Patent Description:
The invention relates to a shaped body comprising a spring and foam and uses thereof.

Mattresses such as those formed of polyurethane foam, latex foam, and the like, with or without coiled springs, are generally known in the art. One of the ongoing problems associated with mattress assemblies is user comfort. To address the issues of user comfort, these mattresses are often fabricated with multiple foam layers having varying properties, such as density and hardness, among others, to suit the needs of the intended user. More recently, manufacturers have employed so-called memory foams, also commonly referred to as viscoelastic foams. These foams are often structures having both closed and open cells but, in some instances, may be reticulated foam structures. When used in a mattress, the memory foam conforms to the shape of a user when the user exerts pressure onto the foam, thereby minimizing pressure points from the user's body. The memory foam then returns to its original shape when the user and associated pressure on the memory foam is removed. However, the return to the original shape of the memory foam is a relatively slow process because of the viscoelastic cellular structure of these types of foams.

As is known, a polyurethane is formed from the reaction from a polyol (an organic compound having multiple groups) with a di- or poly-isocyanate. Examples of a di-isocyanate is TDI or toluene di-isocyanate. An example of a poly-isocyanate is MDI or methlyendiphenyl-isocyanate. A polyurethane form formed from MDI with a polyol may have the aforementioned viscoelastic properties.

One example of a prior art mattress is disclosed in <CIT> (Gladney, assigned to Dreamwell Ltd) which teaches a mattress comprising at least one coiled spring layer and an underlaying support layer of a viscoelastic foam in which the coiled spring layer is in direct contact with the viscoelastic form. Another example of a prior art seat base or bed support is known from US Patent No <CIT>.

It is known from the prior art that springs and foams can be connected in a serial manner. For example, US Patent <CIT>) teaches a foam encasement which surrounds an innerspring unit having a plurality of springs. The mattress construction shown in this US patent is said to improve comfort by combining the properties of the foam and the springs. This construction of combining the properties of the springs and the foam on top of each other is felt by the user. The uppermost part of the construction is mostly made of foam and is the primary contact material felt by the user and which reacts initially under load of the user. The secondary material is below (and is mostly springs) and only reacts once the foam transfers the load of the user due to the body weight further downwards. This means that the foam is already partly compressed. The foam and the springs in this construction can move independently from each other and are not attached to each other.

Another example is disclosed in <CIT>). This patent application teaches a pocket coil-spring assembly that includes an amount of flexible foam positioned in an interior cavity of the coil-spring and having a top surface that extends above the coil spring. There is no mention in this application of a connection between coil and spring. The figures show only that the coil-spring and the flexible foam touch each other at certain sections. The property of this construction to combine the flexible foam and the coil-spring is that the foam section reacts first under load as the flexible foam extends above the coil-spring and so the flexible foam is the primary factor for the comfort feeling of the user. This effect is wanted by the inventor as detailed in that document.

The spring and the foam are not connected to each other and so they can move independently from each other without being synchronized. By adding a pocket material made from inflexible material as described in the patent application, this pocket material will disturb the dynamic reaction to the load negatively as the pocket material is an inflexible material which will become 'loose' under the load, without any dynamic reflection. The combination of the flexible foam and the coil-spring as shown in <FIG> of that document also shows no connection to synchronize the behavior of the coil spring and the flexible foam under dynamic load. The coil-spring and the flexible foam can move independently from each other especially when under low load. The patent document recommends that the flexible foam should fill all of the interior space within the coil-spring and so the flexible foam will expand under load outwards between the metal wire from which the coil spring is made. This expansion will change the behavior of the spring completely, as the flexible foam restricts and stops the movement of the coil-spring, becoming very firm itself. A combination of foam and spring under load with the foam squeezed between the wire shows no 'spring' or `flexible foam' feel but is just very firm and static without any dynamic response.

<CIT>) describes a mattress without springs but a channel in the base section which - in connection with a fan - is said to provide cooling.

