Note: Descriptions are shown in the official language in which they were submitted.
1322~4
PREFO.OlB PATENT
~NATOMICALLY ~ONFO~NABLE FOA~ S~PPORT PAD
~kqround of the Invention
This invention relates to pads for supporting the
seated and recumbent human body which redistribute body
weight away from bony prominent areas, which areas are the
most susceptible to the formation of pressure ulcers and,
in particular, to aonvoluted ~oam pads used for this
purpose.
Two of the primary causes of pressure ulcers are
pressure and moisture. The pressure results from the
supporting surface resisting the force of gravity on the
body. For mattresses, this pressure i~ typically t~e
hiqhest beneath the 6houlder (the scapulae) and tail (the
sacrum and trochanter), generally the areas of greatest
~5 mass and proiection. In these high pr~ssure areas, the
pressure against the body can be sufficient to occlude the
capillaries and l~mph vessels, thereby preventing the
circulation of oxygen and nutrients to the skin. In
addition, because airflow over these skin areas is
typically prevented due to the ~urface of the mattress,
greater amounts of moisture are excret~d for th~
- dissipation of heat and waste. Qver a ~ufficient period of
time, the combination of high pressure and moisture will
le~d to the formation of pressure ulcers.
25In an ~ffort to combat th~ formation of pressur~
ulcers among patient~, hocpitals utilize a number o~ types
: of bed pads for their patients who fall into high risk
categories. These product~ include ~atic air, water and
~oam ~upport pad~. Although~these pa~s cannot reduce the
overall resistance of ~he ffl~ttress to the wei~ht of the
body,~they~can reduce the level of pressure on the areas of
highest pressur~ by redistributing ~he load ~nd allowing a
: greater portion o~ the pad to ~upport: the body. Each of
these type ~ o~ pads has di~eren~ advantages and
; 35 disad~antages.
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~L322~2~
Generally, 6tatic ~ir and water support pad~ provide
~uperior high pressure reduction capabilities at the bony
prominences, but permi~ only limited air flow and heat
dissipation. In addit$on, both tatic n~r and wa~er
support pads reguir~ filling, are fiusceptible to leaks and
tend to "bottom out" (i.e., permit tha weiqht of the user
to displace the air or water in the pad to the extent that
the u~er is supported by the mattre~s, r~ther than by the
air or water cushion). Static water BUpport pads ~150 are
undesirable in that they ~re heavy and unwieldy to
transport. Nhile pumps ~nd valves can be used to vary the
pressure re~istance of the static air ~nd water pad~ over
time, these features render the pad both ~xpensive and
di~ficult to install and transport.
Convoluted foam pads, on the other hand, are generally
relatively inexpensive and easily transported, while
providing 6uperior ~ir ~low potential ~nd mo$~ture
reduction capabilitie~. Unfor~unately, despite
considerable ~tudy and e~fort, ~t has proved exceedingly
difficult to develop an ~sily manufactured convoluted ~oam
pad which is capable of providing pressure reduction
characteri~tics comparable to ~ta~ic air and wa~er ~upport
pa~s.
The ~anu~cture o~ convolut~d ~oam p~d~ continues to
largely follow the method~ tau~ht by U.S. ~atent ~o.
- 3,431~802. The pads are typically ~ormed by ~eeding a
foam block between two cooperating parallel cylind~r~, each
o~ which has ~ undula~ed ~ur~ace. The cylind~r~ r~ a
towards one another and are ~paced ~o ~ a~ bl~ck
insertéd b~tween them is co~pre~ed between the cylinder6
~nd i~ ~riven ag~inst a cuttin~ ~dge whiah ~lices t~@ block
in hal~ ch hal~ generally compri~e~ ~lte~nat~ng rows
o~ pe~k6 and v~lley~, ~n chec~er~oard fa6~0n. Tbe
re~ulting halve~ ar~ perfectly ~at~hed ~ that when one
h~ id upon the ~ther, the top~ of the peaks of one
~,,
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~L3~42~
half rest against the floor of the valleys of the other
half forming a 601id block. In addition, although it is
possible to manufacture pads which are not the mirror image
or reflection of one another, this is rarely done, as it
would typically result in only one usable half, thereby
significantly increasing material costs.
One convoluted ~oam pad currently in use is disclosed
in U.S. Patent No. 4,686,724. ~he pad is comprises
alternating column~ of peaks and valleys in checkerboard
fashion. Air channels are stamped, press cut or laser cut
through the ~loor of the valley6 to the bottom face of the
pad, lea~ing removable plugs used to selectively control
the amount o~ aeration and dissipation of body heat
permitted by the pad.
In one embodiment, the peaks of the pad are "topped
off" to create a broken flat surface, interposed with
valleys, with the distance between the floor of each valley
and the bottom surface of the pad being constant. Within
each valley is a channel extending from the valley floor to
the flat bottom ~ace of the pad. The patent teaches that a
skin area of 1.25 inches in diameter or lesc~ even though
denied air circulation, can 6ustain it~elf from air
circulating in an adjacent area. Therefore, by limiting
each peak top to a diameter of 1.~5 inch~s or less, the
occurrence o~ decubitus ulcers can, ~ccord$ng to the
patent, be virtually eliminated. Unfortunately, the use of
this uniform pad with its removable plugs has found little
acoeptance in practice, perhaps ~ecause ~he removal ~nd
replacement of the individual plugs is relatively difficult
and time consuming.
A æecond con~oluted foam pad is disclosed in U.S.
Patent No. 4,620,337. The pad i~ designed to prev~nt the
form~tion of decubitus ulcer~ ~y ~inimizing t~ a~oun~ o~
pres6ure exerted on the body. The pad has ~hree distinct
~ections: a convoluted head ~upporting ~ection; a ribbed
torso ~upporting 6ection; and a convol~ted foot and leg
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~322~4
~upporting Lection. As with most foam pads which are
manu~actured from a block of uniform thickness, the sum of
the distance from the bottom face of the pad t~ the top of
any peak (the "peak height") and the di6tance from the
bot~om face of the pad to the floor of any valley (the
"base height" or "valley floor height") remains constant.
This arises from the fact that although the height of the
undulating surface of the paired cylinders varies along
their length, the opposing undulating surfaces are of an
equal height.
