fig1 of the drawings shows a mattress 21 according to the present invention . the mattress shape and materials allow for conformity to and support of the body in sublime , prone or side and in sitting positions . the mattress 21 is formed from a plurality , five being shown , of modules 1 , 2 , 3 , 4 , 5 constructed of foamed material . any suitable foamed material , such as polyurethane , of various densities may be used to construct the modules . although five modules are shown , it is to be understood that the exact number of modules is not critical to the invention . the top layer 1 of the mattress is constructed of a low resilient layer of latex or a combination of latex and synthetic low resilient high density foams . the best mode of the invention calls for use of material with a resilience in approximately the 16 to 22 pounds 25 % ild range and a density of 2 to 5 pounds per cubic foot . in the best mode of the present invention , the average thickness of the material comprising the top layer should be about 1 and 1 / 2 inches . above the 1 and 1 / 2 inch lower limit , the thickness of the top layer is dependent on economic constraints and the availability of materials . however , the material should not be so thick that it fails to conform to the uniform concave arc formed by the upper surface of the center core 2 and the head section 3 of the base 22 . upper surface of the top layer 1 is molded or otherwise prepared to provide a section 11 of uninterrupted continuous undulatory elevations and depressions 6 across the lateral dimension of the upper surface , and to provide a section 12 at the head end of the top layer and section 10 at the foot end of the top layer which are substantially flat . although undulations are not required by the present invention and undulations of any size may be used , undulations approximately 3 / 4 inches high allow for greater conformity to small human crenelations than in flat mattresses and assist air movement and insulation in the mattress 21 . when a body rolls on the mattress , the air in the channels is forced out one side and drawn in on the other , the venturi effect drawing away body moisture . it should be understood , that although sections 12 and 10 are shown in fig1 as being of substantially identical dimension along the longitudinal axis of the mattress , such is not critical to the nature of the invention , and sections 12 and 10 may be of different longitudinal dimensions . the center core 2 of the mattress 21 is constructed of a high resilience foam of medium density . the best mode of the invention calls for use of material with a resilience in approximately the 18 to 23 pounds 25 % ild range and a density of 2 and 1 / 2 to 3 pounds per cubic foot . at its thickest point the center core 2 should be about 5 inches . above this lower limit , the thickness of the center core is dependent on economic constraints and the availability of materials . as shown in fig4 the center core 2 is contoured to form a concave arc 8 which defines a portion of the arm well 9 ( fig1 ) of the mattress 21 . the concave arc 8 rises from the head edge 17 of the core 2 across its lateral axis to form a ridge 15 with the intersection of an inclined plane rising up with a uniform gradient from the longitudinally opposite , or foot , edge 16 of the core 2 . the ridge 15 forms the thickest point of the core 2 . in the best mode , this is about five inches thick and the differential in thickness between the ridge 15 and top of the foot edge 16 is about one inch . it is to be understood , however , that this thickness and differential are not critical to the present invention . fig2 shows one embodiment of the base 22 . the components 3 , 4 , and 5 of base 22 are composed of high resilience , low density foam . the best mode of the invention calls for use of material with a resilience in approximately the 50 to 70 pounds 25 % ild range and a density of 1 . 8 to 2 . 2 pounds per cubic foot . at its thinnest point the base 22 should be about 2 inches . above this lower limit , the thickness of the center core is dependent on economic constraints and the availability of materials . the base 22 may consist of one or a plurality of sections such as shown in fig2 in exploded form . in the preferred embodiment of the invention , the base 22 consists of three section 3 , 4 and 5 . in one embodiment , the head section 3 is connected to the core support section 4 by a fastener 23 such as mating velcro or generic hook and loop fastener strips 23a and 23b , as shown in fig4 although other fastening techniques such as interlocking foam parts or such means as are generally known in the industry may be used . the foot section 5 is connected to the opposite edge of the core support section 4 also by appropriate fastening means , as also shown in fig4 . it is to be understood that while three sections 3 , 4 , and 5 are shown , the base 22 may be constructed of one or more sections . the mattress 21 is assembled as shown in fig3 . the head section 3 core support section 4 and foot section 5 of the base 22 are connected by fastening means 23a and b as shown in fig4 . the center core 2 is placed on the assembled base contoured side up , such that the concave arc of the head section 3 and the concave arc 8 of the center core 2 define a uniform concave arc 14 ( fig1 ) and that the opposite edge of the center core 2 abuts the vertical inner faced edge 5 of foot section . the top layer 1 which is flexible , is placed on the base 22 and center core 2 assembly , conforming to the contours of the upper surface of the base 22 and center core assembly . an arm well 9 ( fig1 ) is formed on the upper surface of the top layer 1 above the uniform concave arc formed by head section 3 of the base 22 and the center core 2 . a firm zone is formed on the upper surface of the top layer above a portion 13 of the foot section 5 of the base 22 which abuts the center core 2 and directly supports the top layer 1 . the arm well 9 is defined by the curvature of the arc formed by 8 and 7 on the upper surface of the top layer and is adapted to accommodate the average human body length from the top of the head to the bottom of the shoulder joint . the arm well 9 allows the shoulder and arm to lie below the torso or chest cavity , thus allowing less restriction on the arms &# 39 ; vascular systems and less strain on the muscles , tendons , bones and shoulder joint . the arm well 9 allows for no less than about five degrees of inflection for the shoulder joint . this is accomplished by the drop in elevation on the upper surface of the top layer 1 above ridge 15 to the bottom of arm well and the uniform change in elevation above the foot edge 16 of center core 2 and the ridge 15 . in the best mode of the present invention , this uniform change in elevation causes the ridge 15 to rise about one inch above the top of the foot edge 16 . the elevation increase along an approximately uniform gradient between ridge 15 and foot edge 16 allows for greater compliance for the upper torso as well . said uniform gradient further provides increased gravitational resistance in the chest region