Abstract: A unit is disclosed for transmitting motion to the hosiery suction tube in a circular knitting machine of the type having a fixed supporting plate to which a cylinder support with a vertical axis, an internal hosiery passage tube that is coaxial to the cylinder support, and an underlying perforated tube are rotatably coupled. The unit has respective flanges rigidly coupled below the cylinder support and above the perforated tube and supporting respective pluralities of permanent magnets that are distributed in an annular fashion and constitute a magnetic coupling between the flanges for the rotary actuation of the perforated tube. A collar of a material that has high magnetic reluctance is arranged in the air gap formed between the rings of facing magnets and has a device for rotary coupling to the hosiery passage and a device for selective coupling to said flanges or to said fixed supporting plate for causing or stopping the rotation of the hosiery passage tube.

Abstract: A circular knitting machine of elastic needle type provided with a cam for flexing all the needles into their trick before they are raised to seize the feed yarn, in which the selection between those needles to be maintained flexed and those needles to be allowed to return to their normal configuration is made by axially slidable sliders positioned below each needle contained in the tricks.

Abstract: A circular knitting machine in which the inactivation or activation of a vertical jack below each needle is determined by a flexible fork located radially of the cylinder within a ring structure completely surrounding the machine cylinder and rigid therewith. A number of forks and radial grooves equal to the number of needles is provided, said forks being able to flex within said grooves and being selected by a magnetic force.