SPINNING BOX FOR AN OPEN-END ROTOR SPINNING DEVICE

Description

[0001] The present invention relates to a spinning box for an open-end rotor spinning device, in particular for a semi-automatic rotor spinning device, according to the preamble features of claim 1.

[0002] Such a spinning box is known, for example, from document EP 3 153 612 A1. Another spinning box is known from document EP 2 963 164 A1. Spinning boxes are used in the usual way to protect the components required for the production of a spun thread from the environment. Thus, known spinning boxes house a separating unit by means of which a supplied fiber bundle is separated and parallelized into individual fibers. The separated fibers are guided via a fiber guide channel leading from the separating unit to a spinning rotor located in the spinning box onto its fiber slide wall. The rotation of the spinning rotor causes the individually supplied fibers to slide from the fiber slide wall into a radial fiber groove of the spinning rotor, in which the separated fibers adhere to an open end of a spun thread end laid in the fiber groove.Simultaneously, the yarn is drawn from the spinning box via a yarn take-up channel that communicates with the spinning rotor cup, thus continuously forming the yarn into a retractable strand as it is attached. If spinning is interrupted, for example by a yarn break or cut, a re-spinning process is required to resume. In this process, a yarn end coming from the take-up bobbin must be fed into the yarn take-up channel and onto the spinning rotor. For optimal re-spinning results, the yarn end must be separated and prepared by unraveling or twisting it so that the individual fibers can attach more reliably to the open yarn end. This preparation is typically carried out using a service unit or within the spinning box by the spinning rotor itself, as described, for example, in document EP 3 276 057 A1.The first option is advantageous for automatic open-end spinning machines, but unsuitable for semi-automatic open-end spinning machines that lack a service unit. The latter solution is suitable for these machines. However, this requires the spinning rotor to be driven in a specific manner, which can shorten the service life of the spinning rotor drive for pure yarn production.

[0003] The present invention is intended to provide an alternative method for preparing a spun thread end for a spinning process, in particular protected from the ambient air, and furthermore particularly suitable for semi-automatic open-end spinning machines.

[0004] A spinning box is proposed, featuring a fiber tape inlet for feeding a fiber tape to a disassembly unit, which can be arranged in a disassembly unit receptacle within the spinning box, and a yarn exit opening through which a spun yarn produced from the fed fiber tape can be discharged from the spinning box. The spinning box incorporates a yarn end preparation unit for preparing the yarn end, with the yarn end preparation unit positioned opposite the yarn exit opening for the mutual transfer of a spun yarn. This allows for yarn end preparation within the spinning box, protected from the ambient air, and in particular, independent of a service unit and without compromising the service life of a spinning rotor drive. Such a spinning box is especially suitable for semi-automatic open-end spinning machines, but can also be used with fully automatic open-end spinning machines.

[0005] According to the present invention, the spinning box has a yarn insertion recess that communicates with the yarn exit opening and can be functionally connected to the yarn end preparation unit. A spinning yarn can be transferred from the yarn exit opening into this recess, which extends in a defined direction away from the yarn exit opening. The yarn insertion recess thus increases the design freedom of the spinning box. The yarn end preparation unit can be arranged within the spinning box at a selected location as required, taking into account the available space.

[0006] Preferably, the spinning box comprises a first housing side and a second housing side, which adjoins the first housing side at an angle of less than 180°, wherein the yarn exit opening is formed in the first housing side and wherein the yarn insertion recess extends from the yarn exit opening into the second housing side and is, in particular, at least partially slot-shaped. This allows the yarn to be transferred from the yarn exit opening into the yarn insertion recess without additional contact of the yarn with a spinning box edge, which could adversely affect the hairiness of the yarn.Preferably, the spinning box has a third housing side which adjoins the second housing side at an angle of less than 180°, wherein the yarn insertion recess extends from the yarn exit opening into the third housing side and is, in particular, at least partially slot-shaped. This allows for a more reliable, contactless transfer of the spinning yarn into the yarn insertion recess for a yarn preparation process using the yarn end preparation unit.

[0007] Preferably, the first, second, and, in particular, third sides of the housing are formed by an attachment that can be detachably fastened to the spinning box. This attachment can be achieved using conventional clamping, snap-fit, screw connections, or similar positive-locking and / or force-locking connection types that allow for non-destructive, repeatable removal of the attachment. Such an attachment facilitates the reliable transfer of the spinning yarn from the yarn exit opening to the yarn insertion recess and provides access to the yarn end preparation unit, for example, to troubleshoot malfunctions or replace worn parts.

