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: 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: 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: In a sewing machine having an automatic thread cutting mechanism, a situation of a thread cutting operation is detected in power-OFF to continuously carry out a proper operation when a power supply is turned ON again after sudden power-OFF. In a sewing machine having an automatic thread cutting mechanism, there is provided means for detecting an operation situation of the automatic thread cutting mechanism when a power supply is turned ON. Based on a signal for the detection, the automatic thread cutting mechanism is operated to complete a thread cutting operation and to carry out a control to return into an initial state when a stop is performed with the thread cutting mechanism in power-ON executing the thread cutting work.

Abstract: Disclosed is an automatic thread cutting device for a sewing machine which is provided with a horizontal loop taker, wherein a thread catching member (4) is operated in response to a thread cutting instruction to reciprocatingly move with a movable blade (5) along a predetermined course, the thread catching member (4) normally catching the upper thread when moving in the return-way of reciprocation to guide the upper thread to a fixed blade (14) which is provided to cut the upper thread in cooperation with the movable blade (5), and wherein a thread regulating means is provided to cut the lower thread (29d) together with the upper thread, the thread regulating means being operated to press down the lower thread (29d) to a position where the lower thread (29d) is caught by the thread catching member (4) in addition to the upper thread when the thread catching member (4) is moving in the return-way of reciprocation.

Abstract: A free work pressing device for a sewing machine includes a holding portion for mounting the free work pressing device to the presser bar of sewing machine, a slide shaft supported by the holding portion and being slidingly movable in the axial direction, a work pressing foot secured to the lower end of the slide shaft, an elastic member for normally pressing the slide shaft axially in the downward direction relative to the holding portion, an adjust mechanism for adjusting the vertical position of the work pressing foot relative to the work which is to be stitched. The work pressing foot is smoothly movable as yielding up and down in dependence upon a variation in the thickness of the work against and under control of the elastic member.

Abstract: Disclosed is an automatic thread cutting device for a sewing machine which is provided with a horizontal loop taker, wherein a thread catching member 4 is operated in response to a thread cutting instruction to reciprocatingly move with a movable blade 5 along a predetermined course, the thread catching member 4 normally catching the upper thread when moving in the return-way of reciprocation to guide the upper thread to a fixed blade 14 which is provided to cut the upper thread in cooperation with the movable blade 5, and wherein a thread regulating means is provided to cut the lower thread 29d together with the upper thread, the thread regulating means being operated to press down the lower thread 29d to a position where the lower thread 29d is caught by the thread catching member 4 in addition to the upper thread when the thread catching member 4 is moving in the return-way of reciprocation.

Abstract: Disclosed is a free work pressing device for sewing machine which is simple in structure and smooth in operation. As to the variation in the thickness of the work (18), the work pressing foot (C) is smoothly movable as yielding up and down in dependence upon the variation in the thickness of the work against and under the control of the elastic member (14). The free work pressing device sewing machine comprises a holding portion (A) for mounting the free work pressing device to the presser bar (16) of sewing machine, a slide shaft (5) supported by the holding portion (A) and being slidingly movable in the axial direction, a work pressing foot (C) secured to the lower end of the slide shaft (5), an elastic member (14) for normally pressing the slide shaft (5) axially in the downward direction relative to the holding portion (A), an adjust mechanism (B) for adjusting the vertical position of the work pressing foot (C) relative to the work (18) which is to be stitched.

Abstract: In a sewing machine having an automatic thread cutting mechanism, a situation of a thread cutting operation is detected in power-OFF to continuously carry out a proper operation when a power supply is turned ON again after sudden power-OFF. In a sewing machine having an automatic thread cutting mechanism, there is provided means for detecting an operation situation of the automatic thread cutting mechanism when a power supply is turned ON. Based on a signal for the detection, the automatic thread cutting mechanism is operated to complete a thread cutting operation and to carry out a control to return into an initial state when a stop is performed with the thread cutting mechanism in power-ON executing the thread cutting work.

Abstract: A sewing machine has a drive mechanism for driving an embroidering frame B, means for holding the embroidering frame B and operatively connected to the drive mechanism to be driven thereby to move the embroidering frame B in X-Y direction relative to a vertically reciprocating needle on the surface of a machine bed, and means for normally pressing the embroidering frame B against the surface of the machine bed with an optimal force to absorb the vibrations of the embroidering frame B which may be caused during embroidery stitching operation.

Abstract: A sewing machine having an embroidery stitching function is disclosed, the sewing machine comprising a drive mechanism for driving an embroidering frame B, a means for holding the embroidering frame B and operatively connected to the drive mechanism to be driven thereby to move the embroidering frame B in X-Y direction relative to a vertically reciprocating needle on the surface of a machine bed, and a means for normally pressing the embroidering frame B against the surface of the machine bed with an optimal force to absorb the vibrations of the embroidering frame B which may be caused during embroidery stitching operation, thereby to prevent the embroidering frame B from vibration and/or moving fup from the surface of the machine bed to secure a stabilized embroidery stitching operation.