GB2294752A - Lighting unit - Google Patents

Abstract

A lighting unit for underfloor lighting comprises a sealed housing closed by one or more reinforced glass brick(s) 10 and containing light emitting means such as an array of small lights or a single light bulb. Power supply components are also housed in the housing so that the unit can be fed directly from the mains. <IMAGE>

Description

LIGHTING UNIT The present invention relates to lighting units and it is a particular aim of the invention to provide a lighting unit which is suitable for outdoor use, especially at floor level.

Traditionally, walkways etc. are usually illuminated at night by overhead lamps but there are instances where under floor lighting would be useful, for example from aesthetic considerations or where installation of street lamps is not practical. Usually under-floor lighting has to be custom made. It would therefore be advantageous to provide an underfloor lighting unit which could be readily installed and used for a variety of applications.

The present invention provides a lighting unit including a housing closed by a reinforced transparent member which is sealed with respect to the housing to form a moisture-proof enclosure, and light emitting means housed inside the housing.

The lighting unit of the invention preferably uses, as the transparent member, a glass "brick" of the type which is available for letting daylight into basements from pavement level, for example. No system is currently available, as far as the present inventor is aware, which uses these "bricks" to provide artificial light.

A lighting unit according to the invention may include a single transparent member or an array of several such members. In the case of a single member, this may act as the closure of the housing. In the case of an array of transparent members, these may be supported in a frame which forms a lid for the housing.

Other preferred and advantageous features of the invention are described in the accompanying claims.

An embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of a first embodiment of lighting unit according to the invention; Figure 2 is a perspective view corresponding to Figure 1, showing the components assembled; Figure 3 is an exploded perspective view of a second embodiment of lighting unit according to the invention; Figure 4 is a perspective view showing some of the components of Figure 3, assembled, including a single light emitting means in the form of a light bulb; Figure 5 is a perspective view corresponding to Figure 4 showing only the light bulb and its supporting tray; and Figure 6 is a perspective view of the supporting tray from below showing additional components supported by the tray.

The lighting unit of Figure 1 comprises a four-way reinforced glass brick 10 of the type commonly used in pavements, for example to allow light into underground basements. The glass brick is installed in a housing 11 which houses a number of lamps, some of which are indicated by reference numeral 12. The lamps are mounted on a circuit board 13.

The housing 11 is square and comprises two sections, the upper square section lla having a larger area than the lower section llb so as to define a square shelf 15 on which the glass brick 10 rests.

The upper section lla is closed by the glass brick itself in a manner to be described below and the lower section llb is closed by an integral square planar cover 16.

The circuit board 13 which supports the lamps is mounted in the lower section llb at a distance below the glass brick 10 so that it is substantially parallel to the planar cover 16 of the housing 11 and the glass brick 10.

Between the circuit board 13 and the cover 16 are housed the components for supplying power to the lamps 12.

These will typically include a transformer transforming mains power fed into the housing 11 via a cable passing through the outlet 17 in the housing.

The glass brick 10 together with the housing 11 together form a sealed enclosure which prevents the ingress of dirt and moisture which could damage the lamps and electrical components inside the housing. To this end, a specially moulded seal 20 is provided between the glass brick 10 and the housing 11. As shown most clearly in figure 1 the seal forms the shape of a square and is Lshaped in cross section so that when the glass brick 10 is positioned horizontally, the seal 20 has a portion extending around the sides of the brick 10 and a portion extending underneath the brick which rests on the square shelf 15 in the assembled configuration.

A sealed cable gland is provided to lead a cable into the housing 11 via inlet 17, not shown in Figure 1.

The cable gland likewise prevents the ingress of dirt and moisture to the housing 11.

The lamps 12 may be fluorescent lamps each comprising a glass envelope filled with halogen gas from which the terminals of a tungsten filament, encased in the envelope, extend. This is just one example of the type of lighting arrangement which might be provided within the housing 11.

The housing 11 is preferably made of cast aluminium.

The embodiment of the invention shown in Figure 3 is an enlarged version of the lighting unit of Figures 1 and 2 including four glass bricks. Like parts in Figures 1, 2 and 3 are indicated with like reference numerals.

The lighting unit of Figure 3 includes four glass bricks 10. The glass bricks are mounted in a frame 30 which is divided into four sections and is constructed to form four square shelves, (not visible in Figure 3) similar to the square shelf 15 of Figure 1. The glass bricks 10 are secured in the frame and seated on the shelves to form a sealed cover, by means of seals 20. The frame 30 also provides a square outer flange 31 whose function will be described below.

The lighting unit further comprises a square open topped housing 32 which is closed by the assembly of frame 30, glass bricks 10 and seals 20. The housing 32 is preferably made from cast aluminium. The housing 32 includes a flange 33 extending beyond its side walls which is sized to cooperate with the flange 31 of frame 30. The housing 32 is provided with a liner 34, preferably made from stainless steel, which lines the walls of the housing 32 and provides extra protection for components located in the housing. The liner 34 also includes a flange 35 extending beyond its sidewalls.