The pad is designed on the premi~e that heavier
portions of the body are less likely to develop pressure
ulcers when they are supported by a portion of the pad with
a lower peak to base ratio, and that lighter portions of
the body are less likely to develop pressure ulcers when
they are supported by a portion of the pad with a higher
peak to base ratio. Accordingly, the xibs of the torso
supporting section are shorter than the average height of
the peaks of the head or leg supporting ~ections, and the
floors of the valleys of the torso supporting ~ection are
higher than the average height of the floors of the valleys
of the head or leg supporting ~ections. Unfortunately,
however, the pressure reduction capabilities of this pad
ars significantly lower than the pressure reduction
capabilities of static air or water support pads.
What i~ needed, ~herefore, is a convolu~ed ~oam pad
which is easy to ~anufacture and provides high pressur~
area reduction capabilities comparable ~o the ~tatic air
and water ~upport pads.
Summarv of the Invent~n
~he present invention solves these problems by
providing an e~sily manufactured convoluted foam pad
having pressure redis~ribution capabili~ies compara~le ~o
the ~tatic air and water ~upport pads and a ~ethod of
manufacturing the ~ame.
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One embodiment of the invention is a convoluted foam
pad for 6upporting at least part of a human body having a
solid flat lower face and a flat upper surface wherein at
least one area of the pad provides less resistance to the
weight o~ the body than other areas of the pad. Desirably,
the area providing this decreased resistance corresponds to
a protrudin~ portion of the body, thereby allowing the body
to sink farther into the pad.
Another embodiment of the ~nvention ~s an elongate
convoluted foam pad ~or ~upporting a reclining human body
on a bed. ~he pad include~ an area for supporting the
~houlders of a body, an area for supporting the tail
portion of the body and a general support area surrounding
the shoulder and tail support ~reas for ~upporting the
remainder of the body. Each support area i~ formed by
flat-topped peaks arranged in rows, wherein each peak in
the same row is spaced from any adjacent peak by a valley.
To decrease the average pressure levels on the
shoulder and tail portions of the body, the average valley
thickness (i.e., the average vertical distance between the
valley ~loors ~nd the bottom of the portion of the pad
directly beneath the respective valley floors) of the
valleys in both the shoulder support area and the tail
~upport area are less than the average valley thickness of
the valleys in the general ~upport area. This diminished
valley thickn~ss has the dual e~fect of r~duoing th~
resistance of the~ pad to the weigh~ of the tail and
~houlder portions of the body and permitting th~ tail and
6houlder areas of the body to 6ink farther into the pad.
-~: 30 T~e increased de~ormation of the pad i~ slgni~icant in
that, as the tail and shoulders of the ~ody ~i~k further
:into the pad, the middle bac~ ~and extra~ities exert
greater pressure against the genexal ~upport area of the
pad. In addition, the farther the tall ~nd ~houlder
: ~35 portions of the body ~ink into the pad, th~ greater the
amount of total ~urface araa of ~he pad in contact w1th the
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tail and Ghoulders portion~ of the body, re~ulting in a
decrease in the avera~e amount of resistance pressure
exerted by the pad per ~quare inch in th~se critical areas.
Desirably, the pad has a flat upper face fonmed by the
flat tops of the peaks of the pad which all lie
substantially in a single plane and a ~olid flat lower
face, without holes or cavities. ~he pad is desirably made
from an open cell ~xpanded plastic polyurethane foam with a
density of between 1-3 pound~ per cubic foot, and has a
peak thickness of one inch or greater.
Another aspect of the invention i6 a method of
manufacturing convoluted foam pads. The method includes
compressing a foam block between two rollers having
radially extended fingers of varying effective height~.
The compressed block iæ then cut into two halves to form
pea~s and valleys. As a result of the varying effective
heights of the fingers of the rollers, the peaks will have
varying peak heights and the valleys will have varying
valley floor heights. The tops of the peaks are then cut
off to create areas having lower volu~es of foam than other
areas. These low foam volume areas will tend to provide
less resistance to pressure than the areas of the pad
having a higher volume of foam.
Desirably, the tops of the peaks are cut ~o the top
of each peak will b~ in ~ubstantially the ~ame plane.
Wh~re some of the corners of the peaks are connected by
webbing, the methcd may also include the ~eparating ~ome of
the peaks connected by webbing to decrea~e the resistance
of the locale including the 6eparated peaks to pres~ure.
Brie~ Descr ption o~ the prawin~s
These ~nd other features of the invention will now be
described with re~erence to drawings for preferred
embodiment which i in~ended to illu tra~e, and not to
limit, the in~ention, and in which:
Figure 1 is a per6pective view illustrating a foam
block being inserted between a pair of cylindrical rollers:
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~322~24
Figure 2 is an enlarged partial perspective view
illustrating the fingers of the roller~ of Figure 1;
~igure 3 is an enlarged exploded perspective view of
one of the fingers of Figure 2;
Figure 4 is an illustration of two convoluted halves
of a block after ~n~ertion into the apparatus of Figure 1;
Figure 5 illustrates the fit between the halves of the
block of Figure 4;
Figure 6 illustrates the topping-off of the peaks of
one of the halves o~ Figure 4;
Figure 7 illustrate-~ the half of Figure 6 after being
saw cut;
Figure 8 illustrates the clip cutting of the half of
Figure 7;
Figure 9 is a ~chematic plan view illustrating the
general spacing of the tail and shoulder regions of a bed
pad made in accordance with the principles of the present
invention;
Figure 10 is a schematic plan view of a pillow made in
~0 accordance with the principles of th~ present invention
illustrating the ~hape of the head and ~eck ~upport ~rea in
phantom;
Figure 11 i5 a schematic plan YieW of a w~eelchair pad
~ade in accordance with the principles ~ the pre~ent
invention illustrating the ~hape of the buttock and thigh
~upport area in phantom: .
