WO2013136067A1

WO2013136067A1 - A column for a body support unit and an associated method

Info

Publication number: WO2013136067A1
Application number: PCT/GB2013/050612
Authority: WO
Inventors: Joe KATAN
Original assignee: Balluga Limited
Priority date: 2012-03-13
Filing date: 2013-03-13
Publication date: 2013-09-19
Also published as: GB201218387D0; GB201218926D0

Abstract

A column (4) for a body support unit, comprising: a fluid-fillable component (2); and a restraining arrangement (50) substantially surrounding at least a part of the fluid-fillable component.

Description

A column for a body support unit and an associated method

The present invention relates to a column for a body support unit and a method of manufacturing a column for a body support unit.

This application claims priority to US provisional applications 61/610246, 61/618135 and 61/673518 and UK patent applications 1218387.7 and 1218926.2, the entire contents of which are herein incorporated in their entirety.

There is a requirement to provide a comfortable body support platform for human beings. The most common body support platforms are furniture including beds, couches, sofas, seats, benches, chairs, sofas etc. Other body support platforms can include operating tables, physiotherapist's tables, dentist's chairs, sun-beds etc. Thus the term body support platform encompasses any construction having a support surface on which a human being lies or sits for a period of time.

The support surface that is required to provide body support for the longest period of time in any person's life is a bed. A great deal of work has been carried out in the field of conventional beds and mattresses in order to provide a comfortable sleeping position for people overnight. One of the problems is that people vary greatly in height and weight as well as their physical condition. For example some people are prone to back conditions.

Conventional mattresses are formed from a number of springs linked to form the mattress. Such springs are not able to move independently. To provide for different weight people, mattresses can be provided with different spring tensions e.g. soft, medium and firm. However, the spring tension is applied across the whole of the mattress and hence cannot compensate for different user's body shapes. Also, if, after time, certain springs of the mattress become damaged or worn, or if the body shape or weight of the person changes, it is not possible to replace the springs. The mattress is a sealed unit. It can only be turned to offer a different spring region to the user's body regions.

Once a mattress is worn, the only option is for it to be disposed of. Recycling of conventional mattresses is difficult because of the unitary nature of the mattress and the mixture of types of material used. This presents a significant environmental issue. The unitary nature of conventional mattresses provides a barrier to providing bespoke mattresses for users.

Further, since conventional mattresses are formed of springs and fabric material they are difficult and expensive to clean when they become soiled or infested with bed lice or other human disease agents.

Recently, a body support platform comprising a plurality of columns, each column comprising a stack of fluid-fillable substantially spherical resilient balls, has been developed, as described in co-pending PCT application number PCT/GB201 1/051946 (WO2012/049481) to the inventor. Each ball of a respective column is physically and fluidly connected to the adjacent ball(s) within said column, such that a column may be compressed substantially independently of a neighbouring column. A base provides a primary fluid reservoir and the columns are arranged in an array across the base. The columns are connected to the base such that the lowermost ball of each respective column is directly fluidly connected to the primary fluid reservoir. The uppermost ball of respective columns collectively define a body support surface.

The body support platform has significant advantages over a conventional mattress. For example, since the body support platform is comprised of individual columns of balls, each column acts substantially independently of the other. Further, the columns or even the individual balls can be removed from the body support unit, either for cleaning, maintenance or replacement. Still further, the behaviour (e.g. firmness etc) may be altered by configuring individual balls or columns.

In a preferred arrangement, the resilient balls maintain a substantially spherical shape when inflated. However, if the balls are over inflated, they may tend to misshape, perhaps due to approaching the elastic limit of the resilient material. If the thickness of the wall of the ball is not uniform, it will be appreciated that high fluid pressure may cause relatively thinner portions of the wall to bulge or perish.

The present invention seeks to address at least some of these problems. In one embodiment, the present invention provides a column for a body support unit, comprising: a fluid-fillable component ; and a restraining arrangement substantially surrounding at least a part of the fluid-fillable component.

Preferably, the fluid-fillable component comprises a stack of fluid-fillable cells.

Advantageously, the restraining arrangement extends from the lowermost cell in the stack to the uppermost cell in the stack.

Conveniently, the restraining arrangement comprises a sleeve.

Preferably, the restraining arrangement is comprised of a mesh.

Advantageously, the restraining arrangement is resilient in at least one direction.

Conveniently, the restraining arrangement is substantially non-resilient in at least one direction.

Preferably, the restraining arrangement is secured to the fluid-fillable component.

Advantageously, the restraining arrangement is at least partially embedded in the fluid-fillable component.

