Abstract:
A method for making a cover for a component of a vehicle passenger compartment comprising the steps of molding the cover for the component from a polymeric material, and forming an integrally-formed aesthetic feature in an uninterrupted portion of the cover which simulates a seam between regions of the cover.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/481,629, filed Nov. 12, 2003, and U.S. Provisional Application Ser. No. 60/481,603, filed Nov. 5, 2003, and is a continuation of U.S. application Ser. No. 10/711,979, filed Oct. 18, 2004. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to covers for trim components in a vehicle passenger compartment and more specifically to vehicular trim components with covers comprising composite stitching. 
     2. Description of the Related Art 
     Trim components, such as door armrests, center console armrests, and gear shifter boots, for a vehicle passenger compartment of luxury vehicles typically have a leather exterior surface, and leather is often an upgrade option for other vehicles. Leather is considered a highly desired and superior cover material because of its sleek appearance and distinguishable texture. The premium that consumers pay for leather surfaces arises not only from the higher material cost, but also from the manufacturing and assembly costs. 
     Usually, the leather cover on a trim component comprises two or more pieces of leather that are individually cut and sewn together with a manually operated sewing machine in several steps. To join two pieces of leather  100  and  102 , as illustrated in  FIG. 1 , the pieces  100  and  102  are layered with the exterior leather surfaces  104  facing each other, and a butt seam  106  is sewn along the pieces  100  and  102  at a predetermined distance, approximately one centimeter, from the edge. After the butt seam  106  is in place, the pieces  100  and  102  are folded away from each other such that the two exterior leather surfaces  104  form one continuous surface, which can be seen in  FIG. 2 , with a crease at the interface of the pieces  100  and  102 . The thread of the butt seam  104  is not visible from the exterior when the pieces  100  and  102  are folded open. To provide a refined appearance, the inside edges  108  and  110 , which are the portions of the pieces  100  and  102  that are approximately one centimeter wide, are folded away from each other and sewn to their respective pieces of leather  100  and  102 , as shown in  FIG. 3 . The resulting seams  112  and  114  are parallel to and spaced from the butt seam  106 . The three seams—the butt seam  106  and the two parallel seams  112  and  114  are known as a French seam  116  and are characteristic of leather covers for vehicular trim components. 
     After all the pieces of the leather are sewn together with French seams  116  to form a cover  118 , the cover  118  is assembled to a rigid shell  120  to construct the vehicular trim component  122 , as shown in  FIGS. 4A and 4B . The rigid shell  120  is commonly composed of a polymer material or composite material and provides structural support for and defines the shape of the trim component  122 . Cushioning, usually a foam layer (not shown) shaped to mate with the shell  120 , is positioned over the shell  120 , and the leather cover  118  is manually placed over the cushioning and hand-wrapped around the rigid shell  120 . The leather cover  118  is stapled to the shell  120 , by hand, around the entire edge of the cover  118 , as best seen in  FIG. 4B . Although the staples are not visible when the trim component  122  is installed in the vehicle compartment, the stapling process requires expensive manual labor and is very time consuming. Furthermore, leather covers  118  cannot be shaped to cover portions of the shell  120  having a small surface area or a complex shape, such as a pull cup  124  in door armrests. As a result, the leather surface trim component  122  is actually a composite component having leather and polymer surfaces. 
     In an effort to manufacture affordable trim components having the appearance of “cut and sew” hand-wrapped leather products, trim component manufacturers have turned to polymer molding processes. During such processes, molten polymer material, for example a polyvinyl chloride (PVC) or a thermoplastic elastomer (TPE), is injected into a mold, where it solidifies into a part having the shape of the mold. Molds for faux leather trim covers comprise a surface with a texture similar to leather and features resembling French stitching. While the surface texture and butt seams of molded products closely resemble the corresponding aspects of “cut and sew” hand-wrapped leather products, the molded seams parallel to the butt seam have an obvious faux appearance. The absence of thread in the parallel seams is an immediate indicator that the seam is a molded French seam and, therefore, the trim component does not have a leather surface. 
