A cable assembly, method of using a cable assembly and method of manufacturing a cable assembly

Abstract

A cable assembly (100, 500, 600, 700, 700', 900) includes a series of preterminated optical fibre cable units (102, 102') arranged within a supporting structure (120). Each cable unit has connectors (114, 116) fitted at its ends. The supporting structure includes a shell partially enclosing a first cavity (526, 626, 726) that extends within the structural component and houses a first subset of the cable units. Successive cable units are arranged overlapping one another such that the second end of a first cable unit in the series overlaps the first end of a second cable unit. In use, the cable assembly is installed along a desired route to form part of a network. The second connector (116) of the first cable unit (102) and the first connector (114') of the second cable unit (102') are broken out of the cable assembly and both connected to a drop terminal (200).

Description

[0001] A CABLE ASSEMBLY, METHOD OF USING A CABLE ASSEMBLY AND METHOD OF MANUFACTURING A CABLE ASSEMBLY

[0002] FIELD OF THE INVENTION

[0003] The present disclosure relates generally to cable assemblies and methods for use in the deployment of networks for communications and / or power supply. The invention may be used for example in the deployment of optical fibre broadband networks within neighbourhoods and large premises.

[0004] BACKGROUND TO THE INVENTION

[0005] Considering, for example, the deployment of optical fibre broadband connections to homes and business premises, it is known that fibre optic cables can be installed by a variety of methods, whether through the ground, via ducts, and via service spaces within buildings. Known methods include direct burying (trenching), pulling through ducts, pushing through ducts, blowing through ducts, aerial spans and combinations of these. Fibre-to-the- Premises (FTTP) is a generic term for broadband network architecture that uses optical fibre technology to carry data to a premises (whether residential or otherwise) from a broadband service provider via a telecommunications cabinet located near a customer premises. This is sometimes referred to as "last mile" connectivity.

[0006] In one type of deployment, individual premises are connected to a network via so-called drop terminals, that are positioned along a route and connected to a distribution point via one or more cables. Each drop terminal may supply one, two or many premises. By multiplexing several signals on a single optical fibre or pear optical fibres, several premises can be connected to the network using a splitter at the drop terminal. User terminals may also be connected wirelessly to a communications network, for example using Wi-Fi and / or 5G access points. These access points are connected to a distribution point of the network the optical fibre cables, and optionally power cables also.

[0007] In order to improve the quality and reduce the cost of building such networks, the use of preterminated cables is increasingly popular, as the complicated termination, splicing and other steps can be performed in a clean factory environment, rather than in the street. However, each deployment project is unique and to provide prefabricated cabling for each deployment remains complicated and expensive. SUMMARY OF THE INVENTION

[0008] In a first aspect of the present invention, there is provided a cable assembly comprising a series of preterminated cable units arranged within a supporting structure, each cable unit comprising a length of cable having a first connector fitted at a first end and a second connector fitted at a second end, wherein the supporting structure includes a structural component that forms a shell of the cable assembly, the shell at least partially enclosing a first cavity that extends within the structural component, wherein the first cavity houses at least a first subset of the series of preterminated cable units, and wherein the successive cable units extend over different successive portions of an overall length of the cable assembly, said portions of the overall length overlapping one another such that the second end of a first cable unit in the series overlaps the first end of a second cable unit.

[0009] In some examples, the first cavity is formed with a longitudinally-extending opening such that the preterminated cable units can be inserted and / or removed without cutting the structural component.

[0010] A second aspect of the present invention provides a method of using a cable assembly according to the first aspect of the invention above, the cable assembly having been installed along a desired route to form part of a distribution network for communication signals and / or electrical power, wherein the second connector of the first cable unit and the first connector of the second cable unit are broken out of the cable assembly and both connected to a first drop terminal of a distribution network.

[0011] The first drop terminal may be configured to relay an optical signal received via the first cable unit into the second cable unit. The signal may be relayed to successive drop terminals in this way, and may be distributed from each drop terminal to one or more user terminals or other equipment.

[0012] A third aspect of the present invention provides a method of manufacturing a cable assembly, the method comprising the steps:

[0013] (a) manufacturing a series of preterminated cable units, each cable unit comprising a length of cable having a first connector fitted at a first end and a second connector fitted at a second end; and (b) arranging the series of preterminated cable units within a supporting structure in such a way that successive cable units extend over different successive portions of an overall length of the cable assembly, said portions of the overall length overlapping one another such that the second end of a first cable unit in the series overlaps the first end of a second cable unit.

[0014] These and other features and advantages of the present disclosure will become apparent from a consideration of the claims and the following description and drawings.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments of the present disclosure will now be described by way of example only, with reference to the accompanying drawings, in which:

[0017] Figure 1 shows schematically a representative preterminated cable unit and a cable assembly incorporating a series of preterminated cable units arranged within a supporting structure;

[0018] Figure 2 illustrates the connection of two of the cable units of the cable assembly, at a terminal forming a local distribution point of a communications network;

[0019] Figures 3 and 4 illustrate schematically the cross-section of example cable assemblies of the type illustrated in Figure 1 and Figure 2, these examples being formed without a structural component that forms a shell of the supporting structure;

[0020] Figures 5 to 9 illustrate schematically the cross-section of various example cable assemblies of the type illustrated in Figure 1 and Figure 2, these examples including a structural component that forms a shell of the supporting structure in accordance with the first aspect of the present invention;

[0021] Figure 10 illustrates schematically how a cable assembly may be used to deliver signals to successive local distribution points in a first example method according to the present invention; and

[0022] Figure 11 illustrates schematically how a cable assembly may be used to deliver signals to successive local distribution points in a second example method according to the present invention. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0023] Figure 1 illustrates schematically the form of a cable assembly 100 comprising a series of preterminated cable units 102, 102' etc. arranged within a supporting structure 120. A representative cable unit 102 is shown in enlarged detail at the top of the drawing. The cable unit comprises a length of cable, for example but not limited to an optical fibre cable. The preterminated cable units 102, 102' etc. are manufactured in advance such that each cable unit has a first connector 114 fitted at a first end and a second connector 116 fitted at a second end. Such preterminated cable units may be referred to in the art as "jumper cables". Once these jumper cables have been made to the required length and other specifications, they are assembled to form the cable assembly. Within the overall length Lo of the cable assembly, successive cable units extend over different portions or sub-lengths labelled LI, L2, ...Ln in the drawing.

