JPS6350450B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a friction false twisting machine comprising two rotating discs which sandwich yarn with their mutually opposite end faces (German patent application no.
2928522 specification). One of the discs is made of a flexible material that absorbs high tensile forces but only low bending forces. A pressing device is installed on the back side of this flexible disc,
This pressing device bulges and/or deflects the flexible disk out of a plane perpendicular to the axis of rotation in a predetermined desired range. Both discs therefore contact and tighten the thread only in a narrowly defined area. In a friction false twister of the type mentioned at the outset, the other surface can also be constructed as a flexible disc of the type described above with a pressing device. However, it is equally possible for the other surface to be a rigid, ie bendingly rigid, disc or roller.

A particular advantage of a friction false twister of the type described above is that it not only twists the yarn, but also transports the yarn. This is because the circumferential speed of the disc of the friction false twister crosses the yarn axis in the crimping range.
This is because it has a twist component and a transport component.

The object of the invention is to improve a friction false-twisting machine of the type mentioned at the outset in order to create a friction false-twisting machine in which all parameters effective for the twist formation and the texturing effect can be optimally adjusted independently of each other. The goal is to provide opportunities.

In order to solve this problem, in the configuration of the present invention,
The distance between the axes of both disks is variable and/or the distance between the pressing device and a plane passing through each axis of both disks is variable along the thread running direction. By adjusting these two distances or one of the distances, an optimum state can be obtained regarding the direction of the circumferential speed of the disk having the conveying component and the twisting component and the yarn running direction.

A further special advantage is that the pressure device acting on the rear side of the flexible disc defines a pressure range of small size, which allows the components of movement of the two discs to be adjusted correspondingly precisely in this pressure range. One example is that it can be defined.

The motion component and its direction can be specified most easily by changing only the distance between the pressing device and the axial plane common to the axes of both discs without changing the distance between the axes of both discs. .

This already ensures that all operating conditions required for a given range of use are adjusted. If a wider range of operating conditions is desired, the distance between the axes of both disks may be changed. If the distance between the axes of the disks and the distance between the pressing device and an axial plane common to the axes of both disks are variable, the entire operating range of the friction false twister can be utilized optimally.

By varying the distance between the axes and/or by varying the distance between the pressing device and an axial plane common to the axes of both discs,
It is advantageous if the pressing device forms the apex of an isosceles triangle and the axes of the two disks form the end points of the base of this isosceles triangle. As a result, the front disk and the rear disk can apply mirror-symmetric motion components to the yarn.

It is advantageous if the base angle of the isosceles triangle formed by the pressing device and the two axes lies in the range from 50° to 65°.

By adjusting the distance between the axes and/or the distance between the pressing device and the axial plane common to the axes of both discs, the conveying component and the twisting component, which are the resolved components of the disc peripheral speed at the twisting point, can be adjusted. The ratio can be defined at the twisting location, that is, the pressing range.
In this case, the component of the circumferential velocity of the disk that extends in the direction of the yarn axis is the conveyance component, and the component that extends perpendicularly to the yarn axis is the twist component. By appropriate adjustment of the distance between the axes and the pressing device, the twisting points are arranged in such a way that the base angle of the isosceles triangle formed by the two axes and the pressing device is equal to the twist angle of the false twisted yarn. is advantageously selected.

It should be noted in this case that the twisting causes geometrical changes in the yarn, mainly due to an increase in diameter and a decrease in length. There is therefore a considerable difference between the twist angle of the yarn in the twisted state and the twist angle obtained purely by calculation based on the yarn length and yarn diameter in the untwisted state.

The above-mentioned advantageous adjustment of the friction false twister provides the first prerequisite for obtaining a good twisting effect.

In a friction false twisting machine consisting of three shafts rotating in the same direction and disks inserted into these shafts and overlapping between the shafts, the angle between the disk rotation direction and the yarn running direction is It has already been proposed to select the interaxial distance and/or the axial arrangement of the discs so that they are equal to the angle (DE-A-2310803). This is said to enable slip-free operation. However, this known friction false twisting machine does not take into account the fact that a sufficient normal force must be generated between the surface of the friction disk and the yarn in order to entrain the yarn without slipping. . Developing said normal force is a requirement, which is not achieved in this known friction false twister.

