GB2503887A

GB2503887A - A bed assembly with a dynamic mattress and a sprung base.

Info

Publication number: GB2503887A
Application number: GB201212208A
Authority: GB
Inventors: Gary Baker; Richard Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-07-10
Filing date: 2012-07-10
Publication date: 2014-01-15
Also published as: GB201212208D0

Abstract

A bed assembly comprising a sprung base 6 and a dynamic mattress 8 supported on the base 6. Also disclosed is a method involving selecting a base 6 and a dynamic mattress 8 from a plurality of choices based on a users need. The base 6 may have pocket springs 28 which are between 5.5 and 15 cm. The dynamic mattress 8 may have two layers of cells 42 and 44 with the bottom ones 42 being at a constant pressure as static cells and the top ones 44 being periodically inflated in alternating groups. The cells 42 and 44 may be cylindrical with each laying have between 25 and 40 which are less than 10cm thick. The dynamic mattress 8 may have a memory foam layer 62 made of polyurethane. A pair of dynamic mattresses may be positioned next to each other and joined by releasable fasteners on covers 64.

Description

A BED ASSEMBLY

The present invention relates to a bed assembly and to a method of providing the same.

Conventional bed assemblies generally comprise a mattress. Many mattresses are formed from foam. Foam mattresses find use in a wide range of applications, including domestic bed assemblies and beds for hospitals and clinics.

The mattress is typically resting on a support structure, such as a bed frame. One well known type of bed is a divan bed, comprising a mattress supported on a box spring base. Bed assemblies of this general design may vary in their construction, in turn resulting in the different assemblies offering differing degrees of support to a user. Generally, beds of this configuration are not considered to be therapeutic in nature.

Therapeutic bed assemblies are known. Their application and use is generally confined to hospitals, clinics and the like. Some therapeutic bed assemblies are known for domestic and home use. For example, an Adjustamatic® bed comprises a foam mattress supporting on wooden slats.

The bed is alleged to provide pressure relief for users. However, the user/mattress interface in such mattresses is static. As a result, the mattress conforms to the body of the user and distributes pressure between the body of the user and the surface of the mattress otherwise, known as the interface. However, the pressure applied to the user does not change.

Consequently, the pressure applied to the capillaries and skin tissue of the subject causes the capillaries to partially or wholly occlude. Capillary occlusion reduces blood flow and, therefore, reduces the rate at which the capillaries are replenished with fresh oxygenated and nutrient rich blood and the rate of removal of waste toxins from the capillaries. This action is vital to the health of the skin tissue. As a consequence of the effects of this applied pressure, the brain of the user instructs the body to reposition itself in a constant process, causing the user to move between lying on their back, their left side, their back again, their right side and occasionally sleeping on their front. This action disturbs the sleep pattern and that of any partner present in the bed and can result in awaking with a feeling of being tired, restless and sometimes in pain. Those users that cannot reposition themselves due to mobility or medication and who sleep on a static mattress require manual repositioning by a clinician or other person at regular intervals.

One design of therapeutic bed assembly is disclosed in US 2010/0306924. There is described and shown an inflatable mattress for a bed, the mattress being operable to provide a range of therapies. The mattress is of a complex construction, formed from many different components, necessary to provide the range of therapies. In particular, the mattress comprises one or more inflatable bladders, on which lies a plurality of laterally extending, inflatable tubes. The tubes are typically inflated under the control of a person other than the user of the mattress. One or more layers of foam are provided on the upper surface of the inflatable tubes.

Therapeutic mattresses, often referred to in the art as dynamic mattresses' are also known in the art. Dynamic mattresses are used in the care of patients confined to bed, in particular for the prevention of bed sores and ulcers. They find use almost exclusively in hospitals, clinics and the like, where they are used in conjunction with medical bed assemblies. The mattresses are operated to provide movement to the interface between the user and the mattress, thereby reducing the formation of bed sores and ulcers. However, such movement can result in the user experiencing a form of motion sickness.

A mattress of this type is described and shown in GB 2,458,892 and comprises a plurality of laterally extending air-filled tubes or chambers. A compressor for providing air to the tubes is provided and is operated to inflate and deflate the tubes independently in a predetermined pattern over time.

Again, in use, the compressor of a mattress of this kind is generally operated by a person other than the user of the mattress. The compressor is typically located at the foot of the bed, out of reach of the person lying on the mattress.

An early design of dynamic mattress is described and shown in GB 1,595,417 and comprises two layers of laterally extending chambers or tubes, separated by a shaped layer of foam.

GB 2,197,192 discloses an alternating pressure pad having two or more layers of cells. The cells of each layer are inflatable independently of the cells in the other layer. The cells in one layer of the pad overlie the cells in another layer of the pad.

GB 2,327,874 discloses an inflatable support, in particular a low air loss mattress having an upper layer of inflatable cells and a lower layer of cells. In use, the lower layer of cells is maintained at a constant pressure, higher than the pressure in the upper layer of cells. In this way, the person lying on the mattress is prevented from contacting the underlying supporting surface, in particular when sitting on the mattress or when being moved. The cells in the upper layer may be inflated to different pressures, to provide differential support to different parts of the person. As above, operation and control of the inflatable support in practice is typically by a person other than the user of the support, such as a clinician or nurse.

A mattress having a plurality of transverse air-filled chambers or cells is also disclosed in each of US 2008/0095322 and EP 2 465 480.

A mattress comprising two layers of inflatable cells on a foam base is described and shown in GB 2,473,661.

