EP0099313B1 - Waterproofed cover sheet - Google Patents

Abstract

1. A waterproofed covering sheet particularly intended to recover and protect the mattress of bedding for children and adults and for the incontinence, especially comprising a central tray (2) of tissue, partly waterproofed by a plasticized film (4), surrounded with an edge (3) having on its periphery elastic or at the very least retractable means, characterized in that the central tray (2) and the edges (3), making up the covering sheet, are in the form of a same piece of a non discontinue, extensible and mesh-provided tissue and that it includes a zone of stretched tissue, waterproofed on all or part of the surface intended to recover the upper face of the mattress, making up the waterproof zone, and a non stretched, extensible, non discontinue and permeable zone, at the periphery of the waterproof zone of tissue, making up the rest of the covering shett, and that it presents a homogeneity of the tissue on the periphery of the waterproof zone.

Description

The invention relates to a waterproof fitted sheet, its manufacturing method for waterproofing it and a device for implementing said method.

The invention will particularly find its application in the field of bedding and in particular to cover and protect the mattresses of beds of children or adults and for incontinence.

Currently, fitted sheets have a central tray intended to cover the upper face of the mattress, this tray is surrounded by a rim which covers the edge of the mattress, this rim is provided on its periphery with an elastic band to keep the fitted sheet applied. on the mattress. This type of fitted sheet can be made in a single piece of fabric or possibly in several pieces of fabric which are then attached and sewn together.

Currently, there are known fitted sheets with an impermeable area which are generally made of several pieces of fabric assembled by stitching. For example, the waterproof zone is produced by applying a plastic film to a piece of fabric of substantially the same size, then the assembly is sewn onto a piece of complementary fabric to form the fitted sheet.

This provision is imposed in particular by the waterproofing of the fitted sheet. In fact, generally, a plastic film is deposited in a strip on a piece of fabric by calendering allowing the waterproofing of a fabric continuously. Then, the roll of waterproof fabric obtained is cut into waterproof pieces which are sewn to make the fitted sheet.

Insofar as during the calendering, the width of the plastic film is less than that of the fabric, it is possible to obtain a certain homogeneity of the waterproofing in the transverse direction since there is no discontinuity between the two lateral strips of fabric and the central part which receives the plastic film. But later, in the longitudinal direction, there will be a seam which will remove the homogeneity which had been obtained initially.

Furthermore, it is known from the British document GB-A-2 012159 a fitted sheet waterproofed by a film glued to the back of the fitted sheet.

More particularly, this fitted sheet consists of a central plate surrounded by a rim having on its periphery elastic means formed from a piece of fabric previously waterproofed with a plastic film, the piece of fabric then being cut to each of its angles then sewn to form the corners of the fitted sheet.

As in the technique described above, the waterproofing of the fitted sheet is carried out beforehand by bonding to the basic textile piece a plasticized film either by calendering between pressure rollers, or directly by spreading the product in the liquid state on the surface of fabric to form the underside of the fitted sheet. The fitted sheet made from the waterproof laminate fabric-plastic film is a semi-rigid product made from a single non-stretch material used on the entire surface of the fitted sheet, the tray and rim being cut to be shaped.

This embodiment described in the British patent does not allow easy installation of the fitted sheet on the mattress and does not allow a certain flexibility of the sheet during use because it will rather have a rigid appearance like that of "cardboard". In addition, the mattress can hardly breathe through the waterproof plastic material.

Thus the current waterproof fitted sheets are completely uncomfortable because either they suffer from a discontinuity between their waterproof zone and the rest of the fabric due to the presence of the seams, or because they are semi-rigid and non-stretchable removing any flexibility from the sheet during use and preventing breathing of the mattress.

In addition, with regard to their manufacture, the need to sew the waterproof zone or to form it by sewing leads to higher manufacturing times penalizing their cost price.

In addition, the presence of the seams makes them particularly fragile at this level and in one case as in the other, there is often tearing along the seam lines.

The main object of the present invention is to provide a waterproof fitted sheet which has perfect homogeneity of its fabric over the entire periphery of the waterproofed area, the fitted sheet having no seams which makes it particularly comfortable and resistant.

Another object of the present invention is to provide a waterproof fitted sheet which is in the form of the same piece of non-discontinuous stretch fabric with mesh allowing an installation during its easy use and keeping a certain flexibility and the possibility the mattress to breathe which increases the comfort of use.

Another object of the present invention is to present a waterproof fitted sheet, made of an extensible fabric, and which provides substantial savings in terms of its production, in particular by saving the area of the piece of fabric used for making.

