Note: Descriptions are shown in the official language in which they were submitted.
CA 0221093~ 1997-07-18
METHOD AND DEVICE WITH ACTIVE OSCILLATION DAMPING
FOR WINDING A WEB OF PAPER INTO A ROLL
The present invention relates to an oscillation
suppression oscillator in accordance with the preamble to
Claim 1, and to a device for winding a traveling web of paper
into a roll in accordance with the preamble to Claims 3 and
20.
Winding machines for the winding of paper webs can be
arranged at the end of a paper machine in order to bring the
web of paper~obtained there into the form of a roll (so-
called Pope reel winder). However, they are also used in
order to rewind a finished roll in order to produce rolls of
a very specific quality of winding.
In all cases, the paper roll is to have very specific
properties, in particular with respect to its hardness. The
hardness of the roll should generally decrease from a certain
initial value to a final value, a hard core winding at the
very start being of particular importance. The decrease
should be as uniform as possible from the first layer to the
last layer. It should have a given gradient which is not too
great and not too slight. The variation in the hardness of
the roll should in no case show abrupt changes, for instance
a sudden decrease. No radial or tangential stresses which
impair or damage the web of paper must occur in the roll.
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It has already been attempted to achieve all of this,
but without success. Winding machines of known construction
produce instead of this, for instance, rolls in which the
core is either extremely soft or extremely hard and in which
there is a strong decrease in the hardness of the roll
towards the end -- for instance at four-fifths the diameter
of the roll. This has the result that the first part, and
therefore the extremely soft or hard core, cannot be used
since the web is crushed and bursts in this region, so that
this part must be thrown away as reject; in the region of the
end, in which the roll has not been wound sufficiently hard,
there is a lateral displacement of the layers relative to
each other so that the sides of the finished roll appear
frayed and the edges of the web can be easily damaged.
A poorly constructed core (too little or too great a
hardness) namely does not permit a dependable forming of the
rest of the roll. This problem is particularly serious in
the case of pressure-sensitive papers, for instance self-
duplicating (SD) papers, in the case of which narrow limits
are set for the pressing of the shaft bearing the roll being
produced against the outer surface of the carrier drum.
In the method known from DE 40 07 329, the roll of paper
being produced is shifted in horizontal direction
corresponding to the increase in the size of the roll. The
roll of paper reaches a high weight, which can exceed
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hundreds of tons. For this reason, the roll of paper cannot,
upon its growth, be pressed, in sensitive fashion, against
the pressing drum.
DE 44 15 324 shows and describes a winding machine for
winding a web of paper on a shaft with central drive. This
machine comprises a winding station, a receiving station, and
an idle pressing roller. The pressing roller rests against
the circumference of the secondary roll of paper all the way
up into the winding station. The web is guided in such a
manner that it enters continuously, without wrapping, into
the inlet slot. If such a winding device is operated with
high speeds of the web, preferably more than 1000 meters a
minute, then oscillations of the pressing roller occur
suddenly and unexpectedly, which may lead in case of
resonance to damage to the winding device. In order not to
permit this to occur, the diameter of the pressing roller has
been selected as small as possible, and predominantly of the
same size as that of a normal web guide roller. This has the
disadvantage that the pressing roller, due to the absence of
sufficient flexural rigidity is not adapted to apply linear
forces of any desired value and in particular not to
extremely large web widths (up to about 10 meters).
From USA 5,431,261, a controlled oscillation suppressor
is known. This oscillation suppressor had the disadvantage
that large masses in the region of several tons, such as the
CA 0221093~ 1997-07-18
previously described pressing-drum or pressure-roller device,
could not be damped since as active or excited resonators
there were always used ones which were tuned
magnetostrictively or electrorestrictively to different
frequencies.
The first object of the invention is thus to indicate
resonators which can be used as oscillation suppressors for
oscillations of large masses.
