BUNDLE WITHDRAWN FROM A MASS OF COMPACTED YARN

This invention relates to an apparatus and method for controlling the tension on a yarn withdrawn as a yarn bundle from a mass of compacted ya¬ rn within a confined space and for maintaining an end portion of the com¬ pacted yarn mass within the confined space.

In the production of textured yarns from synthetic polymeric materials with a pneumatic bulking apparatus , a compacted mass of yarn or yarn plug is formed within a confined space. After the yarn mass accumulates within the confined space and after the yarn is heat-set, the yarn is removed fr¬ om the confined space and is taken off in the form of a yarn bundle. U . S . Patents 3, 983, 610 and 4, 095, 317 are directed, respectively, to a pneumatic apparatus and process for effecting the production of textured yarns within a confined space.

It has been proposed in accordance with U. S . Patent No. 3, 958, 734 to provide a method and apparatus for sensing the position of the compacted yarn mass within the confined space and for generating signals to control the speed of withdrawing or taking-up the yarn bundle from the compacted yarn mass and to control the inventory of the yarn mass within the confined sp¬ ace. In order to effect these controls , it is necessary to provide means for sensing the position of the yarn mass within the confined space and for reg¬ ulating the speed of the take-up unit that withdraws the yarn from the con¬ fined space based on the sensed position of the yarn mass .

It will be recognized that, heretofore, there have been many devices for regulating the tension applied to a yarn during yarn winding or yarn handling operations , e. g. U . S . Patent Nos . 143, 268; 988, 444; 2, 23, 211 and 2, 462, 043. Of these patents , that to Vanselow (U . S . 2, 423, 211) is of int¬ erest in that this patent discloses a knitting aid device that has a finger sleeve for receiving a spiral turn of yarn _. and a spring-operated means for applying tension to the yarn. This device is worn on the index finger of the operator and requires a spring operated plunger for applying tension to the yarn .

It is an object of the present invention to provide an apparatus and method for varying the tension on a yarn bundle being withdrawn from a compacted yarn mass introduced into a confined space with a variable input so that the yarn bundle can be withdrawn from the yarn mass by a const¬ ant speed take-up device.

It is a further object of the present invention to provide an apparatus and method that also control the inventory of the compacted yarn mass

within the confined space without requiring means for sensing the position of the compacted yarn mass within the confined space or means for contro¬ lling the withdrawal of the yarn based on this sensed position.

Advantageously, this invention contemplates an apparatus for contro¬ lling the tension on yarn withdrawn from a mass of compacted yarn within a confined space which comprises a yarn guide means having a tubular wall portion defining a confined space for guiding and for accumulating a com¬ pacted mass of yarn, an inlet opening for entry of the compacted mass of yarn into one end of the confined space, and an outlet opening for allowing withdrawal of the yarn in the form of a yarn bundle from the confined spac the outlet opening being an elongated slot provided in the tubular wall por tion of the yarn guide means. This slot has such a preselected configur¬ ation that the slot acts as a means for varying the tension applied to the yarn as the yarn mass moves from one end of the confined space to the ot¬ her end. More particularly, the yarn guide means of the present invention is a tubular element or member that has a tubular, preferably cylindrical wall defining the confined space and that has a slot in the cylindrical wall that extends along the length of the confined space, preferably from one e to a point adjacent to the other end.

In one embodiment of the apparatus, the slot is arranged in the cylin¬ drical wall to extend parallel to the longitudinal axis of the tubular element and has a width that increases continuously from one end to the other end order to decrease the amount of tension applied to the yarn along the lengt of the slot. *

In another embodiment of the invention, the slot in the cylindrical wall is -arranged to extend about the axis of the tubular element and form a heli cal passage for the yarn being withdrawn from the confined space. The sl may have a width that increases or remains constant from one end to the ot her end. This helical arrangement of the slot causes the yarn bundle with drawn from the confined space through the slot to wrap around an outside portion of the cylindrical wall of the tubular element, with the extent o- r- apping of the yarn about the cylindrical wall causing the tension applied to the yarn bundle to vary,L.e, the tension increases as the wrapping increas

