Patent Publication Number: US-2013249258-A1

Title: Seat assembly having a heater wire and a method of manufacture

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d) to DE 10 2012 204 561.9, filed Mar. 22, 2012, the disclosure of which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present application relates to a seat assembly having a heater wire and a method of manufacture. 
     BACKGROUND 
     A heated seat is disclosed in U.S. Patent Publication No. 2011/0226751. 
     SUMMARY 
     In at least one embodiment, a method of manufacturing a seat assembly is provided. The method may include providing a substrate, positioning a heater wire on a surface of the substrate, and ultrasonically welding the heater wire to the substrate. 
     In at least one embodiment, a seat assembly is provided. The seat assembly may include a cushion, a trim cover assembly, and a heater wire. The trim cover assembly may be disposed on the cushion. The heater wire may be made of an electrically conductive material and may be disposed directly on the trim cover assembly and/or the cushion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an exemplary vehicle seat assembly. 
         FIG. 2  is a perspective view of an ultrasonic welding apparatus and a substrate having a heater wire that may be provided with the seat assembly. 
         FIGS. 3 through 12  are side section views of exemplary embodiments of a portion of a seat assembly having a heater wire. 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
     Referring to  FIG. 1 , an exemplary seat assembly  10  is shown. The seat assembly  10  may be configured for use in a vehicle, such as a motor vehicle like a car or truck. The seat assembly  10  may include a seat bottom  12  and a seat back  14  that may be pivotally disposed on the seat bottom  12 . The seat bottom  12  may be configured to be mounted to a surface  16 , such as a vehicle floor. 
     Referring to  FIGS. 1 and 2 , the seat bottom  12  and/or seat back  14  may include a substrate  20  that receives a heater wire  22  that may be used to heat a portion of the seat assembly  10  and a seat occupant. The substrate  20  may be a trim cover assembly  24  and/or a cushion  26  that may be provided with the seat bottom  12  and/or seat back  14 . The trim cover assembly  24  may provide at least a portion of an exterior seating surface of the seat assembly  10 . The trim cover assembly  26  may include one or more trim panels that may be made of any suitable material, such as fabric, leather, vinyl, or combinations thereof. The cushion  26  may be disposed under and may engage the trim cover assembly  24 . The cushion  26  may be made of any suitable material such as foam. 
     The heater wire  22  may be positioned on a surface of the substrate  20  with an ultrasonic welding apparatus  30 . In at least one embodiment, the ultrasonic welding apparatus  30  may include a table  32 , a heater wire source  34 , an ultrasonic welding head  36 , and at least one actuator  38 . 
     The table  32  may support the substrate  20  and may include a device like as a fixture or clamp for holding the substrate in a desired position. 
     The heater wire source  34  may be configured to provide the heater wire  22  to the ultrasonic welding head  36 . In at least one exemplary embodiment, the heater wire source  34  may be a reel or spool that is configured to rotate about an axis of rotation to feed the heater wire  22  to the ultrasonic welding head  36 . In at least one embodiment, the heater wire source  34  may be disposed proximate the ultrasonic welding head  36 . 
     The ultrasonic welding head  36  may be configured to ultrasonically weld the heater wire  22  to the substrate  20 . More specifically, the ultrasonic welding head  36  may provide or produce high-frequency ultrasonic acoustic vibrations that may produce localized heating for welding the heater wire  22  to the substrate  20 . As such, the heater wire  22  may be welded to the substrate  20  without providing an electrical current through the heater wire  22 . The heater wire  22  may be ultrasonically welded to the substrate  20  in a continuous or discontinuous manner. More specifically, the heater wire  22  may be continuously welded to the substrate  20  wherever the heater wire  22  engages the substrate  20  or may be discontinuously welded to the substrate  20  at discrete, spaced apart positions such that ultrasonic welds are absent in at least one position where the heater wire  22  engages the substrate  20 , such as between sequential ultrasonic welds. In addition, the ultrasonic welding head  36  may position and exert pressure on the heater wire  22 . This pressure may affect the location or penetration depth of the heater wire  22  with respect to substrate  20  and/or the ultrasonic weld location as will be discussed in more detail below. 
