Patent Publication Number: US-6662542-B2

Title: Open-end spinning device and process for temporary receiving a yarn

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an open-end spinning device as well as to a process for the temporary receiving of a yarn by means of such a device. 
     With open-end spinning devices, it is normal practice to have a service unit patrolling alongside a plurality of identical open-end spinning devices so as to be able to perform maintenance tasks at each one of these open-end spinning machines when necessary. For this purpose, the service unit is, as a rule, provided among other things with a yarn suction pipe that can be brought from a resting position within the contours of the service unit into a working position in which it is located in close proximity of the yarn path (DE 196 34 300 A1). This yarn suction pipe has, e.g., the task of preparing a length of yarn for the piecing return feeding and of temporarily storing yarn excess produced during piecing, until it is used up due to the difference in speeds between a device drawing the pieced yarn from the spinning element and the bobbin. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is a principal object of the present invention to further develop the known suction device and to create a process for the temporary receiving of a yarn by means of such a device, so that it becomes possible for the device to handle additional tasks. Additional objects and advantages of the invention will be set forth in part in the following description or may be obvious from the description, or may be learned through practice of the invention. 
     This object is attained through the invention by having the yarn suction pipe movable within at least one additional operating plane. Due to the fact that the yarn suction pipe can be moved not only within one single operating plane but can be brought out of it and into at least one additional operating plane and can be moved within that plane, the yarn suction pipe is capable of carrying out tasks in a further operating plane offset in time relative to tasks to be carried out in a first operating plane. 
     Preferably, the operating planes, of which at least two are provided, of the yarn suction pipe are placed at an angle relative to each other so that they form an angle between them. By “angle,” an angle value is understood as being greater than zero and smaller than infinite. 
     In a further development according to the invention, the resting position of the yarn suction pipe is provided in proximity of the interface of two operating planes of the yarn suction pipe and/or is provided only in one single operating plane. This results in space-saving advantages. 
     Preferably, the operating positions are established in two operating planes that take into account the traversing range of the yarn traversing guide. This makes possible a soft transfer of the yarn to a traversing guide in one operating plane when the full bobbin is set on the winding roller, while in the other operating plane the yarn extending from the yarn guide to the bobbin driven by the winding roller is not within the traversing range of the traversing guide. 
     In a further development according to the invention of the open-end spinning device, the yarn suction pipe can be controlled by a control device in accordance with a previously prepared program, so that it is taken into one of the operating planes provided to carry out the operating movements for that operating plane. 
     For various tasks to be carried out by the yarn suction pipe, it suffices if it can merely be taken from its rest position into one single operating position. However, in order for the yarn suction pipe to be able to handle more complex tasks, it is an advantage if the yarn suction pipe is also able to assume several operating positions, one after the other, in at least one of its operating planes. 
     In the interest of a simple design, the yarn suction pipe can be mounted on a swivel pin so that it can be swiveled. 
     The movement of the yarn suction pipe from one operating plane to another operating plane can be effected in various ways, e.g., by moving it along a guiding system. In a preferred embodiment of the device according to the invention, it is possible to provide for the yarn suction pipe to be movable along its swivel pin or around an additional swivel pin supporting the swivel pin of the yarn suction pipe into an additional operating plane. It may be advantageous to install this additional swivel pin essentially parallel to the axis of the winding roller. 
     The apparatus described above makes it possible to carry out a process according to the invention in adaptation to different operating phases of the operating process. The yarn suction pipe is brought into the corresponding operating plane in a sequentially synchronized manner, in which it then carries out its operating movements provided for this operating plane and this operating phase. In this manner, the yarn suction pipe can carry out operating movements different from the ones carried out at other locations, and can thus carry out completely different tasks. 
     In another variant of the process, the yarn suction pipe is brought into the same operating plane to receive the yarn drawn off from a bobbin, independent of the operating plane to be occupied for the execution of certain operational movements. 
     According to a further embodiment of the invention, the yarn suction pipe can execute the operating movements required for the formation of a piecing reserve or the temporary storing of a yarn surplus occurring briefly during piecing in the same plane in which it had previously taken up the yarn presented to it. In order to constitute a yarn end reserve on the full bobbin, the yarn suction pipe can be transferred from the operating plane in which it had previously taken up the yarn drawn off from a bobbin into another operating plane in which it imparts its operational movements. 
