Textile machine for spinning a yarn with an elastic or non-elastic core and a method for spinning a yarn with an elastic or non-elastic core

Abstract

A textile machine (4) for spinning a yarn (10) with a core (20), elastic or non-elastic, comprising stretching means (24), comprising at least two pairs of stretching rollers (28), cylindrical and rotating around stretching axes (X-X) parallel to each other, the stretching means (24) being configured to make the fibres parallel therebetween, of at least one ribbon of fibres (12,16) fed to said stretching means (24), along a feeding path (P) in which said at least one ribbon of fibres (12,16) converges straddling a centreline plane (M-M), an air spinning unit (8), arranged downstream of the stretching means (24), comprising a spinning chamber (9) configured to obtain yarn (10) by winding or twisting the fibres made parallel by said stretching means (24), a core feeding assembly (36), arranged upstream of the last pair of stretching rollers (28), configured to introduce said core (20) inside said at least one ribbon of fibres (12,16) before said at least one ribbon of fibres (12,16) enters inside the air spinning chamber (9) and is wound around said core (20). At the inlet of the air spinning unit (8) an introducer (40) is arranged, designed to receive the fibres of the at least one ribbon of fibres (12,16) and keep them parallel and separated from each other until they enter the air spinning chamber (9).

Description

FIELD OF APPLICATION

[0001] The present invention relates to a textile machine for spinning a yarn with an elastic or non-elastic core and a method for spinning a yarn with an elastic or non-elastic core.STATE OF THE ART

[0002] The present invention arises with the aim of overcoming the current known limitations in air spinning machines for making core yarns, (in particular with an elastic core but not only) and improving the quality of the yarn produced.

[0003] It should be noted that 'elastic core' means an elastic fibre, for example an elastic polyurethane, an elastomeric polyurethane, an elastic synthetic fibre, such as elastane, Lycra, Dorlastan, Spandex. Elastic core means a core having an elongation at break greater than 100%.

[0004] Non-elastic core means a yarn which does not have significant elastic elongation at break properties; in general, non-elastic core means a core having an elongation at break less than 100%.

[0005] Air-jet spinning technology, applied to (elastic or non-elastic) core yarns, has some technical limitations which remain unresolved. The main problem relates to the guiding and positioning of the (elastic or non-elastic) core or monofilament, in the centre of the fibres so that they can completely cover it. In fact, if the core is missing or partially covered, an aesthetically unsuitable yarn will be obtained for common uses which will in fact be defective.

[0006] An example of an aesthetically defective core yarn is shown in Figure 1a, where said core is at least partially visible from the outside, while Figure 1b shows the correct positioning of the completely covered core inside the yarn so as not to be visible from the outside.

[0007] There are solutions of the art, for example in accordance with US5647197 A, which include twisted introducers to allow the fibres to converge compactly at the exit point to improve spinning: however, such solutions do not ensure the maintenance of the position of the core which is often at least partially uncovered, as in the case of Figure 1a.

[0008] The need is therefore felt to resolve the defects and limitations related to the solutions of the prior art.

[0009] Such a need is met by a textile machine for spinning a yarn with an elastic or non-elastic core in accordance with claim 1 and by a method for spinning a yarn with an elastic or non-elastic core in accordance with claim 22 or 23.DESCRIPTION OF THE DRAWINGS

[0010] Further features and advantages of the present invention will be more clearly comprehensible from the description given below of preferred and non-limiting embodiments thereof, in which: Figure 1a shows a perspective view of a defective yarn, according to the prior art; Figure 1b shows the view of a yarn obtained according to a textile machine in accordance with the present invention; Figure 2 shows a side view of a textile machine in accordance with a possible embodiment of the present invention; Figure 3 shows an enlarged detail, partially in section, of the textile machine of Figure 2; Figures 4a-4b show perspective views, from different angles, of ribbons of fibres associated with a feeding assembly and an introducer in accordance with an embodiment of the present invention; Figure 5 shows a side view of the feeding assembly and introducer of Figures 4a-4b; Figure 6 shows a top plan view of the feeding assembly and introducer of Figures 4a-4b; Figure 7 shows the enlarged detail VII of figure 6; Figure 8 shows the enlarged detail VIII of figure 6; Figure 9 shows a perspective schematic view of an introducer in accordance with an embodiment of the present invention; Figures 10-11 show sectional view of an introducer assembly in accordance with different embodiments of the present invention; Figures 12-14 show sectional views of a core feeding assembly in accordance with different embodiments of the present invention; Figures 15-17 show a sequence of gripping and cutting steps of the yarn carried out by a core feeding assembly in accordance with an embodiment of the present invention; Figure 18 shows a sectional view of the coupling portion of the introducer in the air spinning unit.

