AU2007100311A4 - Mattress - Google Patents

Description

P/00/01 1 Regulation 3.2

AUSTRALIA

00 k- Patents Act 1990 COMPLETE SPECIFICATION INNOVATION PATENT Invention Title: Mattress The following statement is a full description of this invention, including the best method of performing it known to us: ,004960546 2

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Mattress 0Field of the invention The present invention relates to a mattress. This invention finds particular, though not exclusive, application in hot climates.

Background of the invention SFor some people sleeping becomes a hot and uncomfortable experience. When sleeping, an active male, for example, has to lose heat at a rate of ninety watts.

Relatively similar rates are required by women and non-active people. This is a result of the person's basal metabolism and the mattress can become heated by the person's body. This is particularly acute in hot climates, when the room temperature is greater than the person's body temperature and heat is transferred into the person's body. The body deals with these conditions by perspiring once their skin temperature reaches 370.

The evaporation of perspiration has to overcome the transfer of heat into the body and give off enough heat to achieve the ninety watt net outward flow of energy.

The humid conditions caused by perspiration make mattresses a haven for organisms such as bed bugs and dust mites. Bed bugs are a growing health concern in warmer climates and are attracted to the warm moist habitat provided by a mattress.

People react negatively from bed bug bites and allergies.

Manufacturers of mattresses have been attempting to reduce the occurrence of bed bugs for many years. Attempts have been made to develop mattresses where air is mechanically pumped through various vents. These systems are expensive to purchase and run. They are noisy and complicated and the constant flow of cold air can make sleepers chilly rather than comfortable.

It is therefore an object of the present invention to provide an improved mattress that at least in part alleviates the problems associated with known mattresses.

004960546 3 Summary of the invention The present invention has developed through the realisation that a mattress can S be provided in which a plurality of layers are selected such that, when a person is lying on the mattress, natural convection allows air to flow upwardly through the layers of the mattress.

OThe present invention is derived from the observation that as the air surrounding r- the body of a person lying on a mattress receives the heat from the body it becomes 0 less dense and rises. With a suitable mattress construction according to the invention,

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the underlying cooler air can move upwardly to replace it. This cooler air is then heated and the process continues, forming a natural convection current.

The body is able to self regulate the air flow, as the body heats up it draws through more cool air, and as it cools down in draws through less cool air. The convection current also assists the body's perspiration mechanisms to increase evaporation rates.

The layers are selected to minimise the pressure drop as air flows upwardly through the layers. This is achieved by selecting permeable material and maximising the porosity of the layers, whilst still maintaining the functional requirements of each of the individual layers.

According to one aspect of the invention there is provided a mattress having a plurality of layers, wherein when the air surrounding the body of a person lying on the mattress receives heat from the body it becomes less dense and rises, whereby the underlying cooler air moves upwardly through the plurality of layers of the mattress.

According to another aspect of the invention, the mattress may include: a base supporting layer of mesh or open weave construction; a central layer of a resiliently compressible construction; 004960546 4

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N an upper layer of permeable material; and at least one intermediate layer of porous material between the central 00 layer and the top layer; wherein the selection of the materials forming said layers allows air to pass upwardly through said layers.

There may be a second intermediate layer of high porosity material located between the bottom layer and the central layer to provide support to the central layer.

The central layer preferably includes an open coil spring system. Alternatively, the central layer may be made from LatexTM or ViscoTM and include a plurality of wide drilled holes. The bottom layer may be made from a polypropylene gauze material. The top layer is preferably a breathable tick. The second intermediate layer may be a thin layer of reticulated foam.

Preferably, there are two first intermediate layers. The lower intermediate layer may be made from reticulated foam and is preferably selected to protect the uppermost layers from the open coil springs. The upper intermediate layer provides comfort to the user and may be made from reticulated foam of softer construction. It may alternatively or additionally comprise an open cell material formed from a gelatinous elastomer. An example of such a product is the EdizoneTM cellular gel.

The upper layer typically includes a tick. The tick may be made from air circulation fabric such as Cairfull T M fabric. Additionally the upper layer may also include comfort layers, which may be made from sheets of fibre. The fibres may be a natural fibre such as wool.

The mattress according to the present invention is preferably used in conjunction with a slat support base or a specifically designed ensemble base. The ensemble base may be constructed in the standard materials and configuration, with an open central construction. The standard top layer and bottom dust layer are removed. These top and 004960546 CI bottom layers may be replaced with a porous material, such as the material used on the base layer of the mattress.

00 Brief description of the drawings The invention will now be described, by way of example only, with reference to r 5 the accompanying drawings, in which: Figure 1 is a perspective exploded representational view of the layers of a 0 mattress according to an embodiment of the present invention; and Figure 2 is a representative cross-sectional view of a person lying on a mattress according to one aspect of the present invention.

Detailed description of the embodiments Convection is the transfer of heat by mass motion of a fluid, such as air, where the heated fluid is caused to move away from the source of heat, carrying energy with it.

