WO1987007049A1

WO1987007049A1 - Electrical tension adjuster for winding operations

Info

Publication number: WO1987007049A1
Application number: PCT/EP1987/000228
Authority: WO
Inventors: Siegfried Winkelmann; Gerhard FLÖRCHINGER
Original assignee: Zahnradfabrik Friedrichshafen Ag
Priority date: 1986-05-09
Filing date: 1987-04-25
Publication date: 1987-11-19
Also published as: DE3713915A1

Abstract

An electrical device for regulating the tension of a material being wound or unwound onto or from a stationary winding roller revolving around its axis. According to the state of the art, the device consists of an element for measuring the deviation of the tension of the material being wound or unwound from a pre-set specified value, and a controllable adjusting element on the winding roller, serving to vary the driving or braking force. The adjusting element is controlled by a regulator. According to the invention, the adjusting element envisaged for driving or braking the winding roller is a hysteresis coupling or brake, the transmission or braking force of which is infinitely variable. The measurement element consists of two deflection rollers which receive the material, said rollers being supported on a common carrier which is arranged around an axis located in the same centre of gravity as the rollers and can be pivoted against the force of a spring. The material is fed in a loop around both deflection rollers in such a way that the tension exerted by the material causes the carrier to pivot against the force of a spring. Pivoting of the roller carrier is detected electrically and is fed via a regulator for controlling the hysteresis coupling or brake.

Description

Electrical traction control device for winding processes

The invention relates to an electrical traction control device for winding processes.

For winding and unwinding operations, e.g. B. in paper processing machines, textile machines or fiber processing machines, there is a requirement to keep the tensile force in the winding material as constant as possible during the winding and / or transport processes in order to ensure homogeneous processing quality and to avoid tearing off a sensitive winding material in web or strand form . In particular, jerky tensile force peaks must not occur (see e.g. Maschinenmarkt, Würzburg 90 (1984) 92).

In particular, there is the problem of regulating the tensile force in a winding material during the unwinding operations of a band-shaped or strand-shaped winding material from a stationary unwinding roll which can be rotated about its axis. The goods drawn off the unwinding roller must be kept constant with regard to the tensile force exerted on the goods during the entire unwinding process. If the tensile force acting on the material to be wound changes during the unwinding process, the material to be wound undergoes an additional elongation, which can lead to errors in the end product in downstream work processes.

If, for example, when printing on fabrics, the fabrics are pulled off an unwinding roll and fed to the printing rollers, changes in the tensile force in the material to be wound lead to stretching of the fabric, which results in distortions of the print pattern in the finished printed fabrics. Comparable errors occur in the automatic continuous coating of thin-walled films. Changes in tensile force cause elastic stretching of the films, which is reflected in the different coating thicknesses of the end product. But also in winding operations, e.g. B. in fiber processing, different tensile forces in the material to be wound lead to inhomogeneous fiber webs, which necessarily also leads to uneven end products if the initially unevenly wound fiber web is removed again for later processing and possibly even with a strictly constant tensile force.

For the regulation of the tensile force in the winding material during winding and unwinding, control devices have become known which consist of a measuring element for detecting the change in tensile force in the winding material and of an actuator acting on the winding roller, which is regulated by a controller in such a way that the the tensile force attacking the winding material is kept constant during winding or unwinding (see "TIDLAND brake" from TIDLAND GmbH, D-4422 Ahaus or "tensile regulator" from ICM, I-20141 Milano).

The measuring element usually consists of a so-called dancer roll or roller. The roller or roller is held with its axis at the free end of a rocker, the axis of rotation of which is fixed. With such a design, the tensile force exerted on the winding material is determined by the weight acting on the roller or roller and remains unchanged as long as the roller or roller is in an unchanged floating position. When the tensile force changes, the roller or roller is raised or lowered and the movement via the rocker is fed to a measuring element, generally a rotary value transmitter, such as a potentiometer, so that the deviation is immediately available as an electrical signal.

Depending on this signal, the driving force exerted on the take-up reel is then increased or decreased, or the braking action of the brake provided on a take-up reel is increased or decreased until the desired target tensile force is restored in the material to be wound. Regulating devices with friction slip clutches have become known for the control of winding operations. These always have the disadvantage that the difference between static and sliding friction leads to the torque peak when changing from synchronous to slip operation.

Solutions with regulated DC motors are also known. However, these have a high expenditure on equipment and are therefore correspondingly expensive and require a lot of space.

Electromagnetic disc brakes are generally used as adjustable, adjustable brakes for braking an unwinding roll, depending on the tensile force.

Controllers are used to evaluate the tensile force measured via the dancer roll or roller, depending on the permissible tolerances of the tensile force acting on the winding material with a simple two-point characteristic up to a PID characteristic (proportional-integral-differential characteristic).

The use of a dancer roller or roller for measuring the tensile force has the disadvantage that a space requirement is required for the loop with the floating roller or roller, which is not available in many applications. The space requirement is possibly increased if the tractive force should be adjustable in a more or less large area, for example with the aid of a spring balance or the like.

