Abstract:
A cabinet is provided for managing the connections between a feeder cable and a distribution cable wherein the distribution cable is a blown optical fiber. The cabinet includes shelves for holding splices between the feeder cable and the distribution cable. The shelves also include microduct holders for holding each of the microducts associated with the distribution cable. The cabinet also includes splicing between the feeder cable and a fiber optic splitter. Preferably a fiber termination is provided between the splice and the splitter. The cabinet also includes termination panel between the splitter outputs and distribution pigtails. A connector storage area is also provided. The distribution pigtails are spliced on spliced trays to the blown fibers passed through the microducts.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/713,622, filed Aug. 31, 2005, the disclosure of which is hereby incorporated by reference in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to fiber distribution cabinets for holding fiber optic telecommunications terminations and equipment. 
   BACKGROUND OF THE INVENTION 
   Fiber distribution cabinets are known for holding and managing fiber optic cables, splices, and terminations for cables extending to and from the cabinets. In some cases, the cables extending to and from the cabinets are underground cables. In some systems, conduit is laid between a remote site and a cabinet and then optical fiber is blown through the conduit when needed at a later time. 
   There is a need for cabinets which hold and manage the fiber optic cables, splices, and terminations, as well as interfacing with the conduit through which blown fibers are provided. 
   SUMMARY OF THE INVENTION 
   The present invention relates to cabinets and methods including an enclosure which has a first cable entry and a second cable entry. The cabinet includes structure within the interior for connecting the first cable to the second cable. In one preferred embodiment, a plurality of shelves or trays is provided for holding the connections, such as the splices between the first and second cables. The trays also include holders for holding the conduit including microducts which are used to receive blown fiber as part of the first or second cables. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a fiber optic distribution cabinet, shown with both front and rear doors open; 
       FIG. 2  is a partial exploded front perspective view of the distribution cabinet of  FIG. 1 ; 
       FIG. 3  is a front elevational view of the distribution cabinet of  FIG. 1 ; 
       FIG. 4  is a rear perspective view of the distribution cabinet of  FIG. 1  with portions removed; 
       FIG. 5  is a rear elevational view of the cabinet of  FIG. 1 , showing feeder subunit cables routed to a splice drawer; 
       FIG. 6  is a top perspective of the splice drawer showing feeder pigtails connected to splice trays in the splice drawer; 
       FIG. 7  is a top view of the splice drawer of  FIG. 6 , showing the feeder subunit cables joined to the feeder pigtails at the splice trays; 
       FIG. 8  is a top view of one of the splice trays of the splice drawer of  FIG. 6 , showing one fiber splice; 
       FIG. 9  is a top perspective view of a connector drawer of the cabinet of  FIG. 1 , showing the feeder pigtails joined to splitter input cables at a termination arrangement; 
       FIG. 10  is a top view of the connector drawer of  FIG. 9 ; 
       FIG. 11  is a front elevational view of the cabinet of  FIG. 1 , showing splitter input cables routed from the connector drawer to one of the splitter modules; 
       FIG. 12A  is a front elevational view of a splitter chassis including two splitter modules; 
       FIG. 12B  is a front elevational view of the cabinet of  FIG. 1 , including the chassis of  FIG. 12A  with one splitter module; 
       FIG. 13  is a front elevational view of the cabinet of  FIG. 1 , showing splitter output cables routed to a connector storage panel; 
       FIG. 14  is a front elevational view of the cabinet of  FIG. 1 , showing splitter output cables routed to two connector panels; 
       FIG. 15  is an enlarged view of a portion of one of the connector panels showing a connection between a splitter output cable and a distribution pigtail; 
       FIG. 16  is a top view of one of the connector panels; 
       FIG. 17  is an enlarged perspective view of a lower portion of the cabinet of  FIG. 1 , showing clamping of a conduit to the cabinet, and including microducts extending from the conduit; 
       FIG. 18  is a front elevational view of the cabinet of  FIG. 1 , showing various conduits and microducts extending to microduct holders; 
       FIG. 19  is a top view of one of the shelves of the cabinet of  FIG. 1 , showing connections between distribution pigtails and fibers extending from the microducts at splice trays; 
       FIG. 20  is a top view of one of the splice trays of the shelf of  FIG. 19 , showing one fiber splice; 
       FIG. 21  is a front perspective view of one of the shelves; 
       FIG. 22  is a rear perspective view of the shelf shown in  FIG. 21 ; 
       FIG. 23  is a schematic view showing the various elements of the cabinet of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIGS. 1-4  and  23 , one preferred embodiment of a telecommunications fiber distribution cabinet  10  is shown. Cabinet  10  includes an enclosure  12  for housing connections between a first cable  14  and a second cable  16 . In one embodiment, first cable  14  is a feeder cable, and second cable  16  is a distribution cable. As will be described below, enclosure  12  houses the connections between individual optical fibers associated with each of first and second cables  14 ,  16 . Cabinet  10  is also useful in interfacing with hollow conduit, such as ducts, which can be used for later insertion of optical fibers, such as with a blowing operation. 
