Thread piecing method for rotor type open end spinning frame and apparatus therefor

Abstract: An inner rotor 5 has a recess 7 formed at a position corresponding to a navel 6 and the recess 7 has a taper surface 7a formed to the peripheral edge thereof. The end surface 6c of the navel 6 can be moved together with a support member 12 to an ordinary spinning position where it can be engaged with a thread Y drawn out through a thread guide and to a thread piecing position where it cannot be engaged therewith. When the thread is pieced, the navel 6 is disposed at the thread piecing position and after a seed thread is introduced into an outer rotor 2 from a thread drawing-out path 6b in the state that both the rotors 2, 5 are rotated, a fiber bundle in a fiber collecting portion 2a is drawn out together with the seed thread and a thread is spun without passing through the thread guide. Thereafter, the navel 6 is moved to the ordinary spinning position. While the navel 6 is being moved, the end surface 6c thereof is engaged with the thread Y which is introduced into the thread guide opened on the opening side of the outer rotor 2, so that operation proceeds to ordinary spinning. With this arrangement, the extreme end of the seed thread is caused to securely reach up to the fiber bundling unit of the outer rotor in thread piecing, whereby a spinning state in the thread piecing can smoothly proceed to the ordinary spinning state.

Description: The present invention relates to a thread piecing method according to the preamble of claim 1 and a thread piecing apparatus according to the preamble of claim 10. Specifically, the present invention relates to a thread piecing method in a rotor type open end spinning frame and an apparatus therefor by which a thread is pieced in such a manner that an inner rotor, which includes a thread guide for guiding a thread drawn out from a fiber collecting portion to the end of a thread drawing-out path, is disposed in an outer rotor which includes the fiber collecting portion in which fibers fed in a separated state are collected and bundled coaxially with the outer rotor as well as the inner rotor is positively driven independently of the outer rotor and a navel disposed at the end of the thread drawing-out path is moved nearer to the opening side of the outer rotor as compared with to an ordinary spinning position when the thread is pieced and thereafter the navel is returned to the ordinary spinning position. In general, in a rotor type open end spinning frame, sliver being fed is made to the state that fibers are separated from each other by a combing roller to remove impurities and the thus scatteringly separated fibers are transported into a rotor rotating at a high speed by an air flow generated in a fiber transportation path (fiber transportation channel) based on a negative pressure in the rotor. Then, the fibers transported into the rotor are bundled in a fiber collecting portion or groove as the maximum inside diameter portion of the rotor, drawn out from a guide hole (thread drawing-out path) disposed at the center of the navel by the action of a drawing-out roller and simultaneously twisted to a thread by the rotation of the rotor and wound around a bobbin as a package. The open end spinning frame has good productivity as compared with that of a ring spinning frame. However, the fiber bundle bundled in the fiber collecting portion is only adhered to the inner wall of the fiber collecting portion by the action of a centrifugal force caused by the rotation of the rotor. Therefore, the twist applied to the fiber bundle (thread) drawn along the guide hole is also transmitted to the fiber bundle upwardly of the point where the fiber bundle is taken off to some degree. As a result, since the fibers are twisted in the state that they are not sufficiently extended without being provided with sufficient tension, the fibers are not twisted straight, thus there is a problem that the thread is not made strong. Further, there is a drawback that fibers without a restraint force which slides toward the fiber collecting portion along the inner wall of the rotor are coiled around the fiber bundle in rotation and disturbs the outside appearance of the thread and when the threads are made of a sheet, its feeling is made bad. Further, a problem also arises in that fibers fed into the rotor from the fiber transportation path are coiled around the fiber bundle which is in a way from the fiber collecting portion to a thread drawing-out path and being twisted and disturb its outside appearance. There is proposed an apparatus comprising an inner rotor disposed in an outer rotor having a fiber collecting portion, the inner rotor being provided with a thread guide for drawing out a fiber bundle bundled in the fiber collecting as well as positively driven independently of the outer rotor (for example, JP-A-6-123020) as an apparatus for overcoming the drawback of the conventional open end thread. The Publication also discloses a thread piecing method of introducing a thread to the thread guide making use of the movement of a navel which has a thread drawing-out path formed thereto and is disposed so that the end surface thereof can move between a spinning position where the end surface can be engaged with a thread being spun through the thread guide and an evacuating position where the end surface cannot be engaged with the thread. According to this method, a thread introduction path communicating with the thread guide is disposed to the inner rotor as well as when a thread is pieced, the extreme end of a seed thread is introduced into the fiber collecting portion of the outer rotor through the thread introduction path from the thread drawing-out path in the state that the navel is located at the evacuating position. After the extreme end of the seed thread reaches the fiber collecting portion, the seed thread is drawn out together with the fiber bundle and then the navel is moved to the spinning position to permit the fiber bundle to be introduced into the thread guide. Further, as shown in FIG. 13, there is also proposed an apparatus arranged such that an inner rotor 62 is disposed nearer to the bottom side of an outer rotor 61 as compared with a plane including the fiber collecting portion 61a of an outer rotor 61 and a fiber bundle bundled in the fiber collecting portion 61a is guided to the thread drawing-out path of a navel 65 through a roller 64 disposed to the thread guide 63 of the inner rotor 62 at the end thereof on the outer rotor side thereof. In this apparatus, a thread is pieced by disposing the navel 65 at a position where the end thereof is located on the plane including the fiber collecting portion 61a and the navel 65 is disposed at a position shown in FIG. 13 in ordinary spinning operation. However, in the apparatus employing the former thread piecing apparatus, since the thread guide 63 and the thread introduction path 67 formed to the inner rotor 62 are relatively narrow as shown in FIG. 14, it is difficult for the extreme end of the seed thread inserted from the thread drawing-out path into the thread introduction path 67 to reach the fiber collecting portion in the thread piecing. On the other hand, in the latter apparatus, the seed thread introduced from the thread drawing-out path 66 can easily reach the fiber collecting portion 61a because there is no obstacle between the end surface of the navel 65 and the fiber collecting portion 61a in the thread piecing. However, there is a problem that since the thread guide 63 has a narrow width, when a spinning state in the thread piecing is transferred to an ordinary spinning state, it is difficult to smoothly introduce a thread being spun into the thread guide 63. A generic thread piecing method and a generic thread piecing apparatus are known from EP-A-0 585 824. This reference shows that for thread piecing a navel is moved to a thread piecing position and a seed thread is introduced into an outer rotor, wherein the extreme end of the seed thread is caused to reach a position where it comes into contact with a fiber bundle in a fiber collecting portion of the outer rotor. Then the fiber bundle is drawn together by means of the seed thread without causing them to pass through a thread guide of an inner rotor. After that, the navel is again moved to an ordinary spinning position, wherein the thread is introduced into the thread guide. Rollers as a guide member project beyond the surface of the inner rotor. It is an object of the present invention to further develop a thread piecing method according to the preamble of claim 1 and a thread piecing apparatus according to the preamble of claim 