EP3036477A1

EP3036477A1 - Light fitting

Info

Publication number: EP3036477A1
Application number: EP14753283.2A
Authority: EP
Inventors: Daniel HISCOKE
Original assignee: Scolmore International Ltd
Current assignee: Scolmore International Ltd
Priority date: 2013-08-01
Filing date: 2014-07-29
Publication date: 2016-06-29
Also published as: AU2014298256A1; GB201313819D0; CN204268403U; WO2015015145A1

Abstract

A light fitting (10) comprises an outer housing (11) and an inner support (12) which is supported by the outer housing, said inner support comprising a rear face (30) and a front face (31) to which a solid-state lighting device (13) is secured in good thermal contact therewith, the rear face of the inner support being devoid of an attached heat sink and the inner support serving, in use, as the primary heat sink for dissipation of heat generated by the solid-state lighting device. The light fitting may comprise a fire resistan intumescent material to form a fire resistant barrier.

Description

Light Fitting

This invention relates to a light fitting and in particular, though not exclusively, to a light fitting of the type in which a solid-state device is employed to provide a source of light.

The light fitting may be of the so-called adjustable type which allows the direction of emitted light to be adjusted.

The invention relates also, though not exclusively, to a light fitting which may be of the so-called fire resistant type, being resistant to heat and/or fire, and/or which is suitable for installing in an aperture in a partition panel such as that of a ceiling or wall.

For many light fittings, and in particular those installed in a confined space, care must be taken to ensure that there is no undue build up of heat. That is a particularly important consideration in the case of solid-state lighting devices such as LED lights the efficiency and longevity of which is more adversely affected by operation in a high temperature local environment than is the case for incandescent type lighting devices.

To avoid or minimise the risk of the operation of a solid-state lighting device being adversely affected by a high temperature local environment it is known to provide a heat sink and secure the solid state lighting device directly to the heat sink in good thermal contact therewith.

In the case of an adjustable type light fitting the lighting device and heat sink typically are mounted on and supported by an inner support housing which is pivotally mounted relative to an outer housing, such as a fire resistant outer housing. The inner housing is provided with one or more apertures aligned with one or more light emitting devices such that light from the or each solid- state lighting device at a rear side of the support housing travels outwards through a respective aperture. An example of a fire resistant adjustable lighting unit of the kind incorporating an assembly of a solid-state lighting device and heat sink is described in more detail in the specification of our copending UK patent application No. GB 1302348.6.

Although a lighting unit of the type described in the preceding paragraph is found to perform well, there is a continuing desire to reduce manufacturing costs without any significant reduction in overall performance. The present invention seeks to provide an improved light fitting which facilitates a reduction of manufacturing costs without any significant reduction in overall performance.

In accordance with one aspect of the present invention there is provided a light fitting comprising an outer housing and an inner support which is supported by the outer housing, said inner support comprising a rear face and a front face to which a solid-state lighting device is secured in good thermal contact therewith, and said rear face of the inner support being devoid of an attached heat sink.

In accordance with another aspect of the present invention there is provided a light fitting comprising an outer housing and an inner support which is supported within the outer housing, said outer housing comprising a closed end and an open end, said inner support comprising a rear face and a front face to which a solid state lighting device is secured in good thermal contact therewith whereby the inner support serves as a heat sink and wherein the rear face of the inner support is spaced from the closed end of the outer housing whereby a void is defined therebetween.

The light fitting may be of a fire rated type and may be provided with an outer housing of fire resistant material. Thus in contrast to conventional

constructions in which a heat sink is mounted at a rear side of a fire resistant member, namely at a side protected from fire, the present invention teaches provision of that heat sink at the side of the fire resistant material which in use is exposed to occurrence of a fire in the space for which the light fitting provides illumination. Said heat sink may be substantially the sole means for dissipation of heat generated in use by the solid-sate lighting device or it may be a primary heat sink with additional heat dissipation being provided by other components of the light fitting.

Preferably the rear face of the inner support lies substantially midway between the open and closed ends of the outer housing, or closer to the open end than to the closed end.

In accordance with yet another aspect of the present invention there is provided a light fitting comprising an outer housing for locating relative to a support structure such as an apertured partition and an inner support for supporting a solid-state lighting device wherein the inner support comprises a rear face and a front face, said front face facing in the general direction in which emitted light travels from the light fitting, said inner support being secured to the outer housing for at least one of pivotal and rotational movement relative to the outer housing and said solid-state lighting device being secured to said front face in thermal contact with the inner support.

