EP0489225B1 - Two-for-one twisting spindle with pneumatic threading device - Google Patents

Description

The invention relates to a double-wire twisting spindle with a compressed air-operated threading device with the features from the preamble of patent claims 1 or 6.

Such a double-wire twisting spindle is described in EP 00 26 159 B1. In this known device, the compressed air stream emerging from the thread guide channel, which carries the thread end, is guided against a deflection plate. This baffle is fixed to the turntable of the spindle or optionally adjustable on the spindle, at a point between the circular arc described by the outer opening of the thread guide channel and the outermost edge of the turntable. It is designed and aligned so that its upper end is at least at the level of the central axis of the outer opening of the thread guide channel, and the extension of its front surface is substantially tangent to the second guide surface which is curved convexly upwards.

It is in the above Document already pointed out that the so-called Coanda effect is presumably used in the device described, according to which an air jet guided along a convexly curved surface is deflected, in that it tends to follow the curvature of this surface.

In this known device, however, the deflection of the air jet is essentially caused by the baffle plate.

The known device has the disadvantage that the baffle plate must either be arranged around the entire turntable or a positionally accurate shutdown of the outer opening of the thread guide channel relative to the baffle plate or an adjustment possibility of the baffle plate is necessary to enable the threading process. This is complex and particularly unfavorable for automatic threading.

Another disadvantage of this known device lies in the contamination of it during the twisting process surface of the fixed deflector plates not touched by the thread. Because of the fluctuations in the position of the thread balloon, there is a risk that thread parts will touch the soiled surfaces, which leads to a reduction in the quality of the thread.

One possibility of thread deflection without a fixed deflection plate is described in DE 29 39 593 C2. A second compressed air jet is used here, which redirects the compressed air jet radially emerging from the thread guide channel, including the thread, upward at approximately a right angle. This solution is also relatively complex and requires that the outer opening of the thread guide channel be shut down in a positionally accurate manner with respect to the second compressed air jet.

The invention has for its object to provide a double wire twisting spindle with the above. To design features so that an automatic threading of the thread is possible without the arrangement of a baffle plate fixed relative to the rotatable parts of the spindle.

This object is achieved according to the invention with the features from the characterizing part of independent patent claims 1 or 6. Advantageous developments of the invention are described in the dependent claims.

The invention is based on the knowledge that the use of the Coanda effect on a double-wire twisting spindle for deflecting the thread emerging from the thread guide channel without arranging one fixed baffle is possible and can only be achieved by measures on the spindle rotor. A prerequisite for this is that the expansion of the compressed air jet in a direction perpendicular to the guide surface is kept as small as possible.

As described below with the aid of exemplary embodiments, both the influencing variables for the secure attachment of the air jet to the convexly curved second guide surface and also the features of the spindle rotor of a double-wire twisting spindle specified in terms of textile technology must be taken into account. The design of the double-wire twisting spindle according to the invention has the advantage that it is not necessary to stop the spindle rotor in a precise position and no deflecting plates that tend to become dirty are required.

Exemplary embodiments for a double-wire twisting spindle according to the invention are explained in more detail below with reference to the accompanying drawings.

• Figur 1 in teilweise geschnittener perspektivischer Seitenansicht eine Doppeldraht-Zwirnspindel mit automatischer Einfädelvorrichtung;
• Figur 2 in einem gegenüber Figur 1 detaillierter ausgeführten, teilweise perspektivischen Vertikalschnitt einen Teil des Drehtellers und der Fadenspeicherscheibe der Doppeldraht-Zwirnspindel im Bereich des äußeren Endes des Fadenleitkanals bei einer ersten Ausführungsform der Erfindung;
• Figuren 2a und 2b in einer stark schematisierten Darstellung die geometrischen Verhältnisse im Bereich der Anschlußstelle der zweiten Leitfläche an die erste Leitfläche im Bezug auf die Ausführungsform nach Figur 2;
• Figur 3 in einer schematischen, perspektivischen Darstellung Drehteller und Spulenträgerschutztopf der Doppeldraht-Zwirnspindel nach Figuren 1 und 2;
• Figuren 4 und 5 in Draufsicht den Keilspoiler im Fadenleitkanal bei einer zweiten und dritten Ausführungsform der Erfindung;
• Figur 6 in einer vergrößerten Seitenansicht in Einzeldarstellung den Keilspoiler nach Figur 4;
• Figur 7 in einer perspektivischen, teilweise geschnittenen Darstellung Teller und Fadenspeicherscheibe einer Doppeldraht-Zwirnspindel bei einer vierten Ausführungsform der Erfindung;
• Figur 8 in einem Vertikalschnitt einen Teil des Tellers und der Fadenspeicherscheibe einer Doppeldraht-Zwirnspindel im Bereich des äußeren Endes des Fadenleitkanals bei einer fünften Ausführungsform der Erfindung;
• Figur 9 in einer perspektivischen, teilweise geschnittenen Darstellung Drehteller und Fadenspeicherscheibe einer Doppeldraht-Zwirnspindel bei einer sechsten Ausführungsform der Erfindung

