FIELD OF THE INVENTION This invention relates to mattress configurations and methods of manufacture of mattress configurations. In particular, although not exclusively, the invention relates to the primary resilient member or a mattress core of a mattress.

BACKGROUND TO THE INVENTION

Various types of mattress core for a mattress are known. One common type is an 'inner-sprung' mattress that comprises an assembly of interlinked metal compression springs arranged inside the mattress to provide the appropriate resilience when housed within appropriate coverings. A problem with inner-sprung mattresses is the tendency of the springs to influence each other when deflected and this can result in sleeping partner disturbance, along with the cost and complexity of manufacture.

A 'pocket spring' mattress is another type of mattress core that addresses some of the problems associated with the inner-sprung mattress core. In a pocket spring mattress the springs sit independently of each other in individual textile pockets.

Another type of mattress core is known as a 'foam spring type' mattress core such as that described in New Zealand patent 330983, the contents of which is incorporated herein in its entirety. A foam spring type mattress core comprises a resilient member such as a foam blank or core having a plurality of apertures or bores therein which house metal compression springs.

In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. SUMMARY OF THE INVENTION

It is an object of this invention to provide an improved mattress or mattress core and/or method of manufacture, or to at least provide the public with a useful choice.

In a first aspect, the invention may broadly consist of a mattress comprising: a first layer comprising a block of resilient material having a plurality of bores within which resilient elements are provided; a second layer comprising a block of resilient material that is directly or indirectly fixed to the underside of the first layer, at least one dimension of the second layer being greater than the corresponding dimension of the first layer such that the second layer provides a peripheral support ledge or ledges extending outwardly relative to the perimeter of the first layer about at least a portion of the perimeter of the first layer; and one or more resilient side reinforcement components provided on the support ledge or ledges of the second layer that are at least fixed to respective portions of adjacent side peripheral surfaces of the first layer.

In an embodiment, the peripheral support ledge or ledges of the second layer extend below and outwardly relative to the perimeter of the first layer. In one form, upper surfaces of the peripheral support ledges are substantially co-incident or aligned in height with a lower surface of the first layer.

In an embodiment, at least a portion of the side surfaces of the resilient side reinforcement components are fixed to at least a portion of the abutting side peripheral surface of the first layer.

In an embodiment, at least a portion of the underside surfaces of the one or more resilient side reinforcement components are also fixed to at least a portion of their respective abutting support ledge or ledges of the second layer.

In an embodiment, the length and/or width of the second layer is greater than the corresponding length and/or width of the first layer. In an embodiment, the surface area of the second layer defined by its length and width dimensions is greater than the surface area of the first layer defined by its corresponding length and width dimensions.

In an embodiment, the non-overlapping portion of the second layer with the first layer represents the peripheral support ledge.

In an embodiment, the first layer is fixed centrally relative to the second layer to provide a peripheral support ledge that has either a uniform in width about the entire periphery of the first layer, or such that the ledge portions at the sides of the first layer have a uniform width and the ledge portions at the top and bottom ends of the upper layer have a uniform width. In an embodiment, the peripheral support ledge of the second layer extends continuously about the entire periphery of the first layer. In this embodiment, the one or more side reinforcement components extend about the entire periphery of the first layer resting upon the peripheral support edge of the second layer. In an embodiment, the side reinforcement components are in the form of elongate side rails situated upon the peripheral support ledge of the second layer. In one embodiment, there is a single side rail provided on each of the side and end peripheral support ledge portions. In another embodiment, there are two or more side rails provided end-to-end on each side and/or end peripheral support ledge portions.

In an embodiment, the bores of the first layer are enclosed. In one form, the bores of the first layer are enclosed on upper and lower surfaces of the first layer by enclosing or containment material layers being fixed or attached to both the upper and lower surfaces of the resilient block of the first layer. In this form, the enclosing material fixed or attached to the lower surface is located between the lower surface of the resilient block of the first layer and upper surface of the resilient block of the second layer. In another form, the bores are enclosed at an upper surface of the first layer by an enclosing material layer being fixed or attached to the upper surface of the resilient block of the first layer, and the bores are enclosed at a lower surface of the first layer directly by the upper surface of the resilient block of the second layer being fixed directly to the underside or lower surface of the resilient block of the first layer.

In one form, the enclosing material layers of the first layer may be selected from any one of the following: a felt pad, woven or mesh sheet material, or laminated sheet material. In one embodiment, the enclosing material layer(s) of the first layer may extend or protrude beyond the peripheral edge of the first layer such that they can be fixed or attached to at least a portion of respective upper and lower surfaces of the side reinforcement components. In another embodiment, the enclosing material layer(s) of the first layer may terminate at or toward the peripheral edges of the upper and lower surfaces of the first layer such that they do not contact the side reinforcement components.

In an embodiment, the lower enclosing material layer of the first layer may protrude beyond the peripheral edge of the first layer onto the peripheral support ledge of the second layer, but terminating prior to the peripheral edge of the second layer to leave a portion of the peripheral support ledge exposed. In one configuration, the lower surface of the side reinforcement components is attached or fixed to at least a portion of the protruding lower enclosing material layer of the first layer and at least a portion of the exposed peripheral support ledge provided by the second layer.

In an embodiment, the side reinforcement components are fixed or adhered to both the side peripheral surfaces of the first layer and at least a portion of peripheral support ledge of the second layer. In an embodiment, the mattress core is single-sided in that the first layer is closer to the intended end user surface of the mattress relative to the second layer. In an embodiment, the blocks of resilient material of the first and second layers are foam. In one form, the blocks of resilient material of the first and second layers is formed from any one of the following: foamed polyurethane, foamed polyethylene, or foamed latex rubber.

