METHOD FOR PRODUCING A CORE YARN

Description

[0001] The present invention relates to a method for producing a core yarn.

[0002] Core yarns consist of several components, with, for example, a filament forming the core of the finished yarn being wrapped with spinnable fibers. This combines the desired properties of the individual components. This allows for the production of elastic yet dimensionally stable fabrics that, for example, offer the comfort of cotton.

[0003] In the conventional production of core yarns, the filament enters a pair of clamping rollers via a deflection roller. These rollers clamp the filament, as well as a staple fiber bundle previously drawn in a drafting unit, along a clamping line. After leaving the clamping line, both components—the filament and the staple fiber bundle—are simultaneously gripped by a rotation initiated by a rotation control device. This device rotates around a yarn head, winding the yarn onto the head. German patent DE 198 04 341 A1 discloses such a device and a corresponding method. Because both the filament and the staple fiber bundle are gripped by the clamping line, the respective delivery speeds of the components relative to each other cannot be varied, and therefore, the final position of the filament within the yarn cannot be influenced.Thus, in conventional core yarns, the filament repeatedly reaches the surface of the finished yarn and is therefore partially covered by staple fiber composite along its length.

[0004] DE 10 2006 018 073 A1 and DE 198 15 054 C1 disclose ring spinning machines in which the core yarn is fed to the clamping line of an output roller pair by means of a feed roller having a groove, which engages the core yarn as well as a fiber assembly.

[0005] CN 102 787 410 and CN 102 787 412 show ring spinning machines for producing an effect yarn in which the core yarn is engaged at the clamping line of the output roller pair, while the staple fiber bundles laid around the core yarn run section by section into grooves formed on the circumferential surface of one of the output rollers and thus pass through the clamping line without being engaged by the output roller pair.

[0006] GB 765,295 discloses a ring spinning machine in which a roller of the output roller pair has a groove for receiving the core yarn, in which the core yarn can pass the clamping line without being engaged by the output roller pair, whereas the staple fiber bundles to be supplied to the core yarn are engaged by the output roller pair on both sides of the groove.

[0007] US 3009311 A and CN 102 330 235 A show further ring spinning machines for the production of a core yarn.

[0008] The object of the present invention is to provide a method for producing a core yarn whose core component is completely covered along its entire length by a staple fiber composite, thus preventing it from regularly protruding to the surface as in previous core yarns. Particularly when using one or more filaments as the yarn core, complete encasing of the yarn core by a staple fiber composite not only renders it completely invisible, which significantly improves the yarn's dyeability, but also prevents direct contact, for example, with the skin.

[0009] This problem is solved by a method according to claim 1.

[0010] The ring spinning machine, which utilizes the inventive method for producing a core yarn according to the present invention, comprises: a first material feed for a fiber composite made of staple fibers; at least one further material feed for at least one thread to be supplied to the fiber composite, in particular continuous filament; a drawing device for drawing the fiber composite; a clamping device with clamping rollers contacting each other in a clamping line, wherein the clamping device is passed through by the fiber composite leaving the drawing device and the at least one thread; a twisting device which twists the fiber composite leaving the clamping device and the at least one thread leaving the clamping device into a core yarn.

[0011] Compared to previous ring spinning machines for the production of core yarns, the ring spinning machine used in the inventive method is characterized by at least one groove circumferentially around the circumferential surface of at least one of the clamping rollers and interrupting the clamping line, which receives the at least one thread as it passes through the clamping device and guides it past the clamping line without it being clamped by the clamping rollers contacting each other.

[0012] According to the present invention, at least one thread, which will later form the core of the core yarn, is fed to the clamping device at the outlet of the drafting unit in a known manner and, like the staple fiber composite, runs between the two clamping rollers, which roll against each other along a clamping line. In contrast to previous solutions, however, this at least one thread is not clamped by the clamping rollers along the clamping line like the staple fiber composite, but is removed from clamping engagement by entering a groove, which is machined into the outer surface of at least one of the clamping rollers, before or at the latest at the clamping line. In this way, the at least one thread can pass the clamping line without coming into engagement with the clamping rollers.