[0024] In the following description, fibre optic cables are used as examples of cable units that may be included in the cable assembly, each cable unit containing one or more optical fibres. As the main type of cable throughout the description, the structures and techniques disclosed herein are equally applicable for use with electrical (e.g. copper] cables and also for so- called 'hybrid' cables that carry both electrical and optical signals. The term cable is understood to encompass any type of cable, unless the context requires otherwise. Of course, the types of connectors used and the types of cable used will the selected according to the particular types of signals that are to be carried through the connector.

[0025] For some use cases, it may be convenient that the lengths Ll-Ln of the portions are all identical. However, for a practical use case such as the one discussed below, the lengths of the cable units may all be individually customised in accordance with a planned route for installation of the cable, and the locations of certain terminals along that route. For the purposes of the present description, it may be assumed that all of the connectors 114, 116 are identical, but in principle they can be customised in different ways, to suit the application. The connectors may be of a "hardened" type, for use in an outdoor environment or they may be more conventional connectors. For optical connections, hardened connectors commercially available in the market include the long-established OptiTap® connectors and the more compact Pushlok™ type, available from Corning Optical Communications LLC, Charlotte, NC 28216, USA. Accessories are also available for converting between types of connectors, for example between the Pushlok type and the standard SC connectors. Another family of hardened connectors is the Prodigy® series from CommScope LLC in the USA (www.commscope.com / prodigy). Whichever type of connector is used, for the purposes of the present disclosure it is assumed that the connectors are factory-fitted to pre-cut lengths of cable, prior to their inclusion in the overall cable assembly 100. In this way, operations to terminate optical fibres and / or electrical conductors in the individual cable units each are not required in the field, at the time of installation. Likewise, operations to terminate optical fibres and / or electrical conductors can be performed on the cable units individually, which is more convenient than performing operations to access and terminate cable units when they are already part of a larger cable assembly.

[0026] On the other hand, fitting of hardened connectors in the field is also possible and by no means excluded from the scope of the present disclosure. A cable unit that has only a cut end or a partial connector at one or both ends may be used instead of a cable unit preterminated with hardened connectors at both ends. Such a cable unit may be preferred for a given application, because it is more compact, for example. Accordingly, in the examples illustrated and described herein, it is an option to omit the hardened connector from one or both ends of one or more of the cable units.

[0027] Referring also to the enlarged schematic cutaway section of the cable assembly seen in the lower part of Figure 1, it can be seen that the portions of the overall length covered by neighbouring cable units 102, 102' overlap one another, such that the second end of a first cable unit 102 in the series overlaps the first end of a second cable unit 102'. The length of the overlap is labelled Lv. The value of Lv may be the same for each overlapping pair of cable units along the cable assembly, or it may be customised according to details of the installation route. The purpose of this overlapping arrangement will be understood better from a consideration of Figure 2, discussed below, and the application examples of Figures 8 and 9.

[0028] Concerningthe supporting structure 120 ofthe cable assembly 100, this is illustrated highly schematically in Figure 1, for the reason that it can be realised in a wide variety of ways. Some examples of possible supporting structures are illustrated and described below with reference to Figures 3 to 9. Whatever the construction, the aim is that the cable assembly can be manufactured, transported and installed along a desired route, while maintaining the arrangement of a series of preterminated cable units 102 within. After the assembly has been deployed along the route, the individual cable units can be broken out to serve their function as part of a distribution network for communication and / or power signals.

[0029] Still referring to Figure 1, in addition to the preterminated cable units 102, the cable assembly in some examples further includes at least one functional cable element 130 within the same supporting structure, separate from the series of preterminated cable units. As shown, the functional cable element 130 may extend in parallel with two or more of the series of preterminated cable units, optionally along the entire overall length of the cable assembly. More than one functional cable element may be provided in the same cable assembly. Many types of functional cable elements can be envisaged, and examples are described further below, with reference to Figures 6, 7, 8 and 9. Functional cable elements may include optical conductors and / or electrical conductors. Functional cable elements may also include microducts. Such microducts may be left empty, to be used for installing optical and / or electrical conductors at a later date. In some examples, functional cable elements include at least one pre-populated microduct and at least one empty microduct. For the avoidance of doubt, the terms "functional cable element" and "structural cable element" are used herein in the broadest possible sense. Structural cable elements of course have a function, but this function is related to the mechanical integrity of the cable assembly. Functional cable elements, as that term is used herein, are concerned with the function of the cable in carrying communications and / or power signals from place to place. The present disclosure is not concerned with cable assemblies that have a purely mechanical function. It will be further understood that the functions of functional cable element and structural cable element can be combined in various ways in a single component. For example, a composite cable may include optical and / or electrical conductors, while also providing a stiffness and / or tensile strength to the overall cable assembly.

[0030] Figure 2 illustrates how the cable assembly of Figure 1 may be used to interconnect terminals in a distribution network, for example an optical fibre broadband distribution network. It will be understood that the cable assembly may be many metres long, perhaps hundreds or even more than a thousand metres. Each cable unit may be several metres long or several tens of metres long, depending on the application. In Figure 2 we see the cable assembly 100 at a specific location, where it passes a 'drop terminal' 200. Many kinds of terminal may be envisaged, but in this example, the drop terminal is stationed along at a point along the route where signals from the cable assembly are to be distributed to one or more user terminals. User terminals in this example may, for example, be homes or business premises, or to be served with optical fibre broadband. Easy instead of user terminals, they drop terminal may be for a broadband access point, such as a Wi-Fi or 5G antenna installation. For such applications, not only optical signals but also power may be delivered through the cable assembly.

