CN114057020A

CN114057020A - Device and method for controlling balloon and winding unit comprising such device

Info

Publication number: CN114057020A
Application number: CN202110900177.7A
Authority: CN
Inventors: 毛罗·莫罗; 斯特凡诺·马尔凡特; 詹卢卡·弗莱斯; 曼普雷特·辛格
Original assignee: Savio Macchine Tessili SpA
Current assignee: Savio Macchine Tessili SpA
Priority date: 2020-08-07
Filing date: 2021-08-06
Publication date: 2022-02-18
Also published as: IT202000019660A1; EP3950551A1; CN216471447U

Abstract

The present disclosure relates to an apparatus and a method for controlling a balloon and a winding unit including the same, wherein the apparatus for controlling a balloon includes: -a first restraining element having a longitudinal axis and a through opening adapted to pass the yarn to leave the spool; -a support adapted to support the first restraining element and adapted to be fixed to the structure of the winding unit; wherein the first restriction element comprises a first restriction component and a second restriction component; wherein the support comprises a first arm and a second arm, the first and second limiting members being positioned on the first and second arms, respectively; wherein the device comprises drive means adapted to move the first and second arms, and thereby the first and second limiting members, between the first and second positions; and wherein the device comprises a second restriction element. The device improves productivity and reduces the phenomenon that a plurality of coils are simultaneously dropped from a bobbin and the number of yarn breakage.

Description

Device and method for controlling balloon and winding unit comprising such device

Technical Field

The present invention relates to a device for controlling the balloon during the unwinding of a spool, a winding unit provided with such a device, and a method for controlling the balloon during the unwinding of a spool.

Background

As is known, industrial winding machines comprise a plurality of winding units, independent of each other and controlled by a programmable control unit.

The winding device is used to wind the yarn on a support, usually conical, to produce a spindle to be used for weaving, knitting or other subsequent processing. The yarn is wound on the support with a predetermined winding type to optimize the subsequent unwinding of the yarn from the spindle during the weaving phase.

In this discussion, the term "thread" or "monofilament" or "continuous thread" refers to a single filament or continuous strand (e.g., in the case of silk, rayon, or synthetic fibers), while the term "yarn" refers to a group of fibrils of varying length that are aligned in parallel and joined by twisting. In the following, either term will be used without distinction, it being understood that the application of the invention is not limited to one type or another.

The yarn is preferably wound on the spindle by means of a cylinder in contact with said spindle and rotating about an axis substantially parallel to the axis of the spindle. The drum is provided with a seat of predetermined geometry which engages and guides the yarn during its winding onto the spindle.

It is evident that a high winding speed of the yarn on the spindle corresponds to a high unwinding speed of the spool supplying the yarn.

One of the main consequences of increasing the unwinding speed of the spool is the increase in tension due to the unwinding, which in some cases may cause yarn breakage and in any case is detrimental to the yarn, since defects may increase specific stresses in the contact points of the thread.

The yarn near the bobbin forms a so-called balloon (balloon): the balloon associated with the shape of the yarn wound on the spool becomes wider as the yarn unwinds from the spool, and this widening extends a height above the spool to a cylindrical connection point above the tube. The more the unwinding speed increases, the more the diameter of the balloon increases until it collapses and slides onto the tube, losing its characteristic shape. Basically, as the velocity increases, the centrifugal force is not sufficient to overcome the other forces involved (mainly the coriolis force, but also the aerodynamic drag) and the balloon is close to the tube.

In addition, as the spool is emptied, the tension further increases due to the lowering of the line from the pick-up point of the spool, and the height of the balloon increases therewith, and the balloon may collapse.

The correlation between balloon diameter and tension due to unwinding is well known; in particular, it is known that as the unwinding speed of the spool increases, the balloon diameter increases, and therefore the unwinding tension also increases. In addition, in the case where the balloon collapses, the tension is further increased by the friction generated between the wire and the tube. This friction may especially degrade the yarn.

The prior art attempts to solve this problem by: the diameter of the balloon is attempted to be limited by passing the yarn inside a limiting element (restriction element) which is part of a system called balloon breaker and is substantially cylindrical, coaxial with the spool and located near the upper end of the spool.

When the spool is emptied, the yarn is lowered from the pick-up point of the spool, increasing the height of the balloon and therefore the maximum diameter of the balloon increases until it collapses. This increase in height results in a loss of the restraining effect, significantly reducing the effectiveness of such a system.