In general, couples in which one person is disabled or movement-impaired and the other is able bodied have a difficult choice for the bed assembly. In many cases, due to the specific and very different needs in the bed assembly, the disabled or movement-impaired person sleeps on a dynamic mattress, as described above, and apart from the other person, who uses a standard, static mattress. The alternative is generally for the disabled or movement-impaired person to forego the advantages of a dynamic mattress and to use the shared static mattress.

An improved bed assembly has now been identified, that provides the significant therapeutic advantages of a dynamic mattress, while being practical and cost effective for use in a wider range of applications and situations than existing dynamic mattresses. In particular, a bed assembly has been found which may be used by ill, including critically ill, persons while sleeping with their partners, who may be able bodied.

In a first aspect, the present invention provides a bed assembly comprising: a sprung base; and a mattress; wherein the mattress is supported on the sprung base, the mattress being a dynamic mattress.

In the present specification, the term dynamic mattress' is a reference to a mattress having a plurality of inflatable cells, preferably laterally extending cells, for containing air under pressure. The dynamic mattress is typically provided with air at elevated pressure by a compressor under the action of a controller. In use, the cells of the dynamic mattress are inflated and deflated in a pattern determined by the controller, thereby changing the pressure applied to the body of a patient lying on the mattress. In this way, the need for manual repositioning of the patient is reduced and can even be eliminated.

Further, this arrangement can significantly reduce repositioning regimes and therefore reduced the occurrence of disturbed sleep for the user. Still further, the increase and decrease in pressure in the cells stimulates the capillaries of the user, in turn removing toxins from the tissue, increasing the blood flow to the tissue and replenishing the tissue with nutrients and oxygen. These effects reduce the formation of sores and ulcers on the patient, in particular in the case of the long term sick and bedridden, and increase the rate of healing of any sores and ulcers formed.

A problem with known dynamic mattresses is that the movement caused by operation of the mattress, as described above, can induce a form of motion sickness in the patient. In many cases, the mattress is operated by a second person. Further, known dynamic mattresses are for a single person, preventing them from being used in a double bed by a couple, one or both of whom require the effects of a dynamic mattress.

It has been found that a bed assembly comprising a dynamic mattress supported on a sprung base is particularly advantageous. The assembly is readily manufactured and supplied in large numbers, as is required for example by any bed assembly for the domestic market. The bed assembly provides the therapeutic advantages of a dynamic mattress. However, these advantages of the dynamic mattress are combined with the practical advantages offered by the sprung base. In particular, the bed assembly of the present invention offers significant advantages for beds used by two persons, arrangements of which are described in more detail below. The interaction of the dynamic mattress and the sprung base allow each person to optimise the operation of the dynamic mattress to their needs, while leaving the other person undisturbed.

The bed assembly of the present invention comprises a sprung base.

The base supports the dynamic mattress. References herein to a sprung base' are to a base that underlies the dynamic mattress and provides support thereto, and that comprise a resilient spring assembly able to yield under the weight and movement of users of the bed assembly. Suitable resilient spring assemblies for use in the base are known in the art.

In one preferred embodiment, the sprung base comprises a plurality of independent spring modules, that is each spring assembly is responsive to a force or weight applied to the sprung base while having little or no effect on the adjacent or more distant spring modules of the base. Each spring module comprises one or more springs. Suitable forms of springs for use in the sprung base are known in the art.

In one particularly preferred embodiment, the sprung base comprises a plurality of pocket spring assemblies. A pocket spring assembly comprises a spring, in particular a coil spring, retained within a flexible support or housing, in particular a generally cylindrical pocket formed from fabric. Such pocket spring assemblies are well known in the art. The pocket spring assemblies are arranged adjacent one another, typically within an outer cover, with the coil springs extending with their longitudinal axes vertical and substantially parallel. In use, the pocket spring assemblies each act in response to a weight or force applied to the base substantially independently of the adjacent assemblies. In this way, a force or weight applied to one portion of the dynamic mattress and/or the sprung base gives rise to movement in the pocket springs underlying the one portion and to little or no movement in adjacent or more distant pocket springs.

The pocket spring assemblies may be of any suitable length.

Preferably, the pocket spring assemblies are from 2.5 to 25.0 cm in length, more preferably from 5.0 to 20.0 cm in length, still more preferably from 7.5 to 15.0 cm in length. One particularly preferred length is about 10.0 cm Typically, the base rests on the floor, either directly or indirectly through one or more legs, feet or wheels, such as castors. In one embodiment, the sprung base comprises a support assembly, the support assembly providing support for the spring assembly. The support assembly may have any suitable structure. In one embodiment, the support assembly comprises a frame for supporting the spring assembly above the floor or ground. The support assembly may comprise space for storage. In one preferred embodiment, the support assembly comprises one or more drawers.

The bed assembly of the present invention further comprises a dynamic mattress overlying the sprung base. As noted above, the dynamic mattress comprises one or more layers of cells, each cell being inflatable with a gas, in particular air. In a preferred arrangement, the cells extend laterally, that is across the dynamic mattress. Such dynamic mattresses are known in the art and are commercially available. The dynamic mattress may comprise one or a plurality of layers of inflatable cells.

