Abstract:
A method of applying stitching to an outer skin layer of an interior component is provided herein. The method including the steps of: a) penetrating the outer skin layer at an entry point on a first surface of the outer skin layer with a curved needle; b) exiting the outer skin layer at an exit point on the first surface with the curved needle, wherein the steps of penetrating and exiting cause a first thread to pass through the entry point and the exit point on the outer skin layer; c) grabbing the first thread with a hook located proximate to the exit point; d) retracting the needle through the exit point and the entry point while pulling a second thread through the exit point via the first thread to form a stitch; e) advancing the outer skin layer to a new location with respect to the needle and hook; and f) repeating steps a-e until a predetermined amount of stitches are applied to the outer skin layer.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/040,979, filed on Aug. 22, 2014, the entire contents of which are incorporated herein by reference thereto. 
    
    
     BACKGROUND 
     This invention relates to an interior structure for a vehicle interior. More particularly, the invention relates to an apparatus and method for stitching vehicle interior components. Still further, various embodiments of the present invention relate to placing a decorative stitch on a trim piece regardless of whether it is used in a vehicle or not. 
     Currently, most stitching found in an automotive interior is of the functional variety, wherein two or more pieces of material (leather, vinyl, TPO, cloth, etc) are cut from a pattern and sewn together (cut-n-sew) prior to being wrapped around a component such as a seat cushion, head rest, arm rest, console lid, instrument panel substrate, etc. Such functional stitching is very labor intensive and is normally used only where required on low and mid-class vehicles. Functional stitching on decorate components such as instrument panel retainers and door panels has typically been restricted to higher class vehicles due to cost. 
     In recent years, automotive original equipment manufacturers (OEMs) have shown an interest in applying the “stitched” look to more vehicles over a wider range of price classes. A simulated non-functional stitch has been used in some applications; however, the ability to offer a simulated stitch in a contrasting color is not production feasible at this time. Additionally, more OEMs are requesting that a real or “live” stitch be used on decorate components to provide the look and feel of a true cut-n-sew component. 
     Current means of placing a decorative stitch on a 3D preformed automotive trim component consist of penetrating the part (skin, skin/foam, or skin/foam/substrate) with a needle from the top side of the part and engaging a hook or looper located on the backside of the part. These methods required access to both the front and backside of the part, which often limits the location of stitch placement on the parts. Placement of stitching on brows, sharp corners, and highly contoured surfaces as often seen with true cut and sew wrapped automotive interior trim is often very difficult. 
     Accordingly, it is desirable to provide a method and apparatus for producing a live, non-functional stitch on decorative automotive trim components. It is also desirable to provide a component with such a stitch. 
     SUMMARY OF THE INVENTION 
     A method of applying stitching to an outer skin layer of an interior component is provided herein. The method including the steps of: a) penetrating the outer skin layer at an entry point on a first surface of the outer skin layer with a curved needle; b) exiting the outer skin layer at an exit point on the first surface with the curved needle, wherein the steps of penetrating and exiting cause a first thread to pass through the entry point and the exit point on the outer skin layer; c) grabbing the first thread with a hook located proximate to the exit point; d) retracting the needle through the exit point and the entry point while pulling a second thread through the exit point via the first thread to form a stitch; e advancing the outer skin layer to a new location with respect to the needle and hook; and f) repeating steps a-e until a predetermined amount of stitches are applied to the outer skin layer. 
     Also provided herein is an interior component of a vehicle formed by the above method. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior trim piece may be a portion of an instrument panel of the vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior trim piece may be a portion of an instrument panel of the vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer, may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin; and wherein an intermediary layer is applied to a second surface of the outer skin layer, the second surface being opposite the first surface. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the intermediary layer may be a foam layer. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the substrate layer may be applied to the foam layer and the substrate layer may be formed from plastic. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, further embodiments may include an interior component formed by the method of claim  1 . 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior trim piece may be a portion of an instrument panel of the vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin; and wherein an intermediary layer may be applied to a second surface of the outer skin layer, the second surface being opposite the first surface. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the intermediary layer may be a foam layer and wherein a substrate layer may be applied to the foam layer and wherein the substrate layer may be formed from plastic. 
