A sewing machine for sewing a stitch into an article is provided. The sewing machine includes a support structure, a first head and a second head. The first head is coupled to the support structure and includes a coupler contained within a second actuator assembly and 360° rotatable relative to the support structure and a first stitching element rotatable with the coupler and translatable via a first actuator assembly relative to the coupler. The second head is coupled to the support structure and includes a coupler contained within the second actuator assembly and 360° degree rotatable relative to the support structure and a second stitching element rotatable with the coupler via the first actuator assembly.

A motor drive system includes a rectifier circuit, a controller, a modulator circuit and a direct current (DC) motor. The rectifier circuit is configured to convert an alternating current (AC) voltage to a DC voltage. The controller is configured to output a control signal. The modulator circuit includes a pulse generation module, a feedback determination module, a pulse modulation module and a driving module, and is configured to generate a modulated DC driving signal based on the DC voltage and the control signal generated by the rectifier circuit and the controller. The DC motor is configured to operate in accordance with the modulated DC driving signal generated by the modulator circuit.

A motor drive system includes a rectifier circuit, a controller, a modulator circuit and a direct current (DC) motor. The rectifier circuit is configured to convert an alternating current (AC) voltage to a DC voltage. The controller is configured to output a control signal. The modulator circuit includes a pulse generation module, a feedback determination module, a pulse modulation module and a driving module, and is configured to generate a modulated DC driving signal based on the DC voltage and the control signal generated by the rectifier circuit and the controller. The DC motor is configured to operate in accordance with the modulated DC driving signal generated by the modulator circuit.

A driving clutch device for a sewing machine includes a drive shaft, a passive member, a clutch seat, an actuating seat, a power unit, and a clutch member. Through fixing the passive member and the clutch seat onto the drive shaft, rotatably disposing the actuating seat, the drive shaft, and returnably disposing the clutch member to the clutch seat, the clutch seat and the actuating seat are able to move synchronously when the clutch member is in the engaged position, but not to move synchronously when the clutch member in the disengaged position, thereby achieving the driving and clutch controls only by the clutch member, the passive member, the clutch seat and the actuating seat. Therefore, the driving clutch device is simpler and the driving is more direct and instant, thereby reducing assembly costs and the error of action coordination.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A sewing machine includes a needle plate, a feed dog configured to move a workpiece, a vertical drive mechanism configured to vertically drive the feed dog, a switch mechanism, a cutting mechanism, and an actuator. The switch mechanism is configured to switch from an active state where the feed dog is driven, by the vertical drive mechanism, above and below an upper surface of the needle plate to an inactive state where an upper surface of the feed dog is maintained below the upper surface of the needle plate. The cutting mechanism includes a blade configured to cut a thread at a position below the needle plate. The actuator is configured to commonly drive the switch mechanism and the cutting mechanism.

A sewing machine includes a needle plate, a feed dog configured to move a workpiece, a vertical drive mechanism configured to vertically drive the feed dog, a switch mechanism, a cutting mechanism, and an actuator. The switch mechanism is configured to switch from an active state where the feed dog is driven, by the vertical drive mechanism, above and below an upper surface of the needle plate to an inactive state where an upper surface of the feed dog is maintained below the upper surface of the needle plate. The cutting mechanism includes a blade configured to cut a thread at a position below the needle plate. The actuator is configured to commonly drive the switch mechanism and the cutting mechanism.

A sewing machine according to the present invention includes: an upper shaft that drives a needle and a balance; a lower shaft that drives a hook and a feed dog; an upper and lower shaft belt that synchronizes rotation of the upper shaft with rotation of the lower shaft; and an idler unit that pushes an idler into the upper and lower shaft belt to change a tension side belt length, in which the idler unit includes a transmission mechanism connected to the upper shaft or the lower shaft, and a rotating body mechanism provided with the idler and having a rotating body that rotates in synchronization with the upper shaft or the lower shaft by the transmission mechanism, and a pushing amount of the idler into the upper and lower shaft belt is changed according to rotation of the rotating body.

A sewing machine system includes an optical encoder which senses relative movement between the sewing machine and fabric and varies the stitching speed of the sewing machine to create stitches according to a user selected stitch length.

A sewing machine system includes an optical encoder which senses relative movement between the sewing machine and fabric and varies the stitching speed of the sewing machine to create stitches according to a user selected stitch length.