a knitting machine for manufacturing hosiery. Circular knitting machines are the most common type, producing approximately 95 percent of all hosiery made. They are characterized by continuous loop formation and the absence of high alternating loads.
Circular knitting machines are used to knit all types of hosiery. The raw materials used are chiefly polyamide and cotton yarns. Machines of this type have internal specialization for various types of finished products. Women’s socks are usually made on single-cylinder (single-knit) machines with two, four, or eight loop-forming systems. The primary working elements are latch needles, housed in grooves along the periphery of a needle cylinder, and sinkers set in radial grooves of a ring around the upper edge of the cylinder. The motion of the needles and sinkers along the grooves of the rotating cylinder is imparted by fixed cams that act on the base of the needles and the sinkers. The interaction of the needles and sinkers with the yarn, which is fed to the needles from bobbins through a yarn guide, forms the loops. The sock is drawn through the inside of the needle cylinder by a current of air from a special fan. The finished sock is then tossed into a bin. The toes are usually sewn on special sewing machines (linking or serging types). The newest automatic circular hosiery machines complete the sock with a closed toe.
Patterned full-length stockings are knit on single-cylinder hosiery machines equipped with a pattern mechanism. Three- and four-system machines can knit stockings in three and four colors, respectively. Two-cylinder (double-knit) automatic circular machines are used chiefly to make children’s socks and all types of full-length stockings. Their main distinction is that they knit articles with high extensibility (ribbed fabrics). The primary working element of such machines is a two-headed latch needle that can be automatically shifted from the lower needle cylinder to the upper and back again. This type of needle motion is used to switch to ribbed (double-face) or reversible knit structures.
Technical specifications for hosiery machines include the diameter of the needle cylinder (2.5–4.5 inches), the number of needles in the cylinder (40–480), the gauge (measured by the number of needles to 1 inch of the cylinder circumference), the number of loop-forming systems (from one to 12), and the presence of special mechanisms. The productivity of hosiery machines varies greatly, depending on the type of article and the type of machine. The time it takes to knit a woman’s sock varies from 1 to 4 min; full-length stockings require from 0.5 to 4 min.
Small quantities of hosiery are manufactured on flat knitting machines and sometimes on ribbers and circular warp-knitting machines.
REFERENCESShalov, I. I., and K. D. Mikhailov. Mashiny i tekhnologiia kruglochulochnogo proizvodstva. Moscow, 1968.
Artamonov, Ia. E., and B. V. Gubanov. Kruglochulochnye avtomaty 34 klassa. Moscow, 1970.
I. I. SHALOV