The drawings show:

• Figure 1 in a partially sectioned perspective side view of a double-wire twisting spindle with automatic threading device;
• FIG. 2 shows a part of the turntable and the thread storage disk of the double-wire twisting spindle in a partially perspective vertical section compared to FIG. 1 in the region of the outer end of the thread guide channel in a first embodiment of the invention;
• Figures 2a and 2b in a highly schematic Representation of the geometric relationships in the area of the connection point of the second guide surface to the first guide surface in relation to the embodiment according to FIG. 2;
• Figure 3 is a schematic, perspective view of the turntable and bobbin protection pot of the double-wire twisting spindle according to Figures 1 and 2;
• Figures 4 and 5 in plan view of the wedge spoiler in the thread guide channel in a second and third embodiment of the invention;
• FIG. 6 shows the wedge spoiler according to FIG. 4 in an enlarged side view in individual representation;
• FIG. 7 shows a perspective, partially sectioned representation of the plate and thread storage disk of a double-wire twisting spindle in a fourth embodiment of the invention;
• Figure 8 is a vertical section of part of the plate and the thread storage disk of a double-wire twisting spindle in the region of the outer end of the thread guide channel in a fifth embodiment of the invention;
• FIG. 9 shows a perspective, partially sectioned illustration of a turntable and thread storage disk of a double-wire twisting spindle in a sixth embodiment of the invention

In the following, the known structure of a double-wire twisting spindle with a compressed air-operated threading device is explained in more detail with reference to FIG. 1.
The double-wire twisting spindle consists of the whorl 1, the turntable 2 with thread storage disk 3 and the protective pot 5, in which a delivery spool Sp is inserted. The protective pot sits from the protective pot jacket 6, the protective pot base 4 and the protective pot hollow hub 7 together. The protective pot 5 is placed on the spindle rotor 24 with the interposition of bearings 22, 23.

The protective pot base 4 is provided with a radially extending channel 10. The outer mouth of the channel 10 is opposite an opening 13.1 in the balloon limiter 13. A connector 11, which is connected to a compressed air source (not shown), can be inserted through the opening 13.1 in order to pressurize the channel 10 with compressed air.

A chamber 9 adjoins the inner end of the channel 10, in which an injector nozzle 25 is arranged in the inlet opening of a thread guide channel 12 guided through the spindle rotor 24. A thread brake 8 is arranged in the protective pot hollow hub 7 above the injector nozzle 25 in the usual way.

If a thread F coming from the delivery spool Sp is to be threaded, the connecting piece 11 is connected to the channel 10, so that compressed air passes through the channel 10 and the chamber 9 to the injector nozzle 25. The suction flow generated in this way causes the thread F held at the upper end of the thread inlet tube 26 to be sucked in and, after passing through the thread brake 8 and the injector nozzle 25, to be conveyed by the compressed air jet through the thread guide channel 12 until it emerges from the outer opening 12.2 of the radial one in the thread storage disc 3 extending part 12.1 of the thread guide channel 12 emerges. As shown in Figure 1, Should the compressed air jet emerging from the outer opening 12.2 of the thread guide channel 12 be deflected upwards such that the thread F enters the space between the protective jacket 6 and the balloon limiter 13 and is guided upwards in this space so that it is at the upper edge of the Balloon limiter 13 can be detected by the operator or an automatic device.

The following describes with reference to FIG. 2 which influencing variables have to be taken into account in order to achieve a safe upward deflection after the compressed air jet has emerged from the thread guide channel 12, without a fixed deflection plate being arranged outside the turntable.