A second object of the invention is to provide a winding
device in which the disadvantages of the prior-art devices
are avoided, and in particular in the case of winding devices
in accordance with the preamble to Claim 1, such as known
from DE 44 15 324, oscillations of the pressing-drum or
pressure-roller device which comprises a pressing-drum or
pressure roller are suppressed.
In accordance with the invention, the first object is
achieved by Claim 1 and the second object by the device
according to Claim 3 and the method according to Claim 20.
Instead of magnetostrictive or electrorestrictive
elements, the invention proposes, in order to obtain the
first object, the use of hydraulic or gas-filled cylinders
the stiffness KA of which is adjusted as a function of the
pressure prevailing in the cylinder, against which pressure
the piston must be moved. It is advantageously provided for
such a device that the predetermined movable mass, i.e. a
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--5--
mass which carries out an oscillating movement, be arranged
between two cylinders and be connected with pistons of the
same rigidity. In addition to the possibility of adjusting
the stiffness KA in such a system by change of pressure, it
is also possible, upon the connection of the two cylinders,
to introduce a damping member via a line containing a choke,
whereby a given frequency spectrum or frequency band can be
associated with the movement of the cylinders.
Essential reasons for the occurrence of oscillations of
the pressing-drum or pressure-roller device which comprise
the pressing drum or pressing rollers, referred to below as
Sensomat rollers, and are part of the sensitive winding
device, are, in accordance with the findings of the
inventors, deviations of the wound paper roll from the ideal
circular contour. As the inventors have found, a paper roll
always has places which are not round, for instance
compression places, which can excite the Sensomat rollers and
the carrier device connected therewith to oscillation. This
is due to the fact that in the case of the winding device in
accordance with Claim 3, the Sensomat roller is not supported
as in other device of the prior art by an infinitely large
mass, for instance a foundation, but is arranged on a device
which is movable relative to the paper roll, so as to move
away from the center of the roll upon the increase in the
diameter of the roll.
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The invention therefore proposes, for the solution of
the second object, in a system having a pressing-drum or
pressure-roller device which is movable relative to the shaft
or paper roll, an oscillation suppressor by which these
oscillations which occur can be suppressed.
As example of such an oscillation suppression device,
the invention proposes providing on the supporting device,
which, for instance, can be developed as a rail and is
fastened on the support of the pressing-drum or pressure-
roller device, a mass which can move on the supporting device
relative to the pressing-drum or pressure-roller device, for
instance in the manner that it slides guided along the path
or rolls on a rail. The movement of the mass is that of a
harmonic oscillator, i.e. upon deflection of the mass from
its position of rest it experiences, in the ideal case, an
opposing force which increases linearly with the deflection,
so that an oscillating movement, and therefore a swinging of
the mass is obtained when the latter is excited to this.
This can take place by self-excitation, for instance
upon occurrence of a swinging of the sensor roll or of the
pressing-drum device or, in a further development of the
invention, by means for exciting the oscillation, one special
embodiment consisting therein that the means for exciting the
oscillation comprises at least one actuator, for instance a
hydraulic cylinder or a cylinder filled with gas, for
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instance air.
In a further embodiment, it can be provided that the
means for exciting the phase-displaced oscillation comprise a
movement sensor which is arranged on the pressing-drum or
pressure-roller device. By the noting of the movement of the
pressing-drum or pressure-roller device the frequency of
oscillation thereof can be determined. In this way it is
possible in a further embodiment to determine the
instantaneous oscillation frequency or oscillation frequency
band of the pressing-drum or pressure-roller device.
These signals can be used, in one particularly
advantageous embodiment, in order to control means for
adjusting the frequency with which the mass of the
oscillation suppressor oscillates. The desired tunability or
variability of the frequency permits an oscillation
suppression oscillator which comprises at least two cylinders
which can be filled with hydraulic fluid or a gas.
