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(11) | EP 2 581 649 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Portable light and portable lighting system |
| (57) A portable light (301) comprising a body (302), a plurality of electric light sources
embedded in said body (302), and a first power supply cable (303) extending from a
first end (304) of said body (302), in which said body (302)comprises a first translucent
light emitting surface (305), and in which said body (302) comprises multi-directional
flexibility along a length thereof such that it is configurable into sinuous shapes,
characterised in that said first power supply cable (303) comprises a connector (306)
at a first end (307) thereof which is alternately usable for releasably electrically
connecting said portable light (301) to a power supply, and for releasably electrically
connecting said portable light (301) to another portable light (301) of the same construction
as said portable light (301).
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[0001] The invention relates to a portable light, as well as to a portable lighting system comprising a plurality of such portable lights, for use particularly but not exclusively in confined work spaces. The invention further relates to the provision of a portable light for use in wet, hazardous and explosive environments.
[0002] It is well known that a correctly illuminated work environment is essential for carrying out tasks, as poor lighting leads to worker discomfort and errors. It is necessary to provide artificial illumination in the work environment, particularly in confined spaces, for example within aircraft, marine or automobile structures, when natural light is not available. Appropriate light levels for working environments are determined by recognised standards; there is a minimum luminance for the task area, i.e. the area where work is being carried out, and a separate minimum luminance level for the surrounding area, i.e. the ambient light level.
[0003] It is known to use point light sources such as a torch or inspection lamp, which are portable and easy to install and handle within a confined space. The light level provided to the work area is generally good. However, the ambient lighting levels which can be provided with a point source are not good, leaving the surrounding areas in darkness. Furthermore, point sources cause shadowing which can interfere with visibility and the light source has to be moved around as tasks are completed.
[0004] An alternative solution is the provision of strip lighting, such as fluorescent tubes. These devices can provide a high level of illumination to surrounding areas. However, fluorescent tubes tend to be difficult to install in confined spaces because they are long and rigid, and if access to the confined space is restricted then it can be impossible to install conventional strip lighting at all. Domestic lighting in the form of a flexible elongate body carrying LEDs is known, but these are not suitable for a work environment because they do not meet any of the require standards, and in any case are not portable and have a limited size and luminance.
[0006] Therefore, according to a first aspect of the present invention a portable light comprises a body, a plurality of electric light sources embedded in said body, and a first power supply cable extending from a first end of said body, in which said body comprises a first translucent light emitting surface, and in which said body comprises multi-directional flexibility along a length thereof such that it is configurable into sinuous shapes, characterised in that said first power supply cable comprises a connector at a first end thereof which is alternately usable for releasably electrically connecting said portable light to a power supply, and for releasably electrically connecting said portable light to another portable light of the same construction as said portable light.
[0007] The term "comprises multi-directional flexibility along a length thereof such that it is configurable into sinuous shapes" as used above to describe a characteristic of the body, is intended to include any construction in which the body can be bent or flexed through at least two planes or about at least two axes at various points along its length, such that it can be configured into three dimensional sinuous shapes which can be appropriate for the work environment in which it is being used. This feature could be achieved with a plurality of separate joints disposed at mid points along the length of the body, each of which provide movement about at least one axis. However, this would be a complex arrangement and preferably the body is constructed from a flexible plastics material with a desired degree of resilience along its length which allows it to be bent or flexed to form curves or turns through three dimensions.
[0008] The connector which can alternately be used to releasably electrically connect the portable light to a power supply or to another such light, allows for different lighting systems to be constructed as required. This could be as simple as a single portable light connected to a power supply, but more importantly it also allows for a plurality of such lights to be strung together. In such an arrangement a single electric power supply can provide power to each of the plurality of portable lights.
[0009] As described further below, a plurality of portable lights according to the invention may be connected in series in this way, but they can also be connected in parallel if desired, or several can branch from a trunk cable.
