Description: This invention relates to luminaires, and in particular, but without limitation, to improvements in and relating to flush-mounting luminaires, or downlighters.

Flush-fitting luminaires are used in many modern lighting applications because they provide an aesthetically pleasing lighting effect even though the luminaire itself is mostly hidden from view. Flush-fitting luminaires generally comprise a main body portion that can be recessed into a wall, ceiling or other surface. The main body portion is usually designed to fit inside a generally cylindrical envelope, thus conveniently enabling the light fitting to be inserted into a circular, drilled or cut hole in the mounting surface. The luminaire is thus mainly contained within a plenum behind the wall, floor or ceiling, and this enables wiring etc. leading to the luminaire to be conveniently concealed from view.

A peripheral lip is usually provided on the main body portion for limiting the extent of insertion of the main body into the surface and to conceal the intersection of the periphery of the hole in the mounting surface and the outer edge of the main body portion.

Likewise, to retain the luminaire in position, a retainer is typically employed, which cooperates between the main body portion and the rear surface of the wall, floor or ceiling surface inside the plenum. The retainer can take the form of a set of sprung clips, which urge the peripheral lip into engagement with the front surface of the wall, floor or ceiling.

In many cases, a cowl, fascia, lens, diffuser or other decorative or functional element is mounted to the peripheral lip to complete the assembly, thus providing an aesthetically pleasing result, once installed.

In modern flush-fitting luminaires, the light source comprises one or more LEDs that are powered by mains electricity, usually via a driver circuit. The LED or LEDs can be formed integrally with the main body portion of the light fitting, or they can take the form of a removable lamp, which engages a corresponding socket of the luminaire. Alternatively, the socket can be of a standardised type (e.g. an Edison screw, bayonet, MR16, GU10, etc. type fitting) which enables the luminaire to be used in conjunction with a range of compact fluorescent, filament or halogen lamps.

Flush-fitting luminaires are available in a range of shapes, sizes and configurations to suit different applications, and some flush-fitting luminaires comprise tiltable lamp assemblies to enable the direction of the emitted light beam to be adjusted, for example, to create a "wall wash" or "directional spot" lighting effect, depending on the lamp configuration.

Whilst known flush-fitting luminaires meet many of the requirements for lighting installations, they do, however, suffer from a number of drawbacks.

In known, tiltable, flush-fitting luminaires, the tilt angle tends to be limited by the size constraints of the main body portion. The limits of the tilt angle are imposed by factors such as: the need for the main body portion of the luminaire to be compact so that it fits inside the aforementioned cylindrical envelope for insertion and removal purposes; and the set-back distance of the light source from the front of the luminaire, which affects the maximum beam angle of the luminaire.

A further drawback of known flush-fitting luminaires is that they can usually only be installed into surfaces where the material thickness is of a specified dimension. This limitation arises due to the nature of the retaining spring clips, which only work effectively through a limited range of angles: if the ceiling board thickness is too thin, the spring clips engage weakly leading to the luminaire fitting loosely in its hole; or if the ceiling board thickness is too thick, the spring clips will be over-stretched, often beyond their elastic limit, also leading to a wobbly installation. This problem is particularly acute where a flush-fitting luminaire is to be installed in a double-boarded ceiling, such that the thickness of the plasterboard can be two or more times the thickness of a single-boarded ceiling. A similar situation arises where a flush-fitting luminaire needs to be installed in a relatively thin, e.g. a plywood surface, which is considerably thinner than the thickness of a conventional sheet of plasterboard: the spring clips in this situation can often be ineffective at securely retaining the luminaire in positon. A need therefore exists for a new and/or improved luminaire, which addresses or overcomes one or more of the above problems, and/or which provides an alternative to known luminaires.

Various aspects of the invention are set forth in the appendent claims.

According to a first aspect of the invention, there is provided a luminaire comprising a main body portion and a illumination source portion articulably connected to one another, the main body portion comprising: a peripheral wall receivable, in use, in an aperture of a mounting surface and defining an opening of the luminaire through which, in use, a light source of the illumination source portion can shine; a peripheral lip configured, in use, to abut a front surface of the mounting surface to inhibit insertion of the main body portion into the aperture beyond a given point; and retaining means cooperating between the main body portion and a rear surface of the mounting surface to secure the main body in the aperture of the mounting surface, wherein the main body portion and the illumination source portion are articulably connected to one another via a pivot whose axis is laterally offset from the midline of the opening of the peripheral wall.

