Abstract:
A method of manufacturing a rear shelf trim and speaker grill panel ( 12 ) for an automotive vehicle ( 10 ) includes steps of punching a substrate layer ( 16 ) of a polypropylene and flax material with a punch set ( 46 ) to form a grill section ( 60 ) and placing a decorative carpet layer ( 18 ) over the substrate layer ( 16 ) and molding the two layers into a combined speaker grill and rear shelf trim panel ( 12 ).

Description:
This application is a continuation-in-part of patent application U.S. Ser. No. 09/260,799 filed Mar. 1, 1999, now pending. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a method of making a rear shelf trim panel with speaker apertures to accommodate a speaker mounted under the rear shelf trim panel. 
     BACKGROUND OF THE INVENTION 
     Many motor vehicles now have FM stereo radios or more elaborate sound systems such as tape players, compact disc players, digital tapes and computer sound systems with accompanying speakers for the enjoyment of the driver and passengers. Furthermore, the electronics of the sound system have also greatly improved. As a result, of all these improvements, the sound emanating from a car stereo speaker has a quality that was unheard of only a few years ago. 
     Many after-market speakers are free standing with their own cases and speaker grills. The speaker grill is commonly used to conceal and protect the actual speaker cone against puncture or other damage. Factory mounted speakers are often mounted in concealed places such as behind door panels and under rear trim shelf panels. When the speakers are positioned behind or under such panels, the panels must incorporate a speaker grill that has apertures and cutouts to reduce muffling effects of the panels and to promote the efficiency of sound emanating from the concealed speakers into the interior of the motor vehicle. 
     Many known speaker grills are molded. Pins are used in the mold to form apertures through the cover to allow sound emanation. A porous cloth or non-woven fabric may provide a fabric covering for the speaker grill. While the panel needs holes to allow transmission of sound, a light porous cloth or fabric may cover the holes in the panel structure without an overly undesirable amount of sound blockage. 
     What is needed is an expeditious method of forming an integrated speaker grill with an automotive interior panel that has apertures incorporated therein to provide for the transmission of sound from the speaker into the automotive vehicle interior. 
     SUMMARY OF THE DISCLOSURE 
     In accordance with one aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel includes the initial step of providing a substrate layer of a heated mat material having a content.of thermoplastic material such that it is moldable under heated conditions. Preferably the mat also has a content of flax fiber. The process also includes punching a plurality of apertures in a speaker grill section of the heated substrate. The punching of the apertures is, in one embodiment; simultaneous with the molding step such that the apertures are formed through both the substrate and the decorative layer as the substrate and decorative layer are shaped into the final panel contour. 
     A decorative layer is provided onto the heated substrate. The decorative layer is preferably a porous carpet with a thermal plastic back surface. 
     The substrate and the decorative layer are molded into the desired shaped panel such as a rear shelf trim panel such that said apertures form an integrated speaker grill section within the panel. 
     Preferably, a first and second mold dies form the apertures in the substrate. The first mold die has apertures therein and the second mold die has a punch set that fits in the apertures of the first mold die to punch apertures through both the decorative layer and the substrate as the mold dies are closed to shape the substrate and the decorative layers into the panel. 
     In one embodiment, the apertures in the substrate are formed in the speaker grill section before the substrate is molded into its final shape. The grill section is positioned such that pins are then received in the apertures in the grill section and the decorative layer is positioned over the substrate, grill section and the pins in the mold. The mold is closed and the substrate layer, grill section and decorative layer are molded into a shape of an automotive interior panel under pressure. 
     In one embodiment, the speaker grill section is a separate previously formed perforated member that is placed over an opening of the substrate layer such that a peripheral edge of the perforated grill section overlaps an edge of the substrate layer about the opening. A hot melt adhesive is applied to the perforated grill section for adhesion to the decorative layer. 
     The substrate is then removed from the pins and mold. The apertures in the grill section are positioned under the decorative layer, i.e., the molded panel has the decorative layer spanning over the apertures in the grill section of the substrate. 
