GB2183322A - Pole-mounted luminaire - Google Patents

Abstract

A luminaire having a canopy (12) and transparent cover (14) together defining an enclosure accommodating a light source (28) is mounted on the end of a supporting pole (30) by means disposed overlying part of the light-emitting portion of the luminaire and comprising a straight-sectioned U-bolt (46) or the like whose legs (49) pass around the pole end and through respective bores (50) in an integral wall (36) of the canopy into the enclosure where nuts (56) are tightened to clamp the wall (36) against the pole end. Seals (57) are provided in the bore (50) which are compressed upon tightening of the nuts (56) to seal around the legs and prevent the ingress of water and dust. The arrangement provides a compact well-sealed, luminaire capable of being mounted on differently-sized poles. <IMAGE>

Description

SPECIFICATION Luminaires This invention relates to a luminaire comprising a moulded canopy and a lighttransparent coverjoined tothecanopywhichtogetherdefinean enclosure in which a light source is accomodated, and means for mounting the canopy on the end of a supporting pole.

The term "moulded canopy" used herein is intended to signify a canopy which is formed for example from metal using a die-casting process or which is moulded from plastics material, for example glass reinforced plastics (G.R.P).

Such a luminaire may be usedfora variety of purposes, such as the illumination of roads and yards.

Typically, the pole on which the luminaire isto be mounted is formed by the upper section of a lamp post and usually extends at an angle with respect to the remainderofthe lamp post,forexamplehori- zontal Iy. The pole may alternatively be mounted on a wall bracket ratherthan partofa lamp post.

Avariety of different types of mounting arrange menus for mounting luminaires on poles are known.

It is important particularly when the luminaire is used outdoors that the interiorofthe luminaire be made weatherproof. Water entering the interior of the luminaire where the control gear (ballast, ignitor, capacitor etc.) and light source are contained can ser iously damage these components, reduce efficiency, increase maintenance requirements and cause a safety hazard. For this reason, it has been common forthe mounting means to be arranged longitudinallyoffsetto one side of one end ofthe canopyand coveroftheluminaire,whichtogetherdefinethe control gear and light source containing enclosure, and attached thereto or formed in part integrallywith the canopy and extending therefrom.In such a construction the walls ofthe canopy and cover provide a physical barrier to the interior. In this way, adequate sealing ofthe light source containing enclosure can be ensured.

However,whilstthisarrangementenablesa range of mounting means to be employed readily, it has certain disadvantages. The provision ofthe mounting means separate from, and to one side of, the canopy and cover results in a complicated, and hence relatively expensive to produce, construction.

Moreover, because the mounting means are provided to one side of the canopy and cover, the overall length of the luminaire is increased and the centre of mass ofthe luminaire located at such a distance from the pole end thatsignificant bending moments are exerted on the pole, which, accordingly must be strong.

In order to overcome those disadvantages, a form of mounting means has been proposed which is situated overlying a part of the light-emitting portion of the luminaire ratherthan spaced longitudinally therefrom, thus reducing the overall length of the luminaire and forming a comparatively compact unit. This mounting means comprises a die-cast spigot either moulded as part of, or as an insert into, the canopy at its one end. In mounting the luminaire, the end ofthe pole is received in the spigotentryand one or more bolts are screwed through the wall of the spigot entryfrom the interiorofthe luminairefor ease of access which are tightened to push against the pole outer surface.Whilst this arrangement provides a comparatively compact luminaire, moving the centre of gravity of the luminaireclosertothe pole end, certain problems have been experienced.

Firstly, the moulded-in spigot entry is constructed for mounting on a particular size of pole end of a given diameter and cannot be converted for mounting on a pole end of different diameter. Secondly, as the bolts usedto clamp againstthe pole end passthrough threaded bores in a wall of the canopy from the in terior ofthe luminaire, the possibility exists that water can run along the surface ofthe pole and enter the interior ofthe luminaire through these threaded bores causing a safety hazard, reduced efficiency of the luminaire, etc.

It is an object ofthe present invention to provide a luminaire of the kind in which the mounting means is arranged overlying at least part ofthe light emitting portion ofthe luminaire having an improved form of mounting means and which is reliably sealed against the ingress of water, dust and the like and in which the aforementioned disadvantages are substantially avoided.

According to the present invention there is provided a luminaire comprising a moulded canopy and a l ig ht tra nsparent cover joined to the canopy which togetherdefinean enclosure in which a light source is accomodated, and means for mounting the canopy on the end of a supporting pole which means are arranged overlying at least part of the light emitting portion ofthe Iuminairewhich is characterised in that the mounting means comprises a U-shape clamping member whose legs pass through respective bores in a wall portion ofthecanopyintotheen- closure and whose base portion is to extend over the surface ofthe pole, securing means located within the enclosure and attached to the ends of the legsfor urging the base section towards the wall portion and thereby clamping the pole and a region ofthewall portion intermediate the borestogetherto mountthe canopy of the pole, and sealing means within each of the boresforsealing around a respective leg ofthe clamping member.