     SUMMARY OF THE INVENTION 
     In an embodiment of the invention, a method for making a cover for a component of a vehicle passenger compartment comprising the steps of molding the cover for the component from a polymeric material, and forming an integrally-formed aesthetic feature in an uninterrupted portion of the cover which simulates a seam between regions of the cover. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of two pieces of cut leather, each having an exterior leather surface, wherein the exterior leather surfaces are adjacent one another and a butt seam is sewn along the leather pieces at a predetermined distance from the edge; 
         FIG. 2  is a perspective view of the leather pieces from  FIG. 1 , wherein the pieces are folded away from each other to form a continuous surface with a crease at the butt seam; 
         FIG. 3  is a perspective view of the leather pieces from  FIG. 2  with the edges folded against their respective leather pieces and sewn to form a French seam; 
         FIG. 4A  is a front perspective view of a “cut and sew” hand wrapper leather vehicular trim component made with a leather cover comprising leather pieces similar to those shown in  FIG. 3 ; 
         FIG. 4B  is a rear perspective view of a “cut and sew” hand wrapper leather vehicular trim component from  FIG. 4A ; 
         FIG. 5  is a perspective view of a molded armrest cover; 
         FIG. 6  is perspective view of a molded armrest cover according to the invention and comprising a composite French seam with a molded butt seam and threaded side seams; 
         FIG. 7  is an enlarged view the region marked VII in  FIG. 6 ; 
         FIG. 8  is a sectional view of the molded armrest cover from  FIG. 6  taken along line  8 - 8 ; 
         FIG. 9A  is an exploded view of an armrest made with the molded armrest cover from  FIG. 6 ; 
         FIG. 9B  is a rear perspective view of the armrest from  FIG. 9A ; and 
         FIG. 10  is a perspective view of a molded center console cover with a composite French seam according to the invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The invention addresses the deficiencies of the prior art and provides a vehicular trim component with a molded cover having an appearance that closely resembles a “cut and sew” leather cover. The molded cover comprises a composite French seam that has a molded butt seam and threaded parallel side seams. 
     Referring now to the figures and to  FIG. 5  in particular, a molded armrest cover  10  comprises a top surface  12 , a pull cup  14 , and a side surface  16 . The top and side surfaces  12  and  16  are substantially orthogonal relative to each other, and the side surface  16  curves according to the contour of the top surface  12 . A bight  18  is located at the transition from the top surface  12  to the side surface  16 . The pull cup  14 , which is formed by a peripheral wall  20  and a bottom wall  22 , defines a recess  24  sized to receive a portion of a user&#39;s hand. A second bight  26  is disposed at the transition from the top surface  12  to the pull cup  14 . Each of the exterior surfaces  12 ,  14 , and  16  of the armrest cover  10  preferably have several small, molded-in, and somewhat randomly oriented lines or depressions to provide a surface texture similar to that of leather. The molded armrest cover  10  is preferably made of a polymer material, for example a polyvinyl chloride (PVC) or a thermoplastic elastomer (TPE), and manufactured with conventional polymer molding processes. 
     As illustrated in  FIG. 6 , the cover  10  can be adapted to have an appearance similar to an authentic “cut and sew” leather cover by incorporating one or more composite French seams  30  according to the invention. The composite French seams  30  are preferably located in areas, such as along the bight  18  between the top surface  12  and the side surface  16 , where real French seams are typically situated. 
     As best viewed in  FIGS. 7 and 8 , the composite French seam  30  comprises a center seam  32  between two parallel side seams  34  and  36 . The center seam  32  is incorporated into the polymer material during the molding process and is essentially a crease that simulates a butt seam. The side seams  34  and  36  are actual thread-stitched seams, and each side seam  34  and  36  is parallel to the center seam  32  and spaced therefrom by equal distances. The side seams  34  and  36  are sewn into the molded cover  10  with a manually or automatically operated sewing machine using the same thread that is employed in real French seams. Optionally, regions  38  and  40  between the center seam  32  and the side seams  34  and  36 , respectively, can be textured or raised to simulate a sight pucker, which is commonly generated when side seams of a French seam are sewn into a leather cover. To further provide a leather-like feel, a painted topcoat (not shown) comprising one or more layers can be optionally applied to the entire exterior surface of the cover  10 . 
