Abstract: A sewing machine has a stitch control pulse motor for changing the needle position and is connected to a needle plate by means of an intermediate control device which is operated by a starting device of the machine, to change the needle dropping hole.

Abstract: A pattern elongation system in an electronic sewing machine includes a number of switches on the housing of the machine and a rotatable knob for actuating a pattern selecting circuit of the pattern elongation system. The pattern elongation system further includes a memory for storing stitch control data and a discriminating signal, a pulse generator operated in synchronism with rotation of the upper drive shaft of the machine and producing a timing pulse, an oscillator cooperating with the pulse generator to address the memory per stitch of the pattern, and a comparator which compares the elongation signal and the discriminating signals to cause the oscillator to determine the addresses for the stitches of pattern.

Abstract: A sewing machine with a feed dog vertically displaceable between an upper operative position and a lower inoperative position has a control element connected with a control shaft of a control motor and turnable by the latter within a predetermined range in two opposite directions, a cam element displaceable from an inoperative position to an operative position by the control element during turning of the latter in one of the directions, a cam follower normally engaging the cam element and displaceable from an inoperative position to a set position by the cam element during displacement of the latter from its inoperative position to its operative position and being further displaceable to an operative position by the control element during turning of the latter in the other of the directions, and a transmitting element operatively connected with the cam follower and the feed dog and operated by the cam follower during displacement of the latter from its set position to its operative position so as to displace

Abstract: A pattern selecting system is disclosed in which a single set of push buttons is utilized to select a first group of patterns each of which corresponds to a particular push button and a second group of patterns indicated by a series of two figure numbers.

Abstract: A stitch-length correcting sewing machine and a stitch-length measuring presser foot assembly used therein are disclosed. The sewing machine and presser foot assembly enables stitches of a predetermined length to be sewn, without the necessity of stitching a trial stitch on a piece of fabric and adjusting the sewing machine to compensate for variations in fabric type and thickness. The presser foot assembly utilizes a presser foot which is detachably securable to a presser bar. A movable presser frame slides on the presser foot as fabric is fed. A potentiometer is fixed to the presser foot and responds to sliding of the presser frame so as to enable distance moved by the presser frame to be ascertained by detecting the resistance of the potentiometer. The presser foot assembly can be used as a fabric sensor responsive to fabric motion in an electronic sewing machine.

Abstract: An upper shaft phase detecting system in which the rotation speed of the upper shaft is sensed and utilized to vary the time at which data starts to be released from an electronic memory of a sewing machine.

Abstract: An electronic sewing machine with an electronic memory and electronic circuit for controlling the needle amplitute and the fabric feed in order to form a plurality of stitching patterns includes a plurality of pattern-selecting buttons on the pattern panel of the machine, an inverse memorizing button for inversing a pattern selected by the pattern selecting buttons, a memorizing button which causes the electronic memory to store a plurality of patterns in cooperation with the pattern selecting buttons, a function selector for dropping feed dog means with respect to the needle plate in cooperation with the pattern selecting buttons, and a twin-needle button for reducing the needle lateral amplitude.

Abstract: A device for automatically adjusting the tension of a lower thread, which comprises a lower thread bobbin arranged on a bottom plate of a bobbin carrier turnably carrying the bobbin, a loop taker mounted on a magnetic shaft, and an energizing coil arranged around the magnetic shaft and providing together with said bottom plate and magnetic shaft a path of magnetic flux. The device is further provided with a detector detecting the consumed amount of the bobbin thread and a control circuit for energizing the coil when the lower thread is wound to the maximum capacity of the bobbin, interrupting the light of the detector. The detector operates the control circuit to decrease the amount of electric current applied to the energizing coil so as to set the lower thread tension back to its initial predetermined value.

Abstract: When a pulse motor in an electronic sewing machine is to be subjected to a heavy load, the pulse motor is operated at a slower speed in order to cause the pulse motor to operate at a rate in which it has a maximum torque output. For lesser load conditions, pulse motor speed is allowed to increase. Speed control of the pulse motor follows a generally trapezoidal curve, which curve includes a speed-up section and a slow-down section, and may include a flat section. That portion of the generally trapezoidal curve along which motor speed follows is determined by the distance which the pulse motor is required to move.

Abstract: A single motor controls needle swing and fabric feed in a sewing machine. The motor is connected to a transmission which alternately locks either the needle swing or the fabric feed while releasing either the fabric feed or the needle swing as the case may be. The motor is operated in accordance with a predetermined program by an electronic control system. Multiplexers are used in order to alternately transmit feed data and needle control data to the motor. Two embodiments are taught: one embodiment being purely digital in nature, and the other embodiment including an analog feedback loop.

