CS258980B1 - Device for yarn drawing-off from spinning rotor during break spinning - Google Patents

Abstract

The device is handled by a detention member twists, provided for this purpose once or several shaped functional surfaces, located separately from the drain funnel through which the spun yarn is withdrawn from the driven spinning rotor. Separated placing this member at a distance appropriate one to two average the length of the spun fibers from the input an effective containment is achieved in the funnel opening twists in the pulled-out Wood without this attribute would rub against the molded functional surface area, thereby avoiding increased clogging of the spinning groove the rotor.

Description

SUMMARY OF THE INVENTION The present invention relates to a device for withdrawing yarn spun in rotor spinning units of an open-end spinning machine, wherein the yarn formed by twisting the fiber ribbon is withdrawn from the rotating spinning rotor via a discharge funnel arranged centrally to the spinning rotor.

In this method of spinning, it is a problem how to suitably provide the conveying means for withdrawing the yarn from the rotor, since this substantially influences the transfer of the twists into the rotating open end of the yarn, the amount of axial forces in the yarn and the yarn abrasion intensity. The influence of these factors increases critically with increasing production parameters of the spinning machine.

It is known from the theory and practice of open-end spinning of yarn in spinning rotors that it is possible to increase the twist transfer by suppressing the possibility of the yarn rotating about its axis as close as possible to the functional surface of the drain funnel. The prior art arrangement of the yarn withdrawal paths seeks to solve this problem by various means.

For example, the yarn draw-off from the spinning rotor is designed so that within the rotor spinning unit body in close proximity to the funnel through which the yarn is drawn at a right angle of wrapping, a further bend is performed over the abrasion-resistant material bent exhaust pipe connected to the funnel.

While this solution somewhat improves the returning of the twists to the spinning rotor and thus increases the spinning stability, on the other hand, the axial forces in the yarn are increased, which has an adverse impact η »increased yarn breakage. Also, with this treatment, the spinning conditions deteriorate, since returning the yarn end is more difficult, and at the moment of spinning, the impact in the yarn being drawn off is too high.

It is also known to incorporate fixed or movable twist-retention members in the form of braking elements (SU 412 804, SU 438 316) immediately after the funnel to improve the twist transfer. However, this modification of the yarn draw-off disturbs the smoothness of the walls of the draw-off tube required for easy introduction of the yarn end during spinning. Also, with the braking elements, the abrasion of the drawn yarn is increased, from which fiber fragments and dust are released, together with small impurities causing excessive fouling of the coupling rotor.

Various shaped outlets of the take-off tube (DE 21 30 722, DE 18 06 054, GB 1 569 123) are also proposed for the removal of yarn from the spinning rotor. However, due to the direct connection of the take-off tube to the vacuum spinning space inside the rotor, dust and filament particles are released by abrasion of the yarn on the shaped orifice, which are sucked back into the rotor, causing premature fouling of the collecting groove. Also, this modification increases the axial force in the yarn being drawn, resulting in increased tear.

According to another solution, the axial force in the yarn due to the increasing centrifugal force acting on the drawn yarn from the high-speed spinning rotors is prevented by a coaxial arrangement of the take-off nozzle in the axis of the funnel, thereby eliminating further bending of the yarn. With this arrangement of the exhaust path, very high operating speeds have been achieved without having to reduce the inner diameter of the spinning rotor. Another advantage of this embodiment is

- 3 258 980 easy yarn spinning, which returns to the rotor directly. However, in order to achieve the required level of twist retention, which is necessary to maintain the spinning stability, it has proven necessary to increase the efficiency of the functional surfaces of the drain funnel by the twist retention member by means of grooves or grooves on these surfaces. However, the grooved funnel treated in this way is abraded when the yarn is drawn off, causing increased clogging of the collecting surface of the spinning rotor. Grooved funnels also need to be replaced more often due to their rapid wear.

Increased transfer of the twists into the spun yarn should also be achieved by a rotating twist returning member arranged downstream of the take-off tube, which inserts an additional false twist into the yarn, thereby enhancing the effect of the drain funnel (JP 13073/71). energy requirements and investment associated with rotary installation and drive; cruel member in a spinning unit.

Problems with abrasion of the yarn when it is withdrawn from the spinning rotor are also caused by the proposed funnel with several friction surfaces provided with grooves, which, while spinning, acts as a twisting retention member, but on the other hand strongly abrases the yarn when it is being towed.

The reduction of the axial tension during the yarn draw-off was to be achieved by means of a rotating pulley located downstream of the discharge funnel and possibly equipped with a drive aid (DE 25 30 586). Even this solution proved to be too expensive, despite the problems with maintenance and lubrication of the miniature roller bearing.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the existing drawbacks associated with yarn draw-off from rotor spinning units by means of a device which can ensure good spinning stability by effectively retaining twists over a wide range of yarn fineness. collecting grooves of the spinning rotor with dust and dirt. The device should also allow easy re-insertion of the yarn end during spinning.

According to the invention, the yarn draw-off device of the spinning rotor satisfies these conditions by means of a funnel having a twist retaining member, wherein the invention is characterized in that the twist retaining member is located downstream of the outlet duct at one half to two average spun fiber lengths.