Conveniently, the column further comprises a cover substantially surrounding the restraining arrangement.

Preferably, the restraining arrangement is secured to the fluid-fillable component by a coating.

Advantageously, the restraining arrangement has a first resiliency and the fluid- fillable component has a second resiliency, the first resiliency being lower than the second resiliency.

The present invention further provides a body support unit comprising: a base: and a plurality of columns according to the invention, each attached to the base.

Preferably, the restraining arrangement is secured to the base. The present invention further provides a body support platform comprising a plurality of body support units according to the invention.

The present invention further provides a method of manufacturing a column for a body support unit, the method comprising: providing a fluid-fillable component; providing a restraining arrangement; and arranging the fluid-fillable component within the restraining arrangement;

Preferably, the method further comprises: filling the fluid-fillable component with fluid such that the outer surface of the fluid-fillable component contacts the inner surface of the restraining arrangement; and securing the restraining arrangement to the fluid- fillable component.

Advantageously, the method further comprises pre-forming at least one of the fluid- fillable component and restraining arrangement.

Conveniently, the fluid-fillable component comprises a stack of fluid-fillable cells.

Preferably, the restraining arrangement is configured so as to constrain the or each cell to a substantially spherical shape in use.

Conveniently, the restraining arrangement is a sheath.

Advantageously, the restraining arrangement is a mesh.

Preferably, securing the restraining arrangement to the member comprises covering the assembly.

Conveniently, covering the assembly comprises covering the assembly in a cover.

Advantageously, the restraining arrangement is secured to the fluid-fillable component by coating the assembly.

Preferably, the method comprises coating the assembly with an adhesive. Conveniently, the restraining arrangement is embedded within the coating. Advantageously, the method further comprises: filling the fluid-fillable component with fluid such that the outer surface of the fluid-fillable component contacts the inner surface of the restraining arrangement; and coating the fluid-fillable component and restraining arrangement.

Preferably, at least part of the filling and coating steps overlap.

Conveniently, the coating and/or covering provides a substantially smooth outer surface.

Advantageously, the step of arranging the fluid-fillable component within the restraining arrangement comprises: embedding the restraining arrangement at least partially within the surface of the fluid-fillable component.

Preferably, the fluid-fillable component is provided in at least a partially molten state.

The present invention further provides a method of manufacturing a part of a column for a body support platform, the method comprising: providing a first layer comprised of restraining material; providing a second layer comprised of fluid-impermeable material in an at least partially molten state; embedding the first layer at least partially within the second layer to create a reinforced membrane; and shaping at least part of the membrane into a substantially hemi-spherical cup.

Preferably, the method further comprises: forming two of said shaped cups; and adhering the rim of the first cup to the rim of the second cup, to provide a substantially spherical cell.

Conveniently, the two shaped cups are formed at the same time, between the same mandrel and mould.

Advantageously, adhering the rims comprises bonding.

Preferably, the method further comprises trimming any excess material outside of the adhered rims. Conveniently, the method comprises shaping the membrane into a series of linearly arranged, substantially hemispherical, cups interconnected by channels.

Advantageously, the method comprises providing two shaped membranes, adhering the rim of the first shaped membrane to the rim of the second formed membrane to form a column of substantially spherical cells fluidly connected to one another.

Preferably, the method further comprises installing a valve at the interface of the two rims.

Conveniently, the step of embedding the first layer into the second layer comprises applying a pressure to the layers.

Advantageously, the step of providing the second layer includes feeding a stock of non-molten fluid-impermeable material and heating at least a part of the material.

Preferably, the first layer of restraining material is provided in a substantially hemispherical shape prior to embedding at least part of the first layer into the second layer and forming at least part of the member into a substantially hemispherical cup.

The present invention further provides a method of manufacturing a component for a body support platform, comprising: providing a first substantially hemispherical membrane comprised of restraining material; providing a second substantially hemispherical membrane comprised of fluid-impermeable material in an at least partially molten state; and embedding the first layer at least partially within the second layer to create a reinforced substantially hemi-spherical cup.

The present invention further provides a component for a body support platform, having a membrane comprised of a first layer of a restraining material embedded within a second layer of fluid-impermeable material, the membrane formed into a substantially hemi-spherical cup.

The present invention further provides a method of manufacturing a fluid-fillable component for a body support platform, the method comprising: forming a shaped restraining sheath; and coating the restraining sheath with a fluid-impermeable material. Preferably, the restraining sheath is formed by knitting.

