GB2148479A

GB2148479A - Ventilated headlamp for vehicles

Info

Publication number: GB2148479A
Application number: GB08425510A
Authority: GB
Inventors: Alfred Ewert
Original assignee: Westfaelische Metall Industrie KG Hueck and Co
Current assignee: Westfaelische Metall Industrie KG Hueck and Co
Priority date: 1983-10-19
Filing date: 1984-10-09
Publication date: 1985-05-30
Also published as: ES281766Y; FR2553866A1; IT8467979A0; GB8425510D0; DE3337896C1; ES281766U; GB2148479B; IT1179137B; FR2553866B1

Abstract

A ventilated headlamp for vehicles has a reflector (2) produced by an injection-moulding or die- casting process. The interior (1) is sealed off from dirt and water spray and for its ventilation a groove (16), which is open towards the rear, is provided in a ring (11, 12) which surrounds a reflector opening (7) for receiving the bulb and which is made integral with the bulb socket or holder (9) secured to the reflector. The groove is covered by a sealing cover (13, 14). The reflector has a stepped back as a result of sections (3, 4, 5, 6) with different parabloids. The ring rests on a surface (10) formed from an extension of the reflector to locate the bulb socket in the direction of the optical axis. <IMAGE>

Description

SPECIFICATION Ventilated headlamp for a vehicle The invention relates to ventilated vehicle headlamps.

A vehicle headlamp is known from DE-PS 25 24 1 62 having a reflector produced by a moulding or casting process and in which the interior bounded by the reflector is sealed off from the environment, at least with respect to dirt and water spray, and a groove having a trough-shaped cross-section and open towards the rear is set in a ring surrounding the reflector opening that receives the bulb, in order to ventilate the interior, and is covered by a sealing cover. In this example, the groove, which is open towards the exterior of the reflector, is formed on the reflector which completes a covering cap to form a tubular passage.Such headlamps have the advantage that the reflection surface of the reflector is sealed off from dirt and water spray and no water collecting at accidental leakage points is sucked into the interior of the reflector-diffusing-lens unit. Furthermore, it is an advantage that the moisture content of the air present in the reflector-diffusing-lens unit is adapted to the moisture content of the air surrounding the headlamp in a sufficiently short time.

Vehicle headlamps are also known wherein the reflector is divided into a plurality of sections of different parabloid areas. As a result, an optimum light yield and light distribution can be achieved, particularly in headlamps with dipped and main beams.

Furthermore, head lamps are known, the reflectors of which are produced from plastics material by an injection-moulding or pressing process. The plastics material should have a high dimensional stability under heat, and sufficient rigidity and freedom from distortion.

Plastics materials are already known which have such advantageous properties to an adequate extent and in addition are inexpensive.

The best known representatives of these plastics materials are the low-profile polyester resins which, when processed, result in mouldings with greatly reduced shrinkage, to some extent even zero shrinkage. Reflectors produced from such plastics material have to be varnished before the vapour deposition of the reflecting layer because the reflecting layer cannot be vapour-deposited directly as in the case of the very expensive thermoplastics which have comparably satisfactory properties.

In the case of a vehicle headlamp the reflector of which is divided into a plurality of sections with different parabloid areas, the reflector cannot be varnished by the rotary method as described in the DE-OS 1 7 72 1 20. Such reflectors have to be varnished by dipping in order to obtain a smooth surface for the reflecting layer to be vapour deposited.

In this case, the reflector must be immersed in the bath with the light exit opening first. If the reflector were immersed with its back first, varnish would accumulate in depressions which result through the sections not lying on the same parabloid plane and furthermore, the varnish surface would be contaminated in the phase of draining off the varnish and of stoving the varnish. Rotary varnishing, as in the case of reflectors with a uniform parabloid surface, is not possible because reflector sections with different focal lengths require a different speed of rotation and projecting corners and edges result through the reflector sections, as a result of which varnish runs occur on the component parabloid surfaces or an uneven surface structure results.If such a reflector is to comprise a ventilating system as described above, then an automatic varnishing of the reflector by dipping is not possible or is very complicated. During the immersion of the reflector with its light exit opening first, the varnish would accumulate in the groove open towards the back of the reflector.