[0013] It should be noted here that the at least one thread to be added to the fiber structure and forming the later yarn core can also comprise or consist of a staple fiber structure. Alternatively, the at least one thread can also comprise or consist of one or more continuous filaments. In particular, the at least one thread can comprise / be an inelastic continuous filament or an elastic continuous filament, whereby the at least one thread can specifically also comprise or consist of at least one inelastic continuous filament alongside at least one elastic continuous filament.

[0014] Furthermore, it is conceivable that several threads to be supplied to the fiber assembly are received by one and the same groove or by different grooves, which will be described in more detail later.

[0015] In addition to the at least one thread supplied according to the invention, at least one further thread can be supplied to the fiber composite in a conventional manner. Such a conventionally supplied thread can, for example, be an elastic or inelastic continuous filament which is engaged by the clamping rollers at the clamping line. In particular, such a conventionally supplied thread can be engaged in the section of the clamping line in which the staple fiber composite is also engaged by the clamping rollers.

[0016] In a special embodiment of the present invention, all components of the finished core yarn pass through the clamping device and / or are brought together before passing through a thread guide immediately adjoining the clamping device.

[0017] The first alternative is intended to express that no further components or parts are added to the core yarn after it leaves the clamping device, components which have not passed through the clamping device. The present invention specifically avoids the wrapping of the yarn leaving the drafting unit and the clamping device with a so-called effect yarn, as is common in so-called effect twisting machines, such as that shown in DE 24 12 390. Instead, all components of the subsequent core yarn are to be compactly combined and passed through the clamping device in order to be twisted into the finished core yarn immediately after the clamping line.Conversely, the finished core yarn may already be present at the end of the spinning triangle following the clamping line, although this does not preclude the core yarn from being twisted further before it is finally wound onto a yarn head.

[0018] According to the present invention, the finished core yarn can also be present in its composition before passing through the first thread guide, which in the transport process of the yarn connects directly to the clamping device or the clamping line without the interposition of any further equipment of the ring spinning machine.

[0019] According to one embodiment, the fiber assembly and at least one yarn can pass through a yarn guide immediately after leaving the clamping device. This yarn guide occupies essentially the same axial position relative to the rotational axis of one of the clamping rollers as a groove. This is intended to prevent the yarn components from being forced into a transport path by the yarn guide, causing the yarn, upon exiting the groove, to contact its walls and thus wear them down. A further advantage of this yarn guide arrangement is that it has minimal influence on the yarn twist caused by the rotation control device, allowing the twist to continue beyond the clamping line. This means the yarn can already be subject to rotational division before or even while passing the clamping line.

[0020] If several threads are to be guided through several grooves along the clamping line, this thread guide can be positioned relative to a preferred groove in the manner described above, while the other grooves, offset from it, can be arranged near the first-mentioned groove in order to minimize the influences described above.

[0021] As already indicated above, according to a further embodiment of the present invention, the clamping line can be interrupted multiple times by two or more grooves, which are spaced apart from one another and machined into the circumferential surface of one or more clamping rollers. The clamping line can also be interrupted at one or more points by two opposing grooves circumferentially around the circumferential surfaces of both clamping rollers. It should be noted here that pairs of clamping rollers are usually formed by a drive roller made of a metal material and a pressure roller made of a rubber material, which is pre-tensioned relative to the drive roller. The one or more grooves can be machined into one or both of these rollers in any desired manner.

