GB2114051A - Moulding fabric covered plastics foam assemblies - Google Patents

Abstract

A fabric covered plastics foam assembly, such as a vehicle seat, is formed by inserting in a mould 18, 22, 24 a pre-formed unit 10 comprising a fabric cover having on one side a layer of plastics foam, or individual pieces of foam, secured to the fabric cover, so that the foam side of the unit 10 defines part of the mould cavity 26, then filling the mould cavity with foaming plastics which is allowed to set so that a product is produced, for example, a vehicle seat, in the form of a foam block, having a fabric surface afforded by the unit 10. In making the pre-formed unit 10, the fabric cover is contoured over the plastics foam layer or pieces, for example by stitching, so that the finished product has a correspondingly contoured surface. Further members, such as a backing pate 28, may also be incorporated with the foam plastics. <IMAGE>

Description

SPECIFICATION Fabric Covered Plastics Foam Assemblies This invention relates to fabric-covered plastics foam assemblies, and to a method of, and apparatus for producing such assemblies.

The invention is of particular, but not exclusive applicability to the production of fabric-covered flexible foam assemblies with a high styling content for use in automotive and similar seating applications.

In a typical known procedure for the assembly of, for example, a seat back or seat base for a motor vehicle, a covering fabric is flame laminated to a layer of polyurethane ester foam approximately 8 or 10 mm thick with a nylon or cotton scrim backing being provided on the foam layer to provide stitch strength. The resulting laminate is usually back printed for dye batch identification, and is subsequently press cut to shape, then straight line sewn for styling detail and sewn together and to a fabric skirt to form a seat cover.

Such a cover complete with sewn-in pull down assemblies is then pulled over a plastics foam moulding which in turn is fitted to a metal seat frame and suspension unit. The whole is held in position by means of the pull down assemblies and skirt clips.

This construction procedure is very labour intensive, needs considerable expertise in dye batch control, and is restrictive, as regards styling innovation because of the limitations of straight line sewing.

Various attempts have been made to date within the vehicle seating industry to develop a fully moulded seat assembly in which the facing fabric is introduced into the mould cavity. The processes heretofore proposed have been restricted by basic process problems and so have never been adopted in any volume by the automotive and other styling-conscious markets.

Among the limitations of the heretofore proposed processes are the features that the range of fabrics offered has been limited to those having adequate extensibility and suitability of moulding and factors determined by the need to cover the fabrics with an impervious layer to permit vacuum forming and to provide a barrier to prevent foam penetration during moulding. Moulded designs offered to stylists have been very basic, any design change incurring a high tooling charge.

It is among the objects of the present invention to provide a method and apparatus by which the above noted disadvantages may be avoided.

According to one aspect of the invention there is provided a method of producing a fabriccovered plastics foam assembly comprising extending across at least one wall of a mould a pre-formed unit affording on one face thereof adjoining said wall of the mould a fabric layer and disposed on the side of said fabric layer remote from said one wall a layer of, or individual pieces of, plastics foam, said pre-formed unit being so formed as to provide on the side of the pre-formed unit afforded by said fabric layer, a contoured or styled surface, the method further comprising closing the mould and passing into the mould, in a liquid or flowable condition, material adapted to foam within the mould to fill the space within the mould on the side of said preformed unit remote from said one wall with foam plastics material, to afford a unitary core of plastics foam, and subsequently opening the mould when the foam plastics has solidified and removing the assembly therefrom.

According to another aspect of the invention there is provided apparatus for use in performing the method of the invention, including a mould having at least two parts defining, in a closed condition of the mould, respective parts of the surface of a mould cavity, one of said parts defining one wall of said mould cavity and at least one other of said parts defining an adjoining wall of the mould cavity which extends all around the periphery of said one wall, said one and said other of said parts being separable from one another along opposing parting surfaces.

The invention also comprises within its scope a fabric-covered plastics foam assembly, such as a vehicle seat or part thereof, produced by the method of the invention or using the apparatus of the invention.

The references herein to plastics foam are intended to include not only materials generally considered as such, for example foamed polyurethane, polyethylene and the like, but also, for convenience, foamed elastomeric materials such as natural or synthetic rubber.

