GB2519528A

GB2519528A - Beds

Info

Publication number: GB2519528A
Application number: GB1318682.0A
Authority: GB
Inventors: Stewart Gregory; Mark Shipley
Original assignee: MAD WOLF INNOVATIONS Ltd
Current assignee: MAD WOLF INNOVATIONS Ltd
Priority date: 2013-10-22
Filing date: 2013-10-22
Publication date: 2015-04-29
Anticipated expiration: 2033-10-22
Also published as: GB2519528B; GB201318682D0

Abstract

An inflatable bed (10) comprising a pneumatic base (12) and a pneumatic mattress (14), wherein the base (12) comprises a drop-stitch core (50). The mattress (14) may additionally comprise a drop-stitch core (50). The drop-stitch core (50) suitably comprises an upper sheet of flexible material (52), a lower sheet of flexible material (54) and space yarns (56) interconnecting the upper (52) and lower (54) flexible sheets. The use of a drop-stitch core suitably renders base relatively rigid, such that it may be able to act as a structural component of the bed. By comprising a drop-stitch core, the base can be made relatively high, to elevate the mattress (and the user) much higher above floor level than can be achieved using a conventional pneumatic mattress alone, whilst retaining structural stiffness that reduces the likelihood of the base tipping or collapsing under the weight to a user.

Description

Title: Beds

Description:

This invention relates to beds, and in particular, to pneumatic beds.

Beds can be used for a number of purposes besides sleeping, such as, transporting people and animals, elevating objects off a floor surface, medical uses and so on. Most beds comprise a base, which can be a bed frame (cf. a bedstead) or a box-like structure (cf. a divan), which is used to support a mattress above a floor surface. Most beds are installed and remain in-situ for extended periods of time, and so a frame-or box-type base is generally acceptable.

However, in emergency situations, for example, in the event of an earthquake or other natural disaster, war or civil unrest, it is often necessary to set-up ad-hoc accommodation units, hospital wards and the like at short notice. In most cases, camp beds can provide an adequate short-term sleeping solution, but camp beds are unsuitable for use over extended periods of time: they are not very comfortable and are damage prone. Pneumatic mattresses, or "air beds" are also used to provide temporary sleeping solutions, but airbeds are susceptible to punctures, and due to their air cell construction, are not very comfortable to sleep upon. Moreover, airbeds are often unsuitable for overweight users, who risk bursting the airbed or lying on the floor if the airbed is unevenly, or point-loaded. Moreover, airbeds and camp beds do not elevate the user above floor level very much, which can be dangerous and unhygienic is certain situations.

A need therefore exists for a new, improved and/or alternative type of bed that offers one or more of the following advantages: small size for storage andJor transportation, ease and/or speed of deployment, durability, comfort; and which addresses some of the shortcomings of conventional camp beds and pneumatic mattresses.

According to an aspect of the invention, there is provided a bed comprising a pneumatic base and a pneumatic mattress, wherein the base comprises a drop-stitch core.

The use of a drop-stitch core suitably renders base relatively rigid, such that it may be able to act as a structural component of the bed. By comprising a drop-stitch core, the base can be made relatively high, to elevate the mattress (and the user) much higher above floor level than can be achieved using a conventional pneumatic mattress alone, whilst retaining structural stiffness that reduces the likelihood of the base tipping or collapsing under the weight to a user. In one embodiment, the base is equivalent to a box-base (or divan bed base), i.e. a relatively hard and rigid box structure for supporting the mattress above it.

In certain embodiments of the invention, the mattress additionally comprises a drop stitch core.

The bed suitably comprises means for affixing the mattress to the base. The means for affixing may comprise a strap overlying the mattress, which strap is connectable, in use, to the base.

The strap may be length-adjustable, and may additionally be provided with a quick-release buckle, clip or clasp arrangement. Additionally or alternatively, the means for affixing may comprise a hook and loop type fastener interposed between the mattress and the base.

