Coilable lighting apparatus with bistable mast

Abstract

The invention relates to a lighting assembly (1), comprising an extendible mast (2) constructed and arranged so as to be configurable between a coiled form and an extended form, wherein when extended the mast is resiliently biased in the form of an elongate tube having a slit along its length and wherein when coiled the mast is wound about an axis extending transversely to the longitudinal extent of the mast; and, a lighting element (6) supported by the mast and extending along at least a portion of the mast.

Claims

1. A lighting assembly, comprising: an extendible mast comprising a fibre reinforced composite constructed and arranged so as to be configurable between a coiled form and an extended form, wherein when extended the mast is resiliently biased in the form of an elongate tube having a slit along its length and wherein when coiled the mast is wound about an axis extending transversely to the longitudinal extent of the mast to have a compact form, wherein the mast is stable in both the coiled form and the extended form in that it remains in those respective forms in the absence of any external constraint; and a lighting element that is separable from the mast, wherein the lighting element comprises a flexible sheet supporting one or more light emitting elements, wherein the sheet is configurable as a sleeve and the dimensions in section of the deployed mast and of the sheet configured as a sleeve being provided so that said sleeve can be fitted onto the deployed mast to be supported by the mast and extending along at least a portion of the mast to deploy the lighting assembly for use; wherein when the lighting assembly is not in use, the sleeve is separable from the mast and the lighting element is flattenable and then either foldable or rollable such that the lighting element has a compact form; and wherein when the mast and lighting element are in their compact forms, the lighting assembly is configured for portable storage.

2. The lighting assembly of claim 1, wherein the lighting element comprises plural strips of light emitting elements.

3. The lighting assembly of claim 1, comprising means for fixing the mast to the ground or to a wall or to a ceiling or to an object.

4. The lighting assembly of claim 3, wherein the sleeve is in the form of a strip which has attachment points allowing its longitudinal edges to be joined forming a sleeve to fit around the mast when deployed.

5. The lighting assembly of claim 1, wherein the mast comprises one or more of a fibre reinforced composite and a bistable material.

6. The lighting assembly of claim 1, comprising a connector for connecting the lighting assembly to a power source.

7. The lighting assembly of claim 1, comprising mounting fittings, being one or more of: a top cap for fitting to the end of the mast, by which guy ropes can tether the mast in position on the ground; a bottom cap for fitting to the bottom of the mast and positioning the bottom of the mast on the ground, optionally having a downwardly extending stake for anchoring the assembly in the ground; a tripod or other stand for balancing the assembly on the ground and engaging with and positioning the mast at the desired orientation; a spool for unwinding the assembly from the coiled position to an extended or part extended position; one or more suction cups or magnetic cups for attaching the mast to a vehicle or other wall; or fixtures for attaching the assembly in a horizontal position to a ceiling, wherein the mounting fittings couple to the mast and support the mast in a deployed position.

8. The lighting assembly of claim 1, wherein the connector is a first connector and the assembly comprises a second connector spaced from the first connector by the lighting element, such that the first and second connectors are at substantially opposite ends of the mast thereby allowing a first lighting assembly to connected to a power source via its first connector and a second lighting assembly via its second connector when the first and second assemblies are positioned end-to-end, such that power to the second lighting assembly is received via the first lighting assembly.

9. A lighting assembly, comprising: an extendible mast constructed and arranged so as to be configurable between a coiled form and an extended form, wherein when extended the mast is resiliently biased in the form of an elongate tube having a slit along its length and wherein when coiled the mast is wound about an axis extending transversely to the longitudinal extent of the mast to have a compact form; and a lighting element supported by the mast and extending along at least a portion of the mast, wherein the mast is constructed from a bistable material so as to be stable in both the extended and coiled form without any external housing or constraint being needed to keep the tube in each form, wherein the bistable material comprises a composite formed of plural layers of reinforcing fibre in a matrix material, and wherein the lighting element is permanently mechanically fixed: a) to a surface of the bistable material, or b) between two layers of the plural layers of reinforcing fiber of the bistable material, an outer layer of the two layers being translucent or having one or more cutout portions overlying one or more corresponding light emitting portions of the lighting element to allow light to escape, such that the mast and the lighting element coil together to achieve a compact form for storage or portability.

