WO2003085180A1

WO2003085180A1 - Unwinding and balloon-separating device for twisting/doubling machines for yarns

Info

Publication number: WO2003085180A1
Application number: PCT/IB2003/001218
Authority: WO
Inventors: Solitario Nesti; Marco Barbieri
Original assignee: Tecnotessile Società Nazionale Di Ricerca Tecnologica r.l.
Priority date: 2002-04-04
Filing date: 2003-04-03
Publication date: 2003-10-16
Also published as: ITUD20020074A1; AU2003219349A1

Abstract

Unwinding-separating device (10) for twisting/doubling assemblies (20) for yarns (11) wound in bobbins (12), in which each of the yarns (11) defines a first inner segment (11a), and a second outer segment (11b) that under normal working conditions constitutes the balloon. The unwinding-separating device (10) is assembled rotatable in correspondence with one end of the bobbin (12) and comprises a first thread-guide element (14) in which the first inner segment (11a) of yarn passes. The first thread-guide element (14) is supported by a circular element (16) mounted coaxial with the bobbin (12). The circular element (16) is provided with separation means (13) able to separate the first inner segment (11a) from the second outer segment (11b) of the yarn.

Description

" UNWIND ING AND BALL O ON - S E PARAT ING DEVI C E F OR TWISTING /DOUBLING MACHINES FOR YARNS "

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FIELD OF THE INVENTION The present invention concerns an unwinding and balloon-separating device for machines able to twist or double yarns (single, plied or multiple) . The device is able to unwind the yarn from a bobbin and guide it during processing. To be more exact, the device according to the invention comprises at least a movable guide element, conveniently installed coaxial with the bobbin on which the yarn is wound, and able to guide the first segment of said yarn, keeping it distanced from the surface of the bobbin. The present invention also provides to keep said first segment, as it is detached from the bobbin, separate from the outer balloon formed by the same yarn.

BACKGROUND OF THE INVENTION Twisting/doubling is carried out on yarns in order to confer greater resistance, stability of size and particular aesthetic characteristics.

In general, twisting is defined as the process carried out on yarns that have no twist (zero twist yarns) . Doubling is defined as the process carried out on yarns that have twists, even if an extremely limited number thereof.

Twisting/doubling can also be carried out on threads of yarn of different nature (count, material) ; in this case we talk about coupled yarns, plied yarns and in general multiple yarns . In practice, multiple yarns are much more difficult to work, essentially due to the different nature of the threads that make up the multiple yarns .

This entails a greater attention in performing the process and using technical solutions and specific equipment able to limit breakages and entanglement.

In practice, machines that perform twisting/doubling are based on different principles, for each of which products with different characteristics are obtained

(hollow spindle, fancy doublers, two-for-one twisters/doublers, etc.).

In twisting/doubling systems it is necessary to reel off a yarn from a bobbin, make it describe one or more complete loops around the bobbin on a plane on which the axis of the bobbin lies, so as to define several segments of yarn having a direction of advance essentially parallel to said axis. In the case of two-for-one twisting/doubling, it is typical to collect the yarn at the top, and hence have two ascending segments with a descending segment in between that follows the axis of the bobbin, whose yarn is wound around a hollow support (cop) , able to make the descending segment of the yarn pass.

In the case of single thread yarns it is sufficient to assemble above the cop, in correspondence with its axis, an element that essentially carries a thread guide connecting the first ascending segment with the descending segment. During "defile" off-reeling, the first ascending segment can be returned directly along the axis of the bobbin without particular risks of overlapping due to the displacement of the spirals below along the outer face of the bobbin.

