US3421710A - Unwinding apparatus - Google Patents

Unwinding apparatus Download PDF

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Publication number
US3421710A
US3421710A US582291A US3421710DA US3421710A US 3421710 A US3421710 A US 3421710A US 582291 A US582291 A US 582291A US 3421710D A US3421710D A US 3421710DA US 3421710 A US3421710 A US 3421710A
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US
United States
Prior art keywords
speed
brake
current
characteristic
reel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US582291A
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English (en)
Inventor
Gerhard Mier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Alcan Holdings Switzerland AG
Original Assignee
Alusuisse Holdings AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CH1344765A external-priority patent/CH440899A/de
Application filed by Alusuisse Holdings AG filed Critical Alusuisse Holdings AG
Application granted granted Critical
Publication of US3421710A publication Critical patent/US3421710A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C47/00—Winding-up, coiling or winding-off metal wire, metal band or other flexible metal material characterised by features relevant to metal processing only
    • B21C47/34—Feeding or guiding devices not specially adapted to a particular type of apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C47/00—Winding-up, coiling or winding-off metal wire, metal band or other flexible metal material characterised by features relevant to metal processing only
    • B21C47/003—Regulation of tension or speed; Braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H23/00—Registering, tensioning, smoothing or guiding webs
    • B65H23/04—Registering, tensioning, smoothing or guiding webs longitudinally
    • B65H23/06—Registering, tensioning, smoothing or guiding webs longitudinally by retarding devices, e.g. acting on web-roll spindle
    • B65H23/063—Registering, tensioning, smoothing or guiding webs longitudinally by retarding devices, e.g. acting on web-roll spindle and controlling web tension
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H59/00—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators
    • B65H59/02—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators by regulating delivery of material from supply package
    • B65H59/04—Adjusting or controlling tension in filamentary material, e.g. for preventing snarling; Applications of tension indicators by regulating delivery of material from supply package by devices acting on package or support