The present invention further provides a method of manufacturing a column for a body support unit, the method comprising: providing a pre-formed restraining arrangement; and spraying or dipping the restraining arrangement with/into a molten fluid-impermeable material.

Preferably, the step of providing the restraining arrangement comprises applying at least one bead of restraining material onto the fluid-fillable component.

Conveniently, the method includes the step of filling the fluid-fillable component with fluid prior to the application of the bead of restraining material.

Advantageously, a plurality of beads of restraining material are applied, at least one of the beads being overlaid by at least one other bead.

Preferably, the plurality of beads of restraining material are applied to the member in a lattice.

Conveniently, the step of applying a lattice of beads comprises: applying a plurality of substantially parallel beads in a direction along the longitudinal axis of the member; and applying a plurality of substantially parallel beads around the member in a direction generally perpendicular to the longitudinal axis of the member.

Advantageously, the bead of restraining material is applied in an at least partially molten state.

Preferably, the method further comprises curing the bead of restraining material and subsequently deflating the column.

The present invention further provides a method of manufacturing a fluid-fillable component for a body support unit, the method comprising: providing a fluid-fillable elastic member; inflating the member; and applying at least one bead of restraining material onto the member to restrain subsequent inflation of the elastic member beyond a predetermined dimension. The contents of provisional applications US61/608931 , US61/608894 and U61/610246 are herein incorporated by reference in their entirety.

Embodiments in the present invention will now be described, by way of non-limiting example only, with reference to the figures, in which:

Figure 1 shows a bed (body support platform) embodying the present invention;

Figure 2 schematically illustrates a column of balls of the bed shown in figure 1 ;

Figures 3 and 4 show part of a cut-away column embodying the present invention;

Figures 5(a) and 5(b) schematically illustrate a method of manufacturing a column according to an embodiment of the present invention;

Figure 6 shows a cross-section of part of a column according to one embodiment of the present invention;

Figure 7 shows a cross-section of part of a column according to another embodiment of the present invention;

Figure 8 schematically illustrates another method of manufacturing a column according to an embodiment of the present invention;

Figure 9 shows a cross-section of the resultant membrane from the method illustrated in Figure 8;

Figures 10(a) and 10(b) schematically illustrate another method of manufacturing a column according to an embodiment of the present invention;

Figure 1 1 shows a fluid-fillable component prior to inflation;

Figure 12 shows the fluid-fillable component of Figure 1 1 inflated;

Figures 13a - 13c illustrate a method of manufacturing a column for a body support unit according to another method embodying the present invention; and Figure 14a-14c illustrate a method of manufacturing a column for a body support unit according to another method embodying the present invention.

Embodiments of the present invention will be described with reference to a bed. It should however be understood that the embodiments are equally applicable to any body support platform. Likewise, although the illustrated embodiments comprise a 'ball', the embodiments are equally applicable to any 'cell'.

Figure 1 illustrates a bed 1 formed from a plurality of balls 2. The balls 2 in Figure 1 are arranged generally in four layers 3a, 3b, 3c, 3d and in columns 4. An upper surface of the uppermost layer 3a of balls defines a body support surface. Although in this embodiment four layers of balls 2 are shown, any number of layers 3 can be used. For example, an embodiment comprising columns of three balls 2 is illustrated in figures 2 to 4.

As shown in Figure 1 , the bed 1 is formed of a bed frame 51. The columns 4 of balls 2 are arranged into a plurality of body support units 50. In Figure 1 , the units 50 are depicted with different shading.

Each unit 50 comprises a plurality of columns 4 of balls 2. As depicted in figure 2, each ball 2 of a respective column 4 is physically and fluidly connected only to the adjacent ball(s) 2 within said column 4, such that a column 4 may be compressed substantially independently of a neighbouring column 4. As shown in Figure 1 , the unit 50 comprises a base 52 which provides a primary fluid reservoir. The columns 4 are arranged in an array across said base 52; and each of said columns 4 is connected to said base 52, such that the lowermost ball 2 of each respective column 4 is directly fluidly connected to said primary fluid reservoir. Preferably, the balls 2 are arranged in a regular grid pattern across the base 52, in an N x M matrix.

When the uppermost ball in a respective column 4 is compressed, the pressure of the fluid inside the ball 2 increases and fluid is caused to flow freely into the primary fluid reservoir. When the uppermost ball 2 of column 4 is compressed, the pressurised fluid is transmitted to the second ball which, in turn, is transmitted to the third ball. Subsequently, the pressurised fluid passes into the reservoir until the pressure between the column and the reservoir is balanced. Fluid will not necessarily flow into other columns 4. One benefit of this arrangement is that it promotes a balancing of pressure in the balls 2 across the body support surface. Preferably, the volume of the reservoir is far higher than the volume of an individual ball 2. The use of a reservoir substantially removes any resistance to the compression of the ball 2 or column 4. By comparison, connecting a plurality of columns 4 with a network of connecting conduits increases resistance to fluid flowing therethrough and creates back pressure.

