US2688111A - Winding tension apparatus - Google Patents

Description

Aug. v31, 1954 M. G. JONES 2,688,111

WINDING TENSION APPARATUS Filed Feb. 5, 1952 Q INVENTOR. MICHAEL GRAVATT JONEJS E @1M/29M Arron/v Patented Aug. 31, 1954 UNITED STATES PATENT OFFICE WINDING TENSION APPARATUS Michael Gravatt Jones, Fredericksburg, Va., assignor to American Viscose Corporation, Philadelphia, Pa., a corporation of Delaware Application February 5. 1952, Serial No. 269,926

(Cl. S18- 6) 3 Claims.

proper amount of tension often causes variousI undesirable effects such as deformation of the storage package. It has been found that package deformation may be minimized and that best winding results may be obtained by maintaining a constant tension upon the material during the winding operation or by slightly diminishing the same continuously and progressively as the material package builds outwardly from its core.

Hereinbefore various control systems have been devised which purport to maintain a constant Winding tension as the material package builds up on the storage device. Some of these systems merely strive to maintain the angular Velocity of the Winding motor constant but such systems have been found unsatisfactory since as the diameter of the material package increases the peripheral velocity thereof and the material winding tension likewise simultaneously increase. Other control systems have been suggested wherein the armature current applied to an electrical winding motor is maintained constant. It is reasoned that, since the power output of the motor is proportional to the armature current supplied thereto, a constant power output and winding tension may be obtained by maintaining a constant motor armature current. One such electrical control system, of which the present invention is an improvement, includes a generator whose armature output circuit supplies energizing current to the material winding motor and whose -output voltage is controlled by regulating the generator iield excitation in accordance with the voltage drop across a series resistor in the generator output circuit. Thus, in the operation of this system, as the diameter of the material package increases, the winding motor torque increases, greater current tends to flow in the generator output circuit, a greater voltage -drop across the series resistor is produced, more lines of force are created which oppose the regular energizing eld of the generator and a smaller resultant generator voltage tends to maintain a constant armature current thereby reducing the speed of the motor and purportedly maintaining constant winding tension in the lamentary material.

It has been found, however, that increased winding tension is produced in this type of control system particularly when relatively heavy packages, such as rolls of cellophane, paper, etc., and warp beams are being wound. As the material package builds outwardly from its core during the winding operation and the `speed (R. P. M.) oi the winding motor is decreased to maintain the peripheral speed of the package substantially constant, frictional losses in thev winding motor and the take-up roll also decrease. Thus, although the torque developed by the motor may be theoretically maintained constant by controlling the magnitude or" its armature current, less frictional forces are present to oppose the same and greater rotational energy is made available to produce increased tension in the material being wound, In the present system, however, the torque developed by the motor must be somewhat increased simultaneously with decrease in rotational speed to achieve a condition of constant web feed and constant web tension.

It is a principal obj ect of the present invention yto provide an electrical control system for winding apparatus wherein the tension developed in a material which is being wound upon a core may be conveniently and accurately maintained constant or controlled.

The accompanying drawing discloses a circuit diagram of Winding control apparatus which is operative in accordance with a preferred embodiment of the present invention. As illustrated therein a material 3, such as a diam-ent yarn, a warp sheet, and a film or sheet, such as cellophane progresses at a constant rate from a suitable source not shown on the drawing about the liquid treating or drying drums 2, d 6 tc the take-up device 3 comprising a winding core 8a. The core of the take-up device d is mechanically connected by the shaft d to the motor Mi which drives the device d and determines ie degree of tension applied to the material as it is wound thereon.

The three-phase motor M2 is energized from a suitable source not shown on the drawing through the control switch il. Shaft l? which is driven by motor M2 is mechanically coupled to the armature of the exciter E, the control genera-tor CG, and the main generator MG.

The exciter E provides an independent direct current source for the control system and includes a shunt field winding i9 and a series field winding 2li. The variable resistor 2| is provided in the shunt field winding circuit to permit control of the exciter generator at its output terminals 22 and 23.

The armature of motor Ml is energized by the main generator MG through a circuit which may be traced from the generator terminal IIJ, through conductor l l, resistor l2, conductor i3, motor Mi, conductor lli, contact l5, to the other generator terminal l5. The separately excited field winding 24 of motor MI is energized by a circuit which is connected to the output terminals 22 and 23 of the exciter E and includes the variable erator is energized by four other field windings which may be called the anti-hunt eld, the pattern eld, the diierential field and the cumulative eld. The anti-hunt eld winding 33 is connected in series with the variable resistor 32 across the output terminals 2l and 32 of the control generator and tends to stabilize its voltage output.