In an embodiment, the block of resilient material of the second layer is solid.

In an embodiment, the resilient side reinforcement components are formed of foam. In an embodiment, the resilient side reinforcement components are formed from any one of the following: foamed polyurethane, foamed polyethylene, or foamed latex rubber.

In one embodiment, the bores in the block of resilient material of the first layer are uniformly spaced relative to each other across the block of resilient material or within zones. In an alternative embodiment, the bores may be non-uniformly spaced or may be configured in zones or groupings where the intra-zone spacing is uniform, but the inter- zone spacing varies to provide customized posturisation in the mattress to the end user or groups of end users.

In some embodiments the spacing between bores within zones may be uniform with respect to the inter-bore spacing in the both width direction and length direction of the mattress. In other embodiments, the bores within a zone may have a first uniform inter- bore spacing with respect to the length direction of the mattress, and a second different uniform inter-bore spacing with respect to the width direction of the mattress. In some embodiments, the inter-bore spacing with respect to the length direction of the mattress may be uniform across the zones, but the inter-bore spacing with respect to the width direction may vary depending on the zone.

In one embodiment, there are multiple zones of bores in the first layer, each zone extending across the width of the first layer. The zones may be arranged in rows with respect to the length direction of the first layer. In one embodiment, the zones alternative between a close (or dense) inter-bore spacing to a wider (or less dense) inter- bore spacing. In one embodiment, there are at least three zones and more preferably at least five zones, and the denser zones are located at both the top or head end, and bottom or foot end of the bed. In one embodiment, the thickness of the blocks of resilient material of the first and second layers is substantially equal. In another embodiment, the thickness of the blocks of resilient material of the first and second layers may be different.

In an embodiment, the thickness of the resilient block of the first layer is preferably in the range of approximately 50mm to approximately 300mm, more preferably in the range of approximately 80mm to approximately 120mm, and even more preferably approximately 100mm.

In an embodiment, the thickness of the resilient block of the second layer is preferably in the range of approximately 50mm to approximately 300mm, more preferably in the range of approximately 80mm to approximately 120mm, and even more preferably approximately 100mm.

In an embodiment, the height of the side reinforcement components is substantially equal to the thickness of the resilient block of the first layer such that the upper surfaces of the side reinforcement components and resilient block of the first layer are substantially flush with each other.

In an embodiment, the resilient material of the second layer has a higher density than the resilient material of the first layer.

In an embodiment, the side reinforcement components have a higher density than the resilient material of the first layer. In an embodiment, the density of the resilient side reinforcement component is higher than the density of the resilient materials of both of the first and second layers. In an embodiment, the hardness of the resilient material of the second layer is higher than the hardness of the resilient material of the first layer.

In an embodiment, the hardness of the resilient side reinforcement components is higher than the hardness of the resilient material of the first layer. In an embodiment, the hardness of the resilient side reinforcement components is higher than the hardness of the resilient materials of both of the first and second layers.

In an embodiment, the density of the resilient material of the first layer, second layer and side reinforcement components is in the range of approximately 10kg/m ³ to approximately 40kg/m ³ .

In an embodiment, the density of the resilient material of the first layer is preferably in the range of approximately 10kg/m ³ to approximately 20kg/m ³ , more preferably approximately 15kg/m ³ to approximately 17kg/m ³ , and even more preferably approximately 16kg/m ³ .

In an embodiment, the density of the resilient material of the second layer is in the range of approximately 16kg/m ³ to approximately 40kg/m ³ , and more preferably approximately 20kg/m ³ to approximately 27kg/m ³ , and even more preferably approximately 23kg/m ³ .

In an embodiment, the density of the resilient side reinforcement components is in the range of approximately lOkg/m ³ to approximately 35kg/m ³ , more preferably approximately 25kg/m ³ to approximately 30kg/m ³ , and even more preferably approximately 27kg/m ³ .

In an embodiment, the hardness of the resilient material of the first layer, second layer and side reinforcement components is in the range of approximately 30N to approximately 300N. In an embodiment, the hardness of the resilient material of the first layer is in the range of approximately 70N to approximately HON, more preferably approximately 85N to approximately 95N, even more preferably approximately 90N. In an embodiment, the hardness of the resilient material of the second layer is in the range of approximately 160N to approximately 200N, more preferably in the range of approximately 175N to approximately 185N, and even more preferably approximately 180N. In an embodiment, the hardness of the resilient side reinforcement components is in the range of approximately 260N to approximately 300N, more preferably approximately 275N to approximately 285N, and even more preferably approximately 280N.

In an embodiment, the bores of in the block of resilient material of the first layer are cylindrical apertures.

In an embodiment, the resilient elements enclosed within the bores of the resilient material of the first layer are metal spring elements (springs). In one form, the springelements are helically wound and have an uncompressed height that is larger than the height of the spring element when compressed in-situ within its enclosed bore. In one form, the spring element are in a compressed form when enclosed within their respective bores. In an embodiment, the height of the spring elements relative to their compression axis is compressed by approximately 15% to approximately 20%, and more preferably approximately 17%, relative to the uncompressed height of the spring.

In an embodiment, the gauge of the spring elements is in the range of approximately 1.2mm to approximately 2.4mm, more preferably in the range of approximately 1.85mm to approximately 1.95mm. In an embodiment, the ratio of the uncompressed spring element height to bore height is approximately 1.18: 1 to approximately 1.25: 1, and more preferably approximately 1.2: 1. In an embodiment, the number of turns in the spring elements is in the range of approximately 5 turns to approximately 7 turns, and more preferably approximately 6 turns.

