BACKGROUND
1. Field of the Invention
The present invention relates to an apparatus and method for managing flexible lines or flexible elongate elements such as a wire, tube, individual fiber, ribbon fiber, or cable with fixed ends.
2. Related Art
When terminating optical connectors or other devices to optical fiber cables, it is necessary to splice the optical fibers together. Since excess fiber length is needed to perform fusion splicing, an excess of fiber is left between the devices after splicing. The excess fiber length has to be managed. Since both ends of the fiber are fixed or inaccessible, coiling the fiber is difficult and potentially damaging due to the torque which builds up with each loop. Fiber is also susceptible to optical measurement losses or shortened life if it is wound to a radius smaller than the minimum fiber bend radius. It is known to wind fiber in a figure eight pattern, relieving the torque as you wind first in one direction then in the other. One known fiber management system is two spaced, coplanar spools between the fixed fiber ends. Fiber is wound in a figure eight pattern on the spools, while maintaining a radius greater than the minimum fiber bend radius. The two side-by-side spools take up additional space between the optical devices.
Similar problems are encountered in managing lengths of other lines such as flexible wires or tubes with fixed ends. Coiling such lines can also be difficult due to torque build up.
Therefore, what is needed is an apparatus and method that reduces or overcomes these significant problems found in the known systems as described above.
SUMMARY
Embodiments described herein provide for an apparatus and method for managing flexible lines or flexible elongate elements between fixed ends or points in the line to handle any slack in the line between the fixed ends.
According to one aspect, apparatus for managing flexible lines is provided, which comprises a folding device having first spool member, a second spool member, and a flexible or foldable joint or hinge connecting the spool members which allows the spool members to be folded between an open condition in which the spool members are in co-planar, side by side positions and a closed, folded condition in which the spool members are folded towards one another about the joint until they are aligned and substantially face-to-face, each spool member having a groove extending in an at least substantially continuous loop which receives successive windings of a line or elongate element as it is wound in a figure eight pattern between the two spool members with the device in an open condition.
In a first embodiment, each spool member has opposite first and second faces and an outwardly facing winding channel or groove extending around at least a major part of the peripheral edge of the spool member, the hinge extending between the first faces of the spool members which are directed inwardly when the spool is folded, whereby the annular channels are located on the outside of the folded spool assembly in the folded condition. The spool members may have central openings which are aligned in the folded condition. In a second, alternative embodiment, each spool member is a flat, ring-shaped member having opposite first and second faces and a winding groove on the first face for receiving windings of a flexible line or flexible elongate element. In the second embodiment, the winding grooves are arranged to face outwardly in the folded flat condition.
The apparatus may be used to manage any type of flexible elongate line or element, such as optical fibers, electrical wires, cables, ropes, flexible tubes or hoses, threads, or the like, with suitable adjustment of the winding groove width and diameter on each spool. The material of the spool may also be varied, depending on the material of elongate line to be managed. In one embodiment, the flexible elongate elements comprise one or more individual optical fibers or ribbon fibers. Although parts of the following description refer to individual or ribbon fibers as the flexible line or elongate element, other types of flexible elongate element may also be managed in an equivalent manner to that described below. Where the flexible line is optical fiber, the first embodiment above is suitable for managing one or more individual fibers or for managing ribbon fiber. The second embodiment may be used to for managing a thinner elongate element such as an individual optical fiber.
In one embodiment, a fiber management apparatus is provided in which the hinge comprises two spaced hinge portions connecting the spool members with a gap between the hinge portions providing a cross over area for windings of fiber from one spool member to the other. The annular winding channels or grooves may have cut-outs aligned with the gap. The gap or cross over area provides a clearance for fiber or other flexible line in the cross over area when the fiber is wound in a figure eight pattern with the device in an open condition, allowing the fiber to bend at the cross over area while the device is folded. Fiber is wound first in one direction around the first spool, then extended over the gap onto the second spool, and wound in the opposite direction around the second spool before extending over the gap and crossing over the previous length of fiber in the gap, then back onto the first spool, where it is wound again in the first winding direction. This process is repeated until most of the slack is taken up, at which point the two spool members are folded together about the hinge portions into the folded, closed condition. Any remaining free fiber is then wound into the appropriate spool member. In the first embodiment of the apparatus, the inner faces of the spool members face one another and the wound fibers are outside the folded faces. The channels in which the fibers are wound are outside the hinge in the folded condition and fibers in the gap or cross over area tend to be held away from the opposing inner faces of the spool member as the devices is folded. If the device were folded with the winding channels on the inside of the fold, there is a greater risk of fibers in the cross over area contacting the spool members during folding.
