U.S. patent application number 11/707378 was filed with the patent office on 2008-08-28 for shape matching cushion.
Invention is credited to Robert H. Graebe.
Application Number | 20080201853 11/707378 |
Document ID | / |
Family ID | 39690728 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080201853 |
Kind Code |
A1 |
Graebe; Robert H. |
August 28, 2008 |
Shape matching cushion
Abstract
A cushion comprising an array of individual suspension elements
arranged in a pattern wherein one embodiment the longitudinal axis
of each suspension element in the array is positioned at a right
angle or parallel to the longitudinal axes of the adjacent
suspension elements. Each suspension element has a displaceable
load-bearing surface, a first end wall, a second end wall, and an
optional bottom wall, with load-bearing surface and recited walls
defining an inner chamber. The material thickness of the
load-bearing surface generally is greater than the material
thickness of the end walls whereby the end walls deflect outwardly
toward the load-bearing surfaces of adjacent support elements under
load. The load-bearing surface can have a substantially
arch-shaped, elliptical or rectangular cross-section and may be
constructed from different materials to make a composite suspension
element. The bottom wall of the suspension element may have a small
vent opening of a predetermined size to allow a controlled release
of air from the inner chamber under load to enhance the viscous
feel of the cushion. The cushion also includes a cover enclosing
the array of suspension elements.
Inventors: |
Graebe; Robert H.; (Fort
Lauderdale, FL) |
Correspondence
Address: |
POLSTER, LIEDER, WOODRUFF & LUCCHESI
12412 POWERSCOURT DRIVE SUITE 200
ST. LOUIS
MO
63131-3615
US
|
Family ID: |
39690728 |
Appl. No.: |
11/707378 |
Filed: |
February 16, 2007 |
Current U.S.
Class: |
5/653 ; 5/655.9;
5/953 |
Current CPC
Class: |
A47C 27/144 20130101;
A47C 27/146 20130101; A47C 27/148 20130101; A47C 27/15
20130101 |
Class at
Publication: |
5/653 ; 5/655.9;
5/953 |
International
Class: |
A47C 27/14 20060101
A47C027/14 |
Claims
1.-20. (canceled)
21. A cushion comprising: an array of individual molded foam
suspension elements arranged in a pattern wherein a longitudinal
axis of each suspension element in the array is positioned at a
right angle to the longitudinal axes of the adjacent suspension
elements; each said suspension element having a displaceable
load-bearing surface having a substantially arch-shaped
cross-sectional configuration, a first end wall, a second end wall,
and a bottom wall, said load-bearing surface and said recited walls
defining an inner chamber, wherein the material thickness of the
load-bearing surface is greater than the material thickness of the
recited end walls whereby said ends walls distend outwardly when
force is applied to said load-bearing surface; and each said bottom
wall having an opening formed therein of a predetermined size to
allow a controlled release of air from the inner chamber when force
is applied to said load bearing surface.
22. The cushion of claim 21 further comprising a cover around the
array of individual molded foam suspension elements.
23. The cushion of claim 21 wherein the array of individual molded
foam suspension elements is molded from polyurethane foam having a
polyurethane film outer layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable
BACKGROUND OF THE INVENTION
[0002] The invention relates generally to support surfaces that
facilitate blood flow and prevent tissue breakdown and more
particularly to a molded foam cushion having suspension elements
that are shaped and positioned to form a shape matching support
surface that has relatively uniform restoring forces when deformed
under loads from of a user.
[0003] Individuals confined to bed or to a wheelchair run the risk
of tissue breakdown and the development of ischemic induced sores,
which are extremely dangerous and difficult to treat and cure. For
example, when seated much of the individual's weight concentrates
in the region of the ischia, that is, at the bony prominence of the
buttocks, and unless frequent movement occurs, the flow of blood to
the skin tissue in these regions decreases to the point that the
tissue breaks down. When lying down, the hip region may protrude
deeper into the mattress than the adjoining waist or thigh regions
and as a consequence the supporting forces exerted by the mattress
would be greater at the hips than at the thighs or waist, for
example. Any skin area where there are sustained deformation
experiences reduced blood flow and the skin does not receive
sufficient oxygen and nutrients.