In one preferred embodiment, the dynamic mattress comprises a first layer of inflated cells. The first layer of cells extends across the upper surface of the base layer, with the mattress in use. The cells in the first layer extend transversely, that is laterally across the mattress, substantially perpendicular to the longitudinal axis of the mattress. The cells may have any suitable shape and form. Preferably, the cells are generally cylindrical. The cells are formed with a cell wall of flexible, gas-impermeable material. Suitable materials are known in the art and are commercially available. Preferred materials for forming the cell wall include known polymers, in particular polyurethane.

In use, the cells of the first layer are inflated to a first pressure with gas.

The cells are preferably maintained at a substantially constant gas pressure during use. Accordingly, the cells in the first layer may be referred to as static cells'. Preferably, the gas within the cells of the first layer is kept at a constant, predetermined pressure. It is preferred that all the cells of the first layer are filled with gas to substantially the same pressure. The pressure of gas within the cells of the first layer is selected to provide the required level of support to the patient, when the mattress is in use. Preferably, the pressure of gas within the cells of the first layer is in the range of from 20 to 80 mmHg, more preferably from 25 to 70 mmHg, still more preferably from 30 to 60 mmHg. A minimum gas pressure of 25 mmHg, more preferably 30 mmHg, has been found to be suitable for providing the required level of support to a patient lying on the mattress for a prolonged period of time.

The pressure of gas within the cells of the first layer may be varied, according to the size and weight of the patient using the mattress. It is preferred that all cells in the first layer are maintained at substantially the same gas pressure. However, should it be required, the first layer may be divided into two or more regions, each region comprising one or more cells, the gas pressure within the cells varying from region to region. It is particularly preferred that the gas pressure within the cells of the first layer is constant.

The dimensions of the cells of the first layer will be determined by such factors as the structure and form of the other layers of the bed assembly and the level of support required for a person lying on the bed. The cells of the first layer extend laterally across the base, as noted above. The cells of the first layer may have any suitable dimensions, in particular to provide the layer of first cells with any suitable or desired thickness. Typically, the cells of a dynamic mattress are up to 10.0 cm in thickness, that is for a cylindrical cell 10.0 cm in diameter. However, as noted above, one problem with dynamic mattresses can be inducing motion sickness in users. It has been found that one reason for this motion sickness arising is the large diameter of the inflatable cells. The larger cell diameters, that is of about 10.0 cm, give rise to a greater depth and range of movement of the patient, in turn inducing motion sickness. Accordingly, it is preferred that the cells of the dynamic mattress of the bed assembly of the present invention are sized to provide the first layer of cells at thickness of less than 10.0 cm, more preferably less than 8.0 cm.

Preferably, the cells of the first layer have the relevant dimension (for example a diameter in the case of the preferred cylindrical cells) to provide the first layer with a thickness of from 1.0 to 6.0 cm, more preferably from 1.5 to 5.5 cm, still more preferably from 2.0 to 5.0 cm. A preferred thickness of the first layer of cells is from 2.5 to 5.0 cm, preferably about 4.75 cm.

As noted above, the cells are prepared from a suitable gas-impermeable material. The thickness of the cell wall is selected according to the material of construction to provide sufficient strength to the cell wall to resist the internal gas pressure and retain the shape and form of the cell when the mattress is in use. A typical thickness of the cell wall is from 0.2 to 1.0 mm, more preferably from 0.25 to 0.6 mm, still more preferably from 0.3 to 0.5 mm. A wall thickness of about 0.35 mm has been found particularly suitable for cylindrical cells formed from polyurethane and having a diameter of about 4.75 cm.

The cells of the first layer are preferably of a uniform shape and size.

However, if desired, the first layer may be provided with cells of different shapes and sizes, so as to accommodate the needs of the patient.

Preferably, each cell of the first layer extends laterally across the entire width of the base and the mattress.

As noted, the cells of the first layer extend transversely across the base of the mattress. Preferably, the cells in the first layer are arranged so as to provide a continuous layer, that is adjacent cells in the layer are touching or abut each other.

The number of cells in the first layer will be determined by the overall length of the mattress and the dimensions of the cells in the layer. For example, a dynamic mattress of length 200 cm may comprise 20 cells having a diameter of 10.0 cm. Preferably, the individual cells and the mattress are sized to provide the first layer with greater than 20 cells, more particularly at least 25 cells, in particular from 25 to 40 cells, more preferably from 25 to 35 cells. It has been found that providing the first layer with from 28 to 35 cells is a particularly effective arrangement.

Any suitable gas may be used to inflate the cells of the first layer. Air is a most suitable and convenient gas. The bed assembly may be provided with means to provide gas to the cells of the first layer, in order to provide the required pressure of gas and/or to change the gas pressure within the cells, as required. Suitable means, such as pumps and compressors, for providing the gas are known in the art and are commercially available. Preferably, the pumps and/or compressors are operated under the action of a controller. The pumps, compressors and/or controller are preferably stored within the sprung base of the bed assembly, in particular within the storage space provided by a support assembly of the sprung base, as noted above. The controller for activating the pump or compressor of the dynamic mattress may be programmed with one or more desired patterns of inflation/deflation of the cells and operate automatically, and/or the controller may be controlled, preferably by the user. To this end, the controller is controlled remotely, in particular by a user lying on the mattress, for example using a wireless or wired remote control system.