     In another embodiment, a method of applying stitching to an interior component, having an outer skin layer, a substrate layer and an intermediary layer located between the outer skin layer and the substrate layer is provided. The method including the steps of: a) penetrating the outer skin layer at an entry point on a first surface of the outer skin layer with a curved needle; b) exiting the outer skin layer at an exit point on the first surface with the curved needle, wherein the steps of penetrating and exiting cause a first thread to pass through the entry point and the exit point on the outer skin layer; c) grabbing the first thread with a hook located proximate to the exit point; d) retracting the needle through the exit point and the entry point while pulling a second thread through the exit point via the first thread to form a stitch; e) advancing the outer skin layer to a new location with respect to the needle and hook; and f) repeating steps a-e until a predetermined amount of stitches are applied to the outer skin layer. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin; and the intermediary layer is a foam layer and the substrate layer is formed from plastic and wherein during the penetrating step the needle also passes through the intermediary layer. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior trim piece may be a portion of an instrument panel of the vehicle. 
     In yet another embodiment, a method of applying stitching to an interior component having an outer skin layer and a foam layer applied thereto is provided. The method including the steps of: a) penetrating the outer skin layer at an entry point on a first surface of the outer skin layer with a curved needle; b) exiting the outer skin layer at an exit point on the first surface with the curved needle, wherein the steps of penetrating and exiting cause a first thread to pass through the entry point and the exit point on the outer skin layer and wherein the foam layer is applied to a second surface of the outer skin layer, the second surface being opposite the first surface and wherein the needle also passes through a portion of the foam layer as it travels through the entry point and the exit point; c) grabbing the first thread with a hook located proximate to the exit point; d) retracting the needle through the exit point and the entry point while pulling a second thread through the exit point via the first thread to form a stitch; e) advancing the outer skin layer to a new location with respect to the needle and hook; and f) repeating steps a-e until a predetermined amount of stitches are applied to the outer skin layer. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the intermediary layer may be a spacer fabric. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior trim piece may be a portion of an instrument panel of the vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the interior component may be an interior trim piece of a vehicle. 
     In addition to one or more of the features described above, or as an alternative to any of the foregoing embodiments, the outer skin layer may be formed from the group consisting of vinyl, leather and thermoplastic polyolefin; and the intermediary layer may be applied to a second surface of the outer skin layer, the second surface being opposite the first surface and wherein the intermediary layer is a foam layer and a substrate layer is applied to the foam layer, wherein the substrate layer is formed from plastic and wherein the curved need passes through the outer layer, the foam layer and the substrate layer when the stitch is formed. 
     In yet another embodiment, a method of applying stitching to an outer skin layer of a component is provided herein. The method including the steps of: a) penetrating the outer skin layer at an entry point on a first surface of the outer skin layer with a curved needle; b) exiting the outer skin layer at an exit point on the first surface with the curved needle, wherein the steps of penetrating and exiting cause a first thread to pass through the entry point and the exit point on the outer skin layer; c) grabbing the first thread with a hook located proximate to the exit point; d) retracting the needle through the exit point and the entry point while pulling a second thread through the exit point via the first thread to form a stitch e advancing the outer skin layer to a new location with respect to the needle and hook; and f) repeating steps a-e until a predetermined amount of stitches are applied to the outer skin layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details appear, by way of example only, in the following description of embodiments, the description referring to the drawings in which: 
         FIG. 1  is a cross-sectional of a standard double stitch being formed in accordance with an exemplary embodiment of the present invention; 
         FIG. 2  is a cross-sectional of a simulated welt double stitch being formed in accordance with an exemplary embodiment of the present invention; 
         FIG. 3  is a cross-sectional of a double stitch being formed in a corner in accordance with an exemplary embodiment of the present invention; 
         FIG. 4  is a cross-sectional of a double stitch being formed in brow tip in accordance with an exemplary embodiment of the present invention; 
         FIG. 5  is a cross-sectional of a double stitch being formed in a deck seam in accordance with an exemplary embodiment of the present invention; 
         FIG. 6  is a view of a double stitch (French seam) formed in accordance with an exemplary embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of a double stitch (French seam) formed in accordance with an exemplary embodiment of the present invention; 
         FIGS. 8A and 8B  illustrate at least two hook to needle orientations; and 
         FIGS. 9-19  illustrate a stitch cycle according to one non-limiting embodiment. 
