Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND APPARATUS FOR FABRICATING STRETCH FILM ROLLS
Field of the Invention
[0001] The present invention relates generally to stretch film and in
particular,
to a method and apparatus for fabricating stretch film rolls.
Background of the Invention
[0002] Stretch film is widely used for wrapping and securing
palletized loads
for shipping. This is partly due to the fact that stretch film exhibits a
"memory", or a
tendency to shrink, upon stretching. For example, stretch film that is
stretched by an
amount of 10% will shrink nearly 10% of its stretched length. This "memory"
assists
in securing wrapped palletized articles together under compression.
[0003] Stretch film is fabricated in the form of stretch film rolls.
Each stretch
film roll may be used to manually wrap a palletized load, or may be loaded
into an
automated wrapping machine.
[0004] In some situations, the tensile strength of conventional
stretch film
may be insufficient to withstand tensile forces applied during wrapping, which
can
cause the stretch film to tear during wrapping.
[0005] Improvements are generally desired. It is therefore an object
at least to
provide a novel method and apparatus for fabricating stretch film rolls.
Summary of the Invention
[0006] In one aspect, there is provided apparatus for fabricating a
stretch film
roll, comprising: a device configured to fold a stretch film web to yield a
folded
stretch film web comprising at least one longitudinal band of increased
thickness,
each band of increased thickness being spaced from the longitudinal edges of
the
folded stretch film web; at least one component configured to be oscillated
for
oscillating the folded stretch film web; and a driven winding shaft for
winding the
folded stretch film web into a roll, wherein the at least one component
configured to
be oscillated is one or more of: at least one roller, at least one additional
guide, the
device, and the winding shaft.
CA 2856999 2018-03-02
- 2 -
[0007] Each band of increased thickness may comprise a plurality of
longitudinal folds. The at least one band of increased thickness may comprise
a
longitudinal band of wrinkled or bunched stretch film web. The at least one
band of
increased thickness may comprise a longitudinal pleat. The pleat may comprise
at
least two longitudinal folds.
[0008] The device may comprise: a member having at least one folding
edge,
and at least one guide, each guide configured to cooperate with a respective
folding
edge to form a respective longitudinal band of increased thickness. Each guide
may
be a generally conically-shaped tip. Each guide may be generally disc-shaped.
Each
generally disc-shaped guide may be configured to be rotatable. The member may
be:
a form defining at least one longitudinal channel, or at least one guide
member. Each
guide member may comprise a generally disc-shaped guide. Each generally disc-
shaped guide may be configured to be rotatable.
[0009] The at least one component may be configured to be oscillated
along
an axis that is generally orthogonal to a direction of travel of the folded
stretch film
web. The at least one component may be configured to be oscillated over either
a
fixed distance or a variable distance. The at least one component may be
configured
to be oscillated at either a fixed frequency or a variable frequency.
[00010] The winding shaft may support a core onto which the folded
stretch
film is wound. The winding shaft may be a coreless winding shaft onto which
the
folded stretch film is wound.
[00011] The stretch film web may be fabricated by the apparatus. The
stretch
film web may be provided to the apparatus as a rolled supply of previously-
fabricated
stretch film web.
[00012] In another aspect, there is provided a method for fabricating
a stretch
film roll, comprising: providing a stretch film web; folding the stretch film
web using
a device to yield a folded stretch film web comprising at least one
longitudinal band
of increased thickness, each band of increased thickness being spaced from the
longitudinal edges of the folded stretch film web; oscillating the folded
stretch film
web using at least one component configured to be oscillated; and winding the
folded
stretch film web, wherein the at least one component configured to be
oscillated is
one or more of: at least one roller, at least one guide, the device, and a
winding shaft.
CA 2856999 2018-03-02
-3 -
[00013] The folding may comprise applying the stretch film web against
at
least one folding edge to fon-n said at least one longitudinal band of
increased
thickness. The at least one longitudinal band of increased thickness may
comprise a
band of wrinkled or bunched stretch film web. The at least one longitudinal
band of
increased thickness may comprise a longitudinal pleat. Each pleat may comprise
at
least two longitudinal folds.
[00014] The oscillating may comprise oscillating one or more of the
following
along an axis that is generally orthogonal to a direction of travel of the
folded stretch
film web: at least one roller, at least one additional guide, the device, and
the winding
shaft.
[00015] The providing may comprise fabricating the stretch film web.
