Patent GB-226647-A (GB)
Title: Improvements in or relating to yarn changing means for circular knitting machines
IPC: D04B9/10
Filed: 1923-11-03
Abstract: 226,647. Spiers, W. Nov. 3, 1923. Circular machines.-Relates to yarn-changing mechanism, for producing horizontal stripes, of the kind comprising a number of yarn carriers adapted for rotation, bodily and intermittently, by automatic pattern-controlled mechanism, to bring the different carriers into register with a common feeder. According to the present invention the yarn is engaged by a special sinker, inserted in the usual sinker ring but actuated by a separate cam track, which draws the yarn into the needles. Yarn trapping and severing means are also provided and the device is rotated in two stages. The device is shown applied to a super-imposed cylinder machine and comprises a rotatable vertical shaft 4 provided with a flange or dial 32 having grooves 33 in which the yarn carriers 34 are slidably arranged with springs 36 behind them, an upwardly extending butt 35 on each carrier engaging a fixed ring 38 which is recessed on its inner periphery to allow the carrier 34 to move outwardly when opposite the common feeder 1. The lower end of the shaft 4 is provided with a pawl and ratchet mechanism 63 actuated by a two step cam 58 on the bevel wheel which drives the lower cylinder 20, the arrangement being such that each advance rotary movement of the shaft and yarn carriers takes place in two stages with a pause between. Pattern mechanism is provided to put the pawl and ratchet mechanism into action. A collar 42, secured on the shaft 4 below the dial 32, is provided with a series of radial members 44 provided with shearing edges, a trapper 44, also provided with a shearing edge, being associated with each member 43 and arranged to slide vertically in the collar 42, a downwardly extending leg 45 on each trapper riding, on a fixed cam 47. Pivotally mounted on the ring 38 is a spring controlled finger 50 having a foot 50<a> engaged by the butts 35 so as to raise the finger which is shaped at its end to engage with the yarn. A sinker 67, having a finger 67<a> to engage the yarn, is provided in place of an ordinary sinker and independently actuated by a cam track 69 below the ordinary sinker cam track 70. An upper vertical shaft 4<a> is yieldingly coupled to the shaft 4 by springs 24, a bobbin carrier 9 being secured to the shaft 4<a>, and each of the yarns 28 is conducted upwards and then downwards through guides 29, 30, 31 to the yarn carriers 34. A ring 12 secured to the top of the shaft 4 is provided with double gaps 13, 14 engaged by a spring controlled plunger 15 actuated, through the medium of a lever 17, by two cams 18 attached to the upper needle cylinder 20. When a yarn change is about to take place, the plunger 15 is moved out of engagement with the ring 12 and the shaft 4 partially rotated so that the yarn carrier 34 supplying the yarn is partially withdrawn and the following carrier 34 brought round towards the feeder 1 thereby putting a length of yarn between its end and the corresponding trapper and allowing the pivoted finger 50 to fall and draw the yarn down. The leg 45 of the trapper associated with the yarn carrier 34 going out of action rides up the cam 47, thereby opening the trapper, the yarn passing between the members 43, 44. During the pause in the rotary movement, the finger 67<a> engages the yarn drawn down by the finger 50 and draws it to the needles through a slot 3 in the common feeder 1, the needles knitting with both the old and new yarns until the second stage of the rotary motion occurs, whereupon the old yarn is severed and trapped. In order to facilitate the entrance of the yarn into the slot 3, the outer ends of the carriers 34 engage and ride on a cam surface 74 formed beneath the slot. The device is locked after each stage of the rotary movement by the plunger 15. A suitable brake may be provided to engage frictionally the locking ring 12 for steadying the rotary movement.