A process for spinning fancy yarn, machine for spinning fancy yarn with said process and fancy yarn produced with said process

Abstract

 Method for spinning fancy yarns (16) comprising the steps of: a) injecting continuously a bundle (3) of base fibres to a drafting train (1) of said bundle (3) of base fibres, b) when said bundle (3) of base fibres is continuously injected, injecting intermittently a bundle (10) of effect fibres to said same drafting train (1) to add intermittently said bundle (10) of effect fibres to said bundle (3) of base fibres, and each intermittent injection of effect fibres of step b) includes the steps of: bi) advancing a stretch of said bundle (10) of effect fibres to the drafting train (1) of said bundle (3) of base fibres, and bii) then, moving backwardly said stretch a preset length, said backward movement permitting the forced cutting or separation of a fragment of bundle (10) of effect fibres to be added to the bundle (3) of base fibres in said drafting train (1). The fancy yarn (16) manufactured by the method comprises a plurality of fragments of a bundle (10) of effect fibres added in a discontinuous way to a bundle (3) of base fibres. The formation of said fragments permits the fibres to be added as more compact groups to the bundle of base fibres, which enhances the effect of added fibres and also the quality of the obtained yarn.

Description

[0001] The present invention refers to a method and to a machine for spinning fancy yarns. It also refers to a fancy yarn manufactured by said method including fibres for adding effect inserted between the base fibres of said yarn.

BACKGROUND OF THE INVENTION

[0002] It is known to produce fancy yarns by the intermittent addition of one of several bundles of effect fibres of different colours or nature to a bundle of base fibres.

[0003] WO2011/018685 discloses a production method of fancy yarn in which the base fibres and the effect fibres are drafted separately to obtain a preset thickness, converging then the different bundles at a torsion spindle to form the yarn.

[0004] The fancy yarn manufactured by the method of said patent has the advantage that the desired contrast effect is obtained adding fibres of different nature or colour. However, this contrast effect can be enhanced applying a method such as that disclosed in CN1336453.

[0005] CN1336453 discloses a method for manufacturing a fancy yarn having the particularity that the bundles of effect fibres are added to the bundle of base fibres during the drafting step of said bundle of base fibres, all the fibres together obtaining the torsion. Specifically, the claimed method comprises a step of injecting continuously a bundle of base fibres in a drafting train of said bundle of base fibres, and the step of inj ecting intermittently a bundle of effect fibres at said same drafting train when the bundle of base fibres is injected continuously.

[0006] The fancy yarn of patent CN1336453 has an enhanced chromatic contrast because during the drafting step the effect fibres are joined and are combined completely with the base fibres. However, this fancy yarn has some features that can be enhanced.

[0007] E.g. it has been observed that in the yarn of patent CN1336453 the linear mass of aggregated fibres in each intermittent injection changes a lot from one injection to another, also resulting difficult to control the injection place of said fibres. On the other hand, it has been observed that the yarn manufactured by the method of CN1336453 has a great quantity of effect fibres that can be broken easily because they are not suitably joined to the base fibres.

DESCRIPTION OF THE INVENTION

[0008] A first object of the present invention is to solve said drawbacks, providing a method and a machine for spinning fancy yarns presenting the advantages that will be described hereinafter.

[0009] A second object of the present invention is to solve said drawbacks, developing a fancy yarn with a high quality.

[0010] According to these objects, according to a first aspect, the present invention provides a method for spinning fancy yarns comprising the steps of:

a) injecting continuously a bundle of base fibres to a drafting train of said bundle of base fibres,

b) while said bundle of base fibres is continuously injected, injecting intermittently a bundle of effect fibres to said same drafting train to add intermittently said bundle of effect fibres to said bundle of base fibres, and it is characterised in that each intermittent inj ection of effect fibres of step b) includes the steps of:

bi) advancing a stretch of said bundle of effect fibres to the drafting train of said bundle of base fibres, and

bii) then, moving backwardly said stretch a preset length, said backward movement permitting the forced cut or separation of a fragment of bundle of effect fibres to be added to the bundle of base fibres in said drafting train.