In yet another embodiment of the invention, the tubular element has a cylindrical wall which is provided with an elongated slot having one part or portion that is in the form of a helix and another part or portion that ex¬ tends linearly parallel to the axis of the tubular element, with the width of

the slot remaining constant or continuously increasing from one end to the other end. -

In accordance with this invention, the yarn is pulled as a yarn bundle from the end of the compacted yarn mass or yarn plug in the confined space at an angle to the longitudinal axis of the tubular element. The cylindrical wall portion defining and surrounding the elongated slot or passage formed in the cylindrical wall of the tubular element serves to retain the remaining portion of the yarn mass within the confined space as the yarn bundle is formed. Moreover, the tension applied to the yarn bundle" withdrawn from the confined space determines the rate of removal of the yarn by varying the density and configuration of the yarn bundle. For example, when the yarn bundle is pulled from the compacted yarn mass under a high tension, the filaments forming the yarn bundle are stretched out to form a relatively dense yarn. Under a low tension the filaments forming the yarn bundle re¬ main in a crimped or bulked position to form a bulky yarn . Consequently, the amount of yarn removed from the compacted mass of yarn under high tension is less than the amount of yarn removed under low tension .

It will be understood that the inventory or amount of the compacted ya¬ rn mass retained in the confined space is, therefore, controlled by varying the tension applied to the yarn bundle.

Since the configuration of the elongated slot formed in the cylindrical wall portion of the tubular element is predetermined to apply a greater ten¬ sion at one end of the tubular element than at the other, the position of the end of the compacted yarn mass within the tubular element, that is within the confined space, serves to control the tension applied to the yarn bundle as the' yarn is being removed. The tension, in turn, controls the rate of yarn removal ^' or withdrawal from the confined _. .space. It will be appreciated that by appropriate selection of the configuration of the elongated slot, the dimensions of the tubular element as well as the winding or take-off rate of the yarn, the position of the yarn mass , particularly the end portion of the yarn mass, can be regulated to be retained within the confined space even though the input or delivery rate of the yarn mass to the yarn guide means is varied. This self-adjusting operation of the apparatus of the present invention is particu¬ larly effective for use with a constant yarn take-up device, such as a godet or winder, in that changes in the input or delivery of the compacted yarn mass to the confined space, that is into the tubular element, are compensated for or regulated automatically. That is, a change in the position for the end

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of compacted mass within the confined space will bring about a change in t tension applied to the yarn bundle and the rate of yarn removal.

Operation of the apparatus of this invention is as follows: a firm, ro¬ und-shaped yarn plug or compacted yarn mass is formed by a yarn textur¬ izing device such as disclosed in U . S . Patent No. 3, 983, 610 and is pushed by a pneumatic fluid through a conduit into the apparatus of the present invention. The yarn plug is introduced or delivered into the confined spa defined by the tubular element at the opening at the front end of the tubu element. At this time the yarn plug is moving at a speed of about 17200th of the yarn speed into the yarn texturizing device, that is at a speed of 2 to 15 meters per minute. Although the yarn plug is being formed by intro ducing yarn into the yarn texturizing device at a substantially constant ra there is a normal variation in the rate of plug build-up and, consequently, there is a variation in the input of the yarn plug into the confined space. The yarn plug enters the front open end of the tubular element and may exit from a rear open end of the tubular element. During start-up of the device, the end of the yarn is normally withdrawn from the yarn plug thr¬ ough the side of the tubular element via a portion of the elongated slot ad¬ jacent to the rear end of the tubular element. This r-ear end portion of th slot is usually provided with a width which will apply the lowest amount of tension to the yarn as it is being withdrawn from the yarn plug, e. g. from 5 to 10 grams. In one embodiment wherein the slot is entirely linear, the slot tapers to a width which is smaller near the inlet end of the tubular ele ment so that the amount of yarn withdrawn via the slot is reduced by caus ing an increase in the tension applied to the yarn bundle, as the end of th yarn plug moves back to the front of the tubular element.

