MULTILAYER MATTRESS

Abstract: A mattress system is disclosed which permits the, or each, user to select readily the mattress firmness either for a single bed, or independently for each half of a bed to be used by two people. Regardless of the firmness chosen, the overall thickness is maintained constant. The mattress (11) comprises a plurality of foam mattress elements (12-16, 22-26), of different firmnesses, together with a substantially rigid core (17, 27) element; alteration of the sequence in the set changes the firmness. A two person mattress includes two sets of mattress elements. Additionally, a torso board can be included to provide a localized firmer surface. The system also provides an essentially smooth transition between two sets when used, for example, in a double bed.

Description: MULTILAYER MATTRESS This invention is concerned with a mattress and a combination system including the mattress for use on a bed frame which will provide the user, or users, with a choice of mattress firmness without disturbing the overall height of the sleeping surface from the floor. In the following discussion two terms are used to have meanings somewhat different to those commonly attributed to them. By a "single" bed, mattress, or the like, is meant a unit of a size commonly used by one person; thus, it can range upwardly from a crib or child's bed, at least to the size known in North America as twin (that is, up to about 1 meter in width and about 1.8 meters in length) . By a "double" bed, mattress, or the like, is meant a unit of a size commonly used by two persons; thus, it can range upwardly from the size known in North America as double (about 1.8 meters in width and about 2.1 meters in length) . Generally speaking, the hardness, or firmness, of a conventional bed comprising a mattress supported by a base is determined by the choice of materials made during the construction of each of the mattress and the base. Consequently, beds are available in which the firmness can vary at different points within a particular bed, and in which the overall firmness varies between separate beds. However, the only choice of firmness which a user can make with such a conventional bed or mattress is made when the bed or mattress is purchased. Thereafter, the user has little further choice, other than to replace the item. Choice on purchase is apparently simple, and is usually a matter of trial and error. Generally, the choice is made -1 - by sitting or lying briefly on the mattress, for example in a bedding store. This is not an adequate or very reliable test method. A further significant problem can arise if either a need is encountered to change the firmness of an existing bed (either temporarily or permanently) , or if two persons using a double bed require radically different firmnesses. For example, one person may require a very firm support for orthopaedic reasons, whilst the other may find such a level of firmness uncomfortable to the point that sleep is not possible. There are also problems of deflection transmission sideways across a bed, especially if one user is of significantly different weight to the other. This invention seeks to mitigate and to overcome these problems by providing a mattress for use on a bed frame support system in which the firmness can be chosen at will, even on a daily basis. Consequently, this invention seeks to provide a mattress for a single person in which the hardness can be changed, either temporarily or permanently, in response to a perceived need. Additionally, a mattress according to this invention can be maintained at a given level of firmness on an on-going basis over a period of time. Consequently, such a mattress is not subject to the loss of firmness encountered with a conventional mattress after an extended period of use. Further, this invention seeks to provide a mattress for two people which permits each person to select a desired level of firmness, and also to be able to change each persons' part of the mattress, either permanently or temporarily, in response to a perceived need. Furthermore, this aspect of the invention also seeks to provide a mattress for two people in which the top surface is always at the same height across its full width, regardless of the - 2 - firmness(es) selected, in which there is a smooth transition from one part of the mattress to the other, and also no significant intervening gap. It is known that by using various combinations of the currently available elastomeric foam materials (in the past, these were either natural or synthetic rubber; in more modern practice, polyurethanes are used) , a level of variation of firmness can be obtained. Thus Hood, in U.S. 3,118,153 describes an upholstery construction wherein corners are strengthened by using two layers of soft foam with a layer of harder foam in between them. Boyles, U.S. 3,534,417 applies similar concepts to a mattress, to provide some level of choice. A different level of firmness is obtained by turning over either the whole mattress, or an intermediate portion thereof extending across the full width of the bed. All of the mattress portions are enclosed within a common casing. Whilst this does give a flat sleeping surface, only a very limited number of choices of firmness are provided. Johnson, U.S. 2,121,339 describes a more complicated system. The mattress consists of two layers of foam of differing firmness with a hard board layer in between them. The firmness is changed by reversing the elements making up the mattress. Thus, although a constant thickness results, few choices of firmness are allowed. For a double bed, it appears that the whole surface would have to have the same firmness. A similar mattress utilizing two layers of dissimilar foam is described by Slemmons, U.S. 3,110,442. In this mattress, two stacked resilient members are used of different firmness, with a provision to insert firming slats, either at predetermined points, or more or less anywhere, across the width of the mattress. A mattress using a plurality of foam pad elements is described by Betten-Zellekens in German - 3 - 1,940,763. This mattress is somewhat similar to that described by Slemmons, in that a stiff, preferably plywood, panel is included into the stack. Thus, although a plurality of foam elements is used, the only way to adjust the firmness is to reposition the plywood insert within the stack. It has now been realized that a mattress can be provided which both provides a uniform and constant sleeping surface height at substantially the same level as a conventional bed, and yet which provides the, or each, user with a high degree of choice of firmness. Thus, in its broadest aspect, this invention provides a mattress comprising in combination an assembly of mattress components chosen from the group consisting