The lowermost ball 2 in each column 4 is preferably removably connected to the base 52. For example, the base 52 could be provided with a bayonet spigot to which a corresponding fitting on the lowermost ball 2 of the column 4 is releasably connectable. Alternatively, the column 2 could be releasably connected by means of a screw fitting, resilient fitting or other suitable means.

Figures 3 and 4 illustrate part of a column according to the invention. The column 20 comprises a plurality of balls 21 formed integrally with one another. A neck 22 is provided at the intersection of each ball 21 , to allow fluid to pass between the balls 21 in the column 20. A port 23 is provided at the bottom of the column 20, for connection to a fluid supply. The port 23 comprises a valve member 24, comprising a generally cylindrical threaded boss 25 and radially extending flange 26. The flange 26 is passed through an aperture 27 in the base of the column. The flange 26 may be provided within the mould of the column 20 during manufacture, or may be inserted after manufacture of the column 20. In one embodiment, the resiliency of the material of the column 20 is such that the aperture 27 of the column can be stretched over the flange 26.

As shown in Figure 1 , the columns are secured to a base 52, which preferably includes a reservoir or supply network of fluid (e.g. air). In use, the boss 25 protrudes through a hole provided in a depression of the base 52. Then, a nut 29 is screwed onto the threaded boss 25 and tightened. As it is tightened, the base of the column 20, adjacent the aperture 27, is effectively clamped between the flange 26 and the base 52, creating a hermetic seal. Accordingly, fluid can only enter and leave the column 20 through a bore 30 in the boss. Preferably, the underside of the flange includes ridges and/or depressions 28, which serve to promote the hermetic seal and/or effective grip of the column 20 with respect to the flange 26.

A method of manufacturing a column for a body support unit will now be described, with reference to figures 5(a) and 5(b). Figure 5(a) shows a shaped restraining sheath 50. In the embodiment shown, the sheath 50 is comprised of a mesh, (illustrated by use of the dotted line). The sheath 50 is preformed into the desired shape of the component for the body support platform. The restraining sheath is shaped generally into a linear array of connected spheres 51 representative of the shape of a column 4.

The restraining sheath 50 of the present invention is flexible and preferably comprised of polypropylene, polyester or any other substantially inextensible material. As described below, the material of the restraining sheath may alternatively be at least partially resilient. Whether the sheath is inextensible or resilient is not essential to the method of manufacture. Any of the methods described herein may use inextensible or resilient material for the sheath.

Figure 5(a) further shows a fluid-fillable component 52. In this embodiment, the component 52 is a column of fluid-impermeable material comprising a plurality of fluidly-connected, substantially spherical, cells 53. Each cell 53 has a wall defining a fluid-fillable chamber therein.

According to a method embodying the present invention, the fluid-fillable component 52 is arranged within the retraining sheath 50. In one embodiment, the component 52 is inserted into the sheath 50. In another embodiment, the sheath 50 may be assembled over the fluid-fillable component 52. The assembly of the sheath 50 and component 52 is performed when the component 52 is not filled with fluid under pressure. Accordingly, during the assembly, the component 52 may be laterally compressed so as to fit through the opening into the sheath 50.

As shown in figure 5(b), when the component 52 is arranged inside the sheath 50, the component 52 is then inflated with fluid (e.g. air), causing the individual cells 53 of the column to expand. The cells 53 expand until the outer surface of the component 52 contacts the inner surface of the sheath 50. When the sheath is comprised of inextensible material, the sheath 50 substantially prevents any further expansion of the component 52 beyond a predetermined dimension. When the sheath is alternatively comprised of resilient material, some further expansion of the component 52 is permitted. Conveniently, the sheath 50 is shaped such that, upon inflation of the component 52, the assembly 54 defines a column of substantially spherical cells representative of the column shown in figures 1 to 4. The reinforcing sheath 50 provides reinforcement to the fluid-fillable component 52, to prevent the component 52 over-inflating, bulging and/or perishing under pressure. The method embodying the present invention further comprises securing the sheath 50 to the component 52, as illustrated in figures 6 and 7.