of a person in the prone , sublime or side position to prevent hammocking of the mattress . the arm well 9 is positioned such that it also allows for proper posture for a person sitting at the head end of the mattress by conforming to the shape of the buttocks and an elevation of the knees thereby relieving pressure from the spine . along the foot end of the mattress , there is a translateral firm zone consisting of the high density , low ild foam in the top layer 1 supported by and transitioning to the low density , high ild foam of the foot section 5 of the base 22 within the upper 20 % to 30 % of the overall height of the mattress . accordingly , the thickness of the top layer 1 is about 20 to 30 % of the overall mattress height . this transition allows for vascular conformity for the feet of a person in the prone , sublime or side position and maintains sufficient support for use of the mattress edge as a seat . the firm zone &# 39 ; s longitudinal dimension above portion 13 of foot section 5 is sufficient to provide proper seating for a person of average size . this firm zone eases the transition in standing up or sitting down from the foot of the mattress , which transition is a common source of injury , including muscle strain . the cover 18 is shown in fig5 . the cover ( 18 is integral to the support , conformity and feel of at least one embodiment of the mattress of the present invention , including the best mode . the cover 18 assists in holding the components of the mattress -- top 1 layer , center core 12 and the base 22 ( as shown in fig1 , and 3 )-- together by wrapping around them much like a fitted sheet . the cover 18 fully encases the upper surface of the of the top layer 1 and the exposed outer edges of the top layer 1 center core 12 and base 22 . the bottom surface of the base , is not more than partially encased by the cover 18 . a cover 18 is used to assist holding the various sections of the mattress 21 together and provides additional support for the mattress against deformation when subjected to a load . one embodiment of the cover of the mattress of the present invention , includes a cover tensioning system 20 ( fig6 ). as shown in fig5 a the cover tensioning system utilizing a draw string 24 extending through at least one opening 26 of a sleeve 27 contained along the outer edge of the cover 18 to tighten said cover 18 around the components of the mattress . the cover tensioning system 20 utilizes a cam cleat 25 to hold the draw string 24 at any set tension thereby allowing the user to adjust the mattress 21 for firmness and softness . although a sleeve , drawstring and cam cleat are show , it is to be understood such is not necessary to the present invention and that any suitable method know in the industry as using straps attached to the cover can be used . the cover tensioning system 20 can be used to adjust the feel , i . e ., firmness , of the mattress . when tension in the draw string 24 is increased , the cover is drawn tighter around the mattresses foam components 1 , 2 , and 22 . like filling a balloon with air , the outer surface become firmer due to the increased pressure caused by the resilience of the foam components . the increased tension in the cover 18 also increases the rigidity of the base 22 and causes its outer edges to rise up toward the top of the mattress causing the cover 18 to stretch tight across the top surface . as shown in fig6 the cover 18 has two zones 19a and 19b that are approximately 3 inches wide , on the top of the cover 18 that run the length of the cover . the two zones 19a and 19b are less compliant than the rest of the cover 18 . the zones 19a and 19b can be made by doubling up the density of fabric , by use of fill , or by use of a combination of fabric and fill or by adding a banding material of similar or dissimilar material to the cover 18 . these less compliant zones increase the firmness of the top surface so that the user can recognize the edge of the mattress , and prevent themselves from unintended transitioning out of bed while sleeping . the cover is made of materials that can be domestically washed . unlike conventional mattresses with upholstery , the mattress 21 and cover 18 of the present invention are domestically washable . further , if the mattress assembly wears out , only certain components need be replaced , not the whole mattress . fig7 shows an exploded view of the packaging a plurality of components of the base 22 . although three components 3 , 4 and 5 are shown , it is to be understood that three components are not necessary to the present invention . the intermediate section 4 is placed on top of the head section 3 abutting the elevated contoured section 7 . the foot section 5 is inverted and placed on top of the upper surface of the layered head section 3 and intermediate section 4 . the head section 3 and the foot section 5 being arranged such that they form an essentially uniform outer surface of the layered components . the layered components are then placed within a box 28 with internal dimension approximately equal to the dimensions of the external surface of the layered base components . fig8 shows an exploded view of the packaging of the top layer of the mattress 1 , the middle layer of the mattress 2 and the cover 18 . the middle layer of the mattress is folded and vacuum packed within a bag 29 . the best mode of the present invention is to make two folds to the middle layer 2 . the top layer 1 is folded and vacuum packed within a bag 30 . the best mode of the present invention is to make two folds to the top layer 1 . the cover is folded and vacuum packed within a bag 31 . although the folds to the cover 18 are shown as a roll , it is to be understood that rolling the cover 18 is not essential to the present invention . the middle layer 2 , the top layer 1 and the cover 18 are then placed within a box 32 with internal dimensions approximately equal to the outer surface dimensions of the middle layer 2 , the top layer 1 and the cover 18 stacked on top of each other . the preferred embodiment of the queen and king type sized mattresses , not shown , have two sets of top layers , central core , and bases , side by side , making up one mattress . these independent sides allow for individual firmness and softness , by making the center core softer or firmer and / or by the adjustment of the cover tensioning system . further , this design recognizes the fact that person &# 39 ; s body change temperature , expel moisture , and transition at different rates . increased comfort and reduced sleep disturbance is achieved through the use of two independent sides which isolate the anatomical and physiological differences of two bodies sharing the same bed .
a mattress is provided with elevated chest support region and an arm well to reduce sleep disturbance in a person in the prone , sublime or side position . said mattress is further provided with a firm zone at the foot of the mattress to assist persons transitioning onto and off of the mattress . an adjustable cover for said mattress is provided as is an improved method for packaging said mattress and cover .