In both the first and second embodiments of the apparatus, the hinge portions may be formed integrally with the spool members or may be formed separately and then secured to the respective spool members by any suitable fastener mechanism. Holes may be provided in opposite rims of each spool member to receive tie wrap for keeping wound fiber in place on the spool member. The tie wrap can also extend between the spool members so as to secure the spool members in the folded condition.
In another embodiment, the apparatus further comprises a mounting device for holding one or more folding devices in the folded condition. In one embodiment, the folding device has a central opening in the folded condition and the mounting device comprises a mounting base and a hub extending from one face of the base which extends through the opening in at least one folding device in the folded condition. The hub may have flexible fingers which are compressed as the folding device is pushed over the hub, and which have an indent to receive one or more folding devices in a storage position in which the fingers spring back to hold the device on the hub. The mounting base may be mounted on any suitable structure within a dedicated enclosure for the fiber or other flexible lines or flexible elongate elements.
In the case of optical fiber management, the mounting base may be attached to one or more stand off rods between optical devices into which the optical fibers extend.
According to another aspect, a method of managing excess length of a flexible line or elongate element between fixed points on the line is provided, which comprises positioning first and second spool members which are connected together by a hinge in a coplanar, open condition, winding a length of the line in a first direction around a groove in the first spool member, extending the line over a cross over area between the spool members, winding a subsequent length of the line in a second direction around a groove in the second spool member, extending the line back over the cross-over area between the spool members to form a figure eight pattern, repeating the preceding winding steps to form successive figure eights until at least a major part of the excess length of line is taken up by the windings on the spool members, and folding the spool members together about the hinge into a folded, closed condition. In one embodiment, the spool members are folded before a final winding is made, and the final winding is made about the appropriate groove after the spool members are folded together. In one embodiment, the flexible line may be one or more individual optical fibers or an optical ribbon fiber.
Other features and advantages of the present invention will become more readily apparent to those of ordinary skill in the art after reviewing the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The details of the present invention, both as to its structure and operation, may be gleaned in part by study of the accompanying drawings, in which like reference numerals refer to like parts, and in which:
FIG. 1 is a perspective view of a prior art fiber management apparatus positioned between two fiber optic devices;
FIG. 2A is a perspective view of one embodiment of a fiber management apparatus comprising a folding dual spool device, with the device in an open condition;
FIG. 2B is a perspective view of the device of FIG. 2A in a partially folded condition;
FIG. 2C is a perspective view of the device of FIGS. 2A and 2B in a more folded condition;
FIG. 2D is a perspective view of the device of FIGS. 2A to 2C in a completely folded, closed condition;
FIG. 3 is a schematic perspective view of the device of FIGS. 2A to 2D in the open condition of FIG. 2A which schematically indicates the winding of fiber on the two spools of the folding device with the fiber shown outside the winding grooves for illustration purposes;
FIG. 4A is a front elevation view of the device of FIGS. 2 and 3 in a folded, closed condition with fiber wound on the device;
FIG. 4B is a cross-sectional view illustrating a modified dual spool folding device in the position of FIG. 4A, illustrating a modified winding groove or channel shape;
FIG. 5 is a perspective view illustrating one embodiment of a fiber management apparatus comprising a folding dual spool device as in FIGS. 2 to 4A and a mounting device for the folding dual spool device of FIGS. 2 to 4A, with the dual spool device in the closed position of FIG. 2D and positioned in alignment with the mounting device.
