Method and device for connecting a plurality of threads, especially the ends of threads

Abstract

A method for connecting at least two threads, especially thread end regions, which are arranged overlapping and are connected together, wherein an auxiliary connection element is guided several times around the adjacent threads, the connection element remaining on the threads.

Description

The invention relates to a method for connecting ends of at least two threads, which especially are arranged with thread end regions overlapping and then connected together.

In textile technology the problem frequently arises that two threads must be connected together by their ends. For the lengthened thread thus produced, properties are strived for which, despite the connection point, come as close as possible to those of a one-piece thread of the same length. This particularly applies with regard to the strength and the thickness of the lengthened thread. The problem of manufacturing such thread connections is frequently made additionally difficult by the fact that the threads of an entire thread layer must be connected together with threads of another thread layer. The connections of the threads should be made at a speed and under conditions which allow industrial usage.

The individual threads of a layer frequently lie very close together whereby scarcely any space is available for handling the threads and making the individual connections. This situation is found for example when connecting an end of a warp thread layer such as are used in looms, to the beginning of a new warp thread layer. In order to connect the individual threads of the two thread layers together, conventionally respectively two thread ends are joined together by a knot. However, the knotting machines provided for mechanical production of knots require a relatively expensive and complicated mechanical structure. In addition, the knots are usually far thicker than the total of the diameters of the two threads. This can be problematical during the subsequent processing of the threads, for example, when pulling the connected threads through harness elements. Finally, there are also threads which are brittle under severe mechanical loading such as is the case during knot production. Such threads are almost impossible to connect together using knotting machines.

Another method for producing a connection has become known from EP 0 989 218 A1. Here it is proposed that the two thread ends should first be arranged next to one another such that they overlap, clamped in and then wound around one another in a helical fashion. The latter should be executed by means of a sleeve or two rollers which each rotate and additionally move along the threads. As a result of friction, in this case the two thread ends should be wound around one another. Then a liquid bonding agent should be applied to the thread ends thus prepared, with which the thread ends are fixed in the described position. However, this method has the disadvantage that these thread ends are subjected to very strong mechanical loading. This can be problematical especially with threads which consist of a plurality of filaments. This applies to threads which tend to break. In addition, the strength of the connection depends very predominantly on the adhesive force of the bonding agent. Finally, there is also the fear that the connection of one entire thread layer with threads of another thread layer takes a large amount of time and machine parts will be contaminated by the application of the bonding agent.

Finally, it is also already known to connect two thread ends together by splicing using air eddies. In this case, the filament connection of the threads is loosened in the region of the thread ends and filaments of the two thread ends are connected together by means of turbulence. However, this method has the disadvantage that only threads constructed as multi-filaments can be connected together by this method. Such a method is disclosed for example in DE-OS 28 10 741.

Finally, a method is known from DE 29 42 385 C2 wherein respectively two threads constructed as fibre bundles are bound by taking one or a plurality of fibres from one of the threads and winding these around the two threads. Thus, this method also can only be used with multi-filament threads. In addition, it has the disadvantage that fibres must be loosened from the bundle in a time-consuming fashion. In addition, the material of the two fibre bundles has a substantial influence on the strength of the connection.

Thus, the object of the invention is to provide a possibility for mechanical connection of threads, especially ends of threads which, despite a high tensile loading capacity, subjects the threads in the connection region to as little mechanical loading as possible. In addition, the connection region should have the smallest possible thickness so that a good further processing capacity of the connected threads is ensured. The method according to the invention should also be as universally applicable as possible, i.e., it should be suitable both for the connection of threads constructed as mono-filaments, as multi-filaments or as fibre composites. Finally it should be possible to produce the connection of the threads within a time which allows the method and an apparatus for producing the connection to be used economically.

The object is solved according to a first aspect of the invention by a method of the type specified initially by guiding an auxiliary element several times around adjacent thread end regions, said auxiliary element remaining on the threads.

According to a second aspect of the invention, the object is solved by a device for connecting ends of at least two threads, which is provided with a holding device for holding threads with their end regions overlapping, which has a connecting device with which the thread end regions arranged in the holding device are connected together in which an auxiliary element is guided several times around the thread end regions by the connecting device.