of: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a plurality of first separation means, at least one of which is associated with each of the foam mattress elements, permitting each mattress element to compress and to flex separately; (iii) at least one lightweight substantially rigid core element of substantially the same length and width as at least one of the plurality of foam mattress elements; (iv) at least one second separation means between the rigid core element and the foam mattress elements permitting the foam mattress elements adjacent the core element to compress and to flex separately; - 4 - (v) a lightweight substantially stiff torso board, substantially smaller in width and length than at least one of the plurality of foam mattress elements; (vi) at least one surface element on the torso board constructed and adapted to retain the torso board in a chosen position in between two adjacent foam mattress elements, and (vii) a containment means adapted and constructed to ensure that the plurality of foam mattress elements remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements to slight lateral compression; provided that the mattress assembly includes at least components (i) and (ii) . Thus, in a first more detailed aspect, this invention provides a mattress which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a separation means between each of the mattress elements permitting each mattress element to compress and to flex separately; and (iii) a containment means adapted and constructed to ensure that the plurality of mattress elements remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements to slight lateral compression. - 5 - HEET In a second more detailed aspect, this invention provides a mattress which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a lightweight substantially rigid core element of substantially the same length and width as the foam mattress elements; (iii) a separation means between each of the mattress elements, and between the mattress elements and the rigid core element, permitting each mattress element to compress and to flex separately; and (iv) a containment means adapted and constructed to ensure that the plurality of mattress elements together with the core element remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements together with the core element to slight lateral compression. In a third more detailed aspect, this invention provides a mattress unit which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a lightweight substantially rigid torso board, substantially smaller in length and width than the mattress elements; (iii) at least one surface element on the torso board constructed and adapted to retain the torso board in a chosen - 6 - position in between two adjacent foam mattress elements; (iv) a separation means between each of the mattress elements, and between the mattress elements and the torso board, permitting each mattress element to move and to flex separately; and (v) a containment means adapted and constructed to ensure that the plurality of mattress elements together with the torso board remain in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements together with the core element to slight lateral compression. In a further more detailed aspect, this invention provides a foam mattress comprising a foam mattress element of suitable length, width, thickness, and hardness, together with two lengthwise modulator panels along each lengthwise edge of the mattress element, of medium hardness foam. Thus, in its broadest aspect, this invention provides a mattress comprising a plurality of foam mattress elements, which themselves provide a significant range of choices of firmness to the, or each, user. To this can be added a higher level of firmness, either over a partial area of the mattress by means of the torso board, or over substantially the whole area of the mattress by means of the rigid core element. If deemed desirable, both a torso board and a core element could be used together. Additionally, all of these choices are available to the, or each, user of the mattress. In the case of a double bed, if these choices are exercised in the manner set forth - 7 - below, a substantially constant top sheet height is maintained. Thus, although the two halves of a double bed may have remarkably different properties, the bed coverings present a flat top surface. Alternatively, the preferred form of foam mattress element, used in the mattress sets, itself, when used alone as a mattress, presents improved properties over the commonly used simple foam slab mattress. Preferably, the plurality of foam mattress elements comprises a set of foam mattress elements, several of which have a different degree of firmness. Preferably, at least one foam mattress element includes at least one lengthwise modulator panel, of medium hardness foam. Preferably, in a mattress or mattress element including modulator panels, the panels have a wedge-shaped cross-section, and are attached to a corresponding bevelled edge of the mattress or mattress element. Preferably, the rigid core element has a layer of foam on its upper surface and a layer of foam on its lower surface, and most preferably, the upper and lower layers of foam are of different firmness. Preferably, the mattress elements comprising a single bed include one rigid core element, or one torso board, or both. Preferably, the mattress elements comprising a double bed include two sets of foam mattress elements, each about half the width of the bed; with which may be combined - 8 - one or two rigid core elements each about half the width of the bed, and if desired, one or two torso boards. Preferably, a torso board is used alone, or separately for the, or each, user of the mattress. Additionally, a torso board may be used in combination with a rigid core element, preferably placed above the core element and separated from it by at least one mattress element. Preferably, the separation means comprises at least one layer of fabric associated with at least one face, of two contacting faces, of the mattress elements, a core element, and a torso board, if present. Preferably, the containment means comprises a fitted sheet means, which may further include both an additional lower surface, and openable closure means to enable laundering. Preferably, the containment means includes a cradle means adapted to retain, and to ensure constant lateral pressure upon the mattress elements. In a further preferred alternative combination, both a fitted sheet and a cradle are used as the containment. If a cradle is used, a flat sheet tucked-in can also be used, rather than a fitted one. Thus, for a double bed, the containment means can comprise one fitted sheet means which contains the two sets of mattress elements. In a further option, the containment means