Note: Descriptions are shown in the official language in which they were submitted.
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Systems and Methods for the Manufacture of Vertically
Oriented Fluted Multiwalls
Technical Field
The present invention pertains to means and method for manufacturing
multiwalls. More
particularly, the present invention pertains to systems and methods for
converting
transversely to vertically oriented cores of multiwalls.
Background
Multiwalls are commonly used in the construction of different types of plastic
furniture.
Their basic structure is sandwich having skin surfaces on top and bottom that
enclose a
core in the middle. The core is usually formed of transversely extending
flutes along the
length or width of the multiwall relative to the top and bottom skins. The
core provides
the mulitwall the strength to bear loads, particularly, when used in shelf
systems, closets,
.. cupboards and the like. To increase the strength of multiwalls the core is
oriented upright
relative to the skins. Several technologies have been developed for
manufacturing a core
that is 90 oriented relative to the top and bottom skins. These technologies
essentially
manufacture hollow vertical poles on the bottom surface then laminated from
top with the
upper surface, which evidently leads to complicated, time consuming and
expensive
process, resulting in a more expensive product.
There is, therefore, a need to provide cost-effective, relatively simple,
faster and cheaper
method for forming vertically oriented core of multiwalls and multiwall
comprising such
core.
Further, there is a need to provide relatively simple means for manufacturing
such
vertically oriented core of multiwalls and multiwall comprising such core.
The present invention responds to these objectives as detailed in the
following description
with exemplary reference to the accompanying drawings.
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Summary
in one aspect, the present invention provides a method of manufacturing
vertically
oriented core of multiwall and multiwall comprising such core. The manufacture
of
multiwalls with a core that contains vertical flutes is more complicated and
time
consuming than a core with a smaller number of transversely oriented flutes.
This is due
to the need to produce a larger number of shortened vertical flutes relative
to a smaller
number of transverse flutes to cover the same area. The method of the present
invention
essentially uses available materials, constructions and devices that make it
technologically simple and cost-effective relative to current technologies to
obtain the
same product.
Therefore, the method comprises a method for the manufacture of vertically
oriented
multiwall core, namely a core of a multiwall that comprises vertically
oriented flutes
relative to top and bottom skins that cover them. Such method comprises the
following:
(a) providing fluted multiwall or fluted core of multiwall that comprises at
least one array
of transversely oriented flutes;
(b) providing at least one cutting means configured for slicing the array of
transversely
oriented flutes of the fluted multiwall or fluted core of multiwall;
(c) placing the cutting means in contact at selected distance from first
longitudinal edge
of the fluted multiwall or fluted core of multiwall;
(d) cutting through a selected thickness of the fluted multiwall or fluted
core of multiwall
with the cutting means;
(e) generating a slice of the fluted multiwall or fluted core of multiwall;
(0 folding the slice relative the fluted multiwall or fluted core of multiwall
or a slice
previously cut off from said fluted multiwall or fluted core of multiwall;
(g) packing the folded slice with the previous folded slice;
(h) repeating steps (c)-(g) until reaching second longitudinal edge parallel
the first
longitudinal edge of the fluted multiwall or fluted core of multiwall.
Optionally, adjacent slices are heat-welded or heat-fused to each other after
folding.
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Optionally, adjacent slices are arranged in contact with each other by
pressing them
together, for example with a press applied on the two extreme slices of the
pack of slices
formed.
The folding of the slices after cutting may be done 90 clockwise relative to
the currently
forming vertically oriented multiwall, 90 counterclockwise relative to the
previously cut
slice or 1800 clockwise relative to the origin multiwall. In the last option
of folding, the
slices are packed one above the other in stack formation, where the last slice
cut is
positioned on top of the stack
To form the multiwall of the present invention, further step is required of
thermal
treatment for leveling the open bases of the shortened vertical flutes formed.
