Yarn traversing apparatus

The yarn traversing guide is slidably mounted within a pair of slats disposed across the face of the drum housing for reciprocating motion. Each slat is provided with a rigid center section and two spring-elastically deflectable end sections. The end sections deflect to a limited degree during reversing of the high speed traversing guide without impairing the life of the traversing guide.

This invention relates to a yarn traversing apparatus. 
As is known, various types of yarn traversing devices have been used for 
traversing or reciprocating a yarn or thread, for example, for winding on 
winding machines. Generally, these devices employ a traversing guide which 
meshes via a guiding shoe with an endless cam groove of a rotatably 
mounted drum as well as a gliding member which is guided in the direction 
of the traversing motion between two parallel rails. These parts are 
fixed, for example, with respect to a housing of the reciprocating drum. 
For example, as described in Swiss Pat. No. 447,902, one particular yarn 
traversing device has a cam groove in the sleeve of a rotatable drum which 
consists of two helical grooves. The helical increments of the grooves 
extend in opposite directions and merge at their respective ends via an 
arc-shaped curve in such a manner that the yarn traversing guide is 
reciprocated to and fro by the drum in the direction of the traversing 
motion parallel to the axis of a bobbin tube onto which the yarn is wound. 
A guiding shoe of the yarn guide which is guided by the groove is of 
generally longitudinally extended shape. Thus, the shoe can pass the cross 
over points of the two grooves safely and without change of direction. 
Further, the yarn guide is provided with a rhomboid gliding member when is 
guided between the side surfaces of the two guide rails. In this 
arrangement, the gliding member can follow the change of position of the 
shoe at the return points of the traversing motion by tilting from one 
gliding position into the other. Further, the yarn traversing guide is 
provided with an intermediate member which is arranged between the shoe 
and the gliding member. This intermediate member fits exactly into the 
clearance between the guide rails and the drum and tangentially contacts 
the surface of the drum. This intermediate member is provided in order to 
prevent a tilting motion of the yarn traversing guide in the zone of the 
return points where the arc-shaped groove is enlarged. 
However, practical experience has shown that an intermediate member of this 
type is too small to prevent a tilting motion of the yarn traversing 
guide. As a result, smoothness of the run and the wear life of the yarn 
traversing guide are not satisfactory. 
As described in German DT-GM No. 6,900,984 (corresponding to U.S. Pat. No. 
3,664,596) another yarn traversing apparatus which is intended to overcome 
these above disadvantages, has a gliding member meshing with two guide 
grooves which extend in mutually parallel relation to the direction of the 
traversing motion in the guide rails. Further, the gliding member is 
disposed to be tiltable in the grooves about its height axis so that 
tilting of the yarn traversing guide is avoided. However, this apparatus 
does not obtain the improvement desired. In particular, in the zone of the 
return points, the yarn traversing guide must take up extremely high 
tilting momentums, deceleration forces and acceleration forces. Thus, 
impacts and relatively excessive heating due to the greater friction 
forces are generated such that the smoothness of the run and the wear life 
of the traversing guide remain unsatisfactory. 
Accordingly, it is an object of the invention to provide a yarn traversing 
apparatus which is capable of high traversing speeds. 
It is another object of the invention to provide a yarn traversing 
apparatus which is able to operate at traversing speeds of 800 to 1,000 
per minute. 
It is another object of the invention to provide a yarn traversing guide 
which is able to run extremely smoothly at high traversing speeds. 
It is another object of the invention to provide a yarn traversing guide of 
relatively long life for use at high speeds. 
Briefly, the invention provides an apparatus for traversing a yarn across a 
given path on a winding machine at relatively high speeds, e.g., of 800 to 
1,000 miles per minute. This apparatus comprises a housing, a drum which 
is rotatably mounted in the housing, a pair of parallel rails fixed to the 
housing and a traversing guide for traversing a yarn in the given path. 
The drum is provided with an endless cam groove in a surface thereof while 
each of the rails has a guide slat containing a rigid center section and a 
pair of end sections. In addition, each end section is elastically 
deflectable to a limited degree in a direction at right angles relative to 
the path in which the yarn is traversed. The traversing guide includes a 
gliding shoe which is slidably disposed in the cam groove of the drum and 
a gliding member which projects from the housing and has a pair of grooves 
receiving the guide rails therein for movement parallel to the yarn 
traversing path. 
