Bobbin changer apparatus for sewing machine

A sewing machine for performing sewing with an upper thread passed through a sewing needle and a lower thread paid out from a bobbin mounted in a rotary book, said sewing machine comprising:

• a bobbin stock section holding at least two bobbin cases containing lower threads of different characteristics, said bobbin stock section positioning a selected one of the bobbin cases at a predetermined bobbin changing position;
• a bobbin grasping device having a chuck section for grasping a bobbin case;
• a transfer mechanism for transferring said bobbin grasping device between the bobbin stock section and the rotary hook;
• and
• a lower thread change control section that, in response to a lower thread change signal, performs control such that a bobbin case is taken out from the rotary hook by said bobbin grasping device, said bobbin grasping device with the bobbin case taken out from the rotary hook is transferred, by said transfer mechanism, to said bobbin stock section, a new bobbin case is positioned at the predetermined bobbin changing position of said bobbin stock section, the new bobbin case is grasped by said bobbin grasping device and then said bobbin grasping device with the new bobbin case grasped thereby is transferred, by said transfer mechanism, to the rotary hook;
• wherein said bobbin stock section includes:
• a bobbin holder unit having a plurality of bobbin holding portions each provided for holding a bobbin case, said plurality of bobbin holding portions being arranged along a linear direction;
• and a mechanism for linearly driving said bobbin holder unit to position one of the bobbin holding portions at the predetermined bobbin changing position.

A sewing machine for performing sewing with an upper thread passed through a sewing needle and a lower thread paid out from a bobbin mounted in a rotary book, said sewing machine comprising:

• a bobbin stock section holding at least two bobbin cases containing lower threads of different characteristics, said bobbin stock section positioning a selected one of the bobbin cases at a predetermined bobbin changing position;
• a bobbin grasping device having a chuck section for grasping a bobbin case;
• a transfer mechanism for transferring said bobbin grasping device between the bobbin stock section and the rotary hook;
• and
• a lower thread change control section that, in response to a lower thread change signal, performs control such that a bobbin case is taken out from the rotary hook by said bobbin grasping device, said bobbin grasping device with the bobbin case taken out from the rotary hook is transferred, by said transfer mechanism, to said bobbin stock section, a new bobbin case is positioned at the predetermined bobbin changing position of said bobbin stock section, the new bobbin case is grasped by said bobbin grasping device and then said bobbin grasping device with the new bobbin case grasped thereby is transferred, by said transfer mechanism, to the rotary hook;
• wherein said bobbin stock section includes:
• a bobbin holder unit having a plurality of bobbin holding portions each provided for holding a bobbin case, said plurality of bobbin holding portions being arranged along not only a linear direction but also a rotational direction;
• and a mechanism for linearly and rotationally driving said bobbin holder unit to position one of the bobbin holding portions at the predetermined bobbin changing position.