Mattress and supporting structure therefor

A mattress is positioned on a flexible deck which is supported by tension members connected to a frame. In a preferred embodiment, the frame is formed of concave side rails, a horizontal head rail, and a horizontal foot rail. The upper surface of the deck is longitudinally concave and transversely convex. The mattress is tapered so that its upper surface is transversely and longitudinally crowned to counteract any potential sagging effect when a person lies on the mattress.

BACKGROUND OF THE INVENTION 
This invention relates to beds, and it particularly relates to improvements 
in mattress configurations and the decks and related structures for 
supporting mattresses. 
The principal applicability of the invention is in storable bed structures 
such as sofa sleepers, rollaway beds, bunk beds and cabinet beds. Modern 
lifestyles often involve smaller homes, modest condominiums and 
apartments. This has created an increasing utilization of storable units 
that convert into beds. Previously, when such storable beds were used only 
for occasional guests, the comfort of such units was of secondary 
importance; however, as such units are now being used more frequently on a 
daily basis, the need for acceptable comfort levels is much greater. 
A storable bed unit normally uses a thin mattress with flat upper and lower 
surfaces. The mattress is supported on a deck which has its perimeter 
connected to a foldable peripheral frame by means of helical springs or 
other tension elements. The decks are normally formed of a flexible metal 
mesh called "link fabric" or a textile fabric which has border wires sewn 
therein, an example of the latter being disclosed in my U.S. Pat. No. 
4,326,260. Frames may be formed of tubular metallic sections, metal angles 
or a combination of such components. 
A recognized problem of storable bed units is that they tend to sag or 
"hammock" to the center of the sleeping surface. This is particularly true 
in units where mattresses are very thin because they are required to fold 
into three thicknesses. The industry has recognized that there are glaring 
deficiencies in the sleeping comfort of such units, resulting in the 
rejection of such units at the retail level. 
A number of solutions have been proposed to the sagging problem. One 
proposal is to increase the thickness of the mattress, but this introduces 
additional problems with respect to units such as sofa sleepers. The 
increased mattress thickness may raise the seating height to an 
unacceptable level. Due to the floor clearances required for the 
mechanisms of such units, thicker mattresses may require an increase in 
the front-to-rear depth of the unit to an extent which is aesthetically 
unacceptable. 
Other efforts to avoid or diminish the sagging problem have involved an 
increase in the deck tension by adding tensioned wires, straps, rubber 
webbing or extra helical springs. It has also been proposed to modify the 
mattress structure so that it has areas of varying compressibility or 
density. These efforts add to the cost of such units and they have been 
used to some degree with limited results. 
Another approach has been to provide the units with transverse wooden slats 
which are bowed upwardly. Beds of this nature have not been introduced in 
this country, at least to any significant extent, probably due to the 
increased cost of such construction. Another proposed but costly solution 
is to provide a deck which has a localized depression in the buttock area, 
and to provide a mattress with a localized protruberance on its lower 
surface for insertion in the depression. 
It is believed that the present invention offers a superior solution to the 
sagging problem. It is superior in the sense that it does not increase 
significantly the cost of manufacture of the components of the system. In 
a sofa sleeper unit, the invention provides improved comfort during sleep 
while, at the same time, providing acceptable seat height, acceptable seat 
pitch, and acceptable travel clearances relative to the floor without 
significantly increasing the front-to-rear depth of the unit. 
SUMMARY OF THE INVENTION 
In one respect, the invention involves a mattress configuration wherein the 
mattress has an area of maximum thickness at a location which is spaced 
inwardly from its longitudinal edges or its transverse edges. The mattress 
has its minimum thickness at its perimeter, and a taper which extends from 
the area of maximum thickness to the area of minimum thickness. The upper 
surface of the mattress is generally smooth in the respect that it has no 
localized depressions and no localized protrusions for accommodating the 
anatomy of a person sleeping thereon. 
In another respect, the invention relates to a mattress which has an upper 
surface of substantial convexity which extends substantially entirely 
across the mattress in a longitudinal and/or transverse direction when the 
lower surface of the mattress is located in a horizontal plane. The 
mattress is thinner near at least one pair of its edges than it is in its 
central area. 
The invention involves, in a further respect, a deck for supporting the 
mattress. This deck has an upper mattress supporting surface which in 
transverse planes is convex and in longitudinal planes is concave. 
