Winding apparatus for paper webs and method of winding paper webs

The winding apparatus (1) for a paper, textile, plastic or other material web (2) comprises a reel drive apparatus (5) for driving a reel (3), in order to convey the web (2) in a feed direction (Z) and to wind it onto the reel (3), and a web tension roll (12), which is arranged upstream of the reel (3) in the feed direction (Z), in order to produce a tension which acts on the web (2) counter to the feed direction (Z), the web tension roll (12) being coupled to a drive apparatus (15), the drive apparatus (15) comprising a clutch (20) and a drive (17), the clutch (20) being operatively arranged between the drive (17) and the web tension roll (12), and the clutch (20) permitting slip between the drive (17) and the web tension roll (12).

The invention relates to a winding apparatus for paper, textile, plastic or 
other material webs and to a method of winding such webs. 
It is known to wind paper, textile, plastic or other material webs onto a 
reel, and then to feed them, by unwinding the reel, to a further 
processing process, such as a printing, cutting or packing apparatus. 
A central function during the winding of a reel is the production of a 
tensile force on the web. The winding quality and, associated with this, 
the unwinding characteristics of the reel are strongly influenced by the 
web tension that is present during the winding operation. 
The object of the present invention is to propose a winding apparatus for 
paper, textile, plastic or other material webs which has more advantageous 
winding characteristics, and/or allows a tension acting on the web to be 
produced more advantageously. 
The object is in particular achieved with a winding apparatus, for a paper, 
textile, plastic or other material web, which comprises a reel drive 
apparatus for driving a reel, in order to convey the web in a feed 
direction and to wind it onto the reel, and a web tension roll, which is 
arranged upstream of the reel in the feed direction, in order to produce a 
tension which acts on the web counter to the feed direction, the web 
tension roll being coupled to a drive apparatus, the drive apparatus 
comprising a self-locking mechanism and a drive, and the self-locking 
mechanism being operatively arranged between the drive and the web tension 
roll. 
The operative arrangement of the self-locking mechanism between the web 
tension roll and the drive has the advantage that, by means of an 
appropriately controlled speed of the drive of the web tension roll, 
braking energy can be extracted via the self-locking mechanism, it being 
possible for the extracted braking energy to be dissipated via the housing 
of the self-locking mechanism. 
In an advantageous embodiment, the drive apparatus has a clutch that is 
operatively arranged between the web tension roll and the drive. 
The object is in particular further achieved with a winding apparatus, for 
a paper, textile, plastic or other material web, which comprises a reel 
drive apparatus for driving a reel, in order to convey the web in a feed 
direction and to wind it onto the reel, and a web tension roll, which is 
arranged upstream of the reel in the feed direction, in order to produce a 
tension which acts on the web counter to the feed direction, the web 
tension roll being coupled to a drive apparatus and the drive apparatus 
comprising a clutch and a drive, so that the clutch is operatively 
arranged between the drive and the web tension roll, and the clutch 
permits slip between the drive and the web tension roll. 
Neither friction nor slip must occur between the web tension roll and the 
conveyed web, in order not to damage the web, which consists of paper, for 
example, or the imprint on the web. 
One advantage of the inventive winding apparatus is to be seen in the fact 
that a tensile force can be produced on the paper web even when the latter 
is at a standstill. The drive apparatus applies a torque to the web 
tension roll which acts counter to the conveying direction, the clutch 
that is arranged between the drive and the web tension roll being operated 
with slip and, at the same time, the speed of the drive and/or the slip of 
the clutch being controlled in such a way that the web tension roll 
remains stationary. 
In a preferred embodiment, the drive acting on the web tension roll is 
configured as a controllable, variable-speed motor. In a further preferred 
embodiment, the clutch has means which can be controlled, for example 
magnetically or pneumatically, in order to control the maximum 
transmissible torque, so that the slip can be controlled with the aid of a 
control device. 
