Spinning machine and method for spinning a yarn having a core thread
By improving the design of the drafting device and yarn guide of the spinning machine, the fibers in the fiber belt are ensured to be parallel and separated, and the core yarn is accurately positioned inside the yarn. This solves the problem of unstable core yarn positioning in the existing technology and realizes the production of beautiful core-spun yarn.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SAVIO MACCHINE TESSILI SPA
- Filing Date
- 2025-12-22
- Publication Date
- 2026-06-23
AI Technical Summary
In the prior art, when manufacturing core-spun yarns, especially yarns with elastic cores, air-jet spinning machines have difficulty stably positioning the core yarn at the center of the fiber, resulting in poor yarn appearance. Existing solutions such as twisting guides cannot effectively solve this problem.
A spinning machine is employed, comprising a drafting device, an air-jet spinning unit, and a core yarn feeding assembly. The drafting device causes the fibers to converge in parallel, and a yarn guide ensures that the fibers in the fiber belt are parallel and separated. The core yarn is inserted into the fiber belt and enters the air-jet spinning chamber. The yarn guide is designed to keep the fibers parallel and tangle-free before they enter the air-jet spinning chamber. The feeding assembly controls the feeding speed and tension of the core yarn to ensure accurate positioning of the core yarn inside the yarn.
It achieves precise positioning of elastic or non-elastic core yarns inside the yarn, resulting in a beautiful yarn appearance and complete fiber coverage of the core yarn. This solves the problem of exposed core yarns in existing technologies and is suitable for the production of yarns with both elastic and non-elastic core yarns.
Smart Images
Figure CN122257162A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a spinning machine for spinning yarns with elastic or non-elastic cores, and a method for spinning yarns with elastic or non-elastic cores. Background Technology
[0002] The purpose of this invention is to overcome the known limitations currently existing in air-jet spinning machines used for manufacturing core-spun yarns (especially yarns with elastic cores, but not limited thereto), and to improve the quality of the yarns produced.
[0003] It should be noted that "elastic core yarn" refers to an elastic fiber, such as elastic polyurethane, elastomeric polyurethane, elastic synthetic fibers (such as elastic fibers), Lycra, Dorlast, and Spandex. Elastic core yarn refers to a core yarn with an elongation at break greater than 100%.
[0004] "Non-elastic core yarn" refers to yarn that does not have significant elastic elongation at break characteristics; typically, non-elastic core yarn refers to core yarn with an elongation at break of less than 100%.
[0005] Air-jet spinning technology applied to (elastic or inelastic) core-spun yarns still faces some unresolved technical limitations. The main issue involves guiding and positioning the (elastic or inelastic) core or monofilament at the center of the fiber so that the fiber completely covers the core or monofilament. In fact, if the core is missing or only partially covered, the resulting yarn is considered defective in conventional applications due to its unsatisfactory appearance.
[0006] Figure 1a An embodiment of a core-spun yarn with appearance defects is shown, wherein the core yarn is at least partially visible from the outside, while Figure 1b It shows that the core wire is accurately positioned and completely encased inside the yarn, making it invisible from the outside.
[0007] Existing technologies include solutions (such as those according to US 5647197 A) that incorporate twisting guides to allow fibers to converge tightly at the exit point, thereby improving spinning performance. However, such solutions do not guarantee that the core yarn position is stably maintained, often resulting in at least partial exposure of the core yarn, as... Figure 1a As shown in the diagram.
