Doublecylinder Machines

Double-cylinder circular knitting machines are made up by a base whose central zone houses two circular needle-beds positioned vertically at 180°; the two needle-beds are called lower and upper cylinder.

Double Cylinder Sock Knitting Machines

Picture 114 - Knitting head of a double-cylinder machine (with fixed cam frames and rotating needle-beds)

Picture 114 - Knitting head of a double-cylinder machine (with fixed cam frames and rotating needle-beds)

The needles are arranged in opposite grooves; these machines feature a single series of double latch needles.

Double latch needles have no butt; therefore an external element must control the needle and drive its movement. This element is called slider. The machine incorporates two series of sliders: one is positioned on the lower cylinder and another one is positioned on the upper cylinder; both series are driven by cams.

The main elements making up the slider are shown in the following picture:

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Picture 115 - Slider for a links links machine

The feed systems are so arranged to cover the whole profile of the cylinders; each feed system is equipped with its yarn guide.

In these large-diameter circular machines generally the cam frame rotates while the needle-bed and the spool rack stand still.

The technical characteristic of this machine is that, to realize the knit stitch structures, the needles can be transferred from one needle-bed to the other one, instead of transferring the loop from one needle to another one.

Double-cylinder circular knitting machines have been specifically designed to manufacture patterns with plain and purl knitting effects, the latter also called links-links effects. The most usual types of stitch carried out on these machines is the plain stitch - that can be obtained by making all the needles operate on the lower cylinder - and the purl stitch, obtained by making all the needles operate on the upper cylinder. The base links links stitch pattern is obtained by alternating one plain stitch course with a purl stitch one; in this case the needle passes from the lower cylinder to the upper one and vice versa after knitting each course.

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