Figure 12 is a per pective vî~w of the pillow of
F~gure 10;
Figure 13 i~ a per~pective vi~w o~ the wheelchair pad
of Fi~ure 11;
Figure 14 is a perspective view of ~he bed of ~i~ure
9;
~ igure 15 is a sectional view t~ken along line 1~-15
o~ Figure 14 illu~trating the varying v~lley thicknesses of
the di~ferent areas o~ the bed pad;
~igure 16 i8 a per~pective view illu~trating a foam
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block being inserted between a pair of cylindrical rollers
of an alternative configuration;
Figure 17 i8 an enlarged partial perspective view
illustrating the fingers of the rollers of Figure 16;
Figure 18 i8 an illustration of two convoluted halves
of a block after insertion into the apparatus of Figure 16;
Figure 1~ is a perspective view of one of the halves
of Figure 18 after being saw-cut;
Figure 20 is a sectional view taken along line 20-20
of Figure lg illu~trating the varying valley thicknesses of
the different areas of the mattres~;
Figure 21 is a perspective view illu trating a foam
block being inserted between a pair of cylindrical rollers
of a second alternative con~iguration;
Figure 22 iB an enlarged partial perspective view
illustrating the fingers of the rollar6 of Figure 21;
Figure 23 is an illustration of two convoluted halves
of a block after insertion into the apparatus o~ Figure 21:
Figure 24 is a perspective view o~ one of the halves
of Figure 23 a~ter being saw-cut; and
Figure 25 is a cectional view taken ~long line 25 25
of Figure 24 illustrating the varying valley thicknesses o~
the different areas of the pad.
Detailed~esc~tion 4~ ~h~ ~xe~rred ~mb~im~n~
Figure 1 show~ an apparatus 11 for ~anufacturing
convoluted foam pads. The apparatus 11 includ~ ~ pair of
cooperating parallel rOller5, 13 and 14, each of which has
a cylindxical body and an undulated ~urface. A~ more
clearly ~hown in Pigur~ 2, th~ undulated ~urface of each
roller i8 formed by a plurality o~ ger~ 15 o~ generally
: rectangular cro~s Lection extending radi~lly from its
cylindrical body. Naturally, if desir~d, ~nother ~hape of
~inger could be utilized. The ~ingers 15 ~re arranged in
vertical and horizontal rows. Fingers in vertically
adjacent rows are staggered vertically a circ~ferential
di~tance appxoximately e~ual to ~he vertical width of the
~32242~
~inger~. Fingers in horizontally adjacen~ row~ are
staggered horizontally a circumferential di~tance
approximately equal to the horizontal width of the fingers.
The rotating rollers, 13 and 14, compresR and drive
the foam block 19 agains~ a cutter (a guard 17 for which
is shown in Figure 4~. As shown in Figure 1, the upper
roller rotates counterclockwise and the lower rotates
clockwise. This rotation is synchronized 50 the fingers 15
of the respective rollers are opposed by the spaces 21
between the ~ingers of the opposite roller, rather than
directly by its fingers 15. In addition, to obtain pads
which are virtually a mirror image of one another, all
fingers 15 on a given side o~, and vertically adjacent to,
the spaces of one roller have an effective height equal to
the effective height of the finger of the opposing roller
which opposes the space.
As best seen in Figuras 2 and 3, the radial height of
each of the fingers 15 is equal. Selected fingers,
however, have a greater effective radial height as a result
of one or more flat rectangular caps 23 or plates being
~ecured to the radial outer end of the finger by a bolt 25
threadably ~ecured within a tapped bore 27 extending
xadially through the center o~ the finger. Naturally, the
thicknes~ of the caps 23 can be varied depending upon th~
given application. A counter~ink 29 may be provided around
the bore 27 of the outer cap r ~ that the head of the bolt
2S is flush with the outer face 31 of the cap.
R~ferring to Figure 4, after the foam block 19 is
compressed ~etween the roller6, it is driven against the
cutter ~not shown) which 61ices the block 19 into halves
33. As ~hown in Figure 5, the resulting halve~ 33 are
virtually a perfect mirror imag~ of one ano~her, with each
peak 35 of one half corre~ponding to an adjacent p~ak 37 o~
equal ~ize on the other hal~. On ~he other hand, the
variance in the ef~ective height of the ~ingers 15 results
both ~n peak~ with varying peak heights P, ~nd valleys with
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varyi~g valley floor heights V Because the pad is cut
from a 6ingle block 19, however, the 6um of the valley
Ploor height and the corresponding peak heiyht will equal a
constant, so long as the block being cut i6 of uniform
thi~kness.
By varying the effective height of the fingers less
than one quarter of an inch, the he~ghts of the peaks 42 of
the re ulting foam halves 33 can be var~ed 3-4 inches.
Naturally, since the block halves 33 are a mirror image of
one another, the base height o~ the corresponding valleys
44 will ~ary an equal amount. Thu~, although the peak to
base ratio of the pad can be made to vary widely,
essentially the ~ame volume of foam is present to r~sist
the weight ~f a given area of the body ~upported by the
pad.
As shown in Figure 6, the tops 39 of the peak~ 42 are
then rem~ved with a band saw 41 or other 6uitable cutting
device, thereby leaving a rectangular pad 43 with a flat
solid lower face 45 and a substantially flat upper face 47
comprised o~ the flat tops 49 of the peaks 42. As ~hown in
Figure 7, the pad 43 comprises adjacent row~ of peaks 42 of
generally rectangular cross section, each o~ which ~re
separated by valley~ 44, also of generaliy rectangular
cross section. 8ince the peaks 42 in adjacent rowæ are
staggered, the overall e~fect is a checkerbDard pa~tern,
with the corners of the peaks 42 in ad;acent row~ connected
by webbing 51 extending between the peaks 42 to the floor
of the valleys 44. The webbing 51 between some peaks 42
wi}l extend from the top of the peak downward to ~he floor
of the ~alley between them. Between other peaks 42,
especially those with lGwer vall~y heights, the webb.ing 51
will be ~paced below the tops of ~he peak~ 42 an~ extend
downward tG the floor of the valley between th~m. For
example, re~erring to Yigure 7, a peak 57, ~n ~ row of
peak~ 59 be~ween a ~econd and third row of peaXs, 61 and
63, re~pectively, has a ~ir corner 65 connected by
~22~4
webbing 51 to a corner of a ~irst peak 67 in the ~econd row
61 and a second corner 69 which is connected by web~ing 51
to a corner of a ~econd peak 71 in the second row 61.
Likewise, the peak 57 has a third corner 73 wh~ch is
connected by webbing 51 to a corner of a first peak 75 in
the third row 63 and a fourth corner 77 which is connected
by webbing 51 to a 6econd peak 79 in the th~rd row 63.
