7⁄1 × 8 = 56's. 7⁄3 × 8 = 18⅔. 7⁄4 × 8 = 14's.
Example 47.—A fabric with an average counts of 20's is required in two materials, one giving two-fifths of weight and the other three-fifths, find the counts of each.
5⁄2 × 20 = 50's. 5⁄3 × 20 = 33⅓.
CHAPTER VII
Bearded Needle Knitting
The type of knitting instrument employed is responsible for a convenient division of the industry according as the machines are fitted with the latch or the bearded needle. The latch needle has already been described when it was observed to be independent in action. Each needle is free to prepare and complete its own loop, this being done in rapid succession as the cams traverse the heels or butts. In bearded needle knitting the process is quite different, and a number of separate parts require to co-operate with the needle for stitch formation. Fig. 29 gives a clear view of the construction of the bearded needle, also known as the spring needle, consisting of a piece of steel wire specially tempered with one end bent over into the form of a spring or beard. The stem of the needle is marked S, the beard is indicated by B, and the stem has a groove D into which the beard is pressed during loop formation. It is satisfactory to learn that this branch of needle manufacture has always been efficiently carried on by the British maker. The needle is usually fixed in what is termed a lead into which it is cast in a molten condition, each such frame having its corresponding mould according to gauge. The lead is used as the basis of gauge for the frame and each lead as a rule has two needles cast in it for the great majority of machines of this character. These leads are fixed together in a bar which lifts in sections, and to replace any needle the clamp is unscrewed, the lead lifted out, and a new one inserted in its place.
Figs. 29, 30, 31, 32, 33
Stitch Formation on Bearded Needles.—The process of stitch formation by means of the bearded needle is indicated in the series of diagrams 30 to 33, which represent the operation as performed on a modern rotary frame of the Cotton's Patent type. The needle is much less independent in action than the latch variety, and to complete the making of the loop several auxiliaries are indispensable. Of these the most important are the presser P which in this system is stationary, and the sinker S with its throat A and its nose B. For the knock-over of the loop is required the aid of the discharging piece DP which is also stationary. In Fig. 30 the needle is seen in the act of descending, having just received the thread T from the yarn-carrier and which thread has entered under the open beard B of the needle. At this stage the loops of the fabric F are seen hanging on the needles down on the stem and under the nose B of the sinker. Fig. 31 shows the next operation where the needle drops still farther and moving towards the left has its beard pressed into the groove D, just after which the needle descends still farther and receives the old loop from the needle stem on to its closed beard or spring. The stage shown in Fig. 32 is known as knocking over or discharging where the needle is noted to have moved to the right away from the presser, whilst it has also sunk still farther between the discharging pieces DP. These latter perform their function solely by reason of their position, and act as supports or rests for the stitches as they are drawn down between the pieces as indicated. In this it is very important that the needle should draw the new stitch properly through the old one as any defect in knocking-over results in faulty fabric. In Fig. 33 the needle is seen to be rising once more into the normal position ready to receive another supply of yarn from the thread carrier. The stitch-forming process is so important that it may be well to summarize the whole operation under various headings.
Laying the Yarn.—This operation is performed by the thread-carrier in the usual manner and it draws its thread across the sinker throats from one side of the frame to the other, regular delivery of thread being most important at this stage.
Sinking the Loops.—This operation is illustrated in Fig. 30 where the sinker is noted to have pushed the thread already supplied and is sinking it over the stems, every second needle being dealt with in this way.