It is preferred to supply the auxiliary element to the threads in a gas or air stream. The same or one or a plurality of other air streams should then be used to wind the auxiliary element around the threads to be connected. The air flow should impart to the auxiliary element an at least substantially pre-determined direction of motion by which the auxiliary element moves around the threads. This preferably takes place by means of one or a plurality of air eddies running or directed around the thread ends.

The use of gas or air flows has the advantage that no moving parts are required either for supplying the auxiliary element or for producing the winding. A device for this purpose can have one or a plurality of air eddy chambers in which respectively one connection can be produced at the same time on the same threads. Such an embodiment is particularly cheap primarily because of the few, especially the few non-moving, components, and is additionally reliable against functional failure.

A preferred embodiment of a device according to the invention can provide a supply means with which the auxiliary element receives during its supply movement at least one movement component, which runs transverse to the alignment of the threads to be connected. A favourable arrangement of such a supply means can have a thread insertion nozzle with which the auxiliary element is supplied to the threads merely using compressed air. It can furthermore be advantageous if the auxiliary element also receives a movement component which runs parallel to that alignment of the threads to be connected which these acquire in the area of their connecting point. This movement component can be imparted to the auxiliary element already during its supply or only during an actual winding process in which the auxiliary element is then guided around the threads. Preferably used for the winding process is an air flow which moves helically around the threads as a result of the geometrical shape of an air eddy chamber and a direction of introduction of the air flow into the air eddy chamber.

In another favourable embodiment the device can have at least two chambers in which air eddies flow preferably independent of one another. The two chambers can be arranged directly next to one another and be separated from one another by a separating means. It has proved expedient if the air eddies are aligned in opposite directions in the chambers. This can be achieved by means of suitably oriented inlet channels for compressed air. In this case, both the direction of rotation of the air eddies and their longitudinal movement component can be oppositely directed in a direction parallel to the threads.

The invention is thus based on the idea that the end of one thread and the beginning of another thread should be arranged such they mutually overlap. In this case, the two overlapping thread end regions are preferably lightly tensioned and aligned substantially rectilinearly and parallel to one another. A windable, longitudinally extendable and preferably also bendable auxiliary element, such as a yarn, is guided several times around this overlapping region. In order that the properties of the connection can be influenced, the auxiliary element should not be an original component of the threads to be joined. The auxiliary element should thus also differ from the threads with regard to its material. According to the invention the auxiliary element can be supplied to the threads and then guided around them.

The guiding around the common circumference of the two thread end regions can be accomplished in different ways. In particular, as a result of the method being comparatively easy to implement, guiding around the auxiliary element in the form of a plurality of coils is preferred. These plurality of coils give a winding wherein the winding can have coils having the same and opposite directions of rotation and also a plurality of layers of coils arranged one on top of the other. Thus, the result of the guiding around of the auxiliary element according to the invention can be understood not only as a structure consisting of a yarn with a certain number of helical coils. The auxiliary element can be handled especially easily during the guiding around if it is preferably in a solid or in a transition state to a liquid state of aggregation.

In order that the finished connection can be subjected to tensile loading, the yarn itself can be under at least low tensile stressing during the production of the connection. Easy handling of the auxiliary element during production of the connection and despite this, a high loading capacity can advantageously be achieved if the tensile loading of the auxiliary element is increased after or before the end of the winding process and this tensile loading remains permanently on the auxiliary element. Among other things, for this reason a yarn which shrinks or contracts under certain actions such as heat or cold, for example, can be used as an auxiliary element. An example of yarns having such properties are yarns with at least one fraction of polyamide.

The elasticity of an auxiliary element can also be used to produce a connection. In this case, it can be provided that the auxiliary element under relatively high tensile stress is arranged around the two threads but initially at a distance from said threads. For this purpose the auxiliary element can also be arranged on spacers. If the spacers are then removed, the auxiliary element reaches the threads as a result of the tensile stress and its elasticity, and presses these threads together. Since in this case some of the tensile stress can be lost again, auxiliary elements, for example an elastic yarn with a suitably high elastic elongation, should be arranged on the spacer. Threads having the names Lycra (trademark of Dupont, Geneva, Switzerland) or Dorlastan (trademark of Bayer AG, Leverkusen, Germany) can be used as such an auxiliary connection element.

