Fluorescent light fitting and system

Abstract: A fluorescent light fitting (1) comprises an elongate metal casing (2) of hollow cross-section with spaced-apart fluorescent tube holders (6) projecting from at least one wall (5) of the casing (2) and with another wall (4) of the casing provided with a removable or releasable baseplate (14) on which internal electrical components (13) are mounted, with means (18, 19, 2⊘) to fasten the baseplate (14) to the fitting (1).

Description: This invention relates to a fluorescent light fitting and system particularly though not exclusively for workplace, factory or office use. The economic benefits derived from the use of fluorescent tubes are well known but conventional elongate metallic casings, suspended from or screwed to ceilings or walls, present an access problem for service or repair in that before the internal electrical components, e.g. a choke condenser, starter etc., i.e. the so-called running gear, can be reached it is necessary to remove the fluorescent tube, its reflector and a cover plate before access is possible to the internal components. Furthermore, the cover plate, relector and tube must all be replaced before the repaired or serviced components can be tested. This is a tedious and normally two-man operation as the fittings are usually at inconvenient locations, e.g. overhead. In US 3,594,568 is disclosed a fluorescent light fitting provided with a releasable baseplate on which internal electrical components are mounted. Whilst providing ready access to those components for servicing, repair or replacement, these operations are almost inevitably at an inconvenient, overhead location. In GB 576,852 is disclosed a fluorescent light fitting in which electrical components expected to require servicing, repair or replacement are located externally of the fitting, with a sheet metal casing covering the components. To remove the casing at least one screw must be released. To remove a baseplate to which the components are attached by screwed down straps, multiple numbers of screws must be released - all usually from an overhead location - with reverse of this procedure to re-fit the baseplate and casing. According to a first aspect of the present invention, there is provided a fluorescent light fitting comprising an elongate metal casing of hollow cross-section, with spaced-apart fluorescent tube holders projecting from an external surface of the casing, the casing comprises an upper wall and a lower wall spaced from the upper wall by a pair of downwardly inclined sidewalls and with the lower wall of the casing provided with a removable or releasable baseplate on which internal electrical components are mounted, with means to fasten and release the baseplate to its wall, with said components normally located internally of the casing, when the baseplate is in its fastened position, and with the components temporarily exposed for servicing when the baseplate is released, characterised in that with holders projecting laterally of the casing from each sidewall, with the holders downwardly inclined and with the components carried indirectly by the baseplate, being mounted on an exchangeable support or gear tray which is in turn releasably attached to the baseplate. Thus, with the fitting construction in accordance with the invention, servicing and/or repair of the internal electrical components can be effected without the need to remove and subsequently replace, the reflector and fluorescent tube, while a failed or faulty fitting can be rapidly restored to service by a gear tray exchange, with suitable wiring disconnections and re-connections, which are preferably hard wiring connections, and with the faulty gear tray examined and repaired either on site or at a later date in a workshop with full test facilities. Furthermore, the means to fasten/release the baseplate to its wall is preferably of a single screw or a quick-release type, e.g. a winged stud rotatable through 90° between fastening and non-fastening positions to engage a suitable aperture e.g. of a slotted hole. In detail, such aperture may be at one end or side of the baseplate, with the stud captivated to the fitting, while the other end or side of the baseplate may be provided with a projecting tongue to engage over an inner portion of the casing. By such an arrangement removal of the baseplate can be a one-handed and hence one man operation. In an alternative construction, the other end or side of the baseplate may be hinged to the casing, to provide a drop-down releasable baseplate, in contrast to a totally removable baseplate. The releasable attachment of the removable gear tray is again of a quick-release type, such as 90° rotatable winged studs or screw and bush on stud and nut and suitably slotted apertures, again to provide for one man operation. In detail, the fitting comprises an upper wall, e.g. adapted to be secured to a ceiling, roof, walls, standard trunking etc., by standard fixing methods, and a lower, parallel wall spaced from the upper wall by a pair of side walls, with holders for fluorescent tubes carried