EP0475484A1

EP0475484A1 - Device for making the tension of the thread uniform as it unwinds in a spooler

Info

Publication number: EP0475484A1
Application number: EP91202078A
Authority: EP
Inventors: Roberto Badiali; Amedeo Quaia
Original assignee: Savio SpA; Savio Macchine Tessili SpA
Current assignee: Savio SpA; Savio Macchine Tessili SpA
Priority date: 1990-08-29
Filing date: 1991-08-14
Publication date: 1992-03-18
Also published as: IT1243707B; IT9021329A0; IT9021329A1

Abstract

The present invention relates to a device for making the value of the tension of the thread uniform as it unwinds in a spooler, which is designed to wind thread at high speed, the said device comprising a movable element (1), which acts as an unwinding accelerator and which at the tip surrounds the axis of the cop and along the said axis descends and moves in an essentially concentric position, between the beginning and end of the cop, during unwinding of the wound thread, in order to ensure an essentially constant distance between the descending point of rewinding and the movable element above which, as stated, acts as an unwinding accelerator.

Description

The present invention relates to a device for making the unwinding tension of the thread uniform in a spooler, which is designed to wind thread at high speed unwinding it from a cop below and collecting it on a forming reel above.
Some textile working stages involve firstly transferring the thread, at the maximum speed possible, from one package to another. For example, a thread produced in a spinning machine, particularly in a continuous ring frame, is normally wound onto a spool or reel. The thread is then transported and supplied as a spinning cop for a rewinding stage. Spooling involves transferring (rewinding) from the starting cop to the collecting reel, with unravel unwinding, i.e. with axial extraction of the thread from the stationary cop. The starting package is often a cop coming from a ring spinner. Due to the mechanical limitations of a continuous ring frame, the spinning cops have a relatively small quantity of thread, up to a few hundred grams at most. Consequently, the said cops are rewound onto reels on which the quantity of thread and shape are suitable for use in a subsequent operation and incidentally the thread from several cops is collected in succession on a single reel. The purpose is always to obtain packages which are more suitable for the subsequent working stages such are dyeing, warping, inserting the weft, etc.
During these transfer operations, the thread may be improved by removing sections with defects of various types. With the continuous increase in the speed of such operations (expressed by the length of thread transferred in one unit of time) to reduce production costs, ever greater tension values in the thread are created and, therefore, more frequent breakages, which cause a considerable fall in the operating performance of the spooler and its productivity. Incidentally, breakage of the thread occurs under a tension which is greater than the thread's resistance to tensile stress. The thread on each spinning cop, which has been supplied at a set position of a spooler, is drawn upwards with a tension value which gradually increases between the beginning and the end of the spinning cop in the unwinding stage,as is well known to the textile dressers. Indeed, when the layer of thread on each spinning cop decreases as the winding operation of the spooler progresses, the layer of thread thus diminished twists only round the bottom end of the cop and the thread, drawn out of it, travels upwards twisting back round the surface of the cop. In this case, the angle of separation of the layer of thread decreases and therefore tension is applied to the travelling thread due to the friction between the lengths of thread, or the contact of the thread with the cop and this may lead to breakage of the thread. This phenomenon occurs more readily in spoolers with a high winding speed. In the more modern spoolers thread transfer speeds of 20-30 m/s are reached.
Furthermore, since the tension at the start of unwinding thread from a single spinning cop is low, the thread is wound onto the reel at a low tension and thus the layer of thread wound at low tension may be expanded outwards at one end side of the reel due to the pressure of the layer of thread on top of it. Since usually to obtain one reel several spinning cops are used, the expanded part appears within each set period thus causing the formation of a reel with faulty winding which may give rise to unacceptable production for subsequent working stages.
In such an operating process a device is required which adjusts the winding tension of the thread between the start and finish of the cop thus reducing the unwinding tension at the end of the supply cop.
Elements are known in the state of the art which by acting on the path of the thread in a fixed position guide it in precise unwinding forms which make it possible to limit the maximum tension values at which breakages of the winding thread frequently occur.
These known elements, which act as unwinding accelerators (balloon-breakers) have various geometrical forms, as is well known by those working within the field. However, in the best of cases they only lessen the phenomenon, but do not lead to an optimum result of uniformity in the unwinding tension between the start and finish of unwinding the thread from the supply cop.
Means of controlling the spooling speed, i.e. the winding speed, have also been proposed as a countermeasure to keep the thread tension at practically constant levels from the beginning to the end of the cop from which the thread has been unwound, as described in US Patent 4805846.
To obtain a thread tension which is approximately constant, in the said Patent the effect of the spooling speed on the thread tension is used. Indeed, by considerably reducing the spooling speed, in the interval of time in which the thread is unwound from the bottom part of the spinning cop, the tension is kept at a nearly uniform level for the entire duration of the spooling process. Such a solution will considerably reduce the operating performance of the spoolers in that for a certain interval of time the unwinding speed is considerably reduced and therefore a smaller quantity of thread will be transferred (wound on) in one unit of time. To all practical purposes this is unusable since it results in a considerable drop in the operating performance of the spooler and consequently in a reduction in its productivity. The aim of the present invention is to resolve the above-mentioned problems of the known state of the art by providing a device which ensures that the tension of the thread which is supplied in the spooler is kept at an essentially constant value during unwinding of the entire spinning cop and which offers the following advantages:

