The present invention concerns a ring for ring spinning and ring twisting machines, with a traveller flange and an annular traveller support surface arranged below the traveller flange on the ring inside, extending toward the inside, and connected with the traveller flange by a ring web.

A ring for such type, a so-called "non-unthreading ring", is known, which compared to the ordinary ring not provided with a traveller support surface, shows the advantage that upon stopping the working position - independently of whether the whole machine or just the working position concerned is stopped, e.g. for piecing a broken end - the traveller can rest with its inside leg on the traveller support surface and thus blocks the unthreading path of the thread or yarn. The thread or yarn thus remains trapped between the ring and the traveller and cannot unthread from the traveller.

The danger of unthreading is influenced by certain conditions, such as e.g. the type of material to be spun and the twist imparted to the yarn. The danger of unthreading increases with increasing twist, as a highly twisted yarn or thread tends to contract and to form loops over the path from the drafting arrangement onto the traveller and to the bobbin package while the spindle is at a standstill. The yarn is often pulled out of the traveller, i.e. is unthreaded under these circumstances.

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From Japanese Utility Application No. 32.263/1974 a ring of the type mentioned is known, in which the desired effect of "non-unthreading" is to be achieved by a combination of characteristics, which concern the ring as well as the tra¬ veller which rotates on the ring. The traveller shape is chosen more closed than normally used. The two open travelle legs arebent in hook form more towards the bridge of the traveller. Furthermore, the traveller flange of the ring contains on its lower part (at both sides of the ring web) a groove into which the hooked traveller legs can penetrate deeper under the flange than with ordinary rings. Finally a traveller support surface is provided below the traveller flange on the ring inside, which support surface is connec- ted with the traveller flange via a cylindrical ring web, against which support surface the inner leg of the traveller rests while the traveller is at a standstill. The traveller support surface in this arrangement is provided as an annula surface, an angle of about 120 being enclosed between the traveller support surface and the inner wall of the cylindri ring web adjacent to it.

This known ring shows the disadvantage that the use of a Special traveller is required which is of more closed'form than ordinary travellers, and which further is to be coordi- nated with a Special traveller flange with fitting grooves. On such a ring, placing and exchanging travellers are quite complicated operations. The known ring notwithstanding does not present sufficient safeguard against the danger of un- threading.

It thus is the object of the present invention to eliminate the disadvantages of the known ring and to propose a ring fo ring spinning and ring twisting machines, using which the danger of unthreading is prevented reliably and simply, norm traveller flange forms and traveller forms being applied.

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This objective is achieved by a ring for ring spinning and ring twisting machines with a traveller flange and with an annular traveller support surface arranged below the travel- 1er flange on the inside of the ring, connected with the traveller flange via a ring web, and extending toward the in¬ side, characterised in that between the traveller support surface and the adjacent inside wall of the ring web, which extends substantially vertically, an angle of less than 105° is enclosed, and that the inside diameter of the traveller support surface ranges between 95% and 105% of the inside diameter of the traveller flange.

According to a preferred embodiment of the invention the ring consists, in a manner known as such from the Japanese Utility Application cited, of two rigidly asse bled rings, the outer ring of which forms the traveller support surface. The two rings are assembled preferentially by applying an adhesive.

According to a further preferred design example ^' of the in¬ vention the ring forming the traveller support surface con¬ sists of plastic material.

Furthermore, the traveller support surface can be contained in a plane extending parallel to the traveller flange.

According to a further preferred embodiment of the invention the traveller support surface is provided with an inside edge, the radius of which ranges from 0,1 to 0,3 mm.

The invention is described in more detail in the following with reference to illustrated design examples. It is shown in:

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OMPI

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Fig. 1 the inventive ring shown schematically, during 95 Operation of the spinning position, in a section plane containing the ring axisj

Figs. 2 a detail each of the ring according to Fig. 1, and 3 namely in Fig. 2 during Operation of the spinning 100 position and in Fig.3 while the spinning position is at a standstill;

Fig. 4 the ring of the arrangement according to Figures 1 through 3, the traveller not being shown, also 105 in a section plane containing the ring axis;

Fig. 5 an alternative design exa ple of the inventive ring.

110 On a rotatably supported spindle 1 of a ring spinning or rin twisting position not shown in more detail, a yarn or thread bobbin 2 is placed. The spindle 1 is rotated by means not sh In a ring rail 3 a ring 5 is non-rotatably mounted in a cor- responding bore 4 concentrically with the spindle 1, on the

115 traveller flange 6 (comp, also Fig. 2) of which ring 5 the traveller 7 is dragged by the yarn 8 passing onto the bobbin 2. By this rotation of the traveller 7 the yarn 8 between th thread guide 9 and the traveller 7 is caused to form a ballo 10.

120

The inventive ring 5 is provided below the traveller flange with a part 12 which facing a substantially vertical ring we 11 (Fig. 2) protrudes toward the ring centre, the shoulder o which part 12 facing the traveller flange 6 forms a travelle

125 support surface 13. The traveller support surface 13 thus is arranged adjacent to the substantially vertical inside wall 14 of the ring web 11, and with said ring web 11 encloses an angle oi (comp. Fig. 4) which is of particular importance. A

substantially vertical wall is understood in this context to 130 designate a cylindrical wall or also a wall extending slightly conically.

