Cushion having flexible outer membrane and multi-density resilient foam member therein

A cushion for motor vehicle seating or furniture comprises a flexible outer membrane or cover and a multi-hardness foam member, comprising foam regions of different foam hardness. The foam regions are bonded together along common boundaries and are bonded to the membrane at any boundary therewith, such bonding ocurring during formulation of the foam member and employing the materials of which the foam member is made. The method generally comprises the steps of: (a) providing a flexible membrane having a cavity therein; (b) adding to the cavity in a predetermined sequence a plurality of formulations in liquid form which, when cured, provide a foam article having foam regions of different hardness; (c) and allowing the formulations to cure, bond together at any common boundary between formulations, and bond together at any common boundary between a formulation and the membrane. The method may include the further step of changing to the orientation of the membrane cavity to thereby affect the flow of one or more formulations and determine the shape of the foam region subsequently formed thereby.

BACKGROUND OF THE INVENTION 
1. Field of Use 
This invention relates to a cushion comprising a flexible outer membrane 
and a multi-density or multi-hardness foam member underlying and bonded to 
the membrane and to methods for making such a cushion. 
2. Description of the Prior Art 
U.S. Pat. No. 4,405,681 and No. 4,190,697, both assigned to the same 
assignee as the present application, disclose and claim multi-density foam 
articles and methods for making such articles. Typically, after such 
multi-density foam articles are made, they are then provided with flexible 
outer covers, made of cloth, plastic, leather or the like, which are then 
glued to the foam articles and thus fashioned into cushions, such as seat 
cushions, for motor vehicles, such as cars, trucks, motorcycles or the 
like, or for furniture. In some other prior art arrangements, cushions are 
made by gluing together pre-formed foam blocks of different hardness or 
compressibility and then gluing a flexible covering therearound. 
SUMMARY OF THE PRESENT INVENTION 
The present invention provides an improved cushion, such as a seat cushion 
for motor vehicles or furniture, which comprises a flexible outer membrane 
or cover and a multi-density or multi-hardness foam member, comprising 
foam regions of different density, hardness or compressibility which are 
bonded together and underly or are covered by the membrane and bonded to 
the membrane, such bonding occurring during formulation of the foam member 
and employing the materials of which the foam member is made. The present 
invention also provides improved methods for making such cushions. 
In the improved cushion, the foam member comprises a plurality of foam 
regions of different density, hardness or compressbility, which regions 
are bonded together at their common boundaries by the materials of which 
the foam regions are made. The foam regions are made from liquid 
formulations similar to those described in detail in U.S. Pat. Nos. 
4,405,681 and 4,190,697, hereinbefore referred to. The cushion further 
comprises a flexible outer membrane or cover which is bonded to a foam 
region at any common boundary therewith by the material of which that foam 
region is made. The plurality of foam regions include at least one foam 
region made of a material which, when creamed, risen and cured, provides a 
foam region having a greater density, hardness or resistance to 
compressibility than at least one other foam region so that one foam 
region is relatively "hard" and the other foam region is relatively 
"soft". Typically, the cushion, when finished, comprises an upper or front 
side defined by a portion of the flexible membrane, and the relatively 
soft foam region is disposed at the upper or front side of the cushion 
between the membrane and the relatively hard foam region of the foam 
article. However, a reverse arrangement is possible, as where the cushion, 
when finished, comprises an upper or front side defined by a portion of 
the flexible membrane, and the relatively hard foam region of the foam 
article is disposed at the upper or front side of the cushion between the 
membrane and the relatively soft foam region of the foam article. 
Furthermore, a cushion in accordance with the invention can embody a foam 
article having more than two foam regions of different hardness and these 
regions can be disposed in various arrangements with respect to one 
another and with respect to said membrane. 
In each of the improved methods herein disclosed, there is provided a 
flexible outer membrane which becomes part of the cushion and which may be 
made of plastic, cloth, leather, similar materials, or combinations 
thereof. The flexible outer membrane is disposed so that it defines one or 
more membrane cavities into which liquid formulations, hereafter 
described, can be poured. The membrane can be pre-formed to and maintained 
in a desired shape or contour, or disposed in a mold cavity in a mold 
which maintains it in a desired shape or contour. Then, a plurality of 
formulations in liquid form, each of which will ultimately yield a foam 
region of a desired density or hardness, are poured in some predetermined 
sequence into the cavity or cavities in the membrane. When all 
formulations have been poured, allowed to cream and rise to a desired 
extent, they are then allowed to cure and in doing so bond together at 
common boundaries between foam regions and also at common boundaries 
between a foam region and the membrane. 
