A known design for an underwater light fitting uses a separately replaceable bulb in a housing having a watertight seal between a casing at the rear of the housing and a plain glass face at the front of the housing. In use the light housing is installed in a niche in the side wall of the pool. Power is generally supplied via an insulated cable which emerges from some part of the niche wall and enters the housing via an aperture. The aperture includes a permanent seal, in order to prevent water from entering the housing. In use, the housing is cooled by water circulating in the space between the rear wall of the niche and the housing (and also, of course, by water in contact with the plain glass face at the front of the housing).

Holes may be provided in order to allow water to enter the niche, enhancing the cooling effect. When it is

necessary to replace the bulb or perform other maintenance the housing is demounted from the niche and lifted out of the water. The length of cable between the niche wall and the housing is generally about 1.5 yards (1.5m), this being sufficiently long to allow the housing to be lifted out of the water but sufficiently short to enable the cable to fit comfortably in the niche cavity behind the housing when the housing is mounted in the niche.

Clearly the light housing cannot be moved further away from the niche than the length of the cable permits without being disconnected from the cable. For this reason, work that must be performed, such as replacement of the bulb or other maintenance, is generally performed at the poolside. This is not necessarily a convenient place to perform such operations.

In order to replace the bulb the waterproof housing must be dismantled, normally by removal of the face from the rest of the housing. After replacement of the bulb, the housing must be reassembled ensuring that all seals are intact and in place so that the waterproof integrity of the housing is maintained.

Dismantling the housing may be difficult, since the fastenings are generally of metal and may be considerably corroded after spending a long period of time submerged in, for example, chlorinated water.

Once the housing is dismantled it may be found that the seals from between the face and the rest of the housing need to be replaced because they have warped, perished or deformed so that they cannot be effectively reused.

These seals are generally annular having a diameter of several inches (of the order of 20cm), and are therefore particularly susceptible to such wear.

Another disadvantage of using known fittings of the type having replaceable bulbs is that wires inside the light housing may become brittle due to the build up of heat in the housing during use, and may break during maintenance or bulb replacement. This necessitates drawing some of the cable attaching the light housing to the niche, into the housing in order to replace the damaged cable. Each time a length of cable is drawn into the housing for this reason, the remaining length of cable decreases and eventually there is insufficient cable left to allow the housing to be removed from the water. At this point replacement of the entire length of cable becomes necessary. This requires lowering the level of water in the pool below the level of the niche and considerable rewiring.

After bulb replacement the housing must be reassembled and it is vital to ensure that it is waterproof. There is therefore a tendency to over-tighten fixings in order to ensure a secure seal between the glass face and the rest of the housing, and this may damage the fixings, making subsequent bulb replacement still more difficult.

International Patent Application No WO 95/32388 discloses a light fitting which overcomes some of the above disadvantages. The replaceable bulb is mounted on a connection assembly which may be readily removed from the rear of the light fitting without complete dismantlement of the light fitting. A wet-mateable plug and socket connection is provided so that the

light fitting can be removed from the pool for maintenance, including changing the bulb. However the sealing required for the connection assembly makes such a light fitting expensive and there remains a need for a single use, sealed light fitting which can be replaced quickly and easily, but which is relatively cheap to manufacture.

According to the present invention there is provided an underwater light fitting comprising a housing, a bulb and a power supply cable; wherein said housing comprises a front cover and a rear cover sealingly connected to each other; wherein the front cover comprises a light transmissive lens portion and an integral surrounding flange portion, said surrounding flange portion being provided with mounting means for releasably mounting said light fitting into a niche provided in a wall or other surface; and wherein the rear cover comprises an entry means for said power supply cable to enter said housing, said entry means providing a watertight seal; said power supply cable having a wet-mateable connection at a first end outside said housing, the second end of said power supply cable extending inside said housing.

Preferably the fitting comprises two bulbs, mounted opposite each other. Preferably the fitting further comprises an electrical connection member inside said housing connected to the second end of said power supply cable, whereby two electrical cables each connect a respective bulb to said connection member.

