DEVICE AND PROCESS FOR THE HANDLING AND THE CONTROL OF THE THREAD ON A CONER MACHINE DURING THE OPERATIONS OF SPOOL CHANGE AND OF THREAD JOINING

Abstract: Device and process for the handling of the thread on a coner machine during the operations of spool change and of thread joining, where the thread route shows, from the spool to the cone, the sequence: - first cutting device (5) - pre-slub catcher (6) - thread feeler (7) - second cutting device (8) - thread tensioner (9) - suction and control nozzle (10) - thread joining unit (11) - slub catcher (12)

Description: The object of present invention is a device for the handling and the control of the thread on an automatic coning machine during the change of the feeding spool and/or of restoration of the continuity of the thread following thread breakage. The coning operation consists in transferring thread from a feeding spool to a cone wound up on a tube, detecting the defects of the thread and removing any faulty lengths from it, by cutting them and knotting the free ends thereof. The handling and control of the thread submitted to the coning is accomplished by means of various equipment pieces which the same thread meets according to a precise sequence along its route in the space, and which perform their action according to a sequence in time. In the prior art, many possible arrangements are reported for such equipment pieces, commonly denominated as the "thread route", in which both the composition of the set of equipment pieces which the thread meets when running along its route from the spool to the cone, and the sequential order according to which they are arranged, vary. The composition and the order of such sequence of pieces of equipment vary according to the productive choices, which tend to privilege some requirements of the operation, on the basis of different compromises between the various requirements. DE-A-2404035 discloses a device aiming at preventing that slack turns may be wound on the cone after a new start-up following a thread joining. Such a purpose is achieved by inserting along the thread route an auxiliary thread tensioner, interposed between the knotting device and the cone drive cylinder, which is actuated during the start-up step only. In such a way, the formation of a loop of thread inside the knotting device - which is responsible for the above said slack turns - is prevented. DE-A-2824752 discloses a device having the features of the preamble of claim 1. The known device aims at preventing that the slub catcher, after the breakage of the thread, may continue to detect the presence of the thread, by being occupied by a free end of the thread, or by a piece of the broken thread. In such case, the cycle of restoration of thread continuity is not begun. The suction nozzle arranged between the thread tensioner, on the same side of the spool, and the slub catcher, is movable substantially out of the plane of the thread path, and with an air stream moving out of the thread path. Such an air sucking nozzle is controlled by a travelling service trolley, and cooperates with a cutting device provided between the nozzle and the slub catcher, in order to remove the free thread end, or the thread length present inside the slub catcher. Such nozzle ends its task before the joining of the thread, and does not control the joined thread. In this known device, therefore, it is prevented that the slub catcher intervenes too seldom because of a presence of thread inside it. However, it may be that on resumption of the thread winding operation, loops may form on the joined thread or material like clots, flocks and dust may be taken up by the thread from the tensioner or other devices, and these loops or foreign material on entering the slub catcher may cause a new intervention thereof with a consequent new joining step, and this as many times as these irregularities occur. The present invention aims at avoiding that irregularities of the above kind cause a repeated need of intervention of the slub catcher and repeated need of joining the thread. This aim is achieved by a device as claimed in claim 1. The device according to the invention is schematically shown in a practical embodiment thereof in the accompanying drawings, wherein: Figures 1A and 1B respectively show a side view and a front view of the device; Figure 2 shows a part of the device in an operative step prior to joining; Figure 2A is a schematic representation of the end portion of the thread suction nozzle moving perpendicularly to the thread path; Figure 3 shows the device in the thread joining position; Figure 4 shows a schematic view of the thread suction nozzle bringing the joined thread to the normal winding position. The thread feeding spool 1, installed on a fixed, expandable pivot, not shown, supplies the thread 2, which unwinds according to a spiral commonly called "the balloon". The thread meets the balloon-breaker 3, which contains and limits the amplitude of the balloon, and then the thread guide 4, which defines exactly the position of the thread at the entrance to the thread guided route. Between the balloon-breaker 3 and the thread guide 4, a first cutting device 5 is interposed, which is symbolically indicated with a