The dynamic mattress may comprise a single layer of cells, having the properties hereinbefore described. More preferably, the dynamic mattress comprises a first layer of cells, as noted above and a second layer of cells. In this embodiment, the first layer of cells is arranged lowermost, in particular to overlie the sprung base, with the second layer of cells overlying the first layer of cells. In embodiments in which the dynamic mattress comprises a first and a second layer of cells, the first layer of cells, that is the layer adjacent the base, is most preferably a static layer, that is the cells are inflated to a sufficient pressure to provide support for the user lying on the mattress and the pressure in the cells is maintained substantially constant. The cells in the second layer are dynamic cells, undergoing a pattern of inflation and deflation, as described in more detail below.

The second layer of cells extends across the upper surface of the first layer of cells, with the mattress in use. The cells in the second layer preferably extend parallel to the cells in the first layer and transversely, that is laterally across the mattress, substantially perpendicular to the longitudinal axis of the mattress. The cells may have any suitable shape and form.

Preferably, the cells are generally cylindrical. The cells are formed with a cell wall of flexible, gas-impermeable material. Suitable materials are known in the art and are commercially available. Preferred materials for forming the cell wall include known polymers, in particular polyurethane.

The cells of the second layer are inflated to a second pressure with gas. The cells in the second layer are preferably divided into a first region and a second region. The cells in the first region are provided with perforations in the cell wall, such that gas may leave the cell. In this way, the pressure of gas within the cells may be varied. Gas is provided to the cell from the gas supply means to replace the gas leaving through the perforated cell wall, thereby maintaining the gas pressure within the cell. Such perforated cells are known in the art. The cells in the second region are preferably maintained at a substantially constant gas pressure during use, that is the cells of the second region are static cells. It is preferred that all the cells of the second region are filled with gas to substantially the same pressure.

The pressure of gas within the cells of the first region is selected, together with the gas pressure within the cells of the first layer, to provide the required level of support to the patient, when the bed assembly is in use.

Preferably, the pressure of gas within the cells of the first region is in the range of from 20 to 80 mmHg, more preferably from 25 to 70 mmHg, still more preferably from 30 to 60 mmHg. A minimum gas pressure of 25 mmHg, more preferably 30 mmHg, has been found to be suitable for providing the required level of support to a patient lying on the mattress for a prolonged period of time.

The pressure of gas within the cells of the first region of the second layer may be varied, according to the size and weight of the patient using the mattress. It is preferred that all cells in the first region are maintained at substantially the same gas pressure. However, should it be required, the first region may be divided into two or more portions, each portion comprising one or more cells, the gas pressure within the cells varying from portion to portion.

In use, gas is supplied under pressure to each cell in the first region, with gas being allowed to escape from the cell through the perforations at a rate determined by the size of the perforation and the gas pressure. Such an operation is known in the art.

The second layer further comprises a second region containing cells.

The cells of the second region are static cells, that is the cell wall is not perforated and the pressure of gas within the cells of the second region is maintained constant.

The pressure of gas within the cells of the second region is selected, together with the gas pressure within the cells of the first layer, to provide the required level of support to the patient, when the mattress is in use.

Preferably, the pressure of gas within the cells of the second region is in the range of from 20 to 80 mmHg, more preferably from 25 to 70 mmHg, still more preferably from 30 to 60 mmHg. A minimum gas pressure of 25 mmHg, more preferably 30 mmHg, has been found to be suitable for providing the required level of support to a patient lying on the mattress for a prolonged period of time.

The pressure of gas within the cells of the second region of the second layer may be varied, according to the size and weight of the patient using the mattress. It is preferred that all cells in the first region are maintained at substantially the same gas pressure. However, should it be required, the second region may be divided into two or more portions, each portion comprising one or more cells, the gas pressure within the cells varying from portion to portion.

In one preferred embodiment, the pressure of gas in some or all of the cells of the second layer is varied over time. In particular, it is preferred that the cells are repeatedly inflated and deflated over time. Any suitable pattern of inflation and deflation may be employed, while ensuring that the subject lying on the mattress has sufficient support. One particularly preferred arrangement is to divide the cells of the second layer into two groups, X and Y, along the length of the mattress, with the cells from group X alternating with cells from group Y in the second layer. A particularly preferred alternating pattern of cells in groups X and Y is XYXYXY. The groups X and Y preferably have substantially the same number of cells therein. The cells in group X are inflated and deflated over time, according to a predetermined regime, with the cells in group Y being inflated and deflated over time using the equal but opposite regime. In particular, the cells in group X are preferably deflated and re-inflated, with the cells in group Y being held at a constant inflated pressure.

Thereafter, once the cells in group have been re-inflated, the cells in group Y undergo a similar deflation and inflation pattern, with the cells in group X held at a constant inflated pressure.

Preferably, all the cells in group X are inflated and deflated at the same time according to the same regime. In one preferred regime, the cells in group X are deflated and held in the deflated state for a period of time, in particular from 1 to 5 minutes, more preferably from 2 to 4 minutes, especially about 3 minutes. During this inflation/deflation of cells in group X, the cells in group Y are held at constant pressure. Thereafter the cells in group X are inflated and all cells in the second layer held inflated for a period of time, in particular from 0.5 to 5 minutes, more preferably from 0.5 to 3 minutes, especially about 1 minute. The inflation and deflation of the cells depends upon the volume of the cell and the pressure of the gas supply. Typically, inflation and deflation times are from 15 to 60 seconds, more preferably from to 40 seconds, especially about 30 seconds. While keeping the cells in group X at a constant pressure, the cells in group Y are then inflated and deflated according to the same regime as those for group X. The regime is then repeated. This alternating pattern of inflation and deflation has been found to assist patients, in particular avoiding the occurrence of conditions, such as sores and the like, that arise from prolonged periods of time in bed.

