Abstract:
A method for forming a headliner assembly includes forming a main body blank having a periphery in a shape corresponding to a desired shape of the headliner assembly, the mold has a correspondingly shaped surface with a recess including an intermediate wall portion. The method includes introducing foam into the recess to simultaneously form at least one foam beam enclosing a selected component area, and join the at least one beam to the main body. The intermediate wall can be an accessory, and the beam may be formed to surround the component area. Additional foam application may be included to acoustically control the headliner&#39;s response to buzz, squeaks and rattles.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a method for forming headliners having shaped structural foam beams.  
           [0003]    2. Background Art  
           [0004]    The covering of the interior surface of a vehicle roof panel is known as a headliner, and may be made and installed in numerous ways. One prior method of making a headliner assembly placed energy absorbing foam pads in the headliner. The pad forming process included molding a block of foam, slicing the block into panels, die-cutting the panels, and compression molding the panels to form the pads. The pads are then attached to a preformed headliner body using assembly dies and an adhesive. Because of the multiple steps involved with forming the pads and attaching the pads to the headliner, this method is time consuming, labor intensive and costly, and also results in significant material waste.  
           [0005]    U.S. Pat. No. 5,845,458 discloses another method of making a headliner having deformable foam inserts disposed on side edges of the headliner. The method includes positioning a cover layer, a foam panel, and preformed foam inserts in a mold, and draping a flexible backing layer over the foam panel and foam inserts. Suitable adhesives are also positioned between the cover layer and the foam panel, and between the foam panel and the foam inserts. The mold is then closed to compression mold the foam panel and foam inserts, as well as to stiffen the backing layer. However, this method also involves multiple steps for forming the inserts and attaching the inserts to the remainder of the headliner, complicating and increasing the expense of headliner production.  
           [0006]    Another known process applies foam in place technology to provide energy absorbing pads at likely contact areas adjacent to impactable structures, such as roof panel edges. The known method for forming a headliner assembly includes simultaneously forming an energy absorbing member at the likely contact areas and joining the energy absorbing member to a main body of the headliner assembly proximate to the periphery of the body. While the method significantly reduces time and manufacturing costs compared with prior methods for locating and attaching energy absorbing foam pads proximate the periphery of headliners, the method complicates the headliner structure and the handling during production and installation because of the localized pads.  
           [0007]    Another known development forms structural beams of foam extending across a major dimension of the headliner. Although such beams can reinforce the headliner to reduce flexing during handling and reduce the difficulty of installing the headliner, the beams are not configured or located for support of accessories or components on the headliners, and are not aligned to address localized acoustic problems.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention overcomes the above disadvantages by providing a method for forming a headliner assembly or other internal finish panel having a foam in place structural member joined to a main body and shaped at a location or selected area identified for accessories or acoustic response. According to one embodiment of the invention, a method for forming a headliner assembly includes forming a main body in a shape corresponding to a desired shape of the headliner assembly; positioning the main body in a mold having at least one recess with an intermediate wall; closing the mold; and injecting foam into the recess to simultaneously form a beam shaped to border an accessory area within the support beam and joined to the main body. The beam may be across a major dimension of the main body, and as used in this application, the terms major dimension refer to an elongated but not necessarily linear distance extending along a length, a width or a diagonal of a vehicle roof area, and extending beyond a midpoint of at least one of the length and the width of the area and toward a point near, but not necessarily at, the ends of the vehicle roof section being covered by the headliner. When the selected area need not be open to receive accessories, the intermediate wall may be a component, such as a wiring harness, that becomes embedded in the beam.  
