Pfaff Industriemaschinen Gmbh

G.m. Pfaff Aktiengesellschaft

G.m. Pfaff Aktiengesellschaft in Insolvenz

Edgar Butzen

Karl-Ludwig Manuel

Gunther Denuell

Walter Hager

Kurt Arnold

Karl-Heinz Walther

Fritz Jehle

Manfred Neurohr

Karl Manuel

Lothar Bruehl

Lother Br&uuml;hl

A sewing machine has a device for steering towards a predetermined end (E) of a seam (B ). 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.

Sewing machine comprising a device for steering towards the end of a seam

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. A bobbin can be inserted into the bobbin housing with at least two chambers separated from one another by a radially directed web. One chamber (the residual thread chamber) accommodates a residual thread length and the other chamber (the main chamber) accommodates the main thread length. The front surface of the web faces the infrared laser light transmitter as well as the outer surface of the flange of the bobbin. This outer surface is adjacent to the front surface, reflecting light, wherein the flange has openings for the detection beam.

Device for monitoring the bobbin thread on double thread lockstitch sewing machines

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.

Sewing machine with speed-dependent stitch correction

Shortening of needle thread end at the beginning and end of sewing in

Sewing machine with thread monitor

Growing community of inventors

Landstuhl, Germany

Edgar Butzen