To work bobbins which carry multiple yarns (typically plied) , "defile" off-reeling leads to considerable problems in feeding the yarns with risks of displacing and overlapping the following and underlying spirals (and hence of breaking the yarn or even making the bobbin unusable) ; it requires that the yarns are extracted in a direction which comprises a considerable radial component. This makes it necessary to use not only the already mentioned thread guide between the first ascending segment and the descending segment, but also an eyelet located outside the bobbin so as to distance the ascending segment from the outer surface of the bobbin. Typically, this eyelet is mounted on a so-called rotary unwinder that performs this task. The unwinder is mounted rotatable above the cop and positioned axially on the twisting/doubling assembly, so as to be able to follow the rotation of the yarn which is unwinding. In the rest of the text twisting shall mean both twisting proper, and also doubling.

The presence of this device creates interference, at the start of the process, with the path of the second ascending segment, when the centrifugal actions on said segment are not yet such as to allow a balloon to form. In fact, the trajectory of the second segment of ascending yarn interferes with the unwinder and prevents it from moving . For a correct start-up it is necessary to equip the individual twisting assembly with a further device able to keep separate the second ascending segment from the trajectory described by the parts which make up the unwinder. Such device (which some call a basket) must have an upper edge which is higher than the circular trajectory of the unwinder, and is very expensive.

Moreover, in current twisting assemblies, in order to control the tension of the balloon, and hence the homogeneity of the torsions conferred on the yarn, a device to brake the yarn is located in a rod inserted inside the cavity of the cop of the bobbin being processed, along the path of the descending segment. When the machine has to process yarns with different counts, it is necessary to intervene to regulate the braking action (for example by regulating a spring or modifying the number of braking balls that make up the system) , dis-assembling and reassembling the rod. In order to accelerate the change of count, it may become convenient to store several collections of pre-calibrated rods, in number equal to the number of heads of the machine multiplied by the number of most frequent ranges of count. Likewise, the braking action obtained by the methods cited above generates a tension that depends on the section and the type of the yarns and may be differentiated in the threads that make up the multiple yarn, with a resulting non-homogeneous distribution of the twists.

For the reasons given above, it is obvious that twisting machines offer great versatility, but in practice it is necessary to have available a considerable number of accessory devices, some of which are delicate and expensive, thus immobilizing capital and also requiring considerable time and labor for the various fittings. Moreover, in operations to replace the bobbin, with the same count (removing the empty cop and loading the full bobbin) , while for the single yarn it is enough to lift the element that carries the thread guide between the first ascending segment and the descending segment, to remove the cop, insert the bobbin, re-position the element and thread the yarn along the whole path, for multiple yarns the operations are made more complex because of the presence of the unwinder, but especially because of the basket, which with its edge can damage the bobbin, ₍ even irremediably, if the latter is not inserted inside the basket with the greatest of care.

SUMMARY OF THE INVENTION The present invention is set forth and characterized essentially in the main claim, while the dependent claims describe other innovative characteristics of the invention. The main purpose of the invention is to achieve a reeling-off device with the additional function of separating the two segments of ascending yarn, making it superfluous to include the basket for separating the balloon.

Another purpose of the invention is to reel off yarns wound on a bobbin in a controlled manner, particularly with regard to the tension of the yarn.

Moreover, the invention proposes geometric characteristics, and characteristics for the distribution of the mass, which facilitate the balancing of the device.

This improves the stability, during working, of the parameters that affect the characteristics of the product.

A final purpose of the present invention is to propose a simple device, inexpensive to make, strong in structure and able to withstand the stresses imposed by industrial use . The device according to the invention is able to be assembled on a twisting machine wherein, in the case of two-for-one twisting, the yarn is able to define at least a first ascending segment and a second ascending segment outside the first. To be more exact, the device is assembled in removable fashion above the cop, so that it can rotate with respect thereto so as to allow the guided unwinding of a single or multiple yarn wound on a bobbin.

In accordance with these purposes, the unwinding- separating device according to the present invention comprises a circular element, which forms the main body, able to be assembled coaxial with the bobbin.

The circular element is able to separate the first inner ascending segment of the yarn from the second outer ascending segment of the yarn.

This circular element is also provided with an outer protection edge, the function of which is to diminish the friction that is generated due to contact, in the initial working step which precedes the formation of the balloon, between the outer ascending segment of yarn and the circular element itself.