By offsetting the axis of the pivot from the midline of the opening of the peripheral wall, the illumination portion can be pivoted, and thus follow an arcuate locus centred on the laterally offset pivot axis. Such a configuration enables the illumination source, during movement relative to the main body portion, to tilt and move vertically towards, or away from, the opening in the luminaire. Suitably, such a configuration may usefully enable the illumination portion to be moveable through a greater range of angles than known luminaires whose pivot axes are generally centred on the opening.

Further, by moving the illumination source portion towards, closer to, and or into or through the opening as the tilt angle of the illumination source is increased, the peripheral wall of the main body portion is less likely to obscure part of the beam of the light source.

Suitably, an arcuate limb interconnects the main body portion and the illumination source portion. Suitably, the arcuate limb comprises a first end rigidly connected to the illumination source portion and a second end, which is pivotally connected to the peripheral wall of the main body portion. The provision of an arcuate limb may avoid fouling of the illumination source portion with the main body portion as it moves through is range of movement.

According to a second aspect of the invention, there is provided a luminaire comprising a main body portion and a illumination source portion, the main body portion comprising: a peripheral wall receivable, in use, in an aperture of a mounting surface and defining an opening of the luminaire through which, in use, a light source of the illumination source portion can shine; a peripheral lip configured, in use, to abut a front surface of the mounting surface to inhibit insertion of the main body portion into the aperture beyond a given point; and retaining means cooperating between the main body portion and a rear surface of the mounting surface to secure the main body in the aperture of the mounting surface, wherein the retaining means comprises a screw threaded axle mounted for rotation about an axis substantially perpendicular to the peripheral lip and a limb adapted, in use to engage the rear surface of the mounting surface, the limb being screw-threaded connected to the screw threaded axle, such that rotation of the screw threaded axle about its axis causes the limb to move parallel to the said axis to cause the limb to engage with the rear surface of the mounting surface.

Suitably, an end of the screw threaded axle is accessible via an aperture in the peripheral lip. Suitably, an end of the screw threaded axle comprises engagement means (such as a screwdriver slot, an Allen key fitting or the like) to enable the screw threaded axle to be rotated using a suitable tool.

Suitably, the limb has a generally cranked, S-shaped or Z-shaped form and can be detached from the screw threaded axle and reattached in an opposite orientation. Such a configuration conveniently enables the limb to accommodate a greater range of mounting surface thicknesses, for example, a first range of mounting surface thicknesses with the limb connected to the screw threaded axle in a first orientation, and a second range of mounting surface thicknesses with the limb connected to the screw threaded axle in a second orientation. Suitably, the first and second ranges overlap. Thus permitting the limb to be used over an entire range of mounting surface thicknesses determined by the limits of the first and second ranges. The main body portion can be manufactured from metal, e.g. cast aluminium, pressed steel, or in certain embodiments, the main body portion may be manufactured from injection moulded plastics. Injection moulded plastics may permit a range of aesthetically pleasing surface finishes and/or colours to be obtained, they may be lighter weight than metal counterparts, and in, for example, outdoor installation applications, they may be less susceptible to corrosion.

The main body portion suitably comprises a circular, annular or round peripheral wall, as this facilitates installation of the luminaire: a hole can be simply drilled into the mounting surface of a suitable size and the luminaire inserted into the drilled hole. This need not, however, be the case: the main body portion may take other overall forms, such as a square or rectangular form, depending on the requirements of the installation.

The illumination source portion suitably comprises a light source, such as one or more LEDs, and a driver for the LED or LEDs. Suitably, the LED driver and the LEDs are formed as a unit, which forms part of the illumination source portion.

