Abstract:
A method of manufacturing a seat that includes the steps of attaching adjacent upholstery panels with a locator strip and attachment strip sandwiched therebetween. The attachment strip includes an enlarged edge portion that engages clips in a molded foam seat backing. At least a portion of the locator strip is torn away along a line of perforations formed therein.

Description:
TECHNICAL FIELD 
     The present invention relates generally to processes and designs for attaching upholstery material to a seat backing, and relates more particularly to such a design and process wherein a locator strip and an attachment strip are secured to adjacent pieces of upholstery material and the attachment strip is engaged with clip retainers in the seat, allowing part of the locator strip to be torn away. 
     BACKGROUND OF THE INVENTION 
     Conventional vehicle seats generally include one or more backing members, and a plurality of upholstery panels positioned thereon. Various processes and designs have been developed over the years for attaching the upholstery material onto the backing. Automated methods are known whereby the upholstery material is positioned by a machine onto the pre-formed backing material, as well as methods wherein an operator attaches the upholstery material manually. 
     In one common manual technique, an operator positions the upholstery material and secures the same to the backing material by sliding a retaining member attached to adjacent pieces of upholstery material into a receiving groove in a foam cushion or backer. This process allows the upholstery to be attached to the backer relatively quickly and easily, however it is necessary to fold one of the adjacent upholstery panels double, i.e. backwardly against the opposing piece of upholstery material so that the operator can visually determine the appropriate orientation and positioning of the retaining member for receipt in the groove. 
     In another known design, a robotic machine is utilized to position upholstery material proximate a mold in which a formable foaming material is injected, which solidifies to create the backer for the seat. The solidification of the foam material adheres to a retaining member extending between the adjacent upholstery panels. In this design, the robotic device grasps a strip that is inserted and attached between the adjacent panels, which may be tom away along a perforated line after the molding process is complete. 
     SUMMARY OF THE INVENTION 
     The present invention provides a design and process for attaching upholstery material to a seat cushion or backing. The design preferably includes a locator strip and an attachment strip secured between adjacent upholstery panels attached with longitudinal stitching lines. The locator strip and attachment strip may be one integral piece, or they may be formed as separate pieces. A first stitching line preferably penetrates both pieces of cover material as well as the locator strip and attachment strip. A second stitching line is substantially parallel to the first stitching line and preferably pierces both of the cover panels and the locator strip, but does not pierce the attachment strip. The second stitching line is preferably positioned inboard of the attachment strip. During seat assembly, the locator strip can be manually grasped from an exterior side of the upholstery covering, and the material manipulated such that the attachment strip may be pushed into a complementary groove in the seat backer. One or more clips molded into or otherwise attached to the backer preferably snap-fit with the attachment strip. Once positioned appropriately, the locator strip may be tom away from the seat assembly along longitudinal perforations formed in the strip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectioned end view, partially in perspective of a cover attachment assembly according to a preferred embodiment of the present invention; 
         FIG. 2  is a sectioned end view, also partially in perspective of the cover assembly of  FIG. 1 , illustrating a locator strip in a partially torn position; 
         FIG. 3  is a sectioned side view along line A—A of  FIG. 2 ; 
         FIG. 4  is a sectioned end view partially in perspective of a second preferred embodiment of the present invention; 
         FIG. 5  is a partial enlarged view of the cover attachment assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , there is shown a seat cover assembly  10  according to the present invention, adapted for attaching to a seat backing  12 . Seat cover assembly  10  includes first and second upholstery panels  11 A and  11 B. Upholstery panels  11 A and  11 B are joined at a seam  15  and preferably stitched together there along via first and second stitching lines  20  and  30 . A locator strip  40  and attachment strip  50  are preferably sandwiched between upholstery panels  11 A and  11 B and extend substantially along a length of seam  15 . Locator strip  40  and attachment strip  50  may be formed integrally, e.g. as a single plastic extrusion, or they may be formed as individual pieces. In a preferred embodiment, locator strip  40  and attachment strip  50  are positioned adjacently; however, attachment strip  50  might be positioned on the opposite side of one of upholstery panels  11 A and  11 B from locator strip  40 . Locator strip  40  is preferably an elongate rectangular plastic piece having a substantially uniform thickness. In a preferred embodiment first stitching line  20  pierces both of upholstery panels  11 A and  11 B as well as locator strip  40  and attachment strip  50 . While  FIG. 1  illustrates locator strip  40  and attachment strip  50  substantially as a uniform piece, in alternative preferred embodiments locator strip  40  and attachment strip  50  include a region  60  that overlaps proximate first stitching line  20 , as shown in  FIG. 5 . Thus, when seat cover assembly  10  is assembled, a portion of attachment strip  50  is positioned in an overlying relationship with a portion of locator strip  40 , and first stitching line  20  is subsequently formed therethrough. Second stitching line  30  preferably pierces both of upholstery panels  11 A and  11 B as well as attachment strip  50 , however, locator strip  40  preferably does not extend sufficiently far in an outboard direction between panels  11 A and  11 B such that it is pierced by second stitching line  30 . As used herein, the term “outboard” should be understood to refer to a direction toward the edges of panels  11 A and  11 B that comprise seam  15 , whereas “inboard” should be understood to refer to an opposite direction, i.e. away from seam  15 . 
