GB2114550A - Winding partially cut strip with cutting line aligned in wound coil - Google Patents

Abstract

Strip with partially severed scrap edge portions (16) still frangibly attached thereto, is wound on to a coil (22) so that the cut edges of the strip are aligned. The strip (10) passes past trimming knives (11) which partially sever the edge portion (16) and sensors (14 and 15) measure the lateral position (T) of the knife and the lateral position (E) of the uncut edge of the edge portion (16) adjacent to the knife position (A). The scrap width (T-E) is then recorded. As the strip (10) is about to be wound on to the coil (22) at position (B) the lateral position (R) of uncut edge of scrap portion (16) is sensed by a sensor (20). The scrap width is then determined by reference to the recorded scrap width and the strip travel between points (A) and (B) which is determined from a tachometer (17) attached to a roll (18) over which the strip passes. The actual position of the cut edge of the strip at position (B) is determined and the axial position of the coil (22) adjusted so that the cut edge of the strip on the coil is aligned. The frangible edge is subsequently removed to leave a straight-sided coil. <IMAGE>

Description

SPECIFICATION Method of winding strip material This invention relates to a method of winding strip material, and in particular, though not exclusively, to a method of winding strip metal into coils for shipmentorforsubsequent processing.

Rolling faults cause variiations in the width of the strip and produce an uneven or ragged edge on the strip. It is desirable to have strip with straight edges, particularwhen coiled. To produce strip of constant width and with a uniform smooth edge, the uneven edge of scrap portions ofthe strip are trimmed off.

This may be done moving the strip past a trimming knife. Trimmed strip can be conveniently coiled on to a coil or mandrel so that a straight sided is produced, e.g. by aligning the tension coil or mandrel so that the edge ofthe strip being coiled is aligned with the edge of the strip already coiled. However, there are problems associated with the production of such strip; for example, the continuously produced ragged scrap portions are difficult to handle and a dangerous situation may occur if the strip narrows so much that the trimming knife runs off the edge ofthe strip.

Some such problems are avoided by processes of edge trimming which involve paartiallysevering the scrap portion from the strip, so that the scrap portion remains frangibly attached to the strip and can be removed at a later stage, e.g. when the strip has been coiled. Methods of partially slitting strip so as to produce strip in which the slit strip edges are connected together at intervals are described in U.K.

Patent Specification 1566741.Such methods suffer from the disadvantage that, if the edges of the strip and coil are aligned by the conventional method already mentioned, when the scrap portions are removed the resulting trimmed coil will be left with sides which are not straight According to this invention there is provided a method of winding strip material on to a coil or mandrel, in which the strip has at least one scrap edge portion partially severed by a trimming knife along a straight line, in such a way that the scrap portion is frangibly attached to the strap, comprising:: producing a continuous record of the width of the scrap portion at a position A of the knife; determining the lateral position R ofthe outer edgs of the scrap portion as the strip is about to be wound on to the coil or mandrel ata position B; determining the appropriate measured width ofthe scrap portion at position B by reference to the record of scrap portion width and the length of strip between the pointsAand B; determining the actual position (R-scrap width) of the cut straight edge of the strip at the position B; and controlling the axial position of the coil or mandrel so thatthe strip will be wound to produce a coil with the cut edge of the strip in alignment.

Preferablythe width of the scrap portion is found by taking a continuous series of measurements ofthe lateral position T of the trimming knife orthe straight edge of the strip, at or adjacent to a position Aof the knife; taking a corresponding series of measurements of the lateral position E of the adjacent outer edge of the scrap portion, and producing a record of E -T. Alternatively the scrap width may be determined by taking a continuous series of measurements of the position of the edge of the strip relative to the trimming knife at or adjacent thereto, which relative position is effectively a measurement of the scrap width (E-T).

Both edges of the strip may be subjected to the trimming operation but it is only necessary to carry out the measurements referred to above at one edge of the strip.

Preferably the method is applied to a metal strip such as, for example, tin plate or stainless steel strip, and it may be applied either at the end of a production line where the strip isto be coiled for transporting away or in the course of production where for example a pickling or other operation is to be carried out and the strip has to be re-wound in coil form.

The length of the strip between the points A and B may be determined by for example use of a digital tachometer driven by a roller over which the strip passes at some stage. If strip is in firm nonslipping contact with the roll an accurate digital representation of the length of the strip between the points A and B wiill be produced.

