Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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RESILIENT GRID FOR USE WITH CELLULAR CUSHIONS
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of provisional application Serial No.
61/359,990, filed June 30, 2010, which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates in general to inflatable cellular cushions and
mattresses and, more particularly, to a resilient grid for use with an
inflatable
cellular cushion that facilitates proper positioning of an individual on the
cushion,
improves seating stability and positioning, protects against bottoming out and
promotes air circulation around the cushion cells. The grid improves cooling
and
reduces moisture retention between the cushion and the user positioned on
same.
Those individuals who are confined to wheelchairs or beds run the risk of
tissue breakdown and the development of pressure sores which are extremely
dangerous and difficult to treat and cure. Heat and humidity are additional
risk
factors for skin break down. Inflatable cellular cushions or mattresses
provide the
most uniform distribution of weight and thus provide the greatest protection
from
the occurrence of pressure sores. These cushions or mattresses generally
comprise a base with an array of closely spaced air cells that project
upwardly
from a common base. The inflatable air cells are generally arranged in
longitudinal and transverse rows, with a predetermined space or interstices
between the cells. Each air cell exerts essentially the same restoring force
against the user's body. In a sense the typical cellular cushion or mattress
provides a highly displaceable surface that tends to float the user. The
inflatable
air cells can be interconnected and/or arranged in inflation zones.
In use, a cushion, for example, is placed on a support surface, such as a
wheelchair seat or the like. The cushion is inflated and the user is seated on
the
cushion. The cushion is slowly deflated to allow the seated user's buttocks to
sink into the cushion until the buttocks are about an inch or so above the
base of
the cushion. The inflation valve is closed. This position should provide an
optimum uniform pressure on the tissue of the buttocks. Often this positioning
is
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done by feel. In some situations if the individual user or care giver is not
properly
trained, the user is not optimally seated on the cushion. Too much or too
little air
is released.
In some situations the inflated cells along the periphery of the cushion
flail,
which decreases stability of the seated user and impairs the effectiveness of
the
cushion in that area of the user's anatomy. Also, in rare situations a cushion
can
deflate, for example, due to a puncture, faulty valve or other reason. Once
the
cushion, or a section thereof, deflates, the user "bottoms out", with the
buttocks
or other part of the anatomy coming to rest on a support surface. Such a
bottoming out situation could result in tissue damage or pressure sores.
Although the cellular cushions or mattresses work well for their intended
purposes, it would be advantageous to provide a means for stabilizing the
inflatable air cell cushion, to facilitate positioning of a user on the
cushion and to
provide some means for lessening the deleterious effects of "bottoming out."
It also would be advantageous to reduce the temperature and humidity or
moisture at the cushion/skin interface to prevent breakdown of the skin.
SUMMARY OF THE INVENTION
One aspect of the invention is a resilient grid for use with a cellular
cushion
or mattress, the grid comprises a plurality of structural members that define
a
plurality of openings, for example, like a latticework, each opening
dimensioned
to fit around a cell of a multi-cellular cushion, mattress or mattress overlay
when
the grid is positioned on the base of the cushion or mattress. When the grid
is in
place, each cell of a cellular cushion or mattress product protrudes through
an
opening of the grid. The cross members of the grid occupy the interstices
between the cells to facilitate air flow among the cells. With grids
constructed of
certain materials movement of a user on the cushion and grid may cause the
resilient grid to either compress to expel air or expand to draw in air, i.e,
breathe,
thereby further enhancing air flow among the cells for cooling and drying.
In another aspect of the invention the grid facilitates initial set-up and
adjustment of the user on the mattress or cushion. For example, the cushion is
inflated and the user is positioned on the cushion. The air in the air cells
is
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adjusted until the user is immersed into the cells until positioned just above
the
resilient grid.
In another aspect of the invention the resilient grid positioned on the base
of the cushion or mattress provides additional protection against bottoming
out in
the event the inflatable cushion or mattress leaks air. The user comes to rest
against the resilient grid rather than a harder support surface such as a
chair
seat, conventional mattress or the like.
Further, the resilient grid provides stability to the cells that are
positioned
in the grid and prevents cells, particularly on or around the peripheral edges
of
the cushion or mattress, from flailing or moving in use.
In another aspect of the invention the grid comprises support sections for
positioning under select areas of the user's anatomy, and bolsters along the
edges of the grid to provide stability and positioning.
In another aspect, the grid is provided in modular units.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of one aspect of a support grid of the present
invention;
FIG. 2 is a top plan view of an aspect of the support grid of the present
invention
positioned on an inflatable cellular cushion;
FIG. 3 is a rear perspective view of an aspect of a support grid;
FIG. 4 is rear elevational view of a support grid;
FIG. 5 is an exploded view of an aspect of a support grid;
FIG. 6 is a rear perspective view of an inflatable cellular cushion with a
front
element of a support grid of the present invention;
FIG. 7 is a side elevational view of a cushion with one aspect of a support
grid of
the present invention; and
FIG. 8 is a side elevational view of a cushion with the support grid with a
side
bolster removed.
DETAILED DESCRIPTION
One aspect of a support grid of the present invention is indicated by
reference number 10 in the drawings. The grid is intended to be used with a
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support cushion or mattress that has a base with an array of independent,
upstanding cells across the base.
Grid 10 is constructed from a resilient material, for example, polyurethane
foam or similar material. The foam can be closed cell or open cell. Other
types of
materials can be employed such as three dimensional knit spacer fabric where
opposing monofilaments are vertically aligned to form a vertical support
structure.
The choice of material for the grid is based upon the support or air flow
characteristics desired in any given grid.
Grid 10 includes a body 12 that comprising a plurality of structural members
13. The structural members may be arranged in transverse and longitudinal
rows, as seen in the drawings and may be referred to as cross members.
Although the width of the cross members may vary, in one aspect structural
members 13 are approximately 1/4 inch to 3/8 inch wide. In any event, the
width of
the cross members can be any width depending upon the size of the space
between the cells of an inflatable air cell cushion, as will be explained.
Similarly, the height of the elements of the grid structural members can vary
depending upon the material used to form the grid and the support
characteristics
desired. In one preferred aspect of the invention the grid is approximately
1/4 inch
to 1 inch in height, more preferably about 1/2 inch to 3/4 inch in height.
However,
any height that meets the desired functional characteristics of the grid is
encompassed by the scope of the invention. Moreover, sections of grid may be
stacked to achieve desired support characteristics.
Grid 10 also comprises margins 14 which, in one embodiment, are 3/4 inch in
width. However, the margins can be any width and, in certain aspects to be
described below, the margins comprise bolsters or the like. In some
embodiments, the grid does not have peripheral margins.
The grid may be sized and configured to encompass all of the upstanding
cells on a cushion or may be sized appropriately relative to the cellular
cushion
on which it is placed so that it only occupies a desired area of the cushion,
for
example, only the seated user's ischial area or the area under the thighs.
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In the illustrated embodiment, the cross members extend both transversely
and longitudinal to define individual openings 15 and form an array of
openings
which can be referred to as a grid. It will be noted that, as shown, openings
15
are rectangular and arranged in longitudinal and transverse rows. The
arrangement of openings 15 can be any arrangement desired so as to be
complementary to the array of cells on the cellular cushion with which it is
employed. The openings can be staggered or grouped or of different sizes
within
the same grid.
The structural members 13 do not have to be linear. For example, the grid
may employ structural members that are circular, for example, defining
openings
15 that are circular in cross section. Moreover, the structural members can be
oriented to form openings having other configurations such as triangular,
ovals,
star shapes and so forth.
Also, the number of openings 15 in any individual grid will be determined by
the cellular cushion with which it is used, or the area of a cushion on which
it will
be used. The size of openings 15 may also vary as required. For example, in
one aspect of the invention, openings 15 are 1 3/8 inch by 1 3/8 inch square.
However, they can be any size or configuration required for its intended
purpose.
In one aspect of the invention, grid 10 is intended for use on a cellular
cushion, preferably on an inflatable air cell cushion 16. Although one
illustrative
use is with an inflatable air cell cushion, grid 10 may be employed with any
cushion having an array of individual upstanding cells. And, although the
detailed
description refers generally to cushions for purposes of brevity and clarity,
it will
be understood that the same principles apply to use with cellular mattresses
and
mattress overlays.
In any event, as illustrated cushion 16 includes a base 18 and a plurality of
individual upstanding, cells, in this case inflatable air cells 20, arranged
in
longitudinal and transverse rows across base 18. One preferred inflatable
cellular cushion and a method of making it is described in U.S. Patent No.
4,541,136, which is incorporated herein by reference. There are interstices 21
between the cells. The cells can be isolated or interconnected through the
base
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or can be divided into individual inflation zones, as shown and described, or
example, in U.S. Patent No. 6,697,936, which also is incorporated herein by
reference.
Cells 20 can have any cross-sectional configuration. For example, they can
be finned, rectangular or any desired shape. The cross-sectional configuration
of
the cell, particularly at the cell base, generally is complementary to the
configuration of opening 15 as defined by the structural members.
Although the illustrated embodiment shows cushion 16 having a generally
rectangular configuration with longitudinal and transverse rows of upstanding
inflatable cells, the grid of the present invention may be used with any
configuration of inflatable air cell cushion or mattress and the construction
and
inflation characteristics of cushion 16 are incidental to the invention. For
example, grid 10 could be used with a cellular cushion having a generally
saddle-
shaped configuration for use on a motorcycle seat or a substantial circular
configuration for use with a stool or other seat. A grid employed on cushions
of
other configurations only would require that the openings 15 be complementary
in
configuration to the upstanding cells of the cushion.
As illustrated, body 12 of grid 10 is positioned on base 18 of the cushion.
Each individual inflatable cell 20 is positioned within an opening 15 and the
cross
members 13 surround the exterior of the cell, generally adjacent the base of
the
cell, creating air flow paths 22 between the cells. The cross members 13 of
grid
fit around the bottom or base of the inflatable cell such that the upper
portion
of the inflated cell can expand and form a contiguous support surface. Cross
members 13 preserve the integrity of interstices 21 when the cells are
inflated
creating patent air flow paths and thereby enhancing airflow between the
cells.
In use, cushion 16 is placed on a support surface, such as a wheelchair
seat with grid 10 positioned on a cushion as explained. Grid 10 may extend
over
the entire expanse of cushion 16 or may be positioned only on selected areas
of
the cushion, as explained above. The inflatable cells 20 then are inflated
through
a valve as understood in the art. The user is positioned on the cushion and
air is
released from the cells until the user's body, for example the buttocks and
ischial
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area, are properly immersed in the cellular cushion and positioned just above
grid
10. The valve is closed to secure the cells in their desired inflated
condition. If the
cushion 16 is a zoned cellular cushion, the user is positioned on the cushion
and
it is adjusted as disclosed in U.S. Patent No. 6,687,936, which is
incorporated
herein by reference.
In one aspect of the invention, grid 10 can help prevent bottoming-out if
the inflatable cellular cushion loses air. The seated user would only sink
down
until his buttocks came to rest on the resilient grid and hence would not come
to
rest on a hard support surface that could cause pressure sores or other harm.
Hence, the grid can be constructed from an appropriate resilient, yet
supportive
material that can provide adequate support to a seated user if the air cell
cushion
bottoms out help prevent the formation of pressure sores, particularly if the
bottoming out is temporary or limited in time.
As stated above, in another aspect of the invention, cross members 13
maintain the integrity or patency of the interstices between the cells, which
allows
more air flow among the cells for cooling and prevent fluid retention.
Moreover, depending upon the material the grid may be compressed and
released by movements of the seated user. This alternating compression and
release can increase air flow between the cells by a breathing or bellows
action
to help cool the areas between the i cells and hence cool the user's buttocks
and
ischial area.
The presence of grid 10 provides for optimum positioning. In cushions
without the novel grid, the cushion is placed on a support surface and the
user is
seated on a cushion, the cushion is inflated. Air is released from the cushion
until
the user is immersed in the cushion to the optimum depth, generally an inch or
so
above the support surface. With grid 10 in place, the cushion can be deflated
until
the user's buttocks are positioned right at the surface of the grid, thereby
assuring correct positioning and immersion.
Furthermore, in one aspect of the invention, grid 10 improves stability of
the seated user. With cross members 13 surrounding the base of an individual
cell, each cell seated in an opening 15 is stabilized to prevent shifting for
flailing,
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particularly cells on the edges of the cushion. Moreover, relatively small
grids
that fit over only the cells along the edges of the cushions may be employed
to
prevent flailing of the cells. A smaller grid could be placed under the thigh
of a
person who had a leg amputated to offset loading and position the seated user
more symmetrically. Furthermore, sections of grid may be stacked to vary the
support characteristics.
It will be noted that although grid 10 can be a simple, flat rectangular grid,
it also can be constructed with other elements to enhance seating stability.
As
seen in FIGS. 3 through 8, one aspect of grid 10 includes a front support 23.
Support 23 includes downwardly angled side wall 24 at the margins 14 that
extend toward the rear of the grid and cushion. Front support 23 could include
troughs for proper positioning of the user's thighs. Side walls 24 can
function as
bolsters to better position the seated user and provide lateral stability.
They can
be of any desired height to provide optimum lateral support.
Furthermore, various elements of a grid may include a first side bolster 26
on one side of the main body and a second side bolster 28 on the opposite side
of the main body. The bolsters 26, 28 angle forward and ramp up the downwardly
angled wall 24 of front support 23. Front support 23 provides a contoured or
rearward angled, raised seating surface for better positioning. Each of the
components includes cross members 13 which define openings 15 that fit around
cells of the cellular cushion. Grid 10 with bolsters and supports can be a
unitary
apparatus or provided as modular units with several elements or components.
Each of the elements can be constructed of a material that provides for
optimal
support characteristics. They can be harder or softer. They can be provided as
modular elements of varying height. Moreover, they can be stacked to provide
customized support.
It will be understood that various changes and modifications may be made in
the illustrated embodiments without departing from the scope of the invention.
Hence, the description and drawings are intended to be illustrative only and
should not be viewed in a limiting sense.