In an embodiment, the first layer, second layer, and side reinforcement components define a mattress core of the mattress. In an embodiment the mattress core may comprise one or more additional finishing or comfort layers. In one embodiment, the mattress further comprises a finishing layer that is fixed to the upper surface of the first layer. In one embodiment, the finishing layer may be a resilient foam block that is typically thinner than either or both of the resilient blocks of the first and second layers. In some embodiments, the thickness of the finishing layer is preferably in the range of approximately 10% to approximately 30% of the thickness of the first layer, more preferably in the range of approximately 15% to approximately 25%) of the thickness of the first layer, and even more preferably approximately 20% of the thickness of the first layer.

In an embodiment, the density and/or hardness of the finishing layer is greater than the resilient block of the first layer, but is also typically less than that of the resilient block of the second layer and/or side reinforcement components.

In some embodiments, the density of the finishing layer is preferably in the range of approximately 10kg/m ³ to approximately 30kg/m ³ , more preferably approximately 15kg/m ³ to approximately 25kg/m ³ , and even more preferably approximately 20kg/m ³ .

In some embodiments, the hardness of the finishing layer is preferably in the range of approximately 80N to approximately 120N, more preferably approximately 90N to approximately HON, and even more preferably approximately 100N.

In a second aspect, the present invention broadly consists of a method of manufacturing a mattress, comprising: providing or forming a first layer comprising a block of resilient material having a plurality of bores within which resilient elements are provided or received; fixing or securing a second layer comprising a block of resilient material to the underside of the first layer, at least one dimension of the second layer being greater than the corresponding dimension of the first layer such that the second layer provides a peripheral support ledge or ledges extending below and outwardly relative to the perimeter of the first layer about at least a portion of the perimeter of the first layer; and providing one or more resilient side reinforcement components on the support ledge or ledges of the second layer by fixing or securing the side reinforcement components at least to respective portions of the side peripheral surface of the first layer.

In one embodiment, providing or forming a first layer comprising a block of resilient material having a plurality of bores within which resilient elements are provided comprises providing a first layer in which the bores are enclosed at both ends at the upper and lower surfaces of the block of resilient material with resilient elements installed therein before fixing or securing the second layer to the first layer. In one such embodiment, providing or forming a first layer comprising a block of resilient material having a plurality of bores within which resilient elements are provided or received comprises: boring a plurality of bores through a block of resilient material defining the first layer; blinding or enclosing the bores on the lower surface or underside of the block of resilient material of the first layer by fixing or securing an enclosing material layer to the lower or underside surface of the resilient block of the first layer; inserting or installing resilient elements into respective bores of the block of resilient material; and blinding or enclosing the bores on the upper surface of the resilient block of material by fixing or securing an enclosing material layer to the upper surface of the block of resilient material.

In another embodiment, providing or forming a first layer comprising a block of resilient material having a plurality of bores within which resilient elements are provided or received comprises: providing a first layer comprising a resilient block of material with open-ended bores; securing or fixing the second layer to the underside of the first layer to blind the bottom end of the bores; inserting or installing resilient elements into the open top end of respective bores of the block of resilient material of the first layer; and blinding or enclosing the top end of the bores on the upper surface of the resilient block of material by fixing or securing an enclosing layer to the upper surface of the block of resilient material of the first layer. In an embodiment, the method further comprises securing or fixing the underside surface of the side reinforcement rails to at least a respective portion of the support ledge upon which they are provided.

In an embodiment, the method further comprises securing or fixing at least a portion of the upper and/or lower surfaces of the side reinforcement components to protruding portions of the respective upper and/or lower enclosing material layers of the first layer.

The second aspect of the invention may comprise any one or more of the features mentioned in respect of the first aspect of the invention.

The term "hardness" as used in this specification and claims is intended to mean, unless the context suggests otherwise, a measure or unit for measuring foam hardness, and in this specification the hardness measures or specifications have a unit measure in Newtons (N) determined in accordance with Australian Standard AS2282.8, which uses an 8-inch diameter indenter to push down the test piece to 40% deflection of the foam test piece thickness (which is 50mm thick), and the force reading is taken at that deflection as Newtons of force (N).

The term "comprising" as used in this specification and claims means "consisting at least in part of. When interpreting each statement in this specification and claims that includes the term "comprising", features other than that or those prefaced by the term may also be present. Related terms such as "comprise" and "comprises" are to be interpreted in the same manner. Number Ranges

It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner.

As used herein the term "and/or" means "and" or "or", or both. As used herein "(s)" following a noun means the plural and/or singular forms of the noun.

The invention consists in the foregoing and also envisages constructions of which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described by way of example only and with reference to the drawings, in which:

Figure 1 is a schematic perspective view of a mattress core in accordance with the embodiment of the mattress, but with a portion of the side rail components cut-away or omitted for clarity;

Figure 2 is a cross-sectional view of the mattress core through line A-A above figure 1 but also including an upper enclosing material layer and finishing layer;

Figure 2b is a schematic view of a spring component of figure 2a in an uncompressed form;

Figure 3 is a schematic perspective view of a mattress core in accordance with another embodiment of the mattress; and

Figure 4 is a schematic perspective view of a mattress core in accordance with another embodiment of the mattress. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Overview

The invention relates to a mattress, more particularly to the primary resilient member or mattress core of a mattress. Referring to Figure 1, the mattress core 10 comprises a first or upper resilient layer 12 of the foam spring type that is fixed or secured to a second or lower resilient layer 14 being larger in at least one of its length or width dimensions relative to the first layer 12 so as to provide a peripheral support ledge 14e extending about at least a portion of the perimeter of the upper layer 12. Resilient side reinforcing components 16 are provided on the support ledge 14e about at least a portion of the periphery of the upper layer 12. The combination of these components synergistically work together to provide a graduated feel from pressure relief to support.

Embodiments of each of the components of the mattress will be explained in further detail below.

