Method and apparatus for piecing slivers in a spinning machine

Abstract: A sliver piecing unit 80 includes three sets of separable rollers 804 and 844, 806 and 846, and 808 and 848 for nipping a sliver S1 fed from a consumed can to a spinning machine. A throttling nozzle 870 is arranged between the second and third sets of rollers 806 and 846, and 808 and 848. The draft ratio between the first and second sets of rollers 804 and 844, and 806 and 846 can be varied between 1.0 and 2.0. A sliver feed unit 70 includes a separable first and second roller 702a and 702b for feeding a sliver S2 from a full can to the piecing unit 80 so that the slivers S1 and S2 are combined. The draft ratio between the first and second sets of rollers 804 and 844, and 806 and 846 is controlled to obtain combined slivers of a thickness corresponding to that of a single sliver. A nipping belt 884 and nipping roller 886 are provided at the outlet from the third set of the rollers 808 and 804 for obtaining a rubbing movement in the combined slivers. A breaking element 802 is provided at the inlet to the first set of the rollers 804 and 844 to break the first sliver S1 after the completion of the piecing operation.

Description: The present invention relates to a method and apparatus according to the preamble of claim 1 and 6, respectively. EP-A-361 306 discloses an automatic apparatus for piecing a sliver from a full can to a sliver which is fed from a consumed can to a roving frame. In this prior art apparatus, the piecing of slivers is executed when the spinning operation of the sliver is stopped. Namely, first, the sliver from the consumed can to the corresponding drafting unit of the roving frame is broken. Then, the broken end from the drafting unit is, at a piecing unit, superimposed with an end of a sliver from the full can. The piecing unit is, then, operated for piecing the superimposed ends of the sliver. Such a piecing operation is repeated for all of the cans of the roving unit. After the completion of the piecing operation for all of the cans of the roving frame, a spinning operation by the roving frame is re-started. JP-A-04 049 176 discloses an automatic piecing unit wherein the end from the drafting unit of a roving frame and the end from a full can are nipped by a nipping means, so that the superimposed ends are interwound by imparting air flows. In JP-A-3-232669, spikes are provided for causing the fibers between the combined slivers to be interwound. Furthermore, EP-A-481 922 which represents the closest prior art discloses a system for an automatic piecing of slivers in a textile machine, such as a roving frame, wherein it has a sliver piecing assembly having a plurality of sets of opposite, separable draft rollers and a set of separable rubbing rollers at an outlet side of the draft rollers for holding a first old sliver between the opposite rollers. The system is further provided with a sliver feed assembly having an opposite, separable set of feed rollers for holding a second sliver therebetween. The first sliver from a can which is emptied or nearly emptied is held by the opposite rollers of the piecing assembly, and the first sliver is cut between the piecing assembly and the can, in such a manner that a sufficient length of the sliver exists on the inlet side of the piecing assembly to obtain a desired piecing operation. Then, a feeding operation of the first sliver is commenced by rotating the rollers, while a feeding operation of the second sliver from a full can by means of the feeding assembly is also commenced so that a front end of the second assembly is introduced into the inlet side of the piecing assembly so that the second sliver from the can is combined with the first sliver from the can which is nearly emptied. When the combined first and second slivers reach the drafting rollers of the piecing assembly, a draft ratio by the drafting rollers, which is a ratio of the rotational speed of the outlet side draft rollers to those of the inlet side draft roller, is changed from a value of 1.0 to 2.0, so that the thickness of the combined sliver is reduced to the thickness corresponding to that for a single sliver, when the combined sliver is moved out of the outlet side drafting rollers. Furthermore, at the outlet side of the draft rollers, the combined slivers are subjected to a rubbing movement by the rubbing rollers which are rotated in opposite directions for feeding the sliver while being oppositely axially reciprocated, which allows the combined slivers to be interwound with each other to provide a complete