GB2187211A - Thread spinning-in apparatus in an open-end spinning machine - Google Patents

Abstract

The apparatus is designed for returning thread to be spun in, by transferring means to the take-off tube (17) of a spinning unit and for reintroducing it through said tube (17) into the spinning rotor. According to invention, the thread transferring means consists of a guiding duct (16) and a continuing spinning-in duct (16.1) having an air-tight socket (18) to be put on the take-off tube (17) so that, in the spinning-in position, the ducts (16,16.1) form an extension of said tube (17). Thus the end cannot fail to be fed back through the take-off tube 17. Tube 16 has an end 19 for catching the end on bobbin 11. Tube 16, roller 46 for lifting bobbin 11 off its normal drive 9, lever 13 for separating rollers 7,8 and unit 21 for preparing the end to be fed back are all carried on a travelling service unit 1. <IMAGE>

Description

SPECIFICATION Thread spinning-in apparatus in an open-end spinning machine The invention relates to a thread spinning-in apparatus in an open-end spinning machine having a pluralityofspinning units, comprising a control device for lifting and driving a bobbin as well as for spacing thread take-off rollers apart fro each other, and a thread guiding duct having an inlet mouth, a longitudinal slot and means fortransferring thread to a thread take-off tube of the spinning unit.

An apparatus ofthis kind has been disclosed in the West German Published Application (DE-OS) No.

2,326,492. The control device and the kinematic relationship between its individual controlling el ements and the thread guiding or spinning-induct are therein arranged so that the thread end, after a thread breakage, be sucked offthethread package on the bobbin by an extended mouth of said duct and led therethrough into a suction duct. After a portion of unsuitable thread end has been optionally removed, a new end is taken over bytransferring means at the lower end ofthe spinning-in duct. Such thread transferring means is then swung toward the take-offtube of the spinning unit whereby the thread is delivered to said tube and sucked thereinto.During this thread transfer, or the swing of the spinninginduct, thread gets out ofthe duct through the longitudinal slit before its backward orspinning-in motion has been initiated.

A problem encountered in this operation lies in the transfer of thread by the respective means to the take off tu be, and in the deliverythereofthrough said tube into the spinning rotor. The thread transferring means are variously embodied, such as a gripper consisting of a roller and a pressure element, ortwo rolls on a lever (of West German Published Application (DE-OS) No.3,123,282). Acharacteristicfeature of such thread transferring means is in that a thread end portion protrudesthereoutand has to bedelive- red up tithe proximity ofthetake-offtube mouth.

Due to a vacuum produced inthetake-offtube,the thread end is either sucked in, or, additionally, stuck partially in by said transferring means. Because of its insufficient rigidity and an uncontrollable tendency to bending, the thread itself becomes a cause of failure when being introduced into the take-offtube and further on into the spinning rotor. Even if the thread is partially inserted in the take-offtube atthe beginning of spinning process, the inserted length amounts in the initial phase to no more than several mil I imetres. The thread is sucked into the take-off tube, due to a vacuum which is produced in the spinning rotor and which cannot be optionally increased.An axial force in the thread which arises by sucking it in while being introduced into the take-off tube, is generated by friction at air stream flowing around. The respective transferring means by which the thread is delivered to the mouth oftake-offtube, makes it free after the delivery and a partial insertion thereof into said tube, and returns then to its initial position whereupon any other thread control, save the above-mentioned axial force, gets lost. Since the inserted thread length, in this phase, is several mil iimetres only, also thisforce isvery small. Owing to thread hairiness, the thread is frequently entrapped by its hair at the edge ofthe take-offtube.Another problem to be coped with is in the thread adhesion such as, for instance, due static charge which manifests itself somewhere in the mechanism of service unit. Consequently, theth read stops in the take-off tube, and although it is returned by said service unit, it may get blocked somewhere on its passage so that itfailsto be spun in. Acritical drop of reliability of known apparatuses ofthis kind is especially observed when processing syntheticfibreswhich are particularly prone to get static charge. A charged thread has such an adhesion to individual elements that a relatively low vacuum in the take-offtube, even when a short inserted thread length, does not suffice to generate an appropriate axial force to overcome the thread blocking, be it caused by hairiness, or static charge.

It is an object of the present invention to eliminate the drawbacks of prior art as hereinabove referred to, and provide an improved apparatus which is able reliable to guide the thread into the take-offtube of the spinning unit and to deliver it into the spinning rotor.

The apparatus is simple, fail-safe and does not lay inadequate claims on manufacture.