[0008] According to a further preferred embodiment, the attachment in the direction of the spinning thread forms at least one final component of the spinning box or, more preferably, the final component of the spinning box, which further preferably forms a component that is raised or protrudes from the other housing sides of the spinning box.

[0009] Preferably, the housing sides of the attachment mounted on the spinning box are flush with the outer surface surfaces of the spinning box adjacent to these housing sides. Furthermore, preferably, a front surface surface of the spinning box adjacent to the fiber tape inlet is formed at least largely or completely from at least one housing side of the attachment.

[0010] Preferably, the yarn end preparation unit includes a yarn cutting unit, for example, a yarn cutting unit, which is arranged in the spinning box opposite the yarn insertion recess for cutting a yarn received in the insertion recess. The yarn cutting unit can thus be arranged away from the normal yarn path, reliably preventing disruption of the spinning process in the event of a defect in the yarn cutting unit.

[0011] Preferably, a yarn guide ramp is arranged within the spinning box, which is positioned relative to the yarn insertion recess in such a way that a spinning thread inserted into the insertion recess can be guided in a defined manner via the yarn guide ramp. This reduces, or ideally eliminates, the risk of the spinning thread becoming entangled during insertion into the insertion recess.

[0012] The yarn guide ramp is particularly preferably arranged between the yarn take-off channel outlet and the yarn cutting unit, wherein the yarn guide ramp projects beyond the yarn take-off channel outlet along the take-off direction of the yarn, more preferably with a ramp surface extending transversely to and away from the yarn take-off channel outlet, in order to reliably guide the yarn into or to a yarn cutting point of the cutting unit during the insertion process. For example, the yarn cutting unit can be designed, in particular by the yarn cutting unit, to include two blade elements that are movable relative to each other, wherein the blade elements form a cutting opening for cutting the yarn.The thread guide ramp is further preferably designed and arranged corresponding to a cutting edge of one of the blade elements, whereby the spinning thread is reliably guided into the cutting opening, preferably to the cutting base of the cutting opening, during insertion, in order to enable reliable cutting of the spinning thread.

[0013] According to a preferred embodiment of the present invention, a thread sensor is arranged in the spinning box, associated with the thread insertion recess, to detect a spinning thread inserted into the thread insertion recess. More preferably, the thread cutting unit can be controlled by the thread sensor or an intermediate control unit, based on a detection signal from the thread sensor, to cut the spinning thread inserted into the thread insertion recess. This allows for automated initialization of the spinning thread cutting.

[0014] According to a preferred embodiment of the present invention, the spinning box has a cleaning housing which includes a discharge channel extending along the dissolving unit receptacle, with an inlet opening open to an outer surface surrounding the spinning box, an outlet opening that can be coupled to a dirt channel of the spinning machine, and a receiving opening arranged between the inlet and outlet openings, which is open to the dissolving unit receptacle for the purpose of removing dirt particles from the dissolving unit receptacle. The cleaning housing also has a feed opening leading into the discharge channel, away from the receiving opening, for conveying dirt particles and fiber residues. The feed opening allows the cleaning housing, and in particular the discharge channel, to be used for removing dirt particles from areas of the spinning box other than the dissolving unit receptacle.Typically, as previously disclosed in document EP 2 963 164 A1, the cleaning housing is designed to discharge dirt particles and fiber remnants released during the singulation of the fed fiber bundle into a dirt channel of the open-end spinning machine. For this purpose, the discharge channel is pressurized with negative pressure, whereby the inlet opening, which communicates with the ambient air, ensures that there is no continuous increase in negative pressure within the dissolving unit housing. When negative pressure is applied, this results in a continuous airflow in the discharge channel, which is directed from the inlet opening towards the outlet opening. This allows dirt particles and fiber remnants to be carried away from the dissolving unit housing via the intermediate receiving opening. This carry-along effect is also utilized by the arrangement of a feed opening in the discharge channel, away from the receiving opening.In particular, the feed opening is connected via a connecting channel to a discharge opening of the yarn end preparation unit. This allows the separated yarn end section, as well as dirt particles and fiber remnants, to be reliably removed during yarn end preparation, such as cutting and / or unwinding. The yarn end preparation unit includes a yarn end unwinding unit for unwinding a yarn end introduced into the yarn exit opening. This unwinding unit is formed by a yarn take-off channel, which can be operatively connected to a spinning rotor and has a yarn take-off channel outlet located in the spinning box opposite the yarn exit opening. The discharge opening is positioned upstream of the yarn end unwinding unit in the yarn take-off channel in the yarn pull-off direction.