single sliver. In the prior arts, the piecing operation of the slivers are done when a feeding of a sliver to the roving frame is interrupted, which makes it impossible to execute the piecing operation when the roving frame is operated. Thus, in order to execute the sliver piecing operation, the spinning operation is interrupted, which reduces the production efficiency of a spinning factory. In the prior arts, fibers are only insufficiently interwound between the combined slivers, which causes a defect to be created at the pieced portion of the sliver, which frequently causes the sliver to be broken at a following spinning process. Furthermore, in the prior arts, the thickness of the pieced portion of the sliver is apt to be rapidly increased from a thickness of a single sliver, which causes the combined sliver to become uneven, which causes the quality of the pieced portion to be worsened, thereby sliver to be easily broken at a subsequent process. An object of the present invention is to provide a method and apparatus for piecing slivers in which the sliver piecing is executed without stoppage of a spinning machine and which are capable of obtaining an improved quality at the pieced portion of the slivers and of obtaining an improved interwound condition of fibers between combined ends of the slivers. This object is achieved by the features of the characterizing portion of claim 1 and 6, respectively. BRIEF DESCRIPTION OF ATTACHED DRAWINGS Figs. 1-(a) to (h) are schematic views of a piecing apparatus according to the present invention at series of phases during the execution of a piecing operation of slivers. Fig. 2 is a schematic plan view of a system for conveying cans for slivers from a roving frame to a flyer frame. Figs. 3-(a) and (b) show, schematically, a sliver piecing operation at different phases, respectively. Figs. 4-(a) and (b) show, schematically, a sliver end drafting operation at different phases, respectively. DESCRIPTION OF PREFERRED EMBODIMENTS Fig. 1 shows schematically the principle of piecing slivers according to the present invention. Provided is a first or lower roller assembly constructed by a rollers Ia, IIIa and IVa and a nipping belt Va, and a second or upper roller assembly constructed by a rollers Ib, IIIb and IVb and a nipping roller Vb. In a condition (a), the first and the second assemblies are separated from each other. The first roller assembly is further provided with a nozzle II as a means for collecting fibers, arranged between the rollers Ia and IIIa. The nozzle II forms a slit II' on its one side facing the upper roller assembly. In a condition (b), a sliver S 1 to be pieced is introduced into the space between the first and second roller assemblies so that the sliver is in contact with the rollers Ia, IIIa and IVa, and is introduced into the nozzle II via the slit II'. In a condition in Fig. 1 (c), the upper roller assembly is moved downwardly, so that opposite sets of the rollers Ia and Ib, IIIa and IIIb, and IVa and IVb are contacted with each other so that the sliver S 1 is nipped between the opposite rollers. A draft means is constructed by the sets of opposite rollers IVa and IVb, and IIIa and IIIb. A draft ratio which is ratio of the surface speed of the set of the opposite rollers IIIa and IIIb to the surface speed of the set of the opposite rollers IVa and IVb is variable between 1.0 and 2.0. No draft is, basically, generated between the sets of the rollers IIIa and IIIb, and Ia and Ib, and therefore, the surface speed of the opposite set of the roller Ia and Ib is always equalized to that of the opposite set of the rollers IIIa and IIIb. As shown in Fig. 1-(d), a sliver feed means is constructed by a set of opposite apron rollers VIa and VIb for feeding a second sliver S 2 which is to be pieced to the first sliver S1. The second sliver S 2 is fed to the opposite set of the rollers IVa and IVb so that the sliver S 2 is combined with the sliver S 1 . As mentioned above, the draft ratio of the sets of the rollers IVa and IVb, and IIIa and IIIb, which construct the draft means, is usually set to 1.0. But, at a time when the leading end of the combined sliver has just come to a desired location between the roller sets IVa and IVb, and IIIa and IIIb, the draft ratio is increased to a value of 2.0. Namely, the peripheral speed of the upstream set of the rollers IVa and IVb is reduced to a half of that of the downstream set of the rollers IIIa and IIIb. As a result, the thickness of the combined slivers are reduced to that of a single, complete sliver as it should be when it comes