GB2517222A

GB2517222A - A light fitting

Info

Publication number: GB2517222A
Application number: GB1318851.1A
Authority: GB
Inventors: Simon Cadisch
Original assignee: Ecoled Ltd
Current assignee: Ecoled Ltd
Priority date: 2013-10-25
Filing date: 2013-10-25
Publication date: 2015-02-18
Anticipated expiration: 2033-10-25
Also published as: GB201318851D0; GB2521962B; GB2517222B; GB201506712D0; HK1211336A1; GB2521962A

Abstract

A light fitting for recessed mounting of a luminaire 100 on a substrate comprises a base 20 having a longitudinal axis X-X, a luminaire support 30, and an adjustable coupling mechanism to adjust the position of the luminaire support 30 in relation to the base 20 along the longitudinal axis. The adjustable coupling mechanism is operable by way of manipulation of the luminaire support 30 to couple or decouple the luminaire support from the base 20. The adjustable coupling mechanism comprises a tooth arrangement 60-66 on the luminaire support 30 engageable with a tooth engagement means 52a-52e on the base 20. The adjustable coupling mechanism enables the luminaire support 30 to occupy at least two different positions along the longitudinal axis X-X of the base 20.

Description

A Light Fitting The present invention relates to a light fitting for recessed mounting of a luminaire in a substrate.

Lights recessed within walls or ceilings have been popular for some time. The display industry, in particular in department stores, has used recessed light fittings for some time. A single light fitting may be used to light a general overall area or it may be used to direct light at a particular object.

Patent publication US3,660,651 discloses a light fitting for recessed mounting of a luminaire comprising a filament lamp in ceiling tiles, like the recessed light fittings found in a department store or other commercial environments. The luminaire may be pivoted to direct light at various angles and it may be moved in a vertical direction between a position recessed in the light fitting and a position extending from the light fitting. This enables adjustment between lighting a general area, or a particular object, at various angles or light intensities.

Recessed light fittings have become popular in other situations, like, for example, the domestic environment. This popularity has gathered pace with advances in technology that have resulted in light-emitting diodes becoming a viable alternative light source to filament lamps. For the sake of brevity, the conventional term "LED" shall be used to describe a light-emitting diode hereon. The popularity of recessed light fittings is complemented by a need for economic installment techniques. Whilst the recessed light fitting of US3,660,651 may have an adjustable light output, it comes as an assembled unit of multiple parts including the luminaire which are enclosed within a housing. The installer must mount the whole light fitting in a recess at the same time. This makes heavy work for the installer. The same applies to removal of the light fitting for maintenance, or repair, which must be done on the whole unit. The installment of the light fitting of US3,660,651 is an inflexible process which takes time and effort.

It is an object of the present invention to provide an improved light fitting.

Accordingly, in a first aspect of the present invention, there is provided a light fitting for recessed mounting of a luminaire in a substrate, the light fitting comprising: a base having a longitudinal axis; a luminaire support; and an adjustable coupling mechanism operable to adjust the position of the luminaire support in relation to the base along both directions of the longitudinal axis of the base and wherein the adjustable coupling mechanism is operable by way of manipulation of the luminaire support to couple or decouple the luminaire support from the base. The light fitting of the present invention has an adjustable coupling mechanism that may extend, or retract, the luminaire support in relation to the substrate in which the light fitting is mounted. Advantageously, manipulation of the luminaire support can also be used to couple, or decouple, the luminaire support from the base. This enables the base to be connected to the substrate, like, for example, a wall or ceiling, without the luminaire support. This reduces the weight of the installation task because only the base may be installed initially. The luminaire support may be coupled, possibly tool-free, to the base later. For example, a batch of bases may be installed and then the luminaire supports are coupled to the bases later when the electrical power supplies are ready for connection. Alternatively, a luminaire support, equipped with luminaire, may be decoupled and repaired or replaced while the base remains undisturbed. The installer can manipulate the electrical power supply and connect it to a freestanding luminaire in the luminaire support before the latter is re-coupled to the base.

Luminaire supports, each with LED luminaire, may be retro4itted in place of filament lamps, again without disturbing the base. These are some examples of how the present invention provides a more flexible and cost effective light fitting.

Preferably, the coupling mechanism is operable by way of manipulation of the luminaire support to adjust the position of the luminaire support in relation to the base along both directions of the longitudinal axis of the base. This may simplify use and installation of the light fitting by relying on manipulation of only one component to operate the coupling mechanism.

Preferably, the locking mechanism is operable by rotation of the luminaire support in relation to the base. This is a simple and intuitive means of operation.

Preferably, the position of the luminaire support in relation to the longitudinal axis of the base is adjustable in increments. Adjustment movement may follow, for example, a straight line, a helical path, or a zig-zag path. Adjustment in increments provides the installer with tactile feedback which is helpful if visibility is impaired.

The base may comprise a collar configured for recessed mounting in a substrate.

The collar may provide a protective wall between the substrate and components of the light fitting.

Preferably, the collar comprises a hollow cylinder and the luminaire support is configured to telescope within the collar. This may provide reliable guided linear movement between collar and luminaire support.

Preferably, the base has an outer end and an inner end at an opposite longitudinal end of the base to the outer end and wherein luminaire support is adjustable between an extended position substantially at the outer end and a retracted position distal from the outer end. The extended position may provide full light output from a luminaire in the light fitting. The retracted position may be desirable to reduce glare from the luminaire in certain locations, like, for example, near a curtain or a picture in a domestic environment. The ability to conceal the light source to a varying degree is an attractive option. The installer need install only one type of light fitting in different locations about an office, or a home, and yet still be able to adjust light intensity according to individual tastes. The customer may adjust light intensity without need to rely on the original installer.