All cells in the second layer may be subjected to the inflation/deflation regime described above, that is the groups of cells X and Y may extend the entire length of the mattress. In one preferred embodiment, the cells at each end of the mattress, for example from 2 to 7, more preferably 5 cells at each end, are kept constantly inflated and are not subjected to the inflation/deflation regime.

It is preferred that the cells in the region underlying the head of a user lying on the mattress do not undergo a deflation/inflation cycle, as described above.

The above deflation/inflation cycles maintains the level of comfort of the user and avoids motion sickness being induced.

The dimensions of the cells of the second layer will be determined by the pressure of gas within the cells and the gas pressure and dimensions of the cells of the first layer. The cells of the second layer extend laterally across the base. The cells of the second layer may have any suitable dimensions, in particular to provide the layer of second cells with any suitable or desired thickness. The dimensions of the cells of the second layer are as described above with respect to the cells of the first layer.

Preferably, the cells in the first and second layers have the same dimensions.

As noted above, the cells of the second layer are prepared from a suitable gas-impermeable material. The thickness of the cell wall is selected according to the material of construction to provide sufficient strength to the cell wall to resist the internal gas pressure and retain the shape and form of the cell when the mattress is in use. A typical thickness of the cell wall is from 0.2 to 1.0 mm, more preferably from 0.25 to 0.6 mm, still more preferably from 0.3 to 0.5 mm. A wall thickness of about 0.35 mm has been found particularly suitable for cylindrical cells formed from polyurethane and having a diameter of about 4.75 mm.

The cells of the second layer are preferably of a uniform shape and size. However, if desired, the second layer may be provided with cells of different shapes and sizes, so as to accommodate the needs of the patient.

Preferably, each cell of the second layer extends laterally across the entire width of the base and the mattress.

The number of cells in the second layer will be determined by the overall length of the mattress and the dimensions of the cells in the layer.

Preferably, the individual cells and the mattress are sized to provide the second layer with from 20 to 40 cells, more preferably from 25 to 35 cells. It has been found that providing the second layer with from 28 to 32 cells is a particularly effective arrangement.

It is preferred that the first and second layers contain the same number of cells.

As noted, the cells of the second layer extend transversely across the base of the mattress. Preferably, the cells in the second layer are arranged so as to provide a continuous layer, that is adjacent cells in the layer are touching or abut each other.

The cells of the second layer are preferably in direct contact with the cells of the first layer. The first and second layers preferably contain the same total number of cells, with each cell in the first layer having a corresponding cell in the second layer overlying it.

Any suitable gas may be used to inflate the cells of the second layer.

Air is a most suitable and convenient gas. The cells of a region of the second layer that are to undergo a regime of inflation and deflation are preferably provided with perforations therein, to allow air to escape from the cell. The bed assembly is preferably provided with means to provide gas to the cells of the second layer, in order to replenish the gas leaving the cells of the first region through the perforations in the walls of the cells, to provide the required pressure of gas and/or to change the gas pressure within the cells, as required. Suitable means are noted above.

The second layer may be provided with a single first region and a single second region. More preferably, the second layer is provided with a first region at each end of the dynamic mattress, with a second region of cells disposed between the two first regions. In an alternative, preferred embodiment, the second layer of the dynamic mattress is provided with a plurality of both first regions and second regions, arranged in an alternating pattern along the mattress, such as the alternating XY arrangement described above, with a first region being disposed at each end of the mattress. For example, in a dynamic mattress comprising a second layer having a total of 29 cells therein, the mattress comprises a first region at each end having 5 cells therein, a central first region having 9 cells therein and two second regions each having 5 cells disposed therebetween.

A dynamic mattress comprising a first and second layer, as described above, is a preferred embodiment. As noted above, the dynamic mattress may comprise a single layer of cells. In this case, the cells of the single layer are preferably dynamic, being formed and function as described above in respect of the second layer, that is to undergo a regime of repeated inflation and deflation.

If desired, the dynamic mattress may comprise a third or additional layers of cells, the arrangement of which may be as described above for the first and/or the second layers.

The dynamic mattress may be provided with a cover, to enclose the dynamic mattress. Suitable materials for the cover are known in the art and include polyurethane, cotton, wool, polyamides, such as nylon, rubbers, and mixtures thereof. A particularly preferred material for the cover is polyurethane.

Alternatively, or in addition to the cover, a layer of protective material, such as a fabric or foam, may be provided between the dynamic mattress and the sprung base. In this way, the cells of the dynamic mattress may be protected from the action of the sprung base, for example the action of individual pocket springs on the underside of the cells.

As described above, the bed assembly of the present invention comprises a dynamic mattress overlying a sprung base. In a preferred embodiment, the bed assembly further comprises a layer of support material, for example a foam, overlying the dynamic mattress. Suitable support materials for use in the support layer are known in the art and are commercially available. Suitable materials include polyurethane foams, in particular open-cell polyurethane foams. Other suitable materials for the support layer include natural materials, such as wool, cotton, duck and/or goose down, polymer fibres, such as nylon fibres, rubbers, such as latex rubber, and gels, including silicon gels.

In one preferred embodiment, the bed assembly comprises a layer of foam support material, in particular a layer of so-called memory foam'.

Memory foam is a visco-elastic polyurethane foam having a low resilience, that is the property of returning to its original shape after being deformed at a relatively slow rate. Suitable memory foams are known in the art and are commercially available.