Figure 6 is cross-section of a part of the assembly 54 of figure 5(b), with the addition of a cover 55. It will be noted from figure 6 that the outer surface of the component 52 contacts the inner surface of the sheath 50. Additionally, a cover 55 is provided around the outside of the assembly 54, sandwiching the sheath 50 between the cover 55 and the cell wall of the component 52. The mechanical properties of the cover 55 are not of particular importance, but the cover 55 is preferably flexible. The cover 55 is preferably preformed, having substantially the same shape as the sheath 50. The sheath 50 may be assembled inside the cover 55, before the component 52 is then inserted into the sheath 50/cover 55 assembly.

In one embodiment, the sheath 50 is adhered to the inside surface of the cover 55. The inner surface of the sheath 50 may be adhered to the outer surface of the wall of the component 52.

Conveniently, the cover 55 provides a substantially smooth outer surface, allows the component to be easily cleaned, and also presents fewer areas which may harbour bed lice or other human disease agents.

Figure 7 shows another embodiment of the present invention. Rather than use a discrete cover (as in figure 6), the arrangement in figure 7 comprises a coating 56 on the assembly 54, which provides both a smooth outer surface and also serves to secure the sheath 50 to the outer surface of the component 52. The coating 56 may be applied by dipping the assembly into the coating material, or the coating may be sprayed on to the outer surface of the assembly.

In the arrangement shown in figure 6, the sheath 50 is held in place against the component 52 by the substantially tight fitting cover 55. In the arrangement shown in figure 7, the sheath 50 is held against the component 52 by virtue of being held against the component 52 with the coating 56. Alternatively or additionally, the inside surface of the sheath 50 may be adhered to the outer surface of the component 52. In one embodiment, the steps of inflating the component 52 and coating the assembly may at least partially overlap. Consequently, some of the coating 56 may be deposited between the inner surface of the sheath 50 and the outer surface of the component 52, thereby promoting adhesion between the two. The coating 56 provides additional securement of the sheath 50 to the component 52 and provides a smooth outer surface. It is to be noted from figure 7 that the sheath is embedded within the coating.

Following the securement of the sheath 50 to the component 52 - by way of a cover 55 or a coating 56 - the fluid-fillable component may then be deflated for storage or transportation. Even when not inflated with fluid, the sheath 50 will remain secured to the outer surface of the component 52, preventing any misalignment.

The fluid-fillable component, preferably a column as shown in figure 3 or 4, can then be installed on a body support platform (figure 1). In use, regardless of the pressure of the fluid inside the column, the individual spherical cells of the column will maintain their spherical shape.

Figure 8 schematically illustrates part of another method of manufacturing a column for a body support platform.

The method comprises providing a first layer 58 comprised of restraining material. The method further comprises providing a second layer 57 of fluid-impermeable material in an at least partially molten state. In its molten state, the fluid- impermeable material is preferably not in a fluid state, but rather a discrete layer which is substantially pliable.

The first layer 58 is then at least partially embedded within the second layer 57 to create a reinforced membrane. The molten state of the second layer 57 of fluid- impermeable material is such that pressing the first layer 58 of restraining material into the surface of the second layer 57 causes at least some of the material to be displaced.

In the embodiment shown in figure 8, rollers 59 are provided, which apply pressure to the first 58 and second 57 layers and serve to promote the embedding process. However, in one embodiment, outside pressure is not required, and the weight of the first layer 58, in combination with the molten state of the second layer 57, is sufficient to promote embedding of the first layer 58 into the second layer 57.

The method schematically illustrated in figure 8 creates a reinforced membrane 60, as shown in cross-section in figure 9. The embedded first layer 58 (a mesh) is shown under the surface of the second layer 57. Both the upper and lower surfaces of the reinforced membrane 60 are substantially smooth.

The final step of the method embodying the present invention is to shape at least a part of the membrane into a substantially hemispherical cup, as schematically shown in figures 10(a) and 10(b).

The assembly comprises a mandrel 61 and mould 62. The surfaces of both the mandrel 61 and mould 62 present a substantially hemispherical surface. The reinforced membrane 57 is arranged between the mandrel 61 and mould 62, and then the mandrel 61 and mould 62 are moved towards one another, and a pressure applied. This causes the reinforced membrane 60 to form a shaped membrane, at least part of which defines a substantially hemispherical cup.

In a preferred embodiment, the method comprises shaping the membrane 60 into a series of linearly arranged, substantially hemispherical, cups interconnected by channels, to form the "half-column" component shown in figures 3 and 4.

Two shaped membranes are subsequently then adhered to one another, to create a column for a body support platform. The hemispherical cups of two respective shaped membranes are adhered to one another about their rims, to provide a substantially spherical cell.