[0015] Preferably, the feed opening is arranged between the inlet opening and the receiving opening, particularly near the inlet opening, and more preferably directly downstream of the inlet opening. This allows for easier access to the feed opening, for example for cleaning purposes.

[0016] Preferably, the feed opening is formed by an insert which is arranged in the discharge channel, and is particularly replaceable. This further simplifies the cleaning of the feed opening. Furthermore, the feed opening can be adapted to different fiber materials that can be processed by the open-end spinning machine or in the spinning box.

[0017] According to a preferred embodiment, the spinning box, as described above, is a component of a spinning unit of an open-end spinning machine, in particular a semi-automatic rotor spinning machine. According to a preferred embodiment, the spinning unit comprises a spinning rotor, preferably individually driveable, whose rotor cup rotates at high speed in a vacuum-operated rotor housing during spinning. The rotor housing can be closed by a cover element formed by the spinning box. A dissolving unit, in particular a dissolving roller, is arranged in the dissolving unit receptacle of the spinning box, to which a fiber web can be fed via the fiber tape inlet.The dissolving roller is designed and positioned to break down the fiber mass into individual fibers, whereby dirt particles and / or fiber remnants detached from the fiber mass are conveyed via the cleaning housing into a dirt channel of the spinning machine. A fiber guide channel located in the spinning box is operatively connected to the dissolving roller, through which the dissolved fibers can be fed to the spinning rotor cup. Opposite the spinning rotor cup is a yarn take-off channel inlet, with the yarn take-off channel extending from the inlet to a yarn take-off channel outlet within the spinning box, opposite the yarn exit opening.

[0018] The spinning device according to this preferred embodiment enables the preparation of a spun thread end during a spinning process to be carried out completely within the spinning box, protected from the ambient air.

[0019] According to a further aspect of the present invention, a method for spinning a yarn in an open-end spinning machine, in particular a semi-automatic rotor spinning machine, is proposed, wherein the open-end spinning machine has a spinning device as described above. In the method, a yarn passing through the yarn exit opening is transferred in one step from the yarn exit opening into the yarn insertion recess. The transfer can be carried out manually by an operator or automatically, for example by means of a yarn clamping unit which is designed to be movable outside the spinning box relative to the yarn path. The yarn clamping unit can be assigned to a service unit operating the spinning device, to a spinning station comprising the spinning device, or to the spinning device itself.After the yarn is transferred to the yarn insertion recess, the yarn cutting unit is initialized to cut the inserted yarn. Initialization can preferably be carried out by means of a yarn sensor monitoring the yarn insertion recess, as described above by way of example. Alternatively, initialization can be triggered by an operator action, such as activating a yarn cutting signal by operating a control device. The initialization of the yarn cutting unit can be triggered directly by the control device or via a control unit. The cut yarn segment is preferably disposed of within the spinning box via the cleaning housing, as described above. The cut yarn end is presented to the yarn exit opening for insertion into the spinning box, in particular into the yarn take-up channel.Preferably, a suction flow is present at the yarn take-up channel outlet, by which the yarn end is drawn into the yarn take-up channel. The suction flow can preferably be generated by the compressed air supply and / or by the negative pressure applied at the discharge opening. The yarn end introduced into the yarn take-up channel is then prepared by the yarn end preparation unit. For this purpose, the yarn end is preferably unwound or twisted in the yarn take-up channel with a predominant compressed air supply. After the unwound process, the unwound yarn end is fed to the spinning rotor, in particular the spinning rotor cup, for continuation of the spinning process.

[0020] Exemplary embodiments of the invention are explained below with reference to the drawings. The drawings show: Fig. 1 shows a schematic representation of an embodiment of a spinning box; Fig. 2 shows a schematic representation of the one inFigure 1 Figure 3 shows a spinning box with the top removed, Figure 3 shows a schematic perspective view of a top according to one embodiment, Figure 4 shows a schematic perspective view of a section of a spinning box with a top according to another embodiment, and Figure 5 shows a schematic perspective view of the top in Fig. 4 The section of the spinning box shown is without the attachment.

