| 摘要 |
PROBLEM TO BE SOLVED: To strengthen knot tightening in single yarn chain stitches. SOLUTION: This button sewing machine is provided with a vertically moved sewing needle 11, a needle thread take-up 16 vertically moved corresponding to the sewing needle 11, a looper 14 for forming a loop by capturing a sewing thread from the sewing needle 11 at the time of lowering, and a thread tension device 60 for imparting resistance force to the movement of the sewing thread between the needle thread take-up 16 and the sewing needle 11. The thread tension device 60 can switch the imparting of the resistance force to the sewing thread and the cancellation and is provided with an operation control means 80 for executing operation control of providing a period to impart the resistance force to the sewing thread of the thread tension device 60 while the needle thread take-up 16 is lowered and providing the period to cancel the imparting of the resistance force to the sewing thread of the thread tension device 60 while the looper 14 captures the sewing thread and forms the loop. COPYRIGHT: (C)2005,JPO&NCIPI
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