For this reason, balloon breakers of the known type provide an additional function, such as a downward movement of the restraining element when the amount of yarn remaining on the spool decreases.

This solution is particularly advantageous since it allows to maintain an optimal distance between the yarn still wound on the spool and the restraining element, thus allowing to optimally restrain the balloon inside the restraining element.

However, this system is technically complex and expensive, since each winder may comprise tens of winding units, and therefore tens of such devices.

In practice, the movement is performed parallel to the direction of movement of the restriction element by means of a motor connected to the screw element, using a so-called screw-nut coupled movement.

The device also comprises a sensor, for example an optical sensor, adapted to detect the height of the portion of the spool covered by the yarn and to transmit this information to a programmable control unit which commands the motor to lower the restriction element accordingly.

Thus, as mentioned above, the solutions proposed by the prior art, although widely used and functional, are not without drawbacks.

First of all, this system is very complex, since it requires continuous monitoring of the winding condition of the yarn on the spool, in order to move the restriction element continuously.

Moreover, as mentioned above, this system is an expensive system, since it envisages the use of an electric motor, a device for converting the rotary motion into a translational motion of the limiting element, and a sensor for evaluating the quantity of yarn wound on the spool.

It is therefore evident that the cost of incorporating these devices into all the winding units has a great impact on the final cost of the winder.

These systems also allow the system to be raised when the yarn breaks, to allow the free pick-up of the thread from the spool with a suitable suction nozzle, or even to provide additional means for retaining the thread.

Furthermore, the reduction in tension achieved for some yarns may deteriorate the hairiness of the yarn due to the friction generated.

Disclosure of Invention

There is therefore a need to at least partially address the disadvantages and limitations noted in the prior art.

Therefore, there is a need to provide a device for controlling the tension of the balloon which enables the unwinding tension to be better managed and the production speed to be increased without increasing the hairiness of the thread. Such a device should have a simpler structure than the devices of the prior art and therefore be easy and inexpensive to implement in the winding unit.

Furthermore, from the viewpoint of simplifying the structure of the device, there is a need for a system that does not require the use of additional sensors to establish the winding condition of the yarn on the spool.

Furthermore, there is a need for a more efficient means for controlling the balloon than prior art devices.

The present disclosure relates to a device for controlling a balloon during unwinding of a yarn from a spool in a winding unit, comprising: -a first substantially tubular restraining element having a longitudinal axis and a through opening adapted to pass the yarn to exit the spool; -a support adapted to support the first restraining element and to be fixed to a structure of the winding unit; wherein the first restriction element comprises a first restriction component and a second restriction component; wherein the support comprises a first arm on which the first restraining component is positioned and a second arm on which the second restraining component is positioned; wherein the means for controlling the balloon comprises a drive adapted to move the first and second arms and thereby the first and second confinement members between: a first position in which the first and second limiting members are spaced apart; and a second position in which the first and second limiting members are closer together relative to the first position; and wherein said means for controlling the balloon comprise a stationary second restriction element arranged downstream of said first restriction element, said second restriction element being arranged with a second through opening comprising a base portion facing, in use, said first restriction element, said base portion having a substantially rectangular cross-section with respect to said longitudinal axis.

The present disclosure also relates to a winding unit comprising the aforementioned device for controlling the balloon during unwinding of the yarn from the spool.

The present disclosure also relates to a method for controlling a balloon by the aforementioned apparatus for controlling a balloon, the method comprising: measuring an operating parameter during unwinding of the yarn from the spool; comparing the operating parameter to a predetermined value for the operating parameter; operating the first limiting element based on the comparison in step b such that the first limiting member and the second limiting member move from the first position to the second position or, if an intermediate position is present, to the intermediate position.

The apparatus and method for controlling the balloon allow productivity to be improved and reduce the phenomenon that several coils are simultaneously dropped from the bobbin and the number of yarn breakage.

