Device for mounting a light unit on an automobile body

A device mounting an automobile body to a light unit which is provided with a housing connected either directly or by a support frame to the automobile body. The combination of undercut hollow spaces and anchoring protrusions extending into these spaces which are then filled with a hardened flexible plastic material to anchor the protrusions in the spaces.

BACKGROUND OF THE INVENTION 
The invention relates to a device for mounting a light unit on an 
automobile body. The housing of the light unit is either connected 
directly to the automobile body or by means of a support frame. The term 
"automobile body" as used herein is intended to encompass automobile body 
parts such as front or rear parts on which the light unit is to be mounted 
and which in turn is mounted on the automobile body. These automobile body 
parts may be of sheet metal, but the current trend is to make then in 
increasing numbers from plastic materials (for example "Soft-Nose"), so as 
to survive light accidents without permanent deformation. 
Therefore, the mounting of head lamps on the automobile body was performed 
exclusively by means of screws with washers and nuts, as well as by means 
of spring yokes. In this fashion, a flexible mounting of the head lamp 
within defined limits is obtained, and, in particular, for dampening road 
shocks, which considerably shorten the life of the incandescent lamps. 
This type of mounting is relatively expensive, and, above all, the 
mounting cannot be performed fully automatically. The screws, washers and 
nuts are loose parts and accordingly there is considerable wastage and 
loss of such parts during the mounting procedure. Moreover, the ever 
present danger exists that wrong screws are used accidentally in view of 
the large number of different screws which are available and which are 
being used during the assembly of the motor vehicle. Needless to say, 
wrong screws may not be suitable for a safe mounting of the headlamps. In 
order to prevent these disadvantages, it has been proposed in DE-OS-No. 30 
30 427 to mount a light device on the front part of the vehicle by means 
of a locking connection. However, in practice this proposal is not 
practical, since tolerances of a few mm occur during the automobile body 
assembly, which cannot be accommodated by such a locking connection. 
Moreover, the various deformations occuring in the automobile body during 
operation make such a locking connection problematic. Finally, a flexible 
mounting with such a connection is difficult to adjust. 
SUMMARY OF THE INVENTION 
It is therefore an object of the invention to provide a device for mounting 
a light unit on a motor vehicle body, which mounting can be fully 
automated, does not require any loose parts, such as screws, nuts and 
washers, is cost effective, enables and causes a large tolerance 
compensation in each direction, and dampens road shocks transmitted to the 
light device without creating so-called "dancing" light. 
During the assembly of the light unit, the housing or support frame is 
aligned and fixed in position by customary means, whereby means having 
anchoring protrusions are mounted on one part to extend into undercut 
hollow spaces of the other part. Thereafter, plastic is automatically 
injected into the hollow spaces by means of customary injection molding 
guns. The plastic material possesses certain but variable flexibility 
after hardening. A foam plastic has been shown to be particularly 
advantageous as for example, plastic for foaming in window frames. Since a 
relatively large distance may exist between the wall of the hollow space 
and the anchoring protrusion, in practice finishing tolerances which may 
be as much as 10 mm in automobile bodies can be easily compensated. In the 
case of repair, this connection can be removed in a simple manner by 
melting the plastic with a thermo probe. 
The hollow spaces are preferably cup-shaped recesses. The inner peripheral 
wall defining the spaces include radially inwardly extending protrusions, 
preferably in the form of radially inwardly extending ribs. Alternatively, 
the hollow spaces may also have a trapezoidal cross-section. 
The anchoring protrusions are preferably cup-shaped and their bottoms have 
a central opening. This form of protrusion is relatively simply formed 
from sheet metal by a stamping operation. Naturally, these protrusions may 
also be made separately stamped sheet metal parts which may then be welded 
on the corresponding locations of the automobile body.