There are a number of additional features which contribute to the 
desirability of the present invention. For example, the deck is preferably 
supported by tensioning members connected to a peripheral frame which has 
horizontal head and foot rails, and concave side rails which, acting 
through the tensioning members, provide the shape to the mattress 
supporting surface. As will be apparent from this specification, the terms 
"concave" and "convex" are used in a broad sense to encompass curved 
shapes and shapes which are formed of plural linear segments so that they 
are, in effect, bowed or bent inwardly or outwardly. The longitudinal 
concavity of the deck is greatest at the sides of its mattress supporting 
surface, and this concavity decreases progressively toward the center of 
the mattress supporting surface. In transverse planes, the concavity of 
the deck is greatest at a midportion of the deck and it decreases 
progressively toward the head and foot of the deck. 
The frame is formed of sections which are pivotally connected together to 
permit the frame to be folded from a sleeping position to a collapsed 
position. The longitudinal tension in the deck is greater when the frame 
is in the sleeping position than when the frame is in the collapsed 
position, and this feature reduces the transverse convexity of the deck 
when the frame is in the collapsed position. Preferably, the lower surface 
of the mattress is convex in longitudinal planes and concave in transverse 
planes. 
The foldable deck-supporting frame may be connected to and supported by an 
upholstered furniture frame. 
As to the configuration of the mattress, its minimum thickness is 
preferably located at the head and foot, i.e. the transverse edges of the 
mattress. In each transverse plane through the mattress, the mattress is 
upwardly convex and its thickness is substantially constant. The mattress 
is tapered in longitudinal vertical planes, but not in the transverse 
vertical planes. When the mattress is positioned on the deck, the upper 
surface of the mattress preferably has a convex curvature extending both 
longitudinally and transversely of the mattress. 
The invention also pertains to various combinations of specified mattress 
configurations, deck configurations, foldable deck-supporting frames, and 
upholstered sofa frames.

DESCRIPTION OF A PREFERRED EMBODIMENT 
FIG. 1 shows a rectangular frame 2, a mattress-supporting flexible deck 4 
which is connected to the frame by tension springs 6, and a mattress 8 
which is normally supported on the deck 4. To illustrate the mattress 
configuration, a quadrant thereof is broken away to show transverse and 
longitudinal sections 10 and 12 of the mattress. 
The upper surface 14 of the mattress 8 has a convex curvature which extends 
entirely across the mattress, both in transverse and longitudinal vertical 
planes. The center of the upper surface 14 is at least about 3/4 inch 
higher than the edges of the upper surface. This upper surface 14 is 
smooth in the respect that it has no localized depressions and no 
localized protrusions for accommodating the anatomy of a person sleeping 
thereon. The smooth upper surface 14 may be quilted in a known manner to 
provide an ornamental pattern in relief and intaglio. The mattress is 
rectangular, and its perimeter is defined by a pair of longitudinal side 
edges 16 and 18 and a pair of transverse edges 20 and 22 which are located 
at the head and foot of the mattress. 
In FIG. 1, the mattress has the shape it assumes when supported on the deck 
4. When the mattress is supported on a flat surface so that its lower 
surface conforms to and is in a horizontal plane, its upper surface has a 
substantial convexity which extends substantially entirely across the 
mattress in a longitudinal direction. When it is supported on a flat 
horizontal surface, the mattress has no transverse convexity. The mattress 
is thinner near its head and foot than it is in the central area which is 
spaced inwardly from the longitudinal and transverse edges of the 
mattress. 
In the embodiment of FIG. 1, the maximum thickness of the mattress is 
located approximately midway between the head and foot. The areas of 
minimum thickness are at the head and foot of the mattress. As shown by 
the longitudinal sectional surface 12, a taper extends from the area of 
maximum thickness to the area of minimum thickness. The area which 
represents the cross section of greatest thickness is, in the transverse 
plane of section 10, untapered and upwardly convex. The lower surface of 
the mattress conforms to the configuration of the mattress supporting 
surface of the deck. The lower surface of the mattress is concave in 
transverse planes so that the section 10 has a substantially constant 
thickness. In longitudinal planes, the lower surface of the mattress is 
convex. The maximum transverse concavity and the minimum longitudinal 
convexity are seen in the respective sections 10 and 12 in FIG. 1. The 
transverse concavity of the lower surface decreases progressively from the 
section 10 toward the head and toward the foot of the mattress. The 
longitudinal convexity of the lower surface increases progressively from 
the section 12 toward the side edges of the mattress. 
The mattress is supported on the deck 4 which, as mentioned above, is 
supported by tension members 6 which are connected to the frame 2 which 
extends around the deck. The deck 4 is formed of a textile fabric, metal 
link fabric, or any other suitable material. The frame 2 has a horizontal 
head rail 24, a horizontal foot rail 26, and upwardly concave side rails 
28 and 30. The frame 2 is preferably foldable for convenience of storage. 
