Abstract: A sewing machine has a device for steering towards a predetermined end (E) of a seam (B1). An alternating movement of the feed elements of the sewing machine, which occurs when the stitch adjusting device is set, is taken into consideration in the calculation of the target stitch length (Sb) of the final optionally shortened end stitch (Nre) of the seam, in such a way that the setting value that deviates from the target stitch length is produced.

Abstract: A sewing machine has a device for steering towards a predetermined end (E) of a seam (B1). An alternating movement of the feed elements of the sewing machine, which occurs when the stitch adjusting device is set, is taken into consideration in the calculation of the target stitch length (Sb) of the final optionally shortened end stitch (Nre) of the seam, in such a way that the setting value that deviates from the target stitch length is produced.

Abstract: A monitor is provided for a bobbin thread on double thread lockstitch sewing machines. This is preferably a sewing machine with a rotating hook with a bobbin housing accommodating the lower thread reserve. The monitor includes a revolution sensor which sends a pulse per revolution of the main shaft of the machine to a microcomputer. An infrared laser light transmitter sends a detection beam directed toward a bobbin. The beam is reflected by the bobbin or by the roll of a residual thread length to a receiver and is sent by the latter to the microcomputer in the form of signals for processing, evaluation and/or forwarding. The microcomputer is adapted to compare the different signal patterns with a detection threshold (DS) to generate signals for controlling the sewing machine. A controllable power source is connected to the microcomputer for the occasional, stepwise reduction of the output of the infrared laser light transmitter.

Abstract: A monitor is provided for a bobbin thread on double thread lockstitch sewing machines. This is preferably a sewing machine with a rotating hook with a bobbin housing accommodating the lower thread reserve. The monitor includes a revolution sensor which sends a pulse per revolution of the main shaft of the machine to a microcomputer. An infrared laser light transmitter sends a detection beam directed toward a bobbin. The beam is reflected by the bobbin or by the roll of a residual thread length to a receiver and is sent by the latter to the microcomputer in the form of signals for processing, evaluation and/or forwarding. The microcomputer is adapted to compare the different signal patterns with a detection threshold (DS) to generate signals for controlling the sewing machine. A controllable power source is connected to the microcomputer for the occasional, stepwise reduction of the output of the infrared laser light transmitter.

Abstract: In a sewing machine, the speed-dependent change in the stitch length is compensated by a speed-dependent correction of the setting of the stitch regulating device. A linear stitch length desired value curve Ss is obtained.

Abstract: In a sewing machine, the speed-dependent change in the stitch length is compensated by a speed-dependent correction of the setting of the stitch regulating device. A linear stitch length desired value curve Ss is obtained.

Abstract: In a process and a device for shortening the needle thread end at the beginning of sewing and at the end of sewing in two-thread lockstitch sewing machines, the catch thread device (23) of an already existing thread-cutting device (22; 60; 90) is moved into its thread-catching position during the first stitch formation cycle, and it is ensured, either by the selection of a suitable point in time for moving the catch thread device (23) or by a compressed air flow discharged from a compressed air line (81), that at least the reserve-side leg of the needle thread loop will be caught by the catch thread device (23). Part of the needle thread end is cut off during the return movement of the catch thread device (23) into its starting position. Furthermore, the needle thread is clamped either under a leaf spring (44), or is pushed by a sufficiently large feed step under the pressure foot, and is thus held in a frictionally engaged manner.

Abstract: The control circuit of a catch thread device has a counter for the main shaft of the swing machine. The counter counts the number of revolutions of the main shaft 26 during the reception of one of at least two signal intensities and is reset to its initial value when this signal intensity changes to the other signal intensity. When a predetermined maximum number of revolutions is reached, the counter emits a signal indicating a thread fault.