US3659796A

US3659796A - Yarn winding apparatus

Info

Publication number: US3659796A
Application number: US57220A
Authority: US
Inventors: Erich Bucher; Alfred Maldener
Original assignee: Zinser Textilmaschinen GmbH
Current assignee: Oerlikon Textile GmbH and Co KG
Priority date: 1969-07-22
Filing date: 1970-07-22
Publication date: 1972-05-02
Anticipated expiration: 1989-05-02
Also published as: GB1317933A; CH508547A; FR2030862A5; DE1937178A1

Abstract

In a yarn winding apparatus the yarn, to effect its deposition on a cross-coil type yarn package, is caused to reciprocate transversally to its direction of feed by means of rotating contour discs. In order to eliminate the formation of circumferential beads adjacent the edges of the yarn package, the winding apparatus comprises means for cyclically displacing said contour discs in a direction normal to their axis of rotation for periodically reducing the amplitude of the transversal reciprocation of the yarn during the winding operation.

Description

United States Patent Bucher et al.

[54] YARN WINDING APPARATUS [72] inventors: Erich Bucher; Alfred Maldener, both of Goppingen, Germany [73] Assignee: Zinser-Textilmaschlnen sbach, Germany [22] Filed: July 22, 1970 [2]] Appl. No.: 57,220

Gmbl-l, Eber- [30] Foreign Application Priority Date July 22, 1969 Germany ..P 19 37 178.9

[52] U.S. Cl i.242/l8.i, 242/43 [51 1 int. Cl. a ..B65h 54/28, B65h 54/38 [58] Field of Search ..242/l8.1, 18 DD, 43 A, 43 R [56] References Cited UNITED STATES PATENTS 1/1970 Torsellini et a1. ..242/18.1 X 9/1968 Mattingly ..242/l8.l X

[ 1 May2, 1972 3,527,421 9/1970 Shippers et al ..242/1 8 DD FOREIGN PATENTS OR APPLICATIONS 1,495,119 8/1967 France ..242/18.1 679,838 8/1939 Germany ..242/43 A 690,941 5/1940 Germany ..242/43 A 453,155 5/1968 Switzerland ..242/43 A Primary Examiner-Stanley N. Gilreath Attorney-Edwin E. Craig [57] ABSTRACT In a yarn winding apparatus the yarn, to effect its deposition on a cross-coil type yarn package, is caused to reciprocate transversally to its direction of feed by means of rotating contour discs. in order to eliminate the formation of circumferential beads adjacent the edges of the yarn package, the winding apparatus comprises means for cyclically displacing said contour discs in a direction normal to their axis of rotation for periodically reducing the amplitude of the transversai reciprocation of the yarn during the winding operation.

12 Claims, 8 Drawing Figures Patented May 2, 1972 3,659,796

3 Sheets-Sheet 1 IN V EN TORS Patented May 2, 1972 3 Sheets-Sheet 15 BACKGROUND OF THE INVENTION This invention relates to a yarn winding apparatus wherein the individual yarn is continuously reciprocated, between two inversion points, transversally to its direction of feed, for example, by means of at least two contour discs which are rotatable about parallel axes. More particularly, the invention relates to the winding of yarn on a cylindrical bobbin to form a cross-coil type wound package having a cylindrical configuration. It is to be understood, however, that the invention may find application, for example, in apparatuses which cross-wind the yarn onto a conical bobbin to form a conical wound package.

The term yam" is given the broadest possible meaning. It includes textile yarns of any type, such as threads, twisted yarns, etc., and also endless synthetic yarns or the like.

During the cross-coil winding in known winding apparatus of the aforenoted art, circumferential bulges or beads are formed at both ends of the yarn package, because the point of contact which is defined between the incoming yarn and the yarn package and which determines the position of the yarn on the coil, does not exactly follow at the inversion points the yarn guidance effected by the contour discs. Such beads are disadvantageous, because they may substantially interfere with the further processing of the cross coils. For example, they may render the axial drawing from the coil difficult, or, during dyeing processes, they may cause non-unifonn coloring, etc. The formation of heads is particularly disadvantageous in the case of sensitive, very thin yarns, such as endless synthetic yarns.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide an improved yarn winding apparatus of the above type, wherein the aforenoted formation of beads is at least substantially eliminated so that extremely sensitive, very thin yarns may be wound with high speed to form cross-coil type yarn packages.

Briefly stated, according to the invention the yarn winding apparatus comprises means to reduce, from time to time during the winding operation, the amplitude of the transversal yarn stroke. More particularly, the rotating contour discs, cooperating with at least one parallel extending yarn guide, are displaceable, during the winding operation, in a direction normal to their axis of rotation by means of a control device for varying the amplitude of the transversal yarn stroke. By means of a proper alteration of the magnitude of the transversal yarn stroke during the winding process, the formation of beads at the edges of the cross coils is either reduced to such an extent as to no longer present any inconvenience, or is eliminated altogether.

The invention will be better understood, as well as further objects and advantages of the invention will become more apparent, from the ensuing detailed specification of a preferred, although exemplary, embodiment of the invention taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational view of the preferred embodiment;

FIG. 2 is a fragmentary front elevational view of the same embodiment (some details shown in FIG. 1 are omitted for the sake of clarity);

FIG. 3 is an enlarged fragmentary top plan view of the same embodiment (some details shown in FIG. 1 are omitted for the sake of clarity);

FIG. 4 is an enlarged and more detailed sectional view of some components shown in FIG. 2;

FIG. 5 is a fragmentary sectional view along line V-V of FIG. 4;

FIG. 6 is a schematic top plan view of two pairs of contour discs used in the structure shown in FIGS. 1-5;

FIG. 7 is an elevational view of the components shown in FIG. 6; and

FIG. 8 is a diagram illustrating the course of laying the yarn on a cross-coil type package by means of the preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-7 illustrate a single winding station of a winding apparatus according to the preferred embodiment. It is to be understood that the winding apparatus usually includes a plurality of winding stations disposed in the line of view of FIG. 1.

Turning now to FIG. 1, the winding apparatus includes a machine frame 10, a gear casing 11 which extends substantially along the entire length of the apparatus and in which there is disposed a main driving shaft 12 rotated by a main driving motor, not shown. Shaft 12 supplies the driving power to the individual winding stations 14, and the control device 13 which serves for displacing the contour discs 16-19 that cause the transversal motion of the yarn 15. As best shown in FIGS. 4-6, the contour discs 16-19 form two pairs, one consisting of

coplanar discs

16, 17, the other consisting of

coplanar discs

18, 19. The two discs constituting one pair are oriented at 180 with respect to one another and revolve as a unit. The two disc pairs are arranged in adjacent parallel overlapping planes so that they may rotate without interfering with one another. The longitudinal axes 22 of each disc pair are disposed at with respect to one another. The contour discs l6, 17 are mounted on shaft 21, while the

contour discs

18, 19 are secured to shaft 20. The contour discs within each disc pair are radially movable simultaneously towards or away from their associated

shaft

20 or 21 as indicated by arrows H in FIG. 6, and as will be discussed in more detail hereinafter. The

drive shafts

20, 21 are supported for rotation in the bearing boxes 23. As seen in FIGS. 1 and 2, the lower end of the

drive shafts

20, 21 carry the

contour discs

18, 19 and 16, 17, respectively, whereas at their upper free ends there is secured a sprocket gear 24. Each gear 24 is driven by means of a sprocket chain 25 from a gear 26 disposed on the top of the gear casing 11. The gears 26 are driven with a constant rpm by means of a gear train (not shown) from the main drive shaft 12, so that the

drive shafts

20, 21 of the contour discs 16-19 also rotate with a constant speed.

