System for organizing optical fibers

A fiber storage system includes one or more splice holder assemblies and one or more fiber routing devices. The splice holder assembly has a sleeve in the shape of a closed figure having a plurality of substantially flat sides or a ring. The sleeve has a plurality of holes on its sides. At least one splice holder is mounted on the side walls of the sleeve, near one or more of the holes. The fiber routing device includes a sleeve in the shape of a closed figure having a plurality of substantially flat sides or a ring, and a plurality of troughs attached to an outer surface of the top portion of the sleeve. The splice holder assemblies may be stacked on top of each other, or on top of the fiber routing devices. The fiber routing devices may be stacked on top of each other, or on top of the splice holder assemblies. The stack of splice holder assemblies and fiber routing devices form a pedestal for routing and terminating optical fibers. The fibers can be routed outside of the pedestal between splice holders at different levels, and between splice holders on different sides of the pedestal.

FIELD OF THE INVENTION
 The present invention relates to telecommunications equipment generally,
 and more specifically to enclosures for optical fibers.
 DESCRIPTION OF THE RELATED ART
 Optical fiber communication networks have gained wide acceptance in place
 of the use of electrical cable systems, due to the significantly enhanced
 bandwidth capabilities of optical fiber and its immunity to
 electromagnetic and radiomagnetic interference. Very significant
 advantages are achievable by the use of optical fiber rather than
 electrical conduction media. Nevertheless, a continuing problem with the
 deployment of optical fiber systems is providing a method to terminate
 optical fiber cables so as to make electrical or optical connections to
 fibers within the cables while providing adequate environmental protection
 and allowing for easy installation. U.S. Pat. No. 5,069,516 to Kohy et al.
 and U.S. Pat. No. 5,396,575 to Hayward et al. are expressly incorporated
 by reference herein in their entireties for their teachings on sealed
 fiber enclosures.
 U.S. Pat. Nos. 4,913,522, 5,155,794 and 5,602,954 to Nolf et al., and U.S.
 Pat. No. 5,249,253 to Franckx et al. are expressly incorporated by
 reference herein in their entireties. These patents describe an enclosure
 for a butt splice of optical fiber cables.
 The systems described in the above mentioned patents include a plurality of
 hinged fiber splice trays. To use a selected one of the trays, it is
 necessary to pivot any tray above the selected tray. A separate apparatus
 is described for selectively exposing respective trays. The apparatus is
 hinged so that a bar can move to allow selected trays to be held in an
 upright position for working on those trays.
 The above described apparatus for selectively exposing trays is bulky and
 cumbersome to use. Other, more convenient methods have been sought to
 allow one of the splice trays to be selectively exposed for installation
 or repair of a splice. In one example, a clip has been inserted in the
 hinged corner between the exposed horizontal tray and the adjacent
 (unexposed) vertical tray immediately above the exposed tray. The clip
 prevents the adjacent vertical tray from pivoting downward about its
 hinge, maintaining the horizontal tray exposed. Although the clip is
 compact, it is easily lost. Further, if the worker forgets to remove the
 clip when the work is completed, either the clip or the trays, or both,
 may be damaged when the vertical trays are lowered.
 In addition, the above described tray systems are designed to accommodate a
 large number of fibers, and may not be economically practical for
 configurations that (at least initially) do not involve a large number of
 fibers.
 An improved and economical fiber organizer system is desired.
 SUMMARY OF THE INVENTION
 One aspect of the present invention is a device for routing optical fiber,
 including a sleeve and a plurality of troughs. The sleeve has the shape of
 either: (a) a closed figure having a plurality of substantially flat sides
 or (b) a ring. The sleeve has a top portion, a bottom portion, and a
 shoulder connecting the top and bottom portions. One of the top portion
 and the bottom portion has an inner dimension that is larger than the
 outer dimension of a corresponding location on the other of the top and
 bottom portions. The plurality of troughs are attached to an outer surface
 of the sleeve.
 Another aspect of the invention is a fiber storage system, including at
 least one splice holder assembly and at least one fiber routing device.
 The splice holder assembly includes a sleeve in the shape of a closed
 figure having a plurality of substantially flat sides or a ring. The
 sleeve has at least one hole in at least one side thereof. The splice
 holder assembly also includes at least one splice holder mounted on the
 side wall of the sleeve, near the hole. The fiber routing device includes
 a sleeve in the shape of a closed figure having a plurality of
 substantially flat sides or a ring, and a plurality of troughs attached to
 an outer surface of the sleeve. At least one of the splice holder assembly
 or the fiber routing device is stackable on the other one of the splice
 holder assembly and the fiber routing device.
