WO1999017054A1

WO1999017054A1 - Safety housing for a light tube

Info

Publication number: WO1999017054A1
Application number: PCT/AU1998/000802
Authority: WO
Inventors: David Field Showers; Malcolm Wesley Oldis; Kenneth Robert Goddard
Original assignee: Showers International Pty. Ltd.
Priority date: 1997-09-26
Filing date: 1998-09-25
Publication date: 1999-04-08
Also published as: AUPO950197A0

Abstract

A safety housing for one or more light tubes, or light arrays, including an elongate main housing body (22) having a longitudinally extending base (23), a pair of end walls (30, 32) and a longitudinally extending side walls (24a, 24b). A translucent cover (25) is engageable with the housing body and co-operable with the side walls and end walls to define a substantially closed space (15) for retaining at least one light tube or light array behind the cover. Means to provide access to said space includes an element (73) detachably mounted to the housing and coupled to the cover for detachment therewith to allow removal and replacement of the light tube or array.

Description

SAFETY HOUSING FOR A LIGHT TUBE

Field of the Invention

This invention relates to an improved safety housing, especially for an elongate light means. The invention is described herein primarily in relation to light tube housings, especially housings for fluorescent tubes, but is of course not so limited in scope. The invention is also described in relation to a housing suitable for under-counter installation but is also not limited to that application.

Background Art

It is common practice to install fluorescent tubes in ceilings or at ceiling height. The housings for these tubes are typically relatively open, for example comprising a grid-like diffuser and exposed sockets that enable easy release of the tubes. However, because of their height, the tube and electrical components are not readily accessible without the use of a ladder and so the exposed fittings do not present a significant safety risk. The safety aspects of light tube housings have to be more carefully considered when they are installed, for example, at counter level or eye level. Generally, light housings installed at this lower level have remained essentially the same as those commonly installed in ceilings.

Especially in publicly accessible premises, these conventional housings can be a hazard to the general public : in some instances, small children can easily touch electrical components and the light tube, or wiring and components can easily become exposed. Any effort to address this problem should take account of the separate need to achieve compactness in the context of an under-counter installation.

It is therefore an object of the invention to address one or more of the problems identified above.

A further object of the invention, at least in one or more preferred embodiments, is to provide a compact, relatively tamper-proof housing for light tubes or light arrays that can be installed with minimal safety risks in a location exposed to public contact.

It is a further object, at least in one or more preferred embodiments, to provide a safety housing for light tubes or light arrays that can be mounted as one of a series of housings in a modular system.

Summary of the Invention

In a first aspect, the invention accordingly provides a safety housing for one or more light tubes or light arrays, including:

an elongate main housing body having a longitudinally extending base, a pair of end walls, and longitudinally extending side walls;

a translucent cover engageable with the housing body and co-operable with the side walls and end walls to define a substantially closed space for retaining a light tube or light array behind the cover, said space also preferably retaining electrical componentary associated with the tube or array; and

means to provide access to said space comprising an element detachably mounted to the housing and coupled to the cover for detachment therewith to allow removal and replacement of the light tube or array.

Preferably said element comprises an end plate forming all or part of one of said end walls of the housing.

In a particularly preferred embodiment, said element is a portion of one of the end walls, forming a first plate, and the remaining portion of the end plate forms a second plate which, when removed, allows access to electrical components associated with the light tube or light array.

Advantageously the first plate is associated with means to disconnect the power supply to the tube or array when it is detached, which means may comprise a microswitch within the housing in contact with the first plate. In a preferred embodiment, access to the electrical componentary is only possible by first removing the first plate and then removing the second plate.

The element may alternatively comprise a bracket that fits over a portion of the cover and a wall of the housing, detachably securing them together. A microswitch or similar device may be provided for disconnecting the power supply when the bracket is detached from one or both of the cover and housing wall.

Preferably the cover portion is a translucent perspex or similar material. It may be transparent and/or coloured. Light tube sockets may be provided on support means removably mounted in the main housing body. The main housing body preferably includes means for mounting such a support, e.g. opposed grooves in which the support may be slidably fitted.