The yarn 15 to be wound by the winding apparatus is taken from yarn cops inserted on holders (neither shown) which, in turn, are aimed to the machine frame, and is guided along the path indicated by dash-dot lines in FIG. 1 to a cylindrical drum 27. The latter is disposed immediately below the contour discs and drives by friction the cross coil 29 held by a bobbin 30 and urged against the drum 27 by spring means. The length dimension of the cross coil 29 extends parallel to the plane of rotation of contour discs 16-19. The drum 27 may be driven by means (not shown) from the main drive shaft 12 with the same rpm as the

drive shafts

20, 21 of the contour discs 16-19. The bobbin 30 is held on an arm 31 in such a manner that the bobbin axis is disposed parallel to the axis of the drum 27. The arm 31 is pivotally held on the machine frame 10 and is springbiased in the direction of arrow B for urging the cross coil 29 into frictional contact with drum 27.

The cylindrical surface of the drum 27 is provided at two diametrically and axially opposed locations with axially outwardly pointing V-shaped grooves 33, the function of which will become more apparent as the specification progresses.

To each

drive shaft

20, 21, as shown in FIGS. 4 and 5, there is affixed a hub 36 to which there are fixedly secured two oppositely oriented guide plates 34 extending parallel to the rotational axis of the drum 27 and normal to the axis of rotation of the contour discs.

Each contour disc is provided with a shackle plate 35 designed in such a manner that it receives in a form-locking manner a guide plate 34. To ensure an accurate linear guidance of each contour disc normal to its axis of rotation in the direction of arrow C, each guide plate 34 is provided with a pair of parallel extending linear ribs 54 projecting into complemental slots 55 cut into the shackle plate 35 (FIG. 5). At each free end the guide plates 34 are provided with an integral enlargement 34' which, Cooperating with the terminus of the associated shackle plate 35, serves as an abutment to determine the outermost position of the contour discs. The innermost position of the contour discs, on the other hand, is determined by the abutting engagement between the terminus of each rib 54 and the end of each slot 55.

For maintaining the contour discs in their predetermined positions and in order to permit their displacement therefrom in a controlled manner, to each contour disc there is fixedly secured a pin-like abutment 37 which extends parallel to the axis of rotation of the contour disc and projects with its skewed free end in a conical recess 39 of a setting ring 40. The latter, in turn, is axially displaceably held on the hub 36 and rotates with the drive shaft. The abutment 37 is continuously pressed against the internal wall of the conical recess 39 by means of a compression spring 41 and also, during operation, by means of the centrifugal forces exerted on the contour discs. In FIG. 4 the setting rings 40 are shown in their extreme withdrawn position and thus, the contour disc pairs controlled thereby are in their outermost positions (i.e. at their greatest radial distance from their respective drive shafts 20, 21) in which they cause a maximum transversal stroke of the yarn. When the setting rings 40 are displaced in the direction of arrow D, the contour discs 16-19 are displaced by virtue of the abutments 37 in the direction of their

respective drive shafts

20, 21 and correspondingly, the amplitude of the transversal yam stroke caused by the contour discs is decreased. It is noted that all four cooperating contour discs 16-19 (FIG. 6) perform simultaneous displacements of identical magnitude and that the shift of two contour discs associated with the same drive shaft always occurs in opposite directions.

Each setting ring 40 is provided with an external circumferential groove 42 into which extend, with a small clearance, guide rollers 43 rotatably held by means of roller bearings. As seen in FIG. 4, the rotational axis of guide rollers 43 is normal to the axis of rotation of the contour discs and the rollers 43 themselves are so arranged that they may roll on the lateral internal wall face of the circumferential groove 40.

The guide rollers 43 associated with one setting ring 40 are held in a U-shaped yoke 44 which extends approximately over one-half of the circumference of the associated setting ring and which is secured to a bar 45 guided for linear movement by a sleeve 46 attached to the front side of the gear casing 23. Each bar 45 is biased by a compression spring in such a manner that it is pressed against a rocker arm 47 mounted on the top of the gear casing 11. All rocker arms 47 are keyed to a common oscillatable axle 49. The angular position of the latter is controlled by a contour wheel 50 to which there is pressed, by means of the aforenoted springs associated with bars 45, an additional rocker arm 51 affixed to the axle 49. The contour wheel 50 is keyed to a rotatably held shaft which is driven from the main drive shaft 12 by a step-down gear with an rpm that has a constant relation to the rpm of the

drive shafts

20, 21. it is noted that the rpm of the contour wheel 50 is generally substantially smaller than the rpm of the

drive shafts

20, 21 of the contour discs 16-19.

