Method for braking a weft thread of a weaving machine

Abstract

In accordance with the invention a method ( 1 ) for braking a weft thread ( 2 ) of a weaving machine ( 3 ), in particular of a jet weaving machine ( 3 ) is provided, in said method a braking element ( 4 ) is brought into contact with the weft thread ( 2 ) and the braking element ( 4 ) is moved via a control device ( 5 ) by means of a drive ( 6 ). In this arrangement, during a weft thread insertion ( 7 ) a first measurement value ( 8 ) of a movement parameter ( 9 ) of the weft thread ( 2 ) is determined, a first estimate value ( 10 ) for the movement parameter ( 9 ) is estimated on the basis of the first measurement value ( 8 ) and a correction value ( 11 ) is determined from it. The movement parameter ( 9 ) of the weft thread ( 2 ) is then corrected on the basis of the correction value ( 11 ).

1 . Method for braking a weft thread ( 2 ) of a weaving machine ( 3 ), in particular of a jet weaving machine ( 3 ), in said method a braking element ( 4 ) being brought into contact with the weft thread ( 2 ) and the braking element ( 4 ) being moved via a control device ( 5 ) by means of a drive ( 6 ), characterized in that during a weft thread insertion ( 7 ) a first measurement value ( 8 ) of a movement parameter ( 9 ) of the weft thread ( 2 ) is determined, a first estimate value ( 10 ) for the movement parameter ( 9 ) is estimated on the basis of the first measurement value ( 8 ) and a correction value ( 11 ) is determined from it; and in that the movement parameter ( 9 ) of the weft thread ( 2 ) is corrected on the basis of the correction value ( 11 ).  
   
   
       2 . Method in accordance with  claim 1 , with the determination of the first measurement value ( 8 ) of the movement parameter ( 9 ) of the weft thread ( 2 ), the estimation of the first estimate value ( 10 ), the determination of the correction value ( 11 ), and the correction of the movement parameter ( 9 ) of the weft thread ( 2 ) being carried out during one and the same weft thread insertion ( 7 ).  
   
   
       3 . Method in accordance with  claim 1 , with the movement parameter ( 9 ) of the weft thread ( 2 ) being a position ( 9 ) a speed ( 9 ), an acceleration ( 9 ), a force ( 9 ), a mechanical tension ( 9 ), a thread tension ( 9 ) or another movement parameter ( 9 ) of the weft thread ( 2 ).  
   
   
       4 . Method in accordance with  claim 1 , with the weft thread ( 2 ) being braked in such a manner that the movement parameter ( 9 ) of the weft thread ( 2 ), in particular the speed ( 9 ) of the weft thread ( 2 ), achieves a value at the end of the braking process which is within a predetermined tolerance range ( 12 ).  
   
   
       5 . Method in accordance with  claim 1 , with a second measurement value ( 8 ) being measured during the weft thread insertion ( 7 ) after the first measurement value ( 8 ), a second estimate value ( 10 ) being estimated on the basis of at least the second measurement value ( 8 ) and the movement parameter ( 9 ) of the weft thread ( 2 ) again being influenced on the basis of the second estimate value ( 10 ).  
   
   
       6 . Method in accordance with  claim 1 , with a second measurement value ( 8 ) being measured during the weft thread insertion ( 7 ) after the first measurement value ( 8 ), at least one first estimate value ( 10 ) being estimated on the basis of the first measurement value ( 8 ) and of the second measurement value ( 8 ), and the movement parameter ( 9 ) of the weft thread ( 2 ) being influenced on the basis of at least the first estimate value ( 10 ).  
   
   
       7 . Method in accordance with  claim 1 , with the correction value ( 11 ) for influencing the movement parameter ( 9 ) being formed through a comparison of the estimate value ( 10 ) with a predetermined desired profile for the movement parameter ( 9 ).  
   
   
       8 . Method in accordance with  claim 1 , with the movement parameter ( 9 ) being measured without contact by a sensor ( 14 ).  
   
   
       9 . Method in accordance with  claim 1 , with the position ( 9 ) and/or the speed ( 9 ) of the weft thread ( 2 ) being measured, in particular by an optical sensor ( 14 ).  
   
   
       10 . Method in accordance with  claim 1 , with a sensor element being provided which is brought into touching contact with the weft thread ( 2 ).  
   
   
       11 . Weaving machine, comprising a braking element ( 4 ) which can be brought into contact with a weft thread ( 2 ), with the braking element ( 4 ) being movable by means of a drive ( 6 ), and with a sensor ( 14 ) and/or a sensor element being provided for measuring a movement parameter ( 9 ) of the weft thread ( 2 ), characterized in that a control device ( 5 ) comprising a correction unit ( 51 ) is provided, with the control device ( 5 ) being connected in a signal transmitting manner to the drive ( 6 ) of the braking element ( 4 ) and being connected in a signal transmitting manner to the sensor ( 14 ) and/or the sensor element for the determination of the movement parameter ( 9 ), so that, during a weft thread insertion ( 7 ), a first measurement value ( 8 ) of the movement parameter ( 9 ) of the weft thread ( 2 ) can be read into the correction unit ( 51 ), a first estimate value ( 10 ) for the movement parameter ( 9 ) can be estimated on the basis of the first measurement value ( 8 ), a correction value ( 11 ) can be determined from it by the correction unit ( 51 ), and the movement parameter ( 9 ) of the weft thread ( 2 ) can be corrected by the braking element ( 4 ) on the basis of the correction value ( 11 ).