This invention relates to bedding systems and, more particularly, to a bedding system for maximizing the comfort of a person reclining atop the system. Sleep studies and sleep research have increasingly confirmed that the quality of a person's sleep is dependent upon the comfort of that person when reclining atop a sleeping surface. Researchers have also determined that comfort is affected by the spinal alignment of a person reclining atop a mattress or the amount of pressure that is applied to the body surface of a person atop a mattress. Spinal alignment is generally defined, for purposes of such research studies, as that alignment which the spine of a person assumes when that person is standing in a relaxed position with the feet approximately 12 inches apart. This is the position of the spine which should ideally be maintained when that person is reclining atop a sleeping surface. When a healthy sleeper becomes "uncomfortable," either consciously or subconsciously, they may move to relieve the discomfort. During the

night, a healthy person passes through five levels of sleep, which are called stages I-IV and REM (Rapid Eye Movement) . Stages I and II are the lightest sleep, and stages III and IV are the deepest. The REM stage is that level in which we dream. All levels of sleep are important, but it is in stages III and IV that we get our deepest, most restful sleep. Postural shifts of the body during the night are a normal and healthy part of the sleeping cycle. When a sleeper moves, they must arouse to a lighter level of sleep (stage I or II) or awaken. Therefore, the more discomfort a sleeper feels during the night, the more they will move, which will require them to spend more time in lighter levels of sleep and less time in deeper, more restful sleep.

In Torbet U.S. Patent No. 4,662,012 and in co-pending U.S. Patent Application Serial No. 07/256,902 filed October 12, 1988 and assigned to the assignee of this application, there is disclosed an air mattress for supporting a person in a reclining position while maintaining spinal alignment of that person and while maintaining minimal supporting body surface pressure. To that end, the mattresses disclosed in both the above-identified patent and pending application utilize zones of differing air pressure along the length of the mattress. This is in contrast to a conventional non-zoned type of mattress which maintains a common degree of firmness or

resistance to vertical deflection over the whole surface area and for the full length of the mattress.

Experimentation has now shown that a mattress should be divided into four, and preferably five, longitudinal - zones of differing firmness or resistance to vertical deflection in order for the body of a person reclining atop the mattress to be maintained in spinal alignment when lying on either their back or side. Spinal alignment on an air bed of the type described in the above-identified pending patent application is ideally achieved when the mattress is divided into five longitudinal zones, each having a different level of resistance to vertical deflection. While the air mattress described in U.S.

Patent No. 4,662,012 is ideal for supporting a person reclining atop the mattress while minimizing supporting body surface pressure and while maintaining spinal alignment, spinal alignment can also be achieved by zoned mattresses of more conventional construction, as for example, foam or spring mattresses, so long as the mattresses are zoned or divided into longitudinal sections of differing resistance to vertical deflection. Such a zoned spring mattress is disclosed in Kraft U.S. Patent No. 4,679,266. But, a zoned foam or spring mattress, such as the zoned mattress of U.S. Patent No. 4,679,266, cannot, because of the nature of foam or springs,

simultaneously achieve spinal alignment and minimal supporting body surface pressure.

In the use of a zoned mattress for achieving spinal alignment of persons reclining atop the mattress, persons of greater body density sink further into the mattress than persons of lower body density. Body protrusions (such as shoulders) also need to be accommodated. In the practice of the invention described in the above-identified air mattress application, the air mattress was required to be approximately eight inches in vertical height over the whole of the surface of the mattress in order that the shoulder of a heavy body resting atop the mattress in a side lying position did not sink through the mattress to the underlying mattress supporting surface. In actuality, the parts of the body which sink furthest into the mattress are the shoulder and the hips of the person reclining atop the mattress.

One of the factors which contributes significantly to the cost of a mattress, be it a zoned mattress of the type described hereinabove or a conventional unzoned mattress of fixed resistance to vertical deflection throughout the length and width of the mattress, is the cost of materials employed in establishing the vertical height of the mattress in order to prevent the mattress from bottomming out when a person is supported atop the mattress. From a cost standpoint alone, an ideal mattress would be one which

is substantially less thick than conventional mattresses utilized today, but which has sufficient resiliency over the length of the body to support the body in spinal alignment at lowest possible surface body pressure and which will not allow the body to bottom out. From a functional standpoint, such a mattress would be comfortable because of its maintenance of minimal body supporting surface pressures and maintenance of spinal alignment of a person supported atop the mattress.

