Note: Descriptions are shown in the official language in which they were submitted.
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Resilient Unit and Method of Manufacture
The present invention relates to a resilient unit, and to a
method of making a resilient unit, and is concerned
particularly, but not exclusively, with a resilient unit
that can be used for example in an upholstered article such
as a mattress or similar.
Pocketed springs, otherwise known as encased springs, are
used in upholstered articles such as mattresses. Most
pocketed spring units comprise coil springs encased
individually in pockets of fabric material formed by
folding over a sheet of fabric to form two leaves that
envelope the springs, and then attaching the leaves
together between the springs so as to form a string of
springs. The strings are then joined to form an array of
springs as a pocketed spring unit. The joining of the
strings together to form an array is achieved either by
gluing the strings together along the cylindrical surfaces
of the pocketed springs, one string to the next, and so on
until the unit is formed, or else by arranging the strings
beside each other in the manner of an array, and then
gluing sheets of fabric to the cylindrical ends of the
pocketed springs, above and below, so as to form the unit.
In view of its relatively high cost, there is a desire to
reduce the quantity of adhesive used in the manufacture of
such units.
An alternative method of forming an array of pocketed
springs is described in our European Patent No. EP 19939473
in which springs are introduced between axially superposed
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sheets of material that are then joined at locations
between the springs.
The present invention is defined in the attached
independent claims, to which reference should now be made.
Further, preferred features may be found in the sub-claims
appended thereto.
According to one aspect of the present invention, there is
provided a resilient unit comprising a folded pad
containing rows of resilient elements in discrete pockets
formed between superposed sheets of material joined at
locations between adjacent resilient elements, wherein
between at least some adjacent resilient elements the
sheets form a gusset which acts as a hinge when the pad is
folded to form the resilient unit.
Preferably the pad comprises a plurality of gussets, each
between adjacent pairs of resilient elements in a
longitudinal direction of the pad.
Preferably successive gussets are located on alternate
sides of the folded pad.
Preferably at least some of the resilient elements have
axes that extend between gussets in the folded pad.
Preferably at least some of the resilient elements have
axes that are aligned in a substantially parallel fashion
in the folded pad.
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In a preferred arrangement, the sheets are joined at two or
more spaced locations between adjacent resilient elements
to form the gusset.
A single resilient element may be located between
successive gussets. Alternatively, or in addition, a
plurality of resilient elements may be located between
successive gussets in the pad.
The resilient elements may comprise springs. Preferably the
resilient elements comprise coil springs, which may be of
metal wire.
The springs may be substantially cylindrical in shape.
Preferably, the springs comprise plural coils and in at
least some springs the coil at one end, more preferably the
coils at each end, is of a reduced diameter. The springs
may be other than cylindrical, such as conical or barrel-
shaped for example. This is so that, when the pad is in the
folded configuration the free end or ends of the endmost
coils of adjacent springs do not interfere with or catch
upon one another.
For at least some of the springs the axial length of the
spring may exceed the maximum diameter of the spring.
Alternatively or in addition, for at least some of the
springs the axial length of the spring may be substantially
equal to, or may be less than, the maximum diameter of the
spring.
In the folded pad at least some adjacent resilient elements
may be attached together. The adjacent elements may be
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attached together along an axially extending surface, more
preferably a substantially cylindrical surface, of the
resilient elements in the folded pad. Adjacent elements may
be attached together for example by gluing or welding, such
as ultrasonic welding, of the sheet of material to itself.
Alternatively, or in addition, the folded pad may be held
in its folded configuration by a retention member, which
may comprise a frame or envelope. The retention member may
comprise a loop or band passing around the folded pad to
prevent it from unfolding.
Alternatively or in addition, the folded pad may be held in
its folded configuration by its attachment to a cover sheet
or sheets. The cover sheet or sheets may cover one or both
sides of the folded pad, and may be attached to the folded
pad by adhesive or more preferably by welding, preferably
to one or more positions which may comprise the gussets of
the pad.
Alternatively, or in addition, the folded pad may be
retained in a folded configuration by a case or bag. The
case or bag may include padding or cushioning material and
the folded pad inside the case may substantially comprise a
mattress.