The circular element is equipped with one or more thread-guide eyelets that perform the function of guiding the segment of yarn exiting the bobbin with a radial component, thus preventing the yarn which has just been reeled off from sliding on the bobbin.

The circular element thus performs different functions: reeling off the bobbin, directing the segment exiting therefrom, guiding the first ascending segment, and finally separating the two ascending segments of yarn, inner and outer, and keeping them at a distance, thus making it possible for the outer ascending yarn to slide on the protection edge, allowing said yarn a movement without interference.

The circular element, due to its geometry, also guarantees the unwinding-separating device a balanced rotation with respect to the axis of rotation.

According to a preferential form of embodiment, the circular element can consist of a revolution surface with a conical, truncated cone , cylindrical, or bell shape.

The circular element can advantageously be shaped according to the shape of the upper part of the bobbin, so that the second ascending segment is not subjected to superfluous contacts.

At least one thread-guide eyelet able to distance the yarn in the first ascending segment will conveniently be located in correspondence with the cylindrical zone of the bobbin .

In order to facilitate the rotation of the unwinding- separating device around the bobbin axis, sliding means are provided, consisting of sliding or rolling bearings of various types; for example, bushings made of self- lubricating material, which wear regularly thanks to the balance conferred by the circular element.

The unwinding-separating device according to the present invention is therefore perfectly balanced during movement, since as a consequence of its substantially circular shape and its coaxial arrangement with respect to the bobbin, its baricenter lies constantly on the longitudinal axis of the bobbin.

In order to control the tension conferred on the yarn, it is possible, depending on the type and speed of the process, to intervene on the braking of the unwinding- separating device, essentially modifying the grazing friction produced by the sliding components possibly included (modifying the surfaces and/or the weight of the device by means of additional weights), or by regulating the fluid-dynamic friction that is generated during movement (modifying the shape, for example by inserting fins of different sizes), or again by introducing a magnetic braking system. Since the unwinding-separating device is substantially balanced, the friction generated during movement is also constant, and consequently the tension conferred on the yarn, which is a fundamental parameter for the purposes of obtaining homogeneous characteristics of the product, remains constant, thus allowing a greater guarantee of quality to the final product.

BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein: - fig. 1 is a lateral view of a double twisting/doubling assembly for a yarn, to which the unwinding-separating device according to the present invention has been ap lied;

- fig. 2 shows an enlarged detail of fig. 1; - fig. 3 shows an enlarged detail of fig 2 ;

^• - fig. 4 shows an enlarged detail of a first variant of the device in fig. 1;

- fig. 5 shows an enlarged detail of a second variant of the device in fig. 1 ; - fig. 6 shows a third variant of the device in fig. 1;

- fig. 7 shows a fourth variant of the device in fig. 1.

DETAILED DESCRIPTION OF A PREFERENTIAL EMBODIMENT With reference to fig. 1, an unwinding-separating device 10 according to the present invention is assembled on a double twisting assembly 20 of a conventional type. It is clear that the device 10 can also be assembled on different twisting assemblies other than the unit 20 shown here.

The double twisting assembly 20 comprises a cop 21 on the outer surface of which a yarn 11 is wound, so as to form a bobbin 12.

The cop 21 is generally made of plastic material and is substantially tubular in shape, so as to define a cavity 24 inside which there is a rod inside which the yarn 11 is made to pass.

The bobbin 12 typically has two end zones, respectively upper 12a and lower 12b, in which the yarn 11 is wound so as to define a truncated cone shape, whereas, in the remaining central part, the bobbin 12 is substantially cylindrical in shape.

The device 10 comprises a circular element 16 (fig. 2) shaped like a truncated cone and having a ring 13 and a disk 18 substantially parallel to each other, and also connection spokes 19 connecting the ring 13 and the disk 18.