[0031] Features of the cable assembly 100 in Figure 2 are the same as shown in the bottom part of Figure 1, for the sake of example. The drop terminal 200 comprises a housing 202, within which functional components are arranged and protected from the environment. Drop terminal 200 may be located, for example below ground, in a street cabinet, or at an elevated position on the side of a building, or a utility pole. Drop terminal 200 in this example is for serving a number of user premises, such as houses, and the main functional component within is an optical splitter 204. Passive optical splitter is of this type are commonly used to distribute fibre-optic signals to groups of premises within a neighbourhood. The number of premises may be eight, 16, 24 or 32, for example while an eight-way splitter is illustrated schematically, purely by way of example. As will be illustrated further below, a neighbourhood with a distribution network may include a number of these drop terminals, each supplying a subset of the neighbourhood premises. Hundreds of premises may be supplied through the same cable assembly.

[0032] As can be seen in Figure 2, drop terminal 200 is installed near a portion of the cable assembly 100 where a second end of a first preterminated cable unit 102 overlaps cable unit 102'. As part of the network deployment method, in other words, the cable assembly is installed along a route so that this overlap portion passes by the location where drop terminal 200 is already installed, or will be installed. The overlapping ends of the cable units are broken out of the supporting structure, such that the second connector 116 of the first cable unit 102 is connected to a first port 206 of the drop terminal and the first connector 114' of the second cable unit 102’ is connected to a second port 208 of the drop terminal. Conveniently, the distance between the drop terminal and the route of the cable assembly in this type of installation should be at maximum one half of the overlap length Lv. Otherwise extension cables would be needed with associated cost and connector losses. This distance maybe less than a metre, or more than 10 m, depending on the situation. The arrangement of cable units and their lengths and overlap lengths can all be customised to the requirements of a particular route and the locations of the drop terminals along that route.

[0033] These ports 206, 208 might conveniently be referred to as an "input port" and "output port" respectively. However, such terminology should be used with care. For example, it will also be understood that a typical broadband network transmits signals in both directions, from a network access point to a user terminal, and back from the user terminal to the network access point. Moreover, in the example illustrated, a signal from the first carried by the first cable unit 102 may simply be relayed or passed through into the second cable unit 102’, which is another reason that terms such as 'input' and 'output' might be less useful.

[0034] In the example drop terminal 200, a short loop of fibre 210 is shown schematically providing this relay of optical signals from the first port 206 to the second port 208. Additionally, however, a portion of the relayed optical signal is branched off into a second fibre 212 and delivered to an input port of the optical splitter 204. Within the splitter 204, the optical signal is further divided and distributed between a number of individual drop ports 214. Each of these ports may be connected to a premises, via local drop cables. Commercial splitters provide for example between two and 32 drop ports. Again, terms such as "input" and "output" should be understood as encompassing bidirectional or duplex communication.

[0035] The skilled reader will understand that duplex communication may be provided in a single fibre (or electrical cable). Alternatively, duplex optical fibres may run in parallel, one for the signals carrying out to the user premises, and another one for the signals travelling back from the user premises. For the purposes of the present description, such measures are considered merely routine details of implementation, and need not be described in detail.

[0036] The skilled person will also understand that drop terminals may use passive optical splitters, such that no electrical power is required at the drop terminal. Of course, powered drop terminals with active splitters and other equipment may also be provided, as mentioned above. Additional optical signals and / or electrical power and / or communications signals may also be carried in the preterminated cable units.

[0037] From this example of Figure 2, it will be appreciated how signals can be carried between drop terminals using preterminated cable units from a pre-fabricated cable assembly of the type illustrated in Figure 1. It will be appreciated that a realistic deployment involves many more than one drop terminal but the structure and method already described our repeatable to create, at least in principle, any size of network. Example methods of deployment for multiple drop terminals will be described further below, with reference to Figures 8 and 9. Before that, we will present further practical examples of cable assembly structures that may be used in such methods.

[0038] EXAMPLE CABLE ASSEBLIES WITHOUT SHELL

[0039] Figure 3 illustrates in cross-section part of a cable assembly 300 comprising only preterminated cable units within a simple supporting structure. The cross section in Figure 3 is taken at a point within the overall length of the cable assembly, where a first cable unit 102 overlaps in length with a second cable unit 102'. Purely for the sake of example, each cable unit is shown as having a single optical fibre, surrounded by buffer layers, strength members and outer reinforced jacket. The skilled person will appreciate that a wide variety of cable types are possible, and these may include two or more fibres in practice. As a particular example, multifibre drop cables with so-called MPO connectors may be considered. These connectors can connect a number of fibres in one operation.

[0040] In the example cable assembly 300, the supporting structure of the cable assembly is provided by a simple sheath 122, or alternatively a binding of a tape or yarn. This sheath or binding may be continuous along the entire length of the cable assembly or it may be intermittent, sufficient to retain structural integrity and the relative longitudinal arrangement of the cable units and the connectors. It will be understood that the diameter of the cable assembly in this example will be greater at locations where one of the connectors 114, 116 is to be found. This larger dimension of connector 116 is illustrated in broken lines, by way of illustration. At other points along the length of the cable assembly, where there is no overlap between successive cable units, the cross-section of the cable assembly may be substantially that of a single cable unit. It will be understood that such portions constitute the majority of the length of the cable assembly, in a typical example, while the drawings and description in the present disclosure concentrate naturally on the more "interesting” portions of the cable assembly, parts where there is overlap and connectors.