           [0009]    By using a mold having multiple recesses, a headliner assembly may be formed with multiple support beams. Similarly, if the recesses are joined in fluid communication, the beams may be joined to form a frame over a major area of the vehicle roof. A major area as used in this description refers to an expanse of surface area not necessarily rectangular extending beyond a midpoint of the roof area and along at least two of a length, a width, and a diagonal of the roof area toward, but not necessarily at, the ends of the vehicle roof section being covered by the headliner. According to another embodiment of the invention, foam may be injected simultaneously or sequentially into one or more recesses, and the foams may have different densities and/or chemistries. Alternatively, the mold in place operation may involve other processes for introducing foam into the recesses of a lower mold part. Regardless of how the foam is introduced to the recess or recesses in the mold parts, the beam protects or supports accessories at the headliner. Moreover, the foam may be shaped by recesses to form pads located as desired, for example, between beams or within framed areas, to affect acoustic energy such as buzzes, squeaks and rattles by means of the headliner.  
           [0010]    When the beam is shaped to surround a component area, the beam may provide important protection for the component or may support the component. Similarly, wiring may be embedded in a beam for mounting the wiring in position. In addition, headliner areas, for example, areas intermediate beams, or enclosed by a frame of beams may be provided with molded pads of acoustically damping foam or other foam chemistries that reduce buzzes, squeaks and rattles (BSR). 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The present invention will be better understood by reference to the following detailed description of a preferred embodiment when read in conjunction with the accompanying drawing, in which like reference characters refer to like parts throughout the views, and in which:  
         [0012]    [0012]FIG. 1 is a sectional, perspective view of a headliner assembly according to the present invention;  
         [0013]    [0013]FIG. 2 is an enlarged fragmentary sectional view of the headliner assembly of FIG. 1;  
         [0014]    [0014]FIG. 3 is a schematic view of a production-line arrangement for manufacturing the headliner assembly;  
         [0015]    [0015]FIG. 4 is a cross-sectional view of a blank used to manufacture the headliner assembly, wherein the blank is supported by a frame;  
         [0016]    [0016]FIG. 5 is a top view of a headliner assembly showing modified beam structure according to the present invention;  
         [0017]    [0017]FIG. 6 is a perspective view of the mold having recesses for forming the foam beams shown on the headliner of FIG. 5; and  
         [0018]    [0018]FIG. 7 is a sectional view taken substantially along the line  7 - 7  in FIG. 6. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    Referring first to FIGS. 1, 2 and  5 , a headliner assembly  10  according to the invention is adapted to be mounted to a roof  11  of a motor vehicle. The headliner assembly  10  includes a main body  12  that is reinforced by at least one and preferably, a plurality of structural foam beams. In the preferred embodiment, a forward beam  13 , a mid beam  14 , a rear beam  15  and longitudinal beams  17  and  19  are formed on and joined to the main body  12  near the periphery of the main body  12 . The main body  12  has a first or backing layer  16 , a second or substrate layer  18  and a cover layer  20 . The backing layer  16  is preferably a relatively stiff, semi-flexible scrim layer, and has a first or upper surface  22  that is positioned proximate the interior surface of the roof  11  of the vehicle, and a second or lower surface  24 . The substrate layer  18  is attached to the lower surface  20  of the backing layer  16 , such as with an adhesive. Nevertheless, changes in the structure forming the substrate  18  are also within the scope of the present invention.  
         [0020]    While the main body  12  and the substrate layer  18  may comprise any suitable material, in the preferred embodiment illustrated, the substrate layer  18  preferably comprises a thermoformable rigid urethane layer sandwiched between two fiberglass layers. The cover layer  20  may be any suitable cover material, such as cloth, vinyl or foam backed leather, and provided with or without a padding layer depending upon the use characteristics required. The cover layer  20  is attached to the substrate layer  18 , preferably with an adhesive. Alternatively, the headliner assembly  12  may be manufactured without a backing layer  16  and/or a cover layer  20  if not required for a particular application.  
         [0021]    The front beam  13 , mid beam  14 , rear beam  15  and side beams  17  and  19  may be disposed proximate or inwardly of peripheral portions of the roof  11  when the headliner assembly  10  is mounted to the roof  11 . For example, as shown in FIGS. 1, 2 and  5 , the beams  17  and  19  are disposed proximate side rails  26  of the roof  11  when the headliner assembly  10  is mounted to the roof  11 , such that the beams are positioned interiorly of the side rails  26 . The number of beams, and the size and shape of each beam may be varied depending on the application. Nevertheless, at least one of the beams, for example, mid beam  14 , includes a mid portion  84  that borders a selected component area.  