     The combination of the molded center seam  32 , the thread-stitched side seams  34  and  36 , and the regions  38  and  40  therebetween, respectively, readily simulate a real French seam from an authentic “cut and sew” leather cover. In particular, utilizing thread for the side seams  38  and  40  adds an authentic feature to the composite French seam  30  and contributes to the overall “cut and sew” appearance of the cover  10 . 
     Referring now to  FIGS. 9A and 9B , the cover  10  with the composite French seam  30  provides an aesthetically appealing and robust exterior surface for a vehicular armrest  50 . In addition to the cover  10 , the armrest  50  comprises a rigid shell  52  and a cushion layer  54 . The shell  52 , which is well known to one skilled in the art, provides structural support for and defines the shape of the armrest  50  and is preferably composed of a polymer material or composite material. Generally, the shell  52  has a shape similar to the cover  10  and further comprises peripheral flanges  56  and  58  and a plurality of pins  60  for mounting the armrest  50  to a vehicle door. Optionally, the shell  52  has an aperture  62  and a vent  64 , whose purposes will become apparent hereinafter. The edges of the cover  10  wrap around the peripheral flanges  56  and  58 , and an adhesive or other suitable chemical bonding agent or mechanical fastener secures the cover  10  to the shell  52 . 
     The cushion layer  54  is disposed between the cover  10  and the shell  50  and has a varying thickness preferably not exceeding the heights of the flanges  56  and  58 . The cushion layer  54  is preferably a foam layer that is either foamed in place through the aperture  62  or cut, using a die, into a shape corresponding to that of the cover  10  and the shell  52 . If the cushion layer  54  is a foam-in-place layer, the foam material can optionally contain an adhesive to bond the cover  10  to the shell  32 . The foam provides a soft, cushioned ply beneath the cover  10  so that a vehicle occupant can comfortably rest a body part, such as an elbow, on the armrest  50 . Additionally, the combination of the cushion layer  54  and the cover  10  impart a tactile feel similar to that of a “cut and sew” hand-wrapped leather armrest. 
     The sequence of steps in the following descriptions of the manufacturing processes for the cover  10  and the armrest  50  is exemplary. The steps are presented in the following manner in order to provide a clear description of the manufacturing processes. In practice, the process steps can proceed in any logical and suitable order and are not limited to the order described herein. 
     The cover  10  with the composite French seam  30  according to the invention is manufactured in the following manner. Of course, it will be understood that the manufacturing steps described herein can be performed in any order which would be apparent to one skilled in the art. Liquid or partially liquid polymer material is introduced into a mold having a profile that is the inverse of the cover  10 . In addition to the general shape of the cover  10 , the mold accounts for the faux-leather surface texture, at least one center seam  32 , and the corresponding regions  38  and  40 . Once the polymer at least partially solidifies, the mold is opened, and the cover  10  is removed. If a top coat is desired, it can be painted onto the exterior surface of the cover  10 . 
     The threaded side seams  34  and  36  are stitched, with a manually or automatically operated sewing machine, into the cover  10  and adjacent to the at least one center seam  32 . Alternatively, the threaded side seams  34  and  36  can be simulated instead of being stitched, such as being formed as a series of in-molded indentations formed in generally parallel fashion adjacent to the center seam  32 . 
     After the stitching is completed and any applied coating and/or paint is sufficiently dry, the cover  10  is ready for use in the manufacture of the vehicular armrest  50 . 
