GB2059566A

GB2059566A - A plastics reflector for a headlamp

Info

Publication number: GB2059566A
Application number: GB8031918A
Authority: GB
Original assignee: Westfaelische Metall Industrie KG Hueck and Co
Current assignee: Westfaelische Metall Industrie KG Hueck and Co
Priority date: 1979-10-04
Filing date: 1980-10-03
Publication date: 1981-04-23
Also published as: GB2059566B; IT8068306A0; BR8006268A; FR2466705B1; ES253318U; AU6180980A; DE2940249A1; AU533996B2; IT1128978B; FR2466705A1; ES253318Y; DE2940249C2

Abstract

A plastics headlamp reflector is moulded or cast with a neck (2) forming a rear opening in which a metal bulb holder (1) is inserted. Integrally moulded arms (12) on the neck have forwardly extending free ends which bear inwardly projecting lugs (13) that engage in openings in the bulb holder to retain it in place. The front faces of the lugs provide locations for the bulb holder so that the same reflector mould part that forms the reflecting surface also forms these locating faces. Resilient bridge portions (16) of a front rim (15) on the neck (2) urge the bulb holder into engagement with said lug front faces. At its rear the bulb holder has a flange (6) closing an annular recess surrounding the neck of the reflector to form a ventilation channel connecting the headlamp interior to the exterior through peripherally spaced openings (9, 10). <IMAGE>

Description

SPECIFICATION A plastics reflector for a headlamp The invention relates to a plastics reflector for a headlamp, in particular for a motor vehicle headlamp, which is produced by die casting or injection moulding methods, and is provided with a bulb holder which is inserted from the rear into a rear opening of the reflector for accommodating a lamp bulb having a bearing flange.

With plastic reflectors of this type, the rear opening of the reflector may be socket shaped, comprising a forwardly projecting neck in which the lamp holder is located, the holder lying on a rear face of the relfector. In the casting or moulding operation, this face will be formed by the rear one of the two mould parts which, when the mould is closed, does not necessarily always reach the same end position relative to the mould half forming the reflective face of the reflector.

Large dimensional deviations can therefore occur from the bearing face of the bulb holder to the reflective face of the reflector and relatively accurate positioning of the bulb relative to the reflective face of the reflector is only possible if, for example, the bearing face of the bulb holder is corrected by expensive finish machining.

Machine finishina could be avoided if the bulb holder can be inserted into the reflector from the front to rest on a face which is formed by the tool half that forms the reflective face of the reflector, but the disadvantage of this arrangement is that the head-lamp can only be assembled (assembly from only one side) using complicated devices, i.e.

the headlamp is not appropriately formed to be assembled so that the parts of the reflector to be assembled as a basic unit can be mounted from one side. As the reflector has to be twisted from the front during insertion of the lamp holder and then has to be twisted from the rear in order to fix it, it is impossible to avoid damaging the sensitive reflective face of many reflectors. This additional handling makes it difficult to train the work force and demands expensive assembly work.

An object of the invention is to provide an arrangement in which the bulb holder can be inserted easily and simply into the reflector from the rear and in which the bulb holder can be inserted easily and simply into the reflector from the rear and in which the bulb inserted into the bulb holder can assume and maintain its established theoretical position relative to the focus of the reflector.

According to the invention there is provided, a plastics reflector for a headlamp provided with an annular bulb holder inserted from the rear into a rear opening of the reflector for accommodating a lamp bulb having a bearing flange, the reflector opening having inwardly projecting elements, arranged to have the bulb holder resting on transversely directed front faces of said elements, i.e. faces that are oriented towards the direction of light emission from the headlamp.

Advantageously, said projecting elements are designed so as to be resiliently flexible in the radial direction and engage in the bulb holder. A separate retaining means for the bulb holder is not therefore needed.

This arrangement may have the elements formed as resilient arms that project into a neck of the reflector that forms said rear opening from its outer edge, with free ends of the arms extending in the direction of light emission and each having a lug which projects radially towards the reflector axis for engaging in a respective opening in the bulb holder, and at least one lug corresponds in width to the width of its engagement opening in the bulb holder. In this way, the bulb holder can be not only fixed in the axial direction but also secured against twisting.

It is also advantageous if the neck of the reflector at its end projecting in the direction of light emission has an end wall which is formed only as an outer rim and is apertured in the regions of the resilient arms, and where weakened in cross-section by the apertures is formed as a corrugated bridge. The apertures in the end wall permit simple assembly of the injection moulding tool for the reflector, whereas the corrugated bridges form springs which urge the bulb holder against the front faces of the resilient arms. The bulb holder can be simply and easily assembled as it can be inserted into the neck of the reflector where it will automatically engage by pressure and be held against the faces of the inwardly projecting elements without an additional operation or an additional fixing member.The bulb holder is also secured against twisting relative to the reflector.

Another advantage lies in the fact that the bulb holder may be formed from metal. This permits dissipation of heat outwards to give a reduction in the temperature of the bulb which heats up markedly. Moreover, deformation of the bearing face of the bulb, which is possible with a bulb holder produced from plastics, does not occur.

