Illumination – Light source and modifier – With ventilating – cooling or heat insulating means
Patent
1996-04-08
1997-12-30
Husar, Stephen F.
Illumination
Light source and modifier
With ventilating, cooling or heat insulating means
362373, F21V 2900
Patent
active
057021783
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lamp assembly and is particularly, but not exclusively, concerned with a motor vehicle headlamp.
2. Description of the Related Art
It is now common practice to provide vehicle lamp assemblies with a ventilation passage which provides communication between the interior of a housing of the lamp assembly and the exterior. Such a ventilation passage is designed to reduce condensation within the housing and to limit ingress of water. A vehicle headlamp assembly having a ventilation passage is disclosed in GB-A-2237626 where a housing contains a reflector and a light source. The interior of the housing communicates with the exterior via a ventilation passage which is of labyrinth form and which is defined by a tubular appendix extending outwardly from the housing and by a cup-shaped cap fitted to the free end of the appendix. The tubular appendix is split longitudinally by a transverse dividing wall so as to define two separate chambers. The tubular appendix has a slot in its side wall opening into one of the chambers, whilst the other chamber opens into the interior of the housing. The cup-shaped cap partly closes the longitudinal opening. However, under tests which are intended to replicate severe operating conditions in practice, a water spray is directed at the lamp assembly through large angles of arc. And at the same time the lamp assembly is switched on and off, thereby creating a pressure differential between the interior and the exterior of the housing. Results indicate that water can collect in the outer chamber of the labyrinth to such an extent that the water can be sucked into the housing when the internal pressure reduces at the time when the lamp is switched off.
SUMMARY OF THE INVENTION
It is an object of the present invention to obviate or mitigate this disadvantage.
According to the present invention, there is provided a lamp assembly comprising a housing in which a light source is located in use and having a light transmitting cover, and a ventilation passage providing communication between the interior and the exterior of the housing, said ventilation passage being defined by a tubular portion extending from the housing and by a cap mounted on the tubular portion, wherein the tubular portion has a continuous side wall and the cap is mounted on the tubular portion so that an end wall of the cap is spaced outwardly of a housing-remote end of the tubular portion and is joined to mutually spaced lateral walls of the cap whereby there is defined a downwardly opening slot forming part of the ventilation passage, and wherein the end wall of the cap projects downwardly beyond lower edges of the lateral walls of the cap.
Most preferably, a lower edge region of the end wall of the cap is chamfered on at least one surface thereof.
Preferably, the chamfering is on the external surface of the end wall, i.e, the surface opposite to that which lies within the ventilation passage.
The degree of chamfer is preferably such that the thickness of the end wall of the cap at the lower edge thereof is less than or equal to 50% of the thickness of the remainder of the end wall.
Preferably, the lateral walls of the cap extend forwardly from the end wall of the cap so as to overtap the side wall of the tubular portion.
More preferably, the lateral walls extend over the entire length of the cap.
Conveniently, the housing-remote end of the peripheral wall of the tubular portion is also externally chamfered.
Most conveniently, the internal surface of the end wall of the cap is planar.
In order to reduce further the risk of spray water entering the housing, the lamp assembly may also include a shield which is fixed relative to the tubular portion and the cap so that a lower surface of the shield is disposed in spaced relationship below the lower opening of the slot and projects rearwardly beyond the end wall of the cap.
The terms "downwardly" and "rearwardly" as used herein refer to the arrangement when the lamp assembly is in an orienta
REFERENCES:
patent: 4405974 (1983-09-01), Quiogue
patent: 5010453 (1991-04-01), Ketteraman
patent: 5367438 (1994-11-01), Deslandres
patent: 5388037 (1995-02-01), Umeda et al.
patent: 5562337 (1996-10-01), Takinami et al.
Monk John Frederick
Smith Alan Keith
Tolley Robert Frank
Husar Stephen F.
Magneti Marelli UK Limited
Raab Sara Sachie
LandOfFree
Lamp assembly comprising a ventilation passage does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lamp assembly comprising a ventilation passage, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lamp assembly comprising a ventilation passage will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-196380