A vehicle headlamp is known from DE-OS 22 34 123, the reflector opening of which is surrounded by a ring to receive the bulb. The ring has a trough-shaped groove which is open towards the rear and is stuck to the back of the reflector. A ring of this type cannot be used for a reflector the back of which is stepped in construction as a result of a plurality of sections with different parabloids. In addition, in such a vehicle headlamp with a reflector made of plastics material, it is a disadvantage that the heated lamp plate of the bulb rests directly on the reflector.

The invention is based on the object of drawing from the vehicle head lamps described above in such a manner that their advantages come into full play while their disadvantages are eliminated. In this case, the reflector is to be varnished by dipping in order to obtain as smooth a surface as possible for the reflecting layer to be vapour-deposited and in addition varnish should not be able to accumulate in any depression during the varnishing by dipping.In a headlamp according to the invention in which the reflector has a stepped rear face as a result of sections with different parabloids, a ring surrounds the reflector opening at the apex of the reflector and is made integral with a holder or socket for the headlamp bulb, said ring lying on a surface formed by an extension of the reflector, and the bulb socket comprises an internal flange at one end to support the lamp plate of the bulb and an external flange at its other end, which forms a rearwardly open groove which is U-shaped in cross-section.

The bulb socket can advantageously be made from die-cast zinc because it is possible to use a tool that is simple in construction and to ensure that the bulb socket is easy to remove from the mould. In addition, the bulb socket is located in the optimum manner in the direction of the optical axis of the reflector by a contact surface extending round the opening to receive the bulb and moreover no accumulations of varnish form on the contact surface during the varnishing bv dipping such as might form, for example, with extensions projecting radially in the neck of the reflector.

Such accumulations of varnish would have to be removed by time-consuming finishing. As a result of forming the groove from an external flange of the bulb socket, the bulb socket can be very large in area, as a result of which the heat of the bulb is satisfactorily drawn off to the outside.

Furthermore, it is an advantage if the sealing cover closing the trough-shaped groove is formed from a seal pressed into the groove with a press fit. Such an arrangement can be produced very inexpensively because as a result of the covering cap placed on the bulb socket, the tubular passage can only be sealed towards the interior and exterior of the refiec- tor if the covering cap is made very exact in size and in addition such a covering cap is very difficult to mount. In utilising this preferred feature of the invention, a seal of cord can be used for the seal inserted in the groove.

The bulb socket can be firmly and tightly connected to the reflector in a simple manner if the socket is stuck to the reflector in a sealed manner at the encircling marginal region of the opening that receives the bulb.

It is a further advantage if the covering screen of the bulb is secured directly to the bulb socket. As a result, the heat of the heated screen can be drawn off directly to the outside via the bulb socket of large area.

An embodiment of the invention is illustrated in the accompanying drawings by way of example. In the drawings; Figure 1 shows a longitudinal section through a ventilated headlamp for a vehicle, the reflector of which comprises a plurality of sections which do not lie on the same parabloid plane, and Figure 2 shows a view in the direction X into the interior of the reflector.

The reflector 2, which is connected to diffusing lens 1 in a sealed manner, is produced from low-profile resin. The light exit opening of the reflector 2 is rectangular. The inner reflecting surface contains a pair of first reflecting sections 3 and 4 and a pair of second reflecting sections 5 and 6. These first and second reflecting sections extend over the reflector at opposite sides of the rear opening 7 of the reflector and extend to the light exit opening at the front of the reflector. The first reflecting sections 3 and 4 are parabloid in shape and lie on the same parabloid plane, while the second reflecting sections 5 and 6 are parabloid in shape but do not have a common focal point. The reflecting sections 3, 4 and 5 are designed in the optimum manner for a dipped beam and the reflecting section 6 is designed in the optimum manner for main beam.