The tensile loading of the auxiliary element can result in the wound thread ends being pressed together. This pressure exerted on the thread ends is one of the factors responsible for the tensile loading capacity of the connection according to the invention. Any increase in the tensile loading of the auxiliary element can thus bring about an increase in the tensile loading capacity of the connection. At the same time, with higher tensile loading of the auxiliary element, the thread ends are pressed together more strongly which can again result in a smaller thickness of the finished connection. In addition, under higher tensile loading of the auxiliary element, said element presses into the thread end regions whereby a positive contact between the auxiliary element and the two thread end regions can additionally be produced. Frictional locking between the two threads to be joined can also contribute to the strength of the connection.

In order to bring about a further increase in the load-bearing capacity of the connection, it can be provided in an advantageous embodiment that an adhesive means is additionally applied. This adhesive or bonding means primarily has the purpose of strengthening the connection between said auxiliary elements and the thread end regions.

In a preferred embodiment it can be provided that the adhesive means is already contained in the auxiliary element itself. A first and especially preferred example for this are so-called combi fusible bonding yarns. Such yarns have two components. Whereas one component is a thin chemical fibre thread, the other component can be a fusion adhesive which develops its adhesive properties under heating. Polyamide-based combi fusible bonding yarns are especially preferred. With these yarns not only the adhesive fraction melts under heating in order to thereafter bind with the threads. Substantially at the same time as the melting process, the polyamide fraction also contracts and hereby produces in the yarn a tensile as well as a compressive force in the threads. On the one hand, as a result of the contraction a force-locking connection is produced and on the other hand, as a result of the adhesive means an adhesive and/or material-locking connection is achieved. Thus, the at least one heating process can be advantageously used in many respects. Such an adhesive connection can be permanently subjected to tensile loading and thus increases the tensile loading capacity of the connection originating from the winding.

Another example for the production of an adhesive connection can provide that the auxiliary element is covered with or impregnated with an adhesive during supply to the thread ends. During or after the winding of the auxiliary element around the thread ends, the adhesive can develop its adhesive effect by drying or hardening.

Further preferred embodiments of the invention are obtained from the claims.

The invention is explained in detail with reference to exemplary embodiments shown schematically in the drawings; in the figures:

FIG. 1 shows two thread layers to be connected;

FIG. 2 shows a device according to the invention for producing thread connections;

FIG. 3 shows an air eddy device according to the invention in two different end positions;

FIG. 4 a shows the air eddy device from FIGS. 3 and 4 viewed from above;

FIG. 5 shows a front view of a highly schematic air eddy device;

FIG. 6 shows a perspective view of a thread insertion nozzle;

FIG. 7 shows the thread insertion nozzle from FIG. 6 along the line VI-VI;

FIG. 8 shows a heating device according to the invention together with a holding/swivelling device which is shown in three different positions;

FIG. 9 shows a first exemplary embodiment of a connection according to the invention;

FIG. 10 shows a second exemplary embodiment of a connection according to the invention;

FIG. 11 shows the principle of action of a heating device according to the invention;

FIG. 12 a shows a section of a combi fusible bonding yarn in a highly magnified plan view;

FIG. 12 b shows a cross-section through a combi fusible bonding yarn;

FIG. 13 shows a perspective view of two halves of a shaft eddy body according to the invention;

FIG. 14 shows several instantaneous photographs during production of a connection in a shaft eddy body from FIG. 13;

FIG. 15 shows an alternative embodiment of an air eddy chamber together with a holding device for threads from warp thread layers;

FIG. 16 shows another device according to the invention for producing a connection;

FIG. 17 shows a mechanical winding device according to the invention for producing a connection.

FIG. 1 shows a highly schematic view of one end of a warp thread layer 1, shown in part, such as is used in looms. The warp threads 2 are tensioned in a frame 3. In order that the harness elements (not shown) retracted on warp threads 2 need not be retracted again, respectively one thread end 4 of a new warp thread layer 5 should be joined to the ends of the threads 2 of the end of the warp thread layer.

