EP1240852B2 - Mattress - Google Patents

Abstract

The mattress comprises a layer of visco-elastic foam (1). A first resilient fabric (2) partially covers a first face of the foam and a second fabric (3) partially covers the second opposite face of the foam. Sewing points (4) extending between the two fabrics pass through the foam layer.

Description

The present invention relates to a mattress comprising at least one layer of foam.

Mattresses or cushions made by sewing a layer of elastic (non-viscoelastic) foam with one or more non-elastic fabrics have been proposed on the market.

Such mattresses are for example made by means of a machine of the type described in US 5,974,994 .

There are also known single-layer mattresses made of viscoelastic foam, said mattresses having a thickness of more than 2 cm to properly recover the body shapes. Such mattresses are increasingly used for medical purposes. Such mattresses are heretofore covered with a sheet to prevent direct contact of the mattress with the body of the patient or a part thereof. Such a sheet creases easily and relative movements of the sheet relative to the mattress are common.

Tests were then performed on existing sewing machines for the preparation of mattresses consisting of a layer of foam sewn to two non-elastic fabrics. In these tests, the traditional elastic foam layer was replaced by a layer of viscoelastic foam. It was thus noted that as soon as the layer of viscoelastic foam had a thickness of more than about 1 cm, the seam of non-elastic fabrics with interposition of the viscoelastic layer was not possible and the parts possibly sewn together showed deformations unwanted. In addition, in a mattress having a layer of viscoelastic foam of about 1 cm thick, the viscoelastic properties of the mattress are useless, since such a mattress does not allow to properly resume the body shapes.

It was then tried to make mattresses comprising at least one layer of viscoelastic foam with a thickness greater than 1.5 cm, in particular greater than 2 cm, for example between 1.6 cm and 10 cm thick, preferably from 2 cm to about 8 cm.

To achieve such mattresses, it was then realized that it was advantageous to use at least one elastic fabric and advantageously achieve the stitches by means of one or more rounded needles, two adjacent stitches being advantageously spaced from each other by 0.3 mm to 10 mm, preferably from 0.4 to 0.8 mm, in particular of approximately 0.5 mm.

The subject of the invention is therefore a mattress or layer according to claim 1.

For example, the viscoelastic foam layer has a thickness of at least 2 cm, preferably at least 4 cm, preferably at least 6 cm. Advantageously at least the first fabric or the second fabric is elastic so as not to lose or reduce the viscoelastic properties and properties of the foam. In particular, the first fabric or the second fabric has at least one greater elasticity than that of the viscoelastic foam layer.

Particularly advantageously, the first fabric and the second fabric of the mattress are elastic fabrics of equal or different elasticity, in particular of the same elasticity.

Preferably, the first elastic fabric has a higher elasticity than the viscoelastic foam. For example, the first elastic fabric is a fabric capable of undergoing maximum tensile elastic deformation in two plane directions perpendicular to each other, this maximum tensile elastic deformation of the fabric being greater than the maximum viscoelastic deformation of the viscoelastic foam layer. This makes it possible to better preserve the viscoelastic properties of the viscoelastic foam layer.

According to one embodiment, the second fabric is a flexible fabric having an elasticity equal to or different from that of the first fabric, in particular viscoelastic foam, preferably less than that of the first fabric, in particular the viscoelastic foam layer.

The first fabric and / or the second fabric may optionally have a variable elasticity, that is to say one of which has an elasticity different from that of another part.

The viscoelastic foam is advantageously perforated by means of one or more rounded tip needles. Such perforation has the advantage of reducing the number of tear primer.

According to a feature of an embodiment, the mattress has stitching lines formed from adjacent stitches, said stitches being made with a spacing such that the density of adjacent and successive stitching stitches per unit length is at least 10 stitches per 10 cm of stitching line; sewing, preferably from 10 to 50 stitches per 10 cm seam line. The distance separating two successive stitches is advantageously between 0.3 and 1 cm, preferably between 0.4 and 0.8 cm, in particular about 0.5 cm.

• matelas conservant ses propriétés viscoélastiques, bien qu'étant associé à une ou des housses,
• le premier tissu élastique peut être un tissu élastique de qualité permettant de former un revêtement extérieur ;
• le premier tissu est par exemple un tissu éponge ;
• facilité de fabrication,
• lavage facile ;
• possibilité de former par des points de couture des zones de viscoélasticité différente ;
• les tissus suivent à tout moment la forme de la couche de mousse viscoélastique, malgré la reprise plus lente de la forme initiale de la mousse après sa compression,
• etc.

