Patent ID: 7380511

Claim:
An automatic thread cutting device for a sewing machine which is provided with a horizontal loop taker, the automatic thread cutting device comprising: a thread catching means operated in response to a first instruction signal for cutting both of the upper and lower threads of the sewing machine to reciprocatingly move in one direction and in a return direction along a predetermined course to catch the upper and lower threads, the thread catching means operated in response to a second instruction signal for cutting the upper thread only of the sewing machine to reciprocatingly move along a predetermined course to catch the upper thread while moving below the lower thread, a thread cutting means for cutting the upper and lower threads which may be caught by the thread catching means, a thread regulating means operated in response to the first instruction signal to move down the lower thread to a position where the lower thread is caught by the thread catching means as the latter is reciprocatingly moved, wherein said thread regulating means includes an elongated bar for pressing down the lower thread, the elongated bar extending along the reciprocating path of a thread catching member of the thread catching means and simultaneously extending across and above the lower thread which extends from a bobbin carried in the horizontal loop taker to a needle dropping hole of a needle plate, said thread regulating means further including swingable arms connected to the opposite ends of the elongated bar respectively and operated to move down the elongated bar only when the thread catching member is moved in said return direction of reciprocating movement.