10 such that a smooth transfer from a thread piecing state to an ordinary spinning state can be performed. This object is achieved with respect to the method by the features indicated in the characterizing portion of claim 1 and with respect to the apparatus by the features indicated in the characterizing portion of the new claim 10. Advantageous further developments are set out in the dependent claims. According to the present invention, the method and apparatus of a rotor type open end spinning frame are capable of causing the extreme end of a seed thread to securely reach up to the fiber collecting portion of an outer rotor in thread piecing as well as transferring a spinning state in the thread piecing to an ordinary spinning state. The separated fibers fed into the outer rotor from the fiber transportation path slide along the inner wall surface of the outer rotor and are bundled to the fiber collecting portion. The fiber bundle bundled in the fiber collecting portion is taken off therefrom and drawn out as a thread while being twisted through the inner rotor. The navel is moved to the thread piecing position in thread piecing and the extreme end of the seed thread is introduced into the outer rotor from the thread drawing-out path in the state that the outer rotor is rotated and securely reaches the fiber collecting portion. After the extreme end of the seed thread reaches a position where it comes into contact with the fiber bundle in the fiber collecting portion, the fiber bundle in the fiber collecting portion is drawn out together with the seed thread and a thread is spun without passing through the thread guide of the inner rotor. Thereafter, the navel is moved to the side of the ordinary spinning position as well as the end of the navel is engaged with the thread being spun while the navel is being moved, and when the navel is further moved to the ordinary spinning position side, the above thread is introduced into the thread guide opened to the opening side of the outer rotor. Then, the navel is held at the ordinary spinning position and operation smoothly proceeds to an ordinary spinning state, thus a ratio success in thread piecing is improved. When the end of the navel is engaged with the thread being spun and moved to the ordinary spinning side, the thread rotatingly moves along the end surface of the inner rotor and when the thread reaches a position corresponding to the thread guide, it is introduced into the thread guide by a guide surface disposed rearward of the thread rotatingly moving direction across the thread guide. It is preferable that the seed thread is introduced at a speed lower than the ordinary rotational speed and the navel is moved from the thread piecing position to the ordinary spinning position after the outer rotor and the inner rotor reach the ordinary rotational speeds in the ordinary spinning. Since the navel is moved to the ordinary spinning position in the steady state in which the outer rotor can be easily synchronized with the inner rotor, the thread can be more smoothly introduced into the thread guide. In the aforesaid thread piecing method, it is preferable that the fiber bundle drawing out and spinning step is carried out by setting a rotational speed of the inner rotor to a speed different from the speed of the fiber bundle drawn out from the fiber collecting portion and the step of introducing the thread into the thread guide is carried out by changing the relative speed between the inner rotor and the fiber bundle after the rotational speeds of the outer rotor and the inner rotor reach the ordinary speeds and introducing the fiber bundle through the guide member. The relative speed can be changed by changing the rotational speed of the inner rotor or by changing the speed of at which the fiber bundle is drawn out. In this case, it is preferable that the guide member is disposed in the vicinity of the inlet of the thread guide of the inner rotor, formed in such a shape as to introduce the thread into the thread guide by permitting the relative movement of the thread guided from the fiber collecting portion to the thread drawing-out path without passing through the thread guide rearwardly in the rotating moving direction of the inner rotor as well as regulating the relative movement of the thread forwardly in the rotating moving direction, spins the thread without causing it to pass through the thread guide in the state that the rotational speed of the inner rotor is faster than the speed of the fiber bundle drawn out from the fiber collecting portion in thread piecing and introduces the thread into the thread guide by reducing the rotational speed of the inner rotor after it reaches the ordinary speed. When it is assumed that the inside diameter of the outer rotor in the fiber collecting portion is D, the rotational speed of the outer rotor is R 1 , the rotational speed of the inner rotor is R 2 and a spinning speed is V, it is preferable that the outer rotor and the inner rotor are driven to satisfy the relations πDR 2 > πDR 1 + V, when the thread is pieced and πDR 2 < πDR 1 + V, in the ordinary spinning. Contrary to the mentioned above, it is also possible that the guide member is disposed in the vicinity of the inlet of the thread guide of the inner rotor, formed in such a shape as to introduce the thread into the thread guide by permitting the relative movement of the thread guided from the fiber collecting portion to the thread drawing-out path without passing through the thread guide rearwardly in the rotating moving direction of the inner rotor as well as regulating the relative movement of the thread forwardly in the rotating moving direction, spins the thread without causing it to pass through the thread guide in the state that the rotational speed of the inner rotor is slower than the speed of the fiber bundle drawn out from the fiber collecting portion in thread piecing and introduces the thread to the thread guide by increasing the rotational speed of the inner rotor after it reaches ordinary speed. In the above contrary case, it is preferable that the outer rotor and the inner rotor are driven to satisfy the relations πDR 2 < πDR 1 + V, in the accelerated state of the inner rotor and the outer rotor when the thread is pieced, πDR 2 > πDR 1 + V, after the ordinary rotational speed is achieved, and πDR 2 < πDR 1 + V, in the ordinary spinning. According to the thread piecing apparatus, the navel to which the thread drawing-out path is formed is moved by the action of the moving means to the ordinary spinning position where the end surface on the inner rotor side of the navel can be engaged with a thread being drawn out through the thread guide and to the thread piecing position where it cannot be engaged with the thread. After a seed thread is connected to the fiber bundle collected in the fiber collecting portion by the action similar to the first aspect of the invention in the state that the navel is disposed at the thread piecing position, they are drawn out and spun to a thread. Thereafter, the navel is moved to the ordinary spinning position, that is, it is moved to a position where the end surface thereof is held in the recess formed to the inner rotor. Then, the thread rotatingly moves along the end surface of the inner rotor while the navel is being moved and is introduced into the thread guide when it reaches a position corresponding to the thread guide. It is preferable that the recess has a taper surface formed to the peripheral edge thereof. When the end surface of the navel advances into the recess of the inner rotor while the navel is being moved from the thread piecing position to the ordinary spinning position, the thread rotatingly moves along the taper surface of the inner rotor, thus the thread is smoothly introduced into the thread guide as well as the thread is prevented from being broken when it is introduced into the thread guide. It is preferable to form a guide recess to the end surface on the opening side of the inner rotor at a position nearer in rearward rotating moving direction of the inner rotor as compared with the thread guide so that the guide recess communicate to the thread guide. In the above arrangement, when the end surface of the navel advances into the recess of the inner rotor while the navel is being moved from the thread piecing position to the ordinary spinning position, the thread rotatingly moves along the end surface or the taper surface of the inner rotor, thus the thread is smoothly introduced into the thread guide through the guide recess. The moving means can be arranged such that it is operated by a thread piecing apparatus moving along the machine frame