The Exchange Technique

It is a method for the selection of high-butt and low-butt needles and is mainly used for transferring the stitches from one needle-bed to the other.

By using the needles raising cam on the carriage, it is impossible to lead the low-butt needle to the looping position without the upper one doing the same movement.

The exchange technique allows this possibility.

Near the main group (picture 46) made up of a raising cam and a knock-over cam, there is an auxiliary group of cams, consisting of a mobile raising cam that can assume the knitting position, half-knitting position and non-knitting position, and a fixed lowering cam, which is set half-way.

Cam Plates And Needle Butts

MAIN GROUP:

AUXILIARY GROUP:

  1. = MAIN RAISING CAM
  2. P.D. = MAIN LOWERING CAM
  3. A.S. = AUXILIARY RAISING CAM
  4. A.D. = AUXILIARY LOWERING CAM
  5. A. = HIGH-BUTT NEEDLE T.B. = LOW-BUTT NEEDLE

Picture 46 - Exchange unit

Before hitting the main raising cam, the needles come into contact with the exchange unit.

By bringing: the auxiliary raising cam in knitting position the auxiliary lowering cam in half-knitting position the main tucking cam in non-knitting position the main looping cam in knitting position, the high- and low-butt needles hit the auxiliary raising cam and rise till they reach their maximum height.

Afterwards, since the lowering auxiliary cam is in a half-knitting position, the high-butt needle knocks over while the low-butt needle continues its stroke.

When touching the main cam, the high-butt needle is not affected, since the tucking cam is not knitting; the low-butt needle hits the looping cam which is completely open and completes the knitting cycle.

This technique is usually used with sliders for the stitch formation cycle, since the lowering cams can interfere with the selection carried out by the transfer group; there are no problems when using this system for the stitch transferring cycle.

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