Note: Descriptions are shown in the official language in which they were submitted.
Coil Spring Mattress Construction
FIELD OF THE INVENTION
The present invention is directed to pocket coil mattresses and in particular
to
improvements with respect to a perimeter support region and a main sleep area
of the
mattress.
BACKGROUND OF THE INVENTION
Pocket coil mattresses are known for having extremely appealing flex
properties and
the ability to resiliently conform to different users thereby providing a
better night's
sleep. These mattresses have individual coil springs maintained in a
compressed
state in their own fabric pocket. Typically the fabric pockets are sewn in
long strips
and secured to form the mattress core.
Many pocket coil mattresses include either an edge wire around the mattress
that
connects to edge coil springs and provides additional stiffness for seating at
the edge
of the mattress or; a hard compression foam encasement to replace the
edgewire, as
well as between 25% and 33% of the spring core itself to prove a strengthened
seating edge. The edge wire although helpful in providing this additional
support, is
not desirable in that the mattress can be permanently damaged if subjected to
significant bending. Bending of a mattress is often necessary to allow passage
of the
mattress through a restricted access such as a narrow staircase or other
restriction.
Furthermore bending of the mattress is desirable for adjustable position
leisure beds
or hospital type beds. In the case of a foam encased seating edge, the end
result does
allow bending and does not have the sustainable performance and long term
recovery level as an complete spring edge with the attached edgewire. A foam
encasement seating edge is not a design that is applicable to the present
invention of
pocket coil spring core assembly.
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In our earlier patent US 6,295,676, a pocket coil mattress is disclosed that
does not
include an edge wire. This mattress allows bending of the mattress, however
the
edge of the mattress is substantially compressed when a user sits on the edge
of the
mattress. The ability to provide firm edge support and desirable flex for
sleeping is
challenging.
The present invention provides an improved pocket coil mattress that allows
for the
bending thereof while providing substantially improved edge support and
without
impacting on the uniform comfort of the balance of the mattress spring
underlying
its sleep surface when fully finished with upholstery padding material. These
advantages are realized while still providing a main sleep area and perimeter
support region that has the comfort advantages that is now expected with a
pocket
coil mattress.
SUMMARY OF THE INVENTION
A mattress according to the present invention, comprises a main sleep area
surrounded by a perimeter support region. The main sleep area and the
perimeter
support region are defined by wire coil springs contained within individual
fabric
pockets. The wire coil springs in the main sleep area are arranged in a
honeycomb
offset series of rows. The wire coil springs in the perimeter support region
are of a
different wire construction and have different flex characteristics from the
wire coil
springs in the main sleep area. The wire coil springs in the perimeter support
region
are arranged in side by side rows and thus define a non-honeycomb arrangement.
The perimeter support region has at least two side by side rows about the
mattress.
The perimeter support region includes four corner configurations that each
have at
least eight cross connected wire coil springs. These coil springs are cross
connected
to join coil springs of the same row and opposite rows. Between the corner
configurations wire coil springs of the perimeter region are only connected
across
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rows. The mattress is made without an edge wire about the perimeter of the
mattress. The coil springs of the perimeter region cooperate to accommodate
substantial resilient bending of the mattress in a length thereof while
providing
improved support for side seating.
According to an aspect of the invention, the wire coil springs of the
perimeter
support region are of a smaller coil diameter relative to the diameter of the
wire coil
springs of the main sleep area.
According to a further aspect of the invention, the wire coil springs of the
perimeter
region have a gauge of about 14.5.
In a further aspect of the invention, the wire coil springs of the main sleep
area are of
a gauge of about 15.5.
According to a preferred aspect of the invention, the wire coil springs of the
perimeter support region are of a diameter of about 2 inches at the ends
thereof and
the springs taper inwardly to a narrow waist of about 50 millimeters.
In a further aspect of the invention, the perimeter support region includes at
least
three rows of wire coil springs of a gauge between 14 and 15.
In yet a further aspect of the invention, the perimeter support region at the
top
surface thereof, is connected by a flexible high-strength plastic mesh
extending over
the mattress. Preferably the bottom surface of the mattress is also connected
a
flexible high strength plastic mesh.