In contrast to a conventional construction of a light fitting in which the outer housing and an inner support are formed from the same material and have substantially the same thickness, preferably the material of the inner support has a greater thickness than the material of the outer housing.

Thus in accordance with a further aspect of the present invention there is provided a light fitting comprising an outer housing for locating relative to a support structure such as an apertured partition and an inner support for supporting a solid-state lighting device, wherein the inner support comprises a rear face and a front face, said front face facing in the general direction in which emitted light travels from the light fitting, said inner support comprising material of a greater thickness than the material of the outer housing and said solid-state lighting device being secured to said front face of the inner support in thermal contact therewith. That is, the spacing of said front and rear faces of the inner support preferably is greater than the wall thickness of the outer housing, preferably more than twice and more preferably at least three times said wall thickness.

Accordingly in comparison with a conventional support for a lighting device and which is required to have a strength merely sufficient to support a lighting device and heat sink, the inner support of the present invention preferably comprises an excess of material whereby it is of a relatively robust

construction which assists in performing a significant heat sink function.

An inner support having one or more of the inner support features described herein may be employed in the construction of either a fixed type and an adjustable type of light fitting.

The inner support may be a casting, moulding or pressing or be of a

laminated construction.

Preferably the inner support is formed from aluminium and more preferably is a casting of aluminium although sheet material and other metals such as steel may be employed.

Preferably the solid-state lighting device of a light fitting in accordance with the present invention is secured to said front face in direct thermal contact therewith.

Preferably the inner support is in good thermal contact with the outer housing whereby heat from the solid-state lighting device is conducted to the outer housing such that the outer housing assists the inner support to function as a heat sink.

For an adjustable type light fitting pivotal or rotational movement of the inner support relative to the outer housing about an axis of pivotal movement or rotation preferably results in relative sliding movement of contacting surfaces which maintain axial alignment of the inner support and outer housing and also surfaces which resist relative movement of the inner support and outer housing in the direction of the length of said axis. The contact between said confronting surfaces thereby assists in transfer of thermal energy from the inner support to the outer housing such that the outer housing is able effectively to serve at least in part as the heat sink.

The means for location of the inner support relative to the outer housing may comprise the combination of confronting, contacting surfaces which are of a cylindrical shape and confronting, contacting surfaces which are substantially planar, such as of an annular shape. The area of the contacting planar surfaces may be greater than that of the contacting cylindrical surfaces, and preferably is at least twice the area of the contacting cylindrical surfaces.

As an alternative to a combination of planar and cylindrical contacting surfaces, the location of the inner support relative to the outer housing may comprise part-spherical surfaces, frusto conical surfaces, or a combination of part-spherical surfaces and/or frusto conical and one or more of cylindrical and planar surfaces.

Preferably at least one and more preferably each of a pair of contacting surfaces is formed from aluminium.

The outer housing may be of a substantially tubular shape which is open at one end to facilitate insertion of the inner support and associated solid-state lighting device.

The outer housing may be of a tubular shape which has a major, longitudinal axis parallel with the length of the housing. The inner support may be pivotally mounted about an axis which is substantially perpendicular to said longitudinal axis. Additionally or alternatively the inner support may be mounted for rotational movement about said longitudinal axis of the outer housing. The inner support may be secured to the outer housing by pivot means which comprises two pivot devices located or acting at diametrically opposite positions of a circular section outer housing. The pivot means may comprise a pivot device which extends through an element of fire resistant intumescent material.

The outer housing may be of a fire resistant type, such as a steel housing.

Although some features of the present invention are described in combination with other features of the present invention, it is to be understood that said features may be provided independently of one another or in combinations which differ from those specifically described.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:-

Figure 1 is a perspective view of a light fitting in accordance with a first embodiment of the present invention;

Figure 2 is an exploded perspective view of the light fitting of Figure 1 ;

Figure 3 is a longitudinal sectional view of the light fitting of Figures 1 and 2 in the plane 3-3 of Figure 2, and

Figure 4 is a perspective view of a light fitting in accordance with a second embodiment of the present invention.

