DEVICE USED ON SEWING OR KNITTING MACHINES FOR CHANGING THE BOBBIN CONTAINING THE LOOPER THREAD

摘要

The invention relates to a device used on two-thread lock-stitch sewing or knitting machines, for changing the bobbin case which contains the bobbin spool, said case being received by a tenon which is located inside the looper. Said device comprises a receiving unit, which has carriers with receiving compartments for the bobbin cases and a gripper device containing at least one retaining element for the bobbin cases. To change the bobbin cases, said retaining element can be displaced along a predetermined track between the receiving unit and the looper. The retaining element (34) has at least one switchable magnet (35) that makes contact with the bobbin cases (4) and in the vicinity of its front wall (7), each bobbin case (4) has a permanent magnet (8), acting as a locking element and co-operating with the tenon (6). The retaining force of the permanent magnet acting upon the tenon (6) is weaker than the force of the switchable magnet (35).