~ o obtain two senerally uniform pads from a 6ingle
block 19 it is desirable that the tops of the peaks 42 are
cut off at a point midway between the tops of the peaks 42
and the floor of the valleys 44. Although each of the
remaining flat-topped peaks 42 will have a uniform peak
height, the base height of the valley floors varies in
proportion to the effective height of the finger which
cr~ated it. Since the pad 43 has a flat lower face 45,
the peak height of each peak is equal to its peak thickness
(i.e., the vertical distance between the top of the peak
and the bottom o the portion of the pad 43 directly
beneath the peak). Naturally, if the lower face of the pad
43 included an opening beneath the peak, this would not be
the case. ~ikewise, the valley floor height of each valley
oP the illustrated pad 43 i8 egual to its valley thickness
(i.e., the verkical distance between the valley floor and
the bottom of the poxtion of the pad 43 directly beneath
~5 the vall~y floor)~ If the lower ~ace 45 of the pad 43
included an opening beneath the valley floor, h~w~ver, this
would not be the ca~e.
By increasing the ef~ective height of the fingers 15
which correspond to ~he ar~a~ of the pad 43 suppor~ing the
~houlder and tail portions of the body, taller peaks 42 and
lswer valleys 44 are ~or~ed in tho~e arsas:of the pad 43~
By evening out the height o~ the peaks 42 by ~opping them
: off at a cer~ain height, one i8 l~ft with a ~m~ller volume
of foam to resi~t the we~ght of the that portion of th~
;35 body. It has been found that the ~maller ~he volume of
foam ~n a given area, the ~maller the level o~ resl~tanc~
13224~
of the foam to the weight of the body will be. By
decreasing the volume of foam beneath these heavier
portions of the body, the more the weight of the body
portions to overcome the resistance cf the pad and sink
into the ~oam. This, in turn, increases the 6urface area
of the pad in contact with the body portion, thereby
further diminishing the level of pressure exerted on the
ckin of the body per unit area. In addition, ~ince both
the shoulder and tail portion of the body protrude farther
than the lighter portions, as the shouldar and tail
portions sinX into the pad, the pressure of the pad on the
less protruding portions (e.g., the middl2 of the back)
will increase, thereby relieving pressure from the tail and
shoulder portio~s of the body.
The pad of the present invention can be mad~ from a
wid~ variety o~ types o~ foam of varying denslty and
thickness. It has been found, however, that the desired
combinatio~ of cushioning and support is obtained from an
open cell expanded plastic polyurethane foam with a density
of between one and three pounds per cubic foot, preferably
1.5 pounds. The peak and valley thickness of the pad 43 is
desirably 6uf~icient to ensure that the body supported by
the pad does not bottom out. For a bed pad 43 having a
density of between 1-3 pounds, a peak thicknes~ of between
3-5 inches, and a valley thickness of ~pproxi~ately one
half of an inch has been found to be sufficient to prevent
bottom~ng out in most instances. In home health care
applications, however, significant benefits can be realized
~rom a pad with a peak thickness as low as one inch and a
valley thickn~ss as low as one-eighth of an inch, which
: imposes ~ concavity to the bed surface for comfort, as
: opposed to ther~peutic purposes~
At times, in addition to the etandardized pressure
reduction capabilities o~ the pad 43, it is desirable in
the case o~ burns or other localized injury to decr~ase the
level of pre6sure resistance in ~ given area of the pad.
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As illu~trat~d in Figure 8 thi~ may be accomplished by
cutting the webbing 51 connecting the corners o~ the peaks
42 in adjacent rows to ~eparate the peaks 42. Th~s has the
effect of decreasing the "hammock effect" between the
separated peaks. ~he hammock effect results from
neighboring peaks resisting the tendency of a connected
peak to be compressed below their level, much like two
trees resist the tendency of a hammoc~ to sag to the ground
in respon-~e to the weight on th2 hammock. The cutting of
the webbing 51 largely eliminates this effect, thereby
decreasing the capacity of the locale which includes the
separated peak to resist the weight of a body.
Referring to Figure 9, there i5 shown a schematic view
of a bed pad 43 manufactured in accordance with the
principles of the present invention. As further ~hown in
Figures 14, the bed pad 43 will generally have an overall
length o~ between 60-90 inches and a width of between 25-40
inches, depending upon the length and width of the mattress
being covered. For specialty beds, the length could vary
between 30-90 inches and the width could vary between 20-90
inches. The illustrated pad 43 has a length of
approximately 72 inches and a width of approximately 35
inches~ The shoulder ~upport area 81 and tail ~upport area
83 of the pad 43 are positioned to correspond to the normal
~5 position o~ the shoulder and tail portions o~ the body of
- the intended user and are surrounded by the general support
area 84 of the pad 43. The shoulder ~upport area 81 of the
illustrated pad 43 is Fpaced twelve inches ~rom one end 85
of the pad, is centered betwe~n the ~ides 87 of the pad and
has a width of 28.35 inches and~a length of 14.85 inches.
The width and length of the ~houlder support area B1, as
well a~ its ~hape may vary, ~ut preferably the w~dth is
between 25 and 33 inches, the length i~ between 12 and 17
inches and the shape is generally that of ~ ~u~hroom.
There is a gap of 6 inches be~ween the ~houlder and tail
5upport areas of the pad 43. The tail ~upport ~rea 83 of
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the illu~trated pad 43 i~ elliptical ln ~hape, is centered
between the sides of the pad, has a width of 17.55 inches
and a length of 12.15 inches. Thi~ spaces the tail ~upport
area 27 inches from the other end 89 of the pad. As with
the shoulder support area 81, the width and length of the
tail support area 83, as well as its ~hape, may vary, but
preferably, the width is between lS and 20 inches, the
length iB between 10 and 17 inches, and the area is
generally elliptical or circular in shape. Naturally, an
n additional support area could be added for the heels, if
desired.
Although the ~izes of the peaks 42 and valleys 44 of
the pad 43 ~ay be varied, the illu~trated pad has a uniform
distribution of peaks of square cross ~ection. The peaks
42 of the general 8upport area, the shoulder 5upport area
81 and the tail support area 83 all have a peak thickness
of 4 inches and a square ¢ross ~ection with a width of 1.35
inches. As best seen in Figure 15, to provide the desired
low~red resistance and body contouring features, the valley
thicknesses of the ~houlder and tail ~upport sections c~
the pad are less than the valley thickne~ses of the general
~upport area o~ the pad. Specifically, the valley
thickness for both the ~houlder support area 81 and the
tail ~upport area 83 is one half o~ one inch, while th~
valley thickness for the ~eneral support area is 3 inches.