In a further development of the invention it is provided
that the oscillation suppressor comprises an open-loop or
closed-loop control device with which, as a function of the
measurement signal produced by the movement sensor, the means
for adjusting the oscillation frequency are so controlled
that the oscillation frequency or frequencies of the mass
always correspond to the oscillation frequency or frequencies
of the pressing-drum device. This can take place, for
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--8
instance, in the manner that the pressures in the
aforementioned cylinders are so adjusted that a given
stiffness of the cylinders is obtained whereby the "spring
constant" of the oscillator consisting of mass and cylinder
is adjusted. This thus permits a change in the oscillation
frequency of the oscillator.
The open-loop control can be expanded to a closed-loop
control even if a movement sensor is provided also on the
mass of the oscillator for the suppression of oscillations,
so that the phase of the oscillations with respect to each
other can be determined from the movement signal of the
pressing-drum device and oscillation-suppression device. The
oscillation excited by the actuator is excited by means of
the closed-loop control in such a manner phase shifted with
respect to the first that a substantially complete
extinguishing of the undesired oscillation of the pressing-
drum or pressure-roller device is effected, even if the
undesired oscillation of the pressing-drum device changes
with time.
In an entirely different concept of the oscillation
suppression, it is provided that the support device not be
firmly connected only with the pressing-drum or pressure-
roller device but that furthermore it has a firm support on,
for instance, the wall or the carrier means for the pressing
drum itself, which is movable relative to the shaft. In a
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first embodiment of this second concept, it is provided that
the oscillation suppressor comprises a hydraulic cylinder,
the hydraulic lines connected to the hydraulic cylinder
having a choke. If the web has an unevenness, then the
piston of the cylinder of the oscillation damping device is
deflected. In this way, for instance, hydraulic fluid is
displaced out of the cylinder. Since the choke prevents an
immediate discharge of the hydraulic oil out of the cylinder
or opposes resistance to it, the stiffness is increased and
thus, depending on the strength of the deflection, due to the
unevenness exerts an opposing force on the Sensomat roller,
with the result that an oscillating thereof is avoided.
In addition to the device, the invention also proposes a
method in accordance with Claim 20 in which the oscillations,
particularly resonant or sympathetic oscillations of the
pressing-drum or pressure-roller device against the roller
bearing the web of goods are suppressed.
In a further development, it is provided that, as
additional method step, the movement of the pressing-drum or
pressure-roller device be noted by a movement sensor and, on
the basis of this movement signal, the oscillation frequency
or the oscillation frequency band of the movement is
determined.
In a further development, it can then be provided that,
as a function of the frequency signal or frequency-band of
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- - 10 -
the movement of the pressing-drum or pressure-roller device
noted, the stiffness of the oscillation suppressor is so
adjusted that the oscillation frequencies of the oscillation
suppression device or the frequency band agrees with that of
the pressing-drum or pressure-roller device. In this way,
the undesired oscillation of the pressing-drum device is
suppressed by opposite-phase oscillating of the excited
oscillator.
In order to be able to adjust the phase of the
compensation oscillation, a further development of the method
is provided for noting the movement of the oscillation
suppression oscillator mass, and for determining the phase
from the movement signals of the pressing-drum or pressure-
roller device and the oscillator mass, the phase and
controlling the oscillator mass accordingly so as to deflect
it shifted in phase.
The invention will be described below by way of example
with reference to the figures.
In the drawing:
Fig. 1 is a schematic showing of an oscillation
suppression device having a predetermined mass;
Fig. 2 is a schematic showing similar to Fig. 1, in which
however movement sensors are arranged on the
compensation mass and the oscillating mass;
Fig. 3 is an alternative embodiment of an oscillation
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suppression device, which is supported in fixed
position;
~ig 4 shows a winding device without oscillation
suppression device;
~ig. 5 is a first embodiment of a winding device having an
oscillation suppression device, the Sensomat roller
being rotatably mounted;
~ig. 6 is a second embodiment of a winding device having
an oscillation suppression device the Sensomat
roller being displaceable substantially axially;
~ig. 7 is-a winding device having an oscillation
suppression device which has a movement sensor to
take up the movement of the pressure roller;
~ig. 8 is a winding device such as that shown in Fig. 7,
which, in addition, has a further sensor to note
the movement of the oscillation suppression
oscillator;
~ig. 9 is an alternative embodiment of an oscillation
suppression device 5 in which the oscillation
suppression device is supported fixed in position
on the device bearing the Sensomat roller;
~ig. 10 is a detailed showing of the oscillation
suppression device of Fig. 9;
~ig. 11 is a second embodiment of an oscillation
suppression device which is supported fixed in
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position.
