Note: Descriptions are shown in the official language in which they were submitted.
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Foam construction and mattress or pillow provided
therewith.
The present invention relates to a foam construction and a
mattress provided therewith.
More specifically, the invention concerns a foam
construction of flexible synthetic foam that is very
suitable for forming the base of a mattress.
A very important property of a mattress, that determines
the comfort of a mattress, is the extent to which heat and
perspiration moisture can be removed from the surface on
which the user lies, so that a mattress does not feel too
warm and clammy while sleeping.
It is especially important for restful REM sleep to have a
relatively low body temperature from the start of the
sleep, i.e. good heat removal.
As is known many mattresses are made from relatively soft,
flexible synthetic foam, such as latex or PUR on account of
the relatively low cost and the easy processing of them.
These synthetic foams exist in a normal elastic variant and
a viscoelastic variant.
However, these foams have the disadvantage that they have
relatively small pores in which air is trapped, such that
there is only a slow circulation of air, such that the heat
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removal and removal of perspiration moisture from a
sleeping person is often not optimum. As a result optimum
sleeping comfort is difficult to achieve, and mould and
bacterial growth can occur in the mattress.
Large open cell foams are indeed known, but they may not be
thicker than 1 to 2 cm in a mattress so that they do not
prevent air circulation. However, with such a low thickness
these foams provide insufficient elasticity to make a good
mattress.
A special class of such foams for mattresses are the
viscoelastic foams.
They have very attractive properties regarding the
suspension and support of the body of the user, because
they can absorb large quantities of energy and only release
it again slowly, such that the body of the user is well
supported over a large area. As a result they are much used
in hospitals for example to prevent bedsores, but also for
home use on account of their comfortable supporting nature.
However, these foams have the disadvantage that the speed
with which the air is allowed through is even slower than
with the above-mentioned elastic foams, because they have a
relatively high fraction of closed pores.
As a result they feel very warm and the user can feel
uncomfortable as a result of the poor moisture removal, and
for bedridden people can even lead to other types of skin
problems.
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With spring mattresses more air circulation is of course
possible around the springs, but the exchange of air with
the surface on which the user lies is impeded by the
necessary presence of a covering over the springs.
In brief, with existing mattress constructions good
ventilation of the surface on which the user lies is not
possible, so that perspiration moisture and warm air
accumulate in the mattress, and sleep can be interrupted or
is less restful.
The purpose of the present invention is to provide a
solution to the aforementioned and other disadvantages by
providing a mattress that is provided with two or more foam
constructions placed next to one another sideways, that
each comprise a base extending in a longitudinal direction
whereby this base is made of a flexible synthetic foam and
this base comprises two arms extending in the longitudinal
direction, that are connected, preferably at their ends, by
a breathable bridge that extends in the said longitudinal
direction, whereby the bridge is oriented upwards.
For completeness it is noted that the longitudinal
direction is generally, but not necessarily, the largest
distance over which-a said foam structure extends, but is
the direction in which the cross-section of the base does
not or not significantly change.
For clarity it is emphasised that the base as a whole, the
arms, and the bridge extend in the longitudinal direction,
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i.e. these components are present in an unchanging mutual
configuration over a certain distance in the longitudinal
direction.
Hereby the bridge can be made of foam, but the bridge can
also be made of other materials, such as a breathable
textile or a knitted 3D fabric.
Normally speaking the bridge is a flat structure that
extends in the longitudinal direction and in a direction
perpendicular to it in order to bridge the entire space
between the arms.
In a preferred embodiment the bridge is provided with
passages.
In a further preferred embodiment the base is not provided
with passages.
These passages guarantee sufficient breathability of the
bridge.
Thanks to the breathable bridge such a mattress provides
very good air circulation, because perspiration moisture
from the user can be removed well from the surface on which
the user lies.
This proceeds via induced ventilation. This means that due
to the heating of the air in the mattress close to the body
of a sleeping person, an upward airflow comes into being
via the breathable bridge.
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Fresh air comes into the mattress sideways, via the space
between the arms of the foam constructions, and this air is
again heated so that permanent good ventilation with fresh
air, and the removal of warm air with perspiration moisture
5 therein, is obtained.
