Circular knitting machine incorporating a device for renewing a needle selection at at least one yarn feed

A circular knitting machine of the type having at least one needle cylinder and a device for renewing a selection of needles at at least one yarn feed, comprising:

• at least two yarn feeds
• at least one associated pattern selection device
• a plurality of tiltable pattern jacks associated with said needles and provided with butts for selection by said pattern selection device
• a ring cam having raised portions associated with said yarn feeds to guide the jacks selected to bring the respective needles to knit
• a surface radially inside said ring cam for guiding the jacks selected not to follow said raised portions
• a guiding cam arranged adjacent to at least one of said raised portions on the inward side thereof
• said guiding cam extending in a circumferential direction at least as far as the next following portion of said raised portions
• said guiding cam being formed of two members,
• a first member having a shape capable of an engagement with the lower ends of said jacks, so as to bring radially inwardly the jacks selected not to climb along said one portion of said raised portions of said ring cam,
• said member being movably mounted on said ring cam for a transverse motion to and from said ring cam,
• a second fixed member defining with said first member a switching cam adapted to hold said selected jacks radially on the inside when said first member is in an operative position and to return said selected jacks radially to the outside into a selection position when said first member is in an inoperative position.