Seam stabiliser for covers of foam bodies

Abstract: A tear away seam stabilizer for a vehicle seat component is provided for use with the pour-in-place molding process. The stabilizer, or welt, has an annular body (12) attached to a notched tab portion (14) by a tapered portion (16) and neck portion which is sewn between covering members (20) to form the desired shape of a seat component. A mold is provided within which the sewn cover, with the seam stabilizers in place, is inserted. The stabilizers maintain alignment of the seams in the cover member during the pour-in-place process and also prevent wrinkles in the cover. The end result is a vehicle seat component with the cover member tightly adhered to the foam body and conforming to a surface of predetermined shape. Once the foam pad is adhered to the cover member, the annular body of the stabilizer is readily torn off.

Description: This invention relates generally to covers for foam parts of vehicle seat assemblies, such as the seat members and headrests, and more particularly to such foam parts which are improved from the standpoints of comfort and appearance by virtue of the use of the seam stabilizers of this invention in the covers for these parts. It is a desirable objective in seating of all types, particularly vehicle seating, to provide seat components with covering materials which conform tightly to the surface of the foam pads. Such seat members are desirably formed with an interior load support section bounded by peripheral sections that function as bolsters to impart a feeling of stability and comfort to the occupant of the seat. The interior sections should further include a contoured surface to enhance the seat cushion's appearance and occupant's comfort. In order to accomplish this, the present invention utilizes separate covering members to cover the interior section and the peripheral sections of the seat member. The separate covering members are secured in place by the attachment of these members to a tear away welt, or trim strip, which is integrated into a seam at the juncture of the sections, thereby stabilizing the seam and preventing wrinkling of the cover during the pour-in-place molding process of the foam pad. Tear away welts have previously been used in the manufacture of vehicle seats, as shown by US-A-4 765 045, assigned to the assignee of this application. However,the welt shown in the patent is for seam locating purposes, not seam stabilising. The abovementioned patent teaches the use of the welt to position the covering material on a mould and subsequently on a pre-shaped pad. FR-A-2 262 588 discloses a method of manufacturing a component of a vehicle seat assembly. This component comprises a foam body and a cover for the body. The cover comprises a main face portion, to which are secured further portions. The main and further portions are secured together using a welt having a tear-away body and tab portion. To mould the foam body, the main face portion of the cover is positioned in a mould cavity and expandable liquid foaming material is introduced into the cavity to bond to the main face portion. To avoid bonding between the foaming material and the further portions of the cover, these further portions are excluded from the mould. According to one aspect of the present invention, there is provided a method of manufacturing a composite component of a vehicle seat assembly consisting of a foam body of predetermined shape and a cover for said body, said cover consisting of at least two cover members connected at a seam and at least one welt having a tear away body portion and a tab portion, the tab portion of said at least one welt being secured between said cover members at said seam, said method comprising the steps of: (a) providing a mould member having a cavity corresponding in shape to said predetermined shape of said foam body; (b) placing said cover members in said mould member so that said cover corresponds to the shape of said cavity; (c) moulding said foam body in place upon said cover members by pouring in place an expandable liquid foaming material on said cover members within said mould member in such a manner that said foam body is bonded to said cover members and conforms in shape to said predetermined shape; (d) removing said foam body from said mould cavity with said cover members bonded to said foam body; and (e) removing said body portion of said at least one welt. According to another aspect of the present invention, there is provided a component portion of a vehicle seat assembly, comprising a moulded foam body of predetermined shape, a cover covering said foam body and including a first cover member and a second cover member, and a welt secured between said first and second cover members and including a portion encapsulated within said foam body, characterised in that said foam body is integrally bonded to both of said first and second cover members. In contrast to US-A-4 765 045, the