Abstract: 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.

Abstract: A sewing machine includes a main body and a quick release needle plate module. The main body includes a base seat having an inner frame, and an outer case that is mounted to the inner frame and that defines an accommodating compartment. The quick release needle plate module includes a catch member, and a needle plate that covers the accommodating compartment, that is detachably pivoted to a rear section of the inner frame, and that engages the catch member. The quick release needle plate module further includes a press member inserted through the outer case and the inner frame, and operable to push the catch member to disengage the catch member. The needle plate has a plate body that covers the accommodating compartment, and a resilient member mounted between the inner frame and the plate body for driving pivot action of the plate body away from the inner frame.

Abstract: 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.

Abstract: A feed dog device of a sewing machine includes a driving unit, a needle plate unit, a feed dog unit, an up-down transmitting unit, a horizontal transmitting unit and a direction adjusting unit. The direction adjusting unit includes a stepper motor with a variable rotational speed controlled in accordance with a speed of the driving shaft of the driving unit, and a linkage mechanism actuatable by the stepper motor to be moved to different positions so as to interfere with a horizontal reciprocating motion by the horizontal transmitting unit such that the horizontal reciprocating motion cooperates with the up-down reciprocating motion by the up-down transmitting unit to bring the feed dog unit into performing a variable moving course.

Abstract: A thread feeding device of a sewing machine includes a needle bar movable vertically to pull an upper thread through a fabric, and movable between left and right terminal positions. An imaginary plane to which the needle bar is normal is defined, and includes left and right boundary lines which pass through the left and right terminal positions. An inner rotary hook includes a thread tensing unit disposed on a hook surrounding wall. A lower thread passes through and abuts against the thread tensing unit to define at least one thread abutting point. A final abutting point where the lower thread passes through the thread tensing unit immediately before reaching the fabric is defined, and is projected on the imaginary plane at a point that is interposed between the boundary lines.

Abstract: A position indicating circuit includes: first and second input terminals for respectively receiving first and second voltages; an output terminal; a first resistor; and a second resistor having a first terminal coupled to the first input terminal through the first resistor, a second terminal coupled to the second input terminal, and a third terminal coupled to the output terminal. The second resistor is used to be actuated by a pedal of a foot controller of a sewing machine such that a voltage at the output terminal has a magnitude related to a position of the pedal. A detecting system that uses the position indicating circuit and that can determine whether the foot controller is coupled to a main body of the sewing machine is also provided.

Abstract: A method of generating an image that shows an embroidery area in an embroidery frame for computerized embroidery includes: acquiring a first image of a calibration board that has multiple feature points forming a contour approximating an embroidery area defined by the embroidery frame; identifying the feature points of the calibration board in the first image to acquire multiple graphical feature points; acquiring a geometric curved surface that fits the graphical feature points and that includes multiple curved surface points; acquiring a second image in which the embroidery area of the embroidery frame is shown; and performing image correction on the second image based on the geometric curved surface to generate a corrected image.

Abstract: A appliqué method includes: acquiring a first image of a first fabric piece; performing edge detection on the first image to acquire a plurality of edge points of the first fabric piece; calculating, for each of the edge points, coordinates of the edge point in a coordinate system corresponding to a computerized embroidery machine; and embroidering the first fabric piece onto a second fabric piece along an embroidering path formed by the coordinates of the edge points in the coordinate system.

Abstract: An image processing method includes: acquiring an image of a calibration board; acquiring a plurality of feature points in the image of the calibration board; evaluating a plurality of control parameters based on the feature points, the control parameters cooperatively defining a geometric curved surface that fits the feature points; and performing image correction on a to-be-corrected image based on the geometric curved surface to generate a corrected image.

Abstract: A appliqué method includes: acquiring a first image of a first fabric piece; performing edge detection on the first image to acquire a plurality of edge points of the first fabric piece; calculating, for each of the edge points, coordinates of the edge point in a coordinate system corresponding to a computerized embroidery machine; and embroidering the first fabric piece onto a second fabric piece along an embroidering path formed by the coordinates of the edge points in the coordinate system.