In those methods wherein the membrane is disposed in the mold, either 
gravity alone can be relied on to cause the membrane to assume the contour 
of the mold cavity, or the membrane may be forcibly fitted therein 
(manually or by a die) or the space between the membrane and walls of the 
mold cavity can be subjected to low air pressure (vacuum) to positively 
cause the membrane to assume the contour of the mold cavity, assuming that 
the membrane porosity is selected to permit this. 
Furthermore, the orientation of the membrane cavity may be changed before, 
while, or after a particular formulation is poured into the membrane 
cavity to thus control the flow of any or all of the formulations and 
thereby determine the location and/or shape of the foam regions in the 
finished cushion. 
If a pre-formed membrane is not disposed in a mold when a liquid 
formulation is poured thereinto, the flexible membrane must be fabricated 
of substantially liquid impervious material to prevent leakage of the 
liquid formulation therethrough before it cures. 
If the membrane is disposed in a mold and low air pressure (vacuum) is 
relied on to maintain it in conformity with the mold cavity shape, then 
the membrane must be fabricated of material which is sufficiently fluid 
impervious to prevent leakage and to enable the membrane to conform to the 
mold cavity shape or contour under low pressure conditions. 
The improved cushions and improved methods offer numerous advantages over 
the prior art. For example, in the cushion, each foam region in the foam 
member is bonded at any common boundary with another foam region and is 
also bonded to any common boundary it may have with the flexible membrane. 
The bonds employ the same material of which a foam region is made. 
Therefore, no separate adhesives need be employed or applied to join foam 
regions together or to join them to the membrane. Thus, the finished 
cushion is a strong, coherent, integral product, Furthermore, numerous 
costly manufacturing steps employed to manufacture prior art cushions, 
such as fitting and gluing foam blocks and covers, are eliminated. 
Customized cushions are easy to provide because the various foam regions 
can be disposed as desired relative to the flexible membrane and in any 
desired order or arrangement. Changing the orientation of the cavity as 
formulations are poured, or while one or more formulations is still in a 
flowable state, enables shaping and positioning of one or more foam 
regions to suit the requirements of a particular cushion. 
Other objects and advantages of the invention will hereinafter appear.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Cushions 
FIG. 1 is a perspective view of a finished cushion 10 in accordance with 
the invention which, for example, could be used as a seat cushion or a 
backrest cushion, depending on its orientation, but is shown disposed as a 
seat cushion so as to present an upper side 12, a front side 13, a rear 
side 14, a pair of opposite lateral sides 15 and 16, and a bottom side 17. 
Upper side 12 of seat cushion 10 would correspond to a front side 12, if 
cushion 10 were used a backrest cushion. 
The cross-section view in FIG. 2 shows that cushion 10 comprises an outer 
cover in the form of a flexible membrane 20 and a foam article 22 disposed 
within and bonded, as at 24, to the flexible membrane. Flexible membrane 
20 may take the form of a sheet of plastic, cloth fabric, cloth coated 
with plastic, leather, combinations of these materials, or the like. Foam 
article 20 comprises a plurality of foam regions 26 and 28 of different 
foam density, hardness or compressibility. The foam regions 26 and 28 are 
bonded together at any common boundary therebetween, as at boundary 30, by 
the materials of which the foam regions are made. Each of the foam regions 
26 and 28 is bonded at any common boundary, such as boundary 24, between 
each foam region and flexible membrane 20 by the material of which that 
foam region is made. Foam region 26 is understood to be relatively hard 
and foam region 28 is understood to be relatively soft. 
FIG. 3 is a top plan view of cushion 10 shown in FIGS. 1 and 2 and shows, 
for example, a typical position of soft foam region 28, i.e., at the 
middle of the upper side 12 of cushion 10 between two dashed boundary 
lines 30. 
FIG. 4 is a cross-section view of another cushion 10A wherein a foam region 
28A underlying substantially all of membrane 20 is soft and the two spaced 
apart foam regions 26A near the lateral sides of the cushion are hard. 
FIG. 5 is a cross-section view of another cushion 10B wherein two spaced 
apart foam regions 28B underlying membrane 20 at the upper side of the 
cushion are soft and wherein an underlying foam region 26B is hard. FIG. 6 
is a top plan view of cushion 10B and shows, for example, typical 
positioning of the two spaced apart soft regions 28B at the upper side of 
cushion 10B, i.e., each region 28B between a pair of dashed boundary lines 
40. FIGS. 16, 22 and 23 show other cushions designated 10C, 10D and 10E, 
respectively. 