Fig. 1 shows schematically an embodiment of the
arrangement in accordance with the invention of a winding
device with an oscillation suppression device, the
oscillation suppression device not supporting itself.
As shown in Fig. 1, the system can be described in
simple fashion in the manner that a mass MW is associated
with the wound roll. The pressing-drum device, comprising
the Sensomat roller has a mass MSw. Should it happen for any
reason whatsoever that there is oscillation of the Sensomat
roller or the pressing-drum or pressure-roller device excited
by the wound roll, such oscillation can be described by the
model of one or more harmonic oscillators having one or more
oscillation frequencies or an oscillation frequency band.
"By the model" means that the Sensomat roller has a certain
stiffness KS and a certain damping Cs with respect to the
wound roll. These constants determine the oscillation
frequency of the harmonic oscillator. When the mass of the
wound roll is much greater than the mass of the Sensomat
device, then in a first approximation for the frequency with
which the Sensomat roller oscillates we have ~ = ~K /M
The oscillation frequencies of the pressing-drum device lie
preferably between 10 and 50 Hz. With regard to the
theoretical description of oscillations, see, for instance,
"Dubbel, Taschenbuch fur Maschinenbau, 18th Edition, pages
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B37 - B44, 1996, published by Springer Verlag, Berlin".
As oscillation damper there is provided a predetermined
mass MR which oscillates freely against the mass MSw, this
system, in its turn, having a given stiffness KA and a given
damping CA, for the frequency of which system we again have,
in first approximation, ~0 ~ ~Ko/MR.
If the mass MSw is now excited to oscillation, this
undesired oscillation can be suppressed in the manner that
the predetermined mass MR is excited with the same frequency,
also to an oscillation which, with corresponding phase
displacement, compensates for the oscillation of the mass
MSw, i.e. we have ~s ~ ~o- In order to adjust the frequency
of oscillation there is used essentially the variation of the
stiffness KA of the oscillation suppression oscillator.
Fig. 2 is a showing of the same arrangement as Fig. 1,
but the pressing-drum device with the mass MSw as well as the
predetermined mass of the oscillation suppression device have
movement sensors 1 and 3 respectively which obtain movement
signals of the mass from which the frequency and the phase of
the oscillations with respect to each other can be
determined. By means of the open-loop/closed-loop controller
5 it is then possible to control the oscillator of the
oscillation suppression device with the mass MR in such a
manner that it oscillates both in frequency and in phase
precisely in such a manner as to compensate for the
CA 022l093~ l997-07-l8
-14-
oscillation of the Sensomat roller.
Fig. 3 again shows the system consisting of a mass Mw of
the wound roll and MSw of the pressing-drum device which are
coupled oscillationally with each other, and an oscillation
suppression device, the oscillation suppression device having
a fixed support 7 and the mass of the pressing-drum device or
else of the Sensomat roller alone is elastically supported
thereon. With a knowledge of disturbing influences which
come from the wound roll having the mass Mw, such systems can
be controlled in such a manner that the oscillation
suppression device has a given stiffness KA and a given
damping CA so that blows on the mass of the Sensomat roller
or pressing-drum device are compensated for by an opposing
force so that no excitation to oscillation of the Sensomat
roller or pressing-drum device takes place.