The device according to the invention shown in FIGS. 2 to 8 is provided to produce such thread connections. According to a highly schematic diagram in FIG. 2, this has an air eddy device 6 into which is fed a combi fusible bonding yarn 8 to be withdrawn from a yarn coil 7 and provided as an auxiliary connection element. In the exemplary embodiment shown the yarn having the trade name GRILON® C-85 (having a yarn strength of 2000 dtex) supplied by Ems-Chemie AG, Domat/Ems, Switzerland is used as the combi fusible bonding yarn. The combi fusible bonding yarn 8 is used to connect respectively one thread 2 of the thread layer 1 to one thread 4 of the new thread layer 5 (not shown in FIG. 2). For this purpose the two threads are arranged in the air eddy device 6 and the yarn 8 is wound around them, as will be explained in further detail subsequently. By means of a clamp 10 and a withdrawing device 11 arranged between the thread insertion nozzle 9, and the yarn coil 7, a yarn supply 14 can be made available to the thread insertion nozzle 9. The clamp 10 can also be used to limit a length of yarn injected into the air eddy device 6. The yarn 8 of a connection is separated from the coil 7 by means of a cutting device 15 arranged after the nozzle 9 in the direction of injection.

According to FIGS. 3 and 4, the air eddy device 6 is provided with an upper and a lower half 16, 17. Each of these halves 16, 17 has a substantially semi-cylindrical recess 18, 19. Both the radius and length of the semi-cylindrical recesses 18, 19 agree. A dividing wall 20 is arranged in each semi-cylindrical recess 18, 19 approximately at the centre with respect to its longitudinal elongation. In the representation in the figures, of the two dividing walls only the dividing wall 20 of the lower half 17 can be seen. The dividing walls 20 are aligned orthogonally to the longitudinal elongation of the semi-cylindrical recesses 18, 19. At their open ends the recesses 18, 19 taper conically to an essentially circular opening.

In an alternative embodiment the air eddy device could be constructed as one part. In this case, a slit should be incorporated in the tube wall in the longitudinal direction of the tubular air eddy device which makes it possible to insert threads from one of the sides.

In the lower half 17 respectively one through hole 55, 56 (FIGS. 4, 4a) is located in the wall of the half 17 on each side of the dividing wall 20. Each of the holes 55, 56 penetrates through the wall of the half 17. Both holes 55, 56 open approximately tangentially to the boundary surface of the semicircular cross-section recess 19 into the latter. The holes 55, 56 are used for intake of compressed air not shown in detail, with which an air eddy is produced on each side of the dividing walls 20. As a result of a pressure gradient, both compressed air eddies move approximately helically from the dividing walls towards the respectively open side of the two chambers 23, 24. Since the two chambers 23, 24 open on different sides into their respective chambers in relation to a longitudinal direction of the two chambers 23, 24, the two compressed air eddies have opposite directions of rotation.

In the lower half 17, two grooves 25, 26 which are flush with one another are incorporated in its wall 20 at an angle of for example approximately 0°-15° with respect to the plane dividing wall 20 (FIG. 4). As a result, one groove 25 lies on one side of the dividing wall 20 in one chamber 23 whilst the other groove 26 comes to lie on the other side of the dividing wall 20 in the other chamber 24.

The thread insertion nozzle 9 shown in further detail in FIGS. 6 and 7 is connected to the groove 26. As thread insertion nozzles, for example, it is possible to use those supplied by Te Strake Weaving Technology Division, PM Deurne, The Netherlands. Such a thread insertion nozzle 9 can have a casing 30 with an oblong hollow needle body 32 located at its front end. A nozzle body 31 is located behind the hollow needle body 32 in the casing. A cone 33 of the nozzle body 31 together with a funnel-shaped inlet 34 of the hollow needle body forms a gap 35. Its size can be varied by axial displacement of the nozzle body 31. Acceleration of air flowing into the gap 35 through a hole 36 in the casing and flowing out through a nozzle tip 38 can hereby by varied. For a purpose explained in greater detail subsequently, a yarn inserted through an axially running recess 37 in the nozzle body (not shown in the figures) can be entrained by the suction effect hereby produced and accelerated in the direction of the arrow 39 through the nozzle tip 38 and the hollow needle body 32. Such thread insertion nozzles 9 are previously known in another connection, for example, as weft feeders for looms.