In another embodiment of the invention wherein a spiral or helical elon gated slot is provided in the tubular element defining the yarn guide means the yarn bundle is initially pulled outwardly from the side at the rear end of the tubular element and because of the helical configuration of the slot, the yarn bundle is caused to wrap immediately about the outside portion of the tubular element when the end of the plug or confined compacted yarn mass moves toward the forward end of the tubular element. Accordingly, there is an immediate increase in the tension applied to the yarn bundle. In the embodiment of the invention wherein the tubular element is provided wi th an elongated slot that has one portion that is a helical configuration and another portion that is linear and parallel to the longitudinal axis of the

tubular element, the yarn bundle initially is pulled out from the side of the confined space at the rear end of the element through the linear portion of the slot. This arrangement allows the operator to stringup the apparatus and begin the take-up of the yarn at the lowest possible tension. There is no tension increase until the yarn plug moves back upstream toward the ^' fr÷ ont end of the element and the yarn bundle is pulled through the helical po¬ rtion of the slot and is caused to wrap about the outside of the tubular ele¬ ment.

In all embodiments, the change in position of the plug from the rear or downstream end to the front or upstream end of the tubular element causes an increase in the tension of the yarn bundle as it is being removed from the confined space and, consequently, reduces the amount of yarn being re¬ moved. The reduction in the rate of yarn removal then causes the end of the yarn plug to move forward in the tubular element and seek a position therein wherein the rate of input of the yarn plug is equal to the rate of yarn withdrawal as a yarn bundle. It will be appreciated that the apparatus of this invention enables ah operator of a texturizing apparatus to vary the yarn input and/or the constant take-up over a relatively large range by us¬ ing the same or different configuration of the elongated slot in a tubular el¬ ement of the same or different length.

The apparatus and method of this invention will be further understood from the following detailed description and with reference to the accompany¬ ing drawings , wherein:

Figure 1 is a side view showing the apparatus for controlling the ten¬ sion on a yarn bundle withdrawn from a compacted yarn plug within a con¬ fined space and for maint-aning an end portion of the yarn plug within the confined space used in conjunction with a yarn plug producing device and a yarn take-up device which are schematically illustrated;

Figure 2 is an end view of the apparatus for controlling the tension sh¬ own in Figure 1;

Figure 3 is a side view of another embodiment of the apparatus of the present invention wherein the tubular element forming the yarn guide means is provided with an elongated slot having a helical section and a linear sec¬ tion arranged in the tubular element with the slot having a constant width from one end to the other;

Figure 4 shows yet another embodiment of the tubular element wherein the slot arranged in a helical configuration has a width which increases from one end to the other;

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Figure 5 is a side view of the tubular element shown in Figure 3 with a plug being shown in phantom view within a portion of the confined space defined by the tubular element and a yarn bundle being withdrawn via the elongated slot formed within the tubular element;

Figure 6 is a perspective view of the arrangement of a plug forming device, a yarn take-up godet and a tubular element in accordance with the present invention, the tubular element having an elongated slot of a con¬ stant width with one portion of the slot arranged in a helix and another po rtion arranged linearly parallel to the longitudinal axis, with a wrap of yar formed thereon; and

Figure 7 is an end view of the tubular element and godet shown in Fi¬ gure 6 on a smaller scale,

In Figure 1 reference numeral 1 generally designates the apparatus of the present invention for controlling the tension on a yarn bundle withdraw from a mass of compacted yarn, that is a yarn plug, within a confined sp¬ ace. This apparatus includes a yarn guide means comprising a tubular ele¬ ment 2 having two open ends 3 and 4, respectively . End 3 defines an inle opening for delivery or entry of a compacted yarn mass in the form of a plug 5. This compacted yarn mass is formed by a yarn plug-producing de¬ vice schematically shown in the drawing and designated by reference num¬ eral 6. The yarn plug is introduced into the opening at end 3 through a conduit 7 which is secured to the end 3 of the tubular element,