[0041] Figure 4 illustrates another example cable assembly 400, which has a series of cable units one and two, 102' in the same manner as Figure 3. In addition to a sheath 122 or binding, a structural element 124 is provided within the assembly. This structural element 124, which may be a fibre reinforced plastic rod, or a tensile yarn, may extend the entire length of the cable assembly 400. Accordingly, bending forces and tensile forces that are imposed on the cable assembly during, installation and operation can be absorbed by the supporting structure, protecting the cable units themselves from damage.

[0042] In the example cable assembly 300 and 400, it will be appreciated that the sheath 122 or binding may need to be cut in order to access the connectors and to break out the overlapping portions of the cable. In the case of a continuous sheath, this may be something that is extruded over the preterminated cable units in a continuous process, or it may be heat shrink sleeving applied only at certain parts of the cable assembly.

[0043] EXAMPLE CABLE ASSEMBLIES WITH SHELL

[0044] There will now be described various examples of cable assemblies, in which the supporting structure 120 is provided by a continuous structural component that forms a shell of the cable assembly. Compared with a thin sheath or binding, this shell may be semi-rigid and have its own structural integrity. Conveniently, the structural component provides one or more cavities that are only partially enclosed, and these may be referred to as "external cavities". The external cavity or cavities may have side openings through which cable units and connectors can be inserted or withdrawn after the structural component has been manufactured. Plastic extrusion is a very convenient process by which continuous lengths of structural components can be manufactured, having complex cross-sections of the types described below.

[0045] In the illustrated examples, two external cavities are provided along opposite sides of the structural component. This allows two of the preterminated cable units to run in parallel along a given portion of the overall length, without sharing a cavity. More external cavities may be provided in other examples, or only one external cavity. Where multiple preterminated cable units extend in parallel over a given portion of the overall length, they may be arranged in respective individual cavities, or two or more preterminated cable units may share a cavity with one another.

[0046] Figure 5 shows a first such example cable assembly 500, again in a portion where two of the preterminated cable units 102 and 102' are overlapping. As a simple example, each cable unit 102, 102' in this example is shown containing a single optical fibre at its centre. It will be understood that cable units in practice may contain multiple optical fibres, for example 2 optical fibres, or up to 12, 24, 36 or more optical fibres. Where a cable unit has multiple optical fibres, the connectors terminating such cable units may provide connection to one or two or more of those optical fibres, as desired. In this example, the supporting structure includes a structural component 522 that extends continuously along the overall length of the cable assembly. The structural component comprises an extruded profile having outer portions 522a that form a shell of the cable assembly, and a connecting portion 522b. Any suitable material maybe used to form the structural component 522, for example high-density polyethylene [HDPE] extruded in a conventional manner, through a suitably formed tip and die arrangement. In this example, a longitudinal strength member 524 is also integrated into the structural component 522, for example during extrusion. It will be understood that this structural component can be formed in unlimited lengths, in advance of assembling any particular cable assembly.

[0047] The outer portions 522a of the structural component partially enclose two cavities that extend in parallel along the length of the cable assembly, separated by the connecting portion 522b. The first cavity 526 houses a first subset of the series of preterminated cable units, including for example cable unit 102. The second cavity 528 houses a second subset of the series of preterminated cable units, including for example the overlapping cable unit 102'.

[0048] As mentioned, in this example, the cavities 526 and 528 are only partially enclosed, because the structural component 522 on each side is formed with a longitudinally extending opening 522c. The outer portions 522a of the structural component are deformable to allow these openings to be widened to admit the preterminated cable units and the connectors so that they can be stowed and / or removed without cutting material of the shell. (For the avoidance of doubt, this does not exclude that the material of the shell is cut as part of its initial manufacturing process. See examples below.]

[0049] It is a matter of design choice, whether the cable units 102 and the connectors 116 / 114 can be accommodated entirely within the cavities without deformation of the outer portions 522a, or whether the outer portions remain deformed, at least in the portions of the length where the connectors 114 / 116 are housed. That is to say, it is an option to make a cable assembly with a uniform cross-section along its entire length, or to make it with a more compact cross-section than the one illustrated in Figure 5, but allow the shell to bulge, in portions where a connector 114 / 116 is accommodated. It is also to be understood that the term "cavity” is used herein to refer to any space in which the preterminated cable units can be securely accommodated, and does not imply any particular degree of enclosure. The space forming the "cavity" may be completely surrounded by the structural component, or more than 50% surrounded. In Figure 5, an outer wrap or binding 540 is indicated in broken lines, that can be added around the whole cable assembly, or at selected portions, for example to retain the connectors. Depending on the dimensions of the opening and the stiffness of the material forming the shell, the connectors and / or the lengths of cable units may be held sufficiently tightly that the cable units are captive and further binding is not required, or is only required in a limited form. For some applications, it will be convenient if the cable units and connectors are held relatively loosely within the supporting structure. This may be the case, for example where the cable assembly will be installed in a duct. In such a case the cable units and connectors may be held loosely enough that the overlapping ends can be withdrawn from the cavities 526, 528 simply by pulling on the cables 102, 102' at an access point midway along the overlapping portions, rather than "peeling" it sideways through the side opening.

[0050] In principle, the cavity where the cable units are held could be a relatively shallow recess, where the cable units are less than 50% surrounded. In such a case, additional binding, sheathing or even adhesive may be deployed along some or all of the length of a cable unit, to keep it in place.

[0051] Referring to Figure 6, another example 600 has a form similar to but accommodates at least one functional cable element 630 within the supporting structure, in addition to the overlapping preterminated cable units. Reference signs in this drawing correspond to like- numbered features in Figure 5, but with prefix '6' instead of '5'. The functional cable element 630 may extend along the entire overall length of the cable assembly. In this example, a third cavity 632 is formed integrally with the connecting portions 622b of the structural component 622 and the functional cable element 630 lies within the third cavity. To manufacture such a product, the functional cable element may be fed through the extrusion head at the time of making the structural component 622, or it may be inserted afterwards, for example by pulling, or blowing or any suitable method.

