Note: Descriptions are shown in the official language in which they were submitted.
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"COMPACT REWINDER FOR FORMING ROLLS OF WOUND-UP WEBLIKE
MATERIAL AND ASSOCIATED METHOD"
DESCRIPTION
Technical field
The present invention relates to a rewinding machine for the
production of rolls of wound-up weblike material, for example rolls intended
for the production of small rolls of toilet paper, kitchen towel and the like.
In particular, but not exclusively, the invention relates to a rewinder of
the peripheral or superficial type, that is to say one in which the roll or
log
being formed is retained in rotation in a winding-up cradle by means of
winding-up members which are in contact with the roll being formed over its
peripheral surface, transmitting thereto the rotational winding-up movement.
The invention also relates to a winding method which can be
implemented on the abovementioned rewinder.
State of the art
in the paper converting industry, use is frequently made of machines
known as winders or rewinders, which receive an incoming weblike material
coming from a parent reel or plurality of parent reels, to wind it up in the
form
of rolls or logs of diameter equal to the diameter of the finished product and
great length. These rolls or logs are subsequently cut orthogonally to their
axis to form small rolls of toilet paper, kitchen towel and the like.
Machines of this type, based on the peripheral winding-up procedure,
are described and illustrated, for example, in: US-A-4 723 724, US-A-
4 856 725, US-A-4 828 195, US-A-4 962 897, US-A-4 487 377,
US-A-4 931 130, US-A-5 248 106, US-A-5 368 252, GB-A-2 105 688, WO-A-
94/21 545. Machines based on the central or mandrel winding-up procedure
are described in US-Re-28 353, US-A-3 532 572, US-A-3 552 670,
US-A-3 567 552, US-A-3 734 423.
The rewinding machines are normally designed on a large scale and
operate at very high speeds. In particular, the present trend is toward
producing rewinding machines suitable for processing weblike material of
ever-increasing width.
In some applications, however, it would be appropriate to have
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rewindina machines of modest size available, in particular to meet the r7eeds
of emerging markets where high production speeds are not necessary.
To meet these needs, a peripheral rewinding machine of particularly
modest size has been developed and is described in WO-A-97/32 804. This
rewinding machine provides a special winding-up system, with means of
gluing the final free edge of the roll located downstream of the winding-up
cradle. Normally, the unloading of the finished log and its gluing require a
cyclical slowing of the production line in order to obtain correct positioning
of
the free edge of the weblike material to be glued in order to seal the roll.
Objects and brief description of the invention
!t is an object of the present invention to provide a machine, especially
but not exclusively of the peripheral or superficial type, of modest size, and
therefore particularly easy to transport and such as to take up little space
when in use.
According to a particular aspect, it is also an object of the invention to
produce a compact machine in which the feed speed of the weblike material
need not be reduced at the end of each winding-up cycle.
Substantially, these and other objects and advantages, which will be
clear to the person skilled in the art from reading the text that follows, are
achieved in a rewinding machine equipped with a winding-up system,
generally of the central or peripheral type, and with a system for severing
the
weblike material at the end of each winding-up cycle in order to generate a
final edge and an initial edge, wherein an adhesive applicator applies the
adhesive to the final free edge of each roll in a position upstream of the
roll in
the final phase of winding-up in the winding-up system.
Normally, contrary to what is envisaged by the present invention, the
adhesive for sealing the free edge is applied to the final edge or to the roll
downstream of the winding-up system, when the roll has been unloaded from
said system. For this purpose, suitable gluing machines are usually provided,
disposed in line with the rewinding machine, optionally with the interposition
of a storage unit. This makes the line complex and bulky.
According to the invention, conversely, the adhesive is applied to an
end portion of the weblike material before the latter is wound up onto the
roll
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and before the roll is unloaded from the winding-up system. This makes the
machine more compact and enables other advantages to be achieved, bf4hic"
will become clear in due course.
US-A-4 487 377 describes a system in which the adhesive is applied
to the final -edge of the weblike material before completion of the roll.
However, in this case, the adhesive is not applied by an applicator directly
onto the weblike material. To the contrary, it is delivered onto a winding-up
core and the latter, when it is inserted into the winding-up system, transfers
some of the adhesive applied thereto to the final edge in order to achieve
sealing thereof. This known solution has significant limitations.
Specifically, it is applicable only with special winding-up systems and
only with certain systems for severing the weblike material and introducing
new winding-up cores. Furthermore, it is not applicable in cases where the
winding-up takes place without a central core. It should also be borne in mind
that it is not always possible or appropriate to use the same adhesive for the
final free edge of a roll and to anchor the initial free edge to the winding-
up
core in order to initiate the winding-up of the subsequent roll.
