KR19990087402A - Reduced thread breaks in yarn spinning or twisting processes - Google Patents

Abstract

The present invention relates to a method and apparatus for twisting a moving fiber assembly (7) to form a twisted yarn (9), wherein the strand is pulled from the nip means (14) and rotated to twist the yarn. Downstream of the nip, the surface (s) of the belt means rotate the yarn and pull the nip into engagement with and at least one run 34 or 35 of the moving continuous belt means 30 and past the run. To false twist. The surface (s) are convexly curved in the direction of movement of the yarn, and the yarn (s) across the curved line contact portion sufficient to substantially reduce the tension transfer of the yarn past the surface (s) towards the nip. ) Is engaged.

Description

Reduced thread breaks in yarn spinning or twisting processes

It is known that thread breaking, which occurs mainly in the spinning zone between the front drafting roller and the yarn guide during ring spinning, depends on the tension and twist level of the yarn. It is known that the transfer of tension caused by the spindle and balloon is partially reduced by the yarn guide, but the degree of twist tends to decrease in the direction from the guide to the nip of the front draft roller. have. In addition, the degree of twist in the tetragonal region also tends to vary locally. Other related factors are the cross sectional area of the yarn and the number of fibers in the cross sectional area, which also vary along the yarn. Thread breakage occurs when the combination of yarn twist, cross-sectional area and fiber density falls below the threshold associated with the tension present in the yarn.

Thus, what has been proposed so far to reduce the occurrence of thread breakage, together with improving the balance of twisting tension in the tetragonal region, increases the degree of twisting on the yarn guide, or reduces the tension transfer towards the front draft roller. Focus has been on. One of the many proposals is a rotary yarn guide that increases the amount of twist in the region by false twisting the yarn in the square region between the guide and the front draft roller. One of these suggestions is W. W. Kampen, published in Melliand Textilber (English version), 60, 433, June 1979, the yarn guide includes a friction tube driven by magnetic coupling with the spindle. . Others are disclosed in "Threading in Ring Squares" by TA Subramanian et al, published by Ahmedabad Textile Industry's Research Association (ATIRA), wherein the tube is rotated by the yarn itself. . In another case, a separate mechanical driver is provided.

Wilkie U.S. Patent No. 4,384,448 proposes to provide a pneumatic false twister between the guide and the front draft roller. Another form of mechanical combustor provided at the point is H.M. Reports titled "Clemson Dean proposes New Technique" reported in HM Brown, US Patent Nos. 2,590,374, 2,718,111 and 1949 Textile Bulletin, Found in the May 1954 issue of Textile Industries, page 96, "Reducing Thread Break". These combustors are primarily discs of various orientations and shapes, but US Pat. No. 2,590,374 includes embodiments (tansversely acting belt run) directly adjacent to the guide (FIGS. 7 and 8).

Such rotary yarn guides are useful for increasing the degree of twist and in some cases are effective for effectively reducing the transmission of tension, but are difficult to thread and require a separate mechanism for each spindle, It requires capital costs.

Another approach to reducing the spindle tension is to deform the upper spindle, known as the spindle crown. This approach has been reviewed by Textile-Proxis (International), Schenkel on page 150 (1963), and generally by balloon with a yarn wrap device. Partial or complete collapsing of. Spindle crowns have not achieved significant commercial use due to cost and complexity.

A somewhat different approach is to have the fibers bind more closely to each other using hydraulic compression to increase the strength of the yarn while forming the yarn by spinning, without or with a spinning triangle. . Such a system is described in Meridian International (1995), 1: 30-34, Betz, D, "Innovation of the Ring Square Sector."

FIELD OF THE INVENTION The present invention generally relates to spinning or twisting yarns, and is not particularly limited, but specifically includes end breaks during ring spinning. It's about the problem.

1 is a schematic perspective view showing the operating state of a single spindle section of a ring spinning machine modified to provide an embodiment of the device according to the invention.

2 is a corresponding schematic cross-sectional view.

3 is a reference diagram for applying the law of amonton.

It is an object of the present invention to reduce the occurrence of thread breaks, effectively and in a cost saving manner, at least when applied to a ring square.