The forces exerted on the deck by the tension members 6 provide the shape 
to the upper mattress-supporting surface 32 of the deck. In transverse 
planes, the mattress supporting surface of the deck is convex: whereas, in 
longitudinal planes, the mattress supporting surface of the deck is 
concave. The maximum transverse concavity of the deck is greatest at the 
midportion of the deck as shown by the broken line 34. This transverse 
concavity decreases progressively toward the head and foot of the deck. 
The longitudinal concavity of the deck is greatest at the sides of the 
mattress supporting surface 32. This concavity decreases progressively 
toward the center of the mattress supporting surface. The location of the 
minimum longitudinal concavity is at the line 36 shown in FIG. 1. 
From the foregoing, it will be understood that the springs 6 provide 
connecting means on the frame for subjecting the flexible deck to 
substantially horizontal tensile forces in longitudinal and transverse 
directions. This gives the concavity and convexity to the mattress 
supporting surface of the deck when there is no vertical load on the deck. 
The substantially horizontal tensile forces which act in transverse 
directions are disposed along lines which are concave and lie in vertical 
longitudinal planes on opposite sides of the deck. 
FIGS. 2 and 3 illustrate the manner in which the invention improves the 
characteristic of the bed. In these drawings, the broken lines 38 and 40 
represent the initial unloaded position of the upper surface of the 
mattress, whereas the broken lines 39 and 41 show the initial unloaded 
positions of the desk and lower surface of the mattress. The upper surface 
is convex so that it is crowned both in the longitudinal section shown in 
FIG. 2 and the transverse section shown in FIG. 3. When a person lies on 
the bed, the deck and the mattress deform to the positions shown in solid 
lines. In FIG. 2, it will be noted that the buttocks area is located in 
the vicinity of the maximum thickness of the mattress which naturally 
provides a greater cushioning effect. Further, the upper surface 14, 
rather than sagging, becomes somewhat horizontal when loaded. 
In FIG. 3, the occupant is shown in a position which is offset to one side 
from the longitudinal centerline of the mattress. Nonetheless, the upper 
surface 14 of the mattress is generally horizontal so there is no 
significant tendency for the upper surface to sag to a point that the 
occupant will tend to roll toward the longitudinal centerline of the 
mattress. 
The invention is suited for use in connection with a wide variety of 
bedding frames. For example, FIG. 4 shows a rollaway bed in which the side 
rails are formed of three pivotally interconnected sections. The 
midsection 42 is substantially horizontal and is supported on a pair of 
legs 44 and 46 which are provided with casters. Extending forwardly and 
rearwardly from the midsection are the side rail sections 48 and 50 which 
are supported on legs 52 and 54 when the bed is in the sleeping position 
shown in FIG. 4. These forward and rearward side rail sections 48 and 50 
are inclined slightly upwardly toward the head and foot of the bed, 
thereby providing the concave configuration which has essentially the same 
effect as the frame illustrated in FIG. 1. The mattress 8 is folded to the 
elevated storage position in a conventional manner by swinging the side 
rail sections 48 and 50 upwardly on pivots 49 and 51 until the mattress 
arrives at the position shown in broken lines. 
In each of the embodiments shown in FIGS. 5 and 6, a foldable frame is 
connected to an upholstered sofa frame, and the side rail of the foldable 
frame comprises a plurality of pivotally interconnected sections which 
permit the frame to be folded from a sleeping position to a collapsed 
storage position. When in the collapsed position, the frame occupies a 
storage position where it is housed in the furniture frame. When extended, 
the foldable frame occupies a generally horizontal sleeping position where 
it extends from the furniture frame. 
The frame 56 shown diagrammatically in FIG. 5 is supported by links which 
are connected to the upholstered sofa frame 57. One such link is 
schematically illustrated by a broken line 59. The side rails in this 
embodiment are formed of four sections 58, 60, 61 and 62 which are 
pivotally connected to each other at the pivots 64, 65 and 66. Auxiliary 
support legs 68 and 70 have their upper ends pivotally connected to the 
side rails. In a conventional manner, the frame is folded by folding the 
side rail sections to a collapsed position where they form a cavity for 
storing the mattress. The folded mattress 8 occupies the position in the 
furniture frame which is shown in broken lines. In this position, the 
mattress is folded into three sections, one of which is generally 
vertical, and two of which are generally horizontal. The folded 
configuration of the frame components around the mattress is shown in FIG. 
7. It will be noted that the tapered configuration of the mattress 
provides its upper surface with a slight rearward pitch. When loose 
seating cushions are placed on the folded mattress, the sofa sleeper has 
the appearance and comfort of a conventional sofa. 
