WO 2008/078058 PCT/GB2006/004906 1 Optical fibre management system Field of the Invention 5 The present invention relates to a fibre management system for managing and distributing optical fibres. Furthermore, the present invention relates to a fibre management 10 assembly to be used in a fibre management system. Background to the Invention Optical fibre assemblies for management and distribution of optical 15 fibres are known in the art. The optical fibre assemblies are used, for example, in joint closures, wall boxes, distribution cassettes, central office equipment as well as in optical fibre networks, e.g. the fibre-to-the-home (FTTH) networks. 20 Generally, an optical fibre assembly comprises a plurality of splice trays, such as 4 or 8 trays, for storing and splicing the optical fibres together. Moreover, typically an optical fibre assembly further comprises routing elements (e.g. transportation tubes or routing channels) for suitably directing the optical fibres - which enter the optical fibre assembly - to the splice trays. 25 Managing how the optical fibres are routed to the splice trays and how a user - typically an installer - gains access to the individual splice trays is an important and quite complex operation.
WO 2008/078058 PCT/GB2006/004906 2 According to a solution known in the art, a stack of splice trays is provided wherein each splice tray is mounted so that it can be swivelled out of the stack to be accessed by a user. For example, access to a splice tray is allowed to an installer so as to coil and splice the optical fibres within the 5 splice tray. Such a technical solution is disclosed, for instance, in documents EP-1,302,798 and FR-2,678,076. The Applicant has noted that the splice trays arrangement mentioned above takes up a lot of space within the enclosure or box in which the stack is 10 located. In particular, the Applicant has noted that the splice trays arrangement mentioned above takes up a lot of room horizontally within said enclosure. Moreover, the Applicant has also noted that the routing of the optical fibres to the splice trays of said arrangement is generally quite difficult. Generally, the complexity of this arrangement is further increased 15 by the need of providing a transport tube which represents an extra element to be provided and, moreover, to be fitted by the installer. According to a further solution known in the art, a stack of splice trays is provided wherein each splice tray is stacked at a given angle so that it can 20 be accessed by flipping up the splice trays above it. Such a technical solution is disclosed, for instance, in document WO 2004/021061. The Applicant has noted that the splice trays arrangement mentioned above takes up a lot of space within the enclosure or box in which the splice 25 trays are stacked. In particular, the Applicant has noted that the splice trays arrangement mentioned above takes up a lot of room vertically within said enclosure since the splice trays need to be vertically spaced from each other in order to allow flipping thereof. 30 A further solution known in the art is disclosed by document US 4,948,220. This document relates to a module for distributing and connecting WO 2008/078058 PCT/GB2006/004906 3 optical fibres, said module including a plurality of optical fibre loop supports and a plurality of optical fibre connector supports that are arranged vertically and parallel to an opening front face of said module. The supports can be translated together out of the module in a direction perpendicular to the front 5 face of the module, and then rotated together about an axis parallel to the front face of the module. The supports are then vertical and parallel to each other, and perpendicular to the front face of the module. Each of the supports can then be pivoted individually about an axis perpendicular to the support, to be clear of the other supports. Optical fibres are stored underneath the supports 10 in storage compartments. A further solution known in the art is disclosed by document US 7,035,520. This document relates to a splicing cassette (tray) management system which includes a plurality of splicing cassettes arranged in a splicing 15 cassette holder. Each of the splicing cassettes is rotatably mounted along an edge at a given angle so that each cassette can be rotated about said edge. Moreover, the splicing cassette holder is rotatably mounted on a pull-out mounting device. The mounting device and the splicing cassette holder can be translated in a first plane and then the splicing cassette holder can be 20 rotated along an edge from the first plane into a second plane, said second plane being perpendicular to the first plane. The Applicant has noted that the solutions disclosed by documents US 4,948,220 and US-7,035,520 require a relatively complex set of movements 25 as well as quite considerable space in order to operatively access the splice trays. In particular, the Applicant has noted that the complex set of movements mentioned above can cause the optical fibres to be overstressed, thereby negatively influencing signal transmission of the optical cable. 