Patent GB-968001-A (GB)
Title: Improved draw-down mechanism for a flat knitting machine
IPC: D04B15/90
Filed: 1961-12-11
Abstract: 968,001. Knitting machines. H. STOLL, G. STOLL, E. STOLL, E. STOLL, J. STOLL, A. STOLL, R. E. STOLL and M. STOLL, [trading as H. STOLL & CO.]. Dec. 11, 1961 [Dec. 12, 1960], No. 44172/61. Heading D1C. A double bed flat knitting machine comprises a fabric draw down mechanism and includes hooks 2 operated by a cam and gearing which are raised when the fabric is widened so that the marginal hooks engage the last knitted loops of a separating thread at the margins of the fabric and the other hooks extend higher to engage the newly formed loops of a non-run course after which the hooks are lowered below the intersection of the needles and then intermittently until the widened fabric has been introduced between an intermittently driven roller 6 and guide means 9. As shown, the hooks 2 are adjustably mounted on a bar 1 displaceably mounted on guide bolts 3 and connected to two toothed racks 5 by which it is adjusted heightwise. The draw down roller 6, which may consist of a solid roller or a plurality of parts secured to a shaft 7, has a resilient covering 8, e.g. of bristles. Roller 6 is partly enclosed by a casing 9, Fig. 3, mounted in a support 10 to form a draw down channel 11, which may be narrower at its entrance, 11<SP>1</SP>, and into which the knitted web G is drawn by the hooks 2 as they move through vertical grooves 12 in casing 9. In modifications, roller 6 may have a rigid surface and casing 9 may be resilient, or resilient bands may be provided on roller 6 with a rigid surface or both roller 6 and casing 9 may be resilient. The support 10 and casing 9 is mounted on compression springs 15 supported on sleeves 14 adjustable in frames 13. V-blocks 17, Fig. 4 bear against the ends of shaft 7 and have bolts 16 extending through the sleeves 14 of frames 13 which are pivoted to levers 19, one of which forms one arm of a rocking lever 22 so that casing 9 may be swung manually into and out of its operative position. A cam 27 on a driven shaft 26 oscillates on member 24 carrying a pawl 25 which engages a ratchet wheel 23 to drive it intermittently. A draw-down weight 29, Fig. 1, is suspended by a carrier 30 from a chain 31 carried on chain wheels 33, 34, 35 mounted in a casing 32, wheel 35 and housing 32 being pivotable to vary the draw-down force. A toothed wheel 39, Fig. 4, on shaft 7 is connected through gear-wheels 40, 43 with a toothed wheel 44 freely rotatable on the main drive shaft 45 which also carries a pinion 46 for displacing racks 5. Wheel 44 is connected by pins 47 to wheel 23 so that it and hence shaft 7 is rotated intermittently. A clutch disc 49 is connected by pin 48 to wheel 44 so that it is also rotated intermittently. A second clutch disc 50 is axially displaceable along spindle 45 under the control of the patterning device. The gearing is such that the peripheral speed of roller 6 is equal to that of the pitch circle of pinion 46. A pinion 56 secured to shaft 26 adjacent cam 27 meshes with a toothed gear 57 freely rotatable on shaft 45 and connected by a pin 58 to a driving ring 59 with driving recesses 60. A longitudinally displaceable toothed bar 61, see also Fig. 5, is engaged by a pinion 63 secured on a spindle 65 together with a toothed wheel 64 which is engaged by a toothed wheel 66 fastened on shaft 45. A roller 62 on bar 61 engages a cam groove 38<SP>1</SP> in a disc 38. Thus movements of bar 61 are transmitted to pinion 46 and rack 5. Secured to cam disc 38 is a housing 67 containing a driving bolt 68 biased against driving ring 59. An actuator operated by the patterning device is attached to one arm of a bell crank lever 71, 72 so that bolt 68 can be projected into one of the recesses 60 in driving ring 59. In operation, with the hooks 2 as shown in Fig. 1, bolt 68 is allowed to engage in recess 60 in ring 59 so that cam disc 38 is rotated by shaft 26 through wheels 56, 57. The roller 62 on toothed bar 61 is at point X, Fig. 5, and before the cam carriage commences a stroke roller 62 moves to point Y so that bar 1 is moved down and the lower hooks 2 engage the separating thread at the widened edges. During the next stroke of the machine roller 62 moves from Y to Y<SP>1</SP> and bar 61 does not move as groove 38<SP>1</SP> remains on an arc whose centre is shaft 45. During the reversal of the carriage at the end of the stroke roller 62 moves to point Z so that the remaining hooks 2 engage the non-run course just knitted. Bolt 68 is then released and clutch 49, 50 is engaged to enable ratchet wheel 23, and hence racks 5 and hooks 2, to be driven intermittently from cam 27.