The
providing may comprise providing a rolled supply of previously-fabricated
stretch
film web.
[00016] In another aspect, there is provided a method, comprising:
providing a
stretch film web; passing the stretch film web between a member and at least
one
guide, the member comprising at least one channel, the at least one guide
cooperating
with the at least one channel to yield a folded stretch film web comprising at
least one
longitudinal band of increased thickness; and oscillating the folded stretch
film web
using at least one component configured to be oscillated, wherein the at least
one
component configured to be oscillated is one or more of: at least one roller,
the
member, the at least one guide, at least one additional guide, and a winding
shaft.
[00017] The at least one guide may cooperate with the at least one
channel to
wrinkle or bunch the stretch film web. The at least one guide may cooperate
with the
at least one channel to form a pleat.
[00018] The providing may comprise fabricating the stretch film web.
The
providing may comprise providing a rolled supply of previously-fabricated
stretch
film web.
CA 2856999 2018-03-02
CA 02856999 2014-07-16
- 4 -
Brief Description of the Drawings
[00019] Embodiments will now be described more fully with reference to the
accompanying drawings in which:
[00020] Figure 1 is a side view of a portion of an apparatus for
fabricating
stretch film rolls, during use;
[00021] Figure 2 is a perspective view of a folding device forming part of
the
apparatus of Figure 1;
[00022] Figure 3 is a sectional front view of the folding device of Figure
2;
[00023] Figure 4 is a sectional perspective view of the folding device of
Figure
2, during use;
[00024] Figure 5 is a sectional view of a portion of a folded stretch film
web
formed using the apparatus of Figure 1;
[00025] Figure 6 is a sectional front view of another embodiment of a
folding
device forming part of the apparatus of Figure 1;
[00026] Figure 7 is a sectional perspective view of the folding device of
Figure
6, during use;
[00027] Figure 8 is a sectional view of a portion of a folded stretch film
web
formed using the apparatus of Figure 6;
1000281 Figure 9 is a perspective view of another embodiment of a folding
device forming part of the apparatus of Figure 1;
[00029] Figure 10 is a sectional perspective view of the folding device of
Figure 9, during use;
[00030] Figure 11 is a sectional front view of the folding device of Figure
9,
during use;
[00031] Figure 12 is a perspective view of another embodiment of a folding
device forming part of the apparatus of Figure 1;
[00032] Figure 13 is a perspective view of the folding device of Figure 12,
during use;
[00033] Figure 14 is a sectional front view of the folding device of Figure
12,
during use;
[00034] Figure 15 is a sectional view of a portion of another embodiment of
a
folded stretch film web formed using the apparatus of Figure 6; and
CA 02856999 2014-07-1.6
-5-
1000351 Figure 16 is a sectional view of a portion of still another
embodiment
of a folded stretch film web.
Detailed Description of the Embodiments
[00036] Turning now to Figure 1, a portion of an apparatus for fabricating
stretch film rolls is shown, and is generally indicated by reference numeral
20.
Apparatus 20 comprises an extruder (not shown) that is configured to dispense
a
continuous sheet of plastic film onto a surface of a rotating cast roller (not
shown) so
as to form a stretch film web 22. Apparatus 20 also comprises a set of
preliminary
rollers (not shown) configured to receive the stretch film web 22 from the
cast roller.
1000371 Apparatus 20 further comprises a folding device 30 that is
positioned
downstream from the set of preliminary rollers, and that is configured to
receive the
stretch film web 22 from the set of preliminary rollers. The folding device 30
may be
better seen in Figures 2 to 4. Folding device 30 comprises a form 32, which
has a
web-facing surface 34 over which the moving stretch film web 22 travels. In
this
embodiment, the form 32 also has two (2) channels 36, each of which extends
along a
longitudinal side of the form 32 in the direction of travel of the stretch
film web 22.
Each channel 36 is shaped so as to define a longitudinal folding edge 38
extending
along a longitudinal edge of the planar surface 34.