In alternative embodiments of the invention, the illumination source portion comprises a socket for receiving a lamp. The socket can be of any suitable type, such as an Edison screw fitting, a bayonet fitting, an M 16 fitting, a GU10 fitting, etc. Such a configuration enables the lamp (light source) to be replaced at intervals and/or the light beam pattern to be adjusted by the selection of different types of lamps.

The luminaire suitably comprises a fascia, which sits over or around the opening in the peripheral lip or wall of the main body portion. Conveniently, the fascia attaches to the peripheral lip or wall by releasable securing means, such a clip fitting, or a magnet. The fascia can comprise decorative and/or functional elements, such as a diffuser, a filter (e.g. for changing the colour of the emitted light beam or blocking certain wavelengths), a lens (e.g. for focussing or spreading the light beam), etc.

The retaining means may comprise a spring clip, or, in preferred embodiments of the invention, the retaining means according to the second aspect of the invention. Preferred embodiments of the invention shall now be described, by way of example only, with reference to the accompanying drawings in which:

Figures 1 and 2 are schematic cross-sectional views of a known flush-fitting luminaire in an upright and tilted configuration, respectively;

Figures 3 and 4 are equivalent schematic cross-sectional views to those shown in Figures 1 and 2 of a flush-fitting luminaire in accordance with the invention in an upright and tilted configuration, respectively;

Figures 5 is a schematic overlay view comparing the luminaires of Figures 2 and 4;

Figure 6 is a perspective view of a flush-fitting luminaire in accordance with the invention; and Figure 7 is a perspective view of the luminaire of Figure 6 with its retaining means in an opposite orientation to that shown in Figure 6.

Referring now to Figures 1 and 2 of the drawings, a known flush-fitting luminaire 10 is shown, which comprises a main body portion 12 and an illumination source portion 14 that are pivotally connected to one another. The illumination source portion 14 is connected to the main body portion 12 by an arcuate support 16 carrying an axle (not shown) about whose axis 18 the illumination source portion 14 is free to pivot.

The main body portion 12 comprises a peripheral wall 20 that is slidingly receivable in a correspondingly shaped and sized aperture 22 of a mounting surface 24 (e.g. a plasterboard ceiling). A peripheral lip portion 26 of the peripheral wall 20 abuts the front surface 28 of the mounting surface 24, thus inhibiting the insertion of the main body portion 12 into a plenum space 30 behind the mounting surface 24 beyond a desired extent. A pair of spring clips 32 connected to the peripheral wall 20, bear against the rear surface 34 of the mounting surface 24, thus inhibiting removal of the luminaire 10, once installed.

The illumination source portion 14 comprises a light source 36, such as an LED or a lamp, which emits a beam of light 38 through an opening 40 defined by the peripheral wall 20. The beam 38 angle is determined by the optics of the lamp 36, but is can be seen that the beam angle is selected to "fit" though the opening 40.

The pivot axis 18 is centred on the opening 40 and when the illumination source portion 14 is upright (as shown in Figure 1) the beam 38 shines unobstructed through the opening 40.

However, as shown in Figure 2, when the illumination source portion 14 is tilted about the pivot axis 18, the edge of the beam 38 impinges on the peripheral wall 20 of the main body portion 12, which casts a shadow 42, thus partially obscuring the light beam 38. This has two potentially adverse effects: first, it reduces the light output of the luminaire 10 because some of the beam 38 is blocked by the light fitting 10; and second, because a portion of the beam 38 is incident on the peripheral wall 20 at close range (typically l-3cm), this can cause the peripheral wall 20 to become hot, which is generally undesirable.

Turning now to Figures 3 and 4 of the drawings, a flush-fitting luminaire 100 in accordance with the invention is shown. For the avoidance of repetition, identical features appearing in Figures 3 to 7 of the drawings to those appearing in Figures 1 and 2 and which have already been described, are identified with identical reference signs, for ease of understanding and comparison purposes.

In Figures 3 and 4 of the drawings, it can be seen that the illumination source portion 14 of the luminaire 100 is connected to the main body portion 12 via a rigid, arcuate limb 102, that pivots about a pivot axis 18 that is located above the peripheral wall 20 of the main body portion 12 (as opposed to being centred on the opening 40, as described above in relation to Figures 1 and 2).

