Abstract: This invention relates to sewing machine drive devices, and more particularly to a sewing machine drive device which, in order to stop the sewing needle at a desired position, drives the sewing machine at an ultra low speed and changes the speed of the sewing machine to a desired value immediately before the needle is stopped. The device comprising a sewing machine drive mechanism having an induction motor (14) and a braking unit (18), and a position detector (24) coupled to the output side of the induction motor, for detecting a sewing needle's position, the induction motor being subjected to variable speed driving by a motor speed control circuit (32) including an inverter circuit, and the braking unit (18) being operated with the aid of a detection signal from the position detector (24).

Abstract: The invention makes it possible to rotate an arm shaft of a sewing machine without a mechanical clutch between the hand wheel and the arm shaft. The position of the hand wheel which previously was very dependent on the mechanical system, can now be chosen so that the best possible ergonometry is obtained. Output of an electronic sensor of the rotation of the hand wheel and another sensor of the movement of the arm shaft are compared in an electronic unit, and as long as there is a difference in the outputs of the sensors the electronic unit will cause driving of the sewing machine motor so that the difference will be zero. The movement of the hand wheel is thus repeated on the arm shaft.

Abstract: A pulse generator for a sewing machine drive, having a shaft revolving synchronously with the main shaft of the sewing machine. The pulse generator shaft is connected with two support elements which carry a strobe disk provided with control segments of bright and dark zones, the strobe disk extends between pairs of light emitting and light receiving components. The strobe disk includes a first partial disk non-rotationally connected with one support element and a second partial disk arranged adjacent and non-rotationally connected with the other support element, the angle regions of the mutually correlated bright and dark zones of the control segments of the two partial disks differing from each other, one support element being rotatable relative to the other support element, so as to change the bright and dark zones of the strobe disk.

Abstract: A method of sewing the corners of a double seam, employing a two-needle machine the two needle rods of which each may be mutually independently engaged and disengaged. The method uses control means to arrive at the corner point of the inner seam, disengaging the internal needle rod, furthersewing to the corner point of the outer seam, stopping the sewing machine with the outer needle penetrating the workpiece, then rotating the workpiece, sewing the thus rotated outer seam, and engaging the inner needle rod.

Abstract: A sewing machine automatically sews a seam which ends at a desired point. The last n stitches, preferably the last two stitches, are of substantially equal length. A counter counts pulses while the work is being fed to the needle. The machine detects when the trailing edge of the work passes by a predetermined location ahead of the needle. Upon such detection, the contents of the counter are used to calculate the proper stitch pitch for the last two stitches. The stitch pitch is varied as necessary during sewing of the last two stitches in the seam.

Abstract: A motor controller for a sewing machine starts to count the number of pulse signals issued during rotation of a motor after reception of a stop signal and the detection of the needle position, and thereby sets a speed value for controlling the rotation speed of the motor so that it gradually slows based on the result of the counting of the pulse signals and so that the rotation speed of the motor goes to zero when it reaches a predetermined low value.

Abstract: An electronic control device for the needle driving motor in a sewing machine, comprising an electronic circuit which employs logic gates to obtain a simple, reliable and cheap control device.

Abstract: The invention relates to a sewing machine provided with a needle reciprocated according to rotations of a main shaft and work feeding devices actuated synchronously with rotations of the main shaft, setting a margin to sew from a trailing edge to a sewing end position. The sewing machine includes devices for computing a terminal stitch length according to a set margin width. Control devices are provided for controlling a sewing to be carried out for coping with that which corresponds to the terminal stitch length computed by the computing device. The sewing machine further comprises computing devices for applying a correction to at least one of a number of stitches and a feed pitch, as occasion demands, where there arises the remainder as the result of an operation of the computing devices, and control devices for controlling the sewing to be carried out according to the computed result.

Abstract: An automatic stitch pitch adjusting apparatus for a sewing machine allows the last stitch point to be terminated at a pre-set point. Three workpiece-end sensors are positioned respective a needle hole position to precisely calculate the required actual stitch line length. Reference signals generated by rotation of a main shaft are used to calculate both the required number of stitchings and the adjusted stitch pitch to terminate stitching at the pre-set point. Where the workpiece end line is not normal against the feeding line, the pre-set margin distance is adjusted to calculate the actual required stitching line length to the last pre-set point.