can comprise in combination a first and a second fitted sheet means each containing one set of mattress elements together with a third fitted sheet means containing the two sets of mattress elements encased in the first and the second fitted sheet means. For each of these - 9 - options, the assembled mattress can also be contained in a cradle means. The invention will now be described by way of reference to the attached Figures, in which: Figure 1 shows a single mattress, partly sectioned; Figure 2 shows a double mattress and a cradle; Figure 3 shows a detail of the cradle; Figure 4 shows a mattress set for a double bed; Figures 5, 6, 7, 8, 9, and 10 show details of mattress element construction; Figures 11, 12, 13, and 14 show details of core element construction; Figures 15, 16, and 17 show details of a second cradle construction to those shown in Figures 2, 3, and 4. Figures 18 and 19 show details of a third cradle construction to those shown in Figures 2, 3 and ; and Figure 20 shows a mattress including a torso board. In Figure 1 is shown perhaps the simplest form of construction for a mattress according to this invention. The mattress shown generally as 1 consists of five mattress elements 2, 3, 4, 5, and 6, which are sized to be a snug fit into the containment means 8 which ensures some constant lateral pressure on all the mattress elements. The elements can be rearranged in order to alter the hardness of the sleeping surface, since at least one of them, for example 4, has a different hardness to the others. This aspect of this invention will be discussed further, below. In Figure 1, the containment 8 is a fitted sheet but, as discussed in detail later, other methods may also be used. In practice, the overall thickness of the - 10 - group of foam mattress elements is chosen so that the overall vertical thickness, as at x in Figure 1, is substantially the same as that of a conventional mattress. Hence, the containment means 8 comprising a fitted sheet can be a conventional, readily available, ordinary fitted shee . Two further optional features of this invention are shown in Figure 1. At the bottom of the set, there is present a rigid core element 7, the construction of which is discussed below. As shown, it is at the bottom, but it can be placed anywhere in the set, including at the top, if a very hard surface is needed. At the top of the stack, within the fitted sheet 8, there is shown (partly cut away for clarity) a mattress pad 9. Generally this pad - which is commonly used on top of a conventional mattress - is a layer of cotton (or synthetic) wool batt, about 1 cm. thick, and is contained in a fabric cover. The mattress cover, if used, both adds to the overall comfort of the bed, and serves to protect the mattress elements from soiling. Commercially available mattress covers are commonly attached in much the same way as a fitted sheet, as at 9A and 9B. As shown in Figure 1, the fitted sheet includes a bottom retaining portion 10. The mattress pad 9, when it incorporates the retaining parts 9A and 9B, will also include a bottom portion 9C. This provides some choice as to which of these will provide the containment means. If it is chosen to make use of the mattress pad assembly as the containment, then the sides 9A, 9B and bottom 9C are so sized as to place the mattress elements under the required slight lateral compression. In that case, it is convenient to have the bottom portion 9C extend over the full area of the mattress; it is also then necessary to provide a closure, such as a zipper, so that the containment can be - 11 - opened in order to change the sequence in the stack. The sheet 8 can then be an ordinary commercial fitted sheet, or it may even be a flat sheet tucked-in, although a fitted sheet is preferred. Alternatively, the mattress pad need not provide the containment, which can be provided by the sheet alone, in which case the sheet bottom portion 10 preferably extends over the full area of the mattress, and a closure, such as a zipper, is needed. In a third option, both the sheet 10 and mattress pad assembly 9, 9A, 9B, and 9C can contribute to the containment means. A further feature of Figure 1 should also be noted. It can be seen that the mattress elements 2, 3, 4, 5, and 6 are not all the same thickness. Hence, the overall firmness in such an arrangement is a function of both the firmness of the foam used in each separate mattress element, and the thickness of each element. A thick, firm element will have more effect than a thin one. For a single bed, variation in mattress element thickness presents no difficulties, since regardless of the sequence, the set is always the same height. However, for a double bed, problems might arise if the bed uses two sets of mattress elements. Interchanging elements between the sets could result in the two sets having different overall heights, which is inconvenient. It is therefore preferred, at least for a double bed, that all of the foam mattress elements be of essentially the same thickness. The construction of each of the mattress elements is discussed in more detail below. In Figure 2 , a more complex arrangement is shown representing a double bed mattress. The mattress shown generally at 11 comprises two sets of mattress elements 12, - 12 - STIT TES EET 13, 14, 15, 16, and 22, 23, 24, 25, and 26, and two rigid core elements 17 and 27. As shown, these are not in the same place. When both sets are assembled into the cradle 21 with the overall fitted sheet 8 (shown cut away for clarity) , the top surface of the sheet 8 is substantially flat. Figure 2 also shows some further details concerning various options in the separation means and the containment means. The purpose of the separation means is to allow each foam mattress element to compress and to flex under the load imposed by the user. If no separation is provided, it appears that foam-to-foam friction relatively rapidly degrades the foam elements, especially in the main load areas, which are usually substantially along the center of the mattress. To eliminate this friction and to ensure that the mattress elements are free to compress and to flex independently, the simple way is to encase each mattress element, the core element, and a torso board, as discussed below, in an individual fabric case, as at 20 for the element 12. A mattress pad as at 19 can be provided within such a case, or it can be incorporated into the case. If such a pad is used, it is preferred that it is included on both sides of the mattress, thus avoiding the mattress elements becoming one-sided. Alternatively, the separation means can comprise a sheet of fabric as at 29 glued or otherwise attached to at least one face of each mattress element, to the core element, and, if required, to a torso board. Again, to avoid the elements becoming one¬ sided, it is preferred to provide such a sheet on both faces of each mattress element, of the core element, and of the torso board. - 13 If such an attached sheet is used, it need not be the full size of the mattress, and an edge border as at 29A, can be left uncovered. It appears that leaving this edge area open to foam-to-foam friction is beneficial, particularly in a double bed having two mattress sets, as it helps in eliminating any separation between the two sets along the mattress centerline. Further, it is also possible to include a mattress pad, as at 19, either with and as part of the sheet 29, or in conjunction with it, so that the pad is somewhat smaller than the mattress element with which it is associated. In that case, it has been found beneficial to provide a shallow recess in the mattress element to receive the pad, so that the mattress element retains an essentially flat surface. For such a double bed, it is also possible to use one, or more, mattress elements which are the full size of the bed. There are several choices for the containment for a double bed, which are much the same as those discussed above for Figure 1. If a cradle is used, as is discussed below, then the overall sheet 8 may be omitted, and each mattress contained in its own sheet, as at 33 on the element 12. It is also possible to include a mattress pad into the separation means, especially when this is an attached sheet, such as 29 in Figure 2. The containment means, in addition to the overall fitted sheet 8, and the pad 9, may include a cradle. One possible cradle arrangement, 21, shown in Figures 2, 3, and 4, comprises a base 18, and corner elements 28. These corners include a flex niche 28A allowing the corner to deflect, for example, when sat upon, as can be seen from - 14 - SUBSTITUTESHEET Figure 3. The corners 28 are so spaced that when all of the mattress elements are stacked into the cradle, the two sets will be under some slight lateral compression, in addition to any provided by a fitted sheet, such as 8. As a consequence of the lateral compression, the corner elements also serve to substantially eliminate centerline separation. If a cradle is used, as is preferred for a double bed, then although a sheet will be needed usually, it does not have to be a fitted one forming part of the containment. The manner of construction of the cradle depends upon the nature of the base to be used underneath it. If it is to be used on top of an existing box spring base to replace an existing mattress, then the base 18 of the cradle can be relatively light material, for example the 3mm. thick hardboard known as masonite, and perhaps need not be continuous covering the whole area of the bed. It is also advantageous to provide some anchoring of the cradle 18 to a box spring base. Conveniently, this can be done by the use of cooperating velcro patches, as at 18A in Figure 3. Alternatively, if the cradle is to be placed on a base, which provides adequate support only at the edges together with one or two cross-beams, such as a steel bed frame, then a much heavier material for the base 18 will be needed. For example, for a single bed it could be a sheet of 20mm. plywood of suitable size. As shown, the double bed of Figure 2 uses two sets of mattress elements. This is not necessary, as a perfectly useable bed can be made in the same way as in Figure 1, by using adequately sized elements. However, in such an arrangement, individual choice for each user is lost. Alternatively, a mix of full width and half width mattress elements could be used, but again, the level of personal choice is diminished, as shown in Figure . In - 15 - Figure 4 an end view is shown much the same as Figure 3, from which the containment, such as 8 in Figure 2, is omitted for clarity. The double bed mattress can be seen to be assembled from three sets of mattress elements, as follows: (i) a first group of one person wide elements 14, 15, 16 and 17, in which the core element 17 is roughly midway; (ii) a second group of one person wide elements 23, 24, 26 and 27, in which the core element 27 is near the bottom; and (iii) two full width elements 44 and 45, one at the top and the other lower down. Thus, the firmness of each of the user surfaces will depend to a degree on the firmnesses of the elements 44, 45 and the order in which both they and the remaining elements are assembled. In Figures 5, 6, 7, and 8 various methods of construction for each of the foam mattress elements are shown. It is in the various available choices for each of the foam mattresses making up a set that the flexibility to choose and to vary the firmness of the overall assemblage is to be found. Each mattress can differ as to its overall firmness, the inclusion of modulator side panels, and head and foot comfort panels. An interesting feature in this invention is that a mattress element including modulator panels is useful of itself, either as an additional overlay upon a conventional mattress, or if thick enough as a foam mattress. In foam mattress construction, the inherent "firmness" of the foam material used is important. - 16 - Unfortunately, commercial foam makers do not have a uniform standard used in describing this attribute of a given foam. The following information is given as a guide to the various levels of firmness used. Table 1 Foam Characteristic (1) Compression (2) VS Very Soft 1.82 S Soft 2.27 Medium 22.7 H Hard 27.3 (1) VS, S, and M are open cell foams; H may be open or closed cell foam. (2) The compression is measured by determining the weight, in kg, required to compress a 305mm square piece of foam from a thickness of 102mm down to 76mm; hence, a hard, stiff, foam has a high compression, and a soft foam, a low compression. Whilst often quoted, foam density is not overly important, as it is not directly related to foam firmness. Generally, foams with a density of greater than 32 kg/cubic metre are used. Density is more an indication of foam quality and longevity, as low density foams are generally structurally weaker materials. These tend to fail under repeated compression. A higher density foam is generally more resilient to impact, is structurally stronger, and retains its properties better. In the drawings of Figures 5 through 9 both the casing, shown as 20 in Figure 2, and any mattress pads, such as 19 or 29 in Figure 2, are omitted for clarity. In - 17 - use, each foam mattress element is provided with a separation means, as described above. The simplest form of foam mattress element, which is suitable for a single bed but has certain disadvantages in a double bed, is shown in Figure 5 and comprises a simple foam slab 30 of the correct length, width, and thickness. For all of the mattress elements (single or double) the length and width are chosen to fit the bed in question. The thickness is a