JPS5812941B2 - false twisting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the processing of synthetic fiber yarns, and more particularly to a false twisting device for crimping.

A false twisting spindle is currently widely used as a false twisting device.

However, the practical upper limit of the processing speed by the spindle is usually 100 m/mm to 150 m/mm in terms of yarn traveling speed, and if the speed is higher than this, troubles such as generation of a large amount of fuzz and yarn breakage occur.

In addition, in the spindle method, the drawing tension must be greater than the tension in the twisting area, but as the drawing tension increases, the generation of fuzz increases rapidly. A friction false twisting device has been proposed.

As one type of conventional friction false twisting device, a device is known in which yarn is passed through so as to come into contact with a friction rotating body having a surface with a large coefficient of friction, and the yarn is rubbed by the friction rotating body.

Such a surface friction false twisting device can achieve a high processing speed compared to a spindle.

However, as the processing speed increased, yarn breakage increased, and there was a tendency for the operability to decrease and fuzz to increase.In particular, in the false twisting of polyester filaments, the occurrence of fuzz and a decrease in strength were remarkable.

In addition, in the frictional false-twisting method, twisting is normally done by the frictional force between the yarn and a high-friction body, so it is difficult to twist the yarn using a spindle-based false-twisting method, which requires a certain amount of tension for twisting. Compared to the case where the yarn is wrapped once around the pin to ensure false twisting, the twisting efficiency is poor, and snack slips tend to occur between the yarn and the high friction body, resulting in unresolved twisting. This will make it easier for twisting to occur.

At the same time, the tension on the untwisting side also increases as the processing speed (travel speed of the yarn) increases, which causes problems with productivity and quality, such as the generation of fuzz and the induction of yarn breakage, so it is difficult to find a practical processing speed. The limit is about 500 to 600 meters per minute.

Furthermore, the number of twists was estimated by measuring the actual number of twists by grasping the thread while it was running, or by referring to the pre-determined correlation between the actual number of twists and the twisting tension. , it is difficult to accurately manage the number of twists.

As a different type of conventional false-twisting device, two rotating disks with an annular convex portion on their circumferences are brought into contact with each other with their central axes offset, and the yarn is passed through the contact portion to perform the false-twisting process. It is a device.

However, in such a device, a relatively large contact pressure is required between the discs in order to reliably knead the thread between the discs.
The surface of the convex portion of the disk was easily worn, making stable false twisting difficult.

In order to prevent such wear, it has been considered to pass fiber bundles between a pair of narrowly spaced belts, but it is difficult to nip thin yarns and stable false twisting cannot be achieved.

Therefore, the main object of the present invention is to provide a false twisting device that can perform false twisting at high speed.

Another object of the present invention is to provide a false twisting device which nips yarn and simultaneously imparts twisting and unwinding effects.

Still another object of the present invention is to provide a false-twisting device that can stably perform false-twisting over a long period of time.

The friction false twisting device according to the invention has at least two endless belts with a relatively small coefficient of surface friction, both belts running intersectingly at an angle and their surfaces touching each other at the intersection. arranged so that the yarn is passed between the contact surfaces of both belts through an angular region between the directions of travel of both belts, whereby the yarn is nipped between both belts,
As both belts run, they are twisted and simultaneously subjected to a feeding action.

The present invention will be described with reference to FIG. 1. A false twisting device 1 includes flat endless belts 2 and 3 made of synthetic rubber, for example, which are arranged to cross each other at an angle of θ. 2 and 3 are supported by pulleys 4 and 5 and 6 and 7, respectively, and are driven by drive pulleys 8 and 9 in the direction of the arrow.

As shown in FIG. 2, both endless belts 2 and 3 travel at the same speed in different directions while being in planar contact at the intersection.

The yarn 10 is heated by a heater (not shown) upstream of the false twisting device 1, passes through the entrance side guide 11, and then passes through the endless belt 2,
3 through the area of angle θ between the traveling directions of contact intersecting plane 1
2, where it is nipped by both belts 2 and 3, false-twisted, sent out, and taken out via the exit side guide 13.

As shown in FIG. 1, the traveling directions of the endless belts 2 and 3 form an angle smaller than 90° with respect to the traveling direction of the yarn 10, so the belts 2 and 3 not only twist the yarn 10, but also twist the yarn 10. It also provides a pull action to the yarn 10.

That is, if the running speed of the belt 20 is V1 and the angle between the belt 20 and the thread 10 is θ1, then the feed speed V2 given to the thread 10 by the belt 2 is V2=V1 cos θ1.

