GB625894A - Improvements relating to thread controlling apparatus in textile machines - Google Patents

Abstract

625,894. Knitting-machines; lace machines. F.N.F., Ltd., MORRISON, J. L. M., WOODWARD, R. T. C., PEEL, R., and GREAVES, E. Feb. 12, 1946, No. 4381. [Classes 74 (i) and 74 (ii)] [Also in Groups IX, XXIV and XXXV] The speeds of rotation of the beams of a warp knitting-machine or of a lace machine are adjusted during operation of the machine to counteract the decrease in the effective diameter of the mass of the warps on the beams, in order to maintain the feeding of the warps at a constant rate. As described, two warp beams 4, 7 for a warp knitting-machine are driven through shafts 8, 9, connected to gearing housed in a gear-box 11. A bobbin 13 or 14 is provided for each beam to supply a thread which passes round its respective beamed warp and then to the needles to be taken in the normal manner, the bobbin thread being delivered at the same speed as the warp. Between each beam and its bobbin, the yarn engages a pulley 18 or 19, which is freely rotated as the yarn is withdrawn. A bracket 42 is mounted on each of the shafts 23 supporting the pulleys and carries electrical contact brushes 40 which are held in contact with discs 30, 31, provided with electrical contact segments. The discs 30, 31 are driven from the main shaft at a constant speed equivalent to the desired rate of delivery of the warp threads and rotate synchronously with the pulleys. As the warps are fed from the beams, the effective diameter of the warps on the beams decreases and the rate of delivery of the warps becomes less. Consequently, the pulley tends to lag behind the disc and relative movement takes place causing the brushes to make contact with the segments, thereby completing an electrical circuit to operate a clutch and effect an increase in the speed of rotation of the beam. Relative movement in either direction is counteracted by the brushes engaging segments on the discs and effecting a decrease or increase in the rotation of the beams. The varying of the rotation of the beams is achieved through cone and ring contact, the ring being moved along the cone to alter the speed. Indexing means, associated with the control moving the ring, indicates the ratio of the drives. Alternatively, photo-electric cells co-operating with apertures formed in the pulleys and discs may effect the variation of the speeds of the beams or the disc and pulley may constitute part of a differential gearing, a third gear meshing with both and effecting the variation. Specification 548,496 is referred to.