In Operation (Fig. 2) the traveller 7 is held balanced under the influence of the centrifugal force and the yarn tension

135 acting upon it in such manner that it contacts the traveller flange at one point only, or along an arked leg surface of its inner leg 15 respectively. Between the end 16 of the inner traveller leg 15 and the traveller support surface 13 thUs in this State no contact is established, but a ple

140 clearance of the order of milli eters is maintained, which is ensured by suitably choosing the distance between the flange 6 and the traveller support surface 13.

During a standstill (Fig. 3) no centrifugal force acts onto 145 the traveller 7 and also the yarn tension has decreased to zero as no rotation prevails and as thus no air friction acts on -the yarn balloon 10. In this case now the end 16, or the end portion of the inner leg 15 respectively, rests on the traveller support surface 13, which is arranged at a distance 150 suitably chosen for this purpose, i.e. the traveller 7 tilts and rests with its end 16 on the surface 13. The traveller 7 in this State also rests with its outer leg 17 on a point 18 of the traveller flange 6. Also if a residual tension still prevails in the yarn 8 (which is quite likely in highly twisted 155 yarns and which results in unfavourable curl loop formation) the position of the traveller does not differ substantially from the position described above, as the forces still acting according to experience are minimal.

160 Experience has proven that the contact of the end 16 on the traveller support surface 13 effectively seals the passage- room of the yarn 8 between the traveller 7 and the traveller

flange 6. Thus the danger of unthreading, i.e. the danger tha the yarn 8 slips out of the traveller 7 during a standstill o 165 during a subsequent start-up phase, is decisively reduced, provided that the geometry of the traveller support surface 1 fulfils well determined requirements.

With reference to Fig. 4 these requirements are defined in 170 more detail, the ring alone (i.e. without the traveller) bein shown for simplicity. The ring 5 is to fulfil the following two requirements, namely:

a) the angle enclosed between the traveller support sur- 175 face 13 and the inner wall 14, adjacent to it, of the substantially vertical ring web 11 is to be smaller than 105 . Larger angles et do not sufficiently preclude the danger of unthreading;

180 b) the inside diameter d of the traveller support surface 1 is to be chosen in the ränge of 95% to 105% of the insid diameter D of the traveller flange 6.

Inside diameters d, which are chosen too large, i.e. in exces 185 of 105 of D, also do not sufficiently preclude the danger of unthreading. On the other hand, an inside diameter d chosen smaller than D can yield the considerable advantage that the traveller 7 is protected against being carried on by an over- filled bobbin package and thus is protected against being 190 pressed against the ring flange. Thus the danger of travelle jamming between the bobbin package surface and the traveller flange, which often results in damages to the traveller flan 6 and thus to the ring 5, can be entirely eliminated. Furthe more, using this arrangement the further advantage can be 195 achieved that the hairiness of the bobbin package surface is reduced owing to the grazing of protruding fibres. If, how-

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ever, the inside diameter d is chosen too s all, the bobbin package diameter m (Fig. 1) is reduced correspondingly, which for productivity reasons is undesirable. The above entioned 200 requirement for the inside diameter d takes care of all these factors and has proven to be an Optimum.

Furthermore, for the small radius r of the inside edge 21. of the traveller support surface 13 the preferred requirement

205 can be established, na ely that the radius r is to be chosen in the ränge from 0,1 and 0,3 mm. This ränge for the radius r has proven to be an Optimum for ensuring that the traveller support surface 13 yields its füll usefulness and for pre- venting any danger of damaging the bobbin package 2 by cutting

210 yarn layers due to an excessi.vely sharp edge 21.

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In the design example according to Fig. 5 the ring consists, in a manner known as such, of two rigidly joined rings 22 and 23, the outer ring 22. of which forms the traveller flange 24

215 and the inner ring 23 forms the traveller support surface 25. The ring 23 furthermore can be ade advantageously of a suit- able plastic material, and the two rings 22 and 23 can be joined adhesively along their co mon line of contact 26. The use of an adhesive as a ethod of joining the rings is parti-

220 cularly suitable as it is simple and avoids tensions in the rings, and as it ensures easy exchangeability of the inner ring 23 forming the traveller support surface 25. Furthermore, in Fig. 5 a particularly advantageous embodiment is shown, in which the traveller support surface is arranged in a plane

225 extending parallel to the traveller flange, i.e. in which the angle ϋ( is 90°.

The advantages of the present invention are seen in its simpli- city, which permits the use of traveller shapes and traveller 230 flange shapes which are available on the market, and in the high reliability concerning the elimination of the danger of

unthreading. Furthermore, if the inside diameter d is chosen smaller than D, a desirable protection against damages to th traveller flange and a reduction of hairiness of the bobbin package surface can be achieved. Furthermore, the proposed ring, which does not contain any grooves on the underside of the traveller flange, to a large extent is unsusceptible with respect to waste and dust accumulations.