Cop winding at a ring spinning machine with a clamp

摘要

During the operation of a ring spinner, on setting the back winding at the end of winding a cop, the ring frame (20) is moved downwards according to the yarn delivery from the drawing unit (12). The yarn delivery, on the downwards movement of the ring frame (20), and the surplus yarn (10) length through the balloon is compared with a straight line yarn feed between the drawing unit (12) and the ring frame (20). The yarn is held within a given tension range on one side, and is held at a given angle round the cop (8), at values which are not below the set levels. When the yarn (10) is brought from the uppermost position at the cop (8) to the clamp (28) under the cop (18), the ring frame (20) is moved with a simultaneous delay action at the drawing unit drive (12a) and the spindle drive (22). After forming an overwinding at the cop (8), the ring frame (20) is initially moved downwards in an accelerated movement phase and is decelerated before reaching the lower section (8a) of the cop (8). The ring frame (20) is then lowered further, in a second accelerated movement phase before the yarn (10) is bought to the clamp (28), and then decelerated until it comes to rest. The ring frame (20) remains at the lowest position at the clamp (28) only during max. two loops of the overwinding length at the spindle (6) and especially three-quarters of a loop. The rate of the ring frame (20) descent, between the overwinding and underwinding, after the cop is finished, is in relation to the spindle (6) rotary speed and/or the drawing unit (12) delivery speed and is varied so that 0.5-3.0 yarn (10) back windings and loops are formed. During back winding, the spindle (6) speed is set at 6000 rpm and for <= 1000 rotations. The second acceleration phase for the ring frame (20) is when it is at the lower section (8a) of the cop (8). During the descent of the ring frame (20), the spindle speed and drawing unit delivery speed are reduced, but not as far as zero. The ring frame (20) is raised from the bottom position, over the clamp (28), before the drawing unit (12) and the spindle (6) come to rest. The spindle (6) continues to rotate for a short time span, after the drawing unit drive (12a) has stopped. The drawing unit (12) continues to operate for a short time span, after the underwinding has been formed and the ring frame (20) is lifted from under the underwinding crown and is over the clamp (28), in order to deliver a length to allow the guide (14) under the drawing unit (12) to be swung upwards. The downwards acceleration of the ring frame (20) prevents any tangles being formed in the yarn (10) between the drawing unit (12) and the traveler (18), and prevent the yarn tension level being breached. The back winding, at the lower section (8a) of the cop (8), is laid on the cop (8) at an angle of /-30 deg to the horizontal. During the second downwards acceleration phase of the ring frame (20), the angle of the back winding is not less than 45 deg to the horizontal, so that the yarn (10) is taken at least at this angle from the lower section (8a) of the cop (8) over the underwinding crown to the clamp (28). The position of the ring frame (20) is determined during its movements by a path movement sensor (16a) pref. at the ring frame drive (16). The control (24) is programmed so that, when the lowest setting of the ring frame (20) at the clamp (28), the yarn delivery at the drawing unit (12) is measured by a rotation sensor (12b) at a drawing unit roller. The delivery interruption occurs when a given length is wound as the underwinding at the clamp (28) round the spindle (6). An Independent claim is included for a spinning machine with a power section (24a) at the control (24) which is set to brake the spindle (6) and drawing unit (12) at the end of cop winding. It gives the alternate accelerated and decelerated downwards movement for the ring frame (20). Preferred Features: The control (24) has a power section (24a), a memory (24b), input unit (24c) and a computer unit (24d). An underwinding crown is fixed over the clamp (28) which moves along the spindles (6), and is attached to the clamp (28) at the clamping position for the yarn (10) at the underwinding crown. The clamp (28) is spring loaded on the opposite side to the ring frame (20), on the longitudinal line of the spindle (6). The drawing unit yarn guide (14), over the spindle (6), can be swung upwards. The memory (24b) has storage for the rotation of the cop mass, the ring dia. and cop dia., the length of the winding sleeve and the yarn thickness.