Advantages of the mattress according to the invention are:

• mattress retaining its viscoelastic properties, although being associated with one or more covers,
• the first elastic fabric may be a quality elastic fabric for forming an outer covering;
• the first fabric is for example a terry cloth;
• ease of manufacture,
• easy washing;
• possibility of forming different areas of viscoelasticity with stitches;
• the tissues follow at all times the shape of the viscoelastic foam layer, despite the slower recovery of the initial shape of the foam after compression,
• etc.

Features and details of mattress according to the invention will become apparent from the following description in which reference is made to the accompanying drawings.

• la figure 1 est une vue de haut d'un matelas suivant l'invention,
• la figure 2 est une vue en coupe selon la ligne II-II du matelas de la figure 1,
• la figure 3 est une vue similaire à celle de la figure 2, si ce n'est que le matelas est comprimé ,
• la figure 4 est une vue en coupe d'une autre forme de réalisation d'un matelas suivant l'invention.

In these drawings,

• the figure 1 is a view from above of a mattress according to the invention,
• the figure 2 is a sectional view along line II-II of the mattress of the figure 1 ,
• the figure 3 is a view similar to that of the figure 2 , except that the mattress is compressed,
• the figure 4 is a sectional view of another embodiment of a mattress according to the invention.

The layer of viscoelastic foam is for example a polyether foam, in particular polyurethane, density (uncompressed state) of between 25 kg / m ³ and 100kg / m ^3, preferably from 40kg / m ³ to 70kg / m ^3. The foam is open-celled or closed, but preferably open-celled or substantially open-celled.

Such a layer of foam is for example made of polyurethane, and is open cell. The layer, which may be of the variable thickness type or not, or the type with peak and recess is advantageously a layer of substantially constant thickness of about 4 to 6 cm.

• Dureté par identation (N) à 8°C à 25% comprise entre 120 et 330, à 40% comprise entre 150 et 500, et à 65% comprise entre 260 et 1100 ;
• Dureté par identation (N) à 23°C à 25% comprise entre 55 et 125, à 40% comprise entre 70 et 160, et à 65% comprise entre 130 et 300 ;
• Dureté par identation (N) à 37°C à 25% comprise entre 40 et 90, à 40% comprise entre 60 et 110, et à 65% comprise entre 110 et 220 ;
• Un indice de confort de 2 à 3, en particulier d'environ 2,4 ;
• Une résistance à la compression (Kpa) 40% comprise entre 1 KPa et 5Kpa, en particulier entre 1,5 et 3,5KPa,
• Une densité brute comprise entre 20 et 100kg/m³, en particulier comprise entre 40 et 60kg/m³, par exemple environ 50kg/m³ ;
• Une densité nette comprise entre 20 et 100kg/m³, en particulier comprise entre 40 et 60kg/m³, par exemple environ 45-50kg/m³ ;
• Un allongement à la rupture (ISO 1798) compris entre 100% et 300%, avantageusement entre 120% et 200%, par exemple de 140% à 170%,
• Une résistance à la traction (ISO 1798) comprise entre 25Kpa et 150Kpa, voire plus, avantageusement de 50KPa à plus de 100Kpa ;
• Une rémanence à la compression (ISO 1856) de maximum 5%, de préférence de maximum 3% ;
• Une résistance au feu, par exemple MVSS 302 (100mm/minute).

The viscoelastic layer has the following properties:

• Hardness by identification (N) at 8 ° C at 25% between 120 and 330, at 40% between 150 and 500, and at 65% between 260 and 1100;
• Hardness by identification (N) at 23 ° C at 25% between 55 and 125, at 40% between 70 and 160, and at 65% between 130 and 300;
• Hardness by identification (N) at 37 ° C at 25% between 40 and 90, at 40% between 60 and 110, and at 65% between 110 and 220;
• A comfort index of 2 to 3, especially about 2.4;
• A compressive strength (Kpa) 40% of between 1 KPa and 5Kpa, in particular between 1.5 and 3.5KPa,
• A bulk density of between 20 and 100 kg / m ³ , in particular between 40 and 60 kg / m ³ , for example about 50 kg / m ³ ;
• A net density of between 20 and 100 kg / m ³ , in particular between 40 and 60 kg / m ³ , for example about 45-50 kg / m ³ ;
• An elongation at break (ISO 1798) of between 100% and 300%, advantageously between 120% and 200%, for example from 140% to 170%,
• A tensile strength (ISO 1798) of between 25 Kpa and 150 Kpa or more, advantageously from 50 KPa to more than 100 Kpa;
• Compression remanence (ISO 1856) of not more than 5%, preferably not more than 3%;
• Fire resistance, for example MVSS 302 (100mm / minute).

