Patent Publication Number: US-2022221674-A1

Title: Fiber optic cable storage devices, systems and methods

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is being filed on May 28, 2020 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Ser. No. 62/855,710, filed on May 31, 2019, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to fiber optic telecommunications equipment and components. More particularly, the present disclosure relates to devices, systems and methods for storing fiber optic cables, such as loops of fiber optic cable slack. 
     BACKGROUND 
     Telecommunications systems, for example fiber optic closures and other devices, can involve the storage of fiber optic cable components such as splices, splitters, or other devices, and the accompanying fiber optic cable connecting to those components. Slack management is important, especially with respect to splicing. The slack fiber optic cable is needed for accessing the fusion splicing equipment to connect the two fibers. Excessive slack is not a preferred situation in that such slack takes up more space and/or needs to be organized and managed. 
     In the case of a repair of fiber optic connections, such as a re-splice, additional issues arise with respect to managing the slack. If a repair technician is required to re-route fiber optic cables inside or outside of the closure to locate additional slack to make the repair, such events can be time consuming or costly. 
     Additionally, the overall size of outside plant closures in general, and repair closures in particular, may be limited. For example, there may be size limits so the closures do not hinder placement in the field. Therefore, if the internal slack storage is limited in space it may limit the technician&#39;s ability to properly manage short lengths of spliced fiber required in these smaller closures. 
     Improvements are desired. 
     SUMMARY 
     This disclosure pertains to routing of fiber optic cables in an organized manner within a fiber optic tray or other device where fiber optic cable slack needs to be stored. 
     This disclosure further pertains to management of fiber optic cable slack in a manner where the fibers are managed in loop shapes without going below the minimum bend radius of the respective cable. 
     This disclosure further pertains to management of fiber optic cable slack in a manner where the fibers are connected to other fibers or devices on both ends, and the slack is managed in loop shapes without having unmanaged segments that can interfere with other cables, get damaged, or create organization and/or use problems for the technician. 
     This disclosure pertains to devices, systems and methods for management of fiber optic cable slack in a manner where the fibers are managed in loop shapes without going below the minimum bend radius of the respective cable, and where the minimum bend radius for the specific cable to be stored can be accounted for during assembly of the cable storage device. 
     This disclosure relates to managing fiber optic cables wherein the slack lengths to be managed may vary between the different fiber optic cables being managed by the fiber optic tray or other device. 
     This disclosure pertains to fiber optic cable storage devices, systems and methods used to store cable slack. The devices, systems and methods include a substrate, such as a tray in a telecommunication closures of the type found in the outside plant. Cable management devices are provided on the substrate for containing one or more fiber loops. 
     In one embodiment, two cable management devices are provided on the substrate facing one another. 
     In another embodiment, the two cable management devices allow for storage of fiber loops having a length defined by a cable in a full loop having the radius of the minimum bend radius of the cable. 
     In another embodiment, the two cable management devices allow for storage of fiber loops having a length defined by a cable in a full loop having the radius of the minimum bend radius of the cable up to and including a length twice as long as the full loop having the radius of the minimum bend radius of the cable. 
     In another embodiment, the two cable management devices allow for storage of fiber loops having a length defined by a cable in a full loop having the radius of the minimum bend radius of the cable up to and including a length twice as long as the full loop having the radius of the minimum bend radius of the cable; wherein no linear segments are defined by the full loop having the radius of the minimum bend radius of the cable; and wherein linear segments are provided in loops greater in length than a full loop having the radius of the minimum bend radius of the cable. 
     In another embodiment, the cable management devices are provided on the substrate for containing one or more fiber loops, and are mounted to the substrate at a desired spacing to take into account the minimum bend radius of the stored cable. 
     In one embodiment, the cable management devices are provided with a base, and three uprights. Two uprights are on one side of the base, and one upright is on an opposite side of the base. When the cable management devices are mounted on the substrate for containing one or more fiber loops, they are mounted facing one another with the sides of the base with the one upright facing each other. Overhanging tabs on the ends of the uprights can be provided to assist with fiber retainment. 