The opening 7 receiving the bulb 8 is disposed at the apex of the reflector 2. Inserted in the opening 7 from the back of the reflector is the bulb socket 9 to which a lamp screen or cover 1 8 following the bulb 8 is secured directly. The surface 10 which is formed by the marginal region surrounding the opening 7 to receive the bulb 8, serves to locate the bulb holder or socket 9 in the direction of the optical axis of the reflector. In this region, the bulb socket 9 is stuck to the reflector 2 in a sealed manner. The external flange 1 9 of the bulb socket, which projects out of the opening 7 of the reflector 2, forms a double-walled collar 1 1 and 1 2 which extends coaxially to the optical axis of the reflector.The two arms of the double-walled collar 1 1 and 1 2 form a trough-shaped groove in cross-section, which surrounds the opening 7 as an annular groove. This annular groove is open towards the rear and is completed by a cord seal 1 3 pressed into the annular groove to form a tubular passage 1 6.

The opening 7 of the reflector 2 is covered by a covering cap 14. The lamp plate 21 of the bulb 8 rests on internal flange 20 of the bulb socket 9.

An opening is provided both in the inner wall portion 11 and in the outer wall portion 1 2 of the double-walled collar. The opening 1 5 in the outer wall portion establishes the communication from the outside air to the tubular passage 16, and the opening 1 7 in the inner wall portion 11 establishes the communication from the tubular passage 1 6 to the interior of the headlamp. The opening 1 5 is situated at the lowest point of the collar 1 2 so that condensate emerging from the passage, which acts as a condenser at the same time, can flow out of the passage. The opening 1 7 establishing the communication between the passage 1 6 and the interior of the headlamp is disposed in the highest point of the inner wall 11 of the collar in order to obtain an adequate length for the passage.

In the case of such a vehicle headlamp, the reflector 2 can be immersed in the bath of varnish with its light exit opening first. In this case, a very smooth surface of the parabloidshaped sections 3, 4, 5 and 6 of the reflector 2 is produced for the reflecting layer to be vapour deposited. Furthermore, there is no depression on the reflector as a result of the ventilating system and no contact surfaces 10 for the bulb socket 9 on which accumulation of varnish can occur.

Claims

1. A ventilated headlamp for vehicles having a reflector produced by an injectionmoulding or die-casting process with a stepped back face as a result of sections with different parabloids, and the headlamp interior, bounded by the reflector and a lamp glass or lens, being sealed off from the environment at least with regard to dirt and water spray, a groove for the ventilation of the interior being provided in a ring surrounding a bulb-receiving opening in the reflector, said groove having a trough-shaped cross-section open towards the rear and being covered by a sealing cover, said ring surrounding the reflector opening at the apex of the reflector being made integral with the bulb socket and resting on a surface formed by an extension of the reflector, the bulb socket comprising, at one end, an internal flange to support a lamp plate of the bulb and at its other end, an external flange which forms the groove which is U-shaped in cross-section.

2. A vehicle headlamp as claimed in Claim 1, wherein the sealing cover shutting off the trough-shaped groove comprises a seal pressed into the groove with a press fit

3. A vehicle headlamp as claimd in Claim 1 or Claim 2, wherein the bulb socket is stuck to the reflector in a sealed manner at a marginal region of the opening forming said extension of the reflector.

4. A vehicle headlamp as claimed in any one of claims 1 to 3, wherein the covering screen of the bulb is secured directly to the bulb socket.

5. A ventilated vehicle headlamp, with a moulded or cast reflector having a stepped rear face, the lamp interior bounded by the reflector and a front glass or lens being sealed off from the environment at least with regard to dirt and water spray, and wherein an opening in the reflector for a lamp bulb is surrounded by a ring integral with a holder or socket for the bulb, the ring resting on a rearwards extension of the reflector, the bulb socket comprising, at one end, an internal flange to support a lamp plate of the bulb, and at its other end, an external flange which forms a groove for ventilation of the interior, said groove having a rearwardly open crosssection and being covered by a sealing cover.

6. A ventilated vehicle headlamp constructed and arranged for use and operation substantially as described herein with reference to the accompanying drawings.