welt is not secured to the mould and a pre-shaped foam pad is not required. Rather, a pour-in-place process is used to form the foam pad. There are several benefits from using the pour-in-place process to mould the foam pad instead of using a pre-shaped pad. For example, the overall production cost is lower since the step of attaching the foam pad to the cover is eliminated. Additionally, the difficulties associated with aligning a pre-shaped pad with a shaped cover are non-existent in the pour-in-place process, thereby resulting in a better fitting cover and a faster production process. The tear away welt is preferably moulded of bendable plastic material, however, other materials providing sufficient rigidity may also be used. Initially, the welt is sewn into the covering members at their junctures, so as to stabilise the resulting seams and ensure that the seam will maintain the desired shapes. A first mould member supports the covering members, and the welt, prior to moulding of the foam pad. A second mould member is then positioned above the first mould member and a liquid foam material is injected into the mold cavity onto the cover members to form the foam pad to the cover assembly. The tear away welt provides accurate location of the covering members in the mold during the injection of the liquid foam material and also prevents the seams from moving and being out of alignment. The above mentioned welt has an annular body, positioned outside the seat component during assembly, and a notched tab portion, remaining within the seat component after assembly. At the juncture of the notched tab portion with the annular body, the welt is tapered to a reduced thickness to facilitate sewing and tearing. Once the foam pad has been poured and formed within the mold, the covering members become adhered to the foam pad. The covering members and foam pad are then removed from the mold and the annular body portion of the tear away welt strip may be removed, if desired, by tearing it away from the notched tab portion. The result is a vehicle seat component in which the covering members are tightly adhered to the foam pad and conformed to the surface irregularities and designs of the foam pad. If desired, the interior and peripheral covering members can be formed of contrasting materials since different covering members are used in covering foam parts with this invention. The result is an apparatus and a process that is improved from the standpoints of reliability in quality assurance and a seat product that is improved from the standpoints of appearance and comfort. Other features of the invention are set out in claims 2-7 and 9-12. Further objects, features and advantages of the invention will become apparent from the consideration of the following description, the appended claims and accompanying drawings in which: Figure 1 is an enlarged elevational view of the tear away seam stabilizing welt of this invention; Figure 2 is an enlarged fragmentary side view of the tear away welt shown in Figure 1; Figure 3 is an enlarged sectional view of the tear away welt attached to the cover members; Figure 4 is a transverse sectional view of the mold with the cover materials and welt assembled; Figure 5 is a transverse sectional view of the mold with the cover materials, welt and injected foam material assembled; Figure 6 is a transverse sectional view of a seat member incorporating the tear away welt of this invention after final assembly; Figure 7 is a perspective view of another seat member, a head rest, with the tear away welt of the present invention being removed; Figure 8 is a partially cut away perspective view of the mold with the cover materials, welts and injected foam material assembled into a head rest seat member; Figure 9 is an elevational side view of another embodiment of the tear away welt of the present invention; and Figure 10 is a cross-sectional view taken generally along lines 10-10 in Figure 9 of one embodiment of the tear away welt of the present invention. With reference to the drawings, the tear away welt of the claimed invention is shown in Figures 1 and 2 and generally designated 10. The welt 10 has an elongated annular body portion 12 connected to an elongated tab portion 14 through a tapered portion 16 and a neck portion 17. The tapered portion 16 and neck portion 17 allow seat cover portions 20 to be secured together and the annular body 12 to be removed from the tab portion 14 during final assembly, as discussed in detail below. The tab portion 14 also has notched portions 18 to increase flexibility of the welt 10. A seat member component of the present invention is manufactured in the following manner. The seat cover portions 20 and 20 are sewn or otherwise secured together through the welt 10 at the neck portion 17, as shown in Figure 3. Once all of the seat covering portions 20 are sewn together, a unitary seat covering member 22 is formed with welts 10 located at the junctions or