of an open end spinning frame including a plurality of spinning units. A thread piecing job at each spinning unit is automatically carried out by the thread piecing apparatus. The above moving means is operated by the thread piecing apparatus and the navel is moved to the thread piecing position and to the ordinary spinning position when the thread is pieced. It is preferable that the moving means includes a support member for supporting the navel, a lever extending in a direction perpendicular to the support member and engaged with the support member on the first end side thereof, urging means for urging the lever to a direction for holding the navel at the ordinary spinning position and the thread piecing apparatus includes operation means for pressing the lever against the urging means. In the thread piecing apparatus, since a drive unit for moving the navel to an evacuating position need not be provided with each spinning unit, the structure of the apparatus can be simplified. The lever is urged by the urging means in a direction for holding the navel at the ordinary spinning position. The operation means is actuated when a thread is pieced to thereby press the lever against the urging force of the urging means, so that the navel is disposed at the thread piecing position. When the pressure applied by the operation means is released, the lever is rotated by the urging force of the urging means, so that the navel is automatically disposed at the ordinary spinning position. Further, according to the present invention, the thread piecing apparatus further comprises the guide member disposed in the vicinity of the inlet of the thread guide of the inner rotor and which introduces the thread into the thread guide by permitting the relative movement of the thread guided from the fiber bundling or collecting portion to the thread drawing-out path without passing through the thread guide to rearwardly or forwardly in rotating moving direction of the inner rotor as well as regulating the relative movement thereof to the other of the rotating moving directions, means for detecting the rotation signal of the outer rotor, arithmetic operation means for calculating the rotational speed the outer rotor based on the signal detected by the rotational speed sensing means and control means for controlling the drive means so that the outer rotor and the inner rotor achieve predetermined rotational speeds. It is preferable that the guide member is formed such that the base end thereof is secured to the bottom of the groove forming the thread guide, wherein the guide piece is disposed at the portion projecting from the end surface on the opening side forwardly or rearwardly in the rotating moving direction of the inner rotor in order to guide a thread, which relatively moves toward the guide unit on the end surface on the opening side, to the extreme end side of the guide unit. Fibers fed in a separated state in the ordinary spinning are bundled to the fiber bundling portion of the outer rotor. The fiber bundle bundled in the fiber bundling portion is taken off therefrom and drawn out as a thread from the thread drawing-out path through the thread path of the inner rotor while being twisted. In the thread piecing, a seed thread is introduced into the outer rotor from the thread drawing-out path in the state that at least the outer rotor is rotated and after the extreme end of the seed thread reaches a position where it comes into contact with the fiber bundle in the fiber bundling portion, the fiber bundle in the fiber bundling portion is drawn out together with the seed fiber and a thread is spun without passing through the thread guide of the inner rotor. Then, after the rotational speeds of the outer rotor and the inner rotor reach the ordinary rotational speeds, the relative speed between the inner rotor and the fiber bundle is changed and the thread drawn out from the fiber bundling portion is introduced into the above fiber guide through the guide member. Thereafter, spinning is continuously carried out at the rotational speed in the ordinary spinning. FIG. 1 is a partial cross sectional view of an embodiment of an open end spinning frame according to the present invention; FIG. 2 is a front elevational view of an inner rotor; FIG. 3 is a cross sectional view of an inner rotor; FIG. 4 is a side elevational view of a navel moving means; FIG. 5 is a cross sectional view taken along the line V - V of FIG. 4; FIG. 6 is a partial cross sectional view showing the state that the navel is disposed at an evacuating position; FIG. 7 is a schematic side elevational view showing the relationship between a spinning unit and a thread piecing apparatus; FIG. 8 is a graph showing the change of the numbers of rotation of both the rotors when a thread is pieced; FIG. 9 is a block diagram of a controller; FIG. 10 is a flowchart showing actions carried out to piece a thread; FIG. 11 is a partial cross sectional view of a modification; FIG. 12A is a partial front elevational view of a modification of the inner rotor; FIG. 12B is a cross sectional view taken along the line XIIB - XIIB of FIG. 12A; FIG. 12C is a cross sectional view of another modification corresponding to FIG. 12B; FIG. 13 is a cross sectional view of a conventional apparatus; and FIG. 14 is a side elevational view of the inner rotor of the conventional apparatus. A preferred embodiment of the present invention will be described below with reference to FIG. 1 - FIG. 7. As shown in FIG. 1, an outer rotor 2 is secured to the extreme end of a hollow rotor shaft 1 as a rotary shaft so as to rotate integrally therewith, the rotor shaft 1 being rotatably supported on a machine frame in a known arrangement (for example, JP-A-5-33226, JP-A-6-123020 and the like) as well as driven in rotation by a drive means (any of them not shown). Bearings 3 are secured to the inside of both the ends (only one end is shown) of the rotor shaft 1 and a shaft 4 passing through the rotor shaft 1 is rotatably supported through the bearings coaxially with the rotor shaft 1. The shaft 4 has an inner rotor 5 secured at an end thereof so as to rotate therewith and the base end of the shaft 4 is abutted against a thrust bearing (not shown). The shaft 4 is driven in the same direction as the outer rotor 2 independently of the rotor shaft 1 or with a particular relationship therewith. As shown in FIG. 2, the inner rotor 5 is formed to a disk shape with a recess 7 formed at the center thereof which has a diameter larger than the maximum outside diameter of a navel 6 (refer to FIG. 1) and a recess 7a is formed to the peripheral edge of the opening of the recess 7 and a taper surface 7a is formed to the peripheral edge of the opening end of the recess 7. The inner rotor 5 is disposed in such a state that the end surface 5a of the outer rotor 2 one the opening side thereof is positioned nearer to the opening side of the outer rotor 2 as compared with a plane including a fiber collecting and bundling V-shaped portion (hereinafter, referred to as a fiber bundling portion) 2a formed in the maximum inside diameter portion of the outer rotor 2. A groove constituting a thread guide 8 from a position corresponding to the fiber bundling portion 2a to the recess 7 is formed to the inner rotor 5 in the state that the same side thereof as the opening of the outer rotor 2 is opened. As a guide unit through which the fiber bundle is introduced the thread guide 8, a guide member 9 is disposed forwardly of the rotational direction (clockwise direction of FIG. 2) of the inner rotor 5 at the inlet of the thread guide 8. The guide member 9 is disposed so that the end surface thereof projects beyond the end surface of the inner rotor 5. Further, an inclined surface 5b as a guide surface along the thread guide 8 is formed to the end surface 5a of the inner rotor 5 rearward of the rotational direction of the inner rotor 5 across the thread guide 8, that is, rearward of the thread rotatingly moving direction as well as a guide recess 5c as a guide surface communicating with the thread guide 8 is formed at a position corresponding to the side end portion of the taper surface 7a of the inclined surface 5b. The outside diameter of the inner rotor 5 is formed larger than the inside diameter of the opening of the outer rotor 2. Further, the outer rotor 2 is composed of two parts engaged with and secured to each other. As shown in FIG. 3, the guide member 9 is composed of a pin 9a having a diameter larger than the diameter of a thread y and a guide piece 9b inserted into the extreme end of the pin 9a. The guide piece 9b has a guide surface 9c formed thereto which is composed of a quarter arc