[0011] The elements or parts of elements common to the embodiments described below will be indicated using the same reference numerals.DETAILED DESCRIPTION

[0012] With reference to the aforesaid figures, reference numeral 4 globally indicates an overall schematic view of a textile machine in accordance with the present invention, in particular an air spinning textile machine of the 'air-jet spinning' type.

[0013] It should be noted that the term thread or single thread or continuous thread refers to a single filament or continuous filament (for example in the case of silk, artificial or synthetic fibres), while the term yarn refers to a group of fibrils of varying lengths which are made parallel and joined together by twisting. Hereinafter, one or the other term will be used indifferently, it being understood that the applications of the present invention are not limited to one or the other type.

[0014] The textile machine 4 comprises an air spinning unit 8, of known type, configured to obtain yarn 10 starting from at least one ribbon of fibres, preferably from two ribbons of fibres 12,16 which is subjected to a preventive action of stretching the fibres. In particular, said air spinning unit 8 comprises a spinning chamber 9 configured to wind the fibres in input and obtain the yarn 10 in output.

[0015] At the exit of the stretching step, it is necessary to introduce a core 20, i.e., an elastic or non-elastic filament inside said fibres.

[0016] Thereby, after the stretching step the fibres are parallel to each other and are therefore ready to be wound or twisted around said core 20, whether it consists of an elastic filament or it consists of a non-elastic filament.

[0017] The textile machine 4 for air spinning therefore comprises stretching means 24, comprising at least one pair of stretching rollers 28, cylindrical and rotating around stretching axes X-X parallel to each other. In general, the stretching means 24 comprise a plurality of pairs of stretching rollers 28, rotating around mutually parallel stretching axes X-X. Figures 2, 4a, 4b, 5,6 show four pairs of stretching rollers 28.

[0018] As mentioned, the stretching means 24,28 are configured to make the fibres of at least one ribbon of fibres parallel, for example two ribbons of fibres 12,16, fed to said stretching means 24, along a feeding path P in which said ribbons of fibres 12,16 converge from opposite parts with respect to a centreline plane M-M. In the case of only one ribbon of fibres 12,16, the latter converges straddling said centreline plane M-M.

[0019] The textile machine 4 comprises, as seen, an air spinning unit 8, arranged downstream of the stretching means 24, configured to obtain yarn 10 by winding or twisting the fibres made parallel by said stretching means 24.

[0020] The textile machine 4 further comprises a core feeding assembly 36, arranged upstream of the air spinning unit 8, configured to introduce said core 20 between the fibres of said at least one ribbon of fibres 12,16 before fibres of said at least one ribbon of fibres 12,16 enter inside the air spinning unit 8 and are wound around said core 20.

[0021] In particular, said core feeding assembly 36 comprises an outlet nozzle 94 configured and / or inclined so as to insert said core 20 between the fibres of said at least one ribbon of fibres 12, 16 along a tangential direction T-T, tangent with respect to an outer side wall 44 of a stretching roller of said at least one pair of stretching rollers 28, and incident with said feeding path P, at the centreline plane M-M, and upstream of the air spinning unit 8.

[0022] Downstream of the outlet nozzle 94 and at the inlet of the air spinning unit 8 an introducer 40 is arranged, designed to receive the fibres of the at least one ribbon of fibres 12,16 and keep them parallel and separated from each other until they enter the spinning chamber 9. Furthermore, the introducer 40 is configured to insert said core 20 between said fibres of the at least one ribbon of fibres 12,16, at the centreline plane M-M.

[0023] In other words, the introducer 40 is configured so as to accompany the fibres of the at least one ribbon of fibres 12,16 which are parallel, and therefore not intertwined, with each other, until they enter the spinning chamber 9 where the yarn 10 will then be formed.

[0024] In the case of using two ribbons of fibres 12,16, these are fed to the introducer 40 parallel and separated from each other, from opposite parts of said centreline plane M-M, until they enter the spinning chamber 9, inserting the core 20 between the ribbons of fibres 12,16, at said centreline plane M-M. Therefore, also in this case the fibres remain parallel to each other and parallel to the core 20, without being intertwined, until they enter the air spinning unit 8 where the yarn 10 will then be formed.

