US3912184A

US3912184A - Control of yarn tensions

Info

Publication number: US3912184A
Application number: US398690A
Authority: US
Inventors: Karl Bous
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-19
Filing date: 1973-09-19
Publication date: 1975-10-14
Anticipated expiration: 1992-10-14
Also published as: GB1449492A; DE2245869A1

Abstract

A method and device for supplying yarn to yarn treating processes is provided in which the yarn supplied is placed under a desired tension. The device includes two spaced delivery rollers about which the yarn runs in several windings. Interposed the rollers are three braking surfaces disposed parallel to the roller axes. The yarn passing between the rollers passes alternately above and below such surfaces and in slidable contact therewith, the middle surface is movable relative to the surfaces disposed on either side thereof whereby a variable tension may be applied to the yarn engaged, depending upon the disposition thereof.

Description

[451 Oct. 14, 1975 CONTROL OF YARN TENSIONS [76] Inventor: Karl Bous, Sternstr. 74, 56

Wuppertal 2, Germany 22 Filed: Sept. 19, 1973 21 Appl. No.: 398,690

[30] Foreign Application Priority Data Sept. 19, 1972 Germany 2245869 [52] US. Cl 242/47.01; 66/132 R; 242/47.09 [51] Int. Cl. 8651-1 51/20 [58] Field of Search 2,658,367 11/1953 Shortland ..66/132 Primary ExaminerStanley N. Gilreath Attorney, Agent, or FirmNeuman, Williams, Anderson & Olson [5 7] ABSTRACT A method and device for supplying yarn to yarn treating processes is provided in which the yarn supplied is placed under a desired tension. The device includes two spaced delivery rollers about which the yarn runs in several windings. lnterposed the rollers are three braking surfaces disposed parallel to the roller axes. The yarn passing between the rollers passes alternately above and below such surfaces and in slidable contact therewith, the middle surface is movable relative to the surfaces disposed on either side thereof whereby a variable tension may be applied to the yarn engaged, depending upon the disposition thereof.

3 Claims, 5 Drawing Figures US. atem 0d. 14, 1975 Sheet 1 of 3 3912,18

US. atant 0a. 14, 1975 Sheet 2 of3 3,912,18

CONTROL OF YARN TENSIONS The invention relates to a method and a device for supplying and tensioning yarns during winding or other yarn treatment processes with an adjustable thread tension which remains constant throughout the winding step.

In yarn treatment, an adjustable but constant yarn tension is in most cases the prerequisite for a satisfactory output of the goods produced. However, since yarn tension is dependent on several factors, such as the speed of removal, the diameter and type of the outlet members, the constitution of the yarns and many other factors, before the actual thread brakes, so-called yarn supply systems, fournisseurs or yarn stores are often used, which partially eliminate tension differences which arise when removing the yarn and if necessary allow the yarn to be treated with a lower thread tension.

It is necessary to differentiate between supply systems with positive introduction of yarn, which are only used in certain cases, and the frequently-used, so-called slip supply systems. It is the purpose of supply systems with a positive introduction of yarn in particular to keep constant certain yarn sections between two or several supply systems, e.g. when producing continuous strips of yarn. Yarn storage devices are frequently used with such textile machines when the removal of yarn is often interrupted or takes place at various speeds, e. g. on knitting or weaving machines.

It is the main task of the slip-supply systems, which are usually used on winding machines, to reduce the tension differences arising when removing the yarn from the outlet member and e.g. to allow the winding or softer rollers. The requirement of reducing the yarn tension and partially compensating the thread tension can be fulfilled easily by slip-supply systems. However, in order to keep yarn tension exactly constant, thread brakes, advantageously compensatory thread brakes, are provided, which balance the tension differences up to a certain limit, but at the same time increase yarn tension again, which in many cases is undesirable.

It is the aim of the invention to lead the yarn to the corresponding device with an adjustable and, if necessary, very low thread tension and at the same time to keep constant thread tension during the entire operating process by means of only one controllable supply system. One embodiment enables the yarn to be introduced automatically into the supply system simultaneously, which is very important in the progressive automation of yarn treatment machines, since until now the yarn could only be guided through the supply rollers of the supply system by hand.

Further embodiments enable yarn tension to be controlled by the connected device and/or the introduction of yarn to be stopped for a shorter or longer time or to be quickened up to proceed at high speeds of removal and upon breakage of a thread to stop the supply system and/or the device working together with the supply system.