pair of scissors, but which can have a whatever configuration. The thread 2 finds then, along its upwards route, a pre-slub catcher 6, which is generally constituted by a slit of adjustable and preset size, for holding the clots or the coarsest imperfections, by tearing the thread. In this case, the point wherein the interruption of the thread occurs cannot be determined a priori , in that it necessarily occurs above the pre-slub catcher 6 due to the pulling by the upper winding-up device, and corresponds to the weakest portion of the overhanging thread. Its position, as well as the length of the free thread ends formed are hence whatever. The thread 2 meets - after the pre-slub catcher 6 - the thread feeler 7, which is constituted by a detector device for the thread presence. Said thread feeler 7 must "feel" the stationary thread at the beginning of the handling intervention cycle. In the absence of a thread, the requested intervention is that of spool change and of thread joining; in the presence of the thread, on the contrary, a joining intervention only is requested. The device 7 is hence that which determines the type of action to be undertaken, and hence the sequence of operations to be carried out. The thread 2 finds then, along its upwards run, a second cutting device 8, also here symbolically indicated by a pair of scissors. The thread 2 meets subsequently a thread tensioner device 9. Such thread tensioner device performs the function of giving the same thread a tension adjustable and ranging within preset limits, so to secure a regular cone winding up. The thread tensioner device 9 performs also the auxiliary function of eliminating the weak thread lengths. The thread tensioner device 9 can be embodied with one or more tensioning sections, generally constituted by pairs of coaxial washers opposite to each other and urged against each other. A thread tensioner device capable of maintaining such tension also in the presence of irregularities in the thread is described in EP-A-0 273 477. The thread tensioner device 9 is followed by the suction nozzle 10. Such suction nozzle is one of the basic components of the device, and performs the following functions: a) it catches the free thread end when the slub catcher 12 detects an irregularity in the thread and causes the cutting of the thread. It holds the free thread end and keeps it in a controlled position for the subsequent operations. During such step, the nozzle 10 intakes both the upper free thread end coming from the slub catcher 12, and a thread length coming from underneath the same nozzle 10, contained inside the tensioner device 9, which, subsequently to the action of the slub catcher opens; the nozzle 10 thus intakes also the dust, the clots and the flocks which have possibly accumulated inside the thread tensioner 9. Such an operation is described in detail hereunder, by referring to Figure 2; (b) it accompanies and positions the thread end coming from the spool 1, inside the thread joining unit or knotting device 11 which is installed just above the nozzle 10. Such function is disclosed hereunder, by referring to Figure 3; c) it accompanies and controls the thread after the joining, for it to take again its normal configuration. Such function is described in detail hereunder, by referring to Figure 4. The suction nozzle 10 is therefore subject to move in a direction perpendicular to the path of thread 2 in the plane of the path of the thread 2. The thread meets then the slub catcher 12. Such a slub catcher is one of the most important components of the coner machine, and its task is of detecting the defects of the thread 2 and of cutting the thread by means of a cutting device not shown in the drawings, but substantially positioned in the same position as the slub catcher 12. The thread 2 runs then upwards and meets a funnel-shaped member 13, which guides the same thread towards the thread guide slits 14 of the driving cylinder 15, which guide the turns of thread 2 on the cone 16. The device is completed by further handling devices and auxiliary devices. A thread catching suction nozzle 17 - the suction end of which is given an extended shape, so that it is able to perform its sucking action through the whole axial length of said cone - collects the free thread end from the cone side and, by moving about the centre 18, reciprocates between the end positions 19 of thread catching and 20 of thread consignment to the knotting device 11. A further thread catching suction nozzle 21 - which, for the sake of clearness in the drawings is shown in Figure 3 - collects the thread end from the side of the feeding spool 1 in an extreme position 22 lying between the first cutting device 5 and the pre-slub catcher 6, and, by rotating about the centre 23, takes the thread end to the position 24, for it to be consigned to the knotting device 11. Said suction nozzle 21 can - according to a preferred form of practical embodiment - be provided at its end portion with a catching cover, which holds the thread by clamping it between the cover and the nozzle edge. This contrivance secures a reliable catch also of short-length thread ends, which otherways would not be reliably caught by the suction effect alone, and