Apparatus for the false twisting of threads using friction disks

A disk combination which permits a thread false-twisting device to be operated at a high withdrawal speed is disclosed. The false-twisting device has three parallel rotatable shafts. On a first shaft is a first inlet guide disk for guiding entering thread into a thread path. A second inlet guide disk on a second shaft guides the thread along the path. After the second inlet guide disk, a first working disk on the first shaft begins false-twisting the thread. The first working disk may be one of five working disks, each of which is positioned in the rotational direction from the preceding disk. After the last of the working disks the exiting thread contacts an outlet guide disk, also positioned in the rotational direction from the preceding disk. The disks may be made of a soft material, such as polyurethane, or may be rigid disks coated with a hard material such as nickel containing diamond particles. The thread can be drawn through the device at a speed in excess of 600 meters per minute.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a device for the false-twisting of thread by using 
friction disks. More specifically, the invention relates to defined 
combinations of disks for false-twisting thread. 
2. Description of the Prior Art 
German Application DE OS No. 25 27 216 describes an example of a disk 
combination with two shafts in which a thread guide disk must be arranged 
in a prescribed manner on one of the shafts. This arrangement of the disks 
is customary throughout the world and does not result in any problems when 
operated at the speeds of rotation and the withdrawal speeds used prior to 
the present time. 
It is also conventional to operate with a plurality of thread guide disks 
on the thread inlet side, as shown in FAG publication No. DB 849, a 
publication of the assignee hereof. For clockwise rotating disks, each of 
the thread guide disks is strictly arranged in the clockwise direction 
from the preceding disk, for operating under certain given conditions, 
such as speed of rotation of the disks, nature of the disks, speeds of 
withdrawal and thread supplies. Such an arrangement has been used to 
obtain the required quality of final thread. 
German Application DE OS No. 26 58 034 describes an inlet or outlet disk as 
a thread guide disk without indicating a definite arrangement of the disk 
within the unit. Furthermore, the curved contact surfaces in a heating 
body have direct contact with the thread. Traces of finishing agents are 
deposited on the curved contact surfaces, which necessarily contributes to 
agitating the movement of the thread. Up to now, these deposits of 
finishing agents have not contributed to any particular disturbances in 
the movement of the thread at the ordinary withdrawal speeds, which remain 
below a maximum of 600 meters per minute. At higher speeds, however, the 
deposits cause the thread to become very agitated. 
The movement of the thread may be stabilized by thread guide disks arranged 
on the inlet and/or the outlet side of the pathway of the thread across 
the array of disks. Conventional disk combinations have as many as ten or 
more working disks for false-twisting the thread. In addition, there may 
be one, two or even three guide disks which are combined in series on the 
inlet side before the thread reaches the working disks. For clockwise 
rotating disks, each of the thread guide disks in the pathway of the 
thread across the disks, is always arranged in the clockwise direction of 
rotation from the preceding disk, as shown in FIGS. 1-3 hereto. As shown 
in FIG. 3, when one disk is used, it is mounted on shaft 3. When two disks 
are used as shown in FIG. 2, the first is mounted on shaft 2 and the 
second on shaft 3, clockwise from shaft 2. When three thread guide disks 
are used, as shown in FIG. 1, the third disk is arranged on shaft 1 
clockwise from shaft 3. Only one thread guide disk is conventionally used 
on the thread outlet side. 
Each combination of disks is described by an abbreviation. For example, if 
five working disks are used, the combinations described above could be 
described by the following abbreviations: 
(A) 1-5-1 
(B) 2-5-1 
(C) 3-5-1 
In each abbreviation, the first number indicates the number of thread guide 
disks on the inlet side, the second number the number of working disks on 
the outlet side of the inlet guide disks and the third number the number 
of thread guide disks on the outlet side of the working disks. 
All of these combinations are used throughout the world for different 
threads and do not result in any particular difficulties with thread 
withdrawal speeds not exceeding 600 meters per minute. 
Recently, there has been demand for higher withdrawal speeds, of 800 meters 
per minute and more. At these speeds, the thread movement can no longer be 
stabilized with only the thread guide disks described above. Although the 
thread can be caused to start up with one disk, its movement remains very 
agitated and this leads to frequent breaks in the thread. When two disks 
are used, it is barely possible to start up the thread, particularly if 
the working disks are made of a soft material. When three thread guide 
disks or working disks of soft material are used, it is impossible to 
start up the thread. 
In all three cases indicated, the combination of guide disks results in 
agitation of the thread and does not allow the movement of the thread to 
stabilize. The thread movement cannot be stabilized even by using more 
than five working disks. 
