DOUBLE LOCK STITCH SEWING MACHINE PROVIDED WITH ROTATION SAFETY STRUCTURE FOR BOBBIN CASE

摘要

PROBLEM TO BE SOLVED: To mitigate the damage to a needle loop at the time of the winding of a spool case. SOLUTION: A double lock stitch sewing machine is provided with a looper (18) held by a holder (58), provided with a bobbin case (21) internally supported rotatably and rotated around a vertical axis (26). The holder (58) is provided with a first rotation safety structure (56) blocking the accompanying rotation of the bobbin case (21) and a second rotation safety structure (57) limiting the return rotation of the bobbin case (21). The first rotation safety structure (56) is arranged at a position separated from a stitch hole (17). The second rotation safety structure (57) is abuttable to the bobbin case with an abutting surface (46) formed on a fixed cantilever arm (45) while evading a cam provided on the lower side of a floor plate (13) at a position near the stitch hole (17).