A swivel type LED light fitting 10 for inserting into a plasterboard ceiling or wall comprises an outer housing 11 of fire resistant material which provides support for an inner support 12 to which a solid-state lighting device 13 is secured. The outer housing 11 comprises a generally cylindrically shaped central body region 14 which is open at one end region 15 and relatively closed at the other end region 16. The open end, in known manner, is formed integrally with an outwardly extending flange 17. A pair of spring-loaded retention arms 38 extend from the body 14 whereby, in use, the arms bear against the normally hidden side of the plasterboard (not shown) and hold the flange firmly against the other, visible side of the board with a moisture seal 19 held captive between the flange and plasterboard. The arms 38 are attached to spring mounts 20 which in turn are attached to the outer surface of the central body region 14 of the outer housing.

A band of intumescent material 18 extends around that region of the central body 14 adjacent the flange 17 so as to align with the aperture formed in the plasterboard for accommodating the light unit and thereby effect a fire barrier between the light unit and ceiling void. The flange 17 also provides support for a decorative bezel 22 and a bezel seal 23 which is interposed between the bezel and flange 17.

The outer surface of the closed end region 16 of the outer housing 11 provides support for a driver casing 24 which contains, in known manner a driver PCB 39.

The inner support 12 has a rear face 30 which faces towards the closed end region 16 of the outer housing, and a front face 31 which faces outwards in a direction towards the open end region 15 of the outer housing.

The inner support 12 is an aluminium casting of generally circular shape but provided, at two diametrically opposite positions, with pivot supports 25 that provide bearing surfaces 26 for confronting the inward facing surfaces of central regions 27 of the inner housing.

The supports 25 extend from the rear face 30 in a direction towards the closed end 16 of the outer housing. A cylindrically shaped skirting wall 37 extends from the periphery of the front face 31 in a direction towards the open end region 15 of the outer housing.

Each pivot support 25 is provided with a necked recess 36 to locate a pivot pin 28 which extends in an inwards direction from the outer housing central region 27 whereby the support member is pivotally mounted relative to the outer housing for pivotal movement about an axis substantially perpendicular to the major axis of the cylindrically shaped central body 14 of the outer housing 11.

The shape of the necked recesses 36, being narrower at the mouth of each recess than inwards of the recess, allows the inner housing readily to be snap fitted to the pivot pins 28.

In the event of pivotal movement there is relative sliding movement of the contacting surfaces, namely between each annular face 26 and the outer housing central region 27, and between each pin 28 and associated aperture in the outer housing central region 27.

The outer housing is formed from pressed sheet steel, or from aluminium, and in this embodiment of the invention the aluminium casting of the inner support has a thickness of three times the wall thickness of the outer housing.

The aforementioned lighting unit 3 is secured directly to the front face 31 of the inner support 30 in good thermal contact therewith.

The lighting unit 13 comprises an LED array which is sandwiched between the inner support 12 and a PCB shield 32 which is formed with apertures aligned with the LEDs of the lighting unit 13. A Perspex lens 34 extends over the PCB shield 32 and is secured in position relative to the inner support for pivotal movement therewith.

Heat generated by the lighting unit 3 is conducted directly to the inner support 2 which acts as a heat sink. Furthermore, the confronting, contacting surfaces of the inner support flanges 25 and the regions 27 of the outer housing, in addition to the confronting surfaces of the cylindrical pivot pins 28 and receiving apertures in the housing region 27 facilitate effective conduction of thermal energy into the outer housing which thereby also provides a heat sink function and dissipation of heat.

Accordingly the rear face 30 of the inner support 12 is devoid of the conventionally attached heat sink. In consequence the overall height of the light fitting, as considered in the longitudinal direction of the casing 11 , is less than that of conventional swivel type light fittings in addition to eliminating the cost and weight of the conventionally provided separate heat sink.

Although the first embodiment has been described in relation to a swivel type light fitting, the general form of the construction may be employed, with only minor modification, for the provision of a fixed type light fitting. Thus, for example, by providing square section pins and square section openings to receive the pins there may be provided a light fitting of a fixed type.

In accordance with a second embodiment of the present invention (see Figure 4) a light fitting 40 is constructed substantially as in respect of the first embodiment but has a bezel of a different design. In accordance with the second embodiment of the invention the light fitting comprises a bezel 41 which extends radially inwards to have an inner edge 42 of a diameter less than the outer diameter of the aforedescribed inner support 12. In

consequence the bezel inhibits pivotal movement of the inner support thereby providing a light fitting of a fixed type.

