Note: Descriptions are shown in the official language in which they were submitted.
CA 02529991 2005-12-13
PATENT
OM159
-1-
INFANT MATTRESS
Background of the Invention
The present invention relates to a mamess, and, more particularly, to a
comfortable mattress
for underlying an infant.
In general, with an infant being treated in an infant apparatus or, for that
matter, simply
resting on a piece of furniture, such as a crib or the like, it is intended
that such infant be maintained
in a safe, comfortable environment. To that end, there is normally used an
infant mattress that
underlies the infant for support and comfort of that infant.
There are, of course, a number of requirements for an infant mattress, that
is, it must not
only be comfortable and support the infant, but it also needs to be relatively
easy to manufacture in
order to be commercially viable and also preferably should be anti-microbial.
The mattress should
have a support surface that is developmentally friendly and have as few as
possible pressure points.
At present, many of the existing infant mattresses develop pressure points in
certain areas of the
body of the infant in contact with the mattress because the mattress does not
conform to the body
uniformly in distributing the weight of the patient. The pressure points
result in discomfort and may
produce skin ulcers. As a result, many users of such mattresses use secondary
developmentally
friendly materials to reduce the pressure points with such mattresses.
The normal mattress also should have a cover that is cleanable and comprised
of an anti-
microbial, non-toxic material for the safety of the infant and be cleanable
with all of the normal
hospital disinfectants and should be liquid resistant and not be permeable to
liquid or absorb liquid.
It would thus be advantageous to have an infant mattress having all of the
aforementioned
qualities and yet be easy and relatively inexpensive to produce.
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Summary of the Invention
Now, in accordance with the present invention, there is provided an infant
mattress that is
comprised of a material that is inherently designed to disperse pressure
points and evenly distribute
the pressure load over a large area of the mattress thereby being a good,
developmentally friendly
mattress.
In the construction of the present mattress, there are a plurality of layers
of a foam material,
that is, there is an inner foam layer comprised of an open or closed cell
urethane foam, and with two
outer foam layers comprised of a visco-elastic foam material, which also may
be a urethane foam.
The outer foam layers sandwich the inner foam layer therebetween.
In the present invention, the outer foam layers are of a visco-elastic
material whereby the
foam recovers very slowly from an indentation that is made by a body pressed
into the visco-elastic
material. As such, with an infant positioned on the mattress, the outer foam
layer will more evenly
distribute the weight of the infant over the mattress and avoid pressure
points. As a feature of the
present invention therefore, by having the outer foam layers the same, both
visco-elastic having the
same properties, the caregiver can place the mattress underneath the infant
without the need to make
sure a particular side is facing upwardly to receive the infant. The density
of the outer foam layers
can be in the range of about 1.0 to about S.0 pounds per cubic foot with a
preferred density of about
3.0 pounds per cubic foot.
On the other hand, the inner foam layer is an open or closed cell foam that
has a faster
memory such that the material returns rapidly to its original configuration
when a body causing an
indentation has been removed. The combination of the two outer foam layers
having a slow to
recover material with the inner foam layer having a more rapid recovery rate
brings about the
particularly desirable properties of the present mattress. The density of the
inner foam layer can be
in the range of about 1.0 to about 3.0 pounds per cubic foot and preferably
may have a density of
about 1.7 pounds per cubic foot.
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Despite the aforementioned relative densities of the inner and outer foam
layers, i.e. the
outer foam layers have a higher density than the inner foam layer, however,
the outer foam layers
give more easily than the inner foam layer, the reason being that the outer
foam layers are made of
the visco-elastic material while the inner foam layer is made of the open or
closed cell foam that is
actually stiffer, and gives less easily, than the outer foam layer but is a
less dense foam material.
Accordingly, while the various foam layers can be described by means of their
densities, those
densities are not indicative of the give or firmness of the foam layers
themselves where the different
foam layers are or are not visco-elastic.
The outer foam layers can be preferably mechanically captured and retained to
the inner
foam layer and that mechanical retaining can be earned out through the use of
an adhesive,
stitching, Velcro fastening system or other mechanical securing means. In one
embodiment, an
adhesive is used for the mechanical retaining means and, in the preferred
embodiment, the adhesive
can be in the form of a stripe of adhesive applied only around the outer
periphery of the mating
surfaces of the inner foam layer and the outer foam layers, thereby leaving a
large center area of the
mating surfaces having no adhesive at all. By that technique, the center areas
of the inner and outer
foam layers are free to move with respect to each other.
In the embodiment shown, the shape of the mattress is rectangular, with the
shorter of the
opposite sides being rounded and with the adhesive stripe that is between
about 0.25 and 2.5 inches
in width, preferable about one inch, surrounding the outer periphery of the
mattress. Of course, the
mariress may have other shapes and the adhesive stripe may only extend
substantially around the
outer perimeter of the mattress. The important feature of the particular
affixation of the outer foam
layers to the inner foam layer is that with the use of the perimeter adhesive
stripe, the abutting inner
areas of the various foam layers are free from any adhesive and, therefore,
movement is allowed
between the various layers of the foam material inwardly of the adhesive
stripe. As an alternative,
the can be no affixation between the outer foam layers and the inner foam
layer.
