GB2068033A - Thread splicing device - Google Patents

Abstract

A thread splicing device is provided with a splicing head 214 which comprises a splicing chamber having a longitudinal groove 222 for the insertion and connection of the threads, a compressed-air channel 213, which opens into the splicing chamber, and possibly a cover 224 for temporarily covering the longitudinal groove. The thread splicing device comprises a stationary basic body 212 with a channel 213, through which compressed air passes, and means e.g. screws 220, 221 to hold the splicing head to the basic body in an easily exchangeable manner. In this manner the thread splicing device can be quickly adjusted to effect splicing of different yarns, twists and threads. <IMAGE>

Description

SPECIFICATION Thread splicing device The invention relates to a thread splicing device with a splicing head which comprises a splicing chamber having a longitudinal groove, which may be coverable, for the insertion and connection of the threads, a compressed-air channel, which opens into the splicing chamber, and possibly a cover for temporarily covering the longitudinal groove.

A thread splicing device of this kind has become known, for example, through DE OS 2810741.

The possibility of using the known thread splicing devices is limited. It is not readily possible to use the same splicing head for the various threads and yarns, for example long-staple yarns and short-staple yarns, and for different yarn counts and yarn twists.

An object of the invention is to provide a thread splicing device which can be quickly adjusted to achieve effective splicing of different yarns, twists and threads.

According to the invention there is provided a thread splicing device with a splicing head which comprises a splicing chamber having a longitudinal groove, which may be coverable, for the insertion and connection of the threads, a compressed-air channel, which opens into the splicing chamber, and possibly a cover for temporarily covering the longitudinal groove, characterised in that the thread splicing device comprises a stationary basic body with a channel, through which compressed air passes, and a holding device for the splicing head, and in that the splicing head also has a holding device and is connected to the basic body in an easily exchangeable manner.

The advantages brought about with the invention consist particularly in that upon a batch change on the textile machine on which threads are to be spliced, the same thread splicing device can be optimally adjusted to the respective batch with a few manipuiations. A specific assortment of different splicing heads suffices for the maintenance of stocks. One does not require an assortment of different thread splicing devices.

Even splicing tests with unconventional thread material for the purpose of selecting the suitable splicing head can be rapidly and easily carried out.

Another advantage of the invention resides in ensuring that the shape, cross section, arrangement, covering and the ratio of the cross section of the longitudinal groove to the length of the longitudinal groove as well as the shape, cross section, arrangement, alignment, outlet of the compressed-air channel and the ratio of the cross section of the longitudinal groove to the cross section of the outlet of the compressed-air.

channel entering the longitudinal groove is optimally adapted to the diameter, the cross section, the volume, the number, the twist, the fibre type, the fibre length, the fibre structure, the surface structure of the fibres, the surface roughness of the fibres, the staple length, the surface structure of the thread, the thread roughness and/or the moisture content, the degree of the electrostatic charge, the size content, the foreign-body content of the threads to be joined.

The invention is developed, for example, in that the longitudinal groove has, at least in the groove bottom, a substantially circular cross section, which does not however form a full circle, a more or less large opening for inserting and removing the threads being left open. The diameter of the circle is larger for thicker yarns, a higher air pressure and a strong yarn or thread twist, a lower moisture content and an increased electrostatic charge of the thread.

In a further development of the invention, the cross section of the longitudinal groove has approximately rectilinear lateral boundaries above the circular groove bottom. These lateral boundaries may be arranged in parallel. They may also converge or diverge towards the top. Parallel or diverging lateral boundaries are particularly suitable for splicing very coarse yarns, for example for splicing carpet yarns or wool yarns and for spliciilg yarns having a large foreign-substance content. Converging lateral boundaries are particularly suitable for splicing cotton threads and considerably sized threads.

In a further development of the invention, the longitudinal groove has a substantially prismatic cross section with a flat groove bottom, the cross section being modified according to the conditions of the threads to be spliced.

In a further development of the invention, the longitudinal groove has a substantially rectangular or square cross section. In the case of the cross section being rectangular, the two long sides of the rectangle lie advantageously in the side walls.

However, it is also possible for the longitudinal groove to have a substantially trapezoidal cross section, one of the base lines of the trapezoid lying in the groove bottom.

There thus comes about an arrangement wherein either the shorter base line or the longer base line of the trapezoid lies in the groove bottom. In the first case, the longitudinal groove has diverging side faces; in the second case, it has converging side faces. The advantages of parallel, converging and diverging side faces have already been mentioned.

In a further development of the invention, the groove bottom has a substantially V-shaped or U-shaped groove which extends along the longitudinal groove. This groove has two functions to fulfil. On the one hand, its width may be such that it initially receives the threads to be spliced. In this connection, it is ensured that the threads lie closely side by side prior to the actual splicing process. However, the groove can also serve the purpose of distributing the splicing air in a better manner and of accelerating the threads to be spliced towards the cover. In order to fulfil this task, it is proposed in a further development of the invention that the compressed-air outlet should lie in the groove.

Effective splicing that is to say good intermixing of the fibres. is obtained if, in a further development of the invention, the lateral boundaries of the groove lie ap an angle of approximately 30 degrees to each other. With this dimensioning of the lateral boundaries, the compressed air emrnin in the groove bottom has an optimum fanning effect and, due to the inclined position of the lateral boundaries, the threads to be inserted er e brought into good contact with each other.

in a further development of the invention, it is proposed that the two end sections of the longitudinçl groove should have a larger cross section tan the centres section. The splicing head designed in -thls way is suitable for splicing both thin and thick threads. touring the insertion, the threads lie closely side by side in the central section. n general, the supply of air takes place here, too. The length of the central section depends again on the conditions of the threads.

Between the central section and the end sections, there may be provided a sudden or gradual cross-sec.;-rnal change. Both has its advantages for specific threads. For coarse yarns, a gradual cross-sectional change is preferred. For finer yarns, a sudden cross-sectional change can be advantagacus, oarticularly if, in a further development o. the invention, the enlarged cross section of the end sections extends towards the sides of the longitudinal groove.In this case, the actual, narrowly confined part of the groove bottom, on which part the threads lie, is not included in the cross-sectional eniargement. By contrast, when soarser yarns are spliced, it is of advantage if the enlarged cross section of the end sections extends towards the groove bottom or from the groove bottom.

An enlarged cross section of the end sections can also be brought about by rounding the edges of the longitudinal groove. Since a rounding of the edges also promotes the insertion of the threads and avoids damage thereto, it is advantageous if the edges of the longitudinal groove are rounded and smoothed. This applies to all the edges of the longitudinal groove.

