Patent GB-651833-A (GB)
Title: Improvements in or relating to pattern mechanism for knitting machines
IPC: D04B9/26
Filed: 1947-02-14
Abstract: 651,833. Knitting-machines. SCOTT & WILLIAMS, Inc. Feb. 14, 1947, No. 4357. Convention date, Feb. 21, 1946. [Class 74 (ii)] Controlling mechanism, in combination with a knitting-machine, comprises primary and secondary controlling devices and cyclically operating means for advancing the primary controlling device, said means having in each cycle of its operation a forward movement between its extreme positions comprising a plurality of forward steps with an interruption of continuity of movement between the steps, followed by a return movement between its extreme positions, advance of the last mentioned controlling device occurring during said steps, no useful reverse movement being imparted to the advancing means between the steps. A pattern chain 70 constitutes the primary controlling device and a cam-carrying drum 54 the secondary device. The chain and drum are advanced by pawls 93, 48, the stroke of each pawl being a series of steps without any reversal of movement therebetween. The movements are imparted to the pawls by cams on a shaft which rotates at halfcylinder speed. Lugs 68 on the pattern chain control the racking of the drum by rocking a lever so as to lower the end 60 thereof to permit the pawl 48 to engage its ratchet. The nose of the pawl 93 is wide enough to cover both the chain-drivng ratchet 96 and a masking ratchet 98 which is of greater diameter than ratchet 96 ; the masking ratchet will thus be stepped round and the driving ratchet will remain stationary unless or until a low part 102 on the masking ratchet comes under the pawl. The ratchet 98 will then stop and the chaindriving ratchet 96 will be racked round to advance the chain until one of a number of lugs 106 thereon is brought into contact with the rear of a block 104 on ratchet 98. The next stroke of pawl 93 will again advance the chain, but will simultaneously carry the low space 102 beyond the field of action of the pawl. Subsequent strokes of the pawl 93 will therefore advance only the masking ratchet 98 until the block 104 thereon is brought behind lug 106, to carry the chain forward on the next stroke, which also brings the low part 102 again under the ratchet. Thereupon, the ratchet 96 will again be racked round until another lug 106 engages the block 104. The masking ratchet can thus be used to count the courses in those parts where the chain would otherwise have blank links. The chain is advanced the length of one link in two steps, in the time corresponding to two rotations, or a forward and backward reciprocation, of the needle cylinder whilst at the same time, the drum pawl makes one stroke made up of an initial advance followed by successive short advances. The advances of the pawl 93, indicated at 176, 180, end before the beginning of the advances 118, 126 of the pawl 48. Thus, at the ends of the advances 176, 180 and before the advances of the drum pawl 48, the lever end 60 is positioned to determine whether or not the pawl 48 shall engage the drum ratchet, and the chain and drum cannot get out of step. A pivoted, spring-urged lever 101 carries locating detent 107, 109 engageable in the notches between the teeth of masking ratchet 98 and spaced to straddle the low part 102. Specification 617,148 is referred to.