separate variable. We prefer that there are at least three, preferably five, possibly six, and perhaps even seven, separate mattress elements. Thus, the five mattress elements, plus the core element, preferably will have a total thickness that fits a standard commercial sheet, and is equivalent to a normal mattress. In North America, as this thickness is commonly 15 to 20cms., each foam mattress is thus of the order of 3cms. thick. As is discussed above, it is preferred that all of the foam mattress elements should be of the same thickness, at least for a double bed. In Figures 6 through 10 more complex constructions are shown. Figure 6 shows an element including a single modulator side panel 31 on one side of the main part 30 of the mattress, and Figure 7 shows two such modulator panels 31 and 32. As can be seen from Figure 9 which shows the top face of the mattress of Figure 7, the modulator panels 31 and 32 extend for the full length of the mattress. The part section in Figure 10, on the line A in Figure 9, shows that these panels are tapered inwardly toward the center of the mattress, and the outer edge of the main part of the mattress has a corresponding bevelled face. The modulator panels are usually, made from a medium foam. They serve in a single bed to provide an area - 18 - of edge stiffness. In a double bed, the modulator panels, in addition to providing an area of edge stiffness, serve several other functions, most of which are as a result of the wedge-shaped cross section used (see Figure 10) . They help to minimize variation vertically in two sets of mattress elements in a side-by-side relationship under compression due to body weight. They help to provide a smooth transition from the central area of each mattress element to_the edge areas, thus avoiding an abrupt change. They help minimize sheet height variation on the center line, for example when two users are of significantly different weights. This last is impossible with a conventional mattress. As the modulator panels are usually made of medium foam, they are often not used with a medium foam mattress element, as in Figure 5. If only one modulator is present, as in Figure 6, this would be used in a double bed, with the modulator panel at the center of the bed. Generally it is more convenient to include two modulator side panels 31 and 32. Figure 8 shows a more complex five part mat mainly useful as the top mattress element in the set. The center panel 38 is chosen to be the desired hardness. The two side panels, 34, 35, which can also be tapered as in Figure 10, serve as modulator panels. In this case, the side panels 34, 35 generally are wider than the modulator panels. The two insert panels 36 and 37 are head and foot comfort panels. For example, 33 will be a relatively hard foam, 34 and 35 both medium foam, and 36 and 37 a soft foam, but other combinations are contemplated. When used as a mattress on its own, and not as part of a set, the construction of Figures 7 and 8 offers - 19 - significant advantages over a simple foam slab, as is commonly used. Figures 11, 12, 13 and 14 show the construction of the rigid core element, such as 17 and 27 in Figure 2. The core element is shown in part cut away plan in Figure 11, as an exploded diagram in Figure 12, and sectioned along the line B in Figure 13. An alternative partial section corresponding to the section in Figure 13 is shown in Figure 14. The core element comprises a top first cushion layer of foam 39, edge foam panels 40, a central stiff core 41, and a second cushion layer of foam 42. The central stiff core is suitably lightweight compressed board, such as 3mm. hardboard (Masonite) . Alternatively a suitably stiff plastics board, such as ABS, could be used. The edge foam panels 40 serve as a cushion to soften the edge of the element, and also in the same way as the modulator panels described above. The two foam cushion layers 39 and 42 provide a level of softness in use. Preferably, in these layers the upper layer is of a medium foam, and the lower layer is a relatively soft foam, and, as shown in Figure 13, one may be thicker than the other, thus providing two different levels of cushioning. Preferably, the core element is also encased in its own suitable fabric casing, 43. In Figure 13 the edge foam panels 40 are shown as being of substantially rectangular cross-section. It is also convenient, as is shown in Figure 14, to construct these as at 46 with a similar tapered shape, as is used for the modulator panels. In that case, the.side edges of the cushion layers 39, 42 are also bevelled to accommodate the taper in the edge panels. In Figures 15, 16 and 17 is shown an alternative form of cradle for either a single bed, as in Figure 15, or a double bed, as in Figure 16. Details of the corner construction are shown in Figure 17. In these Figures, - 20 - details of the mattress element construction are omitted for clarity. Further, the support options in Figures 15 and 16 can be interchanged. Referring to Figure 15 first, a mattress shown generally at 50 is supported on an existing conventional box spring, 51. The cradle comprises four corner elements 52, and four linking strap elements 53. The corners, 52, are attached to the box spring 51 by cooperating velcro patches, as at 54. Figure 16 shows a similar arrangement for a double bed with two mattress element sets, 50A and 50B. Four corner elements 52 are connected by four linking strap elements 53, ' and are attached to the base by the cooperating velcro units 54. Other fixing means, such as a strap, could also be used. Two options for supporting the mattress are shown; in practice, only one would be used, for the full width of the bed. On the left, as at 55, a one piece relatively thick cradle base is used, such as a sheet of plywood. On the right, as at 56, a sectioned cradle base comprising a plurality of support beams is used. Either of these bases could be used supported by a suitable bed frame. Figure 16 shows the corner in more detail. The main body 52 of the corner is made of a stiff, or stiffened, fabric, for example two layers of a decorative fabric with a layer of stiffening bonded therebetween. The bottom angle is strengthened with a plastic insert 58: this face rests on the underlying cradle support. Each vertical part of the corner includes a plurality of horizontal, 59, and vertical, 60, 61, flexible stays. Gaps are provided between these stays so that the corner is flexible, and will bend, for example if the user sits down on the corner of the mattress. The linking strap elements - 21 - 53 are releasably joined to the corners 52 by fasteners, as at 62, such as a snap. The corners and the lining strap elements are so sized that when the mattress elements are inserted they are placed under slight lateral compression. In order to change the sequence