Definitions

  • the pole wheel magnet brake In controlling the tension of unwinding material, the pole wheel magnet brake is drawn in a direction opposite to that of a reel shaft at a speed which, with the reel shaft stationary, is sufiicient to reach the point of maximum torque, on the torque-speed characteristic, at the initial value of the brake coil current; thereafter, in the period between the commencement of unwinding and the attainment of full speed of the unwound material the brake coil current is regulated in accordance with the speed of the unwound material so that the current/ speed characteristic for the brake has a positive slope; and is made zero or negative.
  • the invention relates to apparatus for controlling the tension in the unwound material in unwinding arrangements employing an electromagnetic brake (induction or eddy-current brake) with an approximately hyperbolic torque-speed characteristic. It is desirable so to control the arrangement that the desired tensile stress of the strip material remains constant throughout the unwinding operation.
  • an electromagnetic brake induction or eddy-current brake
  • the problem posed in unwinding arrangements generally consists in obtaining as constant a tensile stress as possible irrespective of the winding diameter.
  • the degree of accuracy with which the tensile stress is to be maintained varies considerably.
  • Control arrangements for electro-magnetic brakes which efiect regulation to constant unwinding capacity and keep the tensile stress on the strip material constant at constant speed of the strip.
  • On acceleration and deceleration however, deviations from the desired strip tension occur. Such deviations are not permissible in many cases, in particular in the case of easily damaged strip material or when a large inertial mass is provided by the wound coil.
  • control or regulating arrangements for unwinders which measure the tensile stress of the strip material directly and use this quantity for regulation purposes.
  • the tensile stress is kept constant irrespective of the winding diameter and of acceleration and deceleration processes.
  • the use of these strip tension measuring arrangements leads to additional expenditure for example for pressure-measuring capsules, tension adjusting rolls or pressure rollers which are additionally undesirable in many cases for reasons of space or because of special surface sensitivity of the strip material.
  • control arrangements for electromagnetic brakes are known which regulate strip tension by means of apparatus for mechanically or optically scanning the reel diameter. The drawback in these arrangements also resides in the additional expenditure on construction or in a certain hindrance in the operation of the machine.
  • the present invention avoids this additional expenditure and the drawbacks associated therewith and nevertheless produces a substantially constant strip tension throughout the unwinding operation by employing electromagnetic brakes, known in themselves, of a kind having a torquespeed characteristic which after reaching a maximum torque as the speed increases from zero falls approximately hyperbolically. Direct measurement of the tensile stress and the winding diameter is deliberately avoided.
  • the pole wheel of the brake is driven in a direction opposite to that of the reel shaft at a speed which, with the reel shaft stationary, is sufiicient to reach the point of maximum torque, on the torque-speed characteristic, at the initial value of the brake coil current; thereafter, in the period between the commencement of unwinding and the attainment of full speed of the unwound material the brake coil current is regulated in accordance with the speed of the unwound material so that the current/speed characteristic for the brake has a positive slope; and the current is then either maintained constant with increasing reel speed as the diameter of the wound material decreases, or the current is reduced as the reel speed increases.
  • An electric signal derived from a tachometer connected to draw rollers for withdrawing wound material from the reel can be added to a constant signal and then used to control the brake coil current during the period of running up to full speed of the unwound material.
  • FIGURE 1 shows the circuit and arrangement of a first apparatus
  • FIGURE 2 shows the circuit and arrangement of a second form of apparatus
  • FIGURE 3 shows the torque-speed characteristic of the brake
  • FIGURE 4 shows the coil-current/speed characteristic of the controlled brake
  • FIGURE 5 illustrates the resistance curve for the acceleration and deceleration circuit
  • FIGURE 6 shows the coil current/speed characteristic of the brake for the second form of apparatus.
  • the strip material is drawn from the winding-off reel 2 by the driving rollers 1.
  • An electro-magnetic brake 3 (an eddy-current or induction brake) is connected to the reel shaft. It consists of two rotatably mounted halves, the socalled pole wheel 3a and the armature.
  • the torque is transmitted by magnetic force and can be regulated by means of the current in the coil 4.
  • the different values of current strength in the coil lead to a family of curves for the torque-speed characteristic of the electro-magnetic brake. These curves all have a form generally similar to that shown in FIGURE 3 and vary only by their ordinates, smaller values of the current corresponding to smaller values of torque.
  • One half of the eddy-current or induction brake is coupled to the reel shaft and the other half is driven at constant speed in the direction opposite to the direction of wind-off by a geared three-phase electric motor 5.
  • the speed is preferably so calculated that it is located at the turning point of the torque speed characteristic of FIGURE 3, in which the speed is the relative speed of the two brake parts.
  • the coil 4 is fed by an amplifier 6.
  • the amplifier contains a current-regulating means which compares nominal and actual values and which ensures that the coil current is not alfected by the heating of the coil and the increase in the ohmic resistance that is associated therewith.
  • Rotary resistors 7, 8 and 9 are located in the input circuit of the amplifier 6.
  • the rotary resistors 7 and 8 are mechanically coupled to one another and are adjusted to the initial winding diameter by means of a manually-operated rotary knob.
  • the resistor 9 serves to adjust the desired winding tension and is connected in series with further resistors 10, 11, 17 and 18.
  • the series-connected resistors 10 and 11 receive the sum of the voltage of a tachometer 12 and constant DC. voltage from a source 13.
  • a tachometer 19 is connected across resistors 17 and 18.
  • the tachometer 12 is mechanically coupled to the driving rollers 1 and its output therefore represents the linear speed of the unwound strip; the tachometer 19 is mechanically coupled to the reel shaft 2.
  • a constant torque shown as a dashed line parallel to the speed axis in FIGURE 3 can be achieved by causing the coil current (FIGURE 4) to increase from the value a adjusted at rest to the value b. To the value b of the coil-current corresponds the torquespeed characteristic of the brake represented by a full line in FIGURE 3.
  • a of coil-current there would be a lower curve (i.e. a curve having lower ordinates) which is not represented in FIGURE 1, and -for which the turning point is at the left-hand end of this dashed line parallel to the speed axis.
  • the zero point of FIGURE 4 is displaced relative to FIGURE 3 so as to be at the abscissa of FIG- URE 3 corresponding to the turning point.
  • the characteristic in accordance with which the adjustment of the coil current must take place can be determined point-by-point by graphic methods from the natural torque-speed characteristic of the electro-magnetic brake employed.
  • a slightly curved characteristic (represented by the line a to b in FIGURE 4) is obtained, but it is possible to approximate this curve with sufiicient accuracy by a straight line. The manner in which the straight-line characteristic is obtained will be explained later.
