Machine and method of forming yarn package

A yarn package forming machine for winding a yarn on a bobbin to form a yarn package on said bobbin, comprising:

• a stationary frame structure;
• a pair of supporting arms disposed in spaced-apart and parallel relationship with each other and supported on said stationary structure, said supporting arms being rockable around their rock axes;
• rocking means for rocking said supporting arm around their rock axes;
• a pair of bobbin holders each rotatably supported on each of said supporting arms with its own rotation axis in parallel relationship with each of said rock axes of said supporting arms, said bobbin having a rotation axis held in coaxial relationship with said rotation axes of said bobbin holders;
• a friction roller spaced apart from said bobbin holders and having a rotation axis in parallel with said rotation axes of said bobbin holders, said supporting arms being rockable around their rock axes to have said bobbin holders and said friction roller relatively moved to assume two different operation positions consisting of a winding position where said bobbin is held in frictional contact with said friction roller and driven to rotate by said friction roller to have said yarn wound thereon and a package releasing position where said yarn package is held out of frictional contact with said friction roller to release said yarn package from said bobbin holder;
• yarn traversing means for traversing said yarn along said axes of said bobbin and said bobbin holder within a traverse width while said yarn is being wound and formed into said yarn package on said bobbin until said yarn is formed into a full yarn package;
• yarn releasing means for releasing said yarn from said yarn traversing means to form a bunch winding portion on said full yarn package after said yarn is disengaged out of said yarn traversing means;
• yarn end forming means for forming a yarn end portion including a first trailing yarn end portion trailing to said bunch winding portion to be wound on said full yarn package at a predetermined angle with respect to the axis of said bobbin, and a second trailing yarn end portion to be wound axially outwardly of said yarn package on said bobbin;
• said yarn end forming means comprising:
• a yarn transferring member positioned upstream of said bobbin and movable along the axes of said bobbin and said bobbin holder to transfer said yarn axially outwardly of the axial width of said full yarn package to form said yarn end portion on said bobbin after said bunch winding portion is formed on said full yarn package of said bobbin,
• a yarn retaining unit positioned between said bobbin and the path of said yarn transferring member and operable to have said yarn retained after said yarn end portion is formed on said bobbin, and
• a yarn cutting unit positioned between the path of said yarn transferring member and said yarn retaining unit and operable to have said yarn cut under the state that said yarn is retained by said yarn retaining unit.

A yarn package forming method of winding a yarn on a bobbin to form a yarn package on said bobbin in a yarn package forming machine comprising:

• a stationary frame structure;
• a supporting arm supported on said stationary structure and rockable around its rock axis;
• rocking means for rocking said supporting arm around its rock axis;
• a bobbin holder rotatable supported on said supporting arm with its own rotation axis in parallel relationship with said rock axis of said supporting arm, said bobbin having a rotation axis held in coaxial relationship with said rotation axis of said bobbin holder;
• a friction holder spaced apart from said bobbin holder and having a rotation axis in parallel with said rotation axis of said bobbin holder, said supporting arm being rockable around its rock axis to have said bobbin holder and said friction roller relatively moved to assume two different operation positions consisting of a winding position where said bobbin is held in frictional contact with said friction roller and driven to rotate by said friction roller to have said yarn wound thereon and a package releasing position where said yarn package is held out of frictional contact with said friction roller to release said yarn package from said bobbin holder;
• yarn traversing means for traversing said yarn along said axes of said bobbin and said bobbin holder within a traverse width while said yarn is being wound and formed into said yarn package on said bobbin until said yarn is formed into a full yarn package;
• yarn releasing means for releasing said yarn from said yarn traversing means to form a bunch winding portion on said full yarn package after said yarn is disengaged out of said yarn traversing means;
• yarn end forming means for forming a yarn end portion including a first trailing yarn end portion trailing to said bunch winding portion to be wound on said full yarn package at a predetermined angle with respect to the axis of said bobbin, and a second trailing yarn end portion to be wound axially outwardly of said yarn package on said bobbin;
• said yarn end forming means comprising:
• a yarn transferring member positioned upstream of said bobbin and movable along the axes of said bobbin and said bobbin holder to transfer said yarn axially outwardly of the axial width of said full yarn package to form said yarn end portion on said bobbin after said bunch winding portion is formed on said full yarn package of said bobbin, a yarn retaining unit positioned between said bobbin and the path of said yarn transferring member and operable to have said yarn retained after said yarn end portion is formed on said bobbin, and a yarn cutting unit positioned between the path of said yarn transferring member and said yarn retaining unit and operable to have said yarn cut under the state that said yarn is retained by said yarn retaining unit;
• said method comprising:
• a yarn winding step of winding said yarn on said bobbin to form a yarn package thereon while said bobbin is being rotated with said yarn being traversed in a direction substantial parallel with the rotation axis of said bobbin within a predetermined traverse width of is traverse motion, said bobbin having an axial end portion axially outwardly of said yarn package;
• a yarn releasing step of releasing said yarn from said traverse motion of said yarn to form a bunch winding portion on said yarn package after said yarn winding step is finished;
• a bunch winding portion forming step of forming said bunch winding portion on said yarn package after said yarn is released from said traverse motion of said yarn and
• a yarn end forming step for forming a yarn end portion including a first trailing yarn end portion trailing to said bunch winding portion to be wound on said yarn package at a predetermined angle with respect to the axis of said bobbin, and a second trailing yarn end portion to be wound on said axial end portion of said bobbin,
• said yarn end forming step comprising the steps of:
• transferring said yarn to said axial end portion of said bobbin with said yarn transferring member to wind said first trailing yarn end portion on said yarn package and to wind said second yarn end portion on said axial end portion of said bobbin after said bunch winding portion is formed on said package;
• retaining part of said trailing yarn end portion of said yarn with said retaining unit at a position between said bobbin and the path of said yarn transferring member;
• cutting part of said second trailing yarn end portion of said yarn at a position between said retaining unit and the path of said yarn transferring means;
• and
• winding said second trailing yarn end portion of said yarn on said axial end portion of said bobbin by a predetermined number of turns by unwinding part of said first trailing yarn end portion and said bunch winding portion from said yarn package under the state that said second trailing yarn end portion is retained while a tension is imparted thereto.