The properties of the support layer, including its density, viscosity and thickness, will depend upon the requirements of the user. However, the support layer should be formed so as to ensure the effects of the dynamic mattress are passed to a patient lying on the bed assembly. In particular, the movement induced by the periodic or cyclical inflation and deflation of the cells of the dynamic mattress should be applied to the user through the support layer.

The support layer is preferably used to modulate or moderate the movement patterns of the dynamic mattress. In particular, the support material is preferably of a thickness and density so as to dissipate the interface pressure between the body of the user and the dynamic mattress evenly across the surface of the body in contact with the dynamic mattress.

Further, the support layer preferably functions to occupy voids, such as those in the lower lumbar regions of the user, that arise when lying on a mattress.

This in turn reduces pain in such regions as the lumbar region. Still further, the material of the support layer acts to occupy the spaces and voids between the cells of the uppermost layer of the dynamic mattress, thereby increasing the comfort of the dynamic mattress and further reducing the formation of sores and ulcers.

In one embodiment, the support layer is removable, in order to allow the user to remove the support layer and benefit from the full effects of the dynamic mattress without diminution or modulation, should this be required.

The layer of support material may have any suitable density. Suitable densities for foam materials may be up to 90 kg/m3, with densities up to 80 kg/rn3 being preferred. Foam densities in the range of from 15 to 80 kg/rn3 are preferred, more preferably from 25 to 75 kg/m3, still more preferably from 35 to 70 kg/m3.

The thickness of the support layer will depend upon such factors as the properties of the support material and the extent to which the action of the dynamic mattress is to be modulated. Preferably, the support layer has a thickness of from 0.5 to 10.0 cm, more preferably from 1.0 to 7.5 cm, still more preferably from 2.0 to 5.0 cm. One preferred thickness of the support layer is about 3.0 cm.

The support layer may be in direct contact with the upper surface of the dynamic mattress. Preferably, the support layer is retained within a cover, for example the aforementioned cover enveloping the dynamic mattress.

Alternatively, the support layer may be provided with and retained within a dedicated cover. Suitable materials for the cover for the support layer are as noted above.

The bed assembly of the present invention may be provided for use by a single person, that is a single bed, or for use by a plurality of persons, that is a double bed. The dimensions of single and double beds, in particular their lengths and widths, are known in the art.

In the case of a single bed embodiment, the bed assembly of the present invention comprises a single sprung base and a single dynamic mattress thereon.

In the case of a double bed embodiment, the bed assembly may similarly comprise a sprung base and a single dynamic mattress. More preferably, the bed assembly comprises a first mattress and a second mattress alongside the first mattress, the first mattress being a dynamic mattress. The second mattress may be a static mattress, for example of conventional construction. More preferably, the assembly comprises a first dynamic mattress and a second dynamic mattress, adjacent the first, both overlying the sprung base. In this way, the structure and operation of each of the first and second dynamic mattresses may be tailored to suit the needs of each of the two users of the double bed.

To retain the or each dynamic mattress in position on the sprung base, panels, preferably of a foam material, may be provided along one or more of the sides, head and foot of each dynamic mattress. Suitable foam materials for forming the retaining panels include polyurethane foams.

The or each dynamic mattress is preferably retained within a cover.

Suitable materials for use in forming the covers are known in the art and are commercially available. In embodiments comprising a first dynamic mattress and a second dynamic mattress, each mattress is preferably provided with a respective cover, the covers being joined together along the adjacent longitudinal edge of each mattress, for example by one or more zip fasteners, strips of hook and loop fasteners, studs or the like. In this way, the shape of the bed assembly is rendered more stable.

In addition, the bed assembly may be provided with a cover extending over the dynamic mattress(es), the sprung base and the foam layer, if present. Again, suitable materials for forming the cover are known in the art and are as described above.

In embodiments comprising more than one dynamic mattress on the sprung base, a single layer of support material may be provided extending across the dynamic mattresses. Alternatively, each dynamic mattress is provided with a dedicated layer of support material. This allows the properties of the support layer and the bed assembly as a whole to be tailored to the user of each dynamic mattress.

The bed assembly may be provided as a series of modular components, from which a complete bed assembly may be constructed. It is an advantage of the bed assembly of the present invention can be assembled by selection of the different components according to the needs of the user or users.

Accordingly, in a further aspect, the present invention provides a method of assembling a bed assembly for a user, the method comprising: providing a first set of components comprising a plurality of sprung bases, each sprung base comprising a resilient spring assembly, the sprung bases of the first set differing in the properties of the spring assembly; providing a second set of components comprising a plurality of dynamic mattresses, each dynamic mattress comprising a plurality of laterally extending, inflatable cells, the dynamic mattresses of the second set differing in the properties and/or form of the cells; selecting a sprung base from the first set according to the needs of the user; selecting a dynamic mattress from the second according to the needs of the user; and assembling the sprung base and the dynamic mattress into a bed assembly as hereinbefore described.

As noted above, the bed assembly of the present invention may comprise, as a further component, a layer of foam to overlie the dynamic mattress. Accordingly, in one embodiment the method further comprises providing a third set of components comprising a plurality of layers of support material, the layers of support material differing in their properties and/or form, and further assembling the layer of support material into the bed assembly.