Fig. 4 shows an embodiment of a winding device of the
above type without the oscillation suppression device of the
invention.
The winding device 10 comprises a horizontal carriage 12
which is part of the pressing-drum or pressure-roller device.
The horizontal carriage 12 is movable in horizontal direction
on a guide path 14, as shown. The horizontal carriage 12
bears the pressing-drum or pressure-roller 16. The pressing
drum 16 can have a drive. The supports 18 of the pressing
drum 16 ("Sensomat roller") are also movable horizontally by
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-15-
means of a short-stroke force producer 20 ("Sensomat~) on the
horizontal carriage 12. The horizontal carriage 12
furthermore bears a scraper 22 for conducting the web of
paper downward (as waste).
Spaced horizontally from the horizontal carriage 12
there is a device 24 for the support of the paper roll 26
being produced (support device). The support device is
merely indicated schematically here. It may have different
embodiments. Thus, it can, for instance, comprise two
rollers which are parallel to the roll of paper and around
which a support belt is wrapped.
A pressure roller 26 is provided in the region of the
support device 24. It extends over the entire width of the
paper roll 26.
As shown in Fig. 4, the paper roll 28, has deviations,
shown exaggerated in size, in the contour of its surface at
the point 30 from the ideal circular course expected. Since
this unevenness continues or increases during the entire
winding process, it will come into contact at periodic
intervals with the Sensomat roller 16 and in this way, via
said Sensomat roller, excite the entire pressing-drum device
to undesired oscillations. This is due to the fact that a
closed-loop controller readjusts the short-stroke cylinder in
order to maintain a given linear force in the direction of
the place of indentation. The Sensomat roller 16 can, as a
CA 0221093~ 1997-07-18
result of this control, start to oscillate and transmit this
oscillation to the movably supported horizontal carriage 12
and thus lead to an oscillation of the entire pressing-drum
device. It is to be noted that the short-stroke cylinder 20
is merely one example of pressing means by which the
pressing-drum or pressure-roller device can be brought into
contact with the shaft in order to apply the desired linear
force to the shaft or wound roll.
The position of the winding device shown in Fig. 4
characterizes an operating phase of the winding device in
which the paper roll 9 is practically completely wound. The
horizontal carriage 12 is in its extreme left-hand position.
By the horizontal mobility of the pressing carriage 12, the
latter travels, with simultaneous maintaining of the contact
of Sensomat roller and wound roll with increasing diameter of
the roll, towards the left in the embodiment shown.
As stated, the pressing drum 16 lies against the
periphery of the paper roll 26 while the pressing roller 28
is still not in contact with the paper roll. Contact takes
place only when a change in roll, which will not be described
in this application, is to be effected.
Fig. 5 shows a second possible embodiment of a device in
accordance with Fig. 4, which already comprises an
oscillation suppression device. In principle, the winding
device shown in Fig. 5 differs from that shown in Fig. 4 by
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-17-
the fact that the mobility of the pressing drum 16 ("Sensomat
roller") is not produced via a horizontally movable carriage
but by suspension of the Sensomat roller on a sort of a
mathematical pendulum 40 which can be fastened, for instance,
to a cover 42 and is rigidly connected via the connection 44
to another pendulum 46 which bears the pressing device in the
form of a short-stroke cylinder 20. On the support 18 of the
pressing drum 16 there is firmly attached a support device 50
which bears a guide path 52 on which a predetermined mass MR
54 is horizontally movable. The compensation mass 54 which
is movable independently in horizontal direction on the guide
rail 52 is connected with the piston rods 56, 58 of two
cylinders 60, 62 which can be filled with gas or a liquid and
are firmly anchored on the guide path. If the Sensomat
roller or pressing device is completely at rest, then the
compensation mass is also at rest, namely in its equilibrium
position, preferably in a central position between the two
cylinders. The manner of operation of the cylinders will be
explained in further detail in connection with the
embodiment, shown in Fig. 5, of the winding device with
horizontally displaceably pressing-drum or pressure-roller
device, which also has an oscillation suppression device such
as shown in Fig. 5.