     The device as well as the process according to the present invention makes it easily possible for one and the same yarn suction pipe to carry out entirely different tasks at different times. At the same time, the design of the device is simple and space-saving, since, instead of a plurality of yarn suction pipes with the appertaining terminals and their controls, only one single such yarn suction pipe is required for a number of different tasks. 
    
    
     Examples of embodiments of the invention are explained below through drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a schematic lateral view of a device according to the invention with a yarn suction pipe that can be placed at will in one of two operating planes; 
     FIG. 2 shows a top view of a bobbin and of a yarn suction pipe interacting with it; 
     FIG. 3 shows a lateral view of a controlled yarn suction pipe according to the invention together with its drives and a control device; and 
     FIG. 4 shows a modified embodiment of the driving apparatus of the yarn suction pipe. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are shown in the figures. Each example is provided to explain the invention, and not as a limitation of the invention. In fact, features illustrated or described as part of one embodiment can be used with another embodiment to yield still a further embodiment. It is intended that the present invention cover such modifications and variations. 
     FIG. 1 schematically shows an open-end spinning machine  1  indicated by a broken line on the left side of the drawing, while a service unit  2  is indicated on the right side of the drawing by means of a dot-dash line. The service unit  2  is able to patrol in a known manner alongside the open-end spinning machine  1 , which has a plurality of identical open-end spinning devices  10 . Of the open-end spinning machine  1  as well as of the service unit  2 , only those elements that are necessary to understand the invention are shown in the FIGS. 1 to  4 . For this reason, only a known yarn suction pipe  100  of an open-end spinning device  10  of this type is shown in FIG.  1 . 
     The open-end spinning machine  1  is furthermore equipped with a yarn draw-off device  11  with a draw-off shaft  110  which extends over a plurality of identical, adjoining open-end spinning devices  10 . During the drawing off of a yarn F from the open-end spinning devices  10 , a pressure roller  111  presses against this draw-off shaft  110  and can be lifted off from the draw-off shaft  110  when necessary. 
     The yarn F drawn off by the yarn draw-off device  11  from the open-end spinning devices  10  is conveyed to a winding device  12  equipped with a winding roller  120  that also extends over a plurality of adjoining open-end spinning devices  10 . A bobbin  121  lies on the winding roller  120  during the spinning process in order to wind up the yarn F produced in the open-end spinning device  10 . The bobbin  121  is held in a known manner between two bobbin arms  122  and  123  (see FIG. 2) by means of rotatably mounted bobbin plates (not shown), whereby the bobbin arm  122  has a lifting arm  124 . 
     During the spinning process, the yarn F is traversed by a yarn traversing guide  126  located before the bobbin  121  as seen in the direction of yarn movement (see arrow f 1 ), so that the yarn F is laid down evenly over the length of the bobbin  121  (bobbin body) during winding. To ensure nearly constant yarn tension of the yarn F during this operation, a yarn tension equalization hoop  127  is installed within the course of the yarn before the yarn-traversing guide  126  in the direction of draw-off (see arrow f 1 ). 
     A swiveling suction pipe  20  is located on the service unit  2  and can be swiveled from the shown resting position until it is in proximity of the bobbin  121 . 
     In addition, a presentation device  21  is installed on the service unit  2  that can be brought from a lower end position  21   a  indicated by a full line into an upper end position  21   b  by swiveling around a swivel pin  210 . This presentation device  21  has a swiveling yarn catcher  211  at its free end. 
     In proximity of the swiveling range of the yarn catcher  211  is a controllable clamping device  220  which is part of a yarn feeder  22 . This yarn feeder  22  can be brought from a starting position indicated by a full line into a second position  22   a  above the outlet opening  101  of the yarn draw-off pipe  100 . 
     In the area of the lower end position of the presentation device  21 , a yarn end preparation device  23  exists. 
     The service unit  2  is further equipped with an auxiliary roller pair  24  with a stationary roller  240  and a driven roller  241  which can be presented to the roller  240 . 
     In addition, a reserve hoop  25  by means of which a piecing reserve A can be constituted and which swivels around a swivel pin  250  is located on the service unit  2 . 