First or upper layer of mattress core— spring housing

Referring to Figures l-2b, the resilient upper layer 12 of the mattress core is of the 'foam spring type' and will be explained in further detail. For example, the upper layer 12 comprises a block of resilient material such as foam. By way of example only, the foam block may be foamed polyurethane or polyethylene or foamed latex rubber. In this embodiment the resilient foam block is rectangular in profile and extends between first and second ends 12a, 12b and sides 12c,12d, and provides an upper surface 12f and lower surface 12g that are separated by the thickness of the resilient block 12. The width Wl of the resilient block is defined by the distance between the sides 12c, 12d of the block and the length LI of resilient block is defined by the distance between the ends 12a, 12b of the block. The thickness HI of resilient block is defined by the distance between its upper and lower surfaces 12f, 12g. In this embodiment, the thickness of the resilient block of the upper layer 12 is preferably in the range of approximately 50mm to approximately 300mm, more preferably in the range of approximately 80mm to approximately 120mm, and even more preferably approximately 100mm.

In this embodiment, the resilient block of the upper layer 12 is provided with a plurality of bores 18. In this embodiment, the bores are cylindrical through-bores extending through the thickness of the resilient block and being open at both ends at the upper 12f and lower surfaces 12g of the resilient block. The bores 18 form cylindrical apertures for housing respective resilient elements 20. In this embodiment, at least some and typically all of the bores 18 house or comprise a resilient element 20. In this embodiment, the resilient elements are typically metal spring components such as, but not limited to, helical metal springs. The spring components may for example be cylindrical in shape. In this embodiment, the resilient block of the upper layer functions as a 'spring housing' for the spring elements 20. The diameter of the cylindrical bores 18 is slightly larger than the diameter of the cylindrical spring elements 20 so that the spring elements sit snugly in their respective bores. The characteristics of the spring elements 20 are selected to work synergistically with the resilient block (spring housing). By way of example, characteristics of the spring elements such as the wire gauge, number of turns, and height are selected to work with the characteristics of the resilient block to provide an optimum mattress core.

In some embodiments, the gauge of the metal springs is in the range of approximately 1.2mm to approximately 2.4mm, more preferably in the range of approximately 1.85mm to approximately 1.95mm. In some embodiments, the ratio of the uncompressed spring height to bore height is approximately 1.18: 1 to approximately 1.25: 1, and more preferably approximately 1.2: 1. In some embodiments, the number of turns in the spring elements is in the range of approximately 5 turns to approximately 7 turns, and more preferably approximately 6 turns. In this embodiment, the bore holes 18 have a diameter of 57mm, and have a depth corresponding to the thickness HI of the resilient block of the upper layer 12, as they are through-holes. In this embodiment, the corresponding spring elements 20 have a wire gauge of 1.95mm, diameter or width of 55mm, and an uncompressed height that is greater than the depth of the bore holes 18 such that the spring elements are held under compression when in-situ within the bores 18 of the resilient block as explained further below. For example, in one embodiment, if the height of the bores and thickness of the resilient block of the upper layer 12 is approximately 100mm, the uncompressed height of the spring elements may be approximately 120mm.

In this embodiment, the bores 18 are blinded or enclosed at each end of the upper and lower surfaces 12f, 12g of the resilient block so as to retain or house the spring components within their respective bores. In this embodiment, the upper 12f and lower surfaces 12g of the resilient block of the upper layer 12 are provided with an enclosing material 22,24 that is fixed, attached or adhered to these surfaces to enclose the bores 18. By way of example, the upper and lower enclosing materials 22,24 may be felt pads or other sheet materials such as a woven, mesh or laminated materials for example. In one embodiment, the enclosing material layers 22,24 may be large enough to cover all bores and may terminate at or toward the peripheral edge of the resilient block of the upper layer 12. In another embodiment, the enclosing material layers 22,24 may be larger than the surface area of the upper surface 12f of the resilient block of the upper layer 12 such that they protrude beyond its peripheral edge. In one such embodiment, the upper and lower enclosing material layers 22,24 may extend beyond the peripheral edge of the upper layer but terminate prior to the boundary of the mattress core defined by the peripheral edge of the lower layer 14. In one such example, the enclosing material layers may terminate approximately half-way between the peripheral edge of the upper layer 12 and boundary of the mattress core defined by the lower layer 14. In another embodiment, the enclosing material layers may extend to the peripheral boundary of the mattress core as defined by the width and length of the lower layer 14.

In alternative embodiments, it will be appreciated that the upper or lower ends of the bores 18 may alternatively be enclosed or blinded directly by other layers of the mattress core or final mattress product. For example, in one alternative embodiment the lower layer 14 of the mattress core 10 may be directly fixed, adhered or secured to the lower surface 12g of the resilient block of the upper layer 12 to blind or enclose to the lower end of the bores 18, and/or likewise the upper end of the bores may be enclosed or blinded directly by one or more comfort layers 26 directly fixed, secured or adhered to the upper surface 12f of the resilient block of the upper layer 12. In such alternative embodiments, either or both of the enclosing material layers 22, 24 may be omitted.

In this embodiment, the resilient components 20 are configured to be held under compression or in a compressed state relative to their rest or un-compressed state. For example, Figure 2b shows a spring element 20 in an un-compressed state relative to its compressed state in-situ (shown in Figure 2a) within a bore 18 of the resilient block or spring housing of the upper layer 12. In one form, the upper layer 12 is configured such that the height of the in-situ spring elements without any loading on the mattress core is compressed by in the range of approximately 15% to approximately 20% relative to the height of the spring in an un-compressed or rest state. In one embodiment, the in-situ spring elements are held within the spring housing of the upper layer 12 with approximately 17% compression relative to their rest state.