Abstract: A sewing machine, and a control device for the needle driving motor comprising an electronic circuit which employs logic gates and at least one capacitor for its working in such a way as to obtain a simple, reliable and cheap control device.

Abstract: A sewing machine driving system comprises: a reluctance motor operatively coupled to a sewing machine main shaft and having a stator and a rotor; a drive circuit for driving the reluctance motor; an angular position detector for detecting the angular position of the rotor with respect to the stator; a needle position detector for detecting the position of a sewing needle connected to the main shaft; a first control unit responsive to a drive command and a signal from the angular position detector for driving the reluctance motor at variable speeds; and a second control unit responsive to a stop command and signals from the angular position detector and the needle position detector for braking the reluctance motor to stop the sewing needle in a prescribed needle position.

Abstract: In a sewing machine which is so designed that its cloth presser driven to press a material to be sewn for a sewing operation is automatically released when the sewing operation is ended, a sewing machine control device comprising drivers for operating a brake to stop the vertical movement of the needle, for operating the cloth presser, and for operating a thread wiper and a control section. When the needle is moved to its upper position at the final stage of the sewing operation, the control section operates the driver for the thread wiper and restores, after the thread wiper has been restored, the cloth presser. Alternatively, if the thread wiper isn't used, when the needle is moved to the upper position, the control section operates the brake and releases the cloth presser whereby the time which elapses until the cloth presser has been released is shortened.

Abstract: Herein disclosed is a control unit for providing seam length control of a sewing machine which comprises: a main shaft; a sewing needle in accordance with the rotations of the main shaft for forming stitches in a work fabric which is placed on a work supporting surface so that it may be sewn; a feed dog for feeding the work fabric while passing a sewing point of the sewing needle; a work feed mechanism including a feed bar for carrying the feed dog and a feed shaft for supporting the feed carriage, the work feed mechanism being adapted to impart motions in a feeding direction to the feed dog by the reciprocating rotations of the feed shaft in accordance with the rotations of the main shaft; and mechanical adjusting means interposed between the work feed mechanism and the main shaft for adjusting a feed pitch of the feed dog by changing the reciprocating stroke of the feed shaft.

Abstract: A sewing machine has an automatic control system. This system provides for an automatic sewing mode for sewing according to previously stored sewing data and an ordinary sewing mode for sewing independently of the stored sewing data. When an interruption signal is generated by an interruption signal generating device during sewing process in the automatic sewing mode, the ordinary sewing mode is set and the pressure on the presser foot is released. Therefore, it is capable of smoothly feeding a material when feeding direction of the material is varied.

Abstract: In a control device for a sewing machine control apparatus wherein an electric motor generates a reverse torque against a torque due to a load on the sewing machine in abeyance state, to hold a sewing needle in an upper or a lower position, the reverse torque reaches a maximum value by a known feedback system at its turn to a predetermined revolution angle. The control apparatus is devised such that, when it is further turned in excess of the predetermined revolution angle, the reverse torque falls to zero, hence the driving motor remains at the position turned to the predetermined revolution angle.

Abstract: The present invention provides a machine driving apparatus which is composed of a brushless motor for switching the energization phase of the stator winding in accordance with the position of a rotor with a permanent magnet being provided in a rotor as a machine driving motor, compares a speed instructing signal to be generated from a speed instructing unit 32 in accordance with the displacement amount of a machine pedal 31 with a speed detecting signal detected by a speed detector 44 to control the rotational speed of a motor 42, also damps in reverse operation the motor 42 with a stop instructing signal to be generated by a position instructing unit 33 in accordance with the operation of the machine pedal 31 and a needle position detecting signal detected by a needle position detector 46 to stop the machine needle in a given position.

Abstract: A stepping motor is initially set while it passes through a full moving range at comparatively low pulse frequency, and it is discriminated whether the motor moves accurately in response to driving pulses between detecting points until the motor passes one detecting point and again reaches this detecting point.

Abstract: A presser device for a sewing machine, comprising: pressing means reciprocally movable between a holding position in which it presses and holds a workpiece and a releasing position in which it is spaced the farthest from the workpiece; drive means for driving the pressing means; means for controlling the drive means so that the pressing means is brought into the holding means before the start of the sewing operation of the sewing machine; means for controlling the drive means so that the pressing means is brought from the holding position to the releasing position after the end of the sewing operation; timer means for setting a predetermined time from the instant when the pressing means is brought into the releasing position; and means for controlling the drive means so that the pressing means is brought from said releasing position to an optional intermediate position between the releasing position and the holding position after lapse of the predetermined time.