it can be applied for any type of thread be it fine, medium or thick;
it can be installed on existing spoolers;
it enables the thread at high transfer speed to assume a geometrical configuration of contained energy dissipation which is highly important in the above-mentioned known state-of-the-art applications

a movable element which acts as an unwinding accelerator and at the tip surrounds the axis of the cop and along the said axis slides and moves in an essentially concentric position between the beginning and end of the cop during unwinding of the wound thread; and the said movable element is essentially square in shape and also has a side slit for introduction of the thread which occurs each time the supply cop is replaced.
a kinematic mechanism which activates the said movement of the movable element along the axis of the unwinding cop, and the said kinematic mechanism is a rack which engages with a toothed pinion which is rotated by an electric step motor, the latter being activated so as to ensure an essentially constant distance between the descending point of rewinding from the beginning to the end of the cop from which the thread has been unwound and the movable element above which acts as an unwinding accelerator;
an element capable of detecting the axial unwinding position of the thread from the cop, i.e. the position of unwinding in progress until the end of rewinding the thread, and the said detection element is a photocell, or any known state-of-the-art optical sensor, made integral with a supporting frame common both to the movable element which acts as an unwinding accelerator and also to the electric step motor, the latter being activated and operated by electrical signals generated by the said photocell which detects from the beginning to the end of the unwinding cop the position of the point of rewinding of the thread.

The device that makes the value of the unwinding tension of the thread uniform in a spooler described in the present invention, takes concrete form, in its practical application, as a supporting frame common both to the movable element, which acts as an unwinding accelerator, and to the step motor as well as to the photocell and the said support slides and is guided along a rack shaft and the said shaft is essentially parallel to the axis of the unwinding cop.
The invention shall be described in detail below on the basis of the example of embodiment schematically represented in the drawings in the attached Figures, and additional details and characteristics shall be explained, in which connection it must be well understood that any variations in reciprocal positions of the elements and the consequent simplifications which could arise therefrom must be regarded as included in the protection requested as constructional variations covered by the general concept.
In the attached drawings:

Fig. 1 is an axonometric schematic view of the device covered by the present invention, showing also the path of the thread from the unwinding cop below up to the forming reel above and the said view shows the moment rewinding of the thread wound onto the cop supplied to the spooler begins;
Fig. 2 is an axonometric schematic view of the device covered by the present invention at the moment when the cop is full of wound thread and is therefore the moment when unwinding of the thread to transfer it to the reel above begins;
Fig. 3 is an axonometric schematic view of the device covered by the present invention at the moment when the cop has on its end part a limited accumulation of wound thread and is therefore the moment just before unwinding of the thread from the cop to transfer it to the reel above ends.

