GB2056909A - Method and apparatus for use in producing a material in the form of a padded sheet - Google Patents

Abstract

The present specification describes and claims a method and apparatus for producing a material in the form of a padded sheet, from a number of superposed layers of synthetic material. The layers basically comprise a cover sheet and a base sheet made of a material having elastic cells which are capable of being compressed. In this material, the elastic cells of the base sheet are crushed locally according to the outline of the required design for the quilting and padding and the crushed cells are blocked permanently, at least on a portion of the thickness of the base sheet. In the apparatus, the heat is applied by a plate which contacts the underneath surface of the material, a moulding tool contacting the upper surface and the internal being compressed between the heated plate and the moulding tool to provide heat welding only at the internal compressed regions determined by the tool design.

Description

SPECIFICATION Method and apparatus for use in producing a material in the form of a padded sheet The present invention relates to a method of producing a material in the form of a padded sheet and a machine for forming such sheets.

In particular the present invention relates to a method and apparatus for producing products, in the form of sheets or films, comprising a plurality of sheets some of which at least are made of heat-weldable synthetic material, to obtain in particular quilted sheets.

Various types of padded covering materials are already known for armchairs, armchair and car seat covers, furniture fabrics, wall hangings, etc.

In order to heat-weld a plurality of sheets one onto the other, presses are used which have to exert significant pressures. Known heating presses have plates controlled by power jacks which effect a significant travel.

However, such jacks are not only very expensive, but, moreover, they operate relatively slowly and they require a powerful hydraulic plant.

In certain cases, it is possible to use highfrequency welding presses which are lighter in weight. However, high-frequency heat-welding connot be applied to all synthetic materials.

The object of the present invention is to provide a method and apparatus for producing a padded and quilted material of the above type which is suitable for mass-production and is inexpensive, without this being detrimental to the qualtity of the padding and the quilting nor to the products obtained for effecting the method.

According to the present invention there is provided a method of producing a padded and quilted product formed from a cover sheet and a base sheet made of a material having elastic cells which are capable of being compressed, in which the cells are crushed locally according to the outline of the required design for the quilting and the padding to be achieved and the cells in the crushed state are blocked permanently, at least on a portion of the thickness of the base sheet.

According to a further aspect of the present invention there is provided a machine for the shaping and the heat-welding of a complex having a plurality of layers, the machine comprising two plates, one of which at least is adapted to be heated, and which can be used to compress and heat weld the complex, a first plate of said two plates, being arranged to effect an opening and closing movement to enable a complex to be located between the plates, and a second plate being arranged to effect a shorter opening and closing movement to compress a complex located between said plates, displacement members being provided to control the movement of the first plate, these displacement members being double arms which form a toggle articulation, one end being connected to the first plate, the other to a frame of the machine, the articulated joint between the arms of each member, being connected to a control jack, compression members in the form of power jacks, being arranged to control the closure movement of the second plate, the second plate carrying forming tools and being movable between one working position opposite the first plate for the compression operation of the machine, and a disengaged position relative to the first plate, this second plate being provided with translation means which are capable of being retracted when the plate is in the working position opposite the first plate, to occupy a floating position and follow the approach and compression movement of the two plates.

As one of the plates effects a significant travel to close the gap between the plates, this gap being necessary for the introduction and extraction of the products, and as the other plate effects the compression travel, power jacks are avoided which have to have a long travel. This enables not only the cost of the plant to be reduced in particular, but also the time of the working cycle to be reduced and, consequently, the output of the machine to be increased.

Preferably suction means are connected to cavities between blades of the tool to provide a reduced pressure therebetween. This presents numerous advantages because, whilst permitting the evacuation of noxious or dangerous gases emitted during heat-welding, the sheets of the complex are deformed prior to heat-welding. A product is thus obtained having an asymmetric structure corresponding to a conventional quilted sheet which would be cut along its median plane. In fact, owing to the deformation of the sheets prior to their heat-welding being effected at least at the level of the "stitches" of the quilting, the rear surface of the product remains planar i.e. the quilting does not tend to protrude from the rear side. This permits a significant saving in the filler material of the quilting.