A further
step of laminating the top and bottom surfaces of the core completes the
process of
manufacturing the multiwall. Therefore, the method as detailed above further
comprises:
(i) stabilizing the upper and lower surfaces of the vertically oriented core
multiwall; and
(j) covering the upper and lower surfaces of the vertically oriented core
multiwall.
In one particular non-limiting embodiment, the slicing of the origin multiwall
with
transversely oriented flutes half- or part- thickness essentially creates
accordion
configuration of the slices that may be folded 900 relative each other
clockwise or
counterclockwise around the newly formed axis between them. To achieve that
the
slicing may be carried out with at least one knife that cuts through the
thickness of the
origin multiwall and along the longitudinal length perpendicular to the flutes
between the
first and second transverse edges of the origin multiwall. This slicing is
done at a selected
distance from the longitudinal edges of the multiwall or previous cuts. Thus
an array of
slices is obtained that may be folded one upon the other in an accordion
configuration.
The slicing may be done down to the bottom layer of the multiwall, leaving
only the
bottom layer that connects between adjacent slices and stretched when folding
them.
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In another particular embodiment, the slices are folded 1800 relative to the
origin
multiwall in stack formation, where they are packed one above the other, the
last slice
being on top. The multiwall is cut down to its bottom layer that connects
between
adjacent slices and stretched when folding them.
When the slicing is carried out in only one direction from one surface to the
opposite
surface, then the slices may be completely cut and separated from the origin
multiwall or
partly cut down to the bottom layer of the origin multiwall and folded 180 as
described
above. The slices may be folded by rotating them 900 clockwise one over the
other, then
welded to each other, for example by heat-welding or heat-fusion, or
mechanically
pressed together, thereby forming the core of vertically oriented shortened
flutes of the
multiwall of the present invention. Slicing in opposite directions from the
top and bottom
surfaces may be done for partial slicing down to the bottom layer of the
origin multiwall,
keeping the slices connected to each other. In the general case, a selected
horizontally
measured distance is set between the cutting means placed on each surface of
the origin
multiwall. One cutting means, for example a roller knife or a blade, cuts
through the
multiwall in opposite direction relative the other cutting means. This
opposite cutting is
required to enable the folding of adjacent slices over each other in 900
alternating
clockwise and counterclockwise directions, where the slices are still
connected to each
other in alternating upper and lower connecting lines.
The number of cutting means may be one or more. In one particular non-limiting
example, when the origin multiwall is mounted, for example, on conveyor belt,
then it is
transported relative to a cutting means placed in fixed position. The cutting
means is
moved down to cut a slice off of the multiwall, then moved up and the
multiwall
transported the distance selected for creating another slice. The slicing
repeats itself until
reaching the longitudinal edge of the multiwall.
In an alternative, cog-wheel with blades between neighbor teeth constantly
rolls over the
surface of the multiwall or core of multiwall, enabling the blades to cut
through its
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thickness and throughout the length. For example, top and bottom cog-wheels
with blades
between their teeth may be used to continuously cut slices off from a
multiwall or core of
multiwall traveling between them. The distance between the cog-wheels provides
sufficient space to allow a multiwall or core of multiwall to pass through
while being cut
part-, half- or full- way through their thickness.
In still another alternative, a plurality of cutting means may simultaneously
cut through
the thickness of the origin multiwall either completely or partially from the
two surfaces.
The folding step may be simultaneous with the cutting step, where every slice
formed is
folded over a previously cut slice and welded, fused or pressed to it, for
example by heat-
welding or heat-fusion or with use of a press, while a new slice is formed.
Thus a
continuous process for manufacturing vertically oriented multiwalls or cores
of
multiwalls is obtained.
Stabilizing with thermal treatment for leveling the top and bottom surfaces of
the core
and covering or lamination are done when completing the slicing and folding as
described above. In particular, the covering or lamination may be carried out
by heat-
welding, heat-fusion or gluing.
In one particular embodiment, the covering step is done with extruded sheets,
where each
sheet comprises at least two layers, where the layers are distinguished one
from the other
according to their MF1s (Melt Flow Index).