30 The Applicant has perceived the need of providing an optical fibre management assembly in which the space is efficiently distributed so as to WO 2008/078058 PCT/GB2006/004906 4 suitably accessed to the optical fibres meanwhile ensuring both easy installation of the assembly and suitable protection of the optical fibres, for instance by limiting movement of and stresses on the optical fibres, so that minimum bend radius thereof can be maintained. 5 Summary of the Invention The Applicant has found that the overall dimensions of an optical fibre management assembly can be advantageously reduced - while ensuring that 10 an operator can easily access to the splice trays and the optical fibres are correctly and safely routed through the assembly - by allowing the assembly to be rotated about a first vertical axis and by allowing each splice tray to be rotated about a second horizontal axis which is substantially perpendicular to the first vertical axis. 15 The Applicant has found that by providing an optical fibre management assembly with a double hinge mechanism, according to which the whole assembly is rotated about a first axis and the splice trays can be rotated about a second axis that is substantially perpendicular to the first axis, functionality 20 and easiness of installation are advantageously maximized in managing and routing the optical fibres inside the assembly with respect to the optical fibre management assemblies known in the art. According to a first aspect, the present invention relates to an optical 25 fibre management assembly which comprises: * a supporting element; e at least one splice tray mounted on the supporting element, and " at least one distributing element for routing the optical fibres through the assembly, WO 2008/078058 PCT/GB2006/004906 5 wherein the assembly is pivotable about a first axis of said distributing element and the at least one splice tray is pivotable about a second axis which is substantially perpendicular to said first axis. 5 As a result of the present invention, an optical fibre management assembly is provided which is easy to install and easy to access. Splice trays can be stored with efficient use of space, at the same time as providing ease of access to the splice trays, for example, for splicing optical fibres, and optimising the storage of the optical fibres, for example, by limiting the 10 amount of movement of and stresses on the optical fibres and maintaining minimum bend radius of the optical fibres. The optical fibre management assembly of the present invention is of the modular type, i.e. more than one assembly can be vertically stacked for a 15 better and more efficient use of space. Modularity is peculiar of the present invention and it represents a particularly advantageous aspect of the present invention since the number of stacked assemblies can be chosen by the installer on the basis of the effective needs of the customer's network. 20 Thanks to the modularity of the assembly of the present invention, a plurality of assemblies can be superimposed in order to obtain a vertical stack thereof. It is particularly advantageous that each stacked assembly can be individually rotated about a vertical axis which is common to all the assemblies so that only the specific assembly of the stack - and thus only the 25 specific splice trays of the rotated assembly - on which the installer is requested to operate has to be rotated. Such a result is obtained thanks to the fact that the optical fibre management system of the present invention keeps the rotary pivot mounted in the housing where the stacked assemblies are positioned. In fact, by combining the distributing element with the pivot axis 30 about which the assembly can rotate (i.e. by allowing the optical fibres which exit the assembly - to move along the axis of the distributing element), WO 2008/078058 PCT/GB2006/004906 6 the assembly of the present invention provides for the rotary movement of the assembly without moving the optical fibres, thereby preventing overstresses to occur on the optical fibres. 5 According to a further aspect, the invention relates to an optical fibre management system which comprises at least two optical fibre management assemblies, each assembly comprising e a supporting element; * at least one splice tray mounted on the supporting element, and 10 e at least one distributing element for routing the optical fibres through the assembly, wherein: e the at least two optical fibre management assemblies are superimposed to each other; 15 e each assembly is pivotable about a common first axis possessed by the distributing element of each assembly, and e the at least one splice tray of each assembly is pivotable about a second axis which is substantially perpendicular to said first axis. 20 As mentioned above, the optical fibres can be managed efficiently within each assembly, and each assembly can be individually rotated without moving the optical fibres. In case a plurality of assemblies are stacked on top of one another, the optical fibres can be routed to any of the assemblies along 25 the pivot axis of the assembly distributing element. As a result, optical fibres can be routed to respective splice trays with efficient use of space whilst minimising movement and bending stresses of the optical fibres in use. 30 WO 2008/078058 PCT/GB2006/004906 7 This result can be obtained by providing the distributing element with a central bore by means of which the optical fibres can be guided through the assembly. 