Abstract: A sewing machine has a rotatable machine head and a bobbin drive unit which is rotated in synchronism with the machine head. The machine head and a needle reciprocally movably mounted on the machine head are independently driven through coaxially disposed inner and outer shafts. The reciprocal movement of the needle is detected by a detector mounted on the machine head. When only the machine head is required to be rotated, the shaft for driving the needle is also rotated so that the needle is held in its top dead point.

Abstract: The invention relates to an electronic system for the continuous speed control, with stopping at fixed preselected points for industrial sewing and/or overcasting machines. The invention also relates to a system which can afford additional control of the electromagnetic operational components e.g. the presser foot, of cutting device and of thread loosening device, using a driving system with an asynchronous motor and an electromagnetic coupling.

Abstract: This invention relates to sewing machine drive devices, and more particularly to a sewing machine drive device which, in order to stop the sewing needle at a desired position, drives the sewing machine at an ultra low speed and changes the speed of the sewing machine to a desired value immediately before the needle is stopped. The device comprising a sewing machine drive mechanism having an induction motor (14) and a braking unit (18), and a position detector (24) coupled to the output side of the induction motor, for detecting a sewing needle's position, the induction motor being subjected to variable speed driving by a motor speed control circuit (32) including an inverter circuit, and the braking unit (18) being operated with the aid of a detection signal from the position detector (24).

Abstract: A position detecting device of a contacting system is incorporated in a computerized sewing machine, which actuates in relation with an output shaft of a pulse motor at an initial setting during sewing operation of a feed control pulse motor or an amplitude control pulse motor, outside of the control region of each of said pulse motors, and the pulse motors are initially set within said control regions by signals from the position detecting device. Therefore a device for initially setting the computerized sewing machine may be provided which is excellent in durability and could promise a stable initial setting for a long period of time.

Abstract: A drive and control device for sewing machines, automatic sewing installations, and the like, with a recognition unit which responds for the purpose of end recognition when the sewing tools have approached a predetermined spacing from the desired seam end. The drive and control device also includes a preselection stitch counting unit, which can be triggered by means of the recognition unit, for the presetting of a predetermined number of remaining stitches still to be executed subsequently to the end recognition, and a correction unit for the performance of a stitch correction in dependence on the respective needle position at the instant of end recognition. The correction unit serves for automatically varying the length of at least one of the remaining stitches.

Abstract: When a sewing machine is stopped, it is electrically indicated whether a needle is positioned at a range where the thread passing is available so that intermittent indication during stitching operation is not made. The sewing machine is provided with a device including a neon lamp and a light interrupting member. The sewing machine has on its exposed front surface lighting indicators which are illuminated by the light of the neon lamp if this light is transmitted by the interrupting member which is mounted on or in the vicinity of the movable device for vertical movement of the needle so that the indicators indicate in the inoperative position of the sewing machine that the thread may be passed in a thread passing device.

Abstract: Sewing operations are automated, at least partially, using a controllable sewing machine. In an intial recording phase for the sewing operation to be effected, there are put into memory the instantaneous values of three sensed parameters, i.e. the elapsed time of sewing, the position of a sewing speed control element and the length of the sewing, at each time the position of the speed control element changes under the action of the operator. Then, in a reproduction phase, the time is detected in continuous fashion, as is the distance sewn, and the position of the speed control element is changed at each moment for which the time detected is equal to a time recorded, or for which the length sewn is equal to the length recorded.

Abstract: A sewing machine for automatically making edge-parallel seams comprises a scanning device for recognizing the geometric form of the workpiece edge and a pressure piston lowerable laterally of the stitch formation point. For straight workpiece edges extending at an angle to each other, the pressure piston, having been lowered onto the workpiece with the sewing machine stopped, is rotated around the needle which is inserted in the workpiece, the workpiece being taken along accordingly. For a convexly arcuate edge pattern, first the lateral distance of the pressure piston from the needle is readjusted in such a way that it corresponds to the radius of the edge arc (e.g. scallop). Thereafter, with the sewing machine continuing to run, the pressure piston is lowered, whereupon the feed dog of the sewing machine rotates the workpiece around the pressure piston.