Preferably, the outer end of the base comprises an outer flange configured for engagement with a substrate. This helps to prevent the base receding too far within a hole in a substrate. The outer flange may have an array of perforations. The outer flange may be plastered over to help conceal all but light from the light fitting. The perforations help adhesion of the plaster to the outer flange and help key the base into the substrate.

The light fitting may comprises a luminaire connected to the luminaire support.

Thus, the light fitting is ready for connection to an electrical power supply and use.

Preferably, the luminaire is pivotal in relation to the luminaire support about the longitudinal axis of the base. This enables the angled orientation of light from the light fitting to suit certain locations. The luminaire may be releasably connected to the luminaire support. This facilitates replacement and repair of the luminaire and retro-fitting of a different type of luminaire. Alternatively, the luminaire support may integral with the luminaire. This reduces components and may reduce manufacturing costs which could be passed on to the customer.

Preferably, the coupling mechanism comprises: a tooth arrangement on one of the base or the luminaire support; and a tooth engagement arrangement on the other of the base or the luminaire support, wherein the tooth arrangement is engagable with the tooth engagement arrangement to couple the luminaire support in at least two different positions in relation to the longitudinal axis of the base and wherein the tooth arrangement is disengagable from the tooth engagement arrangement to decouple the luminaire support from the base. This provides a simple and reliable engagement system which is easy to manufacture.

The tooth arrangement may comprise at least one set of a plurality of teeth and wherein each tooth is offset from the next consecutive tooth of the same set in the direction of the longitudinal axis of the base. Each tooth represents a different position of the luminaire support in relation to the longitudinal axis of the base. Preferably, each tooth is offset from the next consecutive tooth of the same set in a direction of rotation about the longitudinal axis of the base. This enables, for example, helical movement (which is preferred) or zig-zag movement, of the luminaire support as it moves between different positions in relation to the base.

The tooth arrangement may comprise a plurality of sets of teeth. Preferably, the sets of teeth are arranged at equiangular intervals about the longitudinal axis of the base.

This may help to spread engagement between teeth and the tooth engagement means evenly about the longitudinal axis.

Preferably, the tooth engagement arrangement comprises a shelf for the or each set of teeth. The teeth may rest up the shelf which provides a simple and easily manufactured support.

Preferably, the or each shelf comprises a respective portion for retaining a tooth.

The retaining portion is somewhere to reliably park, or hold, the tooth and provide tactile feedback to someone operating the coupling mechanism. Preferably, the or each shelf comprises a respective ramp. The ramp may help guide the tooth arrangement between the two or more positions the luminaire support may adopt in relation the base. A ramp may be easily manufactured. Preferably, the or each shelf comprises a respective stop.

The stop may assist one-handed operation of the coupling mechanism by providing an indication that a desired position has been reached.

Preferably, the coupling mechanism is operable by rotation of the luminaire support in relation to the base about a substantially helical path. Operation along a helical path does not require much torque and so the lurninaire support may be turned with fingertips, for example. If the helical path is less than one revolution then it may allow adjustment of the position of the luminaire support without significantly twisting electrical power supply cables connected to a luminaire. Preferably, the or each portion for retaining a tooth is located outside the substantially helical path. Departure from the helical path may provide the installer with tactile feedback as to when a position of the luminaire support has been selected and reached.

The base may comprise the tooth engagement assembly and the luminaire support comprises the tooth assembly.

Preferably, the adjustable coupling mechanism is operable by way of manual grip of the luminaire support optionally facilitated by finger grip on the luminaire support or operable by way of manipulation with a special tool optionally including magnetic connection to the luminaire support.

In a second aspect of the present invention, there is provided a base having a longitudinal axis, wherein the base is configured to be coupled to the luminaire support of the light fitting of the first aspect of the present invention. The base may be sold separately to enable to replacement or repair the original base and to avoid discarding the other components of the light fitting unnecessarily.

In a third aspect of the present invention, there is provided a luminaire support configured to be coupled to the base having a longitudinal axis of the light fitting of the first aspect of the present invention. The luminaire support may be sold separately to enable to replacement or repair the original luminaire support and to avoid discarding the other components of the light fitting unnecessarily.

These and other features and advantages of the present invention wifl be better understood from the foflowing detafled descriptior., which is given by way of exampe and with reference to the accompanying drawings, in which: Figure 1 shows a cross-sectional view of a light fitting mounted in a recess in a substrate; Figure 2 shows an exploded perspective view of the ight fitting of Figure 1; Figure 3 shows a perspective view trom above the light fitting of Figure 1 in a retracted position; Figure 4 shows a perspective view from below the light fitting of Figure 1 in the retracted position; Figure 5 shows a perspective view from above the light fitting of Figure 1 in an extended position; Figure 6 shows a perspective view from above a base of the light fitting of Figure 1; and Figure 7 shoes a perspective view from above a uminaire collar support of the light fitting of Figure 1; Figure 8 shows a perspective view from above the uminaire collar support engaged with the base; Figure 9 shows a schematic diagram of an innermost tooth of the uminaire support rotating in relation to the base; Figure 10 shows a schematic diagram of an inner tooth of the uminaire support rotating in relation to the base; Figure 11 shows a schematic diagram of an outer tooth of the luminaire support rotating in relation to the base; and Figure 12 shows a schematic diagram of an outermost tooth of the luminaire support rotating in relation to the base.

