Abstract: A yarn-winding assembly mounted on a support is provided with a motorized spool and with an oblique spacing pin, between which a yarn is wound. The spacing pin is supported so that it can rotate about an axis of the motorized spool by unidirectional rotary support elements. The spacing pin rotates freely with respect to the spool when the latter rotates in the yarn unwinding direction and the former is retained from rotating by stop elements, and is instead integral with the spool when the spool rotates in the opposite yarn rewinding direction.

Abstract: A yarn-winding assembly mounted on a support is provided with a motorized spool and with an oblique spacing pin, between which a yarn is wound. The spacing pin is supported so that it can rotate about an axis of the motorized spool by unidirectional rotary support elements. The spacing pin rotates freely with respect to the spool when the latter rotates in the yarn unwinding direction and the former is retained from rotating by stop elements, and is instead integral with the spool when the spool rotates in the opposite yarn rewinding direction.

Abstract: A drum has a plurality of yarn loops wound thereon which are to be unwound upon request from a downstream machine. A weft-braking device provided with a braking member having a circular profile is biased against a delivery edge of the drum by driving elements. The yarn is adapted to run between the delivery edge and the braking member to receive a braking action by friction from them. The driving elements comprise at least one piezoelectric actuator which is deformable in response to a voltage applied thereto and has a movable operative end which is operatively connected to the braking member and a stationary operative end which is anchored to a stationary support.

Abstract: The weft-braking device comprises a first annular plate coaxially supported in front of the delivery end of a stationary drum of a yarn feeder, and a second annular plate which is coaxially biased against the first annular plate by driving elements. The yarn is adapted to run between the annular plates in order to receive a braking action by friction. The driving elements comprise at least one piezoelectric actuator, which is deformable in response to a voltage applied thereto and has a movable operative end which is operatively connected to the second annular plate and a stationary operative end which is anchored to a stationary support.

Abstract: A motorized yarn-winding drum holds a plurality of loops of yarn wound thereon and is driven to rotate for drawing said yarn from a reel and feeding it to a general downstream machine. A movable guiding member is biased to slideably engage the yarn unwinding from the drum and to deviate its path, by a spring acting in contrast to the tension of the yarn, thereby generating a reserve releasable in response to tension peaks on the yarn. The stroke of the guiding member is limited by a stop defining a position of maximum deviation of the yarn. The spring has one end operatively connected to the guiding member and one opposite end connected to driving elements operable for applying a load to the spring, with the guiding member abutting against said stop. The driving elements are controlled by a control unit which is programmed to adjust the load as a function of a desired feeding tension.

Abstract: In order to detect the stop of the yarn unwinding from a yarn feeder provided with a stationary drum and with a sensor generating a pulse per each yarn loop unwound from the drum, a threshold time interval is continuously computed, which corresponds to the maximum interval between two successive pulses, above which it should be regarded that an accidental stop of the yarn has occurred. The threshold time interval is updated in real time as a function of the yarn-drawing speed. Then the delay from the last pulse is continuously measured and compared with the updated threshold time interval. The machine is stopped when the measured delay overcomes the updated threshold interval.

Abstract: A motorized yarn-winding drum holds a plurality of loops of yarn wound thereon and is driven to rotate for drawing said yarn from a reel and feeding it to a general downstream machine. A movable guiding member is biased to slideably engage the yarn unwinding from the drum and to deviate its path, by a spring acting in contrast to the tension of the yarn, thereby generating a reserve releasable in response to tension peaks on the yarn. The stroke of the guiding member is limited by a stop defining a position of maximum deviation of the yarn. The spring has one end operatively connected to the guiding member and one opposite end connected to driving elements operable for applying a load to the spring, with the guiding member abutting against said stop. The driving elements are controlled by a control unit which is programmed to adjust the load as a function of a desired feeding tension.

Abstract: A knitting line comprises a plurality of yarn feeders from which a downstream machine draws respective yarns. The machine is provided with selection elements adapted to vary the state of selection of the yarn feeders in relation to the angular position of the machine. Each of the yarn feeders is provided with a stationary drum and with a yarn count sensor arranged to generate a pulse per each yarn loop unwound from the drum. A selection signal is periodically sent to the yarn feeders, which is indicative of the state of selection of the individual feeders in relation to the angular position of the machine.

Abstract: A knitting line comprises a plurality of yarn feeders from which a downstream machine draws respective yarns. The machine is provided with selection elements adapted to vary the state of selection of the yarn feeders in relation to the angular position of the machine. Each of the yarn feeders is provided with a stationary drum and with a yarn count sensor arranged to generate a pulse per each yarn loop unwound from the drum. A selection signal is periodically sent to the yarn feeders, which is indicative of the state of selection of the individual feeders in relation to the angular position of the machine.

Abstract: The tension is modulated by a weft-braking device controlled by a tension control block programmed for comparing the measured tension with a reference tension, and for transmitting a braking level signal to the weft-braking device, which braking level signal is adapted to minimize the difference between the measured tension and the reference tension. The yarn consumption speed is calculated, then the yarn consumption speed is compared with a predetermined threshold speed, and if the calculated consumption speed overcomes the predetermined threshold value, the tension control block is enabled, while, if the calculated consumption speed is lower than the threshold value, the tension control block is disabled and the last signal generated by the latter is maintained as braking signal, until the yarn consumption speed overcomes again the threshold value.