 Still another aspect of the invention is a method for routing fiber,
 including the steps of: (a) providing first and second splice holders and
 at least one trough, the trough being on a different level from either one
 of the first and second splice holders; and (b) routing a fiber from the
 first splice holder to the second splice holder by way of the at least one
 trough.
 The above and other features of the present invention will be better
 understood from the following detailed description of the exemplary
 embodiment of the invention which is provided in connection with the
 accompanying drawings.

DETAILED DESCRIPTION
 FIG. 1 is an elevation view of a fiber storage system 110 including a fiber
 routing device 10 according to the present invention. The system 110
 includes at least one splice holder assembly 20 and at least one fiber
 routing device 10. The splice holder assemblies 20 and fiber routing
 devices 10 are stacked together to form a pedestal 100. The exemplary
 pedestal 100 has two splice holder assemblies 20 and three fiber routing
 devices 10, but pedestals are contemplated including any combination of
 one or more splice holder assemblies 20 and one or more fiber routing
 devices 10.
 As shown in FIG. 1, it is possible to stack a splice holder assembly 20
 beneath or on top of a fiber routing device 10. Although not shown, two
 splice holder assemblies 20 may be stacked atop one another without an
 intervening fiber routing device 10. Nevertheless, to improve routing
 flexibility, it may be preferred to have one or more fiber routing devices
 10 between any pair of splice holder assemblies 20. As shown in the
 exemplary embodiment, a fiber routing device 10 may be beneath or on top
 of a splice holder assembly 20 or another fiber routing device 10.
 The system 110 further includes an enclosure. The enclosure has a base 30
 and a cover 40. The base 30 is positioned beneath a bottommost splice
 holder assembly 20 or fiber routing device 10. The bottom flange 33 of
 base 30 is fastened (e.g., using bolts) to a suitably stable surface, such
 as concrete. The cover 40 engages the base plate 31 to form a sealed
 enclosure around the pedestal 100. Preferably, a gasket or seal 41 is used
 to prevent ingress of moisture.
 FIGS. 2-4 show the exemplary fiber routing device 10. The fiber routing
 device 10 has a sleeve in the shape of a closed figure having a plurality
 of substantially flat sides or a ring. The sleeve of the fiber routing
 device 10 has a top portion 11, a bottom portion 12, and a shoulder 13
 connecting the top and bottom portions. The top portion 11 has an inner
 dimension ID that is larger than the outer dimension OD of a corresponding
 location on the bottom portion 12.
 Although the exemplary sleeve 11, 12, 13 has six sides 19 (a hexagon), the
 sleeve may have any number of three or more sides. For a top portion 11
 having at least three flat sides 19, the bottom portion 12 has at least
 three flat sides 18 aligned with the sides 19 of the top portion.
 Alternatively, the sleeve may be a circular or elliptical ring having a
 smaller outer diameter (male) portion and a larger inner diameter (female)
 portion sized to receive the male portion of a similar sleeve.
 The sleeve 11, 12, 13 may be formed from sheet metal (e.g., aluminum or
 steel) or plastic. Exemplary plastics may include, but are not limited to,
 polyvinyl chloride (PVC), acrylonitrile-butadiene-styrene (ABS), and
 polycarbonate.
 At least one of the flat sides 19 of the top portion 11 has at least one
 trough 14 attached thereto. In the exemplary embodiment, each of the flat
 sides 19 of the top portion 11 has two mounting holes 15. Each mounting
 hole 15 is capable of having a respective trough 14 attached thereto. Each
 side 19 of the sleeve may have any number of trough mounting holes 15 (or
 other mounting means), and it is not required for each side 19 to have the
 same number of holes (or other mounting means).
 The troughs 14 are best seen in FIG. 2. The plurality of troughs 14 are
 detachably mounted on the holes 15 of the top portion 11 of the sleeve of
 the fiber routing device 10. The exemplary troughs are detachably mounted
 using latches 14c. Other fasteners (e.g., screws or nuts and bolts) or an
 adhesive (which may be an epoxy) may be used to attach the troughs.
 Alternatively, the device 10 may be consist of a single piece; that is,
 the troughs 14 may be integrally formed from the same piece of material as
 the sleeve 12, 13, 14.
 Each trough has the general configuration of a large open loop with two
 overlapping ends 14a and 14b. The troughs 14 are preferably made of
 plastic, such as PVC, ABS or polycarbonate. The loops of the troughs 14
 are much longer than the width of the troughs, so that it is easy to
 deflect the ends 14a and 14b. To route a fiber through one of the troughs
 14, one can merely press lightly on the inner end 14a to form an opening
 large enough to receive a fiber, and insert the fiber sideways into the
 loop. To remove a fiber from a trough 14, one can pull lightly on the
 outer end 14b to form an opening large enough to pass the fiber, and
 remove the fiber sideways through the opening.