by each sidewall, with one, but preferably both sidewall carrying a single tube or multiple tubes. Preferably, the casing is formed as an integral pressing from sheet metal. The sidewalls are preferably angled downwardly to define an acute angle. Each casing is preferably of a unit length convenient for handling/transport/storage, e.g. of 1, 2 or more metres length. Each casing may terminate in an end wall, by the use of which adjacent ends of adjacent casings may be butted and secured together, e.g. by the use of screws. In an alternative construction, a spigot and socket type connection may be used between adjacent ends of adjacent casings, either by slightly enlarging one end of each casing, or by the use of a coupling sleeve common to both casing ends, and clearly some fastening means, e.g. a screw, is required. It is also conventional practice to provide a batten and trunking to convey power to fluorescent fittings, this being a more or less permanent fixture and, if located wrongly, or if a change in light fitting position is required, needs to be dismantled and re-located. According to another preferred feature, the casing also houses at least one electrical power supply conductor or bus-bar extending the full length, or substantially the full length, of the casing, whereby a plurality of casings may be located together end-to-end, with the power supply conductor(s) or bus-bar(s) of adjacent casings electrically connected together. According to a second aspect of the present invention, of independent significance, there is provided a lighting system comprising a plurality of elongate metal casings in accordance with the first aspect of the invention and incorporating the feature of the preceding paragraph secured together end-to-end, and adapted to be supported from, or secured to, a ceiling/roof, or secured to a wall. The system in accordance with the second aspect of the invention advantageously provides a system with self-contained or integrated power supply trunking/cabling/bus-bars. The casing is preferably of elongate hollow section, with a plurality of such casings adapted to be located end-to-end, along a production line for example. Preferably, the or each casing is provided with end walls having apertures, e.g. three, for entry and exit of conductors/cables at each end of the casing. For this end-to-end connection, the apertures are preferably provided with industry-standard cable glands, with the conductors/cables looped through the casings during installation. If a flexible or semi-flexible conductor, e.g. insulated cables, is or are employed, then preferably these conductors/cables are positionally controlled by a cable retaining hoop, or series of hoops along the casing, to obviate the conductors/cable(s) sagging or coming into close proximity, or contact, with the running gear. Such a hoop or hoop system is of course unnecessary if the conductor(s) is in the form of a rigid bus-bar. In addition, the interior of the casing may be so dimensioned as to be capable of accommodating and routing non-related services. It will be appreciated that if the first aspect of the invention is incorporated into the second aspect of the invention, then the removable or releasable cover plate also provides ready access to the conductors/cables or bus-bars for connection, servicing or repair thereof. Examples of the fitting in accordance with the first aspect of the invention, and the system in accordance with the second aspect of the invention, are shown in the accompanying drawings, in which:- Figure 1 is a diagrammatic side elevation of a fitting in accordance with the first aspect of the invention; Figure 2 is a diagrammatic end elevation of the fitting of Figure 1 to a larger scale; Figure 3 shows diagrammatically a lighting system in accordance with the second aspect of the invention, with one casing sidewall removed for clarity; and Figure 4 is an underneath plan view in the direction of arrow A of Figure 3. In the drawings, a fluorescent light fitting 1 comprises an elongate hollow metal casing 2 of unit length, pressed from sheet metal. The casing 2 comprises an upper wall 3 adapted to be secured to, or suspended from, a ceiling, or to be secured to a wall or other support structure, and having a lower, parallel wall 4 spaced from the upper wall 3 by a pair of sidewalls 5 which are angled downwardly as indicated in Figure 2, with each sidewall 5 carrying a pair of spaced apart holders 6 to receive opposite ends of a fluorescent tube 7, with a reflector 8 extending the length of the casing/tube and also secured to each sidewall 5. Also as best indicated in Figure 2, each casing 2 terminates in an endwall 9 having three apertures 10 for entry of insulated conductor cables 11 at one end of the casing, and exit of cables from the other end of the casing, with the cables looped through the casing and positionally controlled by a series of hoops 12 along the casing. The tubes 7 are powered via industry-standard components 13, known as "running gear" located internally of the casing, and in accordance with the first aspect of the