Referring to figures 1 to 8, there is shown a light fitting 10 for recessed mounting of a luminaire 100 in a substrate S. The substrate S shown in figure 1 may be, for example, a plasterboard wall or ceiling, or ceiling tile, that is a facade to a cavity C large enough to accommodate the light fitting 10, the luminaire 100 and its associated electrical power supply cables (not shown). Alternatively, the substrate S may be, for example, a solid wall formed with a recess to accommodate the light fitting 10 and the luminaire 100 and provide a conduit for its electrical power supply cables. The light fitting typically mounts a luminaire having an external diameter of about 55mm to 75mm but its simple design makes it suitable for mounting a luminaire having a much smaller, or bigger, external diameter.

The light fitting 10 comprises a trimless collar in the form of a base 20 for connection to the substrate S and a luminaire support 30 for supporting a luminaire 100.

The luminaire support 30 is adjustably coupled to the base 20 by an adjustable coupling mechanism as is described in more detail below. The adjustable coupling mechanism may couple and decouple the luminaire support 30 from the base 20 by manipulation of the luminaire support 30 as is also described in more detail below.

The base 20 comprises a hollow cylindrical collar 22 having a central longitudinal axis X-X and a wide annular outer flange 24 arranged about an outer end 22a of the base collar 22 in a plane P orthogonal to the longitudinal axis X-X. The base 20 further comprises an annular inner flange 26 arranged inside an inner end 22b of the base collar 22 opposite to the outer end 22a of the base collar 22. The base collar 22, the outer flange 24 and the inner flange 26 of the base 20 are made as one integral part, although, optionally, they may be made of separate parts and assembled together to form the base 20. The base 20 may be made of any suitable material, provided it is fire retardant, like for example, metal, ceramic, plastic, fibre glass or composite material.

The outer flange 24 has an array of perforations 28 of various shapes and sizes.

When the light fitting 10 is mounted in a recess of a substrate 5, the outer flange 24 is relatively thin and it may be plastered over to conceal the base 20 within the substrate S. The perforations 28 help to key the outer flange 24 into the layer of plaster to improve connection of the light fitting lOto the substrate S. The inner flange 26 has a profiled inner surface comprising three lobes 50a-50c arranged at equiangular intervals of angle a of 120 degrees about the longitudinal axis X-X. The lobes 50a-50c protrude radially inwardly a small distance (about 3mm or 4mm) from the inner cylindrical face 23. Located between the lobe 50a and the lobe 50b, the inner flange 26 comprises consecutively, in a direction of anti-clockwise rotation R' as viewed from the inner end 22b of the collar 22, a recess 52a adjacent the lobe 50a, a ramp 54a, a raised step 56a and a parking step 58a adjacent the lobe SOb. Further, located between the lobe 50b and the lobe 50c, the inner flange 26 comprises consecutively, in the direction of anti-clockwise rotation R', a recess 52b adjacent the lobe 50b, a ramp 54b, a raised step 56b and a parking step 58b adjacent the lobe 50b. Furthermore, located between the lobe SOc and the lobe 50a, the inner flange 26 comprises consecutively, in the direction of anti-clockwise rotation R', a recess 52c adjacent the lobe 50c, a ramp 54c, a raised step 56c and a parking step 58c adjacent the lobe 50a.

The midpoints of the recess 52a, the ramp 54a, the raised step 56a and the parking step 58a are arranged at consecutive equiangular intervals of angle 13 of approximately 30 degrees in the anti-clockwise direction R'. Further, the midpoints of the recess 52b, the ramp 54b, the raised step 56b and the parking step 58b are arranged at consecutive equiangular intervals of approximately 30 degrees (angle 13) in the anti-clockwise direction R'. Furthermore, the midpoints of the recess 52b, the ramp 54b, the raised step 56b and the parking step 58b are arranged at consecutive equiangular intervals of approximately degrees (angle 13) in the anti-clockwise direction R'.

Like the lobes 50a-50c, the recesses 52a-52c are arranged at equiangular intervals of 120 degrees in relation to each other as are the ramps 54a-54c, the raised step 56a-56c and the parking step 58a-58c.

The luminaire support 30 comprises a hollow cylindrical collar 32 having the central longitudinal axis X-X, an annular external channel 34 and an annular internal channel 35 each arranged at an outer end 32a of the collar 32. The external channel 34 supports an external 0-ring 34a and the internal channel 35 supports an internal 0-ring 35a. The cylindrical collar 32 has an annular inner flange 36 arranged inside the collar 32 substantially half-way between the outer end 32a and an inner end 32b of the collar 22 opposite to the outer end 32a. The support collar 32 has an annular internal groove 38 arranged between the inner flange 36 and the inner end 32b of the collar 22.

The support collar 32 has three sets of four teeth protruding from an outer cylindrical face 33. Each set of teeth comprises an outermost tooth 60 nearest the support external channel 34 and, in order of distance from the support external channel 34 in the direction of the longitudinal axis X-X, an outer tooth 62, an inner tooth 64 and an innermost tooth 66 nearest the inner end 32b of the support collar 32. Each set of teeth is arranged along a substantially helical path HP beginning at the outermost tooth 60 and following consecutively, in the direction of anti-clockwise rotation R', with the outer tooth 62, the inner tooth 64 and the innermost tooth 66 at the inner end 32b of the support collar 32.