FIG. 6 is a perspective view similar to FIG. 5 illustrating several folding dual spool devices positioned on the mounting device;
FIG. 7 is a perspective view illustrating the apparatus of FIGS. 5 and 6 positioned between two optical devices;
FIG. 8A is a perspective view illustrating another embodiment of a fiber management apparatus comprising a modified folding dual spool device in an open condition;
FIG. 8B is a perspective view of the device of FIG. 8A in a partially folded condition;
FIG. 9 is a perspective view of the device of FIGS. 8A and 8B in the open condition illustrating fiber wound on and between the spools in a figure eight pattern;
FIG. 10 is a front elevation view of the device of FIGS. 8 and 9 in a folded, closed position with fiber wound on the device; and
FIG. 11 is a schematic front elevation view of the fiber management apparatus of FIGS. 2 to 7 positioned between two fixed fiber points at two optical devices, illustrating parameters for calculating a desired total spliced fiber length prior to splicing and winding of the fiber.
DETAILED DESCRIPTION
Certain embodiments as disclosed herein provide for an apparatus and method for managing flexible lines or flexible elongate elements having fixed ends. For example, one apparatus and method as disclosed herein allows for managing excess of fiber between fixed ends or points on the fiber produced when terminating various devices to optical fiber cables.
After reading this description it will become apparent to one skilled in the art how to implement the invention in various alternative embodiments and alternative applications. However, although various embodiments of the present invention are described herein, it is understood that these embodiments are presented by way of example only, and not limitation. As such, this detailed description of various alternative embodiments should not be construed to limit the scope or breadth of the present invention as set forth in the appended claims.
In the following description, embodiments of an apparatus and method for managing fibers such as optical fibers are described, but the described apparatus and methods may alternatively be used for managing other types of flexible line or flexible elongate elements, such as electrical or other flexible wires, cables, ropes, flexible tubes or hoses, threads, or the like. In the case of optical fiber, the fiber may be one or more individual optical fibers or a ribbonized fiber (ribbon fiber). Ribbon fiber contains multiple fibers in a ribbon-like form. The management apparatus and methods for flexible elongate elements or lines other than fibers may be identical to those described in the embodiments below, with appropriate adjustment of the scale and material of the apparatus to accommodate flexible elongate elements of different sizes and materials.
The term “spool” as used in this application means a device on which a flexible elongate element can be wound or spooled. Although the spools illustrated in the drawings and described below are round, in other embodiments the spools may have other continuous loop shapes such as elliptical, oval, polygonal, or the like.
The term “hinge” as used in this application means a flexible or foldable joint or connection that allows the turning or pivoting of a part, and may be a so-called “living hinge” of bendable material which is sufficiently flexible to allow pivoting, or a physical pivot or hinge joint.
FIG. 1 illustrates a prior art fiber management apparatus 10 comprising two spools 12,13 positioned in a side-by-side, coplanar arrangement and secured to a stand-off rod 14 between two fiber optic devices 16,18 such as a connector shell and a cable termination housing. Excess of fiber, after the fiber pigtails from each device have been spliced, is managed by winding in a figure eight pattern around the two spools 12, 13. It can be seen that this arrangement takes up a significant amount of space.
FIGS. 2 to 4 illustrate a first embodiment of a fiber management apparatus comprising a folding dual spool device 20, with FIGS. 2A to 2D illustrating steps in folding the device 20 between an open condition (FIG. 2A) and a folded, closed condition (FIG. 2D). Device 20 comprises first and second spool members 22, 24 connected together by a hinge comprising two spaced hinge portions 25, 26. In the illustrated embodiment, the hinge portions are formed integrally with the two spool members and may comprise flexible hinges for folding and unfolding the device. In this case, the entire device is formed integrally out of a material which is flexible when sufficiently thin, such as plastic, and the hinges are formed by reduced thickness portions or indents in the material which can bend, i.e. so-called “living hinges”. However, in alternative embodiments, a separate hinge may be provided and suitably fastened or connected between the two spool members. In either case, the hinge comprises spaced hinge portions 25, 26 with a gap or space 28 between the hinge portions. The hinge portions 25, 26 form a central fold line about which the spool members can be folded.
Each spool member is generally ring-shaped or annular with a central opening 30, a first or inner face 32, a second or outer face 34, and a winding channel or groove 35 running around its outer peripheral edge between spaced inner and outer rims 36, 38. As illustrated in FIG. 2C, the inner rim 36 is cut out or eliminated at region 39 in the space 28 between the two hinge portions 25, 26, so that the winding channel or groove is open on one side in this space to allow for fiber crossover and bending as the device is folded, as described in more detail below in connection with FIG. 4. The first face 32 has an annular ledge 41 which extends inwardly beyond the winding groove and has an inner peripheral edge 31 which surrounds opening 30. Two diametrically opposed keys or projections 40, 42 are provided in the inner peripheral edge of the annular ledge 41. A series of spaced openings 44 are provided around ledge 41 of each spool member.