A slot designated by reference numeral 8 extends along a major pro¬ portion of the length of the tubular member and defines an outlet opening for withdrawing the yarn bundle 9 by a yarn take-up device 10 which in¬ cludes a spindle or the like element for winding the yarn bundle into a yar package. As shown the yarn bundle is pulled through slot 8 from the yarn plug at an angle of about 90° with respect to the longitudinal axis of the tubular element. It will be appreciated that this angle may vary from abou 30 - 90°, depending upon the location of the take-up device, and the take- up device may be located in such a manner that the yarn bundle withdrawn via the slot 8 will contact an outer portion of the tubular member. General '.however, it is preferred that the yarn bundle be withdrawn directly throug the slot 8 at such an a gle . as to avoid additional contact with the outside surface of the tubular member in this embodiment of the invention.

Slot 8, as illustrated, has a width that increases from that portion of the slot formed adjacent to end 3 to the other end of the slot which exits

at end 4 of the tubular member. In one specific embodiment of this device, the dimensions of the slot will .have a taper of from 0 to £ of an inch ( 0, 635 cm) per foot ( 30.48 cm) , with a range of from 1716 ( 0. 159 cm) to 3/16 ( 0.4 76 cm) of an inch ( 0. 15875 cm to 0, 47625 cm) being preferred and the length of the slot will vary from 15 to 20 inches ( 38, 1 to 50, 8 cm) or more. In this regard it will be recongized that in this embodiment the length of the tubular member and the slot must be long enough to provide sufficient variation in the tension applied to the yarn bundle and to maintain a yarn having a variable input within the confined space.

It has been found that this embodiment of the apparatus runs particu¬ larly satisfactorily where space is not a limiting factor and where the vari¬ able input of the yarn plug is relatively low . However, when the variable input of the yarn plug is high with a limited amount of space, it has been found that this embodiment of the tubular element does not provide satisfac¬ tory results .

In general, the diameter of this tubular 'element as well as the tubular element shown in the other embodiments illustrated in the drawings must be from about z to l-£ of an inch ( 1, 27 to 3, 175 cm) , The diameter of the tu¬ bular element, that is the inside diameter, is selected so that the diameter of the plug is from 178 to £ of an inch ( 0.3175 to 0.635 cm) greater than the diameter of the plug to provide sufficient space around the plug for the plug to freely move backward and forward within the tubular element.

It should also be appreciated that the dimensions of the width of the slot must be maintained within a range of from about 1716" to 5732" ( 0. 159 to 0, 397 cm) to insure that the surrounding portion of the tubular element will maintain the plug downstream of the yarn withdrawal point in a relative¬ ly compact condition . Also this range of slot dimensions enables the take-up device to supply sufficient tension to the yarn bundle to pull the filaments together and to at least partially straighten out the filaments .

In general in this embodiment of the invention it is preferred to pro¬ vide the slot with such dimensions and a length such that the forward end of the slot, that is near end 3 of the tubular element, will provide a tension t. om 30 to 50 grams to the yarn: whereas the rear end of the slot near end 4 of the tubular element will apply a tension of 5 to 10 grams . Figure 2 ill¬ ustrates the manner in which the yarn is taken from the tubular element th¬ rough the slot 8, which has rounded edges 11 to prevent damaging of the yarn filaments .

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In the embodiment of the tubular element shown in Figure 3, the tub¬ ular element 2 is provided with a slot 12 which is arranged in the form of a helix, with the helix having at least one lead or complete revolution abou the longitudinal axis of the tubular element. Generally in this embodiment of the invention the width of the slot remains the same with a range of fro 1716 to 5/32 of an inch being particularly acceptable ( 0. 159 to 0, 397 cm) an with 3/32" { 0.238 cm) being a preferred width. Moreover, the slot,i.e, th section of the slot having a helical configuration, may be provided with lea of from 2 to 14 inches {5, 08 to 35, 56 cm) long in increments of 1 inch (2.5 cm) . A particularly preferred lead length is 3 inches (7, 62 cm) and usuall one and in some cases two leads are provided in the tubular element. Thu it will be appreciated that where space is a factor a helical slot with a 3 in (7, 62 cm) lead is particularly preferred; whereas, when space is not a lim¬ iting factor, a helical slot with a 14 inch ( 35.56 cm) lead may be employed. It has been found that a tubular element having a lead of either 3 inch (7. 62 cm) or 14 inches (35.56 cm) will provide satisfactory results . According the length of the tubular element may vary from about 5 inches to 20 inche ( 12, 7 to 50.8 cm) in length, Also, the tension applied usually may be from 70 - 100 grams at the front end and 5 to 10 grams at the rear end of the slot,

