Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02488661 2004-11-29
ROLL WRAP CRIMPER
FIELD OF THE INVENTION
[0001] The present invention relates generally to roll wrap crimpers. More
particularly, the present invention relates to a crimper and method for
crimping roll wrap
overhang on paper rolls.
BACKGROUND OF THE INVENTION
[0002] For many decades, paper companies have wrapped their product rolls
(such
as paper rolls and other packages) in heavy kraft paper or other flexible and
durable
materials to protect them from damage in transit or storage. The process of
wrapping the
package generally consists of placing a covering of this material (called
"roll wrap" which is
derived from a "wrapper stock") around the circumference of the paper roll
(also called a
"bilge"), attaching an inner protective disc ("inner head") of heavy paper,
chip board or
corrugated medium against each paper roll end, crimping the excess roll wrap
against the
ends of the paper roll or inner head, and gluing/sealing an outer protective
disc of heavy
paper ("outer head") on to the crimped roll wrap and/or the inner head.
[0003) The roll wrap is typically selected from the available widths of
wrapper stock in
unwind stands ("backstands") used in the wrapping facility, and is usually
substantially wider
than the paper roll. The extra width, called the wrap overhang, is distributed
more or less
equally at each end of the paper roll, and ultimately forms the crimped
portion of the
package. In small manual wrapper systems, crimping is usually done by hand. In
automated
wrapping systems, individual paper rolls are typically transferred to wrapping
platforms on
which they are wrapped by roll wrap.
(0004] Wrapper stock is stored in the form of rolls of varying widths in the
wrapping
system. Each individual width is in its own backstand. In automated wrapping
systems, the
diameter and width of each incoming paper roll is measured by a control
system. This
system selects the best wrapper stock width from the available choices and
calculates what
length of wrapper must be provided to the given paper roll diameter to give
the number of
wrapper convolutions of wrapper required by the client. Depending on the needs
of the client
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and the availability of particular widths of wrapper stock, the wrapper may or
may not be
optimal for the width of the roll.
[0005] In automatic wrapping systems, the wrapper stock is fed close to the
paper
roll, and glue is applied to the leading edge. The wrapper stock is advanced
until it is
pinched between the paper roll and a set of turning platform rollers on which
the paper roll is
resting. The platform rollers are actuated at the same speed as the wrapper
stock supply
speed and the wrapper stock is pinched between the paper roll and the turning
rollers. The
wrapper stock adheres to the paper roll and is carried around the paper roll
until the correct
number of convolutions has been applied. The system is stopped, the wrapper
stock is
severed and, simultaneously, a strip of glue is applied to the tail end of the
roll wrap derived
from the wrapper stock.
[0006] The platform rollers are restarted, drawing the tail end into a pinch
point
causing the tail of the roll wrap to adhere to the convolutions already
applied. At this point,
the roll wrap overhangs the paper roll ends forming a large "tube". The length
of the
overhang depends on the width of the wrapper stock used and the length of the
paper roll to
be wrapped. After inner heads are inserted and retained at the ends of the
paper roll, the
wrap overhang is crimped.
[0007] As is understood in the art, crimping of the wrap overhang typically
involves
folding down the ends of the roll wrap towards the end of the paper roll.
Crimping can also
include creasing the folded wrap overhang to maintain the folds on the end of
the paper roll.
This extra step helps to prevent the folded material from "springing" back up
away from the
end of the paper roll. Depending on the flexibility of the roll wrap material
to be crimped and
the number of layers in the wrap overhang, folding alone may not be sufficient
to ensure an
effectively crimped package.
[0008] The crimped wrap overhang serves two functions. It provides a surface
against which the outside head is placed and sealed to complete a package.
Additionally,
after the package is complete, the crimped wrap overhang provides a protective
buffer inside
the package between the end of the paper roll and the floor when the paper
roll is stored on
its end. It is essential to create a "regular" or successfully crimped wrap
overhang. The
more regular the crimp, the more effective the crimped material acts as a
cushion and
protection for the end of the paper roll.