Unless otherwise stated, the physical values are measured at 23 ° C, 50% humidity and after 48 hours storage. The measurements are taken in the middle of a product block.

Such viscoelastic layers are, for example, but advantageously "EUCATHERM C" ® layers, for example TC50-H, TC50-M and TC50-W sold by KABELWERK EUPEN AG.

This layer of viscoelastic foam 1 is connected to two elastic fabrics 2, 3, said fabrics 2, 3 having greater elasticity than that of the foam 1. The tissues 2, 3 are sewn together with the interposition of the layer 1. Sewing 4 are made thanks to rounded head needles. These stitches 4 form seam lines 4A, 4B. The sewing points of a line are arranged relative to one another so that the distance separating two successive sewing points is approximately 5 mm. Sewing stitches that are too close together damage the viscoelastic foam, while stitches that are too far apart do not ensure a good follow-up of the fabric compared to the viscoelastic foam.

The elastic fabrics 2,3 which may have the same elasticity or different elasticities. These fabrics are for example made of stretch fabrics, such as Nicky-stretch, terry cloth, jersey fabric, knit fabric, etc. ; woven fabric, woven such as woven with crossed threads, woven plain or taffeta, satin, etc., fabrics provided with a coating, for example a polyurethane coating, threaded fabric, synthetic leather, natural leather, composite fabric, membrane, etc. The fabrics are made of synthetic material, natural, mineral, or a mixture thereof. For example, the fabrics are made of cotton, polyester, elastomer, viscose, nylon, blends thereof, for example a cotton / polyester blend, for example 75% cotton / 25% polyester, 70% cotton / 30% polyester. It is also possible to use materials such as Scotchgard, Hydrofoil, Medicott, Sanfor, CS-reinforcement (casein), etc., and mixtures thereof. These fabrics have longitudinal and axial elastic elongation characteristics sufficient to take up the deformations or hollow of the foam layer 1. Thus, the fabrics are able to follow the foam layer correctly. For example, the fabrics have an elastic elongation of at least 15%, in particular at least 25%, preferably at least 50%, preferably both in the longitudinal direction of the fabric and both in the axial direction of the fabric.
The elastic fabrics 2, 3 are advantageously sewn with the foam layer in an unstretched or substantially unstretched state, that is to say for the tissues 2, 3 to generate an elastic force on the foam or between sewing which is a function of the crushing of the foam at the stitching points and / or the swelling of the crushed foam after sewing. This slight elastic stretching ensures that the tissues 2,3 correctly follow the movements of the viscoelastic foam during the use of the mattress, for example during the compression of the viscoelastic foam, as well as during the return of the latter in a state less compression.

For example, elastic fabrics 2,3 are stretched elastically from 0 to 50%, for example less than 15%, or according to another example of more than 15%, advantageously more than 20%, preferably 25 to 50%. % in at least one direction extending between two adjacent seam lines, for example in a direction of which at least one component is substantially perpendicular to the two adjacent seam lines.

Between two seam lines, the fabrics 2,3 are stretched or slightly stretched (when making the stitches) relative to their stable or unstretched state, with a stretching rate sufficient for a compressed position of the viscoelastic foam between the seam lines, the fabrics 2,3 located between said seam lines are always under a slight elastic tension. (see figure 3 )

The mattress shown in figure 1 is for example manufactured as follows:

A layer of viscoelastic foam 1 is placed on a plate and between two elastic fabrics.

Tissues 2,3 are not subjected to axial and longitudinal stretching.

The assembly formed by the viscoelastic foam layer and the elastic fabrics is compressed, for example to a state of maximum or substantially maximal elastic compression. Sewing stitches (tray stitching) are then performed to associate the fabrics 2,3 with each other, with the viscoelastic foam layer interposed. These stitches are made by means of a round-headed needle so as not to damage the viscoelastic foam layer and the elastic fabrics. These stitches advantageously define one or more lines, preferably a network of sewing lines that touch or intersect. The elastic fabrics 2,3 are then slightly stretched by the swelling of the viscoelastic foam and by the maintenance of crushed portions of the viscoelastic foam at the stitches. The distance between two successive stitches is set between 3 mm and 10 mm, with a preference for about 5 mm.