The same applies to the belt 3. As will be described later, the false twisting device 1 can be configured to be able to change the angle between the yarn 10 and the belts 2 and 3, and by changing this angle to a desired value,
The feeding speed of the yarn 10 can also be changed to a desired value.

Here, it is most preferable to adjust the angles θ1 and θ2 between the belts 2 and 3 and the yarn 10 so that θ1=θ2 from the viewpoint of yarn feeding stability.

Figure 3 shows the surface speed Vn (m/mm) of the belts 2 and 30 and the yarn feeding speed V2 (m/mm) inevitably generated by the belt.
mm) is shown for the angle between the belt and the thread.

In this way, the yarn 10 produced by the false twisting method according to the present invention is produced by the belt 2.
, 3 apply a feeding action in the nipped state, so that the feeding speed V2 is made to match the processing speed V determined by the upstream supply roller and the downstream take-up roller of the false twisting device 1.

That is, if the adjustment is made so that V2=V, the yarn 10 can be false-twisted without any difficulty, and ultra-high speed processing, for example, false-twisting at a yarn speed of 800 to 1000 m/mm, may damage the yarn. It became possible without any problems.

In addition, since the false twisting method of the present invention twists the threads while nipping them, unlike the conventional friction false twisting method that uses contact friction, in which the number of false twists cannot be accurately determined, the number of false twists can be calculated as follows. It can be predicted accurately from a theoretical formula such as

That is, in the false twisting device of the present invention shown in FIG.
The surface speed of the twisting belts 2 and 3 is V1, the delivery speed from the false twisting device is V2, and the twisting speed acting in the horizontal direction due to the running of the twisting belts 2 and 3 is V3. The angle is θ, the angle between the thread 10 and each belt 2, 3 is θ1, θ
2 as θ1=θ2=θ/2, the following relationship holds true.

Also, the cross-sectional area of the thread in the denier method is πr2 = de x 10-8-6/0.9 x ρ (cm2) where de: denier r: radius of thread ρ: specific gravity, so rearrange this formula. Then, further expressing this in diameter, depending on the running of the twisting belt, the number of rotations of the yarn itself when the yarn is rotated, Yr. P. m. is expressed by the following formula.

Therefore, the number of twists per 1 m is expressed as N, and the number of false twists changes by changing the angle θ of the twisting belt.

To try to find the number of false twists for each material, refer to Table 1 below.

Below, as an example of the number of false twists determined from Table 1, the number of false twists per meter for polyester fibers is shown in Table 2, and the graph showing the change in the number of false twists N of 50 denier polyester fibers is shown below. It will look like Figure 4.

As described above, the false twisting device according to the present invention allows the number of false twists to be managed accurately as in the spindle method.

In the false twisting method of the present invention, in which two twisting members are brought into contact with each other and the threads are nipped and proceed in different directions,
Wear of the twisting members becomes a problem.

Wear greatly depends on the contact pressure between the twisted members and the wear coefficient.

When the present inventor uses an endless belt as a twisting member, the surface of the endless belt has flexibility that can be displaced to some extent in a direction perpendicular to the surface, and exhibits elasticity against a force perpendicular to the surface. Therefore, it is relatively small, for example less than 300g, and even 1
It has been found that a sufficient nip effect can be obtained even at a contact pressure of 0.00 g or less.

Furthermore, in conventional frictional false twisting devices, twisting members with a large surface friction coefficient were generally used in order to enhance the twisting effect, but the present inventor found that conversely, it is preferable to use a twisting member with a relatively small surface friction coefficient. .

In other words, if a high friction material is used on the surface of the twisted belt, heat will be generated as the belt moves, and the surface will become excessively sticky, causing the belt to not move smoothly and risk coming off the pulleys.

From this point of view, it is preferable that the friction coefficient μ between the surfaces of the false twisted belt used in the present invention is μ<0.5,
It has been found that it is particularly preferable that 0.1<μ<0.4, and more preferably 0.2<μ<0.3.

FIG. 5 is an explanatory diagram of the support mechanism 20 that supports the twisted belt shown in FIG. 1, and the support mechanism for the twisted belt 2 and the twisted belt 3 shown in FIG. ,
In FIG. 5, only the support mechanism 20 for the twisted belt 2 is shown.

The rotation shaft of the pulley 4 is supported by a bearing 22 provided on a support base 21, and the rotation shaft of the pulley 5 is supported by a bearing 23 provided on the support base 21.

