FIELD OF THE INVENTION

The invention relates to an overhead light fitting of the kind used facing downwardly usually beneath a roof and mounted within a supporting structure for ceiling tiles or panels.

BACKGROUND TO THE INVENTION

Conventionally ceiling mounted light fittings include a frame. To the frame is mounted or fastened the required electric circuitry and, where relevant, light source or bulb fittings.

In some cases, such as with fluorescent or incandescent lights, the frame supports electrical sockets to removably receive the light bulbs. Other ceiling mounted frames have mechanisms to hold a light bulb or other light source captive and an electrical supply line which lies loose in the ceiling with a connector on the end of the line that fits onto the terminals of the bulb.

Changing bulbs and capacitors (depending on the nature of the bulb) can be inconvenient as a result of light diffusers or reflectors which need to be removed, for example. Circular socket type fittings of the kind used on round profile down-lights can lose their shape which makes it difficult to re-insert face-clips that hold the down-lights in place.

There are also light fittings which incorporate light emitting diodes (LEDs). These fittings are assembled with all the required components fixed to a ceiling mountable frame and the required electrical supply line leading therefrom. The LEDs are secured within the assembly. When an LED fails, the whole assembly must usually be removed, opened and the LEDs replaced. The LED housing components are held captive on the frame structure or inside a housing fastened thereto.

OBJECT OF THE INVENTION

It is an object of the invention to provide a light fitting that is simple and convenient to maintain in working order, to transport and to install.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided an overhead light fitting comprising:

a frame having an opening between an upper side and a lower side,

a replaceable luminaire module provided as a body with a light source and an electrical supply connection,

the frame providing a cradle for the module,

the cradle releasably supporting the module in alignment with and over the opening, and

removal of the module effected by lifting from the cradle with the frame remaining in an installed position.

The invention further provides for the module to be supported by a pair of oppositely disposed upwardly facing shoulders provided within the cradle and maintained in position against the shoulders by gravity. A further feature of the invention provides for the module to be a sliding, clearance fit into the cradle from the upper side of the frame. [Alternatively, a resiliently deformable component may provide an interference fit between the module and cradle.]

A further feature of the invention provides for the shoulders to be provided by the frame around the opening.

A further feature of the invention provides for the cradle to include a guide around the opening to maintain alignment of the module.

Further features of the invention provide for the guide to be provided on the upper side of the frame; for the guide to be provided by a flange (or flanges) adjacent each shoulder; and/or, for the guide to be provided within the opening; and for the guide to be provided by (at least part of) a sidewall or edge of the opening.

[As a further alternative, the cradle may have a tapered configuration (or include components of such orientation) which will allow a module with corresponding engaging formations to rest in the cradle (in the required aligned orientation).]

Further features of the invention provide for the frame be provided as a faceplate for the light fitting; and for the frame to be configured to fit into a ceiling tile support structure; alternatively, for the frame to be provided as a box for suspension from a roof structure.

Further features of the invention provide for the frame to be made from a sheet of suitably rigid material, preferably metal; and for the guide to be provided by a flange secured spaced apart from and around the opening.

Further features of the invention provide for the luminaire module to include LEDs secured inside the module body having an integrally connected electrical supply line fitted with an inline LED driver and having the electrical supply connection provided on the end of the line; and for the electrical supply connection to be a plug for connection to an electrical socket associated with the light fitting.

The invention extends to a luminaire module provided as a body with a light source and an electrical supply connection for use with a frame of the light fitting defined above.

Further features of the invention provide for the module to include LEDs secured inside the body with an integrally connected electrical supply line fitted with an inline LED driver and having the electrical supply connection provided on the end of the line; and for the electrical supply connection to be a plug for connection to an electrical socket associated with the light fitting.

Further features of the invention provide for the body to be an extruded channel; for the channel to include a pair of opposed grooves to receive a diffuser lens; for the channel to be fitted with end plates which cover edges of the lens.

In accordance with another aspect of the invention there is provided a method of providing and maintaining a light fitting installation comprising installing a frame as defined above and fitting a luminaire module as defined above by connecting the electrical connection of the module to a corresponding, plug-in power supply connection associated with the light fitting and lowering the module into the cradle over the opening in the frame; and, when the module requires replacement: a. removing the existing module by lifting it from the cradle and disconnecting the electrical connection, and

b. fitting a replacement module by connecting the electrical connection of the replacement module to the plug-in power supply connection and lowering the replacement module into the cradle over the opening in the frame. BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the invention will become more apparent from the following descriptions of one embodiment, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a part cross-sectional view of a light fitting in accordance with the invention;

Figure 2 shows an enlarged view of a luminaire module in a cradle of the fitting in Figure 1 ;

Figure 3 shows a top perspective view of the light fitting with one module in place and another removed; and

Figure 4 shows bottom perspective view of the light fitting.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, a light fitting (1 ) suited for use in a ceiling includes a frame (2) and a pair of luminaire modules (3).

The frame (2) is configured to fit into a ceiling tile supporting rail structure (not shown). More particularly, in this embodiment, the frame (2) is provided with a square border, of 600 mm x 600 mm. This corresponds to half the size of a ceiling tile or panel of 600 mm x 1200 mm.

Such a ceiling tile can be cut in half and a cross-support rail fitted as required across the (removed) ceiling tile opening in the supporting rail structure. The frame (2) will be dropped into place to one side of the dividing rail (replacing one half of the removed tile).

