FIELD OF THE INVENTION

[00011 The invention relates to an inflatable mattress. The invention is particularly suited to a mattress for use on cold surfaces.

BACKGROUND TO THE INVENTION

[0002] The following discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known or part of the common general knowledge in any jurisdiction as at the priority date of the application,

[0003J Camping and related activities are enjoyed by a large number of people. Some of these people enjoy these activities in cold environments (such as tops of mountains or the polar regions). If these people are not appropriately attired or equipped for such environments the environment can act to sap them of their body heat. In extreme situations, this loss of body heat may threaten the person's life.

[0004] One wa of preventing this from occurring when the person is camping overnight is to take a camping mattress. The camping mattress is then set up and the person's sleeping bag placed thereon. This means that the camping mattress operates as the thermal insulator between the person (in their sleeping bag) and the cold ground.

[0005] At the sam time, as the camping mattress is required to be transported by the person to these cold environment locations - which are often remote - the camping mattress must be lightweight.

[0006] With these two requirements in mind, the most common form of construction of camping mattresses is to use large tubular or prismatic air chambers. These air chambers are filled with an insulating materia!. To provide further insulating properties, the air chambers are often contain a heat reflective layer.

[0007] It is at this point that air mattresses may differ.

[0008] Some camping mattresses fix the position of the insulating material and heat reflective layer. In this version, the stresses resulting from the stretching that occurs during inflation and/or allocation of user load can damage the typically delicate construction of these materials, if this occurs, pieces of the insulation materia! can break free and clump together at random locations impeding the even distribution of the insulating material throughout the camping mattress. The impact of such stresses on the heat reflective layer can also cause it to break into pieces further degrading the insulating properties of the camping mattress.

[00093 Other camping mattresses leave the insulating material and heat reflective layer as free floating elements within th air chambers. However, this also poses problems in that this material can clump together in random sections of the air chamber due to repeated packing/unpacking of the camping mattress (in addition to its general use). Where this occurs, a situation again exists where the even distribution of the insulating material throughout the camping mattress is impeded.

[00103 It is therefore an object of the present invention to provide an improved air mattress that eliminates, or ameliorates at least in part, one or more of the aforementioned problems.

SUMMARY OF THE INVENTION

[00113 Throughout this document, unless otherwise indicated to the contrary, the terms "comprising", "consisting of", and the like, are to be construed as non- exhaustive, or in other words, as meaning "including, but not limited to".

[00123 In accordance with a first aspect of the present invention there is an inflatable mattress comprising:

• an upper sheet of material;

• a lower sheet of material; and

• at least one layer of insulating material positioned between the upper sheet and lower sheet having preformed apertures provided therein; where, the upper sheet is press connected to the lower sheet of material at at least one position corresponding with a preformed aperture, the press connections operating to define a plurality of inflatable ceils and retain a portion of the insulating materia! in each inflatable cell. [00133 The inflatable mattress may comprise a further layer of heat reflective material, the layer of heat reflective material being positioned between the upper sheet and the at least one layer of insulating material.

[0014] The insulating cells are preferably arranged in rows, the insulating cells of a first row being offset relative to the insulating cells of its adjacent rows.

[001 SJ In accordance with a second aspect of the invention there is a inflatable mattress comprising:

• a first inflatable layer comprising the area defined by a first sheet of material and an intermediate sheet of material;

• a second inflatable layer comprising the area defined by the intermediate sheet of material and a second sheet of material; and

• at least one layer of insulating material provided in the first inflatable layer, the layer of insulating material having preformed apertures provided therein; where, the first sheet is press connected to the intermediate sheet of material at at least one position corresponding with a preformed aperture, so as to define a plurality of inflatable cells in the first inflatable layer and the second sheet is press connected to the intermediate sheet of material to define a plurality of inflatable cells in the second inflatable layer, such that a portion of the insulating material is retained in each inflatable cell of the first layer.

[0016] A layer of heat reflective material may be provided in the first inflatable layer, the layer of heat reflective material being positioned between the intermediate sheet of material and the at least one layer of insulating material. Furthermore, the second inflatable layer may also include at least one layer of insulating material.