10. The lighting assembly of claim 9, wherein the lighting element is constructed so as to have a first direction that is relatively more tolerant to stress or strain than a second direction, wherein the second direction is angled relative to the principal axis of the extended mast.

11. The lighting assembly of claim 9, wherein the lighting element comprises plural LEDs embedded into the matrix material.

12. The lighting assembly of claim 9, wherein the connector is a first connector and the assembly comprises a second connector spaced from the first connector by the lighting element, such that the first and second connectors are at substantially opposite ends of the mast thereby allowing a first lighting assembly to connected to a power source via its first connector and a second lighting assembly via its second connector when the first and second assemblies are positioned end-to-end, such that power to the second lighting assembly is received via the first lighting assembly.

13. The lighting assembly of claim 9, comprising mounting fittings, being one or more of: a top cap for fitting to the end of the mast, by which guy ropes can tether the mast in position on the ground; a bottom cap for fitting to the bottom of the mast and positioning the bottom of the mast on the ground, optionally having a downwardly extending stake for anchoring the assembly in the ground; a tripod or other stand for balancing the assembly on the ground and engaging with and positioning the mast at the desired orientation; a spool for unwinding the assembly from the coiled position to an extended or part extended position; one or more suction cups or magnetic cups for attaching the mast to a vehicle or other wall; or fixtures for attaching the assembly in a horizontal position to a ceiling, wherein the mounting fittings couple to the mast and support the mast in a deployed position.

14. A lighting assembly, comprising: an extendible mast constructed and arranged so as to be configurable between a coiled form and an extended form, wherein when extended the mast is resiliently biased in the form of an elongate tube having a slit along its length and wherein when coiled the mast is wound about an axis extending transversely to the longitudinal extent of the mast to have a compact form; and, a lighting element supported by the mast and extending along at least a portion of the mast, wherein the lighting element coils with the mast to achieve a stable coiled form, and wherein the lighting element is loosely coupled to the mast so the lighting element can slip relative to the mast when they extend or coil.

15. The lighting assembly of claim 14, wherein the mast comprises a pocket on a surface of the mast that receives the lighting element such that the lighting element can slip relative to the mast when extended or coiled.

16. The lighting assembly of claim 14, wherein the lighting element is tacked to the surface of the mast to allow relative movement as the mast is coiled and extended whilst keeping its overall position.

17. The lighting assembly of claim 14, wherein the connector is a first connector and the assembly comprises a second connector spaced from the first connector by the lighting element, such that the first and second connectors are at substantially opposite ends of the mast thereby allowing a first lighting assembly to connected to a power source via its first connector and a second lighting assembly via its second connector when the first and second assemblies are positioned end-to-end, such that power to the second lighting assembly is received via the first lighting assembly.

18. The lighting assembly of claim 14, comprising mounting fittings, being one or more of: a top cap for fitting to the end of the mast, by which guy ropes can tether the mast in position on the ground; a bottom cap for fitting to the bottom of the mast and positioning the bottom of the mast on the ground, optionally having a downwardly extending stake for anchoring the assembly in the ground; a tripod or other stand for balancing the assembly on the ground and engaging with and positioning the mast at the desired orientation; a spool for unwinding the assembly from the coiled position to an extended or part extended position; one or more suction cups or magnetic cups for attaching the mast to a vehicle or other wall; or fixtures for attaching the assembly in a horizontal position to a ceiling, wherein the mounting fittings couple to the mast and support the mast in a deployed position.

19. A transportable area lighting installation, comprising: a rectilinear mast, convertible between two states respectively folded or rolled into a compact volume and deployed in a rectilinear tubular configuration in the direction of the axis of the mast; a flexible strip equipped with light-emitting diodes (LEDs), transformable between two states respectively into a winding strip and in the configuration deployed as a sleeve by fixing the two opposite longitudinal edges of the strip; the dimensions in section of the deployed mast and of the strip configured as a sleeve being provided so that said sleeve can be fitted onto the deployed mast; a power supply connected to the light-emitting diodes LEDs and provided with means of connection to a source of electrical energy; and means for temporarily fixing the mast to the ground or to a wall.