     One or more actuators  38  may be configured to move the table  32  and/or the ultrasonic welding head  36 . The actuator  38  may be of any suitable type, such as a mechanical, electromechanical, electrical, pneumatic, or hydraulic actuator. In at least one embodiment, one or more actuators  38  may be used to move the table  32  and/or the ultrasonic welding head  36  along one or more axes, such as orthogonal X-Y-Z axes. The actuators  38  may be controlled by a controller or may be part of a computer numerical control (CNC) system that may be used to move the table  32  and/or ultrasonically welding head  36  along a predetermined path to position the heater wire  22  on the substrate  20  in a predetermined pattern or configuration. For example, the actuator  38  and ultrasonic welding head  36  may cooperate to position the heater wire  22  on the substrate  20  in a serpentine or zigzag pattern in which the heater wire  22  extends back and forth across the surface of the substrate  20 . Opposing ends of the heater wire  22  may be positioned near each other to facilitate coupling to an electrical connector which may facilitate coupling to an electrical power source that may provide current that may be used to heat the heater wire  22 . 
     Referring to  FIGS. 2 and 3 , the heater wire  22  may be provided in various configurations. In at least one embodiment, the heater wire  22  may include a wire portion  40  and a coating  42 . 
     The wire portion  40  may be made of an electrically conductive material, such as a metal or metal alloy like stainless steel or a copper alloy. The wire portion  40  may have any suitable configuration, such as a flat or ribbon configuration that may have a generally rectangular cross section or a substantially circular cross section as shown in  FIG. 3 . In addition, the wire portion  40  may be disposed along or extend along a center axis  44 . 
     The coating  42 , if provided, may be disposed around and may engage an exterior surface of the wire portion  40 . The coating  42  may be made of a material that may be an electrical insulator and/or that may be ultrasonically welded to the substrate  20 . For example, the coating  42  may be a varnish, lacquer, or a polymeric material and may extend continuously around the wire portion  40  in one or more embodiments. If the coating  42  is omitted, then the wire portion  40  may engage and may be ultrasonically welded to the substrate  20 . 
     Referring to  FIGS. 3-12 , various section views that help illustrate a method of making a seat assembly  10  having a heater wire  22  disposed on a substrate  20  are shown. These figures show a heater wire  22  having a coating  42  and a wire portion  40  having a substantially circular cross section, but it is to be understood that heater wires having other cross sections or that do not have a coating  42  may be employed. In  FIGS. 4-7 , the substrate  20  upon which the heater wire  22  is provided is a cushion  26 . In  FIGS. 8-12 , the substrate  20  is a trim cover assembly  24 . 
     Referring to  FIGS. 3-6 , an exemplary sequence of method steps is shown. 
     First, the heater wire  22  may be positioned on a surface  50  of the cushion  26  as illustrated in  FIG. 3 . As such, the center axis  44  of the wire portion  40  may be disposed above the surface  50 . 
     Second, the heater wire  22  may be ultrasonically welded to the surface  50  as shown in  FIG. 4 . Ultrasonic welding may at least partially melt the coating  42 , thereby increasing the coating surface area that is in contact with the surface  50  and bonding the coating  42  to the surface  50 . In this embodiment, the heater wire  22  is ultrasonically welded such that the heater wire  22  is disposed on and does not substantially deform or penetrate the surface  50 . 
     Third, the trim cover assembly  24  may be installed over the cushion  26  and the heater wire  22  as shown in  FIG. 5 . Positioning of the trim cover assembly  24  may be preceded by positioning the cushion  26  on the seat bottom  12  or the seat back  14 . The trim cover assembly  24  may include a single layer that engages the cushion  26  and the heater wire  22  or multiple layers, such as a first layer  52  and a second layer  54 . The second layer  54 , which may be made of a compressible material such as felt or foam, may engage the cushion  26  and the heater wire  22  and may be compressed near the heater wire  22  to reduce deformation of the first layer  52 . 
