Sewing machine

A sewing machine comprising:

• an arm making up an enclosure of the sewing machine;
• a needle bar case that is provided so as to be slidable in a horizontal direction with respect to the arm and that includes first opening sections made at positions between an upstream grip section main body and a downstream grip section main body in a vertical direction such that a leading end of a turning arm of a turning section can be exposed to the front side, a second opening section which is provided above the first opening section and on which an upstream magnet section fronts, and a third opening section which is provided below the first opening section and on which a downstream magnet section fronts;
• a plurality of thread take-up levers that are provided on a front side of the needle bar case in an exposed fashion and that are provided at downstream positions on needle thread paths with respect to a downstream grip section in a swayable manner;
• a plurality of needle bars provided in the needle bar case;
• an upstream grip section that has
• an upstream grip section main body that is placed on a front side of the needle bar case, that pinches to thereby grip the needle thread, and that has upstream first plate-like sections which is formed from a magnetic substance that is a material attracted by the magnet, and which is provided for the respective needle bars and an upstream second plate-like section which is provided at back side of the upstream first plate-like sections and on a front side of the second opening section and which is formed from a non-magnetic substance unattracted by the magnet, and
• an upstream magnet section that is secured to the arm side and that switches between a closed state in which the needle thread is pinched to thereby grip between the upstream first plate-like section and the upstream second plate-like section by means of attracting the upstream first plate-like section from a back side of the upstream second plate-like section by means of magnetic force and an open state in which the needle thread is released from the gripped state by canceling attraction caused by magnetic force;
• the downstream grip section that is placed at a downstream position along a needle thread path of the upstream grip section and that has
• the downstream grip section main body which is placed on a front surface side of the needle bar case and below the upstream grip section main body, which pinches to thereby grip the needle thread, and which has a downstream first plate-like sections which is formed from a magnetic substance that is a material attracted by a magnet and which is provided for each of the needle bars and a downstream second plate-like section that is provided at back side of the downstream first plate-like sections and on a front side of the second opening section and that is formed from a non-magnetic substance unattracted by the magnet, and
• a downstream magnet section that is secured to the arm side and that switches between a closed state in which the needle thread is pinched to thereby grip between the downstream first plate-like section and the downstream second plate-like section by means of attracting the downstream first plate-like section from a back side of the downstream second plate-like section by magnetic force and an open state in which the needle thread is released from a gripped state by canceling attraction caused by the magnetic force;
• needle thread supporting members that each is provided in the needle bar case and that each supports the needle thread in its horizontal direction at the position of the first opening section;
• a turning section that turns the needle thread existing between the upstream grip section main body and the downstream grip section main body and that has the turning arm which contacts the needle thread supported by the needle thread supporting member and a needle thread motor which is secured to the arm side and which turns 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 in accordance with torque data which are generated from embroidery data and whose torque value is specified for each stitch, while the upstream grip section main body is closed and while the downstream grip section main body is opened, thereby imparting rotating force to the turning arm in an upward direction 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 detects at a starting point of the position control zone a current angle position of the needle thread motor which is a rotational position of the needle thread motor, generates angle correspondence data which specify an angle of the needle thread motor from the current angle position to an initial angle position of the needle thread motor for each angle of a main spindle motor representing a rotational position of the main spindle motor which rotates a main spindle for transmitting power to the thread take-up levers and the needle bars, controls a position of the needle thread motor to its angle of the needle thread motor corresponding to the angle of the main spindle motor as the angle of the main spindle motor changes as a result of rotation of the main spindle motor in such a way that the angle of the needle thread motor returns to an initial angle position of the needle thread motor, to thus impart rotating force to the turning arm in an upward direction and draw a needle thread from an upstream position, turns the turning arm downward so as to recede to a receded position and slide the needle bar case when processing proceeds to control of a next stitch and when a needle thread to be selected is changed, thereby letting the upstream magnet section, the downstream magnet section, and the turning arm come to a position of the selected needle thread.