These limitations are overcome by the present invention.
According to a particularly advantageous embodiment of the invention,
the adhesive is applied to the weblike material before the latter is cut, torn
or
otherwise severed by the severing system. This may take place, for example,
by disposing the adhesive applicator upstream of the severing system.
However, in principle, it would also be conceivable to dispose the adhesive
applicator downstream of the area in which the severing system acts or on
the severing system itself.
Although the winding-up system may be of any kind, including the
central type (i.e. the type in which the winding-up movement is imparted to
the roll by means of a central mandrel around which the material is wound
up), according to a particularly advantageous embodiment of the invention
the winding-up system comprises a peripheral winding-up cradle. In this case,
the adhesive applicator may be disposed upstream of the winding-up cradle,
Yor example facing one of the winding-up rolls which form part of said cradle.
By comparison also with the more compact rewinding machines
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cescribec in WO-A-97/32 804, the present invention provides the possibility
of a further reduction in the bulk of the machine and the possibility of
achieving a high level of reliability and precision in gluing, even without
temporary reductions of the feed speed of the weblike material.
Furthermore, it is possible to wind up even rolls of large diameter. This
is possible because, once the adhesive has been applied, before completion
of the winding-up of the final free edge of the roll, the latter performs a
rotation in the winding-up cradle and subsequently on an unloading surface
to exert pressure on the final free edge and stabilize the latter for gluing
to
the final turn of the roll. In practice, the roll may also perform a complete
revolution in the winding-up cradle before being unloaded, so that at the time
of unloading the final free edge has already been pressed against the last
turn of the roll.
!n the traditional systems, conversely, this operation requires -
especially in the case of rolls of large diameter - very long rolling surfaces
in
order to ensure that pressure is always exerted on the final free edge, and
hence large bulk.
In practice, the adhesive applicator may comprise one or more nozzles
disposed side by side to spray the necessary dose of adhesive onto the
weblike material. However, different systems for applying the adhesive, for
example a contact system with brush or pad members which touch the
weblike material, transferring the necessary adhesive thereto, are not ruled
out, although the use of nozzles is advantageous because it is simpler in
design and from the standpoint of maintenance and preparation, as well as
being more flexible.
In a practical embodiment, the winding-up cradle may possess a
winding-up system comprising a first winding-up roller and, optionally, a
second and a third winding-up roll, in accordance with a technology known
per se, although the possibility of a different configuration of the winding-
up
cradle is not excluded.
When at least a first winding-up roller is provided, the spray nozzle or
nozzles which apply the adhesive in order to seal the free edge of the weblike
material are disposed, relative to the first winding-up roll, in a manner such
as
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to spray the adhesive onto the weblike material when the latter is supported
~ moved arcund said winding-up roll. The means for severing the
weblike material are advantageously disposed downstream, in the direction of
movement of the weblike material, relative to the position of the spray
nozzles
which apply the adhesive.
The rewinding machine may be of the type which winds up onto
tubular cores, but the possibility is not excluded of applying the same
criterion
to rewinding machines which produce rolls of weblike material wound-up
without a central winding-up core, using known winding-up techniques
described, for example, in EP-A-0 580 561 and EP-A-0 611 723.
According to a further aspect of the present invention, a particular
configuration of an embossing and laminating unit is also proposed, of
particular compactness, capable of being inserted into a rewinding machine
of modest size. According to this aspect of the invention, the embossing unit
has a first and a second embossing cylinder and a first and a second
pressure roller, the embossing cylinders and the pressure rollers being
supported by the side frames which also support the perforating unit, the
winding-up cradle of the rewinding machine, particular compactness thereby
being achieved.
In practice, a reduction in bulk may advantageously be obtained by
placing the embossing cylinders one above the other vertically, in a manner
such that the first embossing cylinder is located above the second embossing
cylinder, for example and advantageously (but not necessarily) with the axes
placed one above the other in a vertical plane. In this case, the first
pressure
roller is positioned above the first embossing cylinder, while the second
pressure roller is disposed below the second embossing cylinder, but offset
laterally relative to the plane containing the axes of the embossing
cylinders,
which plane may advantageously and preferably (but not necessarily) be
approximately vertical. In this configuration, the winding-up cradle is
situated,
relative to the plane in which the axes of rotation of the embossing cylinders
lie, on the side opposite that on which the second pressure roller is located.
In this manner, as will become clear from the detailed description of an
example of embodiment, a configuration of particularly reduced size is
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achieved.
