GB2174181A

GB2174181A - Light fitting

Info

Publication number: GB2174181A
Application number: GB08508939A
Authority: GB
Inventors: Stephen Mark Hall
Original assignee: Quantum Lighting Ltd
Current assignee: Quantum Lighting Ltd
Priority date: 1985-04-04
Filing date: 1985-04-04
Publication date: 1986-10-29
Also published as: GB8508939D0

Abstract

The lamp holder 12, 14 of an adjustable light fitting is carried on pivot studs 11 which in turn are carried in a conical shield 4 which can rotate about its axis. The lamp holder includes a bracket 12 and a cylindrical cowl 15 for the lamp 1 has integral, snap projections 17 which engage over the rear end of the bracket 12, enabling the cowl 15 to be slipped on and off without difficulty. The axis of the pivot studs 11 is in the plane of the extreme ends of an opening in the shield 4 through which the cowl 15 passes; in this way, the gaps around the cowl 15 appear to be of minimum size. To restrain the bracket 12 against free pivoting movement, there is a sprung hoop 21 which engages the rear end of the bracket 12 and is slightly smaller radius than that required so that it is distorted outwards, thereby applying a frictional restraint to the bracket 12 in a very simple manner. <IMAGE>

Description

SPECIFICATION Light fitting The Invention According to a first aspect of the invention, there is provided a light fitting as set forth in Claims 1 or 8. As it is very difficult to provide sufficient air circulation around the lamp (for cooling) without stray light illuminating the rear part of the fitting, it is desirable to provide some arrangement for preventing the stray light being visible from in front as it detracts from the appearance of the lamp and fitting.

By having the pivot axis of the lamp holder generally in the plane of the opening, and by suitable shaping of the opening, the stray light in practice is not at all apparent. Although, at least in the central position of the lamp holder, there will be gaps at each end of the opening, these gaps are most apparent when looking straight at the lamp along its axis-- normally one does not do this due to the intensity of light.

According to a second apsect of this invention, there is provided a light fitting as set forth in Claims 9 or 14. The hoop provides a very simple way of securing the lamp holder against accidental pivotal motion, whilst readily permitting adjustability.

According to a third aspect of the invention, there is provided a light fitting as set forth in Claims 15 or 19. Normally, changing the lamp presents a problem when there is a cylindrical lamp cowl, because there is insufficient of the lamp protruding to grasp it, or because the cowl extends beyond the end of the lamp.

The cowl should be easily removable so that the lamp can be changed quickly, particularly by someone reaching upwards where the light fitting is in the ceiling. A combination of the special bracket and the special cowl enables the cowl to be withdrawn without difficulty.

The various aspects of the invention can be combined. The Claims not recited above claim optional features of the invention.

Preferred Embodiment The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front view of a light fitting in accordance with the invention; Figure 2 is a rear view of the light fitting; Figure 3 is a half section along the line Ill-Ill in Figure 1; and Figure 4 is a section along the line IV-IV in Figure 1.

The light fitting is for receiving a 12 volt lamp 1 with a built-in reflector-the lamp 1 shown is a special display lighting spot lamp, but the fitting can be alternately for an accent light. The fitting is arranged for mounting in a structure such as a ceiling or false ceiling, or a wall or partition.

The fitting has a mounting member in the form of a housing 2 which has suitable screw or bolt holes etc for mounting in position and is generally in the form of a square crosssection sleeve. The housing 2 has an internally-projecting flange 3 which defines a circular opening; in it is received a shield 4 which also acts as a chassis. As can be seen in Figure 4, the shield 4 bears against the front of the flange 3 and is secured in position by an annular member or retaining ring 5 which bears against the rear of the flange 3. The retaining ring 5 is fixed to the shield 4 by means of pins 6 (which are for instance moulded into the shield 4) and star-lock washers or Circlip retainers 7.The mounting of the shield 4 enables it to be rotated through 360" about the axis of the housing 2, the flange 3 and the surfaces which it engages providing frictional resistance-this enables the light fitting to be adjustable in one sense.

The shield 4 is of concave and specifically conical shape, having small steps to reduce reflection in a conventional manner. The shield 4 has an elongate opening 8, which is further described below.

