Method of equalizing supply of thread to a plurality of knitting stations

Claim 1

Method of obtaining equal supply of thread to a plurality of knitting stations in multifeed circular knitting machines having rotating thread supply drums over each of which thread is looped to be supplied thereby essentially without slip of the thread over the drum, said method comprising generating a thread speed reference command signal having a characteristic representative of desired speed of the thread being delivered to a first knitting station; separately sensing the speed of the thread supply drum and thus of the thread being delivered to each knitting staTion and deriving, for each knitting station, a sensed speed signal having a characteristic representative of sensed thread speed at the respective knitting station; separately sensing the tension of the thread being delivered to each knitting station and deriving, for each knitting station, a sensed tension signal having a characteristic representative of sensed thread tension at the respective knitting station; controlling the speed of the thread supply drum at the respective knitting station by the tension signal of the respective knitting station to provide constant thread tension between the respective supply drum and the respective knitting station; comparing the respective sensed speed signals of each knitting station with said thread speed command reference signal and deriving, for each knitting station, a speed error signal; and adjusting the knock-over point at the respective knitting stations in dependence on the respective speed error signal whereby the amount of thread being delivered to respective knitting positions will be controlled by the constraint of the reference command signal.