  • the characteristic in accordance with which the coil current must be varied can likewise be determined point-by-point by graphic methods from the natural torque-speed characteristic of the electro-magnetic brake employed. An almost linear path is also obtained for this part of the current characteristic.
  • the coil current of the induction brake must therefore first be made to increase in dependence on the strip speed and then downwards in dependence on the reel speed, in accordance with the angled characteristic of FIGURE 4.
  • This angled current characteristic is obtained by the differential connection of the two tachometers 12 and 19.
  • the series-connected tachometer 12 and DC. voltage source 13 apply a voltage across potentiometer 10 and resistor 11 and the tapped voltage corresponds to the characteristic 1 (FIGURE 4).
  • the DC. voltage is responsible for the initial value a of the coil current when the reel is at rest.
  • the tachometer 12 coupled to the driving rollers delivers a voltage which increases in proportion to the speed of the unwound strip and remains constant when full strip speed has been reached (characteristic 1, FIGURE 4).
  • the tachometer 19, which is coupled to the reel shaft, delivers a voltage which increases in proportion to the speed of the reel.
  • This voltage is applied across the series-connected resistor 17 and resistor 18 and the voltage tapped at the wiper of resistor 17 corresponds to the characteristic 2 of FIGURE 2.
  • the negative ends of the resistors 11 and 18 are connected together.
  • the difference between the two voltages tapped by the wipers of the resistors 10 and 17 is applied across the potentiometer 9 and controls the coil current in accordance with the angled current characteristic (FIGURE 4).
  • This desired current characteristic is thus obtained by the difference of the two characteristics 1 and 2 (FIG- URE 4
  • the initial point a (FIGURE 4) and the slope of the current characteristic are also dependent on the initial diameter of the winding material. This effect is taken into consideration by the resistors 10 and 17.
  • the fixed resistors 11 and 18 represent the smallest possible winding diameter, i.e. that of the reel mandrel or shaft.
  • FIGURE 5 shows an example of the varation of resistance required to compensate for acceleration forces in dependence on the reel diameter.
  • the characteristic first has a negative slope but as the winding diameter increases, this changes to a positive slope.
  • Such a characteristic is obtained when the inertial moment of the unwinding mandrel together with the mechanically coupled parts is sufliciently large, in relation to the inertial moment of the wound coil, not to be disregarded.
  • This characteristic can be approximated by giving the two mechanically coupled rotary resistors 7 and 8 a stepped winding such as to produce for each of them a resistance curve (shown in dashes in FIGURE 5) consisting of a number of linear portions of different slopes,
  • the resistor 26 is introduced because of mechanical friction; the frictional forces at the reel shaft have a braking action and the applied deceleration voltage value has therefore to be smaller than the acceleration voltage value.
  • the resistors 7, 8, and 17 are set to the initial diameter of the winding 0n reel 2 and then remain at this setting throughout the unwinding operation, unless for any reasons the unwinding is stopped before the strip is completely unwound. In such a case, these potentiometers would be reset to the new initial diameter.
  • the apparatus described above provides good compensation for the changing diameter of the would strip as unwinding proceeds. However, compensation to such a degree of accuracy may not in all cases be necessary and where this is so the simplified apparatus of FIGURE 2 may be used.
  • This apparatus produces a coil current/ speed characteristic of the kind shown in FIGURE 6. It will be seen that in this case, once the unwound strip has attained full speed the coil current remains constant, the approximately hyperbolic torque-speed characteristic of the brake automatically providing some compensation for the effect, on the strip tension, of the decreasing winding diameter. As in the first case, the speed of rotation of the pole wheel of the brake is such that with the reel 2 stationary, the turning point of the torque-speed characteristic (or at least the point of maximum torque) is reached.
  • FIGURE 2 the tachometer 19 of FIGURE 1 is omitted together with the potentiometer 17 and the resistor 18 and the potentiometer 9 is supplied with the voltage between the wiper of the potentiometer 10' and the negative end of the resistor 11.
  • the apparatus is in other respects similar to that of FIGURE 1. As a consequence of these changes, the voltage applied across potentiometer 9 varies only with the output of the tachometer 12, superimposed on the constant D.C. voltage from the source 13. This provides the angled current characteristic shown in FIGURE 6.
  • Apparatus including an unwinding device having a reel for the material to be unwound and draw rollers for drawing the material from the reel, an eddy-current brake coupled to the reel shaft, means for rotating the pole wheel of the brake in a direction opposite to the direction of rotation of reel shaft, a tachometer connected to the draw rollers, a DC. voltage source connected in series with the tachometer, and a control circuit applying to the coil of the eddy-current brake a current which varies with the sum of the tachometer voltage and the DC.
  • control circuit for the coil of the brake includes an adjustable resistance to be set in accordance with the intial diameter of the wound material on the reel, the adjustable resistance being connected to the constant DC voltage source through a reversing switch which is closed in one sense during acceleration and in the opposite sense during deceleration of the reel, the deceleration circuit including an additional resistor.
  • the said adjustable resistance comprises two resistors, both set in accordance with the initial diameter of the wound material, the two resistors being contoured to provide a non-linear resistance variation and having their wipers connected in mechanical opposition so that the sum of their resistances, plotted against the diameter of the wound material, first decreases in non-linear manner as the diameter is reduced and then increases, to provide the required acceleration characteristic.
  • An arrangement for maintaining substantially constant the tension in the wound material in an unwinding device including a reel for the material to be unwound and draw rollers for drawing the material from the reel, an eddy-current brake coupled with the unwinding shaft and having a torque speed characteristic which after reaching a maximum torque falls approximate-1y hyperbolically with increasing slip, a motor for driving the pole wheel of the brake in a directon opposite to that of the reel shaft, a tachometer connected to the draw rollers, a AC. voltage source connected in series with the tachometer, a plurality of resistors, and wipers therefor in which (a) the free ends of the DC. source and the tachometer connected in series are connected to the ends of a first one of said resistors which (b) is connected by one of its ends and by its 'wiper with both ends of a second resistor, and
  • each of the first and third resistors consist of two parts, one of them representing diameter of the core on which the material is wound and the other being adjustable in function of the initial diameter of the material wound on the core.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Controlling Rewinding, Feeding, Winding, Or Abnormalities Of Webs (AREA)
  • Tension Adjustment In Filamentary Materials (AREA)
US582291A 1965-09-29 1966-09-27 Unwinding apparatus Expired - Lifetime US3421710A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH1344765A CH440899A (de) 1965-09-29 1965-09-29 Verfahren und Anordnung zur Konstanthaltung der Zugspannung des Wickelgutes in einer Abwickeleinrichtung
CH1361465A CH445245A (de) 1965-09-29 1965-10-01 Verfahren zum Einhalten einer konstanten Zugspannung des Wickelgutes an einer Abwickeleinrichtung und Anordnung zur Ausführung des Verfahrens