Effective optimum spliced connections are obtained if, in a further development of the invention, the ratio of the longitudinal groove length to the NonSotudina! groove cross section is within the range of 0.5 to 1.0. This applies, for example, to the splicing of coarse yarns. For medium-fine e yrns, it is advan tageous if the ratio of the longitudinal groove length to the longitudinal groove cross section is within the range of 1.0 to 1.5.For very fine or coarsely twisted yarns, it is favourable if the ratio of the longitudinal groove length to the longitudinal grnove cross section is within the range of 2.5 to 4.0, in other words if to a groove length of respectively 2.5 to 4.0 mm there is allotted a groove cross section of 1 mm2. The fact that pretrence is given to these ranges does not however exclude the post-bility of measurement ratios outside or between these ranges being advantageous under special conditions.

In a further development of the invention, it is - proposed that the compressed-air channel situated in the splicing head should end in an air outlet nozzle which has a smaller free cross section and/or a cross-sectional form that differs from that of the compressed-air channel. At the transition into the air-outlet nozzle, there is thus in any event provided a point of unsteadiness which advantageously produces air vortices. If the free cross section of the air-outlet nozzle is smaller than the free cross section of the compressed-air channel, then the pressure drop in the compressed-air channel during splicing does not become apparent in such a very disturbing manner.

In a normal case, the longitudinal groove in the splicing head is symmetrically arranged. With this requirement, it is proposed, in a further development of the invention, that the compressed-air channel and/or .he air-outlet nozzle should be provided in the intersection of two planes of symmetry of the longitudinal groove. Both has its advantages. A compressed-air channel lying in the intersection of the planes of symmetry presents advantages in the external design and the exchangeability of the splicing head itself. An air-outlet nozzle lying in the intersection of the planes of symmetry distributes the air evenly and allows the air to emerge in an evenly distributed manner towards both ends of the longitudinal groove.

Advantageously, the longitudinal axis of the airoutlet nozzle is directed approximately tangentially towards one side wall of the longitudinal groove.

With such an orientation of the air-outlet nozzle, there is formed in the longitudinal groove an air vortex which facilitates splicing when twisted-up or short-stapled yarns, such as cotton yarns, are involved.

Another advantage of the invention lies in ensuring that the shape, cross section, arrangement and covering of the longitudinal groove harmonises with the configuration of the compressed-air inlet and that the shape, cross section, arrangement, orientation, outlet and the ratio of the cross section of the longitudinal groove to the cross section of the outlet of the compressed-air channel, which opens into the longitudinal groove, are optimally adapted to the diameter, cross section, volume, number, twist, type of fibre, fibre length, fibre structure, surface structure of the fibres, surface roughness of the fibres, staple length, surface structure of the thread, thread roughness and/or moisture content, degree of the electrostatic charge, sizing content, foreign-substance content of the threads to be joined and are in harmony with the air conduction.

In a further development of the invention, it is therefore proposed that the compressed-air channel should be connected to several air-outlet nozzles which open into the splicing chamber. This proposal opens up many possibilities for optimum splicing. On the one hand, one can bring about individual spliced connections by means of airoutlet nozzles which are distributed along the longitudinal groove at greater or lesser intervals.

On the other hand, if highly twisted yarns are involved, the yarn twist can be unravelled more fabourably by corresponding air vortices if, in a further development of the invention, the air outlet nozzles are arranged in a distributed manner to the left and right of the planes of symmetry passing through the length of the groove. For example, the compressed-air channel may be connected to two air-outlet nozzles, of which one is provided to the left and the other is provided to the right of the plane of symmetry passing through the length of the groove.

For example, the air-outlet nozzles may be directly opposite to one another. However, for splicing highly twisted yarns it is better if the airoutlet nozzles are also provided in a distributed manner to the left and right of the plane of symmetry passing transversely through the longitudinal groove. If, for example, two air-outlet nozzles are provided, then one air-outlet nozzle may be provided to the left of the plane of symmetry running across the longitudinal groove and the other air-outlet nozzle may be provided to the right thereof.

Advantageously, one of the air-outlet nozzles is provided in the intersection of the planes of symmetry. Such an arrangement has the special advantage that it is ensured that there passes into the splicing chamber, and the longitudinal groove respectively, an air jet which does not produce a rotating air vortex but penetrates the threads to be spliced centrally. The other air-outlet nozzles may be so provided that air vortices come about. If, for example, three air-outlet nozzles are provided, then, according to the last-mentioned specification, one air-outlet nozzle is provided in the intersection of the planes of symmetry, while the arrangement of the other two air-outlet nozzles is optional. They are put either also in the central section or advantageously in the end sections of the longitudinal groove.

In order to ensure that the air jet bundles emerging from the air-outlet nozzles do not have an unfavourable effect on one another, it is proposed in a further development of the invention that the central axes of the air-outlet nozzles should be parallel to the line of intersection of the planes of symmetry of the longitudinal groove.

In a further development of the invention, it is proposed that the compressed-air channel in the splicing head should have a free cross-sectional area which is larger than that of the air-outlet nozzles and/or that the cross-sectional shape of the air-outlet nozzles differs from that of the compressed-air channel. At the transition to the air-outlet nozzles, there is thus in any event provided a point of unsteadiness which advantageously causes air turbulences. If the free cross-sectional area of the air-outlet nozzle is smaller than the free cross-sectionas area of the compressed-air channel, then the pressure drop in the compressed-air channel during splicing does not become apparent in such a very disturbing manner.

It has already been mentioned above that a turbulent flow during splicing has advantages. In a further development of the invention, it is therefore proposed that the compressed-air channel should be provided with a turbulence producer. The turbulence producer may consist, for example, of an obstacle which traverses the compressed-air channel. Such an obstacle can be easily made and fitted. It may be a cotter pin or a channel insert. However, it is also possible for the turbulence producer to consist of macroscopic wall unevennesses. Experience has shown that wall unevennesses which are smaller than macroscopic ones do not lead to a sufficient turbulence. Advantageously, the wall unevennesses consist of a screw thread provided in the wall of the compresssd-air channel.Since the compressed-air channel mostly has a circular cross section, such a screw thread is easy to produce. The effectiveness of the wall unevennesses can be easily varied by the choice of pitch and depth of thread.

The ratio of the cross section of the longitudinal groove to the total cross section of the air-outlet nozzles greatly influences the effectiveness and the optimum success of splicing and the quality of the spliced connection In this connection, it is proposed in a further development of the invention that the ratio of the longitudinal groove cross section to the total cross section of the air-outlet nozzles should be in three selected ranges. One range is from ratio 1.4 to 3.0, the other range is from ratio 3.7 to 4.0 and the third range is from ratio 7.0 to 9.0. The first-mentioned range is favourable for large-volurne threads, woollen threads, carpet yarns and the like.The medium range of 3.7 to 4.0 is particularly suitable for single yarns and wool blended yarns; the range from 7.0 to 9.0 is particularly suitable for splicing cotton yarns and twisted-up yarns, particularly in conjunction with an arrangement of the air-outlet nozzles which is such that a swirling flow comes about.

