WIRE ALIGNING MACHINE AND METHOD FOR STRAIGHTENING WIRE OR STRIP MATERIAL

Abstract

A method and a device for straightening wire or strip material using a straightening device comprising aligning rollers which act on opposite sides of the material being passed through in an offset manner and some of which are automatically set on the basis of a model, which has been ascertained using input data of the material, such that the requirements for straightness are satisfied. The position of at least one aligning roller is continuously adapted on the basis of the aforementioned data which is detected while the material passes through the straightening device and which represents the target straightness, wherein the deflection of the material in the Y and Z direction after passing through the assembly of aligning rollers is measured by three sensors arranged along the X axis, and the obtained measurement values are input into the model which controls the setting of the aligning rollers which can be set.

Description

FIELD

The invention relates to a method for straightening wire or strip material by means of a straightening device having aligning rollers engaging offset on opposite sides of the material passing through, some of which are automatically set depending on a model, which has been ascertained on the basis of input data of the material, so that the requirements for the straightness are met, wherein the setting of at least one aligning roller is continuously adapted on the basis of the mentioned data acquired during the passage through the straightening device, which data are representative of the achieved straightness, wherein within the model an X axis lies in the passage direction of the material, and a Y axis and a Z axis lie perpendicular to one another and to the X axis.

The invention furthermore relates to a wire aligning machine or a device for straightening wire or strip material having a dressing device having two rows of non-driven aligning rollers arranged longitudinally offset opposite in relation to one another, which engage in operation on a material passing through between the rows in order to straighten it, wherein some aligning rollers are settable on the material in a manner automatically controlled by a model so that the requirements for the straightness of the material exiting from the straightening device are met, wherein within the model an X axis lies in the passage direction of the material, and a Y axis and a Z axis lie perpendicular to one another and to the X axis.

BACKGROUND

WO 2020/172694 teaches a method and a device, in which a wire can be straightened in an adjustable aligning device. For this purpose, either the temperature of the wire, the forces on the aligning rollers, or the deflection of the aligned free wire after leaving the aligning device are continuously measured, input into a model, and used for adjusting the setting of some aligning rollers to the wire. It is disadvantageous that in the case of the measurement of the wire deflection, a free wire has to be present, which cannot be further processed in an automated manner immediately.

WO 2015/144539 A1 discloses a method in which a relationship, inter alia, of forces which act on aligning rollers and “aligning quality properties” such as the flatness of the material to be aligned, is ascertained within a test measurement. Subsequently, a model is formed which permits the setting of aligning rollers to be adjusted within an aligning process from running aligning quality properties, however, without measuring forces in this case. It is disadvantageous that the method only takes place in the context of a test measurement.

SUMMARY

The invention has the object of specifying a closed control loop for an autonomous method in order to straighten material to be aligned of unknown, variable curvature, wherein the wire end does not have to be free, wherein the aligning machine does not have to be constructed very much longer than is normal, and wherein a separate test measurement pass does not have to be carried out. This is achieved in the method mentioned at the outset in that the deflection of the material after the passage through the arrangement of the aligning rollers in the Y direction and in the Z direction is measured by means of three sensors arranged spaced apart along the X axis of the material and the obtained measured values are input into the model controlling the setting of the settable aligning rollers.

In one embodiment of the method, the wire or the strip material passes through straightening devices in succession, wherein the one straightening device has horizontally arranged aligning rollers and the other has vertically arranged aligning rollers.

In a further advantageous alternative, the material is cut to predetermined lengths after the third sensor viewed in the passage direction.

The measurement of the position of the material takes place after all aligning rollers viewed in the passage direction by measuring the deviation of the material from the passage axis (the X axis) in the setting direction of the aligning rollers (Y axis) and perpendicular to these two axes (the Z axis). Known optical measuring methods by, for example, laser distance sensors (so-called laser scanners) or ultrasonic sensors come into consideration for this purpose. It is conceivable that the position measurement is only carried out at the beginning of the method for calibration purposes, while in running operation, it is sufficient to measure the forces engaging on the aligning rollers to carry out the method according to the invention.

The invention moreover relates to a device for carrying out the method according to the invention. The invention consists in such a device of three sensors spaced apart from one another in the X direction for measuring the deflection of the material in the Z and in the Y direction being arranged after the straightening device viewed in the movement direction of the material, wherein all obtained measured values can be supplied to the model controlling the setting of the settable aligning rollers.

In an alternative of the invention, a wire cutter is arranged after the third sensor viewed in the passage direction.

It is preferred in a further embodiment that the wire passes through two straightening devices in succession, wherein one straightening device has horizontally arranged aligning rollers and the other has vertically arranged aligning rollers.

It is also conceivable in an alternative that after the third sensor viewed in the passage direction, a second straightening device is arranged having two rows of nondriven aligning rollers arranged longitudinally offset in relation to one another, which engage in operation on a material passing between the rows, wherein the second straightening device engages on the material offset by 900 in relation to the first.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail on the basis of the drawings, in which:

FIG. 1 shows a straightening device having a wire passing through it;

FIG. 2 shows the same straightening device having indicated measurement points;

FIG. 3 shows the graphic model of a wire deflection; and

FIG. 4 shows a control loop as a block diagram.

