JPS6219532B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a frictional false-twisting method and apparatus, and more particularly to an improvement in a belt-type false-twisting method in which yarn is introduced and passed between frictional engagement surfaces formed by bringing a pair of endless belts into cross-contact with each other. Conventionally, there are spindle methods, internal friction methods, and external friction methods for twisting yarns, but all of these methods have various problems and limitations as the speed increases, and they are not suitable for high-speed processing. Even with the friction type, it is said that machining speeds of 1000 m/min are the limit. The reason for this is that in the internal or external friction type, the yarn is simply run in contact with the inner or outer surface of the rotating body, so during high-speed processing, the yarn stays slip occurs frequently and the stability of twisting is affected. One example of this is a significant decrease in On the other hand, as another example of the frictional false twisting method, a pair of endless belts are brought into cross-contact, and yarn is introduced between the contact surfaces (hereinafter referred to as "between the frictional engagement surfaces") to impart false twisting. There is. In this method, compared to the above-mentioned internal or external friction method, twisting is performed by sandwiching the yarn between belts, so a stable false-twisting operation is expected. In particular, the machining speed exceeds the previous limit of 1000m/min, and is currently exceeding 1500m/min.
When the speed reaches 2000 m/min, the belt type false twisting method described above can be said to be extremely promising. However, when the inventors conducted additional tests on this belt type, they were able to obtain a more stable twisting effect than the conventional internal or external friction type at a processing speed of about 1000 m/min, but at processing speeds of 1500 m/min to 2000 m/min. At higher speeds, a significant states-slip phenomenon was observed. In order to prevent the deterioration in twisting efficiency due to the occurrence of staple slip, the inventors of the present invention have previously discovered that it is useful to provide a plurality of consecutive contact and engagement surfaces by belts. This method has made it possible to obtain extremely superior twisting properties compared to the case where there is only one contact engagement surface, but on the other hand, there is a problem separate from the twisting properties, which is the drawback that some yarn breakage occurs. It turns out that there is. The purpose of the present invention is to provide a belt-type false twisting method and device that eliminates the staple slip phenomenon as described above and provides a stable twisting effect without fear of yarn breakage even under ultra-high speed processing of 2000 m/min. It is about providing. As a result of intensive research aimed at achieving the above object, the inventors of the present invention found that excessive centrifugal force and vibration occur randomly on belts running at high speed. Although it is useful to provide a surface, it was found that this caused some slack in the yarn between the first contact friction surface and the second contact friction surface, which caused yarn breakage. . Thus, according to the present invention, (1) a pair of endless belt parts configured to run suspended between a driving pulley and a driven pulley are brought into cross-contact with each other; In forming more frictional engagement surfaces and applying false twist by continuously introducing and passing yarn between the engagement surfaces,
A friction false twisting method characterized by increasing the belt speed sequentially along the running direction of the yarn, and (2) a structure in which two or more endless belts are suspended and run between a driving pulley and a driven pulley. In a false twisting device, a pair of endless belt parts are brought into cross-contact with each other to form two or more frictional engagement surfaces, and the yarn is continuously introduced and passed between the engagement surfaces. There is provided a friction false twisting device characterized by having a drive pulley whose diameter increases successively along the running direction of the yarn. To further describe this, the present invention aims to stabilize yarn running in a system that employs a plurality of frictional engagement surfaces, and in particular two frictional engagement surfaces forming the first contact surface (engagement surface). Belt speed of one set of two belts forming the second contact surface than V ₁ of one set of belts
By making V ₂ faster, the tension of the thread between the first and second contact surfaces is increased to prevent the thread from sagging. The present invention will be explained in detail below with reference to the accompanying drawings. FIG. 1 is a partial perspective view of a belt-type friction false twisting device according to a prior application by the present inventors, and FIG.
It is an X′ cross-sectional view. In the figure, an endless belt 1a
and 1a are suspended by a drive pulley 3 and a driven pulley 4, and when the drive pulley 3 is driven by a drive motor 7, the belts 1a, 1a are suspended by a drive pulley 3 and a driven pulley 4.
b travels in the directions of arrows a and b, respectively. Similarly, the endless belts 2a and 2b are also suspended between a pulley 5 and a driven pulley 6 driven by a drive motor 8.
