GB1394411A - Vehicle headlamps - Google Patents

Abstract

1394411 Vehicle headlamp WESTFALISCHE METALL INDUSTRIE KG HUECK & CO 7 May 1973 [8 May 1972 12 July 1972 14 July 1972 25 Jan 1973 12 Feb 1973] 21693/73 Heading F4R A vehicle headlamp has an internal space which is in communication with the exterior through a moisture adsorbing element. In an embodiment an adsorbing element 6 containing silica gel, a molecular sieve or a zeolite in a tube 21 is fitted into member 10 which seals off the neck 5 of the reflector 1. The tube 21 connects to an annular groove 12 in the member 10 and the groove has an opening 18 for air to enter or leave the interior of the headlamp. The cap 13 has a bayonet fitting to the member 10 which may have a hole 17 in it or may be sufficiently loose to allow air to flow between it and the member 10. The tube 21 has a porous ceramic plug 16 which acts as a diffusion damper and a throttling device to prevent rapid passage of air through the element 6. In other embodiments the mask 22 is not connected to the tube 21, the porous ceramic plug 16 is replaced by a tube filled with metal or plastic filaments (28, Fig. 4, not shown) and the element 6 may be cranked or inclined towards the light source 4. In another embodiment, the diffusion damper and throttling device are provided by a tortuous passage through a cover (8, Fig. 1, not shown) on the outside of the reflector. The arrangement of the element 6 above the light source allows the source to heat up the element so that any air expelled from the headlamp removes moisture from the element whilst the throttling device prevents air from being expelled until pressure has built up in the lamp and also the element is thoroughly warm. In one embodiment (Fig. 4) a long tube 21 is used for the element so that part of it is hot and part cool.