Accordingly it will be appreciated that, in addition to the aforedescribed advantages, the present invention facilitates the economic provision of both swivel and fixed type light fittings, or conversion therebetween, by the simple expedient of appropriately selecting the size of the bezel.

Scol5DE3

Claims

1. A light fitting comprising an outer housing and an inner support which is supported by the outer housing, said inner support comprising a rear face and a front face to which a solid state lighting device is secured in good thermal contact therewith, said rear face of the inner support being devoid of an attached heat sink.

2. A light fitting according to claim 1 wherein said outer housing

comprises a close end and an open end.

3. A light fitting comprising an outer housing and an inner support which is supported within the outer housing, said outer housing comprising a closed end and an open end, said inner support comprising a rear face and a front face to which a solid-state lighting device is secured in good thermal contact therewith whereby the inner support serves as a heat sink and wherein the rear face of the inner support is spaced from the closed end of the outer housing to define a void therebetween.

4. A light fitting according to claim 3 wherein the rear face of the inner support is devoid of an attached heat sink.

5. A light fitting according to claim 3 or claim 4 wherein the rear face of the inner support lies substantially midway between the open and closed ends of the outer housing.

6. A light fitting according to claim 3 or claim 4 wherein the rear face of the inner support lies closer to the open end than to the closed end of the outer housing.

7. A light fitting according to any one of the preceding claims and comprising fire resistant material whereby the light fitting provides a fire resistant barrier and wherein the inner support is provided at that side of the fire resistant barrier which, in use, is exposed to the occurrence of a fire in the space for which the light fitting provides illumination.

8. A light fitting according to claim 7 and comprising an outer housing of fire resistant material.

9. A light fitting according to any one of the preceding claims wherein the material of the inner support has a greater thickness than the material of the outer housing.

10. A light fitting according to claim 9 wherein the spacing of the front and rear faces of the inner support is at least three time the wall thickness of the outer housing.

11. A light fitting according to any one of the preceding claims wherein the inner support comprises one or more of a casting, moulding, pressing or a laminated construction.

12. A light fitting according to claim 11 wherein the inner support is an aluminium casting.

13. A light fitting according to any one of the preceding claims wherein the solid-state lighting device is secured to the front face of the inner support in direct thermal contact therewith.

14. A light fitting according to any one of the preceding claims wherein the inner support is in good thermal contact with the outer housing whereby heat from the solid-state lighting device is conducted to the outer housing such that the outer housing assists the inner support to function as a heat sink.

15. A light fitting according to any one of the preceding claims wherein the inner support is secured to the outer housing for at least one of pivotal and rotational movement relative to the outer housing.

16. A light fitting according to claim 15 wherein movement about an axis of said pivotal or rotational movement results in relative sliding movement of contacting surfaces which maintain alignment of the inner support and outer housing and also contacting surfaces which resist relative movement of the inner support and outer housing in the direction of the length of said axis.

17. A light fitting according to claim 16 wherein means for location of the inner support relative to the outer housing comprise the combination of confronting, contacting surfaces which are of a cylindrical shape and confronting, contacting surfaces which are substantially planar.

18. A light fitting according to claim 17 wherein the area of the contacting planar surfaces is greater than that of the contacting cylindrical surfaces. 9. A light fitting according to any one of claim 16 to 18 wherein location of the inner support relative to the outer housing is by means comprising part- spherical surfaces, frusto-conical surfaces or a combination of part-spherical and/or frusto-conical surfaces and one or more of cylindrical and planar surfaces.

20. A light fitting according to any one of claims 16 to 19 wherein each of a pair of contacting surfaces is formed from aluminium.

21. A light fitting according to any one of claims 16 to 20 wherein the inner support is secured to the outer housing by pivot means which comprises two pivot devices located or acting at diametrically opposite positions of an outer housing of a circular cross-sectional shape.

22. A light fitting according to claim 21 wherein the pivot means comprises a pivot device which extends through an element of fire resistant intumescent material.

23. A light fitting comprising an outer housing and an inner support which is supported by the outer housing, said inner support comprising a rear face and a front face to which a solid-state lighting device is secured in good thermal contact therewith, the light fitting comprising a fire resistant barrier and a heat sink mounted at a position at which it is exposed to the occurrence of a fire in the space for which the light fitting provide illumination.

24. A light fitting according to claim 23 wherein the heat sink is provided at said side of the fire resistant barrier that serves as the primary means for dissipation of heat from the solid-state lighting device.