The present invention is based on the recognition that while the transverse actuated belts disclosed in FIGS. 7 and 8 of U. S. Patent No. 2,590, 374 described above have potential uses as combustors herein, it is advantageous to further modify them. In particular, the angular contact between the yarn and the belt surface described in this patent is very small and reflects a small angular deviation of the yarn path by the belt. In one aspect of the invention, the reduction in thread breakage is increased by burning into the square region, thereby substantially further reducing the propagation of the tension into the square region, which means that the propagation of the tension becomes smaller as the angular contact becomes larger. This can be achieved using the theory and the Capstan Theory and Amonton's law.

The arrangement shown in FIGS. 7 and 9 of US Pat. No. 2,590,374 has other disadvantages. In order to avoid excessive lateral fluctuation of the yarn path by the transversely moving belt surface, the belt must be positioned very close to the yarn guide. In a second aspect of the invention, the yarn is arranged to engage two runs of the continuous belt means, thereby avoiding this limitation and balancing with sideways drag.

Thus, in a first aspect of the present invention, there is provided a method of twisting a yarn by twisting and rotating the strand from the nip means to form a twisted yarn and twisting the traveling fiber assembly. Providing a twisted yarn downstream of the nip to engage at least one run of the moving continuous belt means and past the run so that the surface (s) of the belt means rotate and twist the yarn toward the nip. Wherein the surface (s) are convexly curved in the direction of movement of the yarns and the yarns are full of curved line contacts sufficient to substantially reduce the tension transfer of the yarns towards the nip past the surface (s). Engage with said surface (s) over.

In addition, in a first aspect of the present invention, there is provided an apparatus for twisting a moving fiber assembly to form a twisted yarn, comprising: delivery means including an exit nip; Rotatable twist means for pulling and twisting a fiber assembly from said nip to form a twisted yarn; A continuous belt means moving in use, the belt means being arranged to form a pair of runs, at least one of which is engaged by the twisted yarns as the twisted yarns are pulled, (S) rotate the yarns to combust the yarns towards the nip, the surface (s) are convexly curved in the direction of yarn movement, and the belt means, upon operation of the device, the yarns cross the surface (s) It is arranged to engage the surface (s) throughout the curved line contact sufficient to substantially reduce the tension transfer of the yarn towards the nip.

In a second aspect of the present invention, there is also provided a method of twisting a yarn by twisting and rotating the strand from the nip means to form a twisted yarn, and twisting the moving fiber aggregate, the twist downstream of the nip. Pull the yarns into engagement with the two running runs opposite the moving continuous belt means such that the surface (s) of the belt means rotate and twist the yarns toward the nip, the lateral drag of each run on the yarns being substantially Is offset.

The present invention also provides a device for twisting a moving fiber assembly to form a twisted yarn, comprising: a delivery means comprising an exit nip; Rotatable twist means for pulling and twisting a fiber assembly from said nip to form a twisted yarn; A continuous belt means that moves when in use, the belt means being arranged to form a pair of runs, the pair of runs being engaged by the twisted yarns as the twisted yarns are pulled, thereby providing a surface of the belt means ( S) rotate the yarn to combust the yarn towards the nip, and the lateral drag of each run on the yarn is substantially offset in operation.

The twisted yarn is preferably pulled to engage two runs of the belt means moving in the opposite direction and past these two runs, through the back of one of the runs and through the front of the other run.

The device is preferably a square device, in which the delivery means comprise draft means, the twisting means being a spindle that can be rotated to wind and twist the yarn.

Preferably, the continuous belt means are arranged such that each engaged run moves transversely relative to the direction in which the yarn is pulled by the spindle, eg at a substantially 90 ° angle to the direction.

The fiber aggregate is preferably a staple fiber aggregate, in particular wool roving / strand.

Typically, a spinning device includes a yarn guide, such as a pigtail, between the spindle and the nip, a ring and a traveler system that winds the yarn onto the spindle.

The continuous belt means is preferably arranged between the yarn guide and the nip.

Preferably, in a spinning frame with a plurality of spindles, a single moving belt is arranged to engage a plurality of yarns.

It is preferred that means be provided which are able to adjust the movement of the belt means and / or its orientation and contact properties with the yarn (s).

The invention is described in detail below, with reference only to the embodiments, with reference to the accompanying drawings.

The depicted square section includes a prior art transfer or draft portion 12 that includes a double apron 11 and a front draft roller 13 forming an exit nip 14. The take up spindle 16 has a ring 19 and a traveler 18. Pigtail yarn guide 20 is typically located between the nip and the spindle. In operation, the roving 7 is drafted by the draft portion 12 and the rotating spindle pulls the draft strand 8 from the nip 14 and winds it onto the spindle 16 as a yarn 9, while itself The yarn is twisted by the rotation. This twisted yarn returns to the nip 14 in a tapered and locally varying state. Of course, the yarn has increased tension due to the yarn balloon 9 generated by the centrifugal force between the ring 19 and the yarn guide 20.