1000381 The folding device 30 also comprises two (2) guides 46 positioned
at
the sides of the form 32. Each guide 46 is terminated by a rounded, generally
conical
tip that is sized to engage a respective channel 36, and each guide 46 is
coupled to an
adjustable positioning apparatus (not shown) for enabling the position of the
guide 46
relative to the channel 36 to be adjusted as necessary. Each guide 46 is
configured to
cooperate with its respective folding edge 38 to form a pleat within the
stretch film
web. Specifically, each guide 46 is configured to direct a portion of the
moving
stretch film web 22 into the channel 36 and against the folding edge 38, which
in turn
causes a portion of the moving stretch film web 22 to fold onto itself
downstream
from the guide 46 and thrm a pleat. In this embodiment, the folding device 30
is
configured to form a folded stretch film web 50 comprising two (2) pleats 52,
with
each pleat 52 comprising two (2) folds separated by a width of about 0.3
inches, as
may be seen in Figure 5. The folding device 30 is also configured such that
each pleat
CA 02856999 2014-07-16
-6-
52 is spaced from the nearest longitudinal edge of the folded stretch film web
50 by at
least a distance corresponding to the width of the pleat.
[00039] The apparatus 20 further comprises a first intermediate roller 62
that is
configured to receive the folded stretch film web 50 from the folding device
30, and a
second intermediate roller 64 that is configured to receive the folded stretch
film web
50 from the first intermediate roller 62. In this embodiment, the first
intermediate
roller 62 and the second intermediate roller 64 are configured as idler
rollers.
[00040] Additionally, in this embodiment, the second intermediate roller 64
is
configured to be oscillated along an oscillation axis that is generally
orthogonal to the
direction of travel of the folded stretch film web 50, so as to cause the
moving folded
stretch film web 50 to also be oscillated. At least one assembly (not shown)
is
provided for oscillating the second intermediate roller 64 along the
oscillation axis.
The second intermediate roller 64 is oscillated at a fixed frequency and over
a fixed
distance along the oscillation axis. In this embodiment, the fixed frequency
is a
frequency in the range from about 0.1 cycles per minute to about 200 cycles
per
minute, and the fixed distance, and namely the distance travelled during one
cycle, is
a distance in the range from about 0.1 inches to about 4 inches.
[00041] Apparatus 20 further comprises a roller 66 that is configured to
receive
the oscillated, folded stretch film web 50 from the second intermediate roller
64.
Apparatus 20 further comprises a winding shaft 68 positioned adjacent the
roller 66
and supporting a core 72. The winding shaft 68, with the core 72 supported
thereon,
is configured to receive the oscillated folded stretch film web 50 from the
roller 66 for
winding the oscillated folded stretch film web 50 onto the core 72, so as to
form a
stretch film roll, and namely a roll of folded stretch film. An assembly (not
shown) is
provided for rotatably driving the winding shaft 68. The surface of the folded
stretch
film wound onto the core 72 is generally in contact with the surface of the
roller 66,
so as to prevent air entrapment between layers of the folded stretch film
during
winding. In this embodiment, the roller 66 is configured as an idler roller.
[00042] In use, the extruder dispenses a continuous sheet of plastic film
onto
the surface of the rotating cast roller to form the stretch film web 22, which
is then
received by the set of preliminary rollers. From the set of preliminary
rollers, the
stretch film web 22 travels downstream and is received by the folding device
30. As
CA 02856999 2014-07-16
= =
- 7 -
the stretch film web 22 travels through the folding device 30, it passes over
the planar
surface 34 of the form 32 and is directed into the channels 36 by the guides
38, so as
to yield a folded stretch film web 50 comprising pleats 52.
[00043] Downstream from the folding device 30, the folded
stretch film web 50
is received by the first intermediate roller 62, and in turn by the second
intermediate
roller 64. The second intermediate roller 64 is oscillated along the
oscillation axis,
which in turn causes the folded stretch film web 50 to be oscillated. From the
second
intermediate roller 64, the oscillated, folded stretch film web 50 is received
by the
roller 66, and in turn by the winding shaft 68 supporting the core 72, at
which the
oscillated, folded stretch film web 50 is wound onto the core 72 so as to form
the roll
of folded stretch film.
[00044] As will be appreciated, each pleat effectively triples
the thickness of
the stretch film, and thereby provides a band of reinforcement extending the
length of
the folded stretch film. As a result, the pleats advantageously increase the
tensile
strength of the folded stretch film and render the folded stretch film less
prone to
tearing during use, such as for example during wrapping of palletized loads
for
shipping, as compared to conventional stretch film.
[00045] Additionally, and as will be appreciated, the spacing of
each pleat from
the longitudinal edge of the folded stretch film advantageously allows the
reinforcement provided by the pleats to be distributed across a greater
portion of the
width of the film.