SUMMARY OF THE INVENTION 
One object of the invention is, therefore, to provide a combination of 
disks arranged to permit high thread withdrawal speed while providing a 
suitable quality of thread. 
This and other objects of the invention are achieved by providing a disk 
combination having the first of two guide disks on the same shaft as a 
first working disk on the inlet side of a thread false-twisting device. 
The disk combination guides the thread into and along a thread path for 
false-twisting between the three shafts of the device. The first inlet 
guide disk and the first working disk are on a first shaft, while the 
second inlet guide disk is on a second shaft and is located between the 
first guide disk and the first working disk. The second shaft may be 
positioned opposite the direction of rotation from the first shaft around 
the triangle defined by the three shfts. Toward the outlet from the inlet 
guide disks are a plurality of working disks, starting with the first 
working disk on the first shaft, for false-twisting the thread as it 
passes along the thread path. Each of the following working disks may be 
on the succeeding shaft positioned around the triangle from the preceding 
disk. The last of the working disks may be followed by an outlet guide 
disk for guiding the thread as it exits from the thread path. 
The invention is based on the discovery that the arrangement of disks 
described above makes it possible to withdraw thread or yarn from nearly 
all supplies at a speed far greater than 600 meters per minute. As used 
herein, the word "thread" includes both thread and yarn, since the 
invention may be used for both. The disk combination of the invention 
avoids difficulties in the thread movement, especially if knotted thread 
is used. The first guide disk prevents these difficulties by bringing the 
entering thread past the second guide disk to the first working disk, 
which is rotating in the same direction on the same shaft as the first 
guide disk. Both the first guide disk and the first working disk may 
rotate to bring the thread inward, or toward the second guide disk. This 
arrangement provides an extremely gentle deflection of the thread at the 
inlet. 
The working disks may have their contact surfaces comprising a soft 
material for contacting the thread, such as polyurethane. Such a soft 
material imparts greater twist to the thread, but the disk combination of 
the invention permits high withdrawal speeds even with such soft 
materials. Furthermore, the invention provides an additional economic 
advantage, because the gentle deflection of the entering thread leads to 
substantially longer useful lifetimes for the working disks. 
The working disks may alternatively have a rigid or hard material for 
contacting the thread. For example, the body of each working disk may be 
rigid and may be coated with a hard layer of nickel containing diamond 
particles. 
Another advantage of the disk combination of the invention is that it 
stabilizes the movement of the thread to eliminate agitation. This is 
beneficial because the deposits of finishing agent in the heating 
channels, described above, are greater at greater thread withdrawal 
speeds. At speeds greater than 600 meters per minute, these deposits would 
greatly agitate the thread movement, but the disk combination of the 
invention stabilizes the thread movement. Therefore, the thread is 
stabilized as it passes through the false-twisting device and is properly 
twisted. 
Another advantage of the invention is that no more than five working disks 
are necessary for twisting nearly all threads and yarns. Previously, as 
many as ten working disks were necessary. With five working disks, either 
an S-twist or a Z-twist may be obtained. For an S-twist, the shafts rotate 
clockwise when viewed from the inlet. For a Z-twist, the shafts rotate 
counter-clockwise when viewed from the inlet. In either case, the working 
disks may be followed by an outlet guide disk for guiding the exiting 
thread. 
Other objects, features and advantages of the invention will be apparent 
from the following description, together with the accompanying drawing and 
the appended claims.

DETAILED DESCRIPTION OF PRIOR ART EMBODIMENTS 
The general operation of inlet guide disks for thread false-twisting 
devices may be understood from FIGS. 1-6, which show several prior art 
disk combinations. FIGS. 1-3 show disk combinations 10, 20, 30 for 
producing an S-twist, while FIGS. 4-6 show combinations 40, 50, 60 for 
producing a Z-twist. As the disks are viewed from the top, only the 
circular profile of the upper disk on each shaft is shown. The guide disks 
are shown in solid profile, while the working disks are in dashed line 
profile. As shown, each disk rotates in a clockwise direction as viewed 
from the inlet end or top. Also shown in dashed lines are the shafts and 
pulleys that are used to drive the shafts. 
FIG. 1 shows a conventional 3-5-1 disk combination 10 for producing an 
S-twist. The three shafts 11, 12 and 13 support respective guide disks 14, 
15 and 16. As shown in FIG. 1, the thread entering from above first 
encounters inlet guide disk 14, then inlet guide disk 15, and finally 
inlet guide disk 16 before it reaches the working disks (not shown). The 
thread passes between the disks in the central area. 