[0004] It is desirable to have a support cushion or mattress which
applies generally uniform supporting forces, that is, a generally
uniform counter force on the tissue of the user positioned on the
cushion or mattress. When a cushioning structure is deformed while
supporting a person it is desirable to have a constant restoring
force that exerts equal forces over a broader area of the body
minimizing deformation of the soft tissues and help prevent skin
and tissue breakdown by facilitating blood flow in the contacted
area.
SUMMARY OF THE INVENTION
[0005] One aspect of the invention provides for a cushion having an
array of suspension elements. Each suspension element has a
displaceable, load-bearing surface, a first end wall, a second end
wall, and an optional bottom wall. The load bearing surface, end
walls and bottom wall, if present, define an inner chamber. The
material thickness of the load-bearing surface is greater than the
material thickness of the end walls so that the end walls can
distend outwardly when force is applied to said load-bearing
surface. The optional bottom wall has a vent opening formed therein
of a predetermined size that allows controlled release of air from
the chamber when force is applied to the load bearing surface to
control collapsing of the cell.
[0006] The surface of the cushion is displaceable that, when
deformed, exerts a restoring force that is generally constant
irrespective of the extent of the deformation. The cushion applies
a generally uniform supporting pressure against an irregularly
contoured body supported on the cushion.
[0007] In one aspect of the invention the array of suspension
elements is arranged in a pattern wherein the longitudinal axis of
each suspension element is positioned at a right angle relationship
to the longitudinal axis of the adjacent suspension elements. The
right angle axis position of the suspension elements improves
stability imparted to the user.
[0008] In another aspect of the invention the axes if adjacent
suspension elements are aligned to maintain shape-fitting
performance.
[0009] In one aspect of the invention the load-bearing surface has
a generally arch-like cross-sectional configuration to facilitate a
controlled buckling function. In other aspects of the invention the
load-bearing surface has a substantially elliptical cross-sectional
configuration or a substantially rectangular cross-sectional
configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view of one embodiment of a cushion
of the present invention with a cover partially cut away;
[0011] FIG. 2 is a bottom perspective view of the cushion of FIG. 1
without a base and with the openings into the suspension elements
exposed;
[0012] FIG. 3 is a partial bottom plan view of a cushion of the
present invention with the base intact;
[0013] FIG. 4 is a cross-sectional view of a suspension element of
the present invention;
[0014] FIG. 5 is a representational cross-sectional view of a
partial row of suspension elements from a cushion of FIG. 1;
[0015] FIG. 6. is a representational cross-sectional view of a
partial row of suspension elements having an alternative
configuration;
[0016] FIG. 7. is a representational cross-sectional view of a
partial row of suspension elements having another alternative
configuration;
[0017] FIG. 8 is a representational cross-sectional view of a
partial row of suspension elements of FIG. 4 under load;
[0018] FIG. 9 is a perspective view of another embodiment of a
cushion of the present invention with a cover partially cut away;
and
[0019] FIG. 10 is a perspective view of another embodiment of a
cushion of the present invention with a cover partially cut
away.
DESCRIPTION OF THE INVENTION
[0020] In general, the present invention provides for a cushion
having an array of hollow suspension elements that create a
displaceable constant restoring force, shape-matching surface. The
suspension elements include a load-bearing surface, end walls, and
an optional bottom wall or membrane that closes off the hollow
suspension element. Each bottom wall, when present, has an optional
vent of a predetermined size formed therein to allow venting of air
from the hollow suspension element when force is exerted on the
support surface. The base of each suspension element generally has
rectangular configuration permitting a high density of suspension
elements per area or cushion for more contact area to the supported
person. The array of suspension elements is arranged in a pattern
across the expanse of the cushion wherein the longitudinal axis of
each suspension element is positioned at a right angle relationship
to the longitudinal axis of the adjacent suspension elements. This
results in greater longitudinal stability and effective surface
area at the anatomical contact site.
[0021] The array of suspension elements creates a cushion that when
engaged matches the shape of an object placed thereon with nearly
uniform, predetermined counter forces. The size of the vent in the
suspension element base wall, or located in a film used to seal the
bottom of the suspension element controls the rate of air flow out
of the suspension element and hence allows for damping control of
the counter force exerted by the suspension element. The employment
of equal counter forces while matching the shape of a person is
beneficial in facilitating blood flow in those tissues that are
under load. The primary benefit is in minimizing deformation of the
vascular network, which provides blood flow to those local tissue
cells.