Advantageously, the bed pad 43 i~ fo~med by ~eans of
inserting a block 19 o~ foam lengthwise through a roller
having a circumference equal to the length oP the bed pad
43, so that a pair o~ pads is formed by a single turn o~
th~ roller. Thus, the illustrated pad 43 would be ~ormed
with two roll¢r~ each having a circumrerence o~ 72 înches.
The fingers 15 of eaoh roller corre ponding to the general
support area of the pad 43 advantageously ex~nd radially
2.5 inches fro~ the cylindrical core of the roller and have
a ~guare cross section with a width of .9 inches. ~his
width may vary, but is preferably between 1.~5 and 2.0
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1~22~2k
inches. The ~pace between the opposing rollers, 13 and 14,
is roughly one quarter o~ an lnch, with this distance
being xhortened where the rollers are provided with caps.
The fingers 15 of the roller corresponding to the ~houlder
support area 81 and the tail ~upport ~rea 83 are
advantageously formed by fingers 15 with an effective
finger height of 2.6875 inches, resulting from the placing
of caps 23 having a combined thickne6s of 3/16 o~ an inch
onto the end of the fingers 15, The resulting bed pad 43
is 4 inches thick with a valley thickness of .5 inches
which is sufficient to prevent b~ttoming out in most cases.
In a test comparing a bed pad, generally conforming to
the specifications s t forth above, with ~tatic water,
static air and other convoluted foam support pads, the bed
pad of the present invention no~ only demonstrated pressure
relief capabilities, in the scapulae, sacrum and trochanter
areas, superior to the other convolut2d foam bed pads
tested, but demonstrated pressure redistribution
capabilities in these areas comparable to the static air
and water support pads tested. Speci~ically, the pads
tested are as follows:
Model
Pesination Manufacturer Trademark _ No. _~ype
25 Foam #l* Pre-Foam, Inc. HIGHFLOAT 5095020 ~oam
Water Lotus Healthcare
Products LOTUS HM3666 water
30 Air Gaymar Industries,
~ncO SOF-C~RE SC-402 air
Foam #2 Bio Clinic Company BIOGARD 669030 foam
35 Foam #3 Span Amerlca
Medical Systems,
: Inc. GEO-MATT 50960-581 foam
Foam #4 Pre-Foam, Inc. PR~VENT P141 foam
~ * Foam Pad #1 i~ a pad ~ade in accordance wi~h the
: principles o~ the present inYe~tion.
summary oX the test results are ~et ~orth below in
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the following table:
. P~essure Lçvçl
Pad Scapulae Sacrum Trochanter
~esiqnation lmm Hq) ~mm Hq~ (mm Hq~
Foam #1* 24.02 28.28 44.22
Water 22.44 25.96 46.74
~ir 32.36 33.15 40.57
Foam #2 29.~6 34.40 47.17
Foam #3 23.04 31.97 49.73
Foam #~ 28.04 36.88 45.97
Thus, there is provided a convoluted foam bed pad
which is both ~imple and inexpensive to manufacture and
which provides hîgh pressure redistribution capabilities
comparable to static air and water support pads.
The method and teachings of the present invention can
be used to manufacture pads of a wide variety o~ shapes and
sizes. Specifically, the method of the present invention
c~n be used to manufacture pillows and wheelchalr pads
which conform to the 6hapP of the body, thereby ~ncreasing
the total surface area of the pad resi~ting the body weight
of the us~r.
Flgure~ lO and 12 show a p~llow g3 having a
generally T-6haped head and neck 6uppor~ ar~a 95 and ~
general 8upport area 97. A5 with the be~ pad 43, the
pillow 93 is formed by peak~ 99 ~rranged in row~, wherein
each peak ha a flat top, i~ ~paced from: any ~djacent peak
in the ~ame row by a valley 101 and has gen~rally identical
peak thicknes6es. The tops of :the pe~ks ~re all in
~: suhstantially th~ sa~e plane, thsreby provid~ng a pillow 93
of pl~asing appearance which can be used wi~ stand~rd
pill~ covers. ~o ~ncrease the pillow'~ oapacity to
conform to the head an~ neck o~ the uæerr ~khe average
valley thickness of the head and neck ~upport rea 95 is
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less than khe average valley thickness of the general
support area 97. Although the dimen~ions of the pillow 33
can obviously be varied widely, depending upon the desired
application, the illustrated pillow 93 has a width of 21
inches and a depth of 14 inches, with a uniform peak
thickness o~ 4 inches. The truncated stem 103 of the
T-shaped head and neck upport area 95 extends toward the
center of tbe pillow 93 ~rom one end 105, i~ centered
between the 6ides 106 of the pillow and has a width of
4.05 inches. The crossbar 107 of the T-shaped head and
neck support area 95 extends from one ~ide of the pillow to
the other, is ~paced 4.05 inches frsm the end of the pillow
from which the stem portion extends, and has a depth of
4.05 inches. Thi~ spaces the stem portion 5.90 inches
from the opposite end 111 of the pillow. The desir~d
contouring e~fect ~ay be obtained from a T-shaped head and
neck upport area 95 with an average valley thickness of
1/2 an inch and the general æupport area 97 with a uniform
valley thickness of 3 inches.
Figures 11 and 13 show a wheelchair pad 113 having a
generally U-shaped buttock and thigh support area 115 and a
general support area 117. As with the pillow 93 and bed
pad 43, the wheelchair pad 113 is formed by psaks 119
arranged in rows, wherein each peak has a ~lat top, is
~paced from any adjacent peak in the ~ame row by a valley
121 and has generally identical peak thickne~ he tops
of the peak~ are also aIl in substantially the 6ame plane,
thereby providing a whe~lchair pad 113 of plea~ing
appearance. To increa~e the wheelchair pad'~ capacity to
conform to the buttocks and thigh~ of the user, the av~rage
valley ~hicXne~s o~ the but~oc~ and thigh ~upport area 115
is less than the average valley thickness o~ the general
~upport ar2a 117~ Although the di~ensions of ~he
wheelchair pad 113 can obviously be varied, depen~ing upon
the size of the chair and the user, the illustrated
wheelchair pad 113 has a width of 18 inches ~nd a depth Or
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16 inche6, with a uniform peak thickne~s of 4 1/2 ~nches.