[0025] In accordance with an embodiment, said introducer 40 comprises a pair of sliding planes 48, inclined in the direction of each other so as to form a vertex 52 and configured to slidingly guide the two ribbons of fibres 12,16, keeping the two flows of fibres parallel and separated.

[0026] Preferably said vertex 52 lies on the centreline plane M-M.

[0027] In accordance with an embodiment, the sliding planes 48 are inclined in a divergent and convergent direction along an axial extension A-A of the introducer 40, from an inlet end 42 directly facing the stretching roller 28, to an outlet end 43 directly facing the spinning chamber 9.

[0028] In accordance with an embodiment, thanks to said convergent and divergent inclination, at the inlet end 42 where the fibres enter the introducer 40, the vertex 52 defines, between the sliding planes 48, an angle at the inlet vertex 60 comprised between 145° and 180°, preferably comprised between 155° and 165°.

[0029] Furthermore, at the outlet end 43 in which the fibres exit from the introducer 40, the vertex 52 defines, between the sliding planes 48, an angle at the exit vertex 62 comprised between 120° and 150°, preferably comprised between 130° and 140°.

[0030] In accordance with an embodiment, the textile machine 4 comprises a pre-tensioning device of the elastic core 20 which includes a feeding system which controls the insertion speed thereof inside the core feeding assembly 36.

[0031] In accordance with an embodiment, said feeding system includes a feeding roller 72 operable with variable speed.

[0032] Preferably, if said core 20 is an core 20, said feeding roller 72 is operated so as to feed the core 20 at a speed 3 to 6 times lower than the spinning speed, i.e., the advancement speed of said ribbons of fibres 12,16 inside the air spinning unit 8, so as to exert a pre-loading action on the core 20.

[0033] In accordance with an embodiment, the textile machine 4 comprises a clearer 80 configured to analyse the yarn 10 exiting the air spinning unit 8.

[0034] In accordance with an embodiment, the core feeding assembly 36 further comprises: at least one gripper 84 configured to selectively retain said core 20, at least one scissor 88, configured to selectively cut the previously gripped core 20, at least one Venturi-effect nozzle 92 configured to selectively create a suction flow for sucking the core 20 from an inlet nozzle 93 to an outlet nozzle 94.

[0035] In accordance with an embodiment, the core feeding assembly 36 is operatively connected to the clearer 80 and / or to a release signal which is activated at the end of spinning. Thereby, the core feeding assembly 36 can be operated as a function of the detection of a defect by the clearer 80 and / or as a function of the end of the spinning, or of the depletion of the ribbons.

[0036] In accordance with an embodiment, the gripper 84 and the scissor 88 are operatively connected to each other so as to operate first the gripper 84, so as to grip the core 20, and then the scissor 88 for cutting the yarn 10.

[0037] In particular, the step of gripping the yarn 10 is illustrated in the Figures 12,13,14 in sequence. The next cutting step is illustrated in Figures 15,16,17.

[0038] In accordance with an embodiment, the gripper 84 and the scissor 88 are anchored to a same operating piston.

[0039] In accordance with an embodiment, the nozzle 92 and the gripper 84 are operatively connected to each other so as to be activated simultaneously with each restart of the spinning.

[0040] That is, during the restart step, it is essential to simultaneously activate both the gripper 84 and the (Venturi) air flow obtained through said Venturi-effect nozzle 92, to ensure the correct positioning of the core 20 in the outlet nozzle 94.

[0041] The synchronisation is crucial, in particular to compensate for the high elastic tension of the core 20: if the cutting of the yarn 10 occurs before the activation of the nozzle 92 and therefore of the Venturi flow, there is a risk of a withdrawal of the yarn 10; on the contrary, if the nozzle 92 and therefore the Venturi flow is started before the cutting operated through the scissor 88, a tangling of the yarn 10 could occur, especially if the core 20 is of elastic type.

[0042] It is therefore essential to activate the airflow, for a time such as to introduce the core 20 first in the outlet nozzle 94 and just afterwards, centrally to the ribbons of fibres 12,16.

[0043] In accordance with a possible variant embodiment, the core feeding assembly 36 comprises two Venturi-effect nozzles 92 configured to selectively create a suction flow for sucking the core 20, in particular a first Venturi-effect nozzle 92' is arranged upstream of the gripper 84 and a second Venturi-effect nozzle 92'' is arranged downstream of the gripper 84.