Preferably the safety housing is adapted to be detachably fitted to a mounting rail, or array of rail segments or brackets, for example as one of a plurality of similar housings of a modular system for supporting a plurality of light tubes in a linear array. In one embodiment the end walls of the housing have electrical plug/socket connections for electrical coupling to an adjacent housing: this allows electrical power to be delivered through a modular series of housings without any electrical power supply in the mounting rail. There is no potentially "live" rail in fixed position. The second plate may have one or more lugs that latch with an end plate of an adjacent light fitting when they are connected end-to-end.

In a particularly preferred embodiment, the main housing body comprises a channel wherein the side walls of the channel have substantially parallel portions nearer the base of the channel, and respective opposed mutually divergent portions further from the base defining an opening from the housing body which is closed by the cover, and the housing further includes means for mounting a light tube or light array at two or more transversely spaced positions within the housing which are at different distances from the cover and in which the light tube or light array extends generally longitudinally of the housing.

In a second aspect the invention provides a channel housing for one or more light tubes or light arrays, including a longitudinally extending base and a pair of longitudinally extending side walls, wherein, in transverse cross-section, said side walls have respective opposed substantially parallel portions nearer the base, and respective opposed mutually divergent portions further from the base defining an opening from the housing, and wherein said housing further includes means for mounting a light tube or light array at two or more transversely spaced positions which are at different distances from the cover and in which the light tube or light array extends generally longitudinally of the housing.

In a preferred embodiment, all or part of the interior surface of the channel housing, e.g. the divergent portions, is light reflective. Advantageously, the characteristics of the beam exiting the housing though the opening can be modified by varying the transverse position of the tube or array within the housing. To achieve this there may be provided, within the housing, at least two pairs of opposed grooves adapted to receive support means for the tube or array. These grooves may also be adapted, at least at their ends, to receive screws.

In both aspects of the invention, the light tube may be a fluorescent or incandescent tube. The light array may be an array of incandescent lamps or light emitting diode (LED) devices.

Preferably, the housing is extruded and can therefore be manufactured to suit any length light installation.

The housing may include near its opening an additional pair of opposed grooves adapted to receive a translucent cover. In a preferred embodiment the housing has, on the external surface of the base, a pair of rails that are adapted to engage a mounting rail. Preferably the mounting rail is extruded and is adapted to be fixed to a structure.

Brief Description of the Drawings

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an isometric view of the essential components of a modular system for undercounter mounting of fluorescent tubes, showing the mounting rail and one safety housing module;

Figure 2 is a transverse cross section on the line 2-2 on Figure 1 ; Figure 3 is an exploded isometric view at the access end of the housing; and

Figure 4 depicts the fixing end of the housing.

Preferred Embodiments

The illustrated modular undercounter mounting system 10 for fluorescent light tubes includes an extended mounting rail 12 and multiple similar safety housing modules 20. These modules 20 may vary in size to suit particular lengths of tube and particular numbers of tubes, but this embodiment is adapted for a single tube.

Module 20 has an elongate main housing body in the form of an extruded aluminium channel 22, and a translucent, indeed in this case transparent, cover 25 that slidably engages respective opposed integral grooves 27 in beads 26 at the mouth 21 of the channel. Channel 22 has a longitudinally extending flat base 23, longitudinal side walls 24a,24b, and respective end wall structures 30,32, to be described further below. Slidable cover 25 co-operates with side walls 24a,24b to define a substantially closed space 15 for retaining a fluorescent light tube 8 and electrical componentary therefor. Cover 25 may of course be coloured and/or opaque.

Side walls 24a,24b are each formed in two portions - inner opposed parallel portions 40, 41 adjacent base 23, and outer opposed mutually divergent portions 42, 43 defining the mouth or opening 21 of the channel and across which cover 25 is slidably located. Side wall portions 40, 41 are formed internally with opposed hollow beads or rails 50 which define respective opposed pairs of grooves 52a, 52b, 52c. The centre pair 52b is for slidably mounting a support strip 19. Support strip 19 carries conventional end sockets 54 for mounting the fluorescent tube and includes printed conductors for delivering electrical current to the end sockets and therefore to the tubes.

