structure, but which provides ready and convenient access to each coupled connection between incoming and outgoing optical fibers in order to efficiently maintain, modify, and diagnose the fiber optic system. 
     These and other objects of the present invention will become more apparent to those skilled in the art as the description of the present invention proceeds. 
     SUMMARY OF THE INVENTION 
     Briefly described, and in accordance with a preferred embodiment thereof, the present invention relates to a fiber optic cable distribution frame assembly for interconnecting fiber optic cables, and including a support frame for supporting at least one, and preferably a number of slide-out drawers for movement between a stored position inside the support frame and an extended position projecting from the support frame. In the preferred embodiment, the drawers are arranged vertically, and each drawer slides within a movement plane that extends parallel to the corresponding movement planes of the other drawers. Preferably, the support frame includes a slide track for slidably mounting each drawer thereto. 
     Each drawer includes at least one, and preferably several, termination connector support brackets that are used to support fiber optic cable connectors in a highly-dense manner. The termination connector support bracket generally parallel to and primarily within, the movement plane of the drawer to which it is attached. Each termination connector support bracket includes two or more termination connector support columns, each of which extends vertically in the preferred embodiment of the present invention. Each such termination support column has a first set of connector support arms that extend therefrom in a first direction, as well as a second set of connector support arms that extend generally in the opposite direction. The first and second sets of support arms extend at an offset angle from the movement plane of the drawer; this offset angle ranges between 25 degrees and 65 degrees, and is preferably between 35 degrees and 55 degrees from the movement plane of the drawer. Since the first and second sets of support arms extend in opposite directions, and since they are offset from the drawer movement plane, the first and second sets of connector support arms are disposed on opposite sides of the termination connector support column relative to the drawer movement plane; thus, the first and second sets of support arms extend on opposite sides of the drawer movement plane. 
     Each drawer is adapted to receive a number of incoming and outgoing optical fibers; the ends of such optical fibers include termination connectors, and the termination connector of one incoming Optical fiber must be coupled with the termination connector of a respective outgoing optical fiber. To this end, a series of incoming fiber optic cable curved guides may be provided on each drawer for partially supporting incoming optical fibers, and for guiding each incoming fiber optic cable to a related coupling adaptor; likewise, a series of outgoing fiber optic cable curved guides may be provided on each drawer for partially supporting outgoing optical fibers, and for guiding each outgoing fiber optic cable to a related coupling adaptors. 
     A series of such coupling adaptors are secured to, and supported by, the aforementioned connector support arms. Each such adaptor is adapted to receive a termination connector of a selected incoming optical fiber and a termination connector of a selected outgoing optical fiber for removably coupling such optical fibers together. 
     In the preferred embodiment of the present invention, the termination connector support bracket, including its termination connector support columns and associated connector support arms, are formed of a single piece of material, such as a sheet of metal that is punched and formed to provide such components. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a fiber optic cable distribution frame assembly for interconnecting fiber optic cables in accordance with the present invention, and including a support frame and six pull-out drawers. 
     FIG. 2 is a side view of a pull-out drawer shown in FIG. 1 from a first side. 
     FIG. 3 is a side view of the same pull-out drawer shown in FIG. 2 from the opposite side. 
     FIG. 4 is an enlarged, partial view of a termination connector support bracket supported by a pull-out drawer. 
     FIG. 5 is an enlarged view of the curved fiber optic cable guides and related termination connectors and adaptors encircled by dashed circle  5  within FIG.  2 . 
     FIG. 6 is an enlarged view of the curved fiber optic cable guides encircled by dashed circle  6  within FIG.  3 . 
     FIG. 7 is a detailed view of an additional curved cable guide housed behind the front panel of the drawer for storing lengths of fiber optic cable, as viewed from the plane designated by arrows  7 — 7  in FIG. 2.. 
     FIG. 8 is a sectional view of the pull-out drawer and termination connector support bracket taken through the plane indicated by lines  8 — 8  shown in FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A fiber optic cable distribution frame assembly for interconnecting fiber optic cables in accordance with the present invention is designated generally by reference numeral  20  in FIG.  1 . Frame assembly  20  includes a support frame  22  preferably made of metal components. A series of six pull-out drawers  24 ,  26 ,  28 ,  30 ,  32  and  34  are supported by frame  22 . Within FIG. 1, drawer  24  is shown in its extended position projecting from support frame  22 , while the remaining pull-out drawers  26 ,  28 ,  30 ,  32  and  34  are shown in their stored position within support frame  22 . Each of drawers  24 ,  26 ,  28 ,  30 ,  32  and  34  are slidingly supported to frame  22  by an upper slide track and a lower slide track. For example, as shown in FIGS. 1 and 2, pull-out drawer  24  is supported by upper slide track  36  and lower slide track  38 . These slide tracks allow such drawers to be movable between the stored position and the extended position along a movement plane. These pull-out drawers may also be formed of metal. Each pull-out drawer preferably includes a handle, like handle  40  on pull-out drawer  24 , to aid in pulling the drawer from the support frame, and to aid in replacing the drawer back into the support frame. 
     Each pull-out drawer supports four termination connector support brackets; as shown in FIGS. 1-3, drawer  24  supports the four termination support brackets identified by reference numerals  42 ,  44 ,  46  and  48 . Each of such termination support brackets extends generally within the movement plane defined by the sliding motion of drawer  24 . Each of the termination support brackets includes three termination connector support columns; for example, as shown in FIGS. 2 and 3, lowermost termination connector support bracket  48  includes support columns  50 ,  52 , and  54 . Each of such support columns includes a first set of connector support arms extending therefrom in a first direction and a second set of connector support arms extending therefrom in the opposing direction. Turning to FIG. 8, for example, support column  50  includes support arm  56  extending in a first direction and support arm  58  extending generally in the opposite direction. As is also shown in FIG. 8, support column  52  includes a support arm  60  extending in a first direction and support arm  62  extending in the opposing direction. Likewise, support column  54  includes support arm  64  extending in a first direction and support arm  66  extending in the opposite direction. 
     As indicated in FIGS. 2 and 3, pull-out drawer  24  includes a vertically-extending panel  68  disposed just behind, and perpendicular to, the front panel  25  of pull-out drawer  24 . Likewise, pull-out drawer  24  includes a vertically-extending panel  70  disposed just ahead of, and perpendicular to, the rear panel  72  of drawer  24 . Referring again to FIG. 8, panels  68  and  70  define, and lie within, a plane that coincides with the sliding plane of drawer  24 . As shown best in FIG. 8, support arms  56  and  58 ,  60  and  62 , and  64  and  66 , each extend at an offset angle to the movement plane defined by panels  68  and  70 . As shown in FIG. 8, these offset angles are approximately 45 degrees. Preferably, these angles are within the broad range between 25 degrees and 65 degrees, but usually within the narrower range of 35 degrees and 55 degrees. Such angles provide the best compromise of high packing density, narrow drawer width, and avoidance of sharp bend angles on the optical fibers. 
     With regard to FIG. 4, termination connector support bracket  48  is shown in greater detail. Support column  50  includes a first set of support arms that includes those designated by reference numerals  56 ,  57 ,  59 ,  61 ,  63  and  65 , all of which extend at the same angle from support column  50 , and all of which extend in the same general direction as each other. The second set of support arms extending from support column  50  includes those designated by reference numerals  58 ,  67 ,  69 ,  71 ,  73 , and  75 , all of which extend at the same angle from support column  50 , and all of which extend in the same general direction as each other, opposite to the corresponding direction for the aforementioned first set of support arms. 