The use of a U-shape clamping member, for example, a U-bolt, in this manner provides a simple andconvenientformofmounting. By passing the legs ofthe clamping memberthroughthewall portion ofthe canopy into the enclosure a simplified form of construction is provided, as well as a comparatively compact luminaire. This arrangement has the further advantage that it is necessary onlyto openthecovertogainaccesstothesecuring means.

Moreover, even though the legs of the clamping member pass through the wall portion ofthe canopy into the enclosure for ease of access to the securng means, the provision of sealing means in each ofthe bores provides a simpleyetvery effective means of preventing water, dust and the like from passing through those bores into the enclosure.

Poles of different diameters may readily be accomodated by adopting an appropriately shaped and sized U-shape clamping member, although the spacing ofthe legs of the member is, of course, dictated by the spacing ofthe bores in the wall portion. In a preferred embodiment however, the base portion of the U-shape clamping member comprises two substantially straight sections inclined to one another each of which is arranged to engagetangentially a respective portion of the outer surface of the pole. The configuration enables a variety of different diameter poles to be accommodated by the same clamping memberwithinthe limits ofthe spacing of the member's legs.

The securing means may comprise a grab washer for each leg which is pushed over the leg from its free end, possibly whilst the leg is being pulled through theborewithasuitabletooltoclampthewall portion and poletogether,and againstthesurfaceofthewall portion adjacent the enclosure, the grab washer then biting into the leg to lockthe leg in position with re spectto the wall portion. Preferably though, to fac- ilitate dismantling, the securing means is disposed in the enclosure and attached to each leg by screwing onto a threaded end portion ofthe leg ofthe clamping member.

Each sealing means preferably comprises a deformable sealing element disposed in the respective bore and extending around the associated leg of the clamping member.

In a preferred embodimentthe sealing element is disposed adjacent a shoulder in the bore and is arranged to be compressed againstthe shoulder by a sleeve surrounding the leg which is urged inwardly ofthe bore by the securing means upon clamping of the luminaire on the pole so asto seal around the leg of the clamping member in fluid and dust-tight manner.

In another embodiment, the sealing element is cylindrical and is urged upon clamping of the luminaire on the pole inwardly ofthe bore by the securing means againsta shoulderinthe bore to deform radially and seal against the leg ofthe clamping member in fluid and dust-tight manner.

Both these arrangements have the advantage that until the U-shape clamping memberactuallyclamps the pole, the sealing elements are notcompressed against the peripheral surface of their associated leg, and hence the possibility of any damage occuring to the sealing element by movement of the leg within the bore priorto and during the clamping operation is avoided. Only upon clamping, is, the sealing element compressed to deform radially inwards ofthe boretosealaroundtheleg.

The securing means may includea metal plate having an aperture through which the leg extends, and which,when the canopy is clamped on the pole, bears against the surface ofthe wall portion facing the enclosure at least around the bore. Besides ser ving force the compressing sleeve orthecylindri- cal sealing element as the case may be into the bore during clamping to effectsealing by compressing the sealing element against the shoulder in the bore this plate also serves to provide additional strength andrigiditytoatleastareasofthewall portionsurrounding the bores.

Although a separate plate may be provided adjacent a respective leg of the clamping member, preferably a single metal plate is provided extending be tweenthetwoboresinthewall portion and having a respective aperture therein for each of the legs ofthe clamping memberforeven greaterstrength.

The mounting means may further include a metal sheet covering, and preferably also conforming to the surface profile of, the surface ofthe region ofthe wall portion remote from the enclosure which is clamped against the pole. In the case particularly where the canopy is moulded from plastics material, such as G.R.P., the metal sheet serves to distribute more evenly the forces acting on the wall portion upon clamping and to preventexcess local loading which might otherwise lead to damage being caused tothewall portion.

A luminaire in accordance with the present invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure lisa side elevation ofthe luminaire partly in cross-section, and Figure2 is an end view ofthe luminaire, again partly in cross-section, showing the mounting arran gementformountingthe luminaire on the end of a supporting pole.

