A device and the method for influencing the position of the knot (31) between the upper thread (23) and the lower thread (17) when sewing with a sewing machine (1) using a computer (37), which calculates for every sewing stitch to be formed a control value for an actuator (39), by which a braking force of the thread tension regulator (23) is controlled.

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.

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.

A thread inserting device includes a guide pin having a thread capture portion at its tip for capturing a thread; a holder that fixedly holds the guide pin; a main body (first and second main bodies) slidably mounting the holder; and a thread cutting portion provided to the main body for cutting the thread to a length equal to or smaller than the protrusion of the thread capture portion from a thread captured position on a thread tip 6a side after the thread is captured by the thread capture portion. By shifting the holder, the thread capture portion is protruded to a predetermined length from the main body, and the thread cut to a predetermined length by the thread cutting portion is inserted into the thread inserting hole.

The present invention provides a sewing machine that can actuary detect a physical amount of a movement of a fabric without depending on an estimated value. Thus, thread tension can be precisely adjusted. A sewing machine 1 includes a spherical body 22a exposed partly from a needle plate 2. The spherical body 22a is rotated following a feed of a fabric 100. The rotation of the spherical body 22a is detected by rotary encoders 22c, 22d. A physical amount of the movement of the fabric 100 is calculated based on a detection result of the rotary encoders 22c, 22d. The physical amount of the movement of the fabric 100 is, for example, a moving amount and a moving speed.

A bobbin includes a bobbin main body including flanges at both ends of a bobbin winder spindle for winding the bobbin thread and an outer flange attached to one of the flanges (a second flange) of the bobbin main body. A gap in which a thread end of the bobbin thread is housed is provided between the outer flange and the flange of the bobbin main body.

A sewing apparatus for applying a stitch of thread to a piece of fabric is provided. The apparatus housing includes a platform for supporting a piece of fabric, and contains a grasping member that is moved to grasp and release a thread segment fed through the housing by a needle holder. The needle holder is positioned to hold a needle that has a needle aperture for pass-through, therethrough of the thread segment, and is movable between a withdrawn position, and an advanced position in which the needle holder drives the needle through the piece of fabric to bring the thread segment into position for grasping by the grasping member. The sewing apparatus also including a needle holder driver for driving the movement of the needle holder and a thread puller for pulling the thread segment to an exterior of the housing for a user to cut.

A sewing apparatus for applying a stitch of thread to a piece of fabric is provided. The apparatus housing includes a platform for supporting a piece of fabric, and contains a grasping member that is moved to grasp and release a thread segment fed through the housing by a needle holder. The needle holder is positioned to hold a needle that has a needle aperture for pass-through, therethrough of the thread segment, and is movable between a withdrawn position, and an advanced position in which the needle holder drives the needle through the piece of fabric to bring the thread segment into position for grasping by the grasping member. The sewing apparatus also including a needle holder driver for driving the movement of the needle holder and a thread puller for pulling the thread segment to an exterior of the housing for a user to cut.