In this embodiment, the density of the resilient block of the upper layer 12 is in the range of approximately 10kg/m ³ to approximately 40kg/m3. In some embodiments, the density of the resilient block is preferably in the range of approximately 10kg/m ³ to approximately 20kg/m ³ , more preferably approximately 15kg/m ³ to approximately 17kg/m ³ , and even more preferably approximately 16kg/m ³ .

In this embodiment, the hardness of the resilient block of the upper layer 12 is in the range of approximately 3 ON to approximately 300N. In some embodiments, the hardness of the resilient block is preferably in the range of approximately 70N to approximately HON, more preferably approximately 85N to approximately 95N, and even more preferably approximately 90N.

In the embodiment shown in Figures 1-2B, the bores 18 and their spring elements are uniformly spaced across the surface of the resilient block of the upper layer 12. For example, the bores 18 may be arranged in rows along the length of the resilient block. The uniform spacing between the bores is typically selected to be in the range of approximately 50mm to 300mm. In alternative embodiments, the bores may be non- uniformly spaced so as to vary the resilience characteristics of the mattress to suit dimensional and/or physical characteristics of users or groups of users, or general comfort requirements. In some such embodiments, the bores may be grouped into zones or regions having particular resilience characteristics. For example, Figure 3 shows an alternative mattress core 100 (like reference numerals represent like components) having non-uniform spring spacing. In this embodiment, zones 18a and 18c at the upper and lower ends of the mattress have a lower density of springs per surface area unit, such as by having spring elements with a wider spacing relative to each other to reduce the resilience of those regions in use and allow for greater deflection to reduce pressure on those parts of the user's body contacting those zones. In zones 18a and 18c, greater reliance is placed on the resilience of the foam block. In contrast, zone 18b has a higher density of spring elements, such as by having spring elements with a closer spacing between spring elements to provide greater resilient bias and less deflection of the mattress in that zone, and in such zones there is a greater reliance placed upon the spring elements. It will be appreciated that there may be any number of different zones. The zones may have a uniform inter-spring spacing, but the inter-spring spacing may vary compared to other zones in the mattress. In other words, the mattress may be configured with a uniform intra-zone spring spacing, but a non- uniform or varying inter-zone spring spacing.

As noted above, the upper layer 12 of the mattress core 10 may be of the 'spring foam type', which is generally described in New Zealand patents 330983 and 517967, which are herein incorporated by reference in their entirety. In some embodiments, the 'spring foam type' layer may be formed or manufactured using the techniques described in NZ330983 or NZ517967 as will be appreciated by a skilled person, although other techniques may alternatively be used.

Second or lower layer of mattress core— foam support core

Referring to Figures l-2b, the resilient lower layer 14 of the mattress core 10 comprises a block of resilient material such as foam. In this embodiment, the resilient block of the lower layer 14 acts as a foam support core for the foam spring type upper layer 12. The foam block may be foamed polyurethane or polyethylene or foamed latex rubber for example. In this embodiment, the resilient block of the lower layer 14 is a monolithic and solid foam block having a rectangular profile and extends between first and second ends 14a, 14b and sides 14c,14d, and provides an upper surface 14f and lower surface 14g that are separated by the thickness of the resilient block. The width W2 of the resilient block is defined as the distance between the sides 14c, 14d of the block, and the length L2 of the resilient block is defined as the distance between the ends 14a, 14b of the block. The thickness H2 of the resilient block is defined by the distance between its upper and lower surfaces 14f,14g.

The length L2 and width W2 of the resilient block of the lower layer 14 defines the overall length and width dimensions of the mattress core 10 and/or overall mattress that the mattress core forms part of. As previously explained, the resilient block of the upper layer 12 is fixed or secured, directly or indirectly, to the resilient block of the lower layer 14. In particular, the lower surface 12g of the upper layer 12 is fixed or secured, directly or indirectly, to the upper surface 14f of the lower layer 14. In the embodiment of Figure 2a, the resilient block of the upper layer 12 comprises a lower enclosing material layer 24, such as a felt pad, and in this embodiment the upper surface 14f of the lower layer 14 is fixed or secured to the lower enclosing material layer 24 of the upper layer. In alternative embodiments, the lower enclosing layer 24 may be omitted and the upper surface 14f of the resilient block of the lower layer 14 may be directly fixed to lower surface 12g of the resilient block of the upper layer 12. The layers 12, 14 may be fixed to each other via any suitable fixing means such as, but not limited to, via adhesive or welding (e.g. radiofrequency or ultrasonic welding).

In this embodiment, the cross-sectional area of the upper surface of the lower layer 14 is larger than the cross-sectional area of the lower surface of the upper layer 12 such that a peripheral support ledge 14e is provided about at least a portion or portions of the periphery of the upper layer 12. By way of example, at least one of the length L2 or width W2 dimensions of the resilient block of the lower layer 14 is greater than the corresponding length LI or width Wl dimensions of the resilient block of the upper layer 12 such that a portion of the lower layer 14 protrudes beyond the upper layer 12 to thereby provide a peripheral support ledge about at least a portion or portions of the periphery below the upper layer 12. In the preferred embodiment shown, both the length and width dimensions of the lower layer 14 are greater than the corresponding dimensions of the upper layer 12 such that the peripheral support ledge extends around the entire periphery of the upper layer 12 of the mattress core. In this embodiment, the width of the support ledge 14e is uniform about the periphery of the mattress core, although it will be appreciated that the width of the ledge may be varied if desired. For example, in other embodiments, the width of the side ledge portions along the sides of the mattress core may be different to the width of the top and bottom ledge portions along the top and bottom ends of the mattress core.