Convection above a hot surface occurs because hot air expands, becomes less dense, and rises. With standard mattresses, there is no cooler air present below a person's body to replace the hot air, as the mattress has trapped the heat from the person's body. Standard mattress construction prevents air flow within the mattress.

In the present invention, a mattress 10 is designed by selecting a plurality of layers to maximise the flow of air upwardly through the layers. The pressure drop as the air flows through each layer is minimised by selecting porous materials. The various layers are shown in a representative exploded view in Figure 1.

The base supporting layer 12 is made from a mesh or open weave material that is porous. This layer is provided as a rigid support to the layers above it. A central layer is represented by layer 14 in the drawings. Central layer 14 may be an open spring system, having a plurality of springs 16. It is preferably that the spring system be open, which means that the springs are not surrounded by pockets of material. The open spring system allows air to freely flow around and between the springs. Alternatively, it p04960540 6 N is envisaged that a Latex

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M core could be used. Latex is preferred as it is C- made from a natural rubber. The LatexTM or ViscoM core would be drilled with a plurality of holes to allow air to flow through the layer. The diameter and spacing of the oO holes would be selected to maximise air flow, whilst maintaining the integrity of the layer for support and comfort.

The central layer 14 may include a foam edge (not shown) that is relatively rigid around the perimeter of the spring system or core. It may also include multi-zoned rigidity, such that in a spring system, the compressibility of the springs in different zones C is varied, to provide appropriate support and comfort levels along the length of the mattress to suit the weight differences along a person's body. In a core layer, the diameter and spacing of the holes vary along the length of the mattress.

An upper layer 18 of permeable material is a tick, which provides the external covering of the mattress 10. The upper layer 18 is relatively thin and can be made from a cotton fabric or an air circulation fabric. Air circulation fabric has an upper and lower sheet of fabric with polyethylene or polypropylene fibres extending between the two sheets of fabric. Air is able to flow through the fabric and fibres, whilst providing a soft upper layer to the mattress. A suitable air circulation fabric is known as CairfulI T M The upper layer 18 may include a layer of wool fibres or other suitable materials.

The upper layer 18 preferably has good wicking properties to draw perspiration away from the person's body. All of the layers of the mattress 10 are preferably permeable to allow any fluids to pass through them.

Between the base layer 12 and the central layer 14, there is provided a first intermediate layer 20. The intermediate layer 20 is made of reticulated foam, which has a broad open cell structure, such that it would allow water to flow through it. The intermediate layer 20 provides support to the central layer 14.

Between the central layer 14 and the upper layer 18, there are two intermediate layers 22, 24. Intermediate layers 22 and 24 function similar to what are well known as 'comfort' layers. The lower intermediate layer 22 protects the upper intermediate layer 004960546 7 N 24, the upper layer 18, and therefore the user, from the springs 16. The lower intermediate layer 22 may be made from reticulated foam. The upper intermediate layer 24 may be made from a relatively softer layer of reticulated foam. Alternatively, an open

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cell material formed from a gelatinous elastomer may be used. An example of such a product is the Edizone T M cellular gel.

It will be appreciated that the various layers may be made from any suitable material that is porous, allowing air to flow upwardly through the layers.

As can be seen from Figure 2, a representation of how the mattress 10 works is shown. Air surrounding the person's body 30 receives the heat from the body and it becomes less dense and rises, as shown by arrows A. The underlying cooler air then moves upwardly through the layers of the mattress 10 to replace it, as shown by arrows B. This cooler air is then heated and the process continues, forming a natural convection current. As the plurality of layers of the mattress are selected to maximise flow of air upwardly through the mattress, by using porous materials and open cell structures, the underlying cooler air is able to flow freely through the mattress 10 to cool down the user's body. This prevents hot air from becoming trapped in the mattress.

The advantage of the mattress 10 is that a constant flow of air through the mattress during sleep reduces the mattress humidity and thus reduces the incidence of bed bugs and dust mites. Unlike mechanical movement of air, the present invention does not generate air speeds too great, which results in people getting cold rather than being comfortable.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

Claims (4)

1. A mattress having a plurality of layers, wherein when the air surrounding the 0_ body of a person lying on the mattress receives heat from the body it becomes less dense and rises, whereby the underlying cooler air moves upwardly through the plurality of layers of the mattress.

2. A mattress including: a base supporting layer of mesh or open weave construction; a central layer of a resiliently compressible construction; an upper layer of permeable material; and at least one intermediate layer of porous material between the central layer and the top layer; wherein the selection of the materials forming said layers allows air to pass upwardly through said layers.

3. A mattress according to claim 1 or 2, wherein the central layer comprises latex.

4. A mattress according to claim 2, wherein an upper intermediate layer comprises an open cell material formed from a gelatinous elastomer. An ensemble base for use with the mattress according to any one of claims 1 to 4, the ensemble base having an open central construction.