A false twist belt unit 25 is disposed between the nip 14 and the yarn guide 20. This unit generally comprises a continuous belt 30 of circular cross section and a suitable elastic material exhibiting adequate surface friction. The belt 30 is mounted around each drive and idler pulley 32, 33 forming an orientation plane, which is the nip 14 of the front draft roller 15. Intersecting the yarn travel diameter path from the yarn guide 20 to the yarn guide 20 at an angle, the upper run 34 of the belt 30 is disposed in front of the straight line of yarn movement, and the lower run 35 is disposed behind the straight line. In this arrangement, and due to the circular cross section of the belt, the belt surface is convexly curved in this direction and in the yarn moving surface.

The deformed square section is threaded up, so that the yarn is pulled around the front of the upper belt run 34 and the rear of the lower belt run 35, thus allowing the two curved lines to contact the belt. Once the spindle and belt are now in operation (mechanical drive is not described in detail), the surfaces of each belt run engaged with the moving yarn move transversely with the yarn, at a substantially 90 ° angle, thus rotating the yarn. Twist the yarn towards the nip 14. The twist of the yarn formed by the two belt runs accumulates above the upper run 34. This increases the degree of twist of the yarn in the square region 31 on the belt 30 without substantially affecting the average degree of twist of the yarn wound onto the spindle. In addition, the linear contact of each belt run with the yarn is effective to reduce the transfer of tension to the square region. The increased degree of twist and reduced tension both contribute to substantially reducing the occurrence of line breaks in the square region 31 on the belt.

The decrease in tension is considered to be a reflection of Amonton's law and capstan theory, which occurs when the slippage of the cable around the capstan or post occurs when the tension ratio (T ₁ / T ₂ ) exceeds the exponential function of μθ. Μ is the coefficient of friction between the cable and the capstone surface, and θ is the subtended angle in the contact circular axis. Another expression of capstan theory is that around a capstan or free standing post, relatively small forces can be balanced with larger forces at very large angles of the wrap.

Referring to Amonton's Law and FIG. 3 with respect to the flammable belt correction arrangement, the yarn tension depends on the angle of the wrap as follows.

T ₂ / T ₁ = e ^{μθ One} & T ₃ / T ₂ = e ^{μθ 2}

In combination,

T ₃ / T ₁ = e ^{μ (θ One + θ 2 )}

As the angle of the wrap θ ₁ + θ ₂ increases, the value of T ₃ / T ₁ also increases (ie, the difference between T ₁ and T ₃ also increases). Therefore, the larger the angle of the wrap, the greater the decrease in tension into the square region. This prediction is supported by observation.

The curved contact is sufficient to substantially reduce the tension transfer through the unit 25. The substantial decrease is at least 30%. In the experiment producing 25 tex wool yarns with a draft of 14.5 at a spindle speed of 10,000 rpm, the yarn tension in the control test without unit 25 was 20 cN. To the unit 25 in position adjusted to obtain an angular deflection in the yarn path of 2 × 33 °, 56 ° + 47 °, 77 ° + 62 ° (and therefore at the lap of the angle) in both belt runs Yarn tensions measured were about 9 cN, 10 cN, and 3 cN, respectively. As is evident from the above formula, the decrease in tension depends on μ and thus also on the yarn and belt material.

It should be noted that the twist belt unit 25 is sufficiently returned so as not to interfere with doping.

According to the principles of the first aspect of the present invention, a useful degree of twisting and tension reduction is possible by contacting only one belt run, which is more simple when threaded than the device shown, but engages with two runs. It is useful in three ways. Tension reduction at both contacts is added, and there is also an increase in combustibility. Since each run moves in the opposite direction, it cancels the side drag in the yarn, thus canceling the tendency of the moving yarn to move laterally. Some constrains for lateral yarn movement are required when configured to make contact only in one place, but such constrains may also be required in the case of double run contact while threading. In some cases it may be advantageous to use two or more belt runs to engage two or more.

