Method and apparatus for automatic maintenance of ring spinning machines, in particular for the automatic rectification of breakages

摘要

In the end-down servicing of a spinning machine by an automatic yarn piecing apparatus, substantially all of the yarn retrieval step of each piecing operation is conducted during downstroke movement only of the ring rail of the spinning machine. Certain yarn-tensioning steps of each piecing operation, including the step of finally recommencing winding rotation of the bobbin at the spinning machine delivery undergoing servicing, are conducted only when the ring rail is moving upwardly and is adjacent the top of a reciprocatory stroke or traverse. In a preferred embodiment reversal of the direction of ring rail movement is sensed by a switching means including actuator and switch elements carried by the piecing apparatus for movement in unison with the ring rail of the spinning machine during part of each piecing operation except when the ring rail reverses its movement, at which time the switching means is actuated by relative movement between its components.