A YARN TRAVERSING METHOD AND AN APPARATUS THEREFOR

Abstract: First (13,14) and second (15,16) traverse devices comprising rotary blades are overlapped, and the first traverse device conveys a yarn to an traverse end, and the second traverse device (15,16) receives the yarn from one of the rotary blades of the first traverse device (13,14) and engages it with another rotary blade of the first traverse device (13,14).

Description: This invention relates to a method and an apparatus for traversing a yarn along a bobbin frictionally driven through a contact roller, by means of a traversing apparatus disposed at a predetermined distance from a fulcrum for the traversing motion, which method comprises: conveying said yarn to first and second ends of a traversing path by a first traversing means comprising at least one pair of rotary blades rotatable in opposite directions and operable to impart to said yarn a traversing motion substantially corresponding to a full traversing stroke and by transferring said yarn conveyed by said first traversing means to a second traversing means disposed downstream by a predetermined distance from said first traversing means. A method and an apparatus, respectively, of this general type are known from EP-A-0 166 292, which discloses a winding machine comprising a yarn traversing apparatus including a first traversing means comprising a guide rail and a pair of oppositely rotating arms and a second traversing means. According to the teachings of this document, the second traversing means comprises a grooved roller which is positioned between the first traversing means and the yarn package being wound. The second traversing means controls the movement of the yarn by means of a helical groove formed in the grooved roller. More specifically, the traversing movement of the yarn is controlled by means of the design of the groove and, additionally, by the relative location of said first and second traversing means. The shape of the groove cannot be varied in a given grooved roller. In addition, there is the problem that the yarn cannot easily follow the groove due to the inertia of the yarn. Accordingly, it is difficult to control the movement of the yarn at its points of reversal, i.e. at the ends of the traversing movement. DE-A-2 808 721 also discloses a traversing mechanism which comprises slot-like yarn guides on closely spaced driving members rotating in opposite directions. A deflector at each end of the traversing path assists the transfer of the yarn from a guide on one driving member to a guide on the other guiding member. The slot-like guides and the deflector means of the known traversing mechanism commonly constitute a traversing means corresponding to the first traversing means of the present invention. Further, conventionally known traversing apparatuses are, for example, disclosed in JP-A-53-22178, JP-A-46-36258 and JP-A-59-194977. However, in these conventionally known apparatuses, the yarn temporarily comes in a free condition, i.e., the yarn comes in an unstable condition, when it is transferred from one of oppositely rotating yarn guides to the other yarn guide. Accordingly, there occurs the disadvantage that the obtained yarn quality is deteriorated because high shoulders are formed at ends of the packages corresponding to the ends of the traversing movement. Further, there occurs another disadvantage, which is sometimes referred to as "cob-webbing" and wherein a yarn wound on the shoulders is slipped down from the shoulders. Especially, when a yarn is wound at a high speed higher than 5,000 m/min, the yarn is fluctuated due to the moment of inertia when the traverse motion is reversed, and the above-described disadvantages are remarkable. In order to obviate the above-described disadvantages, in JP-A-54-3985, it is proposed to dispose deflecting guides at certain positions inside the area encircled by lines connecting the traverse ends and a fulcrum of the traverse motion. However, the deflecting guides guide the yarn only in very limited regions near the traverse ends. Accordingly, the fluctuation of the yarn is not fully prevented from occurring at the traverse ends due to the moment of inertia. As a result, there often occurs a so called cob-webbing wherein a yarn wound on the shoulders is slipped down from the shoulders and further winding of a yarn becomes impossible. If it is desired to fully prevent such phenomena, the deflecting guides which are disposed above the traverse guide must be displaced toward the center of the traverse stroke. However, if this attempt is applied, the deflecting angle of the yarn at the deflecting guides increases, and the yarn is strongly rubbed against the deflecting guide. Accordingly, there