Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND APPARATUS FOR WINDING UP METAL STRIPS
ONTO A WINDING MANDREL
The invention relates to a method of and an apparatus for
winding metal strips on a mandrel in a coiler to which the metal
strip is supplied by a feeder comprising a lower and an upper feed
roller, a guide plate being provided under the metal strip for
guidance and a pivotal strip diverter and a pivotal upper guide
plate following this diverter almost up to the mandrel being
provided above the metal strip.
A feeder known from DE 195 20 709 [US 5,961,022]
comprises a fixed-axis lower roller and an upper roller that can be
moved relative to it. The adjustable upper roller is supported in
a pivot frame that can be adjusted by hydraulic or pneumatic
cylinders and that is formed by two spaced rocker arms connected at
a common pivot axis by a base supported on both sides in the feeder
frame. This upper roller can be pivoted by individually actuatable
fluid-powered cylinders, the base connecting the rocker arms being
formed by a torsion spring.
Different pivot angles of the rocker arms and therewith
of the adjustable upper roller can be achieved here by introducing
different adjustment forces at a relatively low different force of
the fluid-powered cylinders because the tension exerted by the
feeder on the strip can be influenced by pivoting the upper roller
and tension can be distributed in this manner.
DE 197 04 447 [US 6,070,472] teaches a measuring roller
for measuring the evenness of a roll strip under tension in a hot-
strip roll train. One or more of these measuring rollers is
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pressed from below against the roll strip and positioned between
the roll frames of the finishing train and/or in the roll direction
downstream of the last roll frame of the finishing train and/or
upstream of a drive apparatus for a reel and/or between the drive
apparatus and the reel. In a measuring roller between the drive
apparatus and the reel the measured value obtained can be used to
pivot the drive apparatus and the strip travel can be controlled
during winding onto the reel mandrel in this manner.
DE 199 53 524 [US 6,470,722] describes a looper that can
measure the radial variation in thickness present on account of the
longitudinal tension prevailing in a metal strip over the strip
width. The looper comprises to this end a looper roll supported at
each end on a respective pivot arm. The pivot arms are subdivided
at a hinge into a shaft arm part and a roller arm part and are
connected to a looper shaft. The hinge transmits a return force
exerted by the metal strip on the looper roller adjusted from below
against the metal strip onto force sensors on the pivot arms. The
return force corresponds to the longitudinal tension so that it can
be determined from the measured return forces. In order to prevent
the roller arm part from lifting off the force sensor, the shaft
arm and the roller arm are connected to one another by a retaining
element. The upstream and downstream travel directions that are
determined for example by the roll frames or feeders, can be
readjusted, as well as the speed or the roller positions can be
adjusted either on the basis of the total longitudinal tension or
of the determined vectors.
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The basic object of the invention is to develop a method
and an apparatus of the above-described type in such a manner that
an improved measuring of the tension of the metal strip in the
coiler can be achieved for controlling the driving apparatus or
feeder to so influence strip travel that a square-end coil can be
formed.
This object is attained in accordance with the invention
with a method in that a strip-tension measurer engages downward
into the coiler from above with the metal strip, determines the
longitudinal tension exerted by the feeder on the metal strip, and
feeds an output corresponding thereto to a feeder controller. As a
result of the engagement of the strip-tension measurer from above
with the metal strip, in particular an optimal contact angle can be
maintained even on the strip end. This would not be possible if
the strip-tension measurer were engaged from below, since in this
case the contact angle is severely limited by the strip guide
including the guide plate required above the metal strip and
becomes so small that no reliable measurement is possible on the
strip end. However, the measuring on the strip end is important
because strip guidance is particularly difficult here on account of
there being no tension exerted on the strip by the finishing frame
of the rolling train.
The invention proposes that the variation in thickness
caused by the longitudinal tension in the metal strip over the
strip width and determined by the strip tension measuring apparatus
engaging downward at a contact angle with the metal strip is
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determined by how much the measured support forces deflect the
suspension support of the strip-tension measurer.
To this end, according to a preferred embodiment of the
invention, for the direct or indirect measurement of support force
the contact angle between the strip-tension measurer engaging
downward with the metal strip is used. The contact angle transfers
force from the metal strip to the roller and from the latter to the
force sensor integrated in the strip-tension measurer.
In order to actuate the strip-tension measurer at least
one cylinder is required, according to the invention a controlled-
stroke pivot cylinder braced against a downstream pivot arm.
Alternatively, there can be two pivot cylinders. Another
possibility for actuating the strip-tension measurer is to provide
the strip-tension measurer in a U-shaped frame engaged by a
cylinder at a symmetry axis of the frame.
It is recommended here that the contact angle be held
approximately constant by controlling the amount of engagement of
the roller. The contact angle is a function of the stroke of the
pivot cylinder or cylinders and the diameter of the wound coil. In
order to maintain an optimal winding during the entire winding
method the stroke of the at least one pivot cylinder can be
monitored. The theoretical value can be calculated during the
winding method independently of the instantaneous coil diameter,
the optimal winding and the position data. In order to detect the
stroke, a path sensor can be built into the pivot cylinder in or on
the cylinder; optionally, the strip-tension measurer, which can be
pivoted in, can be provided with an angle sensor, so that the
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stroke of the pivot cylinder can be calculated. The instantaneous
diameter of the coil can be calculated by a rotation counter of the
mandrel and a strip-thickness sensor. Alternatively, the coil
diameter can also be directly measured, e.g. by an optical laser
sensor.