The term "fabric", as used herein, is likewise intended to cover not only woven textiles and materials formed of knitted yarns, but other flexible sheet materials suitable for upholstery purposes, such as sheet plastics sheet material formed of non-woven fibres, and various composite sheet materials.

An embodiment of the invention is described below, by way of example, with reference to the accompanying drawings in which:~ FIGURE 1 is a schematic sectional view showing the production of a fabric-covered foam seat member in a mould, by a method embodying the invention, and FIGURE 2 is a schematic perspective view of a fabric-covered foam seat member.

Referring to the drawings, a fabric-covered flexible foam assembly, for example the back part of a car seat, such as shown at 8 in Figure 2, comprising a fabric front panel 10 and a skirt 12 connected along a seam 14 with the periphery of the front panel 10 and extending between the front panel 10 and the rear surface, (not shown in Figure 2), of the seat back, is produced as follows.

The front panel 10 is contoured or patterned in relief, principally for decorative reasons, to afford a plurality of raised areas or panels separated by linear depressions or grooves to afford an effect known per se. In the manufacture of the assembly, the front panel 10 is first formed as a preformed unit, for example by sandwiching between a facing fabric and a backing fabric a layer of plastics foam and stitching or welding the facing fabric and backing fabric together through the foam along the desired lines to produce the desired depressions between the raised areas in the finished front panel, or by confining separately formed blocks of plastics foam between the facing fabric and a backing fabric in pockets formed by stitching or welding the facing and backing fabric together along the desired lines.Alternatively, the pre-formed unit may be formed by a method affording an equivalent effect without stitching, such as that disclosed in British Patent Specification No. 1,1 45,87 5.

The pre-formed unit is then laid over a support block 18, forming a first part of a mould in which, ultimately, a monolithic foam block forming the core of the seat member is ultimately moulded, the unit 1 0 being disposed with the facing fabric thereof engaging the upwardly presented surface of the block 18. This upwardly presented surface is formed to approximately the desired overall configuration of the front surface of the part 8, but does not conform exactly with the opposing surface of the premoulded unit 1 0, insofar as it is unnecessary to provide the surface of the support block with formations extending within each of the grooves between adjoining raised areas on the front of the unit 10.A skirt 12 may be attached, for example by sewing or welding along seam 14, to the unit 10, prior to fitting the unit 1 0 over the support block, in which case the skirt 12, (in a reversed condition) may extend down over the sides of the support block 18 as shown in Figure 1. In some cases, it may be preferred to secure the skirt 1 2 to the border of the unit 1 0 after moulding of the foam core. In either case, the arrangement is such that when the unit 10 is fitted over the support block 18, the edge portion or border of the unit 1 0 projects over the periphery of the support block 18.

The mould further includes a second mould part 20, comprising a side member 22 which extends all around the sides of the mould cavity, and a top plate 24 which closes off the upper end of the mould cavity. When the unit 1 0 has been fitted over block 18, the member 22 is then fitted over the support block 18 so that the lower peripheral portions of the member 22 engage the border of the unit 10, so that said border is clamped sealingly between the member 22 and the support block 18. The plate 24 may already be fitted to the member 22 when the latter is applied to block 18 or may be fitted subsequently.When the mould cavity has thus been closed, there is introduced into the space 26 defined between the back of the unit 10 and the mould parts 22, 24, plastics material in a liquid orflowable condition incorporating foaming agents, the plastics material foaming and subsequently curing within the cavity 26 to form a unitary foam core, whereafter the mould is opened and the unit -10, having adhered thereto the core of foamed material moulded in the space 26, is removed from the mould. The foam core has its back contoured as desired by the complementarily formed bottom surface of top plate 24. The skirt 1 2 is then drawn back over the sides of the foam core and is secured, around its longitudinal edges remote from the front 10 to a back member or back panel.Where the foam core is moulded before the attachment of the skirt 12 to the unit 1 0, the skirt 12 is stitched to the border of the unit 10, (which extended outside the mould cavity during foaming), after removal of the unit 10 with the foam core, etc. from the mould.