The two halves 16, 17 of the air eddy chamber should be separable from one another for introduction of the threads to be connected. For this purpose in the embodiment shown in FIGS. 3 and 4 the upper half 16 is transferable into an upper and a lower end position by means of movement means not shown. In the upper end position the two halves have a spacing from one another through which two thread ends can easily be inserted between the two halves. This makes it possible for the two threads to be connected to be inserted axially parallel to the eddy chamber and the halves 16 can then be transferred back to their starting position.

As can especially be seen from FIG. 3, the two chamber halves of each chamber can be slightly offset with respect to one another. It can thereby be avoided that the air flow to be produced impacts on a longitudinal edge of the two halves during its circulation in the air eddy device. The slits 27, 28 required for insertion of the two threads can advantageously be closed before producing the connection so that an air eddy can flow as undisturbed as possible in the air eddy device. In a first embodiment, which is not shown however, for this purpose the two halves can rest against one another in the lower end position and for insertion and removal of the threads, one of the halves 16, 17 can be swung away or moved perpendicular to the longitudinal axis. In another embodiment shown in FIG. 5, closing elements 29 can be inserted in the gaps 27, 28. In order that the closing elements arranged in the chamber walls need only be provided on one side, it can be advantageous if the air eddy chamber is only slotted on one side.

In order to insert two adjacent threads in such an alternative air eddy chamber 23a slotted on one side, a holding device 45a can be provided as shown in FIG. 15. This has two warp yarn holders 48a, 49a displaceable perpendicular to the thread plane. The two warp yarn holders 48a, 49a arranged on a line with the slot 27a in the air eddy chamber 23a can thereby grasp the respective threads. As a result of the movement of the warp yarn holder, the threads are then inserted through the slot 27a into the air eddy chamber arranged between the two warp yarn holders and held there. In order to take out the threads, the warp yarn holder 48a, 49a must be lowered again. The threads then follow the movement of the warp yarn holder as a result of their elastic stress. In order to protect the connection, the eddy air can be switched off during extraction from the eddy chamber.

In order to insert and remove the thread ends between the two halves in FIGS. 3, 4, and 4a, a holding/swivelling device 45 can also be provided, as shown schematically in FIG. 8 in connection with a heating device 46 according to the invention whose purpose will be explained in greater detail subsequently. The holding/swivelling device 45 has two rocking levers 48, 49 affixed to a common swivel axis 47 whose free ends 48a, 49a are constructed as clamping holders for the two thread ends 50, 51. At least between the two clamping holders the two threads lie with their end regions adjacent to one another and on one another. As a result of a common swivel movement of the rocking levers 48, 49, the two clamped-in threads can be respectively inserted between the two halves 16, 17 (FIGS. 3 and 4) and guided out again.

The holding/swivelling device 45 can also be used to guide the thread ends, which continue to be clamped in, into the infrared heating device 46 shown in FIG. 8. Such a heating device can have an ellipse-shaped reflecting wall 52. In the direction of the longitudinal elongation of the threads 50, 51 the reflecting wall 52 should have a length which at least corresponds to the length of the respective coil 53 to be produced. A rod-shaped IR heating source 54 is arranged at one focal point of the ellipse. The clamped-in thread ends 50, 51 can be swivelled in at the other focal point and arranged there for a certain dwell time for a heating process. In FIG. 8 this is shown by dashed lines. For insertion of the thread ends 50, 51 the reflecting wall 52 can be provided with openings whose shape is matched to the transport path of the thread ends.

In order to connect two thread ends 50, 51 together, each thread should initially be inserted into the two clamping holders and fixed there. Such handling devices relating to the insertion of threads under stress are already known to the person skilled in the art from many areas of textile technology, for example, knotting machines. The holding/swivelling device 45 thereafter swivels the two threads between the two halves 16, 17 whereupon the upper half is lowered into its final working position. In this case, the threads are arranged between the halves 16, 17 and approximately along their common cylinder axis.