In order to support a person reclining atop a mattress with a minimum supporting surface pressure, the person reclining atop the mattress must be lying horizontally and must be supported over the largest possible body surface area. In order to maximize the supporting surface area, the body of the person will necessarily be deep into the supporting mattress, and that mattress will conform absolutely to the body shape. The mattress, of course, will not have bottommed out at any location. The body will have both a varying density and a contour to which the supporting mattress will be applied. Thus, if the body is to rest in spinal alignment when reclining atop the mattress, the supporting forces in the mattress under load from the body must vary along the length of the body to match the body density and shape. If the body is to rest in spinal alignment when reclining atop the mattress at the lowest

possible body surface pressure, the supporting pressures in the mattress must be as low as possible in order to permit the optimum or near optimum sinkage of the body into the mattress. Translated into design parameters for a mattress of spring or resilient foam construction, the mattress should ideally be of varying firmness along the length of the mattress, and that firmness should be as little as possible for lowest possible body surface pressure. As mentioned hereinabove, longitudinally zoned spring mattresses are capable of achieving spinal alignment of a person resting atop the mattress if the mattress is of sufficient depth to allow the shoulders and hips to sink into the mattress to a depth sufficient to maintain spinal alignment of that person. But, spring mattresses or bedding systems employing such mattresses are, as presently known, not capable of achieving spinal alignment while minimizing the supporting surface pressure on the body. The primary reason that this is not possible with compression spring mattresses is that the resistance to deflection of the springs increases as the springs are compressed and the height of compression springs in a mattress is limited. The taller the spring in the relaxed state, the greater is the deflection or compression of the spring before the force increases to balance the weight of a body lying on the spring. Thus, a body can sink further into a tall, weak spring

before the weight of the body is balanced than it can sink into a low, firm spring. If the spring is to be made sufficiently weak to enable a person to sink deeply into the mattress, then it must be tall in order to prevent the body of a person supported atop the mattress from bottomming out before the weight of the person is balanced by the resistance of the spring. In order to achieve or permit the greatest possible body penetration into the mattress, and hence, the lowest possible body supporting surface pressure, the springs of the mattress must be sufficiently tall, particularly in the shoulder and hip zones, to enable the body to penetrate deeply into the mattress so as to achieve spinal alignment of the person resting atop the mattress. But, very tall, weak compression springs in a mattress have intolerable lateral sway or instability, and this is especially true as the firmness of the springs is reduced. Thus, at the present time, mattresses are generally limited as a practical matter to compression springs no more than approximately six inches in height and mattresses which, with one-inch pads on each side of the mattress, are a total of approximately eight inches in height. With these limitations in mind, zoned spring mattresses, which have been capable of achieving spinal alignment of a person resting atop the mattress, have not been capable of achieving that spinal alignment with a

minimum body supporting surface pressure because they have not allowed a body to sink to a sufficient depth into the mattress to achieve that minimum supporting surface pressure. It has therefore been one objective of this invention to provide a bedding system which is capable with the use of spring-zoned mattresses of supporting of a body in spinal alignment either on their back or side while supporting that body with a minimal supporting surface pressure.

It has been another objective of this invention to provide an improved bedding system which utilizes a mattress of substantially less thickness or vertical dimension, but which, when employed in a complete bedding system, affords spinal alignment of a person reclining atop the mattress, whether on their side or on their back.

Still another objective of this invention has been to provide an improved bedding system which may be customized in order to provide spinal alignment of a particular size and body density of a person supported atop the mattress at a firmness of feel preferred by that person.

The invention of this application relies in part upon a well-known characteristic of compression springs, but one which has, to my knowledge, never heretofore been employed in a bedding system to achieve maximum comfort and spinal alignment. That

principle is the well-known one that the spring compression rate (the weight per distance of deflection) is substantially decreased if one compression spring is mounted atop another compression spring. As an example, if a load is placed on a five-inch high spring and deflects it three inches, the same load placed atop two tiers of the same spring (i.e., a five-inch spring placed on top of an identical five-inch spring) will cause the two-tiered spring to deflect six inches. Utilizing this principle, the invention of this application is capable of achieving spinal alignment in a mattress having springs to provide the resiliency of the bedding system while minimizing the body supporting surface pressure on a person reclining atop the mattress of the system.

