Yarn winding apparatus

A yarn winding apparatus is disclosed which comprises a spindle mounted for rotation about a fixed axis, and a slide which is mounted adjacent the spindle and which includes a traversing yarn guide and a contact roll for engaging the surface of the package being wound on the spindle. Also, the slide is movable in a radial direction with respect to the spindle, and so that the slide moves radially outwardly as the package builds. Further, biasing means is provided for biasing the slide toward the package during the winding operation. The biasing means comprises structurally simple components, and permits ready control of the biasing force during the entire winding operation.

BACKGROUND OF THE INVENTION 
The present invention relates to a yarn winding apparatus of the type 
comprising a winding spindle which is rotated about a fixed axis and which 
is adapted to coaxially mount a bobbin tube for receiving the yarn, and so 
as to form a wound package thereon. Also, the apparatus includes a yarn 
traversing mechanism which is mounted in a slide which is adapted to move 
radially away from the spindle as the package builds on the bobbin tube. 
Winding apparatus of the described type are known wherein the bobbin tube 
which is mounted on the spindle is rotatably driven by contact with a 
drive roll, note for example DE-OS No. 25 44 773 and U.S. Pat. No. 
4,106,710. In order to apply the necessary driving force to the surface of 
the package as the diameter increases, there is provided means for 
regulating the pressure of the contact roll against the surface of the 
package, and which includes a pneumatic control by which a nominal value 
can be determined. In most instances, the slide is vertically movable, but 
according to one of the embodiments of the above described patents, the 
traversing slide is horizontally movable and incudes similar contact 
pressure regulating means. In the case of a yarn winding apparatus having 
a surface driven winding spindle, the contact pressure between the contact 
roll and the package needs to be accurately controlled, so as to prevent 
the sensitive layers of yarn on the surface of the package from being 
damaged by too much slippage. However, in the case of directly driven 
winding spindles, it is not usually necessary to control the contact 
pressure for these functional reasons. 
Precision package winding apparatus are also known, in which the slide 
mounting the traversing mechanism is moved radially from the axis of the 
winding spindle, or along a circular arc about a fulcrum. The slide 
typically mounts a contact roll which is pressed against the surface of 
the package by for example a compensating weight, note U.S. Pat. No. 
3,480,218, or by a resilient biasing means, note DE-OS No. 2,937,600, or 
by a cylinder-piston drive, note U.S. Pat. No. 3,717,311. The contact 
pressure serves to dampen the fluctuations which result from the movement 
of the slide. In addition, it has been found that the package build is 
advantageously influenced, when the pressure between the contact roll of 
the slide and the package surface is distributed over the entire axial 
length of the package. 
It is accordingly an object of the present invention to provide a yarn 
winding apparatus of the described type and wherein the contact pressure 
between the contact roll supported in the slide and the surface of the 
package may be controlled by a relatively simple mechanical mechanism. 
It is also an object of the present invention to provide a yarn winding 
apparatus of the described type wherein the contact pressure can be 
selected and controlled in accordance with the winding conditions, and 
preferably in a manner so that the pressure decreases during the build of 
the package. 
SUMMARY OF THE INVENTION 
These and other objects and advantages of the present invention are 
achieved in the embodiments illustrated herein by the provision of a yarn 
winding apparatus which comprises a frame, a winding spindle mounted to 
the frame for rotation about a fixed axis, and a slide mounted to the 
frame adjacent the spindle and so as to permit radial movement with 
respect to the spindle axis. The slide mounts yarn traversing means which 
is adapted to traverse a yarn onto a bobbin tube mounted on the spindle to 
form a wound package, and the slide also mounts a contact roll which is 
disposed parallel to the winding spindle and which is adapted to contact 
the wound package and move the slide away from the spindle as the package 
builds. The apparatus further comprises drive means for rotating the 
spindle and traversing the yarn traversing means, and means for biasing 
the slide toward the spindle during the build of the package. 
In accordance with the present invention, the biasing means comprises an 
arm having one end pivotally connected to the slide at a pivot point, and 
an opposite free end. Also, a cam is mounted to the frame and includes a 
guide edge disposed transversely to the direction of movement of the slide 
and so as to engage the opposite free end of the arm during movement of 
the slide. Means is also provided for applying a force to the arm which 
tends to rotate the arm about the pivot point and into engagement with the 
cam, and such that a component of the force tends to move the slide toward 
the spindle during the build of the package. The magnitude of the 
component of force may be controlled by adjusting the magnitude of the 
force applying means, and/or selecting the orientation and outline of the 
guide edge. In the preferred embodiment, the force applying means 
comprises a spring extending between an attachment point on the slide and 
another attachment point on the arm. Also, the attachment point on at 
least one of the slide and the arm is adjustable to control the magnitude 
of the applied force. 