5 The supporting element of the assembly comprises a plurality of routing channels for guiding the optical fibres to respective splice trays. The routing channels are distributed along the supporting element. In particular, the routing channels are distributed along a first distributing element and a second distributing element, said first and second distributing elements being 10 arranged at the opposite axial edges of the stacked splice trays. Managing and distribution of the optical fibres through the assembly, in particular around the second distributing element and on the rear portion of assembly, advantageously prevents movements of the optical fibres. 15 Preferably, the routing channels are substantially parallel to each other and are arranged in planes that are substantially perpendicular to the plane along which the supporting element extends. Preferably, the routing channels are co-planar with the respective splice trays, each routing channel corresponding to a specific splice tray. 20 During operation of the optical fibre management system, the stacked splice trays are stored in horizontal planes so as to save space vertically within the housing in which the assemblies are positioned. Typically, each splice tray is pivotable of an angle which has a maximum value of about 90'. Such 25 a rotation - which is carried out by the installer in order to access to lower splice trays - is substantially reduced with respect to some technical solutions know in the art according to which the splice trays are able to flap around. This reduced movement of the splice trays of the assembly of the present invention is particularly advantageous for the reason that it prevents 30 overstressing of the optical fibres WO 2008/078058 PCT/GB2006/004906 8 Storing the stacked splice trays in horizontal planes allows that a predetermined gap - which is extended in the vertical direction, i.e. in the direction of the stacked splice trays - is provided between adjacent splice trays for ease of identity of each individual splice tray. Furthermore, storing 5 the stacked splice trays in horizontal planes allows each assembly of the optical fibre management system to be rotated out of the stack without needing to move the splice trays which are maintained in their horizontal arrangement (i.e. the splice trays are kept in the same orientation when the assembly is rotated), thereby avoiding occurrence of overstressing on the 10 optical fibres. Finally, storing the stacked splice trays in horizontal planes allows the packing density of the assembly to be advantageously maximized. In the specification, references to an item rotating about a point mean that the item rotates about an axis perpendicular to the plane of the item, that 15 is, the item swivels, and references to an item rotating about a line mean that the item rotates about an axis in essentially the same plane as the item, or a parallel plane, that is, the item flips or is hinged. References to pivoting cover both rotating about a point and rotating about a line. 20 Brief Description of the Drawings An embodiment of the invention will be described with reference to the accompanying drawings, of which: 25 Fig. 1 is a perspective view of an optical fibre management assembly according to an embodiment of the invention; Fig. 2 is a rear perspective view of the assembly of Fig. 1; Fig. 3 is an exploded perspective view of the assembly of Figs. 1 and 2; Fig. 4 shows the optical fibre tracking through the assembly of Fig. 1; 30 Fig. 5 shows the assembly with a splice tray in a lifted position; Figs. 6 shows two stacked assemblies that are mounted in a box.
WO 2008/078058 PCT/GB2006/004906 9 Detailed Description of the Preferred Embodiments As shown in Figs. 1 and 2, the optical fibre management assembly 100 5 according to an embodiment of the present invention includes a supporting element 2 and a plurality of splice trays 4 (nine splice trays in the figures), said splice trays being mounted on the supporting element. According to the present invention, the splice trays 4 are superimposed in a stack and lie flat in respective parallel planes. In detail, when the assembly is installed and the 10 splice trays are not accessed by the installer for operating thereon, each splice tray 4 usually lies in a horizontal plane while the stack of the splice trays 4 extends vertically. This means that, when the assembly is installed and the splice trays are not accessed by the installer for operating thereon, each stacked splice tray 4 lies in a plane which is substantially perpendicular to the 15 vertical plane along which the supporting element 2 usually