Summary of the Invention

The invention of this application which accomplishes these objectives is a modular bedding system which comprises a rigid platform having depressions formed in the top surface thereof for the reception of resilient cushions, and a relatively thin mattress supported atop that platform and the cushions. In the preferred embodiment, there is a depression and one cushion located beneath the shoulders of a person reclining atop the mattress of the bedding system and a second cushion located

beneath the hips of a person reclining atop the system. In this preferred embodiment, the mattress is approximately four inches in thickness, and the cushions are each approximately four inches in thickness. The ^• mattress is preferably a longitudinally zoned firmness mattress, i.e., one having multiple zones of differing resistance to vertical deflection over the surface of the mattress, but it should be appreciated that some aspects of this invention lend themselves to the use of a single-zone mattress, i.e., one that is characterized by a common resistance to vertical deflection over the full top surface of the mattress.

The bedding system of this invention lends itself to customizing of a bed to provide spinal alignment at the preferred firmness of a person or customer utilizing such bedding system, including that firmness which provides the lowest possible body surface pressure. Differing persons have differing requirements for their bed. Some prefer a bed which has a very soft, cushiony feel, and others prefer a bed which has a much firmer feel. All, though, require that the bedding system maintain spinal alignment of their particular size, shape and weight bodies. Because personal preferences differ, there is a need for a bed which maintains spinal alignment of these differing bodies while still satisfying personal preferences for firmness of feel. The invention of

this application is particularly amenable to satisfying these requirements. To that end, it is envisioned that this invention will be modularized and sold from a selection of components to make a bedding system customized to a particular customer's personal dimensions and preferences. Specifically, it is envisioned that each customer will be weighed and measured and then mattresses and cushions matched to the dimensions and weight of that particular customer in order to provide a bedding system having the firmness feel desired by the customer while still maintaining spinal alignment of that customer when reclining or resting atop the resulting bed. Thus, a customer might select the particular firmness feel of mattress that he or she desires, including that firmness which provides the lowest possible body surface pressure, and then have that choice matched with his or her physical dimensions and weight in order to determine which of possibly five or more mattresses combined with cushion inserts is the ideal one for that customer. Because of different body densities, a mattress which might be firm for one person might be medium firm for another more dense, heavier person. That mattress would then be matched with a range of cushions in order to give rise to spinal alignment of that customer when supported upon the resulting bedding system. The customer might then select a particular headboard, footboard, bedside

cabinets and bed surround in order to complete the bedding system choice.

The determination of which of many mattresses and cushions would be chosen could be determined either from a chart, which would indicate for a particular size and density person which mattress would give rise to the requisite degree of firmness and the cushions which would be used in combination with that mattress for that particular person to provide for spinal alignment. Alternatively, a computer program could be used to make the same selection.

While it is envisioned that the invention of this application may be utilized with a zoned air mattress, such as the one described in the above-identified patent application, many of the advantages of this invention may be achieved by utilizing foam or spring mattresses having longitudinal zones of differing resistance to vertical deflection. Or, alternatively, the invention of this application may be used in combination with unzoned mattresses, i.e., mattresses which are of the same resistance to vertical deflection throughout the full length and width of the mattress and which may be combined with cushions of varying firmness. But, one of the principal advantages of the invention of this application is achieved when the mattress is a longitudinally zoned foam or spring mattress used in

combination with foam or spring cushions. In that event, the bedding system of this invention is capable of achieving spinal alignment of a person reclining atop the bedding system while minimizing body supporting surface pressures.

One very great advantage of the invention of this application is that it enables a bed to be selected from modular components which may be customized to meet a particular person's weight and dimensions so as to enable that person to sleep on the resulting bedding system with a selected degree of firmness comfort and in spinal alignment. This invention also has the advantage of giving rise to a modular bedding system which may be created from less expensive components than prior art bedding systems and which may be transported more easily and assembled by the user.

These and other objects and advantages of this invention will become more readily apparent from the following description of the drawings in which:

Figure 1 is an exploded perspective view of a bedding system embodying t^e invention of this application.

Figure 2 is a cross-sectional view through the bed of Figure l, when the components of that bed are assembled.

Figure 3 is a cross-sectional view taken on line 3-3 of Figure 2.

Figure 4 is a cross-sectional view similar to Figure 2, but illustrating the position assumed by the mattress and cushions when a person is resting on their side atop the mattress. Figure 5 -is a top plan view of the zoned mattress of Figure 1.

Figure 6 is a cross-sectional view similar to Figure 3, but of a double bed rather than a single bed. Figure 7 is a diagrammatic illustration of a bedding system embodying the invention of this application.