This is achieved in accordance with the invention in that the supply system, which consists of one supply roller and at least one rotating or stationary guide roller, or also of two driven supply rollers, is equipped with one or more braking levers which rest on all or some of the coils of the yarn which is being guided via the supply system and, according to the thread tension,

the one or more levers increase or reduce the size of the looping angle by means of braking elements provided and thus balance out tension differences, whereby the initial tension of the yarn can be regulated by the peripheral speed of the supply rollers and the pressure of the braking pins resting on the yarn coils and determining the looping angle, and it is compensated by feelers at the entry and/or exit of the yarn from the supply system by the braking lever and braking pins. On the other hand, the braking pins can be connected to the machine by means of braking levers and rods or other devices, the machine itself determining the required yarn tension and/or temporarily stopping the supply of yarn without having to stop the drive of the supply rollers.

Further features of the invention are described below with the aid of the accompanying drawings in which several preferred embodiments are illustrated in perspective or partially schematically. The features to be seen from the drawings can be used alone or in any combination in other embodiments of the invention.

FIG. 1 shows a perspective view of a supply system consisting of a driven supply roller, a guide roller and a braking lever;

FIG. 2 shows a perspective view of a supply system equipped with a compensatory lever and a yarn tension feeler;

FIG. 3 shows a front view of a supply system consisting of two driven supply rollers, braking elements and a compensatory lever;

FIG. 4 shows the supply system of FIG. 3 in plan view; and

FIG. 5 shows a supply system for compensating the yarn tension differences with braking and compensatory elements at the entry and exit of the supply system, in front elevational view.

In FIG. 1 is illustrated a perspective view of a supply system consisting of a driven roller, one or more guide rollers and a thread brake lever, which system itself compensates the yarn tension.

The yarn, coming from an outlet spool, a cop or a strand, is guided according .to the type of yarn and the desired reduction in yarn tension once or several times about a supply roller 2, which is driven in the direction of the curved arrow and about the guide rollers 3, which are rotatably mounted on a support pin 4 or can be fixed thereon, and the yarn is then led to a winding point which is not illustrated or to another device for further treatment of the yarn. The guide rollers 3 are advantageously provided with grooves 5 which determine the distances between the yarn windings on the supply system. The individual guide rollers can however also be replaced by a thread guide pin provided with grooves which guide the thread windings.

In many cases, however, it is more advantageous to use a smooth thread guide pin or a multi-pulley roller which is made to revolve by the yarn, whereby the distance between the yarn windings on the supply device can be adjusted by inclining the thread guide pin or the pulley roller towards the axis of the driven supply roller.

A brake lever 6 rests with its braking pin 7 on all or on one only of the yarn windings guided about the supply system, the pin 7 being made of a material of high surface hardness and which has a lower or higher coefficient of friction according to the type of yarn. The brake lever 6 with the optionally interchangeable braking pin 7 is secured to a lightly pivotable holder or mounting 10, together with weighting levers 8 and 9.

The function of the device of FIG. 1 is as follows: The yarn 1 which is guided e.g. four times about the supply system is removed from the outlet spool by the driven supply roller 2, whose peripheral speed, as usual with slip-supply systems, must be greater than the thread speed. The force of withdrawal of the yarn from the offwinding spool through the supply system is smaller or greater, depending upon the rate of revolution of the yarn about the supply system and the peripheral speed of the supply roller, and the yarn tension which is caused by the ball of threads or by other reasons is reduced to a greater or lesser extent, whereby at the same time the yarn tension differences arising during withdrawal are partially eliminated before winding of the yarn on to the takeup spool by the known tensionbalancing effect of the slip-supply system.

The tension-balancing effect of the slip-supply system is only slight, however, and for this reason the braking pin 7 of the brake lever 6 is placed on the yarn winding as they are guided about the supply system, aided by the weight of the counterbalanced braking weight 11 on the lever 8. Irrespective of the speed of withdrawal, the thread tension of the yarn being guided about the supply system and the pressure of the braking pin on the yarn windings 12, the yarn is looped around the braking pin with a smaller or greater looping angle, whereupon the thread tension in the yarn section 13 increases.

After the desired yarn tension has been set between the supply device and the winding point or the device for further treatment of the yarn by means of the counterbalance l1 and 14, i.e. the braking weights displaceably attached to the weighting levers 8 and 9, respectively, the yarn tension in the yarn section 13 remains constant independently of the tension differences between the off-winding member and the supply system, since when the yarn tension between the offwinding member and the supply system becomes greater or when the speed of withdrawal of the yarn becomes greater, e.g. through the winding point, the yarn tension of the yarn windings about the supply system also increases, less yarn is wound around the breaking pin and its braking effect on the yarn is reduced, so that the yarn tension in the yarn section 13 remains constant.

