Patent GB-867412-A (GB)
Title: Knitting machine yarn striping mechanism
IPC: D04B9/30
Filed: 1957-04-26
Abstract: 867,412. Knitting-machines. SINGER-FIDELITY Inc. April 17, 1958 [April 26, 1957], No. 13392/57. Class 74 (2).  A rotary trick wheel, on which is detachably mounted a circumferential series of blades, is operated in timed relation with the needle cylinder and actuates a plurality of yarn handling fingers and a yarn change mechanism, the fingers each delivering yarn selectively from an associated one of a plurality of individual yarn sources to the yarn change mechanism, for substitution thereby for another yarn then feeding to the needles. Interchangeable yarn selecting fingers 13 are rocked about a shaft 18, between full-line and broken-line positions, by a trick wheel 20 rotated on a fixed shaft 9 through an eccentric on a continuously rotated shaft 22. The eccentric actuates two pawls 31, 34, either of which can engage the teeth of a ratchet-wheel 32 on one end of the trick wheel. The ratchet-wheel is normally racked round by pawl 31, the other pawl 34 being disabled by an arm 36. From time to time, however, one of a plurality of lugs 33, attached to the ratchet-wheel, disables the pawl 31 ; thus the rotation of the trick wheel is interrupted at intervals determined by the spacing of the lugs. The duration of each interruption is determined by the spacing of pins 50 on the side of a pattern chain 39, one of these pins ultimately being brought under a tooth 53 on a rocker arm 52 (as the chain is advanced by a sprocket 40) which, through linkages, withdraws the arm 36 from under the pawl 34, which can then move the ratchet-wheel 32, to bring the operative lug 33 from under pawl 31. The chain sprocket 40 is rotated through a ratchet-wheel 42 which it bears, a pawl 46 engaging the ratchet and being continuously oscillated from another eccentric on the shaft 22. The action of the pawl is modified by a flange 43 freely rotatable with respect to and projecting radially beyond the periphery of the ratchet. The periphery of the flange bears teeth of which every alternate one is aligned with and corresponds in depth with a tooth of the ratchet 42, so that it does not hinder the action of the pawl 46, which accordingly advances the chain. The intervening teeth of the flange are shallow so that the ratchet 46, whilst advancing the flange, will miss the ratchet 42. Thus only one stroke in every two of the ratchet advances the chain. The pawl may be thrown out of action manually by means of a rod 6. The sprocket 40 is braked by the friction of a spring 10. A continuously oscillated but normally bluffed pawl 62 associated with a ratchet-wheel 63 on a pattern drum 64 is rendered operative, when required to advance the drum, by lugs 39 on the chain which act through linkages to withdraw an arm 60 from the path of a pin 61 carried by the pawl. Butts 70, variably positioned on bits 66 carried by the trick wheel, move the yam selecting fingers singly, as required, into the broken line position, in which their yarns lie in the path of a sweep 17 associated with a severing and knotting device. Whenever a yam selected finger is so actuated, another butt 67 on the bit operates through a trigger finger 93, pivoted on shaft 18, to remove a plate 91 from under a pawl 83, allowing the pawl to enter a notch in a continuously oscillated lever 87. An operative connection is thereby established between the lever 87 and shaft 73 carrying the sweep, and the sweep is thus actuated to carry the selected yarn to the severing and knotting mechanism. Synchronously with the actuation of the yarn changing and knotting, and severing devices, a third butt 68 on the bit rocks a finger 102, also pivoted on the shaft 18, to move a link 103 endwise and allow the operation of a switch 108 to slow down the machine during the period of yarn substitution. Specification 219,313 is referred to.