In contrast, in the present invention, in order to carry out the texturing process optimally and to optimally impart twist to the yarn, especially in a friction false twisting machine of the type mentioned at the outset, all advantageous parameters, including slip, are utilized. The requirements for individual independent adjustment are provided.

What must be noted here is that slip-free operation is not always desired. In other words, in order to release the false twist and to adjust the yarn tension, it is absolutely desired that a certain amount of slip occur.

However, in a further embodiment of the invention for slip-free operation which is desired in many cases, the pressing force of the pressing device is determined by the normal force exerted on the yarn by the disc, the coefficient of friction and the yarn radius. is adjusted such that the twisting moment consisting of is greater than the untwisting moment of the yarn in the desired twisted state.
In addition, the following points should be noted. This means that a thread, especially a thread under tension, is a rotationally elastic object that produces a defined untwisting moment in response to twist. This untwisting moment is related, inter alia, to the strength of the twist and to the degree of heating in the false-twisting zone.

Furthermore, according to the present invention, it is possible to adjust the yarn tension before and after the friction false twister, and in particular the ratio of this yarn tension, regardless of the twisting, conveying and slipping conditions. The prerequisite in this case is that in order to obtain a given crimp, the twist strength must first be determined and then a given optimal base angle alpha in relation to the denier must be determined. (See Figure 6). moreover,
It is also assumed that the yarn speed is generally determined by machine data and by process data, such as, for example, the residence time of the yarn on a heating plate at a given heating temperature and heat conduction value. It is a condition. The circumferential speed of the disc in the pressing range is then adjusted to a value optimal for the thread tension. For this purpose, in an advantageous embodiment of the invention, the ratio between the disk speed D and the yarn speed Y in the pressing range is D/Y=1/CoS alpha (1±20%), in which case the alpha is the base angle which defines the desired twisting angle of the yarn in the twisted state or the position of the pressing device. It is also advantageous in this case for the value of D:Y to be between 1.5 and 2.

Next, embodiments of the present invention will be described with reference to the drawings.

The friction false twister shown in FIGS. 1a and 1b consists of a rigid disk 1 and a flexible disk 2. The friction false twister shown in FIGS. The axes 3 and 4 of both discs 1 and 2 are, respectively,
Rotatably supported by bearings 5 and 6, both discs 1,
2 is driven via belt pulleys 27 and 28 by a drive device (not shown). The rigid disc 1 has a friction lining 26, which consists of, for example, rubber, Vulkollan, wear-resistant metal, plasma coating, ceramic coating, nickel-diamond coating, or the like. .

The flexible disc 2 consists of a material or possibly a material composite, which on the one hand absorbs the tensile forces caused by centrifugal forces, but on the other hand can easily bulge and/or distort. . For example, the disk 2 is a rubber disk having a thickness of 0.5 to 2 mm. In this case, this rubber disk has a cord thread insert on its back side to increase its tensile strength, or it has a spring steel disk with a thickness of at least 1 mm and a ring-shaped friction lining. .

The back side of the flexible disc 2 is loaded by the pressing surface 7 of the pressing device 10 and thereby bulges and deflects towards the thread 14. As a result, the thread 14 is trapped in a narrow area between the flexible disc 2 and the ring-shaped friction lining of the rigid disc 1. The pressing device 10 includes a cylinder 9 and this cylinder 9.
It consists of a piston 8 which moves within and has a recess 13 on the side of the pressure surface 7 facing the disk 2. The pressurized air connection 11 is provided with an adjustable pressure control device 72 by means of which, on the one hand, the piston 8 is pressed towards the flexible disk 2, and on the other hand, the compressed air is forced into the recess 13. compressed within. This produces, on the one hand, a defined clamping force N (see FIG. 4) and, on the other hand, compressed air lubrication and compressed air between the pressing surface 7 and the flexible disc 2. A cushion is formed.