As may be observed in FIGS. 6 and 7, for the linear guidance of the transversal stroke motion of the yarn there are arranged between drive shafts and 21, parallel extending stationary yarn guides 56 and 57 disposed in alignment at either side of the contour disc assembly 16-19. Each

yarn guide

56, 57 is formed of two parallel bars such as 58, 59 constituting the yarn guide 57 (FIG. 6). The guide bars forming a yarn guide define a yarn guide slot 60, the height of which is slightly greater than the thickness of the yarn. The yam guide slots 60 are disposed in a plane containing the two axes of rotation of the drive shafts 20 and 21 (FIG. 6).

in order to simplify the driving means for the drive shafts, it is expedient to rotate all drive shafts in the same direction as indicated by the arrows B in FIG. 6.

i The working portions of the contour edges 61 which cooperate with the yarn and define the outline of the individual contour discs are so designed that the yarn, at constant rpm of the associated drive shaft, is moved with constant speed transversely to its direction of travel by the contour edges when the contour discs are in their normal position (preferably in their outermost position, that is, farthest from their associated

drive shaft

20, 21, respectively). Accordingly, the working contour edges 61 are at least substantially archimedean spirals related to the axis of rotation in the normal position of the contour discs. When the contour discs are not in their normal position, the transversal stroke speed of the yarn is no longer exactly constant which, however, is not a disturbing circumstance since these latter positions serve merely for the elimination of bead formation and further, the deviations are extremely small.

As best seen in FIG. 6, as the contour disc pairs 16, 17 and 18, 19 rotate counterclockwise, by virtue of the cooperation between the contour edges 61 of the contour discs 17 and 18 a guiding fork is formed which travels along slot 60 away from drive shaft 20 towards drive shaft 21. Then, by virtue of the cooperation between the contour edges 61 of the contour discs 16 and 18 a guiding fork is formed which travels along slot 60 away from drive shaft 21 towards drive shaft 20. Thereafter, the contour edges 61 of

contour discs

16, 19 and finally those of

contour discs

17, 19 form the traveling guiding fork. By virtue of the afore-described cooperation between the contour discs, the yarn 15, which extends transversally through the yarn guides 56, 57 (HG. 7), is moved continuously to and fro in slot 60 between the

drive shafts

20 and 21. It is thus seen that the yarn executes one full to-and-fro reciprocation for every 180 rotation of the disc drive shafts and each contour disc guides the yarn through at least 180 of its transversal motion which corresponds to a turn of the drive shafts. In order to permit a displacement of the contour discs in the direction of arrows H, the discs forming one pair are, at diagonally opposite end ranges, out to form straight edges 75. Also, immediately adjacent the drive shafts they are provided with bays 75'. Along ranges 75 and 75' the yarn does not engage the contour discs since the axes of the drive shafts are arranged at a distance from the inversion points 65. In FIG. 6 the contour discs 16-19 are shown in their outermost position in which they impart a maximum transversal stroke to the yarn. As it is seen, between two contour discs of a contour disc pair there is provided sufficient clearance to permit displacement of the contour discs in the direction of arrows H by shifting the setting ring 40 towards the associated contour discs.

The feature of providing two oppositely oriented contour discs on a drive shaft results in a balanced rotary structure and ensures a superior yarn guidance. It is to be understood, however, that each disc drive shaft may be associated with a single contour disc or more than two contour discs.

The number of disc drive shafts is identical to the number of the winding stations less one, since each contour disc pair disposed between the two external contour disc pairs simultaneously serves two adjacent winding stations in a manner known and obvious by itself. The longitudinal axes of adjacent contour disc pairs are at all times displaced at 90 with respect to one another.