surface along the outer periphery of the pin 9a on a side confronting the bottom of the thread guide 8 and a plane continuous to the arc surface and extending in the tangential direction thereof. The plane of the guide surface 9c is formed to extend in parallel with the longitudinal direction of the thread guide 8. Further, the guide piece 9b has an inclined surface 9d formed thereto the distance of which from the bottom of the thread guide 8 is increased toward rearward of the rotational direction of the inner rotor 5. The inclined surface 9d constitutes a guide surface located at a position forward of the thread rotatingly moving direction across the thread guide 8. The inclined surface 5b and the guide recess 5c located rearward of the thread rotatingly moving direction across the thread guide 8 are located nearer to an outer rotor drive unit as compared with the inclined surface 9d as the guide surface located forward of the thread rotatingly moving direction. A boss 11 is formed at the center of a housing 10 disposed at a position confronting the open side of the outer rotor 2 in the state that it projects into the outer rotor 2. A cylindrical support member 12 supporting the navel 6 is disposed at the center of the boss 11 coaxially with the inner rotor 5 so that it can vibrate in an axial direction. The cylindrical portion 6a of the navel 6 is engaged with and secured to the extreme end side of the support member 12. As shown in FIG. 4, a lever 14 is swingably supported between a pair of the support pieces 13a of a support bracket 13 secured to the housing 10 through a support shaft 15. As shown in FIG. 5, the lever 14 has a pair of engaging portions 14a extending along the longitudinal direction thereof and formed at the first end thereof and an accommodating unit 14b formed at the second end thereof, respectively. The lever 14 is disposed approximately perpendicularly to the support member 12 in the state that the engaging portion 14a thereof is engaged with an engaging groove 12a formed to the base end side of the support member 12 and the lever 14 is urged in a direction for holding the navel 6 at an ordinary spinning position by a coil spring 16 as an urging means accommodated in the accommodating unit 14b with an end thereof abutted against a support bracket 13. A leaf spring 17 extending to the second end side of the lever 14 is secured to the lever 14 integrally therewith. The support member 12, the lever 14, the coil spring 16 and the leaf spring 17 constitute a movement means for moving and disposing the navel 6 at the ordinary spinning position where the end surface of the navel 6 can be engaged with a fiber bundle F drawn out through the thread guide 8 and at a thread piecing position (evacuating position where the end surface of the navel 6 cannot be engaged with the fiber bundle F. A block 19 to which the base end of a yarn pipe 18 is secured is engaged with and secured to the base end of the support member 12. A path 19a is formed to the block 19 and the yarn pipe 18 extends while being bent so as to be secured to the path 19a. The yarn pipe 18 and the thread drawing-out path 19a also constitute a portion of the thread drawing-out path. An end of a fiber transportation path 20 for guiding fibers separated from each other by a combing roller (not shown) into the outer rotor 2 is opened to the peripheral surface of the boss 11. Further, a casing 21 covering the outer rotor 2 is disposed at a position confronting the housing 10 in the state that it is abutted against the end surface of the housing 10 through an O-ring 22. The casing 21 is connected to a negative pressure source (not shown) through a pipe 23. As shown in FIG. 7, a thread piecing apparatus 26 is provided with a frame base 25 including a multiplicity of spinning units 24 each having the device arranged as described above and moves along the longitudinal direction of the frame base 25 (in the direction perpendicular to the paper surface of FIG. 7). The thread piecing apparatus 26 stops at a position confronting the spinning unit 24 which requires thread piecing and carries out a thread piecing job. The thread piecing apparatus 26 includes an arm 27 as a operation means for pressing the above leaf spring 17 when the thread piecing operation is carried out. The arm 27 advances into a hole (not shown) formed to the cover of the spinning unit 24 so as to press the leaf spring 17. Next, operation of the apparatus arranged as described above will be described. The outer rotor 2 and the inner rotor 5 are driven in rotation in the same direction by the action of the drive means through the rotor shaft 1 and the shaft 4, respectively. The inner rotor 5 is rotated at a rotational speed similar to a speed at which the fiber bundle F is taken off from the fiber bundling portion 2a which is different from the rotational speed of the outer rotor 2 (a little faster than the rotational speed of the outer rotor 2). The fibers separated from each other by the action of the combing roller and fed into the outer rotor 2 from the fiber transportation path 20 in this state adhere to the inner wall surface 2b of the outer rotor 2 as well as slide along the inner wall surface 2b and bundled to the fiber bundling portion 2a as the maximum inside diameter portion. The fiber bundle F bundled to the fiber bundling portion 2a are connected to a thread Y drawn out by a drawing-out roller (not shown) through the yarn pipe 18 and taken off from the fiber bundling portion 2a as the thread Y is drawn out, thus the fiber bundle F is drawn out as the thread Y while being twisted by the rotation of the outer rotor 2. Twist applied to the thread Y and the fiber bundle F is transmitted up to the fiber bundling portion 2a of the outer rotor 2 from the base end 18a of the yarn pipe 18 as a starting point. In the ordinary spinning operation, the lever 14 is held at a position for disposing the navel 6 at the ordinary spinning position by the urging force of the coil spring 16 and the end surface 6c of the navel 6 advances into the recess 7 of the inner rotor 5, thus the navel 6 is located on the plane including the fiber bundling portion 2a. In this state, the fiber bundle F taken off from the fiber bundling portion 2a is introduced to the thread drawing-out path 6b through the thread guide 8 in the sate that it is in contact with the pin 9a of the guide member 9. Therefore, the angle between the direction in which the fiber bundle F is drawn out in the vicinity of a taking-off point (point where twist is applied) P and the fiber bundle F bundled to the fiber bundling portion 2a, that is, a twist application angel is made to an obtuse angle. Then, the difference of path of the fiber bundle F subjected to the twist while being taken off from the fiber bundling portion 2a between the inside and the outside thereof is reduced, thus the fiber bundle F is twisted by an approximately uniform force in the state that fibers are stretched straight. As a result, irregular portions are difficult to appear to the drawn-out thread and the feeling of sheet made by the thread will be improved. When one of the spinning units 24 requires thread piecing, the thread piecing apparatus 26 stops at a position corresponding to the spinning unit 24. Next, the arm 27 extends and is located at a thread piecing position where the leaf spring 17 is pressed by the arm 27, so that the leaf spring 17 is pressed to thereby rotate the lever 14 counterclockwise in FIG. 4. The rotation of the lever 14 permits the navel 6 to move in the axial direction of the inner rotor 5 together with the support member 12, thus the navel 6 is disposed at a thread piecing position where the end surface 6c thereof escapes from the recess 7 of the inner rotor 5 as shown in FIG. 6. Since the lever 14 receives the force of the arm 27 through the leaf spring 17, an unreasonable force does not act on the lever 14 and the support member 12 even if the position of the arm 27 is a little dislocated. Next, a seed thread is introduced into the outer rotor 2 through the yarn pipe 18 and the thread drawing-out path 6b in the state that the outer rotor 2 and the inner rotor 5 are rotated. The seed thread is introduced in the state that the rotational speeds of both the rotors 2, 5 are slower than the rotational speeds thereof in the ordinary spinning state. Since the end surface 6c of the navel 6 is held at the position where the navel 6c escapes from the recess 7 of the inner rotor 5, the seed thread reaches the fiber bundling portion 2a along the inner wall surface 2b after the extreme end of the seed thread easily reaches the inner wall surface 2b of the outer rotor 2. After the extreme end