Referring to the drawings, the luminaire shown (or lantern as itis sometimes called) is intendedfor street lighting purposes and comprises a generally elongate canopy 12 (otherwise known as a trough) of moulded G.R.P. material or high pressure die-cast aluminium to which a translucent diffusercover 14 (or bowl) of polycarbonate, acrylic or other suitable lighttransmitting material is attached around mating peripheral edges. A gasket 15 is disposed between the mating edges ofthe canopy 12 and cover i4com- pletelytherearound to seal the enclosure defined by those two parts in a fluid and dust-tight manner.The cover 14 issecured tothe canopy 12 by means of retaining clips 16 and 17 at opposite ends ofthe luminaire, the clips both being barbed at their one end and push-fitted at those ends in cooperating recesses in respective end walls of the cover to retain the clips on the cover. The opposite end of the retaining clip 16 is hook-shaped and passes through an apertured flange of the canopy and serves also as a hinge. The opposite end of retaining clip 17 on the otherhand is shaped to cooperatewith an end ledge ofthe canopy 12 in latching fashion so that the cover 14 can be swung open to provide access to the lum- inaire's interior.

A metal bracket 20 is attached to the canopy 12 within the enclosure by means of screws and supports a reflector 24 which extends along a substantial part of both the length and width of the enclosure defined by canopy 12 and cover 14and effectively partitions the enclosure into upper and lower parts 25 and 26 respectively. The reflector is supported at other points (not shown) on the canopy 12 by further fixing points. The upper part 25 ofthe enclosure containsthe luminaire's control gear (not shown) while the lower part 26 houses a low pressure sodium vapour discharge lamp 28 mounted in a lamp holder 29 carried by the bracket 20. The lamp 28 extends lengthwise ofthe luminaire. In operation, light produced by the lamp is emitted through the cover 14 over substantially its entire length.

The luminaire is adapted to be mounted on the end of a supporting pole, shown at 30 in the Figures, extending parallel to the longitudinal axis ofthe luminaire by means of a mounting arrangementtowards one end ofthe luminairewhich overlies an end section, generally indicated at31 in Figure 1, ofthe lightemitting portion of the luminaire determined bythe length and width ofthe diffuser cover 14. Inthisway, the overall length ofthe luminaire is kept to a minimum, being no longer than approximatelythe length ofthe light emitting portion ofthe luminaire.

Besides making the luminaire compact, the prov ision ofthe mounting arrangement overlying the light-emitting portion has the additional benefit that the centre of mass ofthe luminaire is located closer to the end ofthe supporting polethan would bethe case if, for example, the mounting arrangement were to be located offset longitudinally from the end of the cover 14 so that the bending moment applied to the polewhen the luminaire is mounted thereon is kept small.

The mounting arrangement, generally referenced 33 in Figure 2, is located in a region 34 bounded partly by a vertical end wall portion 35 and a generally horizontal wall portion 36 ofthe canopy 12, which constitute respectively parts ofthe boundary walls ofthe enclosure and hence separate in theregion from the enclosure. The region 34 is enclosed by a moulded cover 37 whose outer surface profile matchesthatofthecanopy 12. Referring to Figure 2, the cover37 is secured on the canopy 12 by a pair of integrally-formed webs 40 (only one of which isvis ible) extending inwardly which are push-fitted into barbed channels of z-shape clips 41 carried on a pair of upstanding webs formed integrally with the wall portion 36 of the canopy.

The end portion of the pole 30 is clamped against an area 44 ofthe outer surface ofthe wall portion 36 which is suitably shaped in theform ofatrough of V-shape section which extends axially of the lum inaire over a substantial part of the length ofthe region 34to receive and locate the outer peripheral surface ofthe pole end. Clamping is achieved by means of a U-bolt46. Thetrough-shape region 44 is covered by a conformingly-shaped metal sheet 48 with which the pole end contacts so that pressure exerted by the pole end is distributed over a greater area ofthewall portion 36 and localised stress is minimised. The base portion (bend) of the U-bolt46 comprises two mutuallyinclinedstraightsectionswhich engagethe pole 30tangentially on opposite sides of a central vertical plane through the pole.This configuration, togetherwiththev-shapetrough of the wall portion 36 enables differently diametered poles to be ac comodated readily.

The two legs 49 of the U-bolt 46 (only one of which is visible in Figure 2) pass through respective bores 50 extending through cylindrical bosses 51 formed integrally with the wall portion 36 on opposite sides ofthetrough-shaped region 44 (only one ofthe bosses and bores being visible in Figure 2) and pro ject into the enclosure defined by the canopy 12 and cover 14. The free ends of the legs 49,which are screw threaded, pass through respective apertures in a metal plate 53 extending across the underside of the wail portion 36 between the two bores 50 and are each fitted with a washer 55 and nut 56.

The bores 50,which maybeformed during moulding or by drilling, each have an increased diameter portion which terminates at a sloping shoulder part way along the bore against which an annular sealing element 57, for example, a rubber or similar material O-ring, is seated. Within the increased diameter portion ofthe bores 50 there is arranged a cylindrical pressure sleeve 58, of plastics or metal which sur rounds the associated leg 49 of the U-bolt 46.

