Introducing/removing device of the end in an open-end spinning rotor

1. Introducing/removing device of the end of the thread for an automatic service trolley for spinning units of open-end spinning machines for carrying out intervention cycles for starting, reattachment and lifting on the spinning units, said trolley carrying on-board members or groups of members dedicated to single or multiple operations of the various cycles, said introducing/removing device ( 30 ) comprising a moving structure ( 31 ), capable of taking a gripping member into various working positions to take, grip, pull, release and deliver the thread to the various members of the trolley and of the spinning machine, characterised in that its gripping member ( 32 ) consists of a pair of parallel rollers ( 32 a , 32 b ) pressed against each other according to their generatrices, and arranged with their axes substantially perpendicular to the direction of movement of the device ( 30 ) and can be moved apart from each other to take and release the thread, said rollers ( 32 a , 32 b ) being equipped with an actuation motor ( 34 ) capable of making the rollers themselves rotate in commanded rotation in the two directions and controlled in angular position and speed, to introduce and re-extract the end of the thread in the opening ( 9 ) of the rotor ( 8 ).

2. Introducing/removing device of the end of the thread according to claim 1 , characterised in that the moving structure ( 31 ) is a pantograph structure.

3. Introducing/removing device of the end of the thread according to claim 1 , characterised in that of the two rollers ( 32 a, b ) of the gripping member ( 32 ) one ( 32 a ) is motorised and the other ( 32 b ) is idle, and in that said rollers are kept pressed and closed against each other by a spring system, the actuation for causing them to open being carried out with a pneumatic cylinder ( 33 ).

4. Introducing/removing device of the end of the thread according to claim 1 , characterised in that on the axis of the motorised cylinder ( 32 a ) a brushless actuation motor ( 34 ) is arranged that is driven in frequency to obtain angular positions, speeds and accelerations that are controlled in every step of its operation in both directions of rotation, according to the driving that is imparted by the trolley control unit.

5. Introducing/removing device of the end of the thread according to claim 1 , characterised in that on the axis of the motorised cylinder ( 32 a ) a stepper actuation motor ( 34 ) is arranged that is driven in steps to obtain angular positions, speeds and accelerations that are controlled in every step of its operation in both directions of rotation, according to the driving that is imparted by the trolley control unit.

6. Introducing/removing device of the end of the thread according to claim 1 , characterised in that a centring element ( 35 ) is placed in its end that engages in an abutment ( 36 ) on the front of the spinning unit, for the precision positioning of the gripping member ( 32 ) with respect to the spinning rotor.

7. Introducing/removing device of the end of the thread according to claim 1 , characterised in that the actuation means of the device ( 30 ) for introducing and withdrawing the end from the rotor ( 8 ) to catch the new fibres from the throat of the rotor are coordinated, by the trolley control unit, with thread tautening devices so that during introduction and removal thread and end are always fully taut and cannot become entangled.

8. Introducing/removing device of the end of the thread according to claim 6 , characterised in that the thread tautening device is the device ( 41 ) for controlling the thread taken into a taut position T to go up further with a brief controlled stroke that is strictly coordinated by the trolley control unit.

9. Introducing/removing device of the end of the thread according to claim 6 , characterised in that the thread tautening device is a suction mouth that is actuated to capture the possible curve of the thread that is not taut downstream of the rotor ( 8 ).