is the disadvantage that the yarn quality is deteriorated since the tension in the yarn is enhanced. It is an object of the present invention to provide a new method for traversing a yarn in an apparatus for continuously winding the yarn to form a wound yarn package, by which method the above-described disadvantages are obviated. It is another object of the present invention to provide an apparatus for effecting the above-described method. It is a further object of the present invention to provide a traversing method and a traversing apparatus, by which a yarn is surely traversed and wound in a package without forming high shoulders or cob-webbing. Regarding the method, according to the present invention, the above-described object is achieved by a method of the type indicated at the outset and being characterized in that said second traversing means are disposed at positions near the ends of the traversing path and comprise rotary blades and that said second traversing means are designed so as to release said yarn from said rotary blades of said first traversing means, for guiding said yarn at the ends of the traversing path and to bring said released yarn into engagement with another rotary blade of said first traversing means rotating in a direction opposite to the direction of rotation of said first blade of said first traversing means. Regarding the apparatus, according to the present invention, the above-described object is achieved by an apparatus for traversing a yarn along a bobbin, frictionally driven by a contact roller, said traversing apparatus comprising a first traversing means for traversing said yarn for a substantially full traversing stroke along a traversing path, said first traversing means being disposed at a position located downstream by a predetermined distance from a fulcrum for the traversing motion, said first traversing means comprising at least a pair of rotary blades rotatable in opposite directions, and a second traversing means disposed downstream by a predetermined distance from said first traversing means, which apparatus is characterized in that said second traversing means is disposed at positions near the ends of the traversing path and comprises rotary blades for receiving said yarn conveyed by said first traversing means and for conveying said yarn to one of said ends of said traversing path. In preferred embodiments of the present invention, the first and second traversing means are so arranged that the yarn is moved by means of the rotary blade of the second traversing means to a position where the fulcrum, the rotary blade of the first traversing means, and a contacting point between the yarn conveyed by the rotary blade of the second traversing means and the contact roller align with a straight line or a line slightly deviated from the straight line toward the center of the traversing motion, and that thereafter the yarn is released from the rotary blade of the second traversing means. The present invention will now be explained in detail with reference to the accompanying drawings, wherein: Fig. 1 is a schematic front view of a winding apparatus wherein a first embodiment of a traversing apparatus of the present invention is installed; Fig. 2 is a plan view seen in direction of arrow A in Fig. 1 and showing the traversing apparatus of the present invention; Fig. 3 is a side view seen in direction of arrow B in Fig. 2; Fig. 4 is a cross sectional view taken along line C-C in Fig. 2; Fig. 5 is a cross sectional view taken along line D-D in Fig. 2; Fig. 6 is a cross sectional view taken along line E-E in Fig. 2; Figs. 7(a) to 7(f) are front views sequentially showing the conditions wherein a yarn is transferred according to the present invention; Figs. 8(a) to 8(f) and 9(a) to 9(f) are plan views sequentially showing the conditions wherein a yarn is transferred according to the present invention; Fig. 10 is a schematic front view of another embodiment of a traversing apparatus according to the present invention; Fig. 11 is an enlarged cross sectional view of an essential part of Fig. 10 and taken along line C-C; Figs. 12(a) to 12(d) are plan views sequentially showing the conditions wherein a yarn is transferred according to the present invention; Fig. 13 is a plan view of another embodiment; Fig. 14 is a front view of the embodiment of Fig. 13; Figs. 15(a) to 15(d) are plan views sequentially showing the conditions wherein a yarn is transferred in the apparatus illustrated in Fig. 13; Fig. 16 is a plan view showing the principle of the embodiment shown in Fig. 13; Fig. 17 is a plan view of a still further embodiment; and Figs. 18 and 19 are traverse stroke diagrams according to embodiments of the present invention. A