The midpoints of consecutive teeth are spaced apart in equiangular intervals of 60 degrees (i.e. twice angle 13) about the longitudinal axis X-X. The helical path HP typically has a helix angle y of between about five and ten degrees, but this simple design of light fitting may facilitate smaller, or greater, helix angles. The external channel 34, the internal channel 35 and the inner flange 36 of the support collar 32 are made in one integral part, although, optionally, they may be made of separate parts and assembled together to form the support collar 32. The support collar 32 may be made of any suitable material, provided it has inherent resilience and it is fire retardant, like for example, metal, ceramic, plastic, fibre glass or composite material.

The luminaire support 30 further comprises a pivoting socket 44 and an annular trim 46. The pivoting socket 44 is seated inside the support collar 32 between the inner flange 36 and the internal groove 38. During assembly, the pivoting socket 44 is inserted in the support collar 32 from the inner end 32b until part 106 of the luminaire 100 snap-fits into the internal groove 38 and behind the pivoting socket 44 to secure it against the inner flange 36. The pivoting socket 44 may be removed from the support collar 32, but this requires reversal of the snap-fit engagement. The annular trim 46 is seated in the outer end of the pivoting socket 44 and connected thereto by, for example, adhesive or an interference fit. The annular trim 46 is mainly for decorative purposes and may, alternatively, be integral with the support collar 32 or the pivoting socket 44. Likewise, the pivoting socket 44 may, alternatively, be integral with the support collar 32.

The external 0-ring 34a excludes draft between the base 20 and the luminaire support 30 whilst at the same time permitting relative movement between the base 20 and the luminaire support 30. The internal 0-ring 35a excludes draft between pivoting socket 44 and the cylindrical collar 22.

The luminaire 100 has a casing 102, a heat sink 104, control electronics (not shown), an annular web 106 and optical elements 108 like, for example, a light source, a lens, a reflector, a diffusion medium and/or a filter to direct and shape light from the light source. The light source may be filament lamp or an LED, for example. The light source receives electrical current from an electrical power supply cable (not shown) leading into the cavity C. LEDs have a ower energy consumption, longer Ufespan and greater rehability than filament lamps which make LEDs a preferred option of light source.

An outer spherical head 102a of the casing 102 is surrounded by an inner cylindrical waist 44a of the pivoting socket 44. The waist 44a is lined by a cup seal 45 to exclude draft between the head 102a and the pivoting socket 44. The head 102a is seated in a partially spherical inner face 48 of the annular trim 46 so that the head 102a may be p!voted and rotated in relation to the pivoting socket 44. The luminaire 100 is free to rotate about the longitudinal axis X-X in the clockwise direction R and in an anft-clockwise direction R'. Likewise, the uminaire 100 is free to pivot by an angle of up to 30 degrees from the longitudinal axis X-X. Thus, light from the luminaire 100 may be directed according to user preferences. The luminaire 100 may be removed from the pivoting socket 44 by reversing the snap-fit engagement between the annular web 106 and the internal groove 38. This facilitates replacement and repair of the luminaire 100 or retro-fitting of a different variety of luminaire, provided that it has the same design of head 102a.

Intumescent seals IS are located between the base 20 and the luminaire support 30, between the pivoting socket 44 and the cylindrical collar 22 and between the annular web 106 and the casing 102 of the luminaire 100. In the case of fire, the intumescent seals IS expand to fill air gaps to that the spread of fire is retarded by the light fitting 10.

Intumescent seals are common in the field of lighting and are not discussed in any more detail.

The light fitting 10 comprises an adjustable coupling mechanism configured to couple, decouple and adjust the luminaire support 30 in relation to the base 20. The coupling mechanism comprises the three sets of lobes 50a-50c, recesses 52a-52c, ramps 54a-54c, raised steps 56a-56c and parking steps 58a-58c in the base collar 22 and the three sets of teeth 60,62,64,66 on the support coflar. 32 The coupling mechanism is operable by way of manipulation of the luminaire support 30 as is explained in detail below. This manipulation may be by frictional contact between an installer's fingers and the luminaire support 30 which could be supplemented by, for example, finger grips.

Alternatively, some form of connection, like, for example, magnets inside the luminaire support 30 may be used to temporarily connect with a special tool to facilitate manipulation of the luminaire support 30.

The inner diameter of the base collar 22 is slightly greater than the diameter of the imaginary circumference circumscribed by the teeth 6062,64,66. This permits rotation, in clockwise R and anti-clockwise R' directions, and axial movement, in the up direction A and down direction B, of the luminaire support 30 in relation to the base 20 and its longitudinal axis X-X.