[0011] According to a second aspect, the present invention provides a machine for spinning fancy yarns comprising a fibre drafting train provided, at each spinning position, with injection means of a bundle of base fibres and injection means of a bundle of effect fibres, said means for injecting effect fibres being associated to said means for injection base fibres, so that said bundle of base fibres is susceptible of being added intermittently to said bundle of base fibres in the same drafting train, and it is characterized in that said means for injecting effect fibres are configured to permit the backward movement of a stretch of said bundle of effect fibres when said means for inj ecting effect fibres receives a backward movement signal from a processing and control unit of said machine, that is configured to carry out the claimed method, the backward movement of said stretch permitting the forced cut or separation of a fragment of bundle of effect fibres to be added to the bundle of base fibres in the same drafting train.

[0012] According to a third aspect, the present invention provides a fancy yarn manufactured by the claimed method that is characterized in that it comprises a plurality of fragments of a bundle of effect fibres added in a discontinued way to a bundle of base fibres.

[0013] In the present invention, by fragment of a bundle of effect fibres is meant a stretch of a bundle of fibres for adding effect that has a substantially uniform linear mass of fibres.

[0014] The claimed method has the advantage with respect to the method of CN1336453 that the effect fibres are added to the bundle of base fibres in a very controlled way.

[0015] Actually, in the method of the present invention, the injection of effect fibres is carried out so that the drafting train of base fibres advances a stretch of the bundle of effect fibres and then, moves backwardly said stretch a preset length to permit the forced cut or separation of a fragment of the bundle of effect fibres. Thanks to this forced cut or separation, the addition of effect fibres is stopped at the desired moment, which positively impacts on the control and quality of the obtained fancy yarn. This is because the formation of said fragment prevents the injection of more fibres in the same bundle.

[0016] In the prior art, differently from what happens in the present invention, as said backward movement forcing the formation of fragments is not present, it is impossible to stop immediately the addition of effect fibres, because the stop of the advancement of the bundle of effect fibres does not prevent loose fibres from said bundle to be added.

[0017] Another advantage of the claimed method is that the formation of said fragments permits the fibres to be added in more compact groups to the bundle of base fibres, which enhances the effect of the added fibres and also the quality of the obtained yarn.

[0018] Preferably, in step bii), the backward movement of said stretch of effect fibres is done at a speed higher than the injection speed of the bundle of base fibres that are added to the effect fibres.

[0019] It has been observed that if the backward movement speed of the stretch of effect fibres is higher than the injection speed of the bundle of base fibres, the cut or separation of said fragments is done more effectively (a cut more sharp and clean).

[0020] Again preferably, in step bi), said bundle of effect fibres is inserted in the drafting train at a speed which is the same or lower than the injection speed of the bundle of base fibres.

[0021] According to a preferred embodiment of the method, after each injection of step b) the following step is carried out:

c) acceleration of the injection speed of the bundle of base fibres for producing a slubby in said bundle of base fibres, said acceleration being done at the moment in which said fragment of bundle of effect fibres is added to the base fibres, the injection place of said fragment matching with said slubby.

[0022] In the present invention slubby means an over-thickness of base fibres of a yarn produced by the accumulation of fibres by a punctual reduction of the drafting ratio of the bundle of base fibres.

[0023] It has been observed that the accumulation of base fibres producing the slubby makes easier the control of the injection of the effect fibres, because it forces the massive exit of the added effect fibres. Therefore, the length of the additions is more regular (shorter and more compact) than those from the state of the art. Furthermore, it has been observed that the slubby enhances the effect of the effect fibres and makes easier their holding, which prevents said effect fibres to be loosened or broken easily, as in the yarns of the state of the art.

[0024] Advantageously, said acceleration is done at the moment in which said fragment is placed in a drafting bag of the drafting train of said bundle of base fibres.

[0025] It has been observed that this moment is the more suitable moment to control with a greater efficiency the length and thickness of the additions of effect fibres in the resulting yarn.