first embodiment of the present invention will now be described with reference to the accompanying drawings, wherein Fig. 1 is a schematic front view of a winding apparatus provided with a traversing apparatus of the present invention, Fig. 2 is a plan view seen in direction of arrow A in Fig. 1 and showing the traversing apparatus of the present embodiment, Fig. 3 is a side view seen in direction of arrow B in Fig. 2, Fig. 4 is a cross sectional view taken along line C-C in Fig. 2, Fig. 5 is a cross sectional view taken along line D-D in Fig. 2, Fig. 6 is a cross sectional view taken along line E-E in Fig. 2, Figs. 7 to 9 are front views and plan views sequentially showing the conditions wherein a yarn is transferred at the right traverse end, and Fig. 7(a), Fig. 8(a) and Fig. 9(a) illustrate conditions at the same instances, and so on. In Fig. 1, after a yarn Y is drawn by a drawing apparatus (not illustrated), the yarn Y is fed through a snail guide 8, which serves as a fulcrum of traverse motion, and is wound by a winding apparatus W. The winding apparatus W comprises a traversing apparatus 3 for traversing the yarn Y to and fro, a contact roller 4 and a bobbin holder 5. The traversing apparatus 3 and the contact roller 4 are mounted on a slide block 2 which is vertically movable. The bobbin holder 5 is rotatably supported on a machine frame and has two bobbins 6 inserted thereonto in the present embodiment. The contact roller 4 contacts the bobbins 6 inserted onto the bobbin holder 5. Although the winding apparatus W of the present embodiment is a friction type winder wherein the contact roller frictionally drives the bobbin holder 5, the winding apparatus W may be a spindle drive type winder wherein a spindle of the bobbin holder is connected to a drive motor and is driven thereby. The traversing apparatus 3 of the present embodiment is so disposed as to face the contact roller 4. However, a traversing apparatus may be disposed above a contact roller 4 in such a manner that a guide which traverses a yarn projects toward the yarn passage. When a yarn Y is wound, the yarn Y is pressed onto the contact roller 4 at a point Q while it is traversed by the traversing apparatus 3, and the yarn Y is wound onto the bobbin 6, which is inserted onto the bobbin holder 5 and which is driven by the contact roller 4, to form a yarn package 7. The yarn Y is traversed to and fro by means of the traversing apparatus 3 illustrated in Figs. 2 and 3. The traversing apparatus 3 will now be explained in detail. A case 10 projects from a slide block 25 and has units U and U' detachably mounted thereon by bolts 24a, 24b, 24c and 24d. The construction of the units U and U' will now be explained referring to Fig. 4. A hollow spindle 30 is rotatably supported by cases 12 and 12' via a pair of bearings 27 and 27'. The upper portion of the hollow spindle 30 has blades 13 and 13' secured thereto by bolts 41. The blades 13 and 13' are formed in a lever shape and traverse the yarn Y. A spindle 28 is disposed in the hollow portion of the hollow spindle 30 in such a manner that it is co-axial with the hollow spindle 30 and its upper end exceeds the upper end of the hollow spindle 30. The spindle 28 is rotatably supported by the case 12 and the hollow spindle 30 via bearings 26 and 26'. A boss 29 is fixed to the upper portion of the spindle 28 by a key 38, and blades 14 and 14' are secured to the boss 29 by bolts 40. The blades 14 and 14' are also formed in a lever shape and traverse the yarn Y. A stop plate 33 is secured to the upper end of the spindle 28 by a bolt 39 so as to axially fasten the boss 29 and the bearings 26 and 26' The blades 13, 13', 14 and 14' have yarn guides, respectively, and the blades 14 and 14' are located above the blades 13 and 13'. The lower end of the hollow spindle 30 has a gear 35 secured thereto by a bolt 36. Further, the spindle 28 has a gear 34 fixed thereto by a key 37. The gear 34 and the bearing 26 are axially secured by a nut 51 threaded with a screw formed at the lower end of the spindle 28. At the turning point of the traversing motion, i.e., the position where the blade 13 or 13' meets with the blade 14 or 14', a guide 16 is fixed to the case 12 as illustrated in Fig. 2 so that it locates between the blades 13 and 14 as illustrated in Fig. 4. The guide 16 serves to release the yarn Y, which has been conveyed by the blade 13 or 14, from the blade 13 or 14. The surfaces 16a and 16b of the guide 16 are inclined outwardly from the traversing region so that the yarn Y is released from the blade 13 or 14 when it is pushed onto the inclined surfaces 16a or 16b by the blade 13 or 14. The portion 16c of the guide 16 is connected to the inclined surface 16a and 