With the electromagnetic disc brakes used for braking the unwinding roller, tensile force peaks can occur in the winding material, particularly in the case of control processes in the lower speed range of the unwinding roller, which result from short-term changes between states of sticking and sliding conditions on the Brake surfaces come from. The tensile force peaks lead to brief stretching of the winding material and, as mentioned, can result in errors in the end product in subsequent operations.

The object of the invention is to provide a tensile force control device for winding processes, the elements of which occur. Tensile force peaks in the winding material can be reliably prevented and can be accommodated with little wear and space-saving in the essential area of the winding roll itself. The device should work reliably and economically and still be simple in construction.

This object is achieved with a device according to the features mentioned in claim 1. The sub-claims contain advantageous developments of a device according to claim 1.

According to the invention, a hysteresis clutch or hysteresis brake is provided as an actuator for changing the rotational movement of the winding roller, i.e. for influencing the driving force on a winding roller or the braking action on an unwinding roller, the hysteresis part of which is preferably coupled to the winding roller and the excitation part of which Stand of the winding roll is connected. A hysteresis clutch or brake enables the torque or braking torque acting on the winding roll to be continuously adapted to the respective requirements by changing the excitation current in the coil of the excitation part. The excitation current is changed via a controller, which receives its input signals from a new type of measuring element for the detection of the tensile force deviation in the winding material (see also: "The hysteresis coupling, a new and versatile drive element", electrotechnical magazine 06.65). According to a further design according to the invention, the measuring element is constructed from two rollers or rollers, which are wound around in opposite directions by the material to be wound. The rollers are rotatably mounted on a common carrier. The carrier itself is pivoted about an axis located in the common center of gravity of the rollers or rollers on the housing of the winding roller against a spring force at least in a predetermined range. The material to be wound is guided in a loop around the rolls or rollers so that they rotate in opposite directions during the winding process. The normal guidance of the winding material is such that the tensile force acts at an approximately right angle on the connecting line of the roller or roller axes, so that this unit is pivoted against a spring force when the tensile force occurring in the winding material is the restoring force of the roller or The spring unit preloading spring force exceeds.

A pivoting of the roller carrier is measured by a sensor in the form of a rotary angle sensor, preferably in the form of a simple potentiometer, and is supplied to the controller as an electrical signal. The respective sampled signal is compared in the controller with a setpoint and converted into a corresponding current change for the excitation coil of the hysteresis clutch or brake.

An embodiment of a control device is explained below in connection with the accompanying drawing. The regulation of the tensile force during an unwinding process is described. The invention is not limited to the combinations of features of the claims. For the specialist, there are further useful combinations of claims and individual claim characteristics from the task. The drawing shows:

1 is a schematic representation of the control process,

2 is a front view of an embodiment of the measuring element,

Fig. 3 shows a longitudinal section through the measuring element according to Fig. 2 and

Fig. 4 is a rear view of the measuring element.

1, the structure and the mode of operation of a control device according to the invention are first explained schematically. It is assumed that the tensile force in an unwinding process should be kept constant by adjusting the braking force acting on the unwinding roller.

In detail, an unwinding roll 2 is shown schematically in the drawing, from which the winding material 3 is drawn off.

The unwinding roll 2 can be braked to a greater or lesser extent with the aid of a hysteresis brake 4 which is only indicated schematically and which is preferably arranged directly on the axis of the unwinding roll.

A measuring element 5 is used to measure the more or less large tensile force exerted on the winding material 3, which is represented by an arrow at the right end of the winding material 3. This measuring element 5 consists of two deflection rollers 6 and 7, which are rotatable on a disk-shaped roller carrier 8 are attached. The winding material 3 is wrapped around the upper roller 6 on the right and guided around the lower roller 7 on the left side. The two rollers rotate in opposite directions when the winding material 3 is pulled off. The roller carrier 8 is pivotally mounted about an axis 22 lying in the common center of gravity of the two rollers 6 and 7 of the disk-shaped roller carrier 8. On the disc-shaped roller carrier 8, a lever 9 is attached, which is biased by a spring 10 so that it tries to turn the unit roller carrier 8, rollers 6 and 7 and lever 9 to the right. If a pull is exerted on the material to be wound, the position shown in the drawing is set approximately, ie, the tensile force in the material to be wound 3 corresponds exactly to the tensile force of the spring 10, which is measured directly or via a sensor (not shown) can.

It can be seen that when the tensile force in the winding material 3 is increased, the lever is pivoted to the left, while when the tensile force is reduced, the lever is returned and finally pivoted to the right.

The position of the lever 9 or the force of the spring 10 is fed as an actual value for the tensile force to a controller 11, which in the selected exemplary embodiment is designed as an electronic analog PID controller. The controller receives the setpoint from an adjustable setpoint generator 12 as a comparison value. The preload can be set by a screw (not shown).

