Patent GB-946955-A (GB)
Title: Improvements in stitch length control for circular knitting machines
IPC: D04B9/02
Filed: 1961-07-03
Abstract: 946,955. Knitting-machines. TEXTILE MACHINE WORKS. July 3, 1961 [July 15, 1960], No.23987/61. Heading D1C. In a multi-feed circular knitting machine having a plurality of knitting stations and a plurality of cam assemblies adjustable between raised and lowered positions to vary the lengths of stitches formed at the said stations, a common control element is provided for simultaneously adjusting the cam assemblies, further means under pattern control operating the control element during knitting. The machine, which may be that disclosed in Specification 790, 141 (Group VIII) comprises a needle cylinder 15 having four feeding stations associated with cam assemblies 16 which include cams 18 displaceable vertically, to adjust the stitch length, by the rotation of a ring 57 disposed around the periphery of a table 40 and engaging shafts 45 to rotate the latter and adjust the positions of the respective cam 18. The ring is moved by linkage engaging, at different times, a left pattern drum 102 or a ring 110 surrounding that drum and driven either by the drum or by a ratchet and pawl device. Each cam assembly (see Fig. 4) comprises cams 18, 22 secured to a block 26 slidable vertically in a bracket 36 and provided with a transverse slot engaged by an eccentric portion at one end of the shaft 45. The other end carries a member 46 which is rotatably adjustable on the shaft by a worm and worm-wheel device. The member 46 carries an adjustable stop abutting a corresponding lug on the ring 57; rotation of the ring thus rotates the shafts 45 of the cam assemblies to raise or lower the cams. A projection 67 on the ring (see Fig. 2) carries a lever 77 connected by a link 80 to one arm 81 of a bell crank lever, the other arm of which carries (see Fig. 10) four adjustable cam followers 91 and a roller follower 107. The four followers 91 are adapted to engage rows of cam lugs 101 on the left pattern drum 102 and, except as described below, one or the other of these followers is always in contact with its associated row to control the length of stitches formed in the stocking fabric. The roller 107 is adapted to ride on a cam ring 110 rotatably mounted on the drum 102 and engaging a braking device 116. Ratchet teeth 121 on the periphery of the cam ring are engagable by a spring biased pawl 122 carried on one arm of a lever 125 rockable by a roller 130 eccentrically disposed on a shaft 132 which rotates at one quarter of the needle cylinder speed. The cam ring carries pawl blanking cam lugs 133, 135 (see Fig. 2) which there render the pawl ineffective. The lever 125 is also rockable by a link 137 connected to one arm of a lever 138 the other arm of which has a rose 141 engageable by one or more cam lugs 142 on a right pattern cylinder 105. Operation. At the start of a stocking knitting cycle the drum 102 and ring member are in the position shown in Fig. 2, when a follower 91 engages its cam lug 101. The cam ring has a low portion 120 opposite the roller 107 and the pawl is disengaged from the teeth 121 by the cam lug 133. As knitting proceeds the drum 102 is indexed relatively to the cam ring until a plate 148 on the former engages a pin 150 on the ring, the latter then moving with the drum to remove the lug 133 from beneath the pawl which then operates to index the ring 110 and gradually decrease the length of the stitches from calf to ankle as roller 107 rides up the rise portion 117 of the ring. As the end of the concentric portion 118 of the ring approaches the roller the cam lug 135 disengages the pawl and the ring stops. At the start of the heel a cam lug 142 of drum 105 rocks lever 138, 141 to move the pawl beyond the lug 135 and advance the ring to its starting position with the low portion 120 again opposite the roller 107, the lugs 101 on the pattern drum 102 then co-operate with followers 91 to control the length of the stitches in the heel of the stocking.