     In addition, a yarn suction pipe  3  of which FIG. 1 only shows the area with its outlet  32  is provided on the service unit  2 . This yarn suction pipe  3  is mounted on a pin  40  so as to be able to swivel (see FIG. 3) and can execute operating movements as desired within a first plane E a  or a second operating plane E b  or can be moved into different operating positions  3   b ,  3   c  or positions  3 A,  3 B,  3 C (see FIG.  2 ). The yarn suction device  3  is connected to a hose  31  that is in turn connected to a negative-pressure source in a controllable manner not shown here. 
     As a comparison between FIGS. 1 and 2 shows, it is not important whether a cylindrical or conical bobbin  121  is being formed. The described device and also the described process can be applied independently of the shape of the bobbin  121  being formed. 
     The structure of the device was described above, and now its operation during piecing following stoppage of the open-end spinning device  10  shall be described with the help of FIG.  1 . For example a yarn breakage has occurred, and the bobbin  121  has therefore been lifted from the winding roller  120  by raising the lifting arm  124  (FIG. 2) and has thus been stopped. 
     In order to resume the spinning process, a piecing process must be carried out. For this, the suction pipe  20  is first swiveled from its resting position shown in FIG. 1 towards the bobbin  121 . Furthermore, an auxiliary drive roller (not shown) is brought to bear on the bobbin  121 , by means of which the bobbin  121  is driven in unwinding direction (arrow f 3 ). Because of the negative pressure prevailing in the suction pipe  20 , this suction pipe  20  takes up the yarn end located on the bobbin  121  and sucks it up to the extent that it becomes available through the reverse rotation of the bobbin  121 . As soon as the suction pipe  20  has taken up a long enough yarn segment to ensure secure holding of the yarn F, the suction pipe  20  is swiveled back into its starting position while the bobbin  121  is at first still driven in unwinding direction (see arrow f 3 ), so that the suction pipe  20  continues to take up the length of yarn released by the bobbin  121  until the bobbin  121  is stopped by the (not shown) auxiliary drive roller. 
     The yarn suction pipe  3  that has been until then in its resting position  3   a  in a first operating plane E a  (see FIGS. 1 and 2) is brought within this first operating plane E a  with its outlet  32  into the operating position  3   b  shown in FIG. 1 by swiveling it around its pin  40 . In this position, the yarn F passes the zone of the outlet  32  of this yarn suction pipe  3  during the further operating phases, as shall be explained further below. 
     By means of the (not shown) auxiliary drive roller, the bobbin  121  is driven in winding direction (arrow f 2 ) for a short time. Since the bobbin  121  is in lifted position and the yarn F connected to the bobbin  121  extends to the suction pipe  20 , the path of the yarn does not cross the movement range of the yarn traversing guide  126 . Thereby, parallel windings are produced on the bobbin  121 , and these are located at a defined location relative to the longitudinal extension of the bobbin  121  due to a corresponding (not shown) configuration of the outlet of the suction pipe  20 . A defined yarn path results in this case between the bobbin  121  and the suction pipe  20 . 
     At the latest at that point in time, the presentation device  21  is swiveled around its swivel pin  210  from its lower end position  21   a  into its upper end position  21   b , whereby the swiveling path of the presentation device  21  is located outside the path of yarn F extending from the bobbin  121  to the suction pipe  20 . When the presentation device  21  is in its upper end position  21   b , the yarn catcher  211  located at the free end of the presentation device  21  is actuated and is moved into such a position that it seizes and takes along the yarn F during the following downward swiveling motion of the presentation device  21 . This yarn F forms a loop (not shown) between the bobbin  121  and the suction pipe  20 . The length of yarn necessary for the formation of the loop is withdrawn from the suction pipe  20  in this process. 
     As the presentation device  21  is swiveled down into its lower end position  21   a , the yarn F reaches the nip of the clamping arrangement  220  of the yarn presenter  22 , where it is fixed by clamping. At its leading end relative to the down-swiveling movement, the presentation device  21  is supporting a yarn cutting device (not shown) that is now actuated. The yarn segment freed thereby and extending to the suction pipe  20  is removed through the suction pipe  20 . 