In the opposite case, when the withdrawal tension of the yarn from the off-winding member is smaller or when winding is at a lower speed, the thread tension of the individual yarn windings about the supply system also reduces, the braking pin engages deeper into the windings, its braking effect increases and the thread tension in the yarn section 13 increases to the adjusted value. If, in an extreme case, the connected device temporarily stops the withdrawal of yarn, the braking pin engages so deeply into the yarn windings that it completely eliminates operation of the supply roller.

If, however, a greater braking effect is required because of a low coefficient of friction of the yarn or of the braking elements, it is advantageous to arrange a further fixed braking pin 15 between the supply rollers and the movable braking pin, which pin 15 is to be attached such that when viewed from the direction of movement of the yarn it comes into contact under the yarn windings 12 closely before the movable braking pin. As soon as the movable braking pin presses down on the yarn coils e.g. when the yarn tension drops or when the withdrawal speed is reduced, the yarn windings loop around the fixed braking pin 15 also, and at the same time the looping angle of the yarn about the movable braking pin 7 becomes greater, so that there is a significantly greater braking effect on the yarn and the tension differences are balanced more quickly. There is an additional advantage, since the braking pin 15 at the same time prevents alteration of the looping angle of the yarn coils about the driven supply roller.

If, however, rotatably mounted guide rollers or multipulley rollers must be used, and the additional braking effect of the looping angle about the guide rollers cannot be dispensed with, a further braking pin 16 is to be provided between the movable braking pin and the rotatably mounted guide rollers, as illustrated in FIG. 1.

The combination of a movable braking pin with two counter-balances and two fixed braking pins, between which the yarn windings are pressed to a greater or lesser extent by the movable braking pin dependent on the yarn tension, can be applied to any section of the yarn windings being guided about the supply system. e.g. even on the lower yarn runs 17, since in this case the looping angles of the yarn windings about the supply roller and the guide rollers do not alter.

In certain cases, in order to avoid too great a yarn tension which is caused by the braking pins and to be able to guide the yarn to the winding point with very low yarn tension, the peripheral speed of the supply roller should be greater than with conventional slip-supply systems and it should also be possible to keep the pressure of the braking pin 7 on the yarn windings very low, e.g. by adjusting the counterbalance 14.

The supply system illustratedin perspective view in FIG. 2 is additionally equipped with a yarn tension feeler 18, about which the yarn 19 coming from the supply system moves at an angle to a winding point which is not illustrated or to another device for further treatment of the yarn.

The yarn tension feeler is a bar 18 connected on the journal 22 to the braking pin 23 by means of the compensatory lever 20 and the holder 21 which is positioned so as to be easily pivotable. The desired yarn tension is set e.g. by means ofa tension spring 25 interconnecting the lever 20 and a mounting member adjustably secured in an elongated slot 24, the spring 25 pulling the tension feeler 18 in the direction of the arrow A, opposite to the direction of yarn tension. When the yarn tension in the yarn section 19 becomes smaller, the yarn tension feeler 18 is moved by the effect of the tension spring 25 further in the direction A, and through the compensatory lever 20 and the holder 21, this movement is transferred to the braking pin 23, which presses into the yarn windings 26 to a greater extent, so that the looping angle of the yarn windings 26 about the braking pin 23 increases and the yarn tension in the yarn section 19 increases until the state of equilibrium has been reached again between the spring force and the yarn tension.

In the opposite case, when the yarn tension in the yarn section 19 becomes greater, the tension feeler 18 moves in the direction of the arrow B, the braking pin does not penetrate so far into the yarn windings 26 and the yarn tension between the supply system and the winding point reduces immediately to the value set. As already described in connection with FIG. 1, the device of FIG. 2 can also be equipped with further fixed braking pins and the force of the tension spring 25 can be replaced by weights, permanent magnets or centrallycontrolled electromagnets.

If, however, the yarn tension is to be controlled in dependence upon the treatment process, the yarn tension control device of the connected machine engages on the compensatory lever by means of a rod which is not illustrated and/or displaces the journal of the tension spring in the elongated slot 24 in the direction A or B. Should however the yarn tension-balancing effect of the tension feeler partially remain, the connected device should only displace the journal of the tension spring in the elongated slot 24.

