FR2883790A1 - Manufacturing process for padded article such as vehicle seat component uses rigid backing panel with turned-over edges to press in lips of supple covering material - Google Patents

Abstract

The process, in which a layer of a supple covering material (5) is inserted in a mould which is then filled with an expanding polymer foam before a rigid backing panel (2) attached to a mould cover (8) is fitted in place, has the backing panel made with turned-over edges (12) that press against projecting lips (11) on the edges of the covering layer to create a sealed joint as the foam is expanded to fill the mould cavity and polymerised. In a variant of the process a layer of a thermal adhesive film can be applied to the supple covering material lip so that it melts from the heat of the foam polymerising reaction to give added adhesion to the joint.

Description

Method of manufacturing a stuffed object

  padded which can be manufactured by this method.

  The present invention relates to a method of manufacturing a stuffed object, such as a seat element of a motor vehicle, and a padded object capable of being manufactured by this method.

  More particularly, the invention relates to a method of manufacturing a stuffed object comprising a foam body covered at least by a rigid bottom and a flexible cap, the cap having a peripheral edge along the bottom, said method comprising the following successive steps .

  (i) introducing the cap into a tub belonging to a mold, said cap forming a lip at said peripheral edge, (ii) injecting foam into the cap, (iii) closing the mold by placing a lid prior to complete expansion of the foam, the lid having an inner face which carries the bottom, (iv) expansion and polymerization of the foam, to form the foam body.

  The document FR-A-2 572 016 describes such a manufacturing method, which has the particular disadvantage that foam is likely to leak at the junction between the bottom and the cap during molding, which can deteriorate the appearance outside the cap and discard the padded object.

  The present invention is intended to overcome this disadvantage.

  For this purpose, according to the invention, a manufacturing method of the kind in question is characterized in that the rigid bottom has a peripheral fallen edge at said peripheral edge of the cap, and in that during the step (iii), the dropped edge of the bottom flaps said lip towards the inside of the mold and remains in lateral contact with a face of said lip after placement of the lid.

  Thanks to these arrangements, the dropped edge and the lip cooperate to form a leaktight seal to the foam during polymerization, over the entire surface of their contact. The junction is found inside the foam, so that the expansion of the foam on both sides of the junction reinforces this junction by pressing the lip against the rim. The fact that the junction is internal also confers a perfect aesthetic finish.

  In various embodiments of the process according to the invention, one or more of the following provisions may also be used: at least one heat-sealing film is interposed between the lip and the flanged edge before step (iii), and during step (iv), the fusible film is melted by sticking on the lip and the dropped edge; during step (iv), the heat-sealing film is melted under the effect of the heat released by the polymerization reaction of the foam; the lip extends beyond the dropped edge after closing the mold in step (iii), the end portion of said lip being folded substantially 180 degrees against the inner face of the edge fell under the effect of the expansion of the foam during step (iv); during step (iii), the lip is slightly inclined at an angle towards the fallen edge: the foam adheres to the bottom during phase (iv); - The cap is held in place at the periphery of the opening of the tank by a retaining means; - The retaining means is selected from a suction system and self-gripping loops; a fold line delimits the lip.

  Furthermore, the subject of the invention is also a padded article capable of being manufactured by a manufacturing method as defined above, comprising a foam body covered at least by a rigid bottom and a flexible cap, the cap presenting a peripheral lip in contact with the bottom, the foam body conforming to the inner surfaces of the cap and the bottom and adhering to said inner surfaces, characterized in that the rigid bottom has a peripheral fallen edge which has an outer face in lateral contact with one side of the peripheral lip.

  The outer face of the peripheral flanged edge may be glued to the peripheral lip by heat-sealing material.

  The lip can be extended by an end portion folded substantially 180 degrees against the inner face of the fallen edge.

  Other features and advantages of the invention will become apparent from the following description of some of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings.

On the drawings.

