Method and device for backtracking thread chains with a two-needle overlock sewing machine

摘要

Thread chain sewing method and device for use in the two-needle overlock sewing machine wherein an inner chaining-off finger (12) is arranged retractable from its advanced position in which it is parallel to an outer chaining-off finger (13) to a direction opposite to the fabric material feeding direction. (a) The inner chaining-off finger (12) is held in its advanced position during a sewing process and a thread chain forming period right after the finish of sewing process in a sewing machine operation. Thread chains (A, A') formed before the start of sewing process are entangled only around the outer chaining-off finger, (12) while thread chains formed right after the finish of sewing process are bridged inner and outer chaining-off fingers (12) (13).