[0026] Preferably, according to said preferred embodiment, in step c), said injection speed of the bundle of base fibres is accelerated a preset time according to the desired length of the slubby, and a preset value according to the desired thickness of the slubby.

[0027] It has been observed that the length and the thickness of the slubby can be controlled by a program that determines the acceleration value and time that is applied. Furthermore, it must be pointed out that the control of the length and thickness of the slubby involves itself a control of the length and thickness of the additions of effect fibres in the resulting yarn.

[0028] As stated previously, the present invention also provides a spinning machine, particularly a continuous spinning machine, which has the advantage that permits to carry out said method.

[0029] The claimed spinning machine has the particularity that the drafting train of the fibres has injection means of the effect fibres that are configured to permit the backward movement of a stretch of said bundle of effect fibres when said fibre inj ecting means receives a backward movement signal from a processing and control unit that carries out the claimed method. This backward movement of the bundle of effect fibres produced by the injection means of effect fibres permits the forced cut or separation of a fragment of said bundle that is provided to be added to the bundle of base fibres.

[0030] Preferably, said inj ection means of a bundle of effect fibres includes, in each spinning position, at least a first pair of rollers between which said bundle of effect fibres extends when said machine is operating, said rollers being able to rotate in both directions to permit the advancement or backward movement of said bundle of fibres, and said injection means of a bundle of base fibres include, at each spinning position, at least a second pair of rollers between which said bundle of base fibres extends when said machine is operating, said injection rollers of base fibres being placed according to the injection rollers of effect fibres to permit the intermittent addition of fragments of a bundle of effect fibres to a bundle of base fibres passing by said second pair of rollers.

[0031] Advantageously, said machine comprises fibre drafting belts associated with said second pair of rollers, said belts determining a fibre drafting bag of said drafting train.

[0032] According to a preferred embodiment, the drafting train of the machine comprises, at the spinning position, a condenser element configured as a funnel arranged between said injecting means of effect fibres and said injecting means of base fibres, said condenser covering substantially the distance from the means for injecting effect fibres to the means for injecting base fibres to make easier the joining of said fragment of the bundle of effect fibres with the bundle of base fibres.

[0033] It has been observed that, as the condenser covers the distance from the injecting means of the effect fibres to the injecting means of the base fibres, the feeding continuity of the fibre assembly is guaranteed, even with the intrinsic discontinuity in the feeding because of the formation of fragments of the bundle of effect fibres.

[0034] Advantageously, said condenser element comprises a first inlet stretch as a mouth to join said fragment and said bundle of base fibres from one side to the other, and a second outlet stretch as a tunnel to merge or join said fragment with said bundle of base fibres.

[0035] This shape of the condenser guarantees the feeding efficiency of the fibres to the drafting bag of the machine.

[0036] According the same preferred embodiment, the drafting train of said machine comprises, at each spinning position, supporting means of said condenser as a funnel, said supporting means including:

• a first support piece on which said condenser is fixed, said piece being able to be moved horizontally, and
• a second support piece of said first piece, said second piece including a support strip that is joined to a chassis of said machine, said strip permitting the lateral movement of said first piece.

[0037] Said support strip has the following functions. On one hand, as it is joined to the chassis of the machine, it supports the first piece on which the condenser is fixed and prevents its undesired vertical movement. On the other hand, acting as a spring, it permits the horizontal movement of the piece on which the condenser is fixed, preventing the overcharge of the motor driving said piece.

[0038] The horizontal movement of the condenser and with it the fibre bundle passing by said fibre injecting means is necessary to prevent the premature wear of said means.

[0039] According to the same preferred embodiment, the drafting train comprises, at each spinning position, a condenser element configured as a floating wedge, said condenser being placed floating at the outlet of a drafting bag associated with said inj ecting means of base fibres, permitting said floating condenser to unite the assembly of effect fibres and base fibres before their torsion.

[0040] It has been observed that the floating condenser as a wedge can be placed at the outlet of the drafting bag associated with the injecting means of the base fibres, not being necessary to change the position of said means or the position of the drafting bag itself, as in the machine of the state of the art.