However, in special cases, it may be advantageous to choose ratio ranges which are outside or between the mentioned ranges.

It has already been mentioned that the groove bottom may have a substantially V-shaped or U-shaped groove which extends alongside the longitudinal groove. The groove may, for example, serve the purpose of improving the distribution of the splicing air and of accelerating the threads to be spliced in the direction of the cover. In order to fulfil this function, it is proposed in a further development of the invention that at least one airoutlet nozzle should open into the groove if several air-outlet nozzles are provided.

In a further development of the invention, it is proposed that if the two end sections of the longitudinal groove have a larger cross section than the central section, the air-outlet nozzles are distributed over the central section and the end sections. A splicing head of such a design is suitable for splicing both thin and thick threads.

When being inserted, the threads lie closeiy one beside the other in the central section. In general, the supply of air is also effected in this section.

The length of the central section depends again on the conditions of the threads.

In a further development of the invention, it is proposed that thread guiding means and/or air guiding means shouid be provided at the ends of the longitudinal groove. These thread guiding means and/or air guiding means may consist, for example, of thread and air guiding plates which partially close the groove ends. However, it is also possible for the thread guiding means to consist of thread guides which project from the longitudinal groove.

The advantages of guiding means of this kind are obvious. With the cover opened, the threads can be rapidly and reliably placed into the longitudinal groove. During splicing, the air can be partly held in the splicing chamber or can be deflected in a favourable direction. All this promotes effective splicing.

In a further development of the invention, it is proposed that the air-outlet nozzle should be formed by a slot which is located in the plane of symmetry passing longitudinally through the longitudinal groove. This results in the advantage that the jet of air can penetrate centrally into the threads to be spliced at greater length but is nevertheless in a position of forming air vortices laterally. A slot-like air-outlet nozzle results in a longer and therefore more durable spliced connection and is suitable for threads having a high moisture content, a high sizing content and a high foreign-substance content.

In a further development of the invention, it is proposed that the splicing head should have an attachment bracket which projects into the basic body and through which the compressed-air channel passes. This presents various advantages.

On the one hand, the sealing between the basic body and the splicing head can be adequately brought about without any special sealing means by the labyrinth effect; on the other hand, the splicing head is firmly supported in the basic body.

Thirdly, the attachment bracket simultaneously serves as the compressed-air channel wall.

In order to prevent the splicing head from being twisted and in order to connect the splicing head quickly and reliably to the basic body and yet to maintain its easy exchangeability, it is proposed that the attachment bracket should have a cylindrical outer surface with a flattened portion and that the basic body should having a holding element which is directed towards the flattened portion. Such a holding element may be, for example, a fastening screw, whose end is directed towards the flattened portion of the attachment bracket. Differed. holding elements may be used, for example spring-loaded shift pins, spring-loaded pawls which are actuatable by hand or the like.

In the interests of effective splicing, attention also has to be paid to the interaction between the cover and the splicing head.

In order to prevent that a poorly dimensioned cover wrecks the good air guidance and optimum splicing action brought about by the invention, it is proposed in a further development of the invention that the cover, which temporarily covers the longitudinal groove during splicing, should project from the splicing head in the direction of the longitudinal groove and should have thread holddowns at its ends. The outflowing air flows against these thread hold-downs, and these thus directly influence the splicing operation. They furthermore serve for holding the threads or for limiting the thread movement during the splicing operation.To ensure that the air can flow with ease from the splicing head and, in doing so, simultaneously dampens the thread movement, it is furthermore proposed that the thread hold-downs should have air guiding surfaces which are obliquely directed towards the running direction of the threads to be spliced.

All in all, the invention puts the material into the expert's hand to design the splicing head in such a way that it is altogether optimally adapted to the diameter, cross section, volume, number, twist, type of fibre, fibre length, fibre structure, surface structure of the fibres, surface roughness of the :fibres, staple length, thread surface structure, thread roughness and/or moisture content, degree of the electrostatic charge, sizing content, toreign-substance content of the threads to be joined.

Exemplified embodiments of the invention are shown in the drawings. In the following passages, the invention will be explained and described in even greater detail with the aid of these exemplified embodiments. In the drawings: FIGURE 1 shows a section through a thread splicing device, of which FIGURE 2 shows a front view and FIGURE 3 shows a side view; FIGURE 4 shows a section through the same splicing device, the splicing head having however been rotated through 180 degrees; FIGURE 5 shows an elevation with a cut-away portion of a thread splicing device having a differently designed splicing chamber; FIGURE 6 shows this splicing device in a side view and in a partial section; FIGURES 7 and 8 show different ways of fastening the splicing head to the basic body; FIGURES 9 and 1Q again show different fastening possibilities; ; FIGURES 11 to 50 show further splicing heads.

In the first exemplified embodiment of the invention shown in the drawings of Figs. 1 to 3, one discerns of the thread splicing device, which is only shown in its essential details, a frame 211 which carries a basic body 212. The basic body 212 has an angled channel 213, 213', through which compressed air passes. The basic body 212 furthermore comprises a holding device for the splicing head 214, which device consists of a slug 215 and two threaded counterbores 216, 217.

The splicing head 214, too, has a holding device consisting of two straps 218, 219 and two countersunk screws 220,221 which engage in the threads of the counterbores 21 6, 21 7 and thus connect the splicing head 214 to the basic body 212 in an easily exchangeable manner. The splicing head 214 has a splicing chamber 222 consisting of a longitudinal groove. A compressedair channel 223, which is in communication with the compressed air carrying channel 213' in the basic body 212, opens into the splicing chamber 222. The splicing head 214 can be covered by a cover 224. The cover 224 is also provided with a longitudinal groove 225, so that the splicing chamber 222 altogether has a circular cross section when the cove is closed. The compressed-air channel 223 opens eccentrically into the thus formed splicing chamber 222.

The cover 224, too, has a holding device which herein consists of two threaded counterbores 226, 227. The cover 224 is held by a pivotable cover holder 228. The cover holder 228, too, has a holding device in the form of two bores 229, 230 which carry countersunk screws 231, 232 which, for their part, engage in the threads of the counterbores 226, 227 of the cover 224.

The vorticity direction of the compressed air flowing into the splicing chamber 222 can be changed by turning the splicing head. Accordingly, the exemplified embodiment of Fig. 4 shows the above-described device with the splicing head rotated through 180 degrees.

In the exemplified embodiment of the invention shown in the drawings of Figs. 5 and 6, the same basic body and the same cover holder are used as in the exemplified embodiment shown in the drawings of Figs. 1 to 3. However, the splicing head 214' used herein is differently designed. Its splicing chamber 222' has the shape of a prismatically cut longitudinal groove. Herein, the compressed-air channel 223' opens centrally into the splicing chamber 222'. The cover 224' has no longitudinal groove. It is connected to the cover holder 228 in the same way as in the exemplified embodiment shown in the drawings of Figs. 1 to 3.