     To assemble the armrest  50  with a foam-in-place cushion layer  54 , the cover  10  is attached to the shell  52  by placing the cover  10  onto the shell  52  and wrapping the edges of the cover  10  around the peripheral flanges  56  and  58 . The cover  10  and shell  52  are situated with a space therebetween for the cushion layer  54 . Next, the foam/adhesive is poured through the shell aperture  62  and into the space between the cover  10  and the shell  52 . Air within the space can escape through the vent  64 . As the foam solidifies, the cushion layer  54  forms and adheres to both the cover  10  and the shell  52 . 
     When the cushion layer  54  is a die cut foam layer, the armrest  50  is assembled in the following manner. At any time during the assembly process, adhesive is applied to any of the armrest components  10 ,  52 , or  54  to secure the cover  10 , the shell  52 , and the cushion layer  54  together. The cushion layer  54 , already cut into the proper shape, is positioned on the shell  52 , and then the cover  10  is placed over the cushion layer  54  and wrapped around the peripheral flanges  56  and  58  of the shell  52 . 
     Regardless of the type of cushion layer  54 , the processes to make and assemble the cover  10  and armrest  50  offer several advantages over the prior art “cut and sew” leather hand-wrapped processes. With particular reference to  FIGS. 4B and 9B , the cover  10  can be secured with adhesive; therefore, the armrest  50  does not require a plurality of staples, nor labor for inserting the staples, along the inside of the shell  52  to retain the cover  10  to the shell  52 . Another apparent advantage is that the composite French seam  30  can be fashioned faster and more efficiently than true French seams because the center seam  32  is molded rather than hand-sewn. Additionally, the cover  10  can be molded into any shape, which can include portions of the shell  52  having a small surface area or a complex shape, such as the pull cup  14 . As a result, these portions have a soft feel that is presently unattainable with leather covers. Furthermore, because the cover  10  and armrest  50  can be made and assembled with automated processes, the resulting product is dimensionally accurate and easily reproducible, thus resulting in a higher quality trim component that has an improved leather-like appearance and fit in the vehicle. 
     While the invention has been described thus far with respect to a cover  10  for an armrest  50 , the composite French stitching  30  can be utilized on a cover for any size, shape, or type of vehicular trim components. The invention is not limited to a cover for an armrest; the combination of the molded center seam  32  and the threaded side seams  34  and  36  can be incorporated into, for example, a cover  70  for a center console, which is illustrated in  FIG. 10 , a gear shift boot, a headrest, or any other interior vehicular trim component. 
     Molded covers according to the invention and vehicular trim components comprising such covers have an exterior surface that looks and feels like a true leather “cut and sew” surface. Molding the center, butt seam and thread-stitching the parallel side seams creates a composite French seam that has a more authentic appearance than completely molded French seams and is less costly than a true French seam. Furthermore, the polymer material of the molded cover is a proven production material and has less of a tendency to deteriorate over time than leather. Several other advantages of the molded covers for vehicular trim components are apparent from the foregoing description. 
     Of course, it will also be understood that, while the invention has been described herein with respect to a suitable improvement over a traditional leather trim component, the invention is also applicable as an improved replacement for traditional cut-and-sew vinyl, thermoplastic elastomer (TPE), thermoplastic urethane (TPU) components as well. 
     Further, while the invention has been described with respect to a French seam, other types of seams can be formed into the trim component. Thus, the particular type of seam (i.e., a French seam) described herein shall not be construed as limiting on the scope of the invention, but rather the formation of any type of seam known to one skilled in the art is contemplated as being within the scope of this invention. 
     It will be also understood that this invention also relates to decorative components where there is no foam layer between an outer skin/cover and a substrate therebeneath. For example, a door bolster (the decorative part of a door panel typically above the door armrest location) would be a suitable decorative member which typically does not include a foam layer. 
     While the preferred method of producing the flexible outer cover is the injection molding process there are a number of other processes that could be utilized. This would include but not be limited to rotocasting, slush molding, in mold spray urethane or any other process known to those skilled in the art. 
     This invention is also not limited to vehicular trim components. For example the seam formation articles, systems and methods described herein would be equally applicable to non-vehicular applications such as, for example, a seat back and/or arm rest in the furniture industry, such as in the office furniture industry. 
     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.