Patent ID: 9016218
Filing Date: 2015-04-28
Classification: D05B,D05C

Abstract:
1. A sewing machine comprising: a plurality of sewing units, each of which includes: a storage section for storing needle thread control torque data for which a needle thread control torque value is stored for each stitch in embroidery data and bobbin thread control torque data for which a bobbin thread control torque value is stored for each stitch in the embroidery data; and a control section that, when performing embroidery sewing according to embroidery data and in connection with the needle thread, in a control zone for each stitch, controls the needle thread motor in each of the sewing units in accordance with a torque value of the needle thread control torque data while closing the upstream grip section main body and while opening the downstream grip section main body such that tension is imparted to the needle thread against a direction in which the thread take-up lever draws the needle thread, thereby imparting rotating force to a turning arm, within a control zone; namely, within a needle thread torque control zone which is a zone including at least a portion of a zone from one dead point to another 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; that controls the needle thread motor in each of the sewing units in accordance with position data pertinent to a needle thread motor angle such that an angle of the needle thread motor, which is a position of the needle thread motor in a rotating direction, returns to an initial angular position of the needle thread motor, while opening the upstream grip section main body and closing the downstream grip section main body, within a position control zone which is at least a portion of a zone other than the torque control zone, thereby imparting rotating force to the turning arm to draw the needle thread from an upstream position; and that, in connection with the bobbin thread, controls the bobbin thread motor in each of the sewing units in accordance with a torque value of the bobbin thread control torque data, within a bobbin thread torque control zone which is at least a portion of a zone from the one dead point to the another dead point of the thread take-up lever.