[00046] Further, and as will appreciated, oscillation of the
folded stretch film
web prevents direct overlap of the pleats during winding, and thereby allows
the
shape of the roll of folded stretch film to be controlled. As will be
understood, as a
result of the oscillation, the roll of folded stretch film has a generally
smooth contour,
and without large bulges that would otherwise form due to direct overlap of
the pleats
in absence of oscillation. Additionally, prevention of direct overlap of the
pleats
during winding advantageously reduces or eliminates additional tension within
the
film caused by overlapping pleats, which would otherwise cause problems during
unwinding of the film.
[00047] Other configurations of the folding device are possible.
For example,
Figures 6 and 7 show another embodiment of a folding device, which is
generally
CA 02856999 2014-07-16
- 8 -
indicated by reference numeral 130. Folding device 130 is generally similar to
folding device 30 described above and with reference to Figures 2 to 4, and
comprises
a form 132. The form 132 has a plurality of web-facing surfaces 134 over which
the
moving stretch film web 22 travels. In this embodiment, the form 132 also has
four
(4) channels, namely two (2) outer channels 136 and two (2) inner channels
142.
Each outer channel 136 extends along a longitudinal side of the form 132 in
the
direction of travel of the stretch film web 22. Each outer channel 136 is
shaped so as
to define a longitudinal folding edge 138 extending along the longitudinal
edge of a
planar surface 134. Each inner channel 142 extends intermediate the
longitudinal
sides of the form 132 and in the direction of travel of the stretch film web
22. Each
inner channel 142 is shaped so as to define a longitudinal folding edge 144
extending
along a longitudinal edge of a planar surface 134.
[00048] The folding device 30 also comprises four (4) guides, namely two
(2)
outer guides 146 positioned at the sides of the form 132 and two (2) inner
guides 148
positioned intermediate the sides of the form 132. Each guide 146 and 148 is
terminated by a rounded, generally conical tip that is sized to engage a
respective
channel, and is coupled to an adjustable positioning apparatus (not shown) for
enabling the position of the guide relative to the channel to be adjusted as
necessary.
Each outer guide 146 is configured to cooperate with its respective folding
edge 138
to form a pleat within the stretch film web. Specifically, each outer guide
146 is
configured to direct a portion of the moving stretch film web 22 into the
outer channel
136 and against the folding edge 138, which in turn causes a portion of the
moving
stretch film wcb 22 to fold onto itself downstream from the guide 146 and form
a
pleat. Similarly, each inner guide 148 is configured to cooperate with a
respective
folding cdgc 144 to form a pleat within the stretch film web. Specifically,
each inner
guide 148 is configured to direct a portion of the moving stretch film web 22
into the
inner channel 142 and against the folding edge 144, so as to cause a portion
of the
moving stretch film web 22 to fold onto itself downstream from the guide 148
and
form a pleat. In this embodiment, the folding device 130 is configured to fonn
a
folded stretch film web 150 comprising four (4) pleats 52, with each pleat 52
comprising two (2) folds separated by a width of about 0.3 inches, as may be
seen in
Figure 8. The folding device 130 is also configured such that each pleat 52 is
spaced
CA 02856999 2014-07-16
- 9 -
from the nearest longitudinal edge of the folded stretch film web 150 by at
least a
distance corresponding to the width of the pleat.
[00049] Figures 9 to 11 show another embodiment of a folding device, which
is
generally indicated by reference numeral 230. Folding device 230 is generally
similar
to folding device 30 described above and with reference to Figures 2 to 4, and
comprises a form 232 that has a web-facing surface 234 over which the moving
stretch film web 22 travels. In this embodiment, the form 232 also has two
inclined,
longitudinal side surfaces 236 extending the length of the form 232 in the
direction of
travel of the stretch film web 22. Each longitudinal side surface 236 defines
a
longitudinal folding edge 238 extending along the longitudinal edge of the
planar
surface 234.
[00050] The folding device 230 also comprises two (2) guide members 262,
with each guide member 262 positioned adjacent a longitudinal side surface 236
of
the form 232. Each guide member 262 comprises a generally disc-shaped guide
266
mounted to an axle 268, and is coupled to an adjustable positioning apparatus
(not
shown) for enabling the position of the guide 266 relative to the form 232 to
be
adjusted as necessary. In this embodiment, each guide member 262 is configured
to
rotate freely about its axle 268, such that each guide 266 is rotatable.
