Knot detecting and rejecting attachments for unifil-type bobbin winding machines

Claim 1

In a bobbin-winding machine for fabric-forming machines having automatic bobbin change when a bobbin has become exhausted and which machine includes a full bobbin magazine, bobbin-winding means, a guide track to the magazine for full bobbins, doffing cycle means initiated by sensing means which determine that a bobbin is fully wound, which doffing cycle includes stopping winding, doffing the wound bobbin, cutting the yarn end, and causing it to fall through the guide track into the magazine, means for introducing an empty bobbin and means for returning the winding mechanism to initial position at the end of the doffing cycle, the winding machine having means for receiving a plurality of yarn or thread packages which have their end yarns tied to the beginning yarns of the next succeeding package, the improvement which comprises, in combination, a. a trippable trip plate having an opening positioned so that yarn wound onto bobbins passes therethrough, the opening being of dimensions such that yarn passes through without tripping the plate but knots cannot pass through, and trip the plate, b. the trippable plate including a pivot on the plate and a trippiNg force much less than the breaking strength of the yarn and less than the force exerted by a knot, c. means actuated by the pivoted tripping plate for actuating a switch with solid contacts and insensitive to vibration, d. a plurality of solenoids actuated by the switch, one solenoid initiating a doffing cycle even though a bobbin being wound is not completely wound and a second solenoid tilting the guide means to a position whereby a bobbin in the doffing cycle cannot pass into the magazine but is deflected to one side, e. a knot-containing bobbin receiving container positioned so that when a bobbin is doffed in the cycle induced by the switch it is conducted to the container, and f. means actuated by the end of the doffing cycle for restoring the tripping plate into position and resetting the switch, whereby bobbin winding proceeds with normally actuated doffing cycles at the time of a fully wound bobbin so long as there is no knot in the yarn and a knot-wound bobbin doffing cycle is only initiated when a knot in the yarn passes through the tripping plate.