     The presentation device  21  continues its down-swiveling movement and takes the yarn end produced by cutting into the zone of influence of the yarn end preparation device  23  where it releases the yarn end. The yarn end is now held by the yarn end preparation device  23  that puts the yarn end in a known manner into a state that is suitable for the piecing process to be carried out. 
     The bobbin  121  is now driven by means of the (not shown) auxiliary drive roller in unwinding direction (arrow f 3 ), whereby the yarn length freed from the bobbin  121  is taken up by the yarn suction pipe  3  which had already been brought into the path of the yarn as described earlier. When the yarn segment stored in the yarn suction pipe  3  has reached a predetermined length, a piecing reserve A is constituted by swiveling the reserve hoop  25  into yarn F. The length of yarn required for this is taken from the yarn suction pipe  3 . 
     The yarn presenter  22  is then taken out of its starting position indicated by a full line into its position  22   a  in which the free yarn end is within the area of influence of the air stream entering the outlet opening  101  of the yarn draw-off pipe  100 . This air stream is produced in a known manner inside the open-end spinning device. The yarn suction pipe  3  brought into the path of the yarn compensates for differences in yarn length that occur in this case. 
     During the movement of the yarn presenter  22  into its position  22   a , the yarn F comes into contact with the roller  240  of the auxiliary roller pair  24 . The second roller  241  is now applied on the roller  240  so that the yarn F is in the nip of this auxiliary roller pair  24 . 
     The release of the lifting arm  124  causes the bobbin  121  to be lowered so that it is again applied to the winding roller  120 . The bobbin  121  is again driven in the winding direction (arrow f 2 ) by the winding roller  120 , thus winding up the yarn F from the yarn suction pipe  3 . The driving of the bobbin  121  can at first be assisted also by the (not shown) auxiliary drive roller that continues to be applied to the bobbin  121 . 
     Before the lowering of the bobbin  121  on the winding roller  120 , the yarn F extending from the bobbin  121  to the yarn suction pipe  3  is located above the yarn tension equalization hoop  127  and outside the movement range of the yarn-traversing guide  126 . However, the lowering of the bobbin  121  causes the yarn F to enter this movement range and the path of the yarn-traversing guide  126 . The latter thus receives the yarn F and forms windings crossing each other on the bobbin  121  as the yarn is wound up on it. At this point in time, the yarn F is not yet within range of the yarn tension equalization hoop  127 , nor is this necessary, since the bobbin  121  is able to draw off the yarn length needed for winding from the yarn suction pipe  3  without change of the yarn tension of the yarn F. 
     The yarn length temporarily stored in the yarn suction pipe  3  is monitored by a yarn monitor (not shown). The reserve hoop  25  is actuated as a function of the yarn length inside the yarn suction pipe  3  and thereupon releases the piecing reserve A. This actuation can be effected by swiveling the reserve hoop  25  or by throwing off from the same in a known manner. 
     The released yarn F comes into contact with fibers that are fed to a known spinning element of the open-end spinning device  10 , so that the spinning process can be started by renewed withdrawal of the yarn F from the open-end spinning device  10 . The auxiliary roller pair  24  now driven in draw-off direction withdraws the yarn. 
     When the piecing reserve A is released, the yarn F is applied to the draw-off shaft  110 . The pressure roller  111  is now placed on the draw-off shaft  110  so that the yarn draw-off device  11  on the machine draws off the yarn F from the open-end spinning device  10  from then on. The auxiliary roller pair  24  is now no longer needed. For this reason, the driven roller  241  is lifted off from the other roller  240  of the auxiliary roller pair  24 . 
     Because of the large mass of the yarn F wound up on it, the bobbin  121  cannot be accelerated as rapidly as the pressure roller  111  placed on the draw-off shaft  110 . Therefore, a yarn surplus is created between the yarn draw-off device  11  and the bobbin  121  and is taken up by the yarn suction pipe  3 . 
     At the right moment the roller  240  also releases the yarn F in a known manner, whereby the yarn surplus created by a shortening of the path caused by the release of the yarn is also taken up by the yarn suction pipe  3 . 