DETAILED DESCRIPTION

The straightening device of FIG. 1, which is part of the prior art, has two rows of horizontal aligning rollers 3, 4, 6, 10 arranged horizontally offset in relation to one another. One row engages on the wire material 1 to be aligned from below and the other row engages on the wire to be aligned from above. The wire material 1 to be aligned can also be strip material (not shown); the expression wire material designates the wire or strip material hereinafter. The aligning rollers 3, 4, 6, 10 have no rotational drive, the wire passes through the straightening device as the material 1, which is moved by feed rollers (not shown) in the direction of the arrow 2. Normally, the wire passes through to straightening devices offset by 90° in relation to one another in succession, wherein one straightening device has horizontal aligning rollers and the other straightening device has vertical aligning rollers. The main working range of the invention comprises wire diameters between approximately 4 mm and approximately 20 mm.

The first two aligning rollers 3 of the lower row in FIG. 1 have fixed axes of rotation. The lower aligning rollers 4 adjoining thereon is individually settable as such to the material 1 passing through by means of a positioning device indicated at 5. The first three aligning rollers 6 of the upper row are jointly settable to the material 1 and are mounted for this purpose on a common carrier 7, which is vertically adjustable by means of a lever 8 by a positioning motor 9. The upper aligning roller 10 adjoining the upper aligning rollers 6 is individually settable as such to the material by means of a positioning device indicated at 11.

FIG. 2 illustrates that after the aligning rollers 3, 4, 6, 10 in the aligning system, three sensors 13, 14, 15 are attached, which determine the position of the aligned wire in the Y direction and in the Z direction (not shown, since it is perpendicular to the plane of the paper). The absolute value and direction of a curvature is still present is determined by the three sensors 13, 14, 15 spaced apart from one another in the X direction. FIG. 3 shows the model for this purpose, wherein the curvature b is related to a predetermined length l. l is a distance section along the X axis which begins after the aligning rollers of the straightening devices. It can also be located between two straightening devices offset or rotated by 90° in relation to one another. Ideally, all three sensors 13, 14, 15 are located in the distance section l.

If the wire has a curvature (for example, b/l>2 mm/m according to FIG. 3) in the cut state, this is already recognizable in the clamped state of the material 1 before the cutter 16 or other elements of the aligning machine. The curvature is not quite as pronounced in the clamped state as after a cut by the cutter 16. However, it can already be recognized on the wire material 1 visible after the first (of possibly two) straightening devices whether a curvature is present or not. It can even be recognized whether a strong curvature is present.

However, the relationship is nonlinear and is also not directly proportional because the wire works against a clamped state and can deviate in all directions. The opinion therefore prevails in the prior art that the curvature of a wire can only be determined with sufficient accuracy when a wire end is free.

Surprisingly, however, the behavior of the wire with curvature may be modeled in the state clamped at both ends. In the method to be applied for this purpose, the curvature of the wire material 1 in the Y direction and in the Z direction is determined from the three position measurements. The curvature b from FIG. 3 becomes a vector in three-dimensional space. This vector is incorporated into a nonlinear model from which a prediction of the actual curvature, which would be compensated by a new setting of the aligning rollers 3, 4, 6, 10, is calculated. Experiments have resulted in a nonlinear model, by which the difference of the actual curvature from the prediction in the range of the mean value of the curvature of the straight wire is sufficiently small, i.e., the prediction is accurate enough to recognize a deviation from the desired aligning result.

With the aid of the curvature prediction, the state assessment in the predictive control loop is achieved according to FIG. 4. The regulation itself is carried out on the basis of a model which maps the deviation in the aligning result on the required setting corrections of the aligning unit.

Claims

1-6. (canceled)

7. A method for straightening wire or strip material by a straightening device having aligning rollers engaging offset on opposite sides of the material passing through, of which some are automatically set in dependence on a model which has been ascertained on the basis of input data of the material so that the requirements for the straightness are met, wherein the setting of at least one aligning roller is continuously adapted on the basis of the mentioned data acquired during the passage through the straightening device, which data are representative for the achieved straightness, wherein within the model an X axis lies in the passage direction of the material, and a Y axis in a Z axis lie perpendicular to one another and to the X axis, wherein the deflection of the material, after the passage through the arrangement of the aligning rollers in the Y direction and in the Z direction, is measured by three sensors arranged spaced apart from one another along the X axis of the material and the obtained measured values are input into the model controlling the setting of the settable aligning rollers.

8. The method as claimed in claim 7, wherein the wire or the strip material passes through two straightening devices in succession, wherein the one straightening device has horizontally arranged aligning rollers and the other has vertically arranged aligning rollers.

9. The method as claimed in claim 7, wherein the material is cut to predetermined lengths after the third sensor viewed in the passage direction.

10. A device for carrying out the method for straightening wire or strip material as claimed in claim 7, having a straightening device having two rows of nondriven aligning rollers arranged longitudinally offset in relation to one another, which engage in operation on a material passing between the rows in order to straighten it, wherein some aligning rollers are settable onto the material automatically controlled in dependence on a model so that the requirements for the straightness of the material exiting from the straightening device are met, wherein within the model an X axis lies in the passage direction of the material, and a Y axis and a Z axis lie perpendicular to one another and to the X axis, wherein three sensors spaced apart from one another in the X direction for measuring the deflection of the material in the X direction and in the Y direction are arranged after the straightening device viewed in the movement direction of the material, wherein all obtained measured values can be supplied to the model controlling the setting of the settable aligning rollers.

11. The device as claimed in claim 10, wherein a wire cutter is arranged after the third sensor viewed in the passage direction.

12. The device as claimed in claim 10, wherein the wire passes through two straightening devices in succession, wherein one straightening device has horizontally arranged aligning rollers and the other has vertically arranged aligning rollers.