[0052] Purely for the sake of example, the functional cable element 630 in this example is illustrated as a conventional "loose tube” type of fibre optic cable. As is well known, such a cable includes a number of unit tubes containing optical fibres (and optionally electrical conductors] arranged around a central strength member, all surrounded by an extruded sheath. The skilled person will recognise that the various cable elements are not drawn to scale, in this or any other drawing.

[0053] As mentioned already, the lengths and the configuration of cable units can be tailored to every individual installation. It may be noted that the external cavities 626 and 628 need not contain preterminated cable units at all points along their length. There may be portions of the overall length in which only a functional cable element 630 is carried. Likewise, there may be portions of the overall length in which the third cavity 632 is empty. The same applies of course in the example of Figure 5.

[0054] It will be seen that the structural component 622 in the example cable assembly 600 effectively comprises an extruded shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile. Some of the cavities are only partially enclosed and accessible from outside the cable assembly (deforming the shell if necessary to open the cavity]. These cavities may be referred to as external cavities in which at least a subset of the series of preterminated cable units are housed. Other cavities such as third cavity 632 may be fully enclosed, and may be referred to as internal cavities. It may be advantageous if the cable units and connectors are held relatively loosely within the cavities 626, 628, in the same way as discussed above in relation to cavities 526 and 528 in Figure 5.

[0055] Figure 7 illustrates a further example cable assembly 700. Features in Figure 7 have the same reference numbers as in Figure 6, but with prefix '7' instead of '6'. Although it has a different shape, in concept, cable assembly 700 has the same general form and function as cable assembly 600, and it has two external cavities 726 and 728. The main difference in this example is that it has not one but six internal cavities 732.

[0056] This example illustrates how, in a given cable assembly, an internal cavity may be left empty (as at the top left], or it may be used to house a functional cable element. In some of the cavities, it will be seen that a microduct 734 is contained within the cavity as another example of a functional cable element. The term "microduct” in this context refers to any small conduit, for example having an outer diameter 16 mm or less. Typical microduct sizes include 7 / 4 mm and 5 / 3.5 mm, where the first number represents the outer diameter and the second number represents the inner diameter of the microduct. In the illustrated example cable assembly 700, all of the four microducts 734 at the same inner and outer diameter. Depending on the application, different microduct sizes may be included in the cavities, and the cavities themselves may have different sizes to accommodate different functional cable elements. The microducts 734 may be inserted through the extrusion head in the process of forming the structural component 722. Such a form of product and its method of manufacture can be similar to well-known tube bundle products, available from the present applicant and others. In the illustrated example, the microducts 734 at upper middle and upper right carry miniature optical fibre cables 736. These miniature cables may be installed in the microducts after manufacture of the structural component 722, for example by blowing, or they may be contained already in the microducts at the time of manufacturing the tube bundle.

[0057] Finally, the bottom middle cavity 732 is shown housing a cable 738 on its own, without a microduct. This is another example of a functional cable element and, purely for the sake of example, it is illustrated in this case as an insulated electric cable having three conductors. As mentioned already, any or all of the cable units and / or functional cable elements in the cable assembly may contain only optical conductors, only electrical conductors, or a mixture of optical and electrical conductors in the same cable element.

[0058] Figure 8 illustrates a modified cable assembly 700', in which structural component 722' similar to the structural component 722 of Figure 7, but with a modified cross section. The internal cavities 732' are shown empty for simplicity, but may be populated by various functional cable elements in the same manner as illustrated in Figure 7. In this example, the various portions 722a' and 722b' are formed so that the openings of the "external" cavities 726' and 728' are held closed by the stiffness of the connecting portions 722b' as seen in Figure 8 (a). Then, to insert or withdraw a cable unit 102 / 102', the shell portions are prised apart to form an opening 722c', as seen at the left-hand side in Figure 8 (b). After insertion, the shell closes again to contain the cable unit securely, as seen on the right-hand side. The opening may stay partly open, in the region of the connectors 114, 116, depending on the relative size of the connectors and the cavities. The opening may even stay partly open along the whole length of a cable unit, depending on the relative size of the cables and the cavities.

[0059] Rather than being extruded with longitudinal openings, a structural component 722' such as the one illustrated in Figure 8 could be extruded, and then cut longitudinally to form openings 722c. In either case, it may be advantageous for the dimensions and stiffness of the shell to be such that the ends of the overlapping portions of neighbouring cable units [including any connector] can be withdrawn by pulling on the cable unit at a midway access point, rather than being "peeled" out through the side opening.

[0060] While the above examples include a supporting structure defining multiple cavities, a supporting structure housing all of the cable units within a single cavity may also be envisaged. Such an example is illustrated in the cable assembly 900 of Figure 9. The structural component 922 may take the form of a simple tube, with a longitudinal opening. Rather than being extruded with longitudinal openings, a structural component 922 such as the one illustrated in Figure 9 could be extruded, and then cut longitudinally to form opening 922c.

[0061] MANUFACTURE OF THE CABLE ASSEMBLIES

[0062] Advantageously, the cable assemblies (100, 300, 400, 500, 600, 700, 700', 900] can be made by first preparing a series of preterminated cable units 102, 102' (jumper cables] by cutting appropriate lengths of cable and fitting each one with a first connector 114 at a first end and a second connector 116 fitted at a second end. After the cable units are all prepared, the method continues with arranging the series of preterminated cable units within a supporting structure in such a way that successive cable units extend over different successive portions LI, L2, ...Ln of an overall length Lo of the cable assembly, as described above.