invention, the components 13 are mounted on a readily removable or releasable base plate 14 shown at the right hand side of Figure 1 in its closed, active position, and at the left hand side of Figure 1 in its released, open position for servicing, repair, etc., the components 13 of one base plate being for powering the tube(s) 7 of one sidewall 5, and the components 13 of the other base plate being for powering the tube(s) 7 of the other sidewall 5. Each baseplate 14 is oblong and serves, in its closed position, to close off a correspondingly oblong slot 15 provided in the lower wall 4, towards each opposite end of the casing, and each baseplate 14 is provided at one end with a tongue 16 to seat on inner portion 17 of the lower wall 4, and at its other end with a pair of laterally spaced-apart slotted apertures 18, each to receive a wing 19 of a stud 20 captivated to the lower wall 4 of the casing and rotatable through 90° between fastening and non-fastening positions. In detail, the components 13 are mounted indirectly on the baseplate 14, via a tray 21 which is readily removable and replaceable by means of a similar quick-release fastening means in the form of winged studs 22 rotatable through 90° between fastening and non-fastening positions captivated either to the tray or to the baseplate and adapted to penetrate slotted apertures in the other. The second aspect of the invention is illustrated in Figures 3 and 4. Endwalls 9 of adjacent casings 2 are butted together and secured by metallic glands 23 e.g. of brass, which are screwed together, whereby each casing 2 provides a self-contained conduit for cables 11, bus-bars or trunking, with attendant advantages discussed earlier. Also, as detailed in Figures 3 and 4, the three insulated cables 11 (being live, neutral and earth) are each connected to a terminal block 24 secured, e.g. by adhesive, to the inside of the upper wall 2, and to each terminal block 24 is also secured one of three fly wires 25 bridging the butted walls 9 and extending to three similar terminal blocks 24 in the adjacent casing 2. Clearly, additional terminal blocks 24 may be provided for additional sets of cables 11.

Claims: A fluorescent light fitting (1) comprising an elongate metal casing (2) of hollow cross-section, with spaced-apart fluorescent tube holders (7) projecting from an external surface of the casing (2), the casing comprising an upper wall (3) and a lower wall (4) spaced from the upper wall (3) by a pair of downwardly inclined sidewalls (5) and with the lower wall (4) of the casing (2) provided with a removable or releasable baseplate (14) on which internal electrical components (13) are mounted, with means (18, 19, 20) to fasten and release the baseplate (14) to its wall (4), with said components (13) normally located internally of the casing (2), when the baseplate (14) is in its fastened position, and with the components (13) temporarily exposed for servicing when the baseplate is released, characterised in that the said holders (7) project laterally of the casing (2) from each sidewall (5), with the said holders (7) downwardly inclined, and in that the said components (13) are carried indirectly by the baseplate (14), the components (13) being mounted on an exchangeable support or gear tray (21) which is in turn releasably attached to the baseplate (14). A fitting as claimed in Claim 1, characterised in that the fastening means (18, 19, 20) comprise a winged stud (19, 20) rotatable through 90° between fastening and non-fastening positions to engage a suitable aperture (18). A fitting as claimed in Claim 1 or Claim 2, characterised in that one end of the baseplate (14) is provided with a projecting tongue (16) to engage over an innner portion (17) of the casing (2). A fitting as claimed in Claim 3, characterised in that the other end of the baseplate (14) is hinged to the casing (2), to provide a drop-down, releasable baseplate (14). A fluorescent light fitting as claimed in any preceding claim characterised in that the casing (2) houses at least one electrical power supply conductor (11) or bus-bar extending the full length, or substantially the full length, of the casing (2), whereby a plurality of casings (2) are locatable together end-to-end, with the power supply conductor(s) (11) or bus-bar(s) of adjacent casings (2) electrically connected together. A fitting as claimed in Claim 5, characterised in that the casing (2) is provided with end walls (9) having apertures (10) for entry and exit of conductors (11) at each end of the casing (2). A fitting as claimed in Claim 6, characterised in that the apertures (10) are provided with cable glands (23), with the conductors (11) looped through the casings (2) during installation. A lighting system comprising a plurality of fittings (1) as defined in Claims 5 to 7, with their casings (2) butted and secured together end-to-end.

Inventors: DAVIES JOHN HOWARD, DAVIES, JOHN HOWARD
Applicants: FIFTH GENERATION TECHNOLOGY, FIFTH GENERATION TECHNOLOGY (MANUFACTURING) LTD
Application year: 1989
Main classification: F21S3
IPC codes: F21V23, F21S8, F21V21