 FIG. 5 shows an exemplary splice holder assembly 20. Assembly 20 has a
 sleeve 21 in the shape of a closed figure having a plurality of
 substantially flat sides or a ring. As in the case of the fiber routing
 device 10, the sleeve 21 may have three or more flat sides, or may be
 circular or elliptical. The sleeve 21 has a female (top) portion 25
 capable of receiving the bottom portion 12 of the fiber routing device 10,
 and a male (bottom) portion 26 capable of fitting into the top portion 11
 of the device 10.
 Preferably, top portion 25 has the same cross section (i.e., number of
 sides and dimensions) as the top portion 11 of device 10, and bottom
 portion 26 has the same cross section as the bottom portion 12 of device
 10. This allows fiber routing devices 10 and splice holder assemblies 20
 to be stacked upon each other in any desired order or configuration.
 So long as the top and bottom portions 11, 12, 25 and 26 are compatible,
 the cross section of the central portion of the sleeve 21 may differ from
 the cross section of the top and bottom portions 25 and 26. For example,
 it is possible to have hexagonal top and bottom portions 25, 26 with an
 approximately circular central portion therebetween. Similarly, the top
 and bottom portions 25, 26 may be circular, with a hexagonal central
 portion therebetween. One of ordinary skill can readily design a
 transition between two portions having different cross sections.
 The sleeve 21 has at least one hole 22 in at least one side thereof. If the
 sleeve has a polygonal cross section, the hole 22 may be at the vertex
 where two sides meet (straddling two sides), or may be closer to the
 middle of one of the sides. The exemplary assembly 20 has a plurality of
 holes 22. The hole 22 may have a variety of shapes. A hole 22 having an
 elongated shape is advantageous because it allows fibers emerging from
 inside the pedestal 100 to be routed up, down or horizontally without
 interference. The holes 22 should have rounded corners, or a circular,
 elliptical or oval shape, so as to avoid damaging the fibers when the
 fibers contact the edge of the holes. The holes 22 may be evenly spaced
 around the perimeter of the sleeve 21, or they may be unevenly spaced. The
 holes 22 may be cut out from, or molded into, the sleeve 21 before
 installation, or the holes may be cut or punched out as needed. For
 example, the sleeve 21 may be provided with a plurality of indentations to
 facilitate punching out the holes 22 as they are required.
 The splice holder assembly 20 has at least one splice holder 24 mounted on
 the side wall of the sleeve 21, near the hole 22. If space permits, more
 than one splice holder 24 may be arranged in a horizontal row or a
 vertical column between the holes 22.
 A strain relief mechanism is provided. The strain relief mechanism may
 include one or more strain relief devices. In the exemplary embodiment, a
 pair of conventional fiber storage barrels or spools 23 provide strain
 relief. For example, each of two fibers to be spliced together in the
 splice holder 24 may be wound once around the fiber storage barrels to
 provide strain relief before routing the bulk of the fiber slack to
 another part of the system. Alternatively, other conventional strain
 relief mechanisms may be used.
 FIG. 6 is a top plan view of the base 30. Base 30 has at least one side
 wall 32 connecting the mounting flange 33 to the base plate 31. A hollow
 35 is formed inside the side walls 32, for routing fibers from the ground
 up to the splice holder assemblies 20 and fiber routing devices 10.
 Preferably, the base 30 is formed of a strong, corrosion resistant
 material, such as stainless steel or other metal. Strength is desired to
 protect the assembly in the event that it is kicked. Although the side
 wall 32 may have any height, it is preferred that the side wall is high
 enough to raise the base plate 31 above the expected level of water during
 flooding for the location at which the system 110 is to be installed.
 Referring again to FIG. 1, a method of routing fiber is now described. The
 method includes the steps of: (a) providing first and second splice
 holders 24 and at least one trough 14, the trough being on a different
 level from either one of the first and second splice holders 24; and (b)
 routing a fiber 52 from the first splice holder 24 to the second splice
 holder 24 by way of the at least one trough 14.
 FIG. 1 shows only three exemplary fibers 51, 52 and 53 for ease of viewing.
 Any number of fibers may be accommodated by a pedestal 100. Fiber 51 has a
 top portion 51a that is routed inside of the pedestal 100, and winds (at
 least once) around barrel 23 for strain relief. The portion 51b of fiber
 51 emerging from the barrel 23 is spliced to the top portion 52a of fiber
 52 at the top splice holder 24.
