Method of forming a gasket for automotive lamps

Details Method of forming a gasket for automotive lamps Method of forming a gasket for automotive lamps

1999-01-25

2001-06-05

Kuhns, Allan R. (Department: 1732)

Plastic and nonmetallic article shaping or treating: processes

Direct application of electrical or wave energy to work

Limited to treatment of surface or coated surface

C264S046400, C264S080000, C264S134000, C264S259000, C264S271100, C264S338000

Reexamination Certificate

active

06241936

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automotive lamp in which a gasket for sealing a back side of the lamp is disposed between a lamp body and an automobile body panel so that water, dusts and the like are prevented from entering the back side of the lamp where wires connecting to a lamp bulb or the other electrical equipment are arranged.
2. Related Art
FIG. 5
is a vertical sectional view showing a conventional automotive lamp of the type as disclosed, for example, in Unexamined Japanese Patent Publication No. Hei. 3-15748. The conventional automotive lamp shown in
FIG. 5
includes a lamp body
1
which is formed on a back wall thereof with a seal leg
2
projecting therefrom for surrounding a bulb insertion hole
2
and a gasket
8
disposed between the seal leg
2
and an automobile body panel
6
. Both a front and a rear side of the gasket
8
have a respective high adhesive surface so that the gasket
8
sticks both to the seal leg
2
and the automobile body panel
6
. In the figure, reference numeral
3
designates a front lens and reference numeral
4
designates a lamp bulb.
FIG. 6
is a sectional view of an essential part of another conventional automotive lamp. As shown in
FIG. 6
, a gasket
8
A is formed like an endless web a cross section of which is U-shaped. An adhesive agent is applied, if desirable, to a tip end of the seal leg
2
so that the gasket
8
A sticks to the seal leg
2
.
According to the conventional gasket
8
as described above and shown in
FIG. 5
, however, since the gasket
8
is formed by cutting out a seat-like material to have a frame-shape to fit to the configuration of the tip end of the seal leg
2
, the yield rate of the material is very unsatisfactory which raises manufacturing cost.
Further, the high adhesive surfaces of the gasket
8
shown in
FIG. 5
are actually made from a double-sided adhesive tape. More specifically, the double-sided adhesive tape with a peel-off sheet on each side is attached to each the front and rear surfaces of the gasket
8
. Accordingly, during assembly of the conventional automotive lamp, when the lamp is coupled to the automobile body, the gasket
8
is disposed between the seal leg
2
and the automobile body panel
6
. First, the peel-off sheet on one side of the gasket
8
is peeled off to expose the adhesive surface, and then the adhesive surface is pressed against the seal leg
2
so that the gasket
8
sticks integrally to the seal leg
2
. Next, the peel-off sheet of the other side of the gasket
8
is peeled off, and then the lamp is coupled to the automobile body, so that the adhesive surface of the gasket
8
sticks to the automobile body panel
6
. Thus, the conventional automotive lamp requires the complicated steps during assembly, which steps takes a relatively long time. That is a problem because it raises the manufacturing cost.
On the other hand, according to the secondary conventional gasket
8
A shown in
FIG. 6
, the gasket
8
A is formed by the injection molding operation, and the cost for the mold die apparatus or the like is very high. In addition, the gasket
8
A must be attached to the seal leg
2
prior to coupling the lamp to the automobile body. This is intricate. Further, in a case where no adhesive agent is applied to the tip end of the seal leg
2
, the gasket
8
A may sometimes drop off the seal leg
2
.
SUMMARY OF THE INVENTION
The present invention was made in view of the foregoing difficulties and problems accompanying the conventional automotive lamps. Therefore, an object of the present invention is to provide an automotive lamp capable of simplifying coupling operation during assembly as well as improving the yield rate of materials for a gasket which is disposed between a seal leg and an automobile body panel.
The above and other objects can be achieved by a provision of an automotive lamp which, according to the invention, includes a lamp body, a gasket disposed between the lamp body and an automobile body panel for sealing a back side of the lamp, a seal leg projecting from the lamp body for attaching thereto the gasket, wherein the foamed gasket is molded integrally with a tip end part of the seal leg. Since the gasket is foam-molded integrally with the seal leg projecting from the lamp body and thereby in close-contact with to the seal leg, it is not necessary to adhere the gasket to the seal leg by an adhesive agent or the like.
According to another aspect of the present invention, first, a nozzle injects a material for a foamed gasket into a gasket molding groove formed in a jig, and the injected material is left to thereby foam-expand. Next, a lamp body with a seal leg facing down is operated to move downward so that the seal leg is inserted in the molding groove, and the seal leg is held against the gasket material. As a result, the surface of the gasket is solidified. Afterwards, the gasket is released from the jig together with the lamp body and the seal leg, and the gasket is left in atmosphere so that the gasket is sufficiently solidified. Thus, the gasket is molded integrally with the seal leg.
Among these steps, if desired, the step in which the nozzle injects the gasket material, the step in which the lamp body is moved down to press-fit the seal leg into the foamed gasket material filled in the molding groove, and the step in which the lamp body is lifted to release the gasket from the molding groove together with the seal leg may be automated. If these steps are automated, an operator has to merely set the lamp body on an automation line and take the lamp body which is molded integrally with the gasket out of the automated product line. Hence, mass-production can be achieved while excessively reducing the manual works.
Further, if the seal leg is subjected to surface active treatment, the gasket would hardly detach from the seal leg because of the high adhesibility of the foamed gasket to the seal leg. As a result, easy treatment of the lamp with which the gasket is integrated, improved operation for coupling the lamp to the vehicle body, and good workability when the gasket is provided can be accomplished.


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