Drawings

Other features and advantages of the present invention will become more apparent from the following detailed description of preferred, non-limiting embodiments of the invention, in which:

figure 1 schematically shows a front view of a device for controlling a balloon according to the invention;

figure 2 schematically shows a perspective view of a device for controlling a balloon according to the invention;

figure 3 schematically shows a perspective view of a device for controlling a balloon according to the invention;

fig. 4a, 4b and 4c schematically show three possible unwinding steps according to an embodiment of the method for unwinding a yarn from a spool according to the present invention;

figure 5 schematically shows a front view in cross-section of a part of a device for controlling a balloon according to the invention;

FIG. 6 schematically illustrates a front view of an apparatus for controlling a balloon in accordance with the present invention;

figure 7 schematically shows a front view in cross-section of a component of a device for controlling a balloon according to the invention;

figure 8 schematically shows a perspective view of a component of a device for controlling a balloon according to the invention;

figure 9 schematically shows a plan view from above of a part of a device for controlling a balloon according to the invention;

figure 10 schematically shows a plan view from below of a part of a device for controlling a balloon according to the invention; and

figure 11 schematically shows a front view of a part of a device for controlling a balloon according to the invention.

Hereinafter, the same elements or portions of elements as those of the described embodiments will be denoted by the same reference numerals.

Detailed Description

In fig. 1, reference numeral 12 is used to generally indicate a device for controlling the balloon during unwinding of the yarn 14 from the spool 16 in the winding unit 18.

The means 12 for controlling the balloon comprise:

a first substantially tubular restraining element (20) having a longitudinal axis X and a through opening 22 suitable for the passage of the yarn 14 to be taken off the spool 16; and

a support 24 adapted to support the first limiting element 20 and to be fixed to the structure of the winding unit 18.

As shown, the first restriction element 20 includes a first restriction member 120 and a second restriction member 220. Further, the support 24 includes a first arm 124 and a second arm 224 on which the first limiting member 120 and the second limiting member 220 are positioned, respectively.

The means 12 for controlling the balloon comprise a drive means 26 adapted to move the first arm 124, the second arm 224 and, consequently, the first 120, the second 220 limiting member between: a first position in which the first and second limiting

members

120, 220 are spaced apart from each other; and a second position in which the first limiting member 120, the second limiting member 220 are closer together relative to the first position.

According to one possible embodiment, in the second position, the first limiting member 120 and the second limiting member 220 may contact each other.

In other words, in the first position, the first and

second restraining components

120, 220 may be spaced apart so as to not substantially interact with the balloon formed during unwinding of the yarn 14 from the spool 16.

While in the second position, the first and

second restraining components

120, 220 may be closer together and may contact each other to substantially interact with the air pockets formed during unwinding of the yarn 14 from the spool 16.

According to one possible embodiment, one or more intermediate positions may be provided between the first and second positions of the first and second limiting

members

120, 220, in order to allow the confinement of the balloon according to its size.

According to one possible embodiment, in the second position, the through opening 22 may be substantially cylindrical and have a flared portion 28 at the input portion of the yarn 14.

In fact, as shown for example in fig. 1 or 2, the first 120, second 220 limiting members may have a widening and therefore the diameter of the through opening 22 increases at the input portion of the yarn 14.

According to one possible embodiment, the through opening 22 may have a narrowing 29 at a position opposite to the input of the yarn of the through opening 22.

According to a possible embodiment, which can be seen for example in fig. 3, the first arm 124 and the second arm 224 can rotate in opposite directions about respective rotation axes Y, Z, spaced from each other and substantially parallel to said axis X.

The first and

second arms

124, 224 may be provided with

cogwheels

126, 226 integral with their respective arms, which are in mesh with each other and adapted to rotate about their respective axes Y, Z, such that rotation of one arm causes rotation of the other arm, and thus the rotations are synchronized.

One such embodiment is shown, for example, in fig. 9, in which

cogwheels

126, 226 are shown, which may also be incomplete and provided only at a portion of their periphery.

According to one possible alternative embodiment, the drive means may comprise an alternative system of

cogwheels

126, 226, such as an articulated quadrilateral kinematic motion or a crank mechanism.

According to one possible embodiment, the drive means 26 may comprise a linear actuator 260 connected to the second one of the arms 224, which linear actuator is connected to a lever 128 provided on the second arm 224, whereby linear movement of one operating end of the linear actuator 260 causes the second arm 224 to rotate and thus the first arm 124 to rotate.

The linear actuator may be, for example, a pneumatic actuator or an electric actuator, which is known per se to the person skilled in the art.