[00051] Each guide 266 is configured to cooperate with its respective
folding
edge 238 to form a pleat within the stretch film web 22. Specifically, each
guide 266
is configured to direct a portion of the moving stretch film web 22 toward the
longitudinal side surface 236 and against the folding edge 238, so as to cause
a
portion of the moving stretch film web 22 to fold onto itself downstream from
the
guide 266 and form a pleat. In this embodiment, the folding device 230 is
configured
to form the folded stretch film web 50 comprising two (2) pleats 52, with each
pleat
52 comprising two (2) folds separated by a width of about 0.3 inches, as
described
above and with reference to Figure 5. The folding device 230 is also
configured such
that each pleat 52 is spaced from the nearest longitudinal edge of the folded
stretch
film web 50 by at least a distance corresponding to the width of the pleat.
[00052] In other embodiments, one or more of the guide members may
alternatively be fixed, and not be configured to rotate freely. In one such
embodiment, the guide(s) of the fixed guide member(s) may alternatively have a
CA 02856999 2014-07-16
- 10 -
shape other than generally disc-shaped. For example, in one such embodiment,
the
guide(s) of the fixed guide member(s) may alternatively be shaped as half-
disc(s). It
will be understood by those of skill in the art that other guide shapes may
alternatively
be used.
[00053] Figures 12 to 14 show another embodiment of a folding device, which
is generally indicated by reference numeral 330. Folding device 330 comprises
a
plurality of guide members arranged in a spaced relationship. Specifically,
the
folding device 330 comprises a pair of first guide members 362 and a pair of
second
guide members 364. Each first guide member 362 comprises a generally disc-
shaped
guide 366 mounted to an axle 368. Each second guide member 364 is similar to
the
first guide member 362, and comprises a generally disc-shaped guide 376
mounted to
an axle 378. Each first guide member 362 is coupled to an adjustable
positioning
apparatus (not shown) for enabling the position of the guide 366 relative to
the guide
376 of the second guide member 364 to be adjusted as necessary. In this
embodiment, each guide member 362 and 364 is configured to rotate freely about
its
axle 368 and 378, respectively, such that each guide 366 and 376 is rotatable.
[00054] Each first guide member 362 is configured to cooperate with a
respective second guide member 364 to form a pleat within the stretch film web
22.
Specifically, each guide 366 is configured to direct a portion of the moving
stretch
film web 22 against a folding edge defined by the proximal edge 382 of each
guide
376, so as to cause a portion of the moving stretch film web 22 to fold onto
itself
downstream of the guides 366 and 376 (not shown) and form a pleat. In this
embodiment, the folding device 330 is configured to fouli the folded stretch
film web
50 comprising two (2) pleats 52, with each pleat 52 comprising two (2) folds
separated by a width of about 0.3 inches, as described above and with
reference to
Figure 5. The tblding device 230 is also configured such that each pleat 52 is
spaced
from the nearest longitudinal edge of the folded stretch film web 50 by at
least a
distance corresponding to the width of the pleat.
100055J In other embodiments, one or more of the first guide members and
the
second guide members may alternatively be fixed, and not be configured to
rotate
freely. In such embodiments, the guide(s) of the fixed guide member(s) may
alternatively have a shape other than generally disc-shaped. For example, in
one such
CA 02856999 2014-07-16
- 11 -
embodiment, the guide(s) of the fixed guide member(s) may alternatively be
shaped
as half-disc(s). It will be understood by those of skill in the art that other
guide shapes
may alternatively be used.
[000561 Although in the embodiments described above, the folding device is
configured to form a folded stretch film web comprising either two (2) or four
(4)
pleats, in other embodiments, the folding device may alternatively be
configured to
form a folded stretch film web comprising a different number of pleats, such
as one
(1) pleat, three (3) pleats, or more than four (4) pleats. It will be
understood that in
such alternative embodiments, the folding device would be suitably configured
and
have a suitable number of guide(s) to form the corresponding number of
pleat(s).
[000571 Although in the embodiments described above, each pleat comprises
two (2) folds separated by a width of about 0.3 inches, in other embodiments,
one or
more pleats may alternatively comprise two (2) folds separated by a width in
the
range from about 0.0625 inches to about 4 inches. Still greater widths may be
used.