[0063] For examples having functional cable elements (130, 630, 734, 736, 738, 930], these may be assembled within the supporting structure before the series of preterminated cable units are added. One or more functional cable elements may be incorporated within the supporting structure during extrusion of the structural element 522, 622, 722, 722'. In examples where a functional cable element comprises a microduct

[0734] , optical and / or electrical conductors (736, 738] may be installed within said microduct before or after the series of preterminated cable units are added. The microduct may be incorporated within the supporting structure as part of an extrusion step that forms the structural component. EXAMPLE METHODS OF USING THE CABLE ASSEMBLIES

[0064] Figure 10 illustrates schematically how the cable assembly 100 of the type described above can be used to facilitate the deployment of network connections throughout a neighbourhood area. A typical application is to create a distribution network providing optical fibre broadband connections to homes and / or business premises in a neighbourhood. As mentioned already, this is only one application example, and the method illustrated is readily adaptable to the distribution of communications and / or power signals to a wide variety of drop terminals. Particular examples include, for example, 5G or Wi-Fi access points. Likewise, instead of a neighbourhood of individual user premises, the methods can be adapted for the distribution of communications and / or power signals over an industrial or academic campus, and within large internally within multi-dwelling residential buildings. As mentioned above, the cable assembly can be installed along a desired route. This route may extend above and / or below ground, and the drop terminals may be located below ground, at ground level or at an elevated position on a utility pole, on a building facade, or within a utility space internal to a building.

[0065] Within the cable assembly 1000, three representative preterminated cable units are labelled 102, 102' and 102". The second end of one cable unit overlaps the first end of another cable a subsequent cable unit, in the manner described above. Referring to these three cable units as the first, second and third cable units, it will be understood that these are labels for the purposes of the description, and do not mean that there are not other cable units and user terminals before and after these three. Indeed, a preceding cable unit can be seen entering at the left of the drawing.

[0066] For the purposes of this description, there are shown three drop terminals it being understood that these may represent potentially far more drop terminals over a large deployment area. Each drop terminal has the same general form as the one shown in Figure 2 and described above. Each drop terminal distributes signals between a cable assembly 100 and a respective group of user premises represented schematically in the drawing. The middle one of the three drop terminals is designated as the first drop terminal 200 for the purposes of the following description, and the right-hand one is designated as the second drop terminal 200'. Some enlarged detail of the first and second drop terminals is shown in the upper part of Figure 10, but reference may be had to Figure 2 for more detailed description. In this example, the connections and functions within the first drop terminal 200 are in principle the same as the connections and functions described above with reference to Figure 2. However, multifibre cable units and connectors are exploited to extend the capabilities of the network, as will now be described.

[0067] Cable assembly 1000 in this example can have in principle the form of any of the example cable assemblies described above and illustrated in Figures 1 to 7. The example method of Figure 10 does not rely upon any additional functional cable element 130 being provided within the cable assembly or adjacent to it, but that does exclude the possibility that functional cable elements are provided, of course. On the other hand, the example method of Figure 10 does rely on the individual preterminated cable units and their connectors being of the MPO type, carrying a number of optical fibres which are connected and disconnected in parallel the connectors 114, 116 at the ends of each cable unit. In the upper part of Figure 10, two of the individual fibres are labelled fl, f2 for future reference. As described already above, instead of using MPO cables and connectors communications may be established on a single fibre, or connections may be made to a duplex pair of fibres, not separately illustrated here.

[0068] To make connections to the group of premises supplied by first drop terminal 200, the overlapping ends of the first cable unit 102 and the second cable unit 102' are broken out of the cable assembly 100 and both connected to the first drop terminal 200 in the manner described above with reference to Figure 2. The first drop terminal 200 is configured to relay the optical signals received via fibres fl, f2 of the first cable unit 102 into the corresponding fibres of the second cable unit 102’. At the same time, a signal carried on fibre fl is tapped and fed to the input of the splitter 206 within the first drop terminal 200, exactly as described above with reference to Figure 2.

[0069] Likewise, further along the route of the cable assembly 1000, the overlapping ends of the second cable unit 102' and the third cable unit 102" are broken out of the cable assembly and both connected to the second drop terminal 200’. The second drop terminal 200' is configured to tap fibre f2 to obtain an input signal for the splitter 206' in the second drop terminal 200'. In this way, user terminals connected to the second drop terminal 200' share a fresher signal, that has not been weakened by distribution to premises at the preceding drop terminals. The second drop terminal 200' accordingly provides what may be termed a "recharge point" along the route of the cable assembly. As and when the signal on f2 becomes weakened at a subsequent drop terminal, another fibre f3 can be tapped and so on. The skilled person will appreciate that many different configurations of the drop terminals are possible, exploiting the multiple fibres within the preterminated cable units to make efficient use of their signal-carrying capacity. Redundant optical fibres may also be exploited at a later date, in case of problems in signal strength, or damage, or to expand the network with additional drop terminals.

[0070] Figure 11 illustrates another method of providing a recharge point along the route of a cable assembly 1100. This method exploits a functional cable element 1130, which extends within the cable assembly 1100. The functional cable element may be carried within the cable assembly, as described above with reference to Figures 1, 2, 6,7, 8 or 9, just by way of example. Alternatively, and not illustrated, this functional cable element 1130 may be external to the cable assembly, running in parallel to it, or being routed from a distribution point elsewhere. Again, for the sake of example only, it is assumed that all signals are optical signals, and the cables are optical fibre cables. Alternatively, or in addition, signals may be electrical communication signals or power signals, and the cables and connectors may include electrical conductors and connectors accordingly. Splitters in the used at drop terminals are assumed to be passive splitters, but they may equally be powered. Other types of terminal such as Wi-Fi and 5G access points likewise will be powered, and such power can be delivered conveniently and even through the same preterminated cable unit as optical data signals, if desired.