in a mattress set, either the set is removed and replaced, or one of the linking straps is detached, in order to free the set. In Figures 18 and 20 a third form of cradle is shown; Figure 18 is a double bed, and Figure 20 is a single bed. The arrangement of the mattress elements within the cradle is shown in Figure 19, which is a part section on line C-C in Figure 18. Referring first to Figure 18, the cradle shown generally at 63 is supported on a support shown schematically at 64. The same considerations apply to the support 64 as have been discussed earlier. The cradle comprises a base, 65, with an upstanding core 66 around its four edges. Again, the nature of the base chosen will be in large part determined by the nature of the support 6 . The outer face of the core is covered with a layer of upholstery foam 67, and then cased in suitable upholstery material 68. A filler layer, 69, may be included as well. The top edge of the foam 67 extends inwardly up above the core 66, on all four sides, to provide an inward facing upholstered upper horizontal lip element 70. On the inner face of the core similarly constructed lower vertical lip elements are provided, as at 71. As can be seen from Figure 19, the lower lip elements project inwardly the same distance as the upper one. These lip assemblies serve three interrelated purposes. First, they provide an upholstered rim all around the bed. Second, they serve to hold the foam mattress elements in place, and to provide the small amount of lateral compression needed, as the space inside them is a little smaller than the foam mattress elements. - 22 - Third, by being flexible, and by having free spaces as at 72 in between them, space is provided for tucking in bedclothes, such as sheets and blankets. A cradle of this type can be made as one piece, as shown in Figure 20 for a single bed, or in two pieces if desired as shown in Figure 18 for a double bed. A further problem that can arise for the user of a bed is that it is desirable, on either a short term basis as the result of injury, for example, or on a long term basis, to be able to make one area of a sleeping surface significantly stiffer than the remainder. With a normal mattress this is not easily achieved in any way that is comfortable. As is shown in Figure 20 this is easily achieved with a mattress according to this invention. Although illustrated in Figure 20 for a single bed, the same procedure can be used in a double bed, when assembled according to either of Figures 2 or 4. Suitable locations are indicated at Y in Figure 2, and Z in Figure 4. In Figure 20 is shown a single bed using the same form of cradle as is shown in Figure 18. Inserted into the cradle shown generally at 73 is a set of mattress elements 74, 75, 76, 77, 78, and 79. These mattress elements are all constructed as discussed above, and generally will be of differing firmness and will include a core element. Included in the set of elements is a torso board, 80. As shown it is between elements 75 and 76. If placed higher, as at Y in Figure 2, a greater degree of firmness is obtained. If placed lower, as at Z in Figure 4, a lesser degree of firmness is obtained. As shown in Figure 20, the torso board, unlike the core element, is significantly smaller than the remainder of the elements making up the mattress, and consequently it will provide increased firmness over only a limited area of the mattress. Also as - 23 - a consequence of the smaller size, it can be located wherever it is needed. Thus unlike the core element the torso board can provide a harder area to support the spine, and yet still leave the remainder of the sleeping area acceptably soft. The torso board is fabricated from thin light weight material, and generally is not padded like the core element. It is necessary to ensure that the torso board will remain where it is placed whilst the bed is in use. Hence it is desirable to have at least one relatively non- skid surface. How this is achieved depends on the material used for the torso board. If it is fabricated from a thin stiff fibre board, such as masonite or hardboard, a fabric casing (much the same as those used on the foam mattress elements as described earlier) is convenient. If it is fabricated from a plastic sheet, such as ABS, then no fabric casing appears to be needed. As the torso board is relatively thin, of the order of 5-10mm, it can be added to an existing mattress without materially affecting the overall thickness. Generally a torso board will be up to about 1.7 m in length, and up to about 1.0 m in width. It is also contemplated that both a torso board and a rigid core element can be used together. Obviously, the core element would not be placed above the torso board, and likely would not be immediately below it. Thus in Figure 20 one of the mattress elements 77, 78, or 79 could comprise a core element. Exactly how the mattress is assembled depends on the desired level of firmness. For a very hard support surface, the core element, such as 17, 27 in Figure 2, is located on top of the mattress elements within the containment means. To get a softer surface, the core element is moved downward in the stack and one or more - 24 - mattress elements are placed above it. This allows for a constant sleeping surface height, even in a double bed, with varying levels of firmness between the two sides. If six mattress elements are available, which may include a rigid core element, each of which is of a different firmness, then there are up to 720 possible combinations for the mattress. It should also be noted that where a plurality of mattress elements are used, the firmness can be varied simply by changing the sequence in which the mattress elements are stacked in the mattress containment means above any base, such as 18 in Figure 2. The foam mattress as disclosed herein, and comprising at least a plurality of foam mattress elements, is meant to act as a substitute or a replacement for a conventional mattress. In this sense, it requires a flat substantially rigid base on which to rest. In the absence of a flat substantially rigid surface, the mattress herein described would require at least one bed board to act as the support surface. Thus, the mattress herein described could rest on a conventional box spring or on a frame with at least one bed board thereon. If it is to be used on a frame, then it is convenient to use a construction including a cradle, such as is shown in Figures 2, 15, 19, and 20. In that case, the base of the cradle rather than being a relatively light stiff board material, such as masonite, advantageously is constructed to provide a substantially rigid support surface for the mattress elements. A cradle can also be constructed on a box unit, suitably upholstered on its sides, to replace the box spring unit commonly used beneath a