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[0009] Current practice usually involves the use of crimping wheels which
engage the
wrap overhang while in rotation. A typical crimper wheel consists of a disc
having a number
(typically 4 to 6) of crimping paddles or blocks. The disc is usually mounted
on the end of a
drive shaft which rotates the crimper wheel. The drive shaft is supported by a
pivot arm,
which holds the drive shaft at one end to lift and lower the crimper wheel
relative to the wrap
overhang. When the crimper wheel is lowered into a crimping position, the
paper roll is also
caused to rotate. During this process, wrap overhang is "slapped" by the
crimping blocks,
pushing the wrap overhang towards the centre of the roll end. As the paper
roll is rotated,
new wrap overhang is continuously presented to the crimper. This continues
until the entire
wrap overhang has been crimped.
[0010] Crimpers of the above-mentioned type are well known in the prior art,
and are
typically incorporated into standard paper roll packaging assembly stations.
US Patent No.
5,642,600, issued to Hooper et al., discloses an apparatus for wrapping,
crimping and plating
a wrapped roll at a single station. The crimper includes a plurality of
crimper paddles that
slide against the overhanging wrapper to fold it to the roll end when the
crimper paddles are
rotated as a unit about a horizontal axis. Similar crimpers of this sort in
the package
wrapping industry are shown in US Patent No. 6,678,928, issued to Wallace, and
US Patent
No. 6,381,921, issued to Tale' et al.
[0011] There exist certain problems with these °paddle-type" crimpers.
Determining
optimal crimping block/paddle geometry has traditionally been arbitrary, left
in the hands of
skilled professionals who have selected the shapes and number of blocks based
on their
own personal experience with the crimper. A scientific approach to crimper
design is largely
unknown and daunting, considering the number of dynamic variables to be
considered,
including the optimal width of the block, the rotational speed of the crimping
wheel, and the
thickness of the wrap overhang. Because of the apparent lack of crimper design
standards,
it has been difficult to efficiently achieve uniform and effective crimping of
wrap overhang of
different materials and sizes. Many of the crimpers currently in operation are
ineffective in
producing a stable, effective crimp. These crimpers merely fold the wrap
overhang on the
ends of the paper roll without creasing the folds that are generated.
Consequently, there is
an increased risk for damage to the paper rolls resulting from improper
packaging.
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[0012] Current technology has been most successful in producing crimps with 4~
of
wrap overhang. For wider wrap overhangs, the quality of the crimping
diminishes. While
typical crimps produced with 4-6" of wrap overhang are acceptable, poor
results are
achieved when the wrap overhang exceeds 6". With a wide range of paper roll
widths to
wrap, and the limited choice of wrapper stock widths in most packaging
factories to meet the
needs of discriminating clientele, it is inevitable that the lengths of
certain wrap overhangs
will be outside the optimum range for crimping. With poor crimping comes non-
uniform crimp
pitch, wrinkling and bunching of the roll wrap. Thus, there is a need tv
prevent undesirable
results when crimping wrap overhang longer than about 6".
[0013] There also exist problems when current crimpers are used with heavier
wrapping material, such as heavy kraft paper. The problems arise in situations
of increased
friction between the crimper blocks and the wrap overhang. It has been found
that abrupt
engagement of current crimpers and the wrap overhang contributes to an
irregular crimp
pitch, leading to wrinkling and unwanted creasing of the wrap overhang. This
is undesirable,
as an improperly crimped wrap overhang can allow the contents of the paper
roll to be
exposed to the elements, such as moisture and dirt. Also, an outer head cannot
properly
adhere to the end of the paper roll. This can result in damage to the paper
roll when the
paper roll is positioned on end (as is commonly done in paper roll storage
facilities).
