This invention relates to a motor vehicle lamp which can be mounted to a body of a vehicle of a type in which an interior cavity is defined by a plastic base plate which is attachable to the body, a plastic bowl-shaped housing and a light-transmissive shield which is arranged at an opening of a side wall, or edge, of the housing, and of a type in which at least one cross member, or support web, is molded onto the base plate for supporting the interior of the housing resting thereon.
Such a motor vehicle lamp is known from German patent document DE-OS 38 36 032. In a motor vehicle lamp described and depicted in this publication, a base plate and thus also a free edge of a bowl-shaped housing have an approximately square shape so that the base plate and the housing individually, and even more so after assembly thereof, have a high warp resistance. This warp resistance is increased by having a light-transmissive shield arranged at a right angle to the base plate and formed, or molded, directly at the edge of the base plate, thus becoming a unit with the base plate. In order to further increase the warp resistance of such relatively small lamps, the thicknesses of base plates and housings could be increased without substantially increasing material costs. However, a sharp increase in cost would be incurred by increasing wall thicknesses in large lamps in which several different light sources have their own reflectors and are arranged in rows next to one another. In order to allow extremely thin wall thicknesses of base plates and housings for such lamps, while at the same time providing sufficient warp resistance, it is possible that one could strengthen lamp components with ribs. If a lamp of this type had strengthening ribs injected, or sprayed, onto an interior of a bowl-shaped housing, a material accumulation would occur at intersections between the ribs and an outer surface of the shell, so that shrinkage of the material during a cooling process thereof would cause indentations on the outside of the shell. This disadvantage does not occur if cross members, or webs, are formed, or molded, onto the base plate, as depicted in German patent document DE-OS 38 36 032. In this regard, the cross member, or support bar, is made with double walls and is arranged along the edge of the base plate. However, this embodiment and this location of the cross member cannot always be realized, particularly in those instances when lamps are shaped to be very flat, or slim, along their edges. Usually single-walled and thin support cross members for the base plate have to be arranged in great numbers and crossing, if possible, in order to exhibit a warp-resistance effect. However, this is not possible in most lamps because of space constraints.
It is an object of this invention to reinforce not only the base plates by means of cross members, but also the housings in such motor-vehicle lamps which vary substantially in length and width and which have thin housing and base-plate walls, without requiring that additional cross members be injected onto the housings, yet still allowing for the changing of light bulbs.