allows furthermore economies to be accomplished in the suction. The devices which are in contact with the thread - such as, e.g., the slub catcher 12, the thread tensioner 9 and the thread feeler 7 - are maintained clean by means of pressurized air jets ejected from nozzles 25. The thread handling by the device according to the invention, which allows considerable advantages to be attained, is now disclosed. As already mentioned, the handling intervention is commanded by the slub catcher 12, which detects the absence of the thread. Such a thread absence can be caused by different circumstances: 1) the slub catcher 12 has detected a defect and has caused cut of the thread; 2) the thread tensioner 9 has caused removal of a weak point from the same thread; 3) the spool 1 contained coarse irregularities, stopped by the pre-slub catcher 6: the spool is faulty; 4) the spool is exhausted. In the first two cases, the matter is of only intervening to join the thread; in the latter two cases, the matter is of replacing the spool and joining the free thread end of the new spool with the free thread end of the cone. As soon as the slub catcher 12 signals the absence of the thread, the coning operation is discontinued. The cone 16 and the driving cylinder 15 are preferably moved apart from each other and independently braked, in order not to damage the already coned thread. When the braking is performed, the cone and the cylinder are approached each other again. The cycle of intervention according to the following sequence of operations is started. The thread feeler 7 closes on the thread and, should this latter be absent, actuates a control unit for controlling the spool 1 change, which is carried out simultaneously to the first steps of the thread joining or knotting cycle. If, on the contrary, the thread is present, the knotting cycle only is performed. After the thread feeling, the feeler 7 opens again. The spool change is generally automatically carried out by the same machine, which collects the new thread end and takes it to a position, on the thread route, from which it can be collected by the nozzle 21, by means of the action of devices not shown in the drawings. For the purpose of maintaining a high operation factor of the automatic coners, the faulty spools must be replaced, like the exhausted spools. They can be processed by means of lower-productivity machines. For a correct handling, it is essential that all of the residual thread lengths be removed. The nozzle 21 is placed in its position 22 already before the change of the spool 1. The cutting device 5 cuts the free thread end of the spool to be discharged, the possible thread length above the cutting device 5 is intaken by the nozzle 21 and is removed. After the cutting by the cutting device 5, the cutting device 8 arranged between the thread feeler 7 and the tensioner device 9 is actuated, both whether the thread is present, or not. As shown in the drawings, this cutting device 8 is located substantially intermediate the suction nozzle 10 and the lower thread catching position 22 of the nozzle 21. If the thread is present, the thread is subdivided into two lengths, the lower of which is removed by the nozzle 21, and the upper of which is intaken by the nozzle 10. The thread route from the spool 1 up to the slub catcher 12 is now free from thread residues. When the thread route is cleaned, the nozzle 21 is lifted according to the trajectory as shown by the short-dash line, to a position of non-interference for the change of the spool, and the presentation of the new free thread end. It then moves downwards for suction-collecting said new free thread end and holding it. Before bringing the lower thread end to the position 24, the thread end coming from the cone 16 is positioned inside the knotting device 11. This task is performed by the nozzle 17, which comes to the position 19 to collect said upper thread end from the cone 16, and then brings it to the position 20, as shown in Figure 3. The cylinder 15 is actuated to unwind the thread length necessary for that purpose. The nozzle 21 brings then the thread end of the new spool 1 to the position 24 according to the short-dash trajectory. According to a preferred form of practical embodiment, such route is run along in two lengths, in the presence of limited-length thread ends; along a first, lifting, length some thread turns are unwound from the spool 1; the nozzle 21 is then lowered again, so as to suck up again the unwound turns, to achieve a reliable hold, and the lifting up to position 24 is then carried out. Before the new thread end is brought to position 24, the suction nozzle 10 has performed the functions as disclosed under (a) above. They are now disclosed by referring to Figure 2, which shows a side view. The nozzle 10, shown in its normal position, after sucking up the thread ends and after the opening of the thread tensioner 9 and of the pre-slub catcher 6, moves to its outer position 10A, and with the suction being continued, it extracts any dust and flock clots possibly accumulated therein. When the nozzle 10 has come to its outer position 10A, the nozzle 21 leads the thread to the position 24. Now, the nozzle 10 moves back from its outer