In a particularly advantageous embodiment, the self-locking mechanism is 
arranged between the drive and the clutch. One advantage of this 
embodiment is to be seen in the fact that the self-locking mechanism is 
used, inter alia, to dissipate the braking energy that is extracted from 
the web tension roll, via the self-locking mechanism, to a stationary 
housing. In this case, the speed of the drive is advantageously controlled 
in such a way that the clutch has a relatively low slip of, for example, 
5% to 10%, so that in the clutch, on the one hand, a relatively small 
amount of frictional heat is produced, and therefore the clutch, on the 
other hand, can also be dimensioned to be relatively small. Since the 
self-locking mechanism conducts a large part of the braking energy to the 
housing, a drive motor having a small power is sufficient. In an 
advantageous refinement, the drive motor is configured as a small, 
asynchronous motor whose speed may be controlled with a power controller. 
A power controller is also referred to as a frequency converter. 
The speed of the drive motor is, for example, controlled in such a way that 
the clutch always has a slip of 5%, the drive motor acting in the same 
direction as the movement of the web at relatively high web speeds, and 
the drive motor being driven in the opposite direction at very low web 
speeds, in particular when the web is at a standstill, so that a tensile 
force is applied to the web via the web tension roll even when the web is 
at a standstill. 
In an advantageous refinement, the self-locking mechanism is configured as 
a worm-drive mechanism. 
The reel onto which the paper web is wound can be driven at the center or 
at its periphery.

The winding apparatus 1 which is illustrated schematically according to 
FIG. 1 is used to wind a paper web 2 onto a reel 3. The reel 3, which is 
mounted on a winder shaft 4, is driven by a reel drive apparatus 5, so 
that the web 2 is moved in a feed direction Z. The reel drive apparatus 5 
comprises a motor 6, which on one side is connected via a toothed belt 7 
to the winder shaft 4, in order to drive the latter, and on the other side 
is connected via an electric line 8 to a frequency converter 9. The motor 
6 is configured as an AC motor, and the frequency converter 9 comprises 
power electronics which are suitable to generate a rotating field in order 
to drive the AC motor 6. The motor 6 is connected via a further toothed 
belt 10 to a sensor 11 for measuring the motor speed D. The sensor 11 
could also be arranged at a different point, for example inside the motor 
6 or at the winder shaft 4, in order to measure the rotational speed. A 
web tension roll 12 is placed upstream of the reel 3, in the feed 
direction Z, the two turn rolls 13, 14 being arranged in such a way in 
relation to the web tension roll 12 that the web 2 is in contact with the 
web tension roll 12 over a portion of the circumference of the latter. The 
web tension roll 12 is used for the purpose of producing, on that section 
of the web 2 which follows the web tension roll 12, a web tension which 
acts counter to the feed direction Z. The web tension roll 12 is designed 
and is operated in such a way that that portion of the web 2 which rests 
on the web tension roll 12 follows the movement of the web tension roll 12 
without slip. This prevents any friction or any mutual relative movement 
between the web tension roll 12 and the paper web 2, which could otherwise 
damage the paper web 2 or an imprint on the paper. In the exemplary 
embodiment illustrated, the web tension roll 12 has a rubber-covered 
surface. The maximum producible web tension depends, inter alia, on the 
wrap angle of the web 2 around the web tension roll 12, so that with a 
large wrap angle, a correspondingly large, maximum web tension can be 
produced, the condition always having to be satisfied that no slip or no 
sliding occurs between the web tension roll 12 and the paper web 2. The 
rotational speed of the web tension roll 12 is thus determined by the web 
speed vz of the web 2. A drive apparatus 15 which acts on the web tension 
roll 12 is used to impart a torque, which acts counter to the feed 
direction Z, to the web tension roll 12, the maximum torque being 
determined by the requirement that no slip must occur between the paper 
web 2 and the web tension roll 12. The drive apparatus 15 comprises a 
variable-speed motor 17, which can be controlled via a frequency converter 
16, and which in turn is configured as an AC motor. The shaft of the motor 
17 is connected to a clutch 20 via a self-locking mechanism, that is, 
self-locking gear mechanism, 18 and a toothed belt 19. The clutch 20 has 
two concentrically arranged pulleys 22, 23, and permits the slip between 
the pulleys 22, 23 to be influenced. The clutch 20 is connected to the web 
tension roll 12 via the pulley 23 and a toothed belt 21. The clutch 20 
comprises a controllable friction clutch, which, for example, is 
configured such that it can be controlled magnetically or pneumatically, 
in order to produce a controllable slip between the web tension roll 12 
and the motor 17. A control device 24 is provided in order to control the 
winding apparatus 1, and is connected via a data bus 25 to further control 
devices or a higher-order computer. The frequency converters 9, 16 are 
controlled via electric signal lines 26, 27. The motor 17 is connected to 
the frequency converter 16 via a connecting line 43. The braking force of 
the controllable friction clutch 20 is controlled via an electric signal 
line 28. The speed vz of the web 2 is sensed by a sensor 29, and fed to 
the control device 24 via an electric signal line 30. The rotational speed 
D, registered by the sensor 11, of the motor 6 or of the winder shaft 4 is 
fed to the control device 24 via a signal line 31. Since the motor 6 is 
rigidly coupled to the winder shaft 4 via the toothed belt 7 or a further 
mechanism, it is possible for both the rotational speed of the motor 6 and 
the rotational speed of the winder shaft 4 to be calculated from the 
signal of the sensor 11. 