16b and prevents the yarn Y from fluctuating in the horizontal direction in Fig. 1 while the yarn Y is traversed. The portion 16c also serves to limit the amount of radius of gyration of the yarn Y which is conveyed by the blade 13 or 14. The blades 13 and 14 and the guide 16 constitute a first traversing means. In the present embodiment, the separate guides 16 are individually disposed at positions corresponding to the traverse ends. However, both the guides may be connected in one body, and the connecting portion may be curved so as to adjust the traversing speed of the yarn Y which is conveyed by the blades 13 and 14. As illustrated in Fig. 2, at the yarn turning points of the first traversing means, blades 15a and 15b are disposed downstream of the first traversing means so that they receive the yarn Y which has been conveyed by the blades 13 and 14, and move it to the corresponding traversing ends. As illustrated in Figs. 2 and 9, each of the blades 15a and 15b is formed as a circular disk provided with a triangular projection. The blades 15a and 15b are fixed to spindles 44a and 44b by bolts 49a and 49b as illustrated in Figs. 4 and 6. The spindle 44a locates at the right traversing end and the spindle 44b locates at the left traversing end. The spindles 44a and 44b are rotatably supported on the case 12 by bearings 42a, 42a', 42b and 42b'. As illustrated in Fig. 4, a gear 45b is fixed to the spindle 44b at the upper central portion thereof by a key 46b and meshes with the gear 35 so as to be driven thereby. Similarly, as illustrated in Fig. 6, a gear 45a is fixed to the spindle 44a at the lower central portion thereof by a key 46a and meshes with the gear 34 so as to be driven thereby. As illustrated in Fig. 4, the bearing 42b, the gear 45b, a distance piece 47b and the bearing 42b' are inserted onto the spindle 44b and are secured by a nut 50b. Similarly, as illustrated in Fig. 6, the bearing 42a, the gears and 45a, a distance piece 47a and the bearing 42a' are inserted onto the spindle 44a and are secured by a nut 50a. As illustrated in Figs. 2 and 4, the guide 16 is provided with guides 17b and 17a for releasing the yarn Y, which has been conveyed to the traverse turning portion by the blade 15a or 15b, from the blade 15b or 15a. The guides 17a and 17b are provided with inclined surfaces like the guide 16, which inclined surfaces are inclined outwardly from the traversing region so that the yarn is released from the blade 15a or 15b when it is pushed onto the inclined surfaces of guides 17a or 17b by the blades 15a or 15b. The blades 15a and 15b and the guides 17a and 17b constitute a second traversing means. Gears 52 and 55 are integrally formed with a spindle 56 which is rotatably supported on the case 12 at the right portion in Fig. 4 via bearings 53 and 53'. The gear 55 meshes with the gear 35, and the other gear 52 meshes with a gear 32 which is illustrated in Fig. 5. The gear 32 is formed integral by with a spindle 45 together with a gear 31, and the spindle 45 is rotatably supported on the case 12 via bearings 46 and 46'. The gear 31 illustrated in Fig. 5 meshes with the gear 34 illustrated in Fig. 4. The lower end of the spindle 45 has a pulley 48 fixed thereto by a key 54, and the rotation of the pulley 48 is transmitted to the gears 34 and 35 through the spindle 45 and gears 31, 32, 52 and 55. More specifically, because of engagement of the gears, the spindle 28 illustrated in Fig. 4 and the spindle 44b illustrated in Fig. 4 are rotated in a clockwise direction in Fig. 2, and the hollow spindle 30 illustrated in Fig. 4 and the spindle 44a illustrated in Fig. 6 are rotated in a counter-clockwise direction in Fig. 2. As illustrated in Fig. 3, the case 10 has a motor 11 mounted thereon. The output spindle of the motor 11 has a pulley 18 fixed thereto, and pulleys 21 and 22 (see Figs. 2 and 3) are mounted on spindles rotatably projecting from the case 10. An endless timing belt 23 is wrapped around the pulleys 18, 21 and 22 and is also engaged with the pulleys 48 and 48' disposed in the units U and U' so as to drive the units U and U'. The above-explained first and second traversing means are adjusted their phases and timings so that they can perform the yarn transferring steps which will be described below. The yarn transferring steps will now be explained with regard to the turning portion illustrated in the right in Fig. 2. As denoted by an arrow in Fig. 7(a), a blade 13f conveys a yarn Y from the left to the right. When the yarn Y nears the traversing end, the blade 15a, which is disposed below the blade 13f, receives the yarn Y extending between the blade 13f and the outer periphery of the contact roller 4. At the moment, the blade 15a receives the yarn Y which has been conveyed by the blade 13f without disturbing the movement of the yarn Y, and the yarn Y is displaced to the right by both the blades 13f and 15a as illustrated in Figs. 8(b) and 9(b). When the yarn Y is moved to the traversing end, the yarn Y is pushed onto the inclined surface 16a of the guide 16 as shown in Fig. 8(c) and is released from the blade 13f as shown in Fig. 8(d), and then the yarn is conveyed only by the blade 15a as shown in Fig. 9(d). At a position between the snail guide 8, which serves as a fulcrum of the traverse motion, and the blade 15a, the yarn Y, which is conveyed by the blade 15a, engages with the blade 14f, which is rotating in a direction opposite to that of the blade 13f. However, the yarn Y is continued to be conveyed by the blade 15a toward the traverse end. When the yarn Y reaches at such a position that the snail guide 8 for fulcrum of the traverse motion, the blade 14f and the contacting point Q where the yarn Y conveyed by the blade 15a contacts with the contact roller 4 align with a straight line as illustrated in Fig. 7(e) or a line slightly deviated from the straight line toward the center of the traverse motion, the yarn Y, which has been conveyed by the blade 15a, engages with the guide 17a, is pushed onto the inclined surface thereof and is released from the blade 15a. It is preferred that the angle formed between the above-described straight line and the axis of the contact roller 4 is set about a winding angle. When the yarn Y is traversed as described above, it is always in a tight condition at the traverse turning portion, and accordingly, the yarn Y is not loosened when it is disengaged from the blade 15a. Thus, formation of cob-webbing can be prevented. Further, when the yarn is disengaged from the blade 15a, the yarn Y is pulled by the blade 14f toward the center of the traverse motion as illustrated in Fig. 7(f), the yarn Y can be sharply turned. Accordingly, high shoulders around the ends of a yarn package can be prevented from occurring. Another embodiment will now be explained with reference to Figs. 10 to 12. In this embodiment, in addition to the above-described traversing apparatus of the first embodiment, such an additional means is provided that during formation of a package by traversing the yarn at a predetermined traverse stroke in an axial direction of the bobbin by the first and second traversing means, the second traversing means is continuously or discontinuously made not to serve the yarn for several strokes or to alter degree of service for several strokes so that the yarn is traversed at a shorter traverse stroke. Accordingly, the same parts as those in the first embodiment are designated by the same reference numerals, and further explanation of the construction similar to that of the above-described first embodiment is omitted here. As illustrated in Fig. 10, in this embodiment, a guide 57 is diagrammatically formed in a triangular shape and is disposed normal to the yarn passage above the second traversing apparatus. The guide 57 is movable between a position where the guide 57 covers a yarn engaging point of the second traversing means as seen along a yarn passage and a position where the guide 57 does not cover the yarn engaging point of second traversing means. More specifically, referring to Fig. 10, elongated guide holes 57a and 57b formed near the lower apexes of the guide 57 engage with pins 64a and 64b, respectively, which project from the guides 17a and 17b, respectively. Further, a pin 62 projects at the upper apex of the guide 57. The case 12 has a pin 63, which swingably supports an L-shaped lever 60. An end of the L-shaped lever 60 engages with the pin 62, and the other end of the L-shaped lever 63 is connected to a bar 59 via a pin 61. The case 12 has a fluid pressure cylinder 58 swingably mounted thereon, and a rod 58a of the fluid pressure cylinder 58 is connected to the bar 59. An appropriate program has been previously programmed in a microcomputer (not shown). During the winding operation, the fluid pressure cylinder 58 is actuated in accordance with the previously memorized program via an electro-magnetic valve (not shown) at a predetermined time interval for a predetermined duration, and the guide 57 covers the yarn engaging portion of the second traverse means so that the second traverse means does not guide the yarn Y. The above-explained first and second traversing means and the guide are adjusted their phases and timings so that they can perform the following yarn transferring steps. The yarn transferring steps will now be explained with regard to the turning position illustrated in the right in Fig. 10. First, the guide 57 is move backwardly, i.e, upwardly