The hinge portions or living hinges 25, 26 allow the dual spool device 20 to be folded between an open condition as illustrated in FIG. 2A in which the spool members 22,24 are in spaced, side-by-side and coplanar positions, and a closed, folded condition as illustrated in FIG. 2D, in which the inner faces 32 of each spool member face inwardly and are aligned face-to-face, as indicated in FIG. 2D, with the keys 40,42 and openings 44 in each annular ledge 41 aligned. As can be seen in FIG. 2D, the winding channels or grooves 35 are on the outside of the hinge when the device is folded.
In order to wind a length of one or more individual fibers or ribbon fibers 45 between points 46, 47 of the fiber onto device 20, as illustrated schematically in FIG. 3, the device is first positioned in the fully open condition. In practice, when optical fiber is to be managed, the points 46 and 47 are locations where the fiber or fibers extend out of respective devices to be connected together, and may be fixed or unfixed. The spliced length of fiber 45 between these points is the slack which is to be managed by the fiber management apparatus or device 20. The windings or turns of fiber are shown outside the winding grooves in FIG. 3 for clarity in understanding the winding method, but in practice these turns will be made in the grooves. A first turn of the fiber 45 is made in a first direction in the direction of arrows A1, A2, A3 about the spool member 24, with the winding direction as indicated by the arrows being anti-clockwise as viewed in FIG. 3. The fiber is then crossed over from the spool member 24 to the spool member 22 in the gap or cross over area 28 between the two hinge portions 25, 26, and enters the winding groove 35 in the other spool member 22. A second turn of the fiber is then made about the spool member 22 in the direction of arrows B1, B2, B3, which is clockwise as viewed in FIG. 3. At this point, depending on the length of fiber remaining, the fiber may cross over the first length of fiber in cross over area 28 at cross over point 50 and another turn may be made in a clockwise direction about the winding groove in spool member 24 followed by another turn around the winding groove in spool member 22. This figure eight winding pattern results in cancellation of twist in the fiber which would have resulted from one turn on the spool. If an even number of turns is made before the slack is taken up, there is substantially no twist remaining in the fiber. If an odd number of total turns is made, there is approximately one half turn of twist in the fiber. The device is folded into the closed, folded condition before the final winding so as to reduce the risk of accidental damage or fiber breakage on a fixed end during folding.
FIG. 4A illustrates the device 20 in the folded, closed condition after the final winding has been made. As illustrated, the gap 28 between the hinge portions and the elimination of the inner rim 36 of each spool along edge 39 between the hinge portions allows for the fiber cross over at point 50 and also allows the fiber to bend freely in the cross over area as the device 20 is folded.
FIG. 4B illustrates a modification of the device 20 in which the winding channels or grooves 135 are of a different shape to the winding grooves 35 of the embodiment of FIGS. 2 to 4A. As illustrated in FIG. 4A, winding grooves 35 are of generally rectangular cross section and uniform width. In FIG. 4B, the winding groove 135 is of generally hourglass or triangular cross-sectional shape from its inner end to its outer end, leaving a small, slit-like opening 136 which helps in locating individual fibers or ribbon fibers as they are fed into the groove, and also helps to hold fibers in the groove.
As illustrated in FIG. 2D, the openings 44 in the two spool members 22, 24 are aligned when the device is in the folded condition. Tie wraps, clips, or other holding devices may be engaged in each aligned pair of openings in this condition and extend over the winding grooves to hold the wound fiber in place, and also to hold the folding device closed. When fiber has been wound in a figure eight pattern and the device is folded into the closed condition, a folded figure eight is formed. This takes up only around half of the storage space of an extended or flat figure eight as in the prior art apparatus of FIG. 1.