Preferably said front cover and/or said rear cover are

made from a plastics material, most preferably produced by an injection moulding process.

Preferably said mounting means comprise a plurality of holes adapted to have a fixing means pass therethrough to secure said front cover to said wall or outer surface. Preferably said flange portion of the front cover extends beyond the extent of the rear cover.

Preferably, said front and rear covers include inter- engaging formations adapted to provide a snap-fit connection therebetween.

In one embodiment, the front cover is provided with a rearwards projecting web portion adapted to engage with a forwards projecting web portion provided on said rear cover. Preferably said web portions each comprise a portion of a substantially circular cylinder.

Preferably each of said web portions is provided with a detent portion at its free end adapted for mutual engagement.

In another embodiment, said inter-engaging formations comprise a plurality of hooked tongue portions formed on a peripheral flange portion of one of said front and rear covers and a corresponding plurality of slots formed in a peripheral flange portion of the other of said front and rear covers.

Preferably a sealing means is provided between the front cover and the rear cover. Preferably the sealing means comprises an O-ring seal. Preferably the sealing means is provided between said front and rear covers adjacent to said inter-engaging formations. Preferably the sealing means is adapted to be in a compressed

state when the inter-engaging formations are engaged.

Preferably, there is provided reflection means, intermediate the rear cover and front cover. According to one aspect the reflection means may be integral with said rear cover, and may be formed by applying a metallised coating to the material of the rear cover.

According to a preferred aspect the reflection means is a separate reflector of metal, preferably aluminium.

Preferably said reflector is provided with two apertures adapted to house said two bulbs.

Preferably, the light transmissive lens portion is a prismatic lens. Said lens may be provided with one or more prismatic portions extending around the perimeter of the lens.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig 1 is an exploded view of an underwater light fitting according to a first aspect of the present invention; Fig 2 shows a front elevation on the light fitting of Fig 1; Fig 3 shows a rear elevation on the light fitting of Fig 1; Fig 4 shows a side elevation on the light fitting of Fig 1; Fig 5 shows a sectional detail of the connection

between the front and rear covers of the light fitting of Fig 4; Fig 6 shows a schematic view of a light fitting according to the invention mounted in a niche; Fig 7 is an exploded view of an underwater light fitting according to a second aspect of the present invention; and Figs 8a to 8d illustrate a preferred embodiment of the connection between the front and rear covers of a light fitting in accordance with the invention.

With reference to Figs 1 to 6, an underwater light fitting comprises a housing generally designated 1, mounted in a niche 2 in the side wall 40 of a pool, and a power transmission cable 3 running from a wall of the niche 2. The power transmission cable 3 is provided with a wet-mateable connection 4, which mates with a corresponding connection 5 at the end of a cable 6 connected to the housing 1.

Wet-mateable connections, alternatively called underwater mateable connections, are known devices, often used in electrical cables when it is desirable to make and/or break connections underwater. Such connections typically comprise at least one pair of terminals to be connected, one of the pair being provided on a pin and the other being provided in a socket. Insertion of the pin into the socket makes the connection by bringing the pair of terminals into contact with each other. The close fit of the pin in the socket expels water from the vicinity of the

terminals. Such a connection can therefore be operated underwater, which in many circumstances is more convenient than making the connection in a dry environment, sealing it, and then moving it to the required, immersed location. Typically, such connections require the power to be disconnected while the pin is not inserted in the socket, since when this is the case, the terminals will not be isolated from the surrounding water.

The housing 1 is shown in an exploded manner in Fig 1 in order that the individual elements may easily be seen.

The housing 1 comprises a front cover 7 and a rear cover 8. A lens 10 is provided in the front cover 7.

Use of a selected lens 10 rather than a plain glass face allows the degree of dispersion of illumination into the water to be selectively predetermined (although a plain glass face could be used). The lens 10 is integral with the flange or bezel 11. In the bezel are provided a number of apertures 12, typically 6mm in diameter, by which the bezel 11 may be secured to the wall 40 of the pool using bolts or screws or other fastening means (not shown).