     The yarn suction pipe  3  is then moved from its operating position  3   b  into its operating position  3   c  (FIG.  1 ). This reduces the magnitude of the yarn deflection. When the yarn F temporarily stored in the yarn suction pipe  3  is used up in spite of the continuous feeding of the yarn F by the yarn draw-off device  11 , the yarn path is shortened again since the yarn F is now applied against the yarn tension equalization hoop  127 . 
     It is possible to dispense in certain cases with an additional operating position  3   c  when the operating position  3   b  of the yarn suction pipe  3  is properly defined for the reception of a yarn surplus. In such cases, a somewhat greater drop in tension, causing a certain disturbance in the bobbin build-up must be accepted briefly for the transfer of the yarn F to the yarn tension equalization hoop  127  as the yarn surplus stored in the yarn suction pipe  3  is used up as a result of the shortening of the yarn path. For this reason, more than just one single operating position  3   b  (see operating position  3   c ) of the yarn suction pipe  3  is provided with the above-described embodiment. 
     The yarn suction pipe  3  has taken up the yarn F in the operating plane E a , readied the yarn F so that the reserve hoop  25  could constitute a piecing reserve A, and temporarily stored the yarn surplus produced momentarily during piecing. When this temporarily stored yarn surplus has been used up, the yarn suction pipe  3  has accomplished its task pertaining to the piecing process. It is returned then into its resting position  3 a without having left the operating plane E a  during piecing. 
     Once all the elements and aggregates of the service unit  2  have again returned to their resting positions within the contours of the service unit  2 , the service unit  2  leaves the open-end spinning device  10  upon successful piecing in order to work at another open-end spinning device  10  now requiring service. 
     The service unit  2  is not only able to carry out a piecing process, but it can also replace bobbins or perform other maintenance tasks, e.g., cleaning, etc. 
     As an example of an additional service task in which the yarn suction pipe.  3  is used, the forming of a yarn end reserve R is described below. Such a yarn end reserve R is to be generated on a full bobbin  121  before doffing of the bobbin (see tube  125 ). 
     The operational steps up to the reception of the yarn F by the yarn suction pipe  3  are the same as described previously in connection with piecing. Here too, the yarn suction pipe  3  takes up the yarn F for as long as the yarn suction pipe  3  is in its first operating plane E a , even if subsequent operational steps are carried out in a second operating plane E b . 
     When the yarn end which has been cut by means of the cutting device assigned to the presentation device  21  is located in the yarn suction pipe  3 , the auxiliary drive roller drives the bobbin  121  in the unwinding direction (see arrow f 3 ) causing a sufficient yarn length to be delivered into the yarn suction pipe  3  for the operational steps described below, whereupon the bobbin  121  is stopped. The yarn-suction pipe  3  is then moved from its operating plane E a  into another operating plane E b . The manner in which this movement is accomplished is explained further below. 
     To avoid the necessity of reserving a large area for the space to be traversed by the yarn suction pipe  3  during this movement of the yarn suction pipe  3  from the first operating plane E a  into the second operating plane E b , the resting position  3   a  is provided in the closest possible proximity of the interface S between the two operating planes E a  and E b . 
     When it has reached the operating plane E b , the yarn suction pipe  3  is brought into a first operating position  3 A before an end of the stopped bobbin  121 . The latter is now again driven in wind-up direction (see arrow f 2 ) by being brought into contact with the winding roller  120 . The yarn suction pipe  3  which is in operating plane E b  assumes such a position in its operating position  3 A that the yarn F extending from the yarn suction pipe  3  to the bobbin enters neither the movement range of the yarn traversing guide  126  nor the area of the yarn tension equalization hoop  127  even though the bobbin  121  is pressing on the winding roller  120 . Thus, parallel windings W 1  are formed in wind-up direction (see arrow f 2 ) on a circumferential area U 1  of the bobbin body while the bobbin  121  is driven, whereby two or three such windings W 1  suffice. The yarn suction pipe  3  is then moved beyond the adjoining edge  128  of the bobbin  121  to its operating position  3 B, while the bobbin  121  continues to be driven in wind-up direction. The circumferential area U 2  on which the yarn F is now wound to produce a yarn end reserve R consisting of one or several windings is no longer within the longitudinal area of the bobbin  121  but outside of same, in the area of tube  125 . Once the desired number of windings of the yarn end reserve R has been formed here, the yarn suction pipe  3  is brought into operating position  3 C in the circumferential area U 3  of the bobbin  121 , where one or more parallel windings W 2  are again produced. 
