Patent ID: 7603957
Filing Date: 2009-10-20
Classification: D05B

Abstract:
1. A thread cutting device of a sewing machine, the thread cutting device comprising: a thread catching member having a catching portion, wherein the thread catching member moves back and forth across a path of a lower thread reeled out from a bobbin so as to catch the lower thread by the catching portion, and cuts the lower thread by cooperating with a fixed knife; a first power transmitting portion which transmits a power to the thread catching member; a sewing machine motor operable to rotate a lower shaft; a first cam member provided on the lower shaft, wherein the first cam member transmits a first moving force to the thread catching member through the first power transmitting portion; a stepping motor operable to drive the thread catching member; a second power transmitting portion which transmits a second moving force from the stepping motor to the thread catching member through the first power transmitting portion; and a cutting control unit operable to drive the stepping motor to move the thread catching member through the second power transmitting portion when catching the lower thread, and to drive the sewing machine motor to move the thread catching member through the first cam member when cutting the lower thread.