position 10A to the inner position 10B of Figures 3 and 4, meeting the new thread caught and held by the nozzle 21 and inserting it into the thread joining unit 11. The thread joining unit 11 can be constituted by a known mechanical knotting device, as well as by a known pneumatic or friction joining device, as required. In order to facilitate such operation, the hold of the lower thread end in the thread joining position is secured not only by the suction action, but also by an extension 26 of the nozzle 10, which projects axially from the nozzle 10 (Fig. 2A) at one side of the nozzle axis and leads the thread to the position 10B. The two thread ends are thus positioned inside the knotting device 11 and the knotting is carried out, with the nozzle 10 being kept in its position 10B. Before carrying out the joining, both the thread tensioner 9 and the pre-slub catcher 6 are closed again. When the knotting is ended, the thread is released from the knotting device 11, but such a release is accompanied by the nozzle 10, which controls it by means of its extension 26, moving gradually back from the position 10B to its normal position, and thus preventing loops from being formed. In any case, the return of the nozzle 10 from its position 10B does not occur before the coning is resumed. The thread joining or knotting process without spool change is now described. As disclosed above, in that case, the thread feeler 7 detects the presence of the thread 2 inside it and actuates a control unit for controlling a thread joining operation only. That means that the lower thread end - the thread end connected with the spool 1 - ends anyway above the same thread feeler 7, but in an indeterminate position. If the interruption is caused by the slub catcher 12, the thread end is however held by the nozzle 17; if, on the contrary, the interruption is due to a weak point interrupted by the thread tensioner 9, that situation may also not occur. The knotting cycle takes place exactly as disclosed above, with the difference that the thread caught by the nozzle 21 is not the thread of a new spool which was replaced, but is still the thread of the same spool. In that case, the cutting device 5 is kept inactive and the cutting operation is entrusted to the cutting device 8 only. The remaining operations of the cycle are those as already disclosed referring to the intervention of spool change. As it can be observed, the present invention provides for an arrangement of equipment pieces along a thread route, which accomplish thread handling and control which remove the residual lengths, remove dust and clots collected inside the components before the continuity of the thread being restored, and, when the thread continuity is restored, prevent thread loops from forming at process resumption, by means of a suction nozzle (10) which is moved transverse to the route of the thread in the plane of the route.

Claims: A device for handling and controlling the thread on an automatic coner machine during the change of the thread feeding spool (1) and/or the restoration of the thread continuity following a thread breakage, comprising sequentially, between the thread feeding spool (1) and the cone (16) being wound, a first cutting device (5), a pre-slub catcher (6), a thread feeler (7), a tensioning device (9), a suction nozzle (10) movable substantially perpendicularly to the thread path, a thread joining unit (11) and a slub catcher (12), characterised in that the device further comprises thread catching nozzles (17,21) for bringing the thread ends to be joined to said joining unit (11), in that between said thread feeler (7) and said tensioning device (9) there is provided a second cutting device (8), and in that said suction nozzle (10) is movable in the plane of the path of the thread (2) between an outer position (10A) wherein it cleans by suction said tensioning device (9) and said pre-slub catcher (6) and an inner position (10B) wherein it keeps in a thread joining position the thread (2) caught and held by one (21) of said thread catching nozzles (17,21). A device according to claim 1, characterised in that the suction nozzle (10) is provided with an extension (26) at its thread sucking end, said extension (26) projecting axially from the nozzle (10) at one side of the nozzle axis. A device according to claim 1, characterised in that said one (21) of said thread catching nozzles (17,21) is movable into a lower thread catching position (22) laying between said first cutting device (5) and said pre-slub catcher (6). A device according to claims 1 and 3, characterised in that said second cutting device (8) is located substantially intermediate said lower thread catching position (22) and said suction nozzle (10). A device according to claim 1, characterised in that said thread feeler (7) is operatively connected to a control unit for controlling a thread joining operation when the feeler (7) detects the presence of a broken thread (2), and for controlling a spool change and thread joining operation when the feeler (7) detects the absence of a thread (2).

Inventors: BADIALI, ROBERTO, COLLI, LUIGI
Applicants: SAVIO S.P.A.
Application year: 1988
Main classification: B65H69
IPC codes: B65H54, B65H69