EP0531507A1 - Process and device for joining a thread spinning in an open-ended spinning machine - Google Patents

Abstract

In order to join the thread (20) in an open-end spinning device (11) provided with a thread gathering surface (17), a thread ribbon (2) is brought to the lining of a cylinder covered with teeth (141), which separates the wires (22) and directs it in this form to the surface (17) for collecting the wires, where the wires are linked to the end of a wire brought back which is then pulled continuously. The anterior end of the ribbon of wires (2), which forms a beard (21), is brought to the toothed covered cylinder (141) with a depth of penetration greater than the depth of penetration after the junction of the wire, while the wire is joined by spinning in the usual way, in accordance with the reduction in the depth of penetration. The penetration depth is sharply reduced to prevent thickening in the junction of the wire. In order to implement the method, a device (4) for adjusting the penetration depth is controlled by a control device (30).

Description

 Method and device for spinning a thread in an open-end spinning device

The present invention relates to a method for spinning a thread in an open-end spinning device having a fiber collecting surface, in which a fiber sliver is fed to the clothing of a disintegration roller and dissolved by it to fibers and in this form fed to the fiber collection surface where the fibers are bound into the end of a returned thread, which is then continuously drawn off, and a device for carrying out this method.

The problem with piecing is that, on the one hand, the returned thread end and the supplied fibers form an overlap point which forms a thick point in the piecer. On the other hand, the thread must be accelerated to the production take-off speed. If this acceleration takes place too slowly, a thick point is also generated in the piecing device. If, on the other hand, this acceleration takes place too quickly, there is a risk of thread breaks due to the high withdrawal tension. To solve these problems, it is known from WO 88/10990 to determine the combed state of the fiber beard and to adapt the thread draw to the effect of the fiber feed on the fiber collecting surface. Furthermore, it is known from this document to begin thread withdrawal with a slight acceleration before the fibers reach the fiber collecting surface, and only after contact has been made the fibers then fed to the fiber collecting surface with the thread end to increase the thread take-off. In this way, an extensive reduction of the thick point in the piecer can be achieved, but the piecer is still disruptive for certain purposes.

The object of the present invention is therefore to create a method and a device with the aid of which the piecing device can be formed even more inconspicuously.

This object is achieved according to the invention in that the leading end of the sliver forming a fiber beard is fed with a penetration depth for the spinning on of the opening roller which is greater than the penetration depth later after the spinning, while the spinning on in a conventional manner in coordination with a reduction in the depth of penetration. By changing the depth of penetration of the fiber beard, the ratio between fiber feed and thread take-off is changed briefly in comparison to the corresponding conditions before and after this change in the fiber beard penetration depth, so that temporarily fewer fibers get onto the fiber collecting surface. The result is that the point in the thread corresponding to this fiber deposit turns out to be thinner than usual, so that thick points can be counteracted in this way.

This reduction in the penetration depth is distributed over time so that the fiber is fed onto the fiber quilt at the beginning of the reduction in the penetration depth of the fiber beard into the clothing of the opening roller. In this way, the reduction in the penetration depth counteracts the usual thick spot caused by the overlap of the thread end and newly fed fibers, so that thick spots are minimized.

In order to achieve a thread thickness that corresponds to the desired thread thickness not only in the narrower piecing area, but also subsequently, the thread draw-off is expediently controlled in adaptation to the start of the fiber feed onto the fiber collecting surface reduced by the reduction in the depth of penetration of the fiber beard .

According to a further advantageous development of the method according to the invention, it is provided that the thread draw-off begins before the depth of penetration of the fiber beard into the clothing of the opening roller is reduced. As a result, an even better compensation of an otherwise possible thick spot in the piecing device is achieved with a simultaneous gentle acceleration of the thread take-off.

In order to be able to adapt the thread take-off behavior to the start-up behavior of the fiber feed, the state of the fiber beard at the start of the piecing is advantageously determined and the start and / or the acceleration course of the thread take-off are adapted to the state of the fiber beard in such a way that with a more combed-out fiber beard the thread draw later begins and / or starts with a lower acceleration than with less combed fiber beard.

The reduction in the penetration depth is particularly effective if, in accordance with a further expedient development of the method according to the invention, the procedure is that the fiber beard, on the one hand, at least approximately in an equilibrium state between combed fibers per unit of time, immediately before it moves back from the increased penetration depth and on the other hand with the fibers fed to the fiber.

It has proven to be advantageous if the difference between the increased penetration depth and the reduced penetration depth after piecing is chosen such that a thread thickness reduction of at least 10% takes place immediately after the abrupt return movement of the fiber beard into the reduced penetration depth. However, the difference is preferably chosen so that the thread thickness reduction is between 10 and 30%.

A particularly effective avoidance of excess fibers, which usually lead to thick spots in the piecing, can be achieved by suddenly reducing the depth of penetration of the fiber beard into the clothing of the opening roller.

A procedure according to the invention has proven to be particularly favorable in terms of device and control, according to which will maintain the reduced depth of penetration of the fiber beard into the clothing of the dissolving salts for production.

If the greater depth of penetration of the fiber beard into the clothing of the opening roller is that depth of penetration that the fiber beard also assumes during production, so that the reduced depth of penetration is only provided temporarily for the fiber beard, then in a further embodiment of the method according to the invention provides that the depth of penetration of the fiber beard into the clothing after being spun on is increased again to the initial value and this depth of penetration is then maintained for production. In this way, thin spots that would otherwise occur after the piecing can be minimized. If changes in the number are to be avoided, since no such thin point is to be compensated, then after the reduction in the penetration depth the fiber feed has again at least substantially assumed the value corresponding to the production, the penetration depth can be increased slowly that the amount of fibers combed out by the opening roller per unit of time practically does not change during the penetration depth increase.

In principle, the control of the depth of penetration of the fiber beard into the clothing of the opening roller can be controlled in various ways, but it has proven to be particularly advantageous if the fiber beard is exposed to a controllable air flow for this purpose. For pneumatic control of the depth of penetration of the fiber beard into the clothing of the opening roller, it is advantageously provided that in order to increase the depth of penetration after the area in which the fiber bit is fed to the opening roller, a depression is brought into effect which corresponds to that after Piecing exceeds effective negative pressure.

While it is possible to let the elevated negative pressure acting in the area of Fasersammeifläche, but it has proved to be particularly advantageous, the is supplied to the region at which the tuft of the opening roller ^', wir¬ kenden increased negative pressure at a location such to bring about effect on which the fibers have not yet reached the fiber collecting surface.

In order to prevent fibers which were impaired during the standstill of the open-end spinning device in question from getting onto the fiber collecting surface and from being incorporated into the returned thread end during spinning, it is expedient to reduce the fibers to the To remove the penetration depth of the fiber beard without first having reached the fiber collection surface and only to feed the fiber collection surface when the penetration depth is reduced.

According to the invention, it can be provided in a simple manner that the reduction in the negative pressure acts by switching off an air flow exceeding the spinning negative pressure and switching on a weaker one on the fiber collecting surface. the air flow takes place.

In order to achieve a particularly effective minimization of thick spots, it is provided in a further advantageous embodiment of the method according to the invention that the depth of penetration is not only reduced as suddenly as possible, but also by as large a value as possible by reducing the vacuum effect until the point in time of reduction The depth of penetration of the fiber beard into the clothing of the opening roller is kept at a value which ensures the increased depth of penetration and is significantly higher than the pressure after the piecing.

According to the invention, for the sake of simplicity, the depth of penetration is increased by switching on and the depth of penetration of the fiber bit is reduced by switching off an air flow.

As already mentioned, the pneumatic control of the depth of penetration of the fiber beard into the clothing of the opening roller is particularly expedient, but it is also entirely possible to control the depth of penetration mechanically. For this purpose, it can be provided that the change in the penetration depth of the fiber beard is carried out by adjusting a feed device or a part thereof that feeds the sliver of the opening roller. According to a further advantageous, alternative development of the method according to the invention, the depth of penetration of the fiber beard can also be changed by adjusting a mechanical guide surface which leads between the fiber sliver to the opening roller Feed device and the opening roller is provided.

To carry out the method, according to the invention, a penetration depth changing device which controls the penetration depth of the fiber beard into the clothing of the opening roller is provided, which is connected in terms of control to the control device and with which by changing the penetration depth of the fiber beard into the clothing of the opening roller Fiber flow to the fiber collecting surface can be influenced.

In order that an abrupt effect of a change in the penetration depth of the fiber beard into the clothing of the opening roller and thus in the fiber flow can be achieved, the penetration depth changing device can advantageously be abruptly adjusted in at least one of the two changing devices. The penetration depth changing device is preferably designed as a penetration depth increasing device, which can suddenly be deactivated.

The penetration depth change device is preferably controlled pneumatically, wherein according to an advantageous embodiment of the subject matter of the invention, the penetration depth change device has an overpressure source which is connected to the control device for control purposes and which opens into the housing of the opening roller in the length region of the fiber beard.

According to an alternative, likewise advantageous embodiment of the device according to the invention, the penetration depth Change device a negative pressure source which is connected to the control device in a control manner and can be brought into effect in the housing of the opening roller.

According to a further advantageous development of the subject matter of the invention, it can be provided that the negative pressure source assigned to the fiber collecting surface and the negative pressure source serving as an actuating device together form the penetration depth changing device and can be brought into effect overlapping. If the two negative pressure sources overlap, an increased negative pressure is generated, which pulls the fiber beard more strongly into the clothing of the opening roller and, when switched off, allows the fiber beard to return to its less deep penetration position.

The penetration depth change device can preferably be brought into effect in the fiber transport path between the feed device and the fiber collecting surface.

In principle, the vacuum source can open into the opening roller housing at various points, e.g. in an end wall, but according to the invention it is preferably provided that the vacuum source is connected or can be brought into connection with a suction air opening provided in the peripheral wall of the housing of the opening roller.

According to an advantageous embodiment of the subject matter of the invention, the suction air opening is arranged in the length region of the fiber beard, wherein it is expediently covered by a sieve so that the fibers are not sucked off. In order to be able to collect suctioned fibers, a fiber collecting container is expediently provided between the suction air opening and the vacuum source.

In order to be able to enlarge the jump between the two extreme penetration depths of the fiber beard, in a further advantageous embodiment of the device according to the invention, the suction air opening can optionally be connected to the vacuum source and an overpressure source, the vacuum source in one setting and the other in the other setting Ren setting of the penetration depth change device the positive pressure source is brought into effect.

Regardless of whether the penetration depth is controlled by overpressure or underpressure, the overpressure or underpressure source can be connected to the interior of the opening roller, which has a perforated outer surface.

In an alternative advantageous embodiment of the subject matter of the invention, the negative pressure or positive pressure source can open into a feed trough forming part of the feed device and can be directed essentially radially against the clothing of the opening roller.

If a maintenance device which is movable along a multiplicity of similar open-end spinning devices is provided for the piecing, then the control device and - in the case of a pneumatically designed adjusting device - the adjusting device for the penetration depth changing device are expediently arranged on this maintenance device - net.

In the case of a mechanical design of the penetration depth changing device, it is expediently provided that the penetration depth changing device has an adjusting device for the feed device or a part thereof or an adjustable guide surface arranged in the area of the fiber beard.

So that the thread take-off can be optimally adapted to the fiber feed effective on the fiber collecting surface, it is advantageous if a device which is connected to the piecing device for determining the state of the beard at the beginning of the piecing process and which is connected to the control device is provided is. In this case, the device for determining the state of the fiber beard is expediently connected via the control device to the timing element for the penetration depth changing device.

With the aid of the method and the device according to the present invention, it is possible to achieve short-term changes in the amount of fiber feed effective on the fiber collecting surface, in order to compensate for and thereby minimize thick or thin spots in the thread. By appropriate time control of the change in the penetration depth with which the fiber beard of the clothing is fed to the opening roller, it is possible to specifically counteract a technologically determined thick or thin point in the piecing machine or in the subsequent thread break. there the solution is simple both in terms of structure and control. It can also be easily installed in existing machines.

Several exemplary embodiments of the invention are explained below with the aid of drawings. Show it:

FIG. 1 shows a schematic side view of an open-end spinning device with a penetration depth changing device according to the invention;

FIG. 2 shows a side view of a depth of penetration change device which presses the fiber beard into the clothing of the opening roller with an increased depth of engagement;

3 shows a side view of the device shown in FIG. 2, which presses the fiber beard into the clothing of the opening roller with a reduced engagement depth;

FIG. 4 shows a side view of another embodiment of the penetration depth changing device according to the invention;

FIG. 5 shows a schematic comparison of a conventional piecer and a piecer according to the invention, as well as the required fiber beard position and the through fiber flow generated;

Figure 6 shows a schematic representation of the start-up diagrams of fiber feed and thread take-off;

FIG. 7 shows a schematic illustration of a piecing device produced by the method according to FIG. 6 and the subsequent piece of thread;

FIG. 8 shows a modified design of fiber feed and thread take-off;

FIG. 9 shows a schematic representation of the piecing device produced by a method according to FIG. 8 and the piece of thread adjoining it;

Figure 10 shows a fiber feeding and dissolving device with a modified penetration depth changing device in cross section;

FIG. 11 shows the fiber collecting surface of a spinning rotor with a fiber ring and a fade end deposited thereon in a schematic representation during the piecing phase; and

FIG. 12 shows a modified connector according to the present invention in a schematic representation. First of all, the device for carrying out the method is to be described with reference to FIG. 1 as far as is necessary to explain the problem to be solved.

1 shows in its left half a schematic representation of a spinning station 10 of an open-end spinning machine 1. Each spinning station 10 has an open-end spinning device 11 and a winding device 12.

The open-end spinning device 11 shown works with spin elements designed as spinning rotors 110, but the invention can also be used with other open-end spinning machines, e.g. Use friction spinning machines with advantage. Correspondingly, the fiber collecting surface 17 of the spinning element is formed by the inner circumferential groove of the spinning rotor 110 or a wedge gap of friction rollers or the like, which depends on the choice of the spinning element.

Each open-end spinning device 11 has a feed or delivery device 13 and a dissolving device 14 for feeding a sliver 2. In the exemplary embodiment shown, the delivery device 13 consists of a delivery roller 130 with which a feed trough 131 cooperates elastically. The feed trough 131 is pivotally mounted on an axis 132.

The opening device 14 in the embodiment shown in FIG. 1 is essentially as one in a housing. se 140 arranged, provided with a clothing 143 opening roller 141. A fiber feed channel 111 (see mouth 117) extends from it to the spinning rotor 110, from which a spun thread 20 is drawn off through a thread draw-off tube 112. This opens coaxially z, around the spinning rotor 110 into a housing 113 which surrounds the spinning rotor 110.

To generate the required spinning underpressure is connected to the Gehäu¬ se 113, a vacuum line connected to 114, which via a switching device (switching valve ^'115) and a Faser¬ tanks 118 in the form of a filter with an underpressure source is connected 116th The switching device (switching valve 115) is connected to a control device 30 for control purposes via a line 300.

In addition to this first vacuum line 114, a second vacuum line 18 connected to the open-end spinning device 11 is provided. This second vacuum line 114 ends in a suction air opening 180 which - seen in the direction of fiber transport (arrow f ₂ ) - between the mouth 117 of the fiber feed channel 111 and the delivery device 13 outside the fiber transport path in the peripheral wall 142 of the housing 140 for the opening roller 141 is provided. This second vacuum line 18 is also connected to a vacuum source 32 via a switching device 181 and a vacuum line 321. The vacuum source 32 (or a shut-off valve assigned to it) is connected via a line 320 in control with the control device 30. A fiber collecting container 182 in the form of a filter is also provided at a suitable point in the vacuum line 321, through which the sucked-off fibers 22 would be separated.

For the withdrawal of the yarn 20 during the undisturbed Spinn¬ process from the spinning rotor 110 is a pair of delivery rollers 15 with a driven at production speed Ab¬ zugswalze 150 and a resiliently zugswalze on the driven Ab¬ 150 adjacent and entrained by the ^'ser Ab¬ zugswalze 151 intended. On its way between the open-end spinning device 11 and the pair of draw-off rollers 15, the thread 20 is monitored by a thread monitor 16.

The withdrawn thread 20 then passes to the winding device 12, which has a driven winding roller 120. The spooling device 12 also has a pair of pivotable spool arms 121, which hold a spool 122 between them. The bobbin 122 lies on the winding roller 120 during the undisturbed spinning process and is consequently driven by it. The thread 20 to be wound onto the bobbin 122 is placed in a traversing thread guide (not shown) which is moved back and forth along the bobbin 122 and thereby ensures a uniform distribution of the thread 20 on the bobbin 122.