Assembly of the light fitting 10 shall now be described. The base 20 is seated in a circular hole H in a substrate S with the base outer flange 24 flush against the substrate S to which the base 20 is firmly connected. Preferably, the base outer flange 24 is plastered over to increase adhesion between the base 20 and the substrate S and to improve aesthetics by concealing all but the luminaire 100 and its light. The outer end 22a may have a small circumferential rim to act as a barrier to the layer of plaster. An electrical power supply cable is pulled from the cavity C and through the base collar 32 for connection to a luminaire 100. The luniinaire 100 is connected to the luminaire support 30 as described above. The luminaire 100 and luminaire support 30 are ready to be coupled to the base 20 to unite the light fitting 10 and suspend the luminaire 100 from the substrate S. The installer holds the luminaire support 30 by the support collar 32 and/or the annular trim 46. The installer inserts the support collar 32 into the outer end 22a of the base collar 22 and slides the support collar 32 in the direction of arrow A towards the inner end 22b of the base collar 22. Movement of the luminaire support 30 in the direction of longitudinal axis X-X is guided by the teeth 60,62,64,66 sliding against an inner cylindrical face 23 of the base collar 22. There is sufficient clearance between the teeth 60,62,64,66 and the inner cylindrical face 23 to ensure that friction is negligible. Each of the innermost teeth 66 is aligned with a respective recess 52a-52c in the support inner flange 36. If the innermost teeth 66 are not correctly aligned with the recesses 52a-52c, the installer, reiying on trial and error, rotates the lurninaire support 30 about longitudinal axis X-X until they are. The innermost teeth 66 pass just above the base inner flange 26. Note that the innermost teeth 66 cannot continue very far in the direction of arrow A because in a short distance the inner teeth 64 abut underside of the base inner flange 26.

Referring to Figures 9 to 12, operation of the adjustable coupling mechanism and, in particular, engagement between the teeth 60,62,64,66 and parts of the support inner flange 26 shall be described. The installer manually rotates the luminaire support 30 in the anti-clockwise direction R' towards the ramps 54a54c formed in the base inner flange 26.

The ramps 54a-54c are inclined by angle y of the helical path HP with respect to a plane orthogonal to the longitudinal axis X-X. Upon engagement between each innermost tooth and a respective ramp 54a-54c the luminaire support 30 rises a small way in the direction of arrow A and follows a helical path HP for about 30 degrees of rotation about the longitudinal axis X-X. One such innermost tooth in this position is shown as 66' in Figure 9.

The installer may choose to continue rotating the luminaire support 30 along the helical path HP for another 30 degrees of rotation until each innermost tooth 66 is above a respective raised step 56a-56c. One such innermost tooth in this posftion is shown as 66' in Figure 9. At this stage each inner tooth 64 is axiafly aligned with a respective recess 52a-52c in the support inner flange 26. The installer has each inner most tooth 66 above a respective raised step 56a-56c before deciding what to do next. Here, the installer has two choices.

Either the installer chooses to continue rotating the luminaire support 30 in the anti-clockwise direction R', but below the helical path HP, for another 30 degrees of rotation about the longitudinal axis X-X until each innermost tooth abuts a respective lobe 50a-50c.

The inner teeth 64 remain below the support inner flange 36. Rotation in the anti-clockwise direction R' is stopped by the lobes 50a-50c and each innermost tooth 66 may be allowed to drop (under gravity if, as is often the case, the longitudinal axis X-X is orientated substantially vertically) in the direction of arrow B into a respective parking step 58a-58c located after a non-return lip 68a-68c of the adjacent raised step 56a-56c. One such innermost tooth in this position is shown as 66' in Figure 9. Any further rotation of the luminaire support 30 in the anti-clockwise direction R' is arrested by contact between each innermost teeth 66" and a respective lobe 50a-50c which acts as a stop. The luminaire support 30 is coupled to the base 20 in an extended position, as is shown by figures 5 and 9.

Alternatively, the installer chooses to continue rotating the luminaire support 30 in the anti-clockwise direction R', along the helical path HP, for another 30 degrees of rotation about the longitudinal axis X-X. This causes each inner tooth 64 to pass through a respective recess 52a-52c to just above the base inner flange 26. Upon engagement between each inner tooth 64 and a respective ramp 54a-54c the luminaire support 30 continues to rise a small way in the direction of arrow A. Eventually, the inner tooth 64 adopts the position previously occupied the innermost tooth at 66' in Figure 9. This perpetuates the helical path HP for about 30 degrees of rotation about the longitudinal axis X-X because sliding engagement between the inner teeth 64 and the ramps 54a-54c directs the innermost teeth over the lobes 50a-50c, One such innermost tooth in this position is shown as 66" in Figure 9.

Referring to Figure 10, the installer may choose to continue rotating the luminaire support 30 along the helical path HP for another 30 degrees of rotation until each inner tooth 64 is above a respective raised step 56a-56c. One such inner tooth in this position is shown as 64" in Figure 10. At this stage, each outer tooth 62 is axia!ly aligned with a respective recess 52a-52c in the support inner flange 26. The instafler has each inner tooth 64 above a respechve raised step 56a-56c before deciding what to do next. Here, the instaUer is faced with the same two choices.

Either the instaer chooses to continue rotating the luminaire support 30 in the anti-dockwise direction R', but bebw the hehcal path HP, for another 30 degrees of rotation about the longitudinal axis X-X until each inner tooth abuts a respective obe 50a-50c. The outer teeth 62 remain below the support inner flange 26. Rotation in the anti-clockwise direction R' is stopped by the obes 50a-50c and each inner tooth may be aflowed to drop in the direction of arrow B into a respective parking step 58a-58c behind a non-return lip 68a-68c of the adjacent raised step 56a-56c. One such inner tooth in this position is shown as 64'" in Figure 10. Further rotation of the luminaire support 30 in the anti-clockwise direction R' is arrested by contact between each inner teeth 64 and a respective lobe 50a-50c which acts as a stop. The luminaire support 30 is coupled to the base 20 in a partially retracted position. The partially retracted position is located behind the extended position (in the direction of arrow A) by as much as the axial distance between the innermost and inner teeth 64,66.

