Method and means for mounting a drive roll in a high speed winder

The present invention provides a way of mounting a drive roll in a high speed winder, in which a drive roll bracket for holding a drive roll is pivotally supported by a pivot whose axis is an intersection line between a vertical plane equally dividing a distance between opposite remote end surfaces of a wound thread package and a horizontal plane that is tangential to a bottom surface of the drive roll or a horizontal plane in the proximity thereof, and a press contact force between said drive roll and the bobbin holder shaft or wound thread package is applied entirely by the intermediary of said pivot.

BACKGROUND OF THE INVENTION 
FIG. 1 is a side cross-sectional view showing one example of winders in the 
prior art, in which a drive roll 1 is held from a drive roll bracket 2, 
and it also forms a motor-containing roll which rotates when an electric 
power is received from a power source 3. The drive roll bracket 2 has its 
one end fixedly secured to a slider 4. Accordingly, if the slider 4 slides 
vertically along a guiderail 5, then the drive roll 1 also slides 
vertically together with the bracket 2. Reference numeral 6 designates a 
bobbin holder, which is rotatably supported by a bearing 8 fitted in a 
frame 7, and which also can tightly fit and hold a bobbin around its outer 
circumference by publicly-known means. Accordingly, if the drive roll 1 is 
driven as press contacted onto the surface of a bobbin (not shown) held 
around the outer circumference of the bobbin 6, then the bobbin and the 
bobbin holder rotate at such rotational speed that they have a 
circumferential speed equal to the circumferential speed of the drive roll 
1, so that when a yarn is supplied while being traversed on the 
circumference of the bobbin, the yarn is positively wound to form a wound 
thread package 9. Though various means (not shown) have been known with 
respect to the structure for applying the press contact force against the 
wound thread package 9 and the bobbin to the drive roll 1, in any way it 
is an essential condition for obtaining a wound thread package of good 
shape to apply a press contact force P that is uniform along the widthwise 
direction of winding of the wound thread package 9 and that is 
appropriate. Especially, in case that two or more wound thread packages 9 
are formed on a bobbin holder 6 as shown in FIG. 1, or even in case that a 
single wound thread package 9 is formed if the width of winding becomes 
large, then the press contact force is apt to become uneven along the 
direction of width of the winding, so that a wound thread package of good 
and uniform quality is hardly obtained. In addition, for the purpose of 
applying a press contact force that is uniform along the direction of 
width of the winding, it is necessary that the bobbin holder 6 and the 
drive roll 1 should maintain a very good parallelism over the entire 
region of the sliding interval of the slider 4, and further, it is 
necessary that the bobbin holder 6 which has a smaller diameter than the 
drive roll 1 and which is cantilever supported should have a higher 
rigidity and should not be flexed by the press contact force P and the 
weight W of the wound thread package. Accordingly, it has been heretofore 
necessitated to raise the design rigidity of the bobbin holder 6 as high 
as possible to maintain high working accuracies, such as straightness, 
rightness, fitting tolerance, etc. of the respective parts, such as the 
frame 7, guiderail 5, slider 4, drive roll bracket 2 and drive roll 1, and 
also to raise the accuracy in assembly. The above-mentioned is an example 
which has been manufactured and used up to a winding speed of about 2,000 
m/Min. though it has been accompanied with difficulties. However, 
recently, in the spun yarn winding process for synthetic fiber yarns, a 
spin-draw system or a POY (partially orientated yarn) system has been 
developed. In these systems, a winder for a high speed large package (a 
large wound thread package) having a winding speed of 3000-4000 m/Min. is 
required, and further, if the rotational speed of the bobbin holder is 
raised up to 12,000-14,000 rpm and if the cantilever projection length is 
extended up to 350-500 mm, then with the simple bearing support, as shown 
in FIG. 1, the bobbin holder would resonate within the operating 
rotational speed range, so that a violent vibration is generated which 
makes winding impossible. Therefore, a winder, as shown in FIG. 2, has 
been proposed. 
Explaining now the principles of a way of avoiding said resonance with 
reference to FIG. 2, reference numeral 10 designates a motor-containing 
drive roll held by a drive roll bracket 11, and said drive roll bracket 11 
has its one end fixedly secured to a slider 12. This slider 12 is 
constructed in such manner that it can slide vertically up and down along 
a guiderail (not shown) and it can apply a press contact force to a bobbin 
and a wound thread package (not shown) on a bobbin holder 13 with 
publicly-known means, and with respect to this point, the construction is 
similar to that shown in FIG. 1. Reference numeral 14 designates a bobbin 
holder shaft for the bobbin holder 13, which is rotatably supported by 
bearings 17 which are resiliently supported from a frame 15 via springs 
16. The thus constructed bobbin holder 13 and bobbin holder shaft 14 in 
FIG. 2 can have their lower order resonant rotational speed set as an 
specific value within a given range by appropriately selecting their 
weight distribution and the elasticity of the springs 16, and therefore, 
if this is set at a value lower than the operating range, then the 
vibration that is harmful for winding can be prevented. In addition, since 
the bobbin holder 13 and the bobbin holder shaft 14 are resiliently 
supported from the frame 15 via springs 16, they can maintain their 
straightness without being flexed even under a lower order resonant state 
(lower than the operating range) or even at an operating state exceeding 
the resonant point. However, in order to obtain a good wound thread 
package with a winder having such construction, the problem of incorrect 
parallelism between the drive roll 10 and the bobbin holder 13 must be 
resolved. 