seams of the cover portions 20. The cover member 22 can be formed of any fabric or other material used to cover seats. It is to be understood that the unitary seat covering member 22 can be substantially any shape desired for the seat member, regardless of whether that seat member is a seat cushion, seat back, head rest, arm holster or other trim assembly. In the preferred embodiment, the seat cover 22 has an interior load support section 28 and an outer section 30 which extends around the periphery of the interior section 28. The sides of the outer section 30 function as bolsters and the front (not shown) functions as a thigh support and extends between the forward ends of the bolsters. The interior section 28 is contoured to provide a plurality of supports 32 which perform the double function of improving the appearance of the seat and sectionalizing the foam pad 36 for improved comfort purposes. If desired, the juncture of the supports 32 could also be defined by welts 10. The foam pad 36 of the present invention is manufactured using the pour-in-place method, as disclosed in U.S. Patent Application No. 205,929 filed June 13, 1988, which is hereby incorporated by reference. The pour-in-place method utilizes a mold member 25 having first and second members 24 and 26 forming a mold cavity therebetween. The first mold member 24 defines the load engaging surface of the foam pad 36 and corresponds to the load engaging surface 28 of the seat cover member 22. After forming the seat cover member 22 by securing the cover portions 20 to the welts 10, the cover member 22 is placed in the first mold member 24 as shown in Figure 4. The edges 31 of the cover member 22 extends beyond the cavity 33 of the mold member 25. A seat support frame 29 is mounted in the second mold member 26. Alternatively, the support frame 20 could also be assembled into the seat member at a later time. The second mold member 26 is then lowered into position above the first mold member 24, as shown in Figure 4, with the free edges 31 of the cover member 22 extending beyond the mold 25. In this position, the support frame 29 is spaced apart from the cover member 22 forming a foaming cavity 33 therebetween. An expandable liquid foam material is injected into the foaming cavity 33 and onto the cover member 22 through an opening (not shown) in the mold member 25. In so doing, a foam pad 36 is molded which is integrally bonded to the seat cover member 22 and has embedded therein a portion of the support frame 29. Without the welts 10 located within the cover member 22, the juncture of the cover members 20 and 20 would have a tendency to shift during this pour-in-place process. Therefore, the welt 10 ensures that the cover member 22 will have straight seams for further visual enhancement of the seat member. Figure 8 displays an analogous mold configuration for forming a head rest and is designated with like references. Figure 5 shows the assembly comprising the foam pad 36 having a portion of its support frame 29 embedded therein and having the seat cover member 22 bonded thereto. After a brief period, the cover member 22 is firmly adhered to the pad surface so that the pad 36, with the cover member 22 thereon, can be removed from the mold 25 and the free edges 31 of the cover member 22 can be secured in any desired manner to the foam pad 36, such as hog rings 37 extending around the support frame 29 and retaining wires 38 embedded in the edges 31 of the cover member 22. As stated earlier, the tear away welt 10 has an annular body portion 12, neck portion 17 tapered portion 16 and tab portion 14, secured at the juncture of the cover portions 20. The annular body 12 can be readily torn from a finished seat component 40 by simply grasping the welt 10 and manually removing the body portion 12 from the tab portion 14. Figure 7 shows the annular body 12 being torn away from a finished seat component 40, a head rest. The elongated tab portion 14 remains hidden from view in the finished seat component 40. Another embodiment of the present invention is shown in Figure 9 and Figure 10. A tear away welt 50 has an annular body 52 circumferentially enclosed in thin plastic sheeting 54. The sheeting 54 is secured around the annular body 52 by stitching 56, or other suitable fastening means, forming an elongated tab portion 55. Cover members 20 and 20 are then sewn or otherwise secured together through the welt 50 along the stitching 56 line to form a unitary cover 22. The seat component is then constructed according to the method previously described. From the above description it is seen that this invention provides a vehicle seat component having interconnected cushion and covering members which are formed to enhance comfort of the occupant and appearance of this seat. If desired, the interior section and peripheral sections of the cover can be formed of contrasting materials or contrasting colors to further enhance the appearance of the seat member.