The covering with such sheets that form the covers comprises:
placing the covers on the upper and lower surfaces of the slices formed from
cutting the
transversely oriented flutes of the fluted multiwall or fluted core of
multiwall;
applying heating means over these covers; and
heating the covers.
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The heating is configured to turn at least part of the bottom layer of the
covers to
adhesive, where that adhesive bonds the laminates to the upper and lower
surfaces of the
slices. It should be noted that the MFI of the bottom layer is sufficient to
at least partly
melt and bond it to the slices.
In one particular embodiment, the upper and lower surfaces of the slices are
wavy,
indented and/or textured, where the adhesive formed from the bottom layer of
the cover
is configured to form mechanical and/or physical bond with the upper and lower
surfaces
of the slices. The top layer of the cover forms the skin of the multiwall and
is bonded to
the multiwall core upon melting the adhesive that is obtained from the bottom
layer of the
cover.
In one particular embodiment the bottom layer of the cover is foamed with
increased free
volume within to enable better spreading on and adhering to the top and bottom
surfaces
of the slices.
The method of manufacturing the multiwall with vertically oriented shortened
flutes is
not limited to a particular shape of flutes. Particular non-limiting examples
of cross
sections of the flutes in the origin multiwall may be selected from circular,
rectangular,
pentagonal, hexagonal, octagonal, parallelogram and diamond. The number of
layers of
flutes in the origin multiwall may also be more than one. Such example is
illustrated in
Figs. 10A-12C and 15 of the present application. Further, combinations of
flutes with
different cross-sections are also contemplated within the scope of the present
invention
(see Fig. 15).
The material from which the origin fluted multiwall or fluted core of
multiwall is made is
also not limited. In particular, the material may be selected from
polypropylene (PP),
polyethylene (PE), polyethylenterphthalate (PET), polystyrene (PS) and
polycarbonate
(PC).
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In another aspect, the present invention provides a machine configured for
manufacturing
vertically oriented multiwall core, where the system comprises:
conveyor belt configured for conveying fluted multiwall or fluted core of
multiwall that
comprises at least one array of transversely oriented flutes;
at least one cutting means configured for cutting through the fluted multiwall
or fluted
core of multiwall; and
positioning means configured for positioning the at least one cutting means in
contact
with upper and lower surfaces of the fluted multiwall or fluted core of
multiwall.
Further, the machine may comprise:
thermal treatment means configured for heat-welding or heat-fusing neighbor
slices cut
off from the origin multiwall to each other;
pressing means configured for pressing the slices to each other;
thermal treatment means configured for leveling the upper and lower surfaces
of the
newly formed core; and
laminating means configured for laminating these upper and lower surface.
In still another aspect, the present invention provides vertically oriented
multiwall
manufactured according to the method or with the machine as described above.
The following will describe particular and non-limiting examples of the
present invention
with exemplary reference to the drawings without departing from the scope and
spirit of
the present invention.
Brief Description of the Drawings
Figs. 1A-C schematically illustrate different perspectives of horizontally
fluted multiwall.
Figs. 2A-B schematically illustrate first step in a process manufacturing
fluted multiwall.
Figs. 3A-B schematically illustrate another first step a process of
manufacturing vertical
fluted multiwall.
Figs. 4A-B schematically illustrate second step in a process of manufacturing
vertical
fluted multiwall.
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Figs. 5A-B schematically illustrate third step in a process of manufacturing
vertical fluted
multiwall.
Figs. 6A-C schematically illustrate last step in a process of manufacturing
vertical fluted
multiwall and the multiwall manufactured.
Figs. 7A-C schematically illustrate different perspectives of hexagonal fluted
multiwall.
Figs. 8A-B schematically illustrate first step in a process of manufacturing
vertical
hexagonal fluted multiwall.
Figs. 9A-D schematically illustrate second to last steps in a process for
manufacturing
vertical hexagonal fluted multiwall.