[0008] Therefore, it is necessary to address the shortcomings and limitations associated with existing technological solutions. Summary of the Invention
[0009] This invention provides a spinning machine for spinning yarns having a core yarn that is elastic or inelastic. The spinning machine includes: - a drafting device comprising at least two pairs of drafting rollers that are columnar and rotate about mutually parallel drafting axes. The drafting device is configured such that fibers in at least one fiber strip fed into the drafting device along a feed path become parallel to each other between the at least two pairs of drafting rollers, and the at least one fiber strip converges across a centerline plane in the feed path; - an air-jet spinning unit disposed downstream of the drafting device and including an air-jet spinning chamber configured to form yarn by winding or twisting fibers that have become parallel through the drafting device; A core yarn feeding assembly is arranged upstream of the last pair of drafting rollers in at least two pairs of drafting rollers and configured to introduce the core yarn into the interior of at least one fiber strip, and then allow the at least one fiber strip to enter the interior of the air-jet spinning chamber and be wound around the core yarn. A yarn guide is arranged at the entrance of the air-jet spinning unit. The yarn guide is designed to receive the fibers in the at least one fiber strip and keep the fibers parallel and separated from each other until the fibers enter the air-jet spinning chamber.
[0010] This invention provides a method for spinning yarn with an elastic or non-elastic core, comprising the following steps: - preparing a spinning machine for spinning yarn with a core, - preparing an elastic core as the core, - feeding the elastic core to a core feeding assembly by means of a feed roller according to the control of the core feed speed, controlling the rotation of the feed roller so that the feed roller feeds the core at a speed of 1 / 6 to 1 / 3 of the spinning speed, thereby applying a preload to the core, wherein the spinning speed is the forward speed of the fiber belt inside the air-jet spinning chamber.
[0011] The present invention provides a method for spinning yarn with an elastic or non-elastic core, comprising the following steps: - preparing the aforementioned spinning machine for spinning yarn with a core, - preparing a non-elastic core as the core, - feeding the non-elastic core to a core feeding assembly, thereby feeding the core with a controlled tension. Attached Figure Description
[0012] Other features and advantages of the invention will become more clearly understood from the following description of preferred and non-limiting embodiments thereof, in conjunction with the accompanying drawings:
[0013] Figure 1a A perspective view of a yarn with defects according to the prior art is shown;
[0014] Figure 1b A view of yarn formed by a spinning machine according to the present invention is shown;
[0015] Figure 2 A side view of a spinning machine according to a possible embodiment of the present invention is shown;
[0016] Figure 3 It shows Figure 2 Enlarged details of a section of the spinning machine;
[0017] Figure 4a and Figure 4b Perspective views of a fiber strip associated with a feed assembly and a yarn guide, according to an embodiment of the present invention, are shown from different perspectives.
[0018] Figure 5 It shows Figure 4a and Figure 4b Side view of the feed assembly and yarn guide;
[0019] Figure 6 It shows Figure 4a and Figure 4b Top view of the feed assembly and yarn guide;
[0020] Figure 7 It shows Figure 6 Enlarged details of part VII;
[0021] Figure 8 It shows Figure 6 Enlarged details of part VIII;
[0022] Figure 9 A perspective view of a yarn guide according to an embodiment of the present invention is shown;
[0023] Figures 10 to 11 Cross-sectional views of yarn guide assemblies according to different embodiments of the present invention are shown;
[0024] Figures 12 to 14 Cross-sectional views of core wire feeding assemblies according to different embodiments of the present invention are shown;
[0025] Figures 15 to 17 The yarn clamping and cutting steps performed by the core wire feeding assembly according to an embodiment of the present invention are shown in sequence.
[0026] Figure 18 A cross-sectional view of the connection part of the yarn guide in the air-jet spinning unit is shown.
[0027] The components or parts of components common to the embodiments described below will be indicated using the same reference numerals. Detailed Implementation
[0028] Referring to the foregoing figures, reference numeral 4 generally indicates a general schematic diagram of a spinning machine according to the invention, specifically indicating an air-jet spinning machine of the "air jet spinning" type.
[0029] It should be noted that the terms "thread" or "single thread" or "continuous thread" refer to a single filament or continuous filament (e.g., in the case of silk, man-made fibers, or synthetic fibers), while the term "yarn" refers to a group of parallel filaments joined together by twisting. These two terms will be used indiscriminately below, and it should be understood that the invention is not limited to either type of use.