[0017] The insulating cells in each inflatable layer can be arranged in rows, the insulating cells of a first row being offset relative to the insulating cells of its adjacent rows. In its most preferred arrangement, the insulating cells in the first inflatable layer are further offset relative to its adjacent insulating cells in the second inflatable layer.

[0018] A pair of air inlet valves may be used such that air passing through one air inlet valve operates to inflate the inflatable cells of the first inflatable layer while air that passes through the other air inlet valve operates to inflate the inflatable cells of the second inflatable layer. [001θ| accordance with a third aspect of the invention there is an inflatable mattress comprising: a first and third portion constructed in accordance with the first aspect of the invention;

a second portion, interposed between the first and third portion, constructed in accordance with the second aspect of the invention;

where inflation of the inf!atabie ceils of the first portion causes inflation of the inflatable ceils in the second portion and inflation of the inflatable ceils in the third portion causes inflation of the inflatable cells in the second portion.

[0020] Preferably, the first portion represents the area where an average user's head would be positioned when the user lies upon the mattress, the second portion represents the area where th user's torso would be positioned when the user lies upon the mattress and the third portion represents the area where an average user's legs would be positioned when the user lies upon the mattress,

[00213 Preferably, the inflatable mattress of any aspect of the invention operates such that inflation of each inflatable cell also causes lofting in the portion of insulating material retained in that inflatable cell. To assist in this occurring, the at least one layer of insulating material is preferably made from a material is able to compress under force and expand when the force is removed.

[0022] The press connection may be formed from any one of the following: a dot weld; a detachable press stud; a tubular connection; a baffle wall.

[0023] Similarly, at least one layer of insulating material is made from a latticed material and/or the inflatable cells are diamond shaped.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an air mattress according to a first embodiment of the invention.

Figure 2 is a perspective view of an air mattress according to a second embodiment of the invention. Figure 3 is a cross-sectional view of the air mattress shown in Figure 2 as taken along axis B-B.

Figure 4 is a cross-sectional view of the air mattress shown in Figure 1 as taken along axis A-A.

Figure 5 is a cross-sectional view of an air mattress according to a third embodiment of the invention.

Figure 6 is art exploded view of layers of the air mattress shown in Figure 1. Figure 7 is an exploded view of layers of the air mattress shown in Figure 2. Figure 8 is an exploded view of layers of the air mattress shown in Figure 5. Figures 9a and 9b are cross-sectional views of an air mattress incorporating PREFERRED EMBODIMENTS OF THE INVENTION

[00253 In accordance with a first embodiment of the invention there is an inflatable mattress 10. In this first embodiment, the inflatable mattress 10 comprises a single inflatable layer 12 formed from an upper sheet of material 14 and a lower sheet of material 16.

[0026] The single inflatable layer 12 is constructed so as to comprise a plurality of small inflatable cells 18 arranged in to sequential lines 20.

[0027] Each inflatable cell 18 is delineated by four dot welds 22 arranged in a diamond pattern. The dot welds 22 connect the upper sheet of material 14 to the lower sheet of material 16. The dot welds 22 are grouped into N-S dot welds 22a and E-W dot welds 22b. The dot welds 22 operate to space each inflatable cell 18 from the next inflatable cell 18 in the sequential line 20,

[0028] Each sequential line 20 of inflatable cells 18 is offset from its adjacent sequential lines 20. This arrangement means that the N-S dot welds 22a of a first inflatable cell 18 also acts as E-W dot welds 22b of the two inflatable cells 18 in each of its adjacent sequential lines 20.

[0029] The inflatable cells 18 that are at the periphery of the inflatable mattress 10 have their periphery edges 24 sealed. [0030] Prior to formation of the dot welds 22, a layer of latticed insulating material 26 and a layer of heat reflective material 28 is placed between the upper and lower sheets of material 14, 16. Each layer 26, 28 has preformed apertures 30 provided therein. The preformed apertures 30 correspond with the intended position of each dot weld 22 to be formed. Thus, when the dot we!ds 22 are formed, they operate to secure each layer 26, 28 in place while still providing each layer 26, 28 with limited freedom to move as required. This, in turn, means that each inflatable cell 18 in effect has some latticed insulating material 26 and heat reflective materia! 28 contained therein.

