GB1108735A - Method and apparatus for preventing weft gap formation on resumption of weaving on a travelling wave shedding loom after loom stoppage due to a weft defect - Google Patents

Abstract

1,108,735. Travelling-wave shedding looms. OERLIKON-BUHRLE HOLDING A.G. 14 April. 1965 [14 April, 1964], No. 16114/65. Heading D1E. A travelling-wave shedding loom, wherein a plurality of shuttles lay weft in successive sheds formed from continuously let-off warp threads, has means to prevent the triangular weftless gap that occurs in the fabric, because of the continuous let-off, upon resumption of weaving after removing a defective, subsequently laid and partly laid wefts. In Fig. 1 with shuttles 21 entering the sheds from the left side of the loom and laying the wefts along the fell 18, rollers 15, 26, pivoted at 29 on the right side of the loom, bear upon the warp and fabric respectively and have their left hand ends located in arcuate slots 31, 32 and are linked to a pivoted beam 38 so that roller 26 is normally down and deflects the fabric progressively across the loom from right to left and the roller 15 is normally up and does not deflect the warp. If, upon weft fault and loom stoppage, four wefts are removed a triangular gap would be left at the fell 18, the gap having no width at the right of the loom and increasing in width to the left. This gap is then removed by pivoting the lever 38 causing the roller 26 to rise and the roller 15 to correspondingly fall. The pivoting of the beam 38 is caused by a cam 55. Without resuming let-off the shuttles are picked and simultaneously the beam 38 is pivoted causing the roller 26 to fall and roller 15 to rise so that the shuttles lay weft in the reforming triangular gap. When the first shuttle reaches the far side of the shed during one revolution of the cam 55 the roller 26 is again fully lowered and normal weaving recommences. Various ratios of tilt may he given to the beam 38 to cause differential pivoting of the rollers 15, 26 to compensate for varying weft densities. In Fig. 6 the back rest 70 and breast beam 71 are pivoted at the left of the loom. and are movable in the warpwise direction on the right of the loom by a lever 87 operated on by a cam 93 in a similar arrangement to that of Fig. 1. Upon removing defected wefts the right hand ends of the back rest 70 and breast beam 71 are moved forwardly so that the triangular gap becomes rectangular and is spaced from the beat-up line 18. The warp is then taken up until the fell coincides and is parallel with the line 18. Normal weaving is then resumed and at the same time the back rest and breast beam are progressively returned rearwardlv to the Fig. 6 position so that the laid and partly laid weft fill the reforming triangular gap. A third embodiment Fig. 7, has one pivoted roller 26, similar to the embodiment of Fig. 1 and a bight roller 123 that acts on the warp by gravity and is capable of tilting to take-up the deflection caused by pivoting of the roller 26. In Figs. 1 and 6 the shuttles are moved and the wefts beaten-up by cam operated combs 21. In a fourth embodiment Figs. 8 and 9, the shuttles 21 are moved by slides 130 actuated by cam operated rods 133 on which are pivoted beat up combs 131 whose lower ends 141 are pivoted on-slides 143 which are movable in the warp direction by a lever 148 pivoted at 149 so that their beat-up positions at the fell are progressively variable to take up the triangular gap caused by weft removal. The combs are moved during resumption of weaving, as the triangular gap that reforms is filled by weft, so that, in this embodiment, it is the beat-up line, and not the warp threads, that is progressively moved across the fabric