The present invention thus provides a constructionally simple arrangement 
for biasing the slide into contact with the package, and which is not 
susceptible to breakdown, and which is adjustable in numerous ways so as 
to vary the contact pressure between the contact roll on the slide and the 
package being formed. This adjustment may be achieved by means of the 
guide edge, the angle of inclination of which may be adjusted with respect 
to the direction of movement of the traversing slide, or by exchanging the 
cam for a cam having a differently curved guide edge, so that a guide edge 
which is optimally adapted to the particular winding operation may be 
selected. 
The ability to adjust the magnitude of the force applied by the biasing 
means has the advantage that the contact pressure between the contact roll 
and the package can be varied while using the same structural members, 
since the same structural members can be selectively positioned to exert 
different levels of force on the slide, with the force thereby being 
adapted to the particular winding conditions and desired results.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring more particularly to the drawings, FIG. 1 illustrates a yarn 
winding apparatus in accordance with the present invention, and which 
includes a vertical housing plate 1 which comprises a portion of the frame 
of the apparatus, together with a winding spindle 3 which coaxially mounts 
a bobbin tube having a package 2 wound thereon. The spindle 3 is rotatably 
driven by a motor 4, and the yarn 12 advances at a substantially uniform 
speed over the stationary yarn guides 5 and 6, as well as over a 
compensating roll 29 which is rotatably supported on the arm 7. The yarn 
12 is thus wound onto the package on the spindle 3 under a substantially 
uniform tension. 
The apparatus further comprises a slide 11 which is mounted to the plate 1 
of the frame adjacent the spindle and so as to permit radial movement with 
respect to the axis of the spindle and along a generally horizontal 
direction. More particularly, the slide 11 includes a support 13, which is 
slideable along the guide rods 14 which extend in a horizontal direction 
as best seen in FIG. 2. The slide 11 mounts a yarn traversing guide 9 
which serves to reciprocate the yarn 12 in the axial direction of the 
package 2, and the guide 9 is guided in a straight slot in the slide 11, 
and is driven by a cross spiraled roll 10 which is also mounted in the 
slide 11, note FIG. 2. The slide 11 further includes a contact roll 28 
which is disposed parallel to the axis of the winding spindle and so as to 
contact the surface of the package 2 and thereby support the slide at a 
predetermined distance with respect to the package. As a result, the 
distance between the traversing guide 9 and the package remains constant, 
since the support 13 which carries the slide 11 is moved away from the 
circumference of the package in a straight line along the fixed guide rods 
14. 
FIG. 2 also illustrates the drive means for rotating the spindle 3 and for 
traversing the yarn guide 9. As will become apparent, the illustrated 
drive means is of the precision winding type, in that the drive means 
provides an operative, fixed connection between the winding spindle and 
the cross spiraled roll 10 of the yarn traversing means. More 
particularly, the drive means includes the motor 4, which preferably 
comprises a speed controllable asynchronous motor, which is directly 
connected to the winding spindle 3 via a toothed belt 32 and pulleys 31 
and 33. From the winding spindle 3, the drive is transmitted to the cross 
spiraled roll 10, via an intermediate transmission which not only 
rotatably interconnects the roll 10 to the motor 4 during the entire 
winding operation, but in addition permits the support 13 and the slide 11 
to move along the guide rods 14 away from the package as the diameter of 
the package increases. This intermediate transmission includes the toothed 
belts 19 and 20, which are mounted respectively on the belt pulley 16 on 
the spindle 3 and the pulley 17 which is fixed on the shaft of the roll 
10. The shaft 30 for the intermediate joined pulleys 18 and 26 is attached 
to a pivoting lever 23, which in turn is rotatably supported on the 
spindle 3 and is longitudinally adjustable by a sliding connection 24. In 
addition, the shaft 30 is supported on a supporting lever 22, which is 
also longitudinally adjustable by a slide connection 25 and is rotatable 
on the shaft of the roll 10. 