OPERATION OF THE PREFERRED EMBODIMENT As the drum 27 is driven with a constant rpm, the yarn 15, taken from the yarn cop with constant speed, is reciprocated transversely to its direction of travel in the yarn guiding slots 60 by the contour discs 16-19 and, after being trained partially about the drum 27, is wound on cross-coil package 29. The length of the wound package 29 is determined by the maximum amplitude of the transversal yarn stroke effected by the contour discs when disposed in their outermost position. Under such conditions the yarn, in the vicinity of either edge of the package 29, and shortly before reaching the corresponding inversion point, drops into a groove 33 of the drum 27 associated with that inversion point. The groove 33 guides the yarn in such a manner that the laying of the yarn onto the package 29 follows the course shown in solid lines at 64 in FIG. 8. It is thus seen that in the vicinity of the inversion points 65, grooves 33 cause the yarn to be displaced with a constant speed transversely to its direction of travel up to the inversion point and thereafter, very abruptly, the yarn is caused to reverse its direction of transversal movement. In this manner a linear, zig-zag course results. It will be observed that the deposition of the yarn at the inversion points 65 proceeds in an acute angle. It is noted that without grooves 33 the deposition of the yarn at inversion points 65 would follow a rounded course.

Despite the provision of grooves 33, however, the bead formation at the edges of the cross-coil package cannot be normally avoided. In order to reduce or completely avoid the formation of such beads, the contour discs are cyclically displaced relative to their associated drive shafts, by means of the control device 13 which includes the contour wheel 50, the associated

rocker arms

47, 51, the stem 45 and the setting rings 40, for the purpose of varying the amplitude of the transversal yarn stroke. Each revolution of the contour wheel 50 corresponds to one cycle. In the presently described embodiment, the rpm of the contour wheel 50 is constant, so that the cycles are of identical duration and succeed one another without pause.

As long as the rocker arm 51, which determines the angular position of the shaft 49, engages the edge portion 67 of the contour wheel 50, which is the closest to the rotational axis thereof, the contour discs 16-19 are in their outermost position, thus causing a maximum transversal yarn stroke. As noted hereinbefore, under these conditions the yarn is guided in the range of the inversion points 65 by means of grooves 33 provided in the drum 27. As soon as the rocker arm 51 engages the cam-shaped circumferential range 68 of the contour wheel 50, the contour discs 16-19 are displaced inwardly towards one another. The exact shape of the contour wheel 50 may be determined by experimentation and is so designed that a bead formation is practically entirely eliminated. FIG. 1 shows an exemplary configuration of the contour wheel 50. By virtue of this configuration, in the initial phase, the inward motion of the contour discs 16-19 is relatively rapid. From position 69 on, however, the inward motion is slowed down substantially until it passes position 70 at which moment the smallest transversal yarn stroke is obtained. Thereafter, the contour discs 16-19 are guided symmetrically outwardly.

The initial phase of the inward motion of the contour discs 16-19 has no effect on the transversal yarn stroke as long as the yarn may drop into the grooves 33. After the contour discs have moved inwardly to a predetermined extent, the yarn, as the drum 27 rotates, no longer falls into the grooves 33. As a result, the amplitude of the transversal stroke is decreased very abruptly and from that moment on, the course of yarn deposition in the vicinity of inversion points 65 has a course as indicated in dash-dot lines at 72 in FIG. 8. As the contour wheel 50 continues to rotate, the magnitude of the transversal yarn stroke continuously decreases until a minimum value is reached in which the course of yarn deposition in the range of the inversion points 65 follows the curve portion designated at 73 in FIG. 8. Thereafter, the contour discs are displaced continuously outwardly away from one another and, accordingly, the transversal yarn stroke continuously increases until, at a certain moment during the outward motion of the contour discs, the yarn again falls into the grooves 33 of the drum 27. At that moment, the course of yarn deposition shifts abruptly to curve 64 and a maximum transversal stroke is resumed.