Dutch Patent <CIT>) teaches an interior mattress with a large number of wire springs axially extending between the mattress top and the bottom of the mattress formed with wire and elastic material with the elastic material to extend over at least the major part of the axial wire spring length. This patent application fails to describe any attachment (i.e. bonding, adhesion, or other firm connection) of the foam and the spring components.

As known from the prior art patent application <CIT> the extension of the elastic material above the spring will lead to this elastic material section to react first and primarily to the load of a user of such a product in the Dutch Patent. There is no attachment between the spring and the elastic material, the spring and the elastic material only touch each other at various points, which might be at different points under load or not under load. This construction leads to the spring and the elatstic material being able to move independently from each other under dynamic load. So, the elastic material could move up at a faster rate under pressure release, reducing any comfort effect of the spring which might expand at a slower rate. Furthermore, in this prior art document, the elastic material is shown to fill up mostly all space within the spring. This will lead the elastic material being able to extend between the wires of the springs, as described earlier.

Canadian Patent <CIT>) describes a spring consisting of a spring wire helix and a core of spongy elastic material inserted in and extending substantially the full height or length of the spring wire helix with the core `snugly fitting' when the spring is not loaded, but extending between the wires once the spring is under load. There is no description of any attachment between the spring and the spongy elastic material. In a manner, similar to the disclosure in the patent application <CIT> and <CIT>, this type of construction will not synchronize the effects of the elastic material and the spring as they can move independently from each other. In this case the fact that the elastic material is supposed to squeeze out between the wire of the spring will lead to a static - non responsive - behavior of this construction under full load.

Furthermore, similar to the patent application <CIT>, the UK patent application <CIT> (Price Bros) also describes a composite spring comprising a coil spring coaxially enclosing a deformable core, at least some of the coils of the spring being in contact with the periphery of the core and deforming the surface of the core. As can be seen clearly from the figures in this patent application, the foam in the deformable core squeezes out between the wire of the spring under load, which is the 'deformed surface'. The disadvantages of such a combination of the spring and the foam as described in this patent application is outlined in the above paragraphs.

The analysis of the prior art can be summarized that the different dynamic parameters of each of the materials, i.e. foam and spring, to react under load due to the user was noted. As the foam material in the prior art disclosure is mostly positioned on top of or extending above the spring section, the `foam feeling' dominates the overall dynamic response of those combinations. The static behavior of a fully loaded combination of spring and foam with the foam creeping out between the wire of the spring was obviously accepted or even welcomed in prior art.

Based on the aforementioned prior art, the object of the present invention is to improve the comfort of the shaped body for the user.

The invention provides a shaped body as claimed in claim <NUM>. The shaped body comprises at least one spring and at least one foam section. The uppermost section of the foam section is attached to the uppermost section of the at least one spring, and the lowest section of the foam section is attached to the lowest section of the least one spring. The uppermost section and the lowest section are attached by affixation through a top plate and a bottom plate to the at least one spring. The top plate (<NUM>) and/or bottom plate (<NUM>) could be made of metal or another plastic and must be sufficiently mechanically firm to generate parallel behavior. In other words, the foam section and the spring are attached in at least two places in a parallel fashion so that the shaped body acts as a single object on compression. The firm connections can either be made directly in which sections of the foam are attached directly to the spring, or through an intermediate element, such as a plate or similar firm material. The shaped body with the parallelly organized spring and foam section has effectively properties similar to that of a viscoelastic foam, i.e. it is both viscous being resistant to shear or strain when subjected to a force and being elastic and returning to its original shape on removal of the force.