Thereafter, compressed air can be fed in both through the through holes 55, 56 opening into each chamber 23, 24 in the area of the dividing wall 20 (FIGS. 4, 4a) and also through the thread insertion nozzle 9. An air eddy flowing approximately helically towards the open end of the respective chamber is thereby produced in both chambers 23, 24. In addition a combi fusible bonding yarn 8 (FIG. 2) is sucked in through the thread insertion nozzle 9, accelerated in the nozzle, and inserted into the two grooves 25, 26 (FIGS. 3 and 4). A first part of the yarn inserted into the two grooves is thus located with its front end in the direction of insertion in the one chamber 23 whilst the remainder of the yarn 8 is located in the other chamber 24. The front end of the yarn is then grasped by the air eddy in the chamber 23, whereby this end rotates in the eddy about the two thread ends. Starting from the dividing wall 20 the yarn thereby winds itself helically around the two threads 50, 51 towards the open end of the chamber 23. As a result of the centrifugal force and the acceleration of the yarn 8 towards the end of the chamber, the rotating part of the yarn is in this case under tensile stress. This can have the result that with its winding movement the yarn presses the two thread ends towards one another.

The end of the fusible bonding yarn 8 used for the winding can in principle be fixed to the thread ends to be connected in various ways. If hot air is used for the air eddy, the yarn end of the combi fusible bonding yarn 8 may already be sufficiently melted on towards the end of the winding process to develop a sufficient bonding effect for the fixing. In the same way, it can be provided to locate a small nozzle at the end of the chamber with which hot air can merely be directed onto the end of the yarn. Finally, in one of further possible embodiments hot air can also be guided along the two threads 50, 51. This can very quickly bring not only the yarn end but also the entire yarn up to the temperature required to produce the bonding effect.

During the winding process of the yarn 8 in one chamber, the other end of the yarn can be released. The other half of the yarn can thereby be grasped by the air eddy of the other chamber 24. This air eddy rotates in a direction of rotation opposite to the air eddy of the first chamber 23 and with a longitudinal movement component opposite to this air eddy, running parallel to the threads, helically about the two threads. In the second chamber 24 the other end of the yarn is hereby wound around the thread ends in the direction of rotation of the air eddy of this chamber. This part coil also begins in the area of the dividing wall 20 and moves helically towards the open end of this second chamber 24. As a result of the opposite directions of rotation and longitudinal directions of motion of the part coils, a complete winding 53 is produced in which all the coils have the same direction of pitch as shown in FIG. 9. As shown in FIG. 9, by producing a winding in the double chamber from FIG. 3 at both coil ends the yarn coils can have a smaller pitch than at the centre of the winding 53. In an alternative production of a winding in a single chamber, in contrast only the last coils produced can have a smaller pitch (FIG. 10).

It can be postulated that the different pitches arise because in the course of the formation of each part winding, different yarn lengths and possibly different flow rates of the air eddies are present. With regard to magnitude and direction this can result in different forces acting on the yarn. This in turn can result in different pitches of the individual coils and different tensile stress in the yarn. From this it can be deduced that the geometrical shape of the air eddy chamber which influences the flow rate of the air eddy also influences the shape of the winding.

The threads now already connected can then be pulled laterally out from the air eddy or eddies by means of the holding/swivelling device 45 without there necessarily being any need to switch off the air eddies. If necessary, before removal of the threads 50, 51 wound with the yarn, the upper half 16 is transferred into its upper final position.

If heating of the fusible bonding yarn 8 is subsequently necessary, the threads can be inserted with a swivel movement of the holding/swivelling device 45 into the separate infrared heating device 46 show in FIGS. 8 and 11. The threads are arranged therein at a first elliptical focal point 71 and the IR heating source 54 located in the other elliptical focal point 69 is switched on. Direct IR radiation 70 and IR radiation 72 reflected by the reflecting wall 52 onto the elliptical focal point bring about a concentration of heat over the total length of the coil in the area of the thread ends 50, 51 which cause the combi fusible bonding yarn 8 to melt to a sufficient extend to produce an adhesive connection. The fusible adhesive of the combi fusible bonding yarn can naturally also be melted in a different fashion. In principle however, any form of contact and convection heat is suitable, for example hot air guided over the winding in the longitudinal direction of the threads 50, 51.

