A rotary hook (1) of a lockstitch sewing machine composed of at least one hook body (2) includes a cylindrical cavity (11) and a basket (6, 6b) free to rotate in the cylindrical cavity (11), a bobbin case (8, 8b) housed in the basket (6, 6b) and a bobbin (4, 4b) housed in the bobbin case (8, 8b), elements (30, 40, 50, 60, 61, 70,) suited to create a friction between the bobbin case (8, 8b) and the basket (6, 6b), so as to prevent the bobbin case (8, 8b) to move freely and to vibrate within the plays present between the bobbin case (8, 8b) and the basket (6, 6b) and to consequently reduce the noisiness created during the sewing operation.

A rotary hook (1) of a lockstitch sewing machine composed of at least one hook body (2) includes a cylindrical cavity (11) and a basket (6, 6b) free to rotate in the cylindrical cavity (11), a bobbin case (8, 8b) housed in the basket (6, 6b) and a bobbin (4, 4b) housed in the bobbin case (8, 8b), elements (30, 40, 50, 60, 61, 70,) suited to create a friction between the bobbin case (8, 8b) and the basket (6, 6b), so as to prevent the bobbin case (8, 8b) to move freely and to vibrate within the plays present between the bobbin case (8, 8b) and the basket (6, 6b) and to consequently reduce the noisiness created during the sewing operation.

Hook for lockstitch sewing machine, both of the rotary type and of the Central Bobbin type (CB-shuttle or CB-hook), which includes a bobbin case (508, 708, 808, 908, 1008, 1108, 1208) with an improved slide, composed of multiple components, including a slide body (515a, 615a, 715a, 815a, 915a, 1115a, 1215a) which performs entirely the functions of guiding the slide on the bobbin case and of creation of the leverage with the lever (16, 16b), and at least one secondary component (582, 782, 882, 982, 1182, 1286), fixed to the slide body and apt to perform the function of slide's claw or guide and/or protection of the thread.

Hook for lockstitch sewing machine, both of the rotary type and of the Central Bobbin type (CB-shuttle or CB-hook), which includes a bobbin case (508, 708, 808, 908, 1008, 1108, 1208) with an improved slide, composed of multiple components, including a slide body (515a, 615a, 715a, 815a, 915a, 1115a, 1215a) which performs entirely the functions of guiding the slide on the bobbin case and of creation of the leverage with the lever (16, 16b), and at least one secondary component (582, 782, 882, 982, 1182, 1286), fixed to the slide body and apt to perform the function of slide's claw or guide and/or protection of the thread.

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.

Provided is a double-needle lockstitch sewing machine that can easily sew a fabric rolled into a tubular shape by two rows of lockstitch. The double-needle lockstitch sewing machine includes: a pair of needles (9) that reciprocates in an up-down direction; a pair of loop catchers (40) that is arranged respectively corresponding to the pair of needles (9) and that catch loops of needle threads formed by the needles (9) by rotating about hook shafts (41) extending in the up-down direction; a lower shaft (20) that is disposed in front of the needles (9) and the loop catchers (40) in the cloth feeding direction and extends in the left-right direction and that rotates in conjunction with a main shaft (10) that drives the needles (9); and connecting shafts (30) that extend in the cloth feeding direction and are connected to the lower shaft (20) and the hook shafts (41) in a power transmittable manner to rotate. The loop catchers (40) are rotationally driven in conjunction with an up and down movement of the needles (9) as a rotational power of the lower shaft (20) is transmitted to the hook shafts (41) via the connecting shafts (30). Thus, it is possible to easily sew a tubular article with two rows of lockstitch seams.

The present invention relates to a rotary shuttle for a sewing machine, wherein a shuttle tension spring having a lower thread separation-prevention end for facilitating threading the lower thread (A) supplied from the center is coupled to the outer circumferential edge of a lower thread case (30).

The present invention relates to a rotary shuttle for a sewing machine, wherein a shuttle tension spring having a lower thread separation-prevention end for facilitating threading the lower thread (A) supplied from the center is coupled to the outer circumferential edge of a lower thread case (30).

Provided is a double-needle lockstitch sewing machine that can easily sew a fabric rolled into a tubular shape by two rows of lockstitch. The double-needle lockstitch sewing machine includes: a pair of needles (9) that reciprocates in an up-down direction; a pair of loop catchers (40) that is arranged respectively corresponding to the pair of needles (9) and that catch loops of needle threads formed by the needles (9) by rotating about hook shafts (41) extending in the up-down direction; a lower shaft (20) that is disposed in front of the needles (9) and the loop catchers (40) in the cloth feeding direction and extends in the left-right direction and that rotates in conjunction with a main shaft (10) that drives the needles (9); and connecting shafts (30) that extend in the cloth feeding direction and are connected to the lower shaft (20) and the hook shafts (41) in a power transmittable manner to rotate. The loop catchers (40) are rotationally driven in conjunction with an up and down movement of the needles (9) as a rotational power of the lower shaft (20) is transmitted to the hook shafts (41) via the connecting shafts (30). Thus, it is possible to easily sew a tubular article with two rows of lockstitch seams.

Embroidery and sewing machines can utilize rotary hooks to attach thread to materials. An adhesive joint configured to sever if the rotary hook becomes jammed prevents damage to the rest of the drive system. The severable joint is located between a sleeve and a drive shaft nearest the rotary hook to allow for easy removal and repair of the joint.