Abstract: A method for approaching a predeterminable end point of a seam spaced from the edge of a workpiece, with a sewing machine which comprises an adjustable needle and lower transport, a sensor arranged before the needle and triggering the process for the positioning of the needle in the end point during passage through the edge, a pulse generator coupled with the main shaft of the sewing machine for the delivery of counting pulses for a pulse counter, and a micro-computer which controls the action of the feed means as a function of the pulses originating from the sensor and from the pulse generator. To execute a desired shortening of the length of one or more of the last stitches before the end point of a seam, the workpiece is moved back by the difference between the desired stitch length and the stitch length set by the setting device, before execution of the adjusted feed.

Abstract: A foot control of the sewing machine can be actuated from a neutral position in two directions. In one case, a variable resistance becomes effective which produces regulating voltages within a determined range. A logic circuit with comparators produces for this voltage range a condition in which the driving motor of the sewing machine is controlled to operate with a number of turns corresponding to the voltage range. When the machine is stopped the needle is automatically positioned in its upper stop position. By repetitive actuation backward of the foot pedal the needle may be positioned in its bottom stop position and again in its upper stop position and so on. The logic treatment of the control signals from the foot control permits to transmit these signals for all required instructions through a two wire cable which is already required for the speed control.

Abstract: A plurality of photoelectric detector plates are mounted in successive layers on a coupling secured to a sewing machine arm shaft, and have light shields disposed concentrically so as not to be overlapped. Light-emitting means is arranged on one side of the photoelectric detector plates for emitting light toward the latter, and photodetector means is positioned on the other side of the photoelectric detector plates for receiving the light from the light-emitting means. Conditions of the sewing machine can be detected by the manner in which the photodetector means receives the light. The photoelectric detector plates are pressed axially of the coupling and adjustable into given angular positons, respectively, with respect to the coupling.

Abstract: In a sewing machine, particularly an industrial sewing machine, with a needle which can be driven up and down by means of a needle bar, a feed dog for the forward transfer of the workpiece in co-ordination with the needle movement, an actual feed rate sensing device which supplies a corresponding electric signal and at least one sensor for detecting a workpiece edge, for the purpose of increasing the accuracy of the positioning of the corner stitch of a seam portion with acceptable constructional expenditure, a device is provided for displacing the longitudinal axis of the needle parallel to the sewing direction as a function of the actual feed rate sensing device on the one hand and the detection of a workpiece edge by the sensor on the other.

Abstract: An automatic sewing machine including a sewing machine mechanism head for foaming a seam (switch pattern) on a web, a web presser for pressing the web, a driving mechanism for moving the web presser along X and Y axes in accordance with a predetermined pattern, and a control device for controlling each of the above, wherein the control device determines the start position of sewing at a fixed initial position or another designated position within a sewing area in accordance with the setting of a switch. The start position of the seam pattern may be selected in accordance with the formation of the seam pattern and properties of the web to achieve a highly efficient sewing operation.

Abstract: An adaptive semi-automatic sewing system (10) comprises a sewing machine (12), a drive unit (42) including a variable speed motor and encoder for counting stitches sewn and for sensing the rotation of the motor, at least one material edge sensor (40a) mounted ahead of the needle (22) of the sewing machine, and a microprocessor controller (51) coupled to the sewing machine controls. Accurate control of seam lengths and end points is achieved by initiating countdown of a variable number of final stitches responsive to detection of the material edge by the sensors (40a). The system includes controls (98) coupled to microprocessor controller (51) for dynamically adjusting the sensitivity of the sensors (40a) for variances in the materials being sewn.

Abstract: A driving control device for an electronic sewing machine has a computer and an automatic needle stop system. The needle stopping arrangement is responsive to operation of the foot control regulator, and is arranged to stop the needle in its upper position in response to a first raising of the regulator, and is responsive to a second raising of the regulator within a half cycle of the machine operation for stopping the needle at its lowermost position.