According to another manufacturing method, a machine of the type described in the document is used. US5974994 except that a layer of viscoelastic foam 3 to 8 cm thick and upper and lower elastic fabrics are used, round-headed needles are used to make stitching lines (continuous stitching) , and that the distance between two successive stitches is 0.5cm.
In the mattress according to the invention, it is advantageous for the elastic fabrics to be in direct contact with the viscoelastic foam layer. Also advantageously, the restoring force of the elastic fabrics (caused by stretching thereof) is less than the expansion force of the compressed viscoelastic foam. In this case, the compressed parts of the viscoelastic foam are obtained by virtue of the stitches and the degree of compression of the foam at the location of the seam at the time of sewing.

To the figure 4 , there is shown a mattress sewn in the form of a cover, for example adapted to receive a cushion.

The mattress according to the invention has many applications or uses, for example in bedding, hospital mattresses, baby mattresses, mattress cover, cushion cover, seat cover (for example car), protective layer (for example to protect objects during transport), ergonomic cushion, extra mattress, anti-decubitus mattress, acoustic absorbing mattress, thermal insulation blanket, packaging, mattresses allowing better blood circulation or allowing a better sleep, etc. One or the elastic fabrics may be made of a waterproof material or not. The mattress according to the invention therefore has applications in orthopedics, medicine, acoustics, energy, shock absorption, etc. The viscoelastic foam presents a variable hardness as a function of the temperature and by a very weak resilience, thus allowing a very strong absorption of the deformation energy. The foam advantageously has a thermovariability, so that the foam compressed by a human body first opposes a certain resistance, this decreasing resistance to become very low once the temperature of the foam is about 37 ° C. Optionally, the viscoelastic layer may be profiled, for example to have depressions and peaks. However, given the properties of the foam, the presence of such hollows or peaks is not absolutely necessary, except for very particular application. Optionally also the viscoelastic foam layer may be provided with an armature or an inner mesh, preferably flexible or deformable, for example to give and maintain a particular shape to the mattress.

Claims (8)

1. Layer or mattress comprising:

   - a layer of viscoelastic foam (1) with a thickness greater than 1.5 cm, preferably comprised between 1.6 and 10 cm, said foam having two opposite faces,

   - a first resilient fabric (2) at least partially covering a first face of the layer of viscoelastic foam,

   - a second fabric (3) which is resilient or not, advantageously resilient, at least partially covering the second face of the layer which is opposite the first face, and

   - sewing points (4) extending between said first resilient fabric and said second fabric passing through the layer of viscoelastic foam,

   the layer or mattress having compressed zones, one or the compressed zones being in a state of compression such that the thickness of the foam of the compressed zone corresponds from 10 to 50% of the thickness of the foam before compression, while the first fabric and/or the second fabric stitched to the layer of viscoelastic foam are in a stretched or slightly stretched state.
2. Layer or mattress according to claim 1, characterized in that the layer of viscoelastic foam (1) has a thickness of at least 2 cm, advantageously of at least 4 cm, preferably of at least 6 cm.
3. Layer or mattress according to claim 1 or 2, characterized in that the second fabric (3) is a resilient fabric.
4. Layer or mattress according to any one of the previous claims, characterized in that the first resilient fabric (2) has a resilience which is greater than that of the viscoelastic foam (1).
5. Layer or mattress according to the previous claim, characterized in that the first resilient fabric (1) is a fabric capable of undergoing a maximum tensile elastic deformation in two plane directions which are perpendicular to each other, this maximum tensile elastic deformation of the fabric being greater than the maximum viscoelastic deformation of the layer of viscoelastic foam.
6. Layer or mattress according to any one of the previous claims, characterized in that the second fabric (2) is a flexible fabric having a resilience which is equal to or different from that of the first fabric, in particular less than that of the first fabric, in particular of that of the layer of viscoelastic foam (1).
7. Layer or mattress according to any one of the previous claims, characterized in that the viscoelastic foam (1) is perforated using a needle or needles with a rounded point.
8. Layer or mattress according to any one of the previous claims, characterized in that it has sewing lines (4A, 4B) formed by adjacent sewing points (4), said points being produced with a spacing such that the density of adjacent and successive sewing points, per unit length , is at least 10 sewing points per 10 cm of sewing line, advantageously 10 to 50 sewing points per 10 cm of sewing line, the distance between two successive sewing points advantageously being comprised between 3 mm and 10 mm, preferably between 4 mm and 8 mm.

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