Preferably, the bulb holder is dished or potshaped in form, with a rear or upper edge having an external flange and forming a cover for an annular groove surrounding the reflector neck, said flange thereby complementing the annular groove to form a tubular ventilation duct. Such a tubular channel can have the function of allowing inward and outward ventilation of the enclosed cavity formed by the reflector and diffusing disc. In order to seal the channel, it is desirable if the bulb holder is adhered firmly to the reflector in the region of the external flange. This adhesion therefore assists and relieves the fixing of the bulb holder by means of the engaging lugs.

Furthermore, this metallic bulb holder dissipates the heat produced on the bulb arrangement outwards.

An embodiment of the invention is shown by way of example in the accompanying drawings, in which: Fig. 1 shows a central longitudinal slot through the neck of a reflector according to the invention, Fig. 2 shows the plan view of the neck of the reflector of Fig. 1 from the rear, Fig. 3 shows the same direction plan view of the neck of the reflector but without the bulb holder, and Fig. 4 is a detail sectional view along line A-A in Fig. 1.

The drawings show a bulb holder 1 produced from sheet steel inserted into neck 2 forming the rear opening of a cast or moulded plastics reflector 3. The bulb holder 1 accommodates a bulb 4 and is dished or pot-shaped in shape, the bulb 4 resting on an end wall 5 which extends as a rim only over the outer edge region. The bulb holder 1 is flanged in its rear region and forms a cover 6 for an annular recess 8 in the reflector surrounding the neck 2 and formed by the neck and an integral collar 7 running round the neck. The resultant tubular annular channel 6, 8 is connected to the cavity formed between the reflector 3 and the front glass or diffusing lens (not shown) by an opening 9 and, on the other side of the annular channel 6, 8 it is connected to the exterior by an opening 10, thereby providing a ventilation passage for the headlamp interior.

The reflector neck 2 has three internal bulges 11 spaced uniformly round its periphery, at which there are inwardly extending resilient arms 12 also moulded on the reflector neck. The free ends of the resilient arms 12 point forwards, in the direction of light emission, and each bears a lug 13 projecting radially inwards towards the reflector axis. The lugs 13 engage in rectangular openings 14 punched in the metal bulb holder 1, the width of at least one lug 13 corresponding to the width of the openings 14 in the bulb holder 1.

The reflector neck 2 projects into the interior of the reflector 3 and has at its forward end facing the direction of light emission an end wall 1 5 which is formed only as an inner peripheral rim. In the region of each resilient arm 12 the wall 1 5 is apertured and is there formed as a corrugated bridge. The bridges 16 bear under initial stress on the bottom 5 of the bulb holder 1 and press it against the frcnt faces 1 7 of the lugs 1 3 projecting into the interior of the reflector. These faces are oriented towards the direction of light emission from the headlamp, although they are not necessarily perpendicular to the reflector axis, and in the injection moulding or die casting of the reflector they can be formed by the same moulded part as the reflective surface, so that their axial spacing from that surface is precisely determined.

This in turn allows the lamp bulb to be accurately positioned relative to the focus of the reflective surface.

Before insertion of the bulb holder 1, some adhesive 1 8 should be applied to its flanged edge acting as the cover 6 to adhere it to the adjoining surfaces of the reflector moulding.

Claims

1. A plastics reflector for a headlamp provided with an annular bulb holder inserted from the rear into a rear opening of the reflector for accommodating a lamp bulb having a bearing flange, the reflector opening having inwardly projecting elements, arranged to have the bulb holder resting on transversely directed front faces of said elements.

2. A plastics reflector according to claim 1, wherein said elements are resiliently flexible in the radial direction and engage in the bulb holder.

3. A plastics reflector according to claim 2, wherein the engaging elements comprise resilient arms projecting inwardly of the reflector rear opening, said arms having free ends extending in the direction of light emission and each carrying a lug extending radially towards the reflector axis and capable of engaging in a respective opening in the bulb holder.

4. A plastics reflector according to claim 3, wherein at least one lug of the arms corresponds in width to the width of its engagement opening in the bulb holder.

5. A plastics reflector according to any one of the preceding claims, wherein said rear opening is formed by a neck portion of the reflector extending forwardly in the direction of light emission and said neck portion has at its forward end a rim-like end wall that is apertured in the region of said inwardly projecting elements.

6. A plastics reflector according to claim 5, wherein the end wall is corrugated in the region of said apertures.

7. A plastics reflector according to any one of the preceding claims, wherein the lamp holder is produced from metal.

8. A plastics reflector according to any one of the preceding claims, wherein the lamp holder is dished or pot-shaped in form, and with a rear edge having an external flange forming a cover for an annular recess in the reflector surrounding the rear opening and forming therewith a tubular ventilation duct for the reflector interior.

9. A plastics reflector according to any one of the preceding claims, wherein the bulb holder-is adhesively connected to the reflector.

10. A plastics reflector constructed and arranged for use substantially as described herein with reference to the accompanying drawings.