Abstract: An amount of a lower thread to be supplied from a bobbin in each stitch forming operation is first determined on a theoretical basis in accordance with the stitch control data stored in a pattern memory. The sewing machine is provided with a bobbin rotation detector which detects every rotation of the bobbin to estimate a lower thread amount which has actually been supplied from the bobbin. A control unit compares the theoretical amount and the practical amount to lead out a correction coefficient which will be applied to the theoretical amount for the next stitch forming operation.

Abstract: A front operation panel is provided on a housing of an electrically controlled sewing machine, which provides a pattern list indicating a plurality of stitch patterns in a specific pattern group. One of the stitch patterns may be selected in direct reference to the pattern indication and the selected one is represented in a display section in the operational panel. The operational panel comprises a display board having the pattern list and the display section and a transparent cover superposed on the display board which includes a plurality of pressure-sensitive elements to be selectively depressed to designate the pattern indication in the pattern list. The display board may be switched to another information menu which is applicable to input operation of an original stitch pattern by successively inputting needle dropping points which should be enough to define a configuration of the original stitch pattern.

Abstract: A sewing machine capable of setting a feed pitch of a first stitch on zero in a work piece at the beginning of sewing operation, comprises: a needle reciprocable in a vertical direction and joggable in a lateral direction; a feed means which cooperates with a presser foot in operation in synchronism with the needle for feeding a work piece at a desired rate; a stitch-forming mechanism driven by a main drive motor of the sewing machine; a motor-operation detecting means for detecting operating conditions of the main drive motor; a needle-position detecting means for detecting a position of the needle having been disposed above a throat plate; and a presser-foot position detecting means for detecting a position of the presser foot relative to the throat plate, whereby a feed pitch of the feed means is set on zero at a time when the motor-operation detecting means detects a stopping condition of the main drive motor, so that a condition in which the feed pitch of the feed means is set on zero is held until a sub

Abstract: Stitching coordinates prior to finish-up stitching are used to produce finish-up stitching data, resulting in undistorted stitching in all cases. Also, stitching data is pre-read out at start-up for stitching patterns continuously and predetermined stitching coordinates are obtained from the stitching data for making initiating finish-up stitching data. Therefore, it is no longer necessary to store the finish-up stitching data or the initiating finish-up stitching data in advance in a programming memory (ROM) so that operating efficiency of the sewing machine is increased.

Abstract: An electronic zigzag sewing machine is provided with a presser foot including a switch lever pivotable between a first and second position. During buttonhole stitching operation the switch lever remains in the first position, but it is shifted to the second position when either one of longitudinal ends of a buttonhole is detected. A photo-sensor is mounted to the presser foot to output a detection signal when the switch lever is in the second position. A pattern number designating a specific stitch pattern of the buttonhole stitches is renewed to the next in response to the detection signal from the photo-sensor. A control system is provided to nullify operation of the photo-sensor during production of bar tacks of the buttonhole stitches so that the pattern number is not renewed in areas of the bar tacks irrespective of output of the detection signal.

Abstract: A color display apparatus adapted to be used in an electronic sewing machine. The apparatus consists of a sewing pattern selector, a color display for displaying the pattern selected by the selector, a fabric color sensing system, an upper thread color sensing system, and a display color controller. Fabric color information, upper thread color information, and pattern information are inputted to the display color controller. The controller operates the color display. An operator monitors the matching condition of the color of the fabric and upper thread in order to obtain the desirable matching of them in the pattern selected by means of the display color controller.

Abstract: A stitch condition setting device for an electronically controlled sewing machine that forms stitch patterns and has a reciprocating needle, a fabric feed and an electronic memory to store stitch control signals, the stitch condition setting device having an apparatus for separately designating a change in a needle amplitude amount and a fabric feed amount in accordance with a selected stitch pattern, an apparatus for switching the designating apparatus between designating the change in needle amplitude amount and designating the change in fabric feed amount; and an apparatus responsive to the designating apparatus and the switching apparatus for changing the needle amplitude amount and the fabric feed amount in accordance with the selected stitch pattern.

Abstract: A safety control device for a speed control circuit of a commutator motor having an ignition circuit includes a circuit for detecting an armature current and defining whether the commutator motor is energized with a supply current or with a free wheel current, a maintaining circuit for discriminating if the detected result is a continuously energized condition or an intermittent condition, and a bistable circuit. The maintaining circuit smoothes the detected voltage of the energized motor and maintains the voltage over at least one cycle of the power source and functions temporarily in an equivalent manner of continuous energization of the motor when power source is applied to the motor.