[0044] In particular, the suction only occurs at the level of the two Venturi-effect nozzles 92' and 92", and the Venturi effect is activated to slide the core 20 inside the outlet nozzles 94, respectively.

[0045] The activation of the two Venturi-effect nozzles 92',92" can occur simultaneously or sequentially by activating first the second Venturi-effect nozzle 92" and subsequently the first Venturi-effect nozzle 92'. This is to avoid the accumulation of core 20 between the inlet nozzle 93 and the outlet nozzle 94.

[0046] As may be appreciated from the description, the present invention makes it possible to overcome the drawbacks mentioned of the prior art.

[0047] In particular, the present invention, with respect to the solutions of the prior art, allows to position the core inside the yarns in a precise and repeatable manner, both in the case of elastic yarn and in the case in which the yarn is of the elastic type.

[0048] The tangential inclination of the core inside the ribbons of fibres, previously made parallel and separated from each other, allows to obtain the optimal positioning of the core inside the yarn so as to wrap and cover the core symmetrically and completely with the fibres of the ribbons. Thereby, the yarn obtained will be aesthetically suitable as the core will be perfectly hidden by the fibres wrapped around it.

[0049] The particular geometric configuration of the introducer allows to keep the fibres of the ribbons parallel and separated from each other until they enter the spinning chamber.

[0050] Advantageously, the invention allows to obtain the aforementioned results even in the case of using non-elastic cores.

[0051] The configuration of the core feeding assembly allows to better manage the stopping and restarting steps of the spinning both with the use of yarns with elastic core and in the case of yarns with non-elastic core.

[0052] A person skilled in the art may make numerous modifications and variations to the solutions described above so as to satisfy contingent and specific requirements.

[0053] The scope of protection of the present invention is defined by the following claims.List of references

[0054] 4: textile machine 8: air spinning unit 9: spinning chamber 10: yarn 12: ribbon of fibres 16: ribbon of fibres 20: core 24: stretching means 28: stretching roller 36: core feeding assembly 40: introducer 42: inlet end 43: outlet end 44 outer lateral wall 48: sliding planes 52: vertex 56: internal feeding channel 60: angle at the inlet vertex 62: angle at the exit vertex 68: pre-tensioning device 72: feeding roller 80: clearer 84: gripper 88: scissor 92: Venturi-effect nozzle 92': first Venturi-effect nozzle 92": second Venturi-effect nozzle 93 inlet nozzle 94: outlet nozzle X-X: stretching axis M-M: centreline plane T-T: tangential direction P: feeding path

Claims

1. Textile machine (4) for spinning a yarn (10) with a core (20), elastic or non-elastic, comprising: - stretching means (24), comprising at least two pairs of stretching rollers (28), cylindrical and rotating around stretching axes (X-X) parallel to each other, the stretching means (24) being configured to make the fibres parallel therebetween, of at least one ribbon of fibres (12,16) fed to said stretching means (24), along a feeding path (P) in which said at least one ribbon of fibres (12,16) converges straddling a centreline plane (M-M), - an air spinning unit (8), arranged downstream of the stretching means (24), comprising a spinning chamber (9) configured to obtain yarn (10) by winding or twisting the fibres made parallel by said stretching means (24), - a core feeding assembly (36), arranged upstream of the last pair of stretching rollers (28), configured to introduce said core (20) inside said at least one ribbon of fibres (12,16) before said at least one ribbon of fibres (12,16) enters inside the air spinning chamber (9) and is wound around said core (20), wherein at the inlet of the air spinning unit (8) an introducer (40) is arranged, designed to receive the fibres of the at least one ribbon of fibres (12,16) and keep them parallel and separated from each other until they enter the air spinning chamber (9).

2. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 1, wherein the introducer (40) is configured to insert said core (20) between said fibres of the at least one ribbon of fibres (12,16), at the centreline plane (M-M).

3. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 1 or 2, wherein said introducer (40) comprises a pair of sliding planes (48), inclined to each other so as to form a vertex (52) and configured to slidingly guide the fibres of said at least one ribbon of fibres (12,16), keeping the fibres parallel to each other, wherein said vertex (52) lies on the centreline plane (M-M).

4. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 3, wherein the sliding planes (48) are inclined in a divergent and convergent direction along an axial extension (A-A) of the introducer (40), from an inlet end (42) directly facing said at least one pair of stretching rollers (28), to an outlet end (43) directly facing the air spinning chamber (9).

5. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 3 or 4, wherein at the inlet end (42) in which the fibres enter the introducer (40), the vertex (52) defines, between the sliding planes (48), an angle at the inlet vertex (60) comprised between 145° and 180°, preferably comprised between 155° and 165°.

6. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 3, 4 or 5, wherein, at the outlet end (43) in which the fibres exit from the introducer (40), the vertex (52) defines, between the sliding planes (48), an angle at the exit vertex (62) comprised between 120° and 150°, preferably comprised between 130° and 140°.

7. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 6, wherein the textile machine (4) comprises a pre-tensioning device (68) of the core (20) which controls the feeding speed of the core (20) to confer a certain pre-tensioning of the core (40), wherein said pre-tensioning device (68) includes a feeding roller (72) operable with variable speed, wherein said core (20) is an elastic core and wherein said feeding roller (72) is operated so as to feed the core (20) at a speed 3 to 6 times lower than the spinning speed, so as to exert a pre-loading action on the core (20).

8. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 7, wherein the textile machine (4) comprises a clearer (80) configured to analyse the yarn (10) exiting from the air spinning chamber (9) and wherein the core feeding assembly (36) comprises: - at least one gripper (84) configured to selectively retain said core (20), - at least one scissor (88), configured to selectively cut the previously gripped core (20), - at least one Venturi-effect nozzle (92) configured to selectively create a suction flow for sucking the core (20) to selectively create a suction flow for sucking the core (20) from an inlet nozzle (93) to an outlet nozzle (94), wherein the core feeding assembly (36) is operatively connected to the clearer (80) and / or to a release signal which is activated at the end of spinning.

9. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 8, wherein the gripper (84) and the scissor (88) are operatively connected to each other so as to operate first the gripper (84), so as to grip the core (20), and then the scissor (88) for cutting the yarn (10).

10. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 8 to 9, wherein the Venturi-effect nozzle (92) and the gripper (84) are operatively connected to each other so as to be activated simultaneously with each restart of the spinning.

11. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 8 to 10, wherein the core feeding assembly (36) comprises two Venturi-effect nozzles (92) configured to selectively create a suction flow for sucking the core (20) inside the outlet nozzle (94), wherein a first Venturi-effect nozzle (92') is arranged upstream of the gripper (84) and a second Venturi-effect nozzle (92'') is arranged downstream of the gripper (84).

12. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 11, wherein said first Venturi-effect nozzle (92') and second Venturi-effect nozzle (92") are operatively connected to each other and to the gripper (84).

13. Textile machine (4) for spinning a yarn (10) with a core (20) according to claim 11 or 12, wherein the activation of the two Venturi-effect nozzles (92',92") occurs simultaneously or sequentially by activating first the second Venturi-effect nozzle (92") and subsequently the first Venturi-effect nozzle (92').

14. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 13, wherein the stretching means are fed with the fibres of two ribbons of fibres (12,16) along said feeding path (P), said two ribbons of fibres (12,16) converging straddling said centreline plane (M-M), until entering said spinning chamber (9), said core being arranged at said centreline plane (M-M).

15. Textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 14, wherein said core feeding assembly (36) is configured so as to insert said core (20) along a tangential direction (T-T), tangent with respect to an outer side wall (44) of a stretching roller of said at least one pair of stretching rollers (28), and incident with said feeding path (P), inside said at least one ribbon of fibres (12,16), at the centreline plane (M-M), and upstream of the air spinning chamber (9), wherein said core feeding assembly (36) comprises an outlet nozzle (94) configured and / or inclined so as to insert said core (20) between the fibres of said at least one ribbon of fibres (12,16) along said tangential direction (T-T).

16. Spinning method of a yarn with an elastic or non-elastic core comprising the steps of: - preparing a textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 15, - preparing an elastic core as core (20), - feeding said elastic core (20) to the core feeding assembly (36) by means of a feeding roller (72) according to a control of the feeding speed of the core (20), said feeding roller being controlled in rotation so as to feed the core (20) at a speed 3 to 6 times lower than the spinning speed, i.e., the advancement speed of said ribbons of fibres (12,16) inside the air spinning chamber (9), so as to exert a pre-loading action on the core (20).

17. Spinning method of a yarn with an elastic or non-elastic core comprising the steps of: - preparing a textile machine (4) for spinning a yarn (10) with a core (20) according to any one of claims 1 to 15, - preparing a non-elastic core as core (20), - feeding said non-elastic core (20) to the core feeding assembly (36) so as to feed the core (20) with a controlled tension.

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