[00058] Although in embodiments described above, each pleat is spaced from
the nearest longitudinal edge of the folded stretch film web by at least a
distance
corresponding to the width of the pleat, in other embodiments, each pleat may
alternatively be spaced from the nearest longitudinal edge of the folded
stretch film
web by a distance of about 0.0625 inches or more.
[00059] The folding devices of the embodiments described above may
alternatively bc used to yield stretch film rolls comprising one or more
longitudinal
bands of wrinkled or bunched film. For example, during use of the folding
device
130 described above and with reference to Figures 6 and 7, different operating
conditions may result in the foi-mation of one or more bands of wrinkled or
bunched
film instead of pleats.
[000601 For example, in one embodiment, under different operating
conditions,
each inner guide 148 of the folding device 130 may be configured to direct a
portion
of the moving stretch film web 22 into the inner channel 142, so as to cause a
portion
of the moving stretch film web 22 to wrinkle or bunch downstream from the
guide
148 to form a longitudinal band of wrinkled or bunched stretch film web. In
this
embodiment, the folding device 130 is configured to form a folded stretch film
web
450 comprising two (2) pleats 52, with each pleat 52 comprising two (2) folds
CA 02856999 2014-07-16
- 12 -
separated by a width of about 0.3 inches, and two (2) longitudinal bands 454
of
wrinkled or bunched stretch film web, as may be seen in Figure 15. Each
longitudinal
band 454 comprises a wrinkled or bunched portion of stretch film web that has
increased thickness and that comprises a plurality of longitudinal folds. Each
longitudinal band 454 is spaced from the nearest longitudinal edge of the
folded
stretch film web 450 by at least a distance corresponding to the width of the
longitudinal band. In this embodiment, each longitudinal band 454 has a width
of
about 0.3 inches.
[00061] The folded stretch film web 450 then travels through the apparatus
20
downstream from the folding device 130, in generally the same manner as
described
above for folded stretch film web 50. For example, the second intermediate
roller 64,
which is configured to be oscillated along the oscillation axis that is
generally
orthogonal to the direction of travel of the folded stretch film web 450,
causes the
moving folded stretch film web 450 to also be oscillated. Also, the winding
shaft 68,
with the core 72 supported thereon, is configured to receive the oscillated
folded
stretch film web 450 from the roller 66 for winding the oscillated folded
stretch film
web 450 onto the core 72, so as to form a stretch film roll, and namely a roll
of folded
stretch film.
[00062] As will be appreciated, each longitudinal band of wrinkled or
bunched
stretch film increases the thickness of the stretch film, and thereby provides
a band of
reinforcement extending the length of the folded stretch film. As a result,
the
longitudinal band(s) of wrinkled or bunched stretch film advantageously
increase(s)
the tensile strength of the stretch film and render(s) the folded stretch film
less prone
to tearing during use, such as for example during wrapping of palletized loads
for
shipping, as compared to conventional stretch film.
1000631 Additionally, and as will be appreciated, the spacing of each
longitudinal band of wrinkled or bunched stretch film from the longitudinal
edge of
the folded stretch film advantageously allows the reinforcement to be
distributed
across a greater portion of the width of the film.
1000641 Although in the embodiment described above, each longitudinal band
of wrinkled or bunched stretch film web has a width of about 0.3 inches, in
other
CA 02856999 2014-07-16
- 13 -
embodiments, at least one longitudinal band may alternatively have a width in
the
range from about 0.0625 inches to about 4 inches. Still greater widths may be
used.
[00065] Although in embodiments described above, each longitudinal band of
wrinkled or bunched stretch film web is spaced from the nearest longitudinal
edge of
the folded stretch film web by at least a distance corresponding to the width
of the
longitudinal band, in other embodiments, at least one longitudinal band may
alternatively be spaced from the nearest longitudinal edge of the folded
stretch film
web by a distance of about 0.0625 inches or more.
[00066] It will be appreciated that, in other embodiments, and during use
of any
of the folding devices described above, different operating conditions may
result in
the formation of one or more bands of wrinkled or bunched film instead of one
or
more pleats.