During use as a mattress the pressures applied by the sleeper on an upper surface of the mattress are very different at different times, as the body weight of the sleeper is not distributed evenly over the upper surface of the mattress. Large surface areas pressured by the body of the sleeper are subject to only <NUM> - <NUM> kPa - for example, at the areas where legs, arms or the lordosis of the sleeper are located. Pressure in the hip or shoulder areas are mostly <NUM>-<NUM> to <NUM> kPa but can easily reach peak values at <NUM> to <NUM> kPa. These peak values are only affecting a rather small area of the body touching the upper surface of the mattress, these peak values determine the comfort feeling significantly of the mattress for the sleeper. It is these areas (shoulder and hip zone) that determine if the mattress is perceived as soft, firm or otherwise responsive, because these areas carry the largest percentage of body weight of the sleeper. So, if the foam section is designed such that the foam section is unable to squeeze out between the wire coils forming the spring, the foam section should not do so even if the shaped body is subject to forces between <NUM> to <NUM> kPa. , when the sleeper is lying on the shaped body forming the mattress.

In one aspect, there is no need to use a viscoelastic foam in the shaped body. The viscoelastic foam would be affected by temperature and could even change its properties unpredictably with the presence of body heat. The viscoelastic foams are also impermeable to air and create therefore a feeling of heat or warmth which may be uncomfortable to a person sitting on a cushion or lying on a mattress. Furthermore, viscoelastic foams are more expensive than conventional foams.

In another aspect, it is possible to also use a viscoelastic foam in the shaped body and this will enable adjustment of the viscoelastic properties of the foam.

The shaped body can be used in a cushion for example on a chair, or as a mattress for a bed. It will be appreciated that these applications are, however, not limiting of the invention.

In one aspect, the foam section is positioned inside the spring. This protects the foam section from damage.

A temperature-regulating device is arranged in thermal contact with the at least one section of the foam section having thermoelastic properties; and a control device for the temperature-regulating device adapted to adjust the firmness of the foam section by alteration of temperature. This enables the firmness of at least part of the foam to be adjusted.

The shaped body with the thermoelastic foam section can have at least one of a horizontal channel or a vertical channel to enable air to circulate within the shaped body and cool the shaped body.

The shaped body with the thermoelastic foam section may also include a plurality of sensors to measure pressure applied to a surface of the shaped body.

In one aspect the spring comprises an inner section which is located completely within the spring and contains a foam section. The uppermost and lowest parts of the foam section and the spring are attached to each other and the foam section is designed to have a cross diameter sufficient smaller than the cross section of the spring, so that the foam will not creep or extend between the wire of the spring under load of maximum <NUM> N/cm<NUM>.

The invention will now be described on the basis of the drawings. It will be understood that the embodiments and aspects of the invention described herein are only examples and do not limit the protective scope of the claims in any way. The invention is defined by the claims and their equivalents. It will be understood that features of one aspect or embodiment of the invention can be combined with a feature of a different aspect or aspects and/or embodiments of the invention.

The present document teaches a shaped body <NUM> which comprises at least one spring <NUM> having an inner section <NUM> and one foam section <NUM> as is shown in <FIG> and is suitable, for example, for use as a mattress for a bed or a cushion. The foam section <NUM> is either a conventional polyurethane foam or can be made from a viscoelastic foam, but this is not limiting the invention and other types of foam can be used in the shaped body. The viscoelastic foam has the property that it changes its dynamic properties on warming, as will be explained below. The conventional polyurethane foam does not change its dynamic properties on warming at typical room temperatures. It will be seen in <FIG> that the cross diameter of the foam section <NUM> is smaller than the cross-section of the inner section <NUM> of the spring <NUM>.

The shaped body can be used in connection with a warming device, sensors and a controller to change the properties of the foam in the mattress or cushion, as explained below. This enables the use of such shaped bodies in areas which are close to surface of a product, such as in the mattress on the bed. The shaped bodies enable significant changes in the firmness of the bed and its mattress, which are substantially independent of the influence of body temperature on their firmness. This means that the foams can be placed close to the surface of the mattress of the bed, and therefore the changes in firmness are more perceptible during the use of the bed.

The thermoelastic foams together with a temperature changing device enabling the warming of the foams in the range from <NUM>° C to <NUM> and results in the product having changing properties. The inventors have established that the changes in the firmness of the foam itself are rapid and can be clearly noticed by the user, even with small changes in the temperature caused by the temperature changing device.