On its underside, the turntable 2 has, at least in the area of the outer opening 12.2 of the thread guide channel 12, a first guide surface 14 adjoining this opening 12.2, to which a second guide surface 15 curved convexly upwards is connected. The beam should be guided along these two guide surfaces and deflected upwards in such a way that the angle α between the vertical and the thread is as small as possible.

• der Krümmungsradius R der zweiten Leitfläche 15;
• die Ausdehnung h des Druckluftstrahls in vertikaler Richtung;
• der Winkel β1 zwischen der oberen Wand des äußeren Endes 12.1 des Fadenleitkanals und der Horizontalen;
• der Winkel β2 zwischen der ersten Leitfläche 14 und der Horizontalen.

It has been shown that the following variables that can be read from FIG. 2 are important for such a deflection using the Coanda effect:

• the radius of curvature R of the second guide surface 15;
• the extent h of the compressed air jet in the vertical direction;
• the angle β1 between the top Wall of the outer end 12.1 of the thread guide channel and the horizontal;
• the angle β2 between the first guide surface 14 and the horizontal.

When examining and selecting the conditions for a perfect deflection of the compressed air jet, it must be borne in mind that with the classic Coanda effect, surfaces are required that are even in the direction transverse to the jet and are only curved in the jet direction. This is not the case with a double-wire twisting spindle because the protective pot jacket 6 and the turntable 2 are curved transversely to the beam direction. Furthermore, the different operating conditions on a double-wire twisting spindle during the threading process on the one hand and normal operation on the other hand must be taken into account. During the threading process, the thread emerges from the outer opening 12.2 of the thread guide channel and is to be deflected upwards immediately. During normal operation, the thread emerges from the outer opening 12.2 of the thread guide channel and lies against the circumference of the thread storage disk 3 in possibly several wraps.

It has proven to be advantageous if R is chosen to be as large as possible and h as small as possible. For technological reasons, however, R cannot become arbitrarily large, because on the one hand the thread detaching from the turntable 2 should have a defined run-off point before entering the thread balloon and on the other hand the height of the thread balloon should be as small as possible.

The size h cannot be made arbitrarily small be, since a safe passage of the thread in the compressed air flow through the outer opening 12.2 of the thread guide channel and a trouble-free construction of the storage on the circumference of the thread storage disk 3 must be ensured in particular at a storage angle of more than 360 ^o .
For this it is necessary that the thread runs into the first loop at the lowest point of the thread storage disc groove and that the second turn of the storage is placed on the thread storage disc at a sufficient distance above the first thread system. A disturbance of these conditions can lead to a thread break.

It has been shown that good results are obtained if R / h ≥ 3 applies to the ratio of radius of curvature to beam expansion.
Particularly good results are obtained with a ratio R / h ≥ 4.

The angles β1 and β2 should be large in order to achieve a favorable direction of the compressed air jet. An increase in the angle is opposed by economic reasons that are related to the filling volume of the spindle. It would then either have to reduce the diameter of the protective pot 5 while maintaining the height or be designed higher while maintaining the diameter, which should be avoided.

It has been found that particularly favorable results are obtained if the following applies in any case: β1> β2, where β2 = 0.

The tangent T on the downstream side of the second Guide surface 15 should run as vertically as possible.

The curved second guide surface 15 can be connected to the first guide surface 14 in such a way that the first guide surface 14 coincides with the tangential plane to the second guide surface 15 at the connection point of the two guide surfaces. But this is by no means mandatory. It has been found that it can be advantageous if the first guide surface 14 encloses a predetermined angle with this tangential plane. The geometric conditions to be observed here are explained below with reference to FIGS. 2a and 2b. To describe the geometric conditions, in addition to the angle of rise β2 of the first guide surface 14 to the horizontal, the angle δ which the tangential plane TE forms with the second guide surface 15 at the connection point A of the first guide surface 14 to the second guide surface 15 with the horizontal. As can be seen from FIGS. 2a and 2b, the tangential plane TE may rise (FIG. 2a) or decrease with respect to the horizontal (FIG. 2b). In Figures 2a and 2b, the relationships are shown with the aid of a coordinate system, the origin of which lies in the connection point A of the first guide surface 14 to the second guide surface 15, the x-axis horizontally to the right in the drawings and the y-axis vertically in the drawings runs upwards. The coordinate system is indicated by dash-dotted lines. The center of curvature of the second guide surface 15 is designated KM. As can be seen from the figures, a tangential plane TE increasing with respect to the horizontal x means an angle δ which is positively counted in the coordinate system in the counterclockwise direction. The following applies: 0 <δ <+ 90 °. A falling tangent plane means an angle δ negatively counted clockwise in the coordinate system and the following should apply here -90 ° <δ ≤ 0.