As can be seen by comparing Figures 3 and 4, when the illumination portion 14 is tilted relative to the main body portion 12, the light source 36 follows an arcuate locus 104 moving slightly to the right (in the drawing) and down towards into the opening. By moving the light source 36 along this arcuate locus 104, it can be seen that the beam 38 is no longer obscured by the peripheral wall 20 of the main body portion 12 as it was in the known luminaire 10 shown in Figures 1 and 2 of the drawings. This configuration thus overcomes one of the drawbacks of the known luminaire 10 inasmuch as the light beam 38 is no longer obscured by the peripheral wall 20; and thus, the peripheral wall is no longer heated by impinging light from the light source 36.

It can also be seen by comparing Figures 1 and 2 with Figures 3 and 4, that the retaining clip 32 has been replaced by a screw-actuated retaining means 106. The screw-actuated retaining means 106 comprises a threaded axle 108 that extends through the main body portion and which terminates at the lower edge of the peripheral lip 26. The end of the threaded axle 108 is provided with a screwd river slot 110, which enables the threaded axle 108 to be rotated 112. A cranked limb 114 having a screw-threaded through aperture (not shown) engages the threaded axle 108 and is thus displaced vertically 116 as the threaded axle 108 is rotated 112. This causes a free end of the cranked limb 114 to bear against the rear surface 34 of the mounting surface 24, thus retaining the luminaire 100 in position.

It can be seen, from the right hand side of Figure 4, that the cranked limb 114 can be taken off and re-engaged with the threaded axle 108 in an opposite orientation. This permits the luminaire 100 to be installed where the thickness of the mounting surface is thicker (e.g. in a double-boarded ceiling situation).

A comparison of Figures 2 and 4 is shown in Figure 5 of the drawings. From Figure 5 it can be appreciated that for otherwise identical optical configurations, the beam angle 120 of the luminaire 100 in accordance with the invention is considerably bigger than the beam angle 122 of the known luminaire 10. This results in a better light output in most situations.

Figures 6 and 7 are perspective views of a luminaire 100 in accordance with the invention, showing the physical configuration of the main body portion 12, the illumination source portion 13, the arcuate limb 102 and the laterally offset pivot axis 18.

Figures 6 and 7 also show in perspective, the configuration of the screw-actuated retaining means 106, complete with its cranked limb 114, which can be oriented in one of two orientations. The screw-actuated retaining means 106 comprises an upright support limb 130, which supports the upper end of the threaded axle 108. This serves two main purposes: first, to stabilise the threaded axle 108; and second, to provide an edge 132 against which a side of the limb 114 abuts when the threaded axle 108 is rotated 112. This configuration prevents the limb 114 from simply spinning around as the threaded axle 108 is rotated 112, thus forcing it to be displaced 116 vertically upon rotation 112 of the threaded axle 108; as well as ensuring that the limb 114 projects radially outwardly from the luminaire 100 to engage the rear surface 34 of the mounting surface 24.

The screwdriver slot 110 is also visible in Figures 6 and 7. This is concealed, in use, and after installation, by affixing any one of several possible fascias 140, 142, 144 to the peripheral lip 26 of the main body portion 12, e.g. using a magnet formed integrally with the main body portion 12 of the fascia 140, 142, 144.

In Figure 6, it can be seen that a first type of fascia 140 comprises a decorative cowl 146; a second type of fascia 142 comprises a lens 148 (e.g. for focussing or spreading the light beam 39); and a third type of fascia 144 comprises a diffuser and/or a filter 150.

Finally, referring now to Figure 7 of the drawings, it can be seen that the range of movement

152 of the cranked limb 114 in a first orientation overlaps the range of movement 154 of the cranked limb 114 in the opposite orientation. This configuration usefully enables an installer to "guess" which orientation in which to use the cranked limb 114, as well as providing a much greater, and continuous range of movement, i.e. as defined by the lower limit 156 of the first range of movement 152 and the upper limit 158 of the second range of movement 154.

The foregoing embodiments are exemplary and it will be appreciated that alternative shapes, sized, materials, dimensions and configurations can be used without departing from the scope of the invention, which is defined by the appendent claims.