The uppermost and lowermost of grooves 52, i.e. grooves 52a,52c, are of tubular form and include threading at their ends to receive screws for fixing end wall structures 30, 32.

The other necessary electrical components 60 for operating the fluorescent tube, including the power supply, starter, ballast and the like, are collectively disposed and mounted adjacent end wall structure 30, to the underside of support strip 19 in the compartment of space 15 between the strip and housing base 23.

Wires, not shown, link these components to the conductors of mounting strip 19.

Mounting rail 12 is a uniform aluminium extrusion comprising similar side flanges 13 linked by a longitudinally extending web 14. The rear edges at one side of flanges 13 are formed with internal beads 16 and abut a wall surface 7 to which the rail is to be mounted. Web 14 is offset behind the front edges of the flanges and has a first set of smaller apertures 14a through which fasteners may be fitted to secure the rail to wall surface 7.

Web 14 and the adjacent outer shorter portions of flanges 13 define a shallow channel 17 which receives shallow parallel ribs 60 (Figure 2) on the outside face of housing base 23, in a close fit. Each module is fastened to the rail by means of end wall assembly 32, which consists of an end plate 33 with a central tab 34 (Figure 4) by which the plate is secured to a set of larger apertures 14b in web 14 by any suitable fastener 70 not requiring access from the rear, for example a rotatable ramp-action toggle or the like. End wall 33 of end wall assembly 32 is fastened to one end of module 20 by means of four screws engaged in the threaded ends of grooves 52a,52c.

The other end wall assembly 30 is a dual plate structure for providing access to the space 15, and is held down by a pair of projecting lugs 71 which lie under the bottom edge 35 of the end wall assembly 32 of the next adjacent module. This arrangement has the additional advantage that the fastening at tab 34 lies under a module. These lugs 71 are provided on the lower plate 72 of a pair of complementary coplanar plates 72, 73 which close over the respective end of module 20. Upper plate 73 is fastened by screws to upper mounting grooves 52a and has an upper inwardly directed flange 74 that is secured by pop rivets or similar to an end of cover 25. Lower plate 72, whose upper edge abuts or lies adjacent to upper plate 73, is fastened to the lower mounting grooves 52c and has further inwardly located screws by which the plate carries behind it an upstanding panel 75 (Figure 3). Panel 75 is in turn welded or otherwise secured to the end edge of slidable support strip 19. Panel 75 is spaced from lower plate 72 and projects up behind plate 73 to carry a micro-switch 76 which is arranged to be closed when plate 73 is engaged fully home against the end of housing channel 22. When plate 73 is unfastened and withdrawn, micro-switch 76 is opened to shut off power to the tube and electrical componentary.

End wall assemblies 30,32 include complementary electrical plug/socket units 80,82 for electrically coupling each module to the next adjacent module or to an external power supply cable. This configuration allows the electrical power supply to come with the modules, and to be delivered through the line of mounted modules, rather than via cables and contacts on the mounting rails. The latter approach is the more conventional with lighting track systems, but the consequence is that there is a potentially "live" mounting rail permanently installed.

It will be understood that a failed fluorescent tube can be replaced by withdrawing the modules in turn until the problem module is accessed and detached from the backing rail. Upper access plate 73 is then disengaged from channel housing 22 and the cover 25 slidably withdrawn from the housing to provide access to the tube for its removal and replacement. Importantly for safety, there can be no power supplied to the tube during this operation because of the disabling of micro-switch 76. Where there is problem with the other electrical components of the fitting, the further screws can be removed to detach lower access plate 72 so as permit withdrawal of support strip 19 and access to components on this strip or on the channel base. It will be appreciated that this second access operation cannot be performed without first removing plate 73 to disable the power supply.

It will also be understood that, in other possible embodiments, cover 25 may be withdrawn laterally rather than longitudinally and the access structure may be disposed in a side of the channel rather than at one end. Such an arrangement would have the advantage of allowing servicing of a module in a row of modules without any need to remove others in the row.