     Referring to  FIGS. 6 and 7 , another embodiment of a seat assembly  10  having a heater wire  22  disposed on a cushion  26  is shown. In this embodiment, additional force is exerted upon the heater wire  22  during ultrasonic welding, which causes the heater wire  22  to penetrate the cushion  26  or deform the surface  50  such that the heater wire  22  is at least partially inserted into the cushion  26  as shown in  FIG. 6 . The additional force may result in the center axis  44  being aligned with or positioned below the surface  50  after ultrasonic welding, which may increase the surface area that engages or that is ultrasonic welded to the cushion  26  and may help reduce the distance by which the heater wire  22  extends from the surface  50 . The cushion  26  may be positioned or installed on the seat bottom  12  or the seat back  14  and the trim cover assembly  24  may then be installed over the cushion  26  and the heater wire  22  as shown in  FIG. 7 . Again the trim cover assembly  24  may include a single layer or multiple layers, such as a first layer  52  and a second layer  54 . The second layer  54  may engage the cushion  26  but may be compressed near the heater wire  22  by a lesser amount than the embodiment shown in  FIG. 5  due to positioning of the heater wire  22  within the cushion  26 . 
     Referring to  FIGS. 8-10 , another exemplary sequence of method steps is shown. First, the heater wire  22  may be positioned on a surface  60  of the trim cover assembly  24  as illustrated in  FIG. 8 . As such, the center axis  44  of the wire portion  40  may not penetrate the surface  60 . The trim cover assembly  24  may include a single layer or multiple layers as previously described. 
     Second, the heater wire  22  may be ultrasonically welded to the surface  60  as shown in  FIG. 9 . Ultrasonic welding may at least partially melt the coating  42 , thereby increasing the coating surface area that is in contact with the surface  60  and bonding the coating  42  to the surface  60 . In this embodiment, the heater wire  22  is ultrasonically welded such that the heater wire  22  is disposed on and does not substantially deform or penetrate the surface  60 . 
     Third, the trim cover assembly  24  may be installed over the cushion  26  as shown in  FIG. 10 . Positioning of the trim cover assembly  24  may be preceded by positioning the cushion  26  on the seat bottom  12  or the seat back  14 . Installation of the trim cover assembly  24  may cause the heater wire  22  to deform or penetrate the surface  50  of the cushion  26 . 
     Referring to  FIGS. 11 and 12 , another embodiment of a seat assembly  10  having a heater wire  22  disposed on a trim cover assembly  24  is shown. In this embodiment, additional force is exerted upon the heater wire  22  during ultrasonic welding, which causes the heater wire  22  to penetrate the trim cover assembly  24  or deform the surface  60  such that the heater wire  22  is at least partially inserted into the trim cover assembly  24  as shown in  FIG. 11 . The additional force may result in the center axis  44  being aligned with or positioned below the surface  60  after ultrasonic welding, which may increase the surface area that engages or that is ultrasonic welded to the trim cover assembly  24  and may help reduce the distance by which the heater wire  22  extends from the surface  60 . The cushion  26  may be positioned or installed on the seat bottom  12  or the seat back  14  and the trim cover assembly  24  may then be installed over the cushion  26  as shown in  FIG. 12 . 
     Ultrasonic welding of a heater wire  22  directly to a substrate  20  configured as a trim cover assembly  24  or cushion  26  may replace a laminated heater pad assembly that is provided as a separate component and installed between a cushion and a trim cover, thereby reducing manufacturing steps, material requirements, and associated costs. For instance, a laminated heater pad assembly that is manufactured a separate component may include a heating element that is sandwiched between layers of the heater pad assembly. Such a laminated heater pad assembly employs more layers, material, and manufacturing steps than the ultrasonically welded embodiments described herein. In addition, a laminated heater pad assembly must be installed in a seat assembly. As such, the laminated heater pad assembly may be mispositioned, folded, or damaged during assembly or may move after installation, thereby resulting in degraded or inadequate heating performance or may utilize additional fasteners, stitching, or adhesives to secure the laminated heater pad assembly. 
     While exemplary embodiments are described above, it is not intended that these embodiments 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. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.