Figs. 10A-C schematically illustrate different perspectives of double-layer
hexagonal
fluted multiwall.
Figs. 11A-C schematically illustrate the steps in a process for manufacturing
vertical
double-layer hexagonal fluted multiwall.
Figs. 12A-C schematically illustrate different perspectives of the vertical
double-layer
hexagonal fluted multiwall manufactured.
Figs. 13A-E schematically illustrate and summarize the steps of manufacturing
vertical
fluted multiwall.
Figs. 14 schematically illustrates a particular machine for manufacturing
vertical fluted
multiwall.
.. Fig. 15 illustrates triple layer core of transversely oriented multiwall
with combination of
cross-sections of its flutes.
Fig. 16 illustrates a particular procedure for covering the slices.
Detailed Description of the Drawings
.. The following describes different aspects of the method and machine of the
present
invention and in further detail and for demonstration purposes without
departing from the
scope and spirit of the present invention. It is understood that the
configuration(s) and
mode(s) of operation described herein do not limit the present invention to
the particulars
detailed below.
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Figs. 13A-E summarizes the process for manufacturing vertically oriented core
and
multiwall comprising it according to the present invention. A fluted core of a
multiwall is
first provided (Figs. 13A) with a transversely oriented array of flutes,
namely the flutes
that support the top and bottom skins of a multiwall stretch along its width.
The core of
the multiwall is vertically cut to selected depth through the thickness of the
multiwall
core and along its length with a plurality of cuts at selected distance from
each other. As
illustrated in Fig. 13B, a plurality of cutting means may simultaneously cut
through the
thickness of the core of a multiwall in parallel lines, where each two
adjacent cuts are
made from opposite sides to enable the folding step of the slices formed
fluent and
simultaneous with the cutting step. The third step in the process involves
heat treatment
of the top and bottom surfaces of the slices (Fig. 13C) to heat- or fuse- weld
the slices to
each other or press them together and form unified smooth surfaces for
laminating the top
and bottom skins as illustrated in Fig. 13D. The product of the process, which
is
vertically oriented core multiwall, is shown in Fig. 13E.
Figs. 1 through 5 illustrate the schematics of forming vertically oriented
core and
multiwall thereof in further detail. In Figs. 1A-C a transversely oriented
core of a
multiwall (1) is illustrated in different perspectives. The flutes (2) are
perpendicular to the
top and bottom skins (3a, 3b), adjacent each other, and extend along the width
of the
multiwall.
The first step of converting transversely to vertically oriented core of
multiwall can be
carried out in two exemplary methods as illustrated in Figs. 2A-2B and 3A-3B.
Knives or
blades (4a, 4b) are simultaneously placed in contact with the top and bottom
surfaces of
the core or skins (3a, 3b) for that matter and at selected distance between
their points of
contact. The knives/blades (4a, 4b) cut through the depth of the
core/multiwall a selected
depth (5a), for example, down to a bottom layer of the origin multiwall, that
enables
folding the slices (5) formed in the next step (shown in Fig. 2B). In one
option, after
reaching the desired depth, the knives/blades (4a, 4b) extend the cut formed
at the point
of entry along the length of the core or multiwall. In another option, the
blade is at least
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the width of the width of the origin multiwall, so the slice is formed with
one cut. As a
result, a slice is cut off from the entire row of flutes (2). The
knives/blades (4a, 4b) then
define another distance between them that is adjacent the former distance, and
repeat the
cutting process forming another slice (5). Each slice (5) is folded 90 around
the newly
.. formed axis represented by (5a) relative to the original axis of rotation
of the flutes,
where each two adjacent slices are folded one in clockwise direction, the
other in
counterclockwise direction in accordion fashion. Alternatively, the slices are
folded 180
towards the origin mulitwall in stack formation as described above. As shown
in Fig. 2B
the steps of slicing and folding can be carried out continuously with each
other. Namely,
the slices formed are folded 90 or 180 while knives/blades (4a, 4b) continue
to cut new
slices. The particular example in Fig. 2B shows that the core/multiwall
advances a
selected distance towards the folding area while the knives/blades (4a, 4b)
stay in fixed
position relative to it. Alternatively, the core/multiwall may be fixed in
place, while the
knives/blades (4a, 4b) move along its width a selected distance each time. In
a third
option, both the knives and multiwall or core of multiwall move one relative
to the other
in opposite directions.