According to the invention there is provided a thread spinning-in apparatus for use in an open-end spinning machine having a plurality of spinning units, comprising a control device for lifting and driving a bobbin as well as for spacing thread take-off rollers apartfrom each other, and a thread guiding duct having an inlet mouth, a longitudinal slit and means fortransferring thread to a thread take-off tube of the spinning unit, wherein at least the lower partofthethreadguiding ductisformedasathread spinning-in duct having thread transferring means in the form of an air-tight socket adapted to be put on thetake-offtube of a spinning unit, said spinning-in duct forming in its operative position an extension of said take-offtube with which it is connected during the spinning-in process through said air-tight socket.

Preferably, the inner diameter of at least lower part of the spinning-in duct corresponds to the inner diameter of the thread take-off tube ofthe spinning unit, and the spinning-in duct is formed by two coaxial tubes disposed one in the other and having each a longitudinal slit, at least one tube being rotatable and provided with a control arm coupled with a control device.

Another preferred embodiment consists in that the spinning-induct is composed of two half-partsfacing each other and forming a longitudinal slittherebetween, one part being journalled about a pivot fixed in a carrier, and provided with the control arm coupled with the control device.

The thread spinning-in duct is preferably provided with a nozzle connected to a source of pressure air.

An advantage of the apparatus ofthe invention consists in thatthe thread take-off tube of the spinning unit is suitably prolonged so that a longerthread section is exposed to the suction effect of spinning rotor. In the spinning-in process, the thread end is reliably delivered into the spinning rotor while any transfer and introduction thereof by means of transferring devices as disclosed in the prior art, is omitted. This contributes to a considerable simplicity of spinning-in means and increases the reliability thereof. Apartfrom this, the vacuum effect of spinning rotor can be promoted byan injection effect of pressure air.Another advantage is in thatthethread is held in the spinning-in duct during the entire spinning-in cycle and that the duct is notspaced apart fro said tube until the cycle has been ended.

In this way the perfect control of thread during the spinning-in process is attained. In case of a thread breakage during this process, such as due the absence of fibres in the spinning rotor, the thread remains in the spinning-in duct and need not be searchedforagain wherebythe process isaccelerated.

Some preferred embodiments of the invention will now be described by way of example with reference to the accompanying schematic drawings, in which Figure 1 is a perspective view showing the thread spinning-in apparatus with the spinning-in duct in its inoperative position when travelling along the spinning units of the open-end rotor spinning machine; Figure2 is a perspective view showing the same apparatus when beginning the service operation on the spinning unit where a thread breakage has occurred; Figure 3 is a perspective view showing the apparatus in the operative or spinning-in position; Figure 4 is a perspective view showing an a Iternative embodiment of the apparatus with a shortened spinning-in orthread guiding duct in the preparatory position;; Figure5isa detailed perspective view showing a variantofthespinning-in duct; and Figure 6is a sectional view showing a mode of coupling the air-tight socket of the spinning-in duct to the take-offtube ofthe spinning unit.

As can be seen in the drawings, and particularly Figure2thereof,the open-end rotorspinning machine includes a plurality of spinning units 4, a take-off roller7 with a pressure roller 8forming together a pair of take-off rollers, and a bobbin holder 10 carrying a bobbin 11 which is supported, in its operative position, by a driving ortake-up drum 9 and which, in its inoperative position orspinning-in position, is lifted and controlled by a travelling ser vice unit 1.

For performing the spinning-in process, the service unit 1 which is provided with rolls 2, 6fortravelling along the machine on rails 3, 5, is equipped with a control device 12 for controlling motions of the bobbin 11 during this process, a lifting device 13 for disconnecting thetake-off rollers 7, 8 from each other, means 14for guiding thread into the spinning unit4and preparing itfor being spun in, and afeeding device 1 5for controlling the fibre supply during the spinning-in process.

In aspects ofthe present invention, the arrangement of the apparatus in its complex is irrelevant. Its essential feature, however, is the fact that it comprises a thread guiding duct 16 which is displaceable from its inoperative position to the operative one and which, at least in its lower part, isformed as a spinning-in duct 16.1 having yarn transferring means in the form of an air-tight socket 18 which, in said operative position, is put on a thread take-off tube 17 of the spinning unit4. As shown in Figure 1,theopposite end of the guiding duct 16 is formed as an inlet mouth 19 which can be extended to correspond to the width of the bobbin 11. The thread guide duct 16 and the spinning-in duct 16.1 are provided with a longitudinal slit 20 extending throughout its entire length.The spinning-in duct 16.1 which isfixed in a carrier 21 can be provided at this place with a suction duct 22 connected through a flexible tube 22.1 two a vacuum source (not shown). In the mouth ofthesuc- tion duct 22 there is preferably arranged a rubbing disc 23 designed for severing the thread and for preparing its end for being spun in.

