GB2242513A

GB2242513A - A ventilated vehicle lamp

Info

Publication number: GB2242513A
Application number: GB9104755A
Authority: GB
Inventors: Christian Lespinats
Original assignee: Valeo Vision SAS
Current assignee: Valeo Vision SAS
Priority date: 1990-03-30
Filing date: 1991-03-06
Publication date: 1991-10-02
Anticipated expiration: 2011-03-06
Also published as: ES2025505A6; GB9104755D0; GB2242513B; FR2660413A1; FR2660413B1

Abstract

A ventilated illuminating or indicating appliance for a vehicle, such as a headlamp or indicating lamp, includes a ventilation channel (102) in which a filter (107) is arranged, the filter being made of a foam of open-pored reticulated plastics material, in which the walls of the cavities constituting the pores have been destroyed during reticulation in such a way as to leave in place only edge portions of the cavities. <IMAGE>

Description

A VENTILATED ILLUMINATING OR INDICATING APPLIANCE FOR AN AUTOMOTIVE VEHICLE, FOR EXAMPLE A HEADLAMP OR INDICATING LAMP This invention relates to a ventilated illuminating or signalling appliance for an automotive vehicle, such as a headlamp, driving lamp, fog lamp or indicating lamp.

It is conventional to make such appliances such that they are fully sealed. However, apart from the fact that this involves using particular sealing elements which are specifically designed for each application, perfect sealing does not generally continue to exist over the passage of time, because of the severe forces to which the lamp will usually b subjected in use, and in particular due to the fact that heating and cool ins cycles occur respectively when the lamp is illuminated and when it is extinguished.

Failure of sealing leads generally to the presence of humidity inside the appliance, and this causes droplets of condensation to form within it. This in turn leads to deterioration in the quality of the light beam emitted by the appliance, and also leads to chemical deterioration of the various components of the appliance.

In seeking perfect sealing, the very opposite of the result looked for tends to be achieved in practice, since while the entry of humid air is not prevented, the evacuation of the resulting humidity is either prevented or at least hindered.

Those solutions which have been said to be the most effective for avoiding the appearance or persistence of condensation in illuminating or indicating appliances consist in providing controlled ventilation means which enable the air to be changed between the interior space of the appliance and the outside, while preventing the penetration of solid or liquid matter.

Various types of solution of this kind have been proposed.

In particular, the document FR 2 183 934A describes the use of a sinuous tube, within which an element is provided which is permeable to air, and which captures humidity by adsorptio. Document FR 2 254 753A also discloses a sinuous arrangement the dimensions of which are predetermined in such a way as to prevent any penetration of liquid by capillary action into the interior of a headlamp.

These various types of solution have given some satisfaction, but have shown themselves to have me imperfections and a degree of ineffectiveness in the face of increasingly severe environmental conditions to which appliances of the kind under consideration now tend to be exposed. Conditions of increased severity arise from increased exposure to bad weather conditions and to projections of all kinds, of solid and liquid matter, quite apart from the effects of the use of high pressure water jets for cleaning the engine compartment of the vehicle.

An object of the present invention is to overcome the defects of known solutions.

According to the invention, there is provided a ventilated illuminating or indicating appliance for a vehicle, comprising-communication means, preferably sinuous, between the interior of the appliance and the outside, wherein the communication means comprises a ventilation channel with a filter disposed within the said channel the filter being made of a foam of open-pored, reticulated plastics material, in which the walls of the cavities constituting the pores have been destroyed during reticulation, in such a way as to leave in place only edge portions of the cavities.

The filter is preferably in the form of a plug.

Preferably the porosity of the foam is defined by a mean number of pores per centimetre lying between 9.5 and 14, being preferably in the region of 12 pores per centimetre.

The foam is preferably of polyurethane.

According to a preferred feature of the invention, the said hydrophobic filter is fitted in an upper part of a ventilation channel in such a way that the liquid droplets caught by the hydrophobic filter are allowed to escape to the outside by flowing under gravity.

The invention enables an excellent degree of variation to be obtained in an illuminating or indicating appliance which effectively prevents the penetration of liquid and/or solid elements into the interior of such an appliance, while at the same time ensuring the rapid expulsion by evaporation of any possible condensation of water vapour inside the appliance.

Further features and advantages of the invention will appear more clearly from the description which follows, in which one embodiment of the invention is described by way of example only and with reference to the accompanying drawing. By way of non-limiting example, this description is related to the headlamp which is described in the document FR 2 544 839A.

The drawing, consisting of a single Figure, shows in cross section a detail of a headlamp housing for an automotive vehicle, equipped with the filter in accordance with the invention.

The headlamp housing 1 includes (using where appropriate the same reference numerals as in the description and drawing of document FR 2 544 839A) an upper wall 2, a lower wall which is not shown here but which in document FR 2 54 839A is indicated by the reference numeral 3, and a base wall 5. Each of the side walls 4 joins the upper wall 2 to the lower wall. The base wall 5 has an outer periphery through which it is joined to each of the other four walls, together with an inner periphery which defines an access aperture 6 which gives access to the interior of the housing 1. The aperture 6 is normally closed by means of a hermetically sealing cap member, not shown.