With reference to figures 3 and 4, the shaped "half-column" membranes are adhered to one another along their respective rims to form a column of substantially spherical cells fluidly connected to one another.

Preferably, before or during the adhering of two shaped membranes to one another, a valve is arranged at the interface of the two rims, to provide a port into the cell/column. When two shaped membranes are adhered to one another, they are substantially hermetically sealed, apart from a port provided at the base.

The first layer 58 of restraining material is preferably a mesh.

In the embodiments shown in figures 8 to 10(b), a substantially planar reinforced membrane is first manufactured, before then being formed into a shaped membrane, at least part of which is a substantially hemispherical cup. In another arrangement, both the first layer 58 of restraining material and the second layer 57 of fluid impermeable material may both be preformed into a hemispherical membrane. The first and second hemispherical membranes are then brought together to form a reinforced substantially hemispherical cup.

In another method, the two shaped cups are formed at the same time, between the same mould and mandrel, by inserting a sandwich of two layers of membrane between the mould and mandrel. After the two cups are shaped, the rims of the two cups are bonded together by appropriate means. In one embodiment, the rims of the cups are bonded at the same time as being formed.

Preferably, any excess material (flashing) outside of the bond is trimmed. In one embodiment, the trimming occurs at the same time as the bonding and forming of the cups. Conveniently, a complete cell can thus be created from two membranes in a single step.

After removing the cell from the mould, it is turned inside out - through an opening in one of the cups or at the interface of the cups - so that the bond (and any remaining flashing) is on the inside of the cell, to give a substantially smooth finish to the exterior of the cell in use.

In one embodiment, the restraining sheath is resilient, rather than being substantially inextensible. Preferably, the resiliency of the sheath is less than the resiliency of the fluid-impermeable material of the fluid fillable component. The sheath has a first resiliency and the fluid-impermeable material has a second resiliency.

In use, as a fluid fillable cell manufactured from the membrane is inflated, the resiliency of the fluid-impermeable material allows for the cell to stretch, offering relatively little resistance. As the cell inflates further, it will reach a point where it reaches a substantially spherical shape. Beyond this point, the resiliency of the restraining sheath imparts a restrictive force on the cell, such that a higher pressure of gas is needed to inflate the cell further. This serves to restrict over- inflation of the cell (e.g. column) beyond a predetermined size. If the sheath was inflexible, not allowing the cell to expand beyond a predetermined size, the behaviour of the cell might be adversely affected. Further inflation would cause the pressure of the cell to increase, until the cell is relatively hard. By providing a resilient restraining sheath, the effects of over-inflation are mitigated, by affectively serving to constrain - but not entirely restrict - the further inflation.

The stress-strain gradient is preferably greater for the sheath than the fluid- impermeable material of the fluid-fillable component.

In embodiments of the invention, the restraining sheath may be fabricated by knitting the sheath as an integral item. Preferably, the sheath is knitted so as to substantially take the form of the sheath as shown in Figure 5(a), wherein the diameter of the sheath varies over the axial length of the sheath. By knitting the sheath as an integral item, there are no seams along the length of the sheath. Both ends of the knitted sheath may be open, with one end being subsequently sewn to close the end. Alternatively, a closed end may be formed during the knitting process.

In one embodiment, the sheath can then be dipped into, or sprayed with, fluid- impermeable material to create the column. An advantage of dipping or spraying the sheath is that the fluid-impermeable material will be physically keyed to the sheath. When the sheath has been knitted and removed from the knitting apparatus, it will likely not hold its shape unaided. Accordingly, when the sheath is being coated (dipped or sprayed etc) with fluid-impermeable material, the sheath may be placed over a form or partially inflated so as to substantially define the intended shape. This may assist in the coating or dipping process and ensure more even coating.

In another embodiment, the shaping of the sheath (by a form or inflation) during the coating process may not be so important. If the sheath is oriented vertically, and lowered into a bath of molten fluid-impermeable material, although it may not exactly hold its intended shape, the fluid-impermeable material will nevertheless contact all the surfaces of the sheath. Alternatively, the sheath may be placed on a horizontal surface for the coating process, wherein the sheath will almost certainly collapse such that the wall on one side contacts the wall of the other side of the sheath. Nevertheless, dipping or spraying the sheath will still allow the fluid-impermeable material to contact the surfaces of the sheath.

After dipping or coating the sheath, the fluid-impermeable material may then be cured.