     In another embodiment, the cable management devices are removably mounted to the substrate at a desired spacing to take into account the minimum bend radius of the cable. 
     This disclosure pertains to fiber optic cable storage devices, systems and methods used to store cable slack. The devices, systems and methods include a substrate, such as a tray in a telecommunication closures of the type found in the outside plant. Cable management devices are provided on the substrate for containing one or more fiber loops. Only two cable management devices are provided on the substrate facing one another. No outside fiber retainment devices are provided in a transverse direction relative to the two cable management devices. The two cable management devices allow for storage of fiber loops having a length defined by a cable in a full loop having the radius of the minimum bend radius of the cable up to and including a length twice as long as the full loop having the radius of the minimum bend radius of the cable. The two cable management devices allow for storage of fiber loops wherein no linear segments are defined by the full loop having the radius of the minimum bend radius of the cable; and wherein linear segments are provided in loops greater in length than a full loop having the radius of the minimum bend radius of the cable. The cable management devices are provided with a base, and three uprights. Two uprights are on one side of the base, and one upright is on an opposite side of the base. When the cable management devices are mounted on the substrate for containing one or more fiber loops, they are mounted facing one another with the sides of the base with the one upright facing each other. Overhanging tabs on the ends of the uprights can be provided to assist with fiber retainment. 
     Some telecommunications equipment uses tray systems to manage fiber optic cables and components. Some trays utilize fusion splice holder modules to organize and protect spliced optical fibers stored on the trays. These modules have also been integrated with optical components such as WDM and splitters. In one example, the CommScope FOSC line of splice trays are configured to receive and retain a splice holder module. 
     The trays, management devices, and component modules are provided with compatible attachment features that allow for the management devices and modules to be mounted to the trays. These trays can also include both the cable management devices for managing the fiber loops and the component modules, or those trays can be separate from the component modules on other trays. 
     A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the examples disclosed herein are based. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows: 
         FIG. 1  is a top schematic view showing an example embodiment of a cable storage device for managing different loops of fiber optic cable; 
         FIG. 1A  shows the device of  FIG. 1  for managing a first loop of fiber optic cable generally having a radius approximately equal to or greater than the minimum bend radius of the fiber optic cable; 
         FIG. 1B  shows the device of  FIG. 1 , with a second, larger loop of fiber optic cable generally including radiused ends approximately equal to or greater than the minimum bend radius of the fiber optic cable, interconnected by linear segments, but less than two times the length (double the circumference) of the fiber loop in  FIG. 1A ; 
         FIG. 1C  shows the device of  FIG. 1 , with a third, still larger loop of fiber optic cable having a similar set of radiused ends approximately equal to or greater than the minimum bend radius of the fiber optic cable of  FIG. 1B , and including longer linear segments interconnecting the radiused ends, wherein this loop is approximately double the circumference of the fiber loop in  FIG. 1A ; 
         FIG. 2  is a top view of one of the cable management devices of the cable storage device of  FIG. 1 ; 
         FIG. 3  is a bottom view of the cable management device of  FIG. 2 ; 
         FIG. 4  is a side view of the cable management device of  FIG. 2 ; 
         FIG. 4A  is a cross-sectional top view of the cable management device of  FIG. 2 , along lines  4 A- 4 A of  FIG. 4 ; 
         FIG. 5  is an end view of the cable management device of  FIG. 2 ; 
         FIG. 6  is a top perspective view of the cable management device of  FIG. 2 ; 
         FIG. 7  is a bottom perspective view of the cable management device of  FIG. 2 ; 
         FIG. 8  is a perspective view of cable storage device  FIG. 1 ; 
         FIG. 9  is an enlarged view of the cable storage device shown in  FIG. 1  showing the various representative loops of fiber optic cable; 
         FIG. 9A  shows fiber optic cables exiting and entering the cable storage device of  FIG. 9  for the smallest cable loop; 
         FIG. 9B  shows fiber optic cables entering and exiting the cable storage device of  FIG. 9  for the largest cable loop; 
         FIG. 9C  shows fiber optic cables entering and exiting the cable storage device of  FIG. 9  for the intermediate cable loop; 
         FIG. 9D  shows two full and one half partial loop of fiber optic cables stored; 
         FIG. 10  illustrates the same cable loops of  FIGS. 1, 1A, 1B, 1C , illustrating various radial dimensions and linear segment dimensions; 
         FIG. 11  illustrates the cable storage device of  FIG. 9 , showing one possible scenario that could arise if the cable loops are not allowed to have the shape of the largest cable loop; 
