A rotary hook includes a bobbin case housing a lower thread bobbin, an inner rotary hook and an outer rotary hook. A needle drop hole is provided in an upper front surface of the inner rotary hook, and a recess is formed therein at a position deviated from the needle drop hole in a rotating direction of the outer rotary hook. The recess opens forward and upward and has a rear wall. The bobbin case provides with a thread take-up member for directing a lower thread, paid out from the lower thread bobbin, toward the recess. The lower thread paid out from the lower thread bobbin is passed through the recess via the thread take-up member and then directed to a needle hole of a needle plate provided above. With this arrangement, it is possible to structurally avoid occurrence of a hitch stitch caused by the lower thread.

A rotary hook includes a bobbin case housing a lower thread bobbin, an inner rotary hook and an outer rotary hook. A needle drop hole is provided in an upper front surface of the inner rotary hook, and a recess is formed therein at a position deviated from the needle drop hole in a rotating direction of the outer rotary hook. The recess opens forward and upward and has a rear wall. The bobbin case provides with a thread take-up member for directing a lower thread, paid out from the lower thread bobbin, toward the recess. The lower thread paid out from the lower thread bobbin is passed through the recess via the thread take-up member and then directed to a needle hole of a needle plate provided above. With this arrangement, it is possible to structurally avoid occurrence of a hitch stitch caused by the lower thread.

A needle plate has a needle hole and a guide hole communicating with the needle hole. The guide hole is located near a front side of a sewing machine and positionally deviated from an up-down movement trajectory of a sewing needle in a rotating direction of a rotary hook. The needle plate has a groove formed in front of the needle hole and extending from the guide hole in a direction opposite to the rotating direction of the rotary hook. While the groove is open upward and at its portion leading to the guide hole, the other portions of the groove are defined by a bottom surface and side walls. In a sewing operation, depending on a direction in which a member holding a sewing workpiece moves, the lower thread passes through the guide hole to be guided to the front of the needle hole via the groove.

A needle plate has a needle hole and a guide hole communicating with the needle hole. The guide hole is located near a front side of a sewing machine and positionally deviated from an up-down movement trajectory of a sewing needle in a rotating direction of a rotary hook. The needle plate has a groove formed in front of the needle hole and extending from the guide hole in a direction opposite to the rotating direction of the rotary hook. While the groove is open upward and at its portion leading to the guide hole, the other portions of the groove are defined by a bottom surface and side walls. In a sewing operation, depending on a direction in which a member holding a sewing workpiece moves, the lower thread passes through the guide hole to be guided to the front of the needle hole via the groove.

A hook and bobbin locator apparatus and method consisting of a mounting plate and more than one hook and bobbin combination. Each of the more than one hook and bobbin combinations is connected with a stepper motor and each of the more than one hook and bobbin combinations are removably connected with the mounting plate. A stepper motor is also connected with the mounting plate and a controller is connected with the mounting plate stepper motor and the hook and bobbin combination stepper motors such that movement of the mounting plate and the hook and bobbin combinations are controlled by the controller.

A hook and bobbin locator apparatus and method consisting of a mounting plate and more than one hook and bobbin combination. Each of the more than one hook and bobbin combinations is connected with a stepper motor and each of the more than one hook and bobbin combinations are removably connected with the mounting plate. A stepper motor is also connected with the mounting plate and a controller is connected with the mounting plate stepper motor and the hook and bobbin combination stepper motors such that movement of the mounting plate and the hook and bobbin combinations are controlled by the controller.

In an automated bobbin-exchanger device (3), a guide groove (6) which is provided on a vertical transfer base (5) has a horizontal portion (6a), a vertical portion (6c) and an arcuate portion (6b). A bobbin chuck (18) reciprocally moves pivotably along the guide groove (6) to make a travel distance minimum, thus enabling users to quickly exchange the bobbin case (12). By placing a bobbin holder (13a), a chuck-drive lever (14) and a chuck-drive air-cylinder (26) circumferentially, it is possible to make a whole structure compact and space-saving. The bobbin-exchanger device (3) requires only two bobbin cases (12) available to make their check and maintenance easy.

In an automated bobbin-exchanger device (3), a guide groove (6) which is provided on a vertical transfer base (5) has a horizontal portion (6a), a vertical portion (6c) and an arcuate portion (6b). A bobbin chuck (18) reciprocally moves pivotably along the guide groove (6) to make a travel distance minimum, thus enabling users to quickly exchange the bobbin case (12). By placing a bobbin holder (13a), a chuck-drive lever (14) and a chuck-drive air-cylinder (26) circumferentially, it is possible to make a whole structure compact and space-saving. The bobbin-exchanger device (3) requires only two bobbin cases (12) available to make their check and maintenance easy.

A bobbin holder that grasps a holder body and a flange of a bobbin that winds a thread n around the holder body, the holder including: an opening formed in an upper surface of the holder body; a thread holding portion that holds a thread n and is arranged in the opening so as to protrude from a center of the holder body toward an outer circumference of the holder body; and a cutting blade that cuts the thread held by the thread holding portion, the blade being disposed in one of regions inside the opening that is partitioned by the thread holding portion, wherein the cutting blade is disposed on a thread path of the thread n being pulled after the thread n, which is wound around the bobbin grasped by a grasping portion and is pulled from the other region inside the partitioned opening, is held by the thread holding portion.

A rotary hook includes a bobbin case housing a lower thread bobbin, an inner rotary hook and an outer rotary hook. A needle drop hole is provided in an upper front surface of the inner rotary hook, and a recess is formed therein at a position deviated from the needle drop hole in a rotating direction of the outer rotary hook. The recess opens forward and upward and has a rear wall. The bobbin case provides with a thread take-up member for directing a lower thread, paid out from the lower thread bobbin, toward the recess. The lower thread paid out from the lower thread bobbin is passed through the recess via the thread take-up member and then directed to a needle hole of a needle plate provided above. With this arrangement, it is possible to structurally avoid occurrence of a hitch stitch caused by the lower thread.