     Preferably, the pins extend through a first mold die and are level with an interior surface of the first mold die. The apertures in the substrate are formed by a first punch set aligned with the pins to push through the substrate and recess the pins. The punch set is then raised to remove the punched scraps of substrate. The pins are then raised to intrude into the apertures in the substrate. A second mold die that complements the first mold die is provided and the panel is molded into shape with the pins extending through the first mold die and remaining in the apertures in the substrate. 
     In accordance with another aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel is characterized by the steps of providing a decorative layer that is capable of being bonded to the substrate layer; placing the heated substrate layer and decorative layer into an open mold; closing the mold and molding the substrate layer and the decorative layer into a formed automotive interior panel under pressure between two closed mold dies with a first mold die section having a section with a plurality of holes therein and a complementary mold die section having a plurality of punches that mate with the plurality of holes to punch a plurality of apertures in the formed panel to form an integral speaker grill with the panel; and opening the mold dies and cooling the panel to be resolidified with the substrate and decorative layers being bonded together and removing the molded formed panel and speaker grill from the mold. 
     In accordance with another aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel is characterized by the steps of: providing a grill section and substrate layer of a heated mat material having a content of thermoplastic material such that it is moldable under heated conditions; punching out a plurality of apertures in the grill section; positioning said grill section such that a pin is received in each respective aperture with an end of the pin substantially coplanar with one side of the grill section; providing a decorative layer that is capable of being bonded to the substrate layer and said grill section; molding the substrate layer, grill section, and the decorative layer into a formed automotive interior panel under pressure between two closed mold dies with the decorative layer spanning over the pins in the apertures in the substrate to form an integrated speaker grill with the panel; removing the molded formed panel and speaker grill after the thermoplastic material in the panel is cooled to allow the panel to be resolidified and the substrate and decorative layers to be bonded together. 
     In accordance with another aspect of the invention, a process for forming a combined speaker grill and automotive interior trim panel is characterized by the steps of: providing a substrate layer of a heated mat material having a content of thermoplastic material such that it is moldable under heated conditions; providing an aperture in the substrate layers; that is slightly smaller than the grill section placing a perforated grill section over the opening in the substrate with the respective edges overlapping, positioning a pin in each respective hole in the grill section with an end of the pin substantially coplanar with one side of the grill section; providing a decorative layer that is capable of being bonded to the substrate layer and grill section; molding the substrate layer grill section and the decorative layer into a formed automotive interior panel under pressure between two closed mold dies with the decorative layer spanning over the pins in the apertures in the substrate to form a integral speaker grill with the panel leaving an edge of the substrate layer uncovered; and punching out an additional grill section with a plurality of holes; removing the molded formed panel and speaker grill after the thermoplastic material in the panel is cooled to allow the panel to be resolidified and the substrate and decorative layers to be bonded together; and removing the punched out additional grill section for placement in an aperture of an another substrate layer. 