The legs 123 o~ the T-shaped buttock and thi~h ~upport area
115 extend toward the opposite end of the wheelchair pad
from one end, are spaced 2.2g5 inches from th~ sides of the
wheelchair pad and have a w~dth of 4.05 inches. An arcuate
connecting portion 125 connectc the two legs of the
U-shaped buttock and thigh support area 115, i6 apaced 1-
1/4 inches from the opposite end of the wheelchair pad, and
has a width of 4.05 inches. The desired contouring effect
may be obtained from a U-shaped buttock and thigh 5upport
area 115 with an average valley thickness o~ 3/4 inches and
the general support area 117 with a uniform valley
thickness o~ 3 1/2 inches.
As illustrated in Figures 16-20, the method and
teachings of the pre~ent in~ention can be used to
manufacture an anatomically, conformable convoluted foam
pad, particularly adapted to be used as a mattress, rather
than a mattress overlay.
Figure 16 shows an apparatus 126 for ~anufacturing
convoluted foam mattresses. ~he apparatus 127 includes a
pair of cooperating parallel rollers 127 and 129, each of
which has a central undulated ~urface 131 and a cylindrical
body 133, including a pair of ends, 135 and 137. ~s shown
in Figures 16 and 17, at each end of the roller is an
expo~ed cylindrical sur~ace 139. The undulated sur~ace 131
of each roller is foxmed by a plurality of fingers 141 of
generally xectangular cross-~ection extending radially ~rom
it5 cylindrical body 133. The fingers 141 in vertically
adjacent rows are 6taggered vertioally a circumferential
distance approximately e~ual to the vertical width of the
~inger~ 141, ~nd fingers 141 in horizontally ~djacent rows
are ~taggered horizontally a circumfer~n~ial di~tance
approximately equal to the horizontal width o~ the fingers
141.
The rotating rollers~ 127 and 129, compress and drive
a foam block 143 against the cutker (a guard 144 for which
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is ~hown in Figure 18). The upper roller 127 rotate~
counterclockwise and the lower roller 129 rotate6 clockwise
in a synchronized manner 80 that the fingers 141 of the
resp~ctive rollers are opposed by the spaces between the
fingers of the opposite roller. In addition, tha
cylindrical ~urfaces 139 of the ends, 135 and 137 of the
upper roller 127 are opposed by the cylindrical surfaces
139 o~ the respective ends, 135 and 137, of the opposite
roller 129~ All fingers 141 on a given side o~, and
vertically adjacent to, tha 6paces of one roller have an
effective height equal to the effective height of the
finger of the opposing roller which opposes the space. As
shown in Figure 17, the radial height of most of the
fingers 141 is equal. Selected finger6 141, however, have
a greater effectiYe radial height as a result of one or
more ~lat, rectangular caps 145 or plates being secured to
the outer end of the ~inger.
As shown in Figure 18, after the foam block 143 is
compressed between the rollers, 127 and 129, it is driven
against the cutter (not ~hown) which ~lices the block into
halves, 149 and 151, which are a perfect mirror image of
one another, 80 that each peak 152 of one half corresponds
to an adjacent peak of equal ~ize on the other half.
However, variance in the effective height o~ the finger~
141 results both in peaks with varying peak thicknesses
and valleys with vaxying valley thicknesses. Because the
mattress is cut from a single block, however~ the sum o~
the v~lley thickne~ses and the corresponding peak
thicknesses will equal a constant, ~o long as the block
being cut i~ of uni~orm thickness. Likewise, the
cylindrical surfaces 139 of the ends of each roller
co~press the foa~ in identical amount, ~o that the portion
of the bl~ck 143 compressed ketween the cylindrical
surfaces 139 of the rollers is rlat, with each portion of
the mattress corre~ponding to the cylindrical ~uY~ace of
the ends sf the rollers ~orming an elongate rail 153 of
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identical thickness extending the length of the mattress.
The tops of the peaks formed by the cooperating
undulating surfaces are then removed with a band saw or
other suitable cutting device at a point ~idway between the
tops of the peaks and the floor of the valleys, in the
manner illustrated in Figure 6, leaving an elongate
rectangular mattress 155 (Figure 19-20) with a flat, solid,
lower face 157 and a substantially flat, upper face 159
comprised of the flat tops of a plurality of peaks 161 and
a pair o~ elongate rails 153 extending the length of the
mattress. As shown in Figure 19, the portion of the
mattress between the rails 153 comprises ad~acent rows of
peaks 161 of generally rectangular cross-section, each o~
which are separated ~y a plurality of valleys 162, also
generally rectangular cross-section. Since the peaks 161
in adjacent rows are staggered, the overall e~fect is a
checker board pattern with two flat elongate borders formed
by the mattress' two rails 153.
By increasing the effective height of the ~ingers
which correspond to the areas o~ the pad supporting the
shoulder and tail portions of the body, taller peaks and
lower valleys are formed in tho~e areas of the ~attress.
By evening out the heights of the peaks 161 by topping them
off at a certain height, one is left with a ~maller volume
o~ foam in the shoulder and tail 8upport areas to resist
the weight of those respective portion of the body and, as
a re ult, the ~attress provide~ less resistance ~o these
heavier body portions, thereby increasing the ability of
the ma~tress to conform to ~he anatomy of the user.
Xeferring to Figure 19, the ~attress 155 ~anufactured
in accordance with the principle of the present invention
desirably haæ a thicXness in excess of 5 inches, an overall
length of between 30 and 90 inches and an ov~raIl width of
between 20 and 90 inches, depending upon ~he leng~h and
width of the bed frame, and the len~th and width o~ the box
springs being utilized. For ~pecialty bedsO the length
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could vary between 30-90 inches and the width could vary
between 20-90 inches. Likewise, the ~lat rails 153 of the
mattress 155 desirably have a width of between 2 and 6
inches and may extend over any portion of the length of the
mattress, but desirably at least half o~ the mattress'
length and, preferably, the entire length of the mattress.
