| 摘要 |
PROBLEM TO BE SOLVED: To apply an appropriate tension to a bobbin thread at a timing desired by a user. SOLUTION: This bobbin thread tension control device 1 of a sewing machine includes: a magnetic body 6 extractably/retractably provided relative to a bobbin thread guide part 53 formed at a shuttle hook 5 for retaining a bobbin on which the bobbin thread T is wound and guides the bobbin thread, and capable of applying/releasing the tension to the bobbin thread guided to the bobbin thread guide part; an electromagnet 8 provided at a position facing the magnetic body on the other side of the bobbin guide part, and generating a magnetic field in its periphery by the energization to extract/retract the magnetic body relative to the bobbin thread guide part; and an energization control means 9 changing the direction and the magnitude of a current for energizing the electromagnet according to the tension to be applied to the bobbin thread. COPYRIGHT: (C)2008,JPO&INPIT
|