Along the open-end spinning machine 1 and its multitude A similar type of open-end spinning device 11 can be used to move a maintenance device 3, which carries the mentioned control device 30 for controlling the piecing process. This is connected via a line 312 to the drive 310 of a swivel arm 31 which carries an auxiliary drive roller 311 at its free end. The auxiliary drive roller 311 is driven by a drive motor (not shown) which is also in control connection with the control device 30 (not shown). This auxiliary drive roller 311 drives the bobbin 122 for the return of the thread 20 for piecing and can also serve to carry out the piecing take-off until this take-off has been accelerated to the production speed and the further thread take-off by the Puller roller pair 15 is taken over.

Swivel arms (not shown) can be added to the spool arms 121, which are likewise pivotably mounted on the maintenance device 3 and whose swivel drive is in a control connection with the control device 30. These pivot arms raise the spool arms 121 for piecing so that the spool 122 is separated from the spooling roller 120 and can be driven by the auxiliary drive roller 311. After the piecing process has ended, the bobbin arms 121 are lowered again, so that the bobbin 122 is driven again by the bobbin roller 120 (in time coordination with the takeover of the thread take-off by the take-off roller pair 15). To release a piecing thread reserve, which is formed in the returned thread during preparation of the piecing process, a discharge spindle 33 is provided, the drive (not shown) of which is connected to the control device 30 via a line 330 for control purposes.

In the undisturbed spinning operation, the fiber sliver 2 is fed to the dissolving device 14 by means of the delivery device 13, ideally dissolved up to individual fibers (fibers 22) and fed in this form to the fiber collecting surface 17 of the spinning rotor 110. The fibers 22 are deposited there briefly and then incorporated in a known manner into the end of a thread 20 which is being drawn and which is drawn out of the open-end spinning device 11 through the thread take-off tube 112 with the aid of the pair of draw-off rollers 15. The thread 20 leaving the draw-off roller pair 15 is fed to the winding device 12 and wound onto the bobbin 122.

If, for any reason, a thread break occurs, this is registered by the thread monitor 16 and via a control connection (not shown) of the control device 30 or a control unit (not shown) which cooperates with the control device 30 (eg central control unit on the open-end spinning machine 1) reported. At the same time, the thread monitor 16 turns off the delivery device 13 in a manner known per se. The control device 30 or the control unit cooperating with the control device contains a timer, not shown, which starts to run when the thread breakage is reported. If a further thread break occurs at another spinning station 10 while this timer is running, a further timer starts to run. Through the running time of these timers, the period between the occurrence of a thread break and the beginning of the thread break repair can be determined.

During the maintenance device 3 the open-end spinning machine

I runs along, it asks via a line (not shown) whether the spinning station 10 which it reaches next works properly or whether a thread break at this spinning station 10 can be remedied. If a thread break is to be re-spun at this spinning station 10 in order to remedy a thread break, the maintenance device 3 stops and initially carries out preparatory work. This includes e.g. braking the spinning rotor 110, cleaning the open-end spinning device

II or some parts thereof, lifting the bobbin 122 off the winding roller 120, locating the end of the broken thread 20 on the bobbin 122, pulling off a thread length sufficient for spinning from the bobbin 122 while simultaneously driving the bobbin 122 by means of the auxiliary drive roller 311, the preparation of the thread end, the laying of the thread on the ejection spindle 33 during the insertion of the thread end into the thread take-off tube 112 and the run-up of the spinning rotor 110 to production speed. speed,

These processes are controlled in a known manner by the control device 30. Once this preparatory work has been completed, the actual .spinning can begin.

From the point in time at which the maintenance device 3 is locked at the spinning station 10 until the end of the piecing process, all work steps are precisely timed, whereby different time sequences can be individually pre-set as desired in accordance with the material, thread size, etc. .

While the delivery device 13 is at a standstill when the opening roller 141 continues to run, this further combs fibers 22 out of the leading end of the stopped fiber sliver 2, the so-called fiber beard 21, so that it is shortened and thinned. The longer the standstill time of the delivery device 13 (always with the dissolving device 14 continuing to run), the shorter the fiber beard 21 until, during a long standstill period, no more fibers 22 protrude into the working area of the opening roller 141. These different states of the fiber beard 21 result in different run-up behavior of the fiber feed.

Corresponding to the downtimes of the delivery device 13 when the opening roller 141 continues to run and the resulting different states of the fiber beard 21 with regard to the release of the sliver 2 by switching on the delivery pre-activation, the thread take-off should be switched on earlier (with less impairment of the fiber beard 21 due to less downtime) or later and faster (with less impairment of the fiber beard 21) or less. For this reason, at the beginning of the piecing process, the state of the fiber beard is determined (as a function of time or in another way) and the start and / or the acceleration course of the thread take-off is adapted to this state of the fiber beard 21 in the manner described.

5 a) shows the piecing devices P _a , P _b and P _c when the delivery device 13 has been idle for different lengths of time with the opening roller 141 continuing and then uncontrolled release of the sliver 2 by switching on the delivery device 13. The normal rate is 100% Thread size marked.

When the delivery device 13 is at a standstill, relatively little fiber material is combed out of the fiber beard 21 by the opening roller 141, so that the fiber supply to the fiber collection surface begins almost suddenly in full intensity. The result is a very strong piecing P _a , which not only exceeds the normal thickness of the thread in the overlap region of the thread end E _G (see FIG. 7) and fiber ring R _F (length section A _L ), but also the entire length of the thread Circumference U of the spinning

REPLACEMENT LEAF includes tors 110 and which is followed by a long thread section A _{a of} excessive thickness.

A particularly short piecing device P _b results when the delivery device 13 is at a medium standstill when the opening roller 141 continues to run. This piecing device P _b already has the normal thread size after the thread length corresponding to the circumference U of the spinning rotor 110.

In the event of a very long downtime, the fiber beard 21 is both combed out and shortened. As a result, on the one hand it takes longer for the sliver 2 to reach the working and effective range of the clothing 143 of the opening roller 141 and for the fiber stream to enter the spinning rotor 110 (or another spinning element). And when it finally starts, the fiber stream is initially very thin and takes a relatively long time to reach its full production value. As the piecer P _c shows, the section A _L is still slightly reinforced in its first length range, but its diameter is then already reduced. Such a reduced length section can be found not only in the length area corresponding to the peripheral area of the spinning rotor 110, but also in the thread section A ₌ adjoining it.

6 using a typical example (mean downtime of the delivery device 13 between the response of the thread monitor 16 and the switch-on time t _{L of} the delivery device 13):

6 shows the time t on the abscissa, while the ordinate shows the speed in percent (%) of the respective production values.

If the delivery device 13, which was previously shut down when a yarn breakage occurs, is put into operation again at the switch-on time t _L , the sliver 2 is fed to the opening device 14 again. With a delay, which is due to the time required to generate a fiber stream again between the delivery device 13 and the open-end spinning element, for example the spinning rotor 110, the fiber feed resumes on the fiber collecting surface of the spinning rotor 110 (see time T _x ). The period of time within which the fiber flow (based on the fiber collection surface) again reaches its full value also depends on the downtime of the delivery device 13 with the opening roller 141 continuing to run. The period of time is characterized in FIG. 6 by the time T _λ for the beginning of the fiber flow and T for reaching the full fiber flow (100% - based on the fiber collection surface).

6 shows - highly schematically - the natural run-up curve of the fiber feed F _b , as it becomes effective on the fiber collection surface. This run-up curve arises after switching on the delivery device 13, if not from the outside intervening in the drive of the delivery device 13, but instead by simply switching it on, it is connected to a drive running at production speed or when the delivery device 13 running at production speed is brought back into effect if this drive was not interrupted beforehand but by lifting off the feed trough 131 had only been deactivated by the delivery roller 130. This natural run-up curve develops depending on the state of combing and thus varies accordingly.

The thread take-off G _b is adapted to the condition of the fiber beard 21. The take-off acceleration is selected so that the thread take-off G _b reaches its production value (100%) substantially simultaneously with the fiber feed F _b . In this case, the thread 20 (with a slight impairment of the fiber beard 21) with a short delay (see time T ₃ ) compared to the release of the fiber sliver 2 (see switch-on time t _L ) quickly changes to the same percentage speed value as the fiber feed F _b brought (see acceleration phase G _b , and time T ₄ ), to then run up synchronously with this (see acceleration phase G _b2 ). The transitions are fluid, which, however, has not been taken into account in FIG. 6 due to the simplicity of the illustration.

For the sake of clarity, the reproduction of the thread return has been forgiven in FIG. 6. It takes place after

REPLACEMENT ATT Switching on the delivery device 13 at such a time that after a desired or after an unavoidable dwell time on the fiber collecting surface, the thread draw G _b can take place in the manner shown.

