Process and apparatus for the propagation of rotation at the tie-in point of an open-end spinning apparatus

DESCRIPTION

[0001] The present invention concerns an apparatus in accord with the generic concept of claim 1 and concerns also a process which can be carried out with the aid of an apparatus of this type.

[0002] It is a matter of great importance in an open-end spinning machine, that at the point of thread entwinement, in which, during the thread formation process running fibers are forming into an open thread-end, that sufficient rotation is provided to avoid a break in the newly incorporated thread. To accomplish this, it is a generally conventional practice, to interpose a device into an open-end spinning element in which the thread is being made. This device, because of its structure and profiling, causes a periodic lifting of a thread, as it is being led through a thread-guide, at a change-of-direction surface of a thread intake element called, in its entirety, a thread withdrawal nozzle. This is done to enable the rotational twisting to propagate itself back to the entwinement point. Due to this profiling, however, the uniform twisting of the thread seized in the withdrawal nozzle at the entrance to the thread guide, or within the thread guide, is detrimentally affected by temporary restraint and subsequent release, with the result that the surface of the produced thread is roughened. In order to hold this undesirable side effect as small as possible, as a rule, in the thread guide, additionally a dummy rotator is provided, in order to increase the rotation, so that, upon the true rotation a false rotation is superimposed. On the grounds of the thereby increased rotation within the thread guide, the change-of-direction surface is to be more easily overcome. Further, the rotation which builds itself up from the true rotation and the false rotation can propagate itself better back to the fiber entwinement point.

[0003] The purpose of the present invention is to first, create a possibility of achieving a good rotational propagation to the open-end spinning element, and second, to provide a protective treatment of the thread on the other.

[0004] This purpose is achieved by the features of claim 1. Since the thread, upon its withdrawal in the course of its rotating in the thread guide, is not held back by a mechanical restraining element, wherein it would finally have to spring over the said restraining element, thus the thread is subjected to no high mechanical stress and its surface is not damaged. Much more, because of the oscillation imparted to the thread from the vibration element, the thread is periodically lifted from the thread contacting surface, so that the rotation during this phase can propagate without hindrance, or essentially so, in the direction toward the fiber entwinement point.

[0005] In principle, the thread contact surface can be an element independent of the thread guide, yet it has shown itself as advantageous, if this thread contact surface, as shown in claim 2, is part of the thread guide and the said surface is an integral part of the thread guidance system.

[0006] Since it is particularly important, that the twisting which forms in the thread guide propagates to the fiber entwinement point, in order to favor the fiber incorporation into the thread end, in an advantageous embodiment of the invented apparatus in accord with claim 3, provision has been made that the thread contact surface, which has been set into vibration, be found in the nearest possible location to the spinning element. To properly carry this out, the practical way is to design the thread contact surface in accord with claim 4.

[0007] An optimal release of the thread can be achieved by a development in accord with the invention, which follows claim 5.

[0008] It is true, that for the acquiring of special surface characteristics in the formed thread, now as before, it is possible to install a thread contact surface with a profiled face. Yet, however, for the object of the invention, which is the propagation of the rotational twisting, such a designed surface is not required and as a rule, a smooth outer surface design in accord with claim 6 is to be preferred.

[0009] Principally, any optional vibration drive for producing the oscillations can be applied, but an electromagnetic drive, in accord with claim 7 has shown itself to be particularly advantageous.

[0010] For the achievement of an optimal result, in regard to the character of the thread as it is made, in an advantageous improvement of the invented apparatus, in accord with claim 8, various degrees of oscillations can be selected. In connection with this, it is favorable for the simplification of the apparatus, if, in accord with claim 9, a system for the control of the vibration of a multiplicity of vibration elements is installed.

[0011] With the aid of the apparatus in accord with the invention, it becomes possible, not only to impart vibration to the thread, and thereby to improve the propagation of twisting, but moreover, this control system can be made to coincide with the current operational phase, in accord with claim 10. Thus, it is not a requirement, that during the start-up of spinning and during the normal production always one and the same vibration is brought to bear. Much more, for instance, during the start-up phase a defined vibration—perhaps with a lower frequency and a reinforced amplitude—can be brought into action on the thread. In this way, the twisting engendered in the thread guide can be transmitted in good order to the thread entwinement point. Subsequently, during the normal, undisturbed production another vibration characteristic is applied, since the vibration, in regard to frequency and amplitude is made to suit the altered spinning conditions, for example by increase of the frequency and amplitude. In a similar way, in accord with claim 11, the oscillation characteristic of the speed of rotation of the spinning element—i.e. of the rotating force therein—can be matched and/or made to suit the fiber material to be spun.