By separating the twist retainer from the functional surface of the spout in the range of one to two to two median lengths of spun fibers, the yarn is prevented from rotating axially without having to knurle the funnel so that there is no risk of excessive yarn rubbing. Also, excessive fouling of the collecting groove by the dust and dirt released from the yarn by a separate twist retaining member that flies away from the withdrawn yarn at a sufficient distance from the mouth of the drain funnel. A separate twist retaining member can also take advantage of the axial yarn draw-off in the axis of the funnel allowing spinning of the yarns at very high spinning rotor speeds without having to increase the axial forces in the yarn draw-off too much;

In this respect, good results according to the invention are obtained when the severity of the twisting retention effect of the separately placed twisting retention member expressed by the coefficient of increasing the relative axial force in the yarn by passing the yarn over this member is in the range of 1.05 to 1.4.

The device according to the invention also makes it possible to achieve good spinning stability over a wide range of finenesses of the produced yarns by making the position of the twist-retaining member adjustable so as to adjust the appropriate intensity of the twist-retaining effect.

258 980 in the spun yarn and also in that the twist-retaining member is adjustable in the direction of the yarn withdrawal from the drain funnel ·

According to the invention, the desired effect on the retention of twists in the yarn is achieved by such a treatment, wherein the twist retention member is provided with one or more shaped functional surfaces.

A simple means for retaining the twists in the yarn separate from the drain funnel is such that the member for retaining the twists in the yarn is a friction, ball or other braking element.

According to the invention, it is advantageous if the intensity of action of the twist-retaining member is variable or adjustable by zero or stepwise, or if the twist-retaining member is adjustable continuously or stepwise to adjust the position and distance to the funnel.

For the actual operation of the rotor spinning machine, it is also advantageous to have an arrangement in which the bend-retaining members are centrally adjustable ·

By centrally adjusting the spacing of the twist retaining members relative to the functional surfaces of the drain funnels, during spinning, the effect of these members on the twisting of the yarn within a given range can be fine tuned, thereby achieving favorable conditions in terms of both spinning stability and yarn quality.

For example, varying the intensity of the twist retention member may be achieved by varying the wrapped yarn around the shaped functional surfaces or by adjusting the position of the friction or other braking elements. In combination with this measure or separately, according to the invention, the adjustability of the effect for retention of twists in the yarn can also be applied by varying the distance

258,980 of this member relative to the drain funnel. However, its adjustability serves only to be able to adapt the twist retention intensity to the desired yarn characteristics as a function of its fineness, without excessively increasing the axial force in the yarn being withdrawn, which could result in permanent deformation of the yarn.

From an economic point of view, it seems very advantageous to have an arrangement of the device according to the invention in which the twist-retaining member is a yarn break-contact sensor.

in this case, the yarn break sensor fulfills two functions where, when spinning, its touch arm, supported in the working position by the yarn being drawn off, retains its functional surface of the yarn in the spun yarn, and reacts to this by turning it into the non-working position.

In another arrangement, the twist-retaining member may be provided such that the shaped functional surfaces are periodically displaceable in their position transverse to the direction of the yarn being withdrawn. In this arrangement, in addition to the actual retention of the twists, the member also assumes the function of a yarn breaker between the take-off rollers in order to reduce their local wear.

Another advantageous solution in terms of easy access to the spinning rotor when the spinning unit is tilted is an arrangement in which the torsion-retaining member is pivotable.

Common to these solutions is that the tuft retaining member is not part of or connected to the drain funnel.

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The use of a twist retaining member both increases the level of the internal twist moment in the forming yarn prior to the start of the funnel funnel surface and compensates for the unevenness in imparting a false twist through the funnel. Therefore, both placement and induced retention intensity are important for the reliable function of this member.

The twisting retention member is assisted in increasing the internal torque by contacting the shaped functional faces of the member with a force applied to the helical structure of the yarn, which temporarily deforms thereon, creating a rolling resistance moment that limits the twist of the twist. direction of yarn draw-off. The unevenness in the transfer of the twists through the funnel is counterbalanced by the self-regulating effect of the member which, when a greater number of twists occurs, temporarily increases the internal torque in the forming yarn, which in turn acts to move them to the rotating open end and vice versa. In order for this twist-retention member to fully exert its regulatory effect, both the distance of the member from the start of the functional surface of the drain funnel and the retention effect of the twist member must be consistent.

If the member is too short from the drain funnel, it would be necessary to select too high a retention effect in order to prevent excessive twisting of the member and thereby loss of its control capability. However, if the twist retaining member is too far from the drain funnel, the variation in the amount of internal torque in the forming yarn would be too small due to the unevenness in the twisting of the twist through the drain funnel, so that the compensating effect could not occur again.

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In order to achieve the required level of increased internal torque in the forming yarn, the twist retaining member must take into account the properties of the fibers being processed, the fineness of the spun yarn and the twist coefficient used. According to the invention, the spinning yarn with good spinning stability can be ensured by the proper control effect achievable when the distance of the member from the inlet opening of the drain funnel is between half and two average lengths of spun fibers. which limits the slippage of twists in the forming yarn.