As another feature of the present mattress that may be incorporated into the
construction,
there may be micro-convolutes that are formed on the interior surfaces of the
outer foam layers so as
to extend inwardly to contact both surfaces of the inner foam layer. As such,
the micro-convolutes
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actually contact the surfaces of the inner foam layer in sandwiching the inner
foam layer between
the outer foam layers.
Finally, there is an outer cover the surrounds and encloses the three foam
layers and that
outer cover is comprised of a material that is anti-microbial, cleanable and
non-toxic so as to not
harm an infant positioned thereon as well as liquid resistant. The means of
securing the outer cover
to the layers of foam material can be by a stitching, RF or HF welding,
zippering, Velcro fastening
system or any other suitable means. The outer cover may be removable for
cleaning and can have
one side openable so as to facilitate the insertion and removal of the foam
layers therefrom.
The outer cover preferable surrounds the three foam layers or composite foam
structure with
sufficient clearance around the outer perimeter of the foam layers in order to
allow the foam layers
to expand when the infant is placed thereon and the expanding perimeter is not
restrained by the
dimensions of the outer cover. Thus, the layers of foam can freely expand
under the deformation
imposed by the infant so as to avoid a hammock effect where that expanding
perimeter of the foam
layers is hampered or restrained by the outer cover.
Other features of the present infant mattress and method of making the same
will become
more apparent in light of the following detailed description of a preferred
embodiment thereof and
as illustrated in the accompanying drawings.
Brief Description of the Drawings
Figure 1 is an exploded side view illustrating the layers of foam that are
used to make up the
present mattress;
Figure 2 is a top view of the mattress of the present invention illustrating
the application of
the adhesive stripe;
Figure 3 is a side view of the foam layers of the present invention secured
together; and
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Figure 4 is a top perspective of the mattress of the present invention and
illustrating the
outer cover enclosing the composite foam structure.
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Detailed Description of the Invention
Taking, therefore, Fig. 1, there is shown a side, exploded view of the various
components
that make up the present mattress. As can therefore be seen, there is an inner
foam layer 10 and a
pair of outer foam layers 12 that basically sandwich the inner foam layer 10
therebetween when the
mattress is assembled.
The materials of the inner and outer foam layers 10, 12 are specially selected
to achieve the
overall benefit of the mattress of this invention. Accordingly, the inner foam
layer 10 is an open or
closed cell, elastomeric foam, such as urethane, that is relatively stiffer or
less resilient than the
outer foam layers 12 and can be comprised of a foam such as North Carolina
Foam Ultra Cell UC-
17, having a density of about 1.7 pounds per cubic foot, a resilience (%
rebound) of 59-66 and a
total thickness of about 0.75 inches. The range of thicknesses for the inner
foam layer 10 can be
from about 0.25 inches to about 1.0 inch for suitability as an infant
mattress, however, it can be
understood that different thicknesses would be expected based upon different
uses of the present
mattress. Other parameters of the inner foam layer 10 include a specific
gravity of 0.015 - 0.08 and
insolubility in water. In essence, the inner foam layer 10, being less
resilient that the outer foam
layers 12, acts as a box spring where there is give and firmness at the same
time. While the
material having a density of 1.7 pounds per cubic foot has been found to be a
preferred density for
the inner foam layer 10, other foams having different densities can be used
with the present
invention and generally include densities that may be within the range of
about 1.0 to about 3.0
pounds per cubic foot.
The outer layers 12 are each comprised of the same material and thickness and
therefore
provides the advantage that the caregiver can position the mattress of the
present invention with
either side facing upwardly and be assured that the conditions and flexibility
of the mattress are the
same for the infant in either orientation.
One foam material that has been found applicable for the outer foam layers 12
is North
Carolina Foam Convoluted AVE3010, having a density of 3.0 +/- 0.20 pounds per
cubic foot and a
resilience (% rebound) of 8-16. The thickness of the outer foam layers 12 for
an infant mattress can
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be about 0.5 inches with a range of 0.25 to 0.75 inches applicable, however,
as stated, the actual
dimensions would depend on the particular application for the mattress. Again,
the material herein
described as usable for the outer foam layer 12 is a visco-elastic foam, and
may be urethane, having
a specific gravity of 0.01 S - 0.08 and be insoluble in water. While the
material having a density of
3.0 pounds per cubic foot has been found to be a preferred density, other
foams having different
densities can be used with the present invention and generally within the
range of about 1.0 to about
5.0 pounds per cubic foot.
As can also be seen in Fig. 1, there are a series or plurality of micro-
convolutes 14 formed
on the interior surfaces 16 of each of the outer foam layers 12. The micro-
convolutes 14 can be
conical in shape and taper inwardly in the direction of the inner foam layer
10 and act as tiny springs
that allow the infant's weight to be dispersed more evenly over the surface on
which the infant is
positioned. Also, by facing the micro-convolutes inwardly toward the inner
foam layer 10, the
exterior surfaces 18 of the outer foam layers 12 are smooth to the infant.
Alternatively, the use of
micro-convolutes can be eliminated such that the interior surfaces 16 of the
outer foam layers may
be flat, relatively planar surfaces.
Turning now to Fig. 2, taken along with Fig. 1, there is shown a top view
illustrating an
outer foam layer 12 enclosing an inner foam layer 10. There can be seen in
Fig. 2, an adhesive
stripe 20 that is placed on the interior surface 16 of the outer foam layer
12, or alternatively, on the
exterior surface 17 of the inner foam layer 10 and the adhesive stripe 20
surrounds the peripheral
edge or perimeter of the outer foam layer 12. In Fig. 2, the adhesive stripe
20 surrounds the entire
perimeter of the outer foam layer 12, however, it is understood that the
adhesive stripe 20 may only
be placed substantially around the perimeter of the outer foam layer 12. In
the embodiment shown
and used for an infant mattress, the adhesive stripe 18 is preferably from
about 0.25 inches to about
2.5 inches in width and, more preferably, about 1 inch in width and can be
sprayed on to the
appropriate surface or applied by other means.
By the use of an adhesive stripe 18 that extends around the perimeter of the
outer foam
layers 12, or inner form layer 10, the interior surface 16 of the outer foam
layer 12 and the
corresponding interior facing surface of the inner foam layer 10 are free from
any adhesive and,
therefore, there is movement that is allowed between the inner and outer foam
layers 10, 12
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inwardly of the adhesive stripe 20. As such, the interior portions 21 of the
foam layers have no
adhesive, thereby allowing the foam layers to react to the weight load of the
infant being exerted
thereon without being bound by any other mechanical means except for surface
contact friction.
The use of an adhesive stripe is to mechanically retain the outer foam layers
12 to the inner
foam layer 10 however other means may be used to mechanicaly retain the foam
layers together
such as stitching, Velcro fastening system or other mechanical means. In a
further embodiment,
there may be no mechanical retaining means between the outer layers and the
inner layer.
Turning briefly to Fig. 3, there is shown a side view of the completed
assembly of the
composite foam structure comprising the three foam layers made up of the inner
foam layer 10 and
the two outer foam layers 12 sandwiching the inner foam layer 10 therebetween.
Turning now to Fig. 4, there is shown a perspective view of the present infant
mattress
illustrating the outer cover 22 that encloses the three foam layers shown in
Fig 3. As explained, the
outer cover 22 is intended to enclose the composite foam structure made up of
the three foam layers
of Fig. 3 in forming the eventual mattress. One suitable material for the
outer cover 22 is Dartex
P091 Polyamide fabric (polyurethane transfer coating on a weft knitted fabric)
and is chosen for its
properties of being washable, dry cleanable, and is capable of being HF
welded. Other comparable
material can, of course, be used for the outer cover 22. The material for the
outer cover 22 should
also be non-toxic and anti-microbial so as to be safe for the contact with an
infant and therefore be
skin friendly or irritation free and can be coated with an anti-fungal and
antibacterial coating.
In the application surrounding the foam layers 10, 12, i.e. the composite foam
structure, it is
also preferred that the outer cover 22 be a loose fit surrounding those foam
layers, that is, the outer
cover 22 should be fabricated and dimensioned so that the outer cover 22 is
not tight around the
inner and outer foam layers 10, 12 enclosed therein. As such, the dimensions
of the outer cover 22
are such that there is a sufficient space surrounding the outer perimeter of
the foam layers 10, 12
such that the outer cover 22 is not taut on the surface and act like a hammock
when the infant is
placed on the mattress. The looseness of the outer cover 22 allows the foam
layers 10, 12 to
perform the function of weight distribution and elimination of pressure points
without the outer
cover 22 causing any considerable effect on the intended performance.
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As one way of assuring such looseness, the outer cover 22 should be
sufficiently loosely
fitted over the foam layers 10, 12 such that when the infant is placed on the
mattress, the normal
expansion of the perimeter dimensions of the foam layers 10, 12 due to the
depression created by
the weight of the infant will not be constrained by the outer cover 22 such
normal perimeter
expansion of the foam layers 10, 12 can readily take place.
The outer cover 22 can be closed about the foam layers 10,12 by means such as
stitches that
surround the mattress as shown in Fig. 4 or there may be an opening 24 in the
outer cover 22 to
enable the foam layers 10, 12 to be readily inserted into and removed from the
outer over 22. The
opening 24 may be secured by means such as a zipper, a Velcro closure system
or other similar
means.
Accordingly, as now constructed, the present mattress is comprised of an inner
foam layer
comprised of a open or closed cell foam material and a pair of outer foam
layers 12 comprised of
a visco-elastic foam material having less stiffness than the inner foam layer
10 and the composite
foam layers 10, 12 are encased in a outer cover 22 of a particular material to
achieve the advantages
of the present invention.
While the present invention has been set forth in terms of a specific
embodiment or
embodiments, it will be understood that the present infant mattress and method
of making the same
herein disclosed may be modified or altered by those skilled in the art to
other configurations.
Accordingly, the invention is to be broadly construed and limited only by the
scope and spirit of the
claims appended hereto.