Figs. 3A-B exemplify variation of the method of forming a vertically oriented
core of
multiwall. In this method the slices (5) are entirely cut off and separated
from the
core/multiwall (1). Accordingly, only one knife or blade (4a) is required. The
slices (5)
are collected and packed in vertical position relative to their axis of
rotation and top and
bottom surfaces of the skins that will cover them. Thermal treatment and
lamination
follow the cutting and folding steps.
Figs. 4A-B illustrate the following step of stabilizing the core of arrays of
vertical
shortened flutes adjacent each other. Presses (6a, 6b) apply isostatic
pressure on the open
ends of the slices of flutes (5) from parallel opposite sides, thereby
leveling and
smoothing the surfaces for the following step of covering or lamination and
heat- or fuse-
welding adjacent slices to each other or the slices are mechanically pressed
to each other.
Figs. 5A-B show the final step of laminating the slices (5) according to each
of the
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cutting versions presented in the previous Figs. For each, the lamination or
covering is
essentially the same, closing the open ends of the slices (5) with laminates
(7a, 7b)
attached to them with heat-welding, heat-fusion or gluing. The core obtained
may then be
used for different purposes and uses by overlaying different covers on it.
Fig. 16 schematically illustrates a particular procedure for covering the
slices (5) with
covers (7a, 7b). Particularly, covers (7a, 7b) are composed of two layers (a,
b) that form
an extruded sheet, where each layer has a different MFI (Melt Flow Index)
relative to the
other layer. Using extrusion to form the covers (7a, 7b) enables the adhesion
of the two
layers (a, b) to each other. When contacting the covers (7a, 7b) to the outer
surfaces of
the slices (5) core and applying heat, layer (a), which is in direct contact
with the slices
(5) melts over their top ends and functions as adhesive to bond the covers
(7a, 7b) to the
slices (5). Now, due to the difference in MFIs of the two layers (a) and (b),
layer (a)
absorbs the heat and melts, where layer (b) remains intact and forms the outer
surface of
the vertical multiwall. The melted layer (a) may bond to the outer surfaces of
the slices
(5) in any way known for adhesives, for example mechanical by infiltrating
into crevices
and holes in the surface of the slices (5) and/or increasing friction between
the cover and
surface of the slices and/or physical by generating physical bonds between the
adhesive
molecules and the molecules of the material of the slices (5) at their
surface.
The (b/c) indication in Fig. 16 signifies the eventual result, where layer (a)
no longer
exists in the form of a continuous layer with defined dimensions but rather as
adhesive
layer that connects between layer (b) that forms the skin of the multiwall
structure, and
the surface of the slices (5). The structure of the multiwall, thus, is now
defined by the
slices (5) core and the outer layer (b) of the extruded sheets, i.e., covers
(7a, 7b).
In a particular embodiment, the bottom surface of the extruded sheet, that is
the bottom
surface of layer (a) that comes in contact with the surfaces of the slices
(5), is not smooth.
For example, such surface may be wavy, indented and/or textured to match
waviness,
indentation and/or texture of the surfaces of the slices (5) that result in
the process of
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cutting the transverse flutes to form perpendicular flute core. In such case,
layer (a) may
better function as adhesive upon melting and optionally slightly pressing, due
to the
plurality of crevices and holes at the slices surfaces into which the adhesive
can infiltrate
and form a stronger bond, mechanical and/or physical.
