Stock material or miscellaneous articles – Sheet including cover or casing – Foamed or expanded material encased
Reexamination Certificate
2000-02-10
2001-08-28
Thomas, Alexander S. (Department: 1772)
Stock material or miscellaneous articles
Sheet including cover or casing
Foamed or expanded material encased
C428S133000, C428S138000
Reexamination Certificate
active
06280816
ABSTRACT:
This invention relates generally to automotive interior trim components of the type having an outer pliable skin, a rigid backing panel, and a foam core in a space therebetween generated by injecting foam precursors into the space through a foam entry hole in the backing panel whereupon it commences to expand and fill the space with foam.
BACKGROUND OF THE INVENTION
In the manufacture of many interior automotive trim products, such as a door cover for a passenger supplemental inflatable restraint (PSIR) airbag system, glove and console compartment doors, door panels and instrument panels, and the like, a flexible skin or shell is placed in the cavity of the foam injection mold and a rigid insert backing panel is supported within the mold cavity above the skin to enclose and define a space for foam between the skin and backing panel. The backing panel is formed with a foam entry hole aligned with a pour hole of the upper mold part to provide an opening for the injection of foam precursors into the space whereupon they react and expand to fill the space and generate a foam core therein. In most applications, the spacing between the skin layer and the opposing interior surface of the backing panel is generally uniform resulting in a foam core that is of generally uniform density. However, in the region of the foam entry hole, there is no support to back up the foam during its expansion and as a consequence the foam in this region develops to a lower density than the immediate surrounding foam. This variation in density is particularly problematic in applications such as airbag doors which have a very thin cross section (on the order of 8 mm or less in thickness). In such instances, the relatively less dense foam in the region of the foam entry hole shows through on the outer class A surface of the skin as a depression or a soft spot that is more easily depressed than the surrounding areas of the airbag door.
It is current practice to form such foam entry holes by stamping out or molding a pair of adjacent semi-circular openings in the panel to provide a thin web or bridge between the openings that serves in some applications as a locking connection for the foam injection tool. Such construction is shown, for example, in U.S. Pat. No. 4,784,366, commonly owned by the assignee of the present invention. The foam in these open pour hole regions is less dense than that of the surrounding foam producing the sunken or soft spots mentioned above in the finished product.
SUMMARY OF THE INVENTION AND ADVANTAGES
According to the invention, an improved manufacturing process is provided for making an automotive interior trim component having an outer pliable skin bonded to a foam layer and a rigid backing panel, in which the skin and panel are supported in a cavity of a foam mold tool to provide a foam space between the skin and panel and foam precursors are poured into the foam space through a foam entry hole of the panel whereupon the precursors expand to fill the space and cure to generate the foam layer therein. The improvement comprises providing supplemental foam backing structure supported by the panel and extending across the foam entry hole to provide a supportive backing surface to the foam precursors in that region to control the density of the resultant foam in the foam entry hole region.
According to a particularly preferred embodiment of the invention, the foam entry hole is produced by punching tab portions in the backing panel as described above and then deforming the tab portions out of the general plane of the backing panel so they extend into the foam space to provide backing structure for the foam as it expands and cures in the foam space. Such provides a very simple, economical way to eliminate the sunken or soft spot regions that result from an open foam entry hole and without making significant modifications to the standard molding practice. A similar tab arrangement can be employed with a plastics backing panel, in which case the panel and tabs may be injection molded as a single piece.
According to another embodiment, the panel is molded from a rigid plastics material and at least a portion of the foam entry hole is formed by providing a pair of generally arcuate slots in the panel. Each slot defines an opening and also defines a unitary tab that integrally extends across and generally closes one of the openings in a closed position. A living hinge is formed across each tab. At least a portion of each tab is outwardly pivotable about its respective living hinge to an open position under the force of foam precursor injection. The hinges are sufficiently resilient to return the pivotable portions of the tabs to a position at least approximating the closed position.
According to another embodiment, a separate deflector piece is formed having leg portions of the same general configuration as that of the tabs attached to the web between the semicircular openings in the panel of a conventional foam entry hole such that the legs extend into the same general manner as the integrated tab portions to control the density of the foam that develops in the foam entry hole region.
According to still another aspect of the invention, an automotive interior trim panel assembly is provided having a rigid backing panel and an outer pliable skin overlying the panel and defining a foam space therebetween that is occupied by a foam core produced by injecting foam precursors into the foam space where they expand and fill the foam space to generate the foam core. Supplemental foam backing structure is supported by the backing panel within the foam space at least partially across the foam entry hole to provide a rigid support backing for the foam as it expands in the region of the pour hole in order to control its density.
According to another embodiment, the entry hole comprises at least one opening in the panel. The supplemental foam backing structure comprises a plastics material and includes at least one tab member extending from an edge of the opening across the opening. The tab generally closes the opening in a closed position. The tab includes a living hinge that extends across a width of the tab. At least a portion of the tab is outwardly pivotable about the living hinge to an open position under the force of foam precursor injection. The hinge is sufficiently resilient to return the pivotable portion of the tab to a position at least approximating the closed position.
According to another aspect of the invention, the entry hole comprises an adjacent pair of the openings separated by a partitioning web of the panel. The supplemental foam backing structure comprises a pair of the tab members that extend from the partitioning web across the respective openings and close the respective openings in respective closed positions. Each tab includes a living hinge that extends across a width of each the tab. At least a portion of each tab is outwardly pivotable about its respective living hinge to an open position under the force of foam precursor injection. The tabs extend into the foam space in diverging relation to one another in the respective open positions. Each hinge is sufficiently resilient to return the pivotable portion of each tab to a position at least approximating its respective closed position.
REFERENCES:
patent: 3519523 (1970-07-01), Rodman et al.
patent: 4784366 (1988-11-01), Muller
patent: 4839118 (1989-06-01), Labrie
patent: 4892770 (1990-01-01), Labrie
patent: 4973235 (1990-11-01), Shoji
patent: 4997356 (1991-03-01), Katagiri
patent: 5011394 (1991-04-01), Katagiri et al.
patent: 5018958 (1991-05-01), Mizuno et al.
patent: 5040335 (1991-08-01), Grimes
Hayes Soloway Hennessey Grossman & Hage PC
Textron Automotive Company Inc.
Thomas Alexander S.
LandOfFree
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