Fig. 6 additionally shows the threads 233, 234 in readiness for splicing.

The splicing chamber 222' of this exemplified embodiment is suitable for long-staple yarns and twisted-up yarns, whereas the splicing chamber 222 of the preceding exemplified embodiments is more suitable for short-staple yarns. With a few manipulations, it is possible to exchange one splicing head for another and one cover for another cover.

The exchange of the splicing heads and the covers respectively is even easier if one chooses plug connections as the holding devices. For example, in the exemplified embodiment shown in the drawings of Figs. 7 and 8, the basic body 235 is connected to the splicing head 236 and the cover 237 is connected to the cover holder 238 by plug connections. Accordingly, the holding device of the basic body 235 consists of spring clips 239 and the holding device of the splicing head 236 consists of head pins 240. The holding device of the cover 237 also consists of head pins 241, and the holding device of the cover holder 238 consists of spring clips 242.

If one wants to exchange the splicing head 236, all one has to do is to withdraw it from the basic body 235 in the direction of the arrow 243.

The attachment occurs in the opposite direction, the springs clips engaging in the head pins.

The exemplified embodiment of the invention in the drawings of Figs. 9 and 10 shows another fastening possibility. Herein, the holding device of the basic body 235' consists of conical pins 244, 245, whose conicity is increased towards the outside. Two rows of such pins are provided, but in the drawing of Fig. 9 only one row with the two pins 244 and 245 is shown.

Herein, the holding device of the splicing head 236' consists of two dovetailed recesses 246, of which only one is visible. If one wants to exchange the splicing head 236', one has to withdraw it from the conical pins 244,245 in the direction of the arrow 247. The attachment occurs in the opposite direction.

In a similar manner, the holding device of the cover 237' consists of dovetailed recesses 248 and the holding device of the cover holder 238' consists of conical pins 249, 250.

As the holding device, there may serve, for example, engaging plug-in devices, such as bayonet fixings. In any event, the splicing head has to be so firmly connected to the basic body that it cannot unintentionally become loose or detached in operation. Another fastening possibility will be explained later.

Another device according to the invention is diagrammatically shown in two elevations and in a section in Figs.11,12 and 13 on the second drawing sheet.

The drawing sheets following thereafter respectively show different constructional forms of the invention in one, two or three views. For example, on the third drawing sheet, a splicing head is shown at the top in a perspective representation. At the bottom right-hand side, one discerns the same splicing head in a front view, and at the bottom left-hand side it is shown in a top view, the portion to the right of the centre line having been cut open. The representations of other exemplified embodiments are arranged in a similar manner.

In the exemplified embodiment of the invention shown in the drawings of Figs. 11 to 13, one discerns of the thread splicing device, which is only shown in its essential details, a frame 85 which carries a basic body 86. The basic body 86 has an angled channel 87, 87', through which compressed air passes. The basic body 86 furthermore comprises a holding device for a splicing head 201, which device consists of a slug 88 with a reception bore 89 and a holding element in the form of a fastening screw 90. The counterpart of this holding device is provided on the splicing head 201 in the form of a cylindrical attachment bracket 72 which has a flattened portion 91. towards which the holding element 90 is directed.

The splicing head 201 has a splicing chamber consisting of a longitudinal groove 14. A compressed-air channel 27 passes through the attachment bracket 72 to the vicinity of the longitudinal groove 14, where it ends in two airoutlet nozzles 92', 92". The air-outlet nozzles have altogether a free cross-sectional area which is smaller than that of the cylindrical compressed-air channel 27.

The spicing head 201 can be covered by a pivotable cover 109. The cover 109 has a smooth surface which is directed towards the longitudinal groove 14. Hovve-iar Sb a aiso has the choice of providing the cove. 109 with a longitudinal groove 110 which is mOre adapted to the cross-sectional shape of the longitudinal groove 14 of the splicing head 201.The CCiV9! 1 C3 iS fastened to a cover holder 113 by means of a holding device 111 with the interposition of a resilient plastics material plate 112.

One discerns in Fig. 13, in particular, that the cover 109, which temporarily covers the longitudinal groove 14 during the splicing of the threads 114, 115, overtops the splicing head 201 in the direction of the longitudinal groove 14 and has thread hold-downs 11 6, 11 7 at its ends. The thread hold-down 116 has an air guiding surface 118 and the thread ho!d-down 117 has an air guiding surface 119. The air guiding surfaces are directed obliquely towards the travel direction 120 of the threads 114, t 15 to be spliced which is indicated in a dash-dotted line.

In another exemplified embodiment of the invention, one discerns in Figs.14,15 and 16 a splicing head 2 with an attachment bracket 73 which in its dimensions is identical with the attachment bracket 72 of the preceding exemplified embodiment. The longitudinal groove 1 5 has in the groove bottom 40 a substantially circular cross section which has approximately rectilinear lateral boundaries 121, 122 above the circular groove bottom 40. The lateral boundaries 121.122 are opposite to each other in parallel.

One discerns in Fig. 1 6 that the compressed-air channel 28 is provided with a turbulence producer in the form of a screw thread 141. At its end, the compressed-air channel 28 merges in an air-outlet nozzle 142', whose cross section is not quite as large as that of the compressed-air channel and which has no wall vEnevennssses either.

In another exemplified embodiment shown in Figs. 17, 18 and 19, a splicing head 3 has an attachment bracket 74 similar to the preceding exemplified embodiment. Herein, the compressedair channel 29 merges in an air-outlet nozzle 93, whose free cross-sectional area is smaller than that of the compressed-air channel 29. The airoutlet nozzle 93 ends in the groove bottom 41 of the longitudina groove 1 6 which has a semicircular cross section.One discerns in the drawings of Figs. 8 and 9 that both the compressed-air channel 29 and the air-outlet nozzle 93 aie provide d at the Intersection of the plane of symmetry 142 passing longitudinally through the longitudinal groove 1 6 with the plane of symmetry 143 traversing the longitudinal groove. The two planes of symmetry are mutually perpendicular.

In another exemplified embodiment shown in Fig. 20, which is particularly suitable for particularly dry and electrostatically charged threads, one discerns a splicing head 4 with an attachment bracket 75. The longitudinal groove 1 7 has a circular cross section only in the groove bottom 42, which cross section ends above the groove bottom in approximately rectiiinear diverging lateral boundaries 123, 124. The free cross-sectional area of the compressed-air channel 30 is substantially larger than whe cross section of the air-outlet nozzle 94 which herein opens into the longitudinal groove 17 with a central axis 145 that is parallel to the central axis 144 of the compressed-air channel 30.