     In accordance with another aspect of the invention, a molded interior automotive panel and speaker grill combination includes a molded substrate layer having thermal plastic content and a flax fiber content. A plurality of apertures through the substrate are aligned with a speaker-mounted therebehind. A decorative layer is bonded on top of the substrate material and molded thereto. In one embodiment, the decorative layer is a porous carpet layer that spans over the plurality of apertures. In another embodiment, the decorative layer also has apertures therethrough that align with the apertures in the substrate. In another embodiment, a separate grill section is received over an opening through the substrate. Both the grill section and substrate are made from the same material. The grill is then bonded to the substrate about the aperture with the carpet layer spanning over both the grill and substrate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference is now made to the accompanying drawings in which: 
     FIG. 1 is a perspective view of a rear shelf trim panel according to one embodiment of the invention; 
     FIG. 2 is an enlarged segmented view of rear shelf trim panel shown in FIG. 1 with a speaker mounted thereunder; 
     FIG. 3 is a fragmentary sectional view through the lower and upper molds before molding of the rear trim panel shown in FIG. 2; 
     FIG. 4 is a view similar to FIG. 3 during a cutting and molding step; 
     FIG. 5 is a view similar to FIG. 4 after the upper mold is raised subsequent to the cutting and molding step; 
     FIG. 6 is a fragmentary, segmented and schematic view of a lower mold and punch press illustrating a method of manufacturing a modified embodiment according to the invention; 
     FIG. 7 is a view similar to FIG. 6 with the punch press punching apertures through the substrate layer; 
     FIG. 8 is a view similar to FIG. 7 showing the punch press lifted up after punching apertures in the substrate layer; 
     FIG. 9 illustrates the placing of a decorative layer and an upper mold die over the substrate layer and lower mold die; 
     FIG. 10 is a view similar to FIG. 9 with the lower and upper mold dies shown in the closed position; 
     FIG. 11 is a view similar to FIG. 10 with the mold dies opened and the formed rear shelf trim panel lifted off the lower mold die; 
     FIG. 12 is a perspective and exploded view of an alternate embodiment with the upper and lower mold pieces before assembly and molding; 
     FIG. 13 is a cross-sectional view of taken along the lines  13 — 13  shown in FIG. 12 with the upper and lower molds being closed; 
     FIG. 14 is a view similar to FIG. 12 after molding and opening of the molds; and 
     FIG. 15 is a cross-sectional view taken along lines  15 — 15  shown in FIG. 14 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, an automotive vehicle  10  has a rear shelf trim panel  12  mounted in the interior  11  of the vehicle and has speakers  14  concealably mounted thereunder. The rear shelf trim panel  12  as more clearly shown in FIG. 2 has a substrate layer  16  and a decorative carpet layer  18 . A plurality of apertures  20  and  22  extend through the substrate layer  16  and carpet layer  18  respectively. The apertures  20  through the substrate layer  16  are aligned with the apertures  22  through the carpet layer  18  to form passages that allow sound to transmit from the speaker  14  and into the automotive interior  11 . 
     The particular shape and contour of the rear shelf trim panel may vary depending on the model vehicle. It may also accommodate a rear brake light that is not shown for simplicity of the drawing. 
     The rear shelf trim panel has its substrate layer  16  made from a blend of flax and polypropylene unwoven mat. While the composition and ingredients of the mat may change it is desirable to have a blend of 50% polypropylene and 50% flax by weight. It is easily foreseen that the percentage of flax may vary between 40-70% be weight depending on the particular requirements and applications. The unwoven mat may have an uncompressed thickness of 11 mm. The mat may then be heated and compressed to 3 mm substrate layer  16  in order to provide the desired structural rigidity for most applications in a rear shelf trim panel environment. The mat may be heated to 200° C. to provide that the thermal plastic, polypropylene, is in a molten and moldable state. 
     The preheated substrate layer  16  is positioned in a mold assembly  24  that has a core side mold die  26  and a cavity or upper die  28  as shown in FIG.  3 . The core side  26  has a die insert  30  and the cavity side  28  has a punch insert  32 . The die insert  30  has a plurality of holes  34  that receive the punch dies  36  of insert  32 . A decorative layer such as a porous carpet layer  18  with a polypropylene back surface is placed over the substrate layer  16 . 
     The mold dies  26  and  28  are at ambient temperature and are heated only by the heated substrate layer  16  transfers to the mold dies. A cooling mechanism (not shown) may be provided to dissipate excess heat from the mold assembly  24 . 
     The mold dies  26  and  28  are closed as shown in FIG. 4 such that the punch dies  34  push into the holes  34  in die insert  32 . This causes punched scraps  38  of the carpet layer  18  and substrate layer  16  to be punched out and drop through the holes  34  in the die insert  30  to form apertures  20  and  22  simultaneously with the molding of the panel  12 . A pressure of five bars provides sufficient compressive force to achieve part configuration within the mold. 