Surprisingly, the wear life of the yarn traversing guide achieves time 
durations heretofore unobtainable. A particularly long wear life of the 
yarn traversing guide can be obtained when each guide slat is rigidly 
connected to a rail in the center section and is disposed in a groove of 
the rail in each end section in spaced relation to the rail. The end 
sections of the guide slat are deflectable at a bias to the groove. Each 
guide slat, which may consist of a spring steel strip, can be adhesively 
bonded to the center section of a guide rail and may be additionally 
secured by set screws. 
One particular arrangement which has proven to be particularly advantageous 
is one in which the guide slat is deflectable over a zone corresponding to 
one tenth of the length of the traversing width and is spaced on three 
sides from the rail at a distance equal to 0.2 millimeters. 
In another embodiment, each guide slat is integral with a respective rail 
to form a one piece member. In this embodiment, the guide rail is formed 
with an elongated opening at each end to define a guide slat end section, 
or, in the alternative, each guide rail has a recess at each end to define 
a guide slat end section.

Referring to FIG. 1, the yarn traversing apparatus includes a drum 1 which 
is rotatably mounted in a housing 2. As shown, a pair of guide rails 3, 4 
is fixed to the housing 2 by means of screws 5, 6, which pass through 
bores 19 in the rails 3, 4. Each rail 3, 4 has a guide slat 7, 8 fixedly 
secured thereon at the parallel, mutually facing face sides of the rails 
3, 4. As shown in FIGS. 3, 4, each slat (only one of which is shown for 
simplicity) contains a rigid center section and a pair of end sections 
which are disposed in spaced relation on three sides to the guide rail 4. 
As indicated in FIG. 5, the center section of each guide rail 3, 4 is 
provided with a groove 16 of rectangular cross section to receive the 
center section of the guide slat 8. In this regard, the cross section of 
the guide slat 8 corresponds to the cross section of the groove 16. In 
addition, the center section of the slat 8 is adhesively bonded in the 
groove 16, for example, by means of a two-component adhesive. In order to 
further secure the slat 8 in place, set screws 31 can also be threaded 
into the guide rail 4 within the center section. 
As shown in FIG. 6, the groove 16 is enlarged in the end sections of the 
guide rail 4 such that clearances a, b, c are formed between the slat 8 
and the rail 4. A clearance of 0.2 millimeters is very suitable on each of 
the three sides of the slat 8 from the guide rail 4. As such, the end 
sections of the guide slat 8 extend freely into the enlarged groove space. 
This allows each end section to be elastically deflectable to a limited 
degree in a direction at right angles relative to a yarn traversing path. 
The horizontal and vertical deflection of the end sections is indicated by 
the use of double arrows 17, 18, respectively in FIG. 7. 
Referring to FIGS. 1 and 2, a yarn traversing guide 10 is disposed on the 
drum 1 and guided between the slats 7, 8. As indicated, the yarn 
traversing guide 10 contains a gliding shoe 11 which is slidably disposed 
in a cam groove, for example, an endless helical groove 12 in the drum 1. 
In addition, the yarn traversing guide 10, which preferably consists of a 
plastic material, carries a gliding member 9 which projects from the 
housing 2. The gliding member 9 has guide grooves 21, 22 which receive the 
guide slats 7, 8 respectively therein. Still further, the traversing guide 
10 has a yarn guide eyelet 13 made of ceramic material inserted in the end 
of the gliding member 9. This eyelet 13 guides and traverses a yarn 14 
before the yarn 14 is wound onto a take-up bobbin package 15 of a winding 
machine (not shown). 
Referring to FIG, 2, the gliding member 9 is formed with pairs of mutually 
parallel side faces 23, 26 and 24, 25, respectively in which the grooves 
21, 22 are formed. As indicated, the bottom surfaces of the grooves 21, 22 
are in the shape of a hemi-cylinder and extend parallel to the side faces 
23-26 in such a manner that a cross section through the groove bottom 
surfaces 27, 28, 29, 30, as well as a section through the sides faces 
23-26 is in the shape of a rhomboid, the points of which are cut off. 