Thanks to the arms and the bridge, there are two different
types of foam components that a mattress designer can adapt
to obtain the desired body-supporting properties, so that
the foam construction provides great flexibility for a
mattress designer.
In a preferred embodiment the bridge is made of
viscoelastic foam.
As a result the above-mentioned attractive properties of
viscoelastie foam can be combined with good ventilation
properties obtained by the specific foam construction and
mattress construction.
In a further preferred embodiment the base is made of non-
viscoelastic foam. This enables a relatively sturdy, i.e.
not too soft, foam construction to be made with a low cost
and a low weight.
In another further preferred embodiment the bridge is made
of a strip of foam that is provided with cuts, whereby the
base is arranged to exert a tensile force on the bridge
such that the cuts are pulled open, and thereby form the
said passages.
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This gives the entire foam construction a better elastic
.character. Moreover; this enables relatively small cuts to
be made but with relatively large passages obtained, so
that there is little or no material loss. Also, such a
bridge under tension ensures that the passages are not
pushed closed by a deformation of the bridge, as can occur
when a person lies on the mattress.
In a further preferred embodiment the cuts, when the bridge
is in an unstretched state, are linear incisions.
Hereby an incision means that no material is removed when
it is made, such that the cut surfaces of a volume with an
incision fit precisely together, while a cut comprises
supplementary openings that are made by removing material
and where the cut surfaces of a cut volume do not fit
together precisely.
By making cuts in the form of an incision, it results in no
material loss such that no foam is lost and the cuts can
also be made with simple tools.
In a preferred embodiment the base comprises precisely two
arms that are parallel to one another, that are at a
distance from one another, and which extend over the
length, and preferably over the entire length, of the foam
construction, such that a channel is formed between the
arms that extends in the said longitudinal direction.
In a preferred embodiment, the base, in a cross-section
transverse to the longitudinal direction, is U-shaped or V.-
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shaped with a back and two arms. The back hereby connects
the. two arms at the other side than the bridge, so that the
foam construction is tubular.
Compared to a full foam layer, such a tubular construction
is lighter and uses less material. A tube is also open at
its ends such that fresh air can freely flow into the
mattress.
In another preferred embodiment the base is formed by a
strip or sheet of foam that is bent into a V-shape or U-
shape, and is thereby under a bending stress and which, due
to its elasticity, in other words due to this bending
stress, can exert a tensile force on the bridge.
It goes without saying that the bridge hereby exerts a
tension on the V-shaped or U-shaped bent strip of foam so
that it remains V-shaped or U-shaped.
The width and dimensions of the bridge and the spring
characteristics of the strip of foam and the bridge hereby
together determine the shape of the foam structure.
This is an easy way to make such a foam construction.
In a preferred embodiment the foam constructions are glued
or welded together sideways. This means that an arm of a
foam construction is glued or welded to one of an adjacent
foam construction.
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This has the advantage that a downward load, that results
'in a sideways bulging of the arms, is transmitted to
adjacent foam constructions, such that such a combination
of foam constructions presents much more sturdiness than a
separate foam construction, and has a very good elastic
behaviour with a relatively small quantity of foam.
Alternatively they can glued be individually, arranged
side-by-side onto a bottom plate, or if applicable to a top
plate of very breathable material.
In a further preferred embodiment the said longitudinal
direction of the foam constructions is transverse to the
direction from the head end to the foot end of the
mattress. This has the advantage that different zones of
the mattress can be constructed with different properties
in order to be better suited to the different zones of the
human body.
In a further preferred embodiment the mattress is provided
with means to actively impose an airflow in the space
between the arms of at least one of the foam constructions.
On account of the foam constructions placed next to one
another, which as it were form individual channels, a
mattress provided with the foam constructions is extremely
suitable for connecting some or all channels to an air pump
or air extraction system, in order to, if necessary,
further imprOve the air circulation and the moisture
removal, but also in this way to provide the mattress with
heating or cooling.