20. The transportable area lighting installation according to claim 19, wherein the mast comprises a flexible sheath which can be flattened in a direction perpendicular to its axis and rolled up in the direction of said axis.

21. The transportable area lighting installation according to claim 19, wherein the strip with LEDs comprises on its two longitudinal edges the two corresponding parts of a zipper over substantially its entire length.

22. The lighting assembly of claim 9, wherein the lighting element is permanently mechanically fixed between two layers of the reinforcing fibre, the outer layer of the two layers having plural cutout portions overlying plural corresponding light emitting portions of the lighting element, the outer layer of the reinforcing fibre being overlaid by a translucent layer to allow light to escape.

23. The lighting assembly of claim 9, wherein the lighting element is fixed between two layers of the reinforcing fibre so as to be close to the neutral axis of bending of the bistable member.

24. The lighting assembly of claim 9, wherein the lighting element extends along a first portion of the mast and the mast comprising a cable embodied in the mast along a second portion of the mast which is adjacent to the first portion to connect electrically from an end of the mast to the lighting element.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a perspective view of an example of a lighting assembly in a deployed configuration according to an embodiment of the present invention;

(3) FIG. 2 shows a detail view of a connector for use with the lighting assembly of FIG. 1;

(4) FIG. 3 shows an example of an extendible member suitable for use with the lighting assembly;

(5) FIG. 4 shows an example of a lighting strip as part of a lighting assembly;

(6) FIGS. 5 and 6 show in cross section examples of a lighting strip;

(7) FIGS. 7 to 9 show other examples of deployment of a lighting assembly in the deployed configuration;

(8) FIG. 10 shows in cross section the lighting assembly;

(9) FIG. 11 shows another deployment of a lighting assembly;

(10) FIG. 12 shows in cross section the lighting assembly of FIG. 11; and

(11) FIG. 13 shows another deployment of a lighting assembly.

DETAILED DESCRIPTION

(12) FIG. 1 shows an example of a lighting assembly 1. The assembly 1 comprises an extendible mast 2 incorporating attached or integral lighting element 6 formed from one or more light emitting elements along some or all of its length (shown in hatched line in the example of FIG. 1). References made herein to the longitudinal or axial direction of the mast 2 or lighting assembly generally refer to the direction in which the mast is extended. The mast 2 has a top cap 3 and a bottom cap 4 which attach to the ends of the mast. Optionally, tethers 5 are attached the top of the mast or to the top cap 3 and are pinned to the ground to help anchor the lighting assembly 1 in place. Alternatively, the assembly 1 can be self supporting.

(13) The lighting assembly also has a lighting element 6 attached to or integrally coupled to the mast 2. As shown by the detailed view of FIG. 2, the lighting assembly 1 has a connector 7a by which electrical connection can be made to provide power to the lighting assembly 1 by a cable 8 for connecting the lighting assembly 1 to a power source 9, here a 24 V battery, via a mating connector 7b. Where the connector 7a is at some distance from the lighting element 6, the mast may include a cable 8 to connect the two.

(14) The extendible mast 2 has the form of a STEM (slit tubular extendible member). Thus, as shown in more detail in FIG. 3, the mast 2 is formed of an elongate member of sheet-like material, i.e. the member is thin in cross section, e.g. typically between 1 mm and 5 mm. The member can be opened out into a flat form allowing it to be wound into a coil 17. The extended portion 14 is resiliently biased to have a cross section that is curved, in this example, in the form of a circle or partial circle. Thus when fully extended, the member is resiliently biased in the form of a slit tube. The sides 16 of the tube may meet or overlap to form a full tube, or a gap 13 may be left. Cross sections other than circular may be used. For example, ovals and other continuous, non-circular arcs for the cross section can also be produced. The cross section may have straight portions between curved portions whilst being generally curved.

(15) Thus, with the end cap 3 and bottom cap 4 removed and, where applicable, with the lighting element 6 detached from the mast, the mast 2 can be progressively wound/unwound around an axis perpendicular to its longitudinal extent 19 between a fully coiled form and a fully extended form. If desired, a housing can be provided to contain the coiled lighting assembly and to help guide the extension of the mast. The lighting element 6 either coils with the mast, where permanently attached, or where removed can preferably collapse or rollup to similarly adopt a compact form for storage and transport.