After comparing the actual value and the target value, the controller 11 outputs the corresponding control current for the hysteresis clutch 4 to the latter.

2, 3 and 4, the structural design of a measuring element, as it is generally designated 5 in FIG. 1, is shown in three views. 2 shows the front view, FIG. 3 shows a longitudinal section through the measuring element 5 and FIG. 4 shows the rear view. As already described in the schematic explanation of this measuring element with reference to FIG. 1, two deflection rollers 6 and 7 are each freely rotatable on axes 16 and 17, around which the winding material 3 is guided as shown. The rollers 6 and 7 are rotatably mounted on the common roller carrier 8. The roller carrier itself is rotatably mounted on the axis 22, which is rotatably mounted in roller bearings 23 and 24 in a housing 18. The housing is stationary, possibly connected to the stand of the unwinding roll. The shaft 22 carries the lever arm 9 (FIG. 1), which is pivoted in a section of the housing 18 with the shaft 22.

At the end of the shaft 22, a potentiometer 14 is provided, via which the position of the unit of the rollers 6 and 7 with roller carriers 8 is electrically scanned. The electrical value is fed to the controller 11 (FIG. 1) via an output cable 15.

2 that the material to be wound 3, as already explained with reference to FIG. 1, is guided in a loop around the deflection rollers 6 and 7 in such a way that the deflection rollers rotate in opposite directions during the unwinding process. At the free ends of the lever arm 9, which is held by the shaft 22 of the roller carrier, a tension spring 10, which engages in the tangential direction on the lever arm, is attached, the other end of which is attached to a holding part 20 connected to the housing 18. In the reproduced desired position of the roller carrier, the connecting line through the two roller axes 16 and 17 forms an approximately right angle to the pulling direction of the incoming and outgoing winding material 3, the tensile force corresponding to the tensile force of the spring 10.

FIG. 4 shows the rear view of the measuring element 5 with the parts of potentiometer 14, output cable 15, holding part 20, housing 18, lever arms 9 and spring 10 already explained with reference to FIGS. 2 and 3. The invention was explained on the basis of a specific exemplary embodiment in the case of regulating the tensile force during an unwinding process and, as the dimensions of the rolls 6 and 7 show, strand-like winding material.

For the person skilled in the art, there are constructive modifications that can be carried out according to the same basic principle if, for example, a web-shaped winding material is to be processed. The design of the measuring element itself can also be varied within the scope of the invention. For example, it is possible to generate the restoring force on the shaft 22 of the roller carrier 8 with the aid of a spiral spring instead of the lever arm 9 with tension spring 10. A structural summary of the actual value transmitter and setpoint transmitter, for example directly in the measuring element, is also possible within the scope of the invention.

reference numeral

1

2 winding rolls

3 winding material

4 hysteresis brake

5 measuring element

6 pulley

7 pulley

8 roller carriers

9 lever arm

10 tension spring

11 controllers

12 setpoint adjuster

13

14 potentiometers

15 cables

16 axis

17 axis

18 housing

19 wave

20 holding part

21

22 axis

23 rolling bearings

24 bearings

Claims

Expectations

1. Electrical tensile force control device for winding processes, in particular when unwinding a winding material from a stationary unwinding reel, which can be rotated about its axis, with a measuring element for measuring the deviation of the tensile force in the winding material from a predetermined desired value and the drive or braking force on the winding reel adjusting actuator for driving or braking the winding roller, which can be adjusted by a controller controlled by the measuring element, characterized in that a hysteresis clutch or brake (4) is provided as the actuator for the rotary movement of the winding roller (2).

2. Control device according to claim 1, characterized g e k e n n z e i c h n e t,

- That serve as a measuring element (5) for measuring the tensile force in the winding material (3) two wrapped around the material to be wound, on a common carrier (8) rotatably mounted rollers (6, 7), with a carrier around a in the common center of gravity Rollers fixed axis (22) is pivotally mounted,

- And that the material to be wound (3) is guided in opposite directions around the rollers (6, 7) in such a way that the tensile force acting on the material to be wound (3) causes the carrier (8) to pivot against a spring force,

- And that the measuring element has a sensor that evaluates the pivoting of the roller carrier (8).

3. Control device according to claim 1, characterized in that as a sensor for measuring the pivoting of the roller carrier (8) with the roller carrier (8) coupled rotary encoder is provided.

4. Control device according to claim 1, characterized in that a potentiometer (14) is provided as the angle encoder.

5. Control device according to claim 1, characterized in that as a spring element for biasing the pivoting movement of the roller carrier (8) a tangentially on the roller carrier (8) engaging tension spring (10) is provided, which has its other end on the housing of the unwinding roll (2nd ) and / or the measuring element is attached.

6. Control device according to claim 1, characterized in that the tension of a tension spring (10) is adjustable by means of an adjusting device.

7. Control device according to claim 1, characterized in that a spring element is provided as a spring element for the bias of the pivoting movement of the roller carrier (8) in the axis of rotation of the roller carrier (8).