Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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sBACKGROUND OF THE INVENTION
s~It is well-known in the art how to prepare long rolls
(sometime called "logs") of paper on rewinding machines for
the production of toilet paper, kitchen towels or the like.
The rolls are made from webs of paper (which may be as wide
as 5 meters) and are unwound from a large "parent roll" onto
a cardboard core. These 5 meter long "logs" generally have an
external diameter of 4 to 5 inches, and in many cases may
also be slit into smaller rolls approximately 4-1/2 inches
wide. The webs may also be transversely perforated to provide
` ~individual sheets 4-1/2 x 4-1/2 inches square.
It is important, for economy of operation and costs,
carefully to control the amount of paper wound onto the
cores, the number of sheets or usable units provided in the
roll, and the outside diameter of the roll. Furthermore,
because the rewindinq machines operate at very fast speeds it
is also important to ensure that the leading edge of the web
is secured to the core and that the separation of the "tail"
of one roll be precisely and rapidly separated from the
leading edge of the following roll.
~Relevant patents relating to the background of this type
iof paper-converting machinery and process are the U.S.
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iPatents 3,869,095, 4,327,887 and 4,422,588. `~
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DESCRIPTION OF THE INVENTION
The invention is an improvement on prior means for the
formation of rolls ox logs by winding a web of paper or
similar material on a core. Prior art shows a first rotary
winding roller along which the web material is driven: a
second rotary winding roller forming a nip with said first
winding roller to receive a fed core: means for inserting a
core into said nip; and a movable roller to control the
diameter of the roll or log during formation between said
three rollers. The prior apparatus also provides for
cyclically varying the surface speed of the second winding
roller and of the diameter control roller in order to
achieve, during each insertion of a new core, the slackening
of the web and thus the wedging of a double thickness of web
between the just-inserted core and the second winding roller.
This may include pneumatic means. This causes the paper to
start the winding on the newly- inserted core and to tear
between the just-finished roll and the newly-inserted core.
The present invention simplifies the apparatus and makes
the start of the winding of paper on the core more regular.
Thus there is provided that only the second roller be
combined with means for reducing the speed thereof during the
phase of inserting a core into said nip; that means be
provided to wet with glue the cores to be inserted in said
nip; and that a take-off surface extends from a zone of said
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~ second winding roller which is adjacent to the exit of said
,~ nip .
With the above and other objects in view, more
information and a better understanding of the present
invention may be achieved by reference to the following -
detailed description.
DETAILED DESCRIPTION ;
For the purpose of illustrating the invention, there is ~
shown in the accompanying drawings a form thereof whlch is at ~ -
present preferred, although it is to be understood that the
several instrumentalities of which the invention consists can
be variously arranged and organized and that the invention is
not limited to the precise arrangements and organizations of
the instrumentalities as herein shown and described. ~
; In the drawings, wherein like reference characters ~-
indicate like parts~
Fig. 1 shows a schematic cross-sectional side view of an
embodiment of the apparatus during an intermedlate operative
step of the formation of a roll, showing also an assembly for
the feeding of the cores.
Figs. 2 and 3 show the start of a phase for the
separation of the web to remove the formed roll and the
starting phase of the formation of a new roll. ~;~
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Fig. 4 shows in detail a device for supporting and
moving a takeoff surface.
Fig. 5 shows a modified embodiment of Fig. 4.
Referring now to Figs. 1 to 3, numeral 1 indicates a
first upper winding roller, around which there is
continuously driven the web N~ which is transversally
perforated at predetermined distances according to the size
of the sheets that must be detached from the finished roll.
Numeral 3 indicates a second, lower winding roller
which, together with roller 1, defines space (i.e., a nip 5)
for the insertion of a tubular core made of cardboard or
similar material, around which the roll is to be formed.
