Patent Publication Number: US-2011047710-A1

Title: Mattress

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/AU2009/000281, filed Mar. 10, 2009. which claims the benefit of Australian Application No. 2008901189, filed Mar. 11, 2008, the entire disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a mattress, and a mattress cover therefor. 
     BACKGROUND OF THE INVENTION 
     The use of comfort layers in mattresses has arisen in recent years due to the comfortable support provided. Such comfort layers are typically formed of latex, visco-elastic foam or other flexible high density, high resilience foams. In the field of bedding, high density foams are usually regarded as those having a density of 20 to 100 kg/m 3 , with low density foams generally having a density of 10 to less than 20 kg/m 3 . In the context of the present specification, the term “high density” has this meaning High resilience foam grades are generally high density foams in which the cell structure has been broken down to form a generally “open cell” construction which is more resilient than the closed cell structure. 
     These comfort layers are typically provided above another, typically more resilient and harder, support layer to allow a person lying on the bed to sink into the comfort layer, distributing pressure more evenly across the person&#39;s body, while still retaining support from the underlying support layer. Visco-elastic foam support layers have gained particular popularity as a result of their temperature sensitivity whereby they become softer when heated by body heat and consequently generally mold to the form of the body, distributing pressure more evenly. Visco-elastic foam is also referred to as “memory foam”, and is generally a form of flexible polyurethane foam. 
     Visco-elastic foam and latex support layers, however, are generally unable to readily dissipate heat from the person&#39;s body and, given that there is generally a greater area of surface contact between the person&#39;s body and the molded upper surface of the mattress, mattresses with such comfort layers are often found to be uncomfortably hot to sleep on. 
     Mattress structures have previously been proposed that include a resilient, highly breathable spacer layer below the comfort layer to assist in dissipating heat from the comfort layer by maintaining an air space between the comfort layer and underlying support layer. Such a structure, however, relies on the heat dissipating through the thickness of the comfort layer prior to escaping via the spacer layer. 
     Mattress structures have also been proposed that utilize a spacer layer laminated to the top surface of the comfort layer in an effort to dissipate heat from the person&#39;s body prior to reaching the comfort layer. Such structures, however, do not provide for washability of the spacer layer and do not allow for retrofitting to existing mattresses with visco-elastic foam or latex comfort layers that have been found to be uncomfortable due to overheating. 
     BRIEF SUMMARY 
     A mattress cover is described which includes a sleep panel configured to cover an upper surface of a mattress body. The sleep panel includes an upper cover layer formed of a breathable fabric, a lower cover layer formed of a breathable fabric, and a resilient and highly breathable three-dimensional spacer layer disposed between said upper and lower cover layers. The upper cover layer, the spacer layer and the lower cover layer are secured by quilting or tufting. The mattress cover further includes a peripheral skirt extending about a periphery of the sleep panel for engaging side surfaces of the mattress body. In one form, the spacer layer includes a pair of spaced apart outer mesh elements interconnected by an array of spacer yarns extending between and separating the outer mesh elements. As one option, the spacer layer may be formed of an open-cell reticulated foam. As another option, the spacer layer is separated into multiple zones of varying resilience. 
     In another embodiment, a mattress is described which includes a mattress body and a mattress cover located over the mattress body with a sleep panel covering an upper surface of the mattress body. In this embodiment the mattress cover is constructed and arranged as described above. The mattress body includes a comfort layer disposed beneath the sleep panel and a resilient support layer disposed beneath the comfort layer. Typically, the comfort layer comprises a high density, high resilience foam. In particular embodiments, the comfort layer is formed of visco-elastic foam. Alternatively, the comfort layer may be formed of latex. 
     In yet another embodiment, a mattress is described which includes a resilient support layer, a resilient and highly breathable three-dimensional lower spacer layer disposed above the support layer, a comfort layer disposed above the lower spacer layer, a resilient and highly breathable three-dimensional upper spacer layer disposed above the comfort layer, and a breathable upper cover layer disposed above the upper spacer layer. The comfort layer having a plurality of perforations extending through a thickness thereof. 
     Typically, the comfort layer comprises a high density, high resilience foam. In particular embodiments, the comfort layer is formed of visco-elastic foam. Alternatively, the comfort layer may be formed of latex. 
     In one alternative form, the spacer layers each comprise a pair of spaced apart outer mesh elements interconnected by an array of spacer yarns sitting between and separating the outer mesh elements. 
