Method for holding taut a weft thread and a loom for carrying out said method

Abstract

The invention relates to a method for the taut-holding of the weft thread ( 15 ) in the mixing tube ( 4 ) of the main nozzle ( 1 ) of an air jet loom, and an air jet loom for the carrying out of the method. The invention has the underlying technical object of avoiding an air stream effective over nearly the total length of the main nozzle ( 1 ) and disadvantageously influencing the structure of the weft thread ( 5 ) during its idle phase in the main nozzle ( 1 ), and nonetheless holding the weft thread ( 5 ) taut in the main nozzle ( 1 ). This is achieved in that the air stream, during the idle phase of the weft thread ( 5 ), impinges on only its front end ( 5 a ) in the mixing tube of the main nozzle.

1 . Method for the taut-holding of the weft thread in the mixing tube of the main nozzle of an air jet loom, whereby a length section of a weft thread supplied from preferably a pre-spooling device is impinged on by an air stream exerting a tension force onto the weft thread in the mixing tube of the main nozzle during a predetermined time duration, which air stream is at a predetermined pressure level, characterized in that the air stream impinges on the end region ( 5   a ) of the length section at an angle to the longitudinal center axis ( 4   a ) of the mixing tube ( 4 ) during the predetermined time duration.  
   
   
       2 . Method according to  claim 1 , characterized in that the predetermined time duration corresponds to at least the duration of one weaving cycle.  
   
   
       3 . Method according to  claim 1 , characterized in that the air stream is emitted at an acute angle to the longitudinal center axis ( 4   a ) of the mixing tube ( 4 ).  
   
   
       4 . Method according to  claim 1 , characterized in that the air stream is emitted at a right angle to the longitudinal center axis ( 4   a ) of the mixing tube ( 4 ).  
   
   
       5 . Method according to  claim 1 , characterized in that the air stream is emitted at an obtuse angle to the longitudinal center axis ( 4   a ) of the mixing tube ( 4 ).  
   
   
       6 . Method according to  claim 1 , characterized in that the end region ( 5   a ) of the length section impinged on by the air stream is cut-off after the weaving-in of the weft thread ( 5 ) in a woven fabric.  
   
   
       7 . Air jet loom for the carrying out of the method according to  claim 1 , encompassing at least one pneumatically impingeable weft thread insertion means comprising a mixing tube ( 4 ), at least one controllable valve operatively connected via a pressure line with the weft thread insertion means for the impinging on a length section, which is to be held taut at least in the mixing tube ( 4 ), of the weft thread supplied from preferably a pre-spooling device, with a predetermined pressure level of an air stream, at least one pneumatic pressure source and a memory programmable loom controller ( 11 ) for the controlled activation of the at least one controllable valve, characterized in that the mixing tube ( 4 ) in the area of its free end comprises an arrangement, that deflects the front end ( 5   a ) of the weft thread ( 5 ) out of the plane of the longitudinal center axis ( 4   a ) of the mixing tube ( 4 ) by means of the air stream.  
   
   
       8 . Air jet loom according to  claim 7 , characterized in that the arrangement encompasses an inlet channel ( 6 ) with outlet ( 6   a ) penetrating through the wall ( 4   b ) of the mixing tube ( 4 ) and an inlet ( 7   a ) of an outlet channel ( 7 ) arranged lying diametrically opposite the outlet ( 6   a ) of the inlet channel ( 6 ).  
   
   
       9 . Air jet loom according to  claim 7 , characterized in that the arrangement encompasses a connection piece ( 16 ) connectable with the free end of the mixing tube ( 4 ), with an inlet channel ( 16   a ) with outlet ( 16   a ′) and an inlet ( 16   b ′) of an outlet channel ( 16   b ) arranged lying diametrically opposite the outlet ( 16   a ′) of the inlet channel ( 16   a ).  
   
   
       10 . (canceled)  
   
   
       11 . Air jet loom according to  claim 8 , characterized in that the longitudinal center axis ( 17 ) of the inlet and outlet channel ( 6 ,  7 ) is oriented preferably perpendicularly to the longitudinal center axis ( 4   a ) of the mixing tube channel ( 4 ).  
   
   
       12 . Air jet loom according to  claim 9 , characterized in that the longitudinal center axis ( 17 ) of the inlet and outlet channel ( 6 ,  7 ) is oriented preferably perpendicularly to the longitudinal center axis ( 4   a ) of the mixing tube channel ( 4 ).