For the rising angle δ of the first guide surface 14 to the horizontal, the relationship δ β β2 <+90 ^o applies in the case of the rising tangential plane TE (FIG. 2a). In the case of a falling tangent plane (FIG. 2b), the relationship 0 ≤ β2 <+90 ^o + δ applies.

In FIG. 2a, the smallest possible angle β2 for the angle δ drawn for the rising tangential plane TE is entered in dashed lines as β2 min. It runs in the direction of the tangential plane TE. A horizontal arrangement of the first guide surface 14 is therefore only possible if the tangential plane TE also runs horizontally.

In Figure 2b, the upper limit, which the angle β2 may no longer assume, is shown in dashed lines and designated β2 max. In this case, the first guide surface 14 would run perpendicular to the tangential plane TE. When the tangential plane TE falls, however, β2 can assume the value 0 without δ simultaneously having to assume the value 0.

If the relationships specified above are observed, the compressed air jet moving along the first guide surface 14 is guided along the second guide surface 15 under the effect of the Coanda effect.

In Figure 3, the course of the compressed air jet D along the second guide surface 15 and the protective jacket 6 is shown in perspective, wherein is indicated by the angle α by how much the compressed air jet D with the entrained thread deviates from the vertical direction. The angle should be made as small as possible.

A number of exemplary embodiments are described below with reference to FIGS. 4 to 8, in each of which the extent h of the compressed air jet is influenced in the vertical direction in different ways. In the basic illustration according to FIG. 2, the size h is given by the vertical width of the outer opening 12.2 of the thread guide channel. Since, as already explained above, this opening width cannot be made arbitrarily small, a wedge spoiler will be placed on the lower wall of the end section 12.1 of the thread guide channel in the region of the outer opening 12.2 in this exemplary embodiment in order to reduce the value h. This is shown in Figures 4 to 6.

According to FIG. 4, a wedge spoiler 16 is used which extends in the horizontal direction only over a central area of the outer opening 12.2. In the embodiment according to FIG. 5, the wedge spoiler 17, viewed in the flow direction, is arranged in front of the outer opening 12.2.

FIG. 6 shows a possible profile of the wedge spoiler 16 in a vertical plane. The wedge spoiler has a profile that initially rises linearly in the outflow direction and then curves upward in a concave manner. The shape of the wedge spoiler reduces the jet height and achieves a smaller effective value of h.

Another measure with which such a reduction in the value of h can be achieved is provided in the embodiment according to FIG. Here, seen in the direction of flow, a spoiler in the form of a ring segment 18 is arranged immediately after the outer opening 12.2 of the thread guide channel, which is directed upwards and can, for example, have a profile that curves concavely upwards. This can be seen clearly from the embodiment according to FIG. 8 with a ring segment spoiler 19. The ring segment spoilers 18 or 19 can extend over part of the circumference of the storage disc or as a full ring over the entire circumference of the storage disc 3.

A further measure is shown in FIG. 9 in order to achieve a particularly effective beam deflection. In this embodiment, a vertically upward baffle plate 20 is arranged in the outer opening 12.2 of the end section 12.1 of the thread guide channel at the lower exit edge and extends over a predetermined part of the width and the height of the outer opening 12.2. The sharp edge of this baffle causes a strong constriction of the compressed air jet directed upwards and thus a reduction in the effective value of size h which exceeds dimension "a". The free course of the thread in the thread storage disc groove over the circumference of the thread storage disc is ensured in this embodiment. For the safe functioning of this embodiment, the following should apply to dimension "a" in FIG. 9: 1 mm <a <2 mm.