Another advantage of the reduced pressure lies in opening the tool, the product remaining on the plate carrying the tool and being separated from the other smooth heated plate.

The above described construction wherein, on the one hand, the plate carrying the tool may return to and leave the machine and, on the other hand, the smooth plate is heated, present in particular the following advantages: ~the tools can be changed easily; in addition, they are simply placed upon the said second plate. The tool placed upon the plate may comprise a plurality of distinct parts.

~the positioning of the sheets is simple.

~because of their weight, the sheets tend to sink into the cavities of the mould and to take the quilting form whilst acting in the same direction as the suction.

the hottest surface during the heat-welding is the rear surface of the manufactured product. This enables more fragile sheets to be used for the front face, i.e. the visible face.

-it is easier and less expensive to provide the smooth place with an anti-adherent layer than to do this on the tools, especially as the tools are numerous in dependence upon the decorative patterns to be achieved, etc.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic section through one embodiment of a product according to the present invention formed from two layers before the quilting is effected; Figure 2 shows the layer of Fig. 1 after compression and heat-sealing; Figure 3 is a section through a second embodiment of a product according to the invention; Figure 4 is a schematic section through the various layers constituting another embodiment according to the invention, before these various layers are partially made integral; Figure 5 is a section through one embodiment of a machine according to the invention; Figure 6 is a section through one detail of the machine shown in Fig. 5;; Figure 7 is a layout diagram of the machine and the supply and discharge devices, for a discontinuous operation, and Figure 8 is a layout diagram of the machine and the supply devices for a continuous operation.

According to Figs. 1 and 2, the simplest embodiment of the invention comprises a cover sheet A and a cell containing base sheet B (Fig. 1). The two sheets A and B are compressed and glued (Fig. 2) to give the surface a padded and quilted effect, leaving an outline T according to the chosen design, i.e. a line, dots, a small surface, etc.

Compression is effected according to the outline T in order to crush permanently with sealing the crushed cells C, the other surfaces of the sheets A and B being left free, of necessity, without being sealed to provide the swollen effect.

This permanent crushing represents a more or less significant portion of the thickness of the sheet B.

According to Fig. 3, the product is obtained from an assembly formed from a cover sheet and a base sheet B comprising two parts Ba and Bb having identical or different physical and chemical characteristics.

According to Fig. 4, the product comprises a visible cover sheet A, a filler sheet B and a base sheet D. The sheets A and B are separated by a layer E of a heat-sealing material.

The same also applies to the filler sheet B and the base sheet D.

The cover sheet A may also comprise a single layer or the combination of several layers joined together by gluing or lamination.

The external surface of the cover sheet A is preferably a fabric, a non-woven fabric, a vegetable or artificial interwoven material, etc.

according to the desired external appearance.

When this external layer forms part of a combination, for example with three layers constituting the cover sheet, an intermediate layer, for example made of foam and/or a lining, is provided in addition to the external sheet, these three layers being joined together by gluing or by lamination.

In the case of an external sheet made of a light fabric or a material having pores which are not very close together, it is advantageous to glue at least a second layer which ensures a a certain tightness or closes the pores to prevent the heat-sealing material from entering the cover sheet, and the sheet of filler material or the base sheet cannot leak through the pores of the external layer of the cover sheet.

The layer of heat-sealing material between the cover sheet and the sheet of filler material or the base sheet is, preferably, a layer which is permeable to air, thus enabling air to pass from one face to the other of the product.

This layer may be integrated with the foam of the expanded material which covers the inner surface of the external layer when the cover layer comprises a combined product having two layers without a lining. This heat-sealing layer may also comprise the lining of the cover sheet.

