Method of and apparatus for detecting faults in the operation of open-end spinning machines

A method of detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, which method comprises the steps of

• measuring the cross-section or diameter of yarn leaving at least one spinning unit,
• converting the measurement into an electrical signal, and
• processing said electrical signal in a discriminator to detect irregularities in said measurement by
• applying a non-linear correcting characteristic to said signal by a correcting means,
• integrating the corrected signal in an integrator, and
• comparing the integrated signal with a predetermined reference signal in a comparator,
• thereby generating a control signal upon the occurrence of said irregularities,
• wherein periodically recurring changes in yarn cross-section are detected by frequency-selective filters as irregularities in said electrical signal, and
• wherein said electrical signal having said irregularities is applied to the input of the correcting means by parallel connection of high-pass and low-pass frequency-selective filters to said correcting means to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween.

An apparatus for detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, said apparatus comprising

• measuring means for generating an electrical signal representative of the cross-sectional diameter of yarn passing from at least one spinning unit, and
• discrimator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities being representative of excessive variations in said cross-sectional diameter,
• wherein said discriminator means includes
• at least one correcting circuit means with a non-linear characteristic for applying said non-linear characteristic to said electrical signal,
• an integrator circuit means connected to said correcting circuit means for integrating the corrected signal, and
• a comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal,
• wherein said discriminator means further includes
• at least one frequency-selective filter means for determining frequency components of said electrical signal, and
• wherein said frequency-selective filter means include high-pass and low-pass frequency-selective filters connected in parallel to said correcting circuit means to select only frequencies above the cut-off of said high-pass filter and below the cut-off of said low-pass filter, and suppress all frequencies therebetween.

An arrangement for detecting the defective operation of spinning units in open-end spinning machines, especially disturbances attributable to fouling of the spinning units, said apparatus comprising

• measuring means for generating an electrical signal representative of the cross-sectional diameter of yarn passing from at least one spinning unit, and
• discriminator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities of excessive variations in said cross-sectional diameter,
• wherein sid discriminator means includes
• at least one correcting circuit means with a non-linear characteristic for applying said non-linear characteristic to said electrical signal,
• an integrator circuit means connected to said correcting circuit means for integrating the corrected signal, and
• a comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal, and
• wherein said predetermined reference signal is provided by the outputs of at least two of said integrator circuit means connected in parallel.

A method of detecting the defective operation of spinning units in open-end spinning machines comprising the steps of

• measuring the cross-section or diameter of yarn leaving at least one spinning unit,
• converting the measurement into an electrical signal, and
• processing said electrical signal in a discriminator to detect irregularities in said measurement by
• applying a non-linear characteristic to said electrical signal with a correcting device receiving said electrical signal to provide a corrected signal which emphasizes larger deviations of said cross-section or diameter of said yarn over smaller deviations thereof,
• integrating said corrected signal in an integrator connected to said correcting device to determine the frequency of occurrence of said larger deviations of said yarn, and
• comparing the integrated signal with a predetermined reference signal in a comparator connected to said integrator,
• thereby generating a control signal upon the occurrence of predetermined deviations of said cross-section or diamter of said yarn.

An apparatus for detecting the defective operation of spinning units in open-end spinning machines comprising

• measuring means for generating an electrical signal representative of the cross-section or diameter of yarn passing from at least one spinning unit, and
• discriminator means connected to said measuring means for generating a control signal in response to irregularities in said electrical signal, said irregularities being representative of excessive deviations in said cross-section or diameter of said yarn, and said discriminator means including
• at least one correcting circuit means receiving said electrical signal for applying a non-linear characteristic to said electrical signal to provide a corrected signal which emphasizes larger deviations of said cross-section or diameter of said yarn over smaller deviations thereof,
• integrator circuit means connected to said correcting circuit means for integrating the corrected signal to determine the frequency of occurrence of said larger deviations of said yarn, and
• comparison circuit means connected to said integrator circuit means for comparing the integrated signal with a predetermined reference signal to generate said control signal upon the occurrence of predetermined deviations of said cross-section or diameter of said yarn.