The thread 14 is guided by the entering thread guide 22 to the disk 1,
2 (see FIG. 1a) at right angles to the common axial plane of the two axes.

The thread 14 runs parallel to the common axial plane of the two axes through the entry thread guide 22 (the first
(see figure b).

In the illustrated embodiment, the bearings 5, 6 and the pressing device 1
0 is adjustable (see Figure 3). For this purpose, the bearings 5, 6 have guides by means of which they can be slid along parallel guide rods 15, 16. Set screws 17, 18 are provided to fix the bearings 5, 6 in position. With the arrangement described above, both discs 1, 2 can be moved between the inner end position 29 and the outer end position 30 shown in FIGS. 1a and 1b. This moving distance is limited by a stopper 31. Advantageously, the positioning is such that the axes or axes of the two discs 1, 2 are each equidistant from the thread line.

Similarly, the pressing device 10 can also be slid along a guide rod 19 with a square cross section, i.e. in the end position 2.
4.1 and 25.1 and 24.2 and 25.2 and is positioned by a set screw 20.

In FIG. 1a, the end position 2 of the pressing device 10
4.1 and 25.1 correspond to the end position 29 of the discs 1, 2, and end positions 24.2 and 25.2 correspond to the end position 30. Rotation direction 2 between disk 1 and disk 2
3 is the opposite, at position 24 of the pressing device 10 Z
Twist is applied to the yarn fed with an S twist at position 25 of the pressing device 10 . If it is desired to change the ratio between twist and yarn feed when adding a Z twist to the yarn, the pressing device 10 is moved between the end positions 24.1 and 24.2. If, on the other hand, it is desired to change the ratio between twist and yarn feed when adding an S twist to the yarn, the pressing device 10 is moved between the end positions 25.1 and 25.2.

In other words, the end positions 29, 30 of the discs 1, 2 and the end positions 24.1 to 24.1 for Z twisting of the pressing device 10.
24.2 and end position 2 for S twist
5.1 to 25.2, any intermediate position convenient for the desired false twisting method can be selected. I will discuss this in more detail later.

It is clear that the formation of the twist by the false twister is related to the distance between the yarn guides, and in particular to the distance between the twisting point, ie the point where the yarn is given a twist, and the incoming yarn guide 22. It is. This twisting point is determined by the position of the pressing device 10 in the false twisting machine according to the invention. In order to maintain a constant distance between the input yarn guide 22 and the pressing device 10, the input yarn guide 22 and the pressing device 10 are mechanically connected to each other. This means that 1a
It can be seen from FIG. 2 that it relates to a friction false twister with the yarn running shown in the figure. In this case, the spacer rod 21 is in the lower end position 25.1 with the pressure device 10
Even in the case where the thread guide 22 is in contact with the disks 1 and 2, the length must be such that the thread guide 22 does not come into contact with the discs 1 and 2.

In the case of yarn running in the embodiment of FIG. 1b, S
Entering yarn guide 2 when switching from twist to Z twist
2 is offset to the other side of an axial plane common to both axes of the discs 1, 2.

In the thread running shown in FIG. 1b, it is necessary to change the direction of rotation of the discs 1 and 2 in order to switch from S twist to Z twist. The direction of rotation of disks 1 and 2 is indicated by arrows S and Z.
It is shown by.

If the distance between the axes of both discs 1 and 2 and/or the distance between the pressing device 10 and the common axial plane of both discs 1 and 2 are variable, the operating conditions can be optimally adjusted. In this case, it must be kept in mind that both axes and the pressing device 10 are located at each corner point of the isosceles triangle, and as a result, the velocity components applied by the disks 1 and 2 have equal values. It means that it has. In this case, it is particularly advantageous if there is synchronism between the distance between the axes and the distance of the pressing device 10. This is illustrated in FIG. 3 by the coupling rods or pivot levers 67, 68. In most cases, it is sufficient to vary the distance between the pressing device 8 and a common axial plane. However, if this does not result in optimal operating conditions, it is also possible to vary the center distance in addition.