[0021] Figure 1 and 2Figure 1 shows a spinning box 1 according to an exemplary embodiment. The spinning box 1 has a fiber tape inlet, which, in the illustrated embodiment, is preceded by a fiber tape feeder comprising a pre-compressor 10 and a driven feed roller 12 downstream in the fiber tape transport direction. The fiber tape is pre-compressed and transported via the fiber tape inlet into the spinning box 1 to a dissolving roller (not shown), which serves as a dissolving unit. For the discharge of a spun yarn 2 produced by a spinning rotor (not shown) covered by the spinning box 1, the spinning box 1 has a yarn exit opening 4. Adjoining the yarn exit opening 4 is a yarn insertion recess 8, into which the spun yarn 2 can be seamlessly transferred from the yarn exit opening 4. The yarn insertion recess 8 extends in a slot-like manner from the yarn exit opening 4 in a direction leading away from it.The yarn exit opening 4 and the yarn insertion recess 8 are formed in an attachment 6, which is detachably or non-destructively attached to the spinning box 1 via a snap-fit ​​connection. The attachment 6 forms a first housing side 6a and a second housing side 6b for the spinning box 1, wherein the yarn exit opening 4 is formed on the first housing side 6a and the yarn insertion recess 8 extends into the second housing side 6b. The first housing side 6a and the second housing side 6b are adjacent to each other, forming an angle of less than 180°.

[0022] Figure 3 shows a further embodiment of the attachment 6, which differs from the one in Figure 1The illustrated attachment 6 differs only by a third housing side 6c, in which the thread insertion recess 8 extends and which is formed adjacent to the second housing side 6b including an angle of less than 180°.

[0023] The spinning box 1 is designed to accommodate a yarn end preparation unit, which is configured for preparing the spinning yarn 2. According to this embodiment, the yarn end preparation unit is arranged within the spinning box 1 opposite the yarn exit opening 4 and the yarn insertion recess 8. The yarn preparation unit comprises a yarn cutting unit 20, which is configured as a yarn cutting unit with a first blade element 21 and a second blade element 22 that is movable relative to the first blade element 21 for cutting the spinning yarn 2. The second blade element 22 is coupled to a retractable piston for this purpose.The thread cutting unit 20, with its cutting opening formed by the first blade element 21 and second blade element 22, is arranged parallel to a thread take-off channel 30 adjacent to a thread take-off channel outlet 32 ​​opposite the thread insertion recess 8, wherein the thread take-off channel outlet 32 ​​is opposite the thread exit opening 4.

[0024] The yarn end preparation unit further comprises a yarn end dissolution unit, which is positioned upstream of the yarn take-off channel outlet in the yarn take-off channel 30 in the direction of yarn 2 take-off. The yarn end dissolution unit has a pneumatic connection 34 through which compressed air can be introduced into the yarn take-off channel 30 in a known manner, against the direction of take-off, to generate a vortex airflow in the yarn take-off channel 30 in order to dissolution a yarn end held in the yarn take-off channel 30 in the area of ​​the yarn end preparation unit.

[0025] The spinning box 1 has a cleaning housing 40, which, in the usual manner, features a discharge channel 41 extending along the dissolving unit receptacle, with an inlet opening 42 open to an outer surface surrounding the spinning box 1, an outlet opening that can be connected to a dirt channel of the spinning machine, and a receiving opening arranged between the inlet opening 42 and the outlet opening, which is open to receive the dissolving unit for the purpose of removing dirt particles from the dissolving unit receptacle. Contrary to the usual design, the cleaning housing 40 includes, apart from the receiving opening, a feed opening leading into the discharge channel 41 for introducing dirt particles. The feed opening is formed in an insert 50, which is replaceably arranged in the base of an inlet area of ​​the discharge channel 40 near the inlet opening 42.The feed opening is coupled to a discharge opening by means of a connecting hose or channel, which is located upstream in the thread discharge channel 30 of the thread end disassembly unit in the discharge direction.

[0026] Figures 4 and 5Figure 1 shows a schematic perspective view of a section of a spinning box 1 with an attachment 50 according to a further embodiment. According to this further embodiment, the spinning box 1 has a ramp-like upper surface, with the attachment 50 extending across the front surface of the spinning box 1 adjacent to the upper surface, encompassing the pre-compressor 10 and the feed roller 12. According to this further embodiment, the attachment 50 extends across the front surface of the spinning box 1 along the take-off direction of the yarn 1 from the upper surface to a position adjacent to the fiber feed, and in a direction orthogonal to the take-off direction and leading away from the fiber feed, largely across the front surface; in this embodiment, it extends across the entire front surface of the spinning box 1.