According to a further advantageous embodiment of the
invention the roller of the strip-tension measurer is rotated up to
the speed of the metal strip prior to engagement therewith. Since
the roller is pivoted during the winding method into the strip,
this speed synchronization can avoid damage to the metal strip by a
subsequent acceleration that otherwise might occur. The roller
drive can take place mechanically and/or electrically and/or
hydraulically.
An apparatus for solving the problem constituting the
object of the invention, in particular for carrying out the method,
is characterized according to the invention in that the strip guide
is designed as a strip-tension measurer that can be pivoted from
above into the metal strip and that is provided with a guide body
that comprises a rotatably supported roller arm that carries a
roller on its front end, and that a force sensor is provided
between the guide body and the roller arm, which sensor is
connected by output technology to a controller of the feeder. The
strip-tension measurer in accordance with the invention thus
fulfills the classic strip guide function at the same time. Namely,
the entire strip-tension measurer pivots counterclockwise from the
out-of-operation position, that is, the raised out-of-use position,
downward into the operating position, engaging downward with the
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metal strip that is running in and guides the metal strip to the
following mandrel with an activated measuring at the same time.
The function of the strip-tension measurer as simultaneous
strip guide is preferably supported by the fact that at least one
front section of the guide plate following the lower roller of the
feeder under the metal strip is designed as a pivotal flap. This
flap can pivot counterclockwise about the axis of the lower feed
roller.
According to an advantageous embodiment of the invention
the guide body connects a rear pivot arm to a front pivot arm of
the strip-tension measurer. In the case of only one pivot cylinder
that would be attached in the rear and thus on the drive side, the
guide body receives, as connection between the pivot arm on the
drive side to the pivot arm on the operator side, the torsion load
is that would be produced by a one-sided actuation of the strip-
tension measurer by only one rear- or drive-side pivot cylinder.
If a driven guide roller is advantageously arranged in the
axis of rotation of the strip-tension measurer that is at a spacing
from the roller arm receiving the driven roller, the metal strip can
be protected from damage when it is guided on the path from the
lower feed roller to the next roller of the following coiler.
A variant of the invention provides that the strip-
tension measurer is arranged with the roller arm facing the mandrel
integrated into the upper guide plate. A combination of strip-
tension measurer and upper guide plate is present in this
arrangement. The front roller of the strip-tension measurer would
follow a upper guide plate extending up to the first pressure
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roller of the mandrel and the free space toward the upper roller
of the feeder would be filled out with a conventional guide.
In one aspect, the present invention resides in a method
of winding metal strip on a mandrel of a coiler, said method
comprising conveying the metal strip to the coiler by a feeder
having a lower feed roller and an upper feed roller, the coiler
comprising a lower guide plate positioned under the metal
strip, a pivotal strip-tension measurer and a pivotal upper
guide plate positioned downstream of the pivotal strip-tension
measurer and extending between a first position spaced above the
metal strip and a second position generally adjacent to the
mandrel; inwardly pivoting the strip-tension measurer into
engagement with the metal strip; determining a longitudinal
tension exerted by the feeder on the metal strip; and
outputting the determined longitudinal tension to a feeder
controller.
In another aspect, the present invention resides in an
apparatus for winding metal strips on a mandrel arranged in a
coiler to which the metal strip is supplied by a feeder
comprising a lower and an upper feed roller, in which a guide
plate is provided under the metal strip for guidance and a
pivotal strip guide and a pivotal upper guide plate extend
downstream from this guide almost up to the mandrel above the
metal strip, characterized in that the pivotal strip guide is
designed as a strip-tension measurer that can be pivoted from
above down into engagement with the metal strip and that is
provided with a guide body that has a pivotal roller arm that
carries a roller on its outer end, and that a force sensor is
arranged between the guide body and the roller arm and sends an
output to a controller of the feeder.
Further features and details of the invention result from
the claims and the following description of an illustrated
embodiment of the invention presented in the drawings.
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FIG. 1 shows a schematic side view of a prior-art coiler;
FIG. 2 shows a schematic side view of a coiler with a
strip-tension measurer that can pivot from above into the
metal strip, simultaneously acts as a strip guide, and when
not in use is lifted off the metal strip;
FIG. 3 shows the subject matter of FIG. 2 with the strip-
tension measurer pivoted into the measuring and use position
shortly before the end of a winding operation; and
FIG. 4 is a cross section through a detail of a guide
roller mounted in the strip-tension measurer.
A prior-art coiler 1 as shown in FIG. 1 is downstream of
the rolling train or finishing frame and winds up the rolled
metal strip 2 on a mandrel 3 to a package or coil 4 (see FIG.
