Patent ID: 8794167

Claim:
A sewing machine comprising: a thread take-up lever formed in a swayable manner; a needle thread control section that is disposed at an upstream position on a needle thread path of the thread take-up lever and that includes an upstream grip section which includes an upstream grip section main body for pinching to thereby grip a needle thread and an upstream actuation section for switching, with respect to the upstream grip section main body, between a closed state in which the needle thread is gripped and an open state in which a needle thread is released from a gripped state, a downstream grip section which is disposed at a downstream position on a needle thread path of the upstream grip section and which includes a downstream grip section main body for pinching to thereby grip a needle thread and a downstream actuation section for switching, with respect to the downstream grip section main body, between a closed state in which the needle thread is gripped and an open state in which the needle thread is released from a gripped state, and a turning section which turns the needle thread existing between the upstream grip section main body and the downstream grip section main body and which has a turning arm to contact the needle thread and a needle thread motor to turn the turning arm; and a control section, in a control zone for each stitch, that—in a torque control zone including at least a portion of a zone from a bottom dead point to a top dead point of the thread take-up lever during which the thread take-up lever draws the needle thread with respect to processed fabric to be sewn with the needle thread—controls the needle thread motor in accordance with a torque value in such a way that tension is imparted to the needle thread against a direction in which the thread take-up lever draws the needle thread while the upstream grip section main body is closed and while the downstream grip section main body is opened, to thus impart rotating force to the turning arm, and that—in a position control zone which is at least a portion of a zone other than the torque control zone achieved while the upstream grip section main body is opened and while the downstream grip section main body is closed—controls the needle thread motor in accordance with angle position data pertaining to the needle thread motor in such a way that an angle of the needle thread motor returns to an initial angle position of the needle thread motor which is a rotational position of the needle thread motor, thereby imparting rotating force to the turning arm to thus draw the needle thread from an upstream position.