As will be understood, a cushion in accordance with the invention could 
embody any desired arrangement of discrete hard and soft foam regions. 
Furthermore, a cushion could embody more than two foam regions which 
differ from one another as regards relative foam density, hardness or 
compressibility. 
Method 
The general method of making a cushion comprising a flexible membrane or 
cover and a foam article having foam regions of different foam density, 
hardness or compressibility bonded to the membrane, comprises the steps 
of: 
(a) providing a flexible membrane having a membrane cavity therein; 
(b) adding to the membrane cavity in a predetermined sequence a plurality 
of formulations in liquid form which, when completely foamed and cured, 
provide a foam article having foam regions of different density, hardness 
or compressibility; 
(c) allowing each liquid formulation to cream, foam and rise to a desired 
extent before or during pouring of a subsequent formulation; 
(d) and allowing the formulations to cure and bond together at any common 
boundary between formulations, and bond together at any common boundary 
between a formulation and the membrane. 
It is preferred, as shown in FIG. 17, that flexible membrane 20 be disposed 
in a mold 50 and conformed to the shape of the mold cavity 52 so that the 
membrane defines a membrane cavity 54 which is adapted to receive the 
formulations which are poured thereinto to form a foam article such as 22. 
Membrane 20 can be conformed to the shape of mold cavity 52 by gravity, or 
manually or by a die, or, as shown in FIG. 18, by evacuation of air from 
the space 56 between membrane 20 and mold cavity 52 by means of a vacuum 
pump 58 connected to space 56. 
However, it is within the scope of the present invention to use a flexible 
membrane 20 which is pre-formed, or secured in such a manner, as to define 
one or more membrane cavities 54 and which does not require a mold 50 for 
cavity definition and/or membrane support. 
All methods disclosed herein require the use of at least two formulations 
that can be of the type disclosed in detail in U.S. Pat. Nos. 4,405,681 
and 4,190,697, hereinbefore referred to. For purposes of the following 
discussion, it is sufficient to note that each of the plurality of 
formulations used in the present invention has the following properties: 
1. initially it is in a liquid form or state; 
2. it has a predetermined known specific gravity when liquid; 
3. it starts to cream and rise upon being poured into membrane cavity 54 
and in that condition has a lower specific gravity than when in its liquid 
state; 
4. it becomes fully expanded and cured; 
5. it is adhesive or "tacky" while creaming and rising and before it is 
cured, and will adhere to any contiguous formulation in the same state and 
will adhere to any contiguous membrane surface; 
6. it provides, when cured, a foam region which has a predetermined foam 
density, hardness or compressibility (which can be characterized as 
relatively hard or soft), as compared to the foam regions formed by the 
other formulations; 
7. it is mechanically bonded, when cured, to any contiguous foam region or 
contiguous membrane surface. 
The cushion 10 shown in FIGS. 1, 2 and 3 can be made by a method depicted 
in FIGS. 7-11. A cushion 10E (FIG. 16) can be made by another method 
depicted in FIGS. 12-16. Both methods presuppose the use of one 
formulation which produces a "hard" foam region 26 and another formulation 
which produces a "soft" foam region 28. 
Referring to the first method depicted in FIGS. 7 through 11, assume that 
flexible membrane 20 is disposed (in mold 50 or otherwise) so as to 
provide a membrane cavity 54. The formulation which will provide a hard 
foam region is poured as a liquid into cavity 54 to some level S (FIG. 7) 
and allowed to partially cream and rise to some level T (FIG. 8). 
Referring to FIG. 9, then, the other formulation which will provide a soft 
foam region is poured in liquid form into cavity 54 and, because its 
specific gravity as liquid is greater than that of the partially creamed 
first-poured formulation, it passes therethrough to the bottom of cavity 
54, filling to some level R, and the partially creamed first formulation 
floats thereon. Referring to FIG. 10, the second-poured formulation is 
allowed to cream and rise. After sufficient time has elapsed, both 
formulations have risen fully, are cured, and are bonded together at their 
common interface 30 and are also bonded to membrane 20 at 24 at any 
interface therewith. Referring to FIG. 11, the finished cushion 10 (after 
removal from mold 50, if used) is inverted and seen to comprise membrane 
20, soft foam region 28 at the top of cushion 10 and hard foam region 26 
therebelow. 
