EP0467785B1 - Method for manufacturing and fastening a seat upholstery on a seat frame - Google Patents

Abstract

In this upholstery, the soft external sheet (4) covering the covering layer (3) projects laterally in relation to this layer by a sufficient width to be turned down onto a seat support and be rendered integral therewith. <IMAGE>

Description

The present invention relates to a method of fixing a flexible lining on a seat support.

• 1) Une couche de couverture en matière plastique compacte, relativement épaisse, qui, en raison de son épaisseur et de sa compacité, constitue un premier obstacle à la lacération. Cette couche de couverture, qui n'est soumise à aucun effort quelconque en tension, présente une faible élasticité dans son plan, mais une bonne flexibilité.
• 2) Un réseau, formé d'une nappe continue de ressorts métalliques hélicoïdaux, dont les axes sont sensiblement parallèles à la couche de couverture en matière plastique compacte et dont les spires sont entremêlées les unes avec les autres, de manière à obtenir, vue en plan, une structure en forme de damier, à mailles très extensibles, permettant de stopper la pénétration et la progression d'un objet tranchant, les spires desdits ressorts venant, d'un côté, sensiblement affleurer la face inférieure de la couche de couverture.
• 3) Une couche intermédiaire de liaison entre la couche de couverture et la nappe de ressorts, cette couche étant réalisée en une mousse de matière plastique d'épaisseur inférieure au diamètre des spires des ressorts de ladite nappe, qui adhère, d'un côté, à la face inférieure de la couche de couverture en matière plastique compacte et qui enrobe en partie les spires de la nappe de ressorts, sur une fraction de l'épaisseur de cette nappe.

In FR-A-2 447 167, the Applicant has described a lining for a seat, in particular for a seat of a public transport vehicle, intended to resist vandalism and, more particularly, laceration. This garnish includes at least three distinct elements, namely:

• 1) A relatively thick, compact plastic cover layer which, due to its thickness and compactness, constitutes a first obstacle to laceration. This covering layer, which is not subjected to any stress whatsoever in tension, has a low elasticity in its plane, but good flexibility.
• 2) A network, formed of a continuous sheet of helical metal springs, the axes of which are substantially parallel to the cover layer of compact plastic material and the turns of which are intermingled with one another, so as to obtain, seen in plane, a structure in the form of a checkerboard, with very extensible meshes, making it possible to stop the penetration and the progression of a sharp object, the turns of said springs coming, on one side, substantially flush with the underside of the covering layer.
• 3) An intermediate bonding layer between the covering layer and the sheet of springs, this layer being made of a plastic foam of thickness less than the diameter of the turns of the springs of said sheet, which adheres, on one side, to the underside of the cover layer of compact plastic material which partially coats the turns of the sheet of springs, over a fraction of the thickness of this sheet.

The external face of this lining may possibly be covered with a flexible external sheet of decorative material, for example fabric.

• la découpe de la garniture à la forme et aux dimensions désirées ;
• le dépôt, à une légère distance de la bordure périphérique, du côté où fait saillie la nappe de ressorts, d'un cordon en matière plastique possédant des propriétés d'élasticité, ce cordon venant adhérer sur la couche intermédiaire en mousse de matière plastique et venant enrober, en la dépassant, la partie de la nappe de ressorts sortant de cette couche intermédiaire ;
• la mise en place de la bordure périphérique de la garniture dans un moule périphérique, qui présente une cavité dans laquelle pénètre cette bordure, l'étanchéité entre la garniture et le moule étant assurée, d'un côté, par le contact de la paroi du moule avec la face extérieure de la garniture et, de l'autre côté, par le contact de la paroi du moule et du cordon d'étanchéité, et
• l'introduction d'une matière plastique appropriée à l'intérieur du moule.

A method of manufacturing a seat element by molding of a frame on such a lining is described, for example, in international patent application No. WO 85/03420, in the name of the Applicant. This process includes the following phases:

• cutting the filling to the desired shape and dimensions;
• the deposition, at a slight distance from the peripheral edge, on the side where the spring ply projects, of a plastic cord having elasticity properties, this cord adhering to the intermediate layer of plastic foam and coming to coat, by exceeding it, the part of the sheet of springs leaving this intermediate layer;
• placing the peripheral edge of the lining in a peripheral mold, which has a cavity into which this border penetrates, the seal between the lining and the mold being ensured, on one side, by the contact of the wall of the mold with the outside face of the lining and, on the other side, by the contact of the mold wall and the sealing bead, and
• the introduction of a suitable plastic material inside the mold.

This process, although perfectly satisfactory on the technical level, is however relatively expensive due to the necessary tools. In addition, because of its method of manufacture and its low elasticity, it is difficult to give this filling the rounded shapes which are sometimes requested.

