Winder of synthetic yarn, cheese-like yarn package of synthetic yarn, and method for winding the same

A winder for winding a synthetic yarn at a constant speed, characterized in that said winder is comprised of:

• a bobbin shaft having a bobbin mounted thereon for winding a synthetic yarn;
• bobbin shaft driving means, operably connected to a first inverter, for rotating said bobbin shaft;
• a traverse device comprising a cylindrical multi-track cam with a circumferential face arranged with an endless groove consisting of a plurality of inclined pathways and a plurality of folded pathways, each said folded pathway having a return point connected with a respective one of said inclined pathways, said return points of said folded pathways being arranged at different positions with respect to one another in the axial direction of said cylindrical cam;
• a contacting roll arranged in a direction parallel to an axis of said bobbin shaft such that said contacting roll is movable into contact with a circumferential face of a yarn package wound on said bobbin;
• contacting roll driving means, operably connected to a second inverter independent of said first inverter, for rotating said contacting roll;
• rotational speed detecting means for detecting a rotational speed of said contacting roll;
• and
• controller means, connected electrically with said bobbin shaft driving means and said rotational speed detecting means, for controlling a rotational speed of said bobbin shaft through said bobbin shaft driving means in accordance with said detected rotational speed of said contacting roll;
• and
• said second independent inverter not being connected to said controller means.

A method for winding a yarn, at a constant speed of at least about 5,000 m/min, into a cheese yarn package, comprising the steps of:

• rotating, via a first electrically powered drive means and associated first independent inverter, a contacting roll at a target winding speed;
• rotating, via a second electrically powered drive means and associated second independent inverter, a bobbin mounted on a bobbin shaft to wind the yarn onto the bobbin;
• contacting the outer surface of the contacting roll with the outer surface of the yarn package at a contact pressure of less than about 0.2 kg/cm;
• detecting the rotational speed of the contacting roll in contact with the yarn package;
• and
• controlling the rotational speed of the bobbin and bobbin shaft in accordance with the detected rotational speed of the contacting roll to maintain the circumferential velocity of the outer surface of the contacting roll substantially constant and equal to the target winding speed, said target winding speed corresponding to the circumferential velocity of the outer surface of the yarn package wound on the bobbin;
• and
• independently rotating the contacting roll via the first independent inverter so that a torque applied from the outer surface of the yarn package to the contacting roll is minimized.

A method for winding a yarn, at a constant speed of at least about 5,000 m/min, into a cheese yarn package, comprising the steps of:

• rotating, via a first electrically powered drive means and associated first independent inverter, a contacting roll at a target winding speed;
• rotating, via a second electrically powered drive means and associated second independent inverter, a bobbin mounted on a bobbin shaft to wind the yarn onto the bobbin;
• contacting the outer surface of the contacting roll with the outer surface of the yarn package at a contact pressure of less than about 0.2 kg/cm;
• guiding the yarn onto the bobbin with a multi-track cam traverse device;
• forming a pair of end portions on the wound yarn package having a higher hardness than the remainder of the wound yarn package by periodically returning a traverse motion of the multi-track cam device at said pair of end portions;
• detecting the rotational speed of the contacting roll in contact with the yarn package;
• and
• controlling the rotational speed of the bobbin and bobbin shaft in accordance with the detected rotational speed of the contacting roll to maintain the circumferential velocity of the outer surface of the contacting roll substantially constant and equal to the target winding speed, said target winding speed corresponding to the circumferential velocity of the outer surface of the yarn package wound on the bobbin;
• and
• independently rotating the contacting roll via the first independent inverter so that a torque applied from the outer surface of the yarn package to the contacting roll is minimized.