[0010] In order to allow for a plurality of the portable lights to be connected together in series a second power supply cable can extend from a second end of the body, which can be usable for releasably electrically connecting the portable light to another portable light of the same construction as the portable light.
[0011] In some work environments light emitted in a first direction can fail to adequately illuminate the space, and can cast unwanted shadows. Therefore, in one embodiment of the invention the body can comprise a first group of electric light sources embedded therein and a second group of electric light sources also embedded therein, and said body can comprise a second translucent light emitting surface separate from said first translucent light emitting surface. The first group of electric light sources can transmit light through said first translucent light emitting surface, and the second group of electric light sources can transmit light trough said second translucent light emitting surface. In a preferred construction the first and second translucent light emitting surfaces can face in opposite directions from one another, on either side of the body.
[0012] The plurality of electric light sources and said first power supply cable can be connected together with a sealed connector satisfying the ATEX 95 equipment directive.
[0013] To achieve this the plurality of electric light sources can be connected together by wiring which comprises a power input pin for receiving electrical power which is disposed at the first end of the body. The first power supply cable can then comprise a power output pin for transmitting electrical power, which is disposed at a second end thereof, and which can be electrically connected to said power input pin. The sealed connector can then comprise a moulded shell enclosing the first end of the body and the second end of the first power supply cable; the power input pin and the power output pin can reside within a cavity in said moulded shell; the sealed connector can comprise a potting compound filling said cavity; a heat activated mastic can be disposed between said moulded shell and the first end of the body; and, a heatshrink can be disposed around said moulded shell and the first end of the body.
[0014] In any of the constructions described above the body can comprise a flexible polycarbonate strip. The plurality of electric light sources may be Light Emitting Diodes.
[0015] As described above, the portable light of the invention can be combined with other such portable lights to provide a portable lighting system. Therefore, according to a second aspect of the present invention a portable lighting system comprises an electric power supply and a plurality of portable lights as claimed in claim 1, which are in each case alternately releasably electrically connected directly to said power supply, or releasably electrically connected to said power supply via another of said plurality of portable lights which is connected directly thereto.
[0016] The electric power supply can comprise a first transformer connectable to a mains supply, and a backup transformer. The electric power supply can further include a backup battery.
[0017] In an alternative construction the electric power supply can be just a battery, so the portable lighting system can be operated where a mains power supply is not available.
[0018] In one version of the invention the portable lighting system can further comprise one or more clamps adapted to attach one or more of said plurality of portable lights to a surface of an environment to be lit.
[0019] The one or more clamps can each comprise a pair of hand-grips and a pair of jaws, the jaws being biased together by a resilient means.
[0020] In addition, the one or more clamps can each comprise at least one bracket for receiving one of said plurality of portable lights.
[0021] Embodiments of the present invention will now be described by way of example, and with reference to the accompanying drawings, in which:
Figure 1 is a schematic view of a wing section and prior art lighting equipment;
Figure 2a is a schematic view of a portable lighting system according to the second aspect of the present invention;
Figure 2b is a schematic view of a portable lighting system according to the second aspect of the present invention;
Figure 3 is a perspective view of a first portable light according to the first aspect of the present invention;
Figures 4a, b, c and d are schematic side views of a part of the portable light as shown in Figure 3;
Figure 5 is a schematic view of a power supply arrangement for the portable lighting system as shown in Figure 2a;
Figures 6a, b and c are schematic views of three ways of connecting together portable lights according to the first aspect of the present invention, to form portable lighting systems according to the second aspect of the present invention;
Figures 7a and b are perspective views of clamps for use in a portable lighting system according to the second aspect of the present invention;
Figure 8a shows portable lights suspended from clamps in a parallel configuration of a lighting system according to the second aspect of the present invention;
Figure 8b shows portable lights suspended from clamps in a "U" shaped arrangement of a lighting system according to the second aspect of the present invention;
Figure 8c shows portable lights suspended from clamps in a "G" shaped arrangement of a lighting system according to the second aspect of the present invention.