A generally cylindrical hood 100 is positioned in the upper part of the headlamp. The hood 100 projects away from the housing 1, i.e. it is a forward projection from the base wall 5. Alternatively it may be secured to the latter, As shown, the hood 100 is an extension of the upper wall 2 beyond the base wall 5.

A hollow spigot 101 projects from the base wall 5 and is enclosed within the envelope defined by the hood 100. The spigot 101 may be integral as shown with the base wall 5, or may be a separate component secured to it. The spigot 101 plays a part in defining a ventilation channel 102 between the interior of the housing 1 and the outside. As shown in the drawing, the hollow spigot 101 is formed in moulding the base wall 5. The hollow spigot 101 includes a radial shoulder 103 parallel to the base wall 5.

A tube 10 is mounted on the hollow spigot 101 and abuts against the radial shoulder 103. The ventilation channel 102 is extended in the tube 104, which is preferably bent, as shown, and which is open to the outside through an orifice 105 at its other end which is directed towards the base wall 5. The orifice 105 lies within the hood 100.

Preferably, and as shown in the drawing. the tube 104 is arranged entirely within the hood 100.

With this arrangement, the ventilation channel 102 is especially well protected from projections of liquid and/or solids which could affect the headlamp housing 1 when mounted on an automotive vehicle.

In addition, the ventilation -channel 102 is open within the housing 1 via a groove 106, which again, is formed in the moulding of the base wall 5. The sinuous ventilation channel whereby the interior of the housing 1 is brought into communication with the outside, as described above, is highly effective.

A plug 107, acting as a filter, is disposed within the ventilation channel 102. This plug 107 is made of a foam of reticulated plastics material with open pores.

Preferably this plastics foam is a foam of soft, reticulated polyurethane, in which the walls of the cavities which define the pores have been destroyed during the reticulation process, in such a way that only the edges of the cavities remain in place.

The porosity of the foam is preferably defined by a mean number of pores per centimetre in the range 9.5 to 14, and preferably in the region of 12 pores per centimetre. In this example, a polyurethane foam of the kind sold by the company known as Tramico under the Trade Mark TRAMOPEN and under the reference 30 PPI. is used. This has a mean porosity of 11.8 pores per centimetre (30 pores per inch). The invention enables excellent ventilation to be obtained in headlamps or other lighting or indicating appliances, while effectively preventing liquid or solid matter from penetrating into the interior of the appliance. In addition, any possible condensation of water vapour that may occur within the appliance is rapidly expelled to the outside when the headlamp or indicating lamp is illuminated.

A number of particularly severe tests have been carried out on appliances according to the invention, and have shown surprisingly, that even when the illuminating or indicating appliance is completely immersed in a liquid, the liquid does not penetrate into the appliance.

Claims

1, A ventilated illuminating or indicating appliance for a vehicle, comprising communication means, preferably sinuous, between the interior of the appliance and the outside, wherein the communication means comprises a ventilation channel with a filter disposed within the said channel, the filter being made of a foam of open-pord reticulated plastics material, in which the walls of the cavities constituting the pores have been destroyed during reticulation, in such a way as to leave in place only edge portions of the cavities.

2. An appliance according to Claim 1, wherein the said filter is in the form of a plug.

3. An appliance according to Claim 1 or Claim 2, wherein the said foam of plastics material is of polyurethane.

4. An appliance according to any one of the preceding Claims, wherein the porosity of the foam is defined by a mean number of pores per centimetre lying between 9.5 and 14, being preferably in the region of 12 pores per centimetre.

5. An appliance according to any one of the preceding Claims, comprising a housing having an upper wall and a base wall, wherein a generally cylindrical hood projects from the outer face of the base wall away from the housing, with the communication means being contained within the envelope defined by the hood.

6. An appliance according to Claim 5, wherein the communication means comprise a hollow spigot consituting part of the ventilation channel between the interior of the housing and the outside.

7. An appliance according to Claim 6, wherein the communication means includes a bent tube open to the outside through an orifice which is directed towards the base wall, and which is open within the hood.

8. An appliance according to Claim 6 or Claim 7 when -dependent on Claim 2, wherein the said hydrophobic filter plug is fitted into the said ventilation channel.

9. An appliance according to any one of the preceding Claims, wherein the communication means is open within the housing via a groove.

10. An appliance according to any one of Claims 5 to 8, wherein the said hood is formed by moulding with the said base wall and constitutes an extension of the upper wall of the housing.

11. An appliance according to Claims 6 and 9, wherein the said spigot and groove are formed by moulding with the base wall.

19. A ventilated illuminating or indicating appliance for a vehicle, according to Claim 1 and substantially as described in the foregoing description with reference to the accompanying drawing.