The heat-sealing sheet advantageously comprises a sealing film which provides a certain permeability to enable air to pass, such as a heat-sealing film having holes or grooves. If the final product does not have to offer this characteristic of being permeable to air, a non-permeable heat-sealing film may be used.

The layer of filler material is, preferably, a sheet of natural fibres, such as cotton and wool, artificial fibres, such as viscose, or synthetic fibres, such as acrylic resin polyester fibres, nylon, etc.

The purpose of the material of the base layer D is essentially for support and firmness in order to give the assembly the necessary mechanical resistance.

It is advantageous to obtain this base sheet D D in the form of a layer of synthetic foam. In the particular chosen example, this foam, having more or less open pores, is impregnated with particles of heat-sealing material. This impregnation may also be replaced by a heatsealing layer disposed between the sheets B and D, as for the heat-sealing layer between the sheets A and B.

The particles impregnating the foam sheet D are chosen in dependence upon the heatsealing temperature which, itself, depends upon the materials A, B, D and E.

In order to have the product the most resistant and the least sensitive to external agents, it is appropriate to choose the highest possible heat-sealing temperature. However, this temperature may be limited by the choice of the materials, such as the materials of the layers A and B which define the appearance of the product and the wear-resistant characteristics, etc. Depending upon these materials, the heat-sealing materials for the layer E and the immersed heat-sealing particles F are chosen so that the heat-seal is formed at the highest possible temperature.

The heat-sealing material is a thermoplastic material or a thermohardenable material, such as nylon, ethyl-vinyl acetate, acrylovinyl resins, etc. or mixtures of these products and polyethylene such as alkathene.

In addition to its supporting function, the sheet D also gives the product a certain elasticity, in combination with the elasticity of the filler material B.

Finally, this sheet D may complete the characteristics of sound insulaton ensured by the sheets A and B, especially in the case of a sheet B being composed of several layers.

The products according to the invention have numerous applications in the field of covering seats, the manufacture of covers for car seats and bench-seats, covering products for furniture, as wall hanging, etc.

By way of example, it is particularly advantageous to use the product according to the invention for the manufacture of footwear, especially fancy footwear such as boots as, for example, apres-ski boots. In this case, since the boot must be watertight, during the manufacture of the product forming the leg, designs may be provided, such as top-stitching in the block, without its being necessary to top-stitch this synthetic material, as is the case at present because this makes the boot permeable.

According to Fig. 5, the machine for the shaping and the heat-welding of one embodiment of the present invention having a plurality of sheets, comprises a frame 1 carrying a first or upper plate 2 and a second or lower plate 3. These plates 2 and 3 are placed one opposite the other, and, in the gap in between, the stack of several sheets can be located in order to compress and heat-weld them along decorative or functional surfaces or lines.

The upper plate 2 is connected to the frame 1 by displacement members 4 comprising toggle levers 41, 42 which are articulated, on the one hand, to the frame 1 and, on the other hand, to the plate 2. The articulated junction 43 between the two respective levers 41, 42 is also joined to a rod 5 controlled by a jack 6. The movement of the rod 5 in the direction of the arrow A causes the lowering or raising movement of the plate 2 in the direction of the arrow B.

The members 4 forming toggle articulations may pivot between a raising position, in which the two arms 41, 42 define a relatively closed angle, and a lowering position (not shown), in which the rod 5 is sufficiently displaced towards the right, according to the Figure, to bring the two arms 41, 42 into alignment one with the other or even beyond the vertical X-X which passes through the point where the lever 41 is articulated to the frame 1.

Such a vertical positioning or a positioning slightly beyond the vertical X-X is important for the compression phase.

In face, when the plate 2 is completely lowered, the arms 41, 42 are practically aligned one with the other so that the compression force, which acts in the vertical direction and which is transmitted by the arms 41, 42 to the frame 1, is only converted by a very weak, even zero component, in the direction of the rod 5, so that the component reflected on the jack 6 during the compression phase is extremely weak.