The back of the seat part 8 may be afforded wholly, or in part, by a contoured backing plate 28 which may be solid or flexible and which may be adapted for securing to a frame member of the finished seat, or may itself constitute such a frame member or may simply serve as an attachment for a further trim plate or the like (not shown). In manufacture of the assembly, the plate 28 is detachably secured to the lower face of the top plate 24 before the mould is closed, and so is present within the mould cavity during foaming of the plastics material and is thus bonded to the foam core. In the arrangement shown, the plastics material is fed into the mould cavity via filling gates 30 formed on the top plate 24 and from which sprue passages 32 extend to the lower face of the plate 24.The back plate 28, where utilised, is formed with apertures, in register with the passages 32, to allow passage of the plastics material into the mould cavity.

In a variant, a suitably contrived mounting frame, adapted to support the foam core and at the same time to form part of the frame of the seat, may be supported in readily detachable fashion, within the mould cavity from the top plate 24, the frame affording appropriate attachment points whereby the frame can be secured to the remainder of the seat structure or to the vehicle body etc.

The skirt 12 may, if preferred, be sewn, welded, or otherwise attached to the boundary of the unit 1 0 before moulding of the foam core, and the unit 10 with the attached skirt fitted into a mould recess corresponding to that defined between the members 22 and 18 x hen engaged with one another, before the top plate 24 is applied, in such a way that the skirt 1 2 lies within said recess adjacent the peripheral wall afforded by the part 22 in Figure 1. If desired, in this variant, the free edge of the skirt 1 2 may be extended between the member 22 and top plate 24, to be gripped sealingly thereby when the mould is closed by lowering the top plate 24.

It will be appreciated that for the variants in which the skirt 12 or the border of unit 10 is kept outside the mould cavity during moulding of the foam core, it is not strictly necessary for the member 22 to be separable from the top #plate 24, whilst in cases where the skirt 12 is to be kept within the mould cavity it is not necessary for the member 22 and the support block 18 to be separable. However, by making the member 22 separable both from the support block and the top plate, the mould is made more versatile and is adaptable to variations in seat design. The regions where the member 22 and the block 18 and plate 24 meet are, of course, so formed as to afford an adequate seal, with or without a fabric layer interposed.

The contours of the upper surface of the support block 18 may, if desired, be afforded by simple filling pieces or the like screwed to the main block, which pieces can readily be replaced by others of different configuration or in different positions, to accommodate design changes very readily, and these filling pieces, since they serve principally to afford mechanical support for the unit 10, rather than to mould the latter to a desired shape need not be made to a very high degree of accuracy nor be finely finished, and can thus be made and modified at little expense.

The mould 18, 22, 24 may be incorporated into, and the described method performed, using a conventional foam moulding system, either of the carousel type or a more traditionally designed conveyor system, as will be evident to those skilled in the art.

The preferred methods described with reference to the drawings afford considerable advantages as compared with the conventional method of making seats for motor vehicles and the like, and yet avoid many of the disadvantages of previously proposed methods involving the foaming of plastics material in contact with a seat cover. Thus, the preferred method described with reference to the drawings, permits the use of conventional facing material so that the choice of materials is notrlimited by special requirements determined by the moulding process. The need for coating the back of the facing fabric or laminating the same with an impervious material, in order to ensure that the facing fabric is impervious to the foaming plastics material can be eliminated.However, in certain applications, the inclusion of such an impervious material can result in a superior product when the method of the invention is utilized. Furthermore, it is readily possible to utilise a different foam material in the pre-moulded unit than for the foam core, and, indeed it is possible to utilise different foam materials for different parts of the pre-moulded unit. Thus, for example, it is possible to include high density foams in critical areas such as the seat side rolls. The possibility of incorporating, within the foam core, or intimately engaged therewith, base or back boards and/or support frames, mounting assemblies or the like is also advantageous.

The inserted fabric, or fabric/foam composite, components, such as unit 10, may be held in place in their desired positions in the mould cavity, in close contact with the respective internal-surfaces of the mould, by vacuum, in a manner know per se, with the respective mould surfaces being formed with apertures connected via channels in the mould with a vacuum source. Where vacuum is employed in the manner, this incorporation of an impermeable layer in the fabric faced components, such as unit 10, may be advantageous.

The methods described with reference to the drawings also have substantial advantages when utilised in conjunction with pre-formed units made by the method of British Patent Specification No.

1,145,875. Thus, the need for conventional flame lamination is eliminated as is the need for back marking and the problems associated with dye batch control are alleviated. Furthermore, a considerable and relatively unrestricted styling potential is afforded.