With reference first to Figure 1, there is illustrated a bedding system 10 embodying the invention of this application. This bedding system comprises a rigid bed platform 12, a pair of resilient cushions 14, 16 and a mattress 18. In the illustrated embodiment, the system also includes a supporting frame 20, as well as a headboard 22, footboard 24 and pair of sideboards 26.

The platform 12 is shaped as a rectangular parallelepiped or, as it is more commonly known, as a rectangular box. The top surface 28 of the platform is generally horizontal but has two longitudinally spaced depressions 30, 32 formed therein. Each of these depressions is also shaped as a rectangular parallelepiped. The depression 30 nearest the head end of the bed platform comprises a pair of vertical

walls 34, 36 and a bottom wall 38, each of which extends for the full width of the bed platform 12. Similarly, the second depression 32 is shaped as a rectangular parallelepiped. It has vertical walls 40, 42 and a bottom wall 44 which extend for the full width of the bed. In practice, the depressions 30, 32 extend downwardly from the top horizontal surface 28 of the bed platform 12 to a depth of approximately four inches. In addition to the horizontal top surface of the top wall 28, the bed platform 12 has a pair of sidewalls 46, 48 and a pair of end walls 50, 52. In practice, these walls may all be of minimal thickness if the bed platform is fabricated, or the platform may be solid between the sidewalls 46, 48 if the platform is made from a lightweight molded material. The bed platform 12 may be fabricated from sheet metal or pressed from sheet steel. Alternatively, it may be made of fiberboard or molded plastic. Irrespective of the material from which the platform 12 is manufac¬ tured, though, it is a rigid structure which is subject to minimal or no vertical deflection when a person or persons are reclining or sleeping atop the bedding system. The platform, though, is a substantially rigid structure having a top horizontal surface 28 divided into three longitudinally spaced sections: One section 28a at the head end of the platform, another section 28c at the foot end of the

platform, and a middle section 28b intermediate the two end sections 28a, 28c of the top horizontal surface 28.

The resilient cushion 14 resides within the depression 30 of -the bed platform 12, and the resilient cushion 16 resides within the depression 32. Each cushion is also shaped as a rectangular parallelepiped, and each cushion conforms to the shape of the depression within which it is located. In other words, each cushion is of the same width as the width of the bed platform 12 and is of approximately the same length as the depression within which it fits. Additionally, each cushion is of the same vertical height as the depression within which it fits so that when located within the depressions 30, 32, the top surfaces 54, 56 of the cushions 14 and 16 reside in the same horizontal plane as the top surface 44 of the bed platform 12.

In the preferred practice of this invention, the bed platform 12 is supported upon a supporting frame 20 which may be a conventional "Hollywood" style of bed frame made from right-angle channels and supported upon legs 60 having casters 62 at their lower end. The bedding system 10 is completed by the addition of a headboard 22, footboard 24 and sideboards 26 secured to the supporting frame 20.

The mattress 18 may preferably be a conventional mattress having springs or urethane foam

or any other conventional resilient structure contained internally of the mattress to provide resiliency and support. Alternatively, the mattress 18 may be an air mattress of the type described in co-pending U.S. -Patent Application Serial No. 07/256,902 filed October 12, 1988 and assigned to the assignee of this application, but modified to be of lesser vertical height. But, whether the resiliency of the mattress is provided by urethane foam or by springs or by pressurized air pockets, the mattress 18 is preferably a multiple-zone mattress of differing firmness over the surface area of the mattress. The multiple zones of the preferred mattress is divided into five longitudinal zones or sections I8a-18e by the mattress structure and by the cushions 14, 16 which underlie the mattress. These zones are a head section zone 18a located in one end of the mattress between that end of the mattress and the edge of the cushion 14, a shoulder section zone 18b overlying the cushion 14, a waist section zone 18 located between the cushions 14, 16, a hip section zone 18d overlying the cushion 16, and a foot section zone located between the cushion 16 and the end of the mattress. As explained more fully hereinafter, the purpose of these differing sections or zones is to enable a person to recline atop the mattress on either their side or back and have the mattress support the person in spinal alignment, i.e., in the position the spine

would normally assume when the person is standing in a relaxed position and, preferably, with a minimum body supporting surface pressure. These differing sections 18a-18e conform in plan view and overlie the surfaces 28a, 30, 28b, 32 and 28c, respectively, of the bed platform. As illustrated in Figure 5, the head section 18a of the mattress extends for approximately 2/15 of the length of the mattress, the shoulder section 18b of the mattress extends for approximately 3/15 of the length of the mattress, and the waist section 18c of the mattress extends for approximately 1/15 of the overall length. The hip section 18d of the mattress extends for approximately 4/15 of the length of the mattress, and the foot section extends for approximately 5/15 of the length of the mattress. Because of the differing resistance to vertical deflection imparted to the bedding system 10 by the resilient cushions underlying the mattress, the bedding system 10, when customized by specific firmness mattress and specific firmness cushions, ensures that a person reclining atop the mattress, as illustrated in Figure 4, does so while maintaining spinal alignment from their head to their foot because of the differing depths which the different parts of their body sink into the mattress or, in the case of this bed, into the mattress 18 and cushions 14, 16, respectively.

