Yarn piecing arrangement for an open-end friction spinning machine

Piecing apparatus for piecing a yarn at an open-end friction spinning unit of the type having at least one spinning unit operable at a normal operating speed with:

• drivable friction surface means defining a yarn formation zone,
• driving means for driving the friction surface means,
• fiber feeding means for feeding separated fibers to the yarn formation zone,
• yarn withdrawal means for withdrawing formed yarn from the yarn formation zone,
• suction means for applying suction forces to the yarn formation zone,
• and yarn winding means for winding the spun yarn on a spool, said piecing apparatus comprising:
• yarn end inserting means for inserting a yarn end into the spinning unit,
• friction effect control means for controlling the friction effect of the friction surface means,
• fiber feed control means for controlling the quantity of fed fibers,
• yarn end withdrawal means for withdrawing the yarn end and attached piecing with newly spun yarn,
• piecing section cut out means for cutting out the piece of yarn containing the yarn piecing,
• splicing means for making a splicing connection between the newly formed yarn end and a yarn end connected with the spool,
• adjusting means for selectively reducing the spinning unit operating speed to a speed below the normal operating speed during the making of a splicing connection by the splicing means,
• yarn storage device means for temporarily storing the newly formed yarn during the making of a splicing connection by the splicing means,
• winding control means for controlling the winding into the spool,
• and program control means for controlling the individual operating means such that the formation of the yarn piecing and splicing connection occurs at a lower production speed as compared to normal spinning operation,
• said program control means including means for controlling the individual operating means such that, after the formation of the splicing connection, winding takes place at a speed exhibiting a difference, with respect to the speed of the yarn end withdrawal means for piecing, which is larger than the difference between the winding and yarn withdrawal speeds during the normal spinning operations,
• said spinning units each being equipped with a channel which leads into the area of the yarn formation zone facing away from the yarn withdrawal means, said channel being selectively connectible to an air supply connection of the servicing unit.

Piecing apparatus for piecing a yarn at an open-end friction spinning unit of the type having at least one spinning unit with:

• a pair of friction rollers arranged adjacent one another to form a wedge-shaped yarn forming gap,
• friction roller driving means for driving the friction rollers in the same rotational direction during spinning operations,
• fiber feeding means for feeding separated fibers to the yarn forming gap,
• yarn withdrawal means for withdrawing formed yarn from the yarn forming gap,
• suction means for applying suction forces to the yarn forming gap,
• and yarn winding means for winding the spun yarn on a spool, said piecing apparatus comprising:
• yarn end inserting means for inserting a yarn end into the spinning unit,
• friction effect control means for controlling the friction effect of the rollers,
• fiber feed control means for controlling the quantity of fed fibers,
• yarn end withdrawal means for withdrawing the yarn end and attached piecing with newly spun yarn,
• piecing section cut out means for cutting out the piece of yarn containing the yarn piecing,
• splicing means for making a splicing connection between the newly formed yarn end and a yarn end connected with the spool,
• yarn storage device means for temporarily storing the newly formed yarn during the making of a splicing connection by the splicing means,
• winding control means for controlling the winding onto the spool,
• and program control means for controlling the individual operating means such that the formation of the yarn piecing and splicing connection occurs at a lower production speed as compared to normal spinning operation,
• said control means including means for controlling the individual operating means such that, after the formation of the splicing connection, winding takes place at a speed exhibiting a difference, with respect to the speed of the yarn end withdrawal means for piecing, which is larger than the difference between the winding and yarn withdrawal speeds during the normal spinning operations,
• said yarn storage device means being subdivided in the travel direction of the yarn into several chambers located one behind the other, which chambers are selectively connectable to a vacuum source.

Piecing apparatus for piecing a yarn at an open-end friction spinning unit of the type having at least one spinning unit with:

• a pair of friction rollers arranged adjacent one another to form a wedge-shaped yarn forming gap,
• friction roller driving means for driving the friction rollers in the same rotational direction during spinning operations,
• fiber feeding means for feeding separated fibers to the yarn forming gap,
• yarn withdrawing means for withdrawing formed yarn from the yarn forming gap,
• suction means for applying suction forces to the yarn forming gap,
• and yarn winding means for winding the spun yarn on a spool, said piecing apparatus comprising:
• yarn end inserting means for inserting a yarn end into the spinning unit,
• friction effect control means for controlling the friction effect of the rollers,
• fiber feed control means for controlling the quantity of fed fibers,
• yarn end withdrawal means for withdrawing the yarn end and attached piecing with newly spun yarn,
• piecing section cut out means for cutting out the piece of yarn containing the yarn piecing,
• splicing means for making a splicing connection between the newly formed yarn end and a yarn end connected with the spool,
• yarn storage device means for temporarily storing the newly formed yarn during the making of a splicing connection by the splicing means,
• winding control means for controlling the winding onto the spool,
• and program control means for controlling the individual operating means such that the formation of the yarn piecing and splicing connection occurs at a lower production speed as compared to normal spinning operation,
• said program control means including means for controlling the individual operating means such that, after the formation of the splicing connection, winding takes place at a speed exhibiting a difference, with respect to the speed of the yarn end withdrawal means for piecing, which is larger than the difference between the winding and yarn withdrawal speeds during the normal spinning operations,
• said spinning units being each equipped with a channel which leads into the area of the wedge-shaped gap facing away from the yarn withdrawal means, said channel being selectively connectible to an air supply connection of the servicing unit.