The illustrated arrangement is particularly suitable for mounting fluorescent tubes or other light tubes in locations such as under counters or in display arrangements at body height. The tube is safely retained in an enclosure in which mounting sockets and electrical components cannot normally be touched. The system is modular for providing linear arrays of tubes and the fixing of each module is simply and effectively performed. The access arrangements for the servicing or replacement of tubes or associated components do not permit idle tampering and provide power disengagement as a built-in feature.

In other applications, instead of tube 8, there may be an array of separate lamps or LED devices, eg. mounted on a supporting length of PCB (printed circuit board) strip.

It will be understood that rail 12 need not be a continuous element.

Modules 20 might instead be attached to spaced rail segments or brackets.

The characteristics of the beam exiting the housing though the opening can be modified by varying the transverse position of the tube within the housing. The different positions are defined by the respective sets of grooves 52a,52b,52c. Further effects are obtainable by making the internal surface of channel 22 reflective, or by varying its reflectivity.

Claims

1. A safety housing for one or more light tubes, or light arrays, including:- an elongate main housing body having a longitudinally extending base, a pair of end walls, and longitudinally extending side walls; a translucent cover engageable with the housing body and co-operable with the side walls and end walls to define a substantially closed space for retaining at least one light tube or light array behind the cover; and means to provide access to said space including an element detachably mounted to the housing and coupled to the cover for detachment therewith to allow removal and replacement of the light tube or array.

2. A safety housing according to claim 1 wherein said element comprises an end plate forming all or part of one of said end walls of the housing.

3. A safety housing according to claim 1 wherein said element is a portion of one of the end walls, forming a first plate, and the remaining portion of the end plate forms a second plate which, when removed, allows access to electrical components associated with the light tube or light array.

4. A safety housing according to claim 3 wherein said first plate is associated with means to disconnect the power supply to the tube or array when it is detached.

5. A safety housing according to any preceding claim wherein said space retains electrical componentary associated with the tube.

6. A safety housing according to claim 3 or 4 and 5 wherein access to said electrical componentary is only possible by first removing the first plate and then removing the second plate.

7. A safety housing according to claim 1 or 2 wherein said element includes a bracket that fits over a portion of the cover and a wall of the housing, detachably securing them together.

8. A safety housing according to any preceding claim, further including a microswitch or similar device arranged for disconnecting the power supply when the bracket is detached from one or both of the cover and housing wall.

9. A safety housing according to any preceding claim where said cover is of a translucent material.

10. A safety housing according to any preceding claim, further including light tube sockets on support means removably mounted in the main housing body.

11. A safety housing according to any preceding claim, wherein said safety housing is adapted to be detachably fitted to a mounting rail, or array of rail segments or brackets, for example as one of a plurality of similar housings of a modular system for supporting a plurality of light tubes in a linear array.

12. A safety housing according to claim 11 wherein said housings have external electrical connections for electrical coupling to an adjacent housing, whereby electrical power for said light tubes or light arrays may be delivered via the housings without recourse to any power supply in said mounting rail.

13. A safety housing according to any preceding claim, wherein said main housing body comprises a channel wherein the side walls of the channel have substantially parallel portions nearer the base of the channel, and respective opposed mutually divergent portions further from the base defining an opening from the housing body which is closed by the cover, and the housing further includes means for mounting a light tube or light array at two or more transversely spaced positions within the housing which are at different distances from the cover and in which the light tube or light array extends generally longitudinally of the housing.

14. A channel housing for one or more light tubes or light arrays, including a longitudinally extending base and a pair of longitudinally extending side walls, wherein, in transverse cross-section, said side walls have respective opposed substantially parallel portions nearer the base, and respective opposed mutually divergent portions further from the base defining an opening from the housing, and wherein said housing further includes means for mounting a light tube or light array at two or more transversely spaced positions which are at different distances from the cover and in which the light tube or light array extends generally longitudinally of the housing.

15. A channel housing according to claim 14, wherein all or part of the interior surface of the channel housing, e.g. the divergent portions, is light reflective.

16. A channel housing according to claim 15, adapted for modifying the characteristics of the beam exiting the housing through the opening by varying the transverse position of the tube or array within the housing.