FIG. 2 similarly shows a conventional 2-5-1 disk combination for producing 
an S-twist. The shafts 21, 22 and 23 support respective disks 27, 24 and 
25. The entering thread first encounters inlet guide disk 24, then inlet 
guide disk 25, and then the thread goes to the first working disk 27. As 
in FIG. 1, the direction of rotation of the disks is clockwise as viewed 
from the inlet end or top. Therefore, in relation to the triangle whose 
corners are defined by the three shafts 21, 22 and 23, the second inlet 
guide disk 25 is positioned in the clockwise rotational direction from the 
first guide disk 24, while the first working disk 27 is in turn positioned 
in the clockwise rotational direction from the second guide disk 25. As a 
result, the first guide disk 24 and the first working disk 27 are on 
different shafts. 
FIG. 3 shows a conventional 1-5-1 disk combination for producing an 
S-twist. Here, shafts 31, 32 and 33 support respective disks 37, 38 and 
34. In this case, the only guide disk is inlet thread guide disk 34. After 
the thread passes guide disk 34, it meets first working disk 37 and then 
meets second working disk 38. As can be seen from FIG. 3, first working 
disk 37 is positioned in the clockwise direction of rotation from guide 
disk 34, and second working disk 38 is in turn positioned in the clockwise 
rotational direction from first working disk 37. 
As can be seen from FIGS. 1-3, shafts 12, 23 and 33 may also hold 
respective drive whorls 19b, 29b and 39b. These whorls may each be driven 
by a respective belt 19a, 29a and 39a for producing the clockwise 
rotation, as shown. The other shafts are belt driven by the whorl carrying 
shaft. 
In contrast to FIGS. 1-3, FIGS. 4-6 show conventional disk combinations for 
producing Z-twists. As can be seen by comparing FIGS. 4-6 with FIGS. 1-3, 
the direction of disk rotation is counter-clockwise, as viewed from the 
inlet or top end, rather than clockwise. 
FIG. 4 shows a conventional 3-5-1 combination for producing a Z-twist. 
Shafts 41, 42 and 43 support respective disks 44, 46 and 45. The entering 
thread first encounters first inlet thread guide disk 44, then second 
inlet thread guide disk 45, and finally third inlet guide disk 46, before 
reaching the working disks. As can be seen by comparing FIG. 4 with FIG. 
1, the three guide disks are arranged in each case so that, in relation to 
the triangle defined by the shafts, the second guide disk is positioned in 
the direction of rotation from the first guide disk and the third guide 
disk is positioned in the directiion of rotation from the second guide 
disk. This relationship holds even though the directions of rotation are 
different for the two conventional combinations, being clockwise in FIG. 1 
and counter-clockwise in FIG. 4. 
FIG. 5 shows a conventional 2-5-1 disk combination for producing a Z-twist. 
Shafts 51, 52 and 53 support respective disks 57, 55 and 54. The entering 
thread first contacts first inlet guide disk 54, then second inlet guide 
disk 55. From guide disk 55, the thread proceeds to first working disk 57. 
In this arrangement, the second guide disk 55 is positioned in the 
counter-clockwise direction of rotation from the first guide disk 54 while 
the first working disk 57 is positioned in the direction of rotation from 
the second guide disk 55. As a result, the first guide disk 54 and the 
first working disk 57 are on different shafts. 
FIG. 6 shows a conventional 1-5-1 disk combination for producing a Z-twist. 
Shafts 61, 62 and 63 support respective disks 67, 64, and 68. The entering 
thread first contacts first inlet guide disk 64, from which it passes to 
first working disk 67 and then to second working disk 68. Here again, the 
first working disk 67 is positioned in the counter-clockwise direction of 
rotation from the guide disk 64 and the second working disk 68 is 
positioned in the direction of rotation from the first working disk 67. 
FIGS. 4-6 also show shafts 41, 51 and 61 holding respective drive whorls 
49b, 59b and 69b. These whorls 49b, 59b and 69b may be driven by 
respective belts 49a, 59a and 69a for causing shafts 41, 51 and 61 to 
rotate in the counter-clockwise direction. 
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
The disk combinations of the invention can be understood from FIGS. 7-10. 
FIGS. 7-8 show a disk combination for producing an S-twist, while FIGS. 
9-10 show a disk combination for producing a Z-twist. In both cases, 
however, a 2-5-1 disk combination is provided, with the first working disk 
and the first inlet guide disk on the same shaft. Between the first inlet 
guide disk and the first working disk is the second inlet guide disk on 
another shaft, which may be positioned in a direction opposite the 
rotational direction from the first inlet guide disk. 
FIG. 7 shows the S-twist disk combination 70 of the invention. Shafts 71, 
72 and 73 support respective disks 74, 77 and 75. First and second inlet 
thread guide disks 74 and 75 are shown in solid profile. First working 
disk 76 cannot be seen because it is on shaft 71 beneath first guide disk 
74. Second working disk 77, however, is positioned in the clockwise 
direction of rotation from first working disk 76, as shown. Belt 79a 
drives whorl 79b on shaft 73. 