[0071] In this example, a first cable unit 102 and a second cable unit 102' are connected to first and second drop terminals 200 and 200' in the same manner as in the previous examples. For this example, the preterminated cable units may be single-fibre or dual-fibre cables and connectors as described above with reference to Figure 2, or they may be multi-fibre cables and connectors as described for Figure 10. Either way, in this example method, a first connector of the third cable unit 1102 is not connected to the second drop terminal 200', but rather to a separate recharge terminal 1150 stationed at an appropriate point along the route of the cable assembly. The recharge terminal is configured to inject a new signal into the third cable unit, rather than relaying a signal received from a preceding cable unit 102'. The new signal in this example is extracted from the functional cable element 1130 that extends in parallel with the cable units 102, 102' etc.. In the prefabricated cable assembly, as manufactured, a fourth preterminated cable unit 1102' has its first end overlapping the second end of the third cable unit 1102. Note that the first end of the third cable unit 1102 may not be overlapping the second end of the second cable unit 102', because they are not going to be connected to the same drop terminal.

[0072] As part of the deployment method, the second end of the third cable unit 1102 is broken out of the cable assembly and connected to a further drop terminal 11200. A first end of the fourth cable unit is broken out and connected to the further drop terminal 11200. The form and configuration of the further drop terminal 11200 can be identical to that of the first drop terminal 200. In this way, the third and fourth cable units effectively serve as new first and second cable units for feeding yet further drop terminals along a route of the cable assembly.

[0073] It will be understood that the functional cable element 11 0, if it is included within the cable assembly 1100, needs to be broken out in the vicinity of the recharge terminal 1150. Considering as examples the forms of cable assembly illustrated in Figure 6 and 7, this breaking out operation may involve cutting the structural component 622, 722 to gain access to the cable within. Where the functional element is a microduct 734, this microduct can be cut or branched out of the supporting structure. Where a conduit such as a microduct is broken out, additional lengths of conduit may be used to protect the cable between the cable assembly and the recharge terminal 1150.

[0074] From this example, the skilled person will understand that a cable assembly of the general type disclosed herein enables a wide variety of convenient methods to distribute optical communications, electrical communications, and / or electrical power in a wide variety of network configurations. So that optical different optical signals can be used to supply different subsets of the user terminals throughout the network, maintaining signal quality. In a real network, recharge points can be provided using a combination of the methods of Figure 10 and Figure 11, and / or other methods as desired.

[0075] CONCLUSION

[0076] Cable assemblies of the general type disclosed herein, and methods of deployment similar to those disclosed herein enable deployment in a flexible manner, and with a very low cost and easily manufactured cable assembly. Such cable assemblies can be manufactured using conventional techniques and standard components, while being prefabricated in an arrangement that is completely customised to a given deployment project. Depending on the construction, such cable assemblies can be laid along the desired route by direct burying, and / or pulling through pre-installed conduits. Such cable assemblies can be installed aerially, between utility poles, and / or fixed to building facades, and / or within utility spaces of larger buildings. While cable units in the examples above have been preterminated cable units, the principles disclosed above can also be applied to an assembly in which some or all of the cable units are not preterminated. The cable ends in that case can be bare or fitted with some protection. Suitable connectors can be fitted after the ends are broken out.

[0077] While specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention, defined by the appended claims and their equivalents. It will also be appreciated that features from these different examples can be combined in many different ways to create further embodiment of the invention. Some of these combinations are explicitly mentioned above, while others will be readily envisaged.

Claims

CLAIMS1. A cable assembly (100, 500, 600, 700, 700', 900] comprising a series of preterminated cable units (102, 102'] arranged within a supporting structure (120], each cable unit comprising a length of cable having a first connector (114] fitted at a first end and a second connector (116] fitted at a second end, wherein the supporting structure includes a structural component that forms a shell of the cable assembly, the shell at least partially enclosing a first cavity (526, 626, 726] that extends within the structural component, wherein the first cavity houses at least a first subset of the series of preterminated cable units, and wherein the successive cable units extend over different successive portions (LI, L2, ...Ln] of an overall length (Lo] of the cable assembly, said portions of the overall length overlapping one another such that the second end of a first cable unit in the series overlaps the first end of a second cable unit.

2. A cable assembly as claimed in claim 1 wherein the first cavity is formed with a longitudinally-extending opening such that the preterminated cable units can be inserted and / or removed without cutting the structural component.

3. A cable assembly as claimed in claim 2 wherein the structural component has deformable portions so that the longitudinally-extending opening can be widened to allow the connectors of the preterminated cable units to pass into the first cavity.

4. A cable assembly as claimed in claim 3 wherein, at least in the vicinity of the first and / or second connector, the longitudinally-extending opening remains in a widened state, while the preterminated cable units are housed within the cavity.

5. A cable assembly as claimed in any of claims 1 to 4 wherein the shell of the cable assembly at least partially encloses a second cavity (528, 628, 728] that extends within the structural component in parallel with the first cavity and houses a second subset of the series of preterminated cable units.

6. A cable assembly as claimed in claim 5 wherein, among the cable units of the series of preterminated cable units, the first and second cable units having overlapping portions of the overall length of the cable assembly are housed in different cavities.

7. A cable assembly as claimed in claim 5 or 6 wherein the first and second cavities are arranged on opposite sides of the supporting structure.

8. A cable assembly as claimed in any preceding claim wherein each cable unit of the series of preterminated cable units includes at least one optical fibre for carrying optical signals between the first connector and the second connector.

9. A cable assembly as claimed in claim 8 wherein each cable unit of the series of preterminated cable units includes a plurality of optical fibres, each optical fibre being usable for carrying optical signals between the first connector and the second connector.

10. A cable assembly as claimed in any preceding claim wherein each cable unit includes at least one electrical conductor for carrying power and / or electrical signals between the first connector and the second connector.

