This invention relates to a method for disposal of defective weft yarn in a fluid jet loom.
In general, in a fluid jet loom, the weft yarn is impelled into the warp shed by pressurized fluid such as water or air supplied under pressure from a weft yarn inserting nozzle. In this type of loom, since the weft yarn is impelled only from one side of the loom frame, the weft yarn must be cut at a connecting portion from the selvedge towards the yarn supply each time a measured length of the weft yarn is impelled into the shed.
Referring to FIG. 1, there is shown a conventional loom, wherein the weft yarn W is supplied from a weft yarn supply source 31 to a conventional length measurement unit 33 through a tensioner 32, and the weft yarn W whose length has been measured is supplied by way of an air nozzle 34 for weft yarn pooling, a weft yarn pool pipe 35, weft yarn guide 36 and a gripper 37 to a weft inserting nozzle 3 mounted along with a reed 2 on the upper surface of a sley 1 which is adapted for performing a swinging movement in a known manner. Pressurized fluid is injected along with the weft yarn W in the direction of a guide passage defined by a row of guide members 4 provided at a predetermined pitch at the side of the reed 2 towards the cloth fell. A weft yarn cutter 5 is mounted in the vicinity of the cloth fell on the weft inserting nozzle side for operation in time with loom operation. A cutter blade 7 is provided on the side opposite to the cutter 5 for cutting the waste selvedge 6. A weft yarn sensor 8, which may be of a conventional, photoelectrical type, is provided on the sley 1 on the side opposite to the nozzle 3 for detecting a defective weft insertion. Upon occurrence of a defective weft yarn insertion, it is sensed by the sensor, and the loom operation is discontinued. The defective weft yarn is removed in this state and the loom operation is again started.
In this conventional fluid jet loom, since the loom is operating at a higher r.p.m., it is not possible to stop the loom immediately because of the required braking time even if the occurrence of the defective weft yarn insertion has been sensed by the sensor. It is only possible to stop the loom operation after the defective yarn is beaten up against the previously inserted weft yarn, the weft yarn is cut on the side of the nozzle 3, and the next length of the weft yarn is inserted into the shed. Therefore, disposal of the defective weft yarn may be effected only by extracting the weft yarn which was inserted after the insertion of the defective weft, then, driving the loom frame in forward or reverse direction either by manual operation or actuation of an inching push button, and then opening the upper and lower warp yarns for removal of the defective weft yarn.
However, since the defective weft yarn has been previously cut in the vicinity of the selvedge by the cutter 5 and only a small portion of the yarn is exposed outside of the selvedge and, moreover, the defective weft yarn has undergone the beating to form a part of the cloth, it is extremely difficult to detach it from the cloth. Thus, the conventional practice is to pull out several points of the defective weft yarn into the warp shed using a taper needle, and to pull the weft yarn out of the row of warp yarns by a labor-consuming and painstaking operation.
Therefore, demand has arisen for a method for disposal of defective weft yarn in a fluid jet loom which is free from the above inconveniences of the prior art.