A LIGHT FITTING

FIELD OF THE INVENTION

The invention relates to a light fitting and to a chamber including a light source, in particular, an array of LEDs.

BACKGROUND OF THE INVENTION

There are a number of light fittings on the market. These may be for use indoors or outdoors. Light fittings are often made for specific applications and to specific requirements. Examples of these are fittings mounted in the ground, in a wall or submerged in water such as those used in swimming pools. One such light fitting is disclosed in International patent application number PCT/IB2007/052227.

The particular fittings to which this invention is directed include suitable components and a light source. These are contained in a casing or, sometimes, more than one casing. The fittings are assembled and supplied ready for installation. Access to inside the fittings is usually afforded through a hatch or cover of some sort. Some fittings may be manufactured in a manner that does not afford access to the contents without breaking the casing.

OBJECT OF THE INVENTION

It is an object of this invention to provide a novel light fitting and a chamber for a light source.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a light fitting which includes a chamber moulded from transparent plastics material and a lens fixed to the chamber.

The invention further provides for the chamber and lens to be moulded from the same transparent material; for the chamber to have an annular lip against which the lens is fixed; and for an annular flange to fit into a recess at the edge of the lens; the flange, lens and lip having aligned holes through which screws extend to engage threaded nuts.

Further features of the invention provide for an electrical cable extending into the chamber to be embedded in a settable resin; and for a portion of the cable which is embedded to be stripped of its outer insulation sheath.

Further features of the invention provide for the fitting to be of the kind for mounting substantially flush with a surface and to include an outer housing in which the chamber is located; and for the chamber to contain a light emitting diode (LED) array with the electronic components for the LEDs located in the housing.

The invention extends to a chamber and lens for a light fitting that are moulded from the same transparent plastics material; preferably polycarbonate.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described, by way of example only, with reference to the specific embodiment of the accompanying drawings, in which:

Figure 1 shows a cross-sectional side view of the light fitting; Figure 2 shows a perspective view of the inner chamber; Figure 3 shows an exploded view of the chamber in Figure 2; and Figure 4 shows a perspective view of the fitting with part of the outer housing cut away.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the Figure 1 , a light fitting (1 ) in accordance with this invention is shown. The fitting (1 ) has an array of three LEDs as a light source (2) which are contained in a double casing (20).

More specifically, the light source (2) is mounted in an inner chamber (3). A lens (5) is secured over an open end of the chamber (3). The LED's (2) will be supported in position behind the lens (5).

In this example, the chamber (3) is waterproof. The fitting (1 ) serves as an in- ground light or can be mounted flush into a wall or some other surface.

On assembly of the fitting (1 ), the lens (5) is mounted in an annular flange (6), preferably made of aluminium. The lens (5) has a recess at its edge into which the flange (6) is located.

A lip (7) on the chamber (3) provides a sealing surface for the lens (5). These components (5), (6) and (7) are secured together by a series of screws (6.2). The screws (6.2) engage in nuts (6.3) which fit into openings in the bottom of lip (7).

The casing (20) includes an exterior housing (8) that is similarly configured to the chamber (3) but made from aluminium. Two of the screws (6.2) referred to will be sufficiently long to engage in threaded holes (not shown) in a lip (9) on the housing (8) to hold the chamber (3) in place. The housing (8) will usually have two laterally extending lugs (not shown) which serve to anchor the fitting when the installation is made. The chamber (3) can be removed from the housing (8) by undoing the two screws (6.2).

A dish-shaped aluminium support (10) which serves as a heat sink is located inside the chamber (3). The LED's are mounted on a printed circuit board (11 ) which is fixed to the support (10). The support (10) is suspended centrally in the chamber (3) from pair of oppositely arranged brackets (13). The brackets (13), which are made of steel, are secured in place by embedding them in a settable potting resin (14). A suitable epoxy will be used.

The chamber (3) will preferably be moulded with two oppositely arranged pairs of parallel ribs (not shown) extending inwardly from the sidewalk Each pair of ribs provides a guide to locate a bracket (13) before the resin is poured.

A cable (21 ) passes into the housing (8) to supply electricity to the light source (2). A second cable (not shown), exiting the housing (8), is optional for connection to another light fitting. The supply cable (21 ) extends into the housing (8) through a gland (22) for connection through the necessary electronic components (23) to the LEDs (2) in the chamber (3).

The potting resin (14) is primarily provided to waterproof the bottom of the chamber (3), where an opening is necessary for the cable (21 ). Once the electrical cable (21 ) is fitted, the resin (14) is poured into the chamber. This sets over cable (21 ) where it extends into the chamber (3). A portion of the cable (21 ) in the chamber (3) is stripped of its exterior insulation sheath where it extends

through the resin (13). This leaves bare or exposes inner insulation wires (23) which are then also embedded in the resin (14). A barrier against moisture penetration which sometimes takes place through capillary action is thus also provided.

The electronic components (24) for the LEDs (2) are shown in the outer housing (8) but could also be located inside the chamber (3) behind the LEDs. The electronics (24) will also be potted with epoxy resin.

The chamber (3) is made as a single component from rigid plastics material which, in accordance with this invention, is selected to be of a transparent kind. A type of thermoplastic polymer is preferably used and this is moulded integrally to form through injection moulding.

The plastics material for the chamber (3) will preferably be Polycarbonate (PC). The lens (5) which seals onto the chamber (3) is moulded from the same material. The chamber (3) and/or lens (5) may have an annular groove for location of a ring seal (not shown) therebetween.

Other examples of materials which could be used include acrylic resins, such as polymethyl methacrylate (PMMA); Polyvinyl chloride (PVC); or acrylonitrile butadiene styrene (ABS). Materials of this kind allow for recycling.

These materials will be selected depending on the application or requirements of the fitting. ABS has good qualities of impact resistance, toughness, and heat resistance. PMMA is its highly transparent and also resistant to sunlight. The characteristics of polycarbonate are similar to those of PMMA, but it is stronger.

If or when the LED light source (2) fails, a visual inspection of the contents should allow for easy diagnosis without having to open the fitting (1 ). This is significant,

particularly with LED technology, where the electronic components show signs of malfunction.

Light fittings of this kind are frequently exposed to moisture. It is undesirable but often necessary to open the sealed casing components to check for faults or moisture ingress. Once the initially established seal has been broken or is tampered with, it is often difficult to re-establish a seal with the same effectiveness. The advantage of a visual inspection without having to take apart the components will be appreciated by those familiar with these fittings.

The arrangement or location of the component parts will preferably also facilitate easy inspection. In other words, the components are placed where they can be easily seen through the chamber wall. Various configurations will be within the design competence of a suitably skilled person. Where necessary, the support (10) will also be transparent or otherwise suitably configured to enable visual inspection of the chamber contents.

In addition to this, the light fittings are assembled with electronic components sourced form different suppliers. The transparent chamber (3) enables visual verification of the brand and, therefore, quality of the components. Easy evaluation as to the quality of a fitting can be made by a suitably skilled person.

While the embodiment described has an LED light source, it will be appreciated that the invention extends to a number of other fittings which may have different light sources. The advantage of being able to see the build quality is particularly relevant to these products generally. This will apply to any fitting whether for use indoors or outdoors and however it is mounted.

For a fitting such as the one disclosed in PCT/IB2007/052227 bother the inner chamber and outer housing, which each provide a waterproof seal, can be moulded from transparent material.

A person skilled in the art will appreciate that a number of variations can be made to the described examples without departing from the scope of the current invention.