They travel in the directions of arrows a' and b', respectively. By bringing these two sets of running endless belts into cross-contact with each other, a contact surface c between belts 1a and 2a and a contact surface d between belts 1b and 2b are formed. However, when the thread e is continuously passed through such contact surfaces c and d, the thread e is attached to the belts 1a, 2a and 1b, 2.
At the same time as the wire is sandwiched between the wires b and twisted, a feeding force is applied to the wire, and a so-called false twisting process is performed. At this time, yarn e becomes slack between contact surfaces c and d, making running unstable. The reason for this is related to the fact that the belt applies twisting force and feeding force to the yarn, and will be explained here with reference to FIG. In FIG. 3, V _B1 and V _B2 represent the belt speeds of belts 2a and 2b, respectively. When the thread e crosses the belt at an angle θ/2, the belt gives the thread e velocity components V _T1 , V T2 in the twisting direction, V _T2 , and velocity components V _D1 , V _D2 in the feeding direction, respectively. The magnitudes are expressed as V _T1 =V _B1 ·sinθ/2, V _T2 =V _B2 ·sinθ/2, V _D1 =V _B1 ·cosθ/2, and V _D2 =V _B2 ·cosθ/2, respectively. Now, here, belt speeds V _B1 and V _B2 of 2a and 2b
are equal, so V _D1 =V _D2 . However, in general, a certain tension is required to transport the thread.
To generate such tension, the downstream velocity must be faster than the upstream velocity.
In other words, when V _D1 =V _D2 , there is no tension and the running becomes unstable. Therefore, in the present invention, in order to eliminate the disadvantages of providing a plurality of frictional engagement surfaces, V _D2 >V _D1 is set, and the second contact surface d is given the function of transporting the yarn e. Here V _D2
Regarding the relationship between speed and V _D1 , an excessively large difference between the two will have the opposite effect, so it is generally appropriate to select V _D2 within the range of 1.005V _D1 to 1.05V _D1 . be. Next, the pulley structure for obtaining the speed difference as described above will be described with reference to FIGS. 4 and 5.
Here, FIG. 4 is a plan view of one endless belt portion used in the present invention, and FIG. 5 is a cut side view taken along the line Y--Y' in FIG. In the figure, the driving pulley 3' has the shape of a stepped roller, and the pulley 3' as a whole is fixed to the output shaft 12 of the motor 7, and is held and driven by a bearing of the motor. Similarly, the driven pulley 4', corresponding to the pulley 3', is in the form of a stepped roller, but is held by bearings 9 and 10 mounted on the fixed shaft 11. A belt 1a is suspended between the small diameter portions of the drive pulley 3' and the driven pulley 4', and a belt 1b is suspended between the large diameter portions. On the other hand, the thread e advances as shown by the arrow, so
In the embodiment shown in Fig. 5, V _B1 , V
The speed will increase in the order of _B2 . 6 and 7 show more preferable embodiments of the present invention, FIG. 6 is a plan view of one belt portion, and FIG.
The figure is a cutaway side view taken along line Y-Y' in FIG. 6. In this example as well, the drive pulley 3' is fixed to the output shaft 12 of the motor 7, and is held and driven by the bearing of the motor 7. On the other hand, the driven pulley is divided into two parts, 4'' and 4, held by bearings 9' and 10' built into the fixed shaft 11, respectively, and driven by belts 1b and 1a.
The feature of this method is that when the two belts 1a and 1b are suspended between the driving pulley and the driven pulley,
This is because each belt is disposed between the large diameter portion and the small diameter portion. Here, if the radius of the part where the pulley 3' suspends the belt 1a is r ₁ and the radius of the part where the belt 1b is suspended is r ₂ (r ₁ < r ₂ ), then the speed V _B1 of the belt 1a and the speed V B1 of the belt 1b. Between _B2 and V _B1 <V
The relationship _B2 holds true. Therefore, V _D1 <V _D2 , the tension necessary for running the yarn is generated, and the running is stabilized.