The shield 4 has diametrically-opposed bosses 9 which provide recesses 10. These recesses 10 receive lateral projections in the form of trunnions or studs 11 which are secured to and form a pivot mounting for a bracket 12. As shown in Figure 3, the pins 11 are retained in position by the retaining ring 5. The bracket 12 is of generally pi (H)- shape, having parallel limbs which extend down either side of the lamp 1, joined by a rear end piece which is to the rear of the lamp 1 (see Figure 3); the pins 11 are secured to the open ends of the limbs. As shown in Figure 2, the rear end piece has two notches 13 adjacent one side, whose purpose is described below. The bracket 12 carries a conventional lamp holder fitting 14 which in turn carries the lamp 1. The bracket 12 and lamp holder fitting 14 in effect form a lamp holder.

The arrangement is such that the lamp 1 can be pivoted about an axis generally at right angles to the axis of the shield 4.

Surrounding the lamp 1, there is a cylindrical cover or cowl 15. The cowl 15 is inserted or slipped on over the lamp 1 and bracket 12 from the front, and has respective longitudinal slots 16 to allow it to pass over the studs 11, the slots 16 terminating at the studs 11, as can be seen in Figure 3. The cowl 15 has integral snap projections 1 7 at its rear end, the projections 1 7 being on short legs and sprung by the inherent resilience of the material. There are four snap projections 17, two immediately on either side of each slot 16.As can be seen in Figure 4, the snap projections 17 have opposed inclined surfaces. and the dimensioning is such that when the cowl 15 is pushed over the bracket 12, the snap projections 17 are cammed radially outwards by the rear end piece of the bracket 12 and then engage over the rear end piece to lock the cowl 15 in position; when the cowl 15 is pulled off, the snap projections 17 are again cammed radially outwards to permit removal.

The cowl 15 has internal lugs 18 which carry a disc 19 of protective glass, primarily to give protection should the lamp 1 explode.

The disc 19 is held in position by a Circlip 20.

The cowl 15 projects through the elongate opening 8. As can be seen in Figure 1, the long sides of the opening 8 pass close to the cowl 15 and the ends of the opening 8 lie close to the cowl 15 when the cowl 15 is pivoted into its respective extreme positions.

The opening 8 is concave as seen looking along the axis of the studs 11 (see Figure 4).

The axis of the studs 11 is in the diametrical plane which lies half way between the end of the opening 8 in the front face of the shield 4 and the end of the opening 8 in the rear face of the shield 4, as indicated by the dot-dash line in Figure 4.

The cowl 15 encloses the lamp 1 and shields stray light, though some light will inevitably pass out through the openings around the lamp holder fitting 14. By having the axis of the pivot studs 11 in the plane of the extreme ends of the opening 8, the opening 8 is of minimum size, and the conical shape of the shield 4 assists in reducing the effective visibility of the gaps between the cowl 15 and the edges of the opening 8. When the cowl 15 is pivoted to one side, the part of the cowl 15 which cooperates with the respective extreme end of the opening 8 is behind the diametrical plane of the cowl 15 in which the pivot axis lies. In the arrangement shown, the lamp holder and cowl 15 can tilt 45" on either side of the axis of the housing 2.

In order to provide restraint to secure the lamp holder fitting 14 and cowl 15 in position whilst permitting their adjustability, there is a spring wire hoop 21 whose ends pass through holes in the shield 4 and are bent over, to secure the hoop 21 in position. The hoop passes from one side of the lamp holder fitting 14 to the other and is sprung against the rear of the bracket 12, engaging in the notches 13. In order to do this, the hoop 21 is slightly too short to assume a circular shape (i.e. of slightly smaller radius than that required) and is distorted outwards by the bracket 12. In this way, the hoop 21 applies frictional resistance to the pivoting motion of the bracket 12. As can be seen in Figure 2, the hoop 21 is adjacent one side of the bracket 12, and thus does not interfere with any leads etc of the lamp holder fitting 14.

The housing 2, shield 4 and retaining ring 5 can be injection moulded in a black resin such as "Noryl 150", a polyphenoleneoxide, and the cowl 15 can be injection moulded in a black resin such as "Ultem", a polyetherimide; both these resins are heat resistant and flame retardant. The bracket 12 can be formed in mild steel.