According to alternative embodiments, the first arm 124, the second arm 224 may be driven in different technical ways, for example by using a rotary actuator or the like. Also in this case, the actuators used may be pneumatic or electric, for example.

More specifically, it is also conceivable to provide two actuators, one for each arm. In this case, the arm may also be uncoupled from the cogwheel.

According to an alternative embodiment, the driving device 26 may be adapted to move the first limiting member 120, the second limiting member 220 in a linear direction. For example, a linear actuator shared by both the first restriction member 120, the second restriction member 220, or a linear actuator for each linear element may be provided.

Furthermore, the driving means may be adapted to achieve asynchronous movement of the first restriction member 120, the second restriction member 220.

In a further alternative embodiment, the linear actuator may, for example, be directly keyed to one of the limiting members and, by means of a mechanical transmission, may also move the other limiting member.

The means 12 for controlling the balloon comprise a stationary second restriction element 50 arranged downstream of the first restriction element 20, which second restriction element comprises a second through opening 52 arranged with a base portion 54 facing, in use, the first restriction element 20, the base portion having a substantially rectangular cross section with respect to the longitudinal axis X.

Advantageously, the second limiting element 50 can be arranged on the same support 24 as the first limiting element 20.

According to one possible embodiment, the base portion 54 of the second through opening 52 may have a substantially square cross section. More particularly, the base portion may have a substantially square cross-section with sides of the square having a dimension of 20mm to 30mm, preferably 24mm to 28mm, even more preferably about 26 mm. Furthermore, the height of the base portion 54 of the second through opening 52 may be 30mm to 45mm, and preferably 35mm to 40mm, in a longitudinal direction perpendicular to the cross section of the second through opening 52.

According to one possible embodiment, the substantially rectangular or square cross-section may comprise an inward projection at the midpoint of each side constituting the rectangular or square cross-section.

The second through opening 52 may comprise a central portion 56 having a substantially truncated pyramidal shape with a larger base in a position in which the base portion 54 is opposite to the input section of the yarn in the second limiting element 50.

According to one possible embodiment, the central portion 56 of the truncated pyramid comprises a smaller base, having a substantially circular shape, opposite to the larger base. The second through opening 52 may also include a substantially cylindrical final portion 58.

In other words, according to one possible embodiment, during the unwinding phase of the spool, the yarn 14 can pass inside the first restraining element 20 and subsequently inside the second restraining element, in particular inside the base portion 54, the central portion 56 and the final portion 58.

As shown in fig. 10, the sides of the cross-section of the second restriction element 50 may, for example, be joined together such that there is no inner edge.

In fact, it is due to the rectangular or square cross section that the continuity of the balloon is interrupted during its formation (fig. 4 a). More specifically, the continuous friction and impact of the yarn on the sides of the restraining element delays the formation of the balloon and, therefore, the increase of the longitudinal tension component of the yarn.

As the amount of yarn in the spool decreases, the balloon tends to form in a lower position than before.

In fact, it can be seen that in the first part of the spool unwinding (fig. 4a), the confinement of the balloon is not as effective as the continuous destruction by the second confinement element 50. Thus, since the height of the balloon is limited, the tension can be limited.

Once the spool begins to empty, for example approximately half way through the spool, the second restriction element 50 fails as the balloon height increases (and therefore the yarn tension increases).

This height causes the wire to slide over the top end of the tube and thus no longer to be in contact with the inner surface of the second limiting element 50 (fig. 4 b).

At this point, the first restriction element 20 is closed in the second position.

The method for controlling the balloon by means of the device 12 for controlling the balloon mainly comprises:

step a. measuring operating parameters during unwinding of the yarn 14 from the spool 16;

step b-comparing the operating parameter with a predetermined value of the operating parameter, for example in a programmable control unit (not shown in the figures); and

based on the comparison in step b, the first restriction element 20 is actuated such that the first restriction member 120 and the second restriction member 220 move from the first position to the second position, or to an intermediate position (if present).

According to one embodiment, the operating parameter used may be the percentage of yarn unwound from the spool.

According to a possible alternative embodiment, the operating parameter may be, for example, the yarn tension measured downstream of the device 12 for controlling the balloon.

Thus, the first restriction element 20 can be actuated from the first position to the second position, or to an intermediate position (if present), when the yarn tension measured downstream of the device exceeds a certain value.