The device according to the invention substantially reduces twist slip _? thus creating the yarn production conditions with good stability even at extremely high spinning rotor speeds.

An exemplary embodiment of the device according to the invention is shown schematically in the accompanying drawings, in which in a vertical axial section, FIG. 1 represents a spinning rotor with a twist retention member, FIG. 2 a twist retention member in two-wheel brake design; FIG. 4 shows a twist-retaining member having a longitudinally and transversely displaceable functional surface; and FIG. 5 a twist-retaining member having mutually displaceable shaped functional surfaces.

The spinning rotor 1 rotatably mounted in the spinning unit of the open-end spinning machine is connected to a device 2 for conveying the fibers deposited in the collecting groove 11. In the fiber conveying device a drain funnel J is provided with a functional surface 32 provided in the inlet 31 a twist retaining member 6 is provided downstream of the outlet channel 33 of the drain funnel having one or two shaped functional surfaces 46, 42.

AND

258 980

In the exemplary embodiment of FIG. 1, the shaped functional surfaces 41, 42 are adjustable against each other in the direction of the double arrows. In the embodiment of FIG. 2, the shaped functional surfaces 41, 42 of the member 6 are formed by pins that act as a two-pin brake, the rotation of which in the direction of the arrow can change the intensity of the twist retention. In the exemplary embodiment of FIG. 3, the twist-retaining member 6 is hinged away from the discharge funnel with its outer orifice in cooperation with the working position. In the embodiment of FIG. 4 is a member for retaining the twists displaceable in the longitudinal direction as indicated by the double arrow to set the desired distance L. At the same time £ member is designed so that it can change the angle of _wrap} and thus retention effect. In the case of a yarn break, when it is folded into the non-working position, it takes on the function of a yarn break sensor that turns off the fiber feed to the spinning unit.

In the exemplary embodiment of FIG. 5, the shaped functional surfaces 41, 42 of the member 6 are movable relative to each other in the direction of the arrows, thereby varying the intensity of the retention effect on the twists in the forming yarn.

During spinning, the individual fibers fed in the spinning unit of the open-end spinning machine by the fiber conveying device 2 are deposited in the collecting groove 11 of the driven spinning rotor 1 where they are twisted to the rotating open end 51 of the forming yarn. via a drain funnel J and through radiused or otherwise shaped surfaces 41, 42 of the member 4 located separately from the drain funnel at a distance L from its inlet opening 31.

The distance L is selected depending on the type and length of the spun fibers, the fineness of the spun yarn and the twist

- 10 258 980 coefficient. By rotating the open end $ 1 in the spinning rotor, an internal torque is generated in the forming yarn, by which the fibers are forced to assume a helical shape while at the same time moving the higher-torque twists to the lower-torque locations. This mechanism, together with the known effect of the functional surface 32 of the discharge funnel J on imparting a false twist, makes it possible to consolidate the fiber ribbon at the yarn forming point 12. In order to adequately transfer the twists to this point, the increased torque level is achieved by the twist retaining member 6 whose functional surfaces 41, 42 create the necessary force action on the helical structure of the yarn 2 ^and temporarily deform this, creating a rolling resistance moment limiting the twist slip into the filament. .

The increased torque in the yarn also acts backwardly to shift the twists into the rotating open end 51, thereby creating a self-regulating effect which eliminates the unevenness in the number of twists in the rotating branch of the open yarn end.

In the exemplary embodiment of FIG. 1, the distance L from the inlet bore 31 to the shaped surface 42 is fixed and only the intensity of the retention effect varies by shifting the shaped functional surfaces 41, 42 in the direction of the double arrows.

In another embodiment of FIG. 2, by rotating the two-pin brake of member 6, the retention effect intensity changes simultaneously with the distance L of the shaped functional surface 42 from the inlet opening 31 of the drain funnel.

- 11 258 980

In the simplified embodiment of FIG. 3, the twist-retaining member 6 is pivotable from the working to the non-working position and the retention effect is achieved by the interaction of its shaped functional surface 41 with the outlet channel 33 of the discharge funnel.

In the embodiment of FIG. 4, the member £ retention twists characterized by an adjustable distance L relative to the inlet opening 31 of the discharge funnel 2> while in the embodiment of FIG. ^5, each movable functional surfaces £ l £ 2 in the direction of arrows modified as necessary as strength retention and the distance L from the inlet opening J1 of the drain funnel 2.

In addition to improved spinning stability and reduced clogging of the spinning rotor collection groove with minimal increase in yarn axial force, the use of the twist retainer allows spinning of the yarn with reduced twist and increased draw speed while avoiding chafing of the yarn by a funnel. or other roughening element.

Claims (1)

Apparatus for withdrawing yarn withdrawn from a driven spinning rotor via a stationary discharge funnel with an inlet opening and a withdrawal channel coaxial with the rotor axis, wherein a yarn retaining member is provided downstream of the funnel, characterized in that the retaining member (4) The twist is located behind the outlet (33) of the exhaust duct. at a distance (L) from the inlet opening (31) of the drain funnel (3) equal to one half to two average spun fiber lengths.