[0012] In the concept of the present invention, the idea “Rate of rotation of the spinning element” does not encompass only the RPM of a mechanical spinning element, but should, in many cases, also include the rotation speed of a pneumatic or electromagnetic vortex, which, actually, depends upon the individual design of the open-end spinning apparatus.

[0013] The object of the invention is simple in construction and effective in its function. With its aid, the twisting propagation to the entwinement point is improved, without a situation wherein the surface of the produced thread must suffer, since the thread, during its withdrawal in the longitudinal zone of the thread guide, as a rule passes therethrough over a predominately smooth surface. A false rotational element, on this account, can be dispensed with, insofar as the twist propagation to the entwinement point is concerned. Except in a protective treatment of the thread captured in the withdrawal, the special advantage of the invented process and the invented apparatus, above all, can be seen in that the twist propagation to the entwinement point is carried out independently of the rotational speed of the open-end spinning element. Further, the characteristics of the vibration, regarding frequency and amplitude can be chosen freely in accord with the desired spinning conditions. As said, the choice is independent of the rotational speed of the spinning element, and is independent of the medium or magnetic forcefield which rotates therein. In this way, the process and the apparatus of the present invention make possible the matching of the twisting propagation to the current operation phase, to the spinning fiber material and the ongoing operational speed. Thus, during the entire spinning procedure, in spite of different spinning conditions, always optimal relationships stand available to the propagation of the rotational twist.

[0014] Embodiment examples of the invention are explained below with the aid of the drawings. There is shown in:

[0015]
FIG. 1 a sectional view of an open-end spinning apparatus with a vibration device, in accord with the invention, for the threads, and also presents a schematic drawing the connections related to control, and

[0016]
FIG. 2 a portion of an altered vibration device in accord with the invention.

[0017] The apparatus in accord with the invention is explained in the following in connection with an open-end spinning apparatus 1, which possesses a spinning element 10 with a high speed, rotating spin-rotor.

[0018] The invention is not limited to one rotating spinning apparatus, but can also be employed in connection with open-end spinning apparatuses, which operate by a different open-end spinning principle. Examples of this would be an electrostatic open-end spinning apparatus with a circulating magnetic force, a pneumatic open-end spinning apparatus with a rotating air vortex or also a friction based spinning apparatus with one or more friction spinning elements. In all these open-end spinning apparatuses 1 is provided a thread withdrawal conduit 2 which serves a thread G during its exiting from, or out of, the spinning element 10. This thread withdrawal conduit is fastened to a holder, which, depending on the individual kind of the open-end spinning apparatus can be, or better, must be, of varied design. In the case of an open-end spinning apparatus built as a rotor-spinning machine, this said holder is formed by a rotor cover 3, which we will describe later.

[0019]
FIG. 1 shows, besides the spin element 10 which is constructed around a spin rotor in the particular embodiment, principally those components of an open-end spinning apparatus 1 which are necessary for full comprehension of the invention. In the case of the rotor spinning apparatus, which has been chosen as an embodiment, the spin element 10, i.e. the spin rotor, is arranged in a pot-like rotor housing, which, with the aid of a suction connection 12 is in communication with a vacuum source (not shown), so that the suction necessary for spinning can be created in the spin rotor.

[0020] The spin rotor possesses a rotor shaft 100, which extends itself through a corresponding opening 111 in the base 110 of the rotor housing 11. With the aid of this said shaft assembly, the spin rotor is supported in a conventional way and driven. Within that zone of the spin rotor with the greatest diameter, the spin rotor forms an annular fiber gathering surface 101.

[0021] The rotor housing 11, on its side remote from the base 110, is closed by the already mentioned rotor cover 3. This includes a fiber feed conduit 30, with which the spin rotor is supplied with fibers F which are to be spun. The thread G, which has been conventionally spun, exits from the spin rotor through the mentioned thread guide 2.

[0022] The rotor cover 3 possesses on the side proximal to the spin rotor, a female socket 31 into which a receiving element 31 is threadedly secured. Into the said receiving element 31 an exchangeable inlet element 21 is screwed. This inlet element 21, which in the case of rotor spinning machines, as a rule, is designated as a “thread withdrawal nozzle” and extends on into the rotor cover 3. In the axial connection to the inlet element 21, there is to be found a guide piece 22, which, in the case of the illustrated embodiment, is formed by a sheath-like insert. On the side remote from the spin rotor, a thread withdrawal tube 20 connects to the mentioned guide piece 22. The said withdrawal tube can be of optional shape and in a desired (not shown) version can be borne either by the guide piece 22 or by the rotor cover 3.

[0023] The inlet element 21, the guide piece 22 and the thread withdrawal tube 20 form together the mentioned guide 2 which, in relation to the movable rotor cover 3, is stationary.

[0024] The guide piece 22 possesses in its longitudinal extent, a lateral recess 220, through which a vibration element 40 penetrates, protruding into the interior of the guide piece 22. The vibration element 40 exhibits, in that area which protrudes into the interior of the guide piece 22, a smooth, thread contacting surface 41. On its end remote from the guide piece 22, the vibration element 40 possesses a solenoid shaft 42, which is circumferentially enclosed by a coil 43. The solenoid shaft 42, in this manner, is constructed as the armature of an electromagnet, which thus forms the drive 4 for the vibration element 40. The coil 43, with the aid of an angle iron 44 (or the like) is carried by the rotor cover 3. The coil 43 is connected by a line 50 with a control system 5.

[0025] The control system 5 can be made to serve only one open-end spinning apparatus. However, in accord with the example shown in FIG. 1, the control system is extended not only to the drive 4, that is, to the electromagnet, but also, in common, to vibration elements 40, 40a, 40b, 40c, 40d etc. These vibration elements, 40, 40a, 40b, 40c, 40d etc. are, for instance, located side by side in a common section of the open-end spinning machine.

[0026] During the spinning process, on a continuous basis, separate, individual fibers F are conducted through the inlet feed conduit 30 to the spinning element 10 which, in accord with the depicted embodiment in FIG. 1, is designed as a spin rotor. These fibers F deposit themselves in the spin rotor on the annular fiber gathering surface 101 thereof and are, in this place consolidated together, forming a fiber-ring R.

[0027] At an entwinement point E, the end of the thread G stands in connection with the said fiber ring R.

[0028] The thread G, which is formed, in a conventional way, by entwinement of the fibers F, is now, with the aid of means not shown, withdrawn in a continuous run from the spinning element 10 (spin rotor) and conducted further for windup on a spool (likewise not shown).

[0029] During the production of the thread G, the spin rotor is driven in conventional fashion at a high speed, so that the end of the thread G, which as said, is in contact with the fiber ring R, rotates likewise at a high rotational speed. In this manner, the radial thread section Ga. which extends from the entwinement point E to the inlet element 21 of the thread guide 2, acts as a crank arm and produces a true twisting rotation in the extending thread section Gb which section extends itself along the thread guide 2.

[0030] In order to be able to integrate the fibers F at the entwinement point E into the end of the thread G, which is in the course of formation, it is necessary that the said rotation brought about in the thread section Gb inside the thread guide 2, be propagated back as far as the entwinement point. This is made difficult, in that the thread G must change direction over a turning surface 210 formed on the inner contour of the inlet element 21, and, by doing so, adheres in some measure thereto.

[0031] In order to reduce this adhesive force, and thereby to make the desired rotation possible over the said turning surface 210, and extend all the way to the entwinement point E, the vibration element 40, with the aid of the coil 43 is set into oscillation. The thread G, which is found in the withdrawal tube, lies within the thread guide 2 with its thread section Gb on the thread contact surface 41 of the vibration element 40, so that the oscillation from the vibration element 40 is transferred to the thread G.

[0032] Because of this oscillation the thread G, in quickly repeated succession, is tensioned and again relaxed. During the relaxation phase, the twisting from the thread section Gb proceeds into the thread section Ga and thereby to the entwinement point E. Because of this rotation propagated to the entwinement point E, the fiber ring R, by means of the end of the thread section Ga which is now rotating, binds itself into this said end.

[0033] The apparatus described above in construction and function can, within the framework of the invention, be altered in multitudinous ways, particularly by the exchange of single or several features or through other combination of features or their equivalents. Thus, for example, it is not required to lift the thread G from the turning surface 210 by a vibration acting transverse to the longitudinal extent of the thread guide 2. That is to say, to so reduce the pressure of the thread G against the turning surface 210, that the rotation over the said turning surface can extend itself to the to the entwinement point E. A corresponding embodiment of the previously mentioned apparatus is described in the following, based on the embodiment shown in FIG. 2, wherein the oscillation is produced in a direction parallel to the longitudinal axis A of the thread guide 2.

[0034] In the case of the embodiment shown in FIG. 2, the thread is not set into vibration at any point within the guide 2, but this is effected immediately at the entrance of the inlet element 21. To carry out this purpose this inlet element 21 is screwed into a receiving element 320, which, of its own, can be brought into vibration and thus can serve as a vibration element 40. In doing this, the change of direction surface 210 functions simultaneously as the thread contact surface 41 of the vibration element 40. A drive 4 is connected to the receiving element 320, which is constructed as a movable part of the otherwise stationary thread guide 2 seated in rotor cover 3. This drive 4, in the embodiment shown in FIG. 2 is again designed as an electromagnet. For this purpose, the receiving element 320 possesses an arm 321 extending outward in a radial direction, with which the solenoid shaft 42, serving as armature of the electromagnet, is connected, which, on its own, in the described manner, is connected by electrical line 50 to the control system 5 (see FIG. 1). The coil 43 is carried by means of an angle iron 440 (or the like) extending from the rotor cover 3.

[0035] Where this above described construction of the thread guide 2 is concerned, the thread contact surface 41 is formed by a movable part of the thread guide 2, namely, by the inlet element 21. Even in the case of such a design of the apparatus, the rotation propagation is thereby improved, in that the thread G, in the neighborhood of the entry end of the thread guide 2, which end is proximal to the spin rotor, is periodically lifted from the turning surface 210. In this manner, the twisting rotation is enabled to be propagated from its point of origin in the interior of the thread guide 2 back to the entwinement point E, and thereby a fault-free entwinement of the fiber ring R into the end of the thread section Ga is assured.

[0036] It is indeed of advantage, but yet not necessarily required, that the inlet element 21—as has previously been described—be set into vibration in an axial direction. Alternatively, provision can be made, that the arm 321 continues on into the solenoid shaft 42, which is designed as an armature of an electromagnet, which shaft protrudes essentially perpendicularly to the longitudinal extension of the inlet element 21 and that of the thread guide 2. Even in the case of a design of this kind of the thread guide 2 and of the vibration element 40, a periodic release of the thread G is attained, so that even here a good and assured propagation of the rotation in the direction of the entwinement point E is achieved. An advantageous provision would be, that oscillatory motion can be induced both in an axial direction and as well as transverse to the longitudinal extent of the inlet element 21.

[0037] In a particularly advantageous embodiment of the invention, provision can be made, to construct an armature shaft 42 operating in conjunction with a coil 43 within a combination inlet element 21 and thread withdrawal nozzle. In this way, by means of the coil in connection with the shaft 42 which enters the withdrawal nozzle, this assembly can be located and held in the in an open-end spin apparatus, to the advantage that other holding means, such as retaining screws, can be dispensed with.

[0038] While, in accord with the previously known state of the technology, where a rotational motion propagation to the entwinement point E was concerned, it was taken as a necessary evil, that in the inlet element 21 or in the thread withdrawal tube 20, or yet again at another place within the thread guide 2, the thread G would be subjected to a severe mechanical loading, in the described apparatus, it is not necessary to have the thread G undergo such stress. It is entirely possible, and as a rule to be preferred, that the contact surfaces, which the thread G touches within the thread guide 2, exhibit a smooth surface, even like the thread contact surface 41 of the vibration element 40. Should, however, a definite contouring of one or more such surfaces be desired for other reasons, for instance in order to lend the thread G a bulgy appearance, then, naturally, there is nothing in the present design which would stand in the way of such adaption. Such surfaces can then, without consideration of the desirable propagation, be formulated solely on the basis of the desired character of the thread in regard to the appearance thereof.

[0039] Principally, it is advantageous, in the case of the described apparatus, to have the thread G simply passing over surfaces with high polish. Moreover, except in cases of protective treatment of the thread G while in the withdrawal means, it is of especial advantage for the invented process and apparatus, to assure, that the rotational propagation to the entwinement point E is carried out independently of the rotational speed of the open-end spinning element and that the type of vibration in regard to frequency and amplitude can be freely optionally selected. This will be described in the following.

[0040] In an open-end spinning apparatus 1, the start of the thread is a sensitive procedure, independent as to whether it is a first time onset of the sprinning operation after a long stillstand, or whether the matter concerns startup after a thread break. This procedure is done, accordingly, by the present day high rotational speeds of the spinning elements 10, that is, of a spin rotor, during the top RPM of the same or in the case of a reduced speed, as compared to normal operation. When speed is reduced, the action on the thread section Ga is thus not so much due to high centrifugal force, as is the case during normal operation.