Publications (1)

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US3421710A true US3421710A (en) 1969-01-14

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ID=25712326

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Application Number Title Priority Date Filing Date
US582291A Expired - Lifetime US3421710A (en) 1965-09-29 1966-09-27 Unwinding apparatus

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US (1) US3421710A (US07714131-20100511-C00038.png)
BE (1) BE687579A (US07714131-20100511-C00038.png)
CH (1) CH445245A (US07714131-20100511-C00038.png)
FR (1) FR1500420A (US07714131-20100511-C00038.png)
GB (1) GB1155874A (US07714131-20100511-C00038.png)
NL (1) NL154886B (US07714131-20100511-C00038.png)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4693049A (en) * 1982-05-04 1987-09-15 International Packaging Machines, Inc. Stretch wrapping machine
US5709350A (en) * 1996-02-14 1998-01-20 Davis; Joseph Louis Device for transferring fishing line
WO2006039426A1 (en) * 2004-09-29 2006-04-13 Goss International Corporation Control method for a static belt reel tension paster
CN103287897A (zh) * 2012-02-29 2013-09-11 湖南晟通科技集团有限公司 一种涂层机开收卷系统中的传感器惯性补偿方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3853282A (en) * 1972-12-06 1974-12-10 Beloit Corp Tensioning device
US3912145A (en) * 1974-03-04 1975-10-14 Butler Automatic Inc Web tension control system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB544925A (en) * 1940-10-29 1942-05-04 English Electric Co Ltd Improvements in driving means for reels on which material is coiled
US2469706A (en) * 1944-05-04 1949-05-10 Martin P Winther Electronic tension control apparatus
US2917252A (en) * 1958-04-25 1959-12-15 Eastman Kodak Co Tension control apparatus
US3049313A (en) * 1959-07-27 1962-08-14 Black Clawson Co Web tension control system
US3257086A (en) * 1963-08-02 1966-06-21 John W Drenning Tension equalizing control system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB544925A (en) * 1940-10-29 1942-05-04 English Electric Co Ltd Improvements in driving means for reels on which material is coiled
US2469706A (en) * 1944-05-04 1949-05-10 Martin P Winther Electronic tension control apparatus
US2917252A (en) * 1958-04-25 1959-12-15 Eastman Kodak Co Tension control apparatus
US3049313A (en) * 1959-07-27 1962-08-14 Black Clawson Co Web tension control system
US3257086A (en) * 1963-08-02 1966-06-21 John W Drenning Tension equalizing control system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4693049A (en) * 1982-05-04 1987-09-15 International Packaging Machines, Inc. Stretch wrapping machine
US5709350A (en) * 1996-02-14 1998-01-20 Davis; Joseph Louis Device for transferring fishing line
WO2006039426A1 (en) * 2004-09-29 2006-04-13 Goss International Corporation Control method for a static belt reel tension paster
CN103287897A (zh) * 2012-02-29 2013-09-11 湖南晟通科技集团有限公司 一种涂层机开收卷系统中的传感器惯性补偿方法
CN103287897B (zh) * 2012-02-29 2018-11-02 晟通科技集团有限公司 一种涂层机开收卷系统中的传感器惯性补偿方法

Also Published As

Publication number Publication date
CH445245A (de) 1967-10-15
BE687579A (US07714131-20100511-C00038.png) 1967-03-01
NL154886B (nl) 1977-10-17
GB1155874A (en) 1969-06-25
NL6613740A (US07714131-20100511-C00038.png) 1967-03-30
FR1500420A (fr) 1967-11-03

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