A system for combining the plies that constitute the weblike material
may be associated with the embossing unit. For example, a ply-bonding unit
may be provided. in an alternative embodiment, an adhesive dispenser may
be provided which, in a manner known per se, applies an adhesive to one of
the two plies of the weblike material, after the ply has been embossed. In
this
case, the adhesive dispenser is advantageously disposed above the second
pressure roller, again in order to obtain a very compact configuration. The
possibility of disposing both an adhesive dispenser and a ply-bonding unit in
the same machine, so as to permit the user to employ both methods, is not
excluded.
The invention also relates to a winding-up method for the production of
rolls of weblike material.
Further advantageous features of the machine and method according
to the invention are indicated in the attached claims.
Brief description of the drawings
The invention will be better understood by reference to the description
and the attached drawing, which shows a practical, nonlimiting example of
said invention. In the drawing:
Fig. 1 shows a lateral view of the rewinder according to the invention;
and
Figs. 2 to 4 show successive phases of the winding-up cycle.
Detailed description of the preferred embodiment of the invention
A detailed description will be given below of a particularly
advantageous embodiment of the invention, complete with accessories and
elements which may also, in part, be omitted. The embodiment illustrated is
of the type having tubular winding-up cores on which the individual rolls are
formed, but, as stated previously, the machine may also be designed for
winding-up without a tubular core.
The rewinder, generally designated 1, comprises side frames 3 on
which is mounted a winding-up cradle, generally designated 5, and
comprising in the example shown a trio of winding-up rollers 7, 9 and 11. The
first winding-up roller 7 forms, together with the second winding-up roller 9,
a
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gap 13 through which the weblike material and the roll pass at the start of
the
phase of formation around the respective winding-up core A.
The first winding-up roller 7 receives the weblike material N from an
unwinder (not shown). The third winding-up roller 11 is mounted on an arm
15 oscillating about an axis 17 in order to adapt to the increase in size of
the
roll being formed. Downstream of the winding-up cradle is disposed an
unloading chute 21 with a roll-stopping device 23 controlled by an actuator
25, which intervenes to stop the movement of the rolls and unload, in a
controlled manner, the individual rolls delivered to the winding-up cradle
aiong the chute 21.
Below the first winding-up roller 7 extends a curved rolling surface 25
along which the winding-up cores A roll in the first phase of winding-up of
the
weblike material N, in accordance with a technology known and described in
detail in WO-A-94/21 545, to which reference is made for more descriptive
details. Reference 27 designates an element for severing the weblike
material, which rotates in a controlled manner about an axis of rotation 29
and interacts with the first winding-up roller 7 to perform the severing of
the
weblike material at the end of the winding-up of each roll, so as to generate
a
final free edge, which is eventually wound onto the roll just completed, and
an
initial free edge which is caused to adhere to the next winding-up core.
The winding-up cores A are fed to the winding-up cradle 5 by means of
a feeder 31 which comprises a re-emergence guide for the cores A,
designated 33. The tubular cores A are inserted into the re-emergence guide
33 from below, sliding or rolling along a base surface 35 of a hopper 37 in
which is also located an agitator 39 that prevents the cores from becoming
jammed. The cores are unloaded individually onto the unloading surface 47
and retained in the waiting position by an elastic blade 49.
A rotating inserter 51, synchronized with the rotation of the severing
means 27, acts to push each tubular core A into the channel defined by the
rolling surface 25 and the first winding-up roller 7, at the start of each
winding-up operation.
Above the surface 47, in alignment with the holding position of the
cores A before insertion into the channel between the rolling surface 25 and
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irst winding-up roller 7, are disposed a plurality of first nozzles 53 which
apply to the temporarily waiting tubular core A the adhesive necessary fcr the
adhesion of the initial free edge of the weblike materiai. As an alternative
to
the gluing system, other systems may be used, for example suction or
electrostatic systems or others known in the art.
Along the path of the weblike material N coming from the unwinder
(not shown) is disposed an embossing and laminating unit generally
designated 61 and comprising a first embossing cylinder 63 rotating about an
axis of rotation 63A and a second embossing cylinder 65 rotating about an
axis of rotation 65A. The two embossing cylinders, made for example from
steel or another hard material, have surface tips or protuberances which
perform the embossing of the material.