of the seed thread reaches a position where it comes into contact with the fiber bundle in the fiber bundling portion 2a, the seed thread is drawn out by the forward rotation of the not shown drawing-out roller so that the fiber bundle F bundled to the fiber bundling portion 2a is coiled around the end of the seed thread and drawn out together with the seed thread by being taken off from the fiber bundling portion 2a. Then, the thread Y is spun without passing through the thread guide 8 of the inner rotor 5 as shown in FIG. 6. Thereafter, when the rotational speeds of the outer rotor 2 and the inner rotor 5 reach the ordinary rotational speeds in ordinary spinning, the pressure aplied by the arm 27 is released and the lever 14 is turned clockwise in FIG. 4 by the urging force of the coil spring 16 so that the end surface 6c of the navel 6 advances into the recess 7 of the inner rotor 5 and the navel 6 returns the ordinary spinning position where it is disposed on the plane including the fiber bundling portion 2a. The end surface 6c of the navel 6 is engaged with the thread Y being spun while the navel 6 is moved and further when the navel 6 moves to the ordinary spinning position, the thread Y is pressed to the end surface 5a of the inner rotor 5 by being pressed to the end surface 6c. Then, when the rotational speed of the inner rotor 5 is made a little slower than the speed at which the fiber bundle F is taken off, the point P where the fiber bundle F is taken off is relatively moved forward of the rotational direction of the inner rotor 5. A portion of the thread Y rotatingly moves along the end surface 5a and the taper surface 7a of the recess 7 and when it reaches a position confronting the guide recess 5c and the inclined surface 5b, the thread y is introduced to the thread guide 8 along the guide recess 5c and the inclined surface 5b as well as introduced to the ordinary spinning position by being guided by the inclined surface 9d of the guide piece 9b. Then, spinning is transferred to the ordinary spinning in the state that the navel is held at the ordinary spinning position, so that the thread Y connected to the fiber bundle of the fiber bundling portion 2a moves into the thread guide 8 while in contact with the pin 9a and is drawn out from the thread taking-out path 6b as shown in FIG. 3. Since the inclined surface 5b is formed to extend along the thread guide 8 and the thread Y rotatingly moves in the state that it extends radially from the thread drawing-out path 6b as shown in FIG. 2, the thread Y is difficult to be introduced into the thread guide 8 only by the inclined surface 5b. However, since the guide recess 5c is formed in this embodiment, the thread Y is introduced into the guide recess 5c first as well as smoothly introduced into the thread guide 8 through the guide recess 5c and then smoothly introduced to the ordinary spinning position by being guided by the inclined surface 9d of the guide piece 9b. Since the taper surface 7a is formed to the peripheral edge of the recess 7 in this embodiment, the thread Y can be smoothly introduced into the thread guide 8. Further, since the peripheral edge of the recess 7 is not formed to an acute angle, the thread can be prevented from being cut off when it is introduced into the thread guide 8. Note, the same advantage can be achieved even if an arc surface is formed in place of the taper surface 7a. Since the end surface of the guide piece 9b projects beyond the end surface 5a of the inner rotor 5 in this embodiment, when the thread rotatingly moving on the end surface 5a reaches the position corresponding to the guide piece 9b, the thread Y can easily move to the inclined surface 9d side of the guide piece 9b, thus it can be easily introduced into the thread guide 8. In this embodiment, after the rotational speeds of the outer rotor 2 and the inner rotor 5 reach the ordinary rotational speeds in the ordinary spinning, the navel 6 is moved from the thread piecing position to the ordinary spinning position. Since the rotational speed of the outer rotor 2 is unstably synchronized with that of the inner rotor 5 before they reach the ordinary rotational speeds, the spinning state of the thread Y is also unstable. However, after the ordinary rotational speeds are reached, the spinning state of the thread Y is stabilized. Therefore, the thread Y is rotatingly moved up to the position corresponding to the thread guide 8 by being pressed to the end surface 5a of the inner rotor 5 and the taper surface 7a and securely introduced into the thread guide 8. Since the moving means for moving the navel 6 to the thread piecing position and the ordinary spinning position is operated by the arm 27 provided with the thread piecing apparatus 26 in this embodiment, a thread piecing job can be carried out without the assistant of the operator. Further, the lever 14 constituting the moving means urges the navel 6 to the ordinary spinning position through the coil spring 16 as the urging means in this embodiment. Consequently, when the operating force for pressing the lever 14 against the urging force of the coil spring 16 is released to hold the navel 6 at the thread piecing position, the navel 6 automatically returns to the ordinary spinning position. In addition, since the operating force for pressing the lever 14 is applied by arm 27 provided with the thread piecing apparatus 26, a drive unit for pressing the lever 14 need not be provided with each spinning unit 24. In the thread piecing method of the open end spinning frame shown in FIG. 1 - FIG. 7, it is preferable that the rotational speeds of the inner rotor and the outer rotor are easily controlled in the thread piecing and further operation can be easily transferred from the spinning state when a thread is pieced to the ordinary spinning state. FIG. 8 shows a controller 33 for controlling the drive of the outer rotor 2 and the inner rotor 5 in the aforesaid preferable state. The controller 33 includes a central processing unit (hereinafter, referred to as a CPU) 34 as an arithmetic operation means and a control means, a program memory 35 and a working memory 36. The CPU 34 is connected to first and second sensors 42, 43 through an I/O interface 37 as well as to an inverter 44 through the I/O interface 37 and a drive circuit 38. Further, the CPU 34 is connected through a drive circuit 40 to an inverter 39 having a motor M connected thereto. The program memory 35 is composed of a read only memory (ROM) and stores a thread piecing operation program and the like. The working memory 36 is composed of a random access memory (RAM) and temporarily stores data input from an input unit 41, data arithmetically processed by the CPU 34, and the like. The CPU 34 controls the drive motor M and a motor 45 so that the rotational speeds of both the rotors 2,5 are set to predetermined rotational speeds corresponding to the spinning conditions input from the input unit 41. The CPU 34 calculates the rotational speed of the outer rotor 2 based on a signal output from the first sensor 42 and calculates the rotational speed of the inner rotor 5 corresponding to the above rotational speed. Then, the CPU 34 controls the motor 45 so that the above rotational speed is achieved. That is, the CPU 34 controls the rotational speed of the inner rotor 5 based on the rotational speed of the outer rotor 2. Next, operation of the apparatus arranged as described above will be described with reference to FIG. 1 and FIG. 9. The outer rotor 2 of each spindle is driven through a drive belt (not shown) which is in contact with the rotor shaft 1 through a driving relationship, the motor 45 is driven at a predetermined speed based on the rotational speed of the outer rotor 2 and the inner rotor 5 is driven at a predetermined speed in the same direction as that of the outer rotor 2. When it is assumed that the diameter of the fiber bundling portion 2a is D, the number of rotation of the outer rotor 2 is R 1 , the number of rotation of the inner rotor 5 is R 2 and a spinning speed is V, the inner rotor 5 is driven at a speed which satisfies πDR 2 < πDR 1 + V and is a little slower than a speed at which the fiber bundle F is taken off from the fiber bundling portion 2a (a speed a little faster than the rotational speed of the outer rotor 2). Fibers separated from each other by the action of the combing roller and fed from the fiber transportation path 20 into the outer rotor 2 in this state adhere to the inner wall surface of the outer rotor 2 as well as slide along the inner wall surface and are bundled to the fiber bundling portion 2a as the maximum inside diameter portion. The fiber bundle bundled to the fiber bundling portion 2a is connected to the thread Y drawn out by the drawing-out roller (not shown) through the yarn pipe 18 and taken off from the fiber bundling portion 2a as the thread Y is drawn out and then drawn out while being twisted as the thread Y. The twist applied to the thread Y and the fiber bundle is transmitted up to the fiber bundling portion 2a from the end of the yarn pipe 18 as a starting point. The CPU 34 calculates the rotational speed of the outer rotor 2 based on the signal output from the first sensor 42 and calculates the rotational speed of the inner rotor 5 corresponding to the above rotational speed. Then, the CPU 34 outputs a command signal for rotating the inner rotor 5 at the rotational speed to the inverter 44. The inverter 44 drives the motor 45 based on the command signal from the CPU 34. Then, the inner rotor 5 is driven at the predetermined rotational speed corresponding to the rotational speed of the outer rotor 2. The rotational speed of the shaft 4 is detected by the second sensor 43 and fed back to the CPU 34. Next, thread piecing operation will be described with reference to the flowchart of FIG. 10. Thread piecing starts in the state that the outer rotor 2 is stopped by a brake and the rotation of the inner rotor 5 is also stopped. First, the not shown drawing-out roller is reversed to thereby feed the seed thread into the yarn pipe 18 a predetermined length at step S1. Next, the brake of the outer rotor 2 is released to rotate the outer rotor 2 as well as the motor 45 is driven to thereby rotate the inner rotor 5 at step S2. The CPU 34 controls the motor 45 based on the signal output from the first sensor 42 so that the inner rotor 5 is rotated at a rotational speed satisfying πDR 2 > πDR 1 + V. Then, the inner rotor 5 is driven so that the number of rotation thereof is larger than that of the outer rotor 2 at all times as shown in FIG. 8. After the rotational speeds of both the rotors 2, 5 reach first predetermined rotational speeds which are slower than those in the ordinary spinning, separated fibers start to be fed as well as a seed thread is introduced into the outer rotor 2 at step S3. After the extreme end of the seed thread reaches a position where it comes into contact with a fiber bundle in the fiber bundling portion 2a, the seed thread is drawn out by the forward rotation of the drawing-out roller at step S4, the fiber bundle F bundled to the fiber bundling portion 2a is coiled around the end of the seed thread, taken off from the fiber bundling portion 2a and drawn out together with the seed thread. Then, a thread Y is spun without passing through the thread guide 8 of the inner rotor 5 (FIG. 2). Since the rotational speed of the inner rotor 5 is faster than the taking-off speed of the thread Y in this state, the thread Y extending from the fiber bundling portion 2a to the thread drawing-out path 19a relatively moves rearward of the rotational direction of the inner rotor 5 with respect to it. The CPU 34 determines whether or not the outer rotor 2 and the inner rotor 5 reach the ordinary rotational speeds in the ordinary spinning at step S5 and when they reach them, the process goes to step S6 where the CPU 34 controls the motor 45 so that the rotational speed of the inner rotor 5 is made slower than the taking-off speed of the thread Y. As a result, the thread Y extending from the fiber bundling portion 2a to the thread drawing-out path 19a relatively moves forward of the rotational direction of the inner rotor 5. Then, the thread Y is guided by the thread guide 8 and introduced to the ordinary spinning position by being guided by the inclined surface 9d of the guide member 9. Thereafter, operation is transferred to the ordinary spinning and the thread Y connected to the fiber bundle F of the fiber bundling portion 2a moves in the thread guide 8 while in contact with the pin 9a and is drawn out from the thread drawing-out path 19a. In the ordinary spinning, both the rotors 2, 5 satisfy πDR 2 < πDR 1 + V, so that the inner rotor 5 is rotated at a rotational speed equal to the taking-off speed of the fiber bundle. As described above, when the thread is pieced, it suffices only to drive the inner rotor 5 at a speed to permit the thread Y extending from the fiber bundling portion 2a to the thread drawing-out path 19a to relatively move with respect to the rotational direction of the inner rotor 5, that is, at a speed different from the speed at which the thread Y is drawn out. Therefore, even if the rotational speed of the inner rotor 5 is varied a little, since it satisfies the condition that it is different from the drawing-out speed of the thread Y, the motor 45 can be easily controlled. Further, since the thread Y is introduced into the thread guide 8 by changing the relationship between the rotational speed of the inner rotor 5 and the rotational speed of the outer rotor 2 after both the rotors 2, 5 reach the ordinary rotational speeds, that is, in the state that the thread Y is stably spun, the thread Y is smoothly introduced into the thread guide 8. This embodiment has the following advantages in addition to the above ones. (a) In the thread piecing, the thread Y is spun without passing through the thread guide 8 in the state that the rotational speed of the inner rotor 5 is faster than the speed of the fiber bundle F (thread Y) drawn out from the fiber bundling portion 2a and after the rotational speed of the inner rotor 5 reaches the ordinary speed, the rotational speed thereof is lowered and the thread is introduced into the thread guide 8. Thus, the relationship πDR 2 > πDR 1 + V employed when the thread is pieced can be easily transferred to the relationship πDR 2 < πDR 1 + V in the ordinary spinning only by reducing the rotational speed of the inner rotor 5 to the predetermined speed in the speed change effected after the ordinary speed is reached. (b) Even if the rotational speed of the outer rotor 2 is made unstable by the slip caused between the aforesaid drive belt (not shown) and the rotor shaft 1, since the rotational speed of the inner rotor 5 is controlled based on the rotational speed of the outer rotor 2, both the rotors 2, 5 can be easily synchronized with each other. Further, since the shaft 4 of the inner rotor 5 also serves as the drive shaft of the motor 45, the synchronization of both the rotors 2, 5 can be more easily controlled. Note, the present invention is not limited to the above embodiment but may be embodied, for example, as described below. (1) As shown in FIG. 11, a step portion 28a is formed to the inner surface of an outer rotor 2 at a portion lower than a fiber bundling portion 2a so that the step portion 28a has a smaller diameter on the bottom side thereof as well as a step portion 28b is formed to a position of the outer periphery of an inner rotor 5 which corresponds to the step portion 28a. In this case, since the step portions 28a, 28b act as a labyrinth, short fibers and the like are prevented from entering the bottom side of the outer rotor 2 from a gap between the outer rotor 2 and the inner rotor 5, thus a bearing 3 supporting a shaft 4 is prevented from being clogged with fiber dusts. Further, a labyrinth may be disposed between the bottom of the outer rotor 2 and the bottom of the inner rotor 5 in place of the step portions 28a, 28b. (2) As shown in FIGS. 12A and 12B, a guide member 9 is composed a pin 9a only and the head portion thereof has a taper surface 9e formed such that the diameter of the head portion is increased toward the extreme end thereof as compared with the portion thereof corresponding to the inclined surface 5b of an inner rotor 5. Further, an inclined surface 9f is formed to the head portion which extends from an end in a recess 7 located forward of the rotational direction of the inner rotor 5 toward rearward of the rotational direction. In this case, a navel 6 is also moved from the thread piecing position to the ordinary spinning position in the state that the thread Y is spun without passing through a thread guide 8 as well as when the rotational speed of the inner rotor 5 is made slower than a moving speed at a taking-off point, the thread Y rotatingly moves on an end surface 5a and then is introduced into the spinning position in the thread guide 8 by being guided by the taper surface 9e. The existence of the taper surface 9f prevents the possibility that the thread Y is caught by the pin 9a and broken even if the thread Y relatively moves rearward of the rotational direction of the inner rotor 5 in the state that the thread Y is spun without passing through the thread guide 8. (3) Further, a pin 9a to which a taper surface 9e is formed