If the fiber feed begins on the fiber collecting surface before the thread take-off G _b begins, a fiber accumulation forms on the fiber collecting surface, which in the case of the spinning rotor 110 selected as an example takes the form of a fiber ring. This creates a thick spot D _{x in the} piecer (see FIG. 7), which is shown in FIG. 6 by the times T 1. , T _Λ and T ₃ defined triangle DRj is shown. The greater the distance between the times T ₁ and T ₃ and the flatter the acceleration curve of the thread take-off in the acceleration phase G _b . is, the greater is this fiber accumulation which causes this thick spot.

In addition to the acceleration _phases G _b _ and G _b _, an acceleration _phase G _{b20 is also} shown in _dash- dot lines in FIG. 6, which results when the acceleration of the thread take-off G _b until the production take-off speed is reached (time T ₅ ) ( 100%) remains unchanged. Then, from the time T ₄ to the time T ₂ , the thread take-off G _{b is} faster than the fiber feed F _b onto the fiber collecting surface, so that a thin point D ₂ (see FIG. 7) is created in the thread 20, as shown by the times T ₄ , T ₅ and T ₂ defined triangle DR _{2 is} shown.

REPLACEMENT LEAF Before the piecing which occurs in the run-up curves of fiber feed F _b and thread take-off G _b is described in more detail, FIG. 11 will explain what happens when the fiber ring R _? happens that has formed on the fiber collecting surface 17 of a spinning element designed as a spinning rotor 110.

The time difference (T ₃ - T _t ) (FIG. 6) indicates how much the thread take-off G _b starts later than the fiber feed F _b . The greater this time difference, the larger the fiber ring R _F forming in the spinning rotor 110, while the smaller this time difference, the smaller it is.

It is assumed that a thread break should be repaired. After the usual preparatory work (cleaning the spinning rotor 110, searching for the thread end E _G on the bobbin 122 (FIG. 1), cutting to length and preparation of the thread end, releasing the previously stopped spinning rotor 110 etc.), the fiber feed F _b ( Time T _:) released, which now runs up to its production value (100%) and in the spinning rotor 110 a fiber ring R _? forms. Matched to this startup of the Fa¬ serzufuhr the Fasersammeifläche the yarn end E _G on the Fasersammeifläche of the spinning rotor is delivered back 110, whereby the yarn end E _G in the direction of rotation of the Spinnro¬ gate 110 (see the arrow f.) Over a part of the circumference U of The fiber collecting surface 17 deposits (see also FIG. 7) and its radial intermediate region Z _G assumes the position Z _{G :} . After a short dwell time on the fiber collecting surface, the thread end E _{G is} subjected to the thread take-off G _b , which also runs up to its production value (100%). The thread end E _{G is} tensioned and reaches the position Z _G2 with its intermediate area Z _G. The thread end E _G pulls on the fiber ring R _F so that, viewed in the circumferential direction of the fiber collecting surface 17, fibers extend from the thread end E _G to the fiber ring R _F on both sides from the binding point P _E and fiber bridges B _F and B _{F 2} form. When the thread take-off G _{b is continued} , the intermediate region Z _{G of} the thread end E _{G reaches} the position Z _{G 3} . The fiber bridges B _F and B _F _ tear and wind in the form of wild windings W around the thread end E _G. The size of this fiber bridge B _F _ and thus the size of the accumulation of turns W essentially depends on the rotor diameter and the length of the fibers processed.

A piecer P produced by the method according to FIG. 6 has the appearance shown schematically in FIG. 7 (compare piecer P _c in FIG. 5 a)). The yarn end E _G returned to the spinning rotor 110 on its fiber collecting surface is deposited over a partial area of the circumference U of the fiber collecting surface 17 (FIG. 11) after a partial fiber ring has already formed in the spinning rotor 110 (FIG. 1). Until the thread take-off G _b begins, further fibers 22 are deposited in the spinning rotor 110, which form a fiber ring R _F with the fibers 22 fed into the spinning rotor 110 before the thread is returned (see FIG. 5 b): 100% up to section A _L ). The Fa The quantity of water corresponds to the triangle DR ₃ shown between the times _: and T ₃ in FIG. 6.

When the thread take-off G _b is inserted, the fiber ring R _F is torn open, not only fibers are bound into the thread end E _G which, with respect to the binding point P _E, face on the side facing the free end of the thread end E _G ( Arrow f _: - fiber bridge B _F ,), but also fibers from the other side of the tie-in point P _E (fiber bridge B _{F 2} ) • These fiber bridges B _B and B _F2 thus reach the position of the piecer as a wrap W P, at which the fiber ring R _{F is} blown open (Fig. 7 left). The piecer P thus begins at the time T ₃ with a very strong cross-sectional jump.

In this first length section A _{L of} the piecer P, the returned thread end E _G and the fiber ring R,. In addition, this length section has the wild windings W and is therefore particularly thick. The entire length section of the thread corresponding to the circumference U of the spinning rotor 110 is still excessively thick, but not quite as thick as the length section A _L with the wild windings W. Depending on the duration of the downtime of the delivery device 13 before piecing while the opening roller 141 continues to run, the length section A or A mentioned (see FIG. 5 a)) adjoins the length section corresponding to the circumference U (see FIG. 5 a)) has a thickness deviating from the normal thread, this length section or A _{c may be} stronger or weaker than the normal thread.

In the case of a thread take-off G _{b L} , G _{b 20} according to FIG. 6, the fiber feed F _b only reaches its full production value (100%) at the time T ₂ , ie later than at the time T ₅ at which the thread take-off G _b has already reached its full production value (100%). The resulting thick point D _: increases from the time T ₃ to the time T ₄ , since during this time the thread take-off G _{b is} still less than the fiber feed F _b as a percentage, and then decreases again because the fiber feed F _b is then smaller than the thread take-off G _b . This thick point O ₁ is then followed by a thin point D ₂ in the length section A _c (see FIG. 5 a)) from the moment at which the fiber ring R _{F has been} fully integrated into the piecer P, which leads to the Time T _{5 reaches} its thinnest point and ends at time T ₂ .

The thick point in the piecing P formed by the windings W (fiber bridge B _{F 2} ) can be reduced by a shorter pre-feeding, ie by a thinner fiber ring R _F. Then the thick point O _λ still remains. If the thread take-off G _{b is} increased, on the one hand there is a very high take-off tension and with it the risk of thread breaks. In addition, the length section A _L formed by the overlap of the thread end E _G and newly added fibers becomes too thin, which in turn leads to thread breaks. In order to avoid this thick spot D, and to nevertheless have sufficient fibers for the attachment, according to FIG. 6, after the fiber ring R _{F has} essentially reached the desired strength, the fiber flow which is still increasing is temporarily for kept constant for a short time or even abruptly reduced in order to achieve a synchronous run-up of fiber feed F _b and thread take-off G _b as quickly as possible. This reduction in the fiber flow should be carried out as suddenly as possible, that is to say almost immediately, that is to say as quickly as possible, since the effect is all the more intense the faster the reduction in the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 and thus the reduction of the fiber flow is. If, on the other hand, the change in the penetration depth is slow, it has practically no effect on the fiber flow. The thread thickness cannot then be influenced, but in this way the fiber beard 21 can be brought into a desired starting or production position without changing the thread thickness.

For example, a further increase in the fiber flow is prevented at time T ₆ and is only permitted again from time T ₇ .

In the exemplary embodiment shown, thread take-off G _b and fiber feed F _b have reached the same percentage who * in terms of their production values from time T ₈ and from then on start up synchronously (see fiber feed F _b , and thread take-off). train G _{b 3} ) until they simultaneously reach their respective production values at time T ₉ . The synchronous run-up of fiber feed F _bx and thread take-off G _b _ is achieved by adapting the thread take-off G _{b 3 to} the fiber feed adapted to the start of the fiber feed F _b _ reduced by the reduction in the penetration depth of the fiber beard 21 onto the fiber collecting surface 17 is controlled.

As already described above, it is not sufficient to adapt the thread draw alone to reducing the depth of penetration of the fiber beard, but it is also necessary to take the condition of the fiber beard 21 into account. This is done in the simplest manner in that the fiber beard 21 immediately before its return movement from its position with increased depth of penetration into the clothing 143 of the opening roller into its position of reduced depth of penetration, at least approximately in a state of equilibrium between those per unit of time combed fibers 22 on the one hand and with the fibers 22 fed with the sliver on the other hand. If the amount of combed fiber per unit of time increases due to the impaired state of the fiber beard 21 at the moment of the fiber beard withdrawal, then depending on the magnitude of this increase rate, the effect of the position change depending on the position change speed can be canceled or at least reduced.