[0022] Furthermore, it is conceivable that at least one or more grooves in cross-section have a flat or concave bottom area whose axial extent, parallel to the axis of rotation of the clamping roller, is at least the diameter of a thread to be received by the groove, and in particular at least twice the diameter. As already indicated above, it is advantageous that a thread received in a groove should, if possible, not contact the side wall of the groove to avoid unnecessary wear. To achieve this, the side walls of the groove can be sufficiently spaced apart. It would also be conceivable to center the thread in the groove by means of a suitable shape of the groove bottom to avoid contact with the side walls of the groove as much as possible. Here, it would be conceivable that the groove bottom is at least partially concave or has wedge-shaped converging sections.On the other hand, a clamping effect on the thread, similar to that of a V-belt pulley, should be avoided in order not to impair the thread itself or its transport.

[0023] To facilitate smooth thread entry into the groove before the clamping line, the groove can be designed such that its axial extent, parallel to the axis of rotation of the respective clamping roller, increases with increasing distance from the axis of rotation. In other words, the cross-section of the groove can widen towards the circumferential surface of the clamping roller, at least in sections. This could be achieved with a chamfered or rounded transition of the groove's sidewalls to the roller surface, or with groove sidewalls that diverge in cross-section.

[0024] According to another embodiment, at least one groove is spaced apart from the section of the clamping line in which the fiber bundle, after leaving the drawing unit, is clamped into engagement by the contacting clamping rollers. This prevents the groove provided for the yarn from becoming clogged with staple fibers that detach from the fiber bundle and thus becoming unusable for yarn guidance. On the other hand, a small distance between the groove and the section of the clamping line engaging the fiber bundle is desirable, since the necessary staple fiber length for processable fiber bundles decreases with a decreasing distance. Because the yarn leaving the groove is ultimately to be wrapped by the staple fiber bundle, the latter must be guided towards the yarn after it leaves the clamping line.The further the groove is spaced from the clamping line section engaging the staple fiber structure, the greater the distance the staple fiber structure must travel and, ultimately, the greater the risk of it tearing. According to the present invention, this distance can therefore be selected depending on the length of the staple fiber to be processed. It would be conceivable to vary the axial position of the groove by axially displacing the corresponding clamping roller in the ring spinning machine. Alternatively or additionally, the use of different clamping rollers with grooves arranged differently in the axial direction would also be conceivable.

[0025] Since the thread(s) guided by the at least one groove escape the clamping line and thus also the clamping engagement between the clamping rollers, they can be delivered in any way above or below the fiber core, i.e., they can exhibit an arbitrarily higher or lower delivery speed as they pass through the clamping device. Since, according to a preferred embodiment, complete coverage of the at least one thread by the staple fiber core along its entire length is desired, the thread can be delivered below the staple fiber core in such an embodiment. Because the fiber core exits the clamping device at a higher delivery speed in this case, it can wrap around the at least one thread and ultimately cover it completely.For example, the thread may have a delivery speed that is 5%, 10%, 15% or even 20% lower than the fiber bundle, meaning it may be delivered 5%, 10%, 15% or even 20% below the stated delivery speed.

[0026] It should be expressly emphasized at this point that the inventive method can include all the features described above and in connection with the ring spinning machine, individually and in any meaningful combination.

[0027] Another aspect disclosed herein, not belonging to the invention, relates to a core yarn produced by means of a ring spinning machine and / or a method as described above. Such a core yarn differs from previously known core yarns in that at least one thread is completely covered by the fiber structure along its entire length and thus does not reach the surface of the finished core yarn. In particular, the ring spinning machine and / or the method according to the invention can be configured to produce a core yarn as described above with a fineness of less than 1300 dtex, specifically less than 1000 dtex, and more preferably less than 580 dtex.The core yarn produced according to the invention can be used, for example, in the production of textiles, in particular clothing or upholstery fabrics for upholstered furniture or vehicle or aircraft interiors.

[0028] A preferred embodiment of the present invention is explained in more detail below with reference to the figures shown. The present invention can comprise the features contained therein individually or in any meaningful combination. The figures show: Figure 1: Illustration of a ring spinning machine used according to the present invention; Figure 2: Detail view of the clamping device of the ring spinning machine from the Figure 1 Figure 3: Side view of the clamping device from the Figure 2 .