The pattern eld winding 35 of the control generator is provided with a pair of parallel energizing circuits. By one circuit it is energized by the output Voltage of the exciter generator E which may be 'traced from the terminal 23, through conductor d, variable resistor l5, relay contact di, the pattern iield winding, conductor 42, relay contact 13, conductor M to exciter terminal 22. By the other circuit the pattern iield winding of the control generator is energized by the output voltage of the main generator MG from the terminal i6 through conductor 45, variable resistor li, relay contact lil, the pattern field winding, conductor d8, relay contact de to the opposite generator terminal i5.

The differential field winding Eli of the control generator and the series variable resistor i are energized by the voltage across the potentiometer i2 which therefore is proportional to the magnitude of armature current which is supplied to the motor Mi as will be more fully described hereinafter.

Cumulative control generator field winding 52 is also provided with a pair of parallel energizing circuits. By one of these circuits it is energized by the output voltage of the pilot generator PG which is coupled by the shaft 35 to the drying drum 6. This circuit may be traced from terminal 3l of the pilot generator through conductor 38, relay contact 53, conductor 6G, the cumulative winding, conductors 59 and 82, relay contact 39, Conductor 5d, variable resistor l5, to the opposite pilot generator terminal 55. By the other circuit the cumulative field Winding of the control generator circuit is energized by the armature voltage of motor Mi. This circuit may be traced Lto from the armature terminal 55 of the motor through conductors id and 5l, relay contact 58, conductor 52, the cumulative winding, conductor Si?, relay contact 62, conductor t3, potentiometer Ed to the opposite armature terminal motor 55.

The various relay contacts mentioned hereinbefore are controlled by their respective relays which may be selectively energized by the exciter direct current source when their manually operable switches are closed. Thus, the main relay M may be energized when the manually operable switch 66 is closed and its associated contact l5 may be thereby closed to apply the output voltage of the main generator MG to the motor Ml.

ln a similar manner the speed relay S may be energized by the exciter E when contact B9 is closed and when its associated manually operable switch @l is closed. Upon its energization its normally open back contacts fil, d5, 39 and 53 all close and the speed of the motor ME may be synchronized with the rate of travel of the material 3 as will be more fully explained hereinafter.

When relay T is energized by a circuit `which extends from the terminals of exciter E thereto through the manual switch 68 and bacl: contact l of relay S the control generator pattern field is connected to the terminals of the exciter E. Relay Ti which is effectively in parallel with relay T may be energized when its manually operable switch il is depressed thereby placing the cumulative winding of the control generator across the armature of the motor Ml through contacts 58 and 62.

It is to be noted that contact S9 of relay T and contact 'E0 of relay S provide an interlocking means whereby neither of these relays can be energized while the other is energized.

In describing the operation of the winding control system of the present invention it will be first assumed that it is desired to wrap the material about an empty reel or take-up device 3. It has been found that when the peripheral speed of the take-up device 8 is made to correspond to the rate at which the material is fed thereto, the wrapping operation is greatly simplified. To accomplish this the operator closes manual switch tl to energize the speed relay S through the normally closed back contact B9 of relay T. Closure of its contacts lll, LlQ, 39 and 53 places the control generator pattern eld 35 across the output terminal of the main generator MG and the control generator cumulative field winding 52 across the output terminals of the pilot generator PG thereby providing an additional eld excitation source for the control generator. In this way by suitable adjustment of the variable resistor '16 in the cumulative eld circuit, the output voltages of the control generator and the main generator and the speed of motor Ml may be properly built up so as to facilitate the lacing operation. This may Aoccur should the web break, in which event the apparatus is laced up at speed.

Once the material has been properly wrapped upon thetake-up device 8, it is desirable to thereiafter control the speed of motor Ml such that as the package builds up and as the peripheral velocity tends to increase the tension is prevented from likewise increasing. To accomplish this the manually operable switch 5l in the speed relay energizing circuit is opened and the manually operable switches 53 and 'il are depressed to energize the associated relays T and Tl. Closure of contacts di and t3 or relay T places the pattern iield winding of the control generator across the output terminals of the exciter E and closure of contacts 58 and 52 of relay Ti places the control generator cumulative eld winding across the armature terminals of motor Mi.

With the field circuit of the control generator energized in this manner, the speed of motor MI may be controlled such that either a Constant or a drooping tension characteristic may be obtained. Thus since the diierential eld 5I] opf poses the eld created by the pattern Iield 35, increases in armature current applied to motor Ml increase the voltage drop across the series resistor I2 and the current through the differential field thereby diminishes still further the resultant control generator field and consequently the output voltage of main generator G.