FIG. 2 shows an initial winding state where a wound thread package is not 
yet formed. Since the bobbin holder 13 and the bobbin holder shaft 14 are 
inclined in the direction of a press contact force P while almost 
maintaining their straightness owing to compression of the springs 16 when 
they are applied with the press contact force P by the drive roll 1, the 
press contact force distribution on the bobbin is as shown by a number of 
graduated arrows in FIG. 2, that is, the force is larger on the bearing 
side and it is smaller towards the opposite side. Then, as the wound 
thread package 18 grows and its weight W becomes successively larger, as 
shown in FIG. 3, the bobbin holder 13 and the bobbin holder shaft 14 are 
integrally inclined substantially, so that almost all the press contact 
force P is applied to the end of the wound thread ball on the bearing 
side, and thus there occurs irregular traverse or yarn drop along the end 
face of the wound thread package on the bearing side, which makes the 
winding impossible. Strengthening the springs 16 to reduce the inclination 
of the bobbin holder 13 would result in the rise of a resonant point, and 
since high speed winding becomes impossible because of violent vibration, 
this approach cannot be a solution. As described above, in a high speed 
winder, the way of mounting the drive roll in the prior art had a defect 
in itself. 
SUMMARY OF THE INVENTION 
The inventors of the present invention encountered the problem of vibration 
of the bobbin holder in the course of development of a high speed winder, 
and so they have succeeded in the solution of this problem by making 
improvements in the way of supporting a bobbin holder shaft. When a yarn 
was practically wound at a high speed according to the above-described 
method, yarn drop along an end face or deformation occurred and thus a 
good wound thread package could not be obtained. It has been found that 
this is caused by the fact that the bobbin holder shaft is inclined 
depending upon the press contact force and the weight of the wound thread 
package because it is resiliently supported and thereby the press contact 
force of the drive roll becomes uneven along the widthwise direction. On 
the other hand, it has been noticed that the drive roll can be solely 
mounted because of its motor-containing type, and the present invention 
has been worked out by finding out the fact that it is only necessary to 
incline the drive roll along the inclined bobbin holder. More 
particularly, the present invention provides a way of mounting a drive 
roll in a high speed winder, in which a drive roll bracket for holding a 
drive roll is pivotally supported by a pivot whose axis is an intersection 
line between a vertical plane equally dividing a distance between opposite 
remote end surface of a wound thread package and a horizontal plane that 
is tangential to a bottom surface of the drive roll or a horizontal plane 
in the proximity thereof, and a press contact force between said drive 
roll and the bobbin holder shaft or wound thread ball is applied entirely 
by the intermediary of said pivot. 
The principles of the invention will be further discussed with reference to 
the drawing wherein a preferred embodiment is shown. The specifics 
illustrated in the drawing are intended to exemplify, rather than limit, 
aspects of the invention as defined in the claims.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT 
Explaining now one preferred embodiment of the invention illustrated in the 
drawings, FIG. 4 is a fragmentary longitudinal cross-sectional view of a 
high speed winder showing one preferred embodiment of the present 
invention, and FIG. 5 is a fragmentary transverse cross-sectional view of 
the same. In these figures, a drive roll 10 is a motor-containing type of 
roll, which is rotatably supported from a drive roll bracket 11. The drive 
roll bracket 11 is rockably coupled to a support arm 20 via a pivot 19. 
The pivot 19 has its axis along an intersection line between a vertical 
plane equally dividing a distance between opposite remote end surface of 
the wound thread package 18 and a horizontal plane that is tangential to a 
bottom surface of the drive roll 10. The support arm 20 is fixedly secured 
to a slider 12, so that it can slide vertically along a guiderail 21. 
Accordingly, if a press contact force is applied to the slider 12 with 
publicly-known means, then the drive roll 10 makes contact under pressure 
with the surface of the bobbin holder 13 or wound thread package 18 at a 
predetermined press contact force, so that a torque generated by a motor 
(not shown) contained within the drive roll can be transmitted to a bobbin 
(not shown) that is tightly secured to and held by the outer circumference 
of the bobbin holder or to a wound thread package thereon. The bobbin 
holder 13 is integrally formed with the bobbin holder shaft 14, which is 
rotatably supported by the bearings 17 which are in turn resiliently 
supported from a frame 15 via springs 16. 
A spring 22 has its opposite ends fixedly secured to a drive roll bracket 
11 and a support arm 20, and it serves to compensate for unbalance of the 
weight of the drive roll 10 and the drive roll bracket 11 on the opposite, 
left and right sides with respect to the pivot 19. 
