Note: Descriptions are shown in the official language in which they were submitted.
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FILLING MATERIAL FOR CUSHIONS
This invention relates to filling materials packed or blown into fabric
enclosures to form cushions, upholstered cushioning, comforters, and pillow
cores.
Background of the Invention
Conventional pillows are usually filled with a cushioning filler material
of cotton wadding or batting, feathers, down, sponge rubber, fiber fill or
foam.
Among these materials, down shows excellent properties in bulkiness, softness,
thermal insulation, compression recovery and moisture transmission. Many
people,
however, are allergic to down, and down may harbor not only allergens, but
also
insects and bacteria. Down is also cost prohibitive for many applications.
Cotton, compared with down, has inferior bulkiness, softness and
thermal insulation. Its compression recovery is not as good as down or some of
the
synthetic filling materials. When damp, the cotton wads together and does not
sufficiently recover to its uncompressed state.
The synthetic materials have advantages over the natural materials, in
view of cost, durability and health concerns. Polyester fiber fill is an
especially
popular filling material. Other synthetic fibers used as fillers include
polyethylene,
polypropylene, polyamide and aramides. A matrix of straight fibers is pre-
fluffed
with a picker apparatus to separate the fibers to permit their insertion into
a cushion or
pillow casing. The fibers are then blown through an injector or plurality of
injectors
into cavities formed in the casing. With cushion use, fibers tend to bunch up
and
create pockets which permit the cushion or pillow to "bottom out".
Particularly, it has
been found that fibers nest and clump together when blown into larger volume
casings
or casings with complicated shapes. Thus, in an effort to prevent undue
clumping of
fibers, larger or more complicated cushions are separated by ticking into
several
smaller compartments that are filled with the fibers.
To eliminate some of the crushing and clumping associated with
straight fiber filling materials, U.S. Patent 3,922,756 proposes forming the
fibers into
a filamentary spherical body. Spherically intertwined fiber aggregates also
are shown
in U.S. Patents 4,998,309 and 4,794,038.
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In lieu of fiber fill, blocks of sponge rubber or foam may be shredded
into chunks or particles that are used as filling materials for cushions and
pillows.
The edges of the shredded foam chunks tend to hook together, which creates
regions
with more foam and regions with less foam within the cushion core. The foam
chunks
or particles do not reproduce the cushioning plushness of fiber fill or down.
To address the clumping problems associated with fibers, U.S. Patent
5,061,737 suggests combining fiber fill (1-3 inch long fibers) with shredded
polyurethane foam chips (1/4 inch blocks) to form a filling material. The
fibers are
coated or slickened with a silicone finish prior to mixing with the shredded
foam. The
patent states that the length and diameter of the fibers relative to the size
of the foam
chips and the limited movement permitted by the slickened fiber surfaces
affords
adequate cushioning support while still maintaining the cushion shape.
U.S. Patent 4,l09,332 proposes using polyurethane foam cut into
polygonal shaped rods. The rods have flat planar top, bottom and side
surfaces, and
preferably have a length and width proportionally greater than the rod
thickness (or
height). The patent emphasizes the importance of the planar nature of the side
areas
to prevent the rods from hooking on to one another when used as a filling for
cushions.
Other synthetic filling materials include engineered elastomeric
spheres, U.S. Patents 4,754,5l 1 and 5,608,936, pebbles or beads, U.S. Patents
3,608,961 and 3,999,801, or tubular hollow forms.
To date the prior art has not shown cellular polymer or foam filling
materials that can be readily inserted by blowing or other means into the
chambers of
cushion, upholstery cushion and pillow casings without the need for additional
ticking
or compartments, that repeatedly recover from compression, that avoid clumping
and
nesting thereby preventing pockets and "bottoming out", and that may be made
economically as compared to prior filling materials.
Summary of the Invention
A filling element for a cushion, pillow, or upholstered article is formed
from a resilient material shaped into a bent strand. The strand preferably has
a portion
along its length that is Z-shaped, V-shaped, C-shaped or S-shaped. The
resilient
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material may be formed to have a combination of these shapes along different
portions of the strand length.