in Fig. 10, so that the second traversing means can be seen below the guide when it is seen along a yarn passage as illustrated in Fig. 12. Accordingly, the guide 57 substantially does not guide the yarn Y. Thus, the yarn Y is traversed in a manner similar to that explained with reference to Figs. 7 to 9. When the guide 57 is moved forwardly, i.e., downwardly. in Fig. 10, the yarn engaging portion of the second traversing means is covered by the guide 57 if it is seen along a yarn passage, i.e., in a condition illustrated in Fig. 12, the second traversing means does not guide the yarn Y. As a result, the yarn Y is wound while it is traversed at a traverse stroke shorter than a predetermined normal traverse stroke. The steps of this instance will now be described with reference to the above-described Figs. 7 and 8 and Fig. 12. In Figs. 7(a), 8(a) and 12(a), the guide 57 is pushed toward the passage of the running yarn Y and it covers the blade 15 so that the blade 15 does not guide the yarn Y, and the yarn Y is conveyed from the left to the right by the blade 13f. As illustrated in Figs. 7(b), 8(b) and 12(b), the yarn Y is moved to the right by the blade 13f and the yarn Y nears the traverse end. However the blade 15a is covered by the guide 57 and does not guide the yarn Y, and accordingly, the yarn Y is conveyed by only the blade 13f. In Figs. 7(c), 8(c) and 12(c), the yarn Y conveyed by the blade 13f is released from the blade 13f by means of the inclined surface 16a of the guide 16. In that moment, the yarn Y is not engaged with the blade 15a. Accordingly, the yarn Y is not conveyed to the traverse end which is common when the guide 57 is moved backwardly. Since the yarn Y is wound onto a package at a certain winding angle, the yarn Y released from the blade 13f is delayed a small distance toward the center of the traverse motion, wherein said distance equals the (distance between the blade 13f and the point Q where the yarn Y contacts with the contact roller 4γ multiplied by the tangent of said certain angle. The yarn Y is returned keeping the small distance. Accordingly, the width of the package wound under this condition is shorter than that wound under the normal condition by a distance which amounts to twice said small distance. Then, the yarn is released from the blade 13f as illustrated in Figs. 8(d) and 12(d), it is engaged with the blade 14f which rotates in a direction opposite to that of the blade 13f and is moved to the left. During formation of a package with traversing the yarn at a predetermined traverse stroke by means of the first and second traversing means wherein the guide 57 is moved backwardly (Fig. 9), the winding operation only by the first traversing means is continuously or discontinuously repeated for several strokes. Thus, a good yarn package which is free from high shoulders or cob-webbing can be obtained. For example, traverse motion can be controlled in accordance with a traverse stroke diagram illustrated in Fig. 18. In this example, the traverse stroke is shortened by between 5 and 15 mm for between one tenth and one thirtieth of the normal traverse strokes. Although the guide 57 is disposed upstream of the second traversing means in this embodiment, it may be disposed at a position between the second traversing means and the contact roller 4. In this embodiment the guide 57 is used so that the second means does not guide the yarn, a still further embodiment will now be explained. In the embodiment illustrated in Figs. 13 and 14, the guides 17a and 17 b are moved toward the center of the traverse motion (see Fig. 16) so that the amount for which the second traversing means guide the yarn Y is varied or so that the second traversing means is made not to guide the yarn Y at all. Parts similar to those in the above-described embodiments are designated by the same reference numerals and their further explanation is omitted here. The guides 17a and 17b are slidably mounted on the case 12 by means of pins 57a and 57b. The case 10 has pulleys 60 and 62 rotatably mounted thereon. The guides 17a and 17b are connected to a wire 59 wrapped around the pulleys 60 and 62. The wire 59 is further connected to a rod 58a of a fluid pressure cylinder 58 by means of a joint 66. An appropriate program is previously programmed in a microcomputer (not shown). During the winding operation, the fluid pressure cylinder 58 is actuated in accordance with the previously memorized program via an electro-magnetic valve (not shown) at a predetermined time interval for a predetermined duration, the degree of guidance of the second traversing means to the yarn Y is varied. The guides 17a and 17b may be disposed downstream of the blades 15a and 15b. In