Explaining now the operation, if a predetermined press contact force P is 
applied the slider 12 with publicly-known means, then said press contact 
force P is transmitted to the drive roll bracket 11 via the support arm 20 
and the pivot 19, and eventually this is converted to the forces applied 
to the holding portions a and b of the drive roll 10 at its opposite ends. 
Owing to these forces, the drive roll 10 makes contact under pressure with 
the bobbin or the wound thread package 18, and since the pivot is 
positioned at a point equally dividing a distance between the opposite 
remote ends of the wound thread package, the press contact force applied 
to the wound thread package is uniform on the left and right sides of the 
pivot 19 regardless of the positions of said holding portions a and b. 
More particularly, paying attention to the press contact reaction force 
which is applied to the drive roll, if it is not uniform on the left and 
right sides, then the reaction force moments M of the left and right 
portions with respect to the pivot 19 are different, so that the drive 
roll 10 will be inclined up to such angle that the reaction force moments 
on the left and right sides become equal, and in this way the drive roll 
is balanced at an inclination that is identical to the inclination of the 
bobbin holder 13. However, it is to be noted that such balancing can occur 
only in case that the unbalance of weight of the drive roll 10 and the 
drive roll bracket 11 on the left and right sides with repect to the pivot 
19 has been offset by the spring 22, and that it is necessary to minimize 
the amount of unbalance of weight of the drive roll 10 and the drive roll 
bracket 11 on the left and right sides with respect to the pivot 19. 
In other words, if the unbalance is large, then the spring 22 for 
offsetting the unbalance becomes a strong one, and with such a strong 
spring, the spring force caused by compression or elongation of the spring 
when the drive roll bracket 11 is inclined becomes relatively large, so 
that uniformity of the press contact force is lost. In addition, it is 
necessary to dispose the bobbin holder shaft 14 and the drive roll 10 
within the same vertical plane, and this is for the purpose of limiting 
the inclination of the bobbin holder 13 and the drive roll 10 to within a 
vertical plane so as to match with the direction of the pivot 19. 
Further, in case that the weight of the drive roll 1 is light and its 
length is short, and also that there is a fear that rocking vibration of 
the drive roll 1 about the pivot may be caused by unevenness of the wound 
threadpackage, then an effective damper could be provided between the 
drive roll bracket 11 and the support arm 20. It is a matter of course 
that such a modified construction does not contravene the spirit of the 
present invention. In the following Table 1, the practice, according to 
the present invention, and the heretofore known method for mounting a roll 
are compared with respect to a practical example, and from this table it 
is clear that the practice, according to the present invention, is a 
considerable improvement. 
TABLE 1 
______________________________________ 
Practice According to 
Prior Art Practice 
the Present Invention 
______________________________________ 
Winding speed 
3,500 m/Min. the same as the left 
Wound yarn PET 260d the same as the left 
(after wound) 
Winding tension 
80 g the same as the left 
Traverse angle 
7.degree. (deg) 
the same as the left 
Press contact 
8 kg the same as the left 
force 
Length of about 300 mm, the same as the left 
a wound single yarn wound 
thread package 
Bobbin outer 
89 mm the same as the left 
diameter 
State of At a wound Winding could be 
winding diameter of achieved without 
95-100 .phi., any problem up to 
crumbling a wound diameter 
arose at the of 230 .phi. or more. 
face of the 
wound thread 
package on the 
bearing side. 
Displacement of 
impossible lowered by about 1 mm 
the tip end of 
to measure 
the bobbin holder 
when wound to a 
large diameter 
Drive roll about 40 Hz about 20 Hz 
resonant point 
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As described in detail above, according to the present invention, what was 
impossible to wind at a high speed in the prior art becomes possible to 
wind, and also without extremely enhancing an accuracy in the vertical 
direction of the drive roll and the bobbin holder they can be 
automatically brought to a parallel state, so that the design and assembly 
of the apparatus becomes easy. In addition, according to the present 
invention, the press contact forces between the drive roll and the bobbin 
holder or the wound thread package are balanced so that the moments on the 
opposite sides of the pivot may become equal to each other, and since the 
wound thread package is symmetrical with respect to the pivot, the press 
contact forces are also equal to each other. Since the axis of the pivot 
is positioned in a horizontal plane that is tangential to the bottom 
surface of the drive roll or in a horizontal plane in the proximity 
thereof, the relative slip between the surface of the wound thread package 
and the surface of the drive roll when the bobbin holder and the drive 
roll are inclined in parallel to each other, is very small, so that the 
influence of the inclination affected to the wound thread package becomes 
negligibly small. In addition, the bobbin holder undergoes only a vertical 
force component and is thus inclined within a vertical plane, and the 
drive roll also is inclined within the vertical plane following the bobbin 
holder because of the fact that the pivot axis is perpendicular to the 
bobbin holder shaft and is located in a horizontal plane, so that the 
parallelism between the bobbin holder and the drive roll can be maintained 
regardless of the diameter of the wound thread package.