Abstract: A sewing machine moves a presser foot up and down through a presser-bar lifting lever to depress a cloth. The lever is moved down by a stepping motor at a constant move-down amount. A compression spring is present between the stepping motor and the presser foot. The compression spring is compressed by some of the constant move-down amount of the lever, and applies, to the presser foot, pushing force canceling repulsive force from the depressed cloth. The move-down amount of the presser foot is detected by an encoder, and a thickness of the cloth is calculated by a cloth-thickness calculator. The cloth-thickness calculator performs calculation based on the move-down amounts at two timings in a time period at which the presser foot depresses the cloth and attempts to further move down.

Abstract: Provided is a horizontal rotary hook including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate accommodating the permanent magnet and provided with a mounting hole at a center of a diameter thereof; a non-metallic outer rotary hook accommodating the magnet plate and having a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the hole of the magnet plate and the shaft hole of the outer rotary hook and includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A friction coefficient of a contact surface of the magnet plate that comes into contact with the outer rotary hook is set to be larger than a friction coefficient of the flange of the hook supporting shaft.

Abstract: A sewing machine includes a thread take-up lever that supplies an upper thread to a needle from a thread supply source, a hook which catches the upper thread inserted in the needle, and which intertwine the upper thread with a lower thread, and a control unit that controlling a hook release phase at which the hook releases the upper thread in such a way that a hook/upper-thread necessary amount that is necessary when the upper thread is intertwined with the lower thread becomes smaller than a thread-take-up-lever/upper-thread supply amount that is supplied by an operation of the thread take-up lever. The control unit controls the hook release phase at a plurality of timings.

Abstract: The feed dog adjustment device, includes a feed rock shaft rotatably attached to a sewing machine frame with an eccentric shaft provided at an eccentric position with respect to a center, a feed rock shaft crank that slides about the feed rock shaft, a feed bar rotatably attached to the feed rock shaft crank, a feed dog provided on the feed bar, an actuator for inclination adjustment that rotates the eccentric shaft, and a controller that drives the actuator for inclination adjustment to adjust an inclination of the feed dog on a basis of data related to a type and stretchability of fabric.

Abstract: A sewing machine translates a stitchwork frame with which a cloth is fastened along a direction of a plane where the cloth is fastened based on stitchwork data to form a stitchwork pattern. A presser foot located above the cloth has a height changed by an actuator like a stepping motor in accordance with the advancement of a stitchwork formation. Hence, a predetermined clearance between the cloth and the presser foot is maintained.

Abstract: A sewing machine includes a needle bar turning apparatus. The apparatus includes: a needle bar holder swingably held with a fulcrum point as the center of rotation; a swing rod connected to the needle bar holder to transmit a driving force that swings the needle bar holder; a needle bar held by the needle bar holder, which is slidable along the axis and turnable with the axis as the center of rotation, and swingable together with the needle bar holder; a coupling member fixed to the needle bar such that it extends in a direction orthogonal to the needle bar; a guide shaft that extends along the needle bar; and a guide shaft connecting bracket fitted to the coupling member and the guide shaft such that it is movable relative to the coupling member in the coupling member extending direction, and turnable relative to the coupling member with a vertical line extending in the extending direction as the center of rotation.

Abstract: A sewing machine includes an upper shaft rotatable so as to drive a needle bar, a lower shaft rotatable so as to drive a feed dog, an upper-shaft pulley provided for the upper shaft, a lower-shaft pulley provided for the lower shaft, a belt linking the upper-shaft pulley with the lower-shaft pulley to synchronize respective rotations, and a belt adjusting mechanism contacting the belt and changing a belt length at a tensioned side of the belt where the belt is drawn in.

Abstract: The feed dog adjustment device, includes a feed rock shaft, rotatably attached to a sewing machine frame with an eccentric shaft provided at an eccentric position with respect, to a center, a feed rock shaft crank that, slides about the feed rock shaft, a feed bar rotatably attached to the feed rock shaft, crank, a feed dog provided on the feed bar, an actuator for inclination adjustment that rotates the eccentric shaft, and a controller that drives the actuator for inclination adjustment to adjust an inclination of the feed dog on a basis of data related to a type and stretchability of fabric.

Abstract: A sewing machine includes a sewing-machine motor that drives, through an upper shaft and a lower shaft, a thread take-up lever, a needle bar, and a shuttle in conjunction one another. In addition, the sewing machine includes a stepping motor different from the sewing-machine motor. A bobbin-thread supply member is driven by drive power from the stepping motor, and applies tension to a bobbin thread in accordance with the drive timing of the stepping motor and the drive amount of the stepping motor. The drive timing of the stepping motor is variable in accordance with a sewing condition.

Abstract: A sewing machine includes an upper shaft rotatable so as to drive a needle bar, a lower shaft rotatable so as to drive a hook, an upper-shaft pulley attached to the upper shaft, a lower-shaft pulley attached to the lower shaft, a belt linking the upper-shaft pulley and the lower-shaft pulley, and synchronizing a rotation of the upper-shaft pulley and a rotation of the lower-shaft pulley with each other, a belt adjusting mechanism contacting the belt and changing a belt length at a tensioned side at which the belt is drawn, and a tensioner tensioning the belt in accordance with the change in the belt length of the belt at the tensioned side.

