GB764694A - Improvements in or relating to automatic stitch length control mechanism for circular knitting machines - Google Patents

Abstract

764,694. Knitting-machines. WILKES HOSIERY MILLS CO. Jan. 13, 1954 [Jan. 23, 1953], No. 985/54. Class 74 (2). To maintain evenness of loop structure of a stocking knitted on a circular machine and also to enable the loop size to be varied for fashioning purposes, a pivoted plate 84 mounted in the sinker cam ring 36 is engaged by the sinkers and, depending on the tightness of the loops, moves inwardly or outwardly to influence a detector switch 75. The detector switch is in the circuit of an electric motor which when energized raises or lowers the needle cylinder in relation to the knitting cams to effect an alteration in loop length. By adjusting the position of the switch in relation to the plate 84, the loop length is gradually decreased for fashioning the leg of a stocking. The switch 75 comprises a pivoted arm 82 having a finger 83 held in engagement with the plate 84 by a spring 90 and thereby urges the plate into engagement with the rear end of the sinkers. The end of the arm 82 lies between two contacts 91, 92 which through limit switches control the electric motor 70. Any variation in the position of the plate 84 due to the sinkers moving in too far against the loops or not far enough, causes the arm 82 to contact either of the contacts 91, 92, thereby operating the motor. The motor 70 drives a worm gear 71 connected through a screw 72 to the fabric take-up tube 40 so as to raise or lower the needle cylinder 15 supported at the top of the tube 40. For fashioning purposes, the switch 75 and arm 82 are gradually withdrawn from the sinker ring so that one of the contacts is engaged, causing the motor to lower the needle cylinder, whereby smaller loops will be produced whilst the sinkers engaging the loops press the plate 84 outwardly until the switch 75 is broken. Withdrawal of the switch 75 is achieved by mounting it on a plate 76 which is engaged by a wedge 96 operated through a cable from cams 118, 119, 120 on the shaft of the cam drum. These cams are brought into operation by pawl-and-ratchet mechanism 122, 130 operated from the quadrant gear.