GB676790A - Improvements in or relating to straight bar knitting machines - Google Patents

Abstract

676,790. Knitting-machines. WILDT & CO., Ltd., BARSBY, E. S., and SAUNDERS, A. P. Aug. 18, 1950 [Sept. 5, 1949], No. 22948/49. Class 74 (ii). The racking screw 6 for moving the narrowing points 11 of a straight-bar machine has limiting mechanism associated with it to limit its movement and to prevent over-racking of the points in the event of incorrect timing. The limiting mechanism which only operates upon excess movement of the racking screw comprises a finely screw-threaded sleeve 76 rigidly secured to a bracket 21, carrying part of the narrowing mechanism, the sleeve 76 having a correspondingly internally-threaded nut 77 mounted on it which is engaged by an arm 80 attached to a driving shaft 19 geared to the screw 6 so that the nut is rotated with the racking screw. Ratchet-wheels secured to the shaft 19 are actuated by pawls to rotate the shaft. The nut 77 has lugs 78, 79, one of which, in the point of over racking of the screw 6, engages, towards one end of the traverse of the nut, an arm 86 so as to pivot the block 84 in which it is mounted and to cause a second arm 83 in the block to engage a pin 85 extending from a projection 25b of one of the pawls 25 operating the ratchet-wheels, thereby rendering the pawl inoperative and preventing further movement of the racking screw. Similarly, the other lug engages an arm 89 in a pivoted block 88 carrying a second arm 87 adapted to contact a pin 90 in a projection 26b of a second ratchet 26 for rotating the screw 6 in the opposite direction and to render it inoperative upon excessive movement of the racking screw in this direction.