[0029] The Figure 1Figure 1 shows a ring spinning machine used according to the present invention, by means of which a fiber assembly 2, also referred to as roving or spool, and a thread 4, provided in this case as an elastic or inelastic or rigid continuous filament, are drawn off from material stocks 1 and 3, respectively, and spun into a core yarn 11. The fiber assembly 2 drawn off from the material stock 1 passes through an infeed roller pair of the drafting unit 5 (not initially designated) and is then fed to the drafting unit 5, which pulls the staple fibers of the fiber assembly apart to a desired degree. Subsequently, the fiber assembly 2 is fed to an outfeed roller pair of the drafting unit 5, which is hereinafter referred to as the clamping device 6.The clamping roller 8, made of a metal material and designed as a drive roller, contacts the clamping roller 9, made of a rubber material and designed as a pressure roller, which is pre-tensioned opposite it, along a clamping line 7. The fiber assembly 2 is clamped along this line by the clamping rollers 8 and 9. Immediately after leaving the clamping line 7, the fiber assembly 2 is fed to the thread 4, which is drawn off from the material feed 3 by means of a drive device (not shown), guided over a deflecting roller (not shown), and passed between the clamping rollers 8 and 9 through the clamping device 6. In contrast to the fiber assembly 2, the thread 4 is not clamped by the clamping rollers 8 and 9, but is instead held in place by means of a groove (see the figure). Figure 2 and 3) is guided past the clamping line 7 and can therefore pass through the clamping device with a delivery relative to the fiber bundle 2. Even before the core yarn 11, consisting of the fiber bundle 2 and the thread 4 and already complete in its components, passes through the thread guide 14, the fiber bundle 2 delivered relative to the thread 4 is wrapped around the thread 4 by the twist distribution device 10 imposing a twist on both the fiber bundle 2 and the thread 4 before they are wound as a finished twisted core yarn 11 onto the unnamed yarn head.

[0030] The Figure 2 shows a detailed view of the clamping device 6 of the in the Figure 1The depicted ring spinning machine is shown along the rotation axes R of the clamping rollers 8, 9. It can be seen that the thread 4, taken from the material feed 3, is first guided over an unlabeled deflecting roller and, upon detaching from its circumferential surface, enters a groove 13, which is machined into the circumferential surface 12 of the clamping roller 9 and runs around its entire circumference. Since the depth of the groove 13 is greater than the diameter of the thread 4, the thread 4 is guided past the clamping line 7 in the groove 13 and consequently is not engaged by the clamping rollers 8, 9, as is the case for the fiber bundle 2. The latter is clamped between the circumferential surfaces 12 and 16 of the clamping rollers 9 and 8, respectively, along the clamping line 7.

[0031] The Figure 3 shows a side view of the AA viewing plane from the Figure 2It can be seen that the fiber assembly 2 and the thread 4 are guided between the clamping rollers 8 and 9, parallel and perpendicular to the axes of rotation R of the clamping rollers 8 and 9. The fiber assembly 2 is clamped by the clamping rollers 8 and 9 along section 15 of the clamping line 7. The thread 4 can pass along the clamping line 7 unhindered and unaffected by the rotation of the clamping rollers 8 and 9 by engaging in the groove 13, which is spaced apart from section 15 along the axis of rotation R of the clamping roller 9. Clogging of the groove 13 by staple fibers that detach from the fiber assembly 2 is effectively prevented by the distance of the groove 13 from section 15.