Abstract: A method of generating an image that shows an embroidery area in an embroidery frame for computerized embroidery includes: acquiring a first image of a calibration board that has multiple feature points forming a contour approximating an embroidery area defined by the embroidery frame; identifying the feature points of the calibration board in the first image to acquire multiple graphical feature points; acquiring a geometric curved surface that fits the graphical feature points and that includes multiple curved surface points; acquiring a second image in which the embroidery area of the embroidery frame is shown; and performing image correction on the second image based on the geometric curved surface to generate a corrected image.

Abstract: A buttonhole sewing guiding device of a sewing machine includes a buttonhole presser foot unit disposed on a presser foot holder of the sewing machine, and a sensing unit disposed on the buttonhole presser foot unit. A presser frame of the foot unit is movable relative to a sliding member between first and second sewing positions set in accordance with an operating distance that corresponds to a size of a button to allow first and second triggering members to initiate a sensing module for controlling operation of a sewing needle.

Abstract: An operating method for computerized machine embroidery includes steps of: (a) transmitting two portions of the stitch data sets respectively into a first storage section and a second storage section; (b) embroidering according to the portion of the stitch data sets in the first storage section; (c) after completion of step (b), the embroidery machine erasing data from the first storage section; (d) after completion of step (c), the transmitting a remaining portion of the stitch data sets to the first storage section; (e) after completion of step (b), embroidering according to the portion of the stitch data sets in the second storage section; and (f) repeating step (b) after completion of steps (d) and (e).

Abstract: 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.

Abstract: A vacuum cleaner includes a motor and an alternating current to direct current (AC-to-DC) converting unit including first and second power supplies, a DC stabilizer and a rechargeable battery. The first and second power supplies respectively convert mains electricity from a power socket into first and second DC electricity. The DC stabilizer stabilizes the first DC electricity to output stabilized DC electricity to the motor. The rechargeable battery is to be charged by the second DC electricity. When the vacuum cleaner is turned on and mains electricity is provided to the AC-to-DC converting unit, the vacuum cleaner operates in an external power supply mode, in which the first and second power supplies are activated to respectively drive the motor and charge the rechargeable battery.

Abstract: A buttonhole sewing guiding device of a sewing machine includes a buttonhole presser foot unit disposed on a presser foot holder of the sewing machine, and a sensing unit disposed on the buttonhole presser foot unit. A presser frame of the foot unit is movable relative to a sliding member between first and second sewing positions set in accordance with an operating distance that corresponds to a size of a button to allow first and second triggering members to initiate a sensing module for controlling operation of a sewing needle.

Abstract: A vacuum cleaner is used with a detachable built-in filter bag, and includes a shell, a mounting piece, an intake tube, a cover plate, a bag holder, a blocking member, a prop member, a biasing spring, and a vacuum air stream generating member. The cover plate is configured to be brought into mating engagement with the shell so as to enclose a chamber in the shell. When no filter bag is installed inside a chamber of the shell, the cover plate is prevented from being brought into mating engagement with the shell. Once the cover plate is brought into mating engagement with the shell, the prop member is brought into pressing engagement with the blocking member to lift the blocking member.

Abstract: A method for identifying reference points in a hand drawing track with a number (n) of dots includes marking a first one of the dots as a reference point; for each of a (kth) one of the dots, determining an included angle; marking the (kth) one of the dots as a reference point when the included angle associated therewith is larger than a predetermined angle; calculating an accumulated distance between the (kth) one of the dots and a last one of the reference point (s) thus marked when the included angle is not larger than the predetermined angle; and marking the (kth) one of the dots as a reference point when it is determined that the accumulated distance thus calculated is larger than the predetermined distance, 2?k?(n?1).

Abstract: In a method for controlling sewing operation of a sewing machine, a stitch needle completes an in-and-out movement on a fabric with a first tension applied to an upper thread when the stitch needle, with respect to a fabric-feeding mechanism, is at a first relative position corresponding to a first pattern part of a predetermined stitch pattern. Afterward, the stitch needle is moved, with respect to the fabric-feeding mechanism, to a second relative position corresponding to a second pattern part of the predetermined stitch pattern, and completes an in-and-out movement on the fabric at the second relative position with a second tension, which is greater than the first tension, applied to the upper thread.