     
    
    
     Although the drawings represent varied embodiments and features of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to illustrate and explain exemplary embodiments the present invention. The exemplification set forth herein illustrates several aspects of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     Turning now to the drawings, wherein to the extent possible like reference numerals are utilized to designate like components throughout the various views, in  FIG. 1  it is seen that an interior portion  10  of a vehicle is illustrated. In one implementation the interior portion  10  may be any portion of an interior of the vehicle. For example, portion  10  may comprise a portion of an instrument panel of a vehicle. Of course, the portion  10  may be located on any surface within the vehicle. Still further, the methodology disclosed herein may be applied to items or components used in other non-vehicular manufacturing processes and thus portion  10  may refer to any article of manufacture. 
     The portion, interior portion, component, item or part  10  may be a single layer or multi-layered construction. In one embodiment, the interior portion, portion or component  10  includes at least an outer skin layer  12  having a substantially smooth outer surface and an underside facing away from the outer surface. The outer skin layer  12  is preferably formed of a plastic material of substantial flexibility and aesthetically pleasing character. Of course, other materials natural (e.g., leather, etc.) and simulated coverings are contemplated to be used in various embodiments of the present invention. In one embodiment, the interior portion is a decorative element of a vehicle interior. 
     In order to enhance the softness of interior portion and in one embodiment, a layer of cushioning support material  14  may be provided in the region below the outer skin layer  12 . It is contemplated that the cushioning support material may be of any number of different constructions although a foamed material such as cross linked polypropylene (XLPP) or polyurethane (PU) foam may be potentially preferred. A substrate panel  16  of dimensionally stable plastic or other suitable material may also be disposed below the cushioning support material. 
     According to one embodiment, the cushioning support material and the substrate panel may serve cooperatively to provide a support structure for the outer skin layer  12 . 
     It is contemplated that PU foam forming the cushioning support material may be blown between the outer skin layer and the substrate panel so as to form a multi-layered composite structure. It is also contemplated that the cushioning material may be attached to the outer skin layer in a preliminary cladding operation so as to form a preliminary layered composite which may thereafter be applied across any substrate panel as may be utilized. It is also contemplated that the cushioning material may be attached to the outer substrate layer in a preliminary cladding operation so as to form a preliminary layered composite which may thereafter be wrapped with an outer skin layer. 
     Still further, the interior piece or decorative element  10  may be anyone of a single layer (skin  12  only), a double layer (skin  12 /foam  14 ) or a triple layer (skin  12 /foam  14 /substrate  16 ). In yet another alternative embodiment, the intermediary foam layer  14  between the skin  12  and substrate  16  may be a spacer fabric  14 ′ instead of a foam layer. In yet another alternative embodiment, the spacer fabric  14 ′ may be used in conjunction with the foam layer  14  either between skin  12  and foam layer  14  or between substrate  16  and foam layer  14  or between both the skin  12  and foam layer  14  and foam layer  14  and substrate  16 . See for example, the dashed lines in  FIG. 7 . Accordingly, the methods and related apparatus disclosed herein are contemplated as being used with anyone of the aforementioned interior piece  10  configurations. 
     As discussed above, there is a desire to provide a live, non-functional stitch  18  on decorative automotive trim components without using costly cut-n-sew technologies. In accordance with one embodiment of the present invention, the method is used to apply a double stitch  18  wherein stitches are located adjacent (e.g., opposite and parallel to each other). 