[0032] After passing the clamping line 7, the fiber bundle 2 is fed to the thread 4 and wraps around it in such a way that the thread is completely covered by the fiber bundle 2 along its entire length. This is achieved by supplying the thread 4 at a slightly lower rate than the fiber bundle 2, i.e., by having a lower delivery rate than the fiber bundle 2. Thus, the fiber bundle 2 has a sufficiently long delivery length to wrap around the thread 4. Furthermore, by placing the thread guide 14, which is immediately adjacent to the clamping line 7, in essentially the same axial position as the groove 13 (essentially "below" the groove 13), the thread 4 becomes the main point of application for the rotation, and the fiber bundle 2 therefore inevitably wraps around the thread 4.By positioning the groove 13 near the section 15 that clamps the fiber bundle 2, the fiber bundle 2 can be wrapped around the thread 4 without tearing, as staple fibers separate longitudinally. Even before the fiber bundle 2, together with the thread 4, passes through the thread guide 14, the finished core yarn 11, with all its components, is already present, just as it will ultimately be wound onto a yarn head. The twisting of the fiber bundle 2, together with the thread 4, caused by the twist distribution device 10 and beginning in the area of ​​the clamping line 7, continues even after passing through the thread guide 14.

Claims

1. Method for producing a core yarn (11) on a ring spinning machine, having: - a first material template (1) for a fibre composite (2) made of staple fibres; - at least one further material template (3) for at least one thread (4); - a drawing frame (5); - a clamping device (6) having clamping rollers (8, 9) in contact with one another in a clamping line (7), wherein at least one surrounding groove (13) that interrupts the clamping line (7) is formed on the peripheral surface (12) of at least one of the clamping rollers (8, 9); and - a rotation distribution device (10); wherein the method comprises the following steps: - providing the fibre composite (2) made of staple fibres; - providing the at least one thread (4) to be fed to the fibre composite (2); - drawing the fibre composite (2) in the drawing frame (5); - feeding the fibre composite (2) leaving the drawing frame (5) and the at least one thread (4) through a clamping device (6); - twisting the fibre composite (2) leaving the clamping device (6) and the at least one thread (4) leaving the clamping device (6) by the rotation distribution device (10) into a core yarn (11), wherein the thread (4) is wrapped by the fibre composite (2); - guiding the at least one thread (4) past the clamping line (7) by the groove (13) receiving said at least one thread as it runs through the clamping device (6) without said at least one thread being engaged via clamping by the clamping rollers (8, 9) in contact with one another, characterised in that the spacing of the at least one groove (13) from the portion (15) of the clamping line (7) in which the fibre composite (2) leaving the drawing frame (6) is engaged via clamping by the clamping rollers (8, 9) in contact with one another, is selected in the axial direction along the axes of rotation (R) of the clamping rollers (8, 9) and according to the length of the staple fibres of the fibre composite (2).

2. Method according to claim 1, wherein all components of the finished core yarn (11) run through the clamping device (6) and / or are combined before running through a thread guide (14) directly connected to the clamping device (6).

3. Method according to claim 1 or 2, wherein the fibre composite (2) and the at least one thread (4) run through a thread guide (14) immediately after leaving the clamping device (6), said thread guide occupying substantially the same axial position in relation to an axis of rotation (R) of one of the clamping rollers (8, 9) as a groove (13).

4. Method according to one of claims 1 to 3, wherein the clamping line (7) is interrupted by two surrounding grooves (13) located opposite each other on the peripheral surfaces (12, 16) of the respective clamping rollers (10, 11), and / or the clamping line (7) is interrupted several times by two or more grooves (13) that are axially spaced apart from one another.

5. Method according to one of claims 1 to 4, wherein the at least one groove (13) has a flat or concave bottom region in cross-section, the axial extension of said bottom region along the axis of rotation (R) of the clamping roller (8, 9) equalling at least the diameter, in particular at least double the diameter of a thread (4) received by the groove (13).

6. Method according to claim 1 or 5, wherein the axial extension of at least one groove (13) increases with increasing radial spacing from the axis of rotation (R) of the respective clamping roller (8, 9).

7. Method according to one of claims 1 to 6, wherein at least one thread (4) to be fed to the fibre composite (2) and received by a groove (13) is under-delivered in relation to the fibre composite (2).