By continuing its work on a trim of the above type, the Applicant has been led to design a variant of this trim, which lends itself to easy mounting on a seat frame and to the use of noble covering materials, such as as leather, velvet or other, which allow its use with interior seats of various types and not only with seats of public transport vehicles.

More specifically, the invention aims to provide a method of manufacturing and fixing a lining on a seat support, which uses a particularly simple method of fixing on this frame.

• on dépose sur un support transfert une couche de résine mélangée à un agent d'expansion ;
• on noie partiellement dans cette couche la nappe de ressorts,
• on provoque la polymérisation et l'expansion au moins partielle de la résine en laissant dépasser les ressorts de la couche du polymère expansé ainsi obtenu ;
• on retire le support transfert ;
• si besoin est, on découpe le complexe ainsi obtenu suivant le profil souhaité ;
• on galbe éventuellement le complexe résultant à la forme désirée ;
• on enduit la face libre du polymère expansé d'une couche de couverture en une résine apte à produire par polymérisation un polymère compact ;
• on rend solidaire de la face externe de la couche de couverture ainsi obtenue une feuille souple d'un matériau décoratif de la forme et de la dimension désirées, qui déborde au moins en partie de la couche de couverture ;
• on provoque la polymérisation de cette couche de couverture ;
• on découpe de façon appropriée la partie débordante de la feuille externe souple de recouvrement et l'on rabat latéralement cette partie débordante contre le support de siège ;
• on rend la partie débordante rabattue solidaire du support de siège.

To this end, the subject of the invention is a method of manufacturing and fixing a lining on a seat support, characterized by the following successive phases:

• a layer of resin mixed with a blowing agent is deposited on a transfer support;
• we partially drown the layer of springs in this layer,
• polymerization and at least partial expansion of the resin are caused by allowing the springs of the layer of expanded polymer thus obtained to protrude;
• the transfer support is removed;
• if necessary, the complex thus obtained is cut according to the desired profile;
• optionally shaping the resulting complex to the desired shape;
• the free face of the expanded polymer is coated with a covering layer in a resin capable of producing a compact polymer by polymerization;
• is made integral with the outer face of the covering layer thus obtained a flexible sheet of a decorative material of the desired shape and size, which extends at least in part from the covering layer;
• this cover layer is polymerized;
• the protruding part of the flexible outer covering sheet is cut appropriately and this protruding part is folded laterally against the seat support;
• the folded overhanging part is made integral with the seat support.

The material constituting the flexible outer sheet may be fabric, plastic, leather, velvet and, more generally, any flexible decorative material used to cover seats.

The upholstery according to the invention can be fixed in a particularly simple manner on a seat frame, after having cut the projecting part of the flexible external covering sheet appropriately and laterally folded this part over the seat frame, in particular by gluing or stapling of the folded part on the seat support.

It is clear that such a method is advantageously distinguished by its simplicity and its ease of implementation of the methods of the prior art mentioned above.

The lining fixed in accordance with the invention lends itself to an excellent finishing of the lining, with perfect continuity of the flexible covering sheet.

It is certainly known, from US-A-2,076,619, a cushion for a chair, which comprises a rigid lower plate, a padding material such as cotton, and an outer sheet which covers the padding material and which is folded over- below the rigid plate, of which protruding parts are engaged in cutouts of the edges of the outer sheet and then folded down to make these edges integral with the underside of the plate. The external sheet does not, however, adhere to the padding material, nor, a fortiori, to a vandal-resistant lining, and the cushion thus produced is made integral with the seat part of the chair by means completely independent of this external sheet. .

According to the invention, which aims at the use of a seat cover in which a flexible external sheet adheres to the cover and serves as a means of attachment to the seat itself, the manufacture of the cover is divided into several phases.

We first make the vandal resistant part, which includes the metal sheet, the layer expanded and possibly the compact layer. This set once made will be cut to the desired shape.

Notches can be made locally to allow, after a possible bonding, to realize curved, concave or convex shapes.

Then on this element already produced, a flexible outer sheet of decorative material is reported. This last sheet will be of dimensions greater than that of the sheet previously cut and possibly formed, in order to obtain at the necessary places a free edge which makes it possible to fix, in whole or in part of its periphery, the complex thus obtained on its support. The connection between the flexible outer sheet of decorative material and the previously cut web can be done either by coating as in the previous case, or by application of the connecting material by means of a projection (for example with a spray gun) or a mechanical deposit.

The polymerization of the different layers can be done either all at once or in several stages. It can be carried out for each of the components by heating or by adding a catalyst.

The phases of the above process can be carried out in a discontinuous sequence. We can deliver to users the assembly consisting of the sheet of helical springs partially embedded in the expanded polymer, the finishing operations that constitute the application of the compact polymer and the flexible sheet of decorative material being carried out subsequently according to the preceding description.

