Abstract: A low-cost sewing machine capable of achieving a desired balance between needle thread consumption and bobbin thread consumption is described. A memory section stores needle thread requirement data having precorrected needle thread requirement and postcorrected needle thread requirement. In a torque control zone, rotating force is imparted to a turning arm so as to impart a tension on the needle thread according to a torque value, while closing an upstream grip section main body and while opening a downstream grip section main body. In a first position control zone, the needle thread is drawn according to the postcorrected needle thread requirement, while opening the upstream grip section main body and while closing the downstream grip section. In a second position control zone, the turning arm is returned to an initial position, while closing the upstream grip section main body and while opening the downstream grip section main body.

Abstract: A low-cost sewing machine capable of achieving a desired balance between needle thread consumption and bobbin thread consumption is described. A memory section stores needle thread requirement data having precorrected needle thread requirement and postcorrected needle thread requirement. In a torque control zone, rotating force is imparted to a turning arm so as to impart a tension on the needle thread according to a torque value, while closing an upstream grip section main body and while opening a downstream grip section main body. In a first position control zone, the needle thread is drawn according to the postcorrected needle thread requirement, while opening the upstream grip section main body and while closing the downstream grip section. In a second position control zone, the turning arm is returned to an initial position, while closing the upstream grip section main body and while opening the downstream grip section main body.

Abstract: 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.

Abstract: A presser foot 12c of a sewing machine is provided with a main body 210, a swayingly reciprocating mechanism section 230, and a thread hooking rod drive motor 240. The swayingly reciprocating mechanism section 230 has a thread hooking rod 236, and a needle thread receiving section for fixing a needle thread together with the thread hooking rod 236 is provided inside a leading-end structure section 216 of the main body 210. As a result of driving of the thread hooking rod drive motor 240, the swayingly reciprocating mechanism section 230 reciprocally moves while swaying with respect to the main body 210. 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.

Abstract: 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.

Abstract: A presser foot 12c of a sewing machine is provided with a main body 210, a swayingly reciprocating mechanism section 230, and a thread hooking rod drive motor 240. The swayingly reciprocating mechanism section 230 has a thread hooking rod 236, and a needle thread receiving section for fixing a needle thread together with the thread hooking rod 236 is provided inside a leading-end structure section 216 of the main body 210. As a result of driving of the thread hooking rod drive motor 240, the swayingly reciprocating mechanism section 230 reciprocally moves while swaying with respect to the main body 210. 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.

Abstract: In relation to a sewing machine having a function of rotating a sewing needle in order to prevent occurrence of hitch stitches, there is provided a needle bar that obviates a necessity for an additional rotation mechanism for rotating the sewing needle. A needle bar includes: a needle bar body having a vertically-movable sleeve and a guide bush; a sleeve provided in the needle bar body and having openings, and the like, where balls are to be placed; a cam shaft that has a disc-shaped portion which is provided in the needle bar body, an upper shaft which is provided with a pair of grooves or the like having helical grooves and which is inserted in the sleeve, and a lower shaft which is formed so as to protrude downward from a guide bush; and a joint secured to the lower shaft for securing a sewing needle.

Abstract: In relation to a sewing machine having a function of rotating a sewing needle in order to prevent occurrence of hitch stitches, there is provided a needle bar that obviates a necessity for an additional rotation mechanism for rotating the sewing needle. A needle bar includes: a needle bar body having a vertically-movable sleeve and a guide bush; a sleeve provided in the needle bar body and having openings, and the like, where balls are to be placed; a cam shaft that has a disc-shaped portion which is provided in the needle bar body, an upper shaft which is provided with a pair of grooves or the like having helical grooves and which is inserted in the sleeve, and a lower shaft which is formed so as to protrude downward from a guide bush; and a joint secured to the lower shaft for securing a sewing needle.

Abstract: 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.

Abstract: 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 section 40 and a downstream grip section 60 for gripping a needle thread and a turning section 80 for turning the needle thread. In a torque control zone, rotating force is imparted to a turning arm in accordance with a torque value.

Abstract: 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.

Abstract: 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.

Abstract: 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 section 40 and a downstream grip section 60 for gripping a needle thread and a turning section 80 for turning the needle thread. In a torque control zone, rotating force is imparted to a turning arm in accordance with a torque value.

Abstract: 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 110, a middle shuttle presser 130, a middle shuttle 150, a bobbin thread tension control mechanism 200, a shuttle actuation unit 250, and a bobbin 300. The middle shuttle 150 has a magnet 190. A magnet 270 is disposed, in close proximity to the magnet 190, on an arm 260 attached to a rotary shaft of a shuttle actuation motor 252 provided in the shuttle actuation unit 250. The middle shuttle 150 is rotated by rotating the magnet 270 by means of the motor 252. Further, a rotary disc 210 is provided, in close proximity to the middle shuttle 150, on a rotary shaft of a bobbin thread tension control motor 202 of the bobbin thread tension control mechanism 200 and is provided with a magnet 214. A magnet is disposed on a part of the bobbin 300 facing the rotary disc 210.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.

Abstract: An apparatus for synchronously controlling the actual operation of a machine using one or more motors, such as servo motors, by simulating in program form a combination of selectable machine mechanisms, including drivers, connecting shafts, clutches, gears and cams. Each such machine mechanism is represented by a virtual mechanism, preferably as a software module that contains information uniquely identifying the module, operation information that defines the generation of position information and connection information that defines other modules to which connection is made. The software modules comprise drive modules for generating position information, transmission modules for simulating the transmission mechanisms and output modules for outputting motor commands.