The width and depth of the winding channels or grooves 35 is dependent on the thickness of fiber, fibers, or other elongate flexible elements to be wound on device 20. The device may be used for managing an individual fiber, multiple individual fiber circuits between optical devices to be connected, or a ribbon fiber. In alternative embodiments, device 20 may be used for managing other types of flexible elongate elements in the manner illustrated in FIGS. 2 to 4B, such as electrical wires or cables, steel wires and ropes as used in the construction and elevator industry, hoses such as hydraulic or pneumatic fluid carrying hoses, threads of wool, nylon, and the like as used in the textile industry, and others. The dimensions and material of device 20 may be suitably adjusted based on the thickness and the likely length of the flexible elongate element to be managed. In the case of optical fiber, fibers, or ribbon fibers, the winding groove of each spool member has a radius which is equal to or greater than the fiber minimum bend radius.
The fiber management apparatus may also comprise a mounting device for holding one or more of the folding dual spool devices 20 of FIGS. 2 to 4B. FIG. 5 illustrates one embodiment of a mounting device 55 for holding one or more of the folding devices 20 in the closed, folded condition with fiber wound onto the spools in a figure eight pattern as in FIGS. 3 and 4A. In FIG. 5, a folded dual spool device 20 is shown aligned with device 55 prior to mounting on the device. The mounting device in this embodiment comprises a base 56 having a projecting hub 58 for extending through the central opening 30 in the folded device 20. The mounting hub 58 comprises a four-finger collet having four flexible fingers 60 arranged to grip against the central opening in the spool, with gaps or keyways 62 between each adjacent pair of fingers. A greater or lesser number of fingers may be provided in alternative embodiments. A mounting recess 64 is provided on the outer surface of each finger 60.
As illustrated in FIG. 5, the folded spool device 20 is positioned with opening 30 aligned with hub 58 and keys 40, 42 aligned with keyways 62, and the central opening 30 is then moved over the hub. The keys 40, 42 engage in the keyways 62 between adjacent fingers of the hub 58 to restrict rotation of the spool device 20. The fingers 60 are urged inwardly as the device 20 is forced over the outer regions of the fingers, and then spring outwardly to grip against the inner edge 31 of the opening 30 when the folding device is aligned and seated on the mounting recess 64. As illustrated in FIG. 6, more than one folding device 20 may be mounted on the hub 58 where multiple ribbon fibers or bunches of fibers are to be managed. FIG. 6 illustrates a stack of three folding devices 20 mounted on the mounting device 55. A greater or lesser number of folding devices may be accommodated with suitable adjustment of the length of hub 58.
The base 56 of the mounting device 58 may have a mounting arrangement for engagement with stand-off rods 14 between two optical devices 16, 18, as illustrated in FIG. 7. In the illustrated embodiment, the base 56 has one or more through bores 65 for engagement over stand off rods 14, as seen in FIGS. 5 to 7. Other types of stand-off rod engagement mechanisms may be used in alternative embodiments, such as grooves in the rear face of base 56, or an attachment clip or the like. It can be seen by comparison of the prior art fiber management apparatus of FIG. 1 with the fiber management apparatus in FIG. 7 that the amount of space needed to manage the fibers is substantially halved with the folding figure eight storage pattern of this embodiment. In FIG. 7, each folding device may store spooled fibers of multiple individual circuits or a multiple circuit ribbon fiber.
A slimmer version of the folding device 20 may be used for managing a single or individual fiber in a single optical circuit. In this alternative, the winding channel or groove 35 in each spool is much narrower than in FIG. 4, with the width not much greater than that of a single fiber. This allows a much greater number of folding devices 20 to be mounted in a stacked arrangement on mounting device 55 or other mounting devices for this purpose. Where each fiber is spooled or managed on its own dedicated folding device, troubleshooting of a circuit can be done by removing the fiber for that circuit from the folding device holding that fiber, without unwinding fibers on other folding devices. In FIGS. 1 to 7, the first and second rims 36, 38 of the folding device are of the same outer diameter. In one embodiment of a slimmer folding device, the second rim 38 which is outermost in the folded condition may be of smaller diameter than the first rim 36, since there is only one fiber wound in the groove 35 in this embodiment, and thus the groove does not have to be as deep in order to contain the fiber windings.
