Motor vehicle lamp assembly

Claim 1

A motor vehicle lamp assembly comprising: a lamp housing adapted to be mounted on the motor vehicle, said housing including wall means terminating with a peripheral flange mating with peripheral rim of said housing and covering said opening; a gasket between the flange and the rim; fastener means securing said lens to said housing to compressively retain the gasket between the flange and the rim to define a sealed lamp cavity containing air at substantially atmospheric pressure; first and second openings in said wall means of said housing; a lamp member carried on said housng and projecting through said first opening into said lamp cavity, said lamp member including a filament adapted to be connected to an electrical source, said filament when energized directing illumination outwardly through said lens and heating and pressurizing the contained air in said lamp cavity; and an accordion pleated bellows having an expandable chamber and a tubular flanged base with an axial passage communicating with the chamber, said bellows being directly mounted on said wall means exterior of said housing with the flanged base being press fittedly received within said second opening whereby said chamber fluidly communicating with said lamp cavity through said axial passage, said bellows expanding and contracting to vary the volume of said chamber to maintain the pressure therein substantially constant thereby preventing a pressure differential between the cavity and atmosphere tending to draw moisture into the lamp interior during cool down of the lamp assembly.