To determine the state of the fiber beard at the time of piecing, the time from the response of the thread

T Guard 16 serve until the start of the piecing process, since the degree of fiber beard impairment depends on this time, ie the downtime of the feed device 13 with the opening roller 141 continuing to run.

If necessary, however, the condition of the fiber beard 21 can also be determined by direct optical or pneumatic measurement.

In order to reduce the take-off acceleration in the first phase of the thread draw-off, since the fibers collected in the spinning rotor 110 cannot yet lead to sufficient strength in the attachment P, and to counteract the thick point caused by the fiber bridge B _F _ 6 that the thread take-off (acceleration phase G _{b 0} ) after the start (time T _{:) of} the fiber feed F _b onto the fiber collecting surface 17 (FIG. 11) / but before the usual start of take-off (time T ₃ ), begins with very little acceleration (time T-. ₀ ) and after a short duration changes into the acceleration phase G _b _ (time T. -_). The triangle DR ₄ which results between the times T _: and T _{: 0} is very small, which means that only a very thin fiber ring has formed before the start of the thread take-off. Due to the slow initial acceleration of the thread take-off, however, enough fibers 22 can still lay on the thread end E _G located in the take-off, so that a secure attachment is guaranteed. If, in addition, the increase in the fiber feed F _b between the times T ₆ and T is temporarily kept constant or even reduced, such a piecing device P is quite inconspicuous if the thread end E _G is tapered before the return delivery and an im essentially wedge-shaped shape is obtained (FIG. 12).

5 b) to 5 d), the thick point formed by the thread breaks B _F _ (see FIG. 11) is compensated. For this purpose, the leading end of the fiber sliver 2, which forms a fiber beard 21, is first fed to the opening roller 141 for piecing at a penetration depth that is greater than the penetration depth after piecing. The transition from the larger to the lower penetration depth takes place in coordination with the release of the sliver, where the piecing process in turn is coordinated with the change in penetration depth.

5 b), 5 c), the fiber feed F _{b is} reduced to the fiber collecting surface of the spinning rotor 110 essentially at that point in time at which the fibers 22, which later form the first length section A, are temporarily only reduced Dimensions are left on the fiber collecting surface (see Fig. 5 b) and 5 c). 5 b) indicates the circumference of the opening roller 141 with the dash-dotted line and the working group of the clothing 143 of the opening roller with the dotted line. With "max" is the maximum and with "min" the minimum depth of engagement of the fiber beard 21 in the

REPLACEMENT LEAF Set 143 of the opening roller 141 shown. As shown, the depth of penetration of the fiber beard 21 before piecing is particularly high (max), while it is reduced at the desired time during piecing (min). During this change, ie reducing the depth of penetration of the fiber bar 21 into the clothing 143 of the opening roller 141, the fiber flow F _{b is} briefly reduced to the fiber collecting surface in order to return immediately to its normal value (see FIG. 5 c)) .

As a comparison of FIG. 5 a) (piecing P _b ) with FIG. 5 d) shows, the thick point otherwise unavoidable in the length range A _{L has} disappeared. This is due to the fact that the fiber supply to the fiber collecting surface 17 begins at the point in time at which the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 is reduced.

In the exemplary embodiment shown in FIG. 5 d), only the thick point in the adjoining area of the thread section corresponding to the circumference U of the spinning rotor 110 is still contained in the newly spun thread.

By temporally controlling the change in penetration depth, one or the other thick point can either be fully or at least largely compensated for. If several penetration depth change devices 4 are provided, as will be described below with the aid of FIG. 1, then several thick spots can also be eliminated. After the desired effect and the method to be carried out for this have been described above, a penetration depth change device 4 for the fiber beard 21 for carrying out the described method will now be described with the aid of FIG. 1. This penetration depth change device 4 is formed by the vacuum source 32, the vacuum line 18 and the switching device designed as a switching valve 181 in the vacuum line 18, the switching valve 181 being connected to the control device 30 in terms of control.

During the preparation work for piecing, after cleaning the spinning element, e.g. of the spinning rotor 110, the spinning vacuum is switched off by closing the switching device 115. The suction air flow generated by the vacuum source 32 is brought into effect by opening the switching device 181, which can happen shortly before or at the same time or also shortly after the spinning vacuum is switched off. Due to the negative pressure acting in the open-end spinning device 11 in the thread take-off tube 112, the thread released by the spool 122 in a known manner is introduced into the thread take-off tube 112 in a conventional manner, but without the fiber collecting surface of the spinning rotor 110 or any other design Touch spinning element.

Opening the switching device 181 prevents the spinning element from being cleaned after being reinserted.

ERSÄΓZB VTT switch the feed device 13 still more fibers 22 can get onto the fiber collecting surface. After opening the switching device 181, the feed device 13 is switched on again. The fiber stream is now sucked out of the housing 140 through the suction air opening 180. Since the spinning vacuum is switched off on the housing 113 of the open-end spinning device 11, the suction air flow brought into effect at the suction air opening 180 is sufficient to convey the fibers 22 into the suction air opening 117 via the mouth 117 of the fiber feed channel 111. In this way it is ensured that the fibers 22, which were adversely affected by the continuing opening roller 141 in the time from the shutdown phase of the delivery device 13, do not get into the spinning rotor 110.

By throwing off the ejector spindle 33, the thread previously prepared for spinning is returned to the fiber collecting surface due to the negative pressure (negative pressure source 32) applied to the housing 140 and also acting in the spinning rotor 110 via the spinning rotor 111. Timed thereupon, the switching device 181 is closed and the switching device 115 is opened, so that the stronger vacuum source 32 becomes ineffective by switching it off, while the weaker vacuum source 116, which is present on the fiber collecting surface 17 and causes the spinning vacuum, is switched on again by switching on Effect is brought. As a result of this switching over of the negative pressure, the fibers 22 now suddenly reach the spinning rotor 110. End E _G and fibers 22, the fibers 22 deposited on the fiber collecting surface 17 are incorporated into the thread end E _G. The thread is then withdrawn from the spinning rotor 110 with the constant inclusion of the continuously fed fibers 22 and wound up on the spool 122.

The negative pressure effect which affects the fiber beard 21 is kept until the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 is maintained at a level which ensures the increased depth of penetration, which is significantly higher than is required for spinning so that a significant change in the penetration depth of the fiber beard 21 and thus the fiber flow is achieved. For this purpose, the vacuum ratios of the air flows that are generated by the vacuum sources 32 and 116 are selected such that the vacuum source 32 generates a significantly higher vacuum than the vacuum source 116.

While the vacuum source 32 acts, the fiber beard 21 is drawn deep into the clothing 143 of the opening roller 141 due to the high vacuum. Thereafter, the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 remains constant for the duration of the vacuum source 32. When switching from the high negative pressure of the negative pressure source 32 to the lower negative pressure of the negative pressure source 116, something is lifted out of the garnish 143 of the opening roller 141 due to the sudden reduction in the negative pressure effect, whereby the thread

REPLACEMENT LEAF serstrom for the duration of the swiveling movement of the fiber beard

21 is temporarily reduced somewhat from the deeper into the less deep penetration depth. As a result, fewer fibers temporarily arrive during the formation of the piecer

22 into the spinning rotor 110, as a result of which the inevitable thickening of the thread 20 region of the piecing P is significantly reduced. Depending on the intensity and speed of the change in the negative pressure, by changing the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141, thread thickness reductions of at least 10%, u. U can even reach up to 30%, so that yarn thickness fluctuations of over 10%, possibly even up to 30%, can be compensated for.

Due to the continuous feed of the sliver 2, the depth of penetration of the sliver 21 slowly increases again to the normal spinning value, so that the normal operating fiber flow * to the fiber collecting surface is then achieved again. The time period until the operating fiber supply is reached again depends on the feed speed of the fiber sliver 2.

The reduced depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 is now maintained for production, so that no further changes to the vacuum acting in the housing 140 of the opening roller 141 are now necessary. In principle, it is possible to change the depth of penetration of the fiber sliver 21 into the clothing 143 of the opening roller 141 in the sense of an enlargement or in the sense of a reduction in the penetration depth. The previously described penetration depth changing device 4, which is formed by the vacuum source 32 with the associated vacuum line 18 and the switching valve 181, is a penetration depth increasing device since it works in the sense of increasing the penetration depth. As will be described later, it is also possible to design a (modified) penetration depth changing device 4 as a penetration depth reduction device.