The ring 13 supports a thread-guide eyelet 14 lined internally with an anti-friction material, inside which the yarn 11 is able to pass as it arrives directly from the bobbin 12.

The ring 13 is provided with a protection edge 15 equipped ,-with a circumferential segment 15a (fig. 3) consisting of a material with a low friction coefficient, such as for example Teflon, steel, ceramic or similar. The ring 13 is able to prevent the yarn 11, outside the ring 13, from coming into contact with the bobbin 12. In this way, moreover, both the unwinding-separating device 10 and the balloon of yarn 11 are each free to make their own movement, without reciprocal interference.

As shown in figs. 3 to 5 , the circumferential segment 15a can be made in various ways: for example, as shown in fig. 3, it can have an additional element 115 consisting of a steel round piece arranged along the whole circumference; or, as shown in fig. 4, it can be made with a ring nut 215, for example made of Teflon, attached to the inner wall of the ring 13; or, as shown in fig. 5, it can be made directly on the edge 15, making a rounded edge 315 with a reduced radius . The circular element 16 can be made in various ways, for example by assembling several parts (disk 18, ring 13 and spokes 19) or in a single piece, wherein the spokes are made by making apertures on the conical surface. A variant not shown in the drawings may also provide that the conical surface remain whole.

On the disk 18 of the circular element 16 a second thread-guide eyelet 17 (fig. 2) may optionally be assembled; it is positioned for example on the same axial plane on which the eyelet 14 is located, and is lined internally with an anti-friction material. According to a variant, not shown in the drawings, the second eyelet 17 can be replaced by a simple hole, inside which the segment of yarn 11a arriving from the eyelet 14 is able to pass.

According to a variant, not shown in the drawings, the second eyelet 17 can be positioned not on the same axial plane on which the first eyelet 14 is located, but in a tangentially more advanced position, such as to increase the tangential components of the actions of the yarn with respect to the circular element 16, thus facilitating the drawing thereof.

The device 10 also comprises sliding means 30 which cooperate with the double twisting assembly 20 to allow the free rotation of the circular element 16 with respect to the latter.

To be more exact, the double twisting assembly 20 comprises a hollow tube 32 coaxial with the cavity 24 and able to make the latter communicate with the outside. The hollow tube 32 is normally made of metal and, on its upper end, has an axially hollow head 33, attached to the tube 32 by means of for example a threaded grub screw.

In the axial cavity of the head 33 a threading eyelet 34, typically made of ceramic, is inserted at least partly and with a slight play; the yarn 11 arriving from the eyelet 17 is able to slide on said threading eyelet 34 and is able to be inserted into the tube 32 to reach the cavity 24. A metal spacer 23 is assembled integral in correspondence with the upper end of the cop 21.

The sliding means 30 comprise a pair of bushings 35 and 36 arranged coaxial to each other in correspondence with the upper end of a hub 31 integral with the circular element 16 and, respectively, in correspondence with the lower end of said hub 31. The bushings 35 and 36 are advantageously made of plastic material, or in any case of material more subject to wear than that with which the spacer 23 is made.

Each bushing 35, 36 comprises a tubular part 35a, respectively 36a, located between the hub 31 and the tube 32. To be more exact, the bushing 36 also comprises an abutment disk 36b substantially perpendicular to the longitudinal axis of the cop 21 and associated orthogonally with the tubular part 36a. The abutment disk 36b of the bushing 36 is located between the circular element 16 and the metal spacer 23 to allow the circular element 16 to rotate with respect to the cop 21. The bushings 35 and 36 allow the circular element 16 to follow the rotation of the yarn 11 around the bobbin 12 as it is reeled off and to keep the circular element 16 constantly coaxial with the longitudinal axis of the cop 21.

According to a variant, not shown in the drawings, the abutment disk 36b can be made of a metal with a low friction coefficient or sintered self-lubricating or comprise a fluid-dynamic sustentation system.

According to another variant, not shown in the drawings either, the sliding means 30 can be made in a single piece on the circular element 16.