The measurementT may be either effected at the trimming knife or at the trimmed straight edge adjacentthe trimming knife. Measurement E should be as close as reasonably possible to the measure mont T although in practice the error involved in taking the measu rement E a few centi meters away from the measu rement T along the strip will not be large enough to affectthe end result.

Preferably the measurements are produced on a continuous basis i.e. the data from measurements E, T and R and fed into a microcomputer and the microcomputer carries outthe calculation R- (E-T) on a continuous basis and feeds the continuous series of signals to a controller or an actuator by which the coil or mandrel is moved laterally so as to align with the incoming straight edge of the strip on a continuous basis.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 isadiagrammaticsideelevation ofpartof a production line in which a metal strip is being trimmedandwoundontoatension reel; Figure 2 is a plan ofthe same appartus; Figure 3 is an enlarged portion ofthe edge ofthe metal strip showing the partially severed scrap portion; Figure 4 is a block diagram which shows a measurement and contro circuit including a microcomputer.

Figure 5a is an elevation of a modified form of the invention; and Figure 5b is a plan view of the same.

In Figures 1 and 2, a strip 10 is illustrated as moving This print embodies corrections made under Section 117(1) of the Patents Act 1977.

from left to right and passes through two pairs of trimmer knives 8,9, one pair located towards each side ofthe strip. Each pair of trimmer knives 8,9 consists of top and bottom rotary knives 11 and 12 and the two pairs are used to cut straight edges 13 which are partially severed on each side of the strip 10. From Figure 3 itwill be seen thatthe top and bottom knives are laterally off-set. The gap between thetopknifeandthebottom knife is lessthan the thickness of the strip andforthin stripthe blades may even overlap one another. The knives act in similar fashiontoscissorsto shear and cutthe strip.

The circular part of the knives shearthe strip but the circumference of the knives if relieved by means of machined "flats" and the strip is not severed because of the increased gap at these flats.

A position sensor 14 is used to sense the position T of the trimmer knife 11 at position A of the strip. An adjacent position sensor 15 is used to sense the position ofthe uncut edge E ofthe scrap portion 16. A digital tachometer 17 driven by a roll 18 in contact with the surface ofthe strip 10 produces a pulse output continuoulsy, which is indicative of the length of strip travel between the position A and a position B at which a further measurement R is made indicating the position of the outer lateral edge of scrap portion 16. The number of pulses N2 recorded on the digital tachometer is an indication ofthe length of the strip which may be a considerable length e.g. 100 metres or more.Aswill be seen in Figure3theedge portion 16 remains attached to the strip 10 by spaced frangible interconnecting pieces 19 which may be produced by the methods described in U.K. Patent Specification 1566741. The edge position R is determined by a sensor 20, and all of the signals produced bythe position sensors 14, 15 and 20 are fed to a microcomputer 21 as illustrated in Figure 4, i.e. the signals T, Eand Rare fed to the microcomputer. The output of digital tachometer 17 is also provided to the microcomputer21.

The microcomputer 21 determines and records the scrap width as (E-T) atthe position A. As the strip approaches the reel 22, the sensor 20 indicates the position R of the scrap edge to the microcomputer which then determines the width of the scrap portion (E-T) by reference to the signals from the digital tachometer 17 and the recorded scrap width (E-T) and then determines the position of the straight (trimmed) edge as R -- (E --T). The microcomputer produces a signal corresponding to the determined function, which is fed to an actuator 23 by which the lateral position of reel 22 is controlled. Thus the reel is aligned so asto produce a continuously wound strip with the trimmed or cut edges in alignment.

The strip edge position E and the knife position T are measured at points asclosetogetheras possible to avoid errors. In practice because the trimmer moves only a small amount any error is insignificant providing the edge position E and knife position Tare within a few centimeters of each other. Even if the sensors 14 and 15 are not close together any error can be corrected by combining the signal E with a signal T delayed by a number N1 pulses of the tachometer.

If strip shown in the drawings has just come through a pickling bath, then after coiling on to the reel 22 the coil will be removed from the pickle line and transported to its next stage of processing which mayfor example be a cold rolling mill. At some appropriate position on the conveyors between the pickle line and the cold mill there may be a station provided where the edge scrap is removed from the coil.

In the modification shown in Figure 5 a single edge sensors 24 may be mounted on the trimmer head 25 itself. The advantage of this arrangement is that the edge sensor 24 moves with the trimmer head 25. The edge sensor will detectthe edge ofthe strip and in effect it detects the position of the strip in relation to the trimmer itself and hence in relation to the cut made by the knife. In effect, this one sensor measures the scrap width (E -T) directly. This system thus requires only one sensor instead of two sensors as previously required.

