Disclosed herein are a lower-thread supply device of sewing machine and a sewing method. The device includes a bobbin case (300) having an outlet (330) from which lower thread is drawn out, and a needle through-hole (340) through which a needle (600) moving downwards with upper thread (a) being fitted passes, and a hook body (200) in which the bobbin case (300) is mounted, the hook body being installed to be rotatable by a power device of a sewing machine, guiding upper thread (a2) on a sewn fabric side to a front area of the bobbin case (300) while catching and dragging the upper thread (a) via a hook (210), and guiding upper thread (a1) on a spool side to a rear area of the bobbin case (300). The bobbin case (300) is installed not to be rotated when the hook body (200) rotates.

Disclosed herein are a lower-thread supply device of sewing machine and a sewing method. The device includes a bobbin case (300) having an outlet (330) from which lower thread is drawn out, and a needle through-hole (340) through which a needle (600) moving downwards with upper thread (a) being fitted passes, and a hook body (200) in which the bobbin case (300) is mounted, the hook body being installed to be rotatable by a power device of a sewing machine, guiding upper thread (a2) on a sewn fabric side to a front area of the bobbin case (300) while catching and dragging the upper thread (a) via a hook (210), and guiding upper thread (a1) on a spool side to a rear area of the bobbin case (300). The bobbin case (300) is installed not to be rotated when the hook body (200) rotates.

A sewing machine includes at least one needle bar, a threading motor, a threading mechanism, a processor, and a memory. The threading mechanism is configured to pass an upper thread through an eye of a sewing needle. The memory is configured to store computer-readable instructions that, when executed by the processor, instruct the processor to perform processes. The processes include making one of a setting that prohibits operation of the threading mechanism and a setting that does not prohibit the operation of the threading mechanism. The processes include switching the operation of the threading mechanism by prohibiting the operation of the threading mechanism in a case where the setting that prohibits the operation of the threading mechanism is made, and permitting the operation of the threading mechanism in a case where the setting that does not prohibit the operation of the threading mechanism is made.

A sewing machine includes at least one needle bar, a threading motor, a threading mechanism, a processor, and a memory. The threading mechanism is configured to pass an upper thread through an eye of a sewing needle. The memory is configured to store computer-readable instructions that, when executed by the processor, instruct the processor to perform processes. The processes include making one of a setting that prohibits operation of the threading mechanism and a setting that does not prohibit the operation of the threading mechanism. The processes include switching the operation of the threading mechanism by prohibiting the operation of the threading mechanism in a case where the setting that prohibits the operation of the threading mechanism is made, and permitting the operation of the threading mechanism in a case where the setting that does not prohibit the operation of the threading mechanism is made.

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 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.