The sofa sleeper shown in FIG. 6 uses a somewhat different frame and 
storage principle than the one shown in FIG. 5. In FIG. 6, the broken line 
71 indicates diagrammatically that the deck supporting frame is connected 
to the upholstered sofa frame. The side rail sections 72,74, 76, 78 and 80 
are pivotally connected together at pivot points 82, 84, 86 and 88. The 
auxiliary support legs 90 and 92 have their upper ends pivotally connected 
to the side rails. The articulated side rail makes it possible to fold the 
frame and a mattress therewithin to the position shown in broken lines in 
FIG. 6, where the mattress is in three generally horizontal sections. The 
folded configuration of the frame components around the mattress is shown 
in FIG. 8. In this arrangement, loose, tight or semi-attached back 
cushions are provided. Conventional seating cushions are placed on the 
folded mattress to provide a comfortable and attractive article of 
furniture. 
To avoid excessive transverse convexity which would be detrimental to the 
appearance of the sofa when the mattress is stored therein, the frames 
shown in FIGS. 5 and 6 are arranged so that the deck supported thereby 
will have more longitudinal tension when the frame is in the sleeping 
position that when it is in the collapsed storage position. Due to this 
arrangement, the transverse convexity is reduced when the frame is in the 
collapsed position. 
The mattresses used in connection with the invention will generally be of 
conventional length and width ranging from a size of about 27.times.48 
inches to a size of 84.times.84 inches. The maximum and minimum 
thicknesses of the mattresses will be about 81/2 inches and 13/4 inches, 
respectively. The mattress may be of innerspring or foam construction, and 
it may be made by existing technology. In a foam mattress, the crowned or 
tapered shape is due to the initial thickness of the foam before the 
mattress cover is applied. In the case of an innerspring mattress, the 
desired shape may be a result of the height of the rows of spring coils 
and/or the initial thickness of the filler materials before the cover is 
applied. 
The preferred versions of the invention have been illustrated, but it 
should be kept in mind that alternative arrangements are contemplated 
within the scope of the broader claims which are presented below. For 
example, in one possible modification, the mattress supporting surface of 
the deck may be horizontal in all transverse planes, and concave in all 
longitudinal planes. The concave configuration may be a shallow Vee. The 
mattress in this arrangement will have an upper surface which is planar, a 
lower surface which conforms to the deck, and a thickness which has its 
maximum at or near the mattress transverse centerline. The principal 
advantage of this construction is that the mattress will be thicker in the 
buttocks area. This particular deck configuration is not possible when 
using a shaped support frame and a tensioned deck. 
Another unillustrated modification utilizes a planar deck which may be 
supported by perimetrical tension members connected to a perimetrical 
frame. The mattress has its maximum thickness at or near its transverse 
centerline, and it tapers to a minimum thickness which is at the head and 
foot of the mattress. This construction is comfortable in the center, but 
it is less comfortable toward the sides of the bed because of the 
excessive thickness near the sides of the mattress. 
Still another configuration utilizes a planar deck which is supported by 
perimetrical tension members and a perimetrical frame. This differs from 
the previous embodiment in that the mattress of this version tapers both 
in longitudinal and transverse directions from a point of maximum 
thickness which is located at or near the intersection of the transverse 
and longitudinal centerlines of the mattress. This arrangement is 
comfortable for sleeping purposes but, it looks relatively thin and it is 
not as cost efficient from a manufacturing standpoint as the mattress 
shown in FIG. 1. 
The mattress may be of foam or innerspring construction. It can be of one 
piece construction as shown, or it can be formed of two or more pieces 
which are stacked to form the claimed configuration. 
Various linkages, well known in the furniture industry, may be used to 
control the movements of the sections of the foldable frames disclosed in 
this specification. Examples are disclosed in U.S. Pat. No. 4,301,559 
issued Nov. 24, 1981 and U.S. Pat. No. 4,439,878 issued Apr. 3, 1984. A 
more recent but referred linkage is disclosed in U.S. Pat. No. 4,592,102 
issued June 3, 1986. The disclosures of these three patents are 
incorporated herein by reference. 
Rather than using helical springs to tension the deck, it is possible to 
use elastomeric members or inelastic means such as eye bolts or tangs 
which connect the frame to the perimeter of the deck. The deck may be a 
fabric of woven stretch oriented members which is shrunk by heating after 
it is connected to the frame. 
Persons familiar with the art will recognize that this significant 
invention may take many forms. Therefore, it is emphasized that the scope 
of the invention is not limited to the disclosed embodiments but is 
embracing of a wide variety of structures which fall within the spirit of 
the following claims.