   Cabinet  10  includes a base  17 , first and second sides  18 ,  20 , an open front  22 , and an open rear  24 . First and second pivotally mounted doors  26 ,  28  are mounted adjacent to open front  22  and open rear  24 , respectively. Enclosure  12  defines an enclosed interior  30  which receives first and second cables  14 ,  16  and holds and manages the connections between the cables. 
   Referring also now to  FIGS. 5-22  in addition to  FIGS. 1-4  and  23 , cabinet  10  includes a first cable entry  32  through base  17 . First cable  14  can be clamped with a clamp  34 . Typically first cable  14  is an underground cable entering cabinet  10  from beneath base  17 . Clamp  34  can be mounted to an inner vertical panel  36  which further includes cable ties  37  and a cable manager  38 . Such devices are useful for guiding first cable  14  to the various interconnection structures within cabinet  10 . 
   Cabinet  10  also includes a second cable entry  50  allowing second cable  16  to enter cabinet  10 . In the illustrated embodiment, second cable  16  is also an underground cable entering cabinet  10  from beneath base  17 . Second cable  16  includes an outer conduit  52  with a plurality of inner microducts  54 . Conduit  52  is clamped with a clamp  56  to a clamp panel  58 . Microducts  54  are typically installed for later use when an optical fiber interconnection is desired. Cable installation devices are known which insert optical fibers into hollow ducts, such as through a blowing operation which uses pressurized air to install the optical fiber in the duct. Cabinet  10  allows for initial placement conduit  52  with microducts  54  where the optical fibers  60  are installed at a later date in microducts  54 . 
   A plurality of trays or shelves  70  hold ends  62  of microducts  54  with a microduct holder  200 . Shelves  70  also hold fiber splices for joining fibers  60  to further fibers connected to first cable  14 , as will be described below, thereby completing the connection between first cable  14  and second cable  16 . 
   Referring now to  FIGS. 6-8  and  23 , first cable  14  in the form of feeder subunit cables  80  enter splice drawer  100 . Splice drawer  100  includes a chassis  102  and a moveable tray  104 . Moveable tray  104  holds one or more splice trays  106 . Splice trays  106  include splice chips  108  which hold the individual splices  110  between feeder subunit cables  80  and feeder pigtails  82 . 
   Referring now to  FIGS. 9 ,  10  and  23 , feeder pigtails  82  are shown being connected to splitter input cables  84  in a connector drawer  120 . Connector drawer  120  includes a chassis  122  and a moveable tray  124 . Mounted on tray  124  is a plurality of terminations of  126 . Terminations  126  include a connector  128  on the end of each feeder pigtail  82  and each splitter input cable  84  which are joined together in an adapter  130 . 
   Splice drawer  100  and connector drawer are mounted to panel  36  at mounting strips  39  which receives fasteners. Further features of splice drawer  100  and connector drawer  120  are shown and described in greater detail in U.S. Pat. Nos. 6,438,310, 6,504,988, and 7,079,744, the disclosures of which are hereby incorporated by a reference. 
   Referring now to  FIGS. 11-14 , splitter input cables  84  are shown being split into splitter output cables  86  which are either stored in a fiber storage device  150  ( FIG. 13 ) or terminated to other cables at connector panel  160  ( FIG. 14 ). Each splitter module  170  includes an input port  172  and one or more output ports  174  in the illustrated embodiment. For example, each splitter module  170  can split a splitter input cable  84  into a plurality of splitter output cables  86 , such as a 1×32 splitter. Splitter modules  170  are mounted in a chassis  176  which mounts to mounting strips  39  with fasteners. A cable manager  180  helps manage slack associated with splitter output cables  86 . 