extends. Each splice tray 4 is mounted on and coupled to the supporting element 2 by means of a respective hinge 24 (as better shown in Fig. 3). Thanks to hinges 24 each splice tray can pivot about a respective horizontal axis which 20 is obtained by intersecting the plane on which lies the splice tray and the vertical plane along which the supporting element 2 extends. The supporting element 2 includes a first distributing element 6 and a second distributing element 8 which provide for the correct distribution of the 25 optical fibre entering to and exiting from the splice trays 4. In detail, the first distributing element 6 (in the form of a first mandrel) is positioned at one end of the supporting element 2 (specifically at the left-hand side of assembly 100 as seen from the front) and the second distributing element 8 (in the form of a second mandrel) is positioned at the other end of the supporting element 2 30 (specifically at the right-hand side of assembly 100 as seen from the front). The first distributing element 6 has a central bore 10 for mounting the WO 2008/078058 PCT/GB2006/004906 10 supporting element 2 on a shaft (not shown) so as to allow rotation of the assembly 100 with respect to the housing 44 (schematically represented in Fig. 6) in which the assembly 100 is enclosed. As shown in the figures, the splice trays 4 are mounted onto the supporting element 2 between the first 5 distributing element 6 and the second distributing element 8. In a preferred embodiment of the present invention, the outer diameter of the first and second distributing elements 6, 8 is about 60 mm. As better shown in Fig. 2, a tray 12 is mounted on the rear of the 10 supporting element 2 to accommodate at least one optical splitter. As better described in the following of the present description, the optical splitter is used for splitting an optical fibre entering the assembly 100 in at least two optical fibres to be conveyed to at least one splice tray 4. As better shown in Fig. 3, the tray 12 is provided with a cover 14. 15 Fig. 3 is an exploded perspective view of the assembly 100 according to the embodiment shown in Fig. 1. As illustrated in Fig. 3, the supporting element 2 comprises: a front portion 16, a rear portion 18, a covering element 20, and a shaft element 22. 20 The front portion 16 comprises the hinges 24 which, as mentioned above, allow the splice trays 4 to be mounted on the supporting element 2. Moreover, the front portion 16 comprises a semi-cylindrical portion 26 which is located at one axial end of the front portion 16. In detail, the semi 25 cylindrical portion 26 is positioned at the right-hand side of the assembly 100 and contributes in forming the second distributing element 8. The rear portion 18 comprises a semi-cylindrical fixing portion 28 and a semi-cylindrical portion 32. 30 WO 2008/078058 PCT/GB2006/004906 11 In detail, the semi-cylindrical fixing portion 28 forms part of the first distributing element 6 and contributes in mounting the supporting element 2 on the shaft (not shown in the figures) at one end of the assembly 100 (specifically, at the left-hand side of assembly 100 as shown in Fig. 1). The 5 semi-cylindrical fixing portion 28 includes a C-shaped portion 30 which contributes in obtaining the central bore 10 which, has mentioned above, is used for coupling the supporting element 2 to the housing 44 and allowing rotation of supporting element 2. 10 The semi-cylindrical portion 32 forms part of the second distributing element 8 at the other end of the assembly 100 (specifically, at the right-hand side of assembly 100 as shown in Fig. 1). In detail, the semi-cylindrical portion 26 of the front portion 16 and the semi-cylindrical portion 32 of the rear portion 18 together enclose the shaft element 22 and form the second 15 distributing element 8. The covering element 20 combines with the semi-cylindrical fixing portion 28 of the rear portion 18 to fonn the first distributing element 6 as well as the central bore 10 provided thereto. 20 As shown in Fig. 3, the inner surfaces of the semi-cylindrical portions 26 and 32 of the front and rear portions 16, 18 respectively are provided with a plurality of routing channels 34 for guiding and storing the optical fibres. In detail, said inner surfaces, i.e. the lateral surfaces which face the shaft element 25 22, are provided with grooves which are substantially parallel to each other and follow the curvilinear profile of the supporting element 2 along the longitudinal extension thereof. Preferably, the routing channels 34 are evenly distributed along the inner surface of the semi-cylindrical portion 26 of the front portion 16 and along the inner surface of the semi-cylindrical portion 32 30 of the rear portion 18. Corresponding routing channels of the semi-cylindrical portions 26 and 32 of the second distributing element 8 combine to form a WO 2008/078058 PCT/GB2006/004906 12 plurality of substantially parallel circular routing channels 34 for guiding the optical fibres around the shaft element 22 and directing the same to respective splice trays 4. 