As stated hereinbefore, however, as the rotational speed of the motor Ml decreases with the build-up of the package, reduced frictional losses do not aflect the magnitude of the motor armature current and therefore the tension improperly increases although the armature current of the motor and its developed power are maintained constant. For this reason the cumulative eld winding 52 has been provided in the present system to further affect the ultimate speed of motor Ml. The strength of the cumulative iield is therefore adjusted such that it aids the control generator pattern field. As the diameter of the package increases and the rotational velocity of the motor is decreased, as hereinbefore discussed, less back electromotive force is generated by the motor MI, less voltage is available to energize the cumulative field to aid the pattern field and therefore the output of the main generator MG and the rotational speed of the motor are properly further decreased so that the peripheral speed of the motor and take-up roll are maintained substantially constant.

The series field winding 3l of the control generator is adapted to amplify changes produced therein by the differential eld. The series variable resistor 29 in the control generator operates on the straight line portion of its saturation curve and thereby provides a linear amplication characteristic. The anti-hunt eld which is connected across the output terminals of the control generator CG is provided merely to dampen the oscillatory tendency of the control system.

It is to be noted that the present novel and improved control system provides a means whereby the actual tension produced may be accurately maintained constant or, if desired, may be controlled to diminish slightly as the package builds up.

Although the preferred embodiment of the present invention has been disclosed in connection with Winding materials such as yarns, sheets or iilms, it is to be understood that the system may be employed for winding any material upon a storage device without departing from the spirit or scope of the invention.

While preferred embodiments of the invention have been disclosed, the description is intended to be illustrative only, and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as delined by the appended claims.

I claim:

1. A control system for driving a web take-up roll under conditions of constant peripheral speed and constant web tension as the roll builds up, comprising a take-up roll, a motor for driving said take-up roll, a main generator for supplying current to the armature of said motor, a field winding for said generator, a control generator for energizing said main generator iield winding, a direct driving connection between the control generator and the main generator, a series field winding for the control generator, a shunt lield winding for the control generator, a differential eld winding for the control generator, a pattern field winding for the control generator, a cumulative field winding for the control generator, a

source of substantially constant voltage direct current, a pilot generator, a constant speed driving connection for the pilot generator, a circuit for connecting the pattern field across the constant voltage direct current supply, a circuit for connecting the pattern eld across the armature of the main generator, means including a relay for selectively connecting and disconnecting said circuits to the pattern eld, a circuit for connecting the cumulative field to the pilot generator, a circuit for connecting the cumulative field across the armature of the motor, and means including a relay for selectively connecting and disconnecting said last-named circuits to the cumulative field.

2. A control system for driving a web take-up roll under conditions of constant peripheral speed and constant `web tension as the roll builds up, comprising a take-up roll, a motor for driving said take-up roll, a main generator for supplying current to the armature of said motor, a eld Winding for said generator, a control generator for energizing said main generator eld winding, a direct driving connection between the control generator and the main generator, a series field Winding for the control generator, a shunt field winding for the control generator, a dierential field winding for the control generator, a pattern neld winding for the control generator, a cumulative field winding for the control generator, a source of substantially constant voltage direct current, a pilot generator, a constant speed driving connection for the pilot generator, a circuit for connecting the pattern eld across the constant voltage direct current supply, a circuit for connecting the pattern eld across the armature of the main generator, relay means for selectively connecting and disconnecting said circuits to the pattern field, a circuit for connecting the cumulative neld to the pilot generator, a circuit for connecting the cumulative neld across the armature of the motor, means including a variable potentiometer in the circuit connecting the cumulative eld across the armature of the motor whereby the strength of the cumulative eld is adjustable to oppose the differential eld, and relay means for selectively connecting and disconnecting said last-named circuits to the cumulative eld.

3. A control system for driving a web take-up roll under conditions of constant peripheral speed and constant web tension as the roll builds up, comprising a take-up roll, a motor for driving said take-up roll, a main generator for supplying current to the armature of said motor, a field winding for said generator, a control generator for energizing said main generator neld Winding, a direct driving connection between the control generator and the main generator, a series field winding for the control generator, a shunt field winding for the control generator, a diflerential field winding for the control generator, a pattern field winding for the control generator, a cumulative field winding for the control generator, a source of substantially constant voltage direct current, a pilot generator, a constant speed driving connection for the pilot generator, ya circuit for connecting the pattern ield across the constant voltage direct current supply, a circuit for connecting the pattern iield across the armature of the main generator, relay means for selectively connecting and disconnecting said circuits to the pattern eld, a circuit for connecting the cumulative field to the pilot generator, a circuit for connecting the cumulative References Cited in the le of this patent UNITED STATES PATENTS Number Name Date Evans Apr. 21, 1931 Michel Dec. 26, 1944 King et a1 June 6, 1950 Allbert et al. Sept. 19, 1950 Winchester Mar. 25, 1952

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