It is to be understood that cushion 10B, which may be a seat designed for 
use by two persons, shown in FIGS. 5 and 6, is made in a manner similar to 
that described immediately above. However, in the case of cushion 10B, the 
liquid which will form the two spaced apart soft regions 28B is poured 
into cavity 54 at two spaced apart locations after the first-poured liquid 
has partially creamed and risen. 
It is to be understood that cushion 10A, shown in FIG. 4, is made in a 
manner similar to that above described. However, in the case of cushion 
10A, the liquid which will form the two spaced apart hard regions 26A is 
poured into cavity 54 at two spaced apart locations as the first-poured 
liquid. 
The second method depicted in FIGS. 12 through 16 for making cushion 10C 
will now be described. Referring to FIG. 12, assume that flexible membrane 
20 is disposed (in mold 50 or otherwise) so as to provide a membrane 
cavity 54. Then, a formulation which will provide a soft foam region is 
poured in liquid form into cavity 54 to a level A and allowed to cream and 
rise to some level B (FIG. 13) and partially cure. Referring to FIG. 14, 
another formulation which will provide a hard foam region is poured in 
liquid form into cavity 54 to some level C. Since the second pour cannot 
pass through the partially cured first pour, the second pour will float on 
the partially cured first pour and is allowed to cream and rise to some 
level D (FIG. 15). Referring to FIG. 15, both formulations are allowed to 
rise fully and to cure fully. After fully curing the two foam regions bond 
together at their common interface 30 and to membrane 20 at 24. Referring 
to FIG. 16, the finished cushion 10C (after removal from mold 50, if used) 
is inverted and seen to comprise membrane 20, soft foam region 28 at the 
top of cushion 10 and hard foam region 26 therebelow, not necessarily 
limited to the full width of the cushion. 
Referring to FIGS. 19 through 23, methods will now be described which 
involve changing the orientation of membrane cavity 54 while one or more 
formulations in the membrane cavity 54 is still in a flowable state (i.e., 
still liquid or partially creamed) and maintaining a chosen orientation 
until the flowable state changes to a non-flowable state, as when 
partially cured, to thereby control or determine the shape of the entire 
foam member or the shape and/or location of one or more of the foamed 
regions in the foam member relative to other regions or relative to the 
membrane. 
To make a cushion such as 10D, shown in FIG. 22, which comprises a flexible 
membrane 20 and a foam member comprising a soft upper foam region 28D and 
a hard lower foam region 26D which slopes upwardly toward the front side 
17D of cushion 10D, the steps are as follows. 
As FIG. 19 shows, membrane 20 is disposed in mold 50 so that its membrane 
cavity 54 has a certain orientation. Then, a formulation which will 
provide a soft foam region 28D is poured as a liquid into membrane cavity 
54. Either prior to, during or shortly after such pouring, while the 
formulation is still flowable, membrane 20 is tilted (as by tilting mold 
50) so as to change the orientation of membrane cavity 54 to that shown in 
FIG. 20, for example, and so that the formulation assumes the position 
relative to the membrane 20 shown in FIG. 20. It is to be understood in 
this example that the numeral 13D in FIGS. 19-22 designates what will be 
the front side of cushion 10D. The first formulation is allowed to cream 
and rise while the membrane cavity 54 is in the position shown in FIG. 20 
and is allowed to cure to the extent that the next formulation poured in 
cavity 54 will not penetrate the first pour. Then, the orientation of 
cavity 54 is returned, for example, to that shown in FIG. 21, and the 
second formulation is poured into cavity 54 and allowed to cream, rise and 
cure. When both formulations are fully cured, the cushion 10D is removed 
from mold 50 and inverted, as shown in FIG. 22. 
It will be apparent from the immediately preceding description that the 
pouring sequence, except for twice changing the orientation of membrane 
cavity 54, is the same as that generally described hereinbefore in 
connection with FIGS. 12-16. 
It is to be understood that the cavity 54 orientation sequence shown in 
FIGS. 19-21 could also be employed with the pouring sequence described in 
connection with FIGS. 7-11, provided that the cavity 54 is maintained in 
the orientation shown in FIG. 20 until both formulations cream, rise and 
cure. In such cases, a cushion 10E would have a longitudinal cross-section 
such as shown in FIG. 23. 
It is possible to dispose the cavity 54 in any fixed orientation before the 
formulations are poured and to maintain it in that orientation during 
creaming, rising and curing. This will provide positioning of the foam 
regions and to shorten pour time.