Furthermore, in order to prevent tension peaks from impairing an effective actuation of the first restriction element, the actuation of the restriction element from the first position to the second position or to an intermediate position (if present) may be performed a predetermined number of times or for a predetermined time period beyond a certain tension value.

In this way, temporary disturbances in the system can be prevented from impairing the winding.

For example, a wire tension adjustment system already installed on the winder may be used. In practice, the wire tensioning system generally operates between a minimum and a maximum value corresponding to a maximum winding tension and a minimum winding tension, respectively, and with which the winding speed and the actuation of the first limiting element can be regulated.

In particular, a thread tension adjustment system may be used such that the first limiting element is actuated when the thread tensioner is operated around a minimum value (corresponding to a high winding tension), or when a certain value is exceeded a predetermined number of times or a predetermined length of time.

As regards the adjustment of the distance between the means 12 for controlling the balloon and the spool, this depends on the unwinding parameters, as will be apparent to the skilled person. More specifically, the distance between the device and the tube of the spool can be adjusted according to, for example, the behavior of the balloon and the yarn count at a certain unwinding speed.

For example, the distance between the second restriction element and the tube of the bobbin may be about 10-30mm, while the distance between the first restriction element and the second restriction element may be about 4-12 mm.

According to one possible embodiment, the distance between the end of the tube of the spool and the narrowing 29 of the first restriction element may be 4mm to 12 mm.

According to one possible embodiment, the through opening 22 may have a diameter of about 26-42 mm. The diameter of the narrowed portion 29 may be about 22-40 mm.

In the figures, only a part of the winding unit is shown, at least because other components are known per se to the person skilled in the art.

The advantages of the method according to the invention are therefore also now apparent.

First, there has been provided an apparatus and method for controlling a balloon, which allows more efficient control than the related art apparatus.

In particular, unlike the devices of the prior art, the balloon is controlled indirectly by measuring the tension of the yarn during the step of unwinding from the spool.

In other words, no dedicated optical sensor or the like is used to determine the degree of filling or balloon state of the bobbin.

Advantageously, the first limiting member 120 and the second limiting member 220 are closed just above the position where the yarn is separated from the wound coil. This creates a controlled tension that is sufficient to avoid rubbing against the tube, but not so high as to unwind several loops at a time, or even worse, break the yarn.

The main advantages that can be achieved are therefore the stability and the reduction of the unwinding tension, the fluctuations of which can subject the yarn to stresses during said unwinding. In this way, it is possible to increase the unwinding speed in the final step, even by 30-40%.

The result is an increase in productivity because conventional winding systems conversely reduce winding speed.

In addition, the phenomenon that a plurality of coils are simultaneously dropped from the bobbin is continuously reduced, and the number of yarn breakage is reduced.

It will be understood by those skilled in the art that various changes in the described embodiments may be made and equivalents may be substituted for elements thereof without departing from the scope of the appended claims.

Claims

1. A device (12) for controlling the balloon in a winding unit (18) during unwinding of a yarn (14) from a spool (16), said device comprising:

-a first substantially tubular restraining element (20) having a longitudinal axis (X) and a through opening (22) suitable for passing a yarn (14) to exit from the spool (16);

-a support (24) adapted to support the first restraining element (20) and to be fixed to a structure of the winding unit (18);

wherein the first restriction element (20) comprises a first restriction member (120) and a second restriction member (220);

wherein the support (24) comprises a first arm (124) on which the first restraining component (120) is positioned and a second arm (224) on which the second restraining component (220) is positioned;

wherein the means (12) for controlling the balloon comprise drive means (26) adapted to move the first arm (124) and the second arm (224) and, consequently, the first limiting member (120) and the second limiting member (220) between: a first position in which the first limiting member (120) and the second limiting member (220) are spaced apart; and a second position in which the first limiting member (120) and the second limiting member (220) are closer together relative to the first position; and is

Wherein the means (12) for controlling the balloon comprise a stationary second restriction element (50) arranged downstream of the first restriction element (20), the second restriction element (50) being arranged with a second through opening (52) comprising a base portion (54) facing, in use, the first restriction element (20), the base portion having a substantially rectangular cross section with respect to the longitudinal axis (X).

2. Device (12) for controlling a balloon according to the preceding claim, characterized in that in the second position the first limiting member (120) and the second limiting member (220) are in contact with each other.