As will be explained in further detail below, the support ledge or ledges 14e provided by the larger lower layer 14 relative to the upper layer 12, provide a support surface upon which peripheral or side reinforcement components or rails 16 may be installed or fixed about the periphery of the upper layer 12.

In this embodiment, the thickness H2 of the resilient block of the lower layer 14 is approximately the same as the thickness HI of the resilient block of the upper layer 12, although this may be varied in alternative embodiments. In this embodiment, the thickness of the resilient block of the lower layer 14 is preferably in the range of approximately 50mm to approximately 300mm, more preferably in the range of approximately 80mm to approximately 120mm, and even more preferably approximately 100mm.

In this embodiment, the density and/or hardness of the resilient block of the lower layer 14 is greater than that of the resilient block of the upper layer 12. In one embodiment, the resilient block of the lower layer 14 is both denser and harder than the resilient block of the upper layer 12. In a preferred embodiment, the density and/or hardness of the resilient block of the lower layer 14 is greater than the density and/or hardness of the resilient block of the upper layer 12, but less than the density and/or hardness of the side reinforcement components or side rails 16.

In this embodiment, the density of the resilient block of the lower layer 14 is in the range of approximately lOkg/m ³ to approximately 40kg/m ³ . In one form, the density of the resilient material of the second layer is in the range of approximately 16kg/m ³ to approximately 40kg/m ³ , and more preferably approximately 20kg/m ³ to approximately 27kg/m ³ , and even more preferably approximately 23kg/m ³ . In this embodiment, the hardness of the resilient block of the lower layer 14 is in the range of approximately 3 ON to approximately 300N. In one form, the hardness of the resilient material of the lower layer 14 is in the range of approximately 160N to approximately 200N, more preferably in the range of approximately 175N to approximately 185N, and even more preferably approximately 180N.

Side reinforcement components— side rails

Referring to Figures l-2b, the resilient side reinforcement components 16, also referred to herein as 'side rails', are formed of resilient material such as foam. In this embodiment, the side rails may be formed of foamed polyurethane or polyethylene or foamed latex rubber for example. In this embodiment, the side rails 16 are monolithic and solid foam elongate rails having a rectangular cross-section.

The side rails 16 are located about the portions of the periphery of the upper layer 12 that have corresponding associated support ledge 14e portions provided by the lower layer 14. In a preferred embodiment, the peripheral support ledge 14e is continuous and extends about the entire periphery of the upper layer 12 such that the side rails 16 extend about the entire periphery of the upper layer 12. Each elongate ledge portion 14e corresponding to a side or end of the mattress core may be provided with either a single side rail or a plurality of elongate side rails arranged end-to-end along the side or end ledge. In such forms, the side rails abut in the corners of the mattress core to form an overall continuous side rail about the periphery of the mattress core. Figure 1 shows a single side rail 16 per side or end of the mattress core (although a portion of two rails is omitted or cut-away in the drawing to show the inner layers for clarity).

It will be appreciated that in alternative embodiments, the side rails need not necessarily be individual elongate components and could be pre-formed as a single or integral continuous frame-like component that is then fixed or secured upon the peripheral support ledge 14e.

Referring to Figure 2A, in this embodiment the inner side surface 16a of the side rails 16 are fixed or secured at least to the abutting vertical side periphery surface 12h of the upper layer 12 and also at least a portion of the lower surface 16b is fixed or secured directly to a portion of the surface of the peripheral support ledge 14e supporting the side rail. In this embodiment, at least a portion of the lower surface 16b of the rail is also fixed or secured directly to the protruding portion of the lower enclosing material layer 24 of the upper layer 12. In alternative embodiments, the lower enclosing material layer 24 may not protrude beyond the edge of the resilient block of the upper layer 12 or may be omitted entirely, and in such embodiments the lower surface 16b of the rail is directly fixed or secured only to the surface of the support ledge 14e. In this embodiment, at least an inner portion of the upper surface 16c of the sides rails 16 are fixed or secured to the underside of the protruding upper enclosing material layer 22 of the upper layer 12, with the remaining outer portion of the upper surface 16c of the side rail being fixable or securable to an underside portion of a comfort layer 26 provided upon the mattress core 10. In other alternative embodiments, the upper and lower enclosing material layers 24,26 may protrude right to the peripheral edge of the mattress core defined by the peripheral edge of the lower layer 14, and in such embodiments, the lower 16b and upper 16c surfaces of the rails may be fixed or secured entirely to the protruding portions of the enclosing material layers 24,26.

If one or more elongate side rails are being used about the periphery, the abutting end surfaces of the side rails may also be adhered or otherwise fixed to any adjacent abutting surface of adjacent side rails. For example, where there are four side rails used, one for each peripheral ledge at the sides, top and bottom of the mattress core, the side rails may be adhered to each other at the mating or abutting surfaces where they meet in the corners of the mattress core.

The surfaces of the side rails 16 that are secured or fixed to other surfaces or components of the mattress core as described above may be via any suitable fixing means such as, but not limited to, adhesive or welding (e.g. radiofrequency or ultrasonic welding).

In the embodiment shown in Figures 1-2B, the side rails 16 are dimensioned so as to substantially fill the peripheral cavity provided about the upper layer 12 by virtue of the protruding peripheral ledge 14e of the lower layer 14, such that the overall mattress core 10 shape has a substantially rectangular form. For example, the width W3 of the side rails 16 is configured to be substantially equal to the corresponding width of the peripheral ledge 14e supporting it, and the height H3 of the side rails 16 is configured to be substantially equal to the thickness HI of the resilient block of the upper layer 12. In this configuration the upper surface 16c of the side rails 16 is substantially flush with the adjacent upper surface 12f of the resilient block of the upper layer 12.

