Abstract: A method for piecing a yarn at a rotor spinning machine comprising plural spinning stations, wherein more than five piecers are successively produced in a measuring phase and coordinates of measurement values and associated measurement values from individual measurements of the piecers are evaluated for averaging and determining a fiber band function taking into account a drafting reduced for the measurement values, which reflects the fiber flow behavior in the form of the respective fiber band quantity supplied to the rotor as a function of the transport path of the fiber band feed. The speed of the fiber band feed is controlled in a delayed manner from the run-up of the yarn draw-off, dependent on the rotor speed, by the fiber band function, such that the fiber shortfall quantity being produced from the fiber band function is compensated by dynamic feed addition with respect to height and length.

Abstract: A method for operating a spinning machine with plural spinning stations (1), each case having a take-off roller device (6, 10, 14) for drawing a yarn (9) from a spinning device (2) and a sensor mechanism (26) for checking piecings. When starting a piecing, the theoretical conveying length of the yarn is determined based on the surface speed of the rollers (10, 14), until the piecing reaches the sensor mechanism (26). The deviation of the theoretical conveying length from a desired yarn length, corresponding to the spacing between the spinning device (2) and the sensor mechanism (26), is detected. The deviation is compared with a preadjustable limit value of the permissible deviation. If the limit value is passed, this indicates intolerable wear of the pressure roller (14) and produces a signal.

Abstract: A method for piecing a yarn at a rotor spinning machine comprising plural spinning stations, wherein more than five piecers are successively produced in a measuring phase and coordinates of measurement values and associated measurement values from individual measurements of the piecers are evaluated for averaging and determining a fiber band function taking into account a drafting reduced for the measurement values, which reflects the fiber flow behaviour in the form of the respective fiber band quantity supplied to the rotor as a function of the transport path of the fiber band feed. The speed of the fiber band feed is controlled in a delayed manner from the run-up of the yarn draw-off, dependent on the rotor speed, by the fiber band function, such that the fiber shortfall quantity being produced from the fiber band function is compensated by dynamic feed addition with respect to height and length.

Abstract: The invention relates to a method for operating an open-end spinning device (1), comprising a spinning rotor (2) and an opening roller (12), which can be controlled so as to be driven individually independently of one another, wherein after an interruption in the spinning process takes place as a result of the detection of the absence of a thread, a piecing operation is initiated, comprising a piecing process, in which an upper thread passes through a fiber ring formed in the spinning rotor (2) and is connected to the latter, and a subsequent drawing-in accumulating process which serves to reduce a thin point in the thread following the piecer, wherein during the piercing operation, the opening roller (12) is temporarily driven at a piecing speed which is higher than the operating speed of the opening roller (12).

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: The invention relates to a method for operating an open-end spinning device (1), comprising a spinning rotor (2) and an opening roller (12), which can be controlled so as to be driven individually independently of one another, wherein after an interruption in the spinning process takes place as a result of the detection of the absence of a thread, a piecing operation is initiated, comprising a piecing process, in which an upper thread passes through a fiber ring formed in the spinning rotor (2) and is connected to the latter, and a subsequent drawing-in accumulating process which serves to reduce a thin point in the thread following the piecer, wherein during the piercing operation, the opening roller (12) is temporarily driven at a piecing speed which is higher than the operating speed of the opening roller (12).

Abstract: A method for operating a spinning machine with plural spinning stations (1), each case having a take-off roller device (6, 10, 14) for drawing a yarn (9) from a spinning device (2) and a sensor mechanism (26) for checking piecings. When starting a piecing, the theoretical conveying length of the yarn is determined based on the surface speed of the rollers (10, 14), until the piecing reaches the sensor mechanism (26). The deviation of the theoretical conveying length from a desired yarn length, corresponding to the spacing between the spinning device (2) and the sensor mechanism (26), is detected. The deviation is compared with a preadjustable limit value of the permissible deviation. If the limit value is passed, this indicates intolerable wear of the pressure roller (14) and produces a signal.

Abstract: It is the object of the invention to propose a method for open-end rotor spinning, wherein the formation of cover yarn, in particular the so-called “belly bands”, is at least appreciably reduced. In accordance with the invention, the fiber flow exiting a fiber guide channel has a directional component in the direction of rotation of the rotor, while the yarn leg (3) extending, from the draw-off nozzle to the rotor groove, is curved opposite the direction of rotation of the rotor, at least near the rotor groove (1), during the spinning process. The creation of this direction of curvature of the yarn leg (3) takes place during the piecing process.

Abstract: It is the object of the invention to propose a method for open-end rotor spinning, wherein the formation of cover yarn, in particular the so-called “belly bands”, is at least appreciably reduced.

Abstract: A method for producing graduated precision windings on cheeses in an open-end spinning system. The winding ratio is reduced in stages, in increasingly smaller graduations, as the cheese diameter increases during the bobbin travel of the cheese. The graduations do not exceed the value of 0.3 and are each selected such that changes in the crossing angle are within a tolerance range of less than ±0.8°, and the least number of diamonds occurring during the building of the bobbin can be completely filled. The cheeses thusly produced are distinguished by a stable construction, high density with uniform distribution of density over the entire yarn package, and excellent payout properties.