         FIG. 12  illustrates the cable storage device of  FIG. 9 , showing one possible scenario that could arise if only linear segments are created by the cable management devices; 
         FIG. 13  shows the cable storage device of  FIG. 1 , including the addition of a splice holder which can be utilized with the two cable management devices; and 
         FIG. 14  shows the cable storage device of  FIG. 1 , and attachment arrangements for attaching cable management devices and components to the tray base. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 to 8 , a telecommunications cable storage device  10  is shown. In one aspect, the telecommunications cable storage device  10  includes a tray  12  for storing fiber optic cables, and optionally telecommunications components. As shown, the tray  12  includes a base  14  and a circumferential sidewall  16  to define an interior volume  18 . To help retain fiber optic cables within the tray, extension tabs or members  20  can be provided. In the example shown, a plurality of extension tabs  20  are provided extending from the sidewall  16  over the interior volume  18  and in a direction parallel to the base  14 . 
     The tray  12  is also shown as including a plurality of attachment arrangements  30  arranged in an array extending the length of the tray  12  along the base  14 . The attachment arrangements  30  are configured to receive and retain cable management devices  40 . Various telecommunications components can also be provided, such as fiber optic adapters, splice holders, optical splitters, wavelength division multiplexers (WDM), and the like that are provided with an attachment arrangement compatible with the attachment arrangements  30 . 
     Cable management devices  40  in the illustrated embodiment are paired to store cable loops on a substrate, like the base  14  of the tray  12 . 
     Fiber optic slack management systems are needed in a variety of applications. One application is management of fiber optic slack required to splice two optical fibers together, and then stored and organized on trays. The tray systems contain routing paths to manage coils or loops of slack fiber and contain restrictive features to help the slack fiber maintain minimal bend radiuses (or above) to avoid fiber damage. Too many restrictions on an organizer system can create limitations on what lengths of slack can be stored. This can occur when a coil or loop of fiber is too large to fit the outer perimeter of the organizer, yet too small to make two complete loops around the inner perimeter. 
     The cable storage device  10  helps avoid needing specifically cut lengths so as to avoid unmanaged lengths of fiber that do not fit into any management device provided. These are sometimes referred to as “black out lengths” that result in not being able to properly store fibers in an organizer. 
     The devices, systems and methods by design and location on tray  12  provide fiber management and eliminate “black out lengths”. The cable management devices  40  are provided in pairs and face each other. The cable management devices include a quick connect features that allows them to snap into desired locations by a dove tail locking system that will be described below. Preferably the cable management devices  40  are identical. 
     The cable storage device  10  includes the ability to accommodate any length of fiber greater than one coil or loop. The cable storage device  10  is constructed in a modular manner to enable the minimum bend radius to be modified depending on the fiber optical cable being used and its associated minimum bend radius. 
       FIG. 1  shows an example embodiment of a cable storage device for managing different sized loops  202 ,  204 ,  206  of fiber optic cable  200 . The loops  202 ,  204 ,  206  are representative of single loops or a plurality of loops. The cables of each loop are connected to splices or other components on tray  12  or elsewhere. The cable  200  is stored as part of a connectivity solution where the loops of slack need storage. 
       FIG. 1A  shows the device  10  of  FIG. 1  for managing a first loop  202  of fiber optic cable  200  generally having a radius approximately equal to or greater than the minimum bend radius of the fiber optic cable. 
       FIG. 1B  shows the device  10  of  FIG. 1 , with a second, larger loop  204  of fiber optic cable generally including radiused ends  210  approximately equal to or greater than the minimum bend radius of the fiber optic cable, interconnected by linear segments  212 . 
       FIG. 1C  shows the device  10  of  FIG. 1 , with a third, still larger loop  206  of fiber optic cable having a similar set of radiused ends  210  approximately equal to or greater than the minimum bend radius of the fiber optic cable of  FIG. 1B , and including longer linear segments  214  interconnecting the radiused ends  210 . Loop  206  is approximately double the circumference of loop  202  in  FIG. 1A . 
     Fiber overlength or slack is stored within the cable storage device  10  with cable management devices  40  according to the following, with reference to  FIG. 10 : 
     Pn=Perimeter of Path n 
     Ln=Tangent Length of Path n 
     Rn=Minimum Bend Radius of Path n 
     P3=2*P1 (continuous range of slack storage from P1 to P3) 
     P1=2*Pi*R1 
     P3=2*(2*Pi*R1)=2*L3+(2*Pi*R3) 
     R3=R1 
     L3=P1*R1. 
     If: L3=Pi*R1; 
     Then: Pn can be any length&gt;P1.
 