In another exemplified embodiment of the invention shown in Fig. 21, one discerns a splicing head 5 with an attachment bracket 76. Here, the longitudinal groove 1 8 forms, in a cross section, a circle which is not completely closed and which merges in rectilinear lateral boundaries 125,196 which in this case do not diverge but converge.

In this exemplified embodiment, the air guidance is special in that the compressed-air channel 31 passes through a channel piece 95' of reduced cross section into an air-outlet nozzle 95, whose central axis is directed approximately tangentially towards the opposite side wall of the longitudinal groove 18.

In this exemplified embodiment of the invention, the ratio of the longitudinal groove length to the longitudinal groove cross section is to be 0.6 and the ratio of the groove cross section to the air-outlet nozzle cross section is to be 8.9.

In another exemplified embodiment of the invention shown in Fig.22, the splicing head 6 has an attachment bracket 77. The longitudinal groove 19 is circular in cross section in the groove bottom and then changes into rectilinearly extending lateral boundaries 127,128 which are opposite to each other in parallel. Herein, the groove bottom has a substantially V-shaped groove 48 which extends along the longitudinal groove 1 9. The airoutlet nozzle 96 is directly located on the flat groove bottom of the groove 48 and accordingly has a slotted shape. The cross-sectional form of the air-outlet nozzle 96 thus differs from the circular cross-sectional form of the compressedair channel 32.

In this exemplified embodiment, the ratio of the length of the longitudinal groove to the cross section of the longitudinal groove is to be 0.9 and the ratio of the groove cross section to the airoutlet nozzle cross section is to be 1.4.

In a further exemplified embodiment, one discerns in the drawing of Fig. 23 a splicing head 7 with an attachment bracket 78. Here, too, the longitudinal groove 20 has in its groove bottom 43 a substantial!y circular cross section, which then changes into lateral boundaries 129, 130 which are rectilinear and opposite to each other in parallel.

From the groove bottom there extends a substantially U-shaped groove 49. In a partial zone, this groove 49 simultaneously forms a slotshaped air-outlet nozzle 97. Here, too, the airoutlet nozzle has a substantially smaller free cross-sectional area and furthermore a totally different cross-sectional shape from the compressed-air channel 33.

In a further exemplified embodiment of the invention, one discerns in the drawing of Fig. 24 a splicing head 8 with an attachment bracket 79.

The cross section of the longitudinal groove 21 is circular in the groove bottom and then changes into rectilinear and parallel lateral boundaries 131, 32. From the groove bottom there extends a substantially V-shaped groove 50 which has a flat bottom and whose lateral boundaries are at an angle of approximately 30 degrees to each other.

Here, too, the compressed air outlet is effected into the groove 50, namely through an air-outlet nozzle 98, whose cross section is substantially smaller than that of the compressed-air channel 34 which supplies the compressed air.

The ratio of the length of the longitudinal groove to the cross section of the longitudinal groove is to be 2.7 in this exemplified embodiment, and the ratio of the groove cross section to the air-outlet nozzle cross section is to be 2.3.

In a further exemplified embodiment of the invention shown in the drawings of Figs. 25, 26 and 27, the splicing head 10 comprises an attachment bracket 81. Herein, the longitudinal groove 23 has in the groove bottom an approximately semi-circular cross section which ends in short opposite end sections 135, 136.

Here, the groove bottom has a fairly large, substantially V-shaped groove 52, whose lateral boundaries 59, 60 are at an angle of approximately 30 degrees to each other.

Here, the air-outlet nozzle 100 is directly located on the bottom of the V-shaped groove 52.

One discerns in Fig. 26, in particular, that the free cross section of the air-outlet nozzle 100 is approximately only half as large as the free cross section of the compressed-air channel 36.

Here, the longitudinal groove 23 is divided into a central section 64 and two end sections 68, 69.

The end sections 68, 69 are continually widened towards the ends; by contrast, the transition between the central section and the end sections is sudden but not abrupt.

One discerns in the drawing of Fig. 27, in particular, that the enlarged cross section of the end sections 68, 69 extends from the groove bottom.

Related to the central section 64, the ratio of the length of the longitudinal groove to the cross section of the longitudinal groove is 0.9 in this exemplified embodiment and the ratio of the groove cross section to the air-outlet nozzle cross section is 1.4.

Another device according to the invention, which is similar to the device shown in Figs. 11, 12 and 13, is diagrammatically shown in Fig. 28.

In the exemplified embodiment of the invention shown in Fig. 28, one discerns of the thread splicing device, of which only inipontant I components are shown, a frame 85 which carries a basic body 86. The basic body 86 has an angled channel 87, 87', through which compressed air passes. The basic body 86 furthermore comprises a holding device for a splicing head 1 50, which device consists of a slug 88 with a reception bore 89 and a holding element in the shape of a fastening screw 9Q. The counterpart of this holding device is provided on the splicing head 1 50 in the form of a cylindrical attachment bracket 72 which has a flat 91, against which the holding element 90 is directed.

The splicing head 150 has a splicing chamber.

A compressed-air channel 1 63 passes through the attachment bracket 72 as far as the vicinity of the longitudinal groove 14', which has a rectangular cross section, where it ends in an air-outlet nozzle 92'. The free cross section of the air-outlet nozzle 92' is smaller than that of the cylindrical compressed-air channel 1 63. The air-outlet nozzle 92' also has a different cross-sectional shape; it is slot-like.

The splicing head 1 50 can be covered by a pivotable cover 109. The cover 109 has a smooth surface which is directed towards the longitudinal groove 14'. However, one also has the choice of providing the cover 109 with a longitudinal groove 110 which is better adapted to the cross-sectional shape of the longitudinal groove 14' of the splicing head 1 50. The cover 109 is fastened to a cover holder 113 by means of a holding device 111, a resilient plastics material plate 112 being positioned therebetween.

The following drawing sheets show different constructional forms of the invention in one, two or three views. At the top of the next drawing sheet there is shown a splicing head in a perspective representation. One discerns the same splicing head in a front view at the bottom right hand side and in a top view of the bottom left hand side, the portion located to the right of the central line being cut open. The other representations are of a similar design.

In another exemplified embodiment, one discerns in Figs. 29,30 and 31 a splicing head 1 51 with an attachment bracket 1 70, which in its dimensions is identical with the attachment bracket 72 of the preceding exemplified embodiment. The longitudinal groove 1 57 has a trapezoidal cross section. Fig. 30 shows a detail of Fig. 31 taken along the line A.

One discerns in Fig. 31 that the compressed-air channel 1 64 is provided with a turbulence producer in the shape of an obstacle 1 76 which extends across the compressed-air channel. At its end, the compressed-air channel 1 64 changes into an air-outlet nozzle 177, whose free cross section is not as large as that of the compressed air channel 1 64.