The components of the bed assembly may be selected according to any one or more of the properties indicated above, as determined by the needs of the user. For example, the sprung base may be selected according to the overall depth of the base, the firmness of the spring assemblies, and the thickness or height of the spring assemblies. Similarly, the dynamic mattress may be selected according to the number of layers of cells, for example one layer, two layers, or more layers, the thickness of the or each layer of cells and the overall thickness of the dynamic mattress. Similarly, the support layer, if present, may selected according to such parameters as the type of material, the density of the support material, and the thickness of the support layer.

Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a bed assembly according to one embodiment of the present invention, shown with a person lying thereon; and Figure 2 is a perspective view of a bed assembly for two persons.

Turning to Figure 1, there is shown a bed assembly, generally indicated as 2, in use by a person 4 lying thereon. The bed assembly comprises a sprung base, generally indicated as 6, a dynamic mattress, generally indicated as 8, and a support layer, generally indicated as 10.

The sprung base 6 comprises a generally rectangular support base 22.

The support base 22 shown in Figure 1 is in the form of a divan base, having a frame of wood and/or metal supporting elements providing a box-like supporting structure. The support base 22 has a generally hollow interior and is rigid. One or more drawers 24 are provided in the support base. The sprung base 6 further comprises a layer of spring assemblies 26, each spring assembly being a pocket spring comprising a helical or coil spring 28 retained within a fabric cover 30. Each pocket spring 26 is about 10 cm in length, with the coil spring 28 arranged vertically, as shown in Figure 1. Each pocket spring 26 functions independently of the adjacent and distant assemblies, yielding under a load applied to the upper surface of the sprung base 6.

The sprung base 6 is provided with a removable polyurethane cover 32 extending thereover. The cover 32 separates the sprung base 6 from the overlying dynamic mattress 8. If a cover 32 is not provided, a layer of fabric is preferably disposed between the sprung base 6 and the dynamic mattress 8.

The dynamic mattress 8 comprises a first layer of inflatable cells 42 and a second layer of inflatable cells 44. Each layer 42, 44 is shown as containing 29 generally tubular cells extending laterally across the bed assembly 2. The number of cells in each layer 42, 44 may vary from the number shown. Each cell has a diameter of about 5.0 cm. The cells of each layer 42, 44 are each connected via a network of air lines 46 extending through the sprung base 6 to a compressor/controller 48 located in the drawer 24 of the base 6. The compressor/controller 48 is operable to supply the cells 42 with air at an elevated pressure to inflate the cells. Further, the compressor/controller 48 is operable to selectively inflate and deflate individual cells or regions of cells, as described hereinbefore. A wireless remote control unit 50 is provided to allow the user 4 to remotely control the operation of the controller/compressor 48.

The cells in the first layer 42 are static cells, that is in use the cells in the first layer are inflated to the required pressure and the pressure of air therein is maintained substantially constant.

The cells in the second layer 44 are dynamic cells and are subjected to a pattern of inflation and deflation cycles as described hereinbefore. The cells in the second layer 44 are arranged into a plurality of regions. In particular, the cells are arranged into alternating regions of cells X and cells Y, with the cells in each region being subjected to the same inflation/deflation cycle, again as described above.

The cells of the second layer 44 in region Z, underlying the head of the user 4, are static cells and not subject to a deflation/inflation regime.

The dynamic mattress S may be provided with a single layer of cells, in which case the cells are arranged and operated as described above with respect to the second layer 44. Alternatively, the dynamic mattress 8 may comprise three or more layers of cells, with the upper most layer having the arrangement and operation described above with respect to the second layer and the underlying layers being static layers, as described above with respect to the first layer of cells.

The dynamic mattress S is provided with retaining foam portions 52 at its ends and along its sides. The dynamic mattress is further provided with a removable polyurethane cover 54 extending thereover. The cover 54 is secured to the cover 32 of the sprung base by suitable fasteners, such as zip fasteners or the like.

The bed assembly 2 further comprises a layer of support material 10, formed from a layer of polyurethane memory foam 62 having a thickness of from 3.0 to 5.0 cm. The support material 10 is retained within a removable cover 64, which is secured to the cover 54 of the dynamic mattress S by suitable fasteners, such as zip fasteners or the like.

In use, the dynamic mattress 8 is operated as hereinbefore described, in particular to selectively inflate and deflate the cells in regions X and Y of the second layer 44, thereby inducing movement in the upper surface of the dynamic mattress. This movement is modulated by the memory foam layer 62, before transmission to the user 4. Further, the memory foam layer 62 reduces the voids formed between the body of the user and the dynamic mattress and occupies the cavities in the upper surface of the second layer 44 of cells of the dynamic mattress 8.

Movements of the user 4 applying a significant force on the dynamic mattress, such as rolling over, sitting up or sitting down on the bed assembly, are absorbed by the sprung base, the spring assemblies 26 yielding under locally applied forces, while maintaining the remaining portions of the bed assembly stable and motionless. In this way, a significant movement on one region of the bed assembly has little or no effect on other regions of the bed assembly. This is particularly advantageous when the bed assembly 2 is being used by two persons at the same time.

Turning to Figure 2, there is shown a perspective view of a bed assembly, generally indicated as 102, according to the present invention and for use by two persons. The bed assembly 102 comprises a sprung base 106 having the general structure as described above with respect to Figure 1 and of a size for a double bed. The assembly 102 further comprises a first dynamic mattress 108 and a second dynamic mattress 110, the first and second dynamic mattresses 108, 110 lying side by side on the sprung base 106. Each dynamic mattress 108, 110 has the general structure described above, with the respective compressor/controller being housed in a drawer in the sprung base, as described above.