[0031] Located at one end 32 of the inflatable mattress 10 is an air inlet valve

34. The air inlet valve 34 is in fluid communication with a first inflatable cell 18.

[0032] This first embodiment of the invention will now be described in the context of its intended use.

[0033] The inflatable mattress 10 is laid out in its deflated form on a cold surface 50. Laid out in this manner the air inlet valve 34 is easily accessible to a user (not shown).

[0034] The user then connects an air pump (also not shown) to the air inlet valve 34. Air forced through the air inlet valve 34 by the air pump enters the first inflatable cell 18. The forced air acts to inflate the first inflatable cell 18.

[0035] The inflation of any inflatable cell 18 creates openings 36 between the dot welds 22 into other inflatable ceils 18. These openings 36 allow the forced air to enter into the adjacent inflatable cells 18, thereby inflating these inflatable cells 18. This process repeats until all the inflatable ceils 18 are inflated.

[0036] At the same time, as each Inflatable cell 18 inflates, the change in height results in a correlating reduction in the area of contact between the air mattress 1 and the cold surface 50 (i.e. a lateral contraction in the size of the inflatable cell). Lateral contraction of the inflatable cell 18 causes a similar contracting force to be applied to the insulating material 26. The latticed nature of the insulating material 26 means that the combination of this application of this force and the reduction in compressive force that is applied to the insulating material 26 by the inflatable mattress 10 in its deflated form, results in the insulating materia! lofting 26 up in volume. This expansion in volume improves the insulating properties of the insulating material 26.

[0037] Note that as the insulating material layer 26 is made from a latticed material, the insulating material layer 26 does not impede the spread of the forced air through the inflatable cells 18.

[0038] Of course, when the inflatable ceils 18 at the periphery of the inflatable mattress 10 are inflated, the sealed periphery edges 24 prevent the air from escaping.

[0039] it is also to be noted that in a norma! inflatable mattress, the heat differential between the layer on which the user lies and the layer that connects with the cold surface creates a convectional air movement within the inflatable mattress. This movement of air results in a reasonably uniform distribution of heat throughout the inflatable mattress. This is not desirable, though, as it means that the heat is not focused on areas where the user contacts the inflatable mattress,

[0040] In this embodiment, this convectional air movement is disrupted by the inflatable cells 18. To elaborate, by dividing the inflatable mattress 10 into a series of inflatable cells 18, there is a first level of disruption to convectional air movement. A second level of disruption to convectional air movement is created by the presence of the lofted insulating material 26 itself. These two levels of disruption operate to constrain the distribution of heat about the air mattress 10 to primarily those areas where the heat source (i.e the user's body) is situated.

[0041] It is also to be noted that the layer of insulating material 26 also operates to disrupt the connective transfer of heat vertically from the heat source to the cold surface 50 in a manner as would be readily apparent to the person skilled in the art.

[0042] The key advantage of this invention is in the use of the insulating material layer 26 and the heat reflective layer 28. Due to the temperature differences between the cold surface 50 and the user (when laying on the mattress), in the absence of any insulating system the user's body heat will be readily absorbed by the cold surface 50. However, the presence and position of the heat reflective layer 26 as maintained by the constraining actions of the dot welds 22 results in some of the user's body heat being reflected back towards him/her rather than being absorbed by the cold surface 50. The users body heat not reflected back to the user is then partially absorbed by the insulating material layer 26 and thereby resists further heat loss to the cold ground 50.

[0043] Additionally, when deformation of the inflatable cells 18 occurs due to the pressure of the user's body weight, this causes situations where the dot welds 22 contact the cold surface 50. As there is no insulating material at the points of the dot weld 22, this means that there is still possible areas of the mattress where the user's body heat can be lost. However, the offset nature of the inflatable cells 18 between sequential lines 20 further restricts the possibility of the dot weld 22 actually contacting the cold surface 50.

[0044] In accordance with a second embodiment of the invention, where like numerals reference like parts, there is an inflatable mattress 100. In this second embodiment, the inflatable mattress 100 comprises a pair of inflatable layers 102a, 102b.