FIGS. 8A, 8B, 9 and 10 illustrate another embodiment of a fiber management apparatus comprising a modified folding dual spool device 70. One or more dual spool devices 70 may also be mounted on mounting device 55 after folding, like the devices 20 of the first embodiment, as discussed in more detail below. Dual spool device 70 has a pair of flat, ring-shaped members or spool members 72, 74 connected by spaced hinge portions 75, 76. A gap or cross over area 78 is located between the hinge portions, as in the previous embodiments. In device 70, a winding channel or groove 80 is provided in a first or outer face of each spool member, rather than an outwardly facing winding channel or groove at a peripheral edge of a spool, as in the embodiments described above in connection with FIGS. 1 to 7. Each winding channel or groove 80 is spaced inwardly from the outer peripheral edge of the respective ring or spool member. The grooves 80 are provided in the face of each ring member which is outermost when the device is folded into a closed, folded condition.
FIGS. 8A and 9 illustrate the device 70 in an open condition. Each ring member has a cut-out in the gap or cross over area 78 between hinge portions 75 and 76 which extends up to the groove 80. This means that the groove terminates at each end of the cross over area 78, so that fiber can enter and exit the grooves 80 when leaving or entering the cross over area or gap 78. A pair of fiber entry/exit grooves 83 are also provided on the outer face of each ring member, each extending tangentially in opposite directions from the winding groove 80 to the outer peripheral edge 82 of the ring member.
Each ring member has a central opening 84 and an inner peripheral edge 85. A pair of diametrically opposed keys or projections 86 project inwardly towards one another from the inner peripheral edge 85. These keys have the same purpose as the keys 40, 42 in the previous embodiment, i.e. for alignment and anti-rotation purposes when the folding device 70 is folded and mounted on a hub 58 of a mounting device 55. A series of spaced openings 88 are provided around each ring member in the space between the winding groove 80 and the inner peripheral edge 85. As in the previous embodiments, the openings 88 may be used for ties, clips, or the like to hold wound fiber on the device 70, and also to hold the device in the closed, folded condition of FIG. 10.
As noted above, FIGS. 8A and 9 illustrated the folding device 70 in the flat, open condition. In this condition, a length of an individual fiber 90 or other narrow wire or line extending between points 92, 94 may be wound onto the two spools in the manner generally illustrated in FIG. 9. Starting from end 92, a first turn of the fiber may first enter the channel or groove 80 in ring member 72 through a selected entry groove 83, extend a short distance around that groove, then pass across the gap or cross over area 78 to enter the groove 80 in the second ring member 74, extending in an anti-clockwise direction for one turn in groove 80 before crossing over the first turn at a cross-over point 95 in gap 78 (see arrows A1, A2, A3 and A4). The fiber is then wound in a clockwise direction around groove 80 in ring member 72 (see arrows B1, B2), and may either exit the spool via groove 83, or may continue back onto the ring member 74 in the same path A1, A2, A3, A4, dependent on the amount of fiber to be wound onto device 70. The provision of four entry/exit grooves allows the fiber to enter and exit the device at the most convenient location, dependent on the length of fiber to be wound or spooled onto the device.
When a majority of the length of fiber has been wound onto device 70, and there is only a turn or less of fiber left to be wound, device may be folded from the open condition of FIG. 9 to the closed, folded condition of FIG. 10. FIG. 8B illustrates an intermediate, partially folded position of the device during folding. The hinge portions 75, 76 are designed to fold in the direction illustrated in FIG. 8B, with the face of each ring member 72, 74 which has no winding groove facing inwardly and the wound fiber on the outside of the folded device. The cross over area or gap 78 between the hinge members allows the fiber to bend easily. Once the device is folded into a closed, folded condition with the two ring members 72, 74 face to face, any remaining length of the fiber can be wound around the appropriate winding groove to take up substantially all the remaining slack in the fiber. The two ring members can be secured together in the folded condition by passing suitable ties, clips or the like through some or all of the aligned openings 88.
The device 70 has a slimmer profile when folded than the fiber management device of FIGS. 1 to 4, as can be seen by comparing FIG. 10 with FIG. 4. One or more of the folding devices 70 of FIGS. 8 to 10 can be engaged on the hub of mounting device 55 in a similar manner to the folding fiber management devices 20 of the first embodiment, with the aligned central openings engaging over the fingers and the keys 86 engaging in the keyways 62 between adjacent fingers. Several of the folding devices 70 may be used to spool individual fibers and then mounted in a stack on the hub 58 of a mounting device 55 after folding into the closed condition of FIG. 10, and the mounting device can then be mounted in the space between the optical devices from which the fibers extend, as described above in connection with the first embodiment.