Abstract: A sewing machine includes a needle bar turning apparatus. The apparatus includes: a needle bar holder swingably held with a fulcrum point as the center of rotation; a swing rod connected to the needle bar holder to transmit a driving force that swings the needle bar holder; a needle bar held by the needle bar holder, which is slidable along the axis and turnable with the axis as the center of rotation, and swingable together with the needle bar holder; a coupling member fixed to the needle bar such that it extends in a direction orthogonal to the needle bar; a guide shaft that extends along the needle bar; and a guide shaft connecting bracket fitted to the coupling member and the guide shaft such that it is movable relative to the coupling member in the coupling member extending direction, and turnable relative to the coupling member with a vertical line extending in the extending direction as the center of rotation.

Abstract: A sewing machine moves a presser foot up and down through a presser-bar lifting lever to depress a cloth. The lever is moved down by a stepping motor at a constant move-down amount. A compression spring is present between the stepping motor and the presser foot. The compression spring is compressed by some of the constant move-down amount of the lever, and applies, to the presser foot, pushing force canceling repulsive force from the depressed cloth. The move-down amount of the presser foot is detected by an encoder, and a thickness of the cloth is calculated by a cloth-thickness calculator. The cloth-thickness calculator performs calculation based on the move-down amounts at two timings in a time period at which the presser foot depresses the cloth and attempts to further move down.

Abstract: A sewing machine translates a stitchwork frame with which a cloth is fastened along a direction of a plane where the cloth is fastened based on stitchwork data to form a stitchwork pattern. A presser foot located above the cloth has a height changed by an actuator like a stepping motor in accordance with the advancement of a stitchwork formation. Hence, a predetermined clearance between the cloth and the presser foot is maintained.

Abstract: A sewing machine includes an upper shaft rotatable so as to drive a needle bar, a lower shaft rotatable so as to drive a feed dog, an upper-shaft pulley provided for the upper shaft, a lower-shaft pulley provided for the lower shaft, a belt linking the upper-shaft pulley with the lower-shaft pulley to synchronize respective rotations, and a belt adjusting mechanism contacting the belt and changing a belt length at a tensioned side of the belt where the belt is drawn in.

Abstract: A sewing machine includes a sewing-machine motor that drives, through an upper shaft and a lower shaft, a thread take-up lever, a needle bar, and a shuttle in conjunction one another. In addition, the sewing machine includes a stepping motor different from the sewing-machine motor. A bobbin-thread supply member is driven by drive power from the stepping motor, and applies tension to a bobbin thread in accordance with the drive timing of the stepping motor and the drive amount of the stepping motor. The drive timing of the stepping motor is variable in accordance with a sewing condition.

Abstract: A sewing machine includes a thread take-up lever that supplies an upper thread to a needle from a thread supply source, a hook which catches the upper thread inserted in the needle, and which intertwine the upper thread with a lower thread, and a control unit that controlling a hook release phase at which the hook releases the upper thread in such a way that a hook/upper-thread necessary amount that is necessary when the upper thread is intertwined with the lower thread becomes smaller than a thread-take-up-lever/upper-thread supply amount that is supplied by an operation of the thread take-up lever. The control unit controls the hook release phase at a plurality of timings.

Abstract: Provided is a horizontal rotary hook for a sewing machine including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate that accommodates the permanent magnet and is provided with a shaft hole for mounting at a center of a diameter thereof; a non-metallic outer rotary hook that accommodates the magnet plate and has a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the shaft hole of the magnet plate and the shaft hole of the outer rotary hook, and that includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A rotation stopper for the magnet plate is disposed to be positioned more inward than an outer circumference edge of the permanent magnet placed in the magnet plate.

Abstract: A sewing machine includes an upper shaft rotatable so as to drive a needle bar, a lower shaft rotatable so as to drive a hook, an upper-shaft pulley attached to the upper shaft, a lower-shaft pulley attached to the lower shaft, a belt linking the upper-shaft pulley and the lower-shaft pulley, and synchronizing a rotation of the upper-shaft pulley and a rotation of the lower-shaft pulley with each other, a belt adjusting mechanism contacting the belt and changing a belt length at a tensioned side at which the belt is drawn, and a tensioner tensioning the belt in accordance with the change in the belt length of the belt at the tensioned side.

Abstract: Provided is a horizontal rotary hook including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate accommodating the permanent magnet and provided with a mounting hole at a center of a diameter thereof; a non-metallic outer rotary hook accommodating the magnet plate and having a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the hole of the magnet plate and the shaft hole of the outer rotary hook and includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A friction coefficient of a contact surface of the magnet plate that comes into contact with the outer rotary hook is set to be larger than a friction coefficient of the flange of the hook supporting shaft.

Abstract: Provided is a horizontal rotary hook for a sewing machine including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate that accommodates the permanent magnet and is provided with a shaft hole for mounting at a center of a diameter thereof; a non-metallic outer rotary hook that accommodates the magnet plate and has a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the shaft hole of the magnet plate and the shaft hole of the outer rotary hook, and that includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A rotation stopper for the magnet plate is disposed to be positioned more inward than an outer circumference edge of the permanent magnet placed in the magnet plate.