If, according to an above-suggested variant, the arms 41, 42 pivot to the right of the vertical passing through the point where the arms 41 are articulated to the frame 1, and if there is an angular lug (not shown) integrated with the articulated joint 43, this lug absorbs the compression stresses, so that no compression stress is then passed on to the jack 6.

The second or lower plate 3 comprises a parallel-epipedal box 31 whose upper surface is provided with perforations 32. This box is connected to an air suction circuit shown schematically by the ventilator 7.

The plate 3 rests on rollers 33 rolling on rails 8 which are integrally connected to the frame 1. On its upper surface, i.e. the surface provided with perforations 32, the box 31 carries a tool 9 used for compression and heat-welding purposes. The tool 9 comprises an assembly of vertical blades 91 which are disposed edgewise and whose outline in the horizontal plane corresponds to the designs to be achieved by heat-welding. The tool 9 thus appears as an open grate placed on the upper surface of the box 31, so as to communicate via the apertures 32 with the inside of the box 31.

The complex of sheets 10 to be heatwelded, is placed above the tool 9. In Fig. 5, the suspended form which the material of the layers of the complex 10 assumes has been shown schematically in the gap between the blades 91 of the moulding tool 9.

The rollers 33, which roll on the horizontal rails 8, enable the plate 3 to be brought with its tool 9 either inside the machine, beneath the location of the upper plate 2 for the compression and heat-welding operations, or outside the machine, allowing the upper surface of the tool 9 to become disengaged for the positioning of the complex 10 or for the complex 10 to be removed, after treatment.

The rollers 33, carried by arms which are controlled by a jack (not shown), are retractable into the heat-welding position so that the plate 3 floats on compression jacks 11.

The compression jacks 11, which act upon the plate 3, are power jacks with a short travel. These jacks are powered by hydroelectric power plant 12.

To facilitate the movement of the plate 3 relative to the jacks 11 and to also prevent compression stresses from being exerted upon the rollers 33 and, consequently, upon the rails 8 when the plate is in the compression position, the rollers 33 are retractable (not shown); the rollers being arranged to rise slightly so that the plate 3 only continues to rest on the jacks 11 during the short-travel compression movement.

Although, in theory, such a measure is not necessary, since the jacks 11 raise the plate 3 when the plate 3 is above them, it is nevertheless advantageous, in practice, to have a relatively significant disengagement between the lower surface of the plate 3 and the upper surface of the jacks 11. However, to have this disengagement, it is necessary for the lower plate 3 to be able also to be raised to disengage it from the jacks 11 after the compression phase, when the upper plate 3 is raised.

The lower surface of the plate 2 is constituted by a layer which is anti-adherent at the working temperatures of the machine, to prevent the sheets of the complex 10 sticking to the machine.

To simplify the structure of the machine, the upper plate 2 carries heating means necessary for the heat-welding process. This solution offers the advantage that the hottest part of the compression plates is the upper plate 2, i.e. the plate which corresponds to the rear face of the products. Another advantage of this solution is that the inner surface of the plate 2 is perfectly smooth, so that the complex 10 which is obtained has an asymmetrical structure, the parts in relief being the ones turned towards the tool 9, i.e. the visible face of the product when the rear face is relatively smooth. This provides a 50% saving of the filler means which ensure the swelling of the complex 10 between the heat-welding lines (expanded synthetic material . .

The machine described in Fig. 5 operates as follows:- After placing a complex of heat-weldable sheets onto the tool 9 of the plate 3 in the disengaged position, the plate is automatically pushed back manually into the inside of the machine, so that it is in the working position under the plate 2.

The machine may then commence its working cycle by retracting the rollers 33 and lowering the upper plate 2, the lower plate 3 being then raised in a controlled manner to compress the complex. During the course of this compression phase, the upper plate 2 remains motionless, the compression stresses being essentially provided by the jacks 11.

