Patent GB-907570-A (GB)
Title: Cam control for knitting machines
IPC: D04B15/66
Filed: 1959-05-21
Abstract: 907,570. Knitting-machines. HOFFMANN, K. May 21, 1959 [May 28, 1958], No. 17300/59. Class 74 (2). A supporting member, for at least one setting element to control the step-by-step movement of a main pattern control member, forms a single element with the said main control member; and the setting element is adapted selectively to stop the step-by-step movement of the said members for preselected operating cycles. A main control drum 1 has a part 1<SP>1</SP> in holes 8 in which pins such as 9a can be inserted to stop the racking of the drum by a pawl 3. When a pin 9a comes under the toe 10<SP>1</SP>a of a bell-crank lever 10a, 11a, that lever will be rocked against the action of a spring. The toe 10<SP>1</SP>a will thereby push down a link 15a, against the action of a spring, to depress a lever 16a pivoted at 17 and so, through a link 20, disable the pawl. At the same time, the other end 11<SP>1</SP>a of the bell-crank lever will release a nose 21<SP>1</SP>a of an arm 21a, which will be pulled down by a spring until its lower end 21<SP>11</SP>a rests on the periphery of a cam wheel 22a. A cam 24a on the arm 21a will, at the same time, move out of the path of a locking- bar 19a, allowing the bar to rotate about a pivot 18a (under the action of a spring) into position over a detent 17<SP>1</SP>a on the link 15a, to hold the link down, despite removal of pin 9a from under toe 10<SP>1</SP>a by the last movement of the drum 1 . Simultaneously, the nose of a pawl 26a, hitherto disabled by a pin 25a on the arm 21a, will be allowed to drop into engagement with a ratchet 27a fast with the cam-wheel 22a. This pawl is, with others of a set, pivoted on a member 28 continually rocked about a shaft 30 by a cam 32 rotating in time with a cam which operates the pawl 3. The pawl-and-ratchet 26a, 27a will now rotate the cam-wheel 22a until a cam 23 thereon raises the arm 21a, the nose 21<SP>1</SP>a of which will again snap over the nose 11<SP>1</SP>a of the bell-crank. As the arm 21a rises, its pin 25a will again disable the pawl 26a and its cam 24a will bring the locking lever 19a from over the detent 17<SP>1</SP>a, allowing all the members of the linkage to return to their initial positions and the pawl 3 to become operative again. Associated with each of a row 8a-8g of pins is a similar linkage. Recesses 33a-33g in the levers 16a-16g, allowing the pawls 26a-26g to rock into active position, are of decreasing length, so that summation of the effects of all pins present in a row is obtained; and since the cam-wheels 22a- 22g bear, respectively, 1, 2, 4 ... 64 cams, the number of revolutions of cam 32 between disabling and reactivation of pawl 3 is variable within wide limits. The control cylinder 1, 1<SP>1</SP> may be replaced by a card 101, Fig. 10, bearing two sets of holes, one set 109a. . . of which controls the mechanism of the machine whilst the other set controls movement of the card. The card is stepped along periodically the distance between adjacent rows of holes and is then moved perpendicularly to its plane, towards pins 108a . . . . Any pin not finding a hole will rotate a bell-crank 110a, 111a . . . analogous of the bell-crank 10a, 11a, &c. In Fig. 12, the drum racking pawl 203 is effective so long as solenoid 203<SP>1</SP> is energized from a source 250 of current. When any pin 209 closes a corresponding switch 210a, say, of a series 210a-210g, a related solenoid 215a . . . is energized to move the arm of a switch 216a . . . from a first position against a contact 252a . . . to a second position against a contact 252<SP>1</SP>a . . . . This interrupts the current to solenoid 203<SP>1</SP> and so disables pawl 203. The pin will pass away from the switch 210a . . ., but the switch 216a . . . will remain in its second position. Consequently a solenoid 226a . . . will be periodically energized through a continuouslyoperating interrupter 232 and a pawl 228a will rotate a ratchet-wheel 227a . . . until a cam 223 on cam-wheel 222a . . . closes a switch 221a . . . to energize a solenoid 219a . . . , which restores the arm of switch 216a . . . to its first position, so re-activating pawl 203 and putting solenoid 226a . . . out of action. The circuit is such that the effect of two or more pins is summed as before. The switch 216a . . . may be shifted to the first position by cams 223 and to the second position by pins 209.