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a machine used to make knitted fabrics or garments. A knitting machine forms loops of yarn and connects them into various knits (seeLOOPING and KNIT STRUCTURE).
Knitting machines differ in purpose, design, and type of knitting needles. All knitting machines may be classified according to the number bf knitting needles per unit length of the needle cylinder. The most widely accepted system uses the English inch (1 inch = 25.4 mm) to measure the length of the needle cylinder. Machines produced in the USSR range in gauge from 3 to 36. The higher the gauge, the finer the fabric produced. For example, 34-gauge machines are used for knitting fine stockings; here, the gauge corresponds to the spacing of the needles 0.75 mm apart in the needle cylinder.
The principal working parts of a knitting machine are the looper, the yarn feed motion, and the take-up motion. The looper contains the needle cylinder with the needles, sinkers, a presser (for spring needles), yarn guides, and other elements. The sinkers, blades with complex shapes, bend the yarn into loops and move the yarn along the shaft of the needle (if the needles are stationary) or hold it (if the needles are moving); one sinker is usually positioned in each space between the needles. The presser, in the form of a wedge, plate, or disk, presses on the needle hook and prevents the loops from falling into the hook.
When the yarn is laid on the needles, the yarn feed motion maintains a specific and constant tension, with the aid of the yarn guides, brakes, take-up motions, and other attachments. In some yarn feed motions, the length of yarn is measured off for each loop row. The yarn may be fed in individual strands (in weft-type machines) or in groups (in warp-type machines). The take-up motion draws the finished knitwear off the needle cylinders while maintaining a constant tension. The material may be drawn off by means of tension created by the weight of the take-up motion or a separate weight, or it may be accomplished by means of rollers.
The knitting processes are automated by mechanisms that control the consistency of feed and yarn tension and the proper working order of the needles; they also rectify any defects that may appear, such as running loops. In full-fashioned machines, various special mechanisms transfer the loops when the width of the cloth is altered, form separate loop rows, introduce reinforcing yarn, alter the density of the knit, and form complex, three-dimensional shapes in such articles as hosiery and gloves. Electronic control devices have been developed for selecting or introducing the needles in knitting patterned and open-work weaves. In knitting artificial fur, circular knitting machines are used that have miniature carding devices in each loop-forming system; these devices knit the tufts of long fibers into loops to form a nap.
The productivity of knitting machines, in million loops per min, ranges to 3.74 for warp-type machines, 5.94 for circular knitting machines, and 1.44 for automatic circular hosiery knitting machines. Knitting machines manufactured in the Federal Republic of Germany, the USA, Great Britain, Czechoslovakia, and the German Democratic Republic are widely used. The further development of knitting machines is aimed at increasing the gauges available, increasing the number of loop-forming systems, and automating the knitting process.
In addition to industrial knitting machines, home hand-knitting machines and devices are also produced. The primary assemblies in hand machines are the loop-forming elements (latch needles and sinkers), carriage, and row counter. The carriage controls the action of the needles and the sinkers; it is moved by hand along guide tracks. The knitting devices have pull-out hooks, a rack with pins, on which the loops are manually hung, and straightedges, by which the hooks are moved and the tightness of the knit is adjusted.
REFERENCESKatsenelenbogen, A. M., and O. D. Galanina. Mashiny i tekhnologiia osnovoviazal’nogo proizvodstva. Moscow, 1966.
Shalov, 1.1., and K. D. Mikhailov. Mashiny i tekhnologüa kruglochu-lochnogoproizvodstva. Moscow, 1968.
Gontarenko, A. N., V. D. Khudin, and L. A. Sirokhin. Odinarnye kotonnyye mashiny dlia proizvodstva verkhnego trikotazha. Moscow, 1973.
Felkin, W. A History of the Machine-wrought Hosiery and Lace Manufactures. London, 1867.
I. I. SHALOV