In a preferred arrangement the folded unit comprises a fan-
folded, accordion-folded, concertina-folded or pleated pad.
The pad may be folded upon itself first one way and then
the other such that alternate gussets are located at first
one side then the other side of the folded unit.
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The sheets are preferably of a thermally weldable material,
such as spun-bonded polyester.
In the folded unit at least some rows of resilient elements
comprise a first plurality of springs and a second
plurality of springs superposed on, and/or axially
adjacent, the first plurality.
The first and second pluralities of springs may differ in
one or more characteristics including, but not limited to:
length, diameter, stiffness, shape, number of coils and
gauge of spring material.
The resilient unit may comprise plural rows of resilient
elements arranged in an array.
In the unfolded pad, adjacent rows of resilient elements
may be offset from one another. This is so that, when
folded, the springs are able to fit together more closely,
for example to nest, which helps to form a more stable pad.
The sheets of material on opposed sides of the unit may
differ from one another in respect of at least one
characteristic from a group including optical, thermal,
tactile, structural, chemical and physical.
The at least one characteristic may comprise the presence,
absence or degree of at least one property from a group
including, waterproof, probiotic, antibacterial,
antistatic, flavour, fragrance, flame-retardance,
elasticity, wear resistance and permeability.
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The first and second sheets of material may differ from one
another in thickness and/or weight.
In a preferred arrangement the first and second sheets may
differ from one another in one or more defined zones on one
or both layers, such that the layers may have substantially
identical characteristics in parts and may have different
characteristics in other parts.
The sheets are preferably joined around the periphery of
the unit.
According to a second aspect of the invention there is
provided a resilient pad for forming a resilient unit, the
pad comprising plural rows of resilient elements in
discrete pockets formed between superposed sheets of
material joined at locations between adjacent resilient
elements, wherein between at least some adjacent resilient
elements the sheets form a gusset which acts as a hinge
between resilient elements either side of the gusset when
the pad is folded to form a resilient unit.
The resilient pad may be in accordance with any statement
herein.
The invention also includes a method of making a resilient
unit, the method comprising forming a resilient pad by
encasing a plurality of resilient elements in discrete
pockets between superposed sheets of material joined at
locations between the resilient elements, forming between
at least some of the resilient elements a gusset, and fan-
folding the pad upon itself using the gussets as hinges,
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such that alternate gussets become located on opposed sides
of the folded unit and axes of at least some of the
resilient units become substantially parallel.
The invention also includes an article having at least one
resilient unit according to any statement herein.
The invention also includes a mattress comprising a
resilient unit according to any statement herein, or made
according to a method according to any statement herein.
In accordance with the invention there is provided a seat
comprising a resilient unit according to any statement
herein.
The seat may be a seat for use in relation to a vehicle,
such as a wheeled vehicle, an aircraft, spacecraft or a
ship or boat, or a saddle for an animal. The seat may
comprise a chair, stool, bench, sofa or settee.
In accordance with another aspect there is provided a table
comprising a resilient unit according to any statement
herein. The table may be an operating table or massage
table, for example.
In accordance with a further aspect of the present
invention there is provided an article of flooring
comprising a resilient unit according to any statement
herein. The article of flooring may comprise a carpet, or
carpet underlay, or a sport mat or exercise mat, or may be
a leisure or sports surface either for indoor use or for
outdoor use.
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In accordance with a still further aspect of the invention
there is provided a protective member, comprising a
resilient unit according to any statement herein. The
protective member may comprise an article of clothing or
headgear, or may be a protective shield to be worn on the
body of a user, or for attachment to an article.
According to a still further aspect of the invention there
is provided an article of packaging, comprising a resilient
unit according to any statement herein.
The invention may include any combination of the features
or limitations referred to herein, except such a
combination of features as are mutually exclusive, or
mutually inconsistent.
A preferred embodiment of the present invention will now be
described. By way of example only, with reference to the
accompanying diagrammatic drawings, in which:
Figure 1 is a side view of a first embodiment of resilient
unit at a first stage of manufacture;
Figure 2 is a side view of the unit of Figure 1 at a second
stage of manufacture,
Figure 3 is a side view of the unit at a third stage of
manufacture;
Figure 4 is a perspective view of the unit of Figure 3;
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Figure 5 is a side view of an alternative embodiment of
resilient unit at a second stage;
Figure 6 is a side view of the unit of Figure 5 at a third
stage of manufacture; and
Figure 7 shows a further alternative embodiment of
resilient unit in accordance with the present invention.
