Spinning apparatus, air spinning apparatus in particular, with continuous adjustment of a yarn accumulation system and related method of continuous adjustment of a yarn accumulation system in a spinning apparatus

A spinning apparatus with continuous adjustment of a yarn accumulation system comprising at least one spinning head comprising:

• a spinning device comprising a spinning chamber for yarn production,
• a reel on which yarn produced by the spinning device is wound, the reel being rotatably influenced by a yarn guide shaped to impart a rotation movement of the reel for winding the yarn and a traversing movement of the yarn in winding on the reel,
• an accumulation device of the yarn produced, the accumulation device arranged between the spinning device and the reel and shaped to create a reservoir of yarn not wound on the reel,
• a joining device configured to join together a first yarn end associated with the spinning device and a second yarn end associated with the reel, and
• a processing and control unit programmed to control the yarn guide according to a spinning pattern, to adjust accordingly an amount of yarn accumulated in the accumulation device, wherein the processing and control unit is programmed such that:
• during a spinning cycle, the reel spins with a yarn extraction speed of the yarn output from the spinning device varying between a minimum and a maximum value,
• the yarn from the accumulation device is fed to the joining device where the yarn from the accumulation device is joined to the yarn output from the reel,
• the yarn output from the spinning chamber, during the time of a reattachment cycle, is deposited in the accumulation device,
• spinning of the spinning device is resumed at an end of yarn joining by the joining device, and the amount of yarn accumulated in the accumulation device is adjusted by adjusting a rotation speed or a collection speed of the reel to:
• reduce the amount of yarn accumulated below a threshold value, and
• make a winding tension as regular as possible, preventing yarn from falling or increasing beyond a certain predetermined percentage value, as a function of an unwinding or filling phase of the accumulation device, and
• after an initial unwinding of the accumulating device following a yarn re-attachment phase, an optimal value of a reel extraction speed is determined by:
• a) reducing the rotation speed of the reel by a value proportional to a duration of the initial unwinding of the accumulation device,
• b) storing the rotation speed of the reel as a first reel pulling speed V1 when a yarn presence sensor detects the presence of the yarn,
• c) storing the rotation speed of the reel as a second reel pulling speed V2 when the yarn presence sensor no longer detects the presence of the yarn, and
• d) at each change of a status of the yarn presence sensor, updating the stored first or second reel pulling speed, respectively, in the presence or absence of yarn.

A spinning apparatus with continuous adjustment of a yarn accumulation system comprising at least one spinning head comprising:

• a spinning device comprising a spinning chamber for yarn production,
• a reel on which yarn produced by the spinning device is wound, the reel being rotatably influenced by a yarn guide shaped to impart a rotation movement of the reel for winding the yarn and a traversing movement of the yarn in winding on the reel,
• an accumulation device of the yarn produced, the accumulation device arranged between the spinning device and the reel and shaped to create a reservoir of yarn not wound on the reel,
• a joining device configured to join together a first yarn end associated with the spinning device and a second yarn end associated with the reel, and
• a processing and control unit programmed to control the yarn guide according to a spinning pattern, to adjust accordingly an amount of yarn accumulated in the accumulation device, wherein the processing and control unit is programmed to:
• vary tension of the yarn accumulating in the accumulation device by modifying a linear speed of accumulation by a positive and settable percentage to allow the accumulation of coils of the yarn to be compacted and to allow unwinding of the yarn with consistent output,
• compensate for the varying tension by changing a course of the yarn guide to maintain a selected extraction speed for formation of the reel;
• terminate a yarn joining operation at an instant t=t0 and begin to unwind the yarn in the accumulation device;
• activate a yarn presence sensor;
• increase a rotation or collection speed of the reel to rapidly unwind yarn from the accumulation device;
• deactivate the yarn presence sensor at an instant t=t1 when the accumulation device has been unwound beyond a target reserve level;
• store the collection or rotation speed of the reel VMAX=V1, and reduce the collection speed to increase the target reserve level of yarn accumulation;
• activate the yarn presence sensor at an instant t=t2 when the accumulation device exceeds the target reserve level;
• and
• store the collection speed VMIN=V2, and adjust the collection speed to an average VAV value between VMIN and VMAX.

A spinning apparatus with continuous adjustment of a yarn accumulation system comprising at least one spinning head comprising:

• a spinning device comprising a spinning chamber for yarn production,
• a reel on which yarn produced by the spinning device is wound, the reel being rotatably influenced by a yarn guide shaped to impart a rotation movement of the reel for winding the yarn and a traversing movement of the yarn in winding on the reel,
• an accumulation device of the yarn produced, the accumulation device arranged between the spinning device and the reel and shaped to create a reservoir of yarn not wound on the reel,
• a joining device configured to join together a first yarn end associated with the spinning device and a second yarn end associated with the reel,
• at least two yarn presence sensors located at a first distance from each other, and
• a processing and control unit programmed to control the yarn guide according to a spinning pattern, to adjust accordingly an amount of yarn accumulated in the accumulation device, wherein the processing and control unit is programmed to perform a first self-adjusting step after an initial unwinding of the accumulation device following a yarn re-attachment phase, wherein the first self-adjusting step includes varying a rotation speed and accumulation of the reel to keep the amount of yarn accumulated on the reel within predefined limits of the at least two yarn presence sensors by:
• terminating joining of the first and second yarn ends at an instant t=t0 when the yarn produced until the instant t=t0 has been accumulated in the accumulation device, and when the at least two yarn presence sensors both detect the presence of material;
• starting the initial unwinding of the accumulation device by activating a winding or collection cylinder with a speed greater than a nominal speed;
• storing the corresponding collection speed value VMAX of the collection or winding cylinder at an instant t=t1 when a first yarn presence sensor of the at least two yarn presence sensors no longer detects material;
• unwinding the accumulation device to reach the minimum yarn presence level detected by a second yarn presence sensor of the at least two yarn presence sensors at an instant t=t2;
• storing the current speed VMIN at an instant t=t3 when the accumulation device has accumulated sufficient yarn to be detected by the first yarn presence sensor;
• calculating an average speed VAV=(VMAX+VMIN)/2;
• and
• applying the average speed value (VAV) to rotation of the collection or winding cylinder.