[0030] The spinning machine 4 includes an air-jet spinning unit 8 of a known type, which is configured to form yarn 10 starting from at least one fiber strip (preferably two fiber strips 12, 16) that has undergone pretreatment of the drafted fibers. Specifically, the air-jet spinning unit 8 includes an air-jet spinning chamber 9, which is configured to wind the input fibers and output the formed yarn 10.
[0031] At the end of the drafting step, the core filament 20 (i.e., elastic or non-elastic filament) needs to be introduced into the fiber.
[0032] Therefore, after the drafting step, the fibers are parallel to each other and thus ready to be wound or twisted around the core 20, whether the core is made of elastic filaments or non-elastic filaments.
[0033] Therefore, the spinning machine 4 for air-jet spinning includes a drafting device 24, which includes at least one pair of drafting rollers 28 that are columnar and rotate about mutually parallel drafting axes XX. Generally, the drafting device 24 includes multiple pairs of drafting rollers 28 that rotate about mutually parallel drafting axes XX. Figure 2 , Figure 4a , Figure 4b , Figure 5 , Figure 6 Four pairs of stretching rollers 28 are shown.
[0034] As mentioned, the drafting device 24 is configured to feed at least one parallel fiber strip (e.g., two fiber strips 12, 16) along a feed path P into the drafting device 24, in which the fiber strips 12, 16 converge from opposite sides relative to the centerline plane MM. In the case of only one fiber strip 12, 16, the fiber strip converges across the centerline plane MM.
[0035] As shown in the figure, the spinning machine 4 includes an air-jet spinning unit 8 arranged downstream of the drafting device 24, which is configured to form yarn 10 by winding or twisting parallel fibers passing through the drafting device 24.
[0036] The spinning machine 4 also includes a core thread feed assembly 36 arranged upstream of the air-jet spinning unit 8, the core thread feed assembly being configured to introduce the core thread 20 between the fibers in at least one fiber belt 12, 16 before the fibers in at least one fiber belt 12, 16 enter the air-jet spinning unit 8 and are wound around the core thread 20.
[0037] Specifically, the core wire feed assembly 36 includes an outlet nozzle 94, which is configured and / or tilted to insert the core wire 20 between fibers in at least one fiber belt 12, 16 at the centerline plane MM along a tangential direction TT, which is tangential to the outer sidewall 44 of one of the at least one pair of drafting rollers 28 and intersects the feed path P, with the outlet nozzle intersecting upstream of the air-jet spinning unit 8.
[0038] Downstream of the outlet nozzle 94 and at the inlet of the air-jet spinning unit 8, a yarn guide 40 is arranged. This yarn guide is designed to receive fibers from at least one fiber strip 12, 16 and keep these fiber strips parallel and separated from each other until they enter the air-jet spinning chamber 9. Furthermore, the yarn guide 40 is configured to insert the core yarn 20 between the fibers in at least one fiber strip 12, 16 at the centerline plane MM.
[0039] In other words, the yarn guide 40 is configured to guide the fibers in at least one parallel and therefore non-entangled fiber band 12, 16 until they enter the air-jet spinning chamber 9, where the yarn 10 is formed.
[0040] When using two fiber strips 12 and 16, these two fiber strips are fed into the yarn guide 40 from opposite sides of the centerline plane MM in a parallel and separate manner until they enter the air-jet spinning chamber 9, where the core yarn 20 is inserted between the fiber strips 12 and 16 at the centerline plane MM. Therefore, in the same case, the fibers remain parallel to each other and parallel to the core yarn 20 without tangling until they enter the air-jet spinning unit 8, where they are then formed into yarn 10.
[0041] According to one embodiment, the yarn guide 40 includes a pair of sliding planes 48 that are inclined toward each other to form a vertex 52 and are configured to slidably guide two fiber bands 12, 16, thereby keeping the two fiber streams parallel and separate.
[0042] Preferably, vertex 52 is located on the centerline plane MM.