3. Device (12) for controlling the balloon according to any one of the preceding claims, characterized in that the first limiting member (120) and the second limiting member (220) have a widening and therefore the diameter of the through opening (22) increases at the input portion of the yarn (14).

4. Device (12) for controlling ballooning according to any one of the preceding claims, wherein the first arm (124) and the second arm (224) rotate in opposite directions about respective axes of rotation (Y, Z) that are spaced apart and substantially parallel to the longitudinal axis (X).

5. Device (12) for controlling the balloon according to the preceding claim, characterized in that said first arm (124) and said second arm (224) are provided with cogwheels (126, 226) integral with the respective arms, which are meshed with each other and are adapted to rotate about the respective axis of rotation (Y, Z), so that the rotation of said first arm (124) and of said second arm (224) is synchronized.

6. Device (12) for controlling a balloon according to the preceding claim, characterized in that said driving means (26) comprise a linear actuator (260) connected to said second arm (224), said linear actuator (260) being connected to a lever (128) provided on said second arm (224) so that a linear movement of one operating end of said linear actuator (260) causes a rotation of said first arm (124).

7. Device (12) for controlling the balloon according to any of the previous claims, characterized in that said driving means (26) comprise an actuator of the electric type for moving said first limiting member (120) and said second limiting member (220).

8. Device (12) for controlling ballooning according to any one of the preceding claims, wherein the base portion (54) of the second through opening (52) has a substantially square cross-section.

9. Device for controlling the balloon according to the preceding claim, characterized in that the dimension of the side of the substantially square cross section of the second through opening (52) is between 20mm and 30mm, preferably between 24mm and 28mm, even more preferably about 26 mm.

10. Device for controlling a balloon according to any one of the preceding claims, characterized in that the height of the base portion (54) of the second through opening (52) in a longitudinal direction perpendicular to the cross section of the second through opening is 30mm to 45mm, preferably 35mm to 40 mm.

11. Device for controlling a balloon according to any one of the preceding claims, characterized in that the second through opening (52) comprises a central portion (56) of substantially truncated pyramidal shape having a larger base at the base portion (54) in a position opposite to the input section of the yarn into the second restraining element (50).

12. Device (12) for controlling ballooning according to the preceding claim, wherein the central portion (56) of the truncated pyramid shape includes a smaller base having a substantially circular shape, opposite the larger base.

13. Device for controlling a balloon according to any one of the preceding claims, characterized in that the second through opening (52) comprises a substantially cylindrical final portion (58).

14. An apparatus for controlling a balloon according to any of the preceding claims, characterized in that the apparatus comprises a programmable control unit adapted to compare a measured operating parameter value with a reference value and, based on the comparison, to operate the first restriction element (20) accordingly such that the first restriction member (120) and the second restriction member (220) move from the first position to the second position or, in case of an intermediate position, to the intermediate position.

15. Winding unit (18) comprising a device (12) for controlling the balloon during unwinding of the yarn (14) from the spool (16) according to any one of the preceding claims.

16. Method for controlling the balloon by means of a device (12) for controlling the balloon according to any one of claims 1 to 14, characterized in that it comprises:

measuring an operating parameter during unwinding of the yarn (14) from the spool (16);

comparing the operating parameter to a predetermined value for the operating parameter; and

operating the first limiting element (20) based on the comparison in step b such that the first limiting member (120) and the second limiting member (220) move from the first position to the second position or, if an intermediate position is present, to the intermediate position.

17. Method for controlling the balloon according to the preceding claim, characterized in that said operating parameter is the yarn tension measured downstream of said device (12) for controlling the balloon.

18. Method for controlling a balloon according to any one of claims 16 to 17, characterized in that the actuation of the first restriction element from the first position to the second position or, in the presence of an intermediate position, to the intermediate position takes place when the yarn tension measured downstream of the device for controlling a balloon exceeds a certain value.

19. Method for controlling a balloon according to any one of claims 16 to 18, characterized in that the actuation of the first restriction element from the first position to the second position or, if an intermediate position is present, to the intermediate position takes place when a specific yarn tension value is exceeded a predetermined number of times or for a predetermined length of time.

20. Method for controlling a balloon according to claim 16, characterized in that the actuation of the first restriction element from the first position to the second position or, in the presence of an intermediate position, to the intermediate position occurs when more than a certain percentage of the yarn being unwound.