It will be noted that the housing 32 has additional flanges 39 extending along opposite parallel edges of its lower surface which are substantially coextensive with flange 33 of housing 32 and flange 35 of liner 34. The illustrated lighting units can be assembled into continuous arrays and the flanges 39 facilitate the abutment of units against each other to form an array.

Flanges could be provided along all four edges of the housing 32.

In the assembled configuration, the liner 34 is positioned inside the housing 32 so that flange 35 rests on flange 33. The housing is closed by the cover comprising the glass bricks 10 mounted in their frame 30. The flange 31 of the frame 30 is sized to cover the flange 35 of the liner 34. Between the flange 31 of the frame 30 and the flange 35 of the frame 34 is positioned a waterproof seal 37 which may be made of rubber for example. The waterproof seal 30 is made from flat sheet material cut in the shape of a square having a square central opening so that it is substantially co-extensive with the flanges 31 and 35.

The housing 32 has tapped holes 40 at the corners of the flange 33 and midway along the side portions of flange 33 to receive tamper-proof screws which pass through aligned holes in the flange 31 seal 37 and flange 35. These screws can only be removed with the use of special tools.

The housing may house a large array of lamps of the type shown in Figure 1 or any other suitable lighting means. One alternative example is shown in Figures 4, 5 and 6.

Figure 4 shows the assembled components of Figure 3 with the frame 30 and seal 37 removed to reveal a light bulb 50 supported on a tray 51. The housing is viewed from the opposite side in Figure 4 to that shown in Figure 3, to additionally reveal a sealed cable gland 52 via which a cable supplying power (eg. mains) may be led into housing 32, at the same time preventing ingress of dirt and moisture. Cable glands of this type are commonly available and will not be described in detail herein.

The tray 51 is shown in more detail in Figures 5 and 6 and comprises a square sheet having upstanding side walls 51a extending along opposite edges perpendicular to the plane of the sheet and flanges 51b extending from the edges of the side walls remote from the sheet, parallel to the plane of the sheet. The tray 51 fits snugly into the liner 34 with the flanges Slb resting on the base of the liner. The light bulb 50 is mounted on the liner via an Lshaped bracket 53 which is bolted to the tray.

On the underside of the tray 51 are mounted components for supplying power to the light bulb 50 including capacitor 54, starter 55, and ballast component 56 which controls the supply of power. These are likewise mounted to the tray by respective L-shaped brackets 57, 58 and 59. The tray is provided with a hole or recess via which wires pass from the components on the underside of the tray to the light bulb 50.

The light bulb 50 may of course comprise a fluorescent or incandescent bulb. In contrast to existing lighting systems, all of the necessary control gear is provided inside the housing.

The lighting unit shown in Figures 3 to 6 is particularly easy to maintain since the screws can simply be removed to release the lid without the need to remove the unit from its installation.

The housing is made sufficiently strong to resist all loads to which it might be subjected, including being driven over by vehicles.

The housing is preferably square but it could be rectangular, hexagonal, or any other shape which permits the formation of a continuous array without gaps. Referring to Figure 3, suitable dimensions for the "four brick" version are side length x = 373mm, housing depth y = 160mm and total assembled depth z = 175mm.

It should be noted that a row of housings 32 could be modified to accommodate a typical elongate fluorescent tube, by providing sealed holes in the side walls in appropriate places.

Claims (11)

CLAIMS:

1. A lighting unit including a housing closed by a reinforced transparent member which is sealed with respect to the housing to form a moisture-proof enclosure, and light emitting means housed inside the housing.

2. A lighting unit as claimed in claim 1 including sealing means positioned between the transparent member and the housing.

3. A lighting unit as claimed in claim 1 or 2 in which the housing defines a shelf on which the transparent member is supported.

4. A lighting unit as claimed in claim 3 in which the sealing means extends around the transparent member and is L-shaped in cross section, to include a portion resting on the shelf in use and a portion abutting against the edges of the transparent member.

5. A lighting unit as claimed in claim 3 or 4 in which the housing includes a lid which defines one or more of said shelves for supporting one or more transparent members.

6. A lighting unit as claimed in claim 5 including a seal positioned between the lid and the remainder of the housing.

7. A lighting unit as claimed in any preceding claim in which the transparent member is made from reinforced glass.

8. A lighting unit as claimed in any preceding claim in which the surface bearing the or each transparent member has a shape capable of forming a continuous array.

9. A lighting unit as claimed in any preceding claim in which the housing also houses electrical components for controlling the supply of power to the light emitting means.

10. A lighting unit as claimed in any preceding claim in which the or each light emitting means is mounted on a board supported inside the housing.

11. A lighting unit substantially as hereinbefore described with reference to the accompanying drawings.