Claims (15)

1. A method of winding strip material on to a coil or mandrel, in which the strip has at least one scrap edge portion partially severed by a trimming knife along a straight line in such a waythatthe scrap portion is frangibly attached to the strip, comprising: Producing a continuous record ofthewidth of the scrap portion ata positionAofthe knife; determining the lateral position R ofthe outer edge ofthe scrap portion as the strip is aboutto be wound on to the coil or mandrel ata position B; determining the appropriate measured width ofthe scrap portion at postion B by reference to the record of scrap portion width and the length of strip between the points A and B;; determining the actual position (R-scrap width) of the cut straight edge of the strip atthe position B; and controlling the axial position ofthe coil or mandrel sothatthestripwill bewoundto produce a coil with the cut edge of the strip in alignment.

2. A method as claimed in claim 1 wherein the width ofthescrap portion is found by taking a continuous series of measurements of the lateral position T ofthe trimming knife orthe straight edge of the strip, at or adjacent to a position A of the knife; taking a corresponding series of measurements of the lateral position E ofthe adjacent outer edge of the scrap portion and producing a record of E-T.

3. A method as claimed in claim 2 wherein the measured lateral position T of the trimming knife or thestraightedgeofthestripandthemeasured lateral position E of the adjacent outer edge ofthe scrap portion are supplied as data to a computerwhich determines and records the width (E-T) of the scrap portion.

4. A method as claimed in claim3wherein the determined lateral position R of the outer edge ofthe scrap portion atthe position B and information indicative of the length of strip between the points A and B are supplied as data to the computer which calculates the length of the strip between the points A and B and determines the appropriate of the recorded scrap portion widths, and then determines the actual position R-(E-T) ofthe cut edge of the strip.

5. A method as claimed in claim 1 wherein the scrap width is determined bytaking a continuous series of measurements ofthe position ofthe edge of the strip relative to the trimming knife at or adjacent thereto.

6. A method as claimed in claim 5 wherein the measured relative position or scrap width is con tinuouslysupplied as data to a microcomputerwhich records the data, and then uses the recorded data in conjunction with the calculated or measured length of strip between positions A and B to determine the appropriate scrap portion in width to be used with the lateral edge position R.

7. A method as claimed in claim 4 or 6wherein the computer produces a control signal to operate an actuator orthe like which moves the coil or mandrel laterallyso that cut edge is aligned.

8. A method as claimed in claim 1,2 or3 wherein the amount of strip travel between the points A and B is determined by using a digital tachometer driven by a roll overwhich the strip passes.

9. A method of winding strip material substantially as herein described, with reference to Figures 1 to 4, or Figures 5a and 5b of the drawings.

10. An apparatus for winding strip material on to a coil or mandrel, the strip material having at least one scrap portion partially severed by a trimming knife along a straight line in such a way that the scrap portion isfrangibly attached to the strip, comprising: means for producing a continuous record ofthe width of the scrap portion at a position A ofthe knife; a sensorforsensing the lateral position R ofthe outer edge ofthe scrap portion as the strip is about to be wound on to the coil or mandrel at a position B; means for determining the appropriate measured width of the scrap portion at position B by reference to the record of scrap portion width and the length of strip between points A and B;; means for determining the actual position of the cut straight edge ofthe strip at position from the sensed lateral position R and the appropriate scrap width; and control means responsive to the position determining means,forcontrollingtheaxialpositionofthecoil or mandrel so that the strip will be wound to produce a coil with the cut edge of the strip in alignment.

11. An apparatus as claimed in claim 10 wherein the record producing means includes a sensor for sensing the lateral portion T ofthe trimming knife, and a sensorforsensing the lateral position E of the uncut scrap edge, and also includes means for determining and recording the difference between the two sensed positions (E-T).

12. An apparatus as claimed in claim 10 wherein the record producing means includes a sensor mounted with the trimming knife for sensing the position of uncut scrap edge relative to the knife, and thus the scrap width.

13. An apparatus as claimed in claim 10,11 or 12 wherein a computer records the scrap width atthe position A, determines the actual position ofthe cut edge at position B and supplies a control signal to the control means so as to align the strip as the strip is wound.

14. An apparatus as claimed in any one of claims 10 to 13 wherein a digital tachometer connected to a roll over which the strip passes, is used to determine the amount of strip travel between the points A and B.

15. An apparatus for winding strip material sub stantial ly as herein described, with reference to Figures 1 to 4, or Figures 5a and 5b ofthe drawings.