Figure 9 is a perspective view of a second portable light according to the first aspect of the present invention;
Figures 10a and b are perspective views of a third portable light according to the first aspect of the present invention; and
Figure 11 is a perspective view of a fourth portable light according to the first aspect of the present invention.
[0022] Therefore, as shown in Figure 3, a portable light 301 comprises a body 302, a plurality of electric light sources (not visible) embedded in said body 302, and a first power supply cable 303 extending from a first end 304 of said body 302. The body 302 comprises a first translucent light emitting surface 305, which as is clear from Figure 3 extends along the length of the body 302, and in cross-section comprises a domed shape. As described further below, the body 302 comprises multi-directional flexibility along a length thereof such that it is configurable into sinuous shapes. The power supply cable 303 comprises a connector 306 at a first end 307 thereof, which, as is also described further below, is alternately usable for releasably electrically connecting the portable light 302 to a power supply, and for releasably electrically connecting the portable light 302 to another portable light 302 of the same construction as the portable light 302.
[0023] Referring back to Figure 1, this shows a typical working environment having a restricted space. In this example it is a wing-structure of an aircraft, however the present invention can be used in any applications where artificial lighting is required. In Figure 1, an enclosed box-like structure 100 of a wing section is shown with a small port 101 permitting access to the interior of the box 100. A conventional inspection lamp 102 can be installed in the box 100 because it is small. However, it casts a focussed light on the work area only and causes shadowing. A strip light 103 is shown that would provide sufficient ambient light within the box 100, but it is too long to pass through the port 101 and fully enter the box 100.
[0024] The portable light 301 shown in Figure 3 overcomes these difficulties. The body 302 has embedded within it a line of light emitting diodes (LEDs) (not visible) connected in parallel. They are encapsulated within a solid polycarbonate extrusion to form the body 302. This type of lighting line is commercially available from Cooper Lighting under product code FS4. It contains 72 SMD LEDs per meter and is manufactured as a continuous length. The length has cut points every 100mm, so as shown in Figure 3, it can be down to size as required. The cross-sectional dimensions of the length are 15mm width and 27mm height. Input voltage is 24V DC and power consumption is 9.4 W/m.
[0025] At the first end 304 and a second end 308 of the body 302 there are sealed connectors 309 and 310 respectively, which connect the LED wiring inside the body 302 with the first power supply cable 303, and with a second power supply cable 311 at the second end 308 of the body 302. In each case the power supply cables 303 and 311 are terminated with a Souriau (RTM) connector 306 and 312 respectively. It will be appreciated that these are manually releasable connectors.
[0026] Conventionally, a joint for joining a power supply cable to the internal wiring of a light comprises something as simple as a connector shell which is glued to the body of the light to protect the metallic connections within. A problem with such a joint is that if it is pulled or flexed at the connection point the glue can crack and water can seep into the connection. This increases the risk of sparking. The present invention provides instead a sealed connector which is acceptable for use in an explosive environment, for example inside a fuel tank. An industry standard for this is ATEX certification, where the sealed connector must meet the ATEX 95 equipment directive, and that is the case here.
[0027] In particular, referring to Figures 4a to 4d, these show the various layers of the sealed connector 309. The LEDs inside the body 302 are connected together by wiring which comprises power input pins 401 and 402 for receiving electrical power. These pins 401 and 402 are pushed into the end 304 of the body 302 to make contact with the wiring within. Metal wire ends 403 and 404 protrude from a second end 405 of the first power supply cable 303, and are soldered to the power input pins 401 and 402. A moulded shell 406 encloses the first end 304 of the body 302 and the second end 405 of the first power supply cable 303, which provides structural support for the sealed connector 309. It also defines a cavity 406 in which the pins 401 and 402 and the wire ends 403 and 404 reside. The moulded shell 406 is fabricated from a thermoplastic material. A small hole (not visible) is drilled in the shell 406 to allow for the injection of a silicon potting compound 407 which encapsulates the electrical connections. As shown in Figure 4c, a heat activated mastic tape 408 is wrapped around the sealed connector 309, and in particular is disposed between the moulded shell 406 and the first end 304 of the body 302. Finally, as shown in Figure 4d, a heatshrink 409 is provided which covers the mastic tape 408, and the first end 304 of the body 302.