     As the description above shows, the yarn suction pipe  3  can be brought into more than only one single operating position  3 A,  3 B or  3 C also in operating plane E b . Furthermore, the windings W 2  can in some cases also cover the windings W 1 , even though FIG. 2 shows two windings W 1  and W 2  at two different locations of the bobbin  121 . This is achieved in that the operating positions  3 A and  3 C are selected so that they coincide. 
     In synchronization with the formation of the yarn end reserve R, the yarn F extending towards the yarn suction pipe  3  is cut in a suitable manner (not shown). The yarn suction pipe  3  is equipped for instance with a cutting device at its outlet or in proximity thereof, which is able to carry out this task. Furthermore, the bobbin  121  is stopped by lifting off the winding roller  120  upon formation of the yarn end reserve and the return of the yarn F on the bobbin body. The full bobbin  121  can now be replaced by an empty tube  125 . 
     The yarn suction pipe  3  has carried out its task and returns into its resting position  3   a  in the first operating plane E a . Upon the return of all the elements to their resting positions, the service unit  2  can leave the open-end spinning device  10  it has just serviced. 
     As described earlier, the bobbin  121  lies on the winding roller  120  during the movement of the yarn suction pipe  3  from its operating position  3 A into its operating position  3 B. Thereby any negative influence of this operational movement of the yarn suction pipe  3  upon the already formed windings W 1  is avoided. Therefore, the contact position of the bobbin  121  on the winding roller  120  during this operational movement of the yarn suction pipe  3  results in a defined transition from the parallel windings W 1  into the yarn end reserve R, because the yarn excursion executed in the direction of the end of tube  125  cannot affect the parallel windings W 1  beyond the nip between the bobbin  121  and the winding roller  120 . However, the contact position of the bobbin  121  on the winding roller  120  is not absolutely necessary for the formation of the windings W 1  themselves, so that in principle it suffices if the bobbin  121  is brought into contact with the winding roller  120  only at the beginning of the above-mentioned yarn excursion for the formation of the yarn end reserve R. On the other hand, the application of the full bobbin  121  on the winding roller  120  causes the windings W 1  and W 2  to be rolled in to a certain degree due to the contact pressure of the bobbin  121  on the bobbin surface. The windings W, and W 2  being rolled into the bobbin is an advantage for the retention of the yarn end on the bobbin  121 . In connection with this, improved retention occurs since the bobbin body has a certain surface roughness because of the hairiness of the yarn F. In this manner, the end of the yarn F deposited here in the form of one or several windings W 2  is effectively secured, even during subsequent handling in the course of transportation and in further treatment in a yarn processing textile machine, e.g., a knitting or weaving machine. 
     In principle, it does not matter at which end of the bobbin  121  the yarn end reserve R is formed. Since in subsequent further processing of the yarn F wound up on a conical bobbin  121  the yarn is pulled off from the bobbin on the side with the smaller diameter, it is advantageous to provide the yarn end reserve R at this bobbin end. 
     According to the above description, the yarn suction pipe  3  executes different operational movements in a defined manner in the two operating planes E a  and E b . These operational movements of the yarn suction pipe  3  are controlled by a control device  6  that also interacts with a transfer device  4  (see FIG. 3) by means of which the yarn suction pipe  3  can be moved from the first operating plane E a  into its second operating plane E b  and back. 
     As FIG. 4 shows, the control device  6  can be programmed in a suitable manner. Adjusting knobs  64  are used to program, for example, whereby the adjustments made can be displayed on a display  65 . Additionally, or alternatively, a possibility for the insertion of a data support (chip, CD Rom, etc) by means of which the control device is suitably programmed can also be provided, so that the piecing process and other tasks can be carried out in the desired manner during the different operational phases. In this case, the yarn suction pipe  3  is brought successively into the corresponding operating planes E a  and E b  in which it carries out the corresponding operational movements in a predetermined time sequence by following the program of the control device  6  as a function of these operational phases. 