[0041] In order to assure acquiring a reliable entwining of the fiber ring R into the end of the thread section Ga, provision can be made, that during this time the rotational propagation to the entwinement point E is optimized by a corresponding matching of the generation of the vibration to meet the special demands in force during a current operational phase. This can be done, for instance, by an increase of the frequency and/or the amplitude. In a case wherein the amplitude has been increased, the rotational propagation under certain circumstances can also be improved, in that the frequency is reduced, relative to that of the normal spinning operation. From this it is clear, that by the change of one of these values, or both, optimal conditions which have been empirically determined as best for each operational phase can be brought about.

[0042] A change of the frequency and/or the amplitude is of advantage not only because of being fit to a certain operational phase. Also, by the working of different fiber materials, which correspondingly required different spinning conditions, and upon different rotational speeds of the open-end spinning apparatus, the current spinning conditions can be optimized by corresponding adjustment of the character of the vibration.

[0043] In the simplest design of the apparatus, the control system 5 provides only a single definite frequency and only one definite amplitude for the vibration element 40. An improved design of the control system 5 is shown in FIG. 1. The control system 5 shown there as one embodiment possesses a first regulation device 51 which has an adjusting knob 510, a scale 511 as well as four display fields 512, 513, 514 and 515. The control system 5 exhibits further, in accord with the shown embodiment, a second regulation device 52 with an adjustment knob 520, a scale 521 as well as four display fields 522, 523, 524 and 525. The first regulation device 51 serves for the adjustment of the desired frequency, while the second regulation device 52 allows for the adjustment of the amplitude.

[0044] The adjustment knobs 510 and 520 are, in accord with the shown embodiment, designed as being multifunctional. Thus, for example, provision has been made, that by the activation of the adjustment knobs 510, 520, respectively, the value of the frequency or the amplitude can be set to the desired degree.

[0045] First, these values would be set for the initial operational phase, that is, spinning startup, which is respectively shown in the first display field 512, 522. By pressing the adjustment knob 510, 520, a switchover to the next operational phase is effected, that is, the normal run of the spinning process. This is shown in the second display field 513, 523. Also, respectively, the desired value can be obtained by the turning of the knob 512, 520. Further adjustment possibilities are possible by switching onto the further display fields, respectively 514, 515 and 524, 525.

[0046] Other designs of the respective regulation device 51, 52 are obviously possible. Also, further presetting possibilities can be provided by corresponding extension of developments in the control system 5.

[0047] It is plain to see, that principally the vibration to the thread section Gb can be transmitted at any optional location within the thread guide 2, however, experience has shown, that it is advantageous, if this is done in the nearest possible location to the entry end of said thread guide 2, that is, as close as possible to the area of the entry element 21. The true thread rotation induced by the thread section Ga functioning as a crank forms itself in the subsequent longitudinal zone of the thread guide 2 which adjoins the change of direction, or turning surface 210. In this way, the contact of the thread section Gb on the thread contact surface 41 of the vibration element 40 so acts, that the propagation of the twisting in the direction to the thread withdrawal tube 20 is retarded. In this way, the rotational twisting which propagates itself in the direction of the entwinement point E can be just so much more intensive, the smaller the distance is chosen between the turning surface 210 and the thread contact surface 41.

[0048] As the present explanation indicates, the rotational twist is thereby propagated to the entwinement point E in such a manner, that the thread G is brought into oscillation and thereby periodically lifts itself from the turning surface 210.

[0049] The special mode of the design of the drive 4 for the generation of vibration and the distribution of the same is of no relevant importance. Those designs thereof in the illustrations are thus simply embodiment examples.

[0050] Instead of the shown construction of the drive 4, it is also possible to produce the vibrations by purely mechanical means. For instance, cams can be provided on a shaft, which direct, or with an interposed vibration element, (similar to the shown vibration element 40) can be caused to effect the thread G. By means of an exchange of said cam for a cam of another size or shape, the shape of the vibration and/or amplitude can be changed, while by the RPM determined for the cams the vibration frequency can be controlled. It is also possible, in the area of the guide piece 22, that is, at a specified distance from the turning surface 210, by means of interposing a membrane or another appropriate intervening element for instance wherein a tube or a bellows forms a part of the thread guide 2 in a portion of its longitudinal section which makes the movable part thereof. This can be, for example, a pulsating pneumatic medium for the generation of the oscillations

Process and apparatus for the propagation of rotation at the tie-in point of an open-end spinning apparatus

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CPC

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Priority Claims (1)