DETAILED DESCRIPTION 
The front structure of a motor vehicle automobile body 1 is illustrated in 
FIG. 1 and includes cutouts or recesses 2 and 3 for receiving in each a 
light unit. The right light unit 4 of FIG. 1 is shown as a support frame 
double head lamp and the left light unit 5 is shown as a housing head 
lamp. The light unit 4 is provided with two built-in head lamps 6 which is 
adjustably mounted in a support frame 7 which is mounted in the cutout 2 
on the automobile body 1. The reflector together with the incandescent 
bulb is adjustably mounted in a housing 8 of light unit 5, which in turn 
is mounted in cut out 3 on the automobile body 1. 
The arrangement and the installation of the support frame double head lamp 
4 in the automobile cutout 2 is illustrated on an enlarged scale in FIG. 
2. The support frame 7 is provided with upper extensions 9 and lower 
extension 10 to facilitate mounting the frame 7 in recess 2 of the 
automobile body 1. The mounting location on the automobile body for 
extension 9 are designated with the reference numeral 11 and the mounting 
location for extensions 10 are designated with the reference numeral 12. 
In contrast to the customary mounting of the light units on the automobile 
body by means of screw and nuts, the connection of this invention deploys 
a flexible, hardenable plastic-liked polyurethane foam. Exemplified 
embodiments of these connections are illustrated in FIGS. 3 to 5. The 
mounting of the extensions 9 on the locations 11 of the automobile body 1 
may be accomplished, for example, in the manner illustrated in FIG. 3. As 
will be seen, the extension 9 is provided with a hollow space 13 of 
circular cross-section. The inner peripheral wall of the space 13 includes 
a radially inwardly extending rib 14, so that an undercut hollow space is 
defined. A cup-shaped protrusion 16 is stamped out of the automobile body 
sheet metal 15 at the locations 11 in FIG. 2. The bottom of the protrusion 
16 has a central opening 18 extending into the hollow space 13. The 
protrusion 16 is encompassed by an annular shoulder 19 which is engaged by 
the upper side of extension 9. The hollow space 13 and the inner space of 
the protrusion 16 are filled with a hardenable flexible plastic 20, for 
example, polyurethane foam, so that the protrusion 16 is embedded in the 
plastic. Thus, a positive but flexible connection is provided between the 
extension 9 and the automobile body sheet metal 15 by the undercuts which 
are formed by the rib 14, on the one hand, and by the flange 17 of 
protrusion 16 on the other hand. 
The mounting of the extensions 10 of support frame 7 on the locations 12 of 
the automobile body may be performed in a manner illustrated in FIG. 4. 
The principal of mounting is the same as in FIG. 3, with the only 
difference being that a cup-shaped element 21 is welded on the automobile 
body sheet metal 15a. The cup-shaped element 21 includes a bottom flange 
22 having a central opening 23 and which is also provided with an annular 
shoulder 24 the rear side of which engages the extension 10. The extension 
10 is provided with a hollow space 25 (similar to exemplified embodiment 
of FIG. 3) into which a rib 27 extends and whose bottom 28 has an opening 
29. The hollow space 25 and also the inner space of the cup-shaped element 
21 is filled with hardenable flexible plastic 26 which forms a positive 
but flexible connection between the extension 10 and the sheet metal 15a 
of the automobile body in view of the undercuts formed by the rib 27 in 
hollow space 25 and the bottom flange 22 of the cup-shaped element 21. 
During the assembly of the light unit 4, it is initially positioned by 
means of an assembly gauge in undercut 2 of the automobile body 1. The 
cup-shaped protrusions 16 are located in the hollow spaces 13 and the 
cup-shaped elements 21 in the hollow spaces 25. Thereafter, plastic is 
injected by means of an injection gun through the protrusions 16 and the 
openings 18 into the hollow spaces 13, on the one hand, and through the 
openings 29 into the hollow spaces 25 and through the openings 23 into the 
inner spaces of the cup-shaped elements 21, on the other hand, until the 
spaces and recesses are filled completely with plastic, as can be seen 
from FIGS. 3 and 4. After the hardening of the plastic, the support frame 
7 is fixedly connected with the head lamps 6, but is fixedly connected 
with the automobile body. 
The exemplified embodiment in accordance with FIG. 5 corresponds 
substantially to the exemplified embodiment in accordance with FIG. 3 with 
the difference that the hollow space 13' has a trapezoidal cross-section. 
In the illustrated exemplified embodiments the support frame 7 is made of 
plastic and the automobile body is made from sheet metal. However, both 
parts may be made from the same material or the automobile body may be 
made from plastic and the support frame from sheet metal. 
The mounting of the light unit 5, which is shown as a housing head lamp in 
the undercut 3 of the front part of the automobile body, can be performed 
in the same manner as described in conjunction with the mounting of the 
light unit 4. In this regard, the head lamp housing 8 is provided with 
undercut hollow spaces 13 or 25 into which the cup-shaped protrusions 16 
or 21 extend. Which of the embodiments of FIGS. 3 and 4 is used for any 
application depends on the accessibility for deployment of the injection 
guns. It is important that the cross-sections of the hollow spaces and the 
protrusions extending therein are so designed that a positive connection 
is made between the parts by the injected and hardened plastic. 
Naturally many modifications of the illustrated exemplified embodiments are 
feasible without departing from the spirit of the invention.