[0027] The attachment 50 according to these further embodiments is therefore larger in its dimensions than the one in Figures 1 to 3 The attachment 50 shown is designed so that the attachment 50 can be more reliably and releasably fixed to the spinning box 1, and after removing the attachment 50 from the spinning box 1, a larger access area into the spinning box 1 is also provided, which enables easier and more reliable operation of the components covered by the attachment 50, such as the thread cutting unit 20, inside the spinning box 1.

[0028] The attachment 50 is detachably fixed to the spinning box 1 by means of locking devices. Suitable locking devices include, for example, complementary locking latches and locking recesses 16 on the spinning box 1 and the attachment 50.

[0029] Furthermore, the attachment 50 is inserted in a recess 14 of the spinning box 1, wherein at least the outer surface sides of the spinning box 1 are flush with the housing sides 6a, 6b, 6c of the attachment 50, i.e., at least on the outside, they merge seamlessly into one another.

[0030] Within the spinning box 1, a yarn guide ramp 60 is arranged between the yarn take-up channel 30 and the yarn cutting unit 20. The ramp has a ramp surface 62 extending transversely to and away from the yarn take-up channel outlet 32, guiding the yarn 1, which is inserted into the yarn insertion recess 8, towards the bottom of the cutting opening of the yarn cutting unit 20. The yarn guide ramp 60 projects beyond the yarn take-up channel outlet 32 ​​in the direction of yarn 2 take-up. According to this embodiment, the yarn guide ramp 60 is designed and arranged correspondingly to the cutting edge of the first blade element 21, ensuring that the yarn 2 is reliably guided into the cutting base of the cutting opening.

[0031] The spinning box 1 is a component of a spinning unit of an open-end rotor spinning machine, wherein the spinning unit comprises a precisely driven spinning rotor whose rotor cup rotates at high speed in a vacuum-operated rotor housing during spinning. The rotor housing can be closed by a cover element formed by the spinning box 1. A dissolving roller is arranged in the dissolving unit receptacle of the spinning box 1, to which the fiber bundle can be fed via the fiber tape inlet. The dissolving roller is arranged and configured to break down the fiber bundle into individual fibers, whereby dirt particles and / or fiber remnants detached from the fiber bundle are discharged via the cleaning housing into a dirt channel of the spinning machine. A fiber guide channel arranged in the spinning box 1 is operatively connected to the dissolving roller, through which the broken-down fibers can be fed to the rotor cup.Opposite the spinning rotor cup is a yarn extraction channel inlet, wherein the yarn extraction channel 30 extends from the yarn extraction channel inlet to the yarn extraction channel outlet 32 ​​opposite the yarn exit opening 4 within the spinning box 2.

[0032] During the spinning process, the generated yarn 2 is drawn from the spinning box 1 through the yarn exit opening 4 in a direction leading away from the spinning box 1 and fed to a winding device to form a bobbin. A yarn sensor is arranged between the spinning box 1 and the winding device to monitor the characteristics of the moving yarn 2. As soon as the yarn sensor detects a defined deviation, a controlled interruption of the spinning process occurs, accompanied by a controlled yarn cut. According to one embodiment, a movable yarn clamping unit can be provided to clamp the exiting yarn 2 and guide it from the yarn exit opening 4 into the yarn insertion recess 8. The yarn clamping unit can be assigned to a service unit operating the spinning device, to a spinning station encompassing the spinning device, or to the spinning device itself.The yarn insertion recess 8 is equipped with a further yarn sensor for detecting the yarn 2 in the yarn insertion recess 8, wherein, according to this preferred embodiment, the further yarn sensor is arranged within the spinning box 2. As soon as the further yarn sensor detects the presence of the yarn 2 in the yarn insertion recess and transmits this information to a control unit, for example, a workstation computer of the spinning machine, the control unit initiates the cutting of the yarn 2 via the yarn cutting unit 20. The cut yarn end section is drawn into the discharge opening by the applied negative pressure and disposed of via the cleaning housing 40. The yarn clamping unit presents the cut yarn end to the yarn exit opening 4, so that the yarn end can be drawn into the yarn discharge channel 30.A suction flow is present at the yarn discharge channel outlet 32, allowing the yarn end to be drawn into the yarn discharge channel 30. This suction flow can preferably be generated by the compressed air supply via the compressed air connection 34 and / or by the negative pressure applied at the discharge opening. Within the yarn discharge channel 30, a swirling air flow is generated in the area of ​​the yarn end preparation unit by the supplied compressed air to break up the yarn end. After breaking up, the yarn end is fed to the spinning rotor in the usual manner for spinning to continue, while maintaining the compressed air supply and releasing the clamp, for example, by releasing the yarn clamping unit.