• la figure 1 est une vue en perspective d'une garniture utilisée dans le cadre de l'invention ;
• les figures 2 et 3 sont des coupes transversales illustrant la fabrication de cette garniture ;
• La figure 4 illustre une découpe particulière de la feuille souple externe de la garniture ;
• La figure 5 illustre la garniture réalisée avec la feuille souple de la figure 4.

The accompanying drawings, which are not limiting, illustrate the invention. In these drawings:

• Figure 1 is a perspective view of a packing used in the context of the invention;
• Figures 2 and 3 are cross sections illustrating the manufacture of this lining;
• FIG. 4 illustrates a particular cutout of the external flexible sheet of the lining;
• Figure 5 illustrates the packing made with the flexible sheet of figure 4.

As can be seen in FIG. 1, the lining comprises, in a manner known per se, a layer 1 of expanded plastic material, in which are partially embedded helical springs 2 interleaved.

A layer 3 of a compact polymer is integral with the face of the layer 1 of expanded plastic opposite to that by which the springs 2 protrude.

To the external face of this layer 3 adheres a flexible sheet 4 of a covering material, which extends laterally from the layer 3 of a length sufficient to allow the fixing of the lining on an appropriate seat support, by gluing or stapling on this support of the protruding parts, after elimination by cutting of the corner parts such as 5 or others and folding of the side parts 6.

It is clear that this method of fixing the lining on a seat frame or on another support is much simpler than the operations previously proposed in the art for fixing a lining of the same general type on a support frame. It is also clear that it is possible to precisely connect edge to edge the folded-down portions 6 and to obtain a quality of finish of the lining which the previous methods made it difficult to achieve.

Finally, due to the fixing of the sheet 4 on a compact surface and the tension exerted on this sheet by the folded parts 6 glued against the seat support, there is no risk of the sheet 4 creasing, which allows to use, as constituent materials of this covering sheet, products as different as fabrics, plastics, leather or others.

The layer 1 of expanded plastic may, in known manner, consist of a polyvinyl chloride foam, silicone, polyethylene or similar materials.

Layer 3 of compact polymer may also be made of polyvinyl chloride, polyethylene or silicone, or similar materials.

Figures 2 and 3 show how a packing according to the invention can be produced in a simple manner.

In a first step (FIG. 2), a layer of a mixture of a liquid monomer, a blowing agent and a layer of a non-adherent support, such as transfer paper, is deposited on a sheet 8. a polymerization catalyst, the layer of helical springs 2 is partially drowned in this layer so that the springs emerge from the layer 1 thus deposited, and polymerization and expansion of the polymer are brought about.

The sheet 8 is then removed from the assembly thus produced and, on the face of the layer 1 opposite the springs 2, a layer of a monomer and of a polymerization catalyst is applied and this is caused to polymerize. monomer to obtain layer 3 of the compact polymer adhering to layer 1 of expanded plastic.

It then suffices to glue the flexible sheet 4 of covering on the external face of the layer 3, causing it to extend laterally, and optionally to calendering the assembly thus obtained and to vulcanizing the polymers, to obtain the compliant lining. to the invention.

It will be noted that this process makes it possible to perfectly curve the filling to the desired shapes, concave or convex, before the installation of the flexible external sheet 4 of covering. To facilitate this shaping, notches can be made in appropriate locations on the anti-vandalism support on which the sheet 4 is applied.

To set up the lining thus produced on a seat, the flexible external sheet 4 (fabric or other) will advantageously be cut as shown in FIG. 4, that is to say by cutting and eliminating at right angles the corner part of this sheet and in providing a rounded notch 10 in the part applied to the anti-vandalism support and corresponding to the rounded part of the latter (see FIG. 1).

As can be seen in FIG. 5, after having laterally folded down the lateral parts 6 of the sheet 4 which project beyond the support, it is then possible to sew edge to edge the contiguous parts to erase the cutouts previously provided and give the assembly an appearance pleasing to the eye.

Claims (1)

1. A method of manufacturing cushioning and fastening it to a seat base, characterised by the following successive steps:

   - a layer (1) of resin mixed with a blowing agent is deposited on a transfer backing (8);

   - the sheet of springs (2) is partially immersed in this layer;

   - the polymerisation and at least partial expansion of the resin are effected, the springs (2) being allowed to project from the layer (1) of expanded polymer thus obtained;

   - the transfer backing (8) is removed;

   - if need be, the composite material thus obtained is cut along the desired outline;

   - the resultant composite material is shaped to the desired form;

   - the free face of the expanded polymer is coated with a protective layer (3) of a resin capable of producing a compact polymer by polymerisation;

   - a flexible sheet (4) of decorative material of the desired shape and size, projecting at least partly beyond the protective layer (3), is firmly connected to the outer face of said protective layer;

   - polymerisation of this protective layer (3) is effected;

   - the projecting portion of the flexible outer covering sheet (4) is cut appropriately and said projecting portion is folded down at the sides against the seat base;

   - the folded projecting portion is firmly connected to the seat base.

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