Resilient units for various uses, in accordance with
embodiments of the present invention, comprise pocketed
coil springs, which are sometimes referred to as encased
springs. The units typically comprise an array of metallic
coil springs individually encased in pockets formed by
bonding or otherwise joining together layers of material.
Turning to Figure 1, this shows, generally at 100, a pad
for making into a resilient panel, in accordance with an
embodiment of the present invention. The pad 110 is shown
in side view, and only a single set of pocketed springs can
be seen extending in a longitudinal direction indicated by
arrow X, which is also the direction in which the newly
formed pad is fed from the pocketing station (not shown).
In fact the pocketed springs are formed in an array, made
up of plural rows of springs side by side.
The pad comprises a number of springs 120 of coiled
metallic wire (shown in broken lines) encased in individual
pockets, one spring to a pocket in the example shown,
formed between superposed sheets 140 or layers of material
joined at positions P between the springs, preferably by
welding. The sheets 140 are joined at least at two spaced
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apart positions P between each pair of adjacent springs
120, so that a gusset 160, or pleat, is formed between each
pair of springs.
An example of an apparatus and a method for making the pad
shown in Figure 1 can be seen in our European Patent No. EP
1 993 947 Bl, the entire contents of which are incorporated
herein by reference.
Figure 2 shows a next step in the forming of the resilient
unit. The springs 120 have been turned within their
pockets, so that their axes A extend longitudinally,
between the weld points P. Turning the springs within their
pockets is achieved readily, particularly with tall
springs, as they have a tendency to turn in any case and
need only be urged to do so, for example by vibrating the
pad, or else by utilising a lip or ridge to catch an upper
leading edge of the spring, or a lower trailing edge,
thereby causing it to flip.
The pad is then folded, or pleated, in the manner of a fan,
concertina or accordion, so that alternate adjacent
pocketed springs are made to extend first one way, and then
the other way, to form a resilient unit 180. During
folding, the gussets act as hinges between rows of springs.
When the pad has been folded in this way the axes of
substantially all of the springs become aligned in a
direction that is generally transverse to the longitudinal
extent L of the unit 180.
Before folding, adhesive is applied at positions G on the
cylindrical surfaces of the pocketed springs. When the pad
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has been folded into the configuration depicted in Figure 3
the pocketed springs can be urged together, causing the
adhesive to join adjacent springs, thereby retaining the
pad in the folded configuration.
In one embodiment not shown, in the unfolded pad adjacent
rows of springs are offset from one another in a direction
across the pad, transverse to the axes of the springs, so
that when the pad is folded the springs nest, each between
two adjacent springs of a neighbouring row. This provides
for a more stable pad.
The resultant unit is as shown in Figure 4, which is a
perspective view in which the plural rows of springs can be
seen. The gussets 160 extend across the width of the unit,
alternately above and below adjacent springs.
The pad can initially be formed with other combinations of
springs, and an example of an alternative embodiment is
shown in Figures 5 and 6.
Figure 5 shows a pad in which two different types of spring
are encased in individual pockets. The diagram shows the
springs after they have been turned so that their axes
extend longitudinally, along the length of the pad, between
welding positions P. A set 120a of long springs is formed
with a second set 120b of shorter springs. The springs are
each located within their own pockets, created by joining
the sheets 140 together at positions P. Between adjacent
pairs of springs a gusset 160 is formed by spaced apart
welds at positions P, and successive pairs are oriented
alternately so that when the pad is folded in the manner of
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a fan, and glued, all of the shorter springs 120b are
located above the longer springs 120a in an integrated
stack.
The effect, in the finished unit 200, is of a layer of
short springs above a layer of long springs. Other
combinations of springs can be employed in the pad.
The springs can be chosen for their characteristics such as
stiffness and size and, as well as controlling the stacking
of different springs, the springs can be grouped into zones
along the extent of the unit, and combined in such a way as
to provide specifically desired
performance
characteristics. These characteristics can be determined by
the intended use of the resilient unit.
