FR2558147A1 - Top of industrial seat and method of manufacture thereof - Google Patents

Abstract

SEAT IN THE FORM COMPRISING A BODY OF FOAM 1 OBTAINED BY CUTTING AND A COVERING FIXED BY A HOT MELT FILM. THE MANUFACTURING PROCESS CONSISTING OF REALIZING THE INTERNAL BODY 1 BY CUTTING BY DEFORMATION, COATING THE COATING 11 OF A THERMOFUSIBLE FILM 12 AND POSITIONING IT ON A MOLD 7, THEN AFTER HEATING THE FILM 12 PRESSING THE BODY 1 ON THE COATING 11 CONTENT BY MOLD 7.

Description

 The present invention relates to the manufacture of shaped industrial seat tops comprising an internal body of plastic foam of the chosen shape, provided with a covering, for example of fabric.

 The currently most widespread technique for this manufacture of shaped seats consists in molding the body of plastic foam in the fabric ("in situ" molding).

 To this end, the fabric is first made waterproof by an appropriate coating, then it is shaped by depression in a shell of a mold.

The plastic material (such as polyurethane) is injected snuite in the liquid phase then the mold is closed and the foam-generating expansion occurs in a closed mold. This expansion repels and maintains the fabric in the shapes given by the mold.

 This process has many drawbacks and in particular - the only foams that can be used are these so-called "cold" foams: these foams have mechanical characteristics inferior to those cast in blocks and subsequently cut, - the contact skin between foam and coating is relatively thick and not very flexible, due to the necessary sealing layer as well as the densification of the foam in contact with the coating, - the process is heavy in investments. It entails significant storage of coatings if it is to ensure rapid supply of the finished complex in response to demand.

 The subject of the invention is a method making it possible to avoid these drawbacks and to produce top quality shaped seat covers under industrially more favorable conditions.

 The method according to the invention consists in - separately manufacturing the foam body in the desired shape by cutting by deformation from foam in block, - in placing the coating provided with a good film of hot-melt plastic material on a mold with the shape corresponding, - to heat the hot-melt film up to, or beyond its melting point, - to enclose between the plates of a press the foam body and the mold thus coated, - to cool the hot-melt film to to its solidification.

 The invention relates, as new industrial products, to the seat covers made up of a foam body shaped by cutting to which a covering such as a fabric, a nonwoven fabric, etc. is fixed by hot-melt film.

For practicing the invention, the following arrangements will preferably be used
a) The coating provided with its hot-melt film, by superposition or pre-coating, is positioned on the mold, in the press, by means of a support frame which is then used to extract the finished product from the press.

 b) The heating is carried out by a mobile radiant panel which moves between the plates of the press when it is in the open position and whose radiant elements are oriented towards the coating and the hot-melt film.

 c) The mold includes air suction channels for shaping the cooling, a circulation of cooling fluid.

 d) The foam body cut by deformation is positioned on one of the press plates by vacuum or mechanical grip.

The invention is more fully described below with reference to the accompanying drawing in which
Figure 1 illustrates in schematic section the cutting of the foam body by deformation.

 Figure 2 is a schematic view in vertical section of the entire press during the process.

 FIG. 3 is a schematic perspective view of the seat top of FIGS. 1 and 2.

 Referring to these figures, it can be seen that for the production of a seat top according to FIG. 2, a foam body 1 is first produced by cutting by deformation to the desired shape. The cutting by deformation (FIG. 1) consists in compressing (arrows F) the body 1 against a surface 4 having openings at the locations of the drawings to be hollowed out 2, 3 (FIGS. 2 and 3) and to level the foam which overflows in S through said openings, for example by means of knives 6. Once the compression F is released, the block takes the desired shape, shown in FIGS. 2 and 3.

 A mold 7 having the opposite shape to that of block 1 is also produced: it has reliefs 8 corresponding to the recesses 2, 3, of block 1. This mold is preferably provided with air intake channels 9 and d a circulation 10 for a cooling fluid such as water.

 On the covering 11, for example in fabric or textile, etc., a hot-melt film 12 is placed, by superposition or coating, and said covering 11 is positioned on the mold 7 by any means and preferably by means of a frame. mobile 13. The mold 7 is positioned on one of the plates 14 of a press, while the block 1 is positioned on the other plate 15.