The combination of the spring <NUM> and the foam <NUM> described in this document behaves differently to the combinations described in the prior art. The forces of increasing load will reach the spring <NUM> and the foam <NUM> at the same time and will keep this synchrony all the way until both the spring <NUM> and the foam <NUM> are substantially completely compressed. Furthermore, the forces released by this combination of the spring <NUM> and the foam <NUM> under decreasing load towards the user will come from both the spring <NUM> and the foam <NUM> at the same time and keep this synchrony all the way until both the spring <NUM> and the foam <NUM> are fully expanded.

In the known prior art one of the components of either the spring <NUM> or the foam <NUM> is found to dominate the response to increasing or decreasing load at the beginning or at any time during compression and expansion, because the spring <NUM> and the foam <NUM> of the prior art can move independently from each other and the 'firmer' part will dominate under compression and the part with the higher recovery force will dominate under expansion. The only 'harmonized' reaction of both components in the prior art is the phase during which the foam is creeping or extending between the wire of the spring. This creeping out leads to a static non-responsive reaction of such a combination, as the two materials, i.e. the foam and the springs are blocking each other, and this blocking is unwanted.

The expression 'uppermost' or 'lowest' section of a spring or the foam is defined as the sections within this foam/spring combination. This combination can be glued to foam or spring on top or below this combination within a final product.

A shown in the example of <FIG>, an uppermost section <NUM> and a lowest section <NUM> of the foam <NUM> are attached to the springs <NUM> as this will enable the foam <NUM> to return to the original shape after removal of a load. The construction can include channels or holes in the foam <NUM> or elsewhere to allow warmer air to leave the section of the foam, based on the tendency of warmer air to rise.

As noted above, the shaped bodies with comfort features are made of the foam <NUM> with the springs <NUM>. These springs <NUM> are mostly metal, although some plastic versions are available. The springs <NUM> are either attached to each other or are standing singly in pockets beside each other, as can be seen in <FIG>. The springs <NUM> can be assembled in several layers horizontally placed on top of each other. In this latter case of several horizontal layers, each one of the horizontal layers may have a different firmness characteristic with the uppermost horizontal layer of the springs <NUM> being the softest one of the layers and the lowermost horizontal layer being the firmest one of the layers. This leads to an increase of the firmness with increased load forces from the top of the product during use.

The springs <NUM> and the foam <NUM> have different firmness characteristics, which can be demonstrated by examining the load deflection curve, as shown in <FIG> are graphs in which increasing flexural loads on a beam are plotted along the vertical axis, and deflections resulting from these loads are plotted along the horizontal axis. Both curves are distinctively different for foam and for springs. <FIG> shows the graph for one of the springs <NUM>. It will be seen that the increase of firmness with increasing is very linear, but not in the beginning with a low load.

The same curve for polyurethane flexible foam is seen in <FIG> and has a different characteristic. As can be seen the increasing load for the polyurethane flexible foam <NUM> leads to an increasing firmness at a low load, then the firmness is more or less static with an increasing load, before increasing fast again when the polyurethane foam is compressed completely.

As noted in the introduction, there have been different trials in the past to combine both comfort materials into one product, to form so called hybrid products. It was found that placing both materials (i.e. the springs plus the polyurethane foams in a serial manner) in one product does not lead to a positive combination of both deflection curves, as each of the two different materials keeps its own firmness characteristics.

It had been found that one combination of both materials is the integration of the polyurethane foam <NUM> into the spring <NUM> with a mechanical firm connection of the uppermost section <NUM> of the polyurethane foam <NUM> to the uppermost section <NUM> of the springs <NUM> and the lowest section <NUM> of the polyurethane foam <NUM> with the lowest section <NUM> of the spring <NUM>. This attachment can be made, for example, by means of an adhesive. This combination was found to generate an unexpected behavior of the final product as the combination behaves like an ordinary spring but with a very linear increase of firmness from low to high, until the two materials (both the polyurethane foam <NUM> and the spring <NUM>) are compressed completely. The polyurethane foam <NUM> dampens the movement of the spring <NUM> but the overall combination maintains its resilience as a spring, unless compressed completely. The foam <NUM> can be sized in a way that the foam <NUM> does not creep out from between the wire material under load of the spring <NUM>, as this creeping out would destroy the dynamic properties of the combination of the foam <NUM> and the spring <NUM> described herein. For example, this condition can be fulfilled by designing the section of the flexible foam <NUM> to be sufficiently smaller in diameter than the diameter of the spring <NUM>.

