Pfaff Industriemaschinen Gmbh

Franz Schneider

Herbert Wenz

Gunter Link

A sewing machine which is used with manual feed movement of a sewing material has a holding device for the material that is effective during the first phases of stitching of a seam section, by which the first thread knot is held from becoming undone when short thread ends and a large feed movement are used. In a first embodiment, the holding device includes a holding foot, by a drive mechanism in addition to a presser foot which is periodically moved up and down by a drive mechanism, and a controllable drive for the holding foot. In a second embodiment, the holding device includes a presser foot, a compression spring and a decoupling mechanism by which the presser foot can be disconnected from its drive mechanism.

Sewing machine with workpiece holder for securing initial seam stitches

A method for approaching a predeterminable end point of a seam spaced from the edge of a workpiece, with a sewing machine which comprises an adjustable needle and lower transport, a sensor arranged before the needle and triggering the process for the positioning of the needle in the end point during passage through the edge, a pulse generator coupled with the main shaft of the sewing machine for the delivery of counting pulses for a pulse counter, and a micro-computer which controls the action of the feed means as a function of the pulses originating from the sensor and from the pulse generator. To execute a desired shortening of the length of one or more of the last stitches before the end point of a seam, the workpiece is moved back by the difference between the desired stitch length and the stitch length set by the setting device, before execution of the adjusted feed. For correction of the stitch length executed during the feed phase, the cloth feeder is connected with a switching gear controlled by the micro-computer for controlled switching on during its reversed feed phase which precedes the respective forward feed phase.

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Kaiserslautern, Germany

Franz Schneider