[0014] To reduce friction, freely-rotatable crease rollers have been used in
the
wrapping industry as well as many other related industries. Crease rollers of
this type
appear in several prior art crimper systems. US Patent No. 3,924,375, issued
to Brenner et
al., discloses a crimping device for crimping the projecting ends of dual-wrap
paper wrapped
around the circumference of a roll. The device comprises a displacement member
for
starting displacement of the projecting wrapper ends, a tucking member which
operates after
the displacement member to tuck the displaced ends toward the roll end, and a
rolling
member following the tucking member for rolling the tucks into flat successive
crimps against
the roll ends. The three members are mounted to a swinging arm which engages
the
members into a crimping position against the roll. The crimping action takes
place along the
circumference of the roll end. A problem with this arrangement is evident in,
for example,
Figure 6 of Brenner et al. There is an increased risk for wrinkling and
improper creasing of
the wrap overhang, since the folds must align properly to ensure a smooth
crimp.
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(0015] US Patent No. 5,907,941, issued to Fukuzumi et al., describes a film
roll
wrapping apparatus comprising a folding unit for folding a protruding part of
a photographic
film roll. Folding blades abut against protruding parts and fold them down
onto the end face
of the photographic film roll. As the roll is rotated, the folded wrap is heat-
sealed to the end
of the roll by a heating roller, followed by a cooling roller. Both rollers
are positioned along
the circumference of the roll.
(0016] US Patent No. 4,845,919 discloses an apparatus for folding and pleating
"ears" of packaging material wrapped around a cylindrical article. A bending
guide is
pressed against the side surface of a roll and a folding unit (comprising a
pressing device, a
folding roll and a folding claw) swings to press the ear of the packaging
material. As the
folding unit and the roll rotate relative to each other, a folding claw is
engaged to fold in the
pressed ears.
[0017] US Patent No. 5,174,095 discloses a device for packaging a rolled web
comprising a feed roller which rolls in the direction of the rotating rolled
web, a rotating
folding member (truncated cone rotating opposite to the direction of the web
roll), and a fold-
keeping plate for holding the folded sections toward the web roll.
[0018] In the above-described crimpers, and other known devices having a crimp-
roller mechanism, the crease rollers typically serve to crease (or press down
to keep folded)
wrap overhangs along the circumference of the roll end. This can be
potentially
disadvantageous, considering the rapid crimping required in high-throughput
operations.
Bunching of the wrap ovefiang can occur, particularly at the beginning and end
of the
crimping action. This results in less-than-optimal crimping and packaging of
the paper roll,
decreasing efficiency and adding unnecessary expanse to the operation.
[0019] It is, therefore, desirable to provide a crimper and method of crimping
that
reduces the occurrence of poor quality crimps and is especially suitable for
crimping wrap
overhangs of more than 6 inches.
SUMMARY OF THE INVENTION
[0020] It is an object of the present invention to obviate or mitigate at
least one
disadvantage of previous roll wrap crimpers and crimping methods.
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[0021] In a first aspect, the present invention provides a crimper for
crimping flexible
material comprising a rotatable support for mounting to a drive shaft, for
rotation about a
support axis, a folding member on the support for engaging and bending the
flexible material
to generate a fold upon rotation of the support and a crease roller on the
support in direction
of rotation behind the folding member for creasing the fold upon rotation of
the support, the
crease roller having a roller axis extending perpendicular to the support
axis.
[0022] In one embodiment of the present invention, the support comprises at
least
one arm disposed perpendicularly to support axis. A preferred embodiment is a
support
having four arms in the shape of a cruciform with a folding member and crease
roller
mounted to each arm.
[0023] Using a freely turning crease roller on the crimper considerably
reduces
friction between the roll wrap and the crimper, substantially eliminating
wrinkles and tears in
the wrap overhang.
[0024] In addition, it has surprisingly been found that the folding member and
creasing roller tandem of the present invention is ideally suited for folding
down longer wrap
overhangs, particularly those over 6 inches in length. This feature allows the
crimper of the
present invention to successfully fold wrap overhangs which are too wide for
current
crimpers.
[0025] In another aspect of the present invention there is provided a method
of
crimping wrap overhang on a paper roll having a paper roll axis and an end
face, comprising
the steps of forcing a portion of the wrap overhang towards the paper roll
axis for generating
a fold in the wrap overhang and creasing the fold against the end face with a
creasing
member moving in a tangential arc over the end face.
