Automatic severing of the roving when the wound bobbin is doffed from a roving frame uses a press finger plank with a structured movement to act on the weak point of set roving reserves to give a constant remaining length

摘要

To sever the roving (2) automatically when the bobbin (1) is doffed at the roving frame, the roving (2) is fed as far as a press finger plank (10) where the roving is severed between the press finger plank and the outer surface of the wound bobbin. The roving is wound into at least a half-coil (6) and a roving reserve (A-D) over the winding (15) around the bobbin (1). The roving reserve (A-D) is unwound by reversing the bobbin (1) rotation. The press finger plank (10) is moved across the bobbin circumference by a given amount, and the roving (2) is severed at the weak point (C) by the movement of the press finger plank. The coils (6) of roving (2) over the windings (15) on the bobbin (1) are wound around the bobbin sleeve (3). The roving reserves are in three sections (A-D) with a length of roving from the upper edge (A) of the wound cone (12) of the bobbin winding (15) to the lower edge (B) of the cone (12). A roving length is between the lower edge (B) of the end cone (12) to the anticipated weak point (C). A length of roving runs to a point (D) which is the roving length remaining after separation by the press finger plank (10). On reversing the rotation of the bobbin (1), a false twist is developed with a raised number of twists in the first length (A-B) and a reduced twist count in the remaining lengths (B-D). On moving the press finger plank (10) into place, the roving length in the second and third sections (B-D) is equal to the yarn length from the start of the second section (B) to the press finger plank position. The third section between the end of the second length and the press finger plank position is stabilized by a twist increase which also sets its length. The press finger plank is advanced into the roving weak position (C) to sever the roving (2).