抄録
The drafting system of woollen ring spinning with false twisting has its objective to achieve such a drafting effect as in woollen mule spinning. This is an idea of levelling the uneveness of a sliver by concentrating twists on its thin portion to give greater draft to its less twisted, thick portion.
The previuos report pointed out a marked difference between the twist densities in the regions from back rollers to a tube entrance and from the tube entrance to the front nip. The twist density is smaller at the part from the tube entrance to the front nip than in the other. It may be said, therefore, that the operation of levelling the sliver may be performed only in this narrow zone.
This report deals in detail the operation of levelling the uneveness of a sliver by experimenting the influences of the thickness upon a variation in twists in the false twisting zone.
(1) In the false twist drafting, the drafting is given mainly in the less twisted zone between the tube and the front nip. (Fig. 1 and 2)
(2) In the case of twisting at one place, a sliver is twistless in the zone between the tube and the front nip in steady state. When an unven sliver enters this zone, the S twist and the Z twist appear alternately. (Fig. 5)
(3) In the case of twisting at two places, there are twists in a sliver in the main draft zone in the steady state. When uneven sliver enters the zone, a variation occurrs in such a way that its thick portion is less twisted and its thin portion more twisted. (Fig. 6)
(4) The evenness of a sliver is improved by false twist drafting in the zone between the tube and the front nip. The uneven sliver prepared by eccentric rollers was false twist-drafted and examined. It was found that its less twisted and thick portion is more elongated than its more twisted part. (Fig. 7)
(5) The wave length of uneveness of a sliver has a close connection with length of the zone L2. (Fig. 8)