3). The metal strip 2 is supplied to the mandrel 3 by a drive
apparatus or feeder of which only the upper and lower feed
rollers 5 and 6 are shown here. A lower guide plate 7 travels
from the lower feed roller 6 to the mandrel 3. The leading end
of the metal strip 2 fed in this manner first engages a first
pinch roller 8 associated with the mandrel 3 and is followed
by more such rollers distributed over the mandrel's
circumference.
A strip guide 9 that contacts the upper feed roller 5 in
the out-of-use position for receiving the strip is located above
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the metal strip 2. The strip guide 9 is pivoted by a cylinder 10
that has a piston rod connected to a pivot arm of strip guide 9.
The coiler 1 is closed at the top by a upper guide plate 11
traveling from strip guide 9 to the mandrel 3. A cylinder 12 is
articulated to upper guide plate 11 for pivoting it.
In the embodiment of the coiler 1 shown in FIGS. 2 and 3
parts the same as those of the above-described coiler are
identified by the same reference numbers. A significant difference
here is a strip-tension measurer 13 that also acts as the strip
guide. It consists of rear drive-side and front pivot arms 14 of
which only the rear drive-side pivot arm can be seen in FIG. 2.
The two pivot arms 14 are connected to one another by a torque-
transmitting guide body 15 (see FIG. 4). Moreover, it comprises a
roller arm 16 at whose outer end a driven roller 17 is rotatably
supported. The roller arm 16 is can oscillate about a pivot 18.
In order to not swing down because of gravity, the roller arm 16 is
held in position by a retaining element 19.
As soon as the strip-tension measurer 13 pivots from
above down against the metal strip 2 and engages down into it with
its roller 17 while forming a contact angle, a force is applied to
the roller 17 that is applied to the roller arm 16 in a clockwise
direction. However, clockwise rotation of the roller arm is
prevented by a force sensor 20 that also braces the roller arm 16,
determines a force produced at the axis 21 of the support, and
transmits it as a measurement output to a controller 22 (see FIG.
3). The latter can be controlled in such a manner dependent on the
measurement, e.g., by pivoting the upper and/or lower feed
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roller(s) 5 and 6 or by a parallel pivoting of both rollers or by
applying different forces on the drive side and operator side so
that a straight-edged coil 4 can be produced on the mandrel 3.
The strip-tension measurer 13 is provided on its
downstream (in the direction of the strip travel) end at a spacing
from the roller 17 with a guide roller 23 provided in its axis of
rotation, as shown in FIG. 2 and 3 as cross section in the area of
pivot arm 7 through the pin of guide roller 23. Here too the
coiler 1 is closed at the top by an upper guide plate 11 that can
io be pivoted by a cylinder 12. The guide plate 7 that extends
underneath the metal strip 2 from the lower feed roller 6 to the
mandrel 3 and conducts the metal strip 2 is provided at least on
its upstream end with a flap 24 that can pivot counterclockwise
about the axis of lower feed roller 6.
FIG. 3, which shows the shortly before the end of an
operation winding the metal strip 2 to a finished coil 4, can be
accurately determined on the one hand from the contact angle that
the metal strip 2 forms where it engages the roller 17 of the
strip-tension measurer 13. On the other hand, different
measurement outputs 25 and control outputs 26 are indicated by
dotted lines that are fed to the controller 22 or are outputted
from it to pivot actuators of the upper and lower feed rollers 5
and 6 (see dotted lines 26). The parameters essential for
determining and, if necessary, maintaining constant an optimal
contact angle during the entire winding method are set, for
example, by determining the stroke of the pivot cylinder or
cylinders 10 of the strip-tension measurer 13, which cylinder(s)
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is/are provided by a movement sensor, by an angular-position sensor
of the strip-tension measurer 13, or from the instantaneous
diameter of coil 4. This diameter can be determined by sensors
counting revolutions of the mandrel 3 (see dotted line 25 starting
from it) and detecting the strip thickness. Direct measuring of
the diameter of coil 4 is possible, as by the illustrated optical
laser sensor 27.
In any case, it is possible to make a measurement output
available from the strip tension measurer in the coiler for a
feeder controller. This can take place alternatively to the
embodiment shown in the combination the strip-tension measurer with
the strip guide and also by a combination of the strip-tension
measurer with the upper guide plate. The strip-tension measurer 13
shown in FIG. 2 and 3 would then be integrated in the upper guide
plate 11 with its roller 17 facing the mandrel 3, i.e.
symmetrically to both sides of line A-A in FIG. 2. The space that
is then free from upper feed roller 5 to the strip-tension measurer
13 could be filled out or bridged over in this option by a
conventional strip guide 9 (see FIG. 1).
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List of reference numerals
1 coiler 27 optical laser sensor
2 metal strip
3 mandrel
s 4 package/coil
upper feed roller
6 lower feed roller
7 guide plate (guide plate)
8 pressure roller
io 9 strip guide
cylinder
11 upper guide plate
12 cylinder
13 the strip-tension measurer
14 pivot arm
15 guide body
16 roller arm
17 roller
18 pivot
19 retaining element
20 force sensor
21 force axis
22 feeder-controller
23 guide roller
24 pivotal flap
25 measurement output
26 measurement output
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