5 According to the present embodiment, also the inner surface of the covering element 20 includes a plurality of substantially parallel routing channels 34 for guiding and storing the optical fibres also along the first distributing element 6. 10 As better shown in Fig. 4, each splice tray 4 comprises a central storage track 38 for routing and storing the optical fibres and splice bays 40 for storing splice joints, i.e. for storing the splicing area between two optical fibres. In this embodiment, each splice tray can store up to 12 optical fibre splices. 15 Fig. 4 schematically shows an example of an optical fibre which is routed in the optical fibre management assembly 100 according to the present invention. In the figure, the optical fibres that are represented by solid lines are visible in the view as shown, while the optical fibres that are represented 20 by dashed lines are contained within the assembly 100 or obscured by constitutive components of the assembly 100. An optical fibre 36 (input optical fibre) is input to the rear of the assembly 100. The optical fibre 36 is carried by an optical cable 46 (shown in 25 Fig. 6) which enters the housing 44 in which the assembly 100 is positioned. The optical fibre 36 is routed through the tray 12 which is located on the rear of the assembly 100, said tray 12 being provided with at least one splitter. In the splitter the optical fibre 36 is split into a plurality of optical fibres, only one optical fibre (which is indicated with reference sign 50) being shown in 30 Fig. 4. Point K in Fig. 4 indicates the point in which the input optical fibre 36 is split and originates the split optical fibre 50. The split optical fibre 50 WO 2008/078058 PCT/GB2006/004906 13 enters the supporting element 2 and is routed - through a routing channel 34 to the second distributing element 8. In detail, the routing channel 34 guides the split optical fibre 50 around the shaft element 22 and then enters a splice tray 4 at a level which corresponds to the level of the routing channel 34. In 5 Fig. 4 the split optical fibre 50 is shown to enter the top splice tray of the assembly 100. The split optical fibre 50 enters the splice tray 4 in correspondence of the hinge 24, where the given splice tray is coupled to the supporting element 2. The split optical fibre 50 is wound around the storage track 38 of the splice tray 4 and then conveyed to a splice bay 40 present in 10 the splice tray. In the splice bay 40 the split optical fibre 50 is spliced to another optical fibre 42 (output optical fibre) by way of a splice joint (not shown). The output optical fibre 42 - which enters the assembly 100 - comes from an optical cable which is connected to a customer's premises. The output optical fibre 42 is wound around the storage track 38 of the splice tray 15 4 and exits the rear of the splice tray 4 passing into the supporting element 2 in a direction towards the first distributing element 6. In detail, the output optical fibre 42 passes out through the central bore 10 of the first distributing 6, which thereby also acts as a routing channel. 20 As clearly indicated above, Fig. 4 shows a partial and schematic routing of an optical fibre within the assembly 100 of the present invention. It can be appreciated that a splitter - which is an optical device for splitting optical fibres - can divide (i.e. split) an input optical fibre 36 into a plurality of split optical fibres 50. Typically, an input optical fibre 36 is split into 2, 4, 8, 16 or 25 32 split optical fibres 50, i.e. up to 32 customers can be supplied from only one input optical fibre 36. For clarity reasons, at point K of Fig. 4 only one split optical fibre 50 has been shown. Each split optical fibre 50 is routed through the supporting element 2 and the second distributing element 8 by respective routing channels 34 that enter corresponding splice trays 4. 30 WO 2008/078058 PCT/GB2006/004906 14 Moreover, as indicated above, each splice tray 4 can receive more than one splice or only a single splice is provided on each splice tray, the way of operation usually depending on the customer's fibre network. For example, a 1x32 splitter may be split to one split optical fibre 50 on each splice tray for 5 32 splice trays in the assembly 100. Some customers prefer this solution (i.e. only one split optical fibre 50 is present on each tray) so that each customer has a dedicated splice tray and the installer when working on the splice tray of a given customer does not disturb the optical fibres of other customers. 10 Alternatively, the 1x32 splitter may be split to two split optical fibres 50 on each splice tray for 16 splice trays in the assembly 100. Alternatively, a 1x32 splitter may be split to four split optical fibre 50 on each splice tray for 16 splice trays in the assembly 100. Said solutions are less expensive since more than one customer (e.g. 4 or 8 customers) are present on the same splice 15 tray. According to the present invention, more than one assembly 100 can be employed within the same housing 44. In fact due to the advantageous modularity of the assembly 100 of the present invention, two or more 20 assemblies 100 can be stacked by superimposing one assembly to the other(s). Therefore, the optical cable 46 which enters the housing 44 can contain more than one input optical fibre 36, each input optical fibre 36 being suitably conveyed to a given assembly 100. The input optical fibres 36 can be routed to the superimposed assemblies at the rear of the assembly 100. Preferably, 25 the input optical fibres 36 are routed to the superimposed assemblies through the central bore 10 which is present in the first distributing element 6 provided by each assembly 100. All the constitutive components as well as the dimensions of the 30 assembly are designed to maintain minimum bend radius of the optical fibres.