With reference now to Figure 4, it will be seen that a person reclining atop the bedding system 10 of this invention sinks further into the mattress in the shoulder and hip zones of the mattress than in any other portion, - even if those portions are of greater resistance to deflection than the head and leg support zones of the mattress. Obviously, persons of greater body density sink into the mattress and supporting cushions to a greater depth than lighter, lower-body density persons. Experimentation has established that a comfortable mattress which provides spinal alignment of a person reclining atop the mattress should be approximately eight inches in thickness in order to ensure that the heaviest body resting atop the mattress while reclining on their side does not bottom out on the mattress. That same overall deflection depth is available according to the practice of this invention, but the invention of this application enables a mattress to be made of much less thickness or depth D (Figure 1) . In the preferred practice of this invention, the mattress is only four inches in vertical depth, and the cushions 14 and 16 are similarly only four inches in depth. These dimensions could, of course, vary and could obviously be made greater than four inches, but four inches has been found to be particularly appropriate for the practice of one aspect of this invention.

The bedding system 10 of this invention lends itself to modularizing a customized bed. A customized bed, in accordance with the practice of this invention, is one in which the mattress 18 and cushions 14 and 16- are selected so as to match the weight and dimensions of a particular person and give that person a selection of firmness such that when that person is sleeping upon the customized bed, their body will be maintained in spinal alignment whether the person is sleeping on their side or back. In accordance with this aspect of this invention, a bedding system of this invention would be merchandized by a store which maintains an inventory of a plurality of mattresses of varying firmness and of varying lengths and widths, i.e., twin, regular, king and queen sizes. Whenever a person was to purchase a bedding system, that person would be weighed and measured and would choose a particular desired firmness feel for sleeping comfort, i.e., a mattress which was firm or soft or of medium firmness in feel. That customer's dimensions would then be utilized via a chart or a computer to select a mattress having that particular firmness feel, as well as a configuration which, when matched with selected cushions, would give rise to spinal alignment of that weight and dimension body when reclining atop the mattress. With the mattress and cushions selected and the bed platform being standard for any particular style of bed, i.e.,

twin, regular, queen or king, the person would then complete their bedding selection by choosing the bed surrounds to complete the bed, i.e., the footboard, headboard, sideboards and any other accessories associated with the bed.

It will now be appreciated that the invention of this application lends itself to modularized manufacture and sale of customized beds intended to provide for spinal alignment and reduce the costs of transport and assembly to each purchaser of a bed. Since comfort has been established to be in substantial part a function of the spinal alignment maintained while the person is sleeping in the bed, this modularized, customized bed will maximize the sleeping comfort of each bedding customer at a reduced cost.

As described hereinabove, the mattress 18 is either actually or effectively, as a result of the underlying surfaces, divided into five longitudinal zones 18a-18e (Figure 5) . These zones all differ in resistance to vertical deflection, either as a consequence of the internal structure of the mattress, or as a consequence of the resiliency or lack thereof, o the platform 12 and cushions 14 and 16. With reference now to Figure 7, there is illustrated in diagrammatic fashion a bedding system comprising a mattress 18 and cushions 14, 16 for obtaining spinal alignment of a person reclining atop

the mattress, while simultaneously maintaining the lowest possible body supporting surface pressure on the surface of the person reclining on the mattress. This mattress is divided into three zones, A, B, and C, with the middle zone B being of differing firmness (i.e., resistance to vertical deflection) than the end zones A and C. The end zone A occupies the head zone 18a and shoulder zone 18b of the mattress, the middle zone B occupies the waist zone 18c of the mattress, and the end zone C occupies the hip zone 18d and foot zone 18e of the mattress. The cushion D underlies the shoulder zone of the mattress, and the cushion E underlies the hip zone of the mattress. In this example, it is envisioned that the mattress zone A, as well as the mattress zone C, would be of a common firmness, i.e., resistant to vertical deflection, while the mattress zone B would be of a differing and substantially greater firmness or resistance to vertical deflection. It is envisioned that in this example, this firmness or resistance to vertical deflection would be imparted to the mattress by springs contained internally of the mattress with the springs in the waist zone B being substantially more firm than the springs in the end zones A and C, respectively. In this example, it is also envisioned that the cushions 14 and 16 occupying the zones D and E beneath the shoulder and hip zones, respectively, of the mattress would also be resilient and have the