As can be seen in Figure 6, the inner diameter 16.2 of at ieast lower part of the spinning-in duct 16.1 is practicallythe same asthe inner diameter 17.1 of take-offtube 17 in order to obtain a uniform subatmospheric pressure airflow therein. The carrier 21 is journal led about a pivot 24 of a lever 25. The lever 25 is mountedforrotationtogetherwith a shaft 26 which can also reciprocate in axial direction so that the carrier 21 is given two motions of which each is separately controlled by not shown means such as pistons of pneumatic cylinders.

Figure 4 shows an alternative embodimentwhere each of the spinning units 4 is equipped with its own bobbin stopping and lifting device 27 that any lifting device, such as 13, on the service unit is unnecessary. The pressure roller 8 is here rotatable about a pivot on a carrying arm 28 which is journalled about a pivot 29 in the spinning unit frame. The carrying arm 28 carries a bobbin braking and lifting shoe 30.

Another lever 31 is also journalled about the pivot 29 and thrusted upward by a spring 32. The opposite end of the lever 31 is provided with a safety pin 33 which, in the spinning position, is engaged by a pawl 34journalled about an axle 35. The pawl 34 is coupled to a yoke of an electromagnet37.

In this embodiment, the spinning duct 16 iscomposed of two half-parts 38.1 and 39.1 facing each other and adapted so that the part 38.1 is made tiltable from the part 39.1 about a pivot 50 in the carrier 21. The other part 39.1 is connected with the carrier 21. The part 38.1 is coupled to a control device 43 by means of a lever 40 and a joint 42. The longitudinal slit 20 between said parts 38.1,39.1 arises by spacing them apart from each otherwhereas inthecoupled position the slit 20 is closed to avoid vacuum leakage in the duct.

Another variant of the spinning-in duct 16, 16.1 is shown in Figure 5. It consists of two coaxial tubes 38, 39 disposed one in the other and provided each with the longitudinal slit 20. The innertube 38 is rotatable to an extent and its motion is controlled bythe control arm 40 which is attached to said tube 38 and passes through an opening 41 in the outer tube 39.

The control arm 40 is coupled through a ball-and socketjoint 42 to the control device 43 such as piston of pneumatic cylinder. In one dead position of rotation ofthetube 38, the longitudinal slits 20 are blinded while in the opposite one the slits 20 face each other and form a free passage into the duct interior.

Adjacent the air-tight socket 18, the lower part ofthe spinning-in duct 16.1 can preferably be supplied with compressed air by a nozzle 44 communicating via pressure hose 45 with a source ofsuperatmospheric pressure air (not shown). In case of a sufficiently efficient pressure air source the suction duct 22 (Figures 1,2 and 3) may be omitted altogether since the introduction ofthread into the inlet mouth 19 ofthe guiding duct 16 is fully cared for by the injection effect of the nozzle 44.

The apparatus operates as follows: Afterathread breakage in a spinning unit4has been ascertained, the travelling service unit 1 is recalled to said unit and stopped here. This position is shown in Figure 1.

Figure 2 shows an intermediate position wherein the lifting device 13 disconnects the take-off rollers 7, 8 from each other. By axial motion of the shaft 26 the thread guiding duct 16,togetherwiththespinning-in duct 16.1, enters the spacing between the disconnected take-off rollers 7,8 and approaches by its extended mouth 19 the bobbin 11, due to a combined rotary motion of the shaft 26 and consequently ofthe lever 25 as well as to the motion of the carrier 21 about the pivot 24.By the control device 12, and particularly byathrust ofthe driving roll 46, the bobbin 11 is spaced apartfrom its driving ortake-up drum 9 whereupon its rotation is reversed by said roll 46 in the direction of full arrow. Thusthethread end is sucked into the inlet mouth 19 ofthe guiding duct 16 and further on into the suction duct 22. On its way, the thread gets into contact with the rubbing disc23 by which it is severed, and its new end is duly treated for being spun in.By motions of the shaft 26 and the carrier 21 aboutthe pivot24thethread guiding and spinning-inducts 16 and 16.1 are put bythe air-tight socket 18 on the take-off tube 17 (Figure 3). Then the suction in the duct 22 is stopped by known means, and the thread, by rotation of the driving roll 46 begins to take its reverse rotation. Sincethespinning-in duct 16.1 is coupled by its socket 18tothetake-off tube 17, thread is sucked into the rotor of the spinn- ing unit 4, and just after its end has been pierced to the fibrous ribbon in the rotor, the roll 46 beginsto rotate in the direction of outlined arrow whereby the normal thread withdrawal from the rotor is restored whilethebobbin 11 drops ontothetake-updrum 9.

The introduction ofthread into the spinning rotor by a vacuum produced therein can be promoted by injecting compressed airthrough the nozzle 44 whereby the thread is effectively blown into the rotor. To raise the suction effect in the extended mouth 19 of the guiding duct 16 and in the spinningin duct 16.1,the longitudinal slit 20 can be blinded during the spinning-in process (Figure 5).

In the next phase afterthe spinning-in, the spinning-in duct 16.1 together with its socket 18 is spaced, by rotary motions of said shaft 26 and carrier 21 aboutthe pivot 24, apartfromthetake-offtube 17 and displaced by the axial motion ofthe shaft 26 out ofthe space between the disconnected take-off rollers 7, 8whilethethread gets out of the duct 16.1 through the longitudinal slit 20.If the slit 20 has been blinded during the spinning-in process to raise the suction effect, it is opened again before the displacement of said duct 16.1 from the spinning-in position by supplying the control device 32 (pneumatic cylin- der) with compressed airwherebythe control arm 40 of the tube 38 is engaged by the cylinder piston. In this way the tube 38 isturned and the slits 20 get in register (Figure 5).

By swinging the lifting device 13 and tilting the control device 12 out of the spinning-in position, the spinning-in process is ended. Thread is nipped between the take-off rollers 7,8, and the process is ended by returning the spinning-in device to its initial position.

During the spinning-in process, the feed offibrous material is controlled byafeeding device 15ofthe travelling service unit 1. The device 15 consists, by way of example, of a pull-out roller 47 having a rubber lining 48 which can engage the front face of the feed roller 49 ofthe spinning unit4so thatthe feed roller49isimmediatelycontrolled bytheservice unit 1 (Figure 2).

Figure 4 shows an alternative embodiment of the invention which distinguishes from the other embodiments in that each of the spinning units 4 is equipped with its own bobbin braking and lifting device 27 for stopping the thread winding just afterthe thread breakagewhiletheguidingductl6composed oftwo half-parts 38.1,39.1, takes over the thread below the take-off rollers 7,8. After a thread breakage, a detector (not shown) releases a signal to the electromagnet 37 which retracts it yoke 36whereby the pawl 34 disengages the safety pin 33.In this way the spring 32 is made free and swings, via the lever 31, the carrying arm 28 about the pivot 29 whereby, on the one hand, the pressure roller 8 is spaced apart fromthetake-offroller7and, on the other hand,the shoe 30 provided on the carrying arm 28 bears on the bobbin 11 and lifts it from the engagement with the driving drum 9. Thus the thread winding is effectively stopped and the thread remains hanging below the take-off rollers 7,8. Here it is then taken over by the guiding duct 16 as hereinabove described. The next phases of the spinning-in process take place analogously.

Similarly, the thread can be taken over, in lieu of the bobbin of the spinning unit, from an element of the travelling service unit such as, for example, atthe beginning of the spinning process when forthe spinning-in there is used a thread taken from a bobbin carried by the service unit itself.

Claims (8)

1. Ath read spi nni ng-in apparatus for use in an open-end spinning machine having a plurality of spinning units, comprising a control deviceforlifting and driving a bobbin as well as for spacing thread take-off rollers apart fro each other, and a thread guiding duct having an inlet mouth, a longitudinal slit and means for transferring thread to a thread take-offtubeofthespinning unit,whereinatleastthe lower partofthe thread guiding duct is formed as a thread spinning-in duct having thread transferring means intheform of an air-tightsocket adaptedto be put on thetake-offtube of a spinning unit, said spinning-in ductforming in its operative position an exten sion of said take-offtube with which it is connected during the spinning-in process through said air-tight socket.

2. Apparatus according to claim 1, wherein the inner diameter of at least lower part of the spinninginduct corresponds to the inner diameter of the thread take-offtube of the spinning unit.

3. Apparatus according to claim 2, wherein the spinning-in duct is composed of two coaxial tubes disposed one in the other and having each the longitudinal slit, at least one tube being rotatable and provided with a control arm coupled with a control device.

4. Apparatus according to claim 2, wherein the spinning-in duct is composed of two half-parts fac- ing each other and forming the longitudinal slit therebetween, one part being journalled about a pivot fixed in a carrier, and provided with the control arm coupled with the control device.

5. Apparatus accordingto claim 1,2,3or4, wherein the thread spinning-in duct is provided with a nozzle connected to a source of pressure air.

6. A thread spinning-in apparatus for use in an open-end spinning machine having a plurality of spinning units,the apparatus being constructed and adapted to operate substantially as herein before de scribedwith reference to Figures 1,2,3 and 6 of the accompanying drawings.

7. Apparatus according to claim 6 but modified substantially as hereinbefore described with referenceto Figure 4 of the accompanying drawings.

8. Apparatus according to claim 6 or7 but modified substantially as hereinbefore described with re ference to Figure5 ofthe accompanying drawings.