Alternatively, the installer chooses to continue rotating the luminaire support 30 in the anti-clockwise direction R', along the helical path HP, for another 30 degrees of rotation about the longitudinal axis X-X. This causes each outer tooth 62 to pass through a respective recess 52a-52c to just above the base inner flange 26. Upon engagement between each outer tooth 62 and a respective ramp 54a-54c the luminaire support 30 continues to rise a small way in the direction of arrow A. Eventuaily, the outer tooth 62 adopts the position previously occupied the inner tooth at 64' in Figure 10. This perpetuates the helical path HP for about 30 degrees of rotation about the longitudinal axis X-X because sliding engagement between the outer teeth 62 and the ramps 54a-54c directs the inner teeth over the lobes 50a-50c. One such inner tooth in this position is shown as 64" in Figure 10.

Referring to Figure 11, the installer may choose to continue rotating the luminaire support 30 along the helical path HP for another 30 degrees of rotation until each outer tooth 62 is above a respective raised step 56a-56c. One such outer tooth in this position is shown as 62" in Figure 10. At this stage, each outermost tooth 60 is axially aligned with a respective recess 52a-52c in the support inner flange 26. The installer has each outer tooth 62 above a respechve raised step 56a-56c before deciding what to do next. Here, the insta!ler is faced with the same two choices.

Either the instaUer chooses to continue rotaUng the luminaire support 30 in the anti-clockwise direction R', but below the hehcal path HP, for another 30 degrees of rotation about the longftudinal axis X-X until each outer tooth abuts a respective obe 50a-50c. The outermost teeth 60 remain b&ow the support inner flange 26. Rotation in the anti-clockwise direction R' is stopped by the lobes 50a-50c and each outer tooth may be allowed to drop in the direction of arrow B into a respective parking step 58a-58c behind a non-return lip 68a-68c of the adjacent raised step 56a-56c. One such outer tooth in this position is shown as 62'' in Figure 11. Further rotation of the luminaire support 30 in the anti-clockwise direction R' is arrested by contact between each outer teeth 62 and a respective lobe bOa-SOc which acts as a stop. The luminaire support 30 is coupled to the base 20 in a second partially retracted position. The second partially retracted position is located behind the extended position (in the direction of arrow A) by as much as the axial distance between the innermost and outer teeth 66,62.

Alternatively, the installer chooses to continue rotating the luminaire support 30 in the anti-clockwise direction R', along the helical path HP, for another 30 degrees of rotation about the longitudinal axis X-X. This causes each outermost tooth 60 to pass through a respective recess 52a-52c to just above the base inner flange 26. Upon engagement between each outermost tooth 60 and a respective ramp 54a-54c the luminaire support 30 continues to rise a small way in the direction of arrow A. Eventually, the outermost tooth 60 adopts the position previously occupied the outer tooth at 62' in Figure 11. This perpetuates the helical path HP for about 30 degrees of rotation about the longitudinal axis X-X because sliding engagement between the outermost teeth 60 and the ramps 54a-54c directs the outer teeth over the lobes 50a-bOc. One such outer tooth in this position is shown as 62'" in Figure 11.

The external channel 34 cannot pass the support inner flange 36. Abutment between the external channel 34 and the underside of the inner flange 36 prevents continuation along the helical path HP. The installer continues rotating the luminaire support 30 generally in the anti-clockwise direction R' for another 60 degrees of rotation about the longitudinal axis X-X until each outermost tooth abuts a respective lobe 50a-50c.

Here each outermost tooth 60 may be allowed to drop in the direction of arrow B into a respective parking step 58a-58c behind a non-return lip 68a-68c of the adjacent raised step 56a-56c. One such outermost tooth in this position is shown as 60" in Figure 12. Any further rotation of the luminaire support 30 in the anti-clockwise direction R' is arrested by contact between each outermost teeth 60 and a respective lobe 50a-SOc which acts as a stop. The luminaire support 30 is coupled to the base 20 in a retracted position. The retracted position is located behind the extended position (in the direction of arrow A) by as much as the axial distance between the innermost and outermost teeth 66,60. In the present example, this axial distance is approximately 20mm to 30mm.

The light filling 10 may be disassembled by reversing the assembly method described above. Disassembly may be initiated at any one of the extended, partially retracted, second partially retracted or retracted positions. Initially, the installer gently moves the luminaire support 30 in the direction of arrow A until whichever teeth 60,62,64,66 previously in engagement with the parking steps 58a-58c are lifted clear of the non-return lips 68a-68c and the ramps 54a-54c and rotated in the clockwise direction R along the helical path HP preferably guided by engagement between the teeth and the ramps. Rotation along the helical path HP in the clockwise direction R may continue until each innermost tooth 66 exits a respective recess 52a-52c. At this stage the luminaire support 30 is decoupled from the base 20. Alternatively, rotation along the helical path HP in the clockwise direction R may be reversed at some point if the installer decides to move between one of the extended, partially retracted, second partially retracted or retracted positions rather than decouple the base 20 and the luminaire support 30.

The axial distance between teeth of the adjustable coupling mechanism and/or the circumferential distance between these teeth may be varied according to the particular size or application of the luminaire support 10. Likewise, each set of teeth may have fewer or more than four teeth to provide fewer or more retracted positions behind the extended position. Ideally, although not necessarily, such variations may have consecutive teeth of each set that define a substantially helical path about the circumference of the outer cylindrical face 33 of the collar 32 so that smooth adjustment of the adjustable coupling mechanism is preserved.

