Thread-guide device for the production of bobbins with traversing modulation

Abstract

Thread-guide device with modulated traversing with an individual thread-guide with a back-and-forth movement fixed to a cord open at the two ends and moved between two pulleys in an alternating clockwise/anticlockwise movement, each activated with its own electric motor, both motors being piloted in frequency. The pulleys are connected to springs which pull the thread-guide towards the centre of its run and which alternatingly accumulate and release energy with every run of the thread-guide.

1 . A thread-guide device ( 14 ) for the collection of yarns on a bobbin ( 10 ), wherein the yarn (F) is distributed on the surface of the bobbin by a thread-guide ( 12 ) which moves with a back-and-forth movement parallel to the axis of the rotating roll ( 11 ) in contact with the bobbin ( 10 ), and the thread-guide device ( 14 ) is driven with a back-and-forth movement by means of a flexible element ( 15 ), to which the thread-guide ( 12 ) is fixed, the flexible element ( 15 ) being moved by two pulleys ( 16   a ,  16   b ) which move with an alternating clockwise/anticlockwise movement by the activation of an electric motor piloted in frequency, characterized in that
 the flexible element ( 15 ) is an open flexible element;   both of the pulleys ( 16   a ,  16   b ) are driving pulleys activated by at least one electric motor ( 17   a ,  17   b ) for each pulley, each motor being controlled by means of respective position detectors and piloted by a control unit, which coordinates the piloting of said motors ( 17   a ,  17   b ) to produce the desired transversing movement;   the ends of the open flexible element ( 15 ) are wound onto the two driving pulleys ( 16   a ,  16   b ), to which they are physically fixed with a constraint ( 26   a ,  26   b );   the driving pulleys ( 16   a ,  16   b ) are connected with elastic elements ( 18   a ,  18   b ;  22   a ,  22   b ;  38   a ,  38   b ), which tend to rotate them in the opposite direction to each other, bringing the thread-guide ( 12 ) to its own part and providing, for each run of said thread-guide ( 12 ), in addition to the torque exerted by the motors ( 17   a ,  17   b ), also the difference in elastic energy accumulated by the elastic elements ( 18   a ,  18   b ;  22   a ,  22   b ;  38   a ,  38   b ) in the previous run.   
   
   
       2 . The thread-guide device for the collection of yarns on a bobbin according to  claim 1 , characterized in that, in correspondence with the inversion point of the run of said thread-guide ( 12 ), both of said motors ( 17   a ,  17   b ) are contemporaneously stopped and brought to velocity in the opposite direction, with the maximum torque available, the difference in available elastic energy accumulated by the elastic elements ( 18   a ,  18   b ;  22   a ,  22   b ;  38   a ,  38   b ) in the previous run, being such as to brake and restart the thread-guide ( 12 ) in the opposite direction with an acceleration close to or higher than that of the maximum acceleration obtained by each single motor ( 17   a ,  17   b ). 
   
   
       3 . The thread-guide device for the collection of yarns on a bobbin according to  claim 1 , characterized in that the elastic elements are spring elastic elements ( 18   a ,  18   b ) which always operate under tension. 
   
   
       4 . The thread-guide device for the collection of yarns on a bobbin according to  claim 1 , characterized in that the elastic elements are torsion springs ( 22   a ,  22   b ;  38   a ,  38   b ). 
   
   
       5 . The thread-guide device for the collection of yarns on a bobbin according to  claim 4 , characterized in that the torsion springs ( 22   a ,  22   b ) are inserted between the rear extension of the driving shaft ( 45   a ,  45   b ) and the supporting structure of the relative motor ( 17   a ,  17   b ), said springs being constrained with one of their ends ( 23   a ,  23   b ) to the driving shafts ( 45   a ,  45   b ) and with the other end ( 24   a ,  24   b ) to the structure of the motor itself ( 17   a ,  17   b ). 
   
   
       6 . The thread-guide device for the collection of yarns on a bobbin according to  claim 4 , characterized in that two pulleys ( 30   a ,  30   b ;  40   a ,  40   b ) are connected to the driving pulleys ( 16   a ,  16   b ), on which two flexible transmission elements ( 31   a ,  31   b ) are fixed to one of their ends, whereas the elements ( 31   a ,  31   b ) are connected from the other end with two oscillating levers ( 34   a ,  34   b ) and connected to two torsion springs ( 38   a ,  38   b ), said springs accumulating elastic energy when the homologous pulley ( 30   a ,  30   b ;  40   a ,  40   b ) rotates and pulls its own cord ( 31   a ,  31   b ) for the rotation of its own homologous motor ( 17   a ,  17   b ), and releasing their elastic energy when said homologous pulley rotates to release its own cord ( 31   a ,  31   b ), thus supplying additional driving torque with respect to that provided by the motors ( 17   a ,  17   b ). 
   
   
       7 . The thread-guide device for the collection of yarns on a bobbin according to  claim 6 , characterized in that the two pulleys ( 30   a ,  30   b ) are coaxially assembled with the driving pulleys ( 16   a ,  16   b ). 
   
   
       8 . The thread-guide device for the collection of yarns on a bobbin according to  claim 6 , characterized in that the two pulleys ( 40   a ,  40   b ) are produced with a substantial eccentricity with respect to the axis of the driving pulleys ( 16   a ,  16   b ). 
   
   
       9 . The thread-guide device for the collection of yarns on a bobbin according to  claim 8 , characterized in that the two pulleys ( 40   a ,  40   b ) are produced with an eccentricity with respect to the axis of the driving pulleys ( 16   a ,  16   b ) which has the minimum value of the application arm of the force exerted by the cords ( 31   a ,  31   b ) on their pulley ( 40   a ,  40   b ) in correspondence with the centre point of the run of the thread-guide ( 12 ) and the maximum value of said arm in correspondence with the end points ( 41   a ,  41   b ) of the excursion of the thread-guide ( 12 ). 
   
   
       10 . The thread-guide device for the collection of yarns on a bobbin according to  claim 1 , characterized in that the motors ( 17   a ,  17   b ) are synchronous brushless or step-by-step motors, coordinatingly piloted by a control unit of the yarn winding station.