[0033] According to a further embodiment, in the event of a yarn break, where a yarn end runs onto the take-up bobbin in the usual manner, the yarn end can be retrieved via a return unit and fed into the yarn take-up channel 30 through the yarn exit opening 4. The return unit can be assigned to the service unit or the spinning station with the spinning device. Manually or automatically, the yarn 2 can be transferred from the yarn exit opening 4 into the yarn insertion recess 8, whereby a yarn cut is made in the manner described above. The severed yarn section is disposed of as described above. The cut yarn end is fed manually or automatically through the yarn exit opening 4 into the yarn take-up channel and, as also described above, unwound in order to then be fed to the spinning rotor to continue spinning. Reference symbol list

[0034] 1 Spinning box 2 Spinning thread 4 Thread exit opening 6 Attachment 6 First housing side 6 Second housing side 6 Third housing side 8 Thread insertion recess 10 Pre-compressor 12 Feed roller 14 Recess 16 Rake recess 20 Thread cutting unit 21 First blade element 22 Second blade element 30 Thread take-off channel 32 Thread take-off channel outlet 34 Compressed air connection 40 Cleaning housing 41 Discharge channel 42 Inlet opening 50 Insert 60 Thread guide ramp 62 Ramp surface

Claims

1. Spin box (1) for an open-end spinning machine, having a sliver entrance for feeding a sliver to an opening unit, which can be arranged in an opening unit receptacle of the spin box (1), a thread outlet opening (4), via which a spinning thread (2) produced from the fed sliver can be led out of the spin box (1), and a thread-end preparation unit for preparing a spinning-thread end, whereby the thread-end preparation unit is accommodated by the spinning box (1), whereby the thread-end preparation unit is arranged facing the thread outlet opening (4) for the mutual transfer of the spinning thread (2), characterized in that the spin box (1) has a thread insertion recess (8), which communicates with the thread outlet opening (4) and can be operatively connected to the thread-end preparation unit, and into which the spinning thread (2) can be transferred from the thread outlet opening (4), the thread insertion recess (8) extending in a defined way from the thread outlet opening (4) in a direction leading away therefrom.

2. Spin box (1) according to claim 1, characterized in that the spin box (1) has a first housing side (6a) and a second housing side (6b), which adjoins the first housing side (6a) such that an angle of less than 180° is included, the thread outlet opening (4) being formed in the first housing side (6a), and the thread insertion recess (8) extending from the thread outlet opening (4) into the second housing side (6b) and being at least partly slot-shaped.

3. Spin box (1) according to claim 2, characterized in that the first housing side (6a) and the second housing side (6b) are formed by an attachment (6), which can be removably fastened to the spin box (1).

4. Spin box (1) according to any one of the preceding claims 2 and 3, characterized in that the thread-end preparation unit has a thread severing unit (20), which is arranged, in the spin box (1), facing the thread insertion recess (8) in order to sever a spinning thread (2) received in the thread insertion recess (8).

5. Spin box (1) according to any one of the preceding claims 2 to 4, characterized by a thread sensor, which is arranged in the spin box (1) such that the thread sensor is associated with the thread insertion recess (8), in order to sense the spinning thread (2) received in the thread insertion recess (8).

6. Spin box (1) according to claims 4 and 5, characterized in that the thread severing unit (20) can be triggered, by the thread sensor or by an interposed control unit, on the basis of a sensing signal of the thread sensor, to sever the spinning thread (2) inserted in the thread insertion recess (8).

7. Spin box (1) according to any one of the preceding claims 2 to 6, characterized by a thread guide ramp (60), which, within the spin box (1), is associated with the thread insertion recess (8) such that a spinning thread (2) inserted into the thread insertion recess (8) can be guided in a defined way by means of the thread guide ramp (60).

8. Spinning device for an open-end spinning machine, characterized by a spin box according to any one of the preceding claims.

9. Method for piecing in an open-end spinning machine, characterized by a spinning device according to claim 8, the method comprising a step of severing the spinning thread (2) exiting from the spin box (1), a following step of delivering the cut spinning-thread end to the thread outlet opening (4) for insertion into the spin box (1), a subsequent step of preparing the inserted spinning-thread end by means of the thread-end preparation unit, and a subsequent step of feeding the prepared spinning-thread end to a spinning rotor of the spinning device.