One or a plurality of carrier threads 74 generally consisting of polyamide of the combi fusible bonding yarn 8 shown in FIGS. 12a and 12b contract as a result of the action of heat, which results in force locking between the threads and the yarn. Without losing the shape of the winding, the molten adhesive from one or a plurality of fusible bonding threads 73 of the yarn 8 penetrates at least superficially into the threads 50, 51. The combi fusible bonding yarn 8 is hereby connected to the two thread ends 50, 51. This can be designated as material locking between the yarn 8 and the threads 50, 51. This also brings about fixing of the yarn onto the threads 50, 51, wherein an increase in the tensile loading capacity of the connection is additionally brought about by the solidification of the yarn. The thread ends can then be guided out of the heating device 46 if the yarn has been brought to its melting point. The solidification process can take place or be completed outside the heating device.

A connection between the two thread end regions is hereby made. Subsequently, other threads of a thread layer (for example of a warp thread layer) can be connected in the same way to the threads of another (warp) thread layer. Should this process take place very rapidly and in connection with a yarn sheet, cooling of each connection can also be provided after the heating process. Any sticking together of the connections can thus be avoided.

In other preferred embodiments another eddy technique can be provided to produce a winding around the thread ends. Thus, two halves of a shaft eddy body are shown in FIG. 13 which can be assembled by means of pins 78 and holes 79. A central recess 80 is provided between the two halves 76, 77. The two threads 50, 51 not shown in FIG. 13 are to be guided in through said recess. Around the recess 80 part of a shaft 81 which winds helically along the recess 80 is inserted in the shaft eddy body in each half. The shaft 81 thus has a shape similar to a spiral staircase. Unlike this however, one radius of the shaft decreases from one end of the recess to the other end. Radius is to be understood in this connection as the direction of extension of the shaft in a direction transverse to the longitudinal axis 82 of the recess.

At the end at which the shaft 81 has its largest radius, a combi fusible bonding yarn can be inserted into the shaft and compressed air can be fed in. For reasons of clarity said compressed air can merely be fed into the shaft 81 along indicated feeds 88. The compressed air flowing in the shaft entrains the combi fusible bonding yarn whereby the yarn moves in the shaft 81 towards the other end of the shaft and hereby winds around the two thread end regions 50, 51. This is shown highly schematically in FIG. 14 wherein the four instantaneous positions 83, 84, 85, 86 of the yarn indicated by the yarn ends correspond to four different instantaneous photographs of the same yarn during the winding process. A fifth instantaneous photograph shows the yarn end in its position 87 in the finished winding.

In another possible variant based on eddy technology, outlet openings 91 can be provided in an eddy body 90 in tubes arranged in a star shape with respect to one another. Such a device is shown in FIG. 16. The two threads 50, 51 to be connected are guided into the centre of the star by the device. The supplied compressed air then flows through all the outlet openings 91 such that the outflowing air has a tangential component.

The air eddies thereby produced again move helically around the thread ends 50, 51. A piece of yarn 8 extending from the thread ends initially transverse to these is then entrained by the air eddies and winds around the thread ends as a result of the air flows.

In another alternative embodiment the mechanical winding device 93 shown in FIG. 17 can be used to produce a winding. This can for example have a disk-shaped rotating body 94 slotted along a radius line. The rotating body 94 can for example be rotatably mounted in a bearing section with a rotating hollow shaft not shown in detail here. Provided on the rotating body 94 is a freely rotatable yarn coil 95 on which a yarn, for example, a combi fusible bonding yarn 8 is coiled. The thread ends 50, 51 to be connected are guided both through the slot 96 and through the hollow shaft. The rotating body should additionally be longitudinally displaceable in the direction of the longitudinal extension of the threads to produce the helical winding of the yarn 8.

In order to join the two thread ends together, the yarn end is arranged on the thread ends. The rotating body 94 is then set in rotary motion by a driving means not shown in detail here in a translational movement. The yarn 8 is hereby unwound from the coil body 95 rotating about the thread ends and is wound helically about the thread ends with a plurality of coils. The tensile stress in the yarn can be adjusted by means of a coil brake also not shown here. After a predetermined length of the thread ends has been wound, the yarn located on the thread ends can be separated from the coil body.

Claims

1. A method for connecting at least two threads, especially thread end regions, which are arranged overlapping and are connected together, wherein an auxiliary connection element is guided several times around the adjacent threads, the connection element remaining on the threads.

2. The method according to claim 1, wherein the auxiliary connection element is under tensile stress whilst it is guided around the threads.