A particular economical attraction of the device shown is the use of a single continuous belt for a plurality of yarns on a square frame, compared to conventional flammable or tension reducing devices that require separate devices for each spindle. Guide pulleys or other stabilizers may of course be required at intervals along long belt runs.

It will be appreciated that the false belt unit 25 may have a number of optional or advantageous features. For example, provision may be made to change the speed of movement of the belt 30, or to make the operation intermittently, for example, on-off or front-rear, in order to obtain a particular tetragonal effect. For example, intermittently actuating the belt 30 using a stepper motor in order to intermittently twist transfer may result in strand twist on two folds of yarn, such as a Sirospun (tradename) yarn. It will be useful when adding. Of course, in general the invention can be applied to fold spinning, twist or fold operation.

The angle of the belt 30 plane with respect to the straight line of travel between the front draft roller and the yarn guide can be adjusted to control the contact angle of the belt and the yarn, thus controlling the tension transfer of the yarn. For example, tension adjustment may be used to compensate for tension changes during the cycle of yarn package from the spindle. The balance between decreasing tension and increasing degree of twist can also be controlled by changing the cross-sectional diameter or surface friction of the belt 30. The spacing between the belt runs can be adjusted using, for example, an adjustable idler.

In a particular embodiment, a flammable belt may be used for yarn surface treatment, such as through the addition of waxes, moisture, lubricants or dyes.

If desired for a particular purpose of reducing the amount of twist and tension of the upper yarns, it may be effective to reverse the direction of the belt.

If the lower belt run can be moved to allow doping, another option is to place the lower belt run vertically over the pigtail in order to maximize twist transfer from the pigtail upstream. This moving line 8 ′ for the yarn is indicated by the dashed line in FIG. 2.

Another effective variant is to orient the yarn path such that the yarn path is tangential or nearly tangential to the nip at the front draft roller, so that the twist can propagate to the yarn and reduce the occurrence of line breaks near the nip. Deformation of the yarn path is facilitated by the unit 25. In Figure 1 it can be seen that the yarn is lifted closer to the tangential position. Positions closer to the tangential can be achieved by adjusting the position and placement of the unit 25.

The present invention relates to short and long stapling squares of yarns at worst spinning, or more generally to wool spinning or quasi-consuming spinning, especially when folding into two folds, particularly short and long staple syrup spoon processes, a simple It will be appreciated that it can be widely applied to ring twist operation.

In general, the ability provided by the present invention to reduce the relative occurrence of thread breaks results in a higher spindle speed for a given yarn break rate, or square yarns at lower twists at a given yarn break rate. To be possible. Optionally, the yarn break rate can be reduced for a given yarn count and degree of twist. According to the present invention, it is possible to square a poor quality fiber material at a given yarn count, spindle speed, and degree of twisting, and to successfully yarn a yarn with a low fiber count per cross-sectional area into an acceptable yarn product.

By the embodiment shown and the present invention, a yarn with a more uniform distribution of twist along the yarn can be obtained by causing a change in the degree of twist and tension in the yarn forming region (ie, the front draft roller). This has the advantage of reducing the streakiness of the yarns and fibers, and has the advantage of reducing the cockling or the stitch distortion of the knitted fabrics made of folded yarns. have.

As anticipated in the previous report, the smaller the square region, the less fiber shedding and the less hairy yarn.

It is understood that the term "comprise" or grammatical variations thereof herein is equivalent to the term "include" and does not mean that the term does not exclude the presence of other elements and features. will be.

Claims (26)