[0026] Surprisingly, it has been found that the unified sweeping motion
provided by
the successive tandem combination of a folding member and a creasing member
(such as a
crease roller) on a single rotating support which forces the wrap overhang
inward toward the
centre of the roll end, is effective in generating more regular crimps. By
folding and creasing
the wrap overhang in a tangential arc over the roll end, rather than "pushing"
it along the
circumference of the roll, the wrap overhang is more effectively folded and
creased.
[0027] In another aspect of the present invention there is provided a crimper
assembly comprising a platform for receiving an item to be crimped, a
pivotable arm
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mounted on the platform, a motorized drive shaft mounted on an end of the
pivotable arm,
and the crimper as described herein.
[0028] Other aspects and features of the present invention will become
apparent to
those ordinarily skilled in the art upon review of the following description
of specific
embodiments of the invention in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Embodiments of the present invention will now be described, by way of
example only and with reference to the attached Figures, wherein:
Fig. 1 shows a front view of the crimper of the present invention mounted to a
standard pivot arm used in packaging assemblies.
Fig. 2 shows an isolated front perspective view of the crimper of the present
invention.
Fig. 3 shows an isolated rear view of the crimper of the present invention.
Fig. 4 shows a crimper of the present invention in the operation of crimping
roll
wrap overhang.
DETAILED DESCRIPTION
[0030] Generally, the present invention provides a crimper and method of
crimping
roll wrap overhang. In one aspect, the present invention provides a crimper
for crimping
flexible material comprising a rotatable support for mounting to a drive
shaft, for rotation
about a support axis, a folding member on the support for engaging and bending
the flexible
material to generate a fold upon rotation of the support and a crease roller
on the support in
direction of rotation behind the folding member for creasing the fold upon
rotation of the
support, the crease roller having a roller axis extending perpendicular to the
support axis.
[0031] Preferably, the crimper is used in the packaging of web rolls, such as
paper
rolls and the like. Typically, the crimper of the present invention is used
with current paper
roll packaging systems. Alternatively, the crimper can form part of a stand-
alone integrated
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paper roll packaging system. The crimper is especially suited to crimping wrap
overhang of
protective and flexible roll wrap (such as kraft paper) at the ends of the
rolls, thus readying
the package for the placement of an outside head, if necessary, and eventual
storage and
transportation of the roll.
[0032] The crimper of the present invention comprises a rotatable support, a
folding
member and a crease roller. Embodiments of the rotatable support include
crimping
"wheels", as shown in the Figures. Figure 1 illustrates one embodiment of a
crimper of the
present invention mounted to a typical drive shaft and pivot arm. The drive
shafts used with
the present invention are known in the art and extend from pivoting lift-and-
lower arms which
place the crimper in proximity with an end of the paper roll and wrap overhang
thereon. A
main drive shaft extending outward from pivot arm 14 is attached to a crimper
at a central
location 32 of the rotatable support. The crimper is rotatable about the
longitudinal axis of
the drive shaft. which forms the support axis.
[0033] The rotatable support is typically a member of any shape or length
including,
for example, a block, rod, or ring, and made of a durable material such as
steel, for
supporting the folding member and the crease roller. The rotatable support can
be mounted
on the main drive shaft of standard crimping apparatuses. In the embodiments
shown
particularly in Figures 3 and 4, the rotatable support has one or more arms 30
which extend
perpendicularly from a central location 32 on the rotatabie support. In this
embodiment, the
rotatable support is substantially cruciform in shape and has four equally
spaced arms 30a,
30b, 30c and 30d, of approximately the same length.
[0034] A folding member 28, as shown mounted on the rotatable support
illustrated in
the Figures, is preferably made of any rigid material, such as metal, and is
sturdy enough to
fold the wrap overhang of any typical roll wrap material, such as kraft paper
and the like.