A transformer 8 is provided for controlling the speed of the motor 4 for 
the winding spindle 3. A control signal which is a function of the yarn 
tension as measured by the deflection of the arm 7, is delivered to the 
transformer and so as to control the speed of the motor 4 in a 
conventional manner. FIG. 2 also illustrates the means for biasing the 
slide 11 toward the spindle during the build of the package, and which is 
indicated generally at 15. 
FIGS. 3 and 4 illustrate in more detail the means 15 for biasing the slide 
toward the spindle. In these views, the drive members between the motor 
and spindle 3 and the roll 10 are omitted for clarity of illustration. 
FIG. 3 illustrates one end position of the reciprocating slide 11, and 
wherein the package formed on the spindle 3 has its smallest diameter. 
FIG. 4 on the other hand shows the position of the slide 11 when the 
diameter of the package has reached its maximum. 
The biasing means 15 comprises an arm 50, which has one end pivotally 
connected to the slide at a pivot point 51, with the pivotal axis 
extending transversely, and preferably perpendicular to the direction of 
movement of the slide. The arm 50 includes an opposite free end which 
rotatably supports a roller 52. Also, there is provided a cam 54 which is 
mounted to the frame of the apparatus and which includes a guide edge 54a 
disposed transversely to the direction of movement of the slide and so as 
to engage the roller 52 at the free end of the arm 50. A force applying 
means is also provided which applies a force to the arm 50 which tends to 
rotate the arm about the pivot point 51 and so that the roller 52 is 
pressed into engagement with the guide edge 54a of the cam 54. Thus a 
component of the force tends to move the slide toward the spindle during 
the build of the package, and the magnitude of this component of force is 
controlled by the magnitude of the force applying member and the 
orientation and outline of the guide edge 54a of the cam. 
In the illustrated embodiment, the force applying member comprises a spring 
53 which extends between an attachment point 55 on the arm and an opposite 
attachment point positioned on a mounting plate 56, which in turn is 
mounted to the support 13 of the slide 11. The plate 56 is provided with 
several teeth or notches 57, so as to permit adjustment of the attachment 
point of the spring 53 to the slide. Similarly, a number of attachment 
pins 55 are mounted along the length of the arm 50, which are equally 
spaced apart from each other, and such that the end of the spring may be 
attached to a selected one of the pins 55 to thereby vary the magnitude of 
its force. 
The cam 54 is adjustably mounted to the frame of the apparatus, by means of 
a rod 59 which is fixed to the frame, and a pair of clamping devices 58 
which are secured to the cam 54. Thus, the elevation of the cam may be 
varied. The configuration of the guide edge 54a of the cam 54 is, in the 
most simple case, a straight line. However, the guide edge may also be 
curved as illustrated, with the curve being empirically determined from 
the winding parameters. Also, the guide edge may be completely changed, by 
exchanging the cam 54 for another cam having the desired configuration. 
FIG. 4 illustrates the slide 13 at the end of the winding cycle, and 
wherein the slide has moved along the guide rods 14 to its extreme end 
position. In this position, the roller 52 has moved upwardly along the 
guide edge 54a of the cam 54 to its highest position. While the spring 53 
is, in this end position, substantially more lengthened and tensioned than 
in FIG. 3, the force component acting against the slide 11 may be actually 
less than in the position of FIG. 3, by reason of the changed angular 
position of the arm 50. Thus the force component acting against the 
package may be selectively controlled by the curvature of the guide edge 
54a. As a result of the curvature of the guide edge, the contact pressure 
against the package may even decrease to a zero value during the winding 
operation. 
FIG. 5 illustrates a different embodiment of the invention, with the slide 
11 being illustrated at the start of the winding cycle. In this 
embodiment, the cam 54' is pivotally mounted to the frame at 60, and the 
opposite free end of the cam 54' includes a clamping device 62 which is 
movable along the arcuate slot 61, with the slot 61 representing a segment 
of a circle having its center at 60. The clamping device 62 is designed to 
secure the free end of the cam 54' in a selected pivotal position. In so 
adjusting the angular position of the cam 54', the angle alpha between the 
cam 54' and the straight guide rods 14 may be selected so that the 
component of the force which is operative on the slide is adjustable in 
magnitude and direction, and between limits which can be selected. 
In the drawings and specification, there have been set forth preferred 
embodiments of the invention, and although specific terms are employed, 
they are used in a generic and descriptive sense only, and not for 
purposes of limitation.