The switching off of the negative pressure on the line 18 or the mouth 180 is controlled in time so that the sudden slight lifting of the fiber beard 21 from the clothing of the opening roller 141 coincides with the attachment. Thickness compensation is achieved in this way.

With the rapid increase in the fiber flow from the vacuum line 18 into the spinning rotor 110, the thread 20 according to FIG. 8 is suddenly exposed to the clamping effect of the driven draw-off roller pair 15 after the first phase G _a j of the draw-off G _{a has ended} , through which the In the second piecing phase, thread 20 is brought suddenly (between times T ₆ and T ₅ ) to the take-off speed (100%) that is effective during production. Any thread excess that arises as a result is formed by forming a thread reserve or compensated by higher acceleration of the coil 122.

For example, in a manner known per se, the thread 20 arrives in the clamping line of the pair of draw-off rollers 15, the draw-off roller 151 (pressure roller) of which is initially lifted off the driven draw-off roller 150 and for the insertion of the thread draw-off G _a at the desired point in time (T ₆ ) is placed again on the driven take-off roller 150 and thus causes the abrupt take-off acceleration, while the take-off takes place in the first phase G _a j with the aid of the coil 122.

As FIG. 8 shows, the phase G _a _ • of the thread take-off G _a can already begin before the deflection of the fiber flow has ended and the fiber feed F _{a has started} on the fiber collecting surface (time T, ₀ ), at which time due to the reduced vacuum effective after the switchover, the penetration depth of the fiber beard 21 into the clothing 143 of the opening roller 141 is suddenly reduced. Thus, the yarn withdrawal _Ga before the Eindring¬ is deep reduction begins with the phase _Ga _ already.

Before the thread end E _G leaves the fiber collecting surface 17, however, fibers 22 get there, and the fiber feed F now rises very rapidly. As a result of this rapid increase in the fiber feed F, (between the times T _: and T ₂ ) it is achieved that the piecer P is still in its length section A _L has a sufficiently large fiber mass, which also ensures the required strength. As shown in FIG. 9, the piecing P is not only very short, but even ends before the fibers deposited on the entire circumference U of the fiber collecting surface have been spun into the new thread.

Here, too, there is a small thick point D ₃ in the piecing P, which essentially depends on the shape of the returned thread end E _G , but cannot be completely avoided in the usual way even with an optimally prepared thread end E _G. However, if the penetration depth changing device 4 is controlled accordingly, so that in connection with these switching operations the fiber beard is lifted somewhat out of the clothing 143, the thick point D _{3 can also be} compensated here (see fiber feed F _{a :)} . A corresponding dimensioning of the negative pressures in the negative pressure lines 114 and 18 is necessary for this.

The depth of penetration of the fiber beard 21 into the clothing 143 can also be reduced in another way. A further possibility for this is shown in FIGS. 1 to 3.

The increase in the negative pressure for the change in the penetration depth of the fiber beard 21 into the clothing 143 of the opening roller 141 can in principle also take place on the fiber collecting surface 17. However, since the suction acting on the thread end E _G provided for the piecing back delivery is also

TT effect is increased, which leads to an impairment of the thread end E _G , it is better, as described, to bring the increased negative pressure into effect at such a point which is after the feed point of the fiber beard 21 to the opening roller (feed device 13), on which the fibers 22 have not yet reached the fiber collecting surface 17. This then also enables a solution as described above and according to which the fibers 22 are led away into the clothing 143 of the opening roller 141 until the depth of penetration of the fiber beard 21 without having previously reached the fiber collecting surface 17, and essentially are only fed to the fiber collecting surface 17 when the penetration depth is reduced. Depending on the desired effect, smaller time shifts are possible.

The change in the negative pressure acting in the housing 140 for the opening roller 141 need not be made by switching between two negative pressure sources (32 and 116). Much more can u. It may also be provided that the vacuum source 116 is not controlled and always remains effective, while the vacuum source 32 is temporarily brought into effect.

The penetration depth changing device 4 is thus formed together by the two negative pressure sources 116 and 32 as essential components, the increased penetration depth of the fiber beard 21 into the clothing 143 of the opening roller. ze 141 is achieved by the simultaneous action of both negative pressure sources 32 and 116. It can be provided that in order to remove the fibers 22 already released by the delivery device 13 for spinning, only the vacuum source 32 is switched on, and then in order to achieve the increased depth of fiber beard penetration, the vacuum source 116 is additionally switched on, so that Both vacuum sources 116 and 32 work overlapping until the vacuum source 32 is rendered ineffective until the depth of penetration is reduced.

The increased vacuum can in principle be controlled by switching the vacuum source 32 on and off. However, this is not excessively favorable, since the negative pressure in the negative pressure line 18 builds up relatively slowly. For this reason, it is better, as shown in FIG. 1, if there is a switching valve 181 in the vacuum line 18, which separates the vacuum source 32 already operating from the suction air opening 180 or connects it to the latter.

The switching on of the air flow desired for the change in the depth of the fiber beard can thus in principle be done by switching on the vacuum source 32, but this is best done by opening the switching valve 181. The air flow is then switched off in an analogous manner by closing the switching valve 181 .

According to the first variant shown in FIGS. 1 and 2, the

TT In addition or as an alternative to the embodiment described above, as in the exemplary embodiment described above, an underpressure after the fiber beard feed area to the opening roller 141 is brought into effect which exceeds the underpressure effective after the piecing. According to the example now to be described, however, this takes place in that the penetration depth change device 4 is provided in or on the feed trough 131 and a compressed air channel 40 opening into the feed trough 131 and thus in the length region of the fiber beard 21 the outlet 41 connected to the compressed air duct 40 and opposite the set of the opening roller 141 and radially opposite it, and an overpressure source (compressed air source 42) acting on the compressed air duct 40 in a controlled manner. The compressed air source 42 is - as indicated by a dashed line 34 is controlled by the control device 30 so that either a compressed air flow in the compressed air channel 40 is generated or this is switched off.

When the air flow is switched on, an air jet emerges from the outlet opening 41, which allows the fiber beard 21 to penetrate deeper into the clothing 143 of the opening roller 141 (FIG. 3). If the air jet is switched off, the fiber beard 21 lifts again somewhat out of the clothing 143 (see FIG. 2), and correspondingly fewer fibers 22 are supplied to the fiber collecting surface 17 of the spinning rotor 110 during the lifting movement. The switching off of the compressed air source 42, which is initially switched on, is controlled by the control device 30 (FIG. 1) in such a way that it is switched off immediately before the piecing is formed in such a way that after the slight fluff of the fiber beard 21 comes out of the clothing 143, the fibers supplied briefly in a smaller number reach the fiber collecting surface 17 just at the moment when the piecer P is formed. This counteracts the formation of a thick spot in the area of the piecing P.

If, for example, more fibers 22 are required for a short time to compensate for a thin point D ₂ (FIG. 7) following the thick point, the compressed air source 42 can also be suddenly switched on again at a suitable time. In order to subsequently obtain normal operation, the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141 after piecing has to be brought back up to the initial value at the time when the penetration depth changing device 4 working with compressed air is still was not turned on. This reduced penetration depth is then maintained for production. In order to achieve this, the air flow supplied by the compressed air source 42 is steadily reduced to zero so slowly that practically no change in the fiber feed quantity occurs during this time.

As described, if the penetration depth change device 4 has a constructional and functional reasons, the effect thereof can be traced back to the starting basis For the transition to production conditions - either a thin spot must be mitigated by selecting an appropriate return speed (see FIG. 5 d)) or, if no thin spot can be compensated for, the return of the fiber beard 21 to the production position must be so slow that none noticeable fiber flow influence is achieved and thus a constant thread thickness is maintained.

It is of course also possible in an analogous manner to design the penetration depth changing device 4 as a suction air device instead of the compressed air source 42 and to connect it to a vacuum source, e.g. to the vacuum source 32, in which case a switching device (not shown) for controlling the vacuum can then be arranged between the outlet opening 41 - which then naturally forms a suction air opening. In this case, the penetration depth change device 4 forms a penetration depth reduction device.

In order to keep fiber loss as low as possible, it is advantageous if the suction air opening 41 is covered by a sieve.

