Method for automatically piecing a thread at a workstation of a textile machine, and textile machine

A method for automatically piecing a thread at a workstation of a textile machine, comprising:

• seeking an end of the thread on a surface of a bobbin with a suction nozzle;
• unwinding the thread from the bobbin counter to a regular draw-off direction of the thread and sucking the thread into the suction nozzle;
• driving the bobbin in a direction of reverse rotation with a drive for the unwinding of the thread;
• draw-opening a thread loop in the thread and moving the thread loop towards a piecing unit via movement of a feeder unit;
• driving the bobbin in the direction of reverse rotation during the drawing-open of the thread loop such that the thread is unwound from the bobbin;
• and
• coordinating a speed of the reverse rotation of the bobbin with movement of the feeder unit;
• and
• wherein the reverse rotation speed of the bobbin is coordinated such that at all time during the reverse rotation of the bobbin, a thread length withdrawn from the bobbin is greater than a thread length required for forming the thread loop.

A textile machine comprising a workstation, the workstation further comprising:

• a suction nozzle for seeking an end of a thread on a surface of a bobbin and sucking in the thread;
• a drive configured to drive the bobbin such that the thread is withdrawn from the bobbin counter to a regular draw-off direction of the thread;
• a piecing unit;
• a feeder unit configured to drawn-open a thread loop in the thread withdrawn from the bobbin and move the thread loop towards the piecing unit, the feeder unit pivotably arranged at the workstation to account for a varying speed of the yarn transported by the feeder unit during movement of the feeder unit;
• a controller configured for operating the drive in a direction of reverse rotation during the draw-opening of the thread loop such that the thread is unwound from the bobbin and a speed of the reverse rotation of the bobbin is tied with movement of the feeder unit;
• and
• wherein the reverse rotation speed of the bobbin is controlled such that at all time during the reverse rotation of the bobbin, a thread length withdrawn from the bobbin is less than a thread length required for forming the thread loop.

A method for automatically piecing a thread at a workstation of a textile machine, comprising:

• seeking an end of the thread on a surface of a bobbin with a suction nozzle;
• unwinding the thread from the bobbin counter to a regular draw-off direction of the thread and sucking the thread into the suction nozzle;
• driving the bobbin in a direction of reverse rotation with a drive for the unwinding of the thread;
• draw-opening a thread loop in the thread and moving the thread loop towards a piecing unit via movement of a feeder unit;
• driving the bobbin in the direction of reverse rotation during the drawing-open of the thread loop such that the thread is unwound from the bobbin;
• and
• coordinating a speed of the reverse rotation of the bobbin with movement of the feeder unit;
• and
• wherein the drive is driven according to a speed profile during movement of the feeder unit.