WO 2008/078058 PCT/GB2006/004906 15 As shown in Fig. 5, the splice trays 4 (in the figure the top splice tray being specifically shown) can be flipped up to expose the underneath splice trays. This means that the top splice tray 4 can be rotated out of the horizontal plane, said horizontal plane being the plane which contains the splice tray 4 5 when the assembly 100 is in a typical working operation inside the housing 44 shown in Fig. 6. On the contrary, in the case an installer needs to work in the splice tray 4' underneath the top splice tray 4, according to the assembly 100 of the present invention the hinge 24 allows the top splice tray 4 (as well as all the splice trays mounted on the supporting element 2) to be rotated about the 10 horizontal axis X (shown in Fig. 5), the axis X being obtained by intersecting the plane on which lies the splice tray and the vertical plane along which the supporting element 2 extends. Similarly, all the other splice trays 4 in the stack can be flipped up so 15 that any of the splice trays can be accessed when they are in a horizontal configuration. This aspect is particularly advantageous since the user - e.g. an installer who is requested to route and splice a further optical fibre within the assembly 100 - can easily access the desired splice tray by flipping up the splice trays which are positioned above said desired splice tray. 20 At the end of the operation which has been carried out by the installer on the desired splice tray, the splice tray or trays 4 can be flipped down again so that all the splice trays advantageously lie in parallel horizontal planes, such a horizontal configuration allowing to save space inside the housing 44. 25 Fig. 6 shows two superimposed assemblies 100, 100' - each assembly being of the form shown in Figs. 1 to 5 - which are mounted in a housing 44. It can be noted that the central bore 10 of each of the first distributing elements 6 is mounted on a vertically extending shaft (not shown) so that each 30 assembly can be rotated about said shaft in order to allow an installer to operate on a single assembly. For instance, in Fig. 6 the assembly 100' is WO 2008/078058 PCT/GB2006/004906 16 shown to be rotated while the assembly 100 is fixed to the housing vertical wall 200. As shown in Fig. 6, one assembly 100' is mounted vertically above the 5 other 100 forming a vertical stack of 18 splice trays. The housing 44 also includes an optical fibre guide 48 where routing channels 60 are provided for guiding the optical fibres to the assemblies 100, 100'. As mentioned above, preferably the optical fibres of the optical cable 46 10 are routed to the assemblies 100, 100' through the central bores 10 of the first distributing element 6. The optical fibres which are introduced into the central bores 10 are substantially undisturbed when any of the assemblies is rotated about the shaft (not shown) which is positioned along the vertical axis Y. 15 In a storage position, when not being accessed by an installer, the rear of the assemblies 100, 100' is adjacent to the rear (vertical) wall 200 of the housing 44. 20 To access one of the assemblies, and in particular one or more of the splice trays 4 of a given assembly, the assembly (assembly 100' in Fig. 6) is rotated about the shaft mentioned above in a clockwise direction by pulling on the second distributing element 8. In such a way all the splice trays 4 of the assembly 100' are rotated together while still maintained in their horizontal 25 planes. Successively, a splice tray 4 of interest can then be accessed by the installer by simply flipping up the splice trays above the desired splice tray, as shown in Fig. 5. The optical splitter which is housed in the rear tray 12 is installed at the 30 factory, and generally is not accessed by the installer. However, if necessary, the splitter can be easily accessed by rotating the assembly 100' and by WO 2008/078058 PCT/GB2006/004906 17 removing the cover 14 which protects the splitter. More than one splitter can be eventually present in each rear tray 12. In the embodiment shown in the figures, each assembly 100 has only 9 5 splice trays. However, different numbers of splice trays can be used, such as 4, 8 or 12. Moreover, multiple assemblies 100 can be stacked to achieve the number of splice trays required by the customer.