In the Figures the same elements bear the same reference numbers.
Furthermore, for the purpose of clarity of the invention as a whole, in the Figures the parts not necessary to understanding the invention, such as the operating and functional units along the path of the thread, the motorisation centre of the thread guide roller, the reel-carrier arm, the various supporting structures and the means of supply, support and cop removal , are omitted.
In the said attached Figures:
1 is the movable element quandrangular in shape which acts as an unwinding accelerator and in addition has a side slit for introducing the thread at each replacement of supply cop 3. Its position is essentially concentric and perpendicular to the axis of bobbin 23 and, therefore, to cop 3 of wound thread. The said element 1 is placed with its bottom edge, at the start of rewinding thread 4 from cop 3 full of wound thread, at a distance from the tip of bobbin 23 essentially fluctuating at around 20mm (in accordance with the experimental results of the proposer); 2 is a shaft fixed to support plate 21, the latter being fixed as a single body to the spooler frame (not illustrated). The said shaft 2 is formed in such a way that, along a section of its straight side, it has teeth to form a rack element 20; 3 is the cop of wound thread made in a ring spinner; 4 is the path, shown by a dotted and dashed line, of the thread which is unwound from cop 3 below and runs upwards to wind itself in crisscross coils around the forming reel 14; 5 is a supporting frame which slides axially along shaft 2. The said frame 5 supports in a fixed way and as a single body quadrangular element 1, motor 8 and also sensor 9 so that during its downward movement, shown by arrow 7, the said elements 1, 8 and 9 also move perfectly synchronized and to an identical extent; 8 is an electric step motor which activates and operates precise angular rotations of toothed pinion 18 which, by engaging with toothed rack 20, moves frame 5 and thus elements 1 and 9 up or down; 9 is a photocell, or any photoelectric element, capable of detecting in front the presence of the cone 24 of wound thread on the top part of cop 3. As the said cone 24 gradually descends, as rewinding of thread from cop 3 proceeds, the said photocell 9, detecting such descent sends, through wire 19, electrical signals which, in electronic board 16, will be amplified and processed in order to output from the said board 16 electrical signals which, through wire 15, are capable of activating limited angular rotations of motor 8 and, thus, of toothed pinion 18. The latter by engaging with rack 20 will gradually make supporting frame 5 descend as shown by arrow 7 so that photocell 9 constantly follows the lowering of the top cone of wound thread 24; 12 is the supply cylinder which rotates reel 14 and, imparting an alternating back-and-forth movement, guides the thread onto the said reel 14; 10 is the schematic side outline of the structure of a spooler; 14 is the reel which is a package of thread with a truncated cone shape, or a cylindrical shape, and the said package is produced by a spooler and intended for subsequent working stages (dyeing, warping, weaving, etc.); 23 is the thread winding bobbin, i.e. the support for the thread wound by the winding operation in a ring spinner to form a cop of yarn 3; 24 is the cone of wound thread and its truncated cone shape derives from the known method of winding the thread onto bobbin 23 on the spindle of a ring spinner. The operation of the device for making the value of the unwinding tension in a spooler uniform, illustrated by the attached drawings, can be easily understood by those working within the field.
A cop 3 full of wound thread is placed on the cop-holder pin (not shown) in the supply position. Its thread 4, using known means and devices, is brought to wind itself onto the forming reel 14 and rewinding of the thread begins, i.e. the transfer of thread 4 from cop 3 below to reel 14 above. The device covered by the present invention is stationary in the upper limit position (see Fig. 2). Photocell 9 detects in front the presence of the upper truncated shape of wound thread and quadrangular element 1 is positioned at a precise distance from the tip of bobbin 23. Thread 4, drawn upwards by supplier cylinder 12, on unwinding from cop 3, causes a gradual and continuous lowering of cone 24. This lowering will be detected by photocell 9 which, through electronic board 16, activates electric step motor 8.
The latter causes angular rotations of toothed pinion 18 forces, through rack 20, supporting frame 5 gradually to descend as shown by arrow 7 until it occupies the lower limit position as can be clearly seen in Figure 3. During this descent, photocell 9, motor 8 and quadrangular element 1 descend to an identical extent since they are integral and form one body with supporting frame 5. Movable quadrangular element 1 will always be at an essentially constant distance from the rewinding point of thread 4 from cop 3. Incidentally, the rewinding point of thread 4 from cop 3, i.e. the point at which thread 4 on unwinding becomes detatched and separates from cop 3, is localised exclusively in the restricted truncated cone band 24, as is well known by those working within the field. The said essentially constant distance between quadrangular element 1 and the rewinding point below during the entire unwinding of thread 4 from cop 3 results in a uniform constant value of the tension of thread 4 from the beginning to the end of cop 3, from which the thread is unwound to be transferred onto the above forming reel 14. In this way the tension of thread 4 is maintained at an essentially uniform value for the entire duration of the spooling process due to the operating presence of the device in question, which will consequently prevent most of the breakages of thread 4 during its transfer from cops 3 supplied to the reel 14.
All this enables extremely striking comparisons to be made particularly in the case of high-speed spoolers in which the speed of transfer of thread 4 from cop 3 to reel 14 is in the order of 2000 m/min and above.
Since the tension of the thread remains nearly uniform it is possible, as frequent accidental breakages do not occur, to obtain great improvements in the operating performance of spoolers and consequently in their productivity.
It is purely by way of example that a toothed pinion and rack transmission pair has been used since similar sliding pair mechanisms may be used capable of axially moving quadrangular-shaped element 1, which acts as an unwinding accelerator; furthermore, various modifications in detail may also be made to the form of supporting frame 5 and its method of fixing both to the element that detects the point of rewinding of the thread from the cop and also to the drive element without going beyond the scope of the invention.

