Method for Avoiding Ribbon Windings

Abstract

A method for avoiding ribbon windings in producing cross-wound bobbins at the workstations of textile machines in the “random winding” type of winding, by changing the traversing speed at which the thread is wound onto the bobbin. Each workstation has a single motor drive activated for the rotation of the cross-wound bobbin, and a single motor drive activated for a traversing thread guide. The diameters (D SP k ) of the bobbin ( 8 ) which are critical with regarding to the development of ribbon windings depending on the width (B Sp ) of the bobbin ( 8 ) and a cross-winding angle (α) are determined, and, shortly before reaching each critical diameter (D SP k ), the cross-winding angle (α) is changed to a value (α 1 ), which avoids development of ribbon windings in this diameter region, and the cross-winding angle (α 1 ) is reset to its original value (α) after the critical diameter (D SP k ) has been passed.

1 . Method for avoiding ribbon windings in the production of take-up bobbins which are wound at the workstations of textile machines producing cross-wound bobbins in the “random winding” type of winding, by changing the traversing speed at which the yarn is wound onto the take-up bobbin, the workstations in each case having a single motor drive, which can be activated in a defined manner for the rotation of the cross-wound bobbin, and a single motor drive which can be activated in a defined manner for a traversing yarn guide, characterised in that the diameters (D SP k ) of the cross-wound bobbin ( 8 ) which are particularly critical with regarding to the development of ribbon windings and depend on the width (B Sp ) of the cross-wound bobbin ( 8 ) and a cross-winding angle (α) selected during the winding of the cross-wound bobbin ( 8 ), are determined, in that, in each case, shortly before reaching one of these critical diameters (D SP k ), the cross-winding angle (α) is changed to a value (α 1 ), which rules out the development of ribbon windings in this diameter region and in that the cross-winding angle (α 1 ) is reset again to its original value (α) after the critical diameter (D SP k ) has been passed. 
   
   
       2 . Method according to  claim 1 , characterised in that the critical diameters (D SP k ) of the cross-wound bobbin ( 8 ) are determined according to the formula (D SP k )=(whole number) x bobbin width (B Sp )/π×tan of half the cross-winding angle (α/2). 
   
   
       3 . Method according to  claim 1 , characterised in that the cross-winding angle (α) is reduced shortly before reaching a critical diameter (D SP k ) of the cross-wound bobbin ( 8 ). 
   
   
       4 . Method according to  claim 1 , characterised in that to change the cross-winding angle (α), the speed (V FF ) of the traversing yarn guide ( 18 ) is changed, the rotational speed (V WW ) of the winding roller ( 19 ) being simultaneously adjusted in such a way that the yarn tension of the running-on yarn ( 7 ) remains virtually constant. 
   
   
       5 . Method according to  claim 4 , characterised in that a stepping motor ( 20 ) is used as the drive for the traversing yarn guide ( 18 ).