In another exemplified embodiment, shown in Fig. 32, a splicing head 162 comprises an attachment bracket 171 similar to the preceding exemplified embodiments. Here, the compressed-air channel 165 merges in an airoutlet nozzle 1 78, whose free cross section is smaller than that of the compressed-air channel 165. The air-outlet nozzle 178 ends in the groove bottom of the longitudinal groove 158. The longitudinal groove 158 is asymmetric.

In another exemplified embodiment shown in Fig. 33, one discerns a splicing head 153 with an attachment bracket 172. The longitudinal groove 1 59 has a trapezoidal cross section, whose lateral boundaries are diverging. The free cross section of the compressed-air channel 1 66 is substantially larger than the slot-shaped cross section of the air-outlet nozzle I 79.

One discerns n the compressed-air channel 166 a turbulence producer in the shape of a screw thread 183. The lateral boundaries of the longitudinal groove 159 form an angle of 30 degrees.

In another exemplified embodiment of the invention, shown in Fig. 34, one discerns a splicing head 154 with an attachment bracket 173. Here, the longitudinal groove 160 forms in cross section a trapezium, whose longer base line is located in the groove bottom so that the lateral boundaries do not diverge but converge in this case.

The groove bottom has herein a substantially V-shaped groove 184 which extends along the longitudinal groove 160. The air-outlet nozzle 180 is situated directly on the flat groove bottom of the groove 184 and is therefore slot-shaped. Thus, the cross-sectional shape of the air-outlet nozzle 1 80 differs here, too, from the circular cross-sectional shape of the compressed-air channel 167. The lateral boundaries 185,186 of the groove 184 are at an angle of 30 degrees to each other.

In this exemplified embodiment, the ratio of the length of the longitudinal groove to the cross section od the longitudinal groove is to be 1.3 and the ratio of the groove cross section to the airoutlet nozzle cross section is to be 3.7.

In another exemplified embodiment of the invention, one discerns in Figs. 35, 36 and 37 that the splicing head 156 has an attachment bracket 175. Here, too, the longitudinal groove 162 is trapezoidal in cross section and ends, with its groove bottom, in the compressed-air channel 1 69. Here, too, this results in a slot-like air-outlet nozzle 182.

In this exemplified embodiment, too, there are provided thread guiding means in the shape of thread guides 190 to 193 which project from the longitudinal groove 162. The thread guides cooperate in pairs.

The associated cover, which is not shown herein, in this case does not project from the splicing chamber in the direction of the longitudinal groove 162 but projects transversely thereto.

In all the exemplified embodiments shown so far, the edges OT the longitudinal grooves are to be rounded and smoothed. This is specially pointed out because this fact is not readily discernible from the representations shown in the drawings.

In another exemplified embodiment of the invention, one discerns in the drawings of Figs. 38, 39 and 40 a splicing head 9 with an attachment bracket 80. Here, the cross section of the longitudinal groove 22 is approximately semicircular in the groove bottom 44 and then changes into rectilinear parallel lateral boundaries 133, 134. The groove bottom 44 has a substantially U-shaped groove 51 which extends along the longitudinal groove 22.

As shown in Fig. 39, the longitudinal groove 22 is divided into three sections, namely a central section 63 and two end sections 66, 67. The two end sections have a larger cross section than the central section, and the enlarged cross section of the end sections 66, 67 extends with a gradual cross-sectional enlargement from the groove bottom 44 towards the bottom of the groove 51, which bottom is then reached by the two end sections right at the end.

The two air-outlet nozzles 99' and 99" extend from the compressed-air channel 35 to the groove 51. The groove 51 projects into the air-outlet nozzles. This results in a slot-like cross-sectional shape of the air-outlet nozzles, which also allows the air to emerge laterally.

In this exemplified embodiment, the ratio of the groove cross section to the air-outlet nozzle cross section, related to the central section 63, is 3.0.

Another exemplified embodiment of the invention is shown in the drawings of Figs. 41 and 42. Herein, the splicing head 11 has an attachment bracket 82. The longitudinal groove 24 is circular in cross section, but the circle is not closed. The symmetrical longitudinal groove 24 has two preferred planes of symmetry 146, 147 which are perpendicular to each other.

In this exemplified embodiment, there are provided two air-outlet nozzles 101, 102 Both open into the groove bottom 45. The drawing of Fig. 42 reveals that the air-outlet nozzle 101 is provided to the left of the plane of symmetry 146, which passes through the length of the groove 24, and the air-outlet nozzle 102 is provided to the right thereof. The drawing of Fig. 41 reveals that the air-outlet nozzle 101 is provided beneath the plane of symmetry 147, which extends across the.

longitudinal groove 24, and the air-outlet nozzle 102 is provided above this plane.

This special arrangement of the air-outlet nozzles is particularly suitable for threads which have a Z twist. If, by contrast, the air-outlet nozzle 102 is provided on the left-hand side at the top and the air-outlet nozzle 101 is provided on the righthand side at the bottom, related to the representation of Fig. 41, then this arrangement is more suitable for threads provided with an S twist.

The drawings reveal that the total cross section of the air-outlet nozzles is súbstantially smaller than the free cross-sectional area of the compressed-air channel 37, which comprises a turbulence producer in the shape of a screw thread 202.

Another exemplified embodiment of the invention is shown in the drawings of Figs. 43 and 44. Herein, the splicing head 12 has an attachment bracket 83. The longitudinal groove 25 has in the groove bottom an approximately semi-circular cross section which changes into parallel lateral sections 1 37, 138. From the groove bottom, there extends a groove 53, whose lateral boundaries 61,62 are at an angle of approximately 30 degrees to each other. Here, the groove 53 does not project into the compressedair channel 38.

Three air-outlet nozzles 103, 104 and 105 are provided. The air-outlet nozzle 105 is centrally arranged and ends centrally in the groove 53. Its free cross-sectional area is larger than that of the two other air-outlet nozzles 103 and 104 which are provided similar to the preceding exemplified embodiment.

The nozzle arrangement chosen has the advantage that primarily a centrally directed flow is imparted to the threads to be spliced and that, in addition, limited swirling flows are imparted to the threads and are brought into the splicing chamber in support of the central flow.

Another exemplified embodiment of the invention is shown in the drawings of Figs. 45, 46 and 47. Herein, the splicing head 13 has an attachment bracket 84, through which a compressed-air channel 39 passes, as in the other exemplified embodiments.

The splicing head 13 has several special features which in total have the effect that this splicing head can be used somewhat more universally. The longitudinal groove 26 is in the groove bottom 46 approximately semi-circular in cross section, but then changes towards the outside into short, straight, parallel lateral boundaries 139, 140.

