Abstract:
The method of forming a cushion assembly ( 10 ) includes placing a pre-contoured trim layer ( 16 ) on a complimentary contoured mold ( 22 ), placing an air impervious adhesive film ( 18 ) thereover, drawing the trim layer ( 16 ) and film ( 18 ) against the mold ( 22 ), spraying a solvent activator ( 28 ) thereover, placing a contoured foam pad ( 14 ) over the adhesive film ( 18 ) and solvent activator ( 28 ), and compressing the foam pad ( 14 ) against the trim layer ( 16 ) by an upper platen ( 34 ) to bond the foam pad ( 14 ) and trim layer ( 16 ).

Description:
TECHNICAL FIELD 
     The subject invention relates to a method of securing a trim or fabric layer to a cellular foam pad, and more particularly of the type utilized for seating and back cushions in automotive seats. 
     BACKGROUND OF THE INVENTION 
     Various techniques have been developed for bonding a trim layer to a foam pad for use in seating, and particularly with automotive seat fabrication. One such type of process is disclosed in U.S. Pat. No. 4,692,199 issued Sep. 8, 1987 in the name of Kozlowski et al, and assigned to the assignee of the subject application. The patent discloses the method of applying a cloth fabric layer to a porous contoured mold, applying an adhesive film layer above the cloth layer, placing a foam pad upon the film, moving an upper platen against the foam pad to compress the foam pad against the adhesive-fabric layer, and applying steam through the porous mold to melt the adhesive and bond the foam and cloth together. 
     U.S. Pat. No. 4,929,304 issued May 29, 1990 in the name of Urai et al. discloses a method of bonding upholstery to a foam cushion including applying a layer of upholstery to a lower die, spraying a liquid adhesive on the foam cushion, and compressing the foam cushion against the layer of upholstery. 
     The problem with these prior methods is that, and especially when leather trim is utilized, direct application of heat may damage the leather trim layer. Furthermore, minimizing seat production time is also important in automotive seats. 
     SUMMARY OF THE INVENTION 
     The invention is directed toward a method of fabricating a cushion assembly. The method includes the steps of providing a trim layer and a foam pad, placing one of the trim layer or foam pad over a mold surface of a mold, placing an adhesive film over the trim layer or foam pad on the mold surface, applying a solvent activator to one of the trim layer or foam pad or adhesive film, placing the other of the trim layer or foam pad over the adhesive film on the mold, and compressing the adhesive film and solvent activator between the foam pad and trim layer to bond the foam pad and trim layer to one another by the adhesive. 
     The advantages of the invention include the ability of leather or other heat susceptible trim layers to be utilized in the bonding process. Furthermore, production time is decreased due to application of the solvent. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
     FIG. 1 is a perspective view of the preferred embodiment of an assembly utilized in fabricating the cushion assembly; 
     FIG. 2 is a schematic diagram showing the fabric layer and adhesive film disposed over the mold with an application of solvent activator; and 
     FIG. 3 is a schematic diagram of the foam pad and fabric layer compressed against one another for bonding by the adhesive film. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The method or process of fabricating a cushion assembly  10  generally utilizes the apparatus  12  as illustrated in FIG.  1 . The apparatus  12  is utilized to produce the cushion assembly  10  by bonding a cellular foam pad  14  to a trim layer  16  with an air impervious adhesive film  18  therebetween. The cushion assembly  10  is typically utilized as seat and back supports in seat assemblies for automotive vehicles. However, it is to be understood that the cushion assembly  10  may be utilized in other applications of a foam pad and cover material or trim. 
     The method includes providing the trim layer  16  and foam pad  14 . One of the trim layers  16  or foam pad  14  is placed over a mold surface  20  of a mold  22 . In the preferred embodiment, the trim layer  16  is placed directly over the mold surface  20 . Thereafter, an air impervious adhesive film  18  is placed over the trim layer  16  on the mold surface  20 . The mold  22  is preferably porous. A vacuum  24  is applied through apertures  26  in the mold  22 . The vacuum  24  draws the trim layer  16  and adhesive film  18  against the mold surface  20  in contour therewith. Wrinkles may be removed by stretching the trim layer  16  and film  18 . Thereafter, a solvent activator  28  is applied to either the trim layer  16  the adhesive film  18  or the foam pad  14 . Within one minute of applying the solvent activator, the foam pad  14  is placed against the adhesive film  18  and compressed against the mold  22  by an upper platen  34  to compress the foam pad  14  against the trim layer  16  to allow bonding together by the adhesive film  18 . One inch of compression is utilized in the preferred embodiment for two minutes. Thereafter, the compression may be removed and the cushion assembly  10  removed from the mold  22 . 
     In the preferred embodiment, the solvent activator  28  is sprayed directly onto the film  18  and is ketone based, such as available from Bostik, Inc. of Massachusetts. The adhesive film  18  is typically a polyamide with phenolic nitrile additive, also available from Bostik, Inc. The adhesive film  18  is thin, and feels like a single layer of trash bag. A preferred material which may be utilized as the adhesive film  18  is clear so the operator can see the fabric or trim layer  16  to remove wrinkles by pulling out the periphery. Once the solvent activator  28  is applied against the film  18 , the adhesive film  18  diffuses to bond the trim layer  16  and foam pad  14  and becomes air pervious. 
     The trim layer  16  may be upholstery, cloth or fabric, typically used to manufacture vehicle seats. Leather or vinyl trim layers are particularly suitable due to the non-application of direct heat. The trim layer  16  is fully sewn and/or contoured to the desired shape of the final seat. 
     The foam pad  14  may be the cellular type of various different known materials, such as the polyester type or polyurethane type. The foam pad  14  is also formed to the contour of the final cushion assembly  10  and mold  22 . 
     The process is implemented in the apparatus specifically disclosed in U.S. Pat. No. 4,692,199, incorporated by reference herein. As illustrated in FIG. 1, the apparatus  12  includes the mold  22  having a contoured mold surface  20 . The contoured mold surface  20  is of a shape complimenting the trim layer  16 . Passages or apertures  26  are provided in the mold  22  for establishing fluid communication with the upper mold surface  20 . A housing  30  is disposed below the upper mold surface  20  and mold  22  for providing an air tight chamber in communication with the apertures  26  in the mold  22 . The mold  22  is preferably made of aluminum. Any other suitable mold materials may be used, such as die cast, ceramic, etc. 
     The vacuum  24  is connected to the housing  30  to supply a vacuum pressure thereto and through the apertures  26  of the mold  22 . The vacuum  24  typically includes a vacuum pump and tank connected by fluid lines to the housing  30 , and controlled by a control circuit  32 , as described in the referenced patent. The heating which is set forth in the referenced patent is not utilized herein due to use of the solvent activator  28 . 
     Further included is the upper platen  34  which is utilized to compress the foam pad  14  against the trim layer  16  in the mold  22 . The upper platen  34  is suspended from a support structure  36  for vertical movement relative to the mold  22  for compressing the foam pad  14  against the molds  22 . A pneumatic cylinder moves the upper platen  34  as described in the referenced patent. 
     The Figures indicate that the adhesive bond is disposed over the entire surface of the foam pad  14  and trim layer  16 . However, in accordance with the subject application, the adhesive bond between the foam pad  14  and trim layer  16  may be only a portion of the mating surface, as commonly known in the art. 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.