FIG. 3 shows in front view and FIG. 4 in plan view a supply system consisting of two driven supply rollers, braking elements and a yarn tension compensatory lever.

The

supply rollers

27 and 28, between which are located the fixed braking pins or

braking surfaces

29 and 30, as well as the lever 32, which is pivotally mounted about the spindle 31, with the braking pin 33, are rotated in the direction of the arrow at a speed which is about 30% to 100% higher than the speed of withdrawal of the yarn from a supply device which is not illustrated.

On the lever 32 is also secured a tension spring 34, which by means of the lever presses the braking pin 33 between the braking surfaces 29 and 30, whereby the tensile force of the spring 34 can be adjusted by moving the knob 35 in the direction C or D. After lifting the lever 32, on which is secured the braking pin, the yarn 36, which is to be wound is guided once or several times about the supply rollers, so that the yarn comes to rest between the braking surfaces and the braking pin, whereupon it is guided by means of the thread guide roller 37 on the compensatory lever 38, which is also secured to the lever 32, at an angle through the thread guide roller to the next winding point.

When using the device of FIGS. 3 and 4, according to the tension of the yarn 36, being removed from a spool, a cop or a strand and depending upon the peripheral speed of the supply rollers and the winding speed, the yarn tension of the yarn windings about the supply system will be larger or smaller, and the braking pin will press the yarn coils to a greater or lesser extent between the braking surfaces through the effect of the tension spring.

After setting the desired yarn tension between the supply system and the winding point by moving the knob 35, by simultaneous supplying and braking of the yarn coming from the supply system, there is equilibrium between the spring tensile force and the yarn tension in the section 42. Due to yarn tension differences of the yarn being led to the supply system and/or due to yarn removal speed differences at the winding point, the thread guide roller 37 moves in the direction E or F. This movement is transferred by the compensatory lever 38 to the braking parts so that the yarn tension in the section 42 remains constant.

Undesirable oscillatory movements of the compensatory lever which are in quick succession, can be avoided by a damping device, e.g. an eddy-currentvibration damper, which consists of an aluminium or coppper segment attached to the spindle 31, and the permanent magnet 41. A scale 55 on the circular part 54 of the segment 40 allows the adjusted or existing yarn tension to be read simultaneously.

On the spindle 31 firmly connected to the lever 32, further auxiliary levers which are not illustrated can be attached, which also undergo pivoting movement about the spindle, and if the given yarn tension value drops or increases, they disconnect the winding point or the connected device for further treatment of the yarn and- /or the compensatory supply system, e.g. by means of micro-switches. With the same or other means, which are actuated by the movement of the compensatory lever or of the segment 40, if the thread breaks, and the braking pin reaches the point G through spring force or if a yarn coil is formed on the supply rollers and presses the braking pin in the direction H, the supply and/or winding device is disconnected.

The spacing of the yarn windings or coils on the supply system can be determined by incling the two supply rollers relative to one another by means of the yarn guide pins 39 or a yarn guide comb.

In FIG. 5 a supply system in front view for compensating the yarn tension with braking and compensatory elements at the entry and exit of the supply system.

The function of this device is essentially the same as that of the supply system described in relation to FIG. 2, but additionally it allows the yarn tension oscillations to be sensed, which arise during withdrawal of the yarn 57 from the cop 58, before it enters the supply system through the thread guide roller 59 on the compensatory lever 60. The compensatory lever 60, the counterbalance lever 61 with the adjustable weight 62 and the braking lever 63 with the braking pin 64 are secured to the holder 66 which is mounted on the journal 65 for easy pivotal movement.

The braking pin 64 rests on the yarn section 67 of the windings of the supply system, which consists of a supply roller 68 driven in the direction of the curved arrow and the guide roller 69, and according to the yarn tension in the yarn section 67, it presses the yarn coils to greater or lesser extent, whereby the looping angle of the yarn about the braking pin and thus also its effect on the yarn coming from the supply system is increased or reduced.

Similarly to the yarn tension compensatory device, whose breaking effect is determined by the yarn tension between the yarn removal member and the supply system, a further mirror-image device is attached on the journal 65, consisting of the holder 70, the thread guide roller 71, a compensatory lever 72 and a counterbalance lever 75 with its interchangeable braking pin 76.