Before the compression phase, as soon as the plate 3 is in place inside the machine, the ventilator 7 creates a reduced pressure inside the box formed by the lower plate 3. This reduced pressure is communicated by the apertures 3 to the cavities defined by the blades 91 of the tool 9. This reduced pressure has, in particular, the following roles: (1) it sucks in some of the sheets of the complex 10 inside of the cavities to accentuate the swelling of the complex inside the mould, prior to heat-welding, i.e. the blockage of the assembly; (2) during heat-welding, this reduced pressure evacuates the dangerous or toxic vapours of partial or total decomposition of the material by the effect of the heat of the heatwelding; (3) the reduced pressure retains the complex 10 on the mould 9 after the thermoforming cycle, during the raising of the upper plate 2.This prevents the complex from catching the plate 2 and considerably complicating the extraction of the product from the machine.

After the upper plate 2 has been raised and the rollers 33 are moved back into place, the lower plate 3 can be withdrawn from the machine automatically or manually, to enable the complex 10 to be removed and a new complex to be located ready for subsequent welding.

According to Fig. 6 which shows a section through the lower plate 3 and the upper plate 2 in the working position, the upper plate 2 comprises an anti-adherent layer 21, which is turned towards the complex 10, and a supporting plate 22 to hold the anti-adherent surface 21.

The detail of the lower plate 3 shows the disposition of the apertures 32 and the form of the sheets on the blades 91 of the tool 9.

In Fig. 6, the deformation of the lower layer 10, and of the filler layer 102 of the complex 10 has been exaggerated inside a cavity defined by adjacent cutting blades 9, in the tool 9.

In order to have a heat-welded complex 10 which has a quilted appearance, it is not necessary for the fabric, or more generally the outer sheet 10,, to be made integral over all its surface with the inner sheet or filler sheet 102. However, in certain cases, for example when the complex 10 is subjected to very great wear, for example when this quilted complex is used as a seat cover, chair-back cover, etc. which is subjected to significant shearing stresses, it is advantageous to have slight heat-welding between the sheets 101, 102 without, however, this heat-welding being converted by a crushing of the complex analogous to that achieved by the heat-welding opposite the blades 91.

In order to achieve this slight heat-welding, a sheet 13 is placed inside the cavities of the mould, this sheet 13 being permeable to air and of adequate thickness chosen in dependence upon the nature of the complex 10 and the quilting effect to be achieved.

It can also be envisaged to reduce the height of the blades 91 so that the sheets come to lie in the bottom of the cavities between the blades of tool 9. However, this solution presents disadvantages compared with the former solution. In fact, the height of the quilting cannot be uniform: in this case, sheets 13 of different heights are disposed in the various cavities of the tool 9. Moreover, the sheet 13 distributes the intake of air over all the base of the cavity without closing the apertures 32. This permits the number of apertures 32 to be reduced. In the contrary case, with insufficiently high blades 91, the sheet 10, could be able to close the holes 32 and block the intake of noxious vapours.

During the compression phase of operation, the elastic layer 13 exerts a certain pressure upon the lower sheet 101 to press it against the corresponding surface of the filler sheet 1 2 and to cause surface heat-welding to occur.

The above-described machine may be modified and adapted in a variety of ways.

In one alternative embodiment of the present invention (not illustrated) the lower plate 3 in Fig. 5 is constructed in two parts, one of which is movable and the other is fixed as regards horizontal movement to thus lighten the weight of the movable part emerging from the machine.

In another embodiment (not illustrated), the tool 9 is fixed directly on retractable rollers 33 whilst leaving the box 31 integral with the jacks 11.

In another embodiment the box 31 is subdivided into two parts, one part serving to support the tool 9 during its horizontal translation movements between the position inside the machine and the position outside the machine, and leaving in place inside the machine the elements of the plate 3 which ensure the mechanical holding of the plate and the tool during the compression phase.

Fig. 7 shows a layout diagram of a production plant including a machine 100 constructed according to the present invention.