The penetration depth changing device 4 shown in FIGS. 1 to 3, but to a vacuum source instead of to a compressed air source 42, can also be modified in a particularly simple manner to determine the state of the fiber beard 21 become. For this purpose, it is only necessary to assign a manometer (not shown) to the (outlet) opening 41 forming a suction air opening. To determine the state of the fiber beard 21, while the feed device 13 is not released, pressure is then applied to the opening 41 and the pressure drop occurring is measured with the help of the manometer, which is caused by air being sucked through the opening 41 laying fiber beard 21 enters the opening 41. The measure of the pressure drop is directly related to the density of the fiber beard 21 and thus enables a statement about the state of the fiber beard 21.

Before piecing, the fiber beard 21 is exposed to the usual spinning vacuum, so that it is exposed to the action of the opening roller 141 with the same penetration depth as during normal production. In order to lift the fiber beard 21 somewhat out of the clothing 143 of the opening roller 141 when the delivery device -13 is switched on again after it has been released for piecing, the penetration depth change device 4 is activated by the vacuum source assigned to this device (e.g. vacuum source 32) by switching on or by releasing by means of a switching device, not shown (analogous to switching valve 181). In coordination with this, the piecing process is carried out by returning the thread end E _G to the fiber collecting surface 17 and pulling off the thread end E _{G again} .

REPLACEMENT LEAF Since the penetration depth change device 4 should not be effective during the normal spinning process, that is to say under production conditions, for reasons of economy, the air flow generating device 4 is deactivated again after the piecing process. If a thin point is to be compensated for in this way (see thin point D ₂ in FIG. 7), this switch-off process takes place relatively quickly, so that the fiber beard movement caused thereby leads to a noticeable influence on the fiber flow.

If there is no such thin point to be compensated, the penetration depth change device 4 is slowly deactivated by gradually controlling the decrease in the vacuum so that the fiber flow is not appreciably affected. In this way, after the rapid reduction in the penetration depth of the fiber beard 21 into the clothing 143 of the opening roller 141, which is brought about for influencing the thread thickness, when the fiber supply has reached its full value (100%), the penetration depth of the Fiber beard 21 changed so slowly that the amount of fiber combed out by the opening roller 141 per unit of time practically does not change.

As soon as the penetration depth change device 4 is completely ineffective, the maintenance device 3, if it controls the penetration depth change device 4, can leave the open-end spinning device 11 on which the piecing process has been carried out. The depth of penetration of the fiber beard 21 is controlled according to the exemplary embodiments described so far by exposing the fiber beard 21 to a controllable air flow. However, this is not the only way to change the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141. Another possibility of reducing the depth of penetration of the fiber beard 21 into the clothing of the opening roller 141 is to make the entire feeding device 13 or only a part thereof, for example the feeding trough 131, adjustable, for example by slightly removing the opening roller about the axis 132 141 can be tilted away. An adjusting device 133 connected to the feed device 13 or the feed trough 131 can pivot the feed device 13 or the feed trough 131 from the opening roller 11 so far away based on a suitable control signal (see line 35) from the opening roller 11 that the penetration depth of the fiber beard 21 is just reduced by the desired amount.

In coordination with the release of the sliver 2, the control device 30 emits a suitable signal to the adjusting device 133, whereupon the feed device 13 suddenly swings slightly away from the opening roller 141 and the depth of penetration of the fiber bar 21 into the clothing 143 of the opening roller 141 is correspondingly reduced becomes. During the sudden swiveling process, a smaller amount of fiber is delivered to the spinning rotor 110. In time with the release of the sliver 2 and the The feed device 13 or the feed trough 131 is fed to and withdrawn from the thread of the fiber collecting surface 17, thereby counteracting the formation of a thick spot and completely compensating, or at least reducing, it. Then, if desired, an opposite effect can then be achieved by suddenly swiveling the fiber beard 21 into the clothing 143 of the opening roller 141.

According to FIG. 4, a guide surface 43, for example in the form of a sheet metal plate, can also be provided at the exit of the feed trough 131 relative to the sliver 2 and can be more or less delivered to the feed roller 130 by an adjusting device 430. The adjustment of the guide surface 43, which is articulated on the feed trough 131 by means of a pivot axis 431, can be done e.g. B. by means of an armature 433 hinged to the guide surface 43 of an electromagnetic device 432.

Before the piecing process, the guide surface 43, which is part of the penetration depth change device 4, is displaced by the adjusting device 430 into its upper end position in relation to FIG. 4, where the penetration depth of the fiber bar 21 into the clothing 143 is greatest. For the formation of the piecing device, a control signal 30 is then sent to the control device 430, whereupon the control device 43 uses the electromagnetic device 432 to guide the guide surface 43 into a normal distance a little further away from the feed roller 130. drive position switches. During this switchover, the fiber beard 21 reduces its depth of penetration into the clothing 143, and the desired reduction in the fiber flow occurs precisely at the moment in which the piecing is formed. Then, depending on the speed of the switch in the opposite direction, the fiber flow can be increased briefly and thus noticeably or imperceptibly slowly.

Another pneumatically operating penetration depth change device 4 is explained with the aid of FIG. 10. In this embodiment, the opening roller 141 is designed as a perforated hollow body with openings 144 in the peripheral wall. With the interior of the opening roller 141 is a suction channel 44 is connected, which is connected to a not presented darge vacuum source, the effect of - (not shown), in particular through the intermediary of a switching valve - ^'switched on and off. An insert 440 is arranged in a stationary manner inside the opening roller 141, which has a suction channel 441 oriented from the opening of the suction channel 44 located in the opening roller 141 towards the inside of the opening roller 141 in the length region of the fiber beard 21.

In order to be able to pull the fiber beard 21 deeper into the clothing 143 of the opening roller 141, a negative pressure is brought into effect in the suction channels 44 and 441. If the fiber beard 21 is to return to the starting position, then

ATZBLATT this suction air flow switched off.

In an analogous manner, an overpressure source can also be provided instead of a suction air source, so that the fiber beard 21 can be brought from the normal position into the position of lower penetration depth by overpressure.

In order to increase the penetration depth changes, alternatively both in the device according to FIG. 10 and in the device shown in FIGS. 2 and 3, suction and compressed air can alternatively be used, while in a neutral mean penetration depth the Fiber beard 21 neither compressed air nor suction air is used.

As the above description shows, the method and device can be modified in a variety of ways within the scope of the present invention, in particular by exchanging features by equivalents or by other combinations of the individual features. For example, it is also possible to combine the effect of several devices to form a common penetration depth changing device 4. 1 shows a vacuum source 32 with a vacuum line 18, which is provided in addition to the compressed air source 42 and the outlet opening 41. It goes without saying that the devices forming the common penetration depth changing device 4 must be synchronized in their function via the control device 30. However, it is not only possible to combine pneumatically operating devices to form a common penetration depth changing device 4 with a synchronized function. The device shown in FIG. 4 can thus be combined with the vacuum line 18 or also with the outlet opening to which compressed air can be applied, as shown in FIGS. 2 and 3.

Furthermore, it is also possible in such a kombi¬-defined penetration depth changing device 4, the Ansprech¬ points in time and to provide response times of deviating from each other by the control device 30 to both the be¬ worked example, at a piecing P in FIG. 7 by the B _F _ To counteract the thick point and the thick point D, on the one hand and on the other hand the thin point D ₂ . As clearly shown in FIG. 7, different responses and, if appropriate, also times are required for addressing the penetration changing device 4.

Instead of two vacuum sources 116, 32 (FIG. 1), it is also possible to use a single vacuum source, which can then be connected to the vacuum line 114 or 18 via a separate switching valve 115 or 181. Since differently high pressures are required in the two vacuum lines 114 and 18, a line valve must also be provided in the line 114, the function of which is to generate the required vacuum drop.

REPLACEMENTB As a rule, when controlling the fiber flow by changing the depth of penetration of the fiber beard 21 into the clothing 143 of the opening roller 141, the state of equilibrium between the fiber sliver supply to the opening roller 141 and the fiber flow feed to the fiber collecting surface need not be taken into account due to the very rapid required Change in the penetration depth of the fiber beard 21. In individual cases, however, it may be advantageous to wait before changing the penetration depth of the fiber beard 21 in the clothing 143 of the opening roller 141 until such a balance has been reached, for. B. by fiber stream switching of a full fiber stream or by a starter and another brief shutdown of the delivery device 13 immediately before the change in the penetration depth of the fiber beard 21 into the clothing 143 of the opening roller 141.

According to the exemplary embodiments described, a movable maintenance device 3 is provided, on which the piecing device and its control device 30 are located. Iεt with simpler machines, e.g. B. Teß machines or devices, no such maintenance device 3 provided, the elements described on the open-end spinning machine 1 or the spinning station 10, possibly two adjacent spinning stations 10 together, are directly assigned.

