Abstract: A method for operating an open-end rotor spinning machine having a plurality of workstations, usually a large number, each including a spinning device with a rotor housing, to which negative pressure can be applied, in which a spinning rotor (23) revolves at a high rotational speed, to produce a yarn, as well as a winding device to produce a cross-wound bobbin (18), wherein the connection of the workstations to a central negative pressure supply can be selectively switched off. The application of negative pressure to the rotor housing is limited to the spinning devices which are producing yarn as well as the spinning devices which are repiecing.

Abstract: A method for operating an open-end rotor spinning machine having a plurality of workstations, usually a large number, each including a spinning device with a rotor housing, to which negative pressure can be applied, in which a spinning rotor (23) revolves at a high rotational speed, to produce a yarn, as well as a winding device to produce a cross-wound bobbin (18), wherein the connection of the workstations to a central negative pressure supply can be selectively switched off. The application of negative pressure to the rotor housing is limited to the spinning devices which are producing yarn as well as the spinning devices which are repiecing.

Abstract: Yarn draw-off device for a textile machine producing cross-wound bobbins with a yarn draw-off roller that can be driven by a single motor and an associated pressure roller which is driven via frictional engagement, characterised in that the yarn draw-off roller (10) has a rotationally symmetrical basic member (15) with devices (33), which, during the rotation of the yarn draw-off roller (10) produce an air flow which cools the yarn draw-off roller drive (13).

Abstract: A suction air nozzle for a textile machine for storing a yarn length of a running yarn passing the nozzle opening. The nozzle has an elongate nozzle body, with a clear cross section having a narrower width in the region of its central longitudinal axis than in its tube-like edge regions. The nozzle further has an inlet opening, which has its largest width in the yarn running direction. The clear cross section of the nozzle body of the suction air nozzle increases from the inlet opening of the nozzle body in the axial direction to an end-side outlet opening.

Abstract: A method for avoiding ribbon windings in producing cross-wound bobbins at the workstations of textile machines in the “random winding” type of winding, by changing the traversing speed at which the thread is wound onto the bobbin. Each workstation has a single motor drive activated for the rotation of the cross-wound bobbin, and a single motor drive activated for a traversing thread guide. The diameters (DSP k) of the bobbin (8) which are critical with regarding to the development of ribbon windings depending on the width (BSp) of the bobbin (8) and a cross-winding angle (?) are determined, and, shortly before reaching each critical diameter (DSP k), the cross-winding angle (?) is changed to a value (?1), which avoids development of ribbon windings in this diameter region, and the cross-winding angle (?1) is reset to its original value (?) after the critical diameter (DSP k) has been passed.

Abstract: A suction air nozzle for a textile machine for storing a yarn length of a running yarn passing the nozzle opening. The nozzle has an elongate nozzle body, with a clear cross section having a narrower width in the region of its central longitudinal axis than in its tube-like edge regions. The nozzle further has an inlet opening, which has its largest width in the yarn running direction. The clear cross section of the nozzle body of the suction air nozzle increases from the inlet opening of the nozzle body in the axial direction to an end-side outlet opening.

Abstract: A creel loading and relieving device for a winding device of a textile machine producing crosswound bobbins adjusts the contact pressure of a take-up bobbin mounted in a creel on a driving roll. The creel loading and relieving device comprises a creel pivotally mounted via a creel shaft and a force applying means which grips the creel and is adjustable via a positioning element. The creel loading and relieving device (30) has an actuator (33) that can be positioned by an electromotive drive (40) while a force applying means (29) which impinges upon the creel (9) is disposed on said actuator (33). The force applying means is configured as a pneumatic spring (29) and is hinged to a first lever arm (25) connected to a creel yoke (24). The loading or relieving moment applied to the creel (9) by the pneumatic spring (29) can be adjusted with precision by positioning the actuator (33).

Abstract: A method and device for producing cross-wound textile bobbins using a creel for holding a cross-wound bobbin, a bobbin drive roller operated by a single drive to rotate the bobbin and a thread traversing mechanism driven by a single motor. At a predetermined bobbin diameter or a predetermined thread length, a thread guide of the traversing mechanism is positioned to adjust a thread end reserve for an adjustable time span. While the thread end reserve (10) is being produced, a thread storage suction nozzle (60) particular to the winding head acts on the thread (7) running onto the bobbin (8) to intermediately store excess thread length being produced during the winding of the thread end reserve (10) and to insure a minimum thread tension to reliably fix the thread end reserve (10) on the bobbin body or the cross-wound bobbin tube.

Abstract: A system for determining a zero position of a yarn guide (25) of a textile winding device for cross-winding yarn into cheeses via a step motor (34). The yarn guide (25), acted upon by the step motor (34), is initially displaced in the direction of its zero position (NS) and positioned at a slow speed against a defined detent (15) downstream of the zero position (NS). Then, the step motor (34) is switched off, causing the rotor (41) of the step motor (34) to drop into one of two possible stop positions (RS1, RS2). Subsequently, the step motor (34) is switched on by an electrical current supply to its stator windings (20A, 20B) such that, when switched off, the rotor (41) of the step motor (34) is in the stop position (RS2) in which the yarn guide (25) is in its zero position (NS).