  FIG. 1 is a sectional view of a padded object according to the invention; FIG. 2 is a sectional view of a mold allowing the implementation of the method and the production of the padded object of FIG. 1, - 3a to 3d show a sectional view of the mold and padded object respectively during steps (i) to (iv) of the method according to the invention, - Figures 4a, 4b, 4c are 3a, 3c and 3d, respectively - FIGS. 5a and 5b illustrate the use of a fold line on the cap, FIGS. 6a, 6b, 6c show in cutaway view a detail of the formation of FIG. a junction between the cap and the rigid bottom according to a second embodiment, - Figure 7 shows a cutaway view of a variant of the second embodiment, - Figures 8a, 8b, 8c show a cutaway detail of the formation a junction between the cap and the rigid bottom according to a third embodiment.

  In the different figures, the same references designate identical or similar elements.

  Figure 1 shows an example of a padded object 1 according to the invention, including a motor vehicle seat member. It may be for example a seat back, a seat cushion, or possibly an armrest, a headrest or other.

  The padded object 1 has on one of its faces a rigid bottom 2 which may be in the form of a substantially planar piece made of any material (metal, plastic, resin, wood, compressed cardboard, etc.) having a hardness for example, greater than 50 shore.

  This rigid bottom 2 provides a stiffening function of the upholstered object 1. Depending on the use, it also allows the attachment of the upholstered object 1 to a structural element of the seat or the vehicle, or the attachment from an accessory or mechanism to the stuffed object 1.

  At this rigid bottom 2 is assembled a padding 3. This padding comprises a foam body 4 wrapped in a flexible cap 5 which envelops the foam body 4 on all sides of the object 1 other than that occupied by the bottom 2. The cap 5 is made of a material of the type used in automotive upholstery (fabric, leather, imitation leather, etc.).

  The method according to the invention uses a mold 6, 35 shown in FIG. 2, which comprises a tank 7 and a lid 8. The introduction of the lid 8 on the tank 7 forms a closed space which makes it possible to limit the expansion foam during polymerization while giving it the desired shape. Advantageously at the opening of the tooling 6, the vessel 7 has a profile 17 complementary to the profile 18 of the lid in order to ensure the seal and to support the lid 8. The tank 7 can be made in several parts and comprise for example a removable frame 19 surrounding the cover 8, in particular to facilitate demolding. The frame 19 also facilitates the introduction of the cap 5 in the tank during the first step of the manufacturing process, as explained below.

  This process is illustrated in FIGS. 3a to 3d and 4a to 4c, which show the four successive steps of the process: (i) introduction of the cap 5 into the tank 7, (ii) injection of foam into the cap 5, (iii) ) closure of the mold 6 by placing the cover 8 before complete expansion of the foam, (iv) expansion and polymerization of the foam, to form the foam body 4.

  FIGS. 3a and 4a illustrate step (i), during which the cap 5 is introduced into the tank 7 of the mold 6. The flexibility of the textile material of the cap 5, if necessary preformed, allows a set-up marrying the inner wall of the vessel 7, including the lower surface of the frame 19 at a return 20 of the cap.

  The cap 5 has an opening opposite the cover 8, which opening is delimited by a peripheral edge of said cap. This peripheral edge forms a peripheral annular lip 11 which, before closure of the cover 8, can extend horizontally in the extension of the return 20 as in the example shown. The lip 11 forms an annular band of width L for example between 5 and 10 mm which protrudes towards the inside of the opening of the vessel 7. The cap is held in place in the tank 7 by any known means of retention ( suction, hook-and-loop or other loops) - not shown.

  FIG. 3b illustrates step (ii), during which a given quantity of foam 10, for example polyurethane foam, is injected into the interior space delimited by the cap 5. The quantity of foam 10 is determined by depending on the final volume and the desired density for the foam body 4. Upon injection of the foam 10, the polymerization and expansion reaction of the foam is initiated. The complete expansion of the foam requires a few seconds to a few minutes. This time is used to achieve the next step (iii).

  Figures 3c and 4b illustrate step (iii), wherein the mold 6 is closed by the introduction of the cover 8 in the opening of the tank 7, before the complete expansion of the foam 10. The door cover on its inner face the rigid bottom 2, fixed by any known means (suction, self-gripping loops, magnetization for ferrous material bottom, or other). The introduction of the rigid bottom 2 on the cover 8 is advantageously carried out before the injection of the foam 10 during step (ii).