Additionally, the folding member 28 should be able to effectively fold down
one or more
layers of wrap overhang. The embodiment described herein has been used
successfully to
fold at least 10 layers of kraft paper wrap overhang. The folding member 28 is
typically
mounted on each arm 30 of the rotatable support. The folding member 28 can be
any width
or thickness, and is interchangeable with other folding members as needed for
a particular
crimping task. The folding member 28 can either be slidable or fixedly
positioned according
to the needs of the user. In certain embodiments of the crimper of the present
invention, the
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folding member 28 can be adjustable radially from a central location 32 on the
rotatable
support and/or along an arm 30. A crimper using the folding member 28
described
substantially herein is particularly suitable for wrap overhangs greater than
4 inches in length
and, unlike crimpers known and used in the art, can be used for crimping wrap
overhangs of
6 inches or greater.
[0035] As shown in Figures 2, 3 and 4, folding members used in the present
invention are curved inward, away from the leading edge of an arm 30 (i.e.,
the edge facing
the wrap overhang 17 to be crimped at an end of the paper roll). 1n this way,
wrap overhang
17 is less likely to be damaged by a free end 34 of the folding member 28,
since this free end
34 typically points away from, and does not touch, the wrap overhang 17 when
the crimper is
rotated about the drive shaft 10. However, a substantially planar member could
also be used
as a folding member, though the crimping results are likely to be less than
optimal.
[0036] Mounted in tandem on the rotatable support in the direction of rotation
behind
the folding member is a crease roller. In the embodiment shown particularly in
Figures 3
and 4, a roller shaft 22 machined to an arm 30 accepts a crease roller 24
which freely rotates
about the roller shaft 22. Each crease roller 24 is mounted on ball bearings
(not shown) on
the roller shaft 22. The crease roller 24 serves to crease the folds made by
the folding
member 28. A cap 26 is placed at the end of the crease roller 24 to provide a
smooth end on
the crease roller, thus protecting the wrap overhang from damage when the
crease roller 24
strikes the wrap overhang. In Figure 3, the arrow shows the direction of
rotation of the
crimper.
[0037] The crease roller 24 is mounted on the arm 30 such that its rolling
face
extends outward from the arm 30 and/or the folding member 28. This ensures
that the
crease roller 24 performs the creasing with minimum friction between the wrap
overhang 17
and the rotatable support. Optimally, the rolling face of the crease roller 24
should extend
beyond the arm 30 and/or the folding member 28 by a distance of approximately
0.16 inches
(approximately 4.064 mm), but this distance can be varied by the user
depending on the
material to be crimped.
(0038] Optionally, a face plate can be added to the crimper of the present
invention.
In the embodiment shown in Figures 1 and 2, a face plate 20 is affixed to the
rotatable
support, typically on an edge of the arms 30 facing the wrap overhang to be
crimped. The
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face plate 20 can be any metal disc or other sturdy disc. The face plate 20
provides a
durable flat surface for ensuring optimal crimping of the wrap overhang 17. It
can also be
used as a means for correcting any misalignment between the crimper and an end
of the
paper roll when the pivot arm 14 is lowered into the crimping position (see
Figure 4). When
a face plate is used, a rolling face of the crease roller 24 should extend
outward from the
face plate by at least the same distance described above.
[0039] Optionally, and as shown in Figure 2 in particular, the crimper of the
present
invention has a filler plate 40 mounted on to the rotatable support, either to
an arm 30 or a
face plate 20, depending on the embodiment used. The filler plate 40 serves to
maintain the
crease generated by the creasing roller, preventing the wrap overhang 17 from
"springing
out" before the wrap overhang 17 comes into contact with the next folding
member 28 and
crease roller 24 tandem, thus reducing instances of improper crimping. The
filler plate 40
can be any shape, but is typically scimitar or arcuate in shape in keeping
with the rotational
motion of the crimper. The filler plate 40 should permit sufficient clearance
between
successive folding members 28 for accessing wrap overhang 17 which is
presented to the
crimper for crimping, when more than one folding member 28 is used.