The rails 153 have a greater volume of foam per unit area,
and provide an area of increased resistance, to provide
support when getting on to or of~ of the mattress. In the
illustrated mattress the rails 153 have a width of 3 inches
and extend the length of the mattress. The illustrated
mattress has a length of approximately 72 inches and a
width of approximately 35 inches.
A mattress manufactured in accordance with the
principles of the pressnt inventio~ can alternatively be
designed so that breaks in the flat rails are positioned to
correspond with the hinge points about which most hospital
beds are bendable. Such breaks in the flat rails, if
configured to the same peak and valley dimensions of the
general support area of the mattress ~ake the mattress
easier to bend with the hinged bed at that point.
Between the mattress rails 153 is a general support
area 163. The general support area 6urrounds a shoulder
~upport area 165 and a tail ~upport area 167 which are
positioned to correspond to the normal position of the
~houlder and tail portions of the body of the intended
user. The ~houlder cupport ar~a 165 of the illustrated
mattrPss is spaced 1~ inches from one end of the pad, it is
centered between the sides of the mattres6 ~nd has a width
o~ 28.35 inches and a l~ngth of ~4.85 inches~ The width
and l~ngth of the Rhould~r support area 165, a~ w~ll as its
~hape may vary, but preferably the width i~ be~weQn 25 and
33 inches, the length i~ between 12 and 17 inch~s and the
shape is generally that of a ~uhroom. There i~ a gap o~ 6
inches between the shoulder and tail ~upport area~, 165 and
167 t respectively, ~f the mattres~. The ta~l ~upport area
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167 of the illu~trated mattress is elliptical in ~hape, it
is centered between the sides of the mattress and has a
width of between 17.55 inche~ a~d a length o~ 12.15 inches.
This spaces the tail ~upport area 167 27 inches from the
other end of the mattress. As with the ~houlder support
area 165, the width and length of the tail ~upport area
167, as well as its shapQ, may vary, but preferably, the
width is between 15 and 20 inche~, the length is between 10
and 17 inches, and the area i8 generally elliptical or
circular in shape.
In some applications, it may be desirable to u~e a
longer foam block in manufacturing the mattress, so as to
take advantage of the dif~erence between the circumference
of the rollers, 127 and 129, and the length of the block.
As will be readily appreciated, this will result in a
greater angular rotation of the rollers, 127 and 129, to
cause, for example, a repeat of the ~houlder support area
pattern. Where block length i8 planned to exceed the roll
circum~erence, a portion of the shoulder support area can
be designed to provide ~or an additional heel support araa
running approximately 2/3 of the distance across the pad
involving up to the last 12" of the pad. Such a h~el
Eupport area wou~ld provide a general 60ftenlng of this
portion of the pad and ac~ommodate ~he heels and bones of
2S the lower leg. When such alternate heel fiUppOrt areas are
provided and configured in a fashion e~nsi~tent with the
peak and valley dimensions of the shoulder and tail
~upporting areas, ~ore o~ the total weight of the lower leg
will be supported by the back of the pat~ent~s legs
redi ~ributing potentially high localized pressure points
which typically exist at the heel ~nd bones o~ t~e ankle.
~uch provisions may prove particularly ben~iclal to
patient~ being treated for vascular ulcers of the lower
leg.
Becau~e the illustrated ~attress posce~se~ a flat,
rectangular overall conflguration, it may ~e di~icult to
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determine its correct head-to-~oot end orientation if
cov~red in a permanent uphol~tered cover. To mitigate this
potential problem, in ~uch instances, ~t ~ay be desirable
to use the principles of the present invention to provide a
second shoulder ~upport area at the opposite end of the
block from the first shoulder ~upport area, 80 that the
first and second shoulder support areas are symmetrical
about the tail ~upport area.
This modification provides the ~ame general ~houlder
and tail support for the body without regard for head-to-
foot end orientation. At the same time, because of the
lack of body mass and projection in the general area of the
back or side of the knees, there is very little increased
deformation in the area of the unused should~r support
area and, no significant change in the pressures recorded
at the primary bony prominent areas of the body.
Although the sizes of the peaks 161 and valleys 162 of
the mattress may be varied, the convoluted portion of the
illustrated mattress has a uniform distribution of peaks of
square cross-section. The peaks 1~1 of the general support
area 163, the shoulder ~upport area 16S and the tail
support area 167 all have a peak thickness of 6 inches in a
~quare cross-~ection with a width of 1.35 inches. As best
seen in Figure 20, to provide the desired lower re~i~tance
and body contouring eatures, the v~lley thicknesses of the
~houlder and tail ~upport sections, 165 and 167, of the
mattress are less than the vaIley thicknesses of the
general support area 163 of the mattress. Spec1~ically~
the valley thickness for both the ~houlder ~upport area 165
and the tail ~upport area 167 is ~2 of one lnch while the
valley thickness for the general 8upport area i~ 3 inches.
Referring now to Figures 21-25, the principles of the
present inuention can be u~ed to fflanufacturP an
anatomically conforming bed overlay or posturi2er for home
health care application~.
Figure 21 6how~ an apparatus 169 ~or ~anufacturing
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convoluted f~a~ posturizer6. The apparatus include6 a pair
of cooperating rollers, 171 and 173, e~ch of which has a
cylindrical body 175. Each roller includes three sections
176 having an undulated surface and a pair of æections 177
formed by rows of ribs. The undulated surface of each
roller is ~ormed by a plurality of fingers 179 o~ generally
rectangular cross-section extending radially from its
cylindrical body 175. The fingers 179 are arranged in
vertical and horizontal rows. The fingers 179 in
vertically adjacent rows are staggered vertically a
circumferential distance approximately equal to the
vertical width of the fingers. Fingers 179 in horizontally
adjacent rows are staggered horizontally a circum~erential
distance approximately equal to the horizontal width of the
fingers. ~he ribbed sections 177 are formed by vertically
spaced ribs 181, each of which extends the length of the
section and extends radially outward ~rom the cylindrical
body 175 of the roller. The ribs 181 are spaced vertically
from one another, a circumferential distance approximately
equal to the vertical width of the ribs 181.
Advantageously, the rollers 171 and 173 are configured
so that when the side of a fsam block 183 is inserted
between the rollers, the rollers, 171 and 173, form a
constant pattern, regardless of the width of the block 183.
This enables the same rollers to be utilized to form
- posturlzers having a width corresponding to a twin, queen
or king-size bed.