Each dynamic mattress 108, 110 is provided with a respective cover 112, 114, with the covers being releasably attached to each other by a zip fastener 120.

The bed assembly 102 is preferably provided with a support layer, as described above and shown in Figure 1. A single support layer, retained with a cover, may be provided across both the first and second dynamic mattresses 108, 110. Alternatively, to meet the needs of each user more closely, a separate support layer and cover may be provided for each dynamic mattress.

As described above, the components of the bed assemblies 2, 102 are divided into the sprung base, separate dynamic mattresses and the support layer, each with a respective cover. As a result, the bed assembly may have its components selected to meet the needs of a specific end user, according to the general method described above.

Claims

CLAIMS1. A bed assembly comprising: a sprung base; and a mattress; wherein the mattress is supported on the sprung base, the mattress being a dynamic mattress.
2. The assembly according to claim 1, wherein the sprung base comprises a plurality of independent spring modules.
3. The assembly according to claim 2, wherein each independent spring module is a pocket spring assembly.
4. The assembly according to claim 3, wherein the pocket spring assemblies are from 7.5 to 15.0 cm in length.
5. The assembly according to claim 4, wherein the pocket spring assemblies are each about 10.0cm in length.
6. The assembly according to any preceding claim, wherein the sprung base comprises a support assembly.
7. The assembly according to claim 6, wherein the support assembly comprises one or more drawers.
8. The assembly according to any preceding claim, wherein the dynamic mattress comprises a first layer of cells overlying the sprung base and a second layer of cells overlying the first layer of cells.
9. The assembly according to claim 8, wherein the cells in the first layer are static cells, in use being held at a substantially constant pressure, and the cells of the second layer are subjected to a regime of periodic inflation and deflation.
10. The assembly according to any preceding claim, wherein the cells in the region of the dynamic mattress underlying the head of the user, when in use, are maintained at a substantially constant pressure.
11. The assembly according any preceding claim, wherein the dynamic mattress comprises a plurality of laterally extending inflatable cells.
12. The assembly according to claim 11, wherein the cells are generally cylindrical.
13. The assembly according to either of claims 11 or 12, wherein the or each layer of cells comprises from 25 to 40 cells.
14. The assembly according to claim 13, wherein the or each layer of cells comprises from 28 to 35 cells.
15. The assembly according to any preceding claim, wherein the or each layer of cells of the dynamic mattress has a thickness of less than 10.0 cm.
16. The assembly according to claim 15, wherein the thickness is from 1.5 to 5.5 cm.
17. The assembly according to any preceding claim, wherein the uppermost layer of cells of the dynamic mattress are arranged into a first group X and a second group Y, with the cells in group X alternating with the cells in group Y along the length of the mattress.
18. The assembly according to claim 17, wherein the alternating pattern is XYXY along the length of the mattress.
19. The assembly according to either of claims 17 or 18, wherein the groups X and Y have substantially the same number of cells therein.
20. The assembly according to any of claims 17 to 19, wherein the cells in groups X and Y are alternately inflated and deflated.
21. The assembly according to claim 20, wherein the cells in group X are deflated and inflated while the cells in group Y are held at a substantially constant pressure.
22. The assembly according to any preceding claim, wherein a layer of protective material is provided between the dynamic mattress and the sprung base.
23. The assembly according to any preceding claim, further comprising a layer of support material overlying the dynamic mattress.
24. The assembly according to claim 23, wherein the support material is a polyurethane foam.
25. The assembly according to claim 24, wherein the polyurethane foam is a memory foam.
26. The assembly according to any of claims 23 to 25, wherein the support material modulates the action of the dynamic mattress on the body of the user.
27. The assembly according to any of claims 23 to 26, wherein the support material has a thickness of from 0.5 to 10.0 cm.
28. The assembly according to claim 27, wherein the support material has a thickness of from 2.0 to 5.0 cm.
29. The assembly according to any of claims 23 to 28, wherein the support material is retained within a cover.
30. The assembly according to any preceding claim, wherein the dynamic mattress is retained within a cover.
31. The assembly according to any preceding claim, wherein the sprung base is provided with a cover.
32. The assembly according to any preceding claim, comprising a first dynamic mattress and a second dynamic mattress alongside the first.
33. The assembly according to claim 32, wherein each mattress is provided with a respective cover.
34. The assembly according to claim 33, wherein the covers are joined together by a releasable fastener.
35. A method of assembling a bed assembly for a user, the method comprising: providing a first set of components comprising a plurality of sprung bases, each sprung base comprising a resilient spring assembly, the sprung bases of the first set differing in the properties of the spring assembly; providing a second set of components comprising a plurality of dynamic mattresses, each dynamic mattress comprising a plurality of laterally extending, inflatable cells, the dynamic mattresses of the second set differing in the properties and/or form of the cells; selecting a sprung base from the first set according to the needs of the user; selecting a dynamic mattress from the second according to the needs of the user; and assembling the sprung base and the dynamic mattress into a bed assembly as claimed in any preceding claim.
36. The method according to claim 35, further comprising: providing a plurality of layers of support materials of differing properties; selecting a layer of support material according to the needs of the user; and incorporating the layer of support material into the bed assembly.
37. A bed assembly substantially as hereinbefore described having reference to either of Figures 1 or 2.
38. A method of assembling a bed assembly substantially as hereinbefore described having reference to either of Figures 1 or 2.