Interacting with the first embossing cylinder 63, which is in a position
approximately vertically above the second embossing cylinder 65, is a first
pressure roller 67 supported by an arm 69 hinged at 71 and pressed against
the embossing cylinder 63 by means of an actuator 73. Interacting with the
second embossing cylinder 65 is a second pressure roller 75 supported by an
arm 77 hinged at 79 and pressed against the embossing cylinder 65 by
means of an actuator 81. As can be seen in Fig. 1, the three axes of rotation,
of the embossing cylinders and of the pressure roller 67, are approximately
vertically one above the other, in other words they lie in a common vertical
plane shown by the line P-P. Conversely, the axis of rotation of the pressure
roller 75 is offset and is located, relative to the plane in which the axes of
rotation 63A, 65A of the embossing cylinders 63, 65 lie, on the opposite side
from the winding-up cradle. A particularly compact configuration is thus
obtained.
The first and second embossing cylinders 63, 65 and the respective
pressure rollers 67 and 75 are supported by the same side frames 3 that
support the members forming the winding-up cradle.
Interacting with the first embossing cylinder 63 is an adhesive
dispenser 83, comprising in this example a distributor 85, a first screened
cylinder 87 and a second plate cylinder 89, in contact with the ply of
material
passed around the first embossing cylinder 63 in order to apply, in a manner
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known per se, an adhesive to the embossed protuberances of the ply
~rthe :u7'ace of the embossing cylinder 63. The adhesive
dispenser is located above the pressure roller 75.
Also interacting with the first embossing cylinder 63 is a coupling or
laminating roller 91 supported by an arm 93 hinged at 95 and stressed
against the embossing cylinder 63 by means of a piston-and-cylinder actuator
97. By means of this, the two plies, separately embossed on the two
embossing cylinders 63, 65, are coupled by lamination after the application of
the adhesive.
Two plies of weblike material, designated V1 and V2, are fed to the
embossing and laminating unit 61 and are embossed separately, the first
between the embossing cylinder 63 and the pressure roller 67 and the
second between the embossing cylinder 65 and the pressure roller 75. The
ply V2 is then detached from the second embossing cylinder 65 and placed
aently on the first ply V1 passed around the first embossing cylinder 63. The
two plies, thus placed one above the other, are laminated between the first
embossing cylinder 63 and the laminating roller 91 to form the weblike
material N. An application of adhesive being provided by the dispenser 83,
the lamination results in the two plies V1 and V2 being bonded one to the
other.
In the example of embodiment shown, there is provided along the path
of the weblike material N coming from the laminating/embossing unit 61 a ply-
bonding unit 101 comprising a cylinder 103 with which interact ply-bonding
rollers 105 stressed under pressure against the cylinder 103 by means of one
or more expansion boxes 107 which are expanded to high pressure. The ply -
bonding unit 101 may be used in addition to the embossing unit 61, for
example when the latter is operating without adhesive, because it lacks the
dispenser 83 or because the latter has been taken out of service. This does
not exclude the possibility that the machine lacks the embossing unit 61 and
is equipped only with the ply-bonding unit 101 which provides the coupling of
the two plies V1, V2, appropriately transported to the ply-bonding unit 101,
for
example by being passed around the roller 91. It is also possible to arrange
that the ply-bonding unit 101 is entirely absent and that the machine is
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suppiie: solely with the embossing and laminating unit 61, with the
associated adhesive dispenser 83. In this case, the path of the weblike
material N will be slightly modified.
Along the path of the weblike material N, between the ply-bonding unit
101 and the winding-up cradle 5, a perforating unit 111 is provided,
comprising a rotating blade-supporting roller 113 and a fixed roller 115
bearing a counter-blade. The perforating unit 111 may be of the traditional
type and is not described in detail.
The weblike material N which passes through the perforating unit 111
is provided with a series of perforation lines orthogonal to the longitudinal
course of the weblike material N, which perforation lines subdivide the
weblike material N into a series of slips or sheets for subsequent use by the
end consumer.
The perforated weblike material N coming from the perforating unit 111
is passed around a cylinder 117 and, from there, around the first winding-up
roller 7 in order to be passed to the winding-up cradle.
fnteracting with the first winding-up roller 7 is a series of spray nozzles
121 which serve to apply an adhesive to the weblike material N in order to
perform the sealing of the final free edge of the weblike material at the end
of
the winding-up of each individual roll, following the severing of the weblike
material by the severing member 27.
As clearly illustrated in Fig. 1, the nozzles 121 (which are provided in
appropriate numbers and suitably spaced to ensure correct gluing also of
areas over the length of the roll, in other words over the width of the
weblike
material) are disposed in a manner such as to spray the adhesive onto the
weblike material at the desired moment, before said weblike material passes
into the channel defined by the winding-up roller 7 and the rolling surface
25,
and thus before the member 27 for severing the weblike material acts upon it.