Abstract: A sewing machine is disclosed in which a needle hole switching mechanism is activated in association with pattern stitch selection.

Abstract: The needle-shifting zig-zag unit and the work feeding unit are moved to different positions, when necessary, for successive stitches, to form a stitching pattern. Each unit is powered by the main rotating drive shaft of the sewing machine. However, each unit is provided with a respective stepper motor. Each stepper motor changes the setting of an adjuster in a reciprocating-motion generator driven by the main drive shaft. When one of these adjusters is in a constant setting, its respective reciprocating-motion generator continually generates reciprocating motion of constant corresponding amplitude, for an unlimited time, so long as the drive shaft rotates. The needle-penetration coordinates for the stitching pattern are established by continually changing the amplitude of the reciprocations performed by the two reciprocating-motion generators.

Abstract: An automatic embroidery machine is driven by information recorded on magnetic tape and utilizes a fixed sewing machine and a movable embroidery frame. An input apparatus registers user-selected points on a coordinate analysis panel, which points form embroidery patterns to be sewn, and causes embroidery information to be recorded upon magnetic tape for subsequent use in the automatic embroidery machine. The automatic embroidery machine and the input apparatus are so designed that after a continuous part of an embroidery pattern has been sewn, the embroidery frame will be moved to a next continuous part of a pattern and the automatic embroidering machine will stop, providing an opportunity for a user to change thread. The automatic embroidering machine cannot be restarted unless the user operates a controller, ensuring safe operation.

Abstract: The tension of the sewing machine's upper thread is varied automatically, in a variety of ways not requiring conscious participation on the part of the user of the machine. When one of a set of selectable stitch-patterns is selected by the user, an appropriate thread-tension value is automatically established, although the user retains the ability to adjust the automatically established tension value if he wishes. When the user swings the presser-foot lever of the machine up, to raise the cloth presser foot up from the cloth, e.g., for basting work, the thread tension is automatically lowered to a predetermined value suitable for basting, although still adjustable by the user if he thinks necessary. Where a stitch-pattern is implemented using an addressable ROM, tension command data for each stitch of the stitch-pattern may be stored in the ROM, for variation of thread tension from constituent stitch of the pattern to the next.

Abstract: A sewing machine can accept a plurality of presser feet for specific stitching applications. The invention adjusts lateral movement of the needle, feed dog operation, and needle hole size at the needle plate to conform with the presser foot used, and to thereby prevent needle breakage and skipped stitches.

Abstract: A first memory stores stitch control signals. A second memory stores these signals temporarily and reads them out to enable stitches to be formed. As a pattern is stitched, the first memory is readdressed and stitch control signals are successively written into and read out of the second memory. In one embodiment, the second memory is a RAM--in a second embodiment, the second memory is a shift register. Monostable multivibrators are used to operate the memories.

Abstract: A sewing machine which utilizes a pulse motor to vary feed rate in steps is equipped with a microcomputer that causes the pulse motor to operate in a repeated sequence in which two adjacent feed rates are alternated. By operating the computer in accordance with a manually-operable control, an overall feed rate can be produced which is intermediate the two adjacent feed rates.

Abstract: A pulse motor rotation phase adjusting system for a sewing machine includes a pulse motor operative for positioning a needle of the sewing machine in accordance with the predetermined stitch coordinates of a selected pattern. The pulse motor is adapted to be set to one of the stepping rotation phases in dependence upon the predetermined combinations of the magnetic forces generated by the windings of the pulse motor. A light interrupting arrangement is provided in the system which is connected to the output shaft of the pulse motor and serves for detecting the respective rotation phases of the pulse motor within a range of the maximum needle swinging amplitude and to produce a signal corresponding to predetermined combination of the magnetic forces, which signal is read out by a control circuit operatively connected to the pulse motor to rotate and reset the same to its initial position in accordance with said predetermined stitch coordinates when the electric power is applied to the sewing machine.

Abstract: A sewing machine has stitch forming instrumentalities synchronously operated with the upper drive shaft to produce a variety of stitch patterns using a plurality of manual pattern selecting switches to produce pattern selecting signals specific to the pattern selected in conjunction with a pulse generator which produces a pulse per rotation of the upper shaft which pulse triggers a free-running pulse from an oscillator which are then progressively registered by a counter that addresses a static memory to produce a signal for stopping the operation of the oscillator, and control means for selectively applying the counter contents to the stitch forming instrumentalities.

Abstract: The stitch-forming instrumentalities of a sewing machine are subject to small mechanical operational errors due to play in the motion-transmitting connections. The invention overcomes this problem by providing two springs which are respectively connected to a transmission element coupled to a driven mechanism of the machine, and to a drive. The two springs counterbalance one another with respect to the drive.