Automatic doffing method

A method of automatically doffing a strand package off of a rotating collet of a collet winder wherein yarn is supplied to said collet from a gathering ring and wound upon said collet by a traversing guide to form a strand package, said method comprising the steps of:

• providing a horizontal row of said collet winders each having a collet and an associated traversing guide;
• providing a plurality of receiving stations for receiving said strand packages when doffed from said collet winders;
• providing a variable speed rotating doffing cup having an inflatable cup liner expandable to grip said strand package;
• moving said doffing cup along a path generally along said row of collet winders and back and forth from said collet winders and receiving stations;
• positioning said doffing cup in an approach position in front of a strand package to be doffed with an axis of rotation of said doffing cup parallel and coincident with the axis of rotation of said strand package;
• extending said doffing cup over said full strand package to a doff position and rotating said doffing cup at a speed generally equal to or greater than the rotational speed of said rotating collet and strand package;
• inflating said inflatable cup liner of said doffing cup when said doffing cup is in said doff position to grip the strand package firmly around its circumference;
• retracting said doffing cup and strand package along the axis of rotation of said doffing cup and collet to remove said strand package from said collet while said strand package is rotating with said doffing cup;
• severing the strand package extending from said rotating doffed strand package to said collet;
• braking said rotational speed of said rotating doffing cup and strand package after removal from said collet;
• and
• depositing said strand package at said receiving station by deflating said inflatable liner of said doffing cup after said rotation of said doffing cup has been braked.

A method of producing a continuous strand of glass fibers of the type which includes producing glass fibers continuously, collecting said glass fibers in a single strand, advancing the strand to a rotating collet, causing the strand to traverse the collet back and forth along the length of the collet to form a strand package, wherein the improvement comprises:

• providing a rotating doffing cup having a hollow cylindrical interior with an actuatable gripping means carried about the circumference of said cylidrical interior;
• positioning said doffing cup at a preset approach position in front of a full strand package so that the axis of rotation of the doffing cup is parallel to and coincident with the axis of rotation of the collet;
• extending said doffing cup to a doff position in which the doffing cup generally encloses the strand package along generally the entire length thereof while rotating said doffing cup at a speed generally equal to the rotational speed of said full strand package;
• actuating said gripping means when said doffing cup is in said doffing position so that said strand package is gripped around its entire circumference and firmly held by said doffing cup;
• retracting said doffing cup and strand package along said axes of rotation causing said rotating strand package to be doffed off of said rotating collet;
• producing a strand extending from said doffed strand package to said collet;
• severing said strand extending from said strand package to said collet as said rotating doffing cup and strand package are retracted producing a tail strand on said strand package and a tail strand on said collet;
• depositing said doffed strand package at a receiving station;
• and
• forming windings on said collet to form a new strand package without stopping rotation of said collet.