this embodiment, a fluid pressure cylinder is used to move the guides 17a and 17b, nevertheless, any other appropriate means, such as a stepping motor or a servo motor may be used in place of the fluid pressure cylinder. When the guides 17a and 17b do not cover the second traversing means, the yarn Y is traversed at a predetermined traverse stroke in a manner similar to that explained with reference to Figs. 7 to 9. When the guides 17a and 17b are moved toward the center of the traverse motion, the yarn Y is conveyed by the blade 13f to the right as illustrated in Figs. 7(b), 8(b) and 15 (b). When the yarn nears the right traverse end, the yarn is conveyed by only the blade 17a since the blade 15a is covered by the guide 17a,. In Figs. 7(c), 8(c) and 15(c), the yarn Y conveyed by the blade 13f is released from the blade 13f by means of the guide 17a, and accordingly, the traverse stroke is shorter than that of the normal condition. Thus, such a traverse control as illustrated in Fig. 19 can be done. In an embodiment illustrated in Fig. 17, the second traversing means, i.e., the guides 15a and 15b, are disposed on a swingable arm so that they can be receded from the yarn passage. The above-explanations have done with respect to the transfer of a yarn at the right side of the traverse stroke, and a similar yarn transfer is also done at the left side. Further, although traversing apparatuses are exemplified in the above-described embodiments, wherein two bobbins are inserted onto a bobbin holder so as to simultaneously wind two packages, one package or more than two packages may be wound at the same time. In addition, a manual winder provided with single bobbin holder spindle is exemplified in the above-described embodiments, however, the present invention is also applicable to an automatic winder which is provided with a plurality of bobbin holder spindles. Besides, though straightly inclined guides are used as a guide for releasing a yarn from rotary blade 15, the guide surface may be a curve of an appropriate configuration so that the speed of the yarn Y conveyed by the blade is adjusted. Furthermore, the second traversing means serves a yarn only near the traverse ends in the above-described embodiments, the second traversing means may serve the yarn in whole the traverse region. In an embodiment, the centers of rotation of the rotary blades rotatable in opposite directions may be deviated in place of stationary inclined guides in the above-described embodiments so that the yarn can be released from the rotary blades of the first traversing means. Although the yarn Y is released from the rotary blade 15 by means of a stationary inclined guide 17a after the yarn Y is received by the rotary blade of the second traversing means in the above described embodiments, a rotary blade (not shown) rotatable in a direction opposite to the rotary blade 15a may be disposed so as to release the yarn from the rotary blade 15. As described above, the traversing apparatus of the present invention comprises: a first traversing means for traversing a substantially full traverse stroke disposed at a position located downstream by a predetermined distance from a fulcrum for traverse motion; the first traversing means comprising at least a pair of rotary blades rotatable in opposite directions; and a second traversing means disposed downstream by a predetermined distance from the first traversing means at positions near traverse ends and which comprises rotary blades for receiving the yarn conveyed by the first traversing means and conveying the yarn to one of the traverse ends. Accordingly, a yarn is surely traversed and wound in a package without forming high shoulders or cob-webbing. Especially, it is preferred that the first and second traversing means are so arranged that the yarn is, moved by means of the rotary blade of the second traversing means to a position where the fulcrum, the rotary blade of the first traversing means, and a contacting point between the yarn conveyed by the rotary blade of the second traverse means and the contact roller align with a straight line or a line slightly deviated from the straight line toward the center of the traverse motion, and that thereafter the yarn is released from the rotary blade of the second traversing means. The yarn is always kept in a tight condition according to this arrangement, and the advantages of the present invention is further enhanced. Especially, when a yarn is wound at a high speed higher than 5,000 m/min, wherein the yarn is usually fluctuated due to the moment of inertia when the traverse motion is reversed, the above-described arrangement is useful to achieve the above-described advantages of the present invention.