As already described in Fig. 5, upon oscillations of the
Sensomat roller 16 which may lead to an oscillation of the
CA 022l093~ l997-07-l8
- -18-
entire pressing-drum device, the mass MR 54 of the
oscillation suppression device 70 which rests, via the
support device 50, exclusively on the support 18 of the
Sensomat roller 16, excites an oscillation which compensates
for the oscillation of the Sensomat roller or pressing-drum
device. In this connection, it is to be noted here that the
frequency of oscillation of the pressing-drum device,
comprising the Sensomat roller and the horizontal carriage
since the short-stroke piston 20 attempts to hold the
Sensomat roller in a given position on the horizontal
carriage, corresponds to the frequency with which the mass MR
oscillates. For this, it is necessary to be able to adjust
the frequency of oscillation of the compensation oscillator
consisting of the mass MR and the piston 60, 62. This is
done in the manner that the pressure prevailing in the
cylinders 60, 62 which are filled with hydraulic fluid or
with gas, against which the pressure of the pistons must work
upon displacement is varied. It has namely been found that,
for adiabatic guidance and filling with an ideal gas, the
opposing force which the pistons build up upon displacement
amounts in first approximation to:
F - f(Pz) . x,
in which x is the displacement of the piston rod in
horizontal direction. However, this means that for the
stiffness we have:
CA 0221093~ 1997-07-18
-19-
KA = f(Pz)~
and therefore the stiffness is a function of the gas pressure
Pz prevailing in the cylinder.
Fig. 7 shows an embodiment of the winding device with
oscillation suppression devlce 70 according to Fig. 6, in
which the oscillation suppression device furthermore
comprises a movement sensor 80 which notes the movement of
the pressing-drum or pressure-roller device and feeds the
movement signal to a control unit which determines the
frequency of the movement of the pressing-drum or pressure-
roller device from the movement value. The control device 82
then changes the stiffness of the oscillation suppression
oscillator having the predetermined mass MR 54 in such a
manner that the frequency with which this system oscillates
or is excited agrees with the frequency with which the
pressing-drum or pressure-roller device oscillates. Since
the stiffness in the case of a cylinder filled with an ideal
gas with the pre-established surrounding parameters is a
function of the pressure Pz in the cylinder, it is for
instance possible, based on a table drawn up in accordance
with calibration measurements in which the pressure values of
the cylinders 60 and 62 are associated with the stiffnesses
of the oscillation suppression oscillator system to adjust KA
as desired. Therefore, in accordance with the desired
frequency or stiffness, the cylinders 60 and 62 are acted on
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-20-
by a corresponding pressure Pz over the lines 84.
In Fig. 8, the oscillation suppression device of Fig. 7
is further developed in the manner that, in addition, there
are also introduced into the system movement sensors 90, 92
which note the movement of the oscillation suppression
oscillator and feed these movement signals to the control
unit 82 which in the present case can operate also as closed-
loop control unit. By the obtaining of this signal it is
namely possible also to adapt the phase of the oscillations
to each other, which makes a targeted actuation of the
oscillation suppression oscillator possible so that an active
oscillation suppression can be carried out. For this,
special control programs are required, such as known from US
patent US-A 5,431,261, the disclosure of which is included in
its entirety in the present application. US-A 5,431,261
relates to an active control process for damping oscillations
of a large mass by means of a oscillation suppression
oscillator. In essence, a variable force is exerted on the
oscillation suppression device, which force is proportional
to the displacement of the oscillation suppression mass and
has a given time delay controlled by open-loop or closed-loop
control. With such a control algorithm, oscillations can be
actively suppressed by regulating the oscillation suppression
oscillator.
CA 0221093~ 1997-07-18
In Fig. 9, an entirely different concept of a
oscillation suppression on a winding device is shown.
