Nsd Corporation

Tokai Kogyo Mishin Kabushiki Kaisha

Tism Co., Ltd

Masayoshi Ono

Yoshichika Takizawa

Hirotsugu Uenishi

Tatsuhiro Kurashima

Isao Ohashi

Mitsuhiro Fujiura

Koichi Nakamura

Disclosed is a sewing machine which evaluates sewing quality using a stitch tightness index. During sewing operation, a used length of an upper thread per stitch is detected, and a stitch tightness index per sewn stitch is calculated on the basis of a stitch length per stitch defined by sewing pattern data, a fabric thickness of a sewing workpiece, and detected data of the used length of the upper thread. Then, notification is made which corresponds to the calculated stitch tightness index per sewn stitch (such as a visual display of the stitch tightness index). After that, acceptability/non-acceptability of the thread tightness per sewn stitch can be determined by comparing the calculated stitch tightness index per sewn stitch against a reference value, and a result of the determination can be notified.

Sewing quality control in sewing machine

A presser footof a sewing machine is provided with a main body, a swayingly reciprocating mechanism section, and a thread hooking rod drive motor. The swayingly reciprocating mechanism sectionhas a thread hooking rod, and a needle thread receiving section for fixing a needle thread together with the thread hooking rodis provided inside a leading-end structure sectionof the main body. As a result of driving of the thread hooking rod drive motor, the swayingly reciprocating mechanism sectionreciprocally moves while swaying with respect to the main body. When a thread take-up lever pulls up the needle thread, a circular movement arm which performs rotation movement while hooking the needle thread adjusts a rotational angle of the circular movement arm, thereby enabling adjustment of a length of a needle thread in one preceding stitch.

Sewing machine

To provide a sewing machine that can control tension on a needle thread and tension on a bobbin thread on a per-stitch basis; that enables even heads of a multi-head embroidery sewing machine to form an identical embroidery; and that enables even a plurality of sewing machines to form identical embroidery. A memory device stores for each stitch of embroidery data a needle thread control torque value and a bobbin thread control torque value. In a needle thread torque control zone, an upstream grip section main body is closed, and a downstream grip section main body is opened. A needle thread motor is subjected to torque control in accordance with the needle thread control torque value. In the meantime, in a position control zone, the upstream grip section body is opened, and the downstream grip section body is closed, thereby subjecting the needle thread motor to position control.

There is provided a needle thread tension controller that can control a magnitude of tension on a needle thread for each stitch, that can draw the needle thread with a slim chance of occurrence of a thread break, that easily, accurately detects occurrence of the thread break when the thread break has occurred, and that does not cause any excess or deficiency of a quantity of accumulated thread, which would otherwise be caused by drawing a needle thread. There are provided an upstream grip sectionand a downstream grip sectionfor gripping a needle thread and a turning sectionfor turning the needle thread. In a torque control zone, rotating force is imparted to a turning arm in accordance with a torque value.

There is provided a sewing-machine bobbin thread tension controller capable of elaborately, accurately controlling bobbin thread tension without depending on frictional force. A bobbin thread tension controller includes an outer shuttle, a middle shuttle presser, a middle shuttle, a bobbin thread tension control mechanism, a shuttle actuation unit, and a bobbin. The middle shuttle has a magnet. A magnet is disposed, in close proximity to the magnet, on an arm attached to a rotary shaft of a shuttle actuation motor provided in the shuttle actuation unit. The middle shuttle is rotated by rotating the magnet by means of the motor. Further, a rotary disc is provided, in close proximity to the middle shuttle, on a rotary shaft of a bobbin thread tension control motor of the bobbin thread tension control mechanism and is provided with a magnet. A magnet is disposed on a part of the bobbin facing the rotary disc.

Growing community of inventors

Nagoya, Japan

Masayoshi Ono