Patent Publication Number: US-6213161-B1

Title: Holder apparatus for weft thread in a series shed weaving machine

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an arrangement for the holding of a weft thread for a series shed weaving machine and to a series shed weaving machine with an arrangement of this kind. 
     An arrangement of this kind is known from WO 96/38613. This arrangement contains two holder elements which are arranged stationarily and overlap at least section-wise, at least two ring-shaped forwarding elements which are arranged parallel to one another and at a spacing on both sides of the holder arrangement and which are movably arranged relative to the latter in order to push a weft thread which extends transversely to the direction of movement of the forwarding elements and transversely to the holder elements between the holder elements, and a stretching nozzle in order to tension the weft thread in the insertion direction. 
     The rigid association of the holder elements and the forwarding elements relative to one another, i.e. with respect to one another, proves to be disadvantageous because a holding force is present thereby which can not be changed for the use of different weft yarns without greater cost and complexity. In addition the setting is critical. 
     SUMMARY OF THE INVENTION 
     An arrangement for the holding of a weft thread for a series shed weaving machine has a holder apparatus ( 11 ) for the weft thread ( 4 ). Two forwarding elements ( 12 ,  13 ) are arranged at both sides of the holder apparatus and are movable relative to the holder apparatus in order to introduce the weft thread. The weft thread ( 4 ) extends transversely to the holder apparatus and transversely to the holder apparatus and transversely to the direction of movement of the forwarding elements, into the holder apparatus ( 11 ) and furthermore, an apparatus ( 14 ) in order to catch and to tension the weft thread. The holder apparatus comprises a thread clamp ( 15 ) with a stationary clamping part ( 17 ) and a movable clamping part ( 18 ) which is under spring action and which forms a clamping gap ( 27 ). The weft thread is held in a stretch state by the forwarding elements ( 12 ,  13 ) and the apparatus ( 14 ) and is displaceable transversely through the clamping gap. The required clamping force can be set in an advantageous manner through the thread clamp. 
     The object of the invention is to improve an arrangement for the holding of a weft thread and to simplify the setting of the clamp. 
     This object is satisfied in accordance with the invention by the characterising features of claim  1 . 
     The advantage that can be achieved with the invention is to be seen in the simplified settability of the clamping force. 
    
    
     In the following the invention will be explained with reference to the drawings. 
     Shown are: 
     FIG. 1 is an embodiment of an arrangement in accordance with the invention in a spatial and pulled apart illustration; 
     FIG. 2 is a section along the plane II—II in FIG. 1; 
     FIG. 3 is a view of the clamping surface and 
     FIG. 4 is a plan view of a part of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a weaving rotor  1  having shed forming elements  2  with means for forming the sheds from warp threads  3  and with an opening for shooting the weft threads  4  through and beat-up elements  5  in order to beat up the weft threads at the cloth edge, a cloth table  6  which cooperates with the beat-up elements, a temple  7  for the cloth and an embodiment of an arrangement  8  for the holding of weft threads  4  which is arranged outside the web width. The arrangement  8  comprises a holder apparatus  11  for the weft thread, two forwarding elements  12 ,  13  in order to introduce the weft thread into the holder apparatus and an apparatus  14  in order to tension the weft thread. The holder apparatus  11  contains a thread clamp  15  and a module  16 . The thread clamp  15  contains a stationary clamping part  17  and a movable clamping part  18 . The stationary clamping part  17  is supported on a cloth table  6  and is connected via a spring  19  to the module  16 . The movable clamping part  18  is arranged at the module  16 . The module  16  is displaceable in the direction of the double arrow A in order to set the position of the component with respect to the weaving rotor  1 , stated more precisely, during a change of web width. With a reduction of the web width the cloth support need not be reduced in length. 
     The module  16  comprises a carrier  21 , a lever  22  which is journalled at one end at the carrier  21  and which is provided with a pin  23  and with a setting member  24  for the movable clamping part  18  and which connects the movable clamping part  18  to the lever  22 , a leaf spring  25  which is fastened at the one end at the carrier  21  and lies at the other end in contact on the pin  23  and a torsion spring  26  which surrounds a section of the setting member  24  and is secured at the one end at the lever  22  and at the other end at the movable clamping part  18 . 
     As FIG. 2 shows the stationary and the movable clamping parts  17 ,  18  form a clamping gap  27 . As already mentioned, the torsion spring  26  is connected to a setting member  24  which is rotatably arranged in the lever  22 . The spring force can be varied with this setting member  24  so that the clamping gap  27  converges more or less. In this way a situation is achieved in which, on the one hand, the clamping force has a lower strength at the entry side and the weft thread is more strongly clamped and as a result is held better with increasing penetration depth. 
     The forwarding elements  12 ,  13  are ring-shaped discs which can be connected to the weaving rotor  1  parallel to and at a spacing from one another in such a manner that the free end of the thread clamp  15  is arranged between the forwarding elements and indeed in the region of the edge part of the weaving rotor. In this edge part the forwarding elements  12  and  13  are in each case formed with cut-outs  31 ,  32  (FIG.  1 ), the number of which corresponds to the number of the weft insertion passages. The cut-out  32  differs from the cut-out  31  in that a hook-like section  33  is present. The latter serves for the pulling out of the weft thread out of the apparatus  14 . 
     As FIG. 3 shows, the clamping surfaces of the thread clamp are provided with grooves  28  which are arranged at an inclination with respect to the path of travel of the weft threads  4  such that weft threads which are introduced into the clamp receive an imparted stretching effect in the insertion direction. 
     Reference is made to FIG. 4, which shows the association of the arrangement  8  with respect to the weaving rotor  1  and the association of the constituents of the arrangement with respect to one another. The apparatus  14  for the catching and tensioning of the weft thread  4  consists of a nozzle  41  with e.g. three outlets and three holder elements  42  and a lamella  43  which consists of a resilient material. The apparatus  14  is arranged in such a manner that the lamella  43  lies in contact under a bias force at the forwarding element  13 . 
     In the following the function of the arrangement will be described with reference to FIGS. 1 and 4, with a weft thread being illustrated in different positions. 
     In the position a the weft thread  4  is subsequently forwarded through the cut-out  31 ,  32  of the forwarding elements  12 ,  13 . 
     In the position b the weft thread has passed the forwarding elements and is held and tensioned by means of the apparatus  14 . 
     In the position c the weft thread is introduced by means of the forwarding elements into the clamping gap of the thread clamp and the weft thread end is drawn out of the nozzle  41  and held between the forwarding element  13  and the lamella  43 . 
     In the position d the weft thread, which is already clamped by the warp threads  3 , is displaced to the cloth table  6 . In this the weft thread is pushed through the clamping gap  27 , with the weft thread being additionally tensioned by means of the inclined grooves in the clamping surfaces. 
     The arrangement comprises a holder apparatus  11  for the weft thread, two forwarding elements  12 ,  13  which are arranged at both sides of the holder apparatus and are movable relative to the holder apparatus in order to introduce the weft thread, which extends transversely to the holder apparatus and transversely to the direction of movement of the forwarding elements, into the holder apparatus  11  and furthermore comprise an apparatus  14  in order to catch and tension the weft thread. The holder apparatus comprises a thread clamp  15  with a stationary clamping part  17  and a movable clamping part  18  which is under spring action, which form a clamping gap  27 , with the weft thread being held in a stretched position by means of the forwarding elements  12 ,  13  and the apparatus  14  and being displaceable transversely thereto through the clamping gap. 
     The required clamping force can be set in an advantageous manner through the thread clamp.