         [0022]    The beams  13 ,  14  and  15  are made of a foam that may be energy absorptive but other compositions are also within the scope of the present invention. While the foam may comprise any suitable material, in a preferred embodiment illustrated, the foam comprises a mixture of isocyanate and resin, which is polyurethane commercially available from several sources. Advantageously, the beams  13 ,  14 ,  15 ,  17  and  19  are molded directly onto the backing layer  16  such that the beams are simultaneously formed and joined to the backing layer  16  in a single operation, which is described below in greater detail. Alternatively, the beams may be molded directly onto the substrate layer  18  if the backing layer  16  is eliminated.  
         [0023]    In the preferred embodiment, the beams  13 ,  14 , and  15  are joined by forming in one piece with the side beams  17  and  19 . Such an arrangement forms a frame  25  of structural foam that rigidities the entire headliner assembly. Nevertheless, it is to be understood that beams according to the invention described in detail below can be formed individually without joining other beams, as desired, without departing from the scope and spirit of the present invention. In any event, at least one beam is formed to include a selected area surrounded by the foam forming the beam.  
         [0024]    [0024]FIG. 3 shows a production line arrangement  28  according to the invention for forming the headliner assembly  10 . The production-line arrangement  28  includes a component storage area  30 , a loading station  32 , a heating station  34 , a forming station  36 , a foam-in-place molding station  38 , a cutting station  40 , and a fixture installation station  42 . The production-line arrangement  28  further includes a conveyor system  43 , such as a chain conveyor, for transporting components between the loading station  32 , the heating station  34  and the forming station  36 .  
         [0025]    In the preferred production line arrangement  28 , the component storage area  30  preferably includes a source  44  of blanks  45 , wherein each blank  45  comprises a substrate layer  18  with a backing layer  16  attached thereto. The component storage area  30  further includes a plurality of sources  46 ,  48  and  50  of cover layers, wherein each cover layer source  46 ,  48  and  50  contains cover layers that are different in color and/or composition compared with another of the cover layer sources  46 ,  48  and  50 . At loading station  32 , a blank  45  and a particular cover layer  20  selected from one of the cover layer sources  46 ,  48  and  50  are positioned in a transport frame  51  (FIG. 4). The frame  51  is then mounted on the conveyor system  43 . An adhesive layer may also be positioned between the blank  45  and the cover layer  20  at station  32 .  
         [0026]    As shown in FIG. 4, the backing layer  16  of the blank  45  of the preferred embodiment preferably has an extended portion  53  that extends beyond the substrate layer  18  of the blank  45 . Preferably, the transport frame  51  grips the extended portion  53  to thereby support the blank  45  and the cover layer  20  on the conveyor system  43 . As another example, a conveyor system may be provided with upper and lower chains that grip the extended portion  53  therebetween. The substrate layer  18  of the blank  45  may be appropriately sized to closely match the final size or outline of the headliner assembly  10 , to thereby reduce scrap or waste material. Of course, other transports may be used without departing from the invention. The blank  45  and the cover layer  20  are then transferred by the conveyor system  43  to the heating station  34  shown in FIG. 4.  
         [0027]    The heating station  34  includes a platen assembly  54  having upper and lower heated platens that engage the blank  45  and the cover layer  20  to thereby heat the blank  45  and the cover layer  20 . Preferably, the platen assembly  54  also has a plurality of thermocouples for sensing temperature of the blank  45  and the cover layer  20 . Once sufficiently heated, the blank  45  and the cover layer  20  are transferred by the conveyor system  43  to the forming station  36 .  
