Patent GB-535946-A (GB)
Title: Improvements in or relating to yarn-changing mechanisms for knitting machines
IPC: D04B15/60
Filed: 1939-10-25
Abstract: 535,946. Knitting-machines. BENTLEY ENGINEERING CO., Ltd., MANGER, C. F., and WAINWRIGHT, C. H. Oct. 25, 1939, No. 28702. [Class 74 (ii)] In yarn feeding mechanism of the kind comprising yarn feeders 22 arranged at different heights and actuated so that the yarn feeding ends of the feeders have a movement towards and away from the needle bed, together with a movement lengthways of the needles, an outgoing feeder end is first displaced from its normal feeding position 21 to another position at which it will still continue to feed yarn to the needles after the ingoing feeder end has been moved to feeding position. The ingoing feeder end is moved from its idle position to a temporary position other than its normal feeding position but in which it can introduce its yarn to the needles, so that the outgoing feeder can return to idle position along a path that is clear of the temporary position of the ingoing feeder. The yarn feeders 22 are rotatably mounted upon a vertical shaft 23, and are moved into and out of feeding position by levers 27, each of which levers is actuated by a cam 33 independently rotated by its own ratchet wheel 35. Engagement of a lever 27 with a high tooth of a cam 33 corresponds with the inoperative or rest position of the corresponding feeder ; with the lever 27 on a low tooth, the feeder is in feeding position 21. The provision of spaces between the low and high teeth permits a feeder to move into its second feeding position. The ratchet wheels 35 are rotated by pawls 86 under control of one of two continuously rotating cams (not shown), and selection of the ratchet wheel 35 for rotation of its cam 33 is made by a vertically movable selector bar 88 having a notched edge. The bar 88 is moved under pattern control so that one of its notches 87 is brought into alignment with a pawl 86 so that that pawl is free to actuate its ratchet wheel; the remaining pawls 86 are restrained by the solid edge of the bar so that they are held away from their respective ratchet wheels. To obtain the vertical movement of the feeder ends, a cranked tail portion of each feeder is secured to an arm 29, each arm 29 engaging in a cam slot in a guide plate 30, so that as the feeder is rotated by its lever 27, its feeding end is moved lengthways of the needles. Trappers 41 ... 43, one to each yarn feeder 22, are provided and are actuated by cams 91, also secured to the ratchet wheels 35. To enable the length of the free end of the ingoing yarn to be kept substantially constant, the trappers are moved bodily about an axis 59 so that the trapper for an ingoing yarn will always take up the position of the trapper 41 shown in Fig. 1. The movement of the trappers about the axis 59 is obtained from a cam 93 also mounted on the post 34, upon which the cams 33 and wheels 35 are mounted, and the amount of the movement is determined by a stepped stop plate 60 under control of a pattern chain (not shown). By providing two continuously rotating cams for actuating the pawls 86, one cam having a single lobe and the other having two lobes, change of yarn can be obtained either once in each revolution, for example, in the leg of a stocking, or twice in each revolution, as in the foot of a stocking having a patterned instep and a plain foot bottom. Specification 470,020 is referred to.