It is thus seen that the yarn, during the inward motion of the contour discs, is brought out very abruptly from those ranges in which beads may be formed and thereafter, for a number of revolutions of the cross-coil package, it is deposited thereon approximately evenly in the vicinity of the inversion points between the two curve ranges. In the remaining, usually much longer portion of each cycle, the transversal yarn stroke is set to its maximum value.

It is to be understood that in apparatuses wherein the transversal yarn stroke is caused by rotating contour discs, instead of the afore-described preferred, exemplary embodiment it is feasible to fixedly attach the contour discs to their respective 5 drive shafts. In such a case each contour disc preferably has its own drive shaft and the amplitude of the transversal yarn stroke is varied by shifting the drive shafts themselves in a direction nonnal to the axis of rotation.

It is further feasible to rotate the contour disc pairs in opposed directions. The rotary motion of the contour disc pairs is then coordinated in such a manner that they continuously position the yarn on the yarn guide bars disposed adjacent the contour discs.

That which is claimed is:

1. In an apparatus for winding yarn to form a cross-coil type yarn package on a bobbin, the improvement comprising,

A. means imparting a transversal reciprocating motion to said yarn in a direction substantially parallel with the length dimension of said bobbin, said means including 1. a plurality of parallel-disposed rotating drive shafts,

2. at least one contour disc operatively connected to each drive shaft, each contour disc rotating in a plane parallel to the length dimension of said yarn package, each contour disc having a contour edge for engagement with said yarn traversed thereby,

3. at least one yarn guide disposed adjacent and parallel to the contour discs and to the length of said yarn package, cause deposition of said yarn on said bobbin along a distance constituting the length of said yarn package and C. means for reducing the amplitude of said transversal reciprocating motion from said maximum value for predetermined periods during the winding operation to cause, for the duration of said periods, deposition of said yarn on said bobbin along a distance smaller than the length ofsaid yarn package, the last-named means including a control device for displacing said contour discs normal to their axis of rotation.

2. An improvement as defined in claim 1, including A. means for holding said drive shafts in a fixed position and B. means supporting each contour disc for a movement radially towards and away from its associated drive shaft.

3. An improvement as defined in claim 2, wherein with each 45 drive shaft there is associated a contour disc pair formed of two contour discs disposed in a coplanar relationship and oriented at 180 with respect to one another, each contour disc pair rotates with the associated drive shaft as a unit; adjacent contour disc pairs cooperate in imparting to said yarn said reciprocating motion along said yam guide; said means for reducing the amplitude of said transversal reciprocating motion includes means for moving the contour discs forming a pair, simultaneously and equally towards and away from their 55 associated drive shaft.

4. An improvement as defined in claim 3, wherein said means for reducing the amplitude of said transversal reciprocating motion includes A. an abutment integral with each contour disc and extending parallel with the associated drive shaft,

B. a setting ring mounted on each drive shaft and displaceable axially thereon, said setting ring includes a cam face engaging the abutments of the contour discs forming one pair for simultaneously displacing said contour discs in opposite directions normal to the drive shaft when said setting ring is axially displaced thereon and C. means for axially displacing each setting ring on its associated drive shaft.

5. An improvement as defined in claim 3, wherein said 70 means for reducing the amplitude of said transversal reciprocating motion includes A. reciprocable means operatively connected to said contour discs and B. a rotary contour or cam wheel operatively connected to said reciprocable means for periodically moving said contour discs into and from an outermost or normal position in which they cause said transversal reciprocating motion to assume said normal value.

6. An improvement as defined in claim 5, wherein said reciprocable means is formed of a bar or push rod.

7. An improvement as defined in claim 6, including A. an oscillatable axle,

B rocker arm means carried by said axle and engaging said bar and C. means operatively connecting said cam wheel with said axle for causing angular displacements thereof.

8. An improvement as defined in claim 7, wherein said rocker arm means are fixedly secured to said axle; said means operatively connecting said cam wheel with said axle includes an additional rocker arm fixedly secured to said axle and engaging said cam wheel.