During the operation of the apparatus according to FIG. 1, the motor 6 
drives the reel 3 in the feed direction Z, so that the web 2 is conveyed 
in the feed direction Z at a web speed vz. The tensile force acting on the 
web 2 is produced by the web tension roll 12. The braking force, and hence 
the web tension, can be set by means of parameters on the control and 
regulating device 24. The clutch 20 is controlled directly by the control 
device 24, using pulse width modulation, in such a way that the set 
braking force is produced. In order to reduce the friction losses and the 
wear on the clutch 20, the latter is made to follow at reduced speed by 
the motor 17, via a self-locking mechanism 18. In order to maintain or to 
build up the web tension, even when the web 2 is at a standstill, the 
motor 17 and the pulley 22 of the clutch 20 are rotated slowly backwards. 
When the web 2 is at a standstill, the drive apparatus 15 is operated in 
such a way that the clutch 20 applies a torque to the web tension roll 12, 
the web tension roll 12 remaining at a standstill. The motor 17 transmits 
a torque to the clutch 20, the speed of the motor 17 and/or the clutch 20 
being controlled, via the electric lines 26, 28, in such a way that the 
clutch 20 has a slip such that the web tension roll 12 remains at a 
standstill. With increasing web speed vz, the speed of the motor 17 or the 
braking force of the clutch 20 is, for example, continuously made to 
follow in such a way that the clutch 20 has a slip of about 5%, 
irrespective of its rotational speed. The braking energy extracted from 
the web tension roll 12 is fed via the clutch 20 to the self-locking 
mechanism 18, which is illustrated only schematically, which produces a 
countertorque and conducts the energy to a housing (not illustrated). By 
using a self-locking mechanism 18 of this type, it is necessary for the 
motor 17 to produce only a relatively small torque, and it can therefore 
be operated at low power. The slip of the clutch 20 is kept to a 
relatively small value of, for example, 2% to 10%, for which reason the 
frictional heat generated in the clutch 20 is low, so that a small and 
correspondingly cost-effective clutch 20 can be used. This ensures 
low-energy braking of the web 2. 
The web speed vz, which is measured by the sensor 29, a measuring wheel, 
and the rotational speed of the reel 3, which can be calculated via the 
sensor 11, can be used by the control device 24 to calculate the diameter 
of the reel. The motor 17 is controlled via a frequency converter 16 in 
such a way that, at a small diameter of the reel 3, a high tension is 
produced in the web 2, and at a large diameter of the reel 3, a smaller 
tension is produced in the web 2. In particular when starting the winding 
operation, the reel 3 has a very small diameter, so that a high web 
tension is necessary. 
FIG. 1a shows the clutch 20 from the viewing direction B, the toothed belt 
19, 21 running over the pulleys 22, 23 not being illustrated. The two 
pulleys 22, 23 are arranged mounted alongside each other so that they can 
rotate about the common axis A, the clutch 20 having additional means (not 
illustrated) in order to couple the two pulleys 22, 23 to each other in a 
controllable manner. 
In a further exemplary embodiment, it would be possible to dispense with 
the clutch 20 in the winding apparatus 1 according to FIG. 1, by the web 
tension roll 12 being driven directly by the motor 17, via a toothed belt 
19, using a self-locking mechanism 18. As compared with this solution, the 
use of a clutch 20 has the advantage that the clutch 20 permits speed 
fluctuations between the web tension roll 12 and mechanism 18 to be 
compensated in a simple way, since the clutch is simple to control and 
regulate. 
