The present invention relates to a structure for fastening composite structures, and more particularly, to a sewing machine for stitching composite materials which is capable of automatically and continuously stitching the composite structures by using a high-rigidity fiber in order to laminate and join the composite materials. The sewing machine for stitching composite materials according to the present invention automatically and continuously performs a stitching operation for joining composite materials by using a high-rigidity composite fiber for joining the composite materials, and as a result, it is possible to reduce process time for joining the composite materials and improve productivity.

A system and methods for stitching are disclosed. The system includes a first thread feeding mechanism configured to feed a continuous supply of a first thread, a second thread feeding mechanism configured to feed a continuous supply of a second thread, a plate separating the first thread feeding mechanism and the second thread feeding mechanism, and a knot tying mechanism configured to pass a bight of the first thread for at least one turn around a portion of the second thread and securing the bight around the second thread.

A system and methods for stitching are disclosed. The system includes a first thread feeding mechanism configured to feed a continuous supply of a first thread, a second thread feeding mechanism configured to feed a continuous supply of a second thread, a plate separating the first thread feeding mechanism and the second thread feeding mechanism, and a knot tying mechanism configured to pass a bight of the first thread for at least one turn around a portion of the second thread and securing the bight around the second thread.

A sewing machine includes a cutting mechanism, a picker, and a drive portion. The cutting mechanism, which cuts an upper thread and a lower thread, is provided close to a shuttle that supplies the lower thread. The picker is provided such that it is able to move between an operating position and a non-operating position. The operating position is a position of the picker where the picker is proximate to the shuttle. The non-operating position is a position of the picker farther away from the shuttle than the operating position. The picker holds the upper thread in the operating position. The drive portion is provided as a common drive source for a cutting operation by the cutting mechanism and for movement of the picker.

A sewing machine includes a cutting mechanism, a picker, and a drive portion. The cutting mechanism, which cuts an upper thread and a lower thread, is provided close to a shuttle that supplies the lower thread. The picker is provided such that it is able to move between an operating position and a non-operating position. The operating position is a position of the picker where the picker is proximate to the shuttle. The non-operating position is a position of the picker farther away from the shuttle than the operating position. The picker holds the upper thread in the operating position. The drive portion is provided as a common drive source for a cutting operation by the cutting mechanism and for movement of the picker.

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 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 method for preventing seam ravel of multi-thread chain stitches is provided. After normal sewing is terminated with a looper set in a forward movement state, a state in which a needle thread loop caught by the looper is subjected to position-holding at a position closer to a forward movement end of the looper than a descent position of a needle is maintained until the needle descends through the needle thread loop caught by the looper. Thereafter, the position-holding of the needle thread loop is released to permit a sewing action for at least one stitch, thereby allowing the needle thread loop to be self-looped with a needle thread held by the needle. This surely strongly prevents the seam ravel of multi-thread chain stitches formed by the single needle, irrespective of the dimension of tension applied to the needle thread and the looper thread.

A method for preventing seam ravel of multi-thread chain stitches is provided. After normal sewing is terminated with a looper set in a forward movement state, a state in which a needle thread loop caught by the looper is subjected to position-holding at a position closer to a forward movement end of the looper than a descent position of a needle is maintained until the needle descends through the needle thread loop caught by the looper. Thereafter, the position-holding of the needle thread loop is released to permit a sewing action for at least one stitch, thereby allowing the needle thread loop to be self-looped with a needle thread held by the needle. This surely strongly prevents the seam ravel of multi-thread chain stitches formed by the single needle, irrespective of the dimension of tension applied to the needle thread and the looper thread.

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.