Claims: A method of traversing a yarn (Y) along a bobbin (6) frictionally driven through a contact roller (4), by means of a traversing apparatus (3) disposed at a predetermined distance from a fulcrum (8) for the traversing motion, which method comprises: conveying said yarn (Y) to first and second ends of a traversing path by a first traversing means comprising at least one pair of rotary blades (13, 13', 14, 14') rotatable in opposite directions and operable to impart to said yarn (Y) a traversing motion substantially corresponding to a full traversing stroke and by transferring said yarn (Y) conveyed by said first traversing means (13, 13', 14, 14') to a second traversing means (15a, 15b, 15c, 15d) disposed downstream by a predetermined distance from said first traversing means, said method being characterized in that said second traversing means are disposed at positions near the ends of the traversing path and comprise rotary blades (15a, 15b, 15c, 15d) and that said second traversing means are designed so as to release said yarn (Y) from said rotary blades (13, 13', 14, 14') of said first traversing means, for guiding said yarn (Y) at the ends of the traversing path and to bring said released yarn (Y) into engagement with another rotary blade (13, 13', 14, 14') of said first traversing means rotating in a direction opposite to the direction of rotation of said first blade of said first traversing means. The method according to claim 1, wherein said yarn (Y) is moved by means of said rotary blade (15a, 15b, 15c, 15d) of said second traversing means to a position where said fulcrum (8), said rotary blade (13, 13', 14, 14') of said first traversing means, and a contacting point (Q) between said yarn (Y) conveyed by said rotary blade (15a, 15b, 15c, 15d) of said second traversing means and said contact roller (4) are in alignment along a straight line or a line slightly deviated from said straight line toward the center of said traversing motion, and then said yarn (Y) is released from said rotary blade (15a, 15b, 15c, 15d) of said second traversing means. The method according to claim 1 or 2, wherein during formation of a package by traversing said yarn (Y) at a predetermined traversing stroke in an axial direction of said bobbin (6) by said first and second traversing means, for several strokes, and continuously or discontinuously, said second traversing means is rendered inoperative at least partly to alter degree of yarn displacement, so that said yarn (Y) is traversed at a shorter traversing stroke. An apparatus (3) for traversing a yarn (Y) along a bobbin (6), frictionally driven by a contact roller (4), said traversing apparatus (3) comprises: a first traversing means (13, 13', 14, 14') for traversing said yarn (Y) for a substantially full traversing stroke along a traversing path, said first traversing means being disposed at a position located downstream by a predetermined distance from a fulcrum (8) for the traversing motion; said first traversing means comprising at least a pair of rotary blades (13, 13', 14, 14') rotatable in opposite directions; and a second traversing means (15a, 15b, 15c, 15d) disposed downstream by a predetermined distance from said first traversing means, characterized in that said second traversing means is disposed at positions near the ends of the traversing path and comprises rotary blades (15a, 15b, 15c, 15d) for receiving said yarn (Y) conveyed by said first traversing means and for conveying said yarn (Y) to one of said ends of said traversing path. The apparatus (3) according to claim 4, wherein said first and second traversing means are so arranged that said yarn (Y) is moved by means of said rotary blade (15a, 15b, 15c, 15d) of said second traversing means to a position where said fulcrum (8), said rotary blade (13, 13', 14, 14') of said first traversing means, and a contacting point (Q) between said yarn (Y) conveyed by said rotary blade (15a, 15b, 15c, 15d) of said second traversing means and said contact roller (4) are in alignment along a straight line or a line slightly deviated from said straight line toward the center of said traversing motion, and that thereafter said yarn (Y) is released from said rotary blade (15a, 15b, 15c, 15d) of said second traversing means. The apparatus (3) according to claim 4 or 5, which further comprises a guide (57) which is movable between a position where said guide (57) covers a yarn engaging point of said second traversing means as seen along a yarn passage and a position where said guide (57) does not cover said yarn (Y) engaging point of second traversing means. The apparatus (3) according to claim 4 or 5, wherein said second traversing means further comprises a plate guide (17a, 17b) which releases said yarn (Y) from said rotary blade (15a, 15b, 15c, 15d) for guiding said yarn (Y) received from said first traversing means, said plate guide (17a, 17b) being movable relative to said rotary blade (15a, 15b, 15c, 15d). An apparatus (3) according to claim 4 or 5, wherein said second traversing means further comprises a stationary guide (17a, 17b) which releases said yarn (Y) from said rotary blade (15a, 15b, 15c, 15d) for guiding said yarn (Y) received from said first traversing means, and wherein the axis of rotation of said rotary blade (15a, 15b, 15c, 15d) of said second traversing means is movable relative to said stationary guide (17a, 17b).

Inventors: SUGIOKA, TAKAMI
Applicants: TEIJIN SEIKI CO. LTD.
Application year: 1988
Main classification: B65H54
IPC codes: B65H54