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BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are shown in the drawings wherein:
Figure 1 is a perspective view of the new mattress showing resilient
deformation of a
corner region of the mattress;
Figure 2 is a perspective view of the mattress showing bending of the mattress
to
accommodate variable position beds;
Figure 3 is a perspective view of the mattress showing bending thereof about a
midpoint of the mattress;
Figure 4 is a partial perspective view of the corner configuration of the
mattress;
Figure 5 is a top view showing a number of individual components the mattress;
Figure 6 is a partial top you showing the wire coil springs of the perimeter
region
and the wire coil springs of the main sleep area;
Figure 7 is a partial perspective view of coil springs preloaded and
maintained in
their own individual fabric pocket:
Figure 8 is a partial top view of the twin mattress having two rows of wire
coil
springs defining the perimeter support region;
Figure 9 is a partial perspective view of a prior art mattress showing
resilient
deformation of the edge of the mattress when a person sits thereon;
Figure 10 shows the improved perimeter support region of the present invention
with a person sitting thereon;
Figure 11 is a partial perspective view showing details of the perimeter
support
region and main sleep area;
Figure 12 is a partial perspective view similar to figure 11 showing our prior
art
arrangement;
Figure 13 is a perspective view of the new coil spring used in the perimeter
support
region;
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Figure 14 is a side view of the new coil spring of Figure 11 showing the
narrow
waist;
Figure 15 is a side view of the coil spring used in the main sleep region
illustrating
the barrel shape profile thereof;
Figure 16 is a side view of the coil spring used in the main sleep area in an
initial
uncompressed state and transitioning to the preloaded state maintained in the
fabric
pocket as shown on the right-hand side;
Figure 17 is a side view showing the different preloaded compressed states of
the
coil springs of the perimeter support region and the main sleep area;
Figure 17a is a sectional view showing the gauge of the wire coil spring of
the
perimeter support region;
Figure 17b is a sectional view showing the gauge of the wire coil spring of
the main
sleep area;
Figure 18 is a side view showing the spring of the border region relative to
the main
sleep area
Figure 19 is a partial perspective view of a corner configuration of the
mattress with
the fabric cover mattress secured above; and
Figures 20 and 21 are partial side views of same coil spring shown enclosed
into
different types of fabric pocket.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figures 1 through 3 in the application, illustrate various bent configurations
of the
mattress that commonly occur. In figure 1, one of the corners of the mattress
has
been bent upwardly. In figure 2, one end of the mattress has been raised as
may be
necessary for hospital beds or variable leisure beds that are moveable to a
sitting
configuration. This type of bending of the mattress intermediate its length,
is now a
common requirement. The bending of the mattress into the 'U' configuration of
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figure 3, may be necessary to move the mattress through a restricted space
such as a
narrow stairwell. In recent years, larger mattresses are more popular and
access to
the bedroom may be limited or restricted. Having a pocket coil mattress
without a
perimeter edge wire, provides this flexibility and easily accommodates varying
the
components of the mattress that may be required for different models.
Our earlier United States Patent 6,295,676 discloses a pocket coil mattress
that does
not include an edge wire and as such the mattress can bend intermediate its
length.
Although this structure has many advantages over existing mattresses, it has
some
disadvantages with respect to edge seat support. In pocket coil mattresses,
the
ability of the mattress to independently respond to the movement of two users
and
allow for significant isolation of these movements, is a primary advantage.
The
perimeter support region of the mattress includes two or more rows of coil
springs
that have different flex characteristics relative to the coil springs of the
interior main
sleep area. The border springs intermediate the corners, although stiffer than
the coil
spring of the main sleep area, still deform significantly and seating support
on an
edge mattress causes unwanted sidewall distortion as shown in the prior art
mattress of Figure 9. The present invention provides a structure, where these
disadvantages are overcome.