Claims (12)

1. Two-for-one twisting spindle with pneumatic threading device, through which the thread is transported by means of a compressed air jet through the thread guide channel of the thread storage disc, wherein adjoining the outer opening of the thread guide channel, a first guide surface arranged on the underside of the revolving plate located above the thread storage disc is provided, said first guide surface merging into a second guide surface extending upwards in a convex curve, characterised in that the expansion h in the vertical direction of the compressed air jet (D) discharging from the outer opening (12.2) of the thread guide channel (12) and the dimensions of the radius of curvature R of the second guide surface (15) are such that the ratio of radius of curvature R to jet expansion h equals R/h ≥ 3, and that β1 > β2 applies for the relation between the angle of ascent β1 of the upper wall of the outer end (12.1) of the thread guide channel (12) to the horizontal and the angle of ascent β2 of the first guide surface (14) to the horizontal, and that the expansion h of the compressed air jet (D) in the vertical direction is determined by the action of a wedge-shaped spoiler (16, 17) sloping upwards and outwards arranged on the lower wall of the thread guide channel (12) in front of the outer end (12.2) thereof.
2. Two-for-one twisting spindle according to Claim 1, characterised in that, viewed in the direction of outward flow, the profile of the wedge-shaped spoiler (16) initially slopes linearly upwards and then extends upwards in a concave curve.
3. Two-for-one twisting spindle according to Claims 1 or 2, characterised in that the width of the wedge-shaped spoiler (16) is smaller than the width of the thread guide channel (12.1) by a predetermined amount.
4. Two-for-one twisting spindle according to one of Claims 1 to 3, characterised in that the outer end of the wedge-shaped spoiler (16) essentially coincides with the outer opening (12.2) of the thread guide channel (12).
5. Two-for-one twisting spindle according to one of Claims 1 to 3, characterised in that, viewed in the direction of outward flow, the outer end of the wedge-shaped spoiler (17) is arranged at a predetermined distance in front of the outer opening (12.2) of the thread guide channel (12.1).
6. Two-for-one twisting spindle with pneumatic threading device, through which the thread is transported by means of a compressed air jet through the thread guide channel of the thread storage disc, wherein adjoining the outer opening of the thread guide channel, a first guide surface arranged on the underside of the revolving plate located above the thread storage disc is provided, said first guide surface merging into a second guide surface extending upwards in a convex curve, characterised in that the expansion h in the vertical direction of the compressed air jet (D) discharging from the outer opening (12.2) of the thread guide channel (12) and the dimensions of the radius of curvature R of the second guide surface (15) are such that the ratio of radius of curvature R to jet expansion h equals R/h ≥ 3, and that β1 > β2 applies for the relation between the angle of ascent β1 of the upper wall of the outer end (12.1) of the thread guide channel (12) to the horizontal and the angle of ascent β2 of the first guide surface (14) to the horizontal, and that the expansion h of the compressed air jet (D) in the vertical direction is determined by the action of an impact plate (20), which is arranged essentially in the outer opening (12.2) of the thread guide channel (12.1) on the lower outlet edge, is directed vertically upwards and extends at least over a predetermined portion of the width of the thread guide channel and over a predetermined portion of its height, the upper contour terminating in a sharp edge.
7. Two-for-one twisting spindle according to Claim 6, characterised in that the ratio for the height a of the impact plate (20) is: 1 mm < a < 2 mm.
8. Two-for-one twisting spindle according to one of Claims 1 to 7, characterised in that the ratio of the radius of curvature R to the jet expansion h is: 3 ≤ R/h ≤ 5.
9. Two-for-one twisting spindle according to Claim 8, characterised in that the ratio of the radius of curvature R to the jet expansion h amounts at least approximately to the value R/h = 4.
10. Two-for-one twisting spindle according to one of Claims 1 to 9, characterised in that the second guide surface (15) has a vertical tangent (T) at its upward pointing end.
11. Two-for-one twisting spindle according to one of Claims 1 to 10, characterised in that δ ≤ β2 < +90° applies for the relation between the angle of ascent β2 of the first guide surface (14) to the horizontal and the angle δ between the tangential plane (TE) onto the second guide surface (15) at the connection point (A) of the first guide surface (14) to the second guide surface (15) and the horizontal in the case of the tangential plane (TE) ascending with respect to the horizontal and with n < δ < +90°.
12. Two-for-one twisting spindle according to one of Claims 1 to 9, characterised in that 0 < β2 < +90° applies for the relation between the angle of ascent β2 of the first guide surface (14) to the horizontal and the angle δ between the tangential plane (TE) onto the second guide surface (15) at the connection point (A) of the first guide surface (14) to the second guide surface (15) and the horizontal in the case of the tangential plane (TE) descending with respect to the horizontal and with -90° < δ ≤ n.

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