     Seat backing  12  is preferably a solid piece of pre-formed foam material well known in the art. The present invention is contemplated for use with pre-formed seat backings, as opposed to systems wherein a seat backing if formed during cover assembly, such as by foaming the backing material while the cover is positioned thereover. A groove  14  is formed in seat backing  12 , preferably during the molding process. A longitudinal slit  16  may be formed in groove  14 , as described below. In a preferred embodiment, an assembly worker can grasp locator strip  40  and manipulate seat cover assembly  10  such that the attached portions of upholstery panels  11 A and  11 B, along with attachment strip  50  can be inserted into groove  14 . This step may be performed “blind,” that is by grasping locator strip  40  from an exterior cover side of the upholstery panels  11 A and  11 B, and moving attachment strip  50  to an appropriate position, aligned with groove  14 , then pushing attachment strip  50  into place. This step can be carried out without the need for flipping the upholstery panels such that they are doubled over to visually identify the appropriate place for attachment strip  50 . 
     Turning to  FIG. 2 , there is shown seat cover assembly  10  engaged with seat backing  12 . Upon engaging cover  10  and backing  12 , locator strip  40  may be torn away from seam  15  along the perforations formed by first stitching line  20 , rendering an aesthetically pleasing appearance to the covered seat. Embodiments are contemplated wherein the entire strip  40  is pulled free from seam  15 , as well as embodiments wherein a portion of strip  40  remains. A plurality of perforations  41  are illustrated in  FIG. 2  and represent points at which locator strip  40  is longitudinally pierced by the stitches that form first stitching line  20 . It should be appreciated, however, that perforations  41  need not be formed by the stitches, but could instead be formed by some other means. Attachment strip  50  preferably includes an arrow-shaped, barbed or otherwise enlarged longitudinal edge portion  51  for engagement with complementary clips in backing  12 , described below. Various adhesives, epoxies, etc. may be utilized to enhance the retention of attachment strip  50  and the edges of upholstery panels  11 A and  11 B in groove  14 . 
     Turning now to  FIG. 3 , there is shown a sectioned view of the various components of seat cover assembly  10  taken along line A—A of  FIG. 2 , prior to tearing locator strip  40  away from assembly  10 . As illustrated in  FIG. 3 , first and second stitching lines  20  and  30  extend substantially in parallel proximate an interface of locator strip  40  and attachment strip  50 . The interface of locator strip  40  and attachment strip  50  comprises an overlapping region  60 , also shown in  FIG. 5 . First stitching line  20  is preferably formed such that it pierces both of locator strip  40  and attachment strip  50 , whereas second stitching line  30  preferably pierces only attachment strip  50 . 
     Further illustrated in  FIG. 3  are retention members or clips  70 . In a preferred embodiment, clips  70  snap fit with enlarged edge portion  51  of attachment strip  50 , and assist in retaining attachment strip  50  in the target groove. Clips  70  are preferably attached to backing member  12 , within groove  14 , and the seat cover assembly lowered into engagement with backing member  12 , snap fitting attachment strip  50  into engagement with clips  70 . Various designs are contemplated wherein clips  70  are positioned at varying locations along the groove in the seat backing, allowing the cover assembly  10  to be secured at selected points. For example, portions of vehicle seats exposed to relatively greater mechanical stress and strain may call for a relatively securely attached cover assembly at that point, requiring one or more clips. Other regions may require or be better suited to a degree of play between the covering and the backer and may thus require fewer or no clips  70 . 
     Turning now to  FIG. 4 , there is shown an alternative embodiment of the present invention including an attachment strip  150  having an alternatively shaped head  151 . Many variations might be made to the design and structure of attachment strip  50 ,  150 . It is generally preferred, however, to provide a strip having a shape that facilitates mating engagement with fasteners or clip members  70 . 
     By providing a design having a plurality of fasteners  70 , preferably slidable relative to enlarged portion  51 ,  151 , seat cover assembly  10  can be securely attached to seat backing member  12  at a plurality of selectable positions along a length of strip  50 ,  150 . Moreover, a sliding interface between clips  70  and attachment strip  50  provides for some “play” between the clips  70  and secured cover assembly  10 , reducing wear on the seat in some instances, and compensating for slight variations from the prescribed fastening of the seat cover  10  to the seat backing  12  during manufacturing. Thus, where attachment strip  50 ,  150  is not perfectly positioned relative to a particular supporting clip  70 , the relative position of the cover assembly  10  with respect to the seat backing  14  can be adjusted slightly without disengaging the cover assembly  10  therefrom. 
     Further advantages of the present design include the capacity for “two-way” assembly of seat covers with seat backing members. For example, because an operator can grasp locator strip  40 , entry of the edges of upholstery panels  11 A and  11 B into groove  14 , along with attachment strip  50 , can be made from either of opposite sides of groove  14 . Variations in the design of interior upholstered members in vehicles makes it desirable in some instances to be able to attach the upholstery cover from different angles or sides of the groove  14 . 
     The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present invention in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the spirit and scope of the invention. Other aspects, features, and advantages will be apparent upon an examination of the attached drawing Figures and appended claims.