.. The vertically oriented multiwall core (1') is shown in different
perspectives in Figs. 6A-
C. The slices or arrays (5) of now vertically oriented shortened flutes are
packed one next
to the other, welded or fused together ordered in place after removing
mechanical
pressure applied on the slices, and covered with top and bottom covers (7a,
7b). The
multiwall core (1') formed is, therefore, obtained in a relatively simple and
cost-effective
process without complex technologies or machinery.
Heat may be applied also to relieve tension built in the core as in the
cutting and folding
process.
Vertically oriented core multiwall can be essentially done with any shape of
flutes and/or
any form of packing. Figs 7A-9D demonstrate the same process described above
for
flutes with hexagonal cross section (8a). Here also the array of flutes is
sliced to multiple
slices. The gap between adjacent flutes (8a) contains a horizontal film (8b)
connecting
between them, which is cut and separated from the array (8) in the slicing
step. The slices
(8c) formed may remain connected to each other in an axis of rotation (8d) and
rotated
900 clockwise or counterclockwise to form adjacent arrays of shortened
vertically
oriented hexagons (8c) packed together to form the core of the multiwall (see
Fig. 9D).
Alternatively, the slices are folded 180 relative to the origin multiwall and
packed in
stack formation as explained above. Otherwise, they may be completely cut off
from each
.. other and then packed in vertical position relative to their axis of
rotation. Thermal
treatment and lamination with covers (7a, 7b) are then carried out on the top
and bottom
surfaces.
Double layer core of hexagonal flutes (9) is demonstrated in Figs. 10A-C in
which the
gap in the lower array of hexagonal flutes (9a) is now occupied with a second
layer of
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hexagonal flutes (9b). The process of manufacturing a vertically oriented core
of
multiwall (1') is illustrated in Figs. HA-C and essentially the same as the
process shown
in Figs. 2A-5B. This time, however, two layers of hexagonal flutes (9a, 9b)
are sliced in
each cut, folded 900 (clockwise or counterclockwise) around the axis (9e)
formed
.. between adjacent slices to form vertically oriented arrays of shortened
hexagonal flutes
(9c) or 1800 towards the origin multiwall in stack packing formation. The two
layers now
result in fully packed core without gaps between the shortened hexagonal
vertical flutes
(see Figs. 12A-C). The top and bottom surfaces of the double-layer hexagonal
flutes core
are stabilized and laminated to form the double-layer hexagonal vertical
multiwall core
(see Figs. 11B-C).
Fig. 15 shows a triple layer core of multiwall with alternating layers of
pentagonal and
hexagonal flutes. Essentially, the arrangement or layer number of flutes in
the core does
not affect the method of the present invention for manufacturing multiwalls
with
vertically oriented core. Therefore, any number of layers of flutes with
varying cross
sections is well within the scope of the present invention.
Fig. 14 schematically illustrates front view of particular machine for
manufacturing
vertically oriented core multiwalls. Two cog-wheels (10a, 10b) are placed
beside each
other, with. their axes or rotation parallel one to the other. Blades (11) are
inserted
between adjacent teeth of each cog-wheel to cut slices from multiwalls (1)
with
transversely oriented core that pass between the wheels (10a, 10b). The slices
leaving the
space between the two wheels (10a, 10b) are then folded 90 or 180 back on
the origin
multiwall, and processed further with thermal treatment and lamination (12).
It should be noted, that the cross sectional shapes of the flutes described
above and
illustrated in the accompanying drawings are only examples of the possible
shapes of
flutes that may be used to form vertically oriented flute core. Therefore,
rectangular,
circular, parallelogram, octagonal and diamond shapes are other examples that
may be
used to manufacture vertically oriented cores of multiwalls. Further,
transversely oriented
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cores with more than one layer may be used to manufacture the vertically
oriented core of
multiwall.
Those skilled in the art to which this invention pertains will readily
appreciate that
numerous changes, variations and modifications can be made without departing
from the
scope of the invention mutatis mutandis.
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