Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reexamination Certificate
1998-09-10
2002-07-02
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C264S255000, C264S267000, C264S278000, C264S328700, C264S328800, C425S127000, C425S129100
Reexamination Certificate
active
06413460
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method of manufacturing a partially covered panel. More specifically, the invention is directed to manufacturing a panel having a covering that covers less than the entire surface of a panel by integrally forming the covering into the panel.
2. Description of the Related Arts
It is known to manufacture panels that display more than one surface material. This is especially useful in automotive interiors such as instrument panels, door trims and center consoles. In these applications, one surface may be formed to have a soft textured surface that is commonly formed from a foam-backed vinyl or urethane covering. The covering is thermoformed into the rough shape of the part and is then secured to a rigid panel. In this way, the panel has an area bounded by the covering that displays an area having a soft texture and another uncovered area that displays the rigid substrate. It was difficult and costly to secure the covering to the substrate and various methods have been proposed to form the covering and substrate in a single molding operation.
Japanese patent application 7-276421, published Oct. 24, 1995, teaches an injection molding method of securing a covering to a substrate to manufacture an automotive instrument panel. A covering is thermoformed to have the shape of the panel and placed within a mold. The covering has a foam inner layer and a “heat fusion layer” at the innermost surface. Molten plastic is injected against the covering to form the panel. The plastic is first injected against the covering and after it passes over the edge of the covering, different areas of the mold inject additional quantities of plastic. The plastic streams meet and weld together in a region beyond the covering. By injecting a first quantity of plastic directly behind the covering that flows over the perimeter, the edge of the covering is not lifted or displaced in the injection molding process. The process described in the 7-276421 patent application forms a seam on the same plane between the plastic and the covering. The perimeter edge of the covering forms the boundary between the rigid plastic and the covering. If the edge is ragged or if the covering is out of alignment, it is visible and displays the flaw. Additionally, the plastic streams meet in an area beyond the perimeter of the covering. The location where two plastic streams meet is called a knit line. Knit lines are often visible and detract from the appearance of the decorative surface. It is desirable to provide a method that is not as sensitive to the placement and dimension of the covering. It is also desirable to provide a method that conceals the knit lines of the plastic article.
U.S. Pat. No. 5,429,786, is also directed to a method of manufacturing a partially covered panel. The U.S. Pat. No. 5,429,786 teaches a compression molding method of forming a panel. In compression molding, a quantity of molten plastic is placed between two open or partially open molds. The molds are brought together to compress the plastic between the molds. The pressure of compression molding is generally much lower than the pressure of injection molding and lighter tools are possible.
In the U S. Pat. No. 5,429,786, a covering having a perimeter flange portion is placed within a recess of a mold. A quantity of molten plastic is placed adjacent to the covering and the molds are closed. The action of closing the molds causes the plastic to flow over the covering flange portion. The flange portion acts to conceal the periphery of the covering within a groove in the finished panel. In the embodiment illustrated in
FIG. 10
, a fence is used, but the fence does not engage the flange portion or retain the covering in the mold prior to or during molding. The method described in the U.S. Pat. No. 5,429,786 selected compression molding plastic behind the covering in place of injection molding to avoid excessive compression of the foam layer of the skin sheet or production crimps on the skin sheet. While compression molding has the advantage of applying less displacing or crimping force on the covering, it significantly lengthens the cycle time of each molding operation when compared to injection molding. It is desirable to provide an injection molding process as described in the Japanese patent application 7-276421 while retaining the flange portion described in the U.S. Pat. No. 5,429,786. This would combine the high-speed nature of injection molding together with the placement option and seam concealing features of the compression process.
These and other disadvantages of the related art are overcome by the methods taught by the present invention.
SUMMARY OF THE INVENTION
The present invention is directed to a method of producing a partially covered panel comprising a series of manufacturing steps. A covering is formed to have a perimeter portion. The covering is generally formed using a thermoforming operation. The perimeter portion is formed into a flange-shape. A mold movable between an open and closed position is moved to an open position. The mold includes a first and second surface. The covering is placed juxtaposed the first surface. A retainer is extended to retain the covering in position prior to and during the molding operation. The retainer engages the perimeter flange portion of the covering. The mold is moved to the closed position. The retainer, covering and first surface define a first cavity section. A first quantity of molten plastic is injected under pressure into this first cavity section. The molten plastic pushes the flange portion against the retainer and prevents the seepage of plastic between the first surface and the covering.
After the first cavity is filled, the retainer is retracted and a second quantity of molten plastic is injected into the mold. The second quantity of plastic surrounds the first cavity and forms the partially covered panel. The panel displaces at least two distinct surfaces. One surface comprises the covering and another surface displays the solidified second quantity of plastic.
These and other objects, features, and advantages of the present invention will become more readily apparent when viewed in connection with the accompanying drawings wherein like reference numbers correspond to like components.
REFERENCES:
patent: 5429786 (1995-07-01), Jogan et al.
patent: 5759464 (1998-06-01), Matsumoto et al.
patent: 6004498 (1999-12-01), Fujii et al.
patent: 6054087 (2000-04-01), Noirot et al.
patent: 7-276421 (1995-10-01), None
patent: 7-276422 (1995-10-01), None
patent: 7-276425 (1995-10-01), None
patent: 7-290499 (1995-11-01), None
Berry Charles Luke
Homburg Frederick J.
Nichols Calvin Columbus
Suryanarayan Talavane
Wagner Hazel
Lee Edmund H.
Shelton Larry I.
Silbaugh Jan H.
Visteon Global Technologies Inc.
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