Abstract:
Plastic panels which are useful as automotive interior trim panels, interior door panels and the like decorative and structural panels, are made by a method which provides an underturned edge onto the panel. The method includes positioning blanks into a mold cavity over top of a mold ring. The blanks are secured to the mold ring and the blank is secured to the mold cavity via a vacuum. The two piece mold is mated together and a substrate is injected into the mold cavity. The cavity is opened, the ring is lifted and the formed part is removed from the mold.

Description:
BACKGROUND OF THE INVENION 
     This invention relates to a composite molded panel which may be shaped to form an interior door panel or an interior trim panel for a vehicle or to form similar types of panels used for other purposes. It is especially useful in producing vehicle interior doors and trim panels having an undercut edge. 
     Interior door panels for vehicles are typically made by first forming a preselected size and shape of foundation board made of stiff particle board, fiber board or plastic material which is commonly called a substrate. Then, one or more cloth-like sheets are fastened to the surface of the substrate. The substrate may also function to support other items, such as window regulator parts, small motors, wiring and the like, which are located upon or within the door. In many vehicles, the interior surfaces of the door panels are decoratively enhanced by adding inserts upon the panel. The inserts may be in the form of smaller sections or panels which may be formed, for example, of fabric or carpet-like sheets or sheets with heavily textured surfaces or sheets of different surface colors or material. 
     Typically, the interior door and trim panels of the type described above are assembled out of separate parts which are positioned upon the substrate and fastened together, one by one, to provide a completely assembled panel. This assembly is fastened within the metal or plastic door or within other parts of the interior of the vehicle. This technique for manufacturing interior and trim panels is relatively time consuming and expensive. Moreover, this limits the ability to significantly contour or curve the interior surface of the vehicle. For example, it is difficult to provide a curved or contoured foundation board and to cover such a curved board. Therefore, vehicle interior door surfaces are relatively flat and other trim surfaces also have limited curvatures. 
     Thus, this invention relates a plastic molding method for making interior door and trim panels and the like, which may be curved, and which have a downwardly curved undercut edge, at reduced cost and with enhanced decorative appearances. 
     SUMMARY OF THE INVENTION. 
     The invention herein contemplates molding a plastic panel by, first, preparing a thin, fabric flexible plastic sheet which is sized and shaped to form a blank. The blank is positioned within a mold. As the blank is positioned within the mold, the blank is pulled over a mold ring. Next, plastic molding material is placed within the mold and is molded, in situ, to form a relatively rigid plastic molded substrate whose exposed, outer surface, is made up of the composite of the fabric or plastic sheet blank. The blank could also include inserts of different materials and textures which are carried by the blank. Since the substrate is molded in situ within the thin fabric or plastic sheet blank, other objects may be simultaneously molded upon or within the substrate. For example, window parts, wires, ductwork and the like may be molded within the substrate. Alternatively, the substrate may be provided with integral portions that are configured to receive or to mount exterior mechanical parts or trim elements. Thus, this method may economically produce, for example, an interior door panel which may have curved portions and which carries separately mounted or integrally formed arm rests or window controls or other items mounted thereon, while providing an enhanced decorative appearance. 
     A major object of the invention is to provide an undercut or downturned edge. This is accomplished by the mold ring including a cut out portion which enables the blank to be received in the cut out portion. As the substrate is injected into the blank, the material fills in behind the blank forcing the blank into the cut out forming the downturned edge. The blank is continuous around the edge and covers the bottom of the edge. The remainder of the blank may be trimmed from the molded panel to provide an undercut on the molded panel. 
     A further object of the invention is to provide a method for rapidly and economically producing vehicle door panels and interior trim panels and the like with a minimum of labor and with better, more uniform quality than has previously been possible utilizing the typical panel assembly techniques which have been used in the past for making door interior panels and trim panels. 
     These and other objects and advantages of the present invention will become apparent upon reading the following description of which the attached drawings form a part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an automobile interior door panel which schematically illustrates a panel made in accordance with the method described herein. 
     FIG. 2 is a cross sectional view of FIG. 1 along lines  2 — 2  thereof. 
     FIG. 3 is a perspective, schematic view of a mold assembly in accordance with the present invention. 
     FIG. 4 is a cross sectional view of FIG. 3 along lines  4 — 4  thereof with the blank loaded on the ring. 
     FIG. 5 is a cross sectional view of FIG. 3 along lines  5 — 5  thereof with the blank loaded on the ring. 
     FIG. 6 is a cross sectional view of the molds in a closed position. 
     FIG. 7 is a perspective view of the molds in an open condition after forming of the part. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 schematically illustrates an example of an interior door panel  10  for an automobile. The panel  10  is illustrated as being formed with undercut edges. The panel is sized and shaped to fit within a sheet metal door for trimming the interior of the door within the passenger compartment of the vehicle. The panel may include for illustration purposes, an upper panel insert  12  which may have an interior face formed so as to simulate a wood grain appearance or may be inlaid with some other material. Similarly, a lower insert  14  is positioned in the panel and may be formed of a piled carpet-like material or fabric to simulate a carpet or fabric section of the panel or may be an inlay of some other material. 
