A sewing machine includes a sewing machine motor serving as a drive source for driving the vertical movement of a needle bar, a control part for controlling the sewing machine motor such that a sewing pitch coincides with a set value, and imaging part for imaging a seam formed in a workpiece at a needle drop position. The control part obtains the length of the most recent seam from an image of the most recent seam imaged by the imaging part and also compares the length of the most recent seam with the set value of the sewing pitch to thereby correct the number of rotations of the sewing machine motor.

A sewing machine includes a sewing machine motor serving as a drive source for driving the vertical movement of a needle bar, a control part for controlling the sewing machine motor such that a sewing pitch coincides with a set value, and imaging part for imaging a seam formed in a workpiece at a needle drop position. The control part obtains the length of the most recent seam from an image of the most recent seam imaged by the imaging part and also compares the length of the most recent seam with the set value of the sewing pitch to thereby correct the number of rotations of the sewing machine motor.

A sewing machine includes a driving unit, a throat plate, a pressing unit, a detecting unit and a control unit. The detecting unit includes a housing mounted to a connecting module of the pressing unit, a track ball rotatably disposed on the housing, and adapted for contact with a fabric placed on the throat plate, and a plurality of Hall-effect sensors disposed in the housing such that, when the fabric is moved on the throat plate, the track ball rotates relative to the fabric and the housing, so that a rotational speed of the track ball is detected by the Hall-effect sensors. The control unit is disposed for controlling a moving speed of a needle bar of the driving unit corresponding to the rotational speed of the track ball.

A sewing machine includes a driving unit, a throat plate, a pressing unit, a detecting unit and a control unit. The detecting unit includes a housing mounted to a connecting module of the pressing unit, a track ball rotatably disposed on the housing, and adapted for contact with a fabric placed on the throat plate, and a plurality of Hall-effect sensors disposed in the housing such that, when the fabric is moved on the throat plate, the track ball rotates relative to the fabric and the housing, so that a rotational speed of the track ball is detected by the Hall-effect sensors. The control unit is disposed for controlling a moving speed of a needle bar of the driving unit corresponding to the rotational speed of the track ball.

A foot controller includes: a pedal portion that is to be depressed by a foot thereon; a pedal stand on which one end of the pedal portion is supported so that the pedal portion freely pivots about a pivot portion; a speed control member that controls an operation speed of a sewing machine; and a depression suppression member that regulates and controls a depressing operation of the pedal portion in accordance with the depression speed of the pedal portion. In response to a depressing operation which does not involve an abrupt speed change of the pedal portion, the depression suppression member is not operated and the operation speed of the sewing machine is controlled according to an amount of depression of the pedal portion. In response to a depressing operation which involves an abrupt speed change of the pedal portion, the depression suppression member is operated.

A foot controller includes: a pedal portion that is to be depressed by a foot thereon; a pedal stand on which one end of the pedal portion is supported so that the pedal portion freely pivots about a pivot portion; a speed control member that controls an operation speed of a sewing machine; and a depression suppression member that regulates and controls a depressing operation of the pedal portion in accordance with the depression speed of the pedal portion. In response to a depressing operation which does not involve an abrupt speed change of the pedal portion, the depression suppression member is not operated and the operation speed of the sewing machine is controlled according to an amount of depression of the pedal portion. In response to a depressing operation which involves an abrupt speed change of the pedal portion, the depression suppression member is operated.

A foot-operated controller of a sewing machine including a first pedal that input a number of revolution of a sewing machine motor by stepping of a user, a second pedal pressed by the user, a main body that supports the first pedal, and a support unit that supports the second pedal, in which the support unit is selectively attachable in disposition where the second pedal is on the left side of the first pedal and disposition where the second pedal is on the right side of the first pedal. In both cases where the second pedal is on the left side of the first pedal and the right side of the first pedal, across an interval between the main body and the support unit, it is possible to detect the pressing to the second pedal with respect to the second element.

A sewing machine includes a movement amount detector which is configured to detect a movement amount of a workpiece, a motor which is a rotation driving source of an upper shaft configured to provide a vertical motion to a needle bar, and a control device which is configured to control the motor based on detection of the movement amount detector to maintain a constant stitch length. The movement amount detector is supported to be capable of being raised and lowered around a stitch position. The sewing machine includes a pressing unit configured to provide an upward elastic force such that a detection surface of the movement amount detector protrudes from an upper surface of a throat plate.

A sewing machine includes a movement amount detector which is configured to detect a movement amount of a workpiece, a motor which is a rotation driving source of an upper shaft configured to provide a vertical motion to a needle bar, and a control device which is configured to control the motor based on detection of the movement amount detector to maintain a constant stitch length. The movement amount detector is supported to be capable of being raised and lowered around a stitch position. The sewing machine includes a pressing unit configured to provide an upward elastic force such that a detection surface of the movement amount detector protrudes from an upper surface of a throat plate.

A sewing machine includes a driving unit, a throat plate, a pressing unit, a detecting unit and a control unit. The detecting unit includes a housing mounted to a connecting module of the pressing unit, a track ball rotatably disposed on the housing, and adapted for contact with a fabric placed on the throat plate, and a plurality of Hall-effect sensors disposed in the housing such that, when the fabric is moved on the throat plate, the track ball rotates relative to the fabric and the housing, so that a rotational speed of the track ball is detected by the Hall-effect sensors. The control unit is disposed for controlling a moving speed of a needle bar of the driving unit corresponding to the rotational speed of the track ball.