The advantage with the adjustable coupling mechanism described above is that it may couple, decouple and adjust the luminaire support 30 in relation to the base 20. This is achievable within the sweep of the helical path HP which is equivalent to the circumferential sweep between the innermost tooth 66 and the outermost tooth 60 of each set of teeth (i.e. angle 13 multiplied by six = 180 degrees). This allows adjustment of the position of the luminaire support 30 without any significant twist to the electrical power supply cables attached to the luminaire 100. Another advantage wfth the adjustable coupling mechanism is that the height differences between the lobes 50a-50c and the non-return lips 68a-68c on the one hand, and the parking step 58a-58c on the other hand, provide a tactile indication to the installer of when the luminaire support has reached one of the extended, partiaUy retracted, second partially retracted or retracted positions.

Passage along the helical path HP is assisted by the ramps 54a-54c which help guide a substantially smooth rotation of the teeth about the longitudinal axis X-X.

Claims

Claims 1. A light fitting for recessed mounting of a luminaire in a substrate, the light fitting comprising: a base having a longitudinal axis; a luminaire support; and an adjustable coupling mechanism operable to adjust the position of the luminaire support in relation to the base along both directions of the longitudinal axis of the base and wherein the adjustable coupling mechanism is operable by way of manipulation of the luminaire support to couple or decouple the luminaire support from the base.
2. A light fitting as claimed in claim 1, wherein the coupling mechanism is operable by way of manipulation of the luminaire support to adjust the position of the luminaire support in relation to the base along both directions of the longitudinal axis of the base.
3. A light fitting as claimed in either one of claims 1 or 2, wherein the coupling mechanism is operable by rotation of the luminaire support in relation to the base.
4. A light fitting as claimed in any one of claims, wherein the position of the luminaire support in relation to the longitudinal axis of the base is adjustable in increments.
5. A light fitting as claimed in any one of the previous claims, wherein the base comprises a collar configured for recessed mounting in a substrate.
6. A light fitting as claimed in claim 5, wherein the collar comprises a hollow cylinder and the luminaire support is configured to telescope within the collar.
7. A light fitting as claimed in any one of the previous claims, wherein the base has an outer end and an inner end at an opposite longitudinal end of the base to the outer end and wherein luminaire support is adjustable between an extended position substantially at the outer end and a retracted position distal from the outer end.
8. A light fitting as claimed in claim 7, wherein the outer end of the base comprises an outer flange configured for engagement with a substrate.
9. A light fitting as claimed in any one of the previous claims, wherein the light fitting further comprises a luminaire connected to the luminaire support.
10. A light fitting as claimed in claim 9, wherein the luminaire is pivotal in relation to the luminaire support about the longitudinal axis of the support.
11. A light fitting as claimed in either one of claims 9 or 10, wherein the luminaire is releasably connected to the luminaire support.
12. Alight fitting as claimed in claim 9, wherein the luminaire support is integral with the I u m in a ire.
13. A light fitting as claimed in any one of the previous claims, wherein the coupling mechanism comprises: a tooth arrangement on one of the base or the luminaire support; and a tooth engagement arrangement on the other of the base or the luminaire support, wherein the tooth arrangement is engagable with the tooth engagement arrangement to couple the luminaire support in at least two different positions in relation to the longitudinal axis of the base and wherein the tooth arrangement is disengagable from the tooth engagement arrangement to decouple the luminaire support from the base.
14. A light fitting as claimed in claim 13, wherein the tooth arrangement comprises at least one set of a plurality of teeth and wherein each tooth is offset from the next consecutive tooth of the same set in the direction of the longitudinal axis of the base.
15. A light fitting as claimed in claim 14, wherein each tooth is offset from the next consecutive tooth of the same set in a direction of rotation about the longitudinal axis of the base.
16. A light fitting as claimed in either one of claims 14 or 15, wherein the tooth arrangement comprises a plurality of sets of teeth.
17. A light fitting as claimed in claim 16, wherein the sets of teeth are arranged at equiangular intervals about the longitudinal axis of the base.
18. A light fitting as claimed in any one of claims 14 to 17, wherein the tooth engagement arrangement comprises a shelf for the or each set of teeth.
19. A light fitting as claimed in claim 18, wherein the or each shelf comprises a respective portion for retaining a tooth.
20. A light fitting as claimed in claim 19, wherein the or each shelf comprises a respective ramp.
21. A light fitting as claimed in either one of claims 19 or 20, wherein the or each shelf comprises a respective stop.
22. A light fitting as claimed in any one of claims 19 to 21, wherein the coupling mechanism is operable by rotation of the luminaire support in relation to the base about a substantially helical path.
23. A light fitting as claimed in claim 22, wherein the or each portion for retaining a tooth is located outside the substantially helical path.
24. A light fitting as claimed in any one of claims 13 to 23, wherein the base comprises the tooth engagement assembly and the luminaire support comprises the tooth assembly.
25. A light fitting as claimed in any one of the previous claims, wherein the adjustable coupling mechanism is operable by way of manual grip of the luminaire support optionally facilitated by finger grip on the luminaire support or by way of manipulation with a special tool optionally including magnetic connection to the luminaire support.
26. A base having a longitudinal axis, wherein the base is configured to be coupled to the luminaire support of the light fitting of any one of the previous claims.