The reason why the driven pulley is divided into 4" and 4 parts so that they can rotate independently is as follows. In other words, the driven pulley is divided into 4" and 4 parts as shown in Figures 4 and 5. If _{the pulley} is
The relationship between r ₃ and the radius r ₄ of the suspension part of the belt 2a is r ₄ /r ₃ =
The relationship r ₂ /r ₁ =V ₂ /V ₁ holds true. Moreover, this relationship is required to be strictly established. If this relationship does not hold, the belt and pulley will slip somewhere, which may cause problems in terms of belt life. Furthermore, since the outer circumferential lengths of the belts 1a and 1b are also different, it is necessary to prepare two types. In this regard, in FIGS. 6 and 7, the radius r ₄ of the pulley 4 on which the inner belt 1a of the driven pulley is suspended is
is equal to the large diameter r ₂ of the drive pulley 3', and the radius r ₃ of the pulley 4'' is equal to the small diameter r ₁ of the drive pulley 3'. With this arrangement, the first contact surface c and the second The contact surfaces d are lined up without any difference in level as shown in Fig. 7, and the yarn e runs quickly without bending between the contact surfaces that come down.Therefore, the yarn travel is stabilized and the false twisting effect is good. , the fatigue of the belt will be reduced.Now, in this way, the diameter of the driven pulley is set to 4.
If 4'' is equal to r ₂ and 4'' is equal to r ₁ , then the rotational speeds N ₁ and N ₂ of 4 and 4'' will be different, and V _B1 = N ₁ r ₄
= Nr ₁ , V _B2 = N ₂ r ₃ = Nr ₂ (N is the rotation speed of pulley 3' r ₁ = r ₃ , r ₂ = r ₄ ) In the end, N ₁ /N ₂ =
(r ₁ /r ₂ ) ² . Since N ₁ and N ₂ are different, it is necessary to rotate each pulley 4'' independently, so the pulley 4'' is held and rotated by a bearing 9', and the pulley 4 is held by a bearing 10'. As an example of the present invention, when partially oriented polyester yarn was false-twisted using the apparatus shown in FIGS. 6 and 7, the number of yarn breaks was as shown in Table 1. Processing conditions (1) False twisting method Simultaneous stretching and false twisting (IN-DRAW) (2) Raw yarn used Polyethylene terephthalate partially oriented yarn 225de/30filament (3) Processing speed 1500m/min (4) Stretching ratio 1.5x (5) Belt contact condition Tension side Comrade (6) Pulley speed increase ratio 0, 0.5, 1, 2, 3,
5, 7, 10% (7) Equipment used Figure 6, 7 Results

[Table] From the table above, it can be seen that when the speed is increased by 0.5 to 5%, yarn running becomes stable and yarn breakage decreases. As described above, according to the present invention, a belt-type false twisting method is provided which is free from concerns about staple slip and yarn breakage.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the basic structure of the belt-type false twisting device employed in the present invention, and Figure 2 is
FIG. 3 is an explanatory diagram of the twisting force and feeding action of the yarn by the belt; FIGS. 4-5 and 6-7 are explanatory diagrams of the pulley portion used in the present invention (plane Figure and side view). 1a, 1b, 2a, 2b...Endless belt, 3,
3', 5... Drive pulley, 4, 4', 4'', 4
, 6... Driven pulley, 7, 8... Motor,
c, d...adjacent frictional engagement surfaces, e...yarn, V
_B1 , V _B2 ... Belt speed, r ₁ ... Small diameter part of stepped drive pulley 3', r ₂ ... Large diameter part of stepped drive pulley 3', r ₃ ... Small diameter part of driven pulley 4', _r4 ...
Large diameter part of driven pulley 4'.

Claims (1)

[Scope of Claims] 1. By bringing a pair of endless belt portions configured such that two or more endless belts are suspended between a driving pulley and a driven pulley into cross-contact with each other, two or more points can be A frictional engagement surface is formed, and when the yarn is continuously introduced and passed between the engagement surfaces to impart false twist, the belt speed is sequentially increased along the running direction of the yarn. Friction false twisting method. 2. The friction false twisting method according to claim 1, wherein the belt speed is increased sequentially by 0.5 to 5% between adjacent belts along the yarn running direction. 3 Two or more endless belts are configured to run suspended between a driving pulley and a driven pulley, and two or more frictional engagement surfaces are formed by bringing a pair of endless belt parts into cross-contact with each other. A false twisting device configured to continuously introduce and pass the yarn between the engaging surfaces is characterized in that a drive pulley whose diameter increases successively along the running direction of the yarn is provided. Friction false twisting device. 4 The diameter of the large diameter part is 0.5 to 0.5% larger than that of the small diameter part.
Claim 3 with a 5% larger pulley
Friction false-twisting device as described in .