Knitting machine yarn feeding apparatus

Claim 1

In combination with a knitting machine having a rotating drive member, a plurality of needles moved by the drive member for knitting fabric and at least one yarn package from which yarn to be knit is supplied to the needles, yarn feeding apparatus comprising: means interposed between a yarn package and the needles for positively engaging a corresponding yarn to be supplied for knitting, variable speed drive means drivingly connected with said yarn engaging means for driving the same in rotation and thereby for withdrawing yarn from the corresponding package and fEeding the yarn to the needles as required for knitting, first control means operatively connected with said drive means for controlling the rotational speed thereof, tachometer means operatively responsive to said drive means for sensing rotation thereof and for generating a first signal indicative of the speed of rotation thereof, rotation means operatively responsive to the drive member for sensing rotation thereof and for generating a second signal indicative of the speed of rotation thereof, yarn tension means operatively responsive to tension in the yarn between the needles and said yarn engaging means for sensing tension therein and for generating a third signal indicative of the level of tension therein, standard means for generating a fourth signal indicative of a desired level of tension, and means operatively connected with said first control means and operatively connected with said tachometer means, said rotation means, said tension means and said standard means and including switch means for selecting between correlation of said first and second signals and correlation of said third and fourth signals and second control means for varying the rotation of said drive means in accordance with any difference from a predetermined correlation between a selected pair of signals, whereby yarn is withdrawn from the corresponding yarn package as demanded for knitting by the needles.