In the preferred embodiment, the strand has a substantially constant
cross-sectional thickness along its length. In a11 cases, the length of the
strand is
substantially greater than its nominal cross-sectional thickness. Preferably,
the length
of the strand is about 5 to 20 times greater than the nominal cross-sectional
thickness
of the strand. In addition, the individual sections making up the strand
length also
have a length greater than the nominal cross-sectional thickness of the
strand.
The strand is formed with at least one bend along its length.
Preferably, the bend is at an angle of between about 15 to about 120 degrees,
most
preferably about 30 to about 40 degrees.
The filling element may be formed from a strand with a Z-shape. In
this case, the strand has generally straight legs or leg sections depending at
bent
angles from a generally straight center section. The legs terminate at end
sections
with planar faces. The planar faces of the end sections may be cut at an angle
perpendicular to the sidewalk of the legs. Preferably, the planar faces of the
end
sections are cut at an angle other than perpendicular to the sidewalls of the
legs, such
that the faces each have a cross-sectional areas greater than the nominal
cross
sectional area of the corresponding leg.
The filling element may be formed from a strand with an S-shape. In
such case, the strand has generally curved legs depending at bent angles from
a
generally curved center section. The legs terminate at end sections with
planar faces.
The planar faces of the end sections may be cut at an angle perpendicular to
the
sidewalk of the legs. Preferably, the planar faces of the end sections are cut
at an
angle other than perpendicular to the sidewalk of the legs, such that the
faces each
have a cross-sectional areas greater than the nominal cross sectional area of
the
corresponding leg.
The resilient material is a cellular polymer material, preferably
polyether or polyester polyurethane foam. When a polyurethane foam is used,
the
foam has a density in the range of about 0.6 to about 1.2, preferably about
0.8 to about
1.0 pounds per cubic foot, and an indentation force deflection (IFD) in the
range of
about 4 to about 1 S, preferably about 8 to about 12 pounds per cubic foot.
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Description of the Figures
FIG. 1 is a schematic diagram showing a plurality of filling elements of
the invention as they are blown into a casing to form a cushion;
FIG. 2 is perspective view of a strip of resilient material prior to
cutting to a desired strand length;
FIG. 3 is a perspective view of a piece of resilient material of FIG. 2
cut to a desired strand length to form a filling element according to the
invention;
FIG. 4 is a perspective view of a strip of an alternate resilient material
prior to cutting to a desired strand length; and
FIG. S is a perspective view of a piece of resilient material of FIG. 4
cut to a desired strand length to form a filling element according to the
invention.
Description of the Preferred Embodiment
Cushions, pillows and upholstered articles may be formed by blowing
a filling material, such as polyester fiber fill into a casing. The filling
elements of the
present invention may be blown into cushion casings using the same blowing
apparatus used for fiber fill.
As shown in Figure 1, the apparatus 10 to fill a casing includes a
supply hopper 14, a blower 16 and an inserting pipe or tube 18. The filling
material
12, which is a plurality of the filling elements according to the invention,
is placed
into the supply hopper 14 and blown from the hopper 14 through the pipe 18 and
into
the casing 20 by blower 16. If not sewed together after it is filled, the
cushion casing
may be supplied with a zipper 22 or other fastening means.
A resilient material, such as polyurethane foam, is cut, such as by a
rotary cutter, or otherwise formed into a bent strand to form a filing element
according to the invention. As shown in Figure 2, the material may be formed
into a
long continuous strand 30 having a plurality of generally straight sections
interconnected together at their ends to form bent angles alternating upwardly
and
downwardly.
Individual filling elements are formed by cutting sections from the
long strand 30. Filling element 34 (shown in Figure 3) is formed by cutting
long
strand 30 at lines 32.
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The Z-shaped filling element 34 has a generally straight center section
36 with generally straight left leg section 38 and generally straight right
leg section 40
depending therefrom. The center section 36 and left leg section 38 form a bent
angle
42 therebetween. The center section 36 and right leg section 40 form a bent
angle 44
therebetween. Preferably, the angles formed between the center section 36 and
the leg
sections 38, 40 are in the range of about 15 to l20 degrees, most preferably
about 30
to 40 degrees. Although shown to be equivalent in Figure 3, the angle 42 may
be the
same as or different from the angle 44.