conventional mattress. It is thus apparent that the construction of the base part of the cradle is adapted to suit the properties of the surface onto which the mattress unit and cradle will be laid when in use. - 25 - SUBSTITUTESHEET As is discussed at some length above, it is very desirable to provide a containment means for a mattress according to this invention. The containment means can be chosen in several ways, in part by the mattress user and in part by the mattress maker. One option is to use a conventional commercial fitted sheet, upon which the user lies, and which is removed for laundering. Such a fitted sheet generally encases both the top, the sides, and a proportion of the underside of the mattress, and is elasticized at the edge in the head and foot areas to keep it in place. It is thus under some overall tension when installed on to a mattress, and therefor exerts a level of lateral compression on the mattress elements. Alternatively it is convenient to use a mattress pad assembly, either as the containment or in conjunction with a fitted sheet. Commercially available mattress pads are constructed in the same way as a fitted sheet and thus will provide the required lateral pressure on the mattress elements. This method has the advantages that the pad will hold the stack as a coherent assembly whilst the bed sheet is being changed. In the preceding discussion the mattress elements, and the core element, are referred to as being made from, or incorporate, "foam" . This term is well understood in the upholstery art. It is used to refer to foam rubber, but latterly refers to foam materials made from synthetic polymers, including synthetic rubbers and other polymers. In modern practice, polyurethane materials are commonly used. These can be either open cell or closed cell materials. Further, it is also known to control the firmness of a foam material by including deliberate voids within it, and to contour its surface. The voids commonly are deliberately shaped holes, such as cylindrical ones. The use of such procedures is within the concepts of this invention. - 26 -

Claims: THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS: 1. A mattress comprising in combination an assembly of mattress components chosen from the group consisting of: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a plurality of first separation means, at least one of which is associated with each of the foam mattress elements, permitting each mattress element to compress and to flex separately; (iii) at least one lightweight substantially rigid core element of substantially the same length and width as at least one of the plurality of foam mattress elements; (iv) at least one second separation means between the rigid core element and the foam mattress elements permitting the foam mattress elements adjacent the core element to compress and to flex separately; (v) a lightweight substantially stiff torso board, substantially smaller in width and length than at least one of the plurality of foam mattress elements; (vi) at least one surface element on the torso board constructed and adapted to retain the torso board in a chosen position in between two adjacent foam mattress elements, and (vii) a containment means adapted and constructed to ensure that the - 27 - plurality of foam mattress elements remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements to slight lateral compression; provided that the mattress assembly includes at least components (i) and (ii) . 2. A mattress according to Claim 1 which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a separation means between each of the mattress elements permitting each mattress element to compress and to flex separately; and (iii) a containment means adapted and constructed to ensure that the plurality of mattress elements remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements to slight lateral compression. 3. A mattress according to Claim 1 which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a lightweight substantially rigid core element of substantially the same length and width as the foam mattress elements; (iii) a separation means between each of the mattress elements, and between the - 28 - mattress elements and the rigid core element, permitting each mattress element to compress and to flex separately; and (iv) a containment means adapted and constructed to ensure that the plurality of mattress elements together with the core element remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements together with the core element to slight lateral compression. . A mattress according to Claim 1 which comprises in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a lightweight substantially rigid torso board, substantially smaller in length and width than the mattress elements; (iii) at least one surface element on the torso board constructed and adapted to retain the torso board in a chosen position in between two adjacent foam mattress elements; (iv) a separation means between each of the mattress elements, and between the mattress elements and the torso board, permitting each mattress element to move and to flex separately; and (v) a containment means adapted and constructed to ensure that the plurality of mattress elements together with the torso board remain in their - 29 - chosen order in a substantially vertical stack, and to subject the plurality of mattress elements together with the core element to slight lateral compression. 5. A mattress according to Claim 1 comprising in combination: (i) a plurality of foam mattress elements, at least one of which has a different hardness to the others; (ii) a plurality of first separation means, at least one of which is associated with each of the foam mattress elements, permitting each mattress element to compress and to flex separately; (iii) at least one lightweight substantially rigid core element of substantially the same length and width as at least one of the plurality of foam mattress elements; (iv) at least one second separation means between the rigid core element and the foam mattress elements permitting the foam mattress elements adjacent the core element to compress and to flex separately; (v) a lightweight substantially stiff torso board, substantially smaller in width and length than at least one of the plurality of foam mattress elements; (vi) at least one surface element on the torso board constructed and adapted to retain the torso board in a chosen 30 - position in between two adjacent foam mattress elements, and (vii) a containment means adapted and constructed to ensure that the plurality of foam mattress elements remain situated in their chosen order in a substantially vertical stack, and to subject the plurality of mattress elements to slight lateral compression. 