In the unclamped state of the mounting arrangement, the pressure sleeve 58 projects slightly beyond the level ofthe lower entrance to the bore 50.

When clamping ofthe pole 30 is required, the nut 56 on each leg is tightened forcing, via washer 55, the plate 53 upwardly toward the lower surface ofthe bosses 51 which in turn pushes the pressure sleeve 58 inwardly ofthe bore 50 to compress the annular sealing element57againsttheshoulderinthebore causingtheelementtodeform radially inwards of the bore and seal in fluid-tight manner around the leg 49 ofthe U-bolt. Tightening ofthe nuts 56 in this manner also serves to clamp the plate 53 against the wall portion 36 and pull the legs 49 downwardly so astoclampthetrough-shaped region44ofthewall portion 36 firmly againstthe pole thereby mounting the luminaire on the pole end.

Ratherthan using a separate annular sealing element 57 and pressure sleeve 58 in each bore, a single cylindrical sleeve-like sealing member of a material capable of deformation, at least at its inner end under pressure from the plate 53, to seal around the leg 49 may be used instead. In this case, the sealing member engages directly with the plate 53. Also, two metal washers may be used instead ofthe single plate 53 shared by both legs 49, each ofthese washers extending around a respective leg 49 and overlying the entrance to the bore 50. However, it is preferred to use a single plate 53 as described above since this plate affords increased rigidity and strength to the wall portion 36 enabling it to withstand easily the clamping forces involved.

Cables from the pole 30 pass through a fluid and dust-tight gland 59 mounted in an aperture in the wall 35 and are connected to terminals of the control gear.

It will be seen therefore that any water entering the region34eitheraroundtheedgesofthecover37or along the surface of the pole 30 is prevented from reaching the luminaire enclosure, thus avoiding the possibility of damage occurring to the lamp orthe control gear contained therein. Any water which finds its way into the region 34 is directed bythe surface shape ofthe wall portion 36 into a centrallyarranged drainage channel 60 which opens to the outside ofthe luminaire through the cover 37.

Claims (11)

1. A luminaire comprising a moulded canopy and a light transparent coverjoined to the canopy which together define an enclosure in which a light source is accommodated, and means for mounting the canopy on the end of a supporting pole, which means are arranged overlying at least part of the lightemitting portionoftheluminaire,characterised in that the mounting means comprises a U-shape clamping member whose legs pass through respective bores in a wall portion ofthe canopy into the enclosure and whose base portion is to extend over the surface ofthe pole, securing means located within the enclosure and attached to the ends of each ofthe legs for urging the base section towards the wall por tion and thereby clamping the pole and a region of the wall portion intermediate the bores together to mountthecanopyon the pole, and sealing means within each of the bores for sealing around a respective leg ofthe clamping member.

2. Aluminaire accordingto Claim 1,characterised in that each sealing means comprises a deformable sealing element disposed in the respective bore and extending around the associated leg ofthe clamping member.

3. A luminaire according to Claim 2, characterised in thatthe sealing element is disposed adjacent a shoulder in the bore and is arranged to be compressed againstthe shoulder by a sleeve surrounding the leg of the clamping member which is urged inwardly ofthe bore by the securing means upon clamping ofthe canopy on the pole so asto seal aroundtheleg.

4. A luminaire according to Claim 2, characterised in that the sealing element is cylindrical and engages with the securing means, the sealing element being urged upon clamping ofthe luminaire on the pole inwardly ofthe bore by the securing means against a shoulder in the bore to deform rad ially and seal against the leg ofthe clamping member.

5. A luminaire according to any one ofthe preceding claims, characterised in that the securing means for each leg of the clamping member is attached to the leg by screwing onto threaded end portion ofthe leg.

6. A luminaire according to Claims, characterised in that the securing means for each leg of the clamping member includes a metal plate having an aperture through which the leg extends, and which, when the canopy is clamped on the pole, bearsagainstthesurfaceofthewall portionfacing the enclosure at least around the bore.

7. A luminaire according to Claim 6, characterised inthatthe metal plate for each leg comprises a single metal plate extending between the two bores in the wall portion and having a respective aperture therein for each of the legs of the clamping member.

8. A luminaire according to any one ofthe preceding claims, characterised in that the mounting means further includes a metal sheet covering the surface ofthe region ofthewall portion remote from the enclosure which is clamped againstthe pole.

9. A luminaire according to Claim 8, characterised in thatthe metal sheet conforms to the surface profile ofthe region ofthewall portion.

10. A luminaire according to any one ofthe preceding claims, wherein the base portion of the Ushape clamping member comprises two substantially straight and mutually inclined sections each of which is arranged to engage tangentially a respective portion ofthe outer surface ofthe pole.

11. A luminaire substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.