The left leg section 38 terminates at a planar face 46 with a rectangular
cross section on the left end of the filling element 34. The right leg section
40
terminates at a planar face 48 with a rectangular cross section on the right
end of the
filling element 34. As shown in Figure 2, the cut lines 32 are taken through
the strand
30 at points at which two generally straight sections meet at an angle. As a
consequence of these cuts, which are at oblique angles relative to the side
walls of the
generally straight sections, the planar faces 46, 48 have cross sectional
areas that are
greater than the nominal cross sectional area of the corresponding leg
sections 38, 40.
Had the cut lines been taken perpendicular to the sidewalk of a leg section,
the planar
faces at the ends of the filling element would have had cross sectional areas
equivalent
or nearly equivalent to the cross sectional area of the corresponding leg
sections.
The filling element 34 has a length, as measured from the farthest
extended portion of the left planar face 46 to the farthest extended portion
of the right
planar face 48, in the range of about 1.5 to 7 inches. Preferably, the length
of the
filling element does not exceed 5 inches. It has also been found that the
length should
be at least 2 inches to avoid many of the clumping and nesting problems
attributed to
shredded foam of the prior art. In the particularly preferred embodiment, the
center,
left leg and right leg sections are of substantially equal length. A
particularly
preferred section length is between about 1 to 2 inches, most particularly
1.25 inches.
Figures 4 and 5 relate to an alternate embodiment of the invention.
Figure 4 shows a long strand of resilient material 50 having a series of
alternating
upwardly curved sections and downwardly curved sections. The strand 50 is cut
at
cut line 52 to form filling element 54 shown in Figure 5.
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The S-shaped filling element 54 has a center section 56 disposed
between a left leg section 58 and right leg section 60. The place at which the
center
section 56 meets the left leg section 58 forms a downwardly bent angle 62. The
place
at which the center section 56 meets the right leg section 60 forms an
upwardly bent
angle 64. The left leg section 58 terminates at planar face 66, and the right
leg section
terminates at planar face 68. Planar faces 66, 68 have a generally circular or
oval
cross section. Depending upon the angle of the cut line 52 in relation to the
strand 50,
the planar faces 66, 68 may have a cross-sectional area the same as or greater
than that
of the nominal cross-sectional area of the corresponding leg sections.
The strands may be formed from any resilient material with generally
uniform properties. Cellular polymer materials, such as polyether or polyester
polyurethane foams, are preferred. Other materials include cross-linked
polyethylenes, polyolefins, and rebonded or recycled foams.
Cellular polyurethane structures typically are prepared by generating a
gas during polymerization of a liquid reaction mixture comprised of a
polyester or
polyether polyol, a polyisocyanate, a surfactant, catalysts, and one or more
blowing
agents. The gas causes foaming of the reaction mixture to form the cellular
structure.
Polyurethane foams with varying density and hardness may be formed.
Hardness is typically measured as IFD ("indentation force deflection") or CFD
("compression force deflection"). Tensile strength, tear strength, compression
set, air
permeability, moisture resistance, fatigue resistance, and energy absorbing
characteristics may also be varied, as can many other properties. Specific
foam
characteristics depend upon the selection of the starting materials, the
foaming process
and conditions, and sometimes on the subsequent processing.
The engineered shaped filling elements according to the invention do
not shift or form pockets when used as filling materials in cushion casings.
Unlike
fiber fill, the filling elements may be blown into a large cushion casing
without
segmenting the casing with ticking. The filling elements do not take on a
compression set, but rebound after being subjected to loads.
Per unit weight and per unit volume, the filling elements of the
invention offer cushioning properties greater than that provided by fiber
fill. When
cushions filled with equivalent volume amount of fiberfill and cushions filled
with the
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filling elements of the invention are subjected to equivalent dynamic and
static loads,
the cushions with the filling elements of the invention recover their height
more
completely and more rapidly than fiber-filled cushions. Load to half height
tests
confirm the filling materials of the present invention perform better than the
equivalent volume amount of fiber fill.
The invention has been illustrated by detailed description and examples
of the preferred embodiments. Various changes in form and detail will be
within the
skill of persons skilled in the art. Therefore, the invention must be measured
by the
claims and not by the description of the examples or the preferred
embodiments.
