Process for preparing a piecing operation in an air jet spinning arrangement

A method of piecing a fibre strand fed to an air jet assembly to form a thread, comprising the acts of:

• slowing to a stop a pair of apron rollers following a break of the fibre strand;
• slowing to a stop a pair of delivery rollers, after the apron rollers, thereby defining a starting end of the fibre strand;
• opening the pair of delivery rollers after stopping thereof;
• driving the pair of apron rollers backwards a small distance to pull back the starting end of the fibre strand;
• feeding backwards from the air jet assembly a piecing portion of the thread therein;
• starting at slow speed the pair of delivery rollers to move the piecing portion of the thread to a selected position;
• and
• starting the pair of apron rollers when the piecing portion reaches the selected position to piece together the piecing portion of the thread and the starting end of the fibre strand.

An air jet spinning device, comprising:

• an air jet assembly having a vortex chamber spinning a fibre strand therein into a thread;
• a drafting unit feeding the fibre strand to the air jet assembly;
• delivery rollers handling the fibre strand;
• and
• apron rollers feeding the fibre strand to the delivery rollers, a speed of the apron rollers being separately controllable from that of the delivery rollers;
• wherein, after a break of the thread, the delivery rollers are slowed and stopped after first slowing and stopping the apron rollers, thus placing a starting end of the fiber strand in a main drafting zone when the drive and apron rollers are stopped, and a piecing portion of the thread is moved backwards to piece with a starting end of the fibre strand, before restarting the delivery rollers and then the apron rollers.