The mattress 2 as shown in figure 4, includes a mattress core 6 having a
perimeter
support region 10 about the main sleep area 50 of the mattress. The perimeter
region
10 includes an outer row 12 of pocket coil springs, a middle row 14 of pocket
coil
springs and in the mattress of Figure 4, an inner row 16 of pocket coil
springs. The
main sleep area 50 has the coil springs thereof arranged in a honeycomb
pattern.
Pocket coil springs of the main sleep area are of a lighter gauge wire and are
more
compressible than coil springs of the perimeter support region 10.
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The perimeter support region 10 includes four corner configurations 30 and in
the
case of a queen or king mattress, each corner configuration is defined by 15
connected pocket coil springs. Each of these pocket coil springs are
mechanically
connected to adjacent pocket coil springs as indicated by the mechanical
connectors
32. These mechanical connections are preferably upholstery stables located at
the
point of contact between adjacent pocket coil springs. With this arrangement a
linked series of pocket coil springs is provided in each corner of the
mattress. These
connected coil springs are in contrast to the coil springs of the main sleep
area that
are independent. The mattress 2, with the four corner configurations 30,
provide a
more rigid configuration supporting the coil springs of the perimeter support
region
10 between corner configurations.
The coil springs, between two corner configurations of the perimeter support
region,
are merely connected to adjacent pocket coil springs of the respective row or
rows.
As can be appreciated these connected coil spring do not move independently
due to
the common mechanical connection 32 but have more independent movement than
the coil springs of the corner configurations.
The corner configuration 30, as shown in Figure 4, provides an integrated
support
structure at each corner of the mattress that act to stabilize other pocket
coil springs
of the perimeter support region 10 as well as the coil springs of the main
sleep area
50. The stable corner configurations 30 and the individual coils of the
mattress 2 are
connected by an upper high strength plastic mesh 60 and a lower high strength
plastic mesh 62. In addition to the various mechanical connections of the
coils to
each other shown at the upper surface or top of the coils springs, the coil
springs are
also preferably connected in a similar manner on the lower surface of the
mattress.
These connections pass through the fabric pockets 36.
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Figure 5 shows a queen-size mattress having the perimeter support region 10
surrounding the main sleep area 50. The spring coils of the main sleep area
50, laid
out in a honeycomb configuration in contrast to the spring coils of the
perimeter
support region 10 that are positioned in a side by side configuration. Only a
portion
.. of the upper plastic grid mesh 60 is shown in the lower left corner of
figure 5, and
locates the corner configuration shown in greater detail in figure 6. For
better
understanding, the fabric pockets 36 of the coil springs are only partially
shown.
The corner configuration 30 of figure 6 (corresponding to a queen or king size
mattress) includes the first four coil springs in each of the three rows of
coil springs
in both the length and the width of the mattress and are mechanically secured.
The
mechanical fasteners 32 connect t each coil spring to its abutting adjacent
coil
springs. Some of the coil springs include four mechanical connection points.
The
corner configuration 30 includes the first four coil springs in each of the
rows of the
perimeter support region 10 in both the length and width direction. The coil
springs
of the perimeter region 10 located between corner configurations, only include
mechanical connections 32 that join the coil springs in adjacent rows not
along a row.
The top and bottom high strength plastic mesh 60 and 62 connect the spring
coils of
the perimeter support region as well as the spring coils of the main sleep
area 50.
These corner configurations in combination with the high strength mesh, anchor
and
secure the remaining coil springs of the perimeter support region between the
corner
configurations. Each of the wire coil springs of the perimeter support region,
is of a
reduced overall diameter relative to the diameter of the wire coil springs of
the main
sleep area 50. Furthermore, the coil springs in the main sleep area 50, are in
the
honeycomb configuration and provide independent movement while also
supporting each other as the coil springs are closely packed.
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Figure 7 shows an example of wire coil springs located within their connected
fabric
pockets 36. The pockets are of a fixed length and maintain the wire coil
springs in a
partially compressed or preloaded state.
Figure 8 shows part of a twin size mattress with a reduced perimeter support
region
having only two rows of wire coil springs surrounding the main sleep area 50.
In
this case the first three coil springs of the corner configuration 30 in each
direction,
are mechanically connected by fasteners 32.