In this embodiment, the density and/or hardness of the side rails 16 is greater than that of the resilient block of the upper layer 12. In one embodiment, both the density and hardness of the side rails 16 is greater than that of the resilient block of the upper layer 12. In this embodiment, the density and/or hardness of the side rails 16 is also greater than or equal to that of the resilient block of the lower layer 14.

In this embodiment, the density of the resilient side rails is in the range of approximately 10kg/m ³ to approximately 40kg/m3. In some embodiments, the density of the resilient side rails 16 is in the range of approximately 10kg/m ³ to approximately 35kg/m ³ , more preferably approximately 25kg/m ³ to approximately 30kg/m ³ , and even more preferably approximately 27kg/m ³ . In this embodiment, the hardness of the resilient side rails 16 is in the range of approximately 3 ON to approximately 300N. In some embodiments, the hardness of the resilient side rails 16 is preferably in the range of approximately 260N to approximately 300N, more preferably approximately 275N to 285N, and even more preferably approximately 280N.

Additional finishing or comfort layers

In one embodiment, the mattress may comprise only the mattress core 10. In alternative embodiments, the mattress may comprise the mattress core and one or more additional mattress or comfort layers fixed or provided on top of the mattress core, such that the mattress core functions as the primary resilient element or core to an overall mattress configuration. It will be appreciated that there are endless variations of different comfort layers that may be provided on top of the mattress core to form the overall mattress. The mattress would typically be supported on a mattress base or slatted bed frame for example.

By way of example, the embodiment of Figure 2 A shows the mattress core 10 being provided with a resilient finishing layer 26 that is fixed or secured on top of the upper layer 12. In this embodiment, the finishing layer 26 is a resilient foam block that is typically thinner than either or both of the resilient blocks of the upper 12 and lower 14 layers. In some embodiments, the thickness of the finishing layer 26 is preferably in the range of approximately 10% to approximately 30% of the thickness of the upper layer 12, more preferably in the range of approximately 15% to approximately 25% of the thickness of the upper layer, and even more preferably approximately 20% of the thickness of the upper layer.

In one embodiment, the density and/or hardness of the finishing layer 26 is greater than the resilient block of the upper layer 12, but is also typically less than that of the resilient block of the lower layer 14 and/or side rails 16. In some embodiments, the density of the finishing layer 26 is preferably in the range of approximately lOkg/m ³ to approximately 30kg/m ³ , more preferably approximately 15kg/m ³ to approximately 25kg/m ³ , and even more preferably approximately 20kg/m ³ . In some embodiments, the hardness of the finishing layer 26 is preferably in the range of approximately 80N to approximately 120N, more preferably approximately 90N to approximately HON, and even more preferably approximately 100N.

Combination of components— interrelationship aspects

In at least some embodiments, the mattress core 10 comprising the combination of the lower resilient foam block layer 14 (foam support core), upper spring foam type layer 12 (spring housing), and resilient side rails supported on the peripheral ledge 14e provided by the lower layer 14 have a synergistic relationship that generates a unique mattress core. The higher density and hardness of the foam in the foam support core of the lower layer 14, relative to the support provided by the combination of the springs and foam in the spring housing upper layer 12, generates a graduated feel profile of initial comfort and then support.

Method of manufacture

By way of example only, the method of manufacturing the mattress core 10 of the embodiment shown in Figures 1-2 A will be described. It will be appreciated that the steps in the method may be varied or altered in alternative embodiments.

In one embodiment, the method of manufacturing or assembling the mattress core comprises providing the upper spring foam type layer 12. In one example, this is typically achieved by providing the a solid resilient foam block of the upper layer 12, boring or otherwise forming the bores 18 through the foam block in the desired pattern, whether uniform or zoned, such as by using a CNC boring machine or similar. The lower enclosing material layer 24, e.g. felt pad, is then adhered or otherwise secured to the underside surface of the bored foam block to blind or enclose the lower ends of the bores. The spring elements 20 are then inserted or installed into respective bores 18, and then the top end of the bores are enclosed by an upper enclosing material layer 22 being adhered or otherwise being secured to the upper surface of the foam block to close or blind the top end of the bores. This process provides the spring foam type upper layer 12. It will be appreciated that the foam spring type upper layer 12 may also be formed or manufactured using the techniques described in NZ330983 or NZ517967 as will be appreciated by a skilled person, although other techniques may alternatively be used.

The foam block of the lower layer 14 is then provided at the required dimensions relative to the upper spring foam type layer 12. The upper surface 14f of the foam block of the lower layer 14 is then adhered or otherwise fixed to the underside surface of the spring foam type layer 12, which in this embodiment is the surface of the lower enclosing material layer 24. The upper layer 12 is typically secured centrally to the larger lower layer 14 relative to the length and width dimensions of the mattress core so as to provide a peripheral support ledge 14e that is uniform in width at least with respect to the top and bottom ledge portions, and side ledge portions, or more preferably the ledge 14e has a uniform width around the entire periphery of the upper layer 12.

The resilient side rail components 16 are then adhered or otherwise fixed onto the peripheral support ledge 14e of the lower layer 14 about the periphery of the upper layer 12 to generate the assembled mattress core. Having a support ledge 14e assists in allowing easier installation of the side rails 16 about the periphery of the upper layer 12 as they are supported from below during the fixing process. As previously described, the inner side surfaces 16a of the side rails are typically adhered to the adjacent or abutting side peripheral surface of the foam block of the upper layer 12. The lower surface 16b of the rails is adhered to the support ledge 14e and/or any protruding lower enclosing material layer 24 of the upper layer. The upper surface 16c of the side rails 16 may be adhered or otherwise fixed to the underside of any protruding upper enclosing material layer 22 of the upper layer 12, or alternatively may be left exposed in the mattress core and available for fixing or adhering to any one or more additional finishing or comfort layers 26 that are secured or provided on top of the mattress core. If one or more elongate side rails are being used about the periphery, the abutting end surfaces of the side rails may also be adhered or otherwise fixed to any adjacent abutting surface of adjacent side rails.

