ELECTRICAL UNIT FOR SUSPENDED CEILING

Abstract: A transformer unit (1) for a suspended ceiling has a cup-shaped housing in the base of which are formed two grooves (3, 4). These grooves correspond to longitudinal members (6, 7) of the ceiling frame and enable the transformer to be mounted securely on the frame in the vicinity of the lights (11).

Description: ELECTRICA UNIT FOR SUSPENDED CEILING The invention concerns an electrical unit, in particular a transformer, for use in indoor lighting systems, and a suspended ceiling assembly including such a unit. Many modern and modernised buildings have false ceilings suspended from the structural ceiling, enabling cabling and other supply facilities to be kept out of sight above the ceiling. The ceiling itself is usually made of a steel frame suspended from the structural ceiling by suitably distributed support wires; panels of, for instance, mineral-fibre-based material are then inserted so as to rest in the frame, providing the ceiling cover. The panels are generally rectangular, of standard sizes such as 40 x 40 cm or 40 x 80 cm. In such a ceiling the lighting is generally provided by specialised matching panels containing light fittings, which may include fluorescent lamps or incandescent lamps. One kind of light fitting often used is the halogen lamp. These lamps generally require a 12V DC source to be generated from the mains supply. The halogen lamps, which are light in weight, are fitted in the centre of an otherwise plain panel of fibrous material which supports them. In order to provide the 12V supply it is necessary to include a transformer in the system. Since a suitable transformer might weigh about 1 kg it cannot be integrated with the light fitting itself without the use of additional suspension means and is therefore usually mounted on the structural ceiling or a wall, possibly several metres from the light. Typically one transformer will be used for several, perhaps ten, individual lamps. Wires then extend from the transformer to the lamps, suitably rectified to provide the DC supply. One problem with this arrangement is that there is a voltage drop from the transformer to each light fitting; further, the drop is different for lights at different distances from the transformer, unless redundant wiring is used. In any case it is inconvenient and complicates fitting either to have the transformers spaced so far from the lights they serve or to have to provide additional supports for the transformers to mount them near the lights. According to one aspect of the invention there is provided an electrical unit, in particular a transformer unit, for use in electrical installations in suspended ceilings, characterised in that the unit includes means for engaging the frame of the suspended ceiling so that the unit may be supported by the frame. Preferably the unit includes a generally cup- shaped housing containing the transformer or other component, and the housing itself forms the engagement means. Preferably the housing has a groove on the underside constituting the engaging means and corresponding to a longitudinal member of the ceiling frame. For stability the cup should be mounted on an intersection of the longitudinal frame members and in this case there should be two intersecting grooves corresponding to the intersection of the ceiling members. In standard ceilings the longitudinal members, and therefore the grooves, will intersect at right angles. Alternatively the transformer may itself be so shaped as to engage the ceiling frame. The transformer housing is preferably made of an electrically insulating material, such as PVC or ABS ( a styrene-based plastics material), and the mounting of the transformer in it is advantageously carried out by placing the transformer in the cup and pouring thermosetting resin over it so as to encapsulate the transformer within the cup. The assembly may then be seal with a lid and provided with a socket for detachable light fittings. In another aspect the invention is directed to a ceiling assembly comprising a suspended frame, a light mounted in the frame and an electrical unit connected to the light, wherein the electrical unit is mounted on the suspended frame. For a better understanding of the invention an embodiment will now be described with reference to the accompanying drawings, in which Fig. 1 shows a transformer unit and part of the ceiling frame, and Fig. 2 shows schematically the assembly of such a unit into a ceiling. A transformer casing 1 is of a generally circular cup shape except for perpendicularly intersecting grooves 3,4 in its base. The grooves have a slightly greater width than the intersecting longitudinal members 6, 7 of the ceiling frame so that the cup 1 can be placed on the intersection and is then firmly in position, secured against horizontal movement. In use, as shown in Fig. 2, at least one light panel 10 adjacent to the intersection shown is inserted into one of the square or rectangular spaces defined by the frame, resting on the flanges 8. The transformer is then placed on the intersection and connected by a lead 12 to the light 11. As can be seen, the transformer rests on the frame above the level of the panels, and the distance from the transformer to the light (or lights) is small. This facilitates assembly and reduces the voltage drop between transformer and lamp. A single transformer can advantageously be used to provide power for two lamps in adjacent or at any rate closely spaced panels. The circular cup shown is particularly suitable for toroidal transformers, but clearly cups of different shapes may be chosen as appropriate provided that the grooves in the base match the ceiling framework. The rating of the transformers might be 80VA or 110VA, having weights 900g and 1350g respectively, both fitting in a casing of height 6cm and diameter 10cm. The 80VA transformer is suitable for supplying two 35W lamps or one 50W lamp, and the 110VA transformer would be sufficient for two 50W lamps. The lamps themselves may be 12V dichroic or capsule lamps. Clearly the invention is not restricted to rectangular ceiling framworks but could be used, if the circumstances so dictated, for hexagonal or even irregular frameworks. Likewise the grooves shown for engaging with the suspended ceiling represent a particularly simple and effective arrangement, but other engagement means could be envisaged, such as clips or magnetic holders.

Claims: CLAIMS : 1. An electrical unit, in particular a transformer unit, for use in electrical installations in suspended ceilings, characterised in that the unit includes means for engaging the frame of the suspended ceiling so that the unit may be supported by the frame. 2. An electrical unit according to claim 1, in which the unit includes a generally cup-shaped housing containing the transformer or other component. 3. An electrical unit according to claim 2, in which the housing has a groove on the underside constituting the engaging means and corresponding to a longitudinal member of the ceiling frame. 4. An electrical unit according to claim 3, and having two such grooves arranged in an intersecting manner so as to correspond with an intersection of the two ceiling members. 5. A ceiling assembly comprising a suspended frame, an electrical appliance mounted in the frame and an electrical unit connected to the appliance, characterised in that the electrical unit is mounted on the suspended frame. 6. A ceiling assembly according to claim 5 and including two or more appliances connected to the electrical unit. 7. A ceiling assembly according to claim 5 or 6, wherein the electrical appliances are halogen lights.

Inventors: RAY PETER, RAY, PETER
Applicants: YORKLITE LTD, YORKLITE LIMITED
Application year: 1991
Main classification: H05B39
IPC codes: F21V23, H05B39