     Various embodiments of the present invention are directed to an alternative method of applying decorative stitching to unformed and preformed material constructions used in the transportation industry or vehicle and vehicle part manufacture. The methods disclosed herein can be used for both flatstock material (cut-n-sew) but provides greater benefit when used on a part that has some degree of rigidity such that it cannot be easily flattened without causing damage to the material. The stitch is applied to the component from one side (the decorative side) of the part only, such that no access to the backside of the part is required. The stitch is formed using a curved needle  20  which passes into the decorative side of the part at an entry point and then protrudes from the same decorative side at an exit point opposite to the location of the corresponding entry point but on the same decorative side of the part. At this point a hook  22  of a rotating or rotatable bobbin assembly  30  engages the needle thread  24  or a loop of the needle thread  24  just after the start of the needle  20  retraction back through the same point of protrusion or exit point. During needle retraction and upon release from hook  22 , the needle thread  24  or loop of needle thread  24  engages or is wrapped around a bobbin thread  42  and pulls the bobbin thread  42  from the bobbin assembly  30  through the exit point of the needle to form a stitch. 
     As discussed further below, the engagement of the needle thread  24  and the bobbin thread results in the formation of a knot  44 , which is located between the entry point and the exit point and is below the surface of outer skin layer  12 . 
     Once the needle  20  retracts completely through the point of entry the article  10  is then advanced/moved to repeat the process. In other words, the part  10  is then moved slightly and the needle  20  passes into the decorative side of the part at another entry point adjacent to the last entry point and then protrudes from the same decorative side at another exit point adjacent to the last exit point and opposite to the location of the corresponding entry point but on the same decorative side of the part. Again, the hook  22  engages the needle thread  24  just after the start of the needle  20  retraction back through the same point of protrusion or exit point. During needle retraction, the needle thread  24  engages and pulls the bobbin thread  42  through the exit point of the needle to form a stitch. Once the needle  20  retracts completely through the point of entry the article  10  is then advanced or moved by a mechanism  26  to repeat the process. (Alternatively, the article  10  is manually moved by the individual who is performing the sewing process prior to the process being repeated (e.g., application of the next stitch). 
     As these steps are repeated a double stitch (e.g., two sets of stitches parallel to each other one running along the need entry points and one running along the needle exit points) is provided in the part or article  10 . 
     In an alternative embodiment, the part  10  is stationary and the needle  20  and hook  22  move with respect to the part  10  by for example a mechanism or robot  28  operably coupled to the needle  20  and hook  22 . 
     Depending on the material construction, the needle  20  can penetrate the decorative layer  12 , foam  14  (if required) and substrate layers  16  (if required), or decorative layer  12  and foam  14  (if required) only or in applications where only the decorative outer layer  12  is used the needle can penetrate the outer layer only  12  and depending on the thickness of the outer layer  12  the needle  20  does not necessarily need to pass completely though this layer as long as it enters from the decorative side and exits through the same decorative side at a different location. In the embodiment of only a single layer  12 , the knot  44  may be located in the outer layer  12 . In the embodiment of a component with only a decorative layer  12  and the foam layer  14 , the knot  44  may be located in the foam layer  14 . In the embodiment of a component with a decorative layer  12 , foam layer  14  and substrate layer  16 , the knot  44  may be located in the substrate layer  16  or alternatively in the foam layer  14 . Of course and in accordance with various embodiments of the present invention, the knot  44  may be located in or below any of the layers as long as it is below an outer show surface or the first surface of layer  12  that is penetrated by the needle  20 . 
     The portion or product  10  can be sewn either manually or automatically, although as part size increases the use of robotic sewing becomes more plausible due to handling concerns. 
       FIGS. 8A and 8B  illustrate two possible orientations of the hook  22  with respect to needle  20 . In  FIG. 8A , a vertical hook  22  is parallel to the needle  20  sewing direction. In  FIG. 8B , the vertical hook  22  is perpendicular to the needle  20  sewing direction. Although only two orientations are illustrated it is understood that numerous orientations may be within the scope of various embodiments of the present inventions. As illustrated in  FIGS. 8A and 8B , the hook  22  is located on a bobbin assembly or bobbin case  30 , which rotates in the direction of arrow  32  about axis  34 . As hook  22  rotates the needle thread  24  or loop of needle thread  24  is grasped by the hook  22  proximate to the scarf  36  of the needle  20 . 