     As has been described, the yarn suction pipe  3  is brought into the first operating plane E a  based on the predetermined program in order to constitute a piecing reserve A. In this operating plane E a , a possibly occurring yarn surplus can also be received. To constitute a yarn end reserve R, however, the control device  6 , on basis of its predetermined program, causes the yarn suction pipe  3  to be brought into its second operating plane E b  in which the yarn suction pipe  3  carries out the necessary operational movements. 
     The previously mentioned transfer device  4  (FIG. 3) has a swivel pin  40  to which the yarn suction pipe  3  is non-rotatably connected. The swivel pin  40  is connected to a swivel drive  41  which may be designed in form of a stepping motor. This swivel drive  41  of the yarn suction pipe  3  is in turn mounted on a holding device  42  which is pivotably mounted on a shaft  43 . The holding device  42  is made in the form of a two-arm lever, whereby a piston rod  440  of a pneumatic or hydraulic drive cylinder  44  is connected to the free end of this lever via a coupling element  441 . 
     The drive cylinder  44  is connected to a control valve  5  via lines  50  for the arrival or removal of the control medium. The control valve  5  controls the arrival of the control medium into or removal of the control medium out of the drive cylinder  44 . No detailed drawing of the control valve  5  or of the line  50  have been provided for sake of clarity, and because such controls are sufficiently well known. 
     The control valve  5  as well as the swivel drive  41  is connected via control lines  61  and  60 , respectively, to the above-mentioned control device  6  which controls the piecing process, the replacement of a full bobbin  121  by an empty tube  125 , and other processes such as cleaning of the open-end spinning device  10  or details thereof. 
     As FIG. 3 clearly shows, the yarn suction pipe  3  that is presented in FIG. 3 to the bobbin  121  (not shown) is either in the operating plane E a  in which the yarn suction pipe  3  takes up the yarn F presented to it as described above and in which it also temporarily stores a yarn surplus produced during the piecing process, or it is in the operating plane E b  in which the yarn suction pipe  3  presents the yarn F to the bobbin  121  so that a yarn reserve R may be produced on it, depending on the swivel position of the holding device  42 . To transfer the yarn suction pipe  3  from the operating plane E a  into the operating plane E b  or from the operating plane E b  into the operating plane E a , the holding device  42  is swiveled correspondingly under the control of the control device  6 , the control valve  50 , and the drive cylinder  44 . Independent of the swivel position of the holding device  42  and therefore of the operating plane E a  or operating plane E b  occupied by the yarn suction pipe  3 , the yarn suction pipe  3  is always swiveled around the same swivel pin  40  to be transferred into the resting position  3   a  or the operating position  3   b ,  3   c ,  3 A,  3 B, or  3 C. 
     The described device as well as the described process are not limited to the embodiment mentioned, but can be modified in many ways under the present invention, in particular through the replacement of individual characteristics by equivalents as well as through different combinations of the characteristics or of their equivalents. Thus, it is not necessary for the operating planes E a  and E b  to include a sharp angle a as shown in FIGS. 1 and 3. Placing the two operating planes E a  and E b  at different angles relative to each other is perfectly possible. Thus, it is possible to bring the yarn suction pipe  3  into a third operating plane (not shown) extending, e.g., parallel to the plane of the drawing in addition to the two mentioned operating planes E a  and E b  in order to take over the task of the presentation device  21  in this third operating plane. In this third plane, for instance, the yarn suction pipe  3  can take up the yarn F extending from the bobbin  121  to the suction pipe  20  through suitable control of the negative pressures in the suction pipe  20  and in the yarn suction pipe  3 , and convey it to the clamping device  220  of the yarn presenter  22  as well as to the yarn end preparation device  23 . Upon release of the yarn F, the yarn suction pipe  3  can be returned from this (not shown) third operating plane into its previously mentioned operating plane E a  to be placed in the operating position  3   b  shown in FIG. 1 where it then carries out the described tasks. 
     To make it possible for the yarn suction pipe  3  to carry out the different tasks and to be brought into the operating planes E a  and E b  provided for these tasks, it may be necessary under certain conditions that the transfer device  4  be provided with a pin in addition to the swivel pin  40  and the pin  43 . 