3. The method according to claim 1, wherein whilst the auxiliary element is guided around the threads, the threads are aligned substantially rectilinearly.

4. The method according to claim 1, wherein the auxiliary element is wound around the threads in the form of coils.

5. The method according to claim 1, wherein a yarn, preferably a fusible bonding yarn or a combi fusible bonding yarn, is guided around the threads.

6. The method according to claim 1, wherein an additional material is applied to the threads, to produce material locking, especially an adhesive connection.

7. The method according to claim 6, wherein an adhesive is applied to the threads as additional material.

8. The method according to claim 6, wherein an auxiliary element which contains the additional material is wound around the threads.

9. The method according to claim 8, wherein the auxiliary element is heated during and/or after the winding around the threads to produce the connection.

10. The method according to claim 1, wherein the auxiliary element is wound around the threads using a gas, preferably air.

11. The method according to claim 10, wherein the threads are arranged in at least one chamber of an air eddy device and the auxiliary element is thereafter inserted into the at least one chamber of the air eddy device.

12. The method according to claim 11, wherein during insertion the auxiliary element has a direction of motion with a component which runs tangentially to the longitudinal elongation of the threads.

13. The method according to claim 11, wherein the auxiliary element is inserted into the chamber of the air eddy device using an air flow produced by a thread insertion nozzle.

14. The method according to claim 10, wherein the auxiliary element is grasped by flowing air, especially by an air eddy, and is guided around the threads.

15. The method according to claim 10, wherein the auxiliary element is wound in two different directions.

16. The method according to claim 15, wherein the first part length of the auxiliary element is inserted in a first chamber and wound around the threads in a first winding direction using a first air eddy and that a second part length of the auxiliary element is inserted in a second chamber of the air eddy device and is wound around the threads in a winding direction opposite to the first winding direction using a second air eddy.

17. A method for connecting the threads of a first warp thread layer with the threads of a second warp thread layer wherein respectively one thread of the first warp thread layer is arranged overlapping with respect to a thread of the second warp thread layer, wherein at least one thread of the first warp thread layer is connected to at least one thread of the second warp thread layer using one of the methods according to claim 1.

18. An apparatus for connecting ends of at least two threads which is provided with a holding device for holding overlapping threads, which has a connecting device with which the threads arranged in the holding device are connected together, wherein a helical coil of the auxiliary connection element around the threads can be produced with the connecting device.

19. The apparatus according to claim 18, wherein the auxiliary element is guided several times around the threads using the connecting device.

20. The apparatus according to claim 18, wherein the connecting device has a means for producing an air eddy flowing around the thread end regions with which the auxiliary element can be guided around the threads arranged in the holding device.

21. The apparatus according to claim 20, further comprising an air eddy device in which the thread end regions are arranged in at least one chamber, in the area of one end of the chamber compressed air can be introduced via an introduction means, said compressed air flowing around the thread end regions and towards the other end of the chamber as air eddies, and furthermore a means is provided for inserting an auxiliary element into the chamber and into the air eddy.

22. The apparatus according to claim 21, wherein the air eddy device has two chambers and compressed air to produce air eddies can be introduced into each of the two chambers.

23. The apparatus according to claim 22, wherein air eddies which flow in different directions of rotation about the thread ends can be produced using the introduction means of both chambers.

24. The apparatus according to claim 21, wherein the means for introducing an auxiliary element has a thread insertion nozzle.

25. The apparatus according to claim 18, further comprising an heating device with which the auxiliary element arranged on the thread end regions can be heated.

26. A device for connecting threads of a first thread layer with threads of a second thread layer comprising an apparatus according to claim 18.

27. A mechanically produced connection of at least two threads, wherein the connection is located in the thread end regions of the threads, where the threads overlap, wherein the thread end regions of the threads are jointly surrounded by a longitudinally extendable auxiliary element which is especially bendable in the load-free state but is under tensile stress in the connection.

28. The connection according to claim 27, wherein the auxiliary element is wound around the thread end regions in the form of a helical coil with a plurality of turns.

29. The connection according to claim 27, further comprising a material locking between the auxiliary element and the thread end regions.

30. The connection according to claim 27, wherein the auxiliary element is a yarn.

31. The connection according to claim 26, wherein the yarn is a fusible bonding yarn.