Abstract: A method for producing a cheese, wherein the cheese rotates around its longitudinal axis and the yarn is subjected to a cross-winding movement while being fed to the cheese and wound thereon, and having a crossing angle, a winding angle and a placement distance associated therewith. The method including the steps of controlling the crossing angle and the winding ratio as a function of the cheese diameter during the winding process while controlling the placement distance so that it increases in conjunction with an increasing cheese diameter thereby preventing deformations and improving the production of cheeses. A cheese produced in accordance with the method of the present invention offers advantages for stacking and during transport.

Abstract: A traversing yarn guide (5) that is moved back and forth produces cross winding of yarn on a bobbin at each winding head of a textile spinning or winding machine in order to wind cross-wound bobbins. After a yarn interruption, an auxiliary yarn guide (4) in an active position keeps the yarn in a position that is raised out of the traversing yarn guide (5). In a rest position (40′), the auxiliary yarn guide (4) does not influence the yarn and the traversing yarn guide (5) can grasp and take the yarn to be wound from the auxiliary yarn guide (4).

Abstract: A method for producing graduated precision windings on cheeses in an open-end spinning system. The winding ratio is reduced in stages, in increasingly smaller graduations, as the cheese diameter increases during the bobbin travel of the cheese. The graduations do not exceed the value of 0.3 and are each selected such that changes in the crossing angle are within a tolerance range of less than ±O.8°, and the least number of diamonds occurring during the building of the bobbin can be completely filled. The cheeses thusly produced are distinguished by a stable construction, high density with uniform distribution of density over the entire yarn package, and excellent payout properties.

Abstract: A piecing device with an evaluation arrangement for determining parameters of an automatic piecing process at a spinning station (1) of an open-end spinning frame, wherein a control device is provided which, initially in a test phase, controls the creation of at least one test piecing without a supplementary delivery of additional fiber and the subsequent removal of the created test piecing. The evaluation device is designed for determining the length of a thinner extent of the test piecing downstream of the test piecing as viewed in the direction of yarn travel, and for the determination from the detected length of the thinner extent an amount of supplementary delivery of additional fiber required for compensating the thinner extent. A reduction of the draft which is effective during the test phase assures an interference-free checking of the test piecing. The optimization phase for piecings is shortened and leads to a more accurate result when determining the supplementary delivery of additional fiber.

Abstract: A method for producing a cheese, wherein the cheese rotates around its longitudinal axis and the yarn is subjected to a cross-winding movement while being fed to the cheese and wound thereon, and having a crossing angle, a winding angle and a placement distance associated therewith. The method including the steps of controlling the crossing angle and the winding ratio as a function of the cheese diameter during the winding process while controlling the placement distance so that it increases in conjunction with an increasing cheese diameter thereby preventing deformations and improving the production of cheeses. A cheese produced in accordance with the method of the present invention offers advantages for stacking and during transport.

Abstract: A traversing yarn guide (5) that is moved back and forth produces cross winding of yarn on a bobbin at each winding head of a textile spinning or winding machine in order to wind cross-wound bobbins. After a yarn interruption, an auxiliary yarn guide (4) in an active position keeps the yarn in a position that is raised out of the traversing yarn guide (5). In a rest position (4′), the auxiliary yarn guide (4) does not influence the yarn and the traversing yarn guide (5) can grasp and take the yarn to be wound from the auxiliary yarn guide (4).

Abstract: In a method and apparatus for determining a variation in criteria, parameters and/or command values of an automatic piecing operation at an automatic piecing apparatus of an automatic spinner, a piecer and/or a length of thread in which the piecer is located is measured in accordance with criteria of diameter or diameter per unit of length and evaluated for improving the piecer, with at least one sensor disposed in a thread travel path, upon resumption of winding after a piecing operation in which a spun yarn is received. A piece of thread containing the piecer is scanned by measuring with the at least one sensor in terms of location of thick and/or thin places with respect to the piecer at defined measurement points, as further criteria of the piecing operation. The measured data are continuously input into event counters connected downstream of the at least one sensor.

Abstract: A method includes dividing a yarn into various sections with reference to the pieced yarn section, with each section being characteristic of the piecing process. A yarn profile in each section is measured and evaluated against criteria specific to each section, whereby a yarn defect and its position on the yarn are determined and from which the cause for the defect is determined. The pieced yarn section is also divided into three subsections and each subsection is measured and evaluated against certain subsection criteria for the detection of fluff, trash accumulation and fiber sloughing.

Abstract: A rotor spinning machine has a plurality of simultaneously operated spinning stations each with a spinning rotor, an opening roller, a feed roller for delivering sliver to the opening roller, and a stepping motor connect directly to the feed roller for driving thereof. An actuating arrangement is provided for selectively actuating each stepping motor in a normal increment mode during spinning operation and in a microincrement mode during yarn piecing operations.

Abstract: In a rotor spinning machine, each spinning station's drawing-in roller is connected directly to its own individual drive supported by the cover of the spinning station housing, which provides a simplified and conveniently accessible alternative to the conventional worm gear driving of the drawing-in rollers of the machine's plural spinning stations from a common drive shaft.