The housing 1 contains two bulbs 14 to provide illumination and a (preferably diffusing) reflector 15 to reflect illumination from the bulbs 14 towards the lens 10 at the front of the housing 1. The bulbs 14 are fitted in mounting blocks 16 which fit within apertures 17 in the reflector 15. The reflector is of such a size so that it fits securely inside the circumferential web 20 which projects from the rear face of the front cover 7.

For each bulb, a plug 18 is provided at the end of cable 19 to supply power to the mounting block 16 and bulb 14. The cables 19 are joined with the power supply cable 6 at a connection block 30. The supply cable 6 passes through the rear cover 8 at an aperture 33. Sealing plugs 31 and 32 fit around the cable 6 to ensure that water cannot enter through the aperture 33.

Access to the sealing plugs may be either from the outer face of the rear cover 8, as shown in Figs. 1 to 4, or alternatively from the inner face of the rear cover 8.

The front 7 and rear 8 covers snap together to form a sealed connection as shown in Fig. 5. Web 20 extends around an inner perimeter of the front cover 7 and is provided with a hook shaped detent portion 21 at its extremity. The perimeter of rear cover 8 is provided with a forwardly extending web 23, which is provided with a corresponding hook shaped detent portion 24 at its extremity. O-ring seal 22 is held between front cover 7 and web 23. If required, front cover 7 and web 23 can be formed with a slight recess to house the O- ring 22. Both webs 20 and 23 are resilient such that when the rear cover 8 is pressed onto the front cover 7, the detent portions 21,24 snap past each other, trapping the O-ring seal 22 between front cover 7 and web 23 therefore providing a watertight seal.

Figs. 8a to 8d illustrate an alternative, and preferred, embodiment of a snap fit connection between the front 7 and rear 8 covers. In this case, the rear cover 8 includes a peripheral flange 50 which extends parallel to the flange 11 of the front cover 7. The flange 11 is provided with a plurality of tongue members 51 extending rearwardly therefrom and spaced

around the periphery thereof as shown in Fig. 8b. The tongues 51 each have a hook shaped detent portion 52 at their extremities. The flange 50 is provided with a corresponding plurality of slots 53. The tongues 51 engage the slots 53 in a snap-fir manner as seen in Fig. 8d.

An 0-ring seal 22 is again held between the flanges 11 and 50 as seen in Figs. 8a and 8d, at a position radially inward from the tongues 51 and slots 53. The O-ring 22 is preferably located in an annular groove 54 formed in the surface of one of the flanges 11 and 50.

The flange 11 of the front cover 7 also includes slots 55 formed adjacent each tongue 51. These slots 55 are provided only to facilitate the formation of the tongues 51 by injection moulding or the like. The flange 50 of the rear cover 8 may also include upstanding wall portions 56 at least partially surrounding each of the slots 53, to protect the ends of the tongues 51 projecting therethrough.

Other means to seal front 7 and rear 8 covers may be used, for example sonic welding or solvent welding, in addition to or instead of those shown in Fig. 5 and described above. Since the lamp is designed to be a single use lamp, it is not anticipated that it will be necessary to separate the front and rear covers once they are sealingly joined.

Other arrangements of O-ring are possible. The O-ring 22 may alternatively be positioned between the web 20 and the rear cover 8 (not shown). The O-ring member may have a larger width, so that the inner diameter of the O-ring abuts against the outer wall of the web 20, while the outer diameter of the O-ring extends beyond

the outer wall of the web 23.