[0045] Inflatable layer 102a is formed of an upper sheet of materia! 104 and an intermediate sheet of materia! 106. Inflatable layer 102b is formed of an intermediate sheet of material 108 and a lower sheet, of material 108.

[0046] Each inflatable layer 102a, 102b comprises a plurality of inflatable cells

18 arranged in to sequential lines 20.

[0047] Each inflatable cell 18 is delineated by four dot welds 22 arranged in a diamond pattern. The dot welds 22 are grouped into N-S dot welds 22a and E-W dot welds 22b. The dot welds 22 operate to space each inflatable cell 18 from the next inflatable cell 22 in the sequential line 20.

[0048] As with the first embodiment, prior to formation of the dot welds 22 layers of heat reflective material 28 and insulating material 26 are applied. In the case of inflatable layer 102a, a layer of latticed insulating materia! 26 is placed between the upper sheet of material 104 and the intermediate sheet of material 106.

[0049] In the case of inflatable layer 102b, a layer of latticed insulating material 26 and a layer of heat reflective material 28 is placed between the intermediate sheet of material 106 and the lower sheet of materia! 108. The placement of these layers is such that the layer of latticed material 26 is adjacent the lower sheet of material 108, while the layer of heat reflective material 28 is adjacent the intermediate sheet of material 106.

[0050] Each layer 26, 28 has preformed apertures 30 provided therein. The preformed apertures 30 correspond with the intended position of each dot weld 22 to be formed. Thus _! when the dot welds 22 are formed, they operate to secure each layer 26, 28 in place while stili providing each layer 26, 28 with limited freedom to move as required. This, in turn, means that each inflatable cell 18 in effect has some latticed insulating material 26 and heat reflective material 28 contained therein.

[0051] in both inflatable layers 102a, 102b, each sequential line 20 of inflatable cells 18 is offset from its adjacent sequential lines 20. This arrangement means that the N-S dot welds 22a of a first inflatable cell 18 also acts as E-W dot welds 22b of the two inflatable cells 18 in each of its adjacent sequential lines 20.

[0052] in a similar fashion, the arrangement of inflatable cells 18 provided in inflatable layer 102a is offset relative to the inflatable cells 18 provided in inflatable layer 102b. This offset configuration means that each inflatable cell 18 in one inflatable layer 102 spans two inflatable cells 18 provided in the other inflatable layer 102. This is shown graphically in Figure 3.

[0053] The inflatable cells 18 that are at the periphery of each inflatable layer

102a, 102b have their periphery edges 24 sealed.

[0054] Located at one end 110 of the inflatable mattress 100 are a pair of air inlet valves 112. One of the air inlet valves 112 is in fluid communication with a first inflatable cell 18 of inflatable layer 102a. The other air inlet valve 112 is in fluid communication with a second inflatable cell 18 of inflatable layer 102b.

[0055] This second embodiment of the invention will! now be described in the context of its intended use.

[0056] The inflatable mattress 100 is laid out in its deflated form on a cold surface 50. Laid out in this manner at least one of the air inlet valves 112 is easily accessible to a user (not shown). For the purposes of this example, the accessible air inlet valve 112 is i fluid communication with the first inflatable cell 18 of inflatable layer [00573 The user then connects an air pump (also not shown) to the accessible air inlet valve 1 12. Air forced through the accessible air inlet valve 112 by the air pum enters the first inflatable eel! 8. The forced air acts to inflate the first inflatable cell 18.

[0058] The inflation of any inflatable cell 18 creates openings 36 between the dot welds 22 into other inflatable cells 18. These openings 36 allows the forced air to enter into the adjacent inflatable cells 18, thereby inflating these inflatable cells 18. This process repeats until all the inflatable cells 18 are inflated.

[0059J Of course, when the inflatable cells 18 at the periphery of the inflatable layer 102a are inflated, the sealed periphery edges 24 prevent the air from escaping.