6. A mattress according to Claim 1 wherein the plurality of foam mattress elements comprises a set of elements, several of which have a different degree of firmness. 7. A mattress according to Claim 1 wherein at least one mattress element further includes at least one lengthwise edge modulator panel, of medium hardness foam. 8. A mattress according to Claim 1 wherein at least one mattress element further includes two lengthwise edge modulator panels, of medium hardness foam. 9. A mattress according to Claim 7 wherein the modulator panel is of a wedge-shaped cross-section, and the foam mattress element has a corresponding bevelled edge. 10. A mattress according to Claim 1 including a set of foam mattress elements each of which are of the same length and width. 11. A mattress according to Claim 1 including a set of foam mattresses, in which set each are the same length, and at least one is substantially twice the width of the others. - 31 12. A mattress according to Claim 1 wherein the foam mattress elements are all of substantially the same thickness. 13. A mattress according to Claim 1 wherein the foam mattress elements are not all of substantially the same thickness. 14. A mattress according to Claim 3 wherein the foam mattress elements and the rigid core element are of substantially the same length and width. 15. A mattress according to Claim 1 including two sets of foam mattress elements, each of which are of the same length and width, and wherein the lateral pressure provided by the containment means is sufficient to urge the mattress elements together at the mattress center line. 16. A mattress according to Claim 15 further including two core elements, each of substantially the same length and width as the foam mattress elements. 17. A mattress according to Claim 1 including a set of foam mattress elements, in which set each are the same length and thickness, and at least one is twice the width of the others, and wherein the lateral pressure provided by the containment means is sufficient to urge the mattress elements together at the mattress center line. 18. A mattress according to Claim 1 including a core element and a set of foam mattress elements, in which set each are the same length and thickness, and at least one is twice the width of the others, and is of the same length and width as the core element, and wherein the lateral pressure provided by the containment means is sufficient to urge the elements together at the mattress center line. - 32 - 19. A mattress according to Claim 1 including two core elements and a set of foam mattress elements, in which set each of the foam mattress elements are of the same length and thickness, and at least one is twice the width of both the other foam mattress elements and each core element, and wherein the lateral pressure provided by the containment means is sufficient to urge the elements together at the mattress center line. 20. A mattress according to Claim 1 wherein the first separation means comprises a sheet of fabric attached to one side of each mattress element. 21. A mattress according to Claim 1 wherein the first separation means comprises a sheet of fabric attached to both sides of each mattress element. 22. A mattress according to Claim 1 wherein the first separation means comprises a fabric casing around each mattress element. 23. A mattress according to Claim 1 wherein the first separation means comprises a fabric casing around each mattress element, and a fabric casing around the core element. 24. A mattress according to Claim 1 wherein the containment means comprises at least one fitted sheet means. 25. A mattress according to Claim 15 wherein the containment means comprises a first and a second fitted sheet means each containing a set of mattress elements, together with a third fitted sheet means constructed and arranged to contain both sets of mattress elements contained in the first and second sheet means. - 33 - 26. A mattress according to Claim 1 wherein the containment means comprises a cradle means. 27. A mattress according to Claim 2 wherein at least one mattress element comprises a center panel, two side panels the same length as the mattress element each side of the center panel, and head and foot comfort panels. 28. A mattress according to Claim 27 wherein the two side panels comprise two edge modulator panels of medium hardness foam. 29. A mattress according to Claim 1 further including at least one mattress pad. 30. A mattress according to Claim 1 wherein the rigid core element comprises in combination a first cushion layer of foam; four edge foam panels; a central stiff core; and a second cushion layer of foam. 31. A mattress according to Claim 30 wherein the stiff core is a lightweight compressed board. 32. A mattress element according to Claim 1 wherein the second separation means comprises a fabric casing which contains the rigid core element. 33. A mattress according to Claim 30 wherein in the rigid core element the two lengthwise edge foam panels comprise lengthwise edge modulator panels of medium hardness foam. 34. A mattress according to Claim 20 wherein the sheet of fabric is of the same length and width as the mattress element to which it is attached. - 34 - 35. A mattress according to Claim 1 wherein the second separation means comprises a sheet of fabric attached to one side of the core element. 36. A mattress according to Claim 1 wherein the second separation means comprises a sheet of fabric attached to both sides of the core element. 37. A mattress according to Claim 35 wherein the sheet of fabric is of the same length and width as the core element to which it is attached. 38. A mattress according to Claim 20 wherein the sheet of fabric is of lesser length and width than the mattress element to which it is attached. 39. A mattress according to Claim 1 wherein the containment means comprises at least one fitted mattress pad assembly. 40. A mattress according to Claim 24 wherein the containment means comprises at least one fitted sheet means and at least one fitted mattress pad assembly. 41. A mattress according to Claim 35 wherein the second separation means further includes a mattress pad. 42. A foam mattress comprising in combination a foam mattress element and at least one lengthwise edge modulator panel of medium hardness foam. 43. A mattress according to Claim 42 including two modulator panels. - 35 - 44. A mattress according to Claim 42 wherein the at least one modulator panel is of a wedge-shaped cross- section, and the foam mattress element has at least one corresponding bevelled edge. 45. A mattress according to Claim 42 wherein the foam mattress element comprises a center panel, and a head and a foot comfort panel. - 36 -

Inventors: SCHWARTZ JACK, SCHWARTZ, JACK
Applicants: SCHWARTZ JACK, SCHWARTZ, JACK
Application year: 1992
Main classification: A47C27
IPC codes: A47C27