[0022] It will be appreciated by those skilled in the art that the
suspension elements of the present invention provide a plurality of
ways by which the collapse or deformation of the elements and the
constant restoring force may be controlled or adjusted. For
example, arrangement or position wall thickness, material
selection, cross-sectional configuration, the presence or absence
of a bottom wall, the size of the opening in the bottom wall, if
present, provide for optimal control of the deflection
characteristics and constant restoring forces of the array of
suspension elements comprising a cushion
[0023] It will be appreciated that while reference is made
primarily to cushions, the same inventive principles are applied to
mattresses and or any other support surface for the proper support
and positioning of a user. Hence the term cushion as used in herein
and in the appended claims is intended to encompass conventional
cushions, wheelchair cushions, mattresses, mattress overlays, heel
pads, insoles, chair backs and any other anatomical support
structure.
[0024] FIGS. 1 through 5 illustrate one representative embodiment
of a cushion of the present invention, indicated generally by
reference numeral 10. Cushion 10 includes an array of individual
suspension elements 12. As seen in FIGS. 4 and 5, the suspension
elements 12 have a load-bearing surface 14. The load-bearing 14
surface, in its normal state, has opposed vertical sides 16 and 18
and a top surface 19. The material thickness of the load bearing
surface is greatest at the top surface and the thickness decreases
or tapers toward the base. That is, the wall thickness of the arch
shape becomes less thick. This taper generally occurs when the
outside curve of the arch is greater or a different curve, i.e.,
elliptical, curve from the inside arch. Having a taper will
influence the buckling function, which helps to create a constant
restoring force, during the range of deflection, as will be
described below. The material thickness of the load bearing
surface, the taper or both may be adjusted to so as to obtain an
optimal buckling or deformation characteristics for any given
application.
[0025] The suspension element 12 also a first end wall 20 and
second end wall 22. The suspension elements are hollow and the
load-bearing surface and end walls define an opening 24 and an
inner chamber 26. Also, it will be appreciated that the
configuration of each opening 24 of each suspension element is
rectangular, which allows for the adjacent placement of multiple
suspension elements, side-by-side in rows across the expanse of
cushion 10.
[0026] As seen in FIG. 4, the cushion can comprise a composite
material wherein the suspension elements 12 are constructed from a
molded foam F and the outer surface is a thin polyurethane layer P
that creates a smooth, moisture impervious surface. Alternatively,
the foam layer F may be covered by a layer P of neoprene or other
rubber. Foam material works well and reduces the overall weight of
the cushion. In other embodiments, the entire suspension element
may be molded from neoprene, with a skin of neoprene to seal the
outer surface. Again, the choice of material, i.e. foam, foam and
polyurethane composite, neoprene or so forth can be used to obtain
desirable deflection or deformation and constant force restoring
characteristics.
[0027] FIG. 3 illustrates the bottom of one embodiment of a cushion
10 which includes a substantially flat base 28 which forms a base
or bottom wall 30 for each of the individual support elements 12.
It will be appreciated that base 28 can be a continuous web of
flexible material, such as polyurethane film P or other
membrane-type material, and is adhered to the bottoms of the
suspension elements and around opening 24, as at sealed areas 29,
so that chamber 26 is enclosed and each suspension element is
isolated and discrete and the inner chambers 26 of the suspension
elements are not in fluid communication with those of the adjoining
suspension elements. The enclosed suspension element is more
sanitary than an open structure and more durable. The cushion may
be constructed from an array of support elements that have no base
or bottom wall and are open on the bottom
[0028] As seen in FIG. 3, there may be a hole or vent 32 formed in
each bottom wall 30. Although shown positioned substantially in the
center of bottom wall 30, the vent may be place anywhere in the
bottom wall as long as the vent 32 is in fluid communication with
chamber 26. It will be appreciated that the diameter of vent 32 is
predetermined so that there is a predetermined rate of airflow out
of the chamber of each suspension element, as will be described in
more detail below. Positioning of the vent 32 in bottom wall 30
also may affect the rate of airflow out of the suspension elements.
The vent 32 controls the rate of expelling the air trapped inside
chamber 26 of suspension element 12 and imparts a higher viscosity
feel to the cushion than could be provided by mechanical means
alone. Of course, the suspension elements may have bottom wall 30
that has no hole or vent. Or, a cushion could employ some
suspension elements with vents and some without, depending upon the
desired effect. Moreover, employment of a bottom wall or no bottom
wall is another factor that allows control of the collapsing
characteristics of the individual support elements 12.
[0029] In any event, the size of vent 32, if one is present, is
determined by the dimensions of the suspension element and the
volume of chamber 26 so as to impart the desired viscous feel to
the cushion as the user is positioned on the cushion. In one
representative embodiment, the suspension elements are
approximately 13/4.sup.th inches long, approximately 11/2 inches
wide and approximately 11/2 inches in height. In this
representative embodiment a vent hole of sufficient diameter is
used to impart a desired feel through the controlled expulsion of
air during seating. Of course, the suspension elements can be of
any desired dimensions. The size of the vent 32 can vary to achieve
desired support characteristics.
[0030] In one aspect of the invention the longitudinal axis x of
one suspension element 12 is positioned at a right angle to the
longitudinal axis y of the adjacent support element as seen in
FIGS. 1 and 3. As best seen in FIG. 5, the end walls 20 and 22 of a
suspension element are directed toward the sides 16 and 18 of the
load-bearing surfaces 14 of the adjacent suspension elements
12.
[0031] Those suspension elements having longitudinal axis x are
arranged in a plurality of rows with the axes of the suspension
elements in any given row being in rectilinear alignment. Those
suspension elements with longitudinal axis y are arranged in a
plurality of rows with the axes of the suspension elements in any
given row being in rectilinear alignment. Placing each suspension
element at right angles to the adjacent suspension elements
promotes lateral stability of the individual suspension elements
and enhances motion stability for the user positioned on the
cushion, as will be discussed below. The cushion can have any
number of rows of suspension elements, depending upon the desired
size of the cushion.
[0032] In the embodiment of FIGS. 1 through 5, the load-bearing
surface 14 of each suspension element 12 has an arcuate top surface
19 creating a suspension element 12 having a substantially
arch-shaped cross-sectional configuration. The cross-sectional
configuration of the support elements affects the compression or
deformation characteristics of the suspension element 12 when
downward force is applied. For example, when a user is seated on
cushion 10, the load or downward force on the support elements will
cause the suspension elements to partially compress or deform. Also
as seen in FIG. 5, the substantially uniform cross-sectional
material thickness of load-bearing surface 14 is greater than the
material thickness of the end walls 20 and 22. Control or
modification of the relative material thicknesses of the
load-bearing surface to the material thickness of the end walls can
be used to achieve desirable deformation and restoring force
characteristics.
[0033] As shown in FIG. 7, the load bearing surface 14 is
displaceable and vertical sides 16 and 18 may deform and bow
outwardly as force is applied to the cushion, for example by a
user's body B positioned on the cushion. The air entrapped in
chamber 26 is released slowly through vents 32 and, therefore, the
remaining air is compressed and causes end walls 20 and 22 to
deform and actually to distend outwardly toward to the adjacent
support elements 12. This deformation or bowing of the support
surface and distension of end walls 20 and 22 is referred to as the
deflection travel of the suspension element 12.
[0034] Under load, the end walls 20 and 22 abut sides 16 and 18 of
the load bearing surface 14 of the adjacent suspension element so
that the deformed or deflected suspension elements 12 form a
substantially uniform support surface that conforms to the shape of
the user's body B. The end walls 20 and 22 provide stability in the
deflection travel of the suspension element 12 under load. That is,
the cushion will feel more stable to a positioned user due to the
reduced deflection travel. Moreover, the restorative force of the
deformed suspension elements 12 is nearly constant throughout its
deflection travel. the cushion* assumes the shape while exerting a
uniform support force on the body B positioned on the cushion to
minimize deforming soft tissues which facilitates blood flow.
[0035] As seen in FIGS. 1 and 2, the entire cushion can be enclosed
in a cover 34. The cover cooperates with the support elements 12 to
provide a generally uniform support surface. The cover can have a
top panel 36 and side panels 38 made from a stretchy material, such
as a stretchy nylon or spandex and a bottom panel 39 made of a
tacky or rubberized material or other material having a higher
coefficient of friction than the support surface on which the
cushion is placed to keep the from sliding. One such cushion cover
is disclosed in the inventor's U.S. Pat. No. 5,111,544, which is
incorporated herein by reference. Of course, any type of cover that
functions appropriately is intended to be within the scope of the
invention.
[0036] The suspension elements 12 generally are molded in sheets
from high density foam using a two-piece mold having a female and
matching or different male shape with clearance for developing a
suitable wall thickness and shape. Molding the product permits
using multiple layers of different materials by using the female
side of the mold to first vacuum form a plastic film or form a
rubber film by dipping to serve as the top and side that the user
would engage. The mold then is filled with foam material. The male
side of the mold is inserted. The foam is allowed to cure. The foam
can be injection molded if a closed mold is used. The cushion can
comprise a combination of a polyurethane outer film with an inner
shell of polyethylene or polyurethane foam to produce a more
durable structure with improved moisture and abrasion resistance
and flex life. The polyurethane film or membrane can form the base
28 of the cushion and, of course, the bottom walls 30 of the
suspension elements.
[0037] FIGS. 5 and 6 illustrate alternative aspects of suspension
elements of the present invention. As seen in FIG. 5, suspension
elements 12' include a load bearing surface 14', side walls 16' and
18', end walls 20' and 22', and a bottom wall (not shown) which
define inner chamber 26'. Load bearing surface 14' includes a
rounded top surface 19'. It will be appreciated that a cushion
constructed of suspension elements 12' may include a bottom wall
with a vent, as already explained. Load bearing surface 14' has a
substantially ovoid or elliptical cross-sectional configuration
with side walls 16' and 18' having substantial curvature. It will
be noted that the material thickness of load bearing surface 14' is
greater than the material thickness of end walls 20' and 22'. The
suspension elements 12' are positioned at right angles to each
other as previously discussed.
[0038] FIG. 6 illustrates suspension elements 12'' having load
bearing surface 14'' with a substantially vertical side walls 16''
and 18'' and horizontal, substantially flat top wall 19''.
Consequently, suspension elements 14'' have a substantially
rectangular cross sectional configuration. As with the other
illustrated designs, suspension elements 12'' include end walls
20'' and 22'' that have a material thickness less than the material
thickness of load bearing surface 14''. When employed in a cushion,
suspension elements 12'' could include a vented bottom wall and an
inner chamber 26''. FIGS. 5 and 6 illustrate that representational
embodiments of cushion suspension elements of the present invention
can have any acceptable cross-sectional configuration that allow
the suspension elements to function in accordance with the broader
principles of the invention. Consequently, although three
representational embodiments are shown, the scope of the invention
and the appended claims should not be limited to any preferred or
illustrative embodiments.
[0039] FIGS. 9 and 10 illustrate other representative embodiments
of the present invention. FIG. 9 shows an embodiment of a cushion
100 having an array of suspension elements 120 arranged in rows
with the longitudinal axes of the suspension elements in each row
being in rectilinear alignment . . . FIG. 10 depicts an embodiment
of a cushion 200 having an array of suspension elements 220
arranged in rows with the longitudinal axes of the suspension
elements in each row being in rectilinear alignment. The suspension
elements 120 and 220 are constructed similar to those described
above. However, they are not positioned at right angles.
[0040] Cushion 100 provides for axially aligned suspension elements
120 that are positioned side-to-side with the suspension elements
in adjacent rows of suspension elements. Cushion 200 provides for
axially aligned suspension elements 220 that are off-set or
staggered relative to the suspension elements in adjacent rows of
suspension elements. It will be appreciate by those skilled in the
art that the relative positioning of adjacent support elements can
influence the deformation and constant restoring force
characteristics of the cushions. In the embodiments of FIGS. 9 and
10, those characteristics also can be modified by manipulation of
the choice of materials, the material thickness or taper of the
load bearing wall, the relative material thickness of the end
walls, the use of a bottom wall and the size of the vent in the
bottom wall, if present.
[0041] Moreover, the foregoing written description and accompanying
drawings are intended to be illustrative of the broader aspects of
the invention and the best mode of working the invention presently
known to the inventor and should not be construed as limiting the
scope of the invention as defined by the appended claims.
* * * * *