Abstract: A device for stopping the machine drive of a needle movable in cooperation with a rotary hook of a sewing, embroidering or tufting machine upon a thread breakage comprises a thread cutting mechanism which includes a thread catcher movable through the needle path and a switching mechanism which is connected to the drive for disconnecting it and which becomes effective upon a thread breakage. The device includes a movably mounted thread feeler carrier having a thread feeler which is adapted to be located between the needle and the rotary hook. The drive mechanism for actuating the thread catcher includes control cams which are engageable with lifting cams so as to project the feeler out of the path of motion of the thread between the needle and the rotary hook. The thread feeler is associated with a piezoelectric element and the deflection of the feeler by the thread produces a pulse which regulates the drive mechanism for the sewing machine and effects the stopping thereof when the threads are cut.

Abstract: A semi-automatic sewing machine control system responsive to successive signals from a sensor, such as a ply edge detector, influences in predetermined sequence a series of selected machine operations. This system accommodates interchangeably any variety of work sizes provided that the same sequence of sewing machine operations is involved.

Abstract: An adaptive semi-automatic sewing system (10) comprises a sewing machine (12), a drive unit (42) including a variable speed motor and encoder for counting stitches sewn and for sensing the rotation of the motor, at least one material edge sensor (40) mounted ahead of the needle (22) of the sewing machine, and a microprocessor controller (51) coupled to the sewing machine controls. Accurate control of seam lengths and end points is achieved by initiating countdown of a variable number of final stitches responsive to detection of the material edge of the sensors (40). The speed of the sewing machine at the time the material edge is detected is monitored and compared to a reference speed. The number of final stitches is then dynamically adjusted to compensate for the speed variance from the reference speed.

Abstract: A control system for stopping the operation of a sewing machine at a prescribed stop position includes a detector for generating signals indicative of detected positions of a needle of the sewing machine and a signal indicative of a detected speed of operation of the sewing machine. A control device stops the operation of the sewing machine in response to one of the signals indicative of the needle positions when the speed of operation of the sewing machine reaches a predetermined stop-ready speed. The control device has a selector for selecting either one of the options of detecting the stop-ready speed reached by the speed of operation of the sewing machine with a program stored in the control device and with one of the signals from the detector. The detector can thus detect stop-ready speeds for different sewing machine types without changing the program stored in the control device.

Abstract: A sewing machine is provided with an upper thread dyeing mechanism for dyeing an upper thread a given color while driving the sewing machine. An upper thread feeding mechanism is also provided for the sewing machine and operative in combination with the dyeing mechanism when a stitching operation is initiated or a change in color of the upper thread is required. A predetermined amount of the upper thread, which remains to be located on the sewing machine, is drawn out by the feeding mechanism, while being colored by the dyeing mechanism.

Abstract: A workpiece holding-down device for a sewing machine comprises a spring-loaded presser bar and foot assembly supported in the framework of said sewing machine, a drive mechanism for moving said assembly vertically, and a control circuit for controlling the movement of said presser bar. The foot assembly includes signal means for positioning the presser bar and foot assembly in a controlled position in response to the actuation of an operation member or stored information.

Abstract: A speed control apparatus for a sewing machine in which two separate circuits are provided for controlling driving, braking and stopping of the sewing machine. An output of one of the speed setting circuits is selected and applied for driving, braking and stopping the sewing machine. Operating levels for the two speed setting circuits are independently adjustable.

Abstract: A sewing machine with at least one feed means, the feed amount of which is variable by means of a positioning device acting on at least one positioning gearing; with a system for approaching a predeterminable end point of a seam in spaced relation to the edge of a workpiece; with a sensor disposed before the needle which during passage of the edge triggers the process for the positioning of the needle in the end point; with a pulse generator coupled with the main shaft of the sewing machine for the delivery of counting pulses for a pulse counter and a microcomputer which interrupts the action of the feed means as a function of the pulses emanating from the sensor and from the pulse generator in the end point.

Abstract: A semi-automatic split needle bar sewing machine (10) includes a sewing machine (12) which is driven by a motor (26) that drives a left needle (22) and a right needle (23). A presser foot (24) is operated by presser lift actuator (30). The needles (22) and (23) can activate in unison or independently by use of fall out actuators (41) and (43), respectively. A control chassis (50) includes a microprocessor controller (51) that is programmable through an input panel (44). An edge detector (40) detects the edge of the material to provide feedback for the microprocessor controller (51). The microprocessor controller (51) is operable to sew a decorative pattern with mitered corners by sensing the pivot point of the mitered corner and automatically disengaging one of the needles (22) or (23).