out from the upstream set of the draft rollers IIIa and IIIb. It should be noted that, in place of the 1/2 reduction of the speed of the upstream set of the draft rollers IVa and IVb, the speed of the downstream set of the draft rollers IIIa and IIIb can be doubled, so that the draft of 2.0 is, also, obtained between the upstream set of the rollers IVa and IVb, and the downstream set of the rollers IIIa and IIIb. As shown in Fig. 1-(e), the combined slivers are, at the collecting nozzle II, subjected to a lateral force which causes the combined slivers S 1 and S 2 to be interwound with each other to a complete single sliver. In addition, the sliver coming out from the opposite rollers Ia and Ib is subjected to a rubbing movement by the rubbing roller Vb which is rotated and which is axially reciprocated while contacting with the flexible belt Va. The flexibility of the belt Va allows the sliver to contact with the roller Vb along a certain range of its outer periphery. In other words, the nipping of the sliver between the belt Va and the roller Vb takes place along a length in the direction of the supply of the sliver. As a result, an effective rubbing movement is applied to the sliver, causing the slivers S 1 and S 2 to be effectively interwound with each other to produce a single complete sliver. As shown in Fig. 1-(f), a sliver breaking member VII, which is usually at a retracted position, is moved in a direction as shown by an arrow, while the feed roller VIa is moved toward the sliver breaking member VII to a position as shown in Fig. 1-(g), where the feed rollers VIa is, at its outer surface, contacted with the sliver breaking member VII via the first sliver S 1 , which causes the fibers to be separated with each other, which causes the sliver S 1 to be broken. The member VII is, at its outer periphery, formed with a plurality of grooves, so that the sliver S 1 is partially gripped along the width of the sliver S 1 , so that the separation of the fibers is sparsely done, so that an increased length of an end portion of the sliver of reduced number of fibers can be obtained. In place of using the sliver breaking member VII, other means for breaking the sliver can be employed, such as a nipping member for nipping the sliver or a sucking nozzle for sucking the sliver. At a final stage of the sliver piecing operation according to the present invention, the speed of the upstream set of the draft rollers IVa and IVb is doubled, so that the speed of the rollers IVa and IVb is equalized to that of the downstream set of the draft roller IIIa and IIIb, when the broken end of the first sliver S 1 has just come to a desired location between the sets of the rollers IIIa and IIIb, and IVa and IVb. Namely, no draft is now applied to the sliver at the drafting means, thereby maintaining the desired thickness of the sliver. In Fig. 1-(h), it is shown that the upper assembly (Ib, IIIb, IVb and Vb) is separated from the lower assembly (Ia, II, IIIa, IVa and Va) for the following piecing operation of a sliver. Furthermore, the sliver breaking member VII is also returned to a home position for the following piecing operation. It should be noted that the peripheral speed of the sliver feed rollers VIa and VIb may be always equalized to that of the inlet side set of the draft rollers IVa and IVb. Namely, the reduction in the speed of the rollers IVa and IVb causes the speed of the sliver feed rollers VIa and VIb to be reduced. Alternately, the peripheral speed of the sliver feed rollers VIa and VIb may be always the half the speed of the set of the inlet side draft rollers IVa and IVb. Namely, the speed of the feed rollers VIa and VIb is unchanged even if the speed of the inlet side rollers IVa and IVb is reduced during the piecing process. Fig. 2 illustrates, generally, a continuous system having a conveyor system 4 of sliver cans for connecting a drawing frame 1 with a roving frame 2. Namely, slivers produced by the drawing frame 1 are stored in cans, which are delivered to the conveyor 4 in a direction as shown by an arrow a . The roving frame 2 is, at its rear side, along the length thereof, provided with a plurality of rows of cans for slivers being supplied to draft units (not shown) of the roving frame 2. In the embodiment shown in Fig. 2, four rows A, B, C and D of the cans for supplied slivers are provided. In a direction transverse to the length of the roving frame 2, straight columns, each constructed by the cans 5A, 5B, 5C and 5D being supplied, are constructed. The slivers from the cans 5A, 5B, 5C and 5D of the each of the