     In the embodiment described above, it is also possible to transfer the yarn suction pipe  3  by means of a transfer device designed in a similar manner as those described above through FIG. 3 from one operating plane E a , E b  . . . into another. For reasons of space availability, it is generally advantageous with such a design of the device if the resting position  3   a  of the yarn suction pipe  3  is always in just one of the operating planes E a , E b  . . . provided. 
     As shown in FIG. 3, the pin  43  around which the holding device  42  can be swiveled is essentially parallel to the longitudinal axis of the open-end spinning machine  1  and of its shafts, such as the winding roller  120  or the draw-off shaft  110 . This is especially advantageous if the yarn suction pipe  3  is also to take over the traversing of the yarn F along the bobbin  121  in addition to its storing tasks. Nevertheless, it may be advantageous under certain conditions to place the pin  43  at an angle to the longitudinal axis of the open-end spinning machine  1 , e.g., to ensure, whatever the form of the bobbin  121  (conical or cylindrical) may be, that the yarn suction pipe  3  can always be brought with its outlet  32  into the closest possible proximity of the tube  125  and/or the bobbin end on which the windings W 1  and W 2  are formed. 
     As the embodiment of FIG. 4 shows, it is also possible to provide operating planes E A  and E B  for the yarn suction pipe  3  which are not at an angle a relative to each other but are parallel to each other. The yarn suction pipe  3  is for example installed non-rotatably by means of a hub  30  on a swivel pin  70  of a transfer device  7 , e.g., by means of a hub-and-spring combination. The swivel pin  70  in the embodiment shown has an arm  71  extending radially to the outside, to the end of which a pin  72  and an intercalated coupling element  731  connects the piston rod  730  of a drive cylinder  73 . The control medium is conveyed to the drive cylinder  73  or is removed from it by means of lines  74 . These lines  74  are controlled suitably by means of a control valve  51  that is connected via a control line  63  to the control device  6 . 
     The hub  30  by means of which the yarn suction pipe  3  is mounted on the swivel pin  70  furthermore contains a connection bore (not shown) connected to the yarn suction pipe  3 , and through it a hose  31  or a mobile or mounted pipe is connected to the negative-pressure source (not shown) to establish the connection between the yarn suction pipe  3  and the negative-pressure source. On its outer circumference, the hub  30  is provided with a circumferential groove  300  into which a fork-shaped lifting element  75  enters. The end of this lifting element  75  away from the hub  30  is supported by the free end of a piston rod  760  of a drive cylinder  76  that is connected via lines  77  to the control valve  52 , the latter being in turn connected via a control line  62  to the control device  60  for control. 
     With the described transfer device  7 , the yarn suction pipe  3  is moved by means of the suitably controlled drive cylinder  76  along its swivel axis  70  into the desired operating plane E A  or E B , while the yarn suction pipe  3  is placed in its currently required swivel position by means of a suitably controlled drive cylinder  73 . 
     The yarn suction pipe  3  can also be shifted between its operating planes E a , E b , . . . or E A , E B  . . . by means of transfer devices that are designed differently from the shown embodiments (transfer device  4  or  7 ). It is, for example, also possible to mount the yarn suction pipe  3  in a connecting link (not shown) so that it can be shifted, whereby the connecting link may also follow an irregular course, depending on the tasks to be carried out by the yarn suction pipe  3 . Such a connecting link can be provided for the transfer from one operating plane into another operating plane, as well as for the movement of the yarn suction pipe  3  within one operating plane. The transfer operations described above apply similarly to the use of a curved path on which a guiding element of the yarn suction pipe  3  and/or of the transfer device  4  or  7  is pressed by means of an elastic or similar element. 
     According to the embodiments described above the yarn F that is presented to the yarn suction pipe  3  is taken from the bobbin  121  that is in the winding device  12 . The operational steps required to present the yarn F to the yarn suction pipe  3  can however deviate from the operational steps provided for this and described above. 
     It is not an absolute necessity for the described process or for the device used for it that the yarn F to be taken up by the yarn suction pipe  3  is taken from bobbin  121  on the machine. The traveling service unit  2 , for example, can also carry a bobbin (not shown) from which the yarn F required for piecing can be drawn. On the occasion of a bobbin replacement, this yarn F is then presented to the yarn suction pipe  3  in connection with these operational steps. 
     It will be appreciated by those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope of the invention. It is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents.