The invention relates to a device for producing fancy yarns, such as yarns with variable effects. Embodiments described herein relate in particular to multiple yarns, i.e., composite yarns composed of more than one initial yarn for example a core yarn and an effect yarn. The invention also relates to a method for producing fancy yarns, in particular fancy multiple yarns.
To produced slub yarns, i.e., effect yarns or fancy yarns, devices are known, which introduce a variation in tension in the yarn while it advances along a process path. For this purpose, in some devices a pick-up element, having a movement transverse to the yarn path, is provided along the processing yarn path. The pick-up element grips the yarn and moves it transversely, lengthening the path thereof, before releasing it suddenly. Devices of this type are disclosed in EP 0453622, EP0829444, U.S. Pat. No. 6,820,405, WO 2009/033697 and EP 3246438.
U.S. Pat. No. 3,999,361 discloses a method and a device for producing multiple yarns. The device comprises a system for imparting a false twist on the yarns. The system consists of a pair of rollers with parallel and counter-rotating axes, which define a nip therebetween. The yarn is made to pass through the nip with a trajectory parallel to the axes. To impart an intermittent false twist on the yarn, it is inserted cyclically into the nip and moved away from it by means of a guide provided with a reciprocating motion. The reciprocating motion of the guide is orthogonal to the plane containing the rotation axes of the two rollers.
GB 2214528 discloses a system for producing a fancy yarn, wherein a pair of yarns is fed to a twisting device. Of said two yarns, one forms the core and the other the external decorative thread of the fancy yarn that is formed by combining the two yarns. To obtain this effect, the two yarns are fed through a nip formed between two overfeed rollers. One of the two rollers is shaped, and has a central area of smaller diameter. By means of a guide comb the two yarns fed to the nip between the two overfeed rollers it is possible for one of the two yarns to be pinched between the two rollers and over-fed due to the peripheral speed of the rollers, while the other yarn remains in the area of smaller diameter of the shaped roller, so as to be fed at a lower speed. The yarn fed at lower speed forms the core of the fancy yarn obtained by combining the two yarns.
According to a first aspect, a device for generating variable effects on a yarn is provided, comprising a first roller rotatable about a first rotation axis and a second roller rotatable about a second rotation axis, approximately parallel to the first rotation axis. The first roller and the second roller are in mutual contact and define a yarn passage therebetween. At least one of the rollers is motorized. Moreover, the device has at least a first guide member defining a feed path for at least one yarn. The guide member is associated with the first roller and with the second roller and is adapted to guide at least a yarn through the passage defined between the first roller and the second roller. Moreover, the guide member and the two rollers are provided with a mutual, i.e., relative, movement in a direction substantially parallel to the first rotation axis and to the second rotation axis. With the translation movement the yarn can be taken periodically and temporarily outside the contact area between the first roller and the second roller, so as to temporarily interrupt the effect of the rollers on the yarn.
The term periodically, as used herein, must not necessarily be intended in the sense that the movement follows a periodic law of motion, with repetition at regular intervals of time of the translation motion. On the contrary, the translation movement of the yarn outside the mutual contact area between the rollers can also occur in a completely random manner. What is important is that the loss of contact between yarn and rollers is temporary, i.e., occurs for specific periods of time. In practice, the yarn is alternately pinched between the two rollers and free, outside the mutual contact area between the rollers.
By taking the yarn outside the mutual contact area between the rollers, and thus removing the effect of the rollers on the yarn, said yarn can, for example, undergo a temporary variation in tension, which forms slubs or similar effects on the yarn.
Although it is possible to carry out the mutual movement between rollers and guide member maintaining the latter fixed with respect to a supporting structure and moving the rollers parallel to their rotation axes, for simpler construction it is preferable to maintain the rollers with their axes fixed with respect to a supporting structure and to move the guide member with respect to the supporting structure and to the rollers.
The movement of the guide member can be controlled by any suitable actuator, for example through an electronically controlled actuator, which can be controlled by a programmable unit. In this way, it is possible, for example, to set a series of parameters such as the dwell time of the yarn path outside and inside the passage between the rollers in the mutual contact area therebetween. Moreover, it is possible, for example, to program the frequency of the translation movement of the guide member with respect to the rollers.
Preferably, for better control of the yarn, the device can comprise a second guide member movable in synchronism with the first guide member. To obtain a structure that is simpler and more easily controllable, the first guide member and the second guide member can be integral with a single supporting element, movable with respect to the pair of rollers. Advantageously, the first guide member and the second guide member can be positioned one upstream and the other downstream of the mutual contact area between the two rollers.
In some embodiments, one or both the rollers can have beveled edges to facilitate re-introduction of the yarn into the mutual contact area between the rollers.
In some embodiments, the device can be adapted so that the yarn exits on only one side of the pair of rollers, but it would also be possible for the yarn path to be modified by the guide member or members, so that it exits from the nip, i.e., from the mutual contact area between the two rollers, both on one side and on the other. However, as the effect that is obtained on the yarn is due to the temporary loss of contact with the two rollers, and this effect is independent of the fact that the yarn exits from the nip, i.e. mutual contact area, between the rollers on one side rather than the other, to reduce the travel required between the guide member or guide members and the rollers, in some cases it is preferable for the yarn path to be taken outside the contact area between the rollers always on the same side.
According to a further aspect, a machine for producing a fancy yarn is provided, comprising a feed path of at least a yarn from at least a feed spool to a winding bobbin, wherein along said feed path there is arranged at least a yarn processing member and at least a device as described above.
The machine can, for example, be an air texturizing machine, or a false twist texturizing machine, or a combined air and false twist texturizing machine.
The machine can be a shaft machine, i.e., a machine with several machining positions controlled by common control shafts that extend for the whole of the machine front. In other embodiments the machine can be a machine with individual positions.
According to a further aspect, a method for producing a fancy yarn is provided, comprising the steps of:
feeding at least a yarn along a feed path between a first rotating roller and a second rotating roller, in mutual contact and defining a yarn passage therebetween, wherein the two rollers are in mutual contact; and while the yarn advances along the feed path, temporarily moving the feed path outside the yarn passage between the first roller and the second roller and returning the feed path inside the yarn passage between the first roller and the second roller.
Further features and embodiments of a device according to the invention, of a machine that uses this device and of a method for treating yarns according to the invention are described hereunder and defined in the appended claims.
In the sense used herein, the term yarn designates in general a substantially linear, i.e., substantially one-dimensional, textile article of indefinite length. Preferably, the yarns are continuous yarns, i.e., formed of one or preferably several continuous filaments, in particular obtained by polymer extrusion.
The invention will be better understood by following the description and accompanying drawings, which show a non-limiting exemplary embodiment of the invention. More in particular, in the drawing:
With initial reference to
With initial reference to
One of the two rollers 3, 5 can be coated with a material with high coefficient of friction, such as natural rubber, synthetic rubber, or the like. In the embodiment shown, the roller 5 is coated with a coating 5R made of a material with high coefficient of friction, so that the mutual contact between the rollers 3, 5 allows motion to be transmitted from the roller 3 to the roller 5.
The two rollers 3, 5 are in mutual contact and form therebetween a yarn passage 7, which is pinched between the rollers 3, 5 in the mutual contact area between them. In the present context, the area between the rollers 3, 5 where they are in mutual contact, and in which the yarn passage is defined, is also called nip 7. A feed path of yarns F1, F2, F3, F4 is indicated with Pa. In some operating conditions of the device 1 the feed path Pa passes through the nip 7, i.e., through the yarn passage 7 defined in the contact area between the rollers 3, 5, as shown in
F1, F2, F3, F4 can pass outside the nip 7, i.e., outside the mutual contact area between the rollers 3, 5. While the embodiment of
The device 1 further comprises a first guide member 9, with a head 11 forming one or more guide elements for one or more yarns F1-F4. In the example shown, the guide member 9 comprises a head 11 that forms four guide elements for the four yarns.
In some embodiments, the device 1 comprises a second guide member 13, with a head 15 forming one or more guide elements for the yarns F1-F4. In preferred embodiments, the first guide member 9 and the second guide member 13 are substantially identical to one another. In some embodiments, the two guide members 9, 13 can be mechanically connected to one another; for example, they can be connected to a same support 17.
The heads 11 and 15 can have ceramic bodies that define one or more guide grooves for the yarns. In the example illustrated the heads 11 and 15 each have four guide grooves.
The two guide members 9, 13 are positioned one upstream and the other downstream of the nip 7, or contact area between the rollers 3, 5, with respect to the direction of advance of the yarns F1-F4 along the feed path Pa. Said direction of advance is indicated by arrow fF. The heads 11, 15 of the two guide members 9, 13 can be arranged so that the portion of the feed path Pa of the yarns F1-F4, defined between the two heads 11, 15 is approximately orthogonal to a plane containing the two rotation axes 3A, 5A of the two rollers 3, 5.
The two guide members 9, 13 and the related heads 11, 15 are provided with a reciprocating translation motion according to the double arrow f9 with respect to the rollers 3, 5. The movement is clearly visible comparing
In the view of
The motion according to f9 is a reciprocating motion that can be controlled electronically, for example so that it is periodic, with a simple or complex law of motion, or random, for the purposes that will apparent from the description below. Therefore, the yarns F1-F4 are repeatedly taken from the position between the rollers 3, 5 (
Due to the fact that the two guide members 11, 13 are fixed to a common support 17, the reciprocating translation movement according to f9 can be imparted on the two guide members 11, 13 by a same actuator, not shown. For example, the translation movement can be imparted by an electronically controlled electric motor, in combination with a mechanical transmission that converts the rotational motion of the electric motor into a translational motion of the support 17.
Operation of the device described above is as follows. The rollers 3, 5 can belong to a drawing assembly, arranged along a yarn feed path in a complex machine, for example a texturizing machine. Exemplary embodiments of these machines will be described below with reference to
A first simplified layout of a texturizing machine, in which a device 1 of the type illustrated in
Operation of the machine 20 as a whole, without the device 1, is known (see, for example U.S. Pat. No. 6,820,405). The addition of the device 1 allows a sudden modification of the draw of the yarn F along the feed path Pa1, taking the yarn F rapidly inside and outside the mutual contact area 7 between the rollers 3, 5 of the device 1 in the manner described above. This causes the formation of fancy effects in the yarn.
In a modified embodiment, as illustrated in
The feed paths Pa1, Pa2 converge into a common feed path Pa in which an air texturizing jet 42 is located and where the two yarns Fa and Fe are combined to form a composite yarn Fc. The feed path Pa ends with a take-up assembly B of the yarn on a bobbin. A master godet 44 that sets the speed of the machine is arranged upstream of the take-up assembly B.
The device 1 allows the tension in the yarn Fe, and consequently its degree of draw, to be modified rapidly and repeatedly, generating variable effects on the yarn upstream of the interlacing jet 42.
More in particular,
Pa of the yarns F coming from the spools R positioned on the creel 52. A false twist assembly 58 is positioned downstream of the cooling plate 56. The briefly described machine 50 is per se known.
A device 1 of the type illustrated in
It must be understood that the diagrams of
Moreover, it must be understood that the device 1 can be used in single or multiple machines, for example in machines as illustrated in
Number | Date | Country | Kind |
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102018000005854 | May 2018 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2019/063245 | 5/22/2019 | WO | 00 |