[0043] According to the embodiment, the sliding plane 48 is inclined from the inlet end 42 directly facing the draft roller 28 along the axial extension direction AA of the yarn guide 40 to the outlet end 43 directly facing the airflow spinning chamber 9 in a manner of separation followed by convergence.
[0044] According to the embodiment, due to the inclined design of convergence and separation, at the inlet end 42 where the fiber enters the yarn guide 40, the vertex 52 defines an inlet vertex angle 60 between the sliding planes 48, which is between 180° and 215°, preferably between 195° and 205°.
[0045] Furthermore, at the exit end 43 where the fiber leaves the yarn guide 40, the vertex 52 defines an exit vertex angle 62 between the sliding planes 48, which is between 120° and 150°, preferably between 130° and 140°.
[0046] According to an embodiment, the spinning machine 4 includes a pre-tensioning device for the elastic core yarn 20, which includes a feeding system that controls the insertion speed of the elastic core yarn when it is inserted into the core yarn feeding assembly 36.
[0047] According to one embodiment, the feeding system includes a feed roller 72 that can operate at a variable speed.
[0048] Preferably, if the core yarn 20 is an elastic core yarn, the feed roller 72 is operated to feed the core yarn 20 at a speed of 1 / 3 to 1 / 6 times the spinning speed (i.e., the forward speed of the fiber belts 12, 16 inside the air-jet spinning unit 8), thereby applying a preload effect to the core yarn 20.
[0049] According to an embodiment, the spinning machine 4 includes a yarn clearer 80 configured to analyze the yarns 10 leaving the airflow spinning unit 8.
[0050] According to an embodiment, the core wire feeding assembly 36 further includes:
[0051] At least one clamp 84 is configured to selectively hold the core wire 20.
[0052] At least one wire cutter 88 is configured to selectively cut the previously clamped core wire 20.
[0053] At least one Venturi effect nozzle 92 is configured to selectively generate a suction flow for drawing the core wire 20 from the inlet nozzle 93 to the outlet nozzle 94.
[0054] According to the embodiment, the core yarn feed assembly 36 is operatively connected to the yarn clearer 80 and / or operatively associated with a release signal triggered at the end of spinning. Therefore, the core yarn feed assembly 36 can operate based on defects detected by the yarn clearer 80, and / or based on the end of the spinning process or the depletion of the fiber strip.
[0055] According to the embodiment, the clamp 84 and the wire cutter 88 are operatively connected to each other, such that the clamp 84 is first operated to clamp the core wire 20, and then the wire cutter 88 is operated to cut the yarn 10.
[0056] Specifically, the steps of clamping the yarn 10 are performed in sequence as follows: Figure 12 , Figure 13 , Figure 14 As shown in the diagram. The next cutting step is... Figure 15 , Figure 16 , Figure 17 As shown in the image.
[0057] According to the embodiment, the clamp 84 and the wire cutter 88 are anchored to the same operating piston.
[0058] According to the embodiment, the nozzle 92 and the gripper 84 are operatively connected to each other so that they are activated simultaneously each time the spinning process is restarted.
[0059] In other words, during the restart step, it is necessary to simultaneously activate the clamp 84 and generate (Venturi) airflow through the Venturi effect nozzle 92 to ensure accurate positioning of the core wire 20 in the outlet nozzle 94.
[0060] This synchronization is crucial, especially to compensate for the high elastic tension of the core yarn 20: if the yarn 10 is cut before the start nozzle 92 and thus the venturi airflow is initiated, there is a risk that the yarn 10 will retract; conversely, if the start nozzle 92 is initiated after the yarn is cut by the cutter 88 and thus the venturi airflow is formed, the yarn 10 may become tangled, especially if the core yarn 20 is of the elastic type.
[0061] Therefore, it is necessary to start the airflow for a period of time so that the core wire 20 is first introduced into the outlet nozzle 94, and then the core wire is centered between the fiber belts 12 and 16.