at the intermediate portion thereof to increase the diameter of the extreme end of the pin may be used as shown in FIG. 12C. (4) A guide member 9 is not formed separately from an inner rotor 5 but the portion thereof having a shape corresponding to a pin 9a formed to one of the above respective shapes may be formed integrally with the inner rotor 5. (5) An arm 27 may directly press a lever 14 by the omission of a leaf spring 17 constituting the moving means of a navel 6. (6) An operating member may be disposed on a spinning unit 24 side to move a navel 6 to an evacuating position by pressing a leaf spring 17 or a lever 14 when a thread is pieced. For example, an air cylinder or the like is disposed at such a position that when the piston rod thereof is projected, it is engaged with the leaf spring 17 or the lever 14 to thereby move the navel 6 to a thread piecing position. A switch for operating the air cylinder is disposed to the outside of the spinning unit 24. The thread piecing apparatus 26 moves the navel 6 to the thread piecing position and an ordinary spinning position through an arm 27 by operating the switch. In this arrangement, the operator can also easily piece a thread by operating the switch. (7) A device disclosed in JP-A-6-123020 may be employed as a means for moving a navel 6. That is, the cylindrical portion 6a of the navel 6 is inserted into a cylindrical support member 12 having a guide hole and an engaging portion passing through the guide hole is projected from the outer surface of the base end of the cylindrical portion 6a and when the engaging portion is rotated on the cylindrical portion 6a by a rotary solenoid, the navel 6 is moved in an axial direction. The switch of the rotary solenoid is disposed to the outside of a spinning unit 24. The thread piecing apparatus 26 is arranged such that the navel 6 is moved to a thread piecing position and an ordinary position by operating the switch. The operator can piece a thread through an arm 27 by operating the switch also in this case. (8) A spring such as a leaf spring or the like may be used as an urging means for urging a navel 6 to an ordinary spinning position. (9) An air hole for communicating the bottom of (10) An air hole for communicating the bottom of the fiber bundling portion 2a of an outer rotor 2 with the outer periphery of the outer rotor 5 may be formed. Since there is generated an air flow from the inside of the outer rotor 2 toward the outer periphery thereof through the air hole in this case, a force acts to press a fiber bundle F bundled to the fiber bundling unit 2 to the bottom thereof, so that twist is difficult to be transmitted to a fiber bundle in the fiber bundling portion 2a. (10) A self-exhausting hole may be formed to an outer rotor 2. A lever has a leaf spring secured thereto and an operating means is engaged with the leaf spring and transmits a pressure to the lever. In this case, even if the stroke of the operating means is not accurately set, the application of an unreasonable force to the lever and the like can be prevented.

Claims: A thread piecing method in an open end spinning frame having an outer rotor (2) including a fiber collecting portion (2a) to which fibers fed in a separated state are collected, and an inner rotor (5) which is disposed in the outer rotor (2) coaxially thereto and which defines a thread guide (8) for guiding a thread (Y) drawn out from the fiber collecting portion (2a) by means of a guide member (9) to the end of a thread drawing-out path (6b), which guide member (9) is disposed there forwardly in the rotating moving direction, extends from the bottom of said thread guide (8) and projects beyond the end surface (5a) of said inner rotor (5), wherein the inner rotor (5) is positively driven independently of the outer rotor (2) to piece the thread by moving a navel (6) disposed at the end of the thread drawing-out path nearer to the open end side of the outer rotor (2) as compared with an ordinary spinning position when the thread is pieced and thereafter the navel (6) is returned to the ordinary spinning position, comprising the steps of: moving said navel (6) to a thread piecing position when the thread is pieced; introducing a seed thread from said thread drawing-out path (6b) into said outer rotor (2) in the state that said outer rotor (2) is rotated; causing the extreme end of the seed thread to reach a position where it comes into contact with a fiber bundle in said fiber collecting portion (2a); drawing the fiber bundle in said fiber collecting portion (2a) together with the seed thread from said thread drawing-out path (6b) without causing them to pass through the thread guide (8) of said inner rotor (5) and spinning them after the extreme end of the seed thread reaches the position; moving said navel (6) to the ordinary spinning position side thereafter; and introducing said thread (Y) into said thread guide (8), characterized in that said thread is guided into said thread guide (8) by guide surfaces (5b, 5c) located on a wall surface of said thread guide (8) rearwardly in the rotating moving direction and being recessed in closed end direction of said inner rotor (5) with respect to an end surface in open end direction of said guide member (9), and guided by a guide piece (9b) being formed on an extreme end of said guide member (9), in order to guide said thread relatively moving toward said guide member (9) on the end surface in the open end direction to the extreme end side of said guide member (9). A thread piecing method according to claim 1, characterized in that the seed thread is introduced at a speed lower than an ordinary rotational speed of said outer rotor (2) and said inner rotor (5) at said seed thread introducing step and said navel (6) is moved from the thread piecing position to the ordinary spinning position at said navel moving step after said outer rotor (2) and said inner rotor (5) reach the ordinary rotational speeds in the ordinary spinning. A thread piecing method according to claim 1, characterized in that said fiber bundle drawing out and spinning step is carried out by setting a rotational speed of said inner rotor (5) to a speed different from the speed of the fiber bundle drawn out from said fiber collecting portion (2a) and said step of introducing the thread into said thread guide is carried out by changing the relative speed between said inner rotor (5) and said fiber bundle after the rotational speeds of the outer rotor (2) and the inner rotor (5) reach the ordinary speeds and introducing the fiber bundle through said guide member (9). A thread piecing method according to claim 3, characterized in that the relative speed is changed by changing the rotational speed of said inner rotor (5). A thread piecing method according to claim 3, characterized in that the relative speed is changed by changing the speed of at which the fiber bundle is drawn out. A thread piecing method according to claim 3, characterized in that said guide member (9) is disposed in the vicinity of the inlet of said thread guide (8) of said inner rotor (5), formed in such a shape as to introduce the thread (Y) into said thread guide (8) by permitting the relative movement of the thread (Y) guided from said fiber collecting portion (2a) to said thread drawing-out path (6b) without passing through said thread guide (8) rearwardly in the rotating moving direction of said inner rotor (5) as well as regulating the relative movement of the thread (Y) forwardly in the rotating moving direction, spins the thread (Y) without causing it to pass through said thread guide (8) in the state that the rotational speed of said inner rotor (5) is faster than the speed of the fiber bundle drawn out from said fiber collecting portion (2a) in thread piecing and introduces the thread (Y) into said thread guide (8) by reducing the rotational speed of said inner rotor (5) after it reaches the ordinary speed. A thread piecing method according to claim 6, characterized in that when it is assumed that the inside diameter of said outer rotor (2) in said fiber collecting portion (2a) is D, the rotational speed of said outer rotor (2) is R 1 , the rotational speed of said inner rotor (5) is R 2 and a spinning speed is V, said outer and inner rotors are driven to satisfy the relations πDR 2 > πDR 1 + V, when the thread is pieced and πDR 2 < πDR 1 + V, in the ordinary spinning. A thread piecing method according to claim 3, characterized in that said guide member (9) is disposed in the vicinity of the inlet of said thread guide (8) of said inner rotor (5), formed in such a shape as to introduce the thread (Y) into said thread guide (8) by permitting the relative