Another object of the present invention is to present a manufacturing method for waterproofing the fitted sheet by hot application of a plastic film by which the risks of air bubbles forming when welding the film on the fabric are eliminated.

Another object of the present invention is to provide a device for implementing the method of manufacturing said fitted sheet.

Other objects and advantages of the present invention will emerge during the description which follows, which is however only given for information and which is not intended to limit the invention.

The waterproof fitted sheet of the present invention, intended in particular to cover and protect bedding mattresses for children or adults and for incontinence, comprising in particular a central cloth tray, partially waterproofed by a plastic film, surrounded by a rim having elastic or at least retractable means on its periphery is characterized in that the central plate and the flanges, constituting the fitted sheet, are in the form of a single piece of non-discontinuous stretch mesh fabric and that it includes a zone of fabric in the stretched state, waterproofed over all or part of the surface intended to cover the upper face of the mattress, constituting the waterproof zone, and a non-stretched, stretchy, non-discontinuous, permeable zone at the periphery of the waterproof fabric area constituting the rest of the fitted sheet and that it has a homogeneity of the fabric on the periphery of the waterproofed area.

The manufacturing process for waterproofing a fitted sheet according to the invention, the reverse side of the fitted sheet being intended to be applied to the mattress, is characterized in that the stretchy fabric composing the fitted sheet is stretched to open its stitches at least in the area to be waterproofed, a piece of plasticized film cut to the dimensions of the desired waterproof area is applied, by hot pressing on the back of the fitted sheet in the area of the tray to be waterproofed, the air is evacuated present in the meshes of the stretch fabric simultaneously with pressing to allow the penetration of the plasticized material between the meshes.

The device for implementing the manufacturing method according to the invention is characterized in that it is in the form of a mattress or support frame, substantially rectangular, on which the fitted sheet to be waterproofed is placed, the mattress or support frame being expandable to place the area of fabric to be waterproofed in a stretched state, which mattress or support frame comprising on its surface, at least in the area in contact with the area of the sheet to be waterproofed, means for absorbing or evacuate the air present in the open stitches of the stretched fabric.

• La figure 1 schématise un drap housse imperméable développé.
• La figure 2 schématise le dispositif pour la mise en oeuvre du procédé selon l'invention.
• La figure 3 représente une coupe transversale de la surface du matelas support de pressage dans un mode préférentiel de réalisation.
• La figure 1 représente, un drap housse imperméabilisé qui a été développé pour observer les différentes parties qui le constituent. Ce drap housse 1 est réalisé en tissu, ce terme devant être pris au sens large et comprend toutes les réalisations de surfaces textiles extensibles telles que notamment jersey, tricot, ... Le drap housse présente un plateau central 2 qui est destiné à recouvrir la face supérieure du matelas de literie, ce plateau 2 est entouré par un rebord 3. Ce rebord 3 présentera avantageusement une parfaite continuité avec ce plateau 2 en étant réalisé dans une même pièce de tissu non discontinue. Le rebord 3 est destiné à couvrir les chants du matelas de literie, ce rebord 3 est bordé extérieurement par des moyens élastiques ou tout au moins rétractables afin d'appliquer le drap housse sur le matelas à couvrir.

The invention will be better understood if reference is made to the description below, as well as to the accompanying drawings which form an integral part thereof.

• Figure 1 shows schematically a waterproof fitted sheet.
• Figure 2 shows schematically the device for implementing the method according to the invention.
• FIG. 3 represents a cross section of the surface of the pressing support mattress in a preferred embodiment.
• FIG. 1 represents a waterproof fitted sheet which has been developed to observe the various parts which constitute it. This fitted sheet 1 is made of fabric, this term having to be taken in the broad sense and includes all the achievements of extensible textile surfaces such as in particular jersey, knitting, ... The fitted sheet has a central plate 2 which is intended to cover the upper face of the bedding mattress, this plate 2 is surrounded by a flange 3. This flange 3 will advantageously have perfect continuity with this plate 2 by being produced in the same piece of non-discontinuous fabric. The rim 3 is intended to cover the edges of the bedding mattress, this rim 3 is bordered externally by elastic or at least retractable means in order to apply the fitted sheet to the mattress to be covered.

In addition, the plate 2 has an impermeable zone 4. According to the invention, this impermeable zone 4 will have perfect homogeneity with the whole of the plate 2, that is to say that it will have no seams on its periphery.