[0062] According to possible variations, the core wire feed assembly 36 includes two Venturi nozzles 92 configured to selectively generate a suction flow for drawing the core wire 20. In particular, the first Venturi nozzle 92' is arranged upstream of the holder 84, and the second Venturi nozzle 92'' is arranged downstream of the holder 84.
[0063] Specifically, suction occurs only at the horizontal height of the two Venturi effect nozzles 92' and 92'', and the Venturi effect is activated to cause the core wire 20 to slide into the outlet nozzle 94.
[0064] The two Venturi effect nozzles 92' and 92'' can be activated simultaneously, or sequentially by activating the second Venturi effect nozzle 92'' first and then the first Venturi effect nozzle 92''. This is to prevent the core wire 20 from piling up between the inlet nozzle 93 and the outlet nozzle 94.
[0065] As can be understood from the description, the present invention enables the overcoming of the disadvantages of the aforementioned prior art.
[0066] In particular, compared to existing solutions, the present invention enables precise and repeatable positioning of the core yarn inside the yarn, whether the yarn is elastic or not.
[0067] The core yarn is positioned tangentially within the aforementioned parallel and separated fiber bands, achieving optimal positioning within the yarn and allowing the fiber bands to symmetrically and completely wrap around and cover the core yarn. Therefore, the resulting yarn will be aesthetically pleasing, as the core yarn will be completely concealed within the surrounding fibers.
[0068] The specific geometry of the yarn guide allows the fiber strips to remain parallel and separate until they enter the air-flow spinning chamber.
[0069] Advantageously, the present invention enables the above results to be achieved even when using non-elastic core wires.
[0070] The configuration of the core feed assembly allows for better management of spinning stop and restart steps, whether using yarns with elastic or non-elastic cores.
[0071] Those skilled in the art can make various modifications and variations to the above solution to meet occasional and specific requirements.
[0072] List of reference numerals
[0073] 4: Spinning machine
[0074] 8: Air-jet spinning unit
[0075] 9: Airflow spinning chamber
[0076] 10: Yarn
[0077] 12: Fiber belt
[0078] 16: Fiber tape
[0079] 20: Core wire
[0080] 24: Drafting device
[0081] 28: Drafting roller
[0082] 36: Core wire feed assembly
[0083] 40: Yarn guide
[0084] 42: Entry point
[0085] 43: Export end
[0086] 44: Lateral wall
[0087] 48: Sliding plane
[0088] 52: Vertex
[0089] 56: Internal feed channel
[0090] 60: Entrance vertex angle
[0091] 62: Exit Vertex Angle
[0092] 68: Pre-tensioning device
[0093] 72: Feed roller
[0094] 80: Yarn clearer
[0095] 84: Clamp
[0096] 88: Wire cutter
[0097] 92: Venturi effect mouth
[0098] 92': First Venturi Effect Mouth
[0099] 92'': Second Venturi Effect Mouth
[0100] 93: Entrance Mouth
[0101] 94: Exit nozzle
[0102] XX: Draft axis
[0103] MM: Centerline Plane
[0104] TT: Tangential direction
[0105] P: Feed path.
Claims
1. A spinning machine (4) for spinning yarn (10) having a core (20), said core being elastic or inelastic, said spinning machine comprising: - A drafting device (24) comprising at least two pairs of drafting rollers (28) that are cylindrical and rotate about mutually parallel drafting axes (XX), the drafting device (24) being configured such that fibers in at least one fiber strip (12, 16) fed into the drafting device (24) along a feed path (P) become mutually parallel between the at least two pairs of drafting rollers, the at least one fiber strip (12, 16) converging across a centerline plane (MM) in the feed path. - An air-jet spinning unit (8) is arranged downstream of the drafting device (24) and includes an air-jet spinning chamber (9) configured to form yarn (10) by winding or twisting the fibers that have become parallel through the drafting device (24). - A core yarn feed assembly (36) is arranged upstream of the last pair of draft rollers in the at least two pairs of draft rollers (28), and is configured to introduce the core yarn (20) into the interior of the at least one fiber strip (12, 16), and then allow the at least one fiber strip (12, 16) to enter the interior of the air-jet spinning chamber (9) and wind around the core yarn (20). A yarn guide (40) is arranged at the entrance of the air-jet spinning unit (8). The yarn guide is designed to receive the fibers in the at least one fiber strip (12, 16) and keep the fibers parallel and separated from each other until the fibers enter the air-jet spinning chamber (9).
