Abstract: A yarn piecing method in an open-end spinning machine comprises stopping a yarn piecing machine in front of a spinning unit suffering a yarn breakage, reversing a package with a rewinding roller to rewind a yarn therefrom, cutting off the yarn to provide a yarn end having a predetermined length, moving the yarn end to a position upwardly of an outlet of a withdrawal tube in the spinning unit, reversing the rewinding roller again to feed the yarn end through the withdrawal tube to a fiber collecting surface of a spinning rotor in the spinning unit, supplying a sliver with a feed roller into the spinning unit, piecing the yarn end to the sliver on the fiber collecting surface, continuously drawing a pieced yarn from the spinning rotor, and moving the pieced yarn to a position between a presser roller and a draw-off roller which are being rotated while drawing the pieced yarn from the spinning rotor.

Abstract: A method for yarn piecing in a fasciated yarn spinning unit, in which an air nozzle for twisting a fiber bundle to form a fasciated yarn is displaced from the normal spinning position to the threading position where the air nozzle can escape from the front roller pair, whereby a free space is prepared for applying a suction means having a sufficient suction force to reversely thread a yarn to be pieced through the air nozzle.

Abstract: Method and apparatus for yarn piecing in a ringless spinning machine is provided, according to which yarn piecing is accomplished by unwinding a yarn from its package, rewinding a portion of the unwound yarn on to the package at one, definite position, cutting off the yarn end to a predetermined length, then introducing the cut end of the yarn into the spinning mechanism of the spinning unit, and then withdrawing the yarn from the spinning unit after the yarn end is connected with the fibers in the spinning mechanism.

Abstract: Yarns are pieced in a spinning machine utilizing an air stream, such as an open-end spinning machine or an air-jet spinning machine. For yarn piecing, an end of a yarn unwound from a bobbin is inserted into a twisting mechanism, and a sliver is newly supplied as a fleece so as to intertwine with the yarn end forming a pieced yarn portion. The thickness of the unwound yarn is detected by a detector and stored in a memory prior to insertion into the twisting mechanism. After the yarn and the sliver have been joined, the thickness of the pieced yarn portion is detected by the detector, and the detected thickness is compared with the stored thickness of the unwound yarn. If the thickness of the pieced yarn portion exceeds an allowable value as a result of such comparison, then the yarn is severed by a cutter, and thereafter a cut end of the yarn is pieced again with the fleece.

Abstract: Sliver weight unevenness correcting apparatus of a feed-forward type has: a sliver weight measuring section for detecting the variations in weight of a bundle of slivers; a correcting draft device having front rollers disposed downstream of the sliver weight measuring section relative to the direction of advancement of slivers, the front rollers being rotated at a constant speed, and back rollers disposed between the sliver weight measuring section and the front rollers, the back rollers being rotated at a variable speed; a rotation detector for detecting the number of revolutions of the front rollers; an unevenness correcting circuit having a ratio circuit for operating a ratio (E.sub.0 /E.sub.1) between a reference sliver weight (E.sub.0) and the detected weight (E.sub.1) thereof, a delay circuit for delaying the speed control of the back rollers of the correcting draft device for a predetermined period of time, and a contrasting operational circuit for multiplying the ratio (E.sub.0 /E.sub.

Abstract: A method and apparatus for controlling the sliver thickness variation in a carding machine. The thickness variation of the sliver delivered from the carding machine is measured and an electrical signal corresponding to the thickness variation of the carded sliver is issued. A difference signal is created by comparing the above-mentioned electric signal, and a control pulse signal in accordance with the difference signal is intermittently created at predetermined time intervals, each of said time intervals being shorter than a time required for a length of the carded sliver which length corresponds to a long term variation of the carded slivers thickness. The supply amount of fiber tufts to the carding machine is intermittently adjusted for reducing the above-mentioned control signal toward zero by said control pulse signal at each of said time intervals.