Patent ID: 8584981

Claim:
A positive yarn feeder, comprising: a motorized yarn-winding drum adapted to have a plurality of loops of yarn wound thereon and driven to rotate for drawing said yarn from a reel and feeding said yarn to a general downstream machine, a movable guiding member, which is biased to slideably engage the yarn unwinding from the drum and to deviate a path of the yarn by a spring acting in contrast to the tension of the yarn, thereby generating a reserve releasable in response to tension peaks on the yarn, a stop that defines a position of maximum deviation of the yarn by limiting a stroke of said guiding member, driving means operable for applying a load to the spring with the guiding member abutting against said stop, and a control unit for controlling said driving means, which is programmed to adjust said load as a function of a desired feeding tension, said spring having one end operatively connected to the guiding member and an opposite end connected to the driving means, and said driving means comprising a linear actuator having an operating rod, said spring being a coil spring suitable to act by traction and having a first end attached to said operating rod of said linear actuator, said coil spring having a second end that is arranged opposite to said first end, said guiding member being attached to said second end.