Two bulbs 14 are provided so that if one bulb should fail prematurely, the light fitting will remain operative. The fitting has to be replaced only when both bulbs have failed. In order to change the fitting, the housing 1 is removed from the water in which it is, in use, immersed by removing the mountings (screws or bolts or similar) which pass through the apertures 12 to secure the bezel 11 to the wall 40 around the niche 2. At this point it is still attached to the wall of the niche 2 by the power transmission cable 3,6. However, the housing 1 can be pulled a small distance out of the niche 2 and can then be detached from the rear wall of the niche 2 by separating the two elements 4,5 of the wet-mateable connector which is provided in the power transmission cable 3,6. The housing 1 is thus completely freed of its connection to the niche 2 and may be removed not only from the water but also from the vicinity of the pool in which it was installed. The whole housing is then discarded and a new housing attached to the cable 3 and socket 4, and secured in the niche by fastenings secured through the apertures 12.

Fig. 7 shows a second embodiment of the invention. The housing 1 comprises a front cover 7 and a rear cover 108. The front cover is identical to that described with reference to Figs. 1 to 6, so is not described further.

The rear cover 108 is formed with an integral reflector as one piece and contains two bulbs 114 to provide illumination. The reflector comprises the front face of the rear cover, which is moulded to the appropriate

shape and coated with a metallic or mirrored coating to provide a (preferably diffusing) reflector 115 to reflect illumination from the bulbs 114 towards the lens 10 at the front of the housing 1. The bulbs 114 are fitted in mounting blocks 116 which are integrally formed with the rear cover 108.

For each bulb, a cable 119 runs from a connection block 130 to the mounting block 116. The connection block 130 is connected to the power supply cable 6 at a connection block 130. The supply cable 6 passes through the rear cover 108 at an aperture 133. Sealing plugs 31 and 32 fit around the cable 6 to ensure that water cannot enter through the aperture 133.

The front 7 and rear 108 covers snap together as described previously with reference to Fig. 5.

The embodiments described above have many advantages over previously known underwater light fittings.

The wet-mateable connection 4,5 in the cable 3 enables the housing 1 to be easily disconnected from the niche 2. This means that replacement of the fitting is a simple exercise requiring a minimum of tools (normally a screwdriver or similar to undo the fastenings in the bezel). Alternatively the fastenings may be hand- operable (eg pus-fit fastenings), so that no tools are required. In addition the length of cable 6 needed for the disposable unit can be kept very short, while the permanent length of cable 3 is longer.

The simple watertight construction of the fitting means that water may circulate behind the fitting in the niche without risk of leakage into the housing 1. This

allows greater circulation of water in the niche 2, enhancing the cooling of the housing 1. This prolongs the life of components in the housing 1, such as the cable 3 and the bulb 14, and may allow less specialised, cheaper bulbs to be used.

The cable between the niche wall and the wet-mateable connector is not damaged by normal operation of the light fitting and therefore does not need to be routinely replaced. This avoids the need for the expensive and time consuming operation of draining the pool.

Underwater light fittings according to the present invention may be suitable for many uses in addition to swimming pool and spa bath use. For example, such fittings may be used in beer vats or in the hulls of boats or in many other circumstances where niche mounted underwater light fittings are required.

Many alternative embodiments can be envisaged, without departing from the scope of the invention, which is to indicated by the appended claims rather than by the foregoing description. For example the front cover may have a spray coating on the bezel portion to give the visual effect of a metallic bezel. The bezel portion may be frosted or coloured, or the whole front cover may be frosted to provide a diffuse light. The material of the front cover and lens is preferably polycarbonate or Noril (TM), although other suitable materials may be used, providing they offer the required properties of water resistance, chemical resistance, mouldability and strength. The material of the rear cover is preferably poly phenylene ether, although other suitable materials may be used,

providing they offer the required properties of water resistance, heat resistance, chemical resistance, mouldability, resilience and strength, and in the case of the rear cover with integral reflector the ability to have metal deposited thereon.

Although the illustrated embodiments show two bulbs, the invention may be provided with only one bulb 14, one connector 16, one plug 18 and one cable 19. The bulb 14 may be connected to the cable by other suitable connection means, eg soldering, direct clamping of the cable to the bulb terminals etc.

These and other modifications and improvements can be incorporated without departing from the scope of the invention.