| 摘要 |
PROBLEM TO BE SOLVED: To facilitate a change of thread supply in order for alternate single and double thread chain stitches. SOLUTION: This buttonhole sewing machine for buttonholing a material 32 has a thread supply mechanism 33 disposed in the path of a needle thread 34 supplied in a feed direction 48. The thread supply mechanism 33 has a swing thread lever 41 with an opening for guiding the needle thread 34 that passes therethrough. The thread lever 41 is driveable by an operable positioning motor 45 so as to swing between a zero position and several thread feed positions.
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