[0041] Actually, the machines of the state of the art use a condenser with a funnel shape at the outlet of the drafting bag. This condenser and the element that supports it occupy a space that is necessary to be obtained changing the position of the injecting means of the base fibres or of the drafting bag itself, which involves a loss of control of the quality of the yarn at the moment previous to the torsion. However, the condenser with a floating wedge shape of the present invention occupies very little space, so that it can be placed at the outlet of the drafting bag with no necessity of changing the position of said bag or the injecting means of base fibres.

[0042] Preferably, the drafting train of said machine comprises, at each spinning position, means for holding said condenser as a floating wedge, said means including a support rod horizontally movable on a pressure arm including rollers of said drafting train.

[0043] This support rod and the floating condenser itself are horizontally moved by the movement of the bundle of fibres itself at the outlet of the drafting bag of the machine and they occupy a very little space in the machine.

[0044] As stated previously, according to a third aspect, the present invention provides a fancy yarn manufactured by the claimed method presenting the particularity that it comprises a plurality of fragments of a bundle of effect fibres added in a discontinued way to a bundle of base fibres.

[0045] Differently from the fancy yarn of the state of the art, the additions of the effect fibres to the yarn of the present invention are formed from fragments of a bundle of fibres, so that they present a more uniform and compact aspect that considerably enhances the effect of the added fibres, and also the final quality of the obtained yarn. However, the additions of the effect fibres of the yarns of the state of the art have an irregular aspect, and also a great quantity of loose fibres that can be broken easily.

[0046] Preferably, said fancy yarn comprises a plurality of slubbies of said bundle of base fibres, each of said slubbies including said fragments of a bundle of effect fibres.

[0047] As stated previously, thanks to the slubby, the length of the additions of effect fibres is more regular (more uniform and compact) than those of the state of the art. Furthermore, it has been confirmed that the slubby improves the effect of the effect fibres and makes easier its holding, which prevents said effect fibres to be loosened or broken easily, as with the yarns of the state of the art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] For a better understanding of what has been disclosed some examples are attached, in which diagrammatically and only as a non limitative example, a practical case of embodiment is shown.

[0049] In said drawings,

Fig. 1 shows a side view of a drafting train of a machine for spinning fancy yarn of the state of the art.

Fig. 2 shows a side view of a drafting train of a preferred embodiment of a spinning machine of the present invention.

Fig. 3 shows a perspective view of the drafting train of Fig. 2.

Fig. 4 is an upper perspective view of the drafting train of Fig. 2 in which the upper rollers from the third line of rollers have been removed to see the detail of the floating wedge condenser.

Fig. 5 is a rear perspective view of the drafting train of Fig. 2.

Fig. 6 shows a view and a detail of a fancy yarn obtained with the claimed method.

DESCRIPTION OF A PREFERRED EMBODIMENT AND OF AN EXAMPLE OF OPERATION

[0050] As shown in Fig. 1 and as it is currently known, the drafting train 1 of a continuous spinning machine of the state of the art includes three lines or pairs of rollers 2a, 2b, 2c between which, in each spinning position, a bundle 3 of base fibres extends. These pairs of rollers 2a, 2b, 2c rotate at different speeds and with the same rotation direction, and they are normally linked to each other by a gear transmission system.

[0051] Just one bundle 3 of base fibres extends through said three pairs of rollers 2a, 2b, 2c, and for each spinning position, which, when is subjected to increasing rotation speeds of said rollers 2a, 2b, 2c, produces a drafting of said bundle 3 so that its linear mass is decreased until a preset limit for forming a simple yarn with a determined thickness is reached. At the outlet of the last pair of rollers 2c, the fibres already drafted from the bundle 3 enter in a torsion spindle (not shown).

[0052] The lower rollers of each pair of rollers 2a, 2b, 2c are configured by cylinders that are mounted on trestles 4 that also support a bar 5 on which pressure arms 6 are mounted (one arm 6 for each two spinning positions). These pressure arms 6 have the function of placing and holding applying pressure the upper rollers of the three lines of rollers (the rear one 2a, the intermediate one 2b and the frontal one 2c) on their respective lower rollers.

[0053] As shown in the same Fig. 1, the drafting train 1 of the state of the art also includes, for each spinning position, condensers 7 that have the function of guiding the bundle 3 of base fibres when it enters to the first pair 2a of rollers, and drafting belts 8 placed between the second 2b and the third 2c pair of rollers. These drafting belts 8 determine what is commonly defined as a fibre-drafting bag 9.

[0054] Hereinafter one embodiment of the spinning machine and the method of the present invention are described, making reference to Figs. 2-5.

[0055] The machine of the present invention comprises a drafting train 1 that presents the particularity that, at each spinning position, the first pair 2a of rollers is responsible of inj ecting a bundle 10 of effect fibres, being the second pair 2b of rollers that which injects now the bundle 3 of base fibres.

[0056] In the disclosed machine, the first pair 2a of rollers, which constitute what in the present specification has been identified as means for injecting a bundle 10 of effect fibres, is driven by a servomotor through a processing and control unit that is programmed to inject intermittently the bundle 10 of effect fibres to the bundle 3 of base fibres. This injection of the effect fibres is done during the continuous injection of said bundle 3 of base fibres through the second pair 2b of rollers that is driven by a second servomotor associated with the same processing and control unit.

[0057] As stated previously in the description of the invention, in the claimed method the injection of effect fibres is done advancing a stretch of the bundle 10 of effect fibres 10, and then moving back said stretch a preset length to permit the forced cut or separation of a fragment of the bundle 10 of the effect fibres to be added to the bundle 3 of base fibres. Thanks to this forced cut or separation, the addition of effect fibres is stopped at the desired moment, which positively impacts on the control and quality of the obtained fancy yarn.

[0058] To carry out said backward movement of the stretch of effect fibres, the first pair 2a of rollers is configured to rotate in a direction opposed to the advance direction, when the servomotor that drives said rollers 2a receives a backward movement signal from said processing and control unit.

[0059] In the disclosed embodiment, the processing and control unit has been programmed so that the backward movement of the bundle 10 of effect fibres is done at a speed that is higher than the injection speed of the bundle 3 of base fibres, because it has been observed that the cut or separation of the fragments is done in a more efficient way (a cut more sharp and clean).

[0060] Turning back to the same processing and control unit of the machine, it must be pointed out that this unit has been programmed to accelerate the injection speed of the bundle 3 of base fibres (speed of the second pair 2b of rollers) just at the moment in which a fragment of one bundle 10 of effect fibres is added in the drafting bag 9 to the bundle 3 of base fibres. Therefore, the injection place of said fragment matches with a slubby produced because of this acceleration.

[0061] The accumulation of fibres that produces the slubby (drafting reduction) has the advantage that makes easier the control of the length and the thickness of the injection of effect fibres, increases the effect of said fibres and makes easier its holding.

[0062] As shown in Fig. 2, at each spinning position, the bundle 10 of effect fibres is added to the bundle 3 of base fibres through a condenser element 11 configured as a funnel that is placed between the first pair 2a of rollers and the second pair 2b of rollers.

[0063] This condenser element 11 includes a first inlet stretch 11a as a mouth that has a width enough to permit that each fragment of the bundle 10 of effect fibres and the bundle 3 of base fibres are joined on besides the other instead of one on the other, as in the state of the art. The same condenser element 11 includes a second outlet stretch 11b as a tunnel to merge or join each fragment of the bundle 10 of effect fibres with the bundle 3 of base fibres.

[0064] Another key element of the drafting train 1 of the claimed machine is the condenser element 12 configured as a floating wedge that is placed at the outlet of the drafting bag 9 of each spinning position.

[0065] In Fig. 4 is shown is detail the substantially flat shape of said condenser 12, which permit its placement between the second 2b and third 2c pair of rollers not changing the position of said rollers of the drafting bag 9 itself. This condenser 12 guarantees the cohesion of the fibres before the torsion, preventing the loss by aspiration of a great number of effect fibres.

[0066] Regarding the condenser 11 with a funnel shape, it is fixed on a banister 13 that can be horizontally moved when it receives the oscillating movement from an engine. This banister 13 is joined to the chassis of the machine, particularly to the bar 5 on which the pressure arms 6 are mounted, through a strip 14 (see Fig. 5).

[0067] As stated previously, the strip 14 has the advantage that, on one hand, prevents the vertical movement of the banister 13 and, on the other hand, acts as a spring permitting the horizontal movement of the banister 13 and prevents the overcharge of the engine through which said banister 13 is driven.

[0068] The horizontal movement of the banister 13, and with it the condenser 11, is necessary to prevent the premature wear of the upper rollers 2b, 2c produced by the passage of the fibres.

[0069] Regarding the condenser element 12 with a floating wedge shape, this is held by a rod 15 associated to the pressure arm 6 that holds the upper rollers 2a, 2b, 2c. This rod 15 can be horizontally moved on the arm 6 when the condenser 12 itself moves with the movement of the fibres produced by said banister 13.

[0070] As shown in detail in Fig. 4, the ends of the same rod 15 hold each one condenser 12, so that the same rod 15 can be used for two spinning positions.

[0071] Hereinafter an operation example of the method and the machine of the present invention are disclosed.

[0072] According to the kind of yarn to be produced, the processing and control unit is first programmed with the following input data:

• Basic draft ratio or number of times that the speed of the second pair of rollers 2b is lower than the speed of the third pair of rollers 2c for producing the drafting.
• Maximum and minimum separation length between additions of effect fibre.
• Length of the inj ected bundle 10 of effect fibres.
• Injection speed of the bundle 10 of effect fibres expressed as the ratio of the speed of the first pair 2a of rollers with respect to the second pair 2b of rollers.
• Backward movement length of the injected bundle 10 of effect fibres.
• Backward movement speed of the injected bundle 10 of fibres expressed as the ratio of the speed of the first pair 2a of rollers with respect to the second pair 2b of rollers.
• Slubby length that determines the acceleration time applied to the second pair 2a of rollers at the time that a fragment of the bundle 10 of effect fibres is added to the bundle 3 of base fibres in the drafting bag 9.
• Slubby thickness or number of times that the speed of the second pair 2b of rollers is increased with respect to the third pair 2c of rollers for producing the accumulation of slubby fibres (drafting reduction).

[0073] In the described example, the spinning of a fancy yarn made from a bundle 3 of white base fibres and a bundle 10 of blue effect fibres is pretended. In this specific case, the processing and control unit has been programmed to produce the fancy yarn as follows:

• Basic drafting ratio: 14.0, which is the number of times that the speed of the second pair of rollers 2b is lower than the speed of the third pair of rollers 2c to produce the drafting.
• Maximum separation length between additions: 850 mm
• Minimum separation length between additions: 1275 mm
• Length of the inj ected bundle 10 of effect fibre: 15 mm
• Injection speed of the bundle 10 of effect fibres: 1.20, which indicates the ratio of the speed of the first pair 2a of rollers with respect to the second pair 2b of rollers (in this case, 20% less velocity than the first pair 2a of rollers).
• Backward movement length of the injected bundle 10 of effect fibres: 5 mm.
• Backward movement speed of the injected bundle 10 of fibres: 0.40, which indicates the ratio of the speed of the first pair 2a of rollers with respect to the second pair 2b of rollers (in this case, 60% more speed than the first pair 2a of rollers).
• Slubby length: 20 mm.
• Slubby thickness: 3.00 or number of times that the speed of the second pair 2b of rollers is increased with respect to the speed of the third pair 2c of rollers to produce the accumulation of slubby fibres (drafting reduction).

[0074] The process is started, at each spinning position, in the moment that the first pair 2a of rollers is started driven by an independent servomotor for inj ecting an intermittent stretch of bundle 10 of effect fibres in the bundle 3 of base fibres that is being injected by the second pair 2b of rollers. This injection moment of the effect fibres is ordered by the processing and control unit through a "random" system that takes into account the maximum and minimum separation lengths between fibre additions to prevent the production of what is known as "moirée" or geometric repetition.

[0075] In the described example, the length of the injected bundle 10 of effect fibres is 15 mm and the injection speed of the bundle 10 of effect fibres (speed of the first pair 2a of rollers) is a 20% lower than the inj ection speed of the bundle 3 of base fibres (speed of the second pair 2b of rollers).

[0076] Once the programmed length of the bundle 10 of effect fibres has been injected, the first pair 2a of rollers is stopped and they begin the rotation in the opposite direction moving backwardly a stretch of the bundle 10 of effect fibres a preset length, said back movement permitting the cut or separation of a fragment to be added to the bundle 3 of base fibres in the drafting train 1.

[0077] In the disclosed example, the backward movement length of the stretch of effect fibres is 5 mm and the back movement speed of said stretch is a 60% higher than the injection speed of the bundle 3 of effect fibres (speed of the second pair 2b of rollers).

[0078] Once finished the inj ection of effect fibres, the fragment of the bundle 10 of effect fibres cut or separated is inserted inside the drafting bag 9 to be added to the bundle 3 of base fibres. In this moment, an acceleration of the injection speed of the base fibres is produced (speed of the second pair 2b of rollers) that produces an accumulation of fibres producing the slubby, matching the injection place of the fragment of effect fibres with said slubby.

[0079] In the disclosed example, the processing and control unit has been programmed to provide a slubby with a length of 20 mm and a preset thickness that is obtained increasing 3 times the injection speed of the base fibres 3 (speed of the rollers 2b of the second line) with respect to the speed of the rollers 2c of the third line.

[0080] As stated previously, it has been observed that the slubby makes easier the control of the length and thickness of the additions of the effect fibres, and improves the effect of said fibres.

[0081] Fig. 6 shows a view and a detail of a fancy yarn 16 obtained with the claimed method. In this yarn 16, the additions 16a of effect fibres match each with a slubby 17 of the base fibres 3. As shown in Fig. 6, thanks to the formation of the fragments and the slubby, the additions have a uniform and compact aspect providing the yarn a great quality.

[0082] Even though that a specific embodiment of the present invention has been described and shown, it is apparent that the person skilled in the art can introduce variations and modifications, or he/she can substitute the details by other technically equivalent ones, without departing from the scope of protection defined by the attached claims.

Claims

1. Method for spinning fancy yarns (16) comprising the steps of:

a) injecting continuously a bundle (3) of base fibres to a drafting train (1) of said bundle (3) of base fibres,

b) while said bundle (3) of base fibres is continuously injected, injecting intermittently a bundle (10) of effect fibres to said same drafting train (1) to add intermittently said bundle (10) of effect fibres to said bundle (3) of base fibres, characterised in that each intermittent injection of effect fibres of step b) includes the steps of:

bi) advancing a stretch of said bundle (10) of effect fibres to the drafting train (1) of said bundle (3) of base fibres, and

bii) then, moving backwardly said stretch a preset length, said backward movement permitting the forced cutting or separation of a fragment of bundle (10) of effect fibres to be added to the bundle (3) of base fibres in said drafting train (1).

2. Method according to claim 1, wherein, in step bii), the backward movement of said stretch of effect fibres is done at a speed higher than the injection speed of the bundle (3) of base fibres that are added to the effect fibres.

3. Method according to anyone of the previous claims, wherein, in said step bi), said bundle (10) of effect fibres is inserted in the drafting train (1) at a speed that is the same or lower than the injection speed of the bundle (3) of the base fibres.

4. Method according to anyone of the previous claims, wherein after each inj ection of step b) the following step is carried out:

c) acceleration of the injection speed of the bundle (3) of base fibres for producing a slubby (17) in said bundle (3) of base fibres, said acceleration being done at the moment which said fragment of bundle (10) of effect fibres is added to the base fibres, the injection place of said fragment matching with said slubby (17).

5. Method according to claim 4, wherein, in step c), said injection speed of the bundle (3) of base fibres a preset time according to the desired slubby length (17), and a present value according to the desired slubby (17) thickness.