This bearing 23 is movably provided on the upper surface of the support base 21 so that the tension of the twisting belt 2 can be adjusted.

The support stand 21 has an arc-shaped guide hole 25 centered on the center 24 of the intersecting surface 12, and the fixed frame 26 has a bolt 2.
7 is implanted, the tip of which passes through the guide hole 25 gently,
A nut 28 is screwed together.

Further, the support stand 21 has a pointer 29, and the fixed frame 26
has a scale 30 corresponding to the pointer 29.

That is, by tightening the nut 28 to the bolt 27, the support body 21 is maintained fixed to the fixed frame 26, but when the nut 28 is loosened, the support base 21 is moved within the range of the guide hole 25 with respect to the fixed frame 26. Therefore, when it becomes necessary to change or adjust the introduction angle θ2 of the yarn 1, for example, when it is necessary to reduce θ2, loosen the Nantes 28 and move the center 24 of the intersecting plane 12. Rotate the support base 21 clockwise, and when the pointer 29 comes to a predetermined position by looking at the dial 30, firmly tighten the nut 28 on the bolt 27 at that position to fix the support base 21 to the frame. It may be fixed to 26.

In FIG. 5, a part of this state is shown by a chain double-dashed line.

Furthermore, if it becomes necessary to increase θ2, the support base 21 may be rotated counterclockwise in the same manner as described above.

According to the false twisting device of the present invention, since the yarn is nipped between the twisting belts 2 and 3, the false twisting tension T1 (tension upstream from the nip point) and the untwisting tension T2 (tension downstream from the nip point) niT
Not only 1<T2, but also T1=T2 and T1>T2.

That is, in the conventional false-twisting method, the yarn is pulled by a thread winding roll or the like and sent out from the false-twisting device, so that T1<T2.

However, in the false twisting method of the present invention, the belt applies a feeding action to the yarn, so by selecting the processing speed V (yarn feeding speed) as shown in FIG. 6, the relationship between T1 and T2 can be adjusted over a wide range. It can be changed.

In other words, Figure 6 shows the false twisting tension T1 (grams) and untwisting when the speed V2 of the feeding action inevitably generated by the twisting belt is kept constant at V2 = 750 m/mm and the processing speed V is changed. It shows the relationship of tension T2.

In this way, the magnitude of the untwisting tension and the false-twisting tension can be changed from positive to opposite, which has the effect of providing variety in the appearance of the false-twisted yarn, and even at ultra-high speeds. The operability is extremely good, and even in the processing of polyester, no fuzz is observed at all, and the effect is extremely large.

Next, specific examples according to the present invention are as follows.

The materials used are polyester, acrylic, and nylon as representative synthetic fibers, and acetate, which has the lowest strength, was selected.

When each fiber is processed under the conditions shown in the table below, a crimped yarn with a cohesive appearance can be easily obtained, and compared to conventional crimped yarns, it has a spun-like appearance, but can be processed at high speed and almost The effect obtained without fluff was confirmed.

As is clear from the above examples, in order to suppress the occurrence of fuzz, it is preferable that T2/T1<2.0, particularly preferably T2/T1≦1.0, and more preferably 0.
It is preferable that 005≦T2/T1≦1.0.

As described above, according to the false twisting device according to the present invention, a feeding action can be applied to the yarn at the same time as the false twisting while the yarn is nipped between the belts. Twisting processing becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of an apparatus according to the invention. FIG. 2 is an enlarged sectional view taken along line 1--2 in FIG. FIG. 3 is a graph showing the relationship between the running speed V1 of the twisting belt and the feeding effect V2 exerted on the yarn. FIG. 4 is a graph showing the relationship between the angle θ between the twisted belts and the number N of false twists. FIG. 5 is a diagram showing an example of a support structure for the twisted belt shown in FIG. 1. FIG. 6 is a graph showing the relationship between yarn supply speed V and yarn tension. Explanation of symbols, 1... False twisting device, 2, 3...
... Endless belt, 4, 5, 6, 7... Pulley,
8, 9... Drive pulley, 10... Yarn.

Claims (1)

[Claims] 1 a first endless belt provided on a first support base;
a second endless belt provided on a second support base and arranged so that its surfaces intersect with the first endless belt and come into contact with each other at the intersection; and the first and second endless belts. and a mechanism for rotating the first support base around the intersection of the belts, passing the thread through the intersecting plane of the first and second endless belts, thereby This is a false twisting device in which the yarn is nipped between both belts and is twisted as the belts advance and at the same time receives a feeding action.