Abstract: A drive roller on a textile machine producing cross-wound bobbins, for the frictional drive of a cross-wound bobbin, mounted to rotate in a spool frame on a spooling device, wherein the outer circumference (21) of the drive roller (11) is embodied by a thin-walled, profiled metal tube (19), formed by high-pressure internal forming.

Abstract: This invention relates to a thread traversing device for a winding device of a cross-wound bobbin producing textile machine. Said thread traversing device has a thread guide which is guided in a thread guide rod in the working area and is connected to an individual drive mechanism by a continuous traction mechanism. According to the invention, the thread traversing device (11) has a substantially closed housing (23,) whose inner space (37) in the traversing area (B) of the thread guide (25) is sealed by the continuous traction mechanism (30).

Abstract: A system for determining a zero position of a yarn guide (25) of a textile winding device for cross-winding yarn into cheeses via a step motor (34). The yarn guide (25), acted upon by the step motor (34), is initially displaced in the direction of its zero position (NS) and positioned at a slow speed against a defined detent (15) downstream of the zero position (NS). Then, the step motor (34) is switched off, causing the rotor (41) of the step motor (34) to drop into one of two possible stop positions (RS1, RS2). Subsequently, the step motor (34) is switched on by an electrical current supply to its stator windings (20A, 20B) such that, when switched off, the rotor (41) of the step motor (34) is in the stop position (RS2) in which the yarn guide (25) is in its zero position (NS).

Abstract: In an open-end spinning machine (1) with a plurality of open-end spinning devices (3), each having a spinning rotor (15) whose rotor shaft (26) is seated in the bearing wedge of an axial thrust-free support disk bearing (27) and is positioned by a magnetic bearing (29), and a service unit (10), which automatically services the spinning devices, a sensor device (41) is provided on the service unit (10), which is connected to the control device (18) of the service unit (10) and checks an identification marker (34) applied to each spinning rotor (15). The control device (18) actuates a yarn piecing operation by the service unit only upon detection of an identification marker (34) identifying the spinning rotor (15) to be compatible with the associated spinning device.

Abstract: In the course of the installation or removal of an opening roller, the opening fittings, which for example consist of many pointed needles or a sawblade-shaped metal strip, represent a considerable risk of injury. So far no devices are known in connection with opening rollers driven by individual motors which, make unintended starting of the rollers impossible while being replaced and serviced. In accordance with the invention, an opening device has a locking and unlocking device which assures an orderly operation of the opening roller driven by an individual motor and also assures that while servicing or installing the opening roller no danger of injuries can occur, for example because of an unintended starting of the opening roller.

Abstract: A magnetic bearing is disclosed for an open-end spinning rotor having a shaft supported in a wedge-like gap formed between at least one pair of support rollers. The bearing comprises a housing for receiving the shaft, a magnet disposed in the housing to extend radially relative to the shaft, and a magnet disposed on and radially extending from the shaft axially adjacent and at a spacing from the magnet in the bearing housing. The magnets have respective poles of the same magnetic orientation disposed to face and thereby repel one another. According to the invention, a coupling connects the shaft and the magnet disposed on the shaft, the coupling being releasable in response to an axial force exerted on the shaft.

Abstract: A method for forming a yarn reserve on an end surface of a cross-wound bobbin or cheese disposed on a bobbin tube includes predetermining a length of yarn for a yarn reserve. The yarn is unwound to the predetermined length from a cheese while temporarily storing the yarn in a reservoir. The presence of the yarn in the reservoir is detected with a sensor. The unwinding of the yarn is stopped and the rotational direction of the cheese is reversed to the given winding direction after attaining the predetermined length of the yarn. The yarn is then wound onto the one end of the bobbin tube while continuously holding the yarn taut with a restraining force of the reservoir. An apparatus for changing cheeses on a machine that produces cheeses and for forming a yarn reserve on an end surface of a cheese disposed on a bobbin tube includes a drive mechanism for unwinding a predetermined length of a yarn from a cheese. A reservoir receives and stores the yarn from the cheese.

Abstract: A method for transferring a yarn after a yarn break to a normal yarn travel position at a textile machine winding station including making a yarn connection between a yarn supply point and a takeup bobbin and subsequently transferring the yarn to the normal yarn travel position at a transfer point at the reciprocating yarn guide with a tranfer motion of a yarn transfer device of a device that re-establishes yarn travel. The chronological course of the making of the yarn connection and the transverse motion of the yarn guide are monitored. The tranfer motion of the yarn transfer device and the transverse motion of the yarn guide are adapted to one another as a function of the chronological course for causing the yarn and the yarn guide to substantially simultaneously arriving at the transfer point. An apparatus for performing the method includes a first device for monitoring reciprocation of the yarn guide to a yarn tranfer point.