movement of the thread (Y) guided from said fiber collecting portion (2a) to said thread drawing-out path (6b) without passing through said thread guide (8) rearwardly in the rotating moving direction of said inner rotor (5) as well as regulating the relative movement of the thread (Y) forwardly in the rotating moving direction, spins the thread (Y) without causing it to pass through said thread guide (8) in the state that the rotational speed of said inner rotor (5) is slower than the speed of the fiber bundle drawn out from said fiber collecting portion (2a) in thread piecing and introduces the thread (Y) to said thread guide (8) by increasing the rotational speed of said inner rotor (5) after it reaches ordinary speed. A thread piecing method according to claim 8, characterized in that when it is assumed that the inside diameter of said outer rotor (2) in said fiber collecting portion (2a) is D, the rotational speed of said outer rotor (2) is R 1 , the rotational speed of said inner rotor (5) is R 2 and a spinning speed is V, said outer rotor and said inner rotor are driven to satisfy the relations πDR 2 < πDR 1 + V, in the accelerated state of said inner rotor and said outer rotor when the thread is pieced, πDR 2 > πDR 1 + V, after the ordinary rotational speed is achieved, and πDR 2 < πDR 1 + V, in the ordinary spinning. A thread piecing apparatus of an open end spinning frame having means for partitioning an outer rotor (2) including a fiber collecting portion (2a) to which fibers fed in a separated state are bundled and an opening and a thread drawing-out path (6b), an inner rotor (5) which is disposed in the outer rotor (2) coaxially therewith and includes a thread guide (8) formed thereto for guiding a thread (Y) drawn out from the fiber collecting portion (2a) by means of a guide member (9) to the end of the thread drawing-out path (6b) which guide member (9) is disposed there forwardly in a rotating moving direction, extends from the bottom of the thread guide (8) and projects beyond the end surface (5a) of said inner rotor (5), means (M, 45) for positively driving said outer rotor (2) and said inner rotor (5) independently of each other and a navel (6) disposed movably to the end of the thread drawing-out path (6b) wherein, when said thread (Y) is pieced, the thread (Y) is pieced by moving the navel (6) nearer to the open end side of the outer rotor (2) as compared with an ordinary spinning position and thereafter the navel (6) is returned to the ordinary spinning position, comprising moving means (12 - 17) for moving said navel (6) in axial direction between the ordinary spinning position and the thread piecing position wherein said inner rotor (5) includes a recess (7) formed at a position corresponding to said navel (6), characterized in that said thread is guided into said thread guide (8) by guide surfaces (5b, 5c) located on a wall surface of said thread guide (8) rearwardly in the rotating moving direction and being recessed in closed end direction of said inner rotor (5) with respect to an end surface in open end direction of said guide member (9), and guided by a guide piece (9b) being formed on an extreme end of said guide member (9), in order to guide said thread relatively moving toward said guide member (9) on the end surface in the open end direction to the extreme end side of said guide member (9). A thread piecing apparatus according to claim 8, characterized in that said recess (7) has a taper surface (7a) formed to the peripheral edge thereof. A thread piecing apparatus according to claim 10 or 11, characterized in that the end surface on the opening side of said inner rotor (5) has a guide recess (5c) formed thereto which is located nearer in rearward rotating moving direction of said inner rotor (5) as compared with said thread guide (8) and communicates to said thread guide (8). A thread piecing apparatus according to any of claims 10 to 12, characterized in that said moving means (12 - 17) are arranged so as to be operated by a thread piecing apparatus (26) moving along a frame base (25) of an open end spinning frame including a plurality of spinning units (24). A thread piecing apparatus according to claim 13, characterized in that said moving means (12 - 17) includes a support member (12) for supporting said navel (6), a lever (14) extending in a direction perpendicular to said support member (12) and engaged with said support member (12) on the first end side thereof, urging means (16) for urging said lever (14) to a direction for holding said navel (6) at the ordinary spinning position and said thread apparatus (26) includes operation means (27) for pressing said lever (14) against said urging means (16). A thread piecing apparatus according to claim 10, characterized in that said guide member (9) is disposed in the vicinity of the inlet of said thread guide (8) of said inner rotor (5) and introduces the thread (Y) into said thread guide (8) by permitting the relative movement of the thread (Y) guided from said fiber collecting portion (2a) to said thread drawing-out path (6b) without passing through said thread guide (8) rearwardly or forwardly in the rotating moving direction of said inner rotor (5) as well as regulating the relative movement thereof to the other of the rotating moving directions, rotational speed sensing means (42) for detecting a rotation signal of said outer rotor (2), arithmetic operation means (34) for calculating the rotational speed of said outer rotor (2) based on the signal detected by said rotational speed sensing means (42) and control means (33, 34) for controlling said drive means (M, 45) so that said outer rotor and said inner rotor achieve predetermined rotational speeds. A thread piecing apparatus according to claim 15, characterized in that said guide member (9) is arranged such that the base end thereof is secured to the bottom of a groove for forming said thread guide (8), wherein said guide piece (9b) is formed at the portion projecting from the end surface on the opening side forwardly or rearwardly in the rotating moving direction of said inner rotor (5). A thread piecing apparatus according to claim 10, characterized in that said urging means is a coil spring (16) and said operation means is a leaf spring (27). A thread piecing apparatus according to claim 10, characterized in that a prevention means for preventing the passage of short fibers and the like is disposed at a position nearer to the bottom of said outer rotor as compared with said fiber bundling unit between the inner surface of said outer rotor (2) and the outer surface of said inner rotor (5). A thread piecing apparatus according to claim 18, characterized in that said prevention means (28) is composed of an annular projecting step portion (28a) formed to the inner periphery of said outer rotor (2) and an annular concaving step portion (28b) formed to the outer periphery of said inner rotor (5). A thread piecing apparatus according to claim 19, wherein said prevention means (28) is a labyrinth seal disposed between the inner surface of the bottom of said outer rotor (2) and the outer surface of the bottom of said inner rotor (5). A thread piecing apparatus according to claim 15, characterized in that said guide member (9) is composed of a pin (9a) having a diameter larger than the diameter of the thread (Y) and said guide piece (9b) is attached to the extreme end of said pin (9a) such that the end surface of said guide piece (9b) projects from the end surface of said inner rotor (5). A thread piecing apparatus according to claim 15, characterized in that said guide member (9) is composed of a pin (9a) and the head portion of said pin (9a) is formed to have a taper surface (9e) so that the diameter of the head portion is increased toward the extreme end side thereof as compared with the portion thereof corresponding to the inclined surface formed to said inner rotor (5) and in that an inclined surface (9f) is formed at the head portion which extends from an end located in said recess (7) forwardly in the rotating moving direction of said inner rotor (5) in rearward rotating moving direction. A thread piecing apparatus according to claim 15, characterized in that said guide member (9) is formed integrally with said inner rotor (5). A thread piecing apparatus according to claim 15, characterized in that said guide member (9) is formed separately from said inner rotor (5).

Inventors: MORISHITA TOSHIO, SAKAKIBARA ATSUO, MORISHITA, TOSHIO, SAKAKIBARA, ATSUO, Morishita, Toshio, c/o K.K. Toyoda, Sakakibara, Atsuo, c/o K.K. Toyoda
Applicants: KK, KABUSHIKI KAISHA
Application year: 1996
Main classification: D01H4
IPC codes: D01H4