FIG. 8 shows the S-twist disk combination 70 of FIG. 7 in front view, with 
the parts somewhat separated for clarity. As shown in FIG. 8, the first 
disk at the inlet (top) side of the false-twisting device is first inlet 
guide disk 74 on shaft 71. After the thread encounters disk 74, it passes 
to second inlet guide disk 75 on shaft 73. From there it psses back to 
first working disk 76, also mounted on shaft 71, which is the first in a 
series of five working disks 76, 77, 78, 79 and 80, each of which is 
positioned on the next succeeding shaft around the triangle defined by the 
shafts from the preceding disk. In FIG. 8, each working disk is positioned 
in the clockwise direction of rotation around the triangle from the 
preceding disk. After the last working disk 80, outlet guide disk 81 on 
shaft 73 is also positioned in the direction of rotation from the 
preceding working disk, which is the last working disk 80. Belt 79a drives 
whorl 79b, as shown. 
As discussed above, the invention is based on the discovery that this disk 
combination permits a high speed of thread withdrawal from the thread 
supply over a broad range of types of thread. In passing from first guide 
disk 74 to first working disk 76 on the same shaft, the thread is gently 
deflected by second guide disk 75 on another shaft. This deflection, 
however, does not interfere with the rapid withdrawal of the thread, and 
instead serves to stabilize the thread movement. 
FIG. 9 shows the Z-twist disk combination of the invention. Shafts 91, 92 
and 93 support respective disks 94, 95 and 97. Entering thread first 
contacts first inlet guide disk 94, and then contacts second inlet guide 
disk 95. The thread then proceeds to first working disk 96, which is 
beneath first guide disk 94 on shaft 91. Then the thread proceeds to 
second working disk 97. As described in relation to FIG. 7, the second 
guide disk 95 is positioned on shaft 92 in a direction opposite the 
rotational direction from the first guide disk 94. 
FIG. 10 shows the Z-twist disk combinaion 90 of FIG. 9 in a front view 
similar to FIG. 8. The entering thread encounters first inlet guide disk 
94, then second inlet guide disk 95. From guide disk 95, the thread 
proceeds past five working disks 96, 97, 98, 99 and 100, each of which is 
positioned on the next succeeding shaft around the triangle defined by the 
shafts from the preceding disk. In FIG. 10, each working disk is 
positioned in the counter-clockwise direction of rotation around the 
triangle from the preceding disk. In addition, outlet guide disk 101 is 
positioned on shaft 92 in the direction of rotation from the preceding 
disk, which is the last working disk 100. Shaft 91 is driven by belt 99a 
through whorl 99b. FIG. 10 also shows more fully how the shafts may be 
connected by drive belts 102 and 103, and how shafts 91, 92 and 93 are 
mounted on frame 104. This arrangement is merely illustrative, however, as 
the shafts could be rotatably mounted and interconnected in many ways. 
As discussed above, the Z-twist disk combination 90 of the invention, like 
the S-twist disk combination 70 shown in FIGS. 7 and 8, includes the basic 
combination of a first inlet guide disk on the same shaft as the first 
working disk. Between them is a second inlet guide disk, which may be 
positioned in a direction opposite the rotational direction from the first 
guide disk. After the first working disk are additional working disks, 
each positioned on the next succeeding shaft around the triangle defined 
by the shafts from the preceding disk. 
FIG. 11 shows in greater detail the relationship between two adjacent disks 
110 and 112 of the invention. As shown, a thread 114 passes across the 
slightly rounded edge 116 of disk 110 and then across the slightly rounded 
edge 118 of disk 112. The disks 110 and 112 have adjacent respective sides 
120 and 122, both of which are flat. These adjacent sides 120 and 122 are 
spaced apart by a distance which preferably does not exceed 0.5 
millimeters. In addition, the edges 116 and 118 which contact thread 114 
may have any appropriate texture. Specifically, if disks 110 and 112 are 
working disks, their edges may each be a soft material, such as 
polyurethane. When the disks of such a material are used, their lives are 
lengthened by the invention, because the thread is easily threaded through 
the false-twisting until and because of the stable operation at high 
speeds of withdrawal. On the other hand, disks 110 and 112 may consist of 
a rigid material, coated with a hard substance such as nickel containing 
diamond particles. 
Although the present invention has been described in connection with a 
plurality of preferred embodiments thereof, many other variations and 
modifications will now become apparent to those skilled in the art. It is 
preferred, therefore, that the present invention be limited not by the 
specific disclosure herein, but only by the appended claims.