Pfaff Haushaltmaschinen Gmbh

Dorina Nahmaschinen Gmbh

Pfaff Ag Haushaltsmaschinen

Pfaff Hauschaltmaschinen Gmbh

Jurgen Hartwig

Willi Meier

Gunter Meier

Patrice J Kemmel

Sewing machine with electronic control device

A device for regulating the RPM of an electromotor with an RPM generator coupled to it for generating pulses, measures the intervals between the pulses of a measure of the RPM of the motor. The device includes an oscillator for generating clock signals, which are transmittable to a counter, which counts the number of clock signals between successive pulses of the oscillator, a register, which accepts the counter indication and a device for generating a control value for correcting the RPM of the electromotor over a digital-to-analog converter connected in series to the motor. To generate the control value for regulating the RPM, and RC network containing a manually adjustable control resistance is provided, the capacitor of which can be short-circuited by a switch, which can be activated by an oscillator-driven contact mechanism. The capacitor is additionally connected to a circuit element for switching on the counter, whose switching off can be activated by the oscillator-driven contact mechanism.

RPM regulation of an electromotor

A sewing machine has an electronic control for the production of at least one stitch pattern consisting of a plurality of different single stitches, with a read-and-write memory RAM for storing in memory at least the single stitches of the stitch pattern and with a feed mechanism whose feed adjustment occurs by a step motor controlled in accordance with the stored data of the read-and-write memory within the inactive phase of the feed mechanism. To carry out a feed variation exceeding the maximum number of steps of the step motor between two predetermined sewing stitches, the control unit contains a comparator which compares the magnitude of the displacement amount of the step motor before the next displacing movement is carried out with a given maximum displacement amount, in order to prevent a stitch formation between the point of insertion of the previous stitch and the desired point of insertion of the next following stitch when the maximum displacement amount is exceded.

Sewing machine for producing a stitch pattern

In an electrically controlled sewing machine equipped with means for varying the feed and the needle position for individual stitches and with a program storage for storing consecutive sewing programs, the display is made easily understandable and the display unit remains a compact structure by providing alphanumeric display elements in a sequence and means for switching the display unit into a first state, in which a basic setting of the pattern is indicated in symbols, and into a second state in which the patterns can be indicated in the sequential order of their storage.

Sewing machine having an electronic control

A device for controlling the drive of a stepping motor to adjust the lateral stitch bight and/or the feed length of a sewing machine comprising apparatus connected to the stepping motor for rendering the stepping frequency of the stepping motor variable as a function of the speed of the sewing machine. The apparatus comprises a microcomputer which is connected to a pulse transmitter for transmitting pulses proportional to the speed of the sewing machine.

Device for controlling the drive of a stepping motor, to adjust the

In a sewing machine with a universal motor, a speed control for the motor, a lamp, and a plug connection on the sewing machine housing for connecting the power supply and speed control lines to the motor and to the lamp, for equivalent replacement of the normal impedance starter by one with integrated phase angle control, a phase angle control is provided as a speed controller which comprises a rectifier bridge consisting of diodes for current supply to the phase angle control and to the lamp, as well as a rectifier bridge with semiconductor devices controlled by the phase angle control, for the control of the motor. To leave the known three-terminal plug connection on the sewing machine housing for the connection both of the power supply and for the phase angle control, the power supply leads are connected at both rectifier bridges, the negative terminals of which are connected to the common terminal of the motor and lamp, which the positive terminal of the phase angle-controlled rectifier bridge is connected to the second terminal of the motor. The positive terminal of the diode rectifier bridge is connected to the second terminal of the lamp.

Growing community of inventors

Karlsruhe-Durlach, Germany

Jurgen Hartwig