Using a thermoelastic foam with a corresponding controller to control the firmness together with the spring <NUM> enables controlling of the firmness of the shaped body <NUM> by controlling the firmness of the thermoelastic foam <NUM>. With the air on both side of the thermoelastic foam <NUM> inside the spring <NUM>, a fast release of excessive thermal energy is possible.

It was also found that it is not necessary to connect all the springs <NUM> to the polyurethane foam <NUM>. It was found that if one or more of the springs <NUM> are mechanically connected to the modified spring <NUM> (with the polyurethane foam), this will lead to those adjacent ones of the springs <NUM> (without the attachment to the polyurethane foam) to react to the increasing load in a similar way. Thus, only some of the springs <NUM> in a product have to be modified to achieve the effects described.

<FIG> shows a typical construction of a section of a shaped body, such as the aforementioned bed, mattress or cushion. Several of these sections can be placed adjacent to each other, either horizontally or vertically or both to form the complete product.

The shaped body <NUM> shown in <FIG> comprises a spring <NUM> with the uppermost section <NUM> and the lowest section <NUM> which is attached to a foam <NUM> arranged inside the body of the spring <NUM>. The foam <NUM> has an uppermost section <NUM> and a lowest section <NUM> which are attached by affixation, e.g. by an adhesive, through a top plate <NUM> and a bottom plate <NUM> to the spring <NUM>. The foam <NUM> can be a viscoelastic foam as discussed in this document or a conventional foam. The top plate <NUM> could be at the surface of the mattress and the bottom plate <NUM> could be at the bottom surface of the mattress or cushion. It is also possible that the top plate <NUM> and the bottom plate <NUM> are intermediate layers within the mattress or cushion as long as the top plate <NUM> and the bottom plate <NUM> attaches spring <NUM> and foam <NUM> with each other. The top plate <NUM> and/or the bottom plate <NUM> must therefore be sufficiently mechanically firm to generate parallel behavior and could be made of metal or another plastic.

<FIG> shows an alternative construction of the shaped body <NUM> in which the spring <NUM> is arranged inside a cylindrically shaped foam <NUM>. The uppermost section <NUM> of the spring <NUM> is attached to the upper section <NUM> of the foam <NUM> and the lowest section <NUM> of the spring <NUM> is attached to the lowest section <NUM> of the foam <NUM>. In this combination the foam <NUM> will move outwards under increasing load so that the foam <NUM> is not creeping out from between the wire of spring <NUM>.

<FIG> shows a plurality of metal springs <NUM> are arranged adjacently along the length of a block shaped piece of the foam <NUM>. This construction could be used, for example, in the aforementioned mattress.

Claim 1:
A shaped body (<NUM>) comprising at least one spring (<NUM>) and at least one foam section (<NUM>), whereas an uppermost section (<NUM>) of the foam section (<NUM>) is attached to an uppermost section (<NUM>) of the at least one spring (<NUM>), and a lowest section (<NUM>) of the foam section (<NUM>) is attached to the lowest section (<NUM>) of the at least one spring (<NUM>) wherein,
the uppermost section (<NUM>) and the lowest section (<NUM>) are attached by affixation through a top plate (<NUM>) and a bottom plate (<NUM>) to the at least one spring (<NUM>), said top plate (<NUM>) and/or bottom plate (<NUM>) could be made of metal or another plastic and must be sufficiently mechanically firm to generate parallel behavior.