The axes of the two disks 1, 2 of the false twister are either parallel or somewhat intersecting each other. Considering that the two axes slightly intersect, the expression "common axial plane" is not completely correct, but since the angle between the two axes that intersect with each other is extremely small, We will use the expression "common axial plane".

In order to further improve the operating condition, the pressing device 1
The crimping force of 0 is adjustable. That is, this pressing force is variable by adjusting the air pressure via the pressure control device 72 (see FIGS. 2 and 3).
Furthermore, the rotational speed of the discs 1, 2 as well as the yarn feeding speed can be adjusted.

In order to obtain the desired state of movement in the geometrical arrangement of the two discs 1, 2 and the pressing device 10, it is necessary for the yarn running in FIG. 1a to have an angle alpha of 50° to 65°. It is good if it is between ゜. In this case, it is advantageous if the distance between the axes and the pressure device 10 are arranged in such a way that the two axes form the end points of the base of an isosceles triangle, and the pressure device 10 is located at the apex. It is also advantageous if the base angle alpha of this isosceles triangle is equal to the twist angle of the yarn in the twisted state. The twisted state of the yarn is shown in FIG. 5, where the twist angle is indicated by alpha. It is clear that the thread, in the twisted state, shortens its length and increases its diameter. Therefore, the angle alpha in the twisted yarn is the twist angle obtained from the twist angle of the untwisted yarn or by calculation from the adjusted yarn running speed, number of twists, and diameter of the finished yarn. smaller than The empirical values for adjusting the base angle alpha are shown in relation to the yarn denier and the desired twist in the diagram of FIG. The number of twists (TPM) is taken on the vertical axis.

Adjusting the friction false twister as described above allows the yarn to be conveyed and twisted with even slip.

For slip-free transport and twisting,
Another requirement according to the invention is that the torsional moment exerted on the yarn by the friction disk MS=N・
The pressing force of the pressing device 10 may be adjusted to a value that ensures that μ·D _F /2 exceeds the yarn untwisting moment MF. This relationship is shown in FIG. In this case, the signs are respectively: N is the vertical pressing force, MS is the torsion moment, μ is the coefficient of friction, MF is the untwisting moment caused by the elasticity of the yarn, D _F is the yarn diameter, and N' is the pressing device 10.
This is the pressing force due to

What has been described above ensures that an optimum twisting state can be set for the texturing process. A further aim of the invention is to optimally adjust the thread tension. This is based on the recognition that in all false twisting machines known up to now, neither in spindle false twisting machines nor in the known friction false twisting machines, it is not possible to freely select the yarn tension state. Rather, up until now the yarn tension state has also been associated with the twist state. It is generally known to adjust the yarn tension before and after a friction false twister by adjusting the ratio of disk speed to yarn speed. On the other hand, in the friction false twisting machine of the present invention, the velocity vector of the friction disk is oriented transversely to the yarn axis.
Therefore, it has a component in the conveying direction and a component in the twisting direction. Since the twist state is not changed in the friction false twister of the present invention, that is, the angle formed by the motion component is not changed, the friction false twister can be adjusted by adjusting the yarn speed or the circumferential disk speed. You can freely adjust the thread tension in the front and back. Advantageously, the relationship between disk speed D and thread speed Y is D/Y=1/COS alpha (1±20%).

In this case, alpha is the desired twisting angle in the twisted state or the base of the previously adjusted isosceles triangle formed by the two disk axes and the pressing device.

Finally, the friction false twister can also be operated with the yarn run shown in FIG. 1b. In this case, the geometric operating position according to the invention is obtained in that the angle alpha is 1/2 of the apex angle of the isosceles triangle formed by the two disk axes and the pressing device. In the case of this embodiment according to FIG. 1b, it is advantageous if the angle alpha is equal to the twisting angle alpha of the yarn in the twisted state.