         [0028]    The forming station  36  includes a first mold  56  having first and second mold portions for thermoforming the blank  45  and the cover layer  20  to form the main body  12 , such that the main body  12  has a shape that corresponds to a desired shape of the headliner assembly  10 . Preferably, both mold portions may also be chilled in any suitable manner, such as by circulating chilled fluid, such as water through the mold portions. The forming station  36  preferably includes multiple molds, similar to the first mold  56 , that can be alternately used to form different headliner shapes and sizes. The main body  12  is then transported manually or otherwise to the foam-in-place molding station  38 .  
         [0029]    The foam-in-place molding station  38  includes a second mold  58  for forming the foam beams on the main body  12 , to thereby form the headliner assembly  10 . The foam-in-place molding station  38  preferably includes multiple molds similar to the second mold  58  for forming various beam configurations on various headliner configurations as will be described below. As shown in FIG. 6, the mold  58  includes a first or upper mold portion  60 , and a second or lower mold portion  62 . The upper mold portion  60  has a mold surface  64  that corresponds with the formed shape of the cover layer  20 , or the formed shape of a surface of the main body  12  to which the cover layer  20  is attached. The lower mold portion  62  has a mold surface  66  that corresponds with the formed shape of the backing layer  16  of the main body  12 .  
         [0030]    The lower mold portion  62  includes a plurality of cavities or recesses  68 ,  70 ,  72 ,  73  and  75  for respectively forming the beams  13 ,  14 ,  15 ,  17  and  19 . Each of the recesses may be in fluid communication with one or more pour heads  74  that inject or otherwise introduce foam into the particular recess  68 ,  70 ,  72 ,  73  and  75 . For example, as shown in phantom line in FIG. 6, each of the recesses is in fluid communication with at least one pour head  74 , particularly if the recesses are separated from each other. Each of the recesses may also be in fluid communication with two or more pour heads  74 . In the embodiment shown, where all recesses are in fluid communication with each other, a single nozzle or pour head may introduce the foam into the recess. Nevertheless, multiple pour heads may be used to expedite the introduction of foam to the mold  58 . The pour heads  74  are connected to one or more sources of foam (not shown), such as a mixture of isocyanate and resin.  
         [0031]    At molding station  38 , the formed main body  12  is positioned between the mold portions  60  and  62 , and the mold portions  60  and  62  are closed together. Next, foam is injected by the pour heads  74  into the recesses  68 ,  70 ,  72 ,  73  and  75 . Because foam injected into the larger recesses  73  and  75  requires more time to expand and cure than foam injected into the smaller recesses  68 , foam may preferably be first injected into the recesses  73  and  75 , and subsequently into the recesses  68  when multiple nozzles are not available. As a result, expansion and curing of the foam may be arranged to conclude in all of the recesses at approximately the same time. The lower mold portion  62  may also be heated preferably in the range of 130° F. to 190° F. for isocyanate and resin to assist in the expansion and curing process of the foam, and to flash off water that may be associated with a mold-release agent applied to the mold parts such as sprayed on wax for an injection molding operation. The multiple pour heads feeding a particular one of the larger recesses may preferably inject foam simultaneously, or in closely spaced stages, so as to provide relatively consistent foam characteristics throughout.  
         [0032]    In any event, the mid beam  14  includes a mid bar  84  that includes diverging beam portions that form or surround a component area  86  within the headliner. This is formed by an intermediate wall that diverges the fluid foam to border a selected component area. As a result, the beam provides structural support for and around an accessory component such as a dome light which may be installed above the headliner. Such a beam protects the accessory or permits mounting to the headliner by the surrounds or partially enclosed walls, without requiring separate construction or assembly after formation of the headliner.  
         [0033]    Because the recesses  68 ,  70 ,  72 ,  73  and  75  or others may be separated from each other, the quantity or mass of foam per unit of recess volume delivered by the pour heads  74 , which is referred to as injection density of the pour heads  74 , can be varied from one to another of the recesses so as to vary the density of the resultant beams. For example, a larger quantity of foam per unit of recess volume can be delivered to narrower recesses  68 , such that the resultant beams have a greater density. Consequently, foam density can be increased in areas requiring greater strength, such as areas of the headliner assembly  10  that will be remote from a side rail or roof supporting A-pillar joints of a motor vehicle. Furthermore, foam densities can be decreased in areas requiring less strength so that overall material costs can be significantly reduced. Different foam compositions may also be used under the method according to the invention to form beams having different densities.  