(16) The techniques described herein allow the production of STEM type masts 2 that support the lighting element 6, reducing pack size and often weight and greatly simplifying the deployment of a lighting element. Whilst the techniques could allow the production of mast and lighting element assemblies using any mast 2 that falls into the general category of a STEM, it is anticipated that implementation will in many cases use composites, Fibre Reinforced Plastics (or Polymers) (FRPs) or Bistable Reelable Composite type devices, as their characteristics are well suited to this type of use. Other material, such as polymers with good elastic properties or metals may be used but in general FRP produce a product of superior performance.

(17) FRPs are known per se and are not described in detail herein. However, in brief, FRPs are composite materials made of a polymer matrix reinforced with fibres. The fibres are usually fiberglass, carbon, or aramid, while the polymer is usually an epoxy, vinylester or polyester thermosetting plastic or thermoplastic, such as polypropylene, polyethylene nylon or poly-ether-ether-ketone. Although the use of thermosetting resins has formed the traditional basis for FRP manufacture, thermoplastic matrix polymers are increasingly being used, due to their speed of production and often superior mechanical performance. The matrix is a tough but relatively weak plastic that is reinforced by stronger stiffer reinforcing filaments or fibres. The extent that strength and elasticity are enhanced in a fibre reinforced plastic depends on the mechanical properties of both the fibre and the matrix, their volume relative to one another, and the fibre length and orientation within the matrix. Suitable FRPs may be manufactured by consolidating or laminating different layers of material together.

(18) In the present example, the material used for the mast 2 is bistable, having a first stable form in the slit tube extended form 14 (in which it has a first curvature), and a second stable form when coiled into a coiled form 17 (in which it has a second curvature). Examples of bistable coilable members are disclosed in the Applicant's U.S. Pat. No. 6,217,975 the entire contents of which are hereby incorporated by reference. The member may be constructed with edges as described in the Applicant's U.S. patent application Ser. No. 16/488,116 filed 22 Feb. 2018, the entire contents of which are hereby incorporated by reference, to increase performance of the members. Conventional methods can be used to make the composite or bistable member. Advantageous mechanised production methods of making a composite member are disclosed in the Applicant's 10,124,545B the entire contents are hereby incorporated by reference. Using a bistable member in this way means that the coiled sleeve is stable, meaning that it is easier to handle and store, etc.

(19) In general, the member 1 is manufactured as a fibre-reinforced composite in which various plies of woven, braided or angled fibres 18 (shown in part in FIG. 3) are laid up in a mould or former and heat and/or pressure applied to melt the thermoplastic matrix material consolidate the layers into a composite product. To achieve bistability, at least two plies positioned in the layup towards the intrados 15a and/or extrados 15b faces of the tubular member (i.e. away from the neutral axis of bending of the member), are angled with respect to the longitudinal axis 9 of the product to as to create non-isotropic layers with a high Poisson's ratio. In known examples, a layup of plies with angles of +45, −45, 0, +45, −45 may be used.

(20) Thus, opening out the first curvature of the tube 4 gives rise to tension in the fibres 18 near the intrados face 15a which due to their angle has a component in the longitudinal direction which tends to cause a contraction in this layer in the longitudinal direction. As the tube is opened out to a flatter form, its bending stiffness in a transverse direction decreases. Once the component of the tension arising in the fibres in the longitudinal is sufficient to overcome the bending stiffness it flips the member into having a secondary curvature in the longitudinal direction, i.e. acting to coil the member, and the tension in those fibres is relieved by that layer contracting. A similar effect is produced by the fibres at the extrados face compressing as the tube is opened out, giving rise to a force component in the longitudinal direction in that layer that tends to cause extension in this layer in the longitudinal direction, which again promotes coiling. Thus, due to the orientation of the fibres, as a portion of the slit tube is opened out, it “flips” into a stable coiled form which relieves partially or fully the strains in the fibres and is thus stable. The member is thus reversibly configurable between a stable coiled form and a stable tubular form by progressively flattening and coiling from one end to coil the member, and extending the member from the coil to assume the tubular form.