As a consequence of the axial symmetrical structure of the device 10, its rotation occurs in a substantially balanced manner, and hence the bushing 36 wears its abutment disk 36b slowly and regularly; during rotation, the abutment disk 36b rubs against the spacer 23, which stays still.

The device 10 as described heretofore, applied on the double twisting assembly 20, functions as follows.

The thread of the yarn 11 of the bobbin 12 to be reeled off is first made to pass inside the thread-guide eyelet 14 and then through the second eyelet 17, so as to form a first ascending segment 11a of the yarn 11. The yarn 11 is then made to pass inside the tube 32, through the threading eyelet 34, and then inside the cavity 24, until it reaches, through a passage that is normally included on twisting machines, the outer zone, in the lower part of the cop. The yarn 11 is then made to rise to a removal pipe 37, arranged above the tube 32 and coaxial therewith, so as thus to define a second ascending segment lib outside the first ascending segment 11a.

When the yarn is returned by the collection members located above the pipe 37 (of a conventional type and not shown in the drawings) , the tension is transmitted to the second ascending segment lib which, stretching between two points that are located at lesser distances from the axis of the cop than the protection edge 15 of the ring 13, comes into contact with said edge 15. Then the tension is transmitted to the descending segment that, by means of the threading eyelet 34, puts under tension the first ascending segment 11a. The segment between the eyelet 14 and the bobbin 12 is tensed, making the circular element 16 rotate. This rotation allows the yarn 11 to unwind from the bobbin 12, and guides it. At start of process, the segment of ascending yarn lib remains in contact with the edge 15, until it becomes detached due to the formation of the balloon .

The rotation of the circular element 16 causes the abutment disk 36b of the bushing 36 to rub against the metal spacer 23, and the consequent wear of the abutment disk 36b. The rotation also causes the wear of the cylindrical surfaces 35a and 36a against the tube 32. This wear occurs very slowly and regularly, without influencing the functioning of the other components of the device 10.

Moreover, the edge 15 creates a protection which prevents the first ascending segment 11a from entering into contact, even by chance, with the second ascending segment lib, thus preventing the two segments 11a and lib from becoming entangled together.

According to a variant, shown in fig. 6, the thread- guide eyelet 14 can carry the yarn from inside to outside the circular element 16, and the disk 18 can have a lesser diameter, so that the segment 11a of the yarn can be directed towards the threading eyelet 34 without needing the second eyelet 17. According to another variant, shown in fig. 7, the unwinding-separating device 10 can be assembled on a multiple twisting assembly, in which the descending segment does not follow the axis of the bobbin but creates a balloon. In this case the tube 32 keeps its function of guiding the circular element 16, but it does not need to be hollow. The variant requires that the hub 31 extends beyond the end of the tube 32 and bears along its outer wall an aperture 39 in order to allow the segment 11a to pass inside the hub, and then exit therefrom through a threading eyelet 34 located at the top of the hub, from which it then proceeds to form the balloon.

It is clear, however, that modifications and/or additions of parts can be made to the device 10 as described heretofore, without departing from the field and scope of the present invention. For example, supplementary weights and/or fins and/or magnetic systems to regulate the braking of the yarn can be added to the device (for example on the upper disk of the truncated cone, but not only) .

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill shall be able to achieve many other equivalent forms of unwinding-separating device for twisting/doubling machines, all of which shall come within the field and scope of the present invention.

Claims

1 - Unwinding-separating device for twisting/doubling assemblies (20) for yarns (11) wound in bobbins (12), in which each of said yarns (11) defines at least a first inner segment (11a) , and a second outer segment (lib) which under normal working conditions constitutes the balloon, said unwinding-separating device being of the type able to be assembled rotatable in correspondence with one end of said bobbin (12) and comprising a first thread-guide element (14) in which said first inner segment (11a) of yarn is able to pass, characterized in that said first thread-guide element (14) is supported by a circular element (16) able to be mounted coaxial with said bobbin

(12), said circular element (16) being provided with separation means (13) able to separate said first inner segment (11a) from said second outer segment (lib) of the yarn.