[Brief explanation of the drawing]

FIG. 1a is a plan view of a friction false twister with yarn running perpendicular to an axial plane common to both axes of rotation, and FIG. 1b is a plan view of a friction false twister with yarn running parallel to said common axial plane. A plan view of the machine, Fig. 2 is a partial sectional view of the pressing device equipped with an incoming yarn guide, Fig. 3 is a longitudinal sectional view of the friction false twisting machine of Fig. 1a, and Fig. 4 shows various forces and moments in the pressing range. FIG. 5 is a diagram showing the yarn portion in a twisted state, and FIG. 6 is a diagram showing the relationship between base angle alpha, desired twist formation, and yarn denier. 1, 2... Disc, 3, 4... Shaft, 5, 6... Bearing, 7... Pressing surface, 8... Piston, 9... Cylinder, 10... Pressing device, 11... Compressed air connection Part, 12... Air passage, 13... Notch, 14
... Thread, 15, 16 ... Guide rod, 17, 18 ...
Set screw, 19...guide rod, 20...set screw,
21... Spacer rod, 22... Entry thread guide, 23... Rotation direction, 24, 25... Position, 2
4.1, 24.2, 25.1, 25.2... End position, 26... Friction lining, 27, 28...
Belt wheel, 29, 30...Terminal position, 31, 32
... Stopper, 33 ... Yarn running direction, 67, 68
...Swivel lever, 72...Pressure control device, N...
Crimping force, N'...pressing force, S, Z...arrow, MS...
...Twisting moment, MF...Untwisting moment,
DF...Thread diameter, μ...Friction coefficient, D...Disk speed, Y...Thread speed.

Claims (1)

[Claims] 1. A friction false twisting machine equipped with two rotating disks that sandwich yarn between mutually opposing end surfaces,
One disc is made of a flexible and elastic material,
In the case where the disk is pressed against the other disk by a pressing device, the distance between the axes of the two disks 1 and 2 is variable and/or the pressing device 10 and each of the disks 1 and 2 are A friction false twisting machine characterized in that the distance from a plane passing through the axis is variable along the yarn running direction. 2. The distance between the axes of the discs 1 and 2 and/or the distance between the pressing device 10 and an axial plane common to the axes of both discs 1 and 2 is such that the distance between each axis of both discs 1 and 2 and the pressing device 10 is A friction false twister according to claim 1, wherein the friction false twister is adjusted so as to form a point at each corner of an isosceles triangle. 3 The distance between the axes of the discs 1 and 2 and/or the distance between the pressing device 10 and the common axial plane
2 and the pressing device 10 are adjusted so as to form respective corner points of an isosceles triangle having a base angle between 55° and 60°. Friction false twisting machine. 4 The distance between the axes of the discs 1 and 2 and/or the distance between the pressing device 10 and the common axial plane are such that both discs 1,
2 and the pressing device 10 are adjusted so that they are located at each corner of an isosceles triangle, and the base angle of the isosceles triangle corresponds to the twist angle of the thread in the twisted state. The friction false twisting machine according to item 1. 5 Pressure force of the pressing device 10 and eventually the disks 1 and 2
In order to obtain the desired twist state (twist angle alpha) in the twisted state, the normal force applied to the yarn 14 by ,2 by thread 14
5. The friction false twisting machine according to claim 4, wherein the twisting moment applied to the yarn is adjusted to be greater than the untwisting moment of the yarn. 6. Friction false twisting according to claim 1, wherein the yarn tension before and after the friction false twisting machine is brought to the target value by adjusting the yarn speed Y and/or disc speed D in the crimping range. Machine. 7 The ratio of disk speed D to thread speed Y in the crimping range is D:Y=(1:COS alpha)(1±20%)
7. The friction false twisting machine according to claim 6, wherein the twist angle is adjusted so that the alpha is the desired twist angle of the yarn in the twisted state. 8 In the crimping range, the ratio of the disc speed D to the thread speed Y is such that the value of D:Y is 1.5 by adjusting the rotational speed of the discs 1 and 2 when the thread speed Y is predetermined.
7. The friction false twisting machine according to claim 6, which is adjusted to be between .about.2.