During operation, the yarn traversing guide 10 is driven by the rotation of 
the groove drum 1 via the gliding shoe 11. Thus, the traversing guide 10 
is guided to and fro in the helical groove 12 at relatively high speed 
over a traversing width L (FIG. 3) parallel to the path of the traversing 
yarn. The yarn traversing guide 10 is further guided on the guide slats 7, 
8 in the direction of the traversing motion. To this end, the guide slats 
7, 8 mesh with the grooves 21, 22 of the gliding member 9 mainly on the 
groove side surfaces; sufficient clearance being provided between the 
hemi-cylindrical groove bottom surfaces 27-30 and the hemi-cylindrical 
face sides of the guide slats 7, 8. The side surfaces 23-26 of the gliding 
member 9 are not guided as a sufficient clearance is provided between 
these sides and the face sides of the guide rails 3, 4. At the return 
points, the gliding member 9 switches over from one set of parallel side 
surfaces and groove bottom surfaces to the other set, e.g., from the side 
surfaces 24, 25 and the groove bottom surfaces 28, 29 to the other 
mutually parallel side surfaces 23, 26 and the groove bottom surfaces 27, 
30. In this way, either the surfaces 24, 25, 28, 29 or the surfaces 23, 
26, 27, 30 are guided in parallel to the guide slats 7, 8 and the guide 
rails 3, 4. Switching over of the gliding member 9, and thus of the yarn 
traversing guide 10, is effected by the change of direction of the gliding 
shoe 11 in the helical groove 12; the gliding shoe 11 being deflected at 
the return points of the helical groove 12. 
Since the guide slats 7, 8 are rigidly connected to the guide rails 3, 4 in 
the center section while being deflectable to a limited degree in the end 
sections, the yarn traversing guide 10 may also recede slightly in the 
zone of the return points of the yarn traversing guide. That is, in the 
zone of the return points, the yarn traversing guide 10 is still guided 
via the gliding member 9 on the slats 7, 8 and by the shoe 11 in the 
helical groove 12. The groove 12 is dimensioned to be slightly larger in 
the zone of the return points that the shoe 11. 
Surprisingly, it has been found that an apparatus of the above construction 
in which the yarn traversing guide 10 can have a limited deflection and 
tilt, the run of the yarn traversing guide 10 is extremely smooth. The 
large tilting momentums, deceleration forces and acceleration forces and 
the friction forces generated thereby are distributed onto the guide slats 
7, 8 and the helical groove 12 in such a manner that the stress at a 
single point of the traversing guide is relatively small. Also, a 
deflection in a direction at right angles to the guide slat 7, 8 caused by 
the greater friction forces at the return point, effects a reduction of 
the stress peaks in the gliding shoe 11. 
Tests using the described apparatus show that the yarn traversing guide 10 
has a wear life two to three times longer than conventional structures. It 
has also proven to be of advantage if the end section of each guide slat 
7, 8 is deflectable over a length equal to one tenth the traversing width 
L and if the slats 7, 8 are made of spring steel strips. 
Referring to FIG. 7, the above-described apparatus may also be employed 
with a drum housing 2 wherein the guide rails 4 (only one of which is 
shown for purposes of simplicity) are mounted at an angle. In such a case, 
the guide slat 8 is mounted in an inclined position within a guide rail. 
Alternatively, instead of forming the slats separately from the guide 
rails, the slat may be formed in an integral manner with the guide rail. 
For example, as shown in FIGS. 8 and 10, a guide rail 32 may be formed 
with an elongated opening 33 at each end section so as to define a 
deflectable end section of a slat 34 adjacent thereto. As shown in FIG. 8, 
the guide rail 32 may be tapered gradually in the direction towards the 
slat 34 or, as shown in FIG. 9, the guide rail 32 may be formed in a 
step-wise manner with the slat 34 formed in the thinner section. 
Referring to FIG. 11, a one-piece guide rail 35 may alternatively be formed 
with a recess 36 in each end section to form the end sections of slats 37. 
The slats 34, 37 which are integrally formed with the rail (32, 35) are of 
such small dimensions as to be deflected in the vertical and lateral 
directions as viewed. Because of the one-piece construction, no fixation 
means are required between the slat and guide rail.