   When splitter output cables  86  are not yet needed for connection to downstream equipment, storage panel  150  is used to hold each splitter output cable  86 . Preferably, each splitter output cable  86  includes a connector  128 . Preferably, connector storage panel  150  can receive each connector  128 , or a group of connectors, including a dust cap over an end of a ferrule associated with connector  128 . Further features of exemplarily connector storage panels  150  and holders are shown and described in U.S. Pat. No. 7,218,827, the disclosure of which is hereby incorporated by reference. 
   When a downstream connection is desired, a splitter output cable  86  is removed from connector storage panel  150  and connected to a front of connector panel  160 . Referring now to  FIGS. 15 and 16 , connector panel  160  includes a plurality of adapters  130  for joining two connectors  128 . Once connected, splitter output cable  86  is optically linked to a distribution pigtail  88  which is led from connector panel  160  to one of shelves  70 . Connector panel  160  in the illustrated embodiment has a chassis  163  mounted to mounting strips  39  with fasteners, and a pivoting panel  164  for holding the adapters  130 . A cable manager  182  ( FIG. 4 ) manages distribution pigtails  88  between connector panels  160  and shelves  70 . 
   Referring now to  FIGS. 17-22 , distribution pigtails  88  are joined to fibers  60  through splice tray  190  on each shelf  70 . Each shelf  70  includes a microduct holder  200  which holds an end  62  of one of the microducts  54 . Specifically, microduct holder  200  includes a plurality of holes  202  which are sized to closely surround an exterior of each microduct  54 . The circular periphery defined at each hole  202  engages an exterior of the microduct  54  to frictionally hold the microduct relative to shelf  70 . In the illustrated embodiment, microduct holders  200  are shown positioned in a side plate  204  of each shelf  70 . The holes  202  can be punched from sheet metal. If desired, an insert can be mounted to shelf  70 , or to a vertical panel adjacent to shelf  70  so as to provide the circular holes  202  separate from shelf  70 . Also, a variety of microducts  54  can be used. A differently sized microduct holder  200  is utilized for different microducts. For example, an outside diameter of the microducts can vary from 3 millimeters, to 5 millimeters, to 7 millimeters. To facilitate insertion, an end  62  of each microduct  54  is provided with a tapered shape (45 degree angle) so as to permit easier insertion in each hole  202 . This can be cut off square as desired after insertion. In the case of a 5 millimeter duct, a hole having a diameter of 0.189 inches +/−0/0.002 inches will allow insertion of each duct without excessive effort or damage to the duct, and then retain each duct with sufficient retention force. 
   On a base  208  of each shelf  70  a tie device  210  can be provided for tying ends  62  of microducts  54  to each other or to each shelf  70 . Base  208  of each shelf  70  further includes cable radius limiters  212  for managing the cables on each shelf  70 . Shelf  70  further includes splice tray mounts  214  for holding splice trays  190  on shelves  70 . Each splice tray  190  includes a splice chip  192  for holding a splice  194  used to join each distribution pigtail  88  to each fiber  60 . 
   Each shelf  70  further includes a slot  220  for use in passing first cable  14  from base  17  to splice drawer  100  located adjacent a top  21  of cabinet  10 . Shelves  70  further include an aperture  222  for allowing distribution pigtails  88  to pass to the appropriate shelf  70  for connection to the fibers  60  located on each shelf  70 . 
   In this manner, microducts  54  can be installed to cabinet  10 , and the blown fiber inserted later. It is anticipated that the blown fiber can be inserted from either end of microduct  54 , either at end  62 , or at the remote end disposed at the remote site. 
   Cabinet  10  manages the feeder cables  14  and the duct  54  of the distribution cable  16 , so that a user can install blown fiber at a later date, and then make appropriate connection to the feeder cable, such as with a splice on shelf  70 . The other functions provided by cabinet  10  also allow ease of use, such as the access provided by each of drawers  100 ,  120 , splitters  170 , connector panel  160 , as well as the various cable managers.