THREAD-CUTTING DEVICE FOR SEWING MACHINES

摘要

In a prior art sewing machine, the tensioner is released in both directions of the axially mobile gear element (21), and hence the thread tensioner is also opened when the needle thread is seized. In the new design, the motion of the gear element (21) is transmitted via a one-way coupling (53), and therefore the thread tensioner is open only while the needle thread is being tensioned.