In alternative embodiments, the upper layer 12 may not be enclosed by a lower enclosing material layer 24, but rather directly adhered or secured to the foam block of the lower layer. In such embodiments, after the foam block of the upper layer is bored, it is then adhered or secured to the foam block of the lower layer 14 to thereby enclose or blind the bottom ends of the bores 18, ready for the insertion or installation of the spring elements 20 into the open top bores 18. The upper enclosing layer 22 is then installed onto the upper surface of the upper layer after the spring installation as before to enclose the top end of the bores and to secure or retain the springs within their respective bores. The side rails 16 are then installed as noted above to generate the assembled mattress core 10. In either of the above approaches, the mattress core may then have one or more additional finishing or comfort layers of foam or other materials or coverings secured or applied to the mattress core to provide the overall mattress.

It will be appreciated that the fixing of the various components (such as the foam components) together may be by adhering, such as with spray or spot-applied adhesive to one or both surfaces to be adhered or the application or use of double-sided adhesive tape, welding, or any other suitable fixing or securing method known to a skilled person. Example embodiment of one preferred mattress core

By way of example only, one preferred specification for the mattress core 10 will be explained below in further detail. The width and length dimensions of the mattress core may be selected to suit different typical sizes. The length is typically approximately 2030mm but could be varied as desired, and the width could be any of the following standard widths or size chart:

• Long single - approximately 910mm

• King single - approximately 1070mm • Double - approximately 1370mm

• Queen - approximately 1530mm

• King - approximately 1670mm

• Super King - approximately 1830mm

· California King - approximately 2000mm

The upper layer 12 comprises a foam block having a density of approximately 16kg/m ³ and hardness of approximately 90N. The thickness HI of the foam block is approximately 100mm. The length LI of the foam block is approximately 2030mm less the width of two side rails (160mm). The width Wl of the foam block is the selected mattress size from the size chart less the width of two side rails (160mm). The bore holes 18 are cylindrical with a diameter of approximately 57mm and depth of approximately 100mm. The spring elements 20 have a wire gauge of approximately 1.95mm, approximately 6 turns, are cylindrical in shape with a diameter of approximately 55mm, and an uncompressed or rest height of 120mm.

The lower layer 14 comprises a foam block having a density of approximately 26kg/m3 and hardness of approximately 180N. The thickness H2 of the foam block is approximately 100mm. The length L2 of the foam block is approximately 2030mm. The width W2 of the foam block is selected according to the mattress size from the size chart.

The side rails 16 are elongate foam elements having a rectangular cross-sectional profile. The side rails 16 have a width W3 of approximately 80mm and a height H3 of approximately 100mm. In this example embodiment mattress core, there are four side rails, one for each of the ledges at the sides, and top and bottom ends of the mattress core. In this embodiment, the side rails for the side ledges have a length corresponding to the length L2 of the lower layer 14, so approximately 2030mm. The side rails for the top and bottom ledges have a length corresponding to the width Wl of the upper layer 12, so in this case corresponds to the width size selected from the size chart less the width of two side rails (160mm). In an alternative form, the side rails for the side ledges may have a length corresponding to the length LI of the upper layer, and the side rails for the top and bottom ledges may have a length corresponding to the width W2 of the lower layer 14.

Referring to Figure 4, an example of a zoning profile for the bores 18 of the upper layer 12 is shown. This zoning profile is provided by a multi-headed CNC boring machine, such as a 4-headed boring machine. It will be appreciated that the bore density (i.e. number of bores per square unit area or defined by the inter-bore spacing) corresponds to the resulting spring density, as each bore encloses a spring. In this example, the zoning profile comprises five zones, each extending across the width (W) of the mattress. The zones are provided in rows relative to the length (L) direction or dimension of the mattress. In this example, the zones 180a-180e alternate between dense and less dense in terms of the inter-bore spacing (or number of bores per square unit area). In this example, the top 180e, bottom 180a, and middle zone 180c are denser zones, and the remaining zones 180b and 180d are less dense in that the inter-bore spacing of those zones is larger with respect to at least one direction or dimension. In this example, the zones are configured such that the inter-bore spacing in the length (L) direction is substantially uniform across the mattress. However, the different inter-bore spacing of the zones is generated by a variance in the inter-bore spacing with respect to the width (W) direction of the mattress. In particular, the 4-head CNC boring machine is set or configured to have a larger offset or displacement in the width direction between drilling each successive set of 4-bores in zones 180b and 180d, relative to the other zones 180a, 180c, 180e having a higher bore density. In this example, the inter-bore spacing (i.e. distance between adjacent edges) in the length direction of the bores across the mattress is approximately 30.5mm. The inter-bore spacing in the width direction of denser zones 180a, 180c, and 180e is approximately 17.5mm (with center-to-center spacing of approximately 75.5mm), and in the less dense zones 180b and 180d is approximately 25.9mm (with center-to-center spacing of approximately 83mm).

The above specification provides, by way of example only, one preferred mattress core specification of the mattress configuration that provides a graduated feel from pressure relief to support. The spring characteristics, comprising the gauge, number of turns, and uncompressed height, provide an optimum blend that works synergistically with the characteristics and specifications of the surround foam block spring housing of the upper layer 12. Further the upper layer 12 works optimally with the specifications and characteristics of the lower layer 14 to provide the graduated feel from pressure relief to support because neither the foam blocks nor the springs are under full compression with the above combination of specifications.

The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.