The side view illustrated in FIG. 2 of a further winding apparatus 1, a 
cross section along the line A--A according to FIG. 3, illustrates a 
housing 32, in which the winder shaft 4, the web tension roll 12 and the 
turn rolls 13, 14 are arranged. In this exemplary embodiment, the turn 
rolls 13, 14 press the paper web 2 directly onto the rubber-covered 
surface of the web tension roll 12. The turn rolls 13, 14 could also be 
arranged in such a way that the turn roll 13 or 14 presses onto the web 
tension roll 12, whereas the other turn roll 14 or 13 is arranged at a 
distance from the surface of the web tension roll 12. Arranged upstream of 
the web tension roll 12 in the feed direction Z is a storage device 33, a 
so-called dancer. The storage device 33 has two turn rolls 34, between 
which a supply of the paper web 2 is stored. Using a number of optical 
sensors 35, the stored length of the paper web 2 is registered, and this 
measured variable is fed to the control device 24 via an electric signal 
line, for example the line 25. 
From the plan view according to FIG. 3, it is possible to see the reel 1, 
mounted at its center, with the winder shaft 4. The winder shaft 4 is 
driven by the motor 6 via a toothed belt 7 and a further torque 
transmission device 36, which is configured as a multistage gear 
mechanism. The drive apparatus 15 which acts on the web tension roll 12 
comprises a motor 17, whose shaft is connected to the self-locking 
mechanism 18, which is designed as a worm-gear mechanism. The output shaft 
of the self-locking mechanism 18 is connected to the clutch 20. The clutch 
20 is connected to the web tension roll 12 via a further shaft. The 
mechanism 18 is firmly connected to the housing 32. 
The exemplary embodiment according to FIGS. 2 and 3 is operated in such a 
way that the sensors 35 are used to register the length of the web 2 
stored in the storage device 33, and this value is fed to the control and 
regulating device 24. Using a higher-order control loop, the rotational 
speed of the reel 3, or the winding speed, is controlled via the motor 6 
in such a way that there is always approximately the same stored length in 
the storage device 33. Using a nested control loop, the motor 17 and/or 
the clutch 20 are controlled in such a way that the slip in the clutch 20 
is, for example, always 5%, and, depending on the diameter of the reel 3, 
the tension previously set in the control device 24 is produced in the web 
2. 
FIG. 4 shows an exemplary embodiment of a passively acting clutch 20. The 
winder shaft 4 has a shaft extension 38, which is connected to the housing 
32 via a ball bearing 37. The clutch disk 39, forming a component of the 
clutch 20, is firmly connected to the shaft extension 38. A clutch pulley 
40, forming a further component of the clutch 20, is rotatably connected 
to the shaft extension 38 via a ball bearing 41. The toothed belt 19 acts 
on the periphery of the clutch pulley 40. The clutch pulley 40 has a 
friction lining 42 which, in the event of slip, has a rotational speed 
that differs from the clutch disk 39, and transmits a torque to the clutch 
disk 39. The clutch 20 may also comprise further, active means (not 
illustrated), such as an electromagnetic or a pneumatically acting means, 
in order to influence the contact force between the clutch disk 39 and the 
clutch pulley 40 in a controlled manner. 
In all the exemplary embodiments illustrated, the reel 3 is illustrated as 
rotating to the right in relation to the feed direction Z. The web 2 could 
of course also be fed running in such a way that the web 2 is wound up by 
a reel 3 rotating to the left. 
FIGS. 5a and 5b show an exemplary embodiment of a self-locking mechanism 18 
configured as a worm-drive mechanism. The mechanism 18 comprises a housing 
18a, on which two shafts 18c, 18f are mounted by means of ball bearings 
18b. Fastened to the first shaft 18c is a sleeve 18d having a ring gear 
18e, which engages in a worm 18g on the second shaft 18f. If this 
self-locking mechanism 18 is used in the exemplary embodiment of FIG. 3, 
the motor 17 drives the second shaft 18f, whereas the clutch 20 is 
connected to the first shaft 18c. A large part of the energy transmitted 
from the clutch 20 to the self-locking mechanism 18 is converted into heat 
via the worm 18g and the ring gear 18e, so that a motor 17 of relatively 
low power is sufficient to drive the second shaft 18f in such a way that a 
braking action is produced on the web tension roll 12.