Abstract: According to the present invention, there is disclosed a microprocessor for a sewing machine which can be changed over from a normal service mode for controlling sewing operations to a diagnostic mode for controlling diagnostic programs. The drive of the diagnostic programs takes place by actuation of already present selector switches of the sewing machine and the display of the diagnostic results takes place through already present displays of the sewing machine. In order to facilitate the diagnostic, a mask is provided which can be placed on the control and displaying panel of the sewing machine and which contains indications relating to the drive of determined programs and the reading of the results. At least in one case, means are provided in order to enter and store correcting information according to the results of the diagnostic. This provides a simple and multilateral diagnostic capability and the possibility of intervention in the electronics of the sewing machine.

Abstract: A sewing maching having associated modules which can be inserted at will and which are interchangeable in a guide of the housing of the machine. The front side of the plate-shaped modules is visible in the inserted condition of the module and is provided with stitch symbols to which are assigned numbers. On the inside of the modules are arranged memories, preferably in connection with a microprocessor, which are in connection with the microprocessor of the sewing machine when the modules are inserted. By means of keys and a display, the number corresponding to the desired stitch sort can be selected and the control data from the memories of the module will be recalled in the microprocessor of the sewing machine and then used for controlling operation of the sewing machine.

Abstract: For the adjustment of the values for the length and width of the stitches there is provided rotative adjustment knobs, each of which permitting to set a counter through an incremental sensing device. The state of the counter serves for controlling the machine and an analog display consisting of a luminous beam. From a storage unit basic adjustment values for determined sorts of stitches may be introduced in the counter and utilized unchanged or arbitrarily modified for controlling the display. The adjusted value effective for controlling the machine and the basic adjustment value are displayed in a different manner on each display. This gives as a whole a diversified, pleasant to handle and clear adjustment and display.

Abstract: The button hole presser foot engages longitudinally slidably in a frame like slide which is taken along with the sewing material. The slide comprises a cord stretched in the longitudinal direction which encircles the lower end of a shaft of the presser foot shank. At the top end of the shaft is provided an impeller through which a light beam of a light source emerges toward a optoelectric transducer. During the sewing operation the slide moves with the sewing material and it drives the impeller which generates pulses each corresponding to a step of the motion of the sewing material, respectively of the slide. For determining the length of the cords, a determined number of steps, respectively of pulses is counted each time. This permits a reliable and precise determination of the length of the cords.

Abstract: A sewing machine having associated modules which can be inserted .[.at will.]. and which are interchangeable in a guide of the housing of the machine. The front side of the plate-shaped modules is visible in the inserted condition of the module and is provided with stitch symbols to which are assigned numbers. On the inside of the modules are arranged memories, preferably in connection with .[.a microprocessor, which are in connection with.]. the microprocessor of the sewing machine when the modules are inserted. By means of keys and a display, the number corresponding to the desired stitch sort can be selected and the control data from the memories of the module will be recalled in the microprocessor of the sewing machine and then used for operation of the sewing machine. .[.