[0028] When heat is applied to the heatshrink 409 the mastic tape 408 melts into a liquid that runs into the joint between the moulded shell 406 and the body 302. The heatshrink 409 continuously grips the moulded shell 406 and the body 302. In this way a sealed connector 309 is formed between the body 302 and first power supply cable 303 which is capable of withstanding demanding environmental conditions. The sealed connector 309 has an Ingress Protection (IP) rating of IP68, i.e. capable of preventing any solid material ingress and ingress of water when fully immersed. It is also capable of being used in an explosive environment because there is no risk of sparking from the wiring within the joint. Suitable mastic tape includes DERAY (RTN) Coldmelt tape available from DSG-Canusa Ltd. Suitable heatshrink includes DERAY (RTM) -I, also available from DSG-Canusa Ltd.
[0029] The sealed connector 310 at the second end 308 of the body 302 is of the same construction as the sealed connector 309.
[0030] A plurality of portable lights like portable light 301 can be used create a portable lighting system according to the second aspect of the present invention. Referring to Figure 2a, this shows such a system 200, in which there is an electrical power supply 201, a connecting cable 202, extension cables 203 and 204, and a portable light 301. Referring to Figure 2b, this shows a portable lighting system 205 installed within a wing-section 206 having a number of interlinked compartments 207 to 210. Here the access problems can be clearly seen, and also how the flexible portable lights 301 can overcome these problems. In this arrangement the system 205 includes a power supply line 211, and a number of inter-connected portable lights 301.
[0031] The components of the power supply 201 are illustrated in Figure 5. Two transformers 501 and 502 step a mains input down to 24v. The first transformer 501 is the main transformer which is the transformer in usual operation. The second transformer 502 is a backup transformer which cuts in if the main transformer fails. A battery 503 is also provided as a further backup in case of mains power failure. The battery 503 can provide power to the lighting circuits for up to thirty minutes and ensures that a worker has plenty of time to get out of the workspace in the event of a power failure. An audible warning may be sounded that the system is running on the battery backup, or a visible warning such as a warning light on the power supply 201.
[0032] Figures 6a to 6c show a number of ways lighting systems like 200 and 205 described above can be configured electrically. A basic arrangement is shown in Figure 6a, in which a number of lighting elements 301 are connected in series. This can be done by releasably connecting the connector 312 of the second power supply cable 311 of a first portable light 301 to the connector 306 of the first power supply cable 303 of the next portable light, and so on. Figure 6b shows a more complex arrangement where connecting cable 202 supports two 24v circuits. Connected to cable 202 is a sub-connecting cable 601, where each end of the sub-connecting cable 601 has a spur connection; the first end spur connection carrying spur circuit 1 and the second end spur connection carrying spur circuit 2. The circuits in each case are made up of one or more portable lights 301, so the lights 301 form the spurs. This configuration allows even loading of the power supply 201. Figure 6c shows a further configuration where cable 202 supports four 24v circuits. Here, sub-connecting cables 601 are divided into two types: type A for supporting spur circuits 1 and 2 and having spur connections at each end for connection to spur circuits 1 and 2; and type B for supporting spur circuits 3 and 4 and having spur connections at each end for connection to spur circuits 3 and 4. In Figure 6c several portable lights 301 are releasably connected together in series to form the spur circuits 1, 2, 3 and 4 connected to each spur connection. The skilled person will appreciate that any number of spur circuits may be provided to create an elaborate lighting system which may be adapted for any number of different applications.