columns are supplied to respective four drafting units (not shown) in the roving frame 2 via a creel not shown in Fig. 2 but shown by a reference numeral 14 in Fig. 4. Connected to the full can supply conveyor 4 is a conveyor 6a arranged between the rows A and B for supplying and exchanging cans for the rows A and B and a conveyor 6b arranged between the rows C and D for supplying and exchanging cans for the rows C and D. Connected to the full can exchanging conveyors 6a and 6b is a conveyor 7 for returning consumed cans replaced by the full cans toward the drawing frame 1 as shown by an arrow b . These conveyors 4, 6a, 6b and 7 are constructed as roller conveyors having a plurality of parallel rolls. It should be noted that a step like consumption of the slivers in the cans is done between the rows A, B, C and D. Namely, the amount of the consumption of the slivers at a selected time is changed under a step like manner between the rows A, B, C and D. Thus, the cans in one of the rows A, B, C and D, which are nearly completely consumed, are replaced by new, full cans 5X. The full cans 5X from the drawing frame 1 are supplied from the conveyor 4 to the full can changing conveyor 6a between the rows A and B for the supplied cans or to the full can changing conveyor 6b between the rows C and D for the supplied cans. A cans exchanger 8 is provided for executing the exchanging operation for replacing the consumed cans in the row A, B, C or D by full cans 5X on the conveyor 6a or 6b. Fig. 2 shows a state where slivers in one of the rows A, B, C and D are nearly fully consumed, and full cans 5X, which are necessary for replacing the all of the cans in the consumed row, are assembled to create a row Xa or Xb of the full cans 5X on the full can exchanging conveyor 6a between the supply can rows A and B or on the full can exchanging conveyor 6b between the supply can rows C and D. As shown in Fig. 2, sets of spaced apart stopper pins 4-1 are provided for the full can exchanging conveyor 6a for the rows A and B of the supplying cans and for the full can exchanging conveyor 6b for the rows C and D, respectively. Solenoid mechanisms (not shown) are provided for the stopper pins 4-1, which are extended to engage the full can at the front end of the row Xa or Xb for obtaining a desired positional relationship of the full can row Xa or Xb with respect to the consumed can row A, B, C or D. Namely, the stoppers 4-1 function to locate the full can row Xa or Xb with respect to the consumed can row A, B, C or D so that the full can row Xa or Xb is offset with respect to the consumed can row A, B, C or D for a length corresponding to one pitch. It should be noted that stoppers 4-1 can be provided in the conveyors 6a and 6b at locations corresponding to each of the feeding cans in the rows A, B, C and D. In Fig. 2, the can exchanger 8 is capable of being moved along the row of cans for the slivers, and executes a progressive replacing operation for replacing, by full cans from the conveyor 6a or 6b, consumed cans on the row A, B, C or D from the one located at the top of the row. Furthermore, a lifter (not shown) is provided for obtaining a desired "rotary" movement of the can exchanger 8 between 180 degree opposite positions, so that a single set of operating mechanisms for executing the can replacing operation, which is provided on only one side of the can exchanger 8, is sufficient for executing a desired can replacing operation wherein the consumed sliver cans on the rows A or B can be replaced by the full cans on the single row Xa, or the consumed sliver cans on the rows C or D can be replaced by the full cans on the single row Xb. Namely, the replacement of the consumed cans on the row A or C is commenced from its left-handed end by moving the exchanger 8 in the right handed direction as will be explained later. In this case, the initial position of the row Xa or Xb of the full cans 5X is determined by the stoppers 4-1, so that the full can row Xa or Xb is offset in the right handed direction for the length of one pitch with respect to the consumed can row A or C. Contrary to this, the replacement of the consumed cans on the row B or D is commenced from its right-handed end by moving the exchanger 8 in the left handed direction. In this case, another set of stoppers (not shown) is provided for determination of the initial position of the row Xa or Xb, so that the full can row Xa or Xb is offset in the left handed direction for the length of one pitch with respect to the consumed can row B or D. Now, an operation for piecing a sliver