     Alternatively, the spacer layers may be formed of an open-cell reticulated foam. 
     In one alternative form, the upper spacer layer is separated into multiple zones of varying resilience. 
     Typically, the lower spacer layer is laminated to the comfort layer. 
     OBJECT OF THE INVENTION 
     It is the object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages briefly mentioned in the Background. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Preferred embodiments of the present invention will now be described, by way of an example only, with reference to the accompanying drawings wherein: 
         FIG. 1  is an exploded view of a mattress. 
         FIG. 2  is a further exploded perspective view of  FIG. 1  with individual layers of each panel laminated. 
         FIG. 3  is a fragmentary cross-sectional view of the mattress of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the disclosure, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations and further modifications in the illustrated device and its use, and such further applications of the principles of the disclosure as illustrated therein being contemplated as would normally occur to one skilled in the art to which the disclosure relates. 
     Referring to the accompanying drawings, a mattress  1  comprises a base layer  2 , support layer  3 , intermediate panel  4 , and cover  5 . The cover  5  defines the upper face of the mattress  1  forming a sleep surface. The base layer  2  defines the lower face of the mattress which will typically be located on a mattress foundation. The support layer  3  and intermediate panel  4  together define the mattress body  6  and are located between the cover  5  and base layer  2 . 
     The cover  5  comprises a sleep panel  7  configured to cover the upper surface of the mattress body  6  and a peripheral skirt  8  extending about a periphery of the sleep panel  7  for engaging the side surfaces of the mattress body  6 . Referring specifically to  FIG. 3 , the sleep panel  7  comprises an upper cover layer  9  formed of a breathable fabric and a lower cover layer  10  also formed of a breathable fabric. The breathable fabric may be either knitted or woven and may, for example, be a stretchable velour fabric. A resilient and highly breathable three-dimensional upper spacer layer  12  is disposed between the upper and lower cover layers  9 ,  10 . The upper cover layer  9 , upper spacer layer  11  and lower cover layer  10  are secured together by quilting, so as to form a quilted sleep surface as depicted in  FIG. 1 . Alternatively, it is envisaged that the upper cover layer  9 , upper spacer layer  11  and lower cover layer  10  might be secured by tufting. 
     The upper spacer layer  11  is typically formed of a three dimensional fabric having a pair of spaced apart outer mesh elements interconnected by an array of spacer yarns (alternatively referred to as loop piles) extending between and separating the outer mesh elements. A particularly suitable three dimensional fabric for forming the spacer layer is Space Flex® spacer fabric manufactured by Pressless GmbH of Falkenau, Germany. The upper spacer layer  11  will typically have a thickness of about 15 to 40 mm. The upper spacer layer  11  may be separated into multiple zones of varying resilience by varying the spacing (or properties) of the spacer yarns in each zone. For example, a central zone extending laterally across the mattress, generally in the area of the torso of a person lying on the mattress, may be formed of a more resilient spacer layer, whilst the opposing head and leg ends of the mattress may be formed with a spacer layer of lower resilience. Accordingly, such a central zone would provide additional support to the heavier torso of the person&#39;s body. 
     As an alternative to the three dimensional fabric of the spacer layer, a breathable open-cell reticulated foam material may be utilized, as is available from Joyce Foam Products of Moorebank, New South Wales, Australia. 
     The peripheral skirt  8  is typically formed of a fabric material, conveniently the same material as the upper cover layer  9 . The upper edge of the skirt is stitched to the sleep panel  17 . The lower edge of the peripheral skirt  8  will typically be secured to the periphery of the base  2  by way of a zipper  12 . 
     The intermediate panel  4  here comprises a comfort layer  13  that is generally formed of a high density, high resilience foam. The comfort layer  13  may be formed of a flexible polyurethane foam. The flexible polyurethane foam may be a visco-elastic foam, typically having a density of between 40 and 100 kg/m 3 . Alternatively, the comfort layer  13  may be formed of other types of high resilience flexible polyurethane foam having a density of between 25 and 50 kg/m 3 . In other forms, the comfort layer  13  may be formed of latex, which may either be Talalay or Dunlop process latex (sometimes referred to as a latex foam). To improve the breathability of the comfort layer  13 , allowing any residual heat that has passed through the upper spacer layer  11  to pass through, a series of pin hole perforations  14  may be provided, extending through the thickness of the comfort layer  13 . The perforations  14  will generally be provided when the comfort layer  13  is formed of latex but they are also applicable to other compositions of comfort layer  13 . The comfort layer  13  will typically have a thickness of about 50 to 100 mm. 