With reference to figs 1 1 to 14, another method of manufacturing a column comprises applying at least one bead of restraining material onto the fluid fillable component to restrain subsequent inflation of the column beyond a predetermined dimension.

Figure 1 1 illustrates a fluid-fillable component 150 prior to inflation. The component 150 is preferably pre-formed as a single item in a mould and manufactured from a synthetic rubber.

Figure 12 schematically illustrates the fluid-fillable component 150 when inflated by a fluid supply 151 , in which it comprises a linear series of substantially spherical cells 2 connected to one another.

With reference to figure 13a, the inflated fluid-fillable component 150 is passed through a restraining material application unit 152, which applies a plurality of beads 153 along the length of the inflated component 150, parallel to the longitudinal axis of the component 150. Subsequently, preferably after the restraining material is cured, the inflated component 150 is rotated by 90° about its longitudinal axis, and passed through the restraining material application unit 152 once more. The beads of material 153 are preferably at least partially molten when applied.

The resultant column is schematically shown in figure 13c, wherein a lattice 154 of restraining material is provided over the outer surface of the component 150. When the restraining material is cured, subsequent inflation of the component 150 is restrained beyond a predetermined dimension. Accordingly, any over-inflation of the component 150 is reduced or prevented, to prevent the component 150 becoming misshapen in use.

An alternative method of applying the restraining material is shown in figures 14a to 14c. The first step, shown in figure 14a, applies a plurality of beads of restraining material on the outer surface of the component, in a direction parallel to the longitudinal axis. Subsequently, with reference to figure 14b, circumferential beads 153 of restraining material are provided around the component 150, to provide a component 150 having a lattice work 155 of restraining material, as shown in figure 12c, to create a column.

Other configurations and/or application methods of the restraining material on the member are possible. Preferably, the beads of restraining material intersect one another.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A column for a body support unit, comprising:

a fluid-fillable component ; and

a restraining arrangement substantially surrounding at least a part of the fluid- fillable component.

2. A column according to claim 1 , wherein the fluid-fillable component comprises a stack of fluid-fillable cells.

3. A column according to claim 2, wherein the restraining arrangement extends from the lowermost cell in the stack to the uppermost cell in the stack.

4. A column according to any preceding, wherein the restraining arrangement comprises a sleeve.

5. A column according to any preceding claim, wherein the restraining arrangement is comprised of a mesh.

6. A column according to any preceding claim, wherein the restraining arrangement is resilient in at least one direction.

7. A column according to any preceding claim, wherein the restraining arrangement is substantially non-resilient in at least one direction.

8. A column according to any preceding claim, wherein the restraining arrangement is secured to the fluid-fillable component.

9. A column according to any preceding claim, wherein the restraining arrangement is at least partially embedded in the fluid-fillable component.

10. A column according to any preceding claim, further comprising a cover substantially surrounding the restraining arrangement.

1 1. A column according to any preceding claim, wherein the restraining arrangement is secured to the fluid-fillable component by a coating.

12. A column according to any preceding claim, wherein the restraining arrangement has a first resiliency and the fluid-fillable component has a second resiliency, the first resiliency being lower than the second resiliency.

13. A body support unit comprising:

a base:

a plurality of columns according to any preceding claim, each attached to the base.

14. A body support unit according to claim 13, wherein the restraining arrangement is secured to the base.

15. A body support platform comprising a plurality of body support units according to either of claims 13 or 14.

16. A method of manufacturing a column for a body support unit, the method comprising:

providing a fluid-fillable component;

providing a restraining arrangement; and

arranging the fluid-fillable component within the retaining arrangement;

17. A method according to claim 16, further comprising:

filling the fluid-fillable component with fluid such that the outer surface of the fluid-fillable component contacts the inner surface of the restraining arrangement; and

securing the restraining arrangement to the fluid-fillable component

18. A method according to claim 16, further comprising pre-forming at least one of the fluid-fillable component and restraining arrangement.

19. A method according to any of claims 16 to 18, wherein the fluid-fillable component comprises a stack of fluid-fillable cells.

20. A method according to claim 16, wherein the restraining arrangement is configured so as to constrain the or each cell of the component to a substantially spherical shape.

21. A method according to any of claims 16 to 20, wherein the restraining arrangement is a sheath.

22. A method according to any of claims 16 to 21 , wherein the restraining arrangement is a mesh.

23. A method according to claim 17, wherein securing the sheath to the member comprises covering the assembly.

24. A method of claim 23, wherein covering the assembly comprises covering the assembly in a cover.

25. A method according to claim 16, wherein the restraining arrangement is secured to the fluid-fillable component by coating the assembly.