11. A cable assembly as claimed in any preceding claim wherein the cable assembly further includes at least one functional cable element (130, 630, 734, 736, 738, 930) within the supporting structure, said functional cable element extending in parallel with two or more of the series of preterminated cable units, optionally along the entire overall length of the cable assembly.

12. A cable assembly as claimed in claim 11 wherein said functional cable element is housed within a cavity of the structural component (122, 622, 722) that extends continuously along the overall length of the cable assembly, said cavity being either the first cavity or a further cavity extending in parallel with the first cavity.

13. A cable assembly as claimed in claim 12 wherein said structural component comprises an extruded plastic shell structure in which a plurality of cavities are defined by cavity walls and connecting portions in a continuous profile, the cavities including at least one partially enclosed external cavity (626 / 628, 726 / 728) forming the first cavity in which at least the first subset of the series of preterminated cable units are housed, and at least one fully enclosed internal cavity (632, 732) in which at least one functional cable element is enclosed.

14. A cable assembly as claimed in claim 12 or 13 wherein at least one internal cavity is pre-populated with optical and / or electrical conductors (630, 736, 738).

15. A cable assembly as claimed in any of claims 11 to 14 wherein at least one functional cable element comprises at least a microduct (734).

16. A cable assembly as claimed in claim 15 wherein, prior to deployment of the cable assembly, at least one microduct within the cable assembly is pre-populated with optical and / or electrical conductors (736, 738].

17. A cable assembly as claimed in claim 15 or 16 wherein at least one microduct [734] is empty for receiving optical fibres and / or electrical conductors at a later time.

18. A cable assembly as claimed in any preceding claim wherein said structural component incorporates a strength member (124, 524, 724] for transmitting tensile forces during installation of the cable assembly.

19. A cable assembly as claimed in any preceding claim wherein the first and second cable units are contained sufficiently loosely that the second end of the first cable unit can be withdrawn from the structural component by pulling on the first cable at an access point midway between the overlapping ends and the first end of the second cable unit can be withdrawn from the structural component by pulling on the second cable at said access point.

20. A cable assembly as claimed in any of claims 5 to 7 wherein the first and second cable units are contained sufficiently loosely that the second end of the first cable unit can be withdrawn from the first cavity by pulling on the first cable at an access point midway between the overlapping ends and the first end of the second cable unit can be withdrawn from the second cavity by pulling on the second cable at said access point.

21. A method of using a cable assembly of the type claimed in any preceding claim, the cable assembly having been installed along a desired route to form part of a distribution network for communication signals and / or electrical power, wherein the second connector (116] of the first cable unit (102] and the first connector (114'] of the second cable unit (102'] are broken out of the cable assembly and both connected to a first drop terminal (200] of a distribution network.

22. A method as claimed in claim 21 wherein the first drop terminal is configured to relay an optical signal received via the first cable unit into the second cable unit.

23. A method as claimed in claim 21 or 22 wherein the first drop terminal is configured to split (204] a first optical signal (fl] received via the first cable into a first plurality of local drop ports (212],24. A method as claimed in any of claims 21 to 23 wherein the cable assembly further includes a third cable unit (102”] arranged such that the second end of the second cable unit overlaps a first end of a third cable unit, and wherein the second connector of the second cable unit and a first connector of the third cable unit are broken out of the cable assembly and both connected to a second drop terminal (200'] of the distribution network.

25. A method as claimed in claim 24 wherein the second drop terminal (200'] is configured to split a second optical signal (f2] received via the second cable unit into a second plurality of local drop ports the second optical signal having been carried by the first cable units in parallel with the first optical signal.

26. A method as claimed in any of claims 21 to 25 wherein the cable assembly further includes at least third and fourth cable units (902, 902'] that extend over further overlapping portions of the overall length of the cable assembly, the method further comprising connecting a first connector of the third cable unit to a recharge terminal (932], the recharge terminal being configured to inject a new signal into the third cable unit, the third and fourth cable units effectively serving as a new first and second cable units for feeding further drop terminals along a route of the cable assembly.

27. A method as claimed in claim 26 wherein the cable assembly further includes at least one functional cable element (930] extending in parallel with the series of preterminated cable units, the second drop terminal (200] being configured to extract said new signal from said functional cable element.

28. A method of manufacturing a cable assembly (100, 300, 400, 500, 600, 700, 700', 900], the method comprising the steps:(a] manufacturing a series of preterminated cable units (102, 102'], each cable unit comprising a length of cable having a first connector (114] fitted at a first end and a second connector (116] fitted at a second end; and(b) arranging the series of preterminated cable units within a supporting structure in such a way that successive cable units extend over different successive portions (LI, L2, ...Ln] of an overall length (Lo] of the cable assembly, said portions of the overall length overlapping one another such that the second end of a first cable unit in the series overlaps the first end of a second cable unit.

29. A method as claimed in claim 28 wherein at least one functional cable element (130, 630, 734, 736, 738, 930] is also assembled within the supporting structure, said functional cable element extending in parallel with two or more of the series of preterminated cable units, optionally along the entire overall length of the cable assembly.

30. A method as claimed in claim 29 wherein said at least one functional cable element is assembled within the supporting structure before the series of preterminated cable units are added in step (b],31. A method as claimed in claim 30 wherein said at least one functional cable element comprises at least a microduct [734].

32. A method as claimed in claim 9 further comprising installing optical and / or electrical conductors (736, 738] within said microduct before or after the series of preterminated cable units are added in step (b].

33. A method as claimed in claim 31 or 32 wherein said supporting structure includes a structural component, and wherein the method further comprises a step (c] of forming the structural component by extrusion before the series of preterminated cable units are added in step (b], and wherein said microduct is incorporated within the structural component as part of the extrusion step (c).

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