9. An improvement as defined in claim 5, including a main drive shaft for rotating the drive shafts associated with said contour discs with identical speeds and for rotating said cam wheel with a speed substantially less than that of said lastnarned drive shafts.

10. An improvement as defined in claim 1, including means for rotating all said contour discs in the same direction.

1 1. An improvement as defined in claim 10, said yarn guide including means forming at least one yarn guiding slot disposed adjacent said contour discs for guiding said yarn passing therethrough, said guiding slot has a height slightly larger than the diameter of said yarn.

12. An improvement as defined in claim 1, including means for rotating adjacent drive shafts in opposed directions.

at t I t i

Claims

1. In an apparatus for winding yarn to form a cross-coil type yarn package on a bobbin, the improvement comprising, A. means imparting a transversal reciprocating motion to said yarn in a direction substantially parallel with the length dimension of said bobbin, said means including 1. a plurality of parallel-disposed rotating drive shafts, 2. at least one contour disc operatively connected to each drive shaft, each contour disc rotating in a plane parallel to the length dimension of said yarn package, each contour disc having a contour edge for engagement with said yarn traversed thereby, 3. at least one yarn guide disposed adjacent and parallel to the contour discs and to the length of said yarn package, cause deposition of said yarn on said bobbin along a distance constituting the length of said yarn package and C. means for reducing the amplitude of said transversal reciprocating motioN from said maximum value for predetermined periods during the winding operation to cause, for the duration of said periods, deposition of said yarn on said bobbin along a distance smaller than the length of said yarn package, the last-named means including a control device for displacing said contour discs normal to their axis of rotation.

3. An improvement as defined in claim 2, wherein with each drive shaft there is associated a contour disc pair formed of two contour discs disposed in a coplanar relationship and oriented at 180* with respect to one another, each contour disc pair rotates with the associated drive shaft as a unit; adjacent contour disc pairs cooperate in imparting to said yarn said reciprocating motion along said yarn guide; said means for reducing the amplitude of said transversal reciprocating motion includes means for moving the contour discs forming a pair, simultaneously and equally towards and away from their associated drive shaft.

3. at least one yarn guide disposed adjacent and parallel to the contour discs and to the length of said yarn package, cause deposition of said yarn on said bobbin along a distance constituting the length of said yarn package and C. means for reducing the amplitude of said transversal reciprocating motioN from said maximum value for predetermined periods during the winding operation to cause, for the duration of said periods, deposition of said yarn on said bobbin along a distance smaller than the length of said yarn package, the last-named means including a control device for displacing said contour discs normal to their axis of rotation.

4. An improvement as defined in claim 3, wherein said means for reducing the amplitude of said transversal reciprocating motion includes A. an abutment integral with each contour disc and extending parallel with the associated drive shaft, B. a setting ring mounted on each drive shaft and displaceable axially thereon, said setting ring includes a cam face engaging the abutments of the contour discs forming one pair for simultaneously displacing said contour discs in opposite directions normal to the drive shaft when said setting ring is axially displaced thereon and C. means for axially displacing each setting ring on its associated drive shaft.

5. An improvement as defined in claim 3, wherein said means for reducing the amplitude of said transversal reciprocating motion includes A. reciprocable means operatively connected to said contour discs and B. a rotary contour or cam wheel operatively connected to said reciprocable means for periodically moving said contour discs into and from an outermost or normal position in which they cause said transversal reciprocating motion to assume said normal value.

7. An improvement as defined in claim 6, including A. an oscillatable axle, B. rocker arm means carried by said axle and engaging said bar and C. means operatively connecting said cam wheel with said axle for causing angular displacements thereof.

9. An improvement as defined in claim 5, including a main drive shaft for rotating the drive shafts associated with said contour discs with identical speeds and for rotating said cam wheel with a speed substantially less than that of said last-named drive shafts.

11. An improvement as defined in claim 10, said yarn guide including means forming at least one yarn guiding slot disposed adjacent said contour discs for guiding said yarn passing therethrough, said guiding slot has a height slightly larger than the diameter of said yarn.