     As shown in FIG. 5, after the rear shelf trim panel  12  is molded, the mold dies are opened and the panel  12  is removed. The scraps  38  are also removed by a mechanism (not shown) that strokes once per cycle to remove the scraps  38 . 
     Another embodiment can be made where the carpet layer  18  does not have apertures  22  therethrough. Alternatively, the carpet layer  18  spans over the apertures  20  in the substrate layer  16 . The process for making this embodiment is schematically illustrated in FIGS. 6-11. In this process, a set of retractable pins  40  are biased upward by a platform  42  set on springs  44 . The pins  40  extend through the apertures  34  in the die insert  30 . The substrate layer  16  is placed in the core side mold die  26  over the retractable pins as shown in FIG.  6 . As shown in FIG. 7, a die set punch section  46  has punch pins  48  that are aligned with pins  40  and punched to be received in holes  40 . As a result the pins  48  punch holes  20  through substrate layer  16 . As shown in FIG. 8, the punch set is lifted up and removed. The punched scraps  54  can be removed by lifting the pins  40  such they extend now through formed apertures  20  in layer  16 . Alternatively, the pins  48  of the punch set may have barbed lower ends which pull out the scrap pieces  54  and be removed from the pins  48  by a comb style sweeper. A further modification may be that pins  48  have optional stripper sleeves to remove the attached scrap members  54 . The important aspect is that the scraps  54  are removed so as not to interfere with the subsequent described steps. 
     As shown in FIG. 9, a decorative layer  18  such as the previously described carpet layer with a polypropylene back surface can then be placed over the substrate layer  16  and apertures  20 . Pins  40  are retained in a lifted position and remain in the apertures  20 . As shown in FIG. 10, an upper mold die  56  is then closed upon the lower mold die  26  and molds the carpet layer  18  and substrate layer  16  into shape and bonds the two together. After sufficient cooling, the upper mold die  56  is then lifted and the mold is open. The pins  40  are retracted from the apertures  20  and the formed panel  12  is then removed from core side mold die  26 . 
     In this fashion, the apertures  20  are concealed by the porous carpet layer  18  but function substantially the same as the apertures  20  in the first embodiment, namely by allowing excellent transmission of sound of all audible frequencies from a speaker  14  that is mounted under the substrate layer  12  and into an interior  11  of an automotive vehicle  10 . 
     In the alternate embodiment disclosed in FIGS. 12-15, each perforated grill section  60  is a separate member that is laid over as opening  62  in substrate layer  16 . The opening  62  is through a recessed peripheral edge  64  that is recessed a single thickness of the grill section  60 . 
     The grill section  60  contains the plurality of aperture  20  and is placed over aligned stationary pins  140  in lower mold are  126  after substrate layer  116  is positioned thereon with the mold having recess section  164  to accommodate recessed peripheral edge  64 . A hot melt or other adhesive is then applied to the top surface  66  of the grill section  60 . 
     A carpet layer  118  is placed over substrate  116  to cover over both grill sections  60  but leaving end section  168  exposed. The mold dies  128  and  126  are closed where grill sections  60  and carpet larger  118  are molded and bonded to the substrate layer  116  over openings  62  as shown in FIG.  15 . 
     Simultaneously as shown in FIG. 13, two additional grill sections  60  to be used in the future are formed with aperture  20  via the punch and die set  130  and  136 . Two end sections  168  of the substrate  16  are positioned over a die insert  130  in die  126 . The die insert  130  has a plurality of apertures  134  that receive punch die  136  in the upper mold die  128 . Scraps  138  drop through aperture  134 . The molds  126  and  128  have cutters to also cut the grill section  60  from the end section  168  of the substrate. The mold dies opened after sufficient cooling and the parts are demolded forming a complete panel  112 ; two additional grill sections  60  and two scrap ends  168 . 
     The cycle is then repeated with the additional grill sections  60  being used to form another panel  112 . 
     Other variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims.