Sewing machine lower thread looper

摘要

The looper, with lower thread combinations in a sewing machine, has a thread holder which is moved to and from the needle by a pull and slide action. The movement is by a flexible cable, belt or chain as a rigid extension on a straight line or in a closed or open curve. The path of the lower thread bobbin has a movement path similar to a shuttle, where the tension and the yielding of the upper thread are set by one or more disc tensioners with synchronised control.