Numeral 7 indicates a diameter control movable roller
which cooperates with rollers 1 and 3 to form a roll R of
paper material N which is fed without stopping. Numeral 9
indicates a take-off surface which is a part of a unit 10
that may be either fixed or adjusted in position. The
surface 9 has a front edge 9a, substantially adjacent and
almost touching the lower winding roller 3 at the zone of
formation of the roll R between the three rollers 1, 3 and 7.
The surface 9 may be slightly inclined to allow the
spontaneous rolling removal of the roll in the direction of
arrow f9.
Numeral 12 generally indicates a pusher for the
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`insertion of a core Al into the nip 5 formed by rollers 1 and ~
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3. The pusher 12 may be formed by arms pivoted at 14 to the
fixed structure and having an end 12a to push the core A1
into the nip 5.
Numeral 16 indicates an assembly for successively
feeding cores to the position A1, from which they are moved -
by the pusher 12 to the nip 5. 1-~
This assembly 16 may comprise a flexible conveyor 18 -~
having a plurality of seats for the cores A fed from a chute-
like supply resarvoir AO. Along the path of the conveyor 18, j ~
the cores have adhesive applied thereto by a distributor 20 - -
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which may comprise a basin 22 and an assembly of distribution -~
cylinders and counter-rollers, generally indicated by 24, to ;~ ~-
transfer a required amount of adhesive onto their surface
until they contact a core in transit, thereby determining a
glueing region on said core. The glueing region may consist
of either longitudinal segments parallel to the core axis or ;
annular bands of adhesive spaced from each other. The `~
~- adhesive is such as to ensure the anchorage of the leading
edge of the web material N that must be wound on the core. !: ~ .
The winding roller l rotates with a peripheral speed
corresponding to the feeding speed of the paper web N and,
therefore, with constant speed. According to the invention,
the diameter control roller 7 also rotates uniformly at the ~;
same circumferential speed of roller 1. However, the winding
j roller 3~rotates at the same peripheral speed as rollers 1 and
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7, for the most part of the windlng cycle.
However, during the replacement of the ~ormed roll R with
a new core A1, roller 3 undergoes a short slowing down phase
for the purposes indicated below.
When a roll R has reached the required diameter, or when
it has accumulated a desired length of paper material, or
when it has reached such a length of material as to include a
predetermined number of sheets, the pusher 12 moves the core
A1 in the direction of arrow f12 into the nip 5 where it
comes in contact with rollers 1 and 3.
At the same time, the winding roller 3 is made to slow
down slightly which causes the roll R to move in the
direction of arrow f9 until it strikes the front edge 9a of
surface 9. The slowing down of roller 3 also causes a slight
advancement of core Al into the nip 5.
When the roll R contacts the leading edge of surface 9,
it is instantly and abruptly slown down, and this causes a
slackening of the web stretch NO ~see Fig. 2) between its
point of contact of core Al with the roller 1 and its point
of contact with roll R. Therefore, the paper material (that
comes in contact with the core Al having adhesive thereon)
tends to adhere to the core Al. During rotation of the core
between rollers 1 and 3, the core drags the web material
around itself towards the contact region between itself and
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the roller 3. At the same time, the slackening of the
portion NO (which forms a loop) provides an easy folding and
wedging of the web material between the core Al and the
roller 3. A reversing of the paper ~material is thus caused
in a direction opposite to that of the advancement of said
material during the winding thereof on the roll R. As a
result, the web N is torn in the region NO. If the web is
perforated (for the formation of a log or roll made up of a
plurality of sheets to be detached along the perforation
lines), the web tears along the perforation in region NO. It
is preferred that the web in region NO is determined by a
synchroniæation between the core assembly 16 and the lines of
transversal perforations formed in the paper material N.
With the tearing of web N at the region NO, the roll R
is separated from the incoming web material N and is moved
away in the direction of arrow f9 by the rolling effect
:~ caused by the rotation of the diameter control roller 7, and
made easier by the inclined surface ~. The leading edge of
web N is glued to the core Al and pressed thereon by the
contact of the core between roller 1 and with roller 3 so
that, during the rotation of the core, the web end fold,
which has wedged itself between the core 1 and the roller 3,
is made to follow the rotating core. In this way the winding
of the paper material begins immediately on the
~ newly-inserted core Al.