6. Machine for spinning fancy yarns (16) comprising a fibre drafting train (1) provided, at each spinning position, with injection means (2b) of a bundle (3) of base fibres and injection means (2a) of a bundle (10) of effect fibres, said means (2a) for injecting effect fibres being associated to said means (2b) for injection base fibres, so that said bundle (10) of base fibres is susceptible of being added intermittently to said bundle (3) of base fibres in the same drafting train (1), characterized in that said means (2a) for injecting effect fibres are configured to permit the backward movement of a stretch of said bundle (10) of effect fibres when said means (2a) for injection effect fibres receives a backward movement signal from a processing and control unit of said machine that is configured to carry out the method according to anyone of claims 1-5, the backward movement of said stretch permitting the forced cutting or separation of a fragment of bundle (10) of effect fibres to be added to the bundle (3) of base fibres in the same drafting train (1).

7. Machine according to claim 6, wherein:

- said injection means of a bundle (10) of effect fibres includes, in each spinning position, at least a first pair (2a) of rollers between which said bundle (10) of effect fibres extends when said machine is operating, said rollers (2a) being able to rotate in both directions to permit the advancement or backward movement of said bundle (10) of fibres,

- said injection means of a bundle (3) of base fibres include, at each spinning position, at least a second pair (2b) of rollers between which said bundle (3) of base fibres extends when said machine is operating, said injection rollers (2b) of base fibres being placed according to the injection rollers (2a) of effect fibres to permit the intermittent addition of fragment of a bundle (10) of effect fibres to a bundle of base fibres passing by said second pair (2b) of rollers.

8. Machine according to claim 7, comprising belts (8) for drafting fibres associated with said second pair of rollers (2b), said belts (8) determining a bag (9) for drafting the fibres of said drafting train (1).

9. Spinning machine according to anyone of claims 6-8, wherein said drafting train (1) comprises, at each spinning position, a condenser element (11) configured as a funnel that is arranged between said means (2a) for injecting effect fibres and said means (2b) for injecting base fibres, said condenser (11) covering substantially the distance from the means (2a) for injecting effect fibres to the means (2b) for injecting base fibres to make easier the joining of said fragment of the bundle (10) of effect fibres with the bundle (3) of base fibres.

10. Spinning machine according to claim 9, wherein said condenser element (11) comprises a first inlet stretch (11a) as a mouth to join said fragment and said bundle (3) of fibres one besides the other, and a second outlet stretch (11b) as a tunnel to merge or join said fragment with said bundle (3) of base fibres.

11. Machine according to anyone of claims 9-10, wherein said drafting train (1) comprises, at each spinning position, support means of said condenser as a funnel, said support means comprising:

- a first support piece (13) on which said condenser (11) is fixed, said piece (13) being able to be moved laterally, and

- a second support piece of said support piece (13), said second piece including a support strip (14) that is joined to a chassis (5) of said machine, said strip (14) permitting the lateral movement of said first piece (13).

12. Machine according to anyone of claims 6-11, wherein said drafting train (1) comprises, at each spinning position, a condenser element (12) configured as a floating wedge, said floating condenser (12) being placed at the outlet of a drafting bag (9) associated with said means (2b) for inj ecting base fibres, permitting said condenser the cohesion of the assembly of effect fibres and base fibres before their torsion.

13. Machine according to claim 12, wherein said drafting train (1) comprises, at each spinning position, means for holding said condenser (12) as a floating wedge, said means including a support rod (15) that can be moved horizontally on a pressure arm (6) including rollers of said drafting train (1).

14. Fancy yarn (16) manufactured by the method according to anyone of claims 1-5, characterized in that it comprises a plurality of fragments of a bundle (10) of effect fibres added in a discontinuous way to a bundle (3) of base fibres.

15. Yarn according to claim 14, comprising a plurality of slubbies (17) of said bundle (3) of base fibres, each of said slubbies (17) including one of said fragments of a bundle (10) of effect fibres.

Drawing