26. A method according to claim 25, comprising coating the assembly with an adhesive.

27. The method according to claim 26, wherein the restraining arrangement is embedded within the coating.

28. A method according to claim 25, comprising :

coating the fluid-fillable component and restraining arrangement.

29. A method according to claim 28, wherein at least part of the filling and coating steps overlap.

30. A method of any of claims 28 or 29, wherein the coating and/or covering provides a substantially smooth outer surface.

31. A method according to any of claims 16 to 30, wherein the step of arranging the fluid-fillable component within the restraining arrangement comprising:

embedding the restraining arrangement at least partially within the surface of the fluid-fillable component.

32. A method according to claim 31 , wherein the fluid-fillable component is provided in at least a partially molten state.

33. A method of manufacturing a fluid-fillable component for a body support platform, the method comprising:

providing a first layer comprised of restraining material;

providing a second layer comprised of fluid-impermeable material in an at least partially molten state;

embedding the first layer at least partially within the second layer to create a reinforced membrane;

shaping at least part of the membrane into a substantially hemi-spherical cup.

34. A method according to claim 33, comprising:

forming two of said shaped cups; and

adhering the rim of the first cup to the rim of the second cup, to provide a substantially spherical cell.

35. A method according to claim 34, wherein the two shaped cups are formed at the same time, between the same mandrel and mould.

36. A method according to claim 34, wherein adhering the rims comprises bonding.

37. A method according to any of claims 34 to 36, further comprising trimming any excess material outside of the adhered rims.

38 A method of claim 36, comprising shaping the membrane into a series of linearly arranged, substantially hemispherical, cups interconnected by channels.

39. A method of claim 38, comprising providing two shaped membranes, adhering the rim of the first shaped membrane to the rim of the second formed membrane to form a column of substantially spherical cells fluidly connected to one another.

40. A method of claims 34 to 39, further comprising installing a valve at the interface of the two rims.

41. A method according to claim 33, wherein embedding the first layer into second layer comprises applying a pressure to the layers.

42. A method according to claim 33, wherein the step of providing the second layer includes feeding a stock of non-molten fluid-impermeable material and heating at least a part of the material.

43. A method according to claim 33, wherein the first layer of restraining material is provided in a substantially hemi-spherical shape prior to embedding at least part of the first layer into the second layer and forming at least part of the member into a substantially hemispherical cup.

44. A method of manufacturing a component for a body support platform, comprising:

providing a first substantially hemispherical membrane comprised of restraining material;

providing a second substantially hemispherical membrane comprised of fluid- impermeable material in an at least partially molten state;

embedding the first layer at least partially within the second layer to create a reinforced substantially hemi-spherical cup.

45. A component for a body support platform, having a membrane comprised of a first layer of a restraining material embedded within a second layer of fluid- impermeable material, the membrane formed into a substantially hemi-spherical cup.

46. A method of manufacturing a fluid-fillable component for a body support platform, the method comprising:

forming a shaped restraining sheath;

coating the restraining sheath with a fluid-impermeable material.

47. A method according to any of claims 16 to 46, wherein the restraining sheath is formed by knitting.

48. A method of manufacturing a column for a body support unit, the method comprising:

providing a pre-formed restraining arrangement; and spraying or dipping the restraining arrangement with/into a molten fluid- impermeable material.

49. A method according to claim 16, wherein the step of providing the restraining arrangement comprises applying at least one bead of restraining material onto the fluid-fillable component.

50. A method according to claim 49, including the step of filling the fluid-fillable component with fluid prior to the application of the bead of restraining material.

51. A method according to any of claims 49 and 50, wherein a plurality of beads of restraining material are applied, at least one of the beads being overlaid by at least one other bead.

51. A method according to claim 51 , wherein the plurality of beads of restraining material are applied to the component in a lattice.

52. A method according to claim 51 , wherein the step of applying a lattice of beads comprises:

applying a plurality of substantially parallel beads in a direction along the longitudinal axis of the component,

applying a plurality of substantially parallel beads around the component in a direction generally perpendicular to the longitudinal axis of the component.

53. A method according to any of claims 49 to 52, wherein the bead of restraining material is applied in an at least partially molten state.

54. A method according to any of claims 49 to 53, further comprising curing the bead of restraining material and subsequently deflating the column.

55. A method of manufacturing a fluid-fillable component for a body support unit, the method comprising:

providing a fluid-fillable elastic member;

inflating the member; and

applying at least one bead of restraining material onto the member to restrain subsequent inflation of the elastic member beyond a predetermined dimension.