27. A luminaire support configured to be coupled to the base having a longitudinal axis of the light fitting of any one of claims 1 to 25.
28. A light fitting assembly substantially as hereinbefore described with reference to the drawings.
29. A base substantially as hereinbefore described with reference to the drawings.
30. A luminaire support substantially as hereinbefore described with reference to the drawings.Amendments to the claims have been filed as follows Claims 1. A light fitting for recessed mounting of a luminaire in a substrate, the light fitting comprising: a base having a longitudinal axis; a luminaire support; and an adjustable coupling mechanism operable to adjust the position of the luminaire support in relation to the base along both directions of the longitudinal axis of the base, wherein the adjustable coupling mechanism is operable by way of manipulation of the luminaire support to couple or decouple the luminaire support from the base and wherein the coupling mechanism is operable by rotation of the luminaire support in relation to the base about the longitudinal axis of the base.2. A light fitting as claimed in claim 1 wherein the coupling mechanism is operable by way of manipulation of the luminaire support to adjust the position of the luminaire support cJ in relation to the base along both directions of the longitudinal axis of the base.0') 3. A light fitting as claimed in either one of claims 1 or 2, wherein the position of the 0.. . . .. . luminaire support in relation to the longitudinal axis of the base is adjustable in increments. (Si4. A light fitting as claimed in any one of the previous claims, wherein the base comprises a collar configured for recessed mounting in a substrate.5. A light fitting as claimed in claim 4, wherein the collar comprises a hollow cylinder and the luminaire support is configured to telescope within the collar.6. A light fitting as claimed in any one of the previous claims, wherein the base has an outer end and an inner end at an opposite longitudinal end of the base to the outer end and wherein luminaire support is adjustable between an extended position substantially at the outer end and a retracted position distal from the outer end.7. A light fitting as claimed in claim 6, wherein the outer end of the base comprises an outer flange configured for engagement with a substrate.8. A light fitting as claimed in any one of the previous claims, wherein the light fitting further comprises a luminaire connected to the luminaire support.9. A light fitting as claimed in claim 8, wherein the luminaire is pivotal in relation to the luminaire support about the longitudinal axis of the support.10. A light fitting as claimed in either one of claims 8 or 9, wherein the luminaire is releasably connected to the luminaire support.11. A light fitting as claimed in claim 8, wherein the luminaire support is integral with the luminaire.12. A light fitting as claimed in any one of the previous claims, wherein the coupling mechanism comprises: a tooth arrangement on one of the base or the luminaire support; and a tooth engagement arrangement on the other other of the base or the luminaire support, 0') wherein the tooth arrangement is engagable with the tooth engagement arrangement to couple the luminaire support in at least two different positions in relation to the longitudinal C\J axis of the base and wherein the tooth arrangement is disengagable from the tooth engagement arrangement to decouple the luminaire support from the base.13. A light fitting as claimed in claim 12, wherein the tooth arrangement comprises at least one set of a plurality of teeth and wherein each tooth is offset from the next consecutive tooth of the same set in the direction of the longitudinal axis of the base.14. A light fitting as claimed in claim 13, wherein each tooth is offset from the next consecutive tooth of the same set in a direction of rotation about the longitudinal axis of the base.15. A light fitting as claimed in either one of claims 13 or 14, wherein the tooth arrangement comprises a plurality of sets of teeth.16. A light fitting as claimed in claim 15, wherein the sets of teeth are arranged at equiangular intervals about the longitudinal axis of the base.17. A light fitting as claimed in any one of claims 13 to 16, wherein the tooth engagement arrangement comprises a shelf for the or each set of teeth.18. A light fitting as claimed in claim 17, wherein the or each shelf comprises a respective portion for retaining a tooth.19. A light fitting as claimed in claim 18, wherein the or each shelf comprises a respective ramp.20. A light fitting as claimed in either one of claims 18 or 19, wherein the or each shelf comprises a respective stop.21. A light fitting as claimed in any one of claims 18 to 20, wherein the coupling mechanism is operable by rotation of the luminaire support in relation to the base about a substantially helical path.T" 22. A light fitting as claimed in claim 21, wherein the or each portion for retaining a tooth Cs,J is located outside the substantially helical path. rIf) 23. A light fitting as claimed in any one of claims 12 to 22, wherein the base comprises the tooth engagement assembly and the luminaire support comprises the tooth assembly.24. A light fitting as claimed in any one of the previous claims, wherein the adjustable coupling mechanism is operable by way of manual grip of the luminaire support optionally facilitated by finger grip on the luminaire support or by way of manipulation with a special tool optionally including magnetic connection to the luminaire support.25. A base having a longitudinal axis, wherein the base is configured to be coupled to the luminaire support of the light fitting of any one of claims 12 to 23 or claim 24 when appended to any one of claims 12 to 23 by the adjustable coupling mechanism of any one of claims 12 to 23 or claim 24 when appended to claim 12.26. A luminaire support configured to be coupled to the base having a longitudinal axis of the light fitting of any one of claims 12 to 23 or claim 24 when appended to any one of claims 12 to 23 by the adjustable coupling mechanism of any one of claims 12 to 23 or claim 24 when appended to any one of claims 12 to 23. (4 rLO27. A light fitting assembly substantially as hereinbefore described with reference to the drawings.28. A base substantially as hereinbefore described with reference to the drawings.29. A luminaire support substantially as hereinbefore described with reference to the drawings. a) (Si (4