Patent GB-940708-A (GB)
Title: A circular knitting machine for the manufacture of hose with double turned-over tops
IPC: D04B9/54
Filed: 1961-05-09
Abstract: 940,708. Knitting-machines. M. S. MORETTA. May 9, 1961 [May 21, 1960], No. 16773/61. Heading D1C. In a circular knitting machine having needles 3 with alternate long and short butts and sinkers 5 with a supplementary groove 20 forming a second and lower knitting level, the needle and sinker cams are provided with supplementary cams 29, 49, which, in operation, increase the down stroke of the needles and the retracting stroke of the sinkers 5 to form stitches at the level of the supplementary grooves 20 so that, when knitting a double outwardly turned welt, the first two or more rows are knitted at the lower level with both supplementary cams operating after which the supplementary needle cam operates on every alternate needle for one row and thereafter becomes inoperative leaving stitches on these needles at the lower level where they are held until sufficient welt is knitted at the upper level when the held stitches are knitted in to complete the double outwardly turned welt. As shown, needles 3 are held in rotary cylinder 1 by a few turns of spiral spring 4. Sinkers 5, which have butts 23 are mounted on a ring 2 and are biased radially inwards by a spring 6 being controlled by cams in a ring 13 over ring 2. The sinkers, Figs. 8 or 9, have grooves 20, 21 forming lower and upper knitting levels 16 and 17. Alternate needles 3 have long butts and the needle operating cams 27, 29, 30, 31 carried in box 15 can be adjusted to act on all the needles, the needles with long butts or no needles. A drum 12 has raised portions 35, 36 on rings 37, 38 engaged by levers 39, 40 fixed to shafts 41, 42 integral with arms 43, 44 which contact locating pieces on members 45, 46 which carry cams 27, 29. Cams 27, 29 will normally be in the positions to engage all needle butts unless portion 35 causes cam 27 to act only on long-butted needles or portion 36 causes cam 29 to engage the needles with long butts or no needles at all. The extent to which sinkers 5 are moved back by the engagement of the butts with a cam 48 as the needles are lowered may be increased by a cam 49 spring-biased into engagement with the fixed cam 48 and movable to an inoperative position. A cam 50 is movable into position to cause a greater backward movement than cams 48 and 49. In operation, the first course A is formed with cams 26, 27, 29, 30 operative, cam 31 operating on long-butted needles to prevent them from taking the thread, cam 49 operating and cam 50 inoperative. Thus to form stitches at sinker level 16 on every other needle. In the next course B cam 31 is inoperative so that all needles operate to form stitches at level 16. The rows A, B are held on needles 3 by sinker neds 18. Cam 49 is then rendered inoperative cam 29 operating on the long butted needles. In course C yarn is drawn into level 17 of sinkers 5, the needles passing through the stitches of row B. The next course D is knitted with cam 27 fully operative, cam 29 fully inoperative and cam 31 excluding the long butted needles from operation so that the yarn is drawn down and the sinkers pass the yarn of course C behind the needles to connect courses A, B to the rest of the knitting. Normal knitting then proceeds with cam 31 inoperative until sufficient welt is knitted. In a modification, in courses C and D cam 30 operates on only the long-butted needles and the loops on the short butted needles remain in engagement with the yarn of course C. In course D, cam 31 is inoperative and the short-butted needles again take the yarn without casting off while the long-butted needles draw it down. In the following course cam 30 acts on all needles and knitting of the welt proceeds. The welt may be completed either by raising courses A and B to joint the last course of the welt or by lowing the last course of the welt to join courses A and B.