The waterproof area will be composed by a plastic film applied to fabric. To guarantee perfect homogeneity, according to the invention, the piece of fabric to which the plasticized film is applied will be identical to the piece of fabric making up the rest of the tray 2. Thus, the tray 2 will consist of a single piece of fabric, the waterproof zone 4 being obtained by applying a plastic film on said piece of fabric.

In this way, there is no discontinuity of the fabric on the periphery of the impermeable zone 4.

In the waterproofed area, the fabric that makes up the tray 2 will preferably be in the stretched state. The plastic film which is welded to the fabric makes it possible to immobilize the fibers making up the fabric in a certain state. According to the invention, the plastic film will immobilize the texture of the fabric so that, for example, in the case of knitting, the stitches are stretched. By its flexibility, the plastic film will of course allow the folding of the sheet but on a small scale, the plastic film will impose a tension on the fibers of the fabric.

Advantageously, an extensible fabric will be used to make the tray 2. In this way, the plastic film will cover an area of fabric in the stretched state. This stretching will not however be exaggerated beyond measure in order not to cause a distension of the fabric and furthermore it is necessary that the fabric nevertheless forms a structure for the plastic film.

In this way, the waterproofed zone which has a plastic film placed on a stretched fabric allows a saving of material at the level of the fabric surface used. Since, in this case, the surface of the waterproofed area is made with stretched fabric and therefore larger than the originally unstretched piece of fabric.

It is possible to draw according to the two dimensions of the plane or according to a single dimension.

According to the method of manufacturing the waterproofing of the fitted sheet according to the invention, which consists in coming to apply a plasticized film on fabric, one will realize preferably the application of the plasticized film on the back of the fitted sheet, that is to say the side of the fitted sheet which will be applied against the bedding mattress. Thus, the fitted sheet will present greater comfort since it will present externally only a piece of fabric.

Unlike the current methods of manufacturing waterproof fitted sheets, according to the process of the present invention, the piece of plastic film will be applied to the fabric fitted sheet already produced. The piece of plastic film will be cut to the dimensions of the desired waterproof area and then it will be applied by hot pressing on the back of the fitted sheet in the area of the tray to be waterproofed, which will allow the plastic film to be held on the fabric by welding.

Simultaneously with this hot pressing operation, the air present in the fabric will be evacuated. In this way, the risk of creating bubbles at the weld of the plastic film will be eliminated.

According to a preferred embodiment of the waterproofing method of the invention, the fabric making up the fitted sheet will be tensioned, at least in the zone to be waterproofed, before the application of the plasticized film. In this way, advantageously using stretch fabrics, the dimensions of the fitted sheet will be artificially increased. In fact, the plasticized film will be applied to a surface of stretched fabric and will immobilize the texture of the fabric in this position by welding, which will allow a substantial gain by saving the surface of fabric on which the piece of plasticized film will be applied.

It is obvious that the rest of the piece of fabric which has not received the application of the plastic film will retract later. The tensioning of the fabric should however be moderated so as not to distend it and in particular that the piece of fabric no longer provides a support for the satisfactory plastic film.

Figure 2 shows schematically a device for implementing the method of the invention. It is more particularly a support mattress 5 on which will be fitted the fitted sheet to be waterproofed. This support mattress 5 has dimensions similar to those of the bedding mattress for which the fitted sheet is intended or preferably smaller.

However, the support mattress 5 will have particular properties and in particular a possibility of expansion as illustrated by the arrows 6. In this way, after having put the fitted sheet on the support 5, the latter will be expanded which will have for consequence of placing the fitted sheet under tension. In the case of FIG. 2, an expansion in two directions of the transverse plane has been shown diagrammatically, but an expansion in one direction could have been envisaged.

Once the support mattress has expanded, it is possible to apply the plasticized film to the surface of the fitted sheet to waterproof its surface. Because it is desired to place the plastic film on the back of the fitted sheet, it will be necessary to place the fitted sheet upside down on the support mattress 5.

The plastic film is applied to the fabric of the stretched fitted sheet, which provides the advantages described above.

After application of the plastic film and when it has cooled, the support mattress is retracted again and the fitted sheet is released. When for example the entire surface of the tray has been waterproofed, it follows that the waterproofed fitted sheet obtained is larger than the originally fitted sheet.

According to a preferred embodiment of the support mattress according to the invention, it will present on its surface at least in the zone in contact with the zone of the waterproof fitted sheet, means for absorbing or evacuating the air. Thus, during the pressing operation, the air contained in the fabric can be evacuated.