2. The spinning machine (4) according to claim 1 for spinning yarn (10) having a core (20), wherein, The yarn guide (40) is configured to insert the core yarn (20) between the fibers in the at least one fiber strip (12, 16) at the centerline plane (MM).
3. The spinning machine (4) for spinning yarn (10) having a core (20) according to claim 1 or 2, wherein, The yarn guide (40) includes a pair of sliding planes (48) that are inclined to each other to form a vertex (52), and the pair of sliding planes are configured to slidably guide the fibers in the at least one fiber strip (12, 16) so that the fibers remain parallel to each other.
4. The spinning machine (4) according to claim 3 for spinning yarn (10) having a core (20), wherein, The vertex (52) is located on the centerline plane (MM).
5. The spinning machine (4) for spinning yarn (10) having a core (20) according to claim 3 or 4, wherein, The sliding plane (48) is inclined in a divergent-then-convergent manner along the axial extension direction (AA) of the yarn guide (40), and extends from the inlet end (42) directly facing the at least one pair of draft rollers (28) to the outlet end (43) directly facing the airflow spinning chamber (9).
6. The spinning machine (4) for spinning yarn (10) having a core (20) according to claim 3, 4 or 5, wherein, At the inlet end (42) where the fiber enters the yarn guide (40), the vertex (52) defines an inlet vertex angle (60) between the sliding planes (48), the inlet vertex angle being between 180° and 215°, preferably between 195° and 205°.
7. The spinning machine (4) for spinning yarn (10) having a core (20) according to claim 3, 4, 5 or 6, wherein, At the exit end (43) where the fiber leaves the yarn guide (40), the vertex (52) defines an exit vertex angle (62) between the sliding planes (48), the exit vertex angle being between 120° and 150°, preferably between 130° and 140°.
8. A spinning machine (4) according to any one of claims 1 to 7 for spinning a yarn (10) having a core (20), wherein, The spinning machine (4) includes a pre-tensioning device (68) for the core yarn (20), which controls the feed speed of the core yarn (20) to apply a certain pre-tension force to the core yarn (40).
9. The spinning machine (4) according to claim 8 for spinning yarn (10) having a core (20), wherein, The pretensioning device (68) includes a feed roller (72) that can operate at a variable speed.
10. The spinning machine (4) according to claim 9 for spinning yarn (10) having a core (20), wherein, The core yarn (20) is an elastic core yarn, and wherein the feed roller (72) is operated to feed the core yarn (20) at a speed of 1 / 6 to 1 / 3 of the spinning speed, thereby applying a preload to the core yarn (20).
11. A spinning machine (4) according to any one of claims 1 to 10 for spinning a yarn (10) having a core (20), wherein, The spinning machine (4) includes a yarn clearer (80) configured to analyze the yarn (10) exiting the airflow spinning chamber (9), and wherein the core yarn feed assembly (36) includes: - At least one clamp (84) configured to selectively hold the core wire (20). - At least one wire cutter (88) configured to selectively cut the previously clamped core wire (20). - At least one Venturi effect nozzle (92) is configured to selectively generate a suction flow for drawing the core wire (20), thereby selectively generating a suction flow for drawing the core wire (20) from the inlet nozzle (93) to the outlet nozzle (94).
12. The spinning machine (4) according to claim 11 for spinning yarn (10) having a core (20), wherein, The core wire feed assembly (36) is operatively connected to the yarn clearer (80) and / or operatively associated with a release signal triggered at the end of spinning.
