| 摘要 |
A rotary shuttle device of a sewing machine is provided to catch a bottom thread on a bobbin case body securely even through a tension spring misses the bottom thread, thereby smoothly performing a sewing operation, by using a tension-supporting spring installed on a draw path of the bottom thread at a position before the tension spring. A rotary shuttle device comprises a hook body(20) installed on a driving shaft(10), a bobbin case housed in the hook body and consisting of a bobbin case base(30) and a bobbin case body(50), and a bobbin(40) installed within the bobbin case. A bottom thread is wound around the bobbin. An incision line-typed draw hole is formed in one side of the bobbin case body. The bottom thread is unwound from the bobbin case, and then guided to a sewing region through the draw hole. A tension spring(55) guides and supports the bottom thread, which is guided through the draw hole. A tension-supporting spring(57) is formed in an inlet portion of the draw hole of the bobbin case body. The tension-supporting spring hinders the separation of the bottom thread, which is missed by the tension spring.
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