Claims: A method of manufacturing a composite component (40) of a vehicle seat assembly consisting of a foam body (36) of predetermined shape and a cover (22) for said body, said cover consisting of at least two cover members (20) connected at a seam and at least one welt (10,50) having a tear away body portion (12) and a tab portion (14), the tab portion of said at least one welt being secured between said cover members at said seam, said method comprising the steps of: (a) providing a mould member (24) having a cavity (33) corresponding in shape to said predetermined shape of said foam body (36); (b) placing said cover members (20) in said mould member (24) so that said cover (22) corresponds to the shape of said cavity (33); (c) moulding said foam body (36) in place upon said cover members (20) by pouring in place an expandable liquid foaming material on said cover members within said mould member (24) in such a manner that said foam body is bonded to said cover members and conforms in shape to said predetermined shape; (d) removing said foam body (36) from said mould cavity (33) with said cover members (20) bonded to said foam body; and (e) removing said body portion (12) of said at least one welt (10,50). A method as claimed in claim 1, wherein said cover (22) comprises an interior section (28), outer sections (30) on transversely opposite sides of said interior section, and a plurality of said welts (10,50) secured at the junctures of said interior section with said outer sections. A method as claimed in claim 2, comprising the steps of: (a) forming a first covering member of a size to cover a portion of said foam body (36) corresponding to said interior section (28) of said cover; (b) forming second covering members of a size to cover portions of said foam body (36) corresponding to said outer sections (30) of said cover; and (c) securing a said welt (10,50) between peripheral edges of said first member and a corresponding edge of said second members to form said cover (22). A method as claimed in any of the preceding claims, wherein the or each said welt (10,50) comprises an annular body (12,52) being removable from said seat component and a tab portion (14,55) which remains with said seat component enabling tearing of said welt and facilitating removal of said annular body. A method as claimed in any of the preceding claims, wherein the or each said welt (10) is formed of a bendable plastics material with a reduced thickness section (17) to enable tearing and facilitate removal of said body portion (12) of the welt. A method as claimed in claim 4, wherein said tab portion (55) of said welt (50) consists of a plastic sheet (54) secured around said annular body (52) and sewn to said cover members (20). A method as claimed in any of the preceding claims, further comprising a component support frame (29), wherein said at least two cover members (20) are positioned within a first portion (24) of said mould member having a shape complementary to said predetermined shape of said foam body (36), with edges (31) of said cover members (20) extending beyond said lower mould member; said component support frame is mounted to a second portion of said mould member; said second mould member portion (26) is placed over said first mould member portion (24) to create said cavity (33) between said cover members (20), said second mould member portion and said component support frame (29); said expandable liquid foaming material is poured into said cavity (33) to mould said foam body (36) in such a manner that said foam body encapsulates a portion of said component support frame (29); said foam body (36) is removed from said mould member with said cover members (20) bonded thereto and said component support frame (29) partially encapsulated therein; and said edges (31) of said cover members (20) are then attached to said component support frame (29). A component portion of a vehicle seat assembly, comprising a moulded foam body (36) of predetermined shape, a cover (22) covering said foam body and including a first cover member (20) and a second cover member (20), and a welt (10,50) secured between said first and second cover members and including a portion encapsulated within said foam body, characterised in that said foam body (36) is integrally bonded to both of said first and second cover members (20). A component portion as claimed in claim 8, wherein said welt (10,50) includes an elongated annular body (12) connected to an elongated notched tab portion (14), said tab portion being encapsulated within said foam body (36). A component portion as claimed in claim 9, wherein said annular body (12) is connected to said tab portion (14) through a tapered and necked portion (17), said tapered and necked portion having said first and second cover members (20) secured therethrough an enabling said annular body to be removed from said component portion. A component portion as claimed in claim 10, wherein said annular body is retained with said component portion. A component portion as claimed in claim 10, wherein said annular body is removed from said component portion.

Inventors: SMITH SANDRA L, SMITH, SANDRA L.
Applicants: HOOVER UNIVERSAL, HOOVER UNIVERSAL INC.
Application year: 1991
Main classification: B68G7
IPC codes: B68G7, B29C39, A47C7, B29L9, B29L31, B29K105, B29C44