Claims

A device for making the value of the unwinding tension uniform in a spooler, which is designed to wind thread at high speed unwinding it from a cop below which supplies thread to a forming reel above and the said device is 5 characterised in that it has:
- a movable element which acts as an unwinding accelerator and at the tip surrounds the axis of the cop and along the said axis descends and moves in an essentially concentric position between the beginning and end of the cop during unwinding of the wound thread;

- a kinematic mechanism which activates the said movement of the movable element along the axis of the unwinding cop;

- an element capable of detecting, moment by moment, the axial unwinding position of the thread from the cop, i.e. the position of unwinding in progress until the end of rewinding the thread which is transferring from the cop below to the reel above.
A device for making the value of the tension of the thread as it unwinds from the cop uniform in a spooler, according to Claim 1, characterised in that the element that acts as an unwinding accelerator, by containing and limiting centrifugation of the thread, is essentially quadrangular in shape and has a side slit for the introduction of thread which occurs each time the supply cop is replaced.
A device for making the value of the tension of the thread as it unwinds from the cop uniform in a spooler, according to Claim 1, characterised in that the kinematic mechanism which moves the said movable element along the axis of the cop is a rack which engages with a toothed pinion which is rotated by an electric step motor, the latter being activated so as to ensure an essentially constant distance between the descending point of rewinding from the beginning to the end of the cop from which the thread is wound and the movable element above, which acts as an unwinding accelerator.
A device for making the value of the tension of the thread as it unwinds from the cop uniform in a spooler, according to Claim 1, characterised in that the element that detects the axial position of unwinding of the thread from the cop is a photocell, or any optical sensor, made integral with the supporting frame common both to the movable element which acts as an unwinding accelerator and also to the electric step motor, the latter being activated and operated by electrical signals generated by the said photocell which detects from the beginning to the end of the unwinding cop the position of the point of rewinding of the thread.
A device for making the value of the tension of the thread as it unwinds from the cop uniform in a spooler, according to Claims 1 and 4, characterised in that the supporting frame common both to the movable element, which acts as an unwinding accelerator, and also to the electric step motor, as well as to the photocell, can slide along a rack shaft and the said shaft is essentially parallel to the axis of the unwinding cop.