(21) FIG. 4 shows an elevational view of a lighting element 6 in the form of a flexible strip 21 equipped with light-emitting diodes LEDs in its first strip state, that is to say in its first configuration in two dimensions (more particularly in roll-up strip). FIG. 5 shows the strip 21 in cross section in its second state deployed three-dimensionally in the form of a sleeve. FIG. 6 shows an alternative example of the strip 21 in cross section, in its second state deployed three-dimensionally in the form of a sleeve.

(22) The strip 21 comprises strips of light-emitting diodes LEDs 22 which are generally parallel and longitudinally arranged in ribbon form. In the example of FIG. 5, these strips of parallel longitudinal LEDs 22 light-emitting diodes are fixed to a net 23 or connected to each other by a net 23, which is sewn to a fabric 24 (in particular coated and/or waterproof) based on nylon fibres. The seams 25 allow the assembly of the net 23 to the fabric 24, creating pockets for the LED ribbons 22.

(23) In an alternative example in FIG. 6, these strips of light-emitting diodes 22 parallel longitudinal LEDs are positioned on a flexible support 24′. This flexible support 24′ can be made of a fabric, for example based on nylon fibres. Alternatively or (and preferably) additionally, this flexible support 24′ can be coated and/or waterproof. In this second example, these parallel ribbons of light-emitting diodes LEDs 22 are completed by a film 23′ which is transparent or translucent, which is positioned over the ribbons of light-emitting diodes LEDs 22 as well as over the flexible support 24′, and which is fixed to this flexible support 24′ by fixing means 25′ (in particular constituted by a weld, for example by high-frequency), this between the diode strips 22 and/or on either side of each strip of diodes 22. This flexible support 24′ and this film 23′ then define longitudinal cavities (in particular under the shaped like tunnels) inside which are positioned the strips of light-emitting diodes LEDs 22.

(24) In the example illustrated, there are 26 parallel strips of light-emitting diodes LEDs 22, with a width of about 25 mm and a thickness of the order of 25 mm. The length of the strips may be between 2 meters and 4 meters. However other arrangements are possible. For instance, the number of these parallel strips of light-emitting diodes LEDs 22 can be between 4 and 12, preferably of the order of 8. FIG. 4 shows the two parts 26, 26′ of the zipper with the opening/closing lever 27, which is used for forming the strip into a sleeve around the mast as described below. However other forms of fastening are possible, e.g. hook and loop fasteners at the edges, ties at the edges, “snap” connectors at the edges, etc.

(25) In the lower part of the strip 21 and/or at least one end of this strip 21 (in particular at a lower end of this strip 21), the conducting wires from the LED strips 22 meet to form at least one output cable 8, which is partially hidden and protected by a transverse fold 29 of the fabric 24 or of the flexible support 24′. It is, more particularly, said strip 21 which comprises such a fold 29, more particularly at at least one end of this strip 21, in particular at the lower end of this strip 21. To ensure the protection of the output cable 8 by the fold 29, the latter is closed on said output cable 8. This closure is obtained by folding back on itself said fold 29 and fixing after folding, this by means of a mechanical closure, with which this fold is provided 29, and which consists of a mechanism of the hook type (in particular hook bands) and textile loops, of the type marketed under the name registered as the Velcro trademark.

(26) The lighting assembly thus provides an area lighting system with the advantages of low weight, space requirement and implementation time. In essence, as we have seen before, a sleeve made up of a strip 21 provided with waterproof LED strips 22 is unwound and then fitted onto an extended mast. The mast may then be erected, as shown in FIG. 1, by installing top and bottom caps 3,4, which contain sockets for receiving the respective ends of the mast 2, and then tethering the guy ropes 5 to the ground. Alternatively, as shown in FIG. 7, a tripod 30 support may be provided to attach to and/or support the mast at its proximal end and/or along its length, and stabilise it on the ground 31. Alternatively, as shown in FIG. 8, the bottom cap 4 may have a stake 32 for being driven into the ground 31 to stabilise the mast 2.