If: Pn is between P1 and two times P3;
 
Then: maximum of two coils are required.
 
If: Pn is between P1 and three times P3;
 
Then: Maximum of three coils are required.
 
This trend continues for four times P3, etc.
 
Rn=10 mm, 15 mm, 20 mm, 30 mm, are some examples of minimum cable radius dimensions in the market.
 
P2 and L2 represent a cable loop  204  of a length between the minimum loop  202  and the maximum loop  206 .
 
     Given Rn is application dependent based on fiber type, such as 10 mm, 15 mm, 20 mm, 30 mm, tray  12  can be assembled and/or adjusted to efficiently accommodate any slack length. 
     In one embodiment as shown in  FIGS. 2-7 , the cable management devices  40  are provided with a base  42 , and three uprights  44 ,  46 ,  48 . Two uprights  44 ,  46  are on one side of the base  42 , and one upright  48  is on an opposite side of the base  42 . When the cable management devices  40  are mounted on the substrate for containing one or more fiber loops, they are mounted facing one another with the sides of the base with the one upright  48  facing each other. Overhanging tabs  50  on the ends of the uprights can be provided to assist with cable retainment. An inner trough area  52  is constructed to retain one or more fibers passing through the passage. The symmetrical design of each cable management device  40  eliminates left/right components. 
     The three pronged cable management device  40  provides a device, system and method capable of at least one of the following: 
     1. A fiber coil storage device that can adapt to various minimum bend diameters. 
     2. A fiber storage system to capture a full coil of fiber that is created by affixing two opposed three pronged cable managers to a substrate (for example, a tray).
         a. The two inboard vertical uprights of this configuration provide a full minimum diameter circular path with no flat edges at the extreme diametrically opposed tangencies. The tab created at the top of these inboard uprights prevents fibers from falling off in the minimum configuration.   b. The four outboard vertical uprights provide outward expansion containment as the required cable length to be stored grows (thus forming an oval) when a given length of fiber to be stored is greater than the circumference generated by the minimum diameter yet not yet a multiple of that same circumference. The tab created at the top of these outboard uprights prevents fibers from pushing off from outward expansion.   c. The device is constructed such that the minimum coil diameter can be adjusted and determined by the distance between the inboard uprights.       

     3. Although the inboard vertical as shown has a small flat surface the effect is negligible given the ratio of trough width (distance between the double and single tabs on a single clip) and foreseeable minimum coil diameters to be stored. Furthermore the flat surface could be completely eliminated if the upright was a semicircular round or otherwise curved post and the coils touched only at the tangencies.
         a. A device with anything more than one inboard post that forms the channel is not likely to achieve this optimal storage without significantly growing the trough width and thus quickly makes the device too large for many applications.       