13. The spinning machine (4) according to claim 11 or 12 for spinning yarn (10) having a core (20), wherein, The clamp (84) and the wire cutter (88) are operatively connected to each other such that the clamp (84) is operated first to clamp the core wire (20), and then the wire cutter (88) is operated to cut the yarn (10).
14. The spinning machine (4) for spinning yarn (10) having a core (20) according to claim 11, 12 or 13, wherein, The clamp (84) and the wire cutter (88) are anchored to the same operating system.
15. A spinning machine (4) according to any one of claims 11 to 14 for spinning a yarn (10) having a core (20), wherein, The Venturi effect nozzle (92) and the clamp (84) are operatively connected to each other such that the Venturi effect nozzle and the clamp are activated simultaneously each time spinning is restarted.
16. A spinning machine (4) according to any one of claims 11 to 15 for spinning a yarn (10) having a core (20), wherein, The core wire feed assembly (36) includes two Venturi nozzles (92) configured to selectively generate a suction flow for drawing the core wire (20) into the outlet nozzle (94), wherein a first Venturi nozzle (92') of the two Venturi nozzles is positioned upstream of the holder (84), and a second Venturi nozzle (92'') of the two Venturi nozzles is positioned downstream of the holder (84).
17. The spinning machine (4) according to claim 16 for spinning yarn (10) having a core (20), wherein, The first Venturi effect nozzle (92') and the second Venturi effect nozzle (92'') are operatively connected to each other and to the clamp (84).
18. The spinning machine (4) according to claim 16 or 17 for spinning yarn (10) having a core (20), wherein, The two Venturi effect nozzles (92', 92'') are activated simultaneously, or sequentially by first activating the second Venturi effect nozzle (92'') and then activating the first Venturi effect nozzle (92').
19. A spinning machine (4) according to any one of claims 1 to 18 for spinning a yarn (10) having a core (20), wherein, The fibers in the two fiber strips (12, 16) are fed into the drafting device along the feed path (P), the two fiber strips (12, 16) converge across the centerline plane (MM) until they enter the airflow spinning chamber (9), and the core yarn is arranged at the centerline plane (MM).
20. A spinning machine (4) according to any one of claims 1 to 19 for spinning a yarn (10) having a core (20), wherein, The core wire feed assembly (36) is configured to insert the core wire (20) into the interior of at least one fiber strip (12, 16) along a tangential direction (TT) at the centerline plane (MM) and upstream of the air-flow spinning chamber (9), the tangential direction being tangential to the outer sidewall (44) of the drafting rollers in the at least one pair of drafting rollers (28) and intersecting the feed path (P).
21. The spinning machine (4) according to claim 20 for spinning yarn (10) having a core (20), wherein, The core wire feed assembly (36) includes an outlet nozzle (94) configured and / or tilted to insert the core wire (20) between the fibers in the at least one fiber strip (12, 16) along the tangential direction (TT).
22. A method for spinning a yarn with an elastic or non-elastic core, comprising the following steps: - Prepare a spinning machine (4) for spinning yarn (10) having a core (20) according to any one of claims 1 to 21. - Prepare the flexible core wire as the core wire (20). - According to the control of the feed speed of the core yarn (20), the elastic core yarn (20) is fed to the core yarn feed assembly (36) by means of the feed roller (72), and the rotation of the feed roller is controlled so that the feed roller feeds the core yarn (20) at a speed of 1 / 6 to 1 / 3 of the spinning speed, thereby applying a preload to the core yarn (20), the spinning speed being the forward speed of the fiber belt (12, 16) inside the air-flow spinning chamber (9).
23. A method for spinning a yarn with an elastic or non-elastic core, comprising the following steps: - Prepare a spinning machine (4) for spinning yarn (10) having a core (20) according to any one of claims 1 to 21. - Prepare non-elastic core wires as core wires (20). - The inelastic core wire (20) is fed to the core wire feeding assembly (36) so that the core wire (20) is fed with a controlled tension force.