[00067] The apparatus may have other configurations. For example, although
in the embodiment described above, the second intermediate roller is
configured to be
oscillated along an oscillation axis, in other embodiments, one or more of the
following may alternatively be configured to each be oscillated along a
respective
oscillation axis: the folding device; the first intermediate roller; the
second
intermediate roller; the roller adjacent the winding shaft; and the winding
shaft. For
example, in one such alternative embodiment, the winding shaft inay be
configured to
be oscillated along an oscillation axis, while the other rollers and
components of the
apparatus may be configured to not be oscillated. In still other embodiments,
the
apparatus may alternatively comprise one or more additional guides separate
from the
folding device that are configured to be oscillated along a respective
oscillation axis
for oscillating the folded stretch film web.
1000681 Although in the embodiment described above, the second intermediate
roller is oscillated over a fixed distance along the oscillation axis, in
other
embodiments, the second intermediate roller may alternatively be oscillated
over a
variable distance along the oscillation axis, such as for example, a
periodically
variable distance or a random distance.
[00069] Although in the embodiment described above, the second intermediate
roller is oscillated over a fixed distance along the oscillation axis, in
other
embodiments, the second intermediate roller may alternatively be oscillated
over a
CA 02856999 2014-07-16
- 14 -
variable distance along the oscillation axis, such as for example, a
periodically
variable distance or a random distance.
[00070] Although in the embodiment described above, the fixed frequency is
a
frequency in the range from about 0.1 cycles per minute to about 200 cycles
per
minute, in other embodiments, the fixed frequency may alternatively be a
frequency
that is greater than 200 cycles per minute.
[00071] Although in the embodiment described above, the fixed distance is a
distance in the range from about 0.1 inches to about 4 inches, in other
embodiments,
the fixed frequency may alternatively be a distance that is greater than 4
inches.
[000721 Although in the embodiment described above, the oscillation axis of
the second intermediate roller is generally orthogonal to the direction of
travel of the
folded stretch film web, in other embodiments, the oscillation axis of the
cutting
station and the cutting blades may alternatively be non-orthogonal to the
direction of
travel of the folded stretch film web.
[00073] Although in the embodiment described above, the first intermcdiate
roller and the second intermediate roller are configured as idler rollers, in
other
embodiments, one or both of the first intermediate roller and the second
intermediate
roller may alternatively be configured as a driven roller.
[00074] Although in the embodiment described above, the apparatus comprises
a first intermediate roller and a second intermediate roller, in other
embodiments, the
apparatus may alternatively comprise fewer or more intermediate rollers. In
one
embodiment, the apparatus may alternatively comprise no intermediate rollers.
[000751 Although in the embodiment described above, the apparatus comprises
a winding shaft supporting a core, in other embodiments, the apparatus may
alternatively comprise a coreless winding shaft that does not support a core,
onto
which the oscillated folded stretch film web is wound so as form a coreless
roll of
folded stretch film.
1000761 Although in the embodiment described above, the roller adjacent the
winding shaft is configured as an idler roller, in other embodiments, the
roller
adjacent the winding shaft may alternatively be configured as a driven roller.
In one
such embodiment, the surface speed of the driven roller may bc matched to thc
surface speed of the wound film on the winding shaft using automated or
computer-
CA 02856999 2014-07-1.6
- 15 -
controlled speed matching. In another such embodiment, there may be no
assembly
provided for rotatably driving the winding shaft, and the winding shaft may
alternatively be driven through contact with the surface of the driven roller.
1000771 Those skilled in the art will appreciate that the apparatus is not
limited
to the components described above. For example, in other embodiments, one or
more
of the first intermediate roller, the second intermediate roller, and the
roller adjacent
the winding shaft, may alternatively not be provided.
1000781 Other apparatus configurations are possible. For example, although
in
the embodiment described above, the apparatus comprises an extruder and a
rotating
cast roller for forming the stretch film web, in other embodiments, the
apparatus may
alternatively not comprise an extruder and a cast roller for forming the
stretch film
web, but may alternatively comprise a supply (e.g. a spool, a roll, etc.) of
previously-
fabricated stretch film web, and provisions for feeding the stretch film web
from the
supply either directly or indirectly to the folding device. It will be
understood that
such a configuration would provide an "off-line" or "secondary" apparatus for
fabricating the stretch film roll, and namely the roll of folded stretch film.
Those
skilled in the art will recognize that such previously-fabricated stretch film
webs may
otherwise typically be used for other "off-line" or "secondary" processes such
as, for
example, one or more of: conventional rewinding, slitting, pre-stretching, and
edge
folding/rolling.