Claims

1. An adjustable light fitting for mounting in a structure such as a ceiling, wall or partition, comprising: a mounting member; a lamp holder; means mounting the lamp holder on the mounting member for pivoting movement about an axis generally at right angles to the axis of the lamp holder and for securing the lamp holder in relation to the mounting member; a generally cylindrical cowl, secured with respect to the lamp holder, for surrounding the lamp; and a concave shield secured to the mounting member and having therein an elongate opening through which the cowl projects, the pivot axis of the lamp holder being generally in the plane of the opening, the longitudinal sides of the opening passing close to the cowl, and the extreme ends of the opening lying close to the cowl when the lamp holder is pivoted into its respective extreme positions.

2. The light fitting of Claim 1, wherein said axis is substantially in the plane of the extreme ends of the opening.

3. The light fitting of Claim 1 or 2, wherein the shield is generally conical.

4. The light fitting of any of the preceding Claims, wherein the shield carries pivot bearings mounting the lamp holder.

5. The light fitting of Claim 4, wherein the shield is rotatable with respect to the mounting member substantially about the axis of the shield.

6. The light fitting of Claim 4 or 5, wherein the mounting member has an internally-projecting flange defining an opening in which the shield is received, the shield bearing against the front of the flange and being secured in position by an annular member fixed to the shield and bearing against the rear of the flange.

7. The light fitting of Claim 6, wherein the lamp holder has transversely-projecting studs which are received in diametrically-opposed recesses in the shield, to form said pivot bearings.

8. An adjustable light fitting, having the cowl and shield arrangement substantially as herein described with reference to, and as shown in, the accompanying drawings.

9. An adjustable light fitting for mounting in a structure such as a ceiling, wall or partition, comprising: a mounting member; a lamp holder; means mounting the lamp holder on the mounting member for pivoting movement about an axis generally at right angles to the axis of the lamp holder; a hoop secured with respect to the mounting member and extending around the back of the lamp holder and from one side of the lamp holder to the other, the hoop being sprung against the rear of the lamp holder so as to engage the lamp holder and resist pivoting motion of the lamp holder about said axis, thereby permitting adjustability of the lamp holder but securing the lamp holder in position.

10. The light fitting of Claim 9, wherein the hoop is made of spring material and is distorted from its natural position by the lamp holder.

11. The light fitting of Claim 9 or 10, wherein the lamp holder comprises a bracket of generally n-shape, having parallel limbs which will extend down either side of the lamp, joined by a rear end piece which will be to the rear of the lamp, the rear end piece having at least one notch in which is engaged the hoop.

12. The light fitting of any of Claims 9 to 11, wherein the hoop is to one side of the axis of the lamp holder.

13. The light fitting of any of Claims 9 to 12, wherein there is a shield secured to the mounting member with an opening in which the lamp will be received, the ends of the hoop being secured to the shield.

14. An adjustable light fitting, having the lamp holder and hoop substantially as herein described with reference to, and as shown in, the accompanying drawings.

15. A light fitting comprising: a mounting member; a lamp holder comprising a bracket which is of generally shape, having parallel limbs which will extend down either side of the lamp, joined by a rear end piece which will be to the rear of the lamp, the bracket being mounted on the mounting member by means of lateral projections at the ends of the limbs remote from the rear end piece; and a generally cylindrical cowl, for surrounding the lamp, the cowl having been inserted over the bracket from the front of the lamp and having respective longitudinal slots to allow it to pass over said lateral projections and having integral sprung projections at its rear end, which sprung projections are cammed radially outwards by the rear end piece of the bracket when the cowl is pushed over the bracket and then engage over the rear end piece, and are also cammed radially outwards when the cowl is pulled off, to allow removal of the cowl.

16. The light fitting of Claim 15, wherein the cowl and the sprung projections are formed by an integral plastics moulding.

17. The light fitting of Claim 15 or 16, wherein the transverse projections form a pivot mounting in the mounting member, for pivoting movement of the lamp holder about an axis generally at right angles to the axis of the lamp holder.

18. The light fitting of any of Claims 15 to 17, wherein there are four sprung projections, two immediately on either side of each said slot, there being two said transverse projections and two said slots.

19. A light fitting, having the generally cylin drical, removable cowl for surrounding the lamp and the snap fitting substantially as herein described with reference to, and as shown in, the accompanying drawings.

20. A light fitting as defined in all of or any two of a) Claims 1 to 8, b) Claims 9 to 14, and c) Claims 15 to 19.