[0040] Optionally, a spring is used with the crimper described herein. As
shown in
Figure 4, the spring 18 mounts on the end of a standard main drive shaft
interposed
between a collar of the drive shaft 10 onto which a retention nut 16 is
secured, and the
crimper at the second end of the drive shaft. The spring 18 provides two
functions. First, it
allows for misalignment between the crimper and the end 21 of the paper roll
13 when the
pivot arm 14 bearing the crimper is lowered into the crimping position.
Second, it stabilizes
the crimper to provide a uniform axial load from the crimper to the end 21 of
the paper roll 13
regardless of any variations in the flexible material to be crimped. It
provides constant
pressure between the crimper and the flexible material.
[0041] In another aspect of the present invention there is provided a method
of
crimping wrap overhang on a paper roll having a paper roll axis and an end
face, comprising
the steps of forcing a portion of the wrap overhang towards the paper roll
axis for generating
a fold in the wrap overhang and creasing the fold against the end face with a
creasing
member moving in a tangential arc over the end face. In this method, a unified
sweeping
motion is provided by the tandem combination of a folding member (which forces
a portion of
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the wrap ovefiang towards the paper roll axis and generates a fold in the wrap
overhang)
and creasing member (such as the creasing roller described above) on a single
rotating
support. The folding and creasing of the wrap overhang in a tangential arc
over the roll end
generates more regular crimps on the end of the paper roll than is typically
achieved with
standard crimpers. Consequently, folding and creasing of the wrap overhang is
achieved
more effectively than other systems which "push" the wrap overhang along the
circumference
of the roll.
[0042] Figure 4 illustrates the crimper of the present invention in operation.
After roll
wrap has bean applied to the paper roll 13, a control system effectuates a
pivot arm 14 by
lowering it into a crimping position, wherein the crimper is adjacent to the
wrap overhang 17
at the end of the paper roll 13. Platform rollers (not shown), on to which the
wrapped paper
roll rests, are activated and the wrapped paper roll 13 starts to turn at a
selected rotational
rate. The crimper, mounted on drive shaft 10 powered by a drive gear box 15,
is also caused
to rotate, turning at a pre-selected rate.
(0043] The pivot arm 14 is then lowered and the crimper begins to engage the
wrap
overhang 17. The folding member 28 meets the wrap overhang 17 first and begins
the
crimping action by deflecting and folding the wrap overhang 17 downwards
towards a central
region 21 on the end of the paper roll 13. The crease roller 24 then engages
the wrap
overhang 17 and completes the crimping action by rolling over and creasing the
folds 23
created by the folding member 28. The crimping process continues until the
entire wrap
overhang 17 has been crimped. At this time, the rotation of the crimper is
stopped and the
pivot arm 14 raises the crimper from its crimping position. An outside head
(not shown) is
affixed onto the crimped end of the paper roll to complete the packaging of
the paper roll 13
and to prepare it for transportation and/or storage.
(0044] The tandem action of the folding member 28 and the crease roller 24 in
one
crimper has been shown to be more effective in crimping wrap overhang. Unlike
current
crimper wheels having a series of paddles which merely "slap" the wrap
overhang, the
crimper of the present invention combines two distinct features of crimping,
namely folding
and creasing. The crease roller 24 creases the wrap overhang 17 folded by the
folding
member 28, resulting in a complete crimp.
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[0045] Additionally, and unlike current crimpers which use a folding mechanism
and a
roller along the circumference of the end of the roll ("fold-roller"
crimpers), the crimper of the
present invention provides a method of crimping wrap overhang in one sweeping
rotating
motion. Through the rotational movement of the crimper, the folding member 28
folds the
wrap overhang 17 on the end face of the paper roll towards the paper roll axis
while the
crease roller 24 follows in the same direction of rotation, creasing the folds
made by the
folding member 28. This action reduces the risk of "bunching" the wrap
overhang 17 typically
found with circumferential fold-roller crimpers, and generates more effective
crimps.
[0046] The above-described embodiments of the present invention are intended
to be
examples only. Alterations, modifications and variations may be effected to
the particular
embodiments by those of skill in the art without departing from the scope of
the invention,
which is defined solely by the claims appended hereto.
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