 Fiber 53 has a lower portion 53b that emerges from the ground through base
 30 and is routed out through hole 22. Fiber 53 is wound around the lower
 barrel 23 for strain relief, and the portion 53a of fiber 53 emerging from
 the barrel 23 is spliced to the bottom portion 52d of fiber 52 at the
 bottom splice holder 24.
 Fiber 52 is routed between the top and bottom splice holders 24 and is
 spliced at its top and bottom ends to fibers 51 and 53, respectively. For
 ease of viewing, FIG. 1 shows a fiber 52 that is routed between two splice
 holders 24 on the same front side of the pedestal 100. However, the
 configuration and method according to the invention can just as easily
 allow fibers to be routed between holes 22 and/or splice holders 24 on
 different sides of the pedestal 100. Thus, although fiber 52 is shown
 extending 360 degrees around pedestal 100, given splice holders on all six
 sides of assembly 20, the fiber 52 could readily be extended through any
 of the angles 0, 60, 120, 180, 240, 300 or 360 around the pedestal. In
 general, the fiber can be routed through any angle for which routing
 troughs 14 are provided.
 The top portion 52a of fiber 52 is routed from the top splice holder 24 to
 the barrel 23, and wound around the barrel for strain relief. Portion 52b
 of fiber 52 is routed through one or more of the troughs 14, until the
 fiber emerges at a desired side of the pedestal 100, as shown by fiber
 portion 52c. Fiber portion 52c is wound around barrel 23 for strain
 relief. The lower portion 52d of fiber 52 emerging from the barrel 23 is
 then routed to the bottom splice holder 23, where it is spliced to fiber
 53.
 If a fiber is to be routed between two splice holders 24 on the same side
 of the pedestal 100, the fiber can be routed 360 degrees by way of the
 fiber routing device 10 as shown. However, it is also possible to route
 the fiber directly between the two central barrels 23 without routing the
 fiber through the troughs 14.
 The troughs 14 provide great flexibility in routing fibers between splice
 holders 24 located at different vertical and/or tangential
 (circumferential) positions. If all fiber routing were performed at the
 interior of the pedestal 100, it would be difficult to locate any specific
 fiber, and the fibers would quickly become entangled as the number of
 fibers increases. The troughs 14 allow the fiber routing to be performed
 on the exterior of the pedestal 100, where the fibers are easily visible.
 The exemplary system 110 has many advantages. The system is modular and
 expandable. All of the splice holders 24, barrels 23 and troughs 14 are
 exposed and within reach. There are no moving parts, so the system 110 is
 easy to use.
 The method may include stacking one of the group consisting of a splice
 holder assembly 20 and a fiber routing device 10 on the other one of the
 group consisting of the splice holder assembly and the fiber routing
 device. In a simple configuration, there may only be one or two splice
 holder assemblies 20 and one or two fiber routing devices 10. The method
 may include forming a stack that includes a plurality of splice holder
 assemblies 20 and a plurality of fiber routing devices 10 as more fibers
 are installed. The device 10 and assembly 20 may be of the type described
 above with reference to FIGS. 2-5. The method may also include the step of
 attaching the at least one trough 14 to the fiber routing device 10.
 To grow the pedestal 100 at any time, any desired fiber routing devices 10
 and/or splice holder assemblies 20 can be added. If necessary, cover 40
 can be replaced with a taller cover to accommodate the enlarged pedestal.
 Although the exemplary embodiment is a modular system, it is contemplated
 that a fiber routing device according to the invention may also
 incorporate the splice holder function. Thus, one can form a fixed
 configuration pedestal (not shown) in which a single unitary fiber routing
 device incorporates the troughs 14 at one level and holes 22, barrels 23
 and splice holders 24 at another level. Such a fixed configuration could
 perform the same fiber organizing and routing functions as the exemplary
 pedestal 100, but would not be as readily re-configurable (It would still
 be possible to stack more devices 10 and assemblies 20 on top of the fixed
 configuration pedestal to increase the number of levels of splice holder
 assemblies or fiber routing devices).
 Although the exemplary pedestal 100 has splice holder assemblies 20 and
 fiber routing devices 10 that are wider (female) at the top and narrower
 (male) at the bottom, these subassemblies 10, 20 may each be formed wider
 (female) at the bottom than at the top. In this variation, each device 10
 or assembly 20 would be placed over (rather than inside) the device or
 assembly beneath it. That is, the male sleeve portions 12, 26 may be
 positioned at the top of device 10 and assembly 20, respectively.
 Although the invention has been described in terms of exemplary
 embodiments, it is not limited thereto. Rather, the appended claim should
 be construed broadly, to include other variants and embodiments of the
 invention which may be made by those skilled in the art without departing
 from the scope and range of equivalents of the invention.