resiliency imparted to the cushion by springs. In this example, it is envisioned that the cushion 14 occupying the zone D would be of the same firmness as the mattress in zones A and C and that the cushion 16 occupying the zone- E would be of a greater firmness than the zones A and C of the mattress, but less than the firmness of the zone B of the mattress. A bedding system, such as that illustrated in Figure 7, would then be characterized by a head zone 18a of a first firmness, a shoulder zone 18b of a second firmness or resistance to vertical deflection less than that of the head zone because of the underlying resiliency of the cushion 14, and a waist zone 18c of substantially greater resistance to vertical deflection than that of either the head zone 18a or shoulder zone 18b. Additionally, this bedding system would be characterized by a hip zone 18d of greater resistance to vertical deflection than that of either the head zone 18a or shoulder zone 18b, but less than that of the waist zone 18c. And, the foot zone 18e would be characterized by a firmness or resistance to vertical deflection equal to that of the head zone 18a.

A bedding system made in accordance with the differing resistances to vertical deflection described and illustrated in Figure 7 would, in many instances, be capable of supporting a person reclining atop the bedding system on either their back or side in spinal alignment and with a minimal body supporting surface

pressure because the person supported atop the mattress would sink into the mattress to a sufficient depth to maximize the area over which the body would be supported. Such a system would support many shapes and configurations -of bodies in spinal alignment and with this minimum supporting body surface pressure. However, some bodies, because of their unusual height, weight and shape, might require a greater number, i.e., five, zones of differing firmness in the mattress even when the mattress is utilized in conjunction with cushions of differing firmness underlying the shoulder and hip zones of the mattress. Other persons, such as very light persons, might be capable of being supported on a mattress of two zones, or even a single zone, of firmness in the mattress with only differing zones of cushion firmness to obtain spinal alignment and lowest possible body surface pressure of the person supported atop the mattress. This last condition might be particularly applicable to very light, small bodies.

It is important to note that bedding systems employing the invention of this application take advantage of the principle that springs or resilient supports stacked one atop the other have differing rates of deflection (i.e., weight per linear unit of deflection) than the same springs when placed side by side. As a consequence of this characteristic of springs or resilient bodies, the bedding system of

this invention can be made to support a person in spinal alignment atop the bedding system with minimal supporting body surface pressures imposed upon the body by the underlying bedding system and with a minimal height or thickness mattress, and particularly with a spring mattress which has heretofore not been capable of such support.

With reference to Figure 6, there is illustrated a second embodiment of the invention of this application. In this embodiment, the single bedding platform 12' supports two mattresses 18' and 18'' so as to make up a queen or king-sized bed. The bed platform 12' is divided longitudinally by a longitudinally extending vertical divider 100 which separates two transversely spaced cushions 14', 14" or 16', 16" in each of the depressions 30', 30", or 32', 32", respectively. In this bed, the bottom surface of the depressions 30', 30" and 32', 32" which receive each cushion is made concave, and the bottom surface of each cushion is convex from one side of the cushion to the center of the bed. This configuration of the bottom of the depressions and the bottom of the cushions facilitates a person sleeping or reclining atop the mattress being maintained more or less in the transverse center of their mattress.

In lieu of making the bed platform 12 in the shape of a rectangular parallelepiped with depressions formed therein, the bed platform 12 could as well be

made from a flat sheet of material, such as a flat sheet of plywood, upon which there are placed blocks shaped as rectangular parallelepipeds. If the bed platform were made in this way, the head section of the bed platform might be in the form of a block of relatively rigid foam, and similarly, the raised foot section and waist section of the bed platform 12 could be made from relatively rigid foam. In this event, the top surfaces of the relatively rigid foam blocks making up the head, waist and foot sections of the bed platform would all have a flat horizontal top surface located in the same top surface as the top surface of the resilient cushions 14', 14" and 16', 16'', respectively. While I have described only a relatively few embodiments of my invention, persons skilled in this art will appreciate changes and modifications which may be made without departing from the spirit of my invention. Therefore, I do not intend to be limited except by the scope of the following claims.

I claim: