Patent GB-682328-A (GB)
Title: Improvements in and relating to welt turning mechanism in straight bar knitting machines
IPC: D04B11/32
Filed: 1949-08-13
Abstract: 682,328. Knitting. MELLOR, BROMLEY & CO., Ltd., and SHORTLAND, A. Aug. 3, 1950. [Aug. 13, 1949] No. 21117/49. Class 74 (ii). The yarn T of a slack setting-up course is laid with the needles relatively close to the sinker bed 6, and sunk into kinks by jack sinkers or dividers. Every alternate needle is then pressed at an early stage in the descent by an auxiliary presser 14 mounted adjacent to the front edge of the sinker cap 7, and so yields its kink to the sinkers, from which it slides as the sinkers are retracted, into welt hooks 12 which have previously been advanced in a substantially horizontal attitude, into the wide spaces between the sinkers. Each cast-off kink thus extends from each intervening needle to the next over two welt hooks. The intervening needles retain their kinks and draw through them the loops of the second course. A sufficient number of welt courses is now knitted, the welt bar 11 being moved away from the needles and a welt rod inserted, connected to draw-off straps. The welt bar is now moved towards the needles and swung in space, so that the welt hooks, in a downwardly directed attitude pass over the heads of the lowered needles. The hooks are then entered between the sinkers, whilst the jack sinkers 2a are projected, so that the setting-up course needle kinks of the intervening needles are engaged in the throats of the jack sinkers and the cast-off kinks of the alternate needles extend across the top edges of the dividers 2b, which edges are slightly below those of the jack sinkers. The needles now rise to transfix the cast-off kinks, the sinkers are retracted by the catchbar and the welt bar 11 is withdrawn to a rest position under the template rail 81. The hooks 12 are positioned by their insertion between the sinkers so that the penetration of the cast-off kinks by the rising needles is assured. The yarn for the first. course following the welt is laid, the sinkers advance on this and into what were the needle kinks of the setting- up course and upon their subsequent descent, the needles draw loops of the new course through the cast-off kinks of the setting-up course and through the loops of the last welt course. The welt bar 11 is mounted on arms 30 rockable on pivots 31 at the upper ends of L-shaped levers 19 connected by pin and slot connection 29 with truck levers 20 pivoted at 21 and having opposed shoggable trucks 22, 23 engaging a cam 24 and counter-cam 25 on the main cam shaft 10. As the front ends of truck levers 20 rise, the operating levers 19 can pivot about a locating shaft 28, so that their upper ends move towards the needle line, until the upper ends of slots 26, rest on shaft 10 : the levers can then pivot about shaft 10, slots 27 rising from shaft 28. Thus the hooks 12 remain in a substantially horizontal attitude in that part of their traverse in which they are adjacent to the needle line at the beginning of the welt. In order to move the welt hooks from their horizontal attitude to their downwardly directed attitude and vice-versa, the levers 30 are rocked by a crank or cranks 36, also pivoted on the levers 19 and having slider and slot connection 34, 33 with at least one of levers 30. The crank 36 is rotated by two co-axial star wheels, of which one 38 is fast on shaft 37 of crank 36 and the other, 38b is loose thereon and is rotatable anti-clockwise relatively to star wheel 38a through an angle of at least 60 degrees, determined by a pin 39 on shaft 37 and arcuate slot 40 in wheel 38b. As the operating levers 19 swing towards the needles to take the welt bar from its rest position, the slider 34 is approximately midway along slot 33 and a tooth 47 on wheel 38b clicks idly past four fixed pins 42-45, the hooks 12 thus remaining horizontal. As the levers swing back, the crank 36 is turned clockwise through 240 degrees by engagement of teeth 47, 48, 49, 50, each with one of the four pins : the arms 30 are thus swung upwardly to their extreme positions. At the next advance of the welt bar a tooth 51. on the loose wheel 38b clicks idly past the pins 42, 43 and, being relatively thin, misses pins 44, 45 which are relatively short. When the levers finally swing away from the needle line after completion of the welt, the thin tooth 51 misses short pins 45, 44, but the crank is then turned through 120 degrees by pins 43, 42 bringing the arms 32 into their original position relative to the levers 19. A welt stick is placed, by hand or otherwise, in grooves 54 in guides 53 to rest on the fabric. Its ends are engaged by hooks 55 on straps 18 drawn from a roller 56 by a take-up roller 57.