Claims

Patent claims

1. A method for piecing a thread in an open-end spinning device having a fiber collecting surface, in which a sliver of fiber is fed to the clothing of a dissolving roller and dissolved by it into fibers and in this form is fed to the fiber collecting surface, where the fibers end of a returned thread which is then continuously drawn off, characterized in that the leading end of the sliver forming a fiber beard is fed with a penetration depth which is greater than the penetration depth later after piecing for the piecing of the opening roller , while piecing is carried out in a conventional manner in coordination with a reduction in the penetration depth.

2. The method according to claim 1, characterized in that the fiber feed to the fiber collecting surface begins at the beginning of the reduction in the depth of penetration of the fiber beard in the clothing of the opening roller.

3. The method according to claim 2, characterized in that the thread take-off is controlled in adaptation to the reduced start-up of the fiber feed onto the fiber collecting surface by the reduction of the penetration depth of the fiber bar.

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4. The method according to one or more of claims 1 to

3, characterized in that the thread draw-off begins before the depth of penetration of the fiber beard into the clothing of the opening roller is reduced.

5. The method according to one or more of claims 1 to

4, characterized in that the state of the fiber beard is determined at the beginning of the piecing and the start and / or the acceleration of the thread draw-off is adapted to the state of the fiber beard in such a way that the thread draw-off begins later with a more combed fiber beard and / or starts with a lower acceleration than with less combed fiber beard.

6. The method according to one or more of claims 1 to

5, characterized in that the fiber beard is at least approximately in an equilibrium state between fibers combed per unit of time on the one hand and fibers fed with the fiber band on the other hand immediately before its return movement from the increased penetration depth.

7. Process according to one or more of claims 1 to

6, characterized in that the difference between the increased penetration depth and the reduced penetration depth after the piecing is selected such that a thread thickness reduction of at least 10% takes place immediately after the abrupt return movement of the fiber beard into the reduced penetration depth .

8. The method according to claim 7, characterized in that the difference is chosen so that the Fadendickenredu¬ reduction is between 10 and 30%.

9. The method according to one or more of claims 1 to

8, characterized in that the reduction of the penetration depth is carried out abruptly.

10. The method according to one or more of claims 1 to

9, characterized in that the reduced depth of penetration of the fiber beard in the clothing of the opening roller is maintained for production.

11. The method according to one or more of claims 1 to 9, characterized in that the depth of penetration of the fiber beard into the clothing after piecing is increased again to the initial value and this depth of penetration is then maintained for production.

12. The method according to claim 11, characterized in that after the fiber feed has again at least substantially assumed the value corresponding to the production after the reduction in the penetration depth, the increase in the penetration depth is carried out so slowly that during the increase in penetration depth the amount of fibers combed out by the opening roller per unit of time practically does not change.

13. The method according to one or more of claims 1 to 12, characterized in that the fiber beard for Controlling its depth of penetration into the clothing of the opening roller is exposed to a controllable air flow.

14. The method according to claim 13, characterized in that to increase the penetration depth of the fiber beard into the clothing of the opening roller according to the area in which the fiber type of the opening roller is fed, a vacuum is brought into effect which is effective after piecing Negative pressure exceeds.

15. The method according to claim 14, characterized in that the increased pressure acting on the area where the fiber beard is fed to the opening roller is brought into effect at a point at which the fibers have not yet er¬ the fiber collecting surface have enough.

16. The method according to claim 15, characterized in that the fibers are removed to reduce the depth of penetration of the fiber beard without first having reached the fiber collecting surface and being fed to the fiber collecting surface only when the penetration depth is reduced.

17. The method according to one or more of claims 14 to 16, characterized in that the reduction of the negative pressure takes place by switching off an air flow exceeding the spinning negative pressure and switching on a weaker air flow acting on the collecting surface. - .T3-

18. The method according to one or more of claims 14 to

17, characterized in that the negative pressure effect until the point in time of reducing the penetration depth is maintained at a value which ensures the increased penetration depth and is significantly higher than the negative pressure after piecing.

19. The method according to one or more of claims 13 to

18, characterized in that the increase in the penetration depth is brought about by switching on and the reduction in the penetration depth of the fiber beard is brought about by switching off an air flow again.

20. The method according to one or more of claims 1 to 12, characterized in that the change in the depth of penetration of the fiber beard is carried out by adjusting a feed device feeding the sliver of the opening roller or a part thereof.

21. The method according to one or more of claims 1 to 12, characterized in that the change in the depth of penetration of the fiber beard is carried out by adjusting a feeder and the opening roller provided between the one fiber strip of the opening roller and the mechanical guide surface provided for the opening roller.

22. Open-end spinning device with a dissolving roller arranged in a housing and a clothing, a feed device connected upstream of the dissolving roller for feeding a fiber band to the dissolving roller, ~ bv - a fiber collecting surface and a vacuum source assigned to the fiber collecting surface, a fiber feed channel leading from the opening roller to the fiber collecting surface for supplying fibers from the end of the fiber band forming a fiber beard and engaging with the clothing of the opening roller to the fiber collecting surface, one the piecing device assigned or deliverable to the open-end spinning device and with a control device controlling the piecing process, for carrying out the method according to one or more of claims 1 to 21, characterized by a depth of penetration of the fiber beard (21) into the clothing (143) the opening roller (141) controlling the penetration depth changing device {4), which is connected in terms of control to the control device (30).

23. The device according to claim 22, characterized in that the penetration depth changing device (4) at least in one of the two changing devices is abruptly adjustable.

24. The apparatus of claim 22 or 23, characterized gekenn¬ characterized in that the penetration depth changing device (4) is formed as a penetration depth increasing device, which can be brought suddenly ineffective.

25. The device according to one or more of claims 22 to 24, characterized in that the penetration depth changing device (4) with the control device (30) in terms of control in connection, in the length- rich of the fiber beard (21) in the housing (140) of the opening roller (141) has an overpressure source.

26. The device according to one or more of claims 22 to 24, characterized in that the penetration depth change device (4) with the control device (30) in terms of control in connection, in the housing (140) of the opening roller (141) can be brought into effect ¬ terdruckquelle (32) has.

27. The apparatus according to claim 26, characterized in that the vacuum collecting surface (17) assigned to the fiber collecting surface (17) and the vacuum source (32) connected in a control manner with the control device (30) together form the penetration depth changing device (4) and can be brought into effect overlapping.

28. The apparatus according to claim 26, characterized in that the penetration depth changing device (4) in the fiber transport path between feeder device (13) and fiber collecting surface (17) can be brought into effect.

29. The device according to claim 28, characterized in that the vacuum source (32) with a in the peripheral wall (142) of the housing (140) of the opening roller (141) provided suction air opening (180) is in connection or can be brought. - έ_ -

30. The device according to claim 29, characterized in that the suction air opening (41) is arranged in the longitudinal region of the fiber beard (21).

31. The device according to claim 30, characterized in that the suction air opening (41) is covered by a sieve.

32. Device according to one or more of claims 29 to 31, characterized in that a fiber collecting container (182) is provided between the suction air opening (180, 41) and the vacuum source (32).

33. Device according to one or more of claims 29 to 32, ^' characterized in that the suction air opening (180, 41) can optionally be brought into connection with the vacuum source (32) and with a pressure source.

34. Apparatus according to claim 25 or 26, characterized gekenn¬ characterized in that the positive or negative pressure source is connected to the interior of the opening roller (141) which has a perforated outer surface.

35. Apparatus according to claim 25 or 26, characterized gekenn¬ characterized in that the negative pressure or positive pressure source (42) opens into a part of the feed device (13) forming feed trough (131) and substantially radially against the set (143) Opening roller (141) is directed.

36. Device according to one or more of claims 22 to 35, characterized in that the control device (30) is arranged on a maintenance device (3) which can be moved along a plurality of similar open-end spinning devices.

37. Device according to one or more of claims 22 to 24, characterized in that the penetration depth changing device (4) has an adjusting device (133) for the feed device (13) or a part (131) thereof.

38. Device according to one or more of claims 22 to 24, characterized in that the penetration depth changing device (4) has an adjustable guide surface (43) arranged in the region of the fiber bar (21).

39. Device according to one or more of claims 22 to 38, characterized by a device connected to the piecing device in terms of control in order to determine the state of the fiber beard (21) at the beginning of the piecing process, which is connected to the control device (30).

40. Device according to claim 39, characterized in that the device for determining the state of the fiber beard (21) is connected via the control device (30) to the penetration depth changing device (4).

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