Means is suitably provided for separating a portion of the mattress from the base. Such means may comprise an inflatable insert which can be inserted, in use, between the mattress and the base.

The base and/or the mattress may comprise a plurality of chambers, at least one of which chambers comprises the drop-stitch core. In one embodiment, the base or mattress comprises a central portion surrounded by a peripheral portion, the central and peripheral portions comprising separate pneumatic chambers. The separate pneumatic chambers can be inflatable independently or in unison. The central and/or peripheral portion may each comprise a plurality of chambers, which chambers may be stacked on top of each other.

Where the base or mattress comprises more than one chamber, valve means is suitably interposed between the chambers to facilitate sequential inflation and/or deflation of the chambers.

The valve suitably comprises a diverter valve for selectively diverting the flow of inflation air (or the scape of deflation air) to a selected one of the chambers, or to atmosphere.

In certain embodiments of the invention, the separate pneumatic chambers are in fluid communication with one another and are inflatable as one.

Embodiments of the invention shall now be described, by way of example only, with reference to the accompany drawings, in which: Figure 1 is a perspective view of an embodiment of a bed in accordance with the invention; Figure 2 is a perspective view of the bed of Figure 1 in a first alternative configuration; Figure 3 is a perspective view of the bed of Figure 1 in a second alternative configuration; Figure 4 is a partially cut-away, schematic view of the base of the bed of Figure 1; Figure 6 is a perspective view of a first alternative base configuration for a bed according to the invention; Figure 6 is a perspective view of a second alternative base configuration for a bed according to the invention; Figures 7 to 10 are a series of pneumatic circuit diagrams illustrating an inflation sequence for the base of Figure 6; Figure 11 is a perspective view of a transfer unit for the beds of Figures 1 to 10; Figure 12 is a perspective view of the transfer unit of Figure 11 folded; and Figure 13 is a perspective view of a bed in accordance with the invention on the transfer unit of Figure 11 and fitted with various accessories.

A bed 10 in accordance with the invention is shown in Figure 1 of the drawings, which comprises a pneumatically-inflatable base 12 and a pneumatic mattress 14. The base 12 rests on the floor 16 and supports the mattress 14 at an elevated position above floor level, in this case, approximately 400mm off the floor 16.

The mattress 14, which is approximately lOOm thick, sits on top of the base 12 and is held in place by strips of hook-and-loop fasteners 18 located on the top surface 20 of the base, and on the underside 22 of the mattress 12. The mattress 12 is also held in place by a strap 30 that wraps around the base 12 and mattress 14. The strap 30 comprises a quick-release buckle 32, which enables it to be detached easily, and which permits length adjustment so that the strap 30 can be located at different positions and orientations relative to the bed, as shown, for example, in Figure 2.

A further function of the strap 30 is to retain the mattress 14 to the base 12 along a "line of action". By tightening the strap 30, the mattress 14 can be compressed or wrinkled along the line of the strap to enable the mattress to be bent, as shown in Figures 1 and 2. In Figure 1, for example, the strap 30 extends laterally across the bed 10 and the mattress 14 is lifted up at one end to provide an inclined back support 34 for a user of the bed. The inclined portion 34 of the mattress 14 is supported from underneath by a wedge-shaped, inflatable insert 36. By changing the inflation pressure of the insert 36, the angle of inclination of the inclined portion 34 of the mattress 14 can be adjusted. Moreover, by changing the location and orientation of the strap 30, as shown for example in Figures 2 and 3, the mattress 12 can be used to elevate different parts of the body. Usefully, the configuration shown in Figure 4 can be used to support a user in a semi-supine, or "recovery" position. It will be noted in Figure 4 that several straps 30 have been connected end-to-end by their respective buckles 32 to extend the strap 3Oso that it can fit length-wise over the bed. Further, two inflatable inserts 36 are shown in Figure 4, although this is not necessarily always the case, as can be seen from Figure 2, for example.

The straps 30, or multiple straps 30, can, should the need arise, be used to connect two or more beds 10 together, side-by-side, end-to-end or in any desired configuration. It will also be appreciated that a plurality of bases 12 and mattresses 14 can be stacked on top of each other in any desired combination to achieve a desired elevation for a user.

The insert 36 additionally comprises strips of hook-and-loop fastener 40 that engage with complementary strips 28 of the base 12 and mattress 14, which together inhibit the insert 36 from being squeezed out of position as weight is applied to the mattress 14.

The base 12, as shown in greater detail in Figure 4, is a pneumatically-inflatable base for the bed 10. The base 12 comprises a drop-stitch core 50, which core 50 comprises an upper sheet of flexible material 52 and a lower sheet of flexible material 54. The two sheets 52, 54 are stitched together by space yarns 56, which are of substantially equal lengths and which are substantially evenly distributed across the surfaces of the upper 52 and lower 54 sheets. The space yarns 56 maintain the surfaces of the upper 52 and lower 54 sheets in a substantially flat and parallel configuration, and in so doing, the drop-stitch core 50 forms a flat, rigid beam-like structure within the base 12 when it is inflated.

Surrounding the core 50 is a thin, resiliently deformable foam layer 58, which provides protection for the drop-stitch core 50, and which conceals any lumps and bumps in the underlying structure when the base 12 is inflated.

Surrounding that, there is provided an airtight wrapper 60 for the base 12, which stops the inflation air from escaping. The wrapper 60 comprises planar upper and lower sheets 62, which overlie and underlie the drop-stitch core 50, respectively, and a sidewall 64 that extends round the sides of the base 12. The upper and lower sheets 62 and the sidewall 64 are sealingly glued and stitched 66 to one another to form an airtight seal.

Finally, a removable protective cover 70 is provided, which is manufactured, for example, from rip-stop fabric for durability, and which comprises a zip fastener 72 that enables the cover 70 to be removed for cleaning, maintenance and replacement.

The base is inflated via an air inflation valve 74, to which an air compressor (not shown) can be fitted to inflate the base 12. A small pilot line 76 communicates with the interior of the base 12, to which pilot line, an air pressure gauge (not shown) can be fitted, if required. A further use of the pilot line 76 is described below.

The base 12 of Figure 4 comprises a single drop-stitch core 50 and a single airtight surround 60 therefor. However, the base could be manufactured to comprise a plurality of discrete or interconnected chambers, such as illustrated in Figures 5 and 6.

In Figure 5, the base 12 comprises two chambers: an inner chamber 80 which is surrounded by a peripheral chamber 82. Either or both of the chambers 80, 82 may comprise a drop-stitch core such as that previously described. however, in one embodiment, only the peripheral chamber 82 comprises a drop-stitch core 50, whereas the inner chamber 80 is of a simple air-cell construction.

Such a configuration provides the structural rigidity benefits of having a drop-stitch core 50 to stabilise the base 12 and render it rigid, whereas the provision of an air-cell type central chamber 80 reduces the cost of manufacture (the size of the relatively expensive drop-stitch core 50 is reduced).

The inner 80 and peripheral 82 chambers can be inflated separately (e.g. to different pressures) or together, depending on user preferences.

The construction of the base 12 shown in Figure 6 comprises a layered structure of independently inflatable portions 84, 86, 88 each comprising a drop stitch core 50. The layers 84, 86, 88 are layered horizontally in use, so that the height if the base 12, and hence the elevation of the mattress (not shown) above the floor 16 can be adjusted by inflating one, two or all three of the layers 84, 86, 88. Inflation of the layers can be done independently, for example, having a separate inflation valve for each of the layers, or automatically, as shown in Figures 7 to 10 of the drawings.

In Figures 7 to 10, the layered structure of Figure 6 is shown, whereby there are three layers 84, 86, 88 of a base structure for a bed 10 described herein. An inlet valve 74 is provided in the upper layer 84 to which an air pump 90 is connected. The inlet valve 74 comprises a pressure-actuated diverter valve, which changes depending on the internal air pressure of the first chamber 84. when the internal air pressure within the first chamber 84 is below a threshold value, the air from the pump 90 is used to inflate the first chamber 84, as shown in Figure 7.

As more air is pumped into the first camber 84, the internal air pressure 92 increases, which acts upon a diaphragm of the diverter valve 74 to switch it to a second position, in which air from the pump 90 is now directed to an inlet 94 of the second chamber 86, and the outlet 99 to the first chamber 84 is sealed off. The second chamber 86 is thus inflated.

Inflation continues, as shown in Figure 9 in the same way, until the internal air pressure 92 in the second chamber 86 exceeds a threshold value, thereby moving a second diverter valve 74 to begin inflating the third chamber 86, and so forth. The procedure above can be repeated for any number of chambers, and it will be appreciated that such a configuration usefully allows the chambers to be inflated in a desired order (in this case, from top to bottom), depending on the configurations of the valves.

Finally, as shown in Figure 10, when all three chambers 84, 86, 88 are fully inflated, the third diverter valve 96 moves to a position whereby the air being pumped in by the pump 90 is diverted to the pilot line, where it acts upon a pressure switch to switch off the power supply 100 to the pump 90, thereby automatically halting the inflation procedure.

The diverter valve configuration illustrated above usefully ensures that the base 12 can be deflated in a reverse order since the diverter valves only revert to their initial positions when the respective chamber air pressures drop below their threshold values. Thus, depending on whether the first or last chamber in the sequence is vented to atmosphere, the base 12 will deflate in a corresponding order starting with the chamber which is first vented to atmosphere.

The construction and operation of the base 12 has been described in detail above, but it will be appreciated that all of the foregoing discussion applies equally to the mattress 14, which can be similarly constructed, i.e. having a drop-stitch core 50. Alternatively, the mattress 14 can be of a conventional "air cell" mattress design, depending on user requirements.

By providing a mattress 14 with a drop-stitch core 50, the amount of support can be adjusted by a user. When the mattress 14 (or base 12) is fully-inflated, the space yarns 56 become taut rendering the mattress 14 (or base 12) rigid, with a substantially hard, flat surface. However, if the internal pressure of the mattress 14 (or base 12) is reduced, the space yarns 56 become slack enabling the mattress 14 (or base 12) to behave and "feel" like a conventional air-cell mattress.

Thus, the mattress 12 hardness can be adjusted for comfort (by deflating it slightly) or for hardness (by fully inflating it) as desired.

S

Turning now to Figures 11 and 12, a transfer structure 120 for the bed (not shown) comprises a planar support platform manufactured from a box-section metal frame 122 for rigidity, with a planar board support surface 124 affixed thereto. The box-section metal frame 122 is made up of three parts: a pair of outer sections 126 and a central section 128 that are hingedly connected 129 to one another to allow the transfer structure 120 to be folded, as shown in Figure 12.

The metal frame 122 comprises four (or more) feet 130 that are located outwardly of the frame 122 for stability, thus ensuring that any load placed on the structure 120 is located inboard of the feet 130. The feet 130 are each manufactured from hollow metal tubes, and have axial through holes (not visible) therein for receiving the mounting pins (not visible) of lockable castors 132. The castors 132 can thus be connected to the feet 130 to support the frame 120 above floor level 16 thus allowing the structure 12 to be wheeled into position.

The support frame 120 additionally comprises a set of cranked braces 134 that carry the force of a load applied to the structure 120 when it is in its deployed configuration as shown in Figure 11, rather than the force being borne entirely by the hinges 129.

is when the structure 120 is folded away, for example, for storage and transportation, the mounting pins of the castors 132 can be inserted through transverse through holes 136 located in the sides of the feet 130 this enabling the structure 120 to be wheeled into position even when in the folded configuration.

The planar board support surfaces 124 additionally comprise ball transfer units (captive ball bearings) 125 that facilitate sliding a bed 10 onto and off the structure 120 when inflated. Thus, a bed 10 can be laid out on the structure 120, inflated and wheeled into position, and then slid off the structure 120 onto the floor. Alternatively, the bed 10 can remain on-board the support structure 120, as shown in Figure 13.

In Figure 13, the bed lOis strapped to the support structure 120 using the same straps 30 as are used for holding the base 12 and mattress 14 together, although separate straps 30 may be used for this purpose. As can be seen, the bed comprises two inflatable inserts 36 such that the foot area and the back area 34 can be elevated, as required.

A mains-powered air pump (not visible) is stored in pocket 140 located on a side of the base 12, and is powered by a mains power lead 142, although it could equally be connected to a battery power source (not shown). The air pump (not visible) is connected via tubes 144 to the base 12, mattress 14 and each of the inserts 36, and is controllable using a remote control unit 148. Thus, a user of the bed 10 is able to raise or lower the base 12, inflate or deflate the mattress 14 for comfort, and incline the foot 35 and back 34 portions, as required.

In addition, the feet 130 are also used to connect support poles 150 to the support structure 120, which poles 150 simply locate in the axial through holes of the feet 130. The support poles 150 can be used for a variety of purposes, such as, in the illustrated example, supporting an IV bag 152, patient records 154 or a computer 156. Thus, the bed 10 and support structure 120, along with its various accessories, can be used as a rapidly-deployable hospital bed suitable for use, for example, in

a field hospital or an evacuation centre.

Applications for the invention include, but are not limited to the following: Bariatric beds for obese or overweight persons: the drop-stitch core of the base providing stability where a conventional pneumatic mattress could allow the user to roll off the bed.

Emergency beds, for example, for use in emergency situations such as evacuation centres and field hospitals: the beds, being inflatable, could be collapsed to a small size for storage and/or transportation, but rapidly installed and inflated on-site to provide short-, medium-, or even long-term sleeping/rest/medical bed facilities.

Veterinary surgery: a bed according to the invention could be laid out on a floor surface in a deflated state. An animal, in particular, a large animal, such as a horse or elephant, could be anaesthetised whilst standing on the deflated bed. Once anaesthetised, and lying on the floor (atop the deflated bed), the bed could be inflated to safely elevate the animal to a height that is more convenient for the veterinary surgeon or staff. Suitably, a layered base structure, such as that described in figures 6 to 10 could be used in this instance to allow the operator to select an appropriate height.

Human surgery, first aid and recovery: the mattress of the bed can be adjusted in pressure (hardness), orientation and elevation (as shown in Figures 1 to 3) to support patients in a variety fo positions, depending on user preferences and medical necessity.

The invention is not restricted to the details of the foregoing embodiments, which are merely exemplary of the invention. The dimensions, ratios, materials and sizes, wherever provided, are illustrative rather than limiting and it will be understood that different materials, dimensions and constructions methods may be called for in different applications.

Claims

Claims: 1. A bed (10) comprising a pneumatic base (12) and a pneumatic mattress (14), wherein the base (12) comprises a drop-stitch core (50).
2. A bed (10) as claimed in claim 1, wherein the mattress (14) comprises a drop-stitch core (50).
3. A bed (10) as claimed in claim 1 or claim 2, wherein the drop-stitch core (50) comprises an upper sheet of flexible material (52), a lower sheet of flexible material (54) and space yarns (56) interconnecting the upper (52) and lower (54) flexible sheets.
4. A bed (10) as claimed in claim 3, wherein the space yarns (56) are of substantially equal lengths and which are substantially evenly distributed across the surfaces of the upper (52) and lower (54) sheets.
5. A bed (10) as claimed in any preceding claim, wherein the drop-stitch core (50) is surrounded by a resiliently deformable foam layer (58).
6. A bed (10) as claimed in any preceding claim, wherein the drop-stitch core (50) is surrounded by an airtight wrapper (60).
7. A bed (10) as claimed in claim 6, wherein the wrapper (60) comprises planar upper and lower sheets (62), which overlie and underlie the drop-stitch core (50), respectively, and a sidewall (64) that extends round the sides of the core (50), and wherein the upper and lower sheets (62) and the sidewall (64) are sealingly affixed to one another to form an airtight seal.
8. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a removable protective cover (70).
9. A bed (10) as claimed in claim 8, wherein the cover (70) is manufactured from rip-stop fabric and comprises a zip fastener (72) to permit the cover (70) to be removed.
10. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises an air inflation valve (74).
11. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a pilot line (76) communicating with the interior of the core (50).
12. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a plurality of chambers.
13. A bed (10) as claimed in claim 12, comprising an inner chamber (80) surrounded by a peripheral chamber (82).
14. A bed (10) as claimed in claim 13, wherein the peripheral chamber (82) comprises a drop-stitch core (50) and wherein the inner chamber (80) comprises an air-cell.
15. A bed (10) as claimed in claim 12, wherein the base (12) or mattress (14) comprises a layered structure of independently inflatable portions (84, 86, 88).
16. A bed (10) as claimed in claim 15, wherein the base (12) or mattress (14) comprises a layered structure of independently inflatable portions (84, 86, 88), each comprising a drop-stitch core (50).
17. A bed (10) as claimed in claim 15 or claim 16, wherein the layers (84, 86, 88) are layered horizontally in use.
18. A bed (10) as claimed in claim 15, 16 or 17, wherein the layers (84, 86, 88) each comprise an inflation valve (74).
19. A bed (10) as claimed in claim 15, 16 or 17, wherein a first layer (84) comprises a pressure-actuated diverter valve (74), which changes depending on the internal air pressure of the first chamber (84), such that when the internal air pressure within the first chamber (84) is below a threshold value, the air from the pump (90) is used to inflate the first chamber (84), but as the internal air pressure (92) increases, diverter valve (74) moves to a second position in which air from the pump (90) is diverted to an inlet (94) of a second chamber (86).
20. A bed (10) as claimed in claim 19, wherein as the diverter valve (74) moves to a second position, and outlet (99) leading to the first chamber (84) is sealed off.
21. A bed (10) as claimed in claim 19 or claim 20, wherein the second chamber (84, 86) comprises a pressure-actuated diverter valve (97) whereby as the pressure (92) within the second chamber (84, 86) exceeds a threshold value, the diverter valve (97) moves to a position whereby the air is diverted via a pilot line (76) to a pressure switch (98) configured to switch off the pump (90).
22. A bed (10) as claimed in any preceding claim, further comprising means for affixing the mattress (14) to the base (12).
23. A bed (10) as claimed in claim 22, wherein the means for affixing the mattress (14) to the base (12) comprises a strap (30).
24. A bed (10) as claimed in claim 23, wherein the strap (30) is length-adjustable, and comprises a quick-release buckle, clip or clasp arrangement.
25. A bed (10) as claimed in any of claims 22 to 24, wherein the means for affixing the mattress (14) to the base (12) comprises a hook and loop type fastener (40, 28) interposed between the mattress (14) and the base (12).
26. A bed (10) as claimed in any preceding claim, further comprising means (36) for separating a portion of the mattress (14) from the base (12).
27. A bed (10) as claimed in claim 26, wherein the means (36) for separating a portion of the mattress (14) from the base (12) comprises an inflatable insert (36) which can be inserted, in use, between the mattress (14) and the base (12).
28. A bed (10) as claimed in any preceding claim, further comprising an air pump (90).
29. A bed (10) as claimed in claim 29, wherein the air pump (90) comprises a remote control unit (148).
30. A bed (10) as claimed in claim 28 or claim 29, wherein the air pump (90) is selectively connectable, in use, via tubes (144) to any one or more of: the base (12); the mattress (14); and an insert (36).
31. A bed (10) according to any preceding claim, further comprising a transfer structure (120) comprising a planar support platform (122, 124) comprising castors (132) for supporting the transfer structure (120) above floor level (16).
32. A bed (10) as claimed in claim 31, wherein the transfer structure (120) is foldable.
33. A bed (10) as claimed in claim 31 or claim 32, wherein the transfer structure (120) comprises feet (130) located outwardly of the support platform (122, 124).
34. A bed (10) as claimed in claim 33, wherein the feet (130) comprise through holes for receiving mounting pins of lockable the castors (132).
35. A bed (10) as claimed in any of claims 31 to 34, wherein the transfer structure (120) comprises a cranked brace (134) for carrying the force of a load applied to the structure (120) when in an unfolded configuration.
36. A bed (10) as claimed in any of claims 31 to 35, wherein planar board support surface (124) comprises ball transfer units.
37. A bed (10) as claimed in any of claims 31 to 36, further comprising a support pole (150) locatable, in use, in a through hole of a foot (130).
38. A bariatric bed (10) according to any preceding claim.
39. A hospital bed (10) according to any preceding claim.
40. A surgical table (10) according to any preceding claim.
41. A bed, bariatric bed, hospital bed or surgical table substantially as hereinbefore described, with reference to, and as illustrated in the accompanying drawings.Amendments to the claims have been filed as follows Claims: 1. A bed (10) comprising a pneumatic base (12) and a pneumatic mattress (14), wherein the base (12) comprises a drop-stitch core (50) and wherein the mattress (14) comprises a drop-stitch core (50).2. Abed (10) as claimed in claim 1, wherein the drop-stitch core (50) comprises an upper sheet of flexible material (52), a lower sheet of flexible material (54) and space yarns (56) interconnecting the upper (52) and lower (54) flexible sheets.3. A bed (10) as claimed in claim 2, wherein the space yarns (56) are of substantially equal lengths and which are substantially evenly distributed across the surfaces of the upper (52) and lower (54) sheets.4. A bed (10) as claimed in any preceding claim, wherein the drop-stitch core (50) is surrounded by LI') a resiliently deformable foam layer (58).5. A bed (10) as claimed in any preceding claim, wherein the drop-stitch core (50) is surrounded by an airtight wrapper (60).6. A bed (10) as claimed in claim 5, wherein the wrapper (60) comprises planar upper and lower sheets (62), which overlie and underlie the drop-stitch core (50), respectively, and a sidewall (64) that extends round the sides of the core (50), and wherein the upper and lower sheets (62) and the sidewall (64) are sealingly affixed to one another to form an airtight seal.7. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a removable protective cover (70).8. A bed (10) as claimed in claim 7, wherein the cover (70) is manufactured from rip-stop fabric and comprises a zip fastener (72) to permit the cover (70) to be removed.9. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises an air inflation valve (74).10. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a pilot line (76) communicating with the interior of the core (50).11. A bed (10) as claimed in any preceding claim, wherein the base (12) or mattress (14) comprises a plurality of chambers.12. A bed (10) as claimed in claim 11, comprising an inner chamber (80) surrounded by a peripheral chamber (82).13. A bed (10) as claimed in claim 12, wherein the peripheral chamber (82) comprises a drop-stitch core (50) and wherein the inner chamber (80) comprises an air-cell.14. A bed (10) as claimed in claim 13, wherein the base (12) or mattress (14) comprises a layered 0 structure of independently inflatable portions (84, 86, 88).O 15. A bed (10) as claimed in claim 14, wherein the base (12) or mattress (14) comprises a layered structure of independently inflatable portions (84, 86, 88), each comprising a drop-stitch core (50).16. A bed (10) as claimed in claim 14 or claim 15, wherein the layers (84, 86, 88) are layered horizontally in use.17. A bed (10) as claimed in claim 14, 15 or 16, wherein the layers (84, 86, 88) each comprise an inflation valve (74).18. A bed (10) as claimed in claim 14, 15 or 16, wherein a first layer (84) comprises a pressure-actuated diverter valve (74), which changes depending on the internal air pressure of the first chamber (84), such that when the internal air pressure within the first chamber (84) is below a threshold value, the air from the pump (90) is used to inflate the first chamber (84), but as the internal air pressure (92) increases, diverter valve (74) moves to a second position in which air from the pump (90) is diverted to an inlet (94) of a second chamber (86).19. A bed (10) as claimed in claim 18, wherein as the diverter valve (74) moves to a second position, and outlet (99) leading to the first chamber (84) is sealed off.20. A bed (10) as claimed in claim 18 or claim 19, wherein the second chamber (84, 86) comprises a pressure-actuated diverter valve (97) whereby as the pressure (92) within the second chamber (84, 86) exceeds a threshold value, the diverter valve (97) moves to a position whereby the air is diverted via a pilot line (76) to a pressure switch (98) configured to switch off the pump (90).21. A bed (10) as claimed in any preceding claim, further comprising means for affixing the mattress (14) to the base (12).L.C) 22. A bed (10) as claimed in claim 21, wherein the means for affixing the mattress (14) to the base (12) comprises a strap (30).23. A bed (10) as claimed in claim 22, wherein the strap (30) is length-adjustable, and comprises a quick-release buckle, clip or clasp arrangement.24. A bed (10) as claimed in any of claims 21 to 23, wherein the means for affixing the mattress (14) to the base (12) comprises a hook and loop type fastener (40, 28) interposed between the mattress (14) and the base (12).25. A bed (10) as claimed in any preceding claim, further comprising means (36) for separating a portion of the mattress (14) from the base (12).26. A bed (10) as claimed in claim 25, wherein the means (36) for separating a portion of the mattress (14) from the base (12) comprises an inflatable insert (36) which can be inserted, in use, between the mattress (14) and the base (12).27. A bed (10)as claimed in any preceding claim, further comprising an air pump (90).28. A bed (10) as claimed in claim 28, wherein the air pump (90) comprises a remote control unit (148).29. A bed (10) as claimed in claim 27 or claim 28, wherein the air pump (90) is selectively connectable, in use, via tubes (144) to any one or more of: the base (12); the mattress (14); and an insert (36).30. A bed (10) according to any preceding claim, further comprising a transfer structure (120) comprising a planar support platform (122, 124) comprising castors (132) for supporting the LI') transfer structure (120) above floor level (16).31. A bed (10) as claimed in claim 30, wherein the transfer structure (120) is foldable.32. A bed (10) as claimed in claim 30 or claim 31, wherein the transfer structure (120) comprises feet (130) located outwardly of the support platform (122, 124).33. A bed (10) as claimed in claim 32, wherein the feet (130) comprise through holes for receiving mounting pins of lockable the castors (132).34. A bed (10) as claimed in any of claims 30 to 33, wherein the transfer structure (120) comprises a cranked brace (134) for carrying the force of a load applied to the structure (120) when in an unfolded configuration.35. A bed (10) as claimed in any of claims 30 to 34, wherein planar board support surface (124) comprises ball transfer units.36. A bed (10) as claimed in any of claims 30 to 35, further comprising a support pole (150) locatable) in use, in a through hole of a foot (130).37. A bariatric bed (10) according to any preceding claim.38. A hospital bed (10) according to any preceding claim.39. A surgical table (10) according to any preceding claim.40. A bed, bariatric bed, hospital bed or surgical table substantially as hereinbefore described) with reference to, and as illustrated in the accompanying drawings. LtD aD