A method for automatically piecing a thread at a workstation of a textile machine, includes seeking an end of the thread on a surface of a bobbin with a suction nozzle and unwinding the thread from the bobbin counter to a regular draw-off direction of the thread and sucking the thread into the suction nozzle. The bobbin is driven in a direction of reverse rotation with a drive. A thread loop is draw-opened in the thread and moved towards a piecing unit via movement of a feeder unit. The bobbin is driven in the direction of reverse rotation during the drawing-open of the thread loop such that the thread is unwound from the bobbin. A speed of reverse rotation of the bobbin is coordinated with movement of the feeder unit.

A method for automatically piecing a thread at a workstation of a textile machine, includes seeking an end of the thread on a surface of a bobbin with a suction nozzle and unwinding the thread from the bobbin counter to a regular draw-off direction of the thread and sucking the thread into the suction nozzle. The bobbin is driven in a direction of reverse rotation with a drive. A thread loop is draw-opened in the thread and moved towards a piecing unit via movement of a feeder unit. The bobbin is driven in the direction of reverse rotation during the drawing-open of the thread loop such that the thread is unwound from the bobbin. A speed of reverse rotation of the bobbin is coordinated with movement of the feeder unit.

Hook (11, 12, 13, 14) for a lockstitch sewing machine, or parts of the hook such as the support element of the tension spring (in particular the basket or the bobbin case) or the tension spring itself, including a tension spring (80, 90, 100, 110, 120) that includes a bending towards the outside (with respect to the support element on which it is mounted and with respect to the main bending radius of the tension spring) of the tension spring's extremity designed to press on the bobbin thread, so that the pressure point (P) on the bobbin thread is the point of tangency between the bending radius (R) of the bending of the tension spring's extremity and the support element of the tension spring, so as to generate a stable tension of the bobbin thread.

Hook (11, 12, 13, 14) for a lockstitch sewing machine, or parts of the hook such as the support element of the tension spring (in particular the basket or the bobbin case) or the tension spring itself, including a tension spring (80, 90, 100, 110, 120) that includes a bending towards the outside (with respect to the support element on which it is mounted and with respect to the main bending radius of the tension spring) of the tension spring's extremity designed to press on the bobbin thread, so that the pressure point (P) on the bobbin thread is the point of tangency between the bending radius (R) of the bending of the tension spring's extremity and the support element of the tension spring, so as to generate a stable tension of the bobbin thread.

Provided is a horizontal rotary hook including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate accommodating the permanent magnet and provided with a mounting hole at a center of a diameter thereof; a non-metallic outer rotary hook accommodating the magnet plate and having a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the hole of the magnet plate and the shaft hole of the outer rotary hook and includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A friction coefficient of a contact surface of the magnet plate that comes into contact with the outer rotary hook is set to be larger than a friction coefficient of the flange of the hook supporting shaft.

Provided is a horizontal rotary hook including: an inner rotary hook including an attracted member made of metal in an outer lower surface portion; a permanent magnet that attracts the inner rotary hook; a magnet plate accommodating the permanent magnet and provided with a mounting hole at a center of a diameter thereof; a non-metallic outer rotary hook accommodating the magnet plate and having a shaft hole at a center of a diameter of an inner bottom portion thereof; and a hook supporting shaft that is inserted through the hole of the magnet plate and the shaft hole of the outer rotary hook and includes, at an upper end thereof, a flange for rotatably supporting the outer rotary hook and the magnet plate. A friction coefficient of a contact surface of the magnet plate that comes into contact with the outer rotary hook is set to be larger than a friction coefficient of the flange of the hook supporting shaft.

The present invention relates to an under-thread supply device for a sewing machine, and more particularly, to an enhanced under-thread supply device for a sewing machine, in which the device of the present invention and a unit for mounting said device are just partially changed so as to increase the winding amount of the under-thread of conventional sewing machines in order to achieve improved efficiency of sewing and efficiently reduce the puckering of a work piece without causing changes in the basic structure of conventional sewing machines.

The present invention relates to an under-thread supply device for a sewing machine, and more particularly, to an enhanced under-thread supply device for a sewing machine, in which the device of the present invention and a unit for mounting said device are just partially changed so as to increase the winding amount of the under-thread of conventional sewing machines in order to achieve improved efficiency of sewing and efficiently reduce the puckering of a work piece without causing changes in the basic structure of conventional sewing machines.

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.