         [0034]    The headliner assembly  10  may be precisely formed to achieve relatively close design tolerances with significantly fewer steps and assembly procedures. Because beams are not individually handled and stored, this method involves lower inventory, lower assembly costs and part handling costs compared with prior methods that separately form and install separate support structures and beams.  
         [0035]    Moreover, components such as wiring harnesses, preformed foam components such as head impact energy absorbing, for example, pads meeting code standards such as FMVSS  201 .a, foam cushions, or other accessories, may also form the intermediate wall. Components to be installed in the headliner may be positioned within the recesses in the cavity or shaped surface, of the female mold half as shown in FIG. 5, for embedding the component partially or completely in the beams formed in the mold. For example, as shown at  90 , a wiring harness may be positioned in a predetermined location with respect to functional components to be installed after construction of the headliner. For example, the wiring harness  90  as shown in FIG. 9, extends into the component area  86  so that any component installed above or carried by the headliner may be provided with electrical power through the harness  90 . Of course, the other end of the harness  90  is positioned for easy access to a power source or other coupling or connector in the electrical system, and may be made accessible to sources, coupling components or the like by cutting of the headliner assembly after the molding operation, for example, at cutting station  40  discussed below. Nevertheless, the method of constructing the foam beams also serves to embed and mount accessory components such as a wiring harness, energy absorbing member or other vehicle accessory components. Another example is shown at  100  where a plastic tube, for use as a rear window washer conduit, can be embedded in the foam. When the embedded component includes an end piece such as a coupler, the mold may include a dedicated recess that receives the coupling and protects it when the mold is closed.  
         [0036]    In addition, it may be appreciated that numerous portions of a motor vehicle interior can be subject to numerous audio disturbances such as buzzes, squeaks or rattles that result from operation of components within the headliner or other parts of the vehicle that are transmitted through the roof panel during operation of the vehicle and its drivetrain. Accordingly, a separate foam pad, such as overhead pad  96 , may be added on the back of the headliner assembly during the foam-in-place process to mute or dampen vibrations at areas subject to resonance or the transmission of audio disturbances. The pad  96  may be made of an acoustic foam that is absorbent of acoustic waves in the range of 0 hertz to 10,000 hertz. Accordingly, the mold may be modified to include additional channels  94 , in fluid communication with or independent of the beam forming recesses, that are filled during the molding operation at workstation  38 . These produce a foam pad mounted at selected locations to the headliner providing acoustic control or protecting against buzzes, squeaks and rattles as shown at  96  as predetermined to be desired. The pads may be secured to a main body  12  or other components of the headliner. Alternatively, the noise reduction pads may also be formed in recesses in fluid communication with channels for forming the foam beam so as to be made with the same pour heads used to inject foam into the beam forming channels. Preferably, as shown in the preferred embodiment of FIG. 7, the noise reduction pads are made from an acoustically absorbent foam, and may be smaller, thinner and thus less bulky than other portions of the structural beams, particularly when formed adjacent to, or within a peripheral frame formed by foam beams.  
         [0037]    When the headliner assembly  10  is transferred to the cutting station  40 , which is shown in FIG. 4, a computer controlled, water jet cutting device  80  trims the headliner assembly  10 . Trimming may include cutting openings through the headliner assembly  10 , for example, within the component area  86  or for communication or access to the couplers or terminals of the embedded wiring. The rigidity and dimensional stability is preferably closely matched to the final size or outline of the headliner assembly  10  so that the amount of trimming required is significantly reduced compared with prior methods of forming headliners. The headliner assembly  10  is then transferred to the fixture assembly station  42  where installation of such fixtures as coat hooks, dome lights, wire couplings and ornaments is completed. The headliner blank may also be trimmed before molding and foam introduction, particularly when couplings may be protected within the headliner during molding.  
         [0038]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.