The folding device 20 of the first embodiment above may be used for handling or spooling lengths of multiple individual fibers, ribbon fibers, or other elongate lines when the ends of the lines are not accessible. In the case of optical fibers, a length of one or more individual fibers or ribbon fiber typically projects from an exit end of an optical device to be connected in line with other optical devices, such as an optical or hybrid device housing and an optical or hybrid cable. These lengths of optical fiber are commonly known as pigtails, and the pigtail length is made sufficient to allow for splicing on fusion splicing equipment. The fiber pigtail may be an individual fiber, a bunch of individual fibers, or one or more ribbon fibers which contain multiple fibers in a ribbon-like form. The folding device 70 of FIGS. 8 to 10 is intended for use in managing a single fiber, wire or other thin flexible line, while folding device 20 may be used to manage an individual fiber, plural individual fibers, or one or more ribbon fibers. In either case, the length of pigtails to be connected together prior to winding on devices 20 or 70 may be adjusted prior to splicing so that the overall length of the spliced fiber or line is equal to substantially a whole number of turns on the device, while still providing a sufficient length for splicing purposes. This adjustment can reduce the amount of slack in the spliced fiber after winding onto the folding fiber management device.
A method of adjusting the length of fiber to be managed so that it is close to a whole number of turns on the device 20 is described below, with reference to FIG. I 1. A similar method is used to adjust the length of fiber when it is to be wound on device 70. As noted above, a fiber pigtail of one or more individual fibers or ribbon fiber normally extends from a housing or enclosure for an optical fiber device such as an optical connector shell or a cable termination housing before the device is connected to another such device in an assembly.
In FIG. 11, the length L1 is the pigtail length from the fixed point or end of one of the fibers or ribbon fibers at a first device, the length L2 is the pigtail length from the fixed point or end of the other fiber or ribbon fiber at a second device, d is the diameter of the winding channel or groove on each spool of device 20, and l1 and l2 are the distances on each side of the folding device 20 from the fibers' fixed points to the points where the spliced fiber joins the respective winding channel or groove 35, typically at the apex or uppermost region of the spool. Prior to splicing, a total spliced fiber length L is calculated as follows: L=L1+L2=l1+l2+nπd+ε, where ε<<<d is a small additional length to compensate for fiber buildup on the winding grooves with successive fiber windings, and n is an integer corresponding to a number of turns on dual spool device 20. Using this relationship, the installer can calculate total spliced fiber lengths L corresponding to substantially a whole number of turns on the two fiber winding grooves, so that only a small amount of excess fiber is left after winding in the figure eight pattern as described above. The integer n may be an even or odd number. Where n is an odd number, there is one half turn of twist left after winding on the spools. After calculating the length L, the pigtails can then be cut to appropriate lengths. The length L1 and the length L2 may be different as long as the total of these lengths meets the above relationship, and the installer can appropriately adjust these lengths based on the available pigtail lengths on each side.
In the event of fiber damage after a splice, a section of length qπd, where q is an integer, which spans the damaged portion may be removed or cut out before re-splicing. If possible, depending on the length of the damaged portion, q is equal to one so as to minimize the discarded fiber. This means that the fiber length after splicing is still approximately equal to a whole number of turns on the fiber winding grooves.
The above embodiments allow fibers, ribbon fibers, or other flexible elongate elements or lines to be managed in a figure eight pattern on dual spools with windings on each spool being in opposite directions to cancel or reduce twist. At the same time, the hinge between the spools allows the spools to be folded along a central fold or hinge line into a folded, closed condition, to take up approximately half the space of the fully extended dual spools. The winding grooves are located outside the hinge on folding, reducing the risk of fiber in the cross over area contacting a spool member during folding into the closed condition.
The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles described herein can be applied to other embodiments without departing from the spirit or scope of the invention. Thus, it is to be understood that the description and drawings presented herein represent a presently preferred embodiment of the invention and are therefore representative of the subject matter which is broadly contemplated by the present invention. It is further understood that the scope of the present invention fully encompasses other embodiments that may become obvious to those skilled in the art and that the scope of the present invention is accordingly limited by nothing other than the appended claims.
Patent Application
20080296426