Abstract: A sewing machine comprises a pedal position detector for detecting the position of the manually operated foot pedal of the machine and generating therefrom a pedal position indicating digital signal comprising a set of a predetermined number of binary digits. The sets of binary digits are organized into a plurality of command signals each comprising a plurality of sets of binary digits corresponding to adjacent positions of the pedal for indicating a specified operating condition of the sewing machine. The sewing machine is operated in response to the command signal.

Abstract: The circuit arrangement comprises a speed control system responsive to a speed signal indicative of the rotational speed of an arm shaft driving the sewing needle in the same manner as in known arrangements. Although the circuit arrangement operates in the same manner as in the known arrangement when a foot pedal is other than a neutral position, once the foot pedal is released to be in the neutral position, particularly provided speed setting data is used where the speed setting data value decreases as the rotational angle of the arm shaft increases. With this arrangement the sewing machine is capable of operating at a speed higher than conventional one during needle positioning with the speed being sufficiently reduced just before the needle is stopped. Thus a time length required for the last stitch has been remarkably reduced, providing efficient sewing work without deteriorating positioning accuracy.

Abstract: A method and apparatus for automatically positioning a reciprocating needle while rotating the motor a minimum number of degrees. Apparatus is provided for sensing the motor angle and comparing it with a preset braking angle. After the braking angle has been reached, the motor is decelerated until it reaches a needle positioning speed, whereupon the motor angle is again sensed and compared to the needle positioning angle. The motor rotates until the needle positioning angle has been reached, whereupon the brake is reapplied to stop the motor at the desired needle position in a minimum time duration without performing an additional stitch.

Abstract: A sewing machine for sewing shaped seams comprises equipment for exactly positioning an end stitch. By means of two edge sensing sensors provided one after the other in the feed direction, a pulse generator coupled to the main shaft, and a microprocessor, the difference between the desired feed length of the workpiece and the actual feed length thereof is determined. A microprocessor controls a step motor for adjusting a stitch setting device, the adjustment being a function of the difference between the desired and actual feed lengths of the workpiece and of the angular position of the main shaft at the instant of response of the second sensor. In this way, the length in excess of the last stitch which, without a correction, would extend beyond the predetermined end point, is uniformly distributed among the last stitches of the seam, while at the same time taking into account slippage between the feed dog and the workpiece.

Abstract: A sewing machine is with a device for producing corner seams comprising a sensor which is located ahead of the needle and which releases the operation of stopping the needle at a predetermined corner point as soon as an edge of the work passes by. To exactly control the sticking in of the needle at a predetermined corner location, a pulse generator for delivering counting pulses and coupled to the main shaft of the sewing machine, is connected through a switching element to a setting counter, and is effective only during the advance phases of the feed dog motion. In addition, the sensor is connected to the switching element to switch it on as soon as the oblique edge of the work passes by, and the setting counter is connected to a device for instantly stopping the advancing effect of the feed dog, and to a device for stopping the sewing machine in the lowermost position of the needle, to release the operation of these devices as soon as a presettable number of pulses is reached.

Abstract: A microcomputer-based motor control system provides overload protection by incrementing a register whenever a full power condition exists and decrementing the register when less than a full power condition exists. When the register reaches a predetermined value, this indicates an overload condition.

Abstract: An electronically controlled household sewing machine includes an arrangement for needle positioning. The machine responds to a tap of the foot controller for stopping the sewing machine at the next change of state of the armshaft timing signal.

Abstract: A pattern sewing machine comprises a cloth feeding mechanism for moving a piece of cloth; a sewing machine mechanism driven independently of the cloth feeding mechanism; a memory element in which control data including pattern data and sewing machine drive data are stored; a control circuit for synchronously driving the cloth feeding mechanism and the sewing machine mechanism according to the control data stored in the memory element; a temporary stop instruction for stopping the sewing machine mechanism during sewing; and a minute movement instruction for driving the cloth feeding mechanism only, the control circuit having a function of driving the cloth feeding mechanism according to the minute movement instruction after the cloth feeding mechanism has been stopped by the temporary stop instruction, and a function of driving the cloth feeding mechanism according to the pattern data thereafter.