from a consumed can with a sliver from a full can will be explained. Figs. 3 - (a) and (b) schematically illustrate the sliver feeding operation and the sliver piecing operation. Fig. 3 - (a) illustrates a situation where a feeding unit 70 commences a feeding operation of the sliver S 2 from a full can to a piecing unit 80. Namely, the sliver feed unit 70 is, while the sliver S 2 to be nipped between roller assemblies 702a and 702b, already moved to the position as shown by an arrow i where the sliver feed unit 70 is in a line with respect to the sliver piecing unit 80, so that the set of the rollers 702a and 702b of the sliver feed unit 70 is adjacent with respect to the set of rollers 804 and 844 of the sliver piecing unit. The sliver S 2 issued from the set of the rollers 702a and 702b is, as shown in Fig. 3 - (a), directed to the set of the rollers 804 and 844. It should be noted that, upon the commencement of the feeding operation of the sliver S 2 from the full can, the peripheral speed of the set of the rollers 702a and 702b is controlled so as to be slightly reduced with respect to that of the set of the rollers 804 and 844. As a result, a draft is applied between the set of the rollers 702a and 702b of the feed unit 70 and the set of the rollers 804 and 806 when the brush shaped portion of the broken end of the sliver S 2 is taken by the set of the rollers 804 and 844, so that a rate of the change in the thickness of the end of the sliver S 2 is reduced, when it is combined with the sliver S 1 from a consumed can. Fig. 4 - (a) illustrates a situation that the sliver S2 from the set of the rollers 702a and 702b of the feed unit 70 has, at its brush-shaped end S 2 ', just arrived at the inlet side set of the rollers 804 and 844 of the piecing unit 80. In this situation, the surface speed of the rollers 702a and 702b of the feed unit 70 is slower than that of the rollers 804 and 844 of the piecing unit 80, so that the brush shaped end portion S 2 ' is subjected to drafting, causing its fibers to be displaced with each other. At the timing when the brush shaped end S 2 ' of the sliver S 2 has just completely passed the rollers 804 and 844, the surface speed of the rollers 702a and 702b of the feed unit 70 is equalized to that of the rollers 804 and 844, so that no draft is generated. Fig. 4 - (b) illustrates a situation that the brush-shape portion S 2 ' of the sliver has passed the rollers 804 and 844, which shows that the degree of the change in the thickness of the end of the sliver S2 is reduced as shown by a line P. In Fig. 4 - (b), a dotted line Q shows a shape of the end of the sliver S 2 ' after having passed the rollers 804 and 844, when no draft is applied between the set of the rollers 702a and 702b and the set of the rollers 804 and 844, which corresponds to the brush shaped end of the sliver S 2 , before being introduced into the rollers 804 and 844. Such a slackened shape in the end of the sliver S 2 is advantageous in that a combination with the sliver S 2 can provide a more evenly combined sliver. It should be noted that the draft between the set of the rollers 702a and 702b and the set of the rollers 804 and 844 is obtained only during a very limited period to allow the brushed end portion S 2 ' of the sliver to pass the rollers 804 and 844, and the completion of such a passage of the end portion S 2 ' causes the draft to be instantly canceled, and thereby the peripheral speed of the rollers 702a and 702b and 804 and 844 to be equalized. Again in Fig. 3, the sliver S 1 from the consumed can and the sliver S 2 from the full can, which are combined, are moved into the drafting rollers in the piecing unit 80, the draft ratio of which is now under 1.0. Namely, the thickness of the combined slivers is of the twice thickness of a single sliver. A means such as a timer is provided for detecting a time when the leading end of the sliver S 2 comes to a desired position (for example, intermediate position) between the set of first rollers 804 and 844 and the set of the second rollers 806 and 846. In this instance, a reduction in the speed of the first set of the rollers 804 and 844 is realized by a corresponding reduction of the speed of the motor for rotating the rollers 804 and 844. Simultaneously, a reduction of the speed of the motor for rotating the rollers 702a and 702b is also obtained. As a result, a reduction in the peripheral speed of the first rollers 804 and 844 of the piecing unit 80 and the feed rollers 702a and 702b of the feed unit 70 is realized with respect to the peripheral speed of the second