Improved yarn feeding and changing mechanism for circular knitting machines

摘要

821,151. Knitting-machines. WILDT & CO. Ltd. Sept. 1957 [Oct. 15, 1956], No. 31292/56. Class 74(2). Yarn feeding and changing mechanism is provided at a feeder of a circular cylinder and dial machine to enable striping effects to be produced by changing one yarn guide for another when desired and as controlled by a pattern chain associated with the mechanism. A number of yarn guides 53 are pivotally mounted side-by-side in a unit 20. Associated with each guide 53 is a yarn placer 46 which is also pivotally mounted in the unit and which has a channel formation 48 at its lower end adapted to engage the guide 53 and its yarn. The placer has a member 49 rigidly secured to its upper end and which member has a protuberant portion 50 adapted to be engaged by a slide 29. A spring 56 couples the placer and yarn guide. The slide 29 is normally retained in a withdrawn position by a spring 31 but on being advanced it engages the portion 50 to pivot the placer such that the bottom of the formation 48 engages the yarn guide and initially raises it to a position above the dial needles whereafter the end of the guide is engaged in the channel portion 48 as the placer moves above the dial needles to extend the yarn to a position in which it can be taken by the dial needles. For this purpose the end of the yarn is held whilst the guide is in its inoperative position by a clamping and severing device U which comprises a slotted block 57 provided with pivoted cutter and clamping- blades 60, 59. These two blades are coupled together and also to a lever 44 which projects upwardly to engage in a slot 42 in the slide 29. The effect of this is that after the guide and placer have been advanced, the slide 29 continues to move forward, riding over the portion 50 without causing further movement of the placer and until the shoulder 43 of the slot 42 engages the upper arm 72 of the lever 44 whereupon the cutter and clamping blades are opened to release the end of the yarn. This release, of course, occurs after the yarn has been taken by the first few dial needles. A clamping and severing device is associated with each yarn guide and its associated placer. The slide is held in its advanced position by a pawl 36 engaging notches 34, 35 in the top edge of the slide. The two notches correspond to the movement of the slide necessary to (a) advance the guide and placer, and (b) to release the trapped yarn. The device U is held with its blades open by a catch 74 which engages behind the projection 75 on the lever 44 after the lever has been operated by the slide 29. Selection is achieved by providing a butt 33 on the slide 29 and each slide has a butt at a different height so that by mixing or lowering a selector 41 at the dictates of a pattern chain 18 one or other of the slides and the corresponding guide can be selected as the parts relatively rotate. Simultaneously with the raising of the selector 41 from a low neutral position, striker cams 82, 83 are also raised, which engage plungers 39, 78 as they relatively rotate, causing them to trip pawls 36 and catches 74 which thereby release the guide being returned to inactivity and enable the yarn to be clamped and severed. The blades 59, 60 are closed automatically, when the catch 74 is released, by a spring 70.