As also shown in Figure 3, the helical slot forms an angle Θ with the longitudinal axis of the tubular element. It has been found that the angle should be within a range of from about 10° to 45° . At values below 10° th angle Θ of the helical slot causes the length of the tubular element to becom too great for practical applications. At values of the angle Θ greater than 45°, the yarn bundle being pulled off of the yarn plug will not normally fo¬ llow the helical slot. For the purposes of this invention, it is preferred th at the angle Θ is within the range of from 20 to 40° .

It will be observed from Figure 3 that the helical portion of the slot 1 terminates at a zone designated by reference numeral 13 and that from this zone to the end 4 of the tubular element the slot continues in a linear fashi The linear portion of the slot 15 provides a portion in the slot which has a substantially constant tension and, accordingly, provides a confined space iη which the end of the yarn plug may move without causing any variation in the tension.

The tubular element shown in Figure 4 is also provided with a.helical slot designated by reference numeral 11' . This slot has a width that varies

fro the front end of 1716 to 5732 of an inch ( 0. 159 to 0, 397 cm) at the re¬ ar end, with a 1716 of an inch ( 0, 159 cm) front end and a 1/8 of an inch (0, 3175 cm) rear end being preferred, The finish on the outside and in¬ side surfaces of the tubular element is from 4 to 63 RMS, with 16 - 32 RMS being preferred . It will be recognized that the finish of the surface must be selected to insure that the yam is not damaged by rubbing over the sur¬ face and yet the surface must not be so smooth as to reduce the drag effect on the wrap of yarn which ^' causes tension in the yarn.

Figure 5 shows the relative positon of a yarn plug within a tubular ele¬ ment of the type* shown in Figure 3 and the path of a yarn bundle 9 being withdrawn from the plug.

In Figure 6 a tubular element 2 having two leads or complete revolutions of the helical slot is shown in a perspective view with the end of the yarn plug being near the front end of the slot so that a complete wrap 16 of the yarn is formed on the outside surface of the tubular element. This plug po¬ sition provides a tension to the yarn that is approximately half of the maxi¬ mum tension that will be provided by this tubular element. It will also be observed that the position of the yarn plug producing device 6 is also illus¬ trated. This device is of the type described in U. S . Patent No, 3, 983, 610. The yarn bundle is pulled from the tubular element by a take-up godet 10 which is operatively associated with a winding device for forming a yarn pa¬ ckage. In the arrangement of the tubular element shown , it will also be se¬ en that the linear portion 14 on the slot is positioned to be directed toward, i,e, to face , the take-up godet. Generally, the longitudinal axis of the tu¬ bular element and the longitudinal axis of the godet are arranged parallel or at an angle of not more than about 20° and in the same plane. Also the li¬ near portion of the slot as well as the end portion of the helical portion is positioned directly below the outermost edge portion of the godet as further illustrated in Figure 7, The take-up godet is usually spaced from the tubu¬ lar element by a distance of from 1 to 5 feet ( 0, 3048 to 1, 524 cm) to allow the yarn bundle to be pulled from the slot at an angle of from about 30 - 90° to the longitudinal axis of the tubular element. It will be recognized that in this embodiment and all embodiments wherein the yarn bundle is gui¬ ded through a slot having a.helical configuration, the yarn bundle is pulled from the end of yarn plug at an angle of approximately 90° with respect to longitudinal axis of the plug, the yarn then wrapping about a portion of the outer circumference of the tubular element before being pulled out of contact with the tubular element,