10 One of the problems associated with pocketed coil spring design
mattresses, is that
a person sitting on a side portion of a prior art mattress, as shown in figure
9, creates
significant compression and distortion of the side wall 42 of the mattress as
indicated
by outward distortion of the sidewall of the mattress and distortion ripples
54.
A mattress with the new comer configuration having the improved coil wire
springs
in the perimeter support region, undergoes less compression and less sidewall
outward distortion and therefore fewer distortion ripples occur as the
perimeter
support region is stiffer. With this improvement there is still some
distortion of the
side wall of the mattress as evident at 56, however the distortion is limited
and
improved seat support is provided. Furthermore although the perimeter support
region has been stiffened, the desirable sleeping comfort of the mattress is
maintained.
Figures 11 and 12 provide a comparison of new pocket coil spring mattress
shown in
figure 11 and the prior art pocket coil spring mattress as shown in figure 12.
For a
better understanding, the filler springs 28 are shown in an uncompressed state
and
are of a length of 10 inches indicated at 53. The end diameter indicated by 57
is 2
inches. The spring is barrel shaped with a waist of 55mm. In contrast the
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uncompressed state of the prior art filler spring 28a is 9.5 inches indicated
at 55, the
end diameter 59 is 2.25 inches and the waist of the barrel shape is 58mm.
Improvements with respect to the flex and shape of the wire coil springs and
the
relationship of the wire coil springs of the perimeter support region to the
coil
springs of the main area 50, can be appreciated from a review of figures 13
through
15. The heavier gauge wire of the coil springs in the perimeter support region
has a
tensile strength in the range 240,000 to 280,000 psi whereas the wire of the
lighter
gauge coil springs of the main sleep area has a tensile strength in the range
of
290,000 to 310,000 psi.
Wire coil spring 24 of the perimeter region, is preferably of a gauge of 14.5.
The
height of the spring before compression is approximately 10 to 10.5 inches and
the
spring end diameter is 2 1/8 inches. The number of turns of the spring is six.
As
shown in figure 14, the spring is formed to taper inwardly to a reduced waist
having
a diameter of approximately 50 mm in the preferred embodiment. The perimeter
support springs are compressed from the uncompressed state and received in a
pocket that accommodates a spring length of about 6 1/2 inches. Our prior art
spring
used at the sides of the mattress, has a barrel type shape that tends to
distort
outwardly when compressed. In addition, the uncompressed state of the spring
was
9 to 9.5 inches. The tapered waist of the new spring reduces outward
distortion
during substantial compression that may occurs when a person sits on the side
edge
of the mattress and also has higher support load due to the increased
compression
due to its longer uncompressed length. The load lift capability of the spring
has been
increased without changing the overall length, gauge or strength of the wire.
In this
way, the load lift capability has been increased while still maintaining
uniform
comfort balance across the finished mattress.
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The new mattress with the perimeter support region of the revised shape and
stronger coil springs, provides improved seat support between the anchoring
corners. The improved load carrying capabilities of each spring is provided by
reducing the diameter of the spring and changing the shape of the spring from
a
barrel shape to a tapered waist design. The length of the perimeter support
region
springs has been increased (preferably from 9.5 inches to 10.5) and the
preload of
each spring has increased and is in the range of 900 to 1000 grams whereas the
prior
art coil spring typically had a preload in the range of 750 to 780 grams. The
diameter
of the prior art spring was about 2.5 inches and the center waist diameter was
57
mm. The wire length of about 47 inches was maintained. Therefore the wire coil
spring 24 has been redesigned to provide additional support in a side region
of the
mattress that is prone to user distortion due to a concentrated load created
by sitting
on a side or end of the mattress. The enhanced load carrying capabilities of
the
modified spring and the stiffer corner configurations cooperate and reduce
sidewall
distortion while maintaining independent sleep support in the main sleep area
of the
mattress as well as compatible sleep support in the perimeter support region.
Also
side seating on the mattress is improved as there is less compression.
The filler springs in the sleep central area preferably are also been modified
to
increase the length of the uncompressed spring to about 10 inches whereas our
prior
filler spring was of a length of 9 to 9.5 inches. The diameter of the spring
is now
preferably 2 inches whereas previously it was about 2.25 inches. The waist of
its
barrel shape is now 55mm compared to the previous 58mm. Both the new and old
springs are 6 turn springs of the same 15.5 gauge that are pre-compressed and
maintained in a 6.5 inch pocket. The preload of the filler spring has
increased to 490
to 500 grams compared to the previous preload of about 430 grams. The changes
to
the filler spring cooperate with the new perimeter support region spring to
provide
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an effective transition at the junction of the sleep central area and the
perimeter
support region.
Diameters of both edge (border) coil and sleep central area (filler) coil,
despite the
difference in wire gauge are close in size so as not to distort the final
assembled core
in terms of resilient performance and responsive compliance across the core
surface
that translates above and below in the finished mattress. This describes
desirable,
uniform performance and compliance across the finished (upholstered and
covered)
mattress from side to side and head to foot. The springs cooperate to provide
a
proportional balance between the perimeter edge and the sleep central
subassemblies placed in the final pocket spring core assembly.
Surprisingly, the additional pre-compression and changes to the perimeter coil
springs, support the load of a person sitting on the side of the mattress with
less
compression of the mattress sidewall. These changes in combination with the
increased load carrying capability of the main sleep area springs per unit of
compression, provides a pocket coil mattress with the known desired sensation
of
pressure relief, great support and fast response to the user's movement. The
modified perimeter and main sleep area springs have greater load carrying
capability per unit of compression while still providing the desired response
and
without a load ridge at the junction of the perimeter support springs and the
main
sleep area springs. Both types of springs have a higher rate of recovery
without
impacting the user's perception of great support and appropriate response to
user
movement.
The extent of side edge compression of the mattress due to a user sitting
thereon, has
substantially decreased from 3 to 4 inches for example to preferably 1 to 2.5
inches.
This change provides the additional support and allows the mattress able to
meet the
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need of various bed applications without using a border edge wire. Furthermore
the
springs are less likely to fatigue over the life of the mattress due to the
higher
strength.
Figure 16 illustrates one of the filler springs 28 undergoing compression and
being
retained in the fabric pocket 36 in a compressed state to preload the spring.
The
individual fabric pockets 36 are of the appropriate size to maintain the
desired initial
compression of the springs. Although the fabric pocket is shown with spring 28
a
similar pocket arrangement is used to maintain the initial compression of
perimeter
springs 26.
Figure 17 shows the assembled core of the mattress 2 together with top and
bottom
upholstery type cushioning material 93 that may vary between different
mattress
models. A fabric outer material would be present to finish the mattress. Other
intermediary layers may also be present as found in existing pocket coil
mattresses.
Figure 18 shows some movement of the coil spring when a weight is applied to
the
edge of the mattress. Figure 19 shows additional layers of the mattress 2
supported
by the pocketed coil spring core 6. These various layers are preferably
secured by
tufting.
Figures 20 and 21 show the wire coil springs 28 received in pockets of
different types
of material 36a and 36b. The material of the pocket may vary depending upon
the
particular characteristics of the mattress. Some pocket material is thicker
(pocket
material 36b) than other pocket material (pocket material 36a) as exemplified
in these
figures. Somewhat surprisingly the number of coils provided in the length or
width
of the mattress may vary depending upon a change in the thickness of the
pocket
material.
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The applicant has found, that improvements to pocket coil mattresses can be
realized
by providing additional support created by the connected corner
configurations.
Further improvements in the characteristics of the side edge of the mattress
can be
.. realized by changing the shape and load carrying capacity of the wire coil
springs
used in the perimeter support region. Further improvements can be realized by
utilizing wire coil springs in the main sleep region that are of reduced
diameter and
of greater load carrying capabilities relative to the prior art mattresses.
.. Although the invention has been described herein in detail appreciated the
variations may be made thereto without departing from the attached claims. The
detailed description has focused on applicant's preferred embodiments however
the
attached claims define the applicant's invention.
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