A method of twisting a yarn by pulling and rotating strands from the nip means to form a twisted yarn, and twisting the traveling fiber assembly, Downwards of the nip, the twisted yarn is pulled into engagement with and past the one or more runs of the moving continuous belt means such that the surface (s) of the belt means rotate the yarn and combust toward the nip. (假 撚, false twist) The surface (s) are convexly curved in the direction of movement of the yarns, and the yarns pass through the surface (s) and the surface (s) throughout the curved line contact sufficient to substantially reduce the tension transfer of the yarn towards the nip. )). 2. The twisted yarn of claim 1 wherein the twisted yarn is pulled into engagement with and past the two runs moving in the opposite direction of the belt means, through the back of one of the runs and through the front of the other run. Characterized in that. 3. The method of claim 1 or 2, wherein the fiber aggregate is a strand and comprises spinning the strand to form a twisted yarn that is wound over a spindle that rotates to twist the yarn. 4. A method according to any one of the preceding claims, wherein the continuous belt means is substantially circular in cross section. 5. The method according to claim 1, wherein the fiber aggregate is a staple fiber aggregate, preferably wool. 6. An apparatus for twisting a moving fiber assembly to form a twisted yarn, Delivery means including an exit nip; Rotatable twist means for pulling and twisting a fiber assembly from said nip to form a twisted yarn; A continuous belt means that moves when in use and includes belt means arranged to form a pair of runs, At least one of the runs engages the twisted yarn as the twisted yarn is pulled such that the surface (s) of the belt means rotate the yarn and burn it towards the nip, The surface (s) are convexly curved in the direction of yarn movement and the belt means is curved enough to substantially reduce the tension transfer of the yarns across the surface (s) towards the nip upon operation of the device. And engage with said surface (s) throughout a line contact. 7. The belt of claim 6 wherein the belt means are arranged such that two runs of the belt moving in opposite directions intersect the yarn path, the yarn passing through the back of one of the runs and through the front of the other run. Device. 8. A device according to claim 6 or 7, wherein the device is a square device, wherein the delivery means comprises a draft means and the twist means is a spindle rotatable to wind and twist the yarn. 10. The apparatus of claim 8, further comprising a ring and traveler system winding a yarn guide between the spindle and the nip and a yarn wound on the spindle. 10. The device of claim 9, wherein the continuous belt means is disposed between the yarn guide and the nip. 10. The device according to any one of claims 6 to 9, wherein the continuous belt means is substantially circular in cross section. 12. The continuous belt means according to any one of claims 6 to 11, wherein the continuous belt means moves the interlocked run transversely with respect to the direction in which the yarn is pulled by the spindle, for example in a substantially 90 ° angle direction with the direction. Device, characterized in that the arrangement. The device according to claim 6, wherein the spinning frame has a plurality of spindles and the belt means is a single moving belt arranged to engage a plurality of yarns. . 14. An apparatus according to any one of claims 6 to 13, further comprising means for adjusting the movement of the belt means and / or its orientation and contact properties with the yarn (s). A method of twisting a yarn by twisting and rotating the strand from the nip means to form a twisted yarn, and twisting the moving fiber assembly, Downwards of the nip, the twisted yarn is engaged to engage and run past the run, which is opposite the moving continuous belt means, so that the surface (s) of the belt means rotate the yarn and twist the yarn towards the nip. (Iv, false tywist), wherein the sideways drag of each run on the yarn is substantially canceled out. 16. The method of claim 15, wherein the twisted yarn is pulled at the back of one of the runs and at the front of the other run. 17. The method of claim 15 or 16, wherein the fiber aggregate is a strand and comprises spinning the strand to form a twisted yarn that is wound onto a spindle that rotates to twist the yarn. 18. The method according to any one of claims 15 to 17, wherein the continuous belt means is substantially circular in cross section. An apparatus for twisting a moving fiber assembly to form a twisted yarn, Delivery means including an exit nip; Rotatable twist means for pulling and twisting a fiber assembly from said nip to form a twisted yarn; A continuous belt means that moves when in use and includes belt means arranged to form a pair of runs, At least one of the runs engages the twisted yarn as the twisted yarn is pulled so that the surface (s) of the belt means rotate the yarn and burn it towards the nip, and in operation the side of each run on the yarn. Directional drag is substantially offset. 20. The apparatus of claim 19, wherein the yarn is arranged to be pulled at the back of one of the runs and in front of the other run. 21. A device according to claim 19 or 20, wherein the device is a square device, wherein the delivery means comprises a draft means, the twisting means being a spindle rotatable to wind and twist the yarn. 22. The apparatus of claim 21, further comprising a ring and traveler system for winding a yarn guide between the spindle and the nip and a yarn on the spindle. 23. The device according to claim 22, wherein the continuous belt means is disposed between the yarn guide and the nip. 24. The interlocking belt according to any of claims 19 to 23, wherein the continuous belt means moves the interlocked run transversely with respect to the direction in which the yarn is pulled by the spindle, for example in a substantially 90 ° angle direction with the direction. Device, characterized in that the arrangement. 25. An apparatus as claimed in any of claims 19 to 24, wherein the spinning frame has a plurality of spindles, and the belt means is a single moving belt arranged to engage a plurality of yarns. . 26. The device according to any one of claims 19 to 25, further comprising means for adjusting the movement of the belt means and / or its orientation and contact properties with the yarn (s).