The rotating rollers 171 and 173 compres~ and drive
the foam block 183 against a cutter (a guard 185 for which
is shown in Figure 23~ hown in ~igure 21, the upper
roller 171 rotates counterclockwi e and the low~r roller
173 rotates clockwi~e. This rotation is ~ynchroniz~d ~o
that the finger~ 179 of the respective roller~ are opposed
by the Epaces betwee~ the fingers of the opposik~ roller,
rather than directly by it~ ~ingers 179. Likewise, the
ribs 181 of the upper roiler 1~1 are opposed by the ~paces
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between the ribs 181 of the lower roller 173, rather thandirectly by its rib6 181. As best ~een in Figure 21, the
effective height of each of the finger6 179 i~ equal and
the radial height of each o~ the ribs 181 is equal,
although the effective height of each of the ribs 181 i6
greater than the effective height o~ each of ~he fingers
179.
Referring to Figure 23, after the foam block i~
compressed betw~en the rollers, it is driven against the
cutter (not ~hown) which 61ices the block into halves 187.
The resulting halves 187 are a perfect mirror ~mage of one
another with each peak 189 o~ one half corresponding to an
adjacent peak 189 of egual size on the other hal~, and each
xib 191 of one hal~ corresponding to an adjacent rib 191 of
equal size on the other half. Since the effective height
of each o~ the fingers 179 is equal, each p~ak 189 has an
identical peak height and each valley 193 has an identical
valley thickness. Likewise, 6ince the effective height o~
each of the ribs 177 is equal, each rib 191 of the
posturizer has an identical peak height and each valley has
an identical valley thickness.
~he tops of the peaks and ribs are removed with a band
saw or other suitable cutting device at a point midway
between ~he tops of the peaks ~nd ~he floor o~ the valleys
leaving an elongate rectangular posturizer 195 (Fi~ure 24-
25) with a flat, solid, lower surface 197 and a
substantially 1at, upper 6ur~ce 199 compri~ed of the flat
tops of the peaks 189 and the flat ~ops of the ribs 191.
As shown: in Figure 24, the posturizer is ~ormed by ~ head
30 suppbrt area 201 adjacent one o~ the ends o~ ~he posturlzer
for supporting the head o~ a body, a ~houlder support area
203 adjacent the head ~upport area 201 for suppor~ing the
shoulder portion of a body, ~ middle back fiUppOrt area 205
adjacent the ~houlder support area 203 ~or supporting the
~iddle b~ck portion of a body, a ta~l ~upport ~rea 20~
adjacent the middle back ~spport ~rea 205 for supporting
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the tail ~ection of a body and a leq and feet support area
20~ adjacent the tail support area 207 and the other end of
the posturizer for ~upporting the legs and feet of a body.
The head support area 201, the middle back ~upport area 205
and the leg and feet 6upport area 209 are formed by
adjacent rows of peaks 213 of generally rectangular cross-
section, each of which are separated by valleys 215, also
of generally rectangular cross~section. The overall affect
of the peaks and valleys is a checkerboard pattern, with
the corners of the peaks 213 in ad~acent rows connected by
webbing extending between the peaks to the floor of the
valleys 215.
In contrast, the shoulder support area 203 and the
tail ~upport area 207 are formed by rows of horizontally
spaced longitudinally extending ribs 217, wherein each rib
is 6eparated from the adjacent rib 217 by a longitudinally
extending valley 219. The overall affect of the ribs and
valleys is a corrugated pattern.
In previous embodiments, the ef~ective height of the
fingers which corresponded to the areas of the pad
supporting the ~houlder and tail 6ections of the body have
been increased to form taller peaks and lower valleys in
those areas of the pad. By topping off the peaks at a
certain height, sne was left with a smaller volume o~ foam
to rasist the weight o~ that portion of the body.
Since the e~ective height of the ribs 181 of the
roller~ i~ greater than the e~fective height of the
~ingers 179, the ribs have a greater peak height and
valleys o~ lower valley thickness than the peaks and
valleys formed by the ~inger~. After the tops of the ribs
and peaks are removed, the ~houlder and tail ~upport ~reas,
formed by the rows of rib~ ~17 and vall~ys 21~, have a
lower foam contenk (i.e., a smaller amount of foam of
uniform density per unit volume) than the head, ~iddle bacX
and leg and feet ~upport area~ 201, 205, and 209,
respectively, formed by the adjacent rows of peaks 213 ~nd
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valleys 215. Accordingly, the ~houlder and tail portion~
of the body are ~ore able to overcome the resistance of the
posturizer and sink into the ~houlder and tail 8upport
areas 203 and 207, thereby increasing the surface area of
the posturizer in cont~ct with the 6houlder nnd tail
portion of the body and diminishing the level of pressure
exerted on the skin per unit area. Likewise, as the
shoulder and tail portion of the body protrude farther into
the shoulder and tail support areas, 203 and 207, of the
pad, the pressure of the head, middle back and leg and feet
support areas 201, 205 and 209 on the less protruding
portions (e.g., the 6ide) will increase, thereby relieving
pressure from the tail and shoulder portions o~ the body.
Referring to Figure 24, the anatomically conforming
posturizer 195 will generally have an overall length of
between 60-90 inches and a width of between 25-40 inches,
depending upon the length and width of the mattress being
covered, and a thickness of between 1-3 inches. Further,
for specialty beds, the length may vary between 30-90
inches and the width may vary between 20-90 inches.
The illustrated posturizer 195 has a length of
approximately 72 inches and a width of approxi~ately 35
inches. The leg and feet 6upport area 209 has a length of
approximately 29 inches. The tail support area 207 has a
length of approxima~ely 11 inches. The middle back 8upport
area 205 has a length of approximately 9 inche~. The
~houlder 6upport area 203 has a length o~ approxi~ately 15
inches, and the head support ar~a 201 has a length of
approximately 9 inches. Further, the po~turizer has a
thicXness of 2 inches and, therefore, a uniform peak height
of 2 inches, a valley thickness o~ 1/4 inch in th~ ~houlder
: and tail ~upport areas 203 and 207, and a valley ~hickness
of 1-1/4 inches in the head, ~iddle back and leg and ~eet
upport area~ 201, 205 and 209. Naturally, the length and
thickness of the support areas ~ay vary depen~ing upon the
average ~ize of the body to be ~upported.
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