and third sets of rollers 806 and 846, and 808 and 848. As a result, a draft of 2 is applied to the combined slivers S 1 and S 2 between the set of the first rollers 804 and 844 and the second set of the rollers 806 and 846, which causes the thickness of the combined slivers to be reduced to that of a single sliver when the combined slivers come out of the second set of the rollers 806 and 846. Fig. 3 - (b) illustrates schematically how the interwinding of the combined slivers occurs. Namely, when the combined slivers S1 and S 2 are moved in the throttling nozzle 870 between the second set of the rollers 806 and 846 and the third set of the rollers 808 and 848, the converged shape of the nozzle 870 with the throttled outlet end 870-2 causes the combined slivers S 1 and S 2 to be pressed laterally with each other, which causes the fibers to be interwound between the slivers S 1 and S 2 , which causes an integral, single sliver to be come out from the third set of the rollers 808 and 848. Such a throttling of the combined slivers creates, inevitably, a resistance force in the slivers at the nozzle 870, which does not cause the fibers constructing the slivers to be separated, due to the fact that the distance D between the throttle portion 870-2 and the nip point of the rollers 808 and 848 is shorter than an average fiber length D s of the fibers of the slivers. Namely, such a selection of the distance D prevents the fibers from being withdrawn irrespective of the resistance force at the orifice 870, which allows the combined fibers to be taken up by the third set of the rollers 808 and 848. The integrated sliver from the third set of rollers 808 and 848 is, then, passed between the nipping belt 884 and nipping roller 886, which is rotated while reciprocated along the axial direction (the direction transverse to the paper), so that a manual-like rubbing movement is applied to the sliver by the nipping belt 884 and nipping roller 886, which is effective in obtaining an improved interwound condition. Furthermore, the flexibility of the belt 884 allows the nipping roller 886, along its peripheral length, to be engaged with the belt 884, which assists in an increased degree of the engagement of the roller 886 with the belt 884. As a result, an effective rubbing movement in the sliver between the belt 884 and roller 886 is created for obtaining an improved piecing operation. A timer for detecting a desired time after the commencement of the piecing operation issues signals for moving the roller 702b of the feed unit 70 as shown by an arrow h to a position where the roller 702b is spaced from the first roller 702a. As a result, the sliver S 1 from the consumed can is nipped between the back side of the roller 702b and a comb portion 912 of the sliver breaking element 902, which causes the sliver S 1 to be broken. The comb shaped portion 912 provides spaced portions of the sliver nipped between the sliver breaking element 902 and the roller 702b. As a result, a partial separation of the fibers along the width of the sliver occurs between a portion of the sliver near the roller 804 and a portion of the sliver near the can occurs when the sliver S 2 is broken. Thus, an increased length of the portion of reduced number of fibers is obtained at the broken end of the sliver S 1 , which is effective to decrease an unevenness in the combined slivers where this broken end is combined with the sliver S 2 . At a timing where the broken end of the sliver S 1 comes to a desired location (for example, intermediate portion) between the first set of the rollers 804 and 844 and the second set of the rollers 806 and 846, a two times increase in the speed of their motor to the initial value is obtained, which causes the peripheral speed of the first set of the roller 804 and 844 to be equalized to the peripheral speed of the second and third sets of the rollers 806 and 846, and 808 and 848. As a result, the thickness of the combined slivers changes to the thickness of a single sliver, without generating a substantial unevenness. The period for obtaining the draft of 2.0, which is, as explained above, commenced when the sliver S 2 from the full can is come to the desired location between the first set of the rollers 804 and 844 and the second set of the rollers 806 and 846, and is finished when the broken end of the sliver S 1 is come to the desired location between the first set of the rollers 804 and 844 and the second set of the rollers 806 and 846, is a factor to be suitably adjusted so as to obtain the best evenness of the combined slivers.