     Cable management devices  40  and a substrate  12  allow for convenient management of fiber optic cable slack in a manner where the fibers are connected to other fibers or devices on both ends, and the slack is managed in loop shapes without having unmanaged segments that can interfere with other cables, get damaged, or create organization and use problems for the technician.  FIG. 8  shows the example cable loops  200  with the various tangent directions the cables leave the loops to extend to a splice or other component.  FIG. 1  also shows exemplary tangent directions for the cable  200  leaving the loops. 
     Cable management devices  40  and a substrate  12  help facilitate compact storage. In the case of outside plant closures, and in particular repair closures, overall size is desired to be as compact as possible such that they do not hinder placement. Therefore, for reduced internal slack storage space a technician needs to properly manage the short lengths of spliced fiber required in these small closures, such as with the illustrated cable management devices  40  and cable loops they manage. 
       FIG. 9  is an enlarged view of the cable storage device  10  shown in  FIG. 1  showing the various representative loops of fiber optic cable.  FIG. 9A  shows fiber optic cables  200  exiting and entering the cable storage device  10  of  FIG. 9  for the smallest cable loop  202 .  FIG. 9B  shows fiber optic cables  200  entering and exiting the cable storage device  10  of  FIG. 9  for the largest cable loop  206 .  FIG. 9C  shows fiber optic cables  200  entering and exiting the cable storage device  10  of  FIG. 9  for the intermediate cable loop  204 . 
     Typically fibers come off the loops at the most distant points from the center as found in  FIG. 9B . These tangents are also illustrative of the minimum desired width of a walled tray.  FIGS. 9A and 9C  are to be noted as being possible, but are not likely typical. 
       FIG. 9D  shows two full and one half partial loop of fiber optic cables  200  stored. In this application the half loop has been assumed as a method of entry and exit of the fiber into the storage coil and has been assumed to be fixed regardless of additional slack requirements. For optimal storage the width of this area must be at least this dimension to allow for any length of fiber greater than one and a half circumferences of the minimum sized loop to be placed. 
       FIG. 11  illustrates the cable storage device  10  of  FIG. 9 , showing one possible scenario that could arise if the cable loops, for example loop  206 ,  208  are not allowed to have the shape of the largest cable loop. Lines  180 ,  182  represent sidewalls of a tray that, if present for the cable  200 , could create unmanaged black out lengths for any cable loops (such as loop  208 ) that extend outwardly past lines  180 ,  182 . The reason is that loop  208  is not long enough to form two smaller loops  202 . Therefore, an unmanaged loop  208  (having at least some unmanaged portions) could create problems for the technician or for keeping the fiber protected and organized. One solution could be to add more structures, but this is a less preferred manner of keeping the cable management devices simple and easy to access. 
       FIG. 12  illustrates the cable storage device  10  of  FIG. 9 , showing one possible scenario that could arise if only linear segments are created by the cable management devices. The longer the lengths, the more fiber storage could be limited. Lines  186 ,  188  represent the minimum linear cable routing paths of a hypothetical cable management device  40 ′ of a tray that, if present for the cable  200 , could create unmanaged black out lengths for any cable loops (such as loop  210 ) that must extend linearly between lines  186 ,  188 . The reason is that loop  210  is not long enough to form a full loop while also extending past lines  186 ,  188 . Therefore, an unmanaged loop  210  (having at least some unmanaged portions) could create problems for the technician or for keeping the fiber protected and organized. One solution could be to add more structures, but this is a less preferred manner of keeping the cable management devices simple and easy to access. 
     As shown in  FIG. 13 , a tray  12  is shown with a fiber optic splice holder module  140  mounted to tray  12 . The cable management devices  40  can be positioned as desired on tray  12  for managing fiber optic cables extending to and from the splices of the splice holders  140 . Cable management devices  40  have generally planar exterior walls. An inner trough area is constructed to retain one or more fibers passing through the interior passage. Similarly, splice holders  140  have generally planar vertical walls to allow for side by side placement with other splice holder modules  140 , other modules, or cable management devices  40  as in  FIG. 13 . 