Abstract: In order to detect the stop of the yarn unwinding from a yarn feeder provided with a stationary drum and with a sensor generating a pulse per each yarn loop unwound from the drum, a threshold time interval is continuously computed, which corresponds to the maximum interval between two successive pulses, above which it should be regarded that an accidental stop of the yarn has occurred. The threshold time interval is updated in real time as a function of the yarn-drawing speed. Then the delay from the last pulse is continuously measured and compared with the updated threshold time interval. The machine is stopped when the measured delay overcomes the updated threshold interval.

Abstract: A motorized yarn-winding drum holds a plurality of loops of yarn wound thereon and is driven to rotate for drawing said yarn from a reel and feeding it to a general downstream machine. A movable guiding member is biased to slideably engage the yarn unwinding from the drum and to deviate its path, by a spring acting in contrast to the tension of the yarn, thereby generating a reserve releasable in response to tension peaks on the yarn. The stroke of the guiding member is limited by a stop defining a position of maximum deviation of the yarn. The spring has one end operatively connected to the guiding member and one opposite end connected to driving elements operable for applying a load to the spring, with the guiding member abutting against said stop. The driving elements are controlled by a control unit which is programmed to adjust the load as a function of a desired feeding tension.

Abstract: Yarn loops are unwound from a stationary weft-winding drum during a weft insertion. A weft-braking device locks the yarn unwinding from the drum at the end of the insertion, and comprises at least one braking member which is arranged by side of the drum near its delivery end and is movable under control of an actuator between a resting position in which it is spaced from the outer surface of the drum and does not interfere with the unwinding yarn, and an operative position in which it engages the outer surface of the drum and cooperates with it to brake the yarn.

Abstract: The tension is modulated by a weft-braking device controlled by a tension control block programmed for comparing the measured tension with a reference tension, and for transmitting a braking level signal to the weft-braking device, which braking level signal is adapted to minimize the difference between the measured tension and the reference tension. The yarn consumption speed is calculated, then the yarn consumption speed is compared with a predetermined threshold speed, and if the calculated consumption speed overcomes the predetermined threshold value, the tension control block is enabled, while, if the calculated consumption speed is lower than the threshold value, the tension control block is disabled and the last signal generated by the latter is maintained as braking signal, until the yarn consumption speed overcomes again the threshold value.

Abstract: The three-way connector comprises a first, a second and a third gates directly connected to one another. The first and second gate are pluggable onto respective spans of a bus, and the third gate is connectable to a weft feeder. The three-way connector further comprises a permanent memory containing an identifying code for the associated weft feeder. A managing unit drives a serial bus to which a plurality of weft feeders are connected. The serial bus comprises the cable spans, serially connected to one another through the first and second gates of the connectors, the weft feeders being connected to respective third gates of the connectors.

Abstract: The three-way connector comprises a first, a second and a third gates directly connected to one another. The first and second gate are pluggable onto respective spans of a bus, and the third gate is connectable to a weft feeder. The three-way connector further comprises a permanent memory containing an identifying code for the associated weft feeder. A managing unit drives a serial bus to which a plurality of weft feeders are connected. The serial bus comprises the cable spans, serially connected to one another through the first and second gates of the connectors, the weft feeders being connected to respective third gates of the connectors.

Abstract: A self-adjusting braking device for weft feeders, comprising a frustum-shaped braking body that acts on a thread, is suspended elastically in front of the drum of the feeder and is pushed into elastic tangent contact with the drum along an exit circumference of the drum. The braking body has, at a larger-diameter region thereof designed to make contact with the drum, a discontinuous annular contact element, with a plurality of through slits which are arranged so as to be equidistant and delimit a row of contact laminas.

Abstract: A device for smoothening the unwinding from the cylinder of the loops of yarn of the weft reserve in weft suppliers for fluid jet looms, is described. The device comprises a pneumatic device capable of subjecting the yarn to a fluid flow, such as an air stream, having at least one motion component directed in the running direction of the yarn. The flow, independently from the dimensional and superficial characteristics of the yarn, maintains the latter constantly under mechanical tension, so that the slackening of the loops wound on the terminal portion of the cylinder of the supplier is prevented.

Abstract: A device for smoothening the unwinding from the cylinder of the loops of yarn of the weft reserve in weft suppliers for fluid jet looms, is described. The device comprises a pneumatic device capable of subjecting the yarn to a fluid flow, such as an air stream, having at least one motion component directed in the running direction of the yarn. The flow, independently from the dimensional and superficial characteristics of the yarn, maintains the latter constantly under mechanical tension, so that the slackening of the loops wound on the terminal portion of the cylinder of the supplier is prevented.

Abstract: A self-adjusting braking device for weft feeders, comprising a frustum-shaped braking body that acts on a thread, is suspended elastically in front of the drum of the feeder and is pushed into elastic tangent contact with the drum along an exit circumference of the drum. The braking body has, at a larger-diameter region thereof designed to make contact with the drum, a discontinuous annular contact element, with a plurality of through slits which are arranged so as to be equidistant and delimit a row of contact laminas.