  The rigid bottom 2 has on its periphery a particular conformation forming a dropped edge 12, which extends towards the inside of the mold 6.

  When placing the lid 8 during step (iii), the dropped edge 12 comes into contact with the lip 11 by folding it towards the inside of the mold 6. The outer surface of the fallen edge 12 remains in lateral contact with the lateral face of the lip 11 which is oriented towards the bottom 2 (see Figure 4b).

  Advantageously, the lip 11 is slightly inclined obliquely towards the dropped edge 12 and downwards, which then facilitates the sealing between the lip and the dropped edge, and the plating of said lip against the dropped edge, as explained below. after.

  The dropped edge 12 may be integral with the rigid bottom 2 or constituted by an insert on this bottom. This fallen edge 12 may have with the rigid bottom 2 an angle close to 90 and may eventually end in a rounded.

  FIGS. 3d and 4c illustrate step (iv), during which the foam 10 expands by polymerizing, after closure of the mold 6. The mold 6 limits this expansion and causes the foam to occupy all the space. space thus delimited. During this expansion, the pressure of the foam 10 accentuates the support of the lip 11 against the dropped edge 12, thereby reinforcing the cohesion of the junction between the cap and the bottom by applying the radially inner face of the lip 11 against the outer face of the fallen edge.

  The solidification of the foam 10 is then freeze this junction after cooling of the foam. The padded article 1 is then finished and can be demolded by opening the mold 6. After demolding, the junction between the bottom 2 and the cap 5 has a finish of optimal aesthetic quality. No subsequent finishing operation is necessary.

  FIGS. 5a and 5b illustrate a variant of the invention in which a fold line 13 is formed in the cap 5 at the opening of the tank 7, delimiting the lip 11, substantially to the right of the fallen edge 12.

  This fold line 13 is made by any known means allowing a local reduction of the thickness of the cap 5, for example a material removal, a seam, a cold stamping, a hot or melt forming, or other.

  The fold line 13 has the effect of facilitating the folding of the lip 11 during the application of the fallen edge 12 by forming a preferred pre-positioned folding zone (Figure 5b).

  Figures 6a, 6b, 6c show the detail of the embodiment of the junction between the lip 11 of the cap 5 and the fallen edge 12 of the rigid bottom 2 according to a second embodiment. According to this embodiment, a heat-sealing film 14 is advantageously disposed between the lip 11 and the dropped edge 12. This heat-sealing film 14 may be put in place prior to step (iii).

  The fusible film 14 may be placed on the surface of the lip 11 facing the fallen edge 12 as in the example shown, or on the surface of the fallen edge 12 facing the lip 11. The fusible film is secured to the lip 11 or the fallen edge 12 by any known means, for example by sewing or gluing. As shown in FIG. 6a, the film 14 may for example be fixed to the lip 11 by a seam line 13 which forms a fold line between the lip 11 and the remainder of the cap 5.

  Thus, when the cover 8 and the dropped edge 12 are put in place, the heat-sealing film 14 is interposed between the lip 11 and the dropped edge 12 (FIG. 6b).

  As the expansion of the foam 10, shown in FIG. 6c, is an exothermic reaction, the heat produced by this reaction is transmitted to the lip 11 as well as to the dropped edge 12. This results in a melting of the heat-sealing film 14 which ensures the seal between the lip 11 and the bottom 2. After cooling, this melting produces a bonding of the lip 11 and the flanged edge 12. This bond strengthens the junction between the lip 11 of the cap 5 and the flange 12 rigid bottom 2.

  FIG. 7 shows a variant of the second embodiment, in which the heat-sealing film 14 is extended at the junction surface 17 between the cover 8 and the tank 7. This heat-sealing film is used to position the cap and to hold the tongue 11 in position in the tooling.

  Figures 8a, 8b, 8c show the detail of the embodiment of the junction between the lip 11 of the cap 5 and the fallen edge 12 of the rigid bottom 2 according to a third embodiment. Figure 8a shows the detail before the closing step (iii) of the cover 8. The lip 11 forms a ring band much wider than in the previous embodiments.