This versatility comes from the way in which the initial
pad is produced, in which the positions of the weld points
can be programmed using computer-controlled means to
produce whatever pattern is required.
Since the gusset 160 joins or connects pairs of adjacent
springs at one end, they need only be joined at a minimum
of one other place, which in the example (Figure 3) is the
adhesive point G on the cylindrical surface of the pocketed
spring. This leads to a significant saving, possibly up to
50%, on adhesive.
In an alternative embodiment, shown in Figure 7, the folded
pad may be held in its folded configuration by a retention
member in the form of a loop or band B passing around the
folded pad to prevent it from unfolding. The band B may be
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of the same material as the sheets 140, but does not have
to be. As an alternative (not shown) the retention member
may comprise a frame or envelope.
In another alternative embodiment (not shown), the folded
pad may be held in its folded configuration by its
attachment to a cover sheet or sheets. The cover sheet or
sheets may cover one or both sides of the folded pad, and
may be attached to the folded pad by adhesive or more
preferably by welding, preferably to one or more positions
which may comprise the gussets of the pad.
In a further alternative embodiment, the folded pad may be
retained in a folded configuration by a case or bag. The
case or bag may include padding or cushioning material and
the folded pad together with the case may substantially
comprise a mattress. The pad would be compressed axially
with respect to the springs and possibly also transversely
to this, between the edges, before being fed into the
padded case to form a complete mattress.
Reducing or even eliminating the glue usage has a
beneficial effect on the cost of production, and also makes
recycling more feasible. The glueless resilient mattress
can give up its steel springs easily and all of the pockets
remain joined together.
An additional substrate layer may be placed on top of the
pocketed springs, or below them, to improve comfort and/or
performance of the pad. The additional layer preferably
comprises natural materials such as hemp, cotton or wool,
to assist in the recyclability of the pad.
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At least some of the springs may have coils of different
diameters at opposed ends. Such springs have a number of
advantages over springs in which the coils at each end of
the spring are of substantially the same diameter. Firstly,
the springs can be compressed to a substantially flat
configuration, with the smaller diameter coils lying within
the larger diameter coils. If the springs can be compressed
entirely within themselves, such that no touching of
adjacent coils takes place, this also provides a much
quieter panel than is the case when the coils repeatedly
abut one another.
Furthermore, the stiffness of a wire spring can be
increased by reducing coil diameter, for a given gauge of
wire. Therefore a narrower gauge spring can be made which
uses less material to produce the same spring stiffness. A
spring consisting of coils which reduce in diameter has a
desirable characteristic, in that its stiffness increases
progressively as it is compressed.
In an embodiment not shown, coils at one, or more
preferably both, ends of the spring are of a reduced
diameter. This can help to avoid interference between
adjacent the free end coils of adjacent springs when the
pad is folded. The springs may be other than cylindrical,
and may be, for example, conical, or barrel-shaped.
Various types of material are used in the manufacture of
the above-described pocketed springs, and particularly
common is the use of non-woven, spun-bonded polyester, as
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this can readily be welded to itself using electrical
welding apparatus.
Many other combinations of springs and spring types may be
utilised in the resilient pad. These include, but are not
limited to: spring-within-spring arrangements, superposed
springs in stacks of two, three, four or more high, multi-
stage or multi-phase springs, such as hybrid springs of
different coil types, and springs of different heights
alternating along the top of the folded pad, in the manner
of castellations (sometimes referred to in the bed-making
industry as a "Hi-Lo" unit). All of these combinations can
also be combined with springs of different gauge, shape,
height and with different degrees of pre-tensioning within
the pockets.
The invention described above allows for an easy
incorporation of large numbers of springs in a resilient
unit. A higher spring count means that the desired
characteristics of the unit can be achieved using springs
of a lesser gauge and of a lesser diameter, which in turn
requires less filling material.
Whilst endeavouring in the foregoing specification to draw
attention to those features of the invention believed to be
of particular importance, it should be understood that the
applicant claims protection in respect of any patentable
feature or combination of features referred to herein,
and/or shown in the drawings, whether or not particular
emphasis has been placed thereon.