2 - Device as in claim 1, characterized in that said separation means comprise a ring (13) provided with an outer protection edge (15) able to allow said second outer ascending segment (lib) of the yarn (11), tensioned in the initial steps of the process, to slide without damage on said ring (13) and at the same time to allow free rotational movement to said circular element (16) . 3 - Device as in claim 1 or 2 , characterized in that said circular element (16) is able to allow an effective regulation (by grazing or fluid-dynamic friction or by magnetic braking) of the tension of said yarn (11) being worked, eliminating the friction contacts. 4 - Device as in any claim hereinbefore, characterized in that said circular element (16) has a conical, truncated cone, cylindrical or bell shape, with spokes, or any other shape able to allow it to rotate in a balanced manner. 5 - Device as in any claim hereinbefore, characterized in that said circular element (16) can consist of an assembly of several distinct parts or it can be made in a single piece. 6 - Device as in any claim hereinbefore, characterized in that sliding means (30) are provided to cooperate with fixed means (21, 23) associated with said bobbin (12) in order to facilitate, and if necessary to regulate, the rotational movement of said circular element (16) with respect to said fixed means (21, 23) .

7 - Device as in claim 6, characterized in that said sliding means (30) can be obtained in a single piece with said circular element (16) or can comprise one or more parts associated with said circular element (16) . 8 - Device as in claim 6, characterized in that said sliding means (30) comprise at least a wear element (36) located between a hub (31) integral with said circular element (16) and a fixed metal member (23) .

9 - Device as in claim 6, characterized in that said circular element (16) comprises a disk (18), parallel to said ring (13) and on which said sliding means (30) are assembled or made.

10 - Device as in claim 2, characterized in that said outer protection edge (15) comprises at least a circumferential segment (15a) made of a material with a low friction coefficient, and able to allow the reciprocal sliding of said yarn (11) on said ring (13) .

11 - Device as in claim 10, characterized in that said circumferential segment (15a) has a shape able to adapt to the zone of contact of said yarn (11) on said circular element (16) .

12 - Device as in claim 10, characterized in that said circumferential segment (15a) comprises a ring of any section (115) arranged on the peripheral circumference of said ring (13 ) .

13 - Device as in claim 10, characterized in that said circumferential segment (15a) comprises an additional surface element of anti-friction material.

14 - Device as in claim 1, characterized in that said thread-guide eyelet (14) is internally lined with or consists of material with a low friction coefficient.

15 - Device as in claim 9, characterized in that a second thread-guide eyelet (17) is assembled on said disk (18) in order to guide said first inner segment (11a) towards a threading eyelet (34) substantially coaxially with said bobbin (12) .

16 - Device as in claim 1, characterized in that said thread-guide eyelet (14) is able to carry said yarn (11) from inside to outside said circular element (16), in such a manner that said yarn (11) can be directed towards a threading eyelet (34) without having to pass in a second thread-guide eyelet (17). 17 - Device as in claim 15, characterized in that said second eyelet (17) is positioned not along the line of join between said first thread-guide eyelet (14) and said threading eyelet (34), but in a position tangentially more advanced such as to increase the tangential components of the actions of the yarn with respect to said circular element (16), thus facilitating the drawing thereof.

18 - Device as in claim 8, characterized in that said hub

(31) extends beyond the end of a fixed tube (32) and is provided along one outer wall with an aperture (39) able to allow said first segment (11a) to pass into said hub (31) , said first segment (11a) being able to then exit through a threading eyelet (34) located on the top of said hub (31) , so as to continue and form a balloon, so that said device is able to be used on a multiple twist twisting assembly. 19 - Device as in claim 8, characterized in that said wear element (36) comprises an abutment disk (36b) made of a low friction metal or sintered self-lubricating or comprising a fluid-dynamic sustentation system.