The luminaire modules (3) each have an electrical supply line (4) fitted with a plug (not shown), which may be of any convenient configuration. The modules (3) will be plugged into electricity supply sockets (of corresponding configuration) in the ceiling and fitted to the frame (2), in the manner described below. The other half of the ceiling tile is then located on the other side of the dividing rail to complete the installation.

It will be appreciated that a dividing rail will be optional and the frame (2) and half ceiling tile may simply be laid side-by-side in the supporting rail structure. The frame (2) may of course also be made to the same dimensions as a whole ceiling tile.

The frame (2) accordingly has an upper side (5) and a lower side (6). An opening (7) is provide for each of the modules (3) which fit to the upper side

(6) of the frame (2).

In accordance with the invention, the frame (2) provides a cradle (8) for each module (3). The cradle (8) releasably supports the module (3) in alignment with and over the opening (7) with engagement of the module (3) within the cradle (8) maintained in use by gravity.

The cradle (8) includes an upwardly facing shoulder (9) around the opening

(7) to support the module (3). The shoulder (9) receives the weight of the module (3) and supports t in place over the opening (7). The cradle (8) further includes a guide (10) to maintain alignment of the module (3) with the opening. The module (3) of the invention is preferably a sliding clearance fit into the cradle (8).

The fit referred to will thus be understood to be a drop-fit into the guide (10) and onto the shoulder (9).

In the fitting (1 ) as illustrated, the guide (10) is be provided to an upper side of the shoulder (9) by a flange (1 1 ). The flange (1 1 ) secured to the frame (2), around the shoulder (9) and thus spaced apart from the edge of the opening (7).

The frame (2) is made from sheet metal. The corners of the sheet are cut out and the sections between the cut-outs pressed back to provide a peripheral lip (12) at the border of the frame (2). The frame (2) is accordingly provided with a planar underside (6) which forms a face plate for the light fitting (1 ).

The luminaire module (3) includes LEDs secured inside a module body (13). The body (13) is provided as an extruded channel. The electrical supply line (4) is wired to an LED support mounted inside the body (13). In this embodiment, an LED driver (4.1 ) is provided in the electrical supply line (4).

The channel of the body (13) includes a pair of opposed grooves, the outer profiles of which are indicated by (14) adjacent the free edges of the channel flanges (13.1 ). These grooves slidingly receive the sides of a rectangular diffuser lens (15), which is fitted from an end of the channel (13).

A pair of lipped grooves (not shown), each provided by inwardly curved flanges, are extruded inside the body (13) along the channel web (13.2) adjacent to where it meets the channel flanges (13.1 ). The lipped grooves receive fastening screws (16) that secure profiled end plates (17) in place. The plates (17) fit over the edges of the lens (15) at the open ends of the channel (13) and retain it within the body (13).

The module (3) is accordingly provided as an enclosed casing with the lens (15) locatable over the opening in the frame (2).

The invention accordingly provides a light fitting which enables tools-free installation and changing out and replacement of luminaire modules. Spare modules for convenient and quick replacement can be kept on site. The lay-in cradle and module engagement makes for extremely easy changes and serves to provide for proper alignment of the modules.

The electrical supply circuitry may include a back-up supply unit with battery where this is desired.

The construction of the fitting enables separate packing of the frames and modules. This makes for efficient use of space. The frames can be stacked and the modules boxed with little wasted space. The advantage is significant where packing is required for transport.

The disclosed embodiment of the invention accordingly provides an overhead light fitting which includes a frame suited for easy installation and providing a face-plate with an opening and a cradle on the upper side of the opening to loosely receive a replaceable luminaire module. The cradle and module are configured for the latter to be a drop-fit into the cradle, which maintains the module in alignment over the opening, where it is held in place by gravity. Removal of the module for replacement is effected by lifting from the cradle with the frame remaining in an installed position.

It will be understood that the invention extends to a method of providing and maintaining such a light fitting installation, which when the module requires replacement, involves: removing the existing module by lifting it from the cradle and disconnecting the electrical connection, and fitting a replacement module by connecting the electrical connection of the replacement module to the plug-in power supply connection and lowering the replacement module into the cradle over the opening in the frame.

A person skilled in the art will appreciate that a number of variations may be made to the components of the fitting and module described without departing from the scope of the current invention.

For example, the frame could be provided as a ceiling plate or a box (preferably with an open top) suspended from a roof structure by cables (or some other suitable supporting structural elements, for example). This may suit use in a show room, or parking lot, or in buildings without ceilings or having double volume rooms.

The openings and modules could be of a different shape (round or square, for example). The number and configuration of LEDs inside the modules may accordingly also be varied. The guide (10) may alternatively or in addition be provided within the opening (7); by, for example, a sidewall or edge of the opening (7) (or at least part thereof). It will thus be understood that the module of the invention may be provided as a substantially plane sided body without any formations for cooperation with the cradle, or it may (for use with the variation to the guide referred to) have formations which fit or protrude (from the upper side of the frame) into the opening and allow alignment to be maintained in that manner.

As a further alternative, the cradle may have a tapered configuration (or include components of such orientation) that will allow a module with corresponding engaging formations to rest in the cradle (in the required aligned orientation). In such an embodiment, for example, the opening may include a pair of outwardly inclined flanges extending along and from the edges of opposite long sides or the edges of the narrow ends. Correspondingly inclined abutting surfaces on the module will provide the required guided (aligned) gravity maintained fit.

While the sliding, clearance fit referred to is considered a cost effective and practical configuration, it will be appreciated that the cradle or module may include a resiliently deformable component (or components) to provide an interference fit between the module and cradle. The components could be rubber or spring loaded clips or catches for example.