In this way, the adhesive, subsequently intended to seal the roll, is applied
to
the weblike material before the latter is severed.
cxpediently, the nozzles 121 may be mutually spaced relative to one
another in a manner such that the adhesive distributed thereby does not
affect those areas of the weblike material N with which the severing member
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2- iS, in contact, in a manner such that the latter does not become
contaminated with adhesive during each winding-up cycle.
More expediently, moreover, contamination of the severing member 27
by the adhesive sprayed by the nozzles 121 can be prevented with
appropriate timing of the actions of the two members. Specifically, as is
known from the prior art, the severing member 27 may be phased, relative to
the perforation lines produced by the perforating unit 115 on the weblike
material N, in a manner such that the weblike material is severed by tearing
at a position between the roll being wound up between the rollers 7, 9 and 11
and the point of contact between the severing member 27 and said weblike
material, in other words the point at which the weblike material is pinched
between the severing member 27 and the first winding-up roller 7. Since the
adhesive appiied by the nozzles 121 is to remain on the end part or tail of
the
weblike material which is being wound up on the roll being completed, the
spray nozzles 121, the perforator 111 and the severing member 27 may be
mutually phased in a manner such that the severing action performed by the
severing member 27 on the weblike material takes place when the perforation
along which the weblike material parts as a result of the pinching action of
the
severing member 27 is located at a sufficient distance from the area of action
of said member 27, so that the adhesive previously sprayed by the nozzles
121 onto the weblike material is reliably outside the area of contact between
the weblike material and the severing member 27.
While the foregoing has provided a description of the possibility of
using a series of spray nozzles 53 to apply an adhesive to the tubular cores A
before the latter are inserted between the rolling surface 25 and the winding-
f ip roller 7, this does not exclude the possibility that the adhesive
necessary
for anchoring the initial free edge of the weblike material to the winding-up
core A is applied by said nozzles 121. To this end, provision may be made for
the latter to be actuated twice, once in order to apply the adhesive to the
area
of weblike material N which, after the severing performed by the severing
member 27, will form the tail or final end of the roll, and a second time to
the
weblike material which will enter into contact with the tubular winding-up
core
A. In this case also, provision being made for interrupting the delivery of
the
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~u::esi, s hy the spraying nozzles 121, it will be possible to prevent
contamination of the severing member 27 by the adhesive. In practice, the
severing member will act between two linear areas of adhesive, the more
forward one in order to seal the finished roll and the more rearward one in
order to initiate the subsequent winding-up.
The use of two series of nozzles 53 and 121 is expedient when the
adhesives used for sealing the final edge of the roll and anchoring the
initial
edge to the core are of different nature and features. This depends on the
type of product wound up and/or the winding-up speed.
Figs. 2, 3 and 4 show three consecutive phases in the operation of
winding-up a roll of weblike material.
In Fig. 2, the roll R is in an intermediate phase of formation. A new
core A, in this example, has already been positioned for subsequent
insertion. Fig. 3 shows the phase of completion of the winding-up of the roll,
with the separating member which rotates in the direction of the arrow f27
and enters the channel defined between the rolling surface and the upper
winding-up roller 7. The nozzles 121 spray the adhesive necessary for the
sealing of the final edge. Fig. 3 also shows the phase of delivery of the
adhesive to the new core A by the nozzles 53 on the weblike material N
before its severing. This delivery may be simultaneous or staggered in time,
and in particular advanced, by comparison with the delivery by the nozzles
121. Fig. 4 shows the subsequent phase, in which a new core A has already
been inserted into the channel defined between the rolling surface 25 and the
winding-up roller 7, in contact with said rolling surface and with the weblike
material N passed around the winding-up roller 7. Downstream of the
severing member, the weblike material N has been torn to form a final edge
LF which eventually becomes wound up onto the roll R, and to which the
adhesive C has been applied by the spray nozzles 121. LI designates the
initial edge which is wound up onto the new core. The unloading of the roll R
from the winding-up cradle takes place in a manner known per se.
In the example shown, the machine also has a printing unit, generally
designated 131 and comprising an inker 133, a screened cylinder 135 and a
plate cylinder 137 which bears the plate on which is engraved the design,
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decoration, text or other information to be printed on the weblike material.
In
;-wis exampie, only the ply V1 of the weblike material N is caused to pass
onto
the return cylinder 139 with which the plate cylinder 137 interacts, while the
other ply V2 is passed, without printing, to the embossing unit or, possibly,
directly to the ply-bonding unit.
It is understood that the drawing shows only a simplification of the
invention, provided by way of a practical demonstration, and that it may be
varied in shapes and arrangements without thereby departing from the scope
of the concept underlying said invention.