However, the looping angle of the braking pin 76 through the yarn section 77 of the windings about the supply system is determined by the yarn tension in the section 78, between the supply system and the device for the further treatment of yarn.

The device shown in FIG. 5 can be supplemented with further braking pins to increase the yarn tension compensation, as described in connection with FIG. 2, and the counterbalances can be supplemented by springs, permanent or electro magnets, e.g. the braking pin 64 can be controlled by the yarn tension before or after the supply system and the braking pin 76 by the yarn tension-control device of the connected device.

Because the parts or holders which are moved by the compensatory levers in FIGS. 2, 3 and 5 are equipped with levers on which are mounted rollers which are easily rotatable, the effect of friction between the yarn and the sensing levers can be dispensed with, so that the compensatory effect of the devices is further improved.

In particular cases, the braking devices illustrated in FIGS. 3 and 4 can be moved in an oscillatory manner in order to prevent the yarn from cutting into the supply rollers or the braking parts.

The segment 40 in FIGS. 3 and 4 can be equipped with a pointer or a marking instead of a scale, which indicates the yarn tension on a scale attached to the housing of the device.

I claim:

1. In a device for delivering yarn under desired, substantially constant tension to a zone of yarn use, the combination comprising two spaced delivery rollers about which such yarn runs in several windings, at least one of said delivery rollers being a drive roller, three braking surfaces disposed between said rollers and arranged parallel to each other and to the delivery rollers, said yarn passing alternately above and below said three surfaces in constant slidable contact therewith in the normal yarn delivering operation, the two outer braking surfaces being fixedly positioned; the middle braking surface disposed between said outer surfaces being movable relative thereto; said movable middle surface effecting various pressures on the yarn engaged thereby; said pressures being dependent upon said movable middle surface disposition relative to said outer surfaces; means urging said movable braking surface in the direction of and between said fixed braking surfaces so as to increase the looping angle of the engaged yarn about said movable braking surface and increase the tension of said yarn caused by said movable braking surface; increased tension in the yarn in the zone of use forcing said movable braking surface to withdraw from between the fixed braking surfaces whereby the looping angle of the engaged yarn about said movable braking surface is decreased and the tension in said yarn caused by said movable braking surface is decreased; said middle braking surface comprising a brake pin, a pivotally movable lever fastened to said brake pin and movable about a pivot axis disposed parallel to said pin, an adjustable spring engaging said lever, said spring effecting the movable brake pin contact pressure with such yarn, a compensation arm mounted on said lever having a thread guide roll arranged on its distal end, which roll is encircled in part by yarn emerging from the device in such a way that the yarn tension counteracts the tension in said springengaging lever.

2. The device of claim 1 in which a pivotally movable segment of aluminum or copper is mounted on said lever and moves relative to a permanent magnet so as to effect eddy-current vibration damping of said lever and the movable brake pin mounted thereon.

3. The device of claim 1 in which a scale is connected to said movable brake pin whereby the yarn tension corresponding to said brake pin angular disposition may be read at a glance.

Claims

1. In a device for delivering yarn under desired, substantially constant tension to a zone of yarn use, the combination comprising two spaced delivery rollers about which such yarn runs in several windings, at least one of said delivery rollers being a drive roller, three braking surfaces disposed between said rollers and arranged parallel to each other and to the delivery rollers, said yarn passing alternately above and below said three surfaces in constant slidable contact therewith in the normal yarn delivering operation, the two outer braking surfaces being fixedly positioned; the middle braking surface disposed between said outer surfaces being movable relative thereto; said movable middle surface effecting various pressures on the yarn engaged thereby; said pressures being dependent upon said movable middle surface disposition relative to said outer surfaces; means urging said movable braking surface in the direction of and between said fixed braking surfaces so as to increase the looping angle of the engaged yarn about said movable braking surface and increase the tension of said yarn caused by said movable braking surface; increased tension in the yarn in the zone of use forcing said movable braking surface to withdraw from between the fixed braking surfaces whereby the looping angle of the engaged yarn about said movable braking surface is decreased and the tension in said yarn caused by said movable braking surface is decreased; said middle braking surface comprising a brake pin, a pivotally movable lever fastened to said brake pin and movable about a pivot axis disposed parallel to said pin, an adjustable spring engaging said lever, said spring effecting the movable brake pin contact pressure with such yarn, a compensation arm mounted on said leveR having a thread guide roll arranged on its distal end, which roll is encircled in part by yarn emerging from the device in such a way that the yarn tension counteracts the tension in said spring-engaging lever.