     Referring now to  FIGS. 9-19  various steps of a stitch cycle or cycles according to one non-limiting embodiment are illustrated. In  FIG. 9  the hook  22  engages the needle thread  24  as the needle  20  begins retraction in the direction of arrow  38  from bottom dead center (BDC) of needle  20 . Thereafter and as illustrated in  FIG. 10 , the hook  22  pulls the needle thread  24  around a bobbin  40  of bobbin assembly  30  as needle  20  continues to retract in the direction of arrow  38  and the bobbin  40  and hook  22  of the bobbin assembly  30  rotate in the direction of arrow  32 . 
       FIG. 11  illustrates the hook  22  pulling the needle thread  24  as the needle  20  continues to retract in the direction of arrow  38 .  FIG. 12  illustrates the hook  22  beginning to release the needle thread  24  as the bobbin assembly  30  rotates in the direction of arrow  32 . 
     In  FIG. 13 , the released needle thread  24  pulls a bobbin thread  42  tight against the part  10  forming a new stitch  18  as the part  10  is advanced forward relative to the needle  20 . In  FIG. 14 , the stitch  18  is complete and the part  10  is located at a new position for the start of a new stitch  18 . Also shown in  FIG. 14  is that a thread knot  44  is located in the foam layer  14  or below outer layer  12 . Accordingly, a knot  44  is formed every time the hook  22  carries the needle thread  24  around the bobbin case or bobbin assembly  30 . Once the hook  22  releases the needle thread  24 , it pulls a length of bobbin thread  42  coming out from the center of the bobbin case or bobbin assembly  30  (from a bobbin winding, which is housed within the bobbin case  30 ). As the part  10  is then translated relative to the needle  20  and hook  22 , the hook  22  picks up the next needle thread  24  and wraps it around the bobbin case and thread  42  once again. The cycle repeats itself, as both needle and bobbin thread  24 ,  42  are continuous. 
       FIG. 15  illustrates the part  10  in a new location as it is ready for the start of the next stitch. In  FIG. 16 , the next stitch cycle is initiated and the needle  20  begins to move in the direction of arrow  46  and the part  10  is once again penetrated by needle  20 .  FIG. 17  shows the needle  20  once again exiting the part  10  and in  FIG. 18  the hook  22  engages the needle  20  to pick up the needle thread  24 .  FIG. 19  shows the hook  22  pulling the needle thread  24  around the bobbin  40  as the needle  20  is retracted in the direction of arrow  38  and the stitch cycle continues until the desired amount of stitches  18  are applied to the part  10 . 
     Some notable advantages of this method are that it: permits the stitching of a semi-finished or finished soft clad substrate skin  12  or skin  12  and foam  14  without penetrating the rigid substrate material  16  itself, resulting in no loss of component integrity at the stitch line; permits the sewing of a foamed-in-place product after foaming; allows for the use of a single needle  20  that produces a double thread (French seam) stitch pattern and/or other decorative patterns (See the attached FIGS.); allows for improved part fixturing for automated (robot) sewing as no backside part access is required; allows for the thread knot to be now confined within a much thicker cross section thereby reducing the chance of appearance on the top side of the part (e.g. causing “snake eye” effect for example, see the location of threaded knot  44  in the foam layer as illustrated in at least  FIG. 14 ); allows for access to application areas (previously inaccessible) that can now be sewn with stitches for example, cluster brow tips, sharp radii along the edges of the part, and other extremely narrow channels; and allows for the opportunity to produce alternative decorative styles such as welt beads (See at least  FIGS. 1-7  attached hereto) without additional materials or labor. 
     As used herein, the terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. In addition, it is noted that the terms “bottom” and “top” are used herein, unless otherwise noted, merely for convenience of description, and are not limited to any one position or spatial orientation. 
     The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (e.g., includes the degree of error associated with measurement of the particular quantity). 
     While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the present application.