     As also shown in  FIG. 13 , tray  12  is shown with a fiber optic splice  160  in fiber optic splice holder module  140  mounted to tray  12 . Cable segments  220 ,  222  extend from cable loop  206  to be spliced at splice  160 . Cable segments  224 ,  226  extend from loop  206  to leave tray  12 . For example, cable segment  224  can be a fiber feeder cable and cable segment  226  can be a fiber drop cable, both extending to and from a closure structure protecting tray  12  in the interior of the closure. 
     Other telecommunications components can be mounted to tray  12  including splitter modules. The splitter modules can be mounted instead of splice holder modules  140  or in combination with splice holder modules  140 . 
     The trays  12  and devices  40  and modules  140  are provided with compatible attachment features  30 ,  110  that allow for the devices/modules to be mounted to the trays. In one aspect, each attachment arrangement  30  of the tray  12  includes a pair of connection points  32 ,  34 . (See  FIG. 14 .) The first connection point  32  is configured as a t-shaped opening in the base  14  with a first open portion  32   a  and a second open portion  32   b . The second connection point  34 , arranged oppositely from the first connection point  32 , is configured with a first opening  34   a  into which a cantilevered tab  34   b  extends such that open side slots  34   c  exist on each side of the cantilevered tab  34   b . Similarly constructed attachment arrangements for use with interconnecting telecommunications components are shown and described in Patent Cooperation Treaty (PCT) Application Serial Number PCT/US2019/17904, filed on Feb. 13, 2019, the entirety of which is incorporated by reference herein; Patent Cooperation Treaty (PCT) Application Serial Number PCT/US2019/028245, filed on Apr. 19, 2019, the entirety of which is incorporated by reference herein; and U.S. Provisional Patent Application Ser. No. 62/824,824, filed on Mar. 27, 2019, the entirety of which is incorporated by reference herein. 
     The attachment arrangement  110  of the cable management device  40  is configured with an attachment feature  112 , including a pair of oppositely arranged interlock structures  114  and a pair of ramp structures  116 . Accordingly, the base  42  can be attached to a pair of attachment arrangements  30  of the tray  12 . It is also noted that the pairs of interlock and ramped structures  114 ,  116  are symmetrically arranged such that the cable management device  40  is symmetrical about a longitudinal axis. With such a configuration, the cable management device  40  can be easily mounted to the tray  12  in two orientations. 
     As shown, each of the ramp structures  116  includes a ramped surface  116   a  and a stop surface  116   b . As shown, each of the interlock structures  114  includes a pair of angled or sloped surfaces  114   a  that form a dovetail shape, thereby enabling the interlock structures  114  to form a tight connection against the tray  12 . As configured, the attachment arrangement  110  can be connected to the attachment arrangement  30  by aligning the main body bottom side  102  with the base  14  such that the interlock structures  114  and ramp structures  116  drop into the openings  32   a ,  32   b  of the connection point  32  and the opening  34   a  of the connection point  34 . From this position, the base  42  can be displaced laterally in a direction towards the cantilevered tab  34   b  until the tab snaps over the ramped surface  116   a  and abuts the stop surface  116   b . In this position, the attachment arrangements  110 ,  42  are fully interconnected. The U.S. 62/824,824, PCT/US2019/17904, and PCT/US2019/028245 applications describe a generally similar connection arrangement between two components. To detach the cable management device  40  from the tray  12 , the cantilevered tabs  34   b  can be disengaged by depressing them away from the base  42  and tray  12 . 
     The example attachment device and method described above is provided by way of illustration only and should not be construed to limit the scope of the present disclosure. 
     Those skilled in the art will readily recognize various modifications and changes that may be made with respect to the examples and applications illustrated and described herein without departing from the true spirit and scope of the present disclosure.