(27) Alternatively, as shown by FIG. 9, the assembly 1 may be fixed to a vehicle 35 (e.g. if necessary used to get to the site) by means of suction cups 36 with hooks/elastic ties (not shown), or by means of said at least one magnetic sole (in particular with hooks/elastic ties) or by other mechanical fixtures of a temporary or permanent nature designed for the specific vehicle. Attachment to a vehicle 35 can be done at the rear as on the side, depending on the vehicle, and more particularly depending on the nature of the walls at these locations of the vehicle. The adhesion of suction cups or magnetic soles, operating in pairs linked by elastic links, must be carefully controlled.

(28) Then the connection of the installation allows the power supply forming part of the installation of the invention to supply the strips of LEDs with a supply voltage of, for example, 24 V from the mains via a transformer, or from a battery, or from solar or a portable generator, etc., according to the available supplies.

(29) The assembly and disassembly of the entire installation requires two to three minutes for a single operator, without tools and without special training, the assembly steps resulting naturally from the design of the elements of the system. In essence, the operator unwinds the mast, which stiffens by returning to its tubular shape due to its internal resilient bias of the shell.

(30) Then, the flexible strip 21 with strips of LEDs 22 is placed under the mast 2, so that one of their respective ends are substantially at the same level, and the longitudinal edges of the LED strip are joined and secured to using a zipper whose corresponding parts 26, 26′ cooperate for this purpose. This forms a sleeve around the mast. The sleeve may be held in place via friction, if the sleeve is a snug fit, or ties, hooks, hook and loop or other means of connection may be used to keep the sleeve in position and prevent slip. The main part of the lighting assembly is then made.

(31) The mast 2 is then erected, as described above, and connected to power 9. Thus, as applicable, the guy ropes 5 are pegged out, or the tripod 30 erected and attached to the mast, or the stake 32 driven into the ground. Where suction cups 36 are used to erect the lighting assembly, these may be fixed in pairs oriented substantially horizontally or vertically to a vertical wall, for example of a vehicle 35. The mast is then erected between the hooked suction cups of each pair and attached by means of elastic links cooperating with said hooks, typically elastic bracelets. Where one or more magnetic sole is used, this is fixed to such a vertical wall (for example of a vehicle) while the mast is raised relative to the magnetic sole (in particular between two magnetic soles) and is secured to said at least one magnetic sole (in particular by means of elastic links cooperating with said hooks, typically elastic bracelets). The connector 7 is then mated to the power supply 9 and the assembly is ready for use in mere minutes.

(32) As shown by FIG. 10, the lighting element sleeve 21 may illuminate 360 degrees (or as close thereto as allowed by the fastening means at the edge of the strip of LEDs, e.g. at least 330 degrees). However, other arrangements are possible, for applications where more directional illumination is desired. Similarly, the sleeve is shown over the top portion of the mast. However, the sleeve may extend completely to the lower end of the mast if required.

(33) FIG. 11 shows another example, where the lighting assembly 1 is used in a horizontal configuration, e.g. attached to the ceiling 40 or roof or the top of a tent, etc. The lighting assembly 1 may be mounted by any suitable connection means, e.g. hook and loop straps 42 placed at the ends or periodically along the mast, or mounting brackets, etc. In this example, the light emitting part of the sleeve 21 need not extend completely around the mast, as upward light is largely wasted. For instance, downward illumination through, e.g. 90 to 270 degrees, for instance 180 degrees, may be preferable. A connector may be provided at the distal end of the mast, such that multiple lighting assemblies may be daisy chained together. Thus, the first assembly connects to the power supply, whilst the next assembly connects to the first assembly distal connector, and so on.

(34) The mast 2 is disassembled by following the above mentioned steps in reverse order. Thus, the mast 2 is dismounted, the power 9 is disconnected, and the sleeve 21 detached from the mast (not necessarily in this order). The mast 2 is then coiled into its compact form. Due to the preferred bistability of the mast, no external housing or constraint is needed to keep the tube in this form. The sleeve 21 is preferably also rolled up or folded up to a compact form. In some examples, the mast may be coiled around the rolled up sleeve, thus using the space inside the coil to reduce the overall space taken up. Or vice versa, the sleeve may be coiled around the mast.