Figure 3 shows schematically a preferred embodiment of these means. According to the invention, the frame 7 of the support mattress will present on its surface a cushion 8 made of cellular material. In this way, when the plastic film 9 is applied to the piece of fabric 10 by means of a heating press 11, the air present in the piece of fabric 10 can penetrate into the cellular material 8 and flow through the alveoli to the outside. The foam material may advantageously be foam resistant of course to the temperature.

According to another design of the device intended for the implementation of the method according to the invention for making a waterproof fitted sheet, this device comprises a tubular frame of substantially rectangular shape with the dimensions of a traditional bedding mattress. The fitted sheet is placed on the frame of the device. To do this, simply wrap the frame with a fitted sheet, the edge of which folds around the frame, remaining in this position using the peripheral elastic. It should be noted that the fitted sheet being placed on a frame whose dimensions are substantially the same as those of a traditional bedding mattress, the fitted sheet will be placed on the frame in the stretched state.

Then, the entire sheet positioned on the frame is placed flat on a cushion enjoying the special properties set out above. This cushion will preferably be made of a cellular material such as foam. Then, we have the plastic film on the fitted sheet stretched over the frame where we want to waterproof this fitted sheet.

Finally, simply apply the heated plate of a press on the plastic film to weld it on the fitted sheet which rests on the cushion. The alveolar constitution of the cushion will have allowed, during the application of the press plate, to absorb the air contained in the fabric of the fitted sheet in order to avoid any formation of bubbles of the plastic film.

Once the welding has been carried out, the hot plate of the press can be released and the fitted sheet can be removed from the frame, this fitted sheet is then waterproofed.

In order to provide a feedback against the pressure exerted by the press plate, it will be advantageous to have a cushion whose dimensions will be at least greater than those of the plastic film which must be fully covered by the heated plate of the press to be welded properly.

Good results have been obtained by using stretch loop jersey as the fabric. It is possible, for example, to obtain a waterproof fitted sheet with a total width of 1.94 m starting from a piece of fabric with a width of 1.60 m, resulting in a gain of 34 cm in width. In this case, the plastic film itself had a width of 1.40 m.

The plastic film may be a PVC with a thickness of about 20/100 mm which will be applied at a temperature between 100 and 200 ° C, preferably 200 ° C. The force of application of the plastic part will be limited to 58.8 N (6 kg) so that the plastic film nevertheless remains superficial on the piece of fabric and does not penetrate it too deeply.

Claims (4)

1. A waterproofed covering sheet particularly intended to recover and protect the mattress of bedding for children and adults and for the incontinence, especially comprising a central tray (2) of tissue, partly waterproofed by a plasticized film (4), surrounded with an edge (3) having on its periphery elastic or at the very least retractable means, characterized in that the central tray (2) and the edges (3), making up the covering sheet, are in the form of a same piece of a non discontinue, extensible and mesh-provided tissue and that it includes a zone of stretched tissue, waterproofed on all or part of the surface intended to recover the upper face of the mattress, making up the waterproof zone, and a non stretched, extensible, non discontinue and permeable zone, at the periphery of the waterproof zone of tissue, making up the rest of the covering shett, and that it presents a homogeneity of the tissue on the periphery of the waterproof zone.

2. A process for waterproofing a covering sheet according to claim 1, the reverse of the covering sheet being intended for applying itself on the mattress, characterized in that :

the extensible tissue composing the covering sheet is stretched in order to open its meshes at least in the zone to be waterproofed (4),

a piece of plasticized film, cut in accordance with the dimensions of the desired waterproof zone, is applied by warm pressing, on the reverse of covering sheet in the zone of the tray to be waterproofed,

the air present in the meshes of the extensible tissue is simultaneously removed during the pressing in order to allow the penetration of the plasticized material between the meshes.

3. A device for making use of the process according to claim 2, characterized in that it has the form of a mattress or supporting frame, appreciably rectangular, onto which the covering sheet to be waterproofed is placed, the mattress or supporting frame being expansible for bringing about the zone of the tissue to be waterproofed in the stretched state, said mattress or supporting frame comprising, on its surface, at least in the zone in contact with the zone of the sheet to be waterproofed, means for absorbing or removing the air present in the open meshes of the stretched tissue.

4. A device according to claim 3, characterized in that the means for absorbing or removing the air present in the open meshes of the stretched tissue are in the form of a cushion disposed at the surface of the mattress or supporting frame, and composed of alveolar material, such as foam.

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