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The invention also comprises a cushion, i.e. a pillow,
lounger cushion or hassock, that is provided with two or
more foam constructions placed next to one another sideways
as described above, whereby preferably the bridge is
oriented upwards, i.e. towards the side that is intended to
come in contact with a person.
The invention further comprises the foam construction
described above for use in a mattress or pillow, hassock or
lounger cushion.
With the intention of better showing the characteristics of
the invention, a preferred embodiment of a foam
construction and a mattress according to the invention is
described hereinafter by way of an example, without any
limiting nature, with reference to the accompanying
drawings, wherein:
Figure 1 schematically shows a perspective view of a
foam construction according to the invention;
figure 2 schematically shows a perspective view of a
mattress core of a mattress according to the
invention;
figure 3 shows the part of figure 2 designated by F3
on a larger scale;
figures 4 and 5 show successive steps in the
manufacture of the foam construction of figure 1;
figure 6 schematically shows a perspective view of a
mattress core of an alternative mattress according to
the invention;
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and figure 7 shows the part of figure 6 designated by
F7 on a larger scale.
The foam construction 1 shown in figure 1 is tubular and
5 extends in the longitudinal direction indicated by L.
The foam construction 1 has a width B, in this example but
not necessarily of 10 cm and a high H, in this example but
not necessarily of 15 cm.
The foam construction 1 consists of two components
connected together by means of glueing, i.e. a bent U-
shaped base 2 with a back 3 and two arms 4 and a straight
strip of foam that forms a bridge 5 between the arms 4.
The base 2 is made of a strip of flexible non-viscoelastic
PUR foam, which in this example but not necessarily has a
thickness D1 of 25 mm and which is bent into a U-shape so
that the arms 4 exert a slight tensile force on the bridge
5 oriented towards the outside.
The bridge 5 is made of viscoelastic foam, in this example
with a thickness D2 of 20 mm and is provided with a regular
pattern of passages 6 between the top of the bridge 5 and
the space 7 between the arms.
The passages 6 are rhombic and in the longitudinal
direction L form running discontinuous lines 8 that are
staggered with respect to one another.
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The bridge 5 is kept somewhat under tension by the arms 4
of the base, such that the passages 6 are pulled open,
which is the case to a greater extent near the centre than
closer to the arms 4. The bridge 5 hereby prevents the arms
4 from springing outwards, but keeps them in the desired
position.
As shown 'in figures 2 and 3 a mattress can easily be
manufactured from the foam constructions 1 described above.
It is hereby noted that only a mattress core 9 is shown in
figures 2 and 3. In order to make a mattress from this
mattress core, it is sufficient to provide a textile cover
to enclose this mattress core 9. Optionally, supplementary
top or bottom layers can be provided within the said cover.
It is hereby necessary for the sides to remain open enough
in order to enable a good inflow of air.
The mattress core 9 of figures 2 and 3 essentially consists
of a number, in this example twenty, of the foam
constructions 1 described above that are all manufactured
or cut to the same length L, corresponding to the width of
the mattress core 9.
The foam constructions 1 are placed next to one another
sideways, with the bridges 5 oriented upwards and glued
together at the location of the arms 4 located next to one
another on a bottom plate 10 of flexible foam.
The longitudinal direction L of the individual foam
constructions 1 hereby runs in the crosswise direction of
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the mattress core, thus in the direction perpendicular to a
line from the head end 11 to the foot end 12. -
Air can now move freely between the surface against which a
user lies and the environment, through the passages 6 in
the bridge 5 and via the channels formed by the space 7
between the arms 4 of each foam construction 1.
As a result of the body heat of the user an airflow can be
induced that is upwards at the location of the passages 6,
so that fresh surrounding air is permanently supplied from
the environment, and such that it prevents a mattress
formed from the mattress core 9 feeling too warm.
The perspiration moisture of a person who sleeps on such a
mattress is removed with this air to the side of the
mattress and from there to the environment.
This effect is amplified by movements of the user. The
mattress can also be provided with, or connected to, a
device .for blowing or extracting air. Such a device can be
connected at a side of the mattress to each or a number of
the spaces 7 between the arms 4 of individual foam
constructions 1.