[0060] As with the first embodiment, as each inflatable cell 18 inflates, the insulating material layer 28 is free to move to provide an appropriate distribution of insulation. While such movement is allowed, to prevent uneven distribution of the insulating material in the inflatable cells 18 - and across the inflatable mattress 10 as a whole - the dot welds 22 operate to limit the movement. This occurs even in situations where some of the preformed apertures 30 are ripped or torn .

[0061] With inflatable layer 102a inflated, the user then manipulates the inflatable mattress 100 to a position where the other air inlet valve 112 ma be accessed and connects the air pump thereto.

[0062] Air forced through this other air inlet valve 1 12 by the air pump enters the second inflatable cell 18 and inflates it. Inflation of this second inflatable ceil 18 and its adjacent cells is in an identical manner to that described for inflation of the first inflatable cell 18. This continues until inflatable layer 102b is also inflated.

[0063] Limited free movement is again given to the insulating material layer

26 and heat reflective layer 28 as previously described.

[0064] Note again that as the insulating material layers 26 are made from a latticed material, the forced air is not impeded as it spreads through any of the inflatable cells 18.

[0065] This arrangement offers multiple advantages over existing inflatable mattresses including: -π-

• The offset arrangement of inflatable cells 18 relative to each inflatable layer 102a, 102b means that there is no area of the inflatable mattress 100 that does not have some form of insulation separating the user (when laying on the mattress 100) from the cold surface 50.

• By providing two separate inflatable layers, the user can stiil retain some of the insulating advantages of the mattress 100 even when one of the inflatable layers 102 is deflated. This is particularly advantageous in situations where the cold surface 50 is dispersed with objects that may puncture the bottom-most inflatable layer 102.

• Additionally, the use of two separate inflatable layers allows the user to inflate the bottom-most inflatable layer 102 to its fully inflated position while varying the level of inflation of the top-most inflatable layer 102. This adjustment of the level of inflation of the top-most inflatable layer 102 means that the user can adjust the air mattress 100, as a whole, to match their own comfort requirements.

• In this embodiment, as each inflatable cell 18 has adjacent cells in the opposing layer 102a, 102b (as appropriate), the potential for loss of body heat resulting from dot welds 22 contacting the cold surface 50 is minimised, if not eliminated. This is because even if the dot weld 22 does contact the cold surface 50 (and noting that this may not occur as a result of the offset nature of the inflatable cells 18 between sequential lines 20), the dot weld 22 lies underneath an inflatable cell 18. Thus, there is at least one layer of insulating materia! 28 between the user and the cold surface 50 at all times.

[0066] In accordance with a third embodiment of the invention, where like numerals reference like parts, there is an inflatable mattress 200. The inflatable mattress 200 comprises an upper portion 202, a middle portion 204 and a lower portion 206.

[0067] in its preferred configuration, the upper portion 202 contains the area where a user's head is located during sleep, the middle portion 204 contains the area where the user's torso is iocated during sleep and the lower portion 206 contains the area where the user's legs are iocated during sleep. [00683 The upper portion 202 and lower portion 206 incorporate an insulated cell 18 construction and configuration as described in the first embodiment of the invention.

[0069] The middle portion 204 incorporates an insulated cell 18 construction and configuration as described in the second embodiment of the invention.

[0070] Because of the differing forms of construction used in the various portions, the layers of insulating material 26 and heat reflective material 28 are similarly portioned.

[0071] A key element of this third embodiment is that the upper, middle and lower portions 202, 204, 206 are inflated by way of a single air inlet valve 34. The air inlet valve 34 is in fluid communication with an inflatable cell 18 located in the upper portion 202.

[0072] This third embodiment of the invention will now be described in the context of its intended use.

[0073] The inflatable mattress 200 is laid out in its deflated form on a cold surface 50 such that the air inlet valve 34 is easily accessible to a user (not shown).

[0074] The user then connects an air pump (also not shown) to the air inlet valve 34. Air forced through the air iniet valve 34 by the air pump enters an inflatable cell 8 in the upper portion 202. The forced air acts to inflate this inflatable cell 18.

[0075] As with the other embodiments, the inflation of any inflatable cell 18 creates openings 36 between the dot welds 22 into other inflatable cells 18. These openings 36 allows the forced air to enter into the adjacent inflatable cells 18, thereby inflating these inflatable cells 18. This process repeats until all the inflatable cells 18 in the upper portion 202 are inflated.