[0033] In order to suspend the portable lights 301 above a task area, the lighting system further comprises clamps 700, as shown in Figures 7a and 7b. The clamps 700 are of the sprung-loaded, hand-operated type. Hand-grips 701 are provided which are biased against a spring (not visible). Jaws 702 having flat gripping faces 703 are provided for gripping a feature of the workspace. In the interior of a wing structure this would be an overhead rib or spar. When the hand-grips 701 are squeezed together against the spring bias, the jaws 702 open. The hand-grips 701 are released to close the jaws 702 around a protruding feature of the workspace. The jaws 702 and hand-grips 701 may be fabricated as a one-piece moulding from a hard thermoplastic material or from metal. A soft pad 703 of, for example, silicon may be incorporated into the jaws to protect the feature of the workspace to which the clamp 700 is attached. Brackets 705 or 706 are provided which are shaped to receive the portable lights 301. The brackets 705, 706 may be shaped to receive the portable lights 301 from different directions; perpendicular to the plane of the jaw faces as in Figure 7a, parallel to the jaw faces, or both perpendicular and parallel as shown in Figure 7b.
[0034] As an alternative to the clamps 700, the portable light 301 can be wound around or draped over features in the workspace or simply laid across the floor.
[0035] In order to install the lighting system, the connecting cable 202 of the power supply 201 is fed into the workspace, for example the wing section 206 shown in Figure 2b. Next, the required number of portable lights 301 are fed into the workspace 206. Sub-connecting cables 601, as shown in Figures 6b and 6c, can also be fed into the workspace 206 as required. Suitable positions for the flexible portable lights 301 are selected, which may be along the floor of the workspace, or over-head, or attached to walls. Clamps 700 are then installed in the selected positions. The portable lights 301 may be arranged and configured according to required light levels, for example a straight line in order to emulate the light emitted from a fluorescent tube. Alternatively a portable light 301 may be doubled up to form a "U" shape, or tripled to form a "G" shape to increase the light density. It will be appreciated that these are sinuous shapes which are possible because of the multi-directional flexibility along the length of the body 302. Such usage is illustrated in Figures 8a, b and c respectively. When the clamps 700 are installed, each portable light 301 is clipped into the clamps. The ends of the power supply cables 303 and/or 311 are then releasably connected together accordingly, or the power supply cables 303 are connected to the sub-connecting cables 601, in any configuration like those exemplified by Figures 6a to 6c, so all the portable lights 301 are powered by the power supply 201.
[0036] The portable lights 301 may be used as coils to increase the brightness of light provided in particular areas, or used in lengths to provide ambient lighting. The portable lights 301 provide light from a large range of angles, which minimises shadowing. The flexibility of the portable lights 301 means they are easy to install in difficult to access areas and can be manipulated to fit into small spaces. They are also cool to the touch and therefore do not produce large amounts of heat, which could cause worker discomfort and pose a safety risk. The sealed connectors 309 and 310 allow safe operation even in explosive atmospheres. The lighting system may be easily and conveniently transported. The materials of construction mean that it is robust and is suitable for heavy duty use.
[0037] The embodiments described above can be altered without departing from the scope of claim 1. For example, in one alternative embodiment (not shown) a lighting system may be powered by a battery only, allowing it to be a fully portable and handheld during use.
[0038] In a further alternative embodiment as shown in Figure 9, a portable light 901 is the same as that shown in Figure 3, except that it is provided with only a single connector 902 at one end. An end cap 903 is provided to cap off the opposite end. A single-ended light like this can form a stub in a multiple portable light array, or it can be used on its own connected to a battery for handheld use.
[0039] In a further alternative embodiment as shown in Figures 10a and b, a portable light 1001 is the same as that shown in Figure 3, except that the sealed connectors 1002 and 1003 are over-moulded. In addition, at the second end 1004 of the body 1005, instead of there being a second power supply cable, the connector 1006 is formed into the over-moulding.