In this exemplified embodiment, the longitudinal groove 26 is divided into three sections which are approximately equal in length, namely a central section 65 and two end sections 70, 71. In the central section 65, one discerns a groove 54 which starts in the groove bottom 46 and which is substantially U-shaped in cross section. For the rest, the cross-sectional shape of the end sections 70 and 71 is similar to the crosssectional shape of the central section apart from the fact that the end sections have no groove.

The cross section of the two end sections is larger than the cross section of the central section.

The cross-sectional change is sudden. The enlarged cross section of the end sections extends both towards the sides of the longitudinal groove and from the groove bottom of the longitudinal groove.

There are provided three air-outlet nozzles 106, 107, 1 08. As one can easily see, the air-outlet nozzle 108 lies in the line of intersection of the plane of symmetry which extends lengthwise through the longitudinal groove with the plane of symmetry which is perpendicular thereto. The airoutlet nozzle 106 is in the end section 71 and the air-outlet nozzle 107 is in the end section 70, located respectively to the left and right of the plane of symmetry extending lengthwise through the longitudinal slot.

The air-outlet nozzle 108 ends centrally in the compressed-air channel 39. The air-outlet nozzle 106 is connected through a small transverse channel 148 to the compressed-air channel 39 and the air-outlet nozzle 107 is connected thereto through a small transverse channel 149, as shown in Fig. 45 in particular.

The air-outlet nozzle 108 lies in the longitudinal axis oj the compressed-air channel 39. The central axes of the air-outlet nozzles 106 and 107 are parallel to the central axis of the compressed-air channel 39.

In this exemplified embodiment, the air-outlet nozzles are considerably farther apart than they are in the preceding exemplified embodiment.

The splicing head 13 is particularly suitable for splicing thin and highly twisted threads and for splicing threads of special sensitivity. l However, its range of application also extends to coarser threads This exemplified embodiment of the invention is again particularly suitable for Z twisted threads.

For S twisted threads, the air-outlet nozzle 106 may be displaced to the right dnd the air-outlet nozzle 107 may be displaced to the left, related to the representation of Fig. 46.

In the last exemplified embodiment of the invention shown in the drawings of Figs. 48, 49 and 50, one discerns a splicing head 1 55 with an attachment bracket 1 74. Here, too, the longitudinal groove 161 has a cross section in the form of a trapezium, whose shorter base line forms the groove bottom. The compressed-air channel 1 68 ends in the air-outlet nozzles 181' and 181".

At the ends of the longitudinal groove 161 there are provided thread and air guiding means in the form of thread and air guiding plates 187, 188. The air guiding plates are fastened to the front ends of the splicing head 1 55 by means of spring pins 1 89 and are therefore adjustable in their covering effect. One discerns in the drawings that the thread and air guiding plates partially cover the longitudinal groove 161, but only to such an extent that the thread guidance is not obstructed.

Voluminous threads, hairy threads, electrostatically charged threads and particularly dry threads can be easily spliced with devices shown in Figs. 20,21,22,25 to 27,32, 34,41 and 42. Fine threads, highly twisted threads, sized threads or moist threads can be spliced more easily with devices shown in Figs. 23 and 24, 28, 29to31,38 to 40, 43 and 44,45 to 47.The devices shown in Figs. 34, 35 to 37, 45 to 47, 48 to 50 can be used more universally both for fine, thin threads and for voluminous threads consisting of cotton, wool or mixtures with synthetic fibres.

In the exemplified embodiment shown in Figs. 48 to 50, the adjustability of the thread and air guiding plates 187, 188 also is of advantage.

In all of the exemplified embodiments, the edges of the longitudinal groove are to be rounded and smoothed. This is pointed out in particular because this fact does not readily emerge from the representations shown in the drawings.

The invention is not confined to the exemplified embodiments shown and described All the features of the exemplified embodiments described and shown can be optionally exchanged for and combined with one another.

Claims (44)

1. A thread splicing device with a splicing head which comprises a splicing chamber having a longitudinal groove, which may be coverable, for the insertion and connection of the threads, a compressed-air channel, which opens into the splicing chamber, and possibly a cover for temporarily covering the longitudinal groove, characterised in that the thread splicing device comprises a stationary basic body (12, 35, 35') with a channel (1 3, 13'), through which compressed-air passes, and a holding device for the splicing head (14; 14', 36,38), and in that the splicing head (14, 14', 36,36') also has a holding device and is connected to the basic body (12,35, 35') in an easily exchangeable manner.

2. A thread splicing device as claimed in Claim 1 , characterised in that the cover (24, 24', 37, 37') is fastened in an easily exchangeable manner to a movable cover holder (28, 38, 38') by means of a holding device.

3. A thread splicing device as claimed in Claim 1 or 2, characterised in that the longitudinal groove (14 to 26} has, at least in the groove bottom (40 to 46), a substantially circular cross section, which does not however form a full circle, there being left open an opening of greater or lesser size for the insertion and removal of the threads (114,115).

4. A thread splicing device as claimed in Claim 3, characterised in that the cross section of the longitudinal groove (15, 17 to 23, 25, 26) has approximately rectilinear lateral boundaries (121 to 140) above the circular groove bottom (40, 42, 43,44,46).

5. A thread splicing device as claimed in Claim 1 or 2, characterised in that the longitudinal groove (14,157 to 162) has a substantially prismatic cross section with a flat groove bottom, the cross section being modified according to the conditions of the threads to be spliced.

6. A thread splicing device as claimed in Claim 5, characterised in that the longitudinal groove (14') has a substantially rectangular or square cross section.

7. A thread splicing device as claimed in Claim 6, characterised in that the two long sides of the rectangle lie in the side walls of the longitudinal groove f14'i.

8. Athread splicing device as claimed in Claim 5, character,sed in that the longitudinal groove (1 60) has a substantially trapezoidal cross section, the longer base line of the trapezium lying in the groove ooitorr..

9. A thread splicing device as claimed in Claim 5, characterised in that the longitudinal groove (157,158,159,161,162) has a substantially trapezoidal cross section, the shorter.

base line of the trapezium lying in the groove bottom.

10. A thread splicing device as claimed in one of Claims 1 to 9, characterised in that the groove bottom (43, 44, 46) of the longitudinal groove (14, 19 to 23,25,26, 160) has a substantially Vshaped or U-shaped groove (47 to 54, 184) which extends along the longitudinal groove (14, 19 to 23, 25, 26, 160).

11. A thread splicing device as claimed in Claim 3, characterised in that the compressed-air outlet is located in the groove (47 to 54, 1 84).

12. A thread splicing device as claimed in Claim 1 O or 11, characterised in that the lateral boundaries (55 to 62, 185, 186) of the groove (47, 48, 5Q, 52. 53, 184) are at an angle of approximately 30 degrees to one another.

13. A thread splicing device as claimed in one of Claims 1 to 12, characterised in that the two end sections (66 to 71) of the longitudinal groove (22, 23, 26) have a larger cross section than the central section (63, 64, 65).