(35) In the examples described so far, the lighting element 6 forms a sleeve 21 enveloping the mast 2. However, in other examples, the lighting element 6 may only extend part way around the circumference of the mast, i.e. not bridge the slit in the STEM. The lighting element may be tied on by ties extending around the rest of the circumference, i.e. across the slit, as before. Alternatively, the lighting element may attach directly to the mast 2, e.g. hook and loop between the mast and lighting element, for instance running along the longitudinal edges.

(36) In yet more examples, the lighting element 6 may be permanently fixed to the mast 2 and indeed form an integral part of it. This raises some additional challenges.

(37) As the mast 2 and lighting element/light emitting elements 6 will comprise respectively dissimilar materials, in order to combine the functions of lighting element 6 and mast 2 in a single assembly 1 the dissimilar materials will need to be combined in such a manner that the lighting element 6 is not adversely affected by the repeated coiling and uncoiling of the STEM mast 2. This can be achieved for example as follows: By attaching the lighting element 6 in such a manner as to allow it to slip relative to the material of the mast 2, thus isolating it from the strains occurring at the surface of the mast 2 during coiling and extension By forming the lighting element 6 from a material(s) that is capable of tolerating repeated cycles of extension and retraction

(38) In the case of a lighting element 6 that are loosely coupled, allowing slip relative to the STEM mast 2, any lighting element 6 may be used provided its nature is such that it does not interfere with the coiling of the STEM mast 2. In practice this means that it will usually be formed of a thin material, e.g. flexible OLEDs, strips of LEDs, etc. Whilst there may be a requirement for some thicker elements in the form of LED driving electronics, connectors, etc, that need to be sited close to the lighting element feed point, these need to be localised, such as to form a small, local discontinuity in the coiled profile of the STEM, such as not to interfere with its coiling. Where an electrical requirement may exist for a component with a physical size and shape such that it cannot be rolled interstitially with the STEM, the option exists to site it on the edge of the STEM. Alternatively, these can be positioned at the proximal end of the mast, or off mast where they do not need to be local to the LEDs themselves.

(39) In an embodiment, the outer surface of the STEM 2 has a plurality of transparent or translucent “slats” at intervals along its length, or a fabric or other flexible covering a portion of the length of the mast where the lighting element are desired either continuously or at intervals. The slats or pocket material may be attached at its longitudinal sides to at two points across the STEM 2 such that a pocket (e.g. pocket 77 shown in the assembly 1 of FIG. 13) is formed behind the material, in which the lighting element 6 can be received. To ensure the lighting element 6 does not slip cumulatively over cycles of extension and retraction, one end of the lighting element 6 can be secured to the mast 2. It may be desirable to attach the other end to the mast 2 with an extensible elastic coupling in order to prevent buckling of the lighting element 6 and ensure smooth extension and retraction. In this way the lighting element 6 will be held under tension against the fixed attachment of the other end. Alternatively, the lighting element may be loosely “tacked” to the surface of the mast along its length to permits some degree of movement, whilst keeping the overall position.

(40) If the light emitting elements of the lighting element 6 are to be bonded to the surface of the STEM or to a part of the STEM that is at a significant distance from the neutral axis, then the choice of material needs to be such that the extension and coiling of the STEM will not degrade its performance. It is expected that in most instances the light emitting elements will be at or close to the exterior surface, so the light can be transmitted from the mast. In practice this means using a material that can handle stresses, flex or stretch along the principal axes of the STEM. Conductors needed to form the circuits with the light emitting elements tend not to be extendible, although the substrates they are positioned on may be extensible. The simplest solution to this problem is to use a lighting element where the conductor traces lie at a significant angle relative to the principal axis of the STEM. For instance, where series of individual elements are used, e.g. LEDs, the conductors are orientated at angles to the principal axis of the STEM. The conductors may be mounted to a flexible membrane or directly incorporated into the mast as a substrate. LED elements themselves may be mounted on relatively rigid membrane elements, so as to shield their connections (e.g. soldered to pads on the conductors) from the stresses and strains experienced during rolling/unrolling. In addition, LEDs may be mounted at angles with serpentine conductive paths so that no lengthy part of a conductive trace lies along or transverse to the principal axis (it being appreciated that relatively short portions of conductive trace, e.g. less then 20 mm, may be more able to withstand such forces). For example WO2014186730 (Erogear) provides various methods of attaching LEDs to clothing which protect them against the stresses/strains experienced when applied to a “bendable” material, and these techniques may be found suitable in the present application. FIG. 12 shows an example of a lighting assembly where rows 72 of LEDs are bonded to the surface of the mast.

