In the large-diameter bobbin mode of the bobbin winding device, the switching lever is arranged at the switching position, and the interlocking lever is rotated to the blocking position blocking the lowering of the thread trimming holder at the raised position. Therefore, the small-diameter bobbin is arranged above the regular mounting position if it is mounted on the spool shaft. Thus, the engaging hook of the bobbin stopper does not engage with the upper end portion of the core portion of the small-diameter bobbin, and the engaging hook and the thread trimming holder do not sandwich the small-diameter bobbin vertically. Therefore, when the spool shaft is rotated by the spool motor in this state, the bobbin thread is not wound around the small-diameter bobbin since it idles with respect to the spool shaft.

In the large-diameter bobbin mode of the bobbin winding device, the switching lever is arranged at the switching position, and the interlocking lever is rotated to the blocking position blocking the lowering of the thread trimming holder at the raised position. Therefore, the small-diameter bobbin is arranged above the regular mounting position if it is mounted on the spool shaft. Thus, the engaging hook of the bobbin stopper does not engage with the upper end portion of the core portion of the small-diameter bobbin, and the engaging hook and the thread trimming holder do not sandwich the small-diameter bobbin vertically. Therefore, when the spool shaft is rotated by the spool motor in this state, the bobbin thread is not wound around the small-diameter bobbin since it idles with respect to the spool shaft.

In the large-diameter bobbin mode of the bobbin winding device, the switching lever is arranged at the switching position, and the interlocking lever is rotated to the blocking position blocking the lowering of the thread trimming holder at the raised position. Therefore, the small-diameter bobbin is arranged above the regular mounting position if it is mounted on the spool shaft. Thus, the engaging hook of the bobbin stopper does not engage with the upper end portion of the core portion of the small-diameter bobbin, and the engaging hook and the thread trimming holder do not sandwich the small-diameter bobbin vertically. Therefore, when the spool shaft is rotated by the spool motor in this state, the bobbin thread is not wound around the small-diameter bobbin since it idles with respect to the spool shaft.

In the large-diameter bobbin mode of the bobbin winding device, the switching lever is arranged at the switching position, and the interlocking lever is rotated to the blocking position blocking the lowering of the thread trimming holder at the raised position. Therefore, the small-diameter bobbin is arranged above the regular mounting position if it is mounted on the spool shaft. Thus, the engaging hook of the bobbin stopper does not engage with the upper end portion of the core portion of the small-diameter bobbin, and the engaging hook and the thread trimming holder do not sandwich the small-diameter bobbin vertically. Therefore, when the spool shaft is rotated by the spool motor in this state, the bobbin thread is not wound around the small-diameter bobbin since it idles with respect to the spool shaft.

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.