 The heating film 12 is then heated to its melting point.

 In the example shown, this heating is achieved by means of a radiant panel 16 movable between the plates of the press between a position where the radiant elements 17 face the coating 11, 12 and a withdrawal position allowing the closure of the hurry.

 Several frames 13 can be provided so as to be placed in sequence between the plates 14 and 15, one frame being in the process of filling while another is in the heating and pressing position.

The procedure is as follows
The lower plate 14 is provided with the mold 7 which can be placed at a fixed station; the frame 13 lined with the fabric 11 and the film 12 is positioned on the mold 7, while the block 1 previously cut by deformation is positioned on the plate 15, for example by the depression 19. The fabric 11 and the film 12 are curved by vacuum through the channels 9 communicating with the vacuum space 18. The radiant panel 16-17 is introduced between the plates 14 and 15 and the heating is carried out to the melting point of the film 12. Then the panel 16- 17 is removed and the plate 14 lowers and compresses the block
1 against the set 12-11-7. The circulation of water 10 then cools the mold 7 until the film 12 freezes and consequently sticks the fabric 11 on the block 1. The press is then opened and the coated block 1 is extracted with the frame 13.A new cycle can then be started by introducing another frame 13 and another block 1.

 The heating time, the temperature, the cooling time will be adapted to the nature of the hot-melt plastic film used.

 The products obtained by the means of the invention are formed, due to the process, of an internal body 1 obtained by cutting and therefore devoid of molding skin, on which a coating 11 is bonded by hot-melt film 12. The lateral edges of the seat can be produced by folding down the sides of the covering and fixing them, for example by stapling or gluing, on a rigid bottom or even on the opposite face of the foam body 1.

 Such seat covers have qualities much superior to those obtained previously due to the use of cut foams whose flexibility is much greater than that of foams molded to the piece as well as due to the absence of molding skin and waterproofing layer. It is therefore possible to obtain cushions which are both shaped and very flexible.

 In addition, the fact of not using the plastic material of the foam in the liquid phase avoids any risk of soiling and presents a total healthiness for the personnel.

 The necessary tools are much less expensive, which makes this technique accessible to smaller series. On the other hand, the manufacturing can thus be separated into a manufacturing of blocks which requires heavy investments as well as a centralized manufacturing, and a manufacturing by cutting and assembly likely to be carried out in small local workshops. This flexibility allows customers to be served faster while reducing the storage of covering fabrics.

 Different variants can be adopted for carrying out the method of the invention. Thus, for example, the positioning of the body 1 on the plate 15 can be achieved by mechanical means, that the fabric 11 and its film 12 can be positioned manually, that the heating can be carried out tza- towards the mold 7.

 However, heating by radiant panel which can be moved between the molds is a preferred arrangement because it makes it possible to use coatings of any kind, even those sensitive to heat.

Claims (6)

 1. A method of making shaped industrial seat tops comprising a shaped internal plastic foam body, provided with a covering, for example of fabric, characterized in that the internal foam body (1) is produced in the desired shape by cutting by deformation from block foam, the covering (11) is provided with a hot-melt film (12) and placed on a mold (7) having the shape corresponding to the body (1), the film (12) is heated up to, or beyond, its melting point, the foam body (1) is press-tightened on the coating (11) and the molten film (12) thus retained by the mold (7) and the film (12) is then cooled.  2. Method according to claim 1, characterized in that the coating (11) provided with the film (12) by superposition or pre-coating, is positioned on the mold (7), in the press (14, 15) by the means a movable support frame (13) which is then used to extract the finished product from the press.  3. Method according to any one of the preceding claims, characterized in that the heating is carried out by a mobile radiant panel (16, 17) which moves between the plates of the press and whose radiant elements (17) are oriented towards the mold (7)  4. Method according to any one of the preceding claims, characterized in that the mold (7) comprises air suction channels (9) for shaping the fabric (11) as well as, optionally, a circulation coolant (10).  5. Method according to any one of the preceding claims, characterized in that the body (1) cut by deformation is positioned on one of the plates of the vacuum press.  6. shaped seat top comprising a foam body (1) provided with a covering (11), characterized in that the foam body (1) is obtained by cutting and the covering (11) is fixed by hot-melt film (12).