14. A thread splicing device as claimed in Claim 13, characterised in that the enlarged cross section of the end sections (70, 71) extends towards the sides of the longitudinal groove (26).

1 5. A thread splicing device as claimed in Claim 13 or 14, characterised in that the enlarged cross section of the end sections (66 to 71) extends towards or from the groove bottom (44, 46).

1 6. A thread splicing device as claimed in one of Claims 1 to 15, characterised in that the ratio of the longitudinal groove length to the longitudinal groove cross section is in the range of 0.5 to 1.5.

17. A thread splicing device as claimed in one of Claims 1 to 15, characterised in that the ratio of the longitudinal groove length to the longitudinal groove cross section is in the range of 2.5 to 4.0.

18. A thread splicing device as claimed in one of Claims 1 to 17, characterised in that the compressed-air channel (27 to 39, 1 63 to 169) in the splicing head ends in an air-outlet nozzle (92, 92' to 108,142', 177 to 182) which has a smaller free cross-sectional area and/or a crosssectional shape which differs from that of the compressed-air channel.

19. A thread splicing device as claimed in Claim 18, characterised in that the compressed-air channel (27 to 39, 1 63, 164, 166 to 169) and/orS the air-outlet nozzle (92, 92', 93, 96 to 100, 105, 108, 142', 177, 179 to 182) is provided in the intersection of two planes of symmetry (142, 143) of the longitudinal groove (14', 1 57, 159 to 162).

20. A thread splicing device as claimed in Claim 1 8 or 19, characterised in that the longitudinal axis of the air-outlet nozzle (95) is directed towards one side wall of the longitudinal groove r18).

21. A thead splicing device as claimed in one of Claims 1 to 20, characterised in that the compressed-air channel (27, 35, 37, 38, 39, 168) is connected to several air-outlet nozzles (92', 92",99',99", 101 to 108,181', 181") which open into the splicing chamber.

22. A thead splicing device as claimed in Claim 21, characterised in that the air-outlet nozzles (101 to 104, 106,107) are provided at intervals to the left and right of the plane of symmetry (146) which passes through the length of the groove (24,25,26).

23. A thread splicing device as claimed in Claim 21 or 22, characterised in that the air-outlet nozzles (92', 92", 99', 99", 101 to 104, 106,107, 181', 181") are provided at intervals to the left and right of the plane of symmetry (147) which passes crosswise through the longitudinal groove.

24. A thread splicing device as claimed in one of Claims 21 to 23, characterised in that one of the air-outlet nozzles (105, 108) is provided in the intersection of the planes of symmetry.

25. A thread splicing device as claimed in one of Claims 1 to 24, characterised in that the central axes of the air-outlet nozzles (92', 92", 99', 99", 101 to108,181',181")areparalleltothelineof intersection of the planes of symmetry (146, 147) of the longitudinal groove (24).

26. A thread splicing device as claimed in one of Claims 21 to 25, characterised in that the compressed-air channel (27, 35, 37, 38, 39, 168) in the splicing head has a free cross-sectional area which is larger than that of the air-outlet nozzles (92',92",99',99", 101 to 108,181', 181").

27. A thread splicing device as claimed in one of Claims 21 to 26, characterised in that the airoutlet nozzles (99', 99") have a cross-sectional shape which differs from that of the compressedair channel (35).

28. A thread splicing device as claimed in one of Claims 1 to 27, characterised in that the compressed-air channel (28) is provided with a turbulence producer (141,202).

29. A thread splicing device as claimed in Claim 28, characterised in that the turbulence producer consists of an obstacle which extends across the compressed-air channel.

30. A thread splicing device as claimed in Claim 28, characterised in that the turbulence producer (141,202) consists of macroscopic wall unevennesses.

31. A thread splicing device as claimed in Claim 30, characterised in that the wall unevennesses consist of a screw thread (141,202) which is provided in the wall of the compressed-air channel (28, 37).

32. A thread splicing device as claimed in one of Claims 1 to 31, characterised in that the ratio of the cross section of the longitudinal groove to the total cross section of the air-outlet nozzles is in the range of 1.4 to 4.0.

33. A thread splicing device as claimed in one of Claims 1 to 31, characterised in that the ratio of the cross section of the longitudinal groove to the total cross section of the air-outlet nozzles is in the range of 7 to 9.

34. A thread splicing device as claimed in one of Claims 21 to 33, characterised in that at least one air-outlet nozzle (99', 99", 105, 108) ends in the groove (47,51,53,54) of the longitudinal groove (14,22,25,26).

35. A thread splicing device as claimed in one of Claims 21 to 34, characterised in that the airoutlet nozzles (99', 99", 106, 107, 108) are distributed over the central section (63, 65) and/or the end sections (66, 67; 70, 71) of the longitudinal groove (22, 26).

36. A thread splicing device as claimed in one of Claims 1 to 35, characterised in that thread guiding means and/or air guiding means (187, 188; 190 to 193) are provided at the ends of the longitudinal groove (161, 162).

37. A thread splicing device as claimed in Claim 36, characterised in that the thread guiding means and/or air guiding means consist of thread and air guiding plates (187, 188) which partly close the groove ends.

38. A thread splicing device as claimed in Clairn 36, characterised in that the thread guiding means consist of thread guides (1 90 to 1 93) which project from the longitudinal groove (162).

39. A thread splicing device as claimed in one of Claims 1 to 38, characterised in that the airoutlet nozzle (92', 177, 179 to 182) is formed by a slot which is located in the plane of symmetry which passes lengthwise through the longitudinal groove 157,159 to 162).

40. A thread splicing device as claimed in one of Claims 1 to 39, characterised in that the splicing head (1 to 13, 150 to 156) has an attachment bracket (72 to 84, 1 70 to 175) which projects into the basic body (86) and through which the compressed-air channel (37 to 39, 1 63 to 1 69) passes.

41. A thread splicing device as claimed in Claim 40, characterised in that the attachment bracket (72 to 84,163 to 169) has a cylindrical external suidace with a flat (91) and the basic body (86) has a holding element (90) which is directed toward the flat (91).

42. A thread splicing device as claimed in one of Claims 1 to 41 , characterised in that the cover (109), which temporarily covers the longitudinal groove (14 to 26, 14') during splicing, projects from the splicing head (1, 158) in the longitudinal direction of the longitudinal groove (14, 14') and comprises thread hold-downs (116, 117) at its ends.

43. A thread splicing device as claimed in Claim 42, characterised in that the thread holddowns (116, 117) comprise air guiding surfaces (11 8, 11 9) which are directed obliquely toward the travel direction (120) of the threads (114,115) to be spliced.

44. A thread splicing device substantially as described herein with reference to the accompanying drawings.