In the layout diagram of Fig. 7, the machine 100 is not aligned with supply table 101 and discharge table 102.

The supply table 101 receives the complex M comprising the continuous sheets which have not yet been cut up in the appropriate dimensions. These continuous sheets which come from rollers which are not shown are advanced mechanically or by the user, who cuts them with the aid of a transverse cutting device 103, to obtain the cut complex N which has been cut to required dimensions.

The complex N is then located on the tool 9 of the lower plate 3 in the discharge position.

The plate 9 is moved into the machine 100, for the heat-welding operation. At the end of the working cycle, the plate 3 is brought out and the user moves the complex from plate 3 to the discharge station 102.

Fig. 8 shows a diagram of a plant including a a machine 100 in accordance with the present invention, designed for continuous work, the heat-welding operation remaining discontinuous. For this purpose, the passage of the complex M is parallel with the rails 8 of the plate 3. The complex comes from an inlet table 104, in superposed layers, then it passes onto the plate 3. The complex is then conducted simultaneously with the plate 3 into the inside of the machine 100 to undergo the heat-welding operation. At the end of this operation, after the plates have been removed, the complex M is blocked so that it cannot be displaced, and the plate 3 is drawn backwards to resume a new length for the sheet at the level of the supply station 104.

Claims (11)

1. A method of producing a padded and quilted product formed from a cover sheet and a base sheet made of a material having elastic cells which are capable of being compressed, in which the cells are crushed locally according to the outline of the required design for the quilting and the padding to be achieved and the cells in the crushed state are blocked permanently, at least on a porton of the thickness of the base sheet.

2. A product with a padded and quilted surface formed from a cover sheet, a sheet of a a filler material and a base sheet made of a cellulose material, the cover sheet being fixed to the base sheet, following lines and dots, with the permanent compression of one portion at least of the cells of the thickness of the base sheet at the point where this sheet is fixed on the cover sheet.

3. A product as claimed in claim 2, in which a filler material is located between the cover sheet and the base sheet.

4. A product as claimed in claim 2, in which the cover sheet is fixed to the base sheet by gluing.

5. A machine for the shaping and the heat-welding of a complex having a plurality of layers, the machine comprising two plates, one of which at least is adapted to be heated, and which can be used to compress and heat weld the complex, a first plate of said two plates, being arranged to effect an opening and closing movement to enable a complex to be located between the plates, and a second plate being arranged to effect a shorter opening and closing movement to comprises a complex located between said plates, displace- ment members being provided to control the movement of the first plate, these displacement members being double arms which form a toggle articulation, one end being connected to the first plate, the other to a frame of the machine, the articulated joint between the arms of each member, being connected to a control jack, compression members in the form of power jacks, being arranged to control the closure movement of the second plate, the second plate carrying forming tools and being movable between one working position opposite the first plate for the compression operation of the machine, and a disengaged position relative to the first plate, this second plate being provided with translation means which are capable of being retracted when the plate is in the working position opposite the first plate, to occupy a floating position and follow the approach and compression movement of the two plates.

6. A machine as claimed in claim 5, in which suction means are connected to the tool.

7. A machine as claimed in claim 5, in which the second plate comprises one part which remains in the working position opposite the first plate and one sliding part which carries the tool and can move into the disengaged position for the loading and unloading of a complex of sheets.

8. A machine as claimed in claim 5, in which said second plate is adapted to be heated, its surface being covered with an antiadherent layer.

9. A method of producing a padded and quilted product, substantially as hereinbefore described with reference to the accompanying drawings.

10. A product with a padded and quilted surface, constructed substantially as hereinbefore described with reference to and as illustrated in any one of Figs. 1 to 4 of the accompanying drawings.

11. A machine for the shaping and heatwelding of a complex having a plurality of layers, constructed and arranged substantially as hereinbefore described with reference to and as illustrated in Figs. 5 to 7, or Figs. 5, 6 and 8 of the accompanying drawings.