  Figure 8b illustrates the placement of the cover 8. The dropped edge 12 folds the lip 11 towards the inside of the mold as indicated above, but this lip protrudes from the dropped edge 12 downwards. The lip 11 is advantageously inclined towards the fallen edge 12 and downwards.

  FIG. 8c illustrates the result after the expansion of the foam 10: the foam 10 acts on the end portion of the lip 11 which protrudes and causes a new deformation which folds this end portion substantially 180 degrees against the internal face of the edge 12. Such folding, prior to curing of the foam, provides improved sealability to foam leakage. This conformation, after curing of the foam 10 is stiffened. The lip 11 thus forms a real hook around the fallen edge 12, which contributes to reinforcing the junction between the lip 11 of the cap 5 and the fallen edge 12 of the rigid bottom 2.

  Of course, it is possible to combine the second embodiment (gluing) with the third embodiment (lip folded).

  In all embodiments, the polyurethane foam during its expansion comes into contact and perfectly matches the rigid bottom 2 and the cap 5, preferably by sticking against the inner face of the bottom 2 lo and the cap. For this purpose, a material compatible with this bonding (for example metal, plastic, resin, wood, compressed cardboard or any other material adhering to the foam 10) is selected for the bottom 2 and / or a physico-chemical preparation of the inner surface of the bottom 2 to change the surface condition so as to increase the adhesion of the bonding.

Claims (12)

  A method of manufacturing a stuffed object (1) comprising a foam body (4) covered at least by a rigid bottom (2) and a flexible cap (5), the cap having a peripheral edge along the bottom, said method comprising the following successive steps: (i) introducing the cap (5) into a tank (7) belonging to a mold (6), said cap (5) forming a lip (11) at said peripheral edge, (ii) ) injecting foam (10) into the cap (5), (iii) closing the mold (6) by placing a lid (8) before the foam (10) is completely expanded, the lid (8) ) having an inner surface which carries the bottom (2), (iv) expansion and polymerization of the foam (10), to form the foam body (4), characterized in that the rigid bottom (2) has an edge dropped (12) peripheral at said peripheral edge of the cap, and in that during step (iii), the flanged edge (12) of the bottom flap said lip (11) worm s inside the mold and remains in lateral contact with a face of said lip (11) after placing the cover (8).   2. Method according to claim 1, wherein at least one heat-sealing film (14) is interposed between the lip (11) and the dropped edge (12) before step (iii), and during step (iv). ), the fusible film is melted by sticking on the lip (11) and the dropped edge (12).   3. Method according to claim 2, wherein, during step (iv), the heat-sealing film is melted under the effect of the heat released by the polymerization reaction of the foam.   4. A method according to any one of the preceding claims, wherein the lip (11) extends beyond the dropped edge (12) after closing the mold (6) in step (iii), the end portion of said lip (11) being folded substantially 180 degrees against the inner face of the fallen edge (12) under the effect of the expansion of the foam in step (iv).   5. Method according to any one of the preceding claims, wherein, in step (iii), the lip (11) is slightly inclined obliquely towards the fallen edge (12).   The method of any of the preceding claims, wherein the foam (10) adheres to the bottom (2) during phase (iv).   7. Method according to any one of the preceding claims, wherein the cap (5) is held in place at the periphery of the opening of the vessel (7) by a retaining means.   8. The method of claim 7, wherein the retaining means is selected from a suction system and hook-and-loop fasteners.   9. Method according to any one of the preceding claims, wherein a fold line (13) delimits the lip (11).   10. A padded article (1) that can be manufactured by a manufacturing method according to any one of the preceding claims, comprising a foam body (4) covered at least by a rigid bottom (2) and a flexible cap (5). ), the cap having a peripheral lip (11) in contact with the bottom, the foam body (4) conforming to the inner surfaces of the cap (5) and the bottom (2) and adhered to said inner surfaces, characterized in that the rigid bottom (2) has a peripheral flanged edge (12) which has an outer face in lateral contact with a face of the peripheral lip (11).   Padded article according to claim 10, wherein the outer face of the peripheral flanged edge (12) is adhered to the peripheral lip (11) by a fusible material.   12. Padded article according to any one of claims 10 and 11, wherein the lip (11) is extended by an end portion folded substantially 180 degrees against the inner face of the flange (12).