(41) In other examples, the light emitting elements 6 may be embedded in the STEM structure such that they coincide with or move closer to the neutral axis of bending compared with the surface of the STEM and so are subjected to lower stresses and strains as the mast coils/uncoils as the path length differences between the two states of the BRC STEM are lower. The light emitting elements 6 may be embedded in the matrix of the BRC, e.g. between layers of fibre (where sufficiently translucent to allow light to escape without significant attenuation) or by shifting locally the alignment of fibres to accommodate the elements. Alternatively, the STEM may have partial cut outs for each element.

(42) In most cases, the lighting element 6 will terminate electrically some distance from either end of the supporting STEM mast 2. Although electrical connection can be made to a separate cable 8 at the feed point of the lighting element 6, it is clearly desirable to be able to make this connection at some point convenient to the user. To this end, a cable may be embodied in the STEM mast 2 to connect the lighting element 6 to the connector 7.

(43) One way of accomplishing this by running the cable 78 within a pocket 76 along the edge 16 of the STEM mast 2. By positioning the cable 78 at the edge, any increase in the overall thickness of the structure can be eliminated or kept to a minimum, so its affect on the ability of the mast 2 to coil is minimised. Alternatively, the cable may be positioned on the face of the mast, particularly where relatively thin in order to minimise any distortion during coiling. The pocket may allow some degree of slip of the cable relative to the mast to accommodate path length differences when coiled and extended. Alternatively, if the cable is robust, it may be bonded directly to the mast.

(44) Alternatively, connection to the lighting element 6 can be accomplished by one or more thin conductive elements bonded to the surface of the STEM mast 2 running along its length. Alternatively, connection to the lighting element 6 can be accomplished by one or more thin conductive elements can be embedded within the material of the STEM mast 2 running along its length. These may be sinusoidal, zig zag or otherwise not aligned with the principal axis or transverse axis at a local level so as not to be aligned with the principal directions in which stresses arise on coiling/uncoiling.

(45) The techniques described herein allow the production of STEM type masts 2 that integrate the lighting element function with that of the coilable mast 2, reducing pack size and often weight and greatly simplifying the deployment of lighting systems. As illustrated an example of a lighting assembly made according to the principles disclosed herein has a mast that is 4 meters high having a 7.5 cm diameter, with an elevated lighting element the bottom of which is located 1.5 m from the bottom of the mast. This lighting assembly 1 of FIG. 1 is capable of coiling into a cylindrical space 18 cm in diameter and 25 cm high, and weighs about 4 kg. Other configurations give rise to different packing dimensions and weights, depending on size and mounting arrangements. Other dimensions are possible of the tube are possible. BRC tubes likely to be between 10 mm and 100 mm in diameter and 0.5 m to 4 m in length. The lighting element may produce illumination of 30,000 lumens or more consistent with use to floodlight an outdoor area, although amount of light may be chosen according to the particular application.

(46) The assembly 1 may be provided with a housing 50 which contains the coiled mast 2 from which it can be extended wholly or partially. The housing 50 may form a base for supporting the extended lighting assembly when deployed. FIG. 13 shows a housing 50 that provides a simple “push-pull” cassette, which holds the coil 11 in place and allows the mast 2 to be push-pull extended and retracted. The housing 50 may include a releasable mechanism that constrains the coiled portion 11 of the mast 2, such that releasing the mechanism allows the mast 2 to self coil. The housing 50 may include a hand-operated or motor driven mechanism for winding/extending the mast 2 that is arranged such as to drive the mast 2 between extended 12 and coiled 11 states. For example, a housing 50 comprising a pinch-wheel operable to drive the mast 2. The housing may also provide a connector 7b attached to the cable 78 by which connection is made to the lighting element 6.

(47) Embodiments of the present invention have been described with particular reference to the example illustrated. However, it will be appreciated that variations and modifications may be made to the examples described within the scope of the present invention.