Method for braking a weft thread of a weaving machine

Abstract

The invention relates to a method ( 1 ) for braking a weft thread ( 3 ) of a jet weaving machine ( 10 ), in said method ( 1 ) a braking element ( 2 ) being brought into contact with the weft thread ( 3 ), with the braking element ( 2 ) being moved by means of a drive ( 21 ) in accordance with a predeterminable distance/time plot so that the weft thread ( 3 ) is deflected by the braking element ( 2 ) in accordance with a position function ( 23 ), so that the weft thread ( 3 ) is braked in accordance with a braking profile ( 31 ), characterized in that the position function ( 23 ) is matched to the braking profile ( 31 ) of the weft thread ( 3 ).

1 . Method for braking a weft thread ( 3 ) of a jet weaving machine, in which a braking element ( 2 ) is brought into contact with the weft thread ( 3 ), the braking element ( 2 ) is moved by means of a drive ( 21 ) in accordance with a predeterminable distance/time plot so that the weft thread ( 3 ) is deflected by the braking element ( 2 ) in accordance with a position function ( 23 ) and the weft thread ( 3 ) is braked in accordance with a braking profile ( 31 ), characterized in that the position function ( 23 ) is matched to the braking profile ( 31 ) of the weft thread ( 3 ).  
   
   
       2 . Method in accordance with  claim 1 , with the weft thread ( 3 ) being deflected in accordance with the position function ( 23 ) in an initial braking phase ( 11 ) by the braking element ( 2 ) with a continuously increasing speed from a rest position ( 111 ) into a first position ( 112 ) and, in a final braking phase, ( 12 ) being brought back from a second position ( 121 ) into the rest position ( 111 ) with continuously diminishing speed.  
   
   
       3 . Method in accordance with  claim 1 , with the weft thread ( 3 ) being moved in an intermediate braking phase ( 13 ) out of the first position ( 112 ) into a maximum position ( 113 ) and being moved back out of the maximum position ( 113 ) into the second position ( 121 ).  
   
   
       4 . Method in accordance with  claim 1 , with the position of the weft thread ( 3 ) remaining substantially constant in the intermediate braking phase ( 13 ) over a predetermined period of time.  
   
   
       5 . Method in accordance with  claim 1 , with the distance/time plot of the braking element being linearly predetermined at least section-wise.  
   
   
       6 . Method in accordance with  claim 1 , with the position function ( 23 ) of the weft thread ( 3 ) being an asymmetrical position function.  
   
   
       7 . Method in accordance with  claim 1 , with the position function ( 23 ) of the weft thread ( 3 ) being predetermined in at least one of the braking phases by a real or complex trigonometric position function.  
   
   
       8 . Method in accordance with  claim 1 , with the position function ( 23 ) being a hyperbolic tangent function.  
   
   
       9 . Method in accordance with  claim 1 , with the braking element ( 2 ) being moved by a motor, in particular by an electric motor, or by a magnet, in particular by an electromagnet, or by a mechanical drive.  
   
   
       10 . Jet weaving machine, in particular an air jet weaving machine ( 10 ), including a braking element ( 2 ) for braking a weft thread ( 3 ), with the braking element ( 2 ) being designed and arranged in such a manner that it can be brought into contact with the weft thread ( 3 ) and can be moved by means of a drive ( 21 ) in accordance with a predeterminable distance/time plot, with the weft thread ( 3 ) being deflectable by the braking element ( 2 ) in accordance with a position function ( 23 ) and with it being possible to brake the weft thread ( 3 ) in accordance with a braking profile ( 31 ), characterized in that the position function ( 23 ) can be matched to the braking profile ( 31 ) of the weft thread ( 3 ).  
   
   
       11 . Jet weaving machine in accordance with  claim 10 , with a control unit ( 4 ) being provided for controlling and/or regulating the drive ( 21 ), by means of which the drive ( 21 ) can be controlled in such a manner that in an initial braking phase ( 11 ) the weft thread ( 3 ) can be deflected with continuously increasing speed from a rest position ( 111 ) into a first position ( 112 ) and can be brought in a final braking phase ( 12 ) from a second predeterminable position ( 121 ) back into the rest position ( 111 ) with continuously diminishing speed.  
   
   
       12 . Jet weaving machine in accordance with  claim 10 , with a magnet, in particular an electromagnet, a motor, in particular an electric motor, or a mechanical drive being provided as the drive ( 21 ) of the braking element ( 2 ), and with the braking element ( 2 ) being provided as a hoop element or as a twistable fork element.