     The panel may be provided with various openings or receptacle areas, after the molding is completed, to receive some of the hardware which is typically mounted within a vehicle door. These openings or areas may be cut or punched into the panel. For example, the panel may have a square or oblong opening  16  to receive a block of switches which operate the window actuating motors, and a second round opening  18  which may receive switch for actuating the exterior side view mirrors. Different sized and shaped opening and receptacle areas may be molded in the panel as required. 
     The interior surface  20  of the panel may include embossments or may be textured. These decorated surface configurations may be formed during the molding of the panel door or may be preformed in the sheet or blank utilized in the molding. 
     As better illustrated in FIG. 2, the edge  22  of the panel  10  is undercut. The blank which is utilized to form the interior surface  20  is continuous around the edge  22 , on the panel  10 . The molding process begins with being provided with a blank  30  to be positioned into the mold cavity. The blank  30  may be formed by methods like those disclosed in U.S. Pat. No. 5,091,031, issued Feb. 25, 1992, the specification and drawings of which are herein expressly incorporated by reference. The blank  30  may include inserts or it may be a continuous sheet of material. 
     The blank  30  is positioned into the mold cavity  32  of mold  34  on top of the ring  36 . The mold  34  is of the vacuum type, as best illustrated in FIG.  6 . Once the blank  30  is positioned into the mold cavity  32  on the insert  33 , the vacuum is activated around the insert  33 , securing the blank onto the mold  34 . The outer periphery of the blank is then secured onto the ring  36  via pins  40 . The periphery of the blank  30  is pulled down on top of the pins  40  and is secured thereto. 
     The ring  36  is secured to the female mold via plates  42  and  44  which are secured to a hinge  46 . Thus, the hinge  46  enables the ring  36  to be positioned within the cavity and to be rotated out of the cavity for removal of the panel. 
     As can be seen in FIGS. 4 and 5, the ring  36  includes a cut out portion  50 . The cut out portion  50  has a terminal end  52  which forms the edge of the panel  10 . As can be seen in the drawings, the blank  30  is drawn into the cutout to form the undercut on the panel. 
     After the periphery of the blank  30  is secured to the ring  36 , the top mold  60  is closed onto the ring and bottom mold  34 . As can be seen in FIG. 6, the substrate is injected through the mold  60  and into the mold cavity  34 . Generally, polyurethane or any other plastic material or the like is utilized as the substrate and is injected into the mold cavity. The substrate is then allowed to cool in the cavity for a desired period of time. After the substrate has cured and cooled, the top mold  60  is opened. After opening of the mold, the periphery of the blank  30  is removed from the ring  36  and pins  40 . The ring is then moved upward away from the mold  32  and the panel  10  is removed from the ring  36 . Upon removal of the panel  10 , generally the peripheral blank is cut or removed from the panel to form a finished panel. Thus, by utilizing the ring  36  with its cutout portion, an undercut can be formed at the panel edge. 
     If necessary, prior to adding the substrate, wiring switches or the like would be positioned onto the mold  60 . If such a positioning of the elements is not necessary, the blank would be in a position like that shown in FIG.  6 . At this position, the molds are mated together. The mold  60  fits into the mold  34  such that there is a gap between the blank and the mold  60 . The mold  60  also includes a bore to enable passage of the substrate into cavity  32 . If a second layer of less dense foam backing is required, it could be added prior to the substrate either by injection through the male mold or by spraying it onto the blank. 
     A suitable plastic material is injected into the mold cavity for injection molding the panel substrate therein. The injected plastic material solidifies in the cavity. Alternately, expandable plastic beads may be inserted into the mold cavity, either through the passageway or it may be placed in the cavity before the mold is closed. The application of suitable heat for the necessary time causes the expandable beads to mold the substrate and to seal it within the cavity. After the plastic solidifies, the mold panel is removed as described above. The mold panel substrate may include integral part such as molded brackets, bosses and other separate parts positioned in the interior of the mold cavity. The passage ways or openings or receptacles may also be formed in the panel during molding. By way of an example, an electric motor for operating the windows, or part of a window regulator mechanism or wires or switches or heating/air conditioning channels or the like may be positioned in the panels during molding, as previously stated. 
     As illustrated in FIG. 6, the mold  32  has a vacuum chamber  80  formed beneath it with a hose  82  connected to a vacuum pump, not shown. Air is sucked along the insert blade  35  from the cavity surface to the vacuum chamber for positioning and registering the blank on the mold cavity. 
     The methods described above are particularly useful for molding door panels and thereby replacing conventional door panel assemblies which are made up of a number of parts that are fastened together. However, the methods are also useful in forming other types of trim panels for vehicles as well as other types of panels for other uses. For example, an interior dashboard panel may be formed with inserts of various types molded in the surface of the panel. As another example, a molded headliner may be formed for use within the upper part of the passenger compartment of a vehicle. 
     The molding methods are useful for producing panels made of a variety of materials. By way of example, the panel substrate may be formed of a substantially rigid, structural polyurethane plastic which is commercially available from various chemical companies. The particular plastic selected will depend upon the cost, availability and the ultimate use. 
     The overall molded plastic panel is waterproof. Therefore, conventional water shields that typically are utilized within vehicle doors, for protecting the trim panel from water seepage due to water entering into the door cavity, are unnecessary and eliminated. This reduces the cost of the overall door assembly considerably. 
     While the above detailed description describes the preferred embodiment of the present invention, the invention is susceptible to modification, variation, and alteration without deviating from the scope and fair meaning of the subjoined claims.