1000791 For example, Figure 16 shows another embodiment of a folded stretch
film web formed using another embodiment of an apparatus (not shown), and
which is
generally indicated by reference numeral 550. Folded stretch film web 550 is
formed
using a secondary apparatus (not shown) for fabricating a stretch film roll.
In this
embodiment, the secondary apparatus comprises a supply (e.g. a spool, a roll,
etc.) of
previously-fabricated stretch film web, and provisions (not shown) for feeding
the
stretch film web from the supply (not shown) to the downstream portion of the
secondary apparatus. The secondary apparatus also comprises an edge rolling
device
(not shown) configured to roll the edges of the stretch film web, so as to
form edge
rolls 586. Each edge roll 586 comprises a rolled, generally wrinkled or
bunched
portion of stretch film web extending the length of an edge of the stretch
film web.
CA 02856999 2014-07-16
- 16 -
Edge rolling devices configured to form edge rolls have been previously
described,
for example, in U.S. Patent No. 5,531,393 to Salzsauler et al.
[000801 The secondary apparatus further comprises a folding device (not
shown) positioned downstream from the edge rolling device. The folding device
is
similar to folding device 130 described above and with reference to Figures 5
to 7, but
comprises a form (not shown) having only two (2) inner channels (not shown).
The
folding device of this embodiment also comprises two (2) inner guides (not
shown),
each sized to engage a respective channel. In this embodiment, the folding
device is
configured to form a folded stretch film web 550 comprising two (2)
longitudinal
bands 454 of wrinkled or bunched stretch film web, in a similar manner as
longitudinal bands 454 described above and with reference to Figure 15. Each
longitudinal band 454 comprises a wrinkled or bunched portion of stretch film
web
that has increased thickness and that comprises a plurality of longitudinal
folds. Each
longitudinal band 454 is spaced from the nearest longitudinal edge of the
folded
stretch film web. Further, each longitudinal band 454 is spaced from the
nearest edge
roll 586 of the folded stretch film web 450 by at least a distance
corresponding to the
width of the longitudinal band. In this embodiment, each longitudinal band 454
has a
width of about 0.3 inches.
[00081[ In this embodiment, the secondary apparatus further comprises one
or
more oscillating members (not shown) configured to yield an oscillated, folded
stretch
film web 550, and a winding shaft (not shown) for winding the oscillated
folded
stretch film web 550 to form a stretch film roll, and namely a roll of folded
stretch
film comprising two (2) longitudinal bands 454 of wrinkled or bunched stretch
film
web and two (2) edge rolls 586, as shown in Figure 16.
1000821 Although in the embodiment described above, the edge rolling device
is positioned upstream from the folding device, in other embodiments, the edge
rolling device may alternatively be positioned downstream from the folding
device.
[00083] Although in the embodiment described above, the secondary apparatus
also comprises an edge rolling device configured to roll the edges of the
stretch film
web, in other embodiments, the secondary apparatus may alternatively comprise
an
edge folding device configured to fold the edges of the stretch film web.
CA 02856999 2014-07-16
- 17 -
[00084] Although in the embodiment described above, each longitudinal band
of wrinkled or bunched stretch film web has a width of about 0.3 inches, in
other
embodiments, at least one longitudinal band may alternatively have a width in
the
range from about 0.0625 inches to about 4 inches. Still greater widths may be
used.
[00085] Although in embodiments described above, each longitudinal band of
wrinkled or bunched stretch film web is spaced from the nearest edge roll of
the
folded stretch film web by at least a distance corresponding to the width of
the
longitudinal band, in other embodiments, at least one longitudinal band may
alternatively be spaced from the nearest edge roll of the folded stretch film
web by a
distance of about 0.0625 inches or more.
[00086] In other embodiments, different operating conditions may result in
the
formation of one or more pleats instead of one or more of longitudinal bands
of
wrinkled or bunched stretch film web.
[00087] It will be appreciated that the stretch film roll, and namely the
roll of
folded stretch film in accordance with the above-described embodiments, may
therefore comprise: one or more pleats and/or one or more longitudinal bands
of
wrinkled or bunched stretch film web, in any combination, and may optionally
comprise edge rolls or edge folds, and may be fabricated using an "offline" or
"secondary" apparatus, or using a "non-offline" or "non-secondary" apparatus.
[00088] Although embodiments have been described above with reference to
the accompanying drawings, those of skill in the art will appreciate that
variations and
modifications may be made without departing from the scope thereof as defined
by
the appended claims.