Advantageously, in this connection no additional support
device 50 as compared with the embodiments of Figs. 5 to 8 is
required since the oscillation suppression system is not
fastened exclusively on the bearing 18 of the Sensomat roller
16 but to it and to another support which is stationary. For
example, the short-stroke cylinder can, by suitable
conversion, itself be used to dampen oscillations of the
Sensomat roller. This is possible by the converting of the
short-stroke-cylinder, as shown in detail in Fig. 10.
The short-stroke cylinder 20 has two chambers 100 and
102 which are separated by a piston 104 which is seated on a
piston rod 106, which, in its turn, is connected with the
bearing 18 of the Sensomat roller 16. In the two chamber
pressures P1 and P2 prevail, P1 being all cases greater than
P2. In the feed line 108 to the chamber 100 and the feed
line 110 to the chamber 102 there are present chokes 112 and
114 respectively. Should there now be present an ovalness or
unevenness 30 in the wound roll 26, then the Sensomat roller
receives a push, for instance towards the left. Due to the
reduced cross section, the hydraulic liquid or the gas in the
chamber 100 cannot escape rapidly enough, so that there is a
rise in pressure which builds up an opposing force which is
substantially linear to the displacement, so that the push of
CA 0221093~ 1997-07-18
the Sensomat roller is acted on, with this arrangement, by an
opposing force and thereby compensated for. An exciting of
the system is no longer possible in this way. Nevertheless,
at all times the same average constant linear force is
introduced into the slot 116 between Sensomat 16 and roll 30.
In Fig. 9, as in all other figures, the guidance of the web
of paper 120 around the Sensomat roller 16 and onto the wound
roll 26 is also clearly shown.
The embodiment in accordance with Fig. 11 shows an
alternative embodiment of the oscillation suppression device
of the invention which is shown in Figs. 9 and 10. In
contradistinction to the embodiment in accordance with Figs.
9 and 10, in this case an additional cylinder 130 is used for
the compensation, which cylinder can be supported for
instance in a bracket 134 on a wall 132. The web of paper
120 is passed through the opening 136 in the wall 132. The
somewhat greater structural expense of Fig. 11 makes it
possible, however, contrary to the embodiment of Figs. 9 and
10, to provide two separate controls for the short-stroke
cylinder 20 and the oscillation suppression cylinder 130.
While the controls of the short-stroke cylinder 20 on the
average see to it that the linear force in the slot 116
between the wound roll 26 and the Sensomat roller 16 is
retained, any unevennesses which occur in the surface of the
roll are done away with by corresponding opposing forces with
CA 022l093~ l997-07-l8
-23-
the help of the oscillation suppression cylinder 130 against
these unevennesses.
In this way, not only is an oscillation of the pressing-
drum or pressure-roller device, which also comprises the
horizontal carriage, compensated for, but, in addition, with
corresponding application of an opposing force, the wound
roll is also smoothed so that, in contrast with the previous
devices, the unevenness does not increase but is compensated
for on the average and the desired round contour of the
package is thus obtained.
The control of the oscillation suppression cylinder ls
controlled as a function of the contour of the roll. For
this, it is necessary to measure the contour of the package
over time. This can be effected, for instance, by means of
an optical or a mechanical sensor which measures deviations
from the ideal round contour or else by variation of the
force on the piston 130 averaged over several cycles and
placed in a memory unit (not shown) so that a self-adaptive
adaptation of the compensating forces to the contour of the
roll is possible.
By the oscillation suppression device of the invention
it is thus possible, for the first time, to suppress
undesired oscillations of the pressing-drum or pressure-
roller device in a winding device in which the wound roll
itself is substantially fixed in space and the pressing-drum
CA 02210935 1997-07-18
or pressure-roller device is displaced relative to the roll
as it increases in size, in whlch connection a constant
pressing force in the slot between Sensomat roller and roll
on the average is seen to by means of a pressing device which
can be designed as a short-stroke cylinder.