[0040] In a further alternative embodiment as shown in Figure 11 a portable light 1101 is the same as that shown in Figure 3, except that the body 1102 comprises a first group of LEDs embedded therein (not visible) and a second group of LEDs also embedded therein (also not visible). The body 1102 also comprises a second translucent light emitting surface 1103 separate from a first translucent light emitting surface 1104. The first group of LEDs transmit light through the first translucent light emitting surface 1104, and the second group of LEDs transmit light trough the second translucent light emitting surface 1103. As is clear from Figure 11, these surfaces 1104 and 1103 face in opposite directions from one another, on either side of the body 1102. The body 1102 is formed by connecting two bodies 302 as shown in Figure 3 together back to back. This is done in such a way that the resulting body 1102 is just as flexible in multi-directions as before. This is illustrated in Figure 11, which shows the body 1102 curved through the vertical and horizontal planes, as well as twisted along its length. The sealed connectors 1105 and 1106 are also over-moulded in a similar manner to as in portable light 1101. Figure 11 does not show the first and second power supply cables, and their connectors, but these would be included.
1. A portable light comprising a body, a plurality of electric light sources embedded
in said body, and a first power supply cable extending from a first end of said body,
in which said body comprises a first translucent light emitting surface, and in which
said body comprises multi-directional flexibility along a length thereof such that
it is configurable into sinuous shapes, characterised in that said first power supply cable comprises a connector at a first end thereof which
is alternately usable for releasably electrically connecting said portable light to
a power supply, and for releasably electrically connecting said portable light to
another portable light of the same construction as said portable light.
2. A portable light as claimed in claim 1 in which a second power supply cable extends
from a second end of said body which is usable for releasably electrically connecting
said portable light to another portable light of the same construction as said portable
light.
3. A portable light as claimed in claim 1 or 2 in which said body comprises a first group
of electric light sources embedded therein and a second group of electric light sources
also embedded therein, in which said body comprises a second translucent light emitting
surface separate from said first translucent light emitting surface, in which said
first group of electric light sources transmit light through said first translucent
light emitting surface, and in which said second group of electric light sources transmit
light trough said second translucent light emitting surface.
4. A portable light as claimed in any of the preceding claims in which said plurality
of electric light sources and said first power supply cable are connected together
with a sealed connector satisfying the ATEX 95 equipment directive.
5. A portable light as claimed in any of the preceding claims in which said plurality
of electric light sources are connected together by wiring which comprises a power
input pin for receiving electrical power which is disposed at said first end of said
body, in which said first power supply cable comprises a power output pin for transmitting
electrical power which is disposed at a second end thereof, and which is electrically
connected to said power input pin, in which said sealed connector comprises a moulded
shell enclosing said first end of said body and said second end of said first power
supply cable, in which said power input pin and said power output pin reside within
a cavity in said moulded shell, in which said sealed connector comprises a potting
compound filling said cavity, a heat activated mastic disposed between said moulded
shell and said first end of said body, and a heatshrink disposed around said moulded
shell and said first end of said body.
6. A portable light as claimed in any of the preceding claims in which the body comprises
a flexible polycarbonate strip.
7. A portable lighting system comprising an electric power supply and a plurality of
portable lights as claimed in claim 1, which are in each case alternately releasably
electrically connected directly to said power supply, or releasably electrically connected
to said power supply via another of said plurality of portable lights which is connected
directly thereto.
8. A portable lighting system as claimed in claim 7 in which said electric power supply
comprises a first transformer connectable to a mains supply, and a backup transformer.
9. A portable lighting system as claimed in claim 8 in which the electric power supply
further includes a backup battery.
10. A portable lighting system as claimed in claim 7 in which the electric power supply
is a battery.
11. A portable lighting system as claimed in any of claims 7 to 10 in which the portable
lighting system further comprise one or more clamps adapted to attach one or more
of said plurality of portable lights to a surface of an environment to be lit.
12. A portable lighting system as claimed in claim 11 in which said one or more clamps
each comprise a pair of hand-grips and a pair of jaws, the jaws being biased together
by a resilient means.
13. A portable lighting system as claimed in claim 12 in which said one or more clamps
each comprise at least one bracket for receiving one of said plurality of portable
lights.