Claims: A method for piecing a first sliver (S1) fed to a spinning machine to a second sliver (S2) comprising the steps of: nipping the first sliver (S1) by afirst and second set of rollers (804, 844, 806, 846) to feed the first sliver (S1) to the spinning machine; supplying the leading end of the second sliver (S2) to the sets of rollers (804, 844, 806, 846) to combine them while being moved together; interwinding of the fibers of both slivers while being moved; and breaking (902, 912) the first sliver (S1) at the inlet side of the sets of rollers (804, 844, 806, 846) characterized in that the interwinding step comprises the throttling of the combined slivers (S1, S2) at a location following the said sets of rollers (804, 844, 806, 846) to annulary condense the fibers in the combined slivers thereby interwinding the fibers between both slivers, the location having a distance (D) from the nip point of a following third set of rollers (808, 848) which is shorter than the average fiber length (D s ) of the fibers of the slivers. A method according to claim 1, wherein said interwinding comprises a step of rubbing the combined slivers (S1, S2) with each other. A method according to claims 1 or 2, characterized by obtaining different surface speeds between the first and second sets of the rollers (804, 844, 806, 846) so that a draft of about 2.0 is generated in the combined slivers (S1, S2) for reducing the thickness of the combined slivers to that of a single sliver, and; equalizing the surface speeds between the sets of the rollers (804, 844, 806, 846) so that the draft between the opposite sets of the said rollers is reduced to 1.0 after the completion of the piecing operation of the slivers. A method according to claims 1 to 3, characterized by breaking the second sliver at a location adjacent said leading end for creating a desired shape of the broken end of the second sliver. A method according to claims 1 to 4, characterized by breaking the trailing end of the first sliver (S1) on an inlet side of the first set of the rollers (804, 844) so that a separation of the fibers occurs partially along the width of the first sliver, thereby obtaining an increased length of a portion with a reduced number of fibers at the broken end of the first sliver. Apparatus for piecing a first sliver (S1) fed to a spinning machine, to a second sliver (S2) comprising spaced first and second sets of opposite separable rollers (804, 844, 806, 846) to nip the first sliver (S1) between the opposite rollers, means (70) for supplying the second sliver (S2) to the first set of rollers (804, 844) to introduce the leading end of the second sliver (S2) into the sets of rollers, means (870) for interwinding the fibers of the combined slivers, and means (902, 912) for breaking the first sliver on an inlet side of the set of rollers characterized by a throttling nozzle (870) at a location following the said sets of roller (804, 844, 806, 846) through which both combined slivers (S1, S2) are fed to annulary condense the combined slivers, thereby interwinding the fibers between the combined slivers, and that the distance (D) between the throttling nozzle and the nip point of a following third set of rollers (808, 848) is shorter than the average length (D s ) of the fibers of the slivers. An apparatus according to claim 6, characterized by means (808, 884, 886) for rubbing the combined slivers arranged at the outlet side of said third set of the rollers (808, 848). An apparatus according to claim 7, characterized in that the means for rubbing comprises rotating means (886) arranged on the outlet side of the third set of the rollers (808, 848), which member is reciprocally movable in the opposite axial direction while rotating about its own axis, so as to define a nipping plane along the length of supply of the sliver by the rotation of the rollers.

Inventors: KOGISO TAKASHI, KURACHI YOSHIO, KUZUTANI TOSHIYUKI, SEKIYA SHIGEKI, KOGISO, TAKASHI, KURACHI, YOSHIO, KUZUTANI, TOSHIYUKI, SEKIYA, SHIGEKI
Applicants: HOWA MACHINERY LTD, HOWA MACHINERY, LTD.
Application year: 1993
Main classification: D01H15
IPC codes: D01H9, D01H15