     The intermediate panel  4  also includes a resilient and highly breathable three-dimensional lower spacer layer  15 . The lower spacer layer  15  will typically be laminated to the comfort layer  13 . The lower spacer layer  15  may be formed of the same material as the upper spacer layer  11 . The lower spacer layer  15  will typically have a thickness of about 10 to 30 mm. The lower spacer layer  15  enables any heat that has dissipated through the comfort layer  13  to be readily dissipated by maintaining an air layer separating the comfort layer  13  from the layers lying beneath. The lower spacer layer  15  may be configured as a firmer layer than the upper spacer layer  11 , so that the lower spacer layer  15  will contribute more to supporting a person lying on the mattress  1  while the upper spacer layer  11  will contribute more to comfort. In particular embodiments, the firmer lower spacer layer  15  may have a compressive elastic modulus of about 11 to 15 kPa, with the upper spacer layer  11  having a compressive elastic modulus of about 2 to 10 kPa. 
     The intermediate panel  4  will typically further comprise a lower layer  16  that is laminated to the underside of the lower spacer layer  15 . The lower layer  16  is typically formed of a high density flexible polyurethane foam having a density of about 25 to 50 kg/m 3 . The lower layer  16  will typically have a thickness of about 20 to 40 mm. The lower layer  16  provides a foundation for the lower spacer layer  15  and comfort layer  13  and adds both extra comfort and support. The lower layer  16  also generally confines the lower spacer layer  15 , which when configured as a spacer fabric can be a little coarse and may have its ends otherwise sticking through the skirt  8  of the cover  5 . 
     The support layer  3  is here formed of two separate support cores  17 ,  18  formed of high resilience flexible polyurethane foam having a density of about 25 to 50 kg/m 3 . The support cores  17 ,  18  may alternatively be formed of latex, such as Talalay process latex foam or Dunlop process latex. The support cores  17 ,  18  will typically each have a thickness of about 100 to 200 mm. The support cores  17 ,  18  may be configured with different hardness materials so as to provide different support on the two opposing sides of the mattress  1  to satisfy the desires of two individuals lying on the mattress. For example, one support core  17  may be configured with a particularly firm support core  17 , while the other support core  18  may be configured with a softer material. The support cores  17 ,  18  are not laminated to the lower layer  16  and as such may be readily replaced as desired if the firmness requirements of persons using the bed change over time. Forming the support cores  17 ,  18  separately also enables production of mattresses with varying hardness properties merely by utilizing varying hardness support cores. 
     The side surfaces of the mattress body  6  are defined by the edges of the support layer  3  and intermediate panel  4 . So as to maintain a neat side surface in the event that there is some minor relative displacement between the support layer  3  and intermediate panel  4 , additional foam elements may be located within the skirt  8  adjacent the edges of the mattress body  6 . The individual elements of the mattress body  6 , being the support cores  17 ,  18  and intermediate panel  4  may be covered in a dust-mite resistant barrier fabric so as to render the mattress  1  particularly suitable to asthma and other allergy sufferers. 
     The base layer  2  is typically formed of a fabric material and serves to enclose the mattress body  6  with the cover  5  that is secured to the base layer  2  by way of a zipper  12  as discussed above. 
     In use, heat generated by the body of a person lying on the mattress may firstly be dissipated by the air layer provided by the upper spacer layer  11 , separating the person&#39;s body from the comfort layer  13 . Whilst the upper spacer layer  11  provides for dissipation of heat, some residual heat is likely to penetrate through to the comfort layer  13 . The perforations  14  extending through the thickness of the comfort layer  13  provide passages for heat to dissipate through the thickness of the comfort layer  13  and then out of the mattress body  6  via the air gap provided by the lower spacer layer  15 . Embodying the upper spacer layer  11  within the sleep panel  7  of the cover  5  provides for removal and washing of the upper spacer layer  11  (within the cover  5 ). This structure also allows for retrofitting of the spacer layer  11  embodied within the cover  5 , to mattresses having visco-elastic foam or latex comfort layers that have previously been purchased, typically at significant expense, without the need to discard the mattress. 
     While the preferred embodiment of the invention has been illustrated and described in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that all changes and modifications that come within the spirit of the invention are desired to be protected.