[0076] When the inflatable cells 18 in the upper portion 202 that border the intermediate portion 204 ar inflated, openings 36 are then created into both inflatable layers 102a, 102b of the intermediate portion 204. This then allows the inflatable cells 18 in both inflatable layers 102a, 102b to inflate in a manner identical to that previously described. [00773 Onc the inflatable cells 18 in inflatable layers 102a, 102b have inflated, the air pushed through these inflatable cells 18 again combines to inflate the inflatable cells 18 provided in the lower portion 206.

[0078] As with the other embodiments, when the inflatable cells 18 at the external periphery of the air mattress 200 are inflated, the sealed periphery edges 24 prevent the air from escaping.

[0079] In all other respects, the various portions of this third embodiment act as per the first embodiment or second embodiment as appropriate. This allows the user to have the additional insulating benefits of the second embodiment at their torso where body heat is most readily lost, while retaining the lightweight characteristics of the first embodiment at the head and legs where such loss is likely to be of less consequence.

[0080] It should also be appreciated by the person skilled in the art that the above invention is not limited to the embodiment described. In particular, the following modifications and improvements may be made without departing from the scope of the present invention:

• Dot welds 22 ma be replaced by other mechanisms for defining the inflatable cells 18. For instance, pressed portions or detachable press studs may be used. The use of detachable press studs allows for the size of the inflatable cells 18 may be varied as desired by simply attaching only the relevant press studs.

• Alternatively, the pressed portions may take the form of a spacer element as illustrated in Figures 9a and 9b. When used in the second embodiment of the invention (or the part of the third embodiment of the invention that implements the second embodiment of the invention), the spacer element 300 operates to provide distance between the two inflatable layers 102a, 102b at the point of connection. Examples of spacer elements that can achieve this objective include a vertical tube and a baffle wall.

» While not preferred, the invention may be reconfigured so that a single layer of heat reflective material 28 or a single layer of insulating material 26 may be used.

• Alternatively, an additional layer of heat reflective material 28 may be incorporated into the insulating mattress 10, 100, 200. • The invention may use different, non-linear arrangements for the inflatable cells 18. Similarly, the inflatable cells 18 need not be arranged in a repetitive pattern.

• The inventio may use more or less dot welds to define the shape(s) of the inflatable cells 18, be they geometric or non-geometric. For instance, three dot welds may be used to define triangular shaped inflatable cells 18.

• The layer of insulating material 26 may be made from a non-latticed material. In such situations, it is important that the layer of insulating material 26 does not impede the openings 36 of each insulating ceil 18 when inflated. If this were to occur, the inflatable mattress 10, 100, 200 may have inflatable cells 18 in certain areas which do not inflate.

• In a variation of the second embodiment, inflatable layer 102a may simply contain a layer of insulating materia! 26 while inflatable layer 102b may simply contain a layer of heat reflective material 28.

• The inflatable mattress 10, 100, 200 may be subjected to an anti-microbial treatment to prevent mould or fungal growth. This allows the inflatable mattress 10, 100, 200 to be inflated by the user's breath rather than by way of an air pump.

• The air inlet valve 34, 108 is preferably of the type described in the applicant Sea to Summit's co-pending patent application published as PCT/AU2013/001158 titled "improved Valve for Inflatable Devices".

• The insulating material 26 is preferably the high loft insulation marketed by Invista of Kansas, USA under the trade mark "THERMOLITE". However, the insulating materia! 26 may be any material that has an expandable three- dimensional matrix with air spaces in its structure such as foam, a matting of elastic fibres or a collection of down feathers. The important characteristic of such material is that it must be able to compress under force and expand when the force is removed.

• The heat reflective layers 28 is preferably the non-woven fabric with a thin metalised layer applied to the surface marketed by Texland and Nexko Co., Ltd. of South Korea under the trade mark ΈΧΚΙΝ PLATINUM".

[0081] It should be further appreciated by the person skilled in the art that the above variations and modifications, not being mutualiy exclusive, can be combined to form yet further embodiments that fall within the scope of the present invention.