     Shown in FIGS. 4 and 8 is an incoming optical fiber  74 , an outgoing optical fiber  76 , and an adaptor  78  for coupling together the ends of optical fibers  74  and  76  in order to form a continuous light path. The ends of optical fibers  74  and  76  are thin and fragile, and it is accordingly necessary to reinforce such ends before joining them to adaptor  78 . Accordingly, the end of optical fiber  74  includes a termination connector  80  designed to interlock with adaptor  78 ; the combined optical fiber and termination connector is sometimes known in the trade as a patch cord or pig tail. Likewise, the end of optical fiber  76  includes a termination connector  82  also designed to interlock with adaptor  78 . 
     Adaptor  78  is secured to termination connector support bracket  48  by inserting adaptor  78  between two adjacent support arms, such as  60  and  60 ′. As many as 16 such adaptors can be inserted within the first set of support arms extending from support column  52 , and another 16 adaptors can be inserted between the second set of support arms (including support arm  62 ) which extend from the opposite side of support column  52 . Thus each slide drawer has the capacity to hold 32 adaptors times 3 support columns per bracket times 4 brackets per drawer, or 384 adaptors. Accordingly, each pull-out drawer can couple as many as 384 pairs of incoming and outgoing optical fibers. 
     As mentioned above, fiber optic cables should not be sharply bent. Accordingly, pull-out drawer  24  includes curved guides for supporting the incoming and outgoing fiber optic cables within drawer  24 . Referring to FIGS. 2 and 5, rear vertical panel  70  includes a series of quarter-turn curved arches, such as those designated by reference numerals  84 ,  86 ,  88  and  90  for gently guiding fiber optic cables running up vertically along rear panels  70  and  72  to a horizontal path at approximately the horizontal elevation of the adaptors to which they are to be coupled. For example, guide  84  gently bends outgoing optical fiber  92  toward adaptor  94 , while guide  86  gently bends outgoing optical fiber  96  toward adaptor  98 . Similar quarter-round guides are provided on forward vertical panel  68  (see FIG.  3 ), such as  97  and  99  for guiding optical fibers running down front panels  25  and  68  and gently bending such optical fibers into a horizontal path over toward their respective adaptors. 
     As shown in FIGS. 3 and 6, rear panel  70  may also include guide members  100  and  102  secured thereto for supporting excess lengths of fiber optic cable within drawer  24 . Guide member  100  includes a cylindrical surface, shown in dashed outline in FIG. 6 by reference numeral  104 , and guide member  102  includes a similar cylindrical surface  106 . The excess length of fiber optic cables  111  and  113  are wrapped about guides  102  and  106 . Oversized square-shaped caps  108  and  110  cover the outer ends of cylinders  104  and  106 , respectively, to ensure that the wrapped portion of cables  111  and  113  do not slide off of the ends of such cylinders. 
     Referring to FIGS. 2 and 7, pairs of half-round curved guides, such as those designated as  112  and  114 , are secured to the rear-facing side of front panel  25 , again for supporting excess lengths of fiber optic cable within drawer  24 , such as fiber optic cables  116  and  118 . Retainer flanges  120 - 128  prevent fiber optic cables  116  and  118  from sliding off of guides  112  and  114 . 
     As mentioned above, the termination connector support brackets, for example support bracket  48  including the support columns  50 ,  52 , and  54 , and support arms such as  56 ,  57 ,  58  and  67 , can all be made from a single piece of material. For example, a single piece of sheet metal can easily be punched and formed to provide such support brackets. 
     Those skilled in the art will now appreciate that an improved fiber optic cable distribution frame assembly for interconnecting fiber optic cables has been described which is adapted to removably couple selected pairs of incoming and outgoing fiber optic cables. The frame assembly of the present invention provides a significantly higher density than known in the prior art while making it relatively easy for a technician to locate any particular junction between an incoming and outgoing fiber optic cable. Moreover, such high density is achieved without risking sharp bends to such cables as might compromise the integrity of such cables. 
     While the present invention has been described with respect to preferred embodiments thereof, such description is for illustrative purposes only, and is not to be construed as limiting the scope of the invention. Various modifications and changes may be made to the described embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.