Whilst, for convenience orientational terms such as upper, lower, top, bottom etc. have been used in the foregoing description in relation to the mould, it will be appreciated that it is not thereby intended to imply any limitation as to orientation in practice, and the mould and parts thereof may, of course, be disposed in any orientation depending upon the requirements of the manufacturing installation.

Although the embodiments described with reference to the drawings relate to the manufacture of the back part of a vehicle seat, it will be appreciated that the method is equally applicable to the manufacture of other items, including, in addition to the base parts of such seats, such items as fabric faced door panels, or other upholstered items.

Claims (1)

1. A method of producing a fabric-covered plastics foam assembly comprising extending across at least one wall of a mould a pre-formed unit affording on one face thereof adjoining said wall of the mould a fabric layer and disposed on the side of said fabric layer remote from said one wall a layer of, or individual pieces of, plastics foam, said pre-formed unit being so formed as to provide on the side of the pre-formed unit afforded by said fabric layer, a contoured or styled surface, the method further comprising closing the mould and passing into the mould, in a liquid orflowable condition, material adapted to foam within the mould to fill the space within the mould on the side of said pre-formed unit remote from said one wall with foam plastics material, to afford a unitary core of plastics foam and subsequently opening the mould when the foam plastics has solidified and removing the assembly therefrom.

2. A method according to claim 1 wherein said pre-formed unit comprises a border of said fabric, and wherein the mould is so contrived that in the closed condition of the mould, with the preformed unit therein, said border is engaged sealingly between the part of the mould providing said one wall, and the part or parts providing the adjoining wall or walls, whereby said border, during the mould filling and foaming operations is kept out of contact with the plastics material supplied to the mould.

3. A method according to claim 2 wherein the mould is so contrived that, in said closed condition of the mould, said border extends from the mould.

4. A method according to claim 3 or claim 4, wherein a fabric skirt is secured to said border after removal of the assembly from the mould, said skirt, in the finished assembly forming part of the covering of said unitary core of plastics foam.

X ' 6. A method according to claim 3 wherein a fabric skirt is secured to said border of said preformed unit before the latter is extended across said one wall of the mould.

7. A method according to any preceding claim wherein an insert in the form of a back board or mounting frame for the assembly is fitted in the mould cavity prior to moulding.

8. A method according to claim 7 wherein said insert is in the form of a back board and is disposed adjacent that wall of the mould cavity which, when the mould is closed, opposes said one wall.

9. A method according to claim 7 wherein said insert is a mounting frame and is secured detachably to the part of the mould which provides, when the mould is closed, the wall of the mould cavity which faces said one wall.

10. A method according to any preceding claim wherein said foam assembly is a seat for a motor vehicle or a part of such a seat.

11. Apparatus for use in performing the method of any preceding claim and including a mould having at least two parts defining, in a closed condition of the mould, respective parts of the surface of a mould cavity, one of said parts defining one wall of said mould cavity and at least one other of said parts defining an adjoining wall of the mould cavity which extends all around the periphery of said one wall, said one and said other of said parts being separable from one another along opposing parting surfaces.

12. A method according to claim 1 wherein said pre-formed unit has, secured around a border of said fabric, a fabric skirt which extends around the mould cavity closely adjacent a peripheral wall which adjoins said one wall, said fabric skirt being sealingly engaged, when the mould is closed around its periphery remote from said pre-formed unit, between, on the one hand the portion of the mould providing said one wall and said peripheral wall, and, on the other hand, a portion of the mould affording a further wall opposing said one wall, the foamable plastics material being introduced into the mould through one or more openings in said further wall.

13. A fabric-covered plastics foam assembly manufactured by the method of any of claims 1 to 12 or using the apparatus of claim 1 1

14. A vehicle seat or part thereof manufactured by the method of any of claims 1 to 12 or using the apparatus of claim 11.

15. A method of producing a fabric-covered plastics foam assembly, substantially as hereinbefore described with reference to the accompanying drawing.

16. Apparatus for use in producing a fabriccovered plastics foam assembly, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

17. A vehicle seat or part thereof manufactured bythe method of claim 14 and using the apparatus of claim 15.

18. Any novel feature or combination of features described herein.