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The completed roll R is moved away (see Fig. 3) and the
diameter control roller 7 is lowered towards the nip 5 to
come in contact with the new roll that has just begun to be
formed. The new roll moves out of the nip 5 to come in
contact with the diameter control roller 7 owing to the
difference in peripheral speed between roller 1 and roller 3.
As soon as a core Al has been inserted into the nip 5,
the pusher 12 goes back in a direction opposite to arrow f12
to allow the next core to move to position A1 (Fig. 1) from
the supply assembly 16. This assembly may advance with
intermittent motion or continuous motion. The cycle is then
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repeated in the manner described for the preceding roll.
Fig. 4 shows in detail another embodiment of the
assembly of members already described for the winding and ;~
removing of the formed roll. The surface 9, and in
particular its front edge 9a, facing the nip 5, is advanced
towards the nip the moment the formed roll must be stopped by
I contact with surface 9 and, in particular, with the edge
thereof, in order to cause a sudden stop of the roll and the ;
formation of the loop between the roll and the new core
inserted into nip 5. To this end, the surface 9 is part of a
unit 30 which is moved forward by a rocker arm 32 pivoted at
34 to the fixed housing frame and connected to the unit 30
through a connecting rod 36. The rocker arm 32 is
mechanically connected to a tappet 38 which cooperates with a
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cam 40 mounted on a programming cam ~haft 42. Depending on
the profile of cam 40, the system 38, 32, 36 causes a timely
and temporary advancement of the edge 99a in the direction of
arrow f9 against the just completed roll. This abruptly
breaks the roll and causes the formation of the loop as
described above.
The mechanical connection between the rocker arm 32 and
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the tappet 38 may be of direct type; that is, the two
mechanical members may be rigidly connected to one another.
However, in order to make it possible to vary the phase
between the motion of tappet 38 and the motion of surface 9,
it is particularly advantageous to provide that the angle
between the tappet 38 and the rocker arm 32 may be varied and
`!, pre-set to meet peculiar working requirements, even during
the machine operation. To this end, it may be provided that
the tappet 38 be rigidly connected to a reducer 50
oscillating about the axis 34. The rocker arm 32 may b
r~ connected to one of two shafts (for example, to the slow
shaft of reducer 50), while the other shaft of the reducer 50
is provided with a hand-wheel 52 whose adjustment causes a
$1 change of the angle formed by the rocker 32 and tappet 38.
~`~ Fig. 5 shows schematically an assembly similar to ~the
one of Fig. 4, but in which a different device is provided to
modify the position of the surface 9. In Fig. 5, the rigid
rocker arm 32 is replaced by a rocker arm made up of two
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portions 132A and 132B, the portion 132A being fastened to
the connecting rod 36 and the portion 132B carrying the
tappet 38. The two portions are articulated on the axis 34,
and the portion 132A includes an arm 132C which forms an
acute angle with the portion 132B. This angle may be
adjusted by a screw tension rod 134 having opposite
threadings which engage lnto two movable bushes of portion
132B and of arm 132C. The tension rod 134 can be turned by
the knob 134A in order to change the above-mentioned angle
and thus to change, with respect to tappet 38, the position
of the surface 9.
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It is evident that, by the above described arrangement, :~ -
a winding system is provided for a rewinder or equivalent
paper converting machine, which is simpler than the existing :~
arrangements and which allows a more uniform product to be
obtained. In particular, it affords an easier start of paper
winding on the core, without the presence of unusable pieces
of paper (which occur frequently in the packages obtained
with prior-art rewinders).
It is to be understood that the present invention may be
embodied in other specific forms without departing from the ~:;
spirit or special attributes hereof, and it is therefore
desired that the present embodiments be considared in all
respects as illustrative, and therefore not restrictive,
reference being made to the appended Claims rather than to
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the foregoing description to indicate the scope of the
invention. :
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