A sewing machine comprising:

• an arm making up an enclosure of the sewing machine;
• a needle bar housing case that is disposed so as to be slidable in a horizontal direction with respect to the arm and that houses a plurality of needle bars;
• a tabular plate section that is disposed on an upper surface of the needle bar housing case and that is provided with first opening sections made at positions between an upstream grip section main body and a downstream grip section main body in a vertical direction such that a leading end of a turning arm of a turning section can be exposed to the front side, a second opening section which is provided above the first opening section and on which an upstream magnet section fronts, and a third opening section that is placed below the first opening section and on which a downstream magnet section fronts;
• a plurality of thread take-up levers that are axially supported by the needle bar housing case in a swayable manner, that are provided on a front side of the needle bar housing case in an exposed fashion, and that are provided at downstream positions on needle thread paths with respect to a downstream grip section;
• an upstream grip section that has
• the upstream grip section main body that is placed on a front side of the plate section, that pinches to thereby grip a needle thread, and that has upstream first plate-like sections which is formed from a magnetic substance that is a material attracted by the magnet, and which is provided for the respective needle bars and an upstream second plate-like section which is provided at back side of the upstream first plate-like sections and on a front side of the second opening section and which is formed from a non-magnetic substance unattracted by the magnet, and
• the upstream magnet section that is secured to the arm side and that switches between a closed state in which the needle thread is pinched and gripped between the upstream first plate-like section and the upstream second plate-like section by means of attracting the upstream first plate-like section from a back side of the upstream second plate-like section by magnetic force and an open state in which the needle thread is released from the gripped state by canceling attraction caused by magnetic force;
• the downstream grip section that is placed at a downstream position along a needle thread path of the upstream grip section and that has
• the downstream grip section main body which is placed below the upstream grip section main body on a front side of the plate section, which pinches to thereby grip the needle thread, and which has downstream first plate-like sections which is formed from a magnetic substance that is a material attracted by the magnet and provided for respective needle bars and a downstream second plate-like section which is provided at back side of the downstream first plate-like sections and on a front side of the second opening section and formed from a non-magnetic substance unattracted by the magnet, and
• the downstream magnet section that is secured to the arm side and that switches between a closed state in which the needle thread is pinches to thereby grip between the downstream first plate-like section and the downstream second plate-like section by means of attracting the downstream first plate-like section from a back side of the downstream second plate-like section by magnetic force and an open state in which the needle thread is released from a gripped state by canceling attraction caused by the magnetic force;
• needle thread supporting members that each is provided in the plate section and that each supports the needle thread in its horizontal direction at the position of the first opening section;
• the turning section that turns the needle thread existing between the upstream grip section main body and the downstream grip section main body and that has the turning arm which contacts the needle thread supported by the needle thread supporting member and a needle thread motor which is secured to the arm side and which turns 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 in accordance with torque data which are generated from embroidery data and whose torque value is specified for each stitch, while the upstream grip section main body is closed and while the downstream grip section main body is opened, thereby imparting rotating force to the turning arm in an upward direction 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 detects at a starting point of the position control zone a current angle position of the needle thread motor which is a rotational position of the needle thread motor, generates angle correspondence data which specify an angle of the needle thread motor from the current angle position to an initial angle position of the needle thread motor for each angle of a main spindle motor representing a rotational position of the main spindle motor which rotates a main spindle for transmitting power to the thread take-up levers and the needle bars, controls a position of the needle thread motor to its angle of the needle thread motor corresponding to the angle of the main spindle motor as the angle of the main spindle motor changes as a result of rotation of the main spindle motor in such a way that the angle of the needle thread motor returns to an initial angle position of the needle thread motor, to thus impart rotating force to the turning arm in an upward direction and draw a needle thread from an upstream position, turns the turning arm downward so as to recede to a receded position and slides the needle bar housing case when a needle thread to be selected is changed on occasion of processing proceeding to control a next stitch, thereby letting the upstream magnet section, the downstream magnet section, and the turning arm come to a position of the selected needle thread.