It is of course relatively easy, with the method shown for
composing the mattress core, to obtain different elastic
and viscoelastic behaviour in different zones of a mattress
by adapting the thickness and type of the foam layers from
which the base 2 and the bridge 4 are made in a foam
construction 1 used in a zone concerned.
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A foam construction 1, as shown above, can be manufactured
as follows.
A strip of viscoelastie foam intended to form the bridge 5
is provided with a number of straight lines 8 with cuts,
whereby these lines 8 extend in the longitudinal direction
L of the foam construction 1 to be manufactured.
The cuts are made in the form of straight incisions 13,
which means that no material is removed when making them.
Each line 8 with incisions 13 comprises alternating
incisions 13 and non-cut sections, whereby the incisions 13
are made with a regular pitch S. The incisions 13 of lines
8 located next to one another are mutually staggered over a
distance of half the pitch S, so that a regular pattern of
incisions 13 is obtained.
The incisions 13 can be made in many different ways. An
easy way is to use a rotating disk with a number of blades
whereby the strip of viscoelastic foam is guided between
this rotating disk and a cutting table.
A strip of foam with incisions 13 thus obtained is shown in
the top part of figure 3.
A straight strip of foam for the base 2 is then bent into a
horseshoe shape, as shown in the bottom part of figure 3.
The distance.A between the sides 14 bent towards one
another is approximately 15 mm.
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A layer of adhesive 15 is applied to the sides 14 bent
towards one another, which after bending form the top of
the horseshoe shape. This can be on a complete side 14 or
only on a part thereof, as shown in figure 3.
Then the strip of foam for the bridge 5 is placed on the
sides 14 bent towards one another of the strip of foam for
the base 2 to until the adhesive 15 has set sufficiently.
This is shown in figure 4.
If no forces are now exerted on the foam construction thus
formed, the arms 4 of the base 2 will bend towards the
outside and thereby exert a tensile force on the bridge 5
such that the incisions 13 are pulled open into rhombic
passages 6, as shown in figure 1, and such that the arms 4
are practically or completely parallel and a foam
construction 1 as shown in figure 1 is formed.
Such a foam construction can be manufactured with a
specific required length L, but can also be manufactured
almost endlessly with an unspecified length, and then cut
to the desired length L.
De alternative mattress core 9 shown in figures 6 and 7
differs from the mattress core 9 described above, because
it is composed of a large number of short foam
constructions 1, in this case with a length L of
approximately 12 cm.
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They are placed next to one another such that a number of
foam constructions 1, in this example seven, are in line
with one another and form a row 16 and a number, in this
example twenty, of such rows 16 are placed next to one
5 another sideways so that a surface is formed to serve as a
mattress core 9.
The mutual distance A between the foam structures 1 in a
row 16 is typically a few millimetres.
Such a mattress core 9 has the advantage that the good air
circulation of the mattress core 9 described earlier is
preserved, while nevertheless a local deformation is not
passed on to adjacent foam constructions 1 in a row 16, so
that the elastic behaviour of the total mattress core 9 is
better suited to accommodate highly different local forces
with highly different local extents of deformation.
Such mattress cores 9 can be manufactured in different
ways.
A possibility is to first manufacture a mattress core 9
according to figure 2, and then to make incisions
perpendicular to the longitudinal direction L of the foam
constructions 1. As a result, the bottom plate 10 can
either be omitted, or cut through as well and sacrificed,
after which a new bottom plate 10 can be provided as in
figure 6.
Another possibility is to first make relatively long foam
constructions 1 as in figure 1, and then to saw them to the
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desired length L, and to put them together into a mattress
core 9.
Of course, short individual foam constructions 1 according
to the invention can also be made from short strips of foam
for the base 2 and for the bridge, but this has the
disadvantage that it requires a relatively large amount of
work.
The present invention is by no means limited to the
embodiments described as an example and shown in the
drawings, but a foam construction and mattress according to
the invention can be realised in all kinds of forms and
dimensions, without departing from the scope of the
invention.
