Pfaff Industriemaschinen Gmbh

G.m. Pfaff Aktiengesellschaft

G.m. Aktiengesellschaft

Bernhard Mertel

Erich Willenbacher

Kurt Arnold

Reinhold Dobner

Karl-Heinz Walther

Horst Zinssmeister

Reiner Klein

Wolfgang Hauck

Robert Massen

Rainer Spickermann

Bernd Matschulat

Walter Sinn

Klaus Hoehne

A process and device for monitoring the bobbin thread on stitch-forming machines, on the bobbin of which a residual amount of thread is wound in a winding direction opposite the direction of winding of the principal amount of thread, is to ensure that a first control function will be generated at the beginning of consumption of the residual amount of thread, and a second control function is generated nearly without delay in the case of thread end or thread break. To achieve this, two signal patterns are received with a phase shift from a bobbin acting as a signal generator, and the first signal function is generated in the case of a deviation of the actual phase shift from the desired phase shift. If only one signal pattern is received, this first control function is also generated if its signal sequence deviates from a reference signal sequence. The second control function is generated if a stoppage of the bobbin lasts longer than a predeterminable number of stitches. Devices for carrying out this process, as well as a device for winding thread on the bobbin in different directions of rotation for the principal amount of thread and the residual amount of thread are provided.

Process and device for monitoring the bobbin thread on stitch-forming

To scan the material being sewn (30, 31) in a sewing machine in an annular area around the presser foot, an annular lens system (25) is provided, which images a circle (33) concentrically surrounding the presser foot in the plane (A) of the material being sewn onto the light inlet ends of a likewise annularly arranged plurality of optical fibers (26). The optical fibers (26) lead, in an individual assignment, to the individual light-receiving elements of a photoelectric sensor line of a line camera, which sensor line can be read cyclically.

Device for optically scanning the material being sewn in a sewing machine

Stitch-forming machine with a transducer and a control device

Sewing machine with a thread monitor for the thread of the bobbin

The invention relates to a device for separating, delivering, and depositing material blanks, for use in the textile industry or the like which improves heat transfer to the gripping surface in a device in which the heating device is arranged in such a way that it is protected from external forces. The device comprises a heatable gripping plate, which has a gripping surface and an expansion chamber adjacent thereto, in which a refrigerant is able to expand and thus cool the gripping plate to below the freezing point so that a material blank will freeze onto said gripping surface. The side of the chamber opposite the gripping surface is closed by a nonmetallic intermediate plate whose surfaces are essentially parallel to said gripping surface and can be coated with metal, and which intermediate plate has a noncoated surface with an electrical heating resistor arranged therein and a metal-coated surface that is in metallic connection with a plurality of webs that form a bridge for heat transfer from the intermediate plate to the gripping surface.

Device for separating, delivering and depositing blanks

A sewing machine having a thread monitor associated with a bobbin mounted for rotation. The bobbin includes first and second reflecting surfaces associated with an inner side of a second bobbin flange, and first and second light outlet openings associated with a second bobbin flange. A light source is provided for directing light toward the reflecting surfaces. A light receiver is positioned so as to receive light emerging from the first and second outlet opening. The light receiver produces signals representing the light intensity received by the light receiver. A Schmitt trigger provides a pulse to a microprocessor coinciding with a revolution of the bobbin. For each revolution of the bobbin, an A/D converter converts signals received from the light receiver into digital signals which are compared. The digital signal having the maximum value for the revolution is stored in a memory and then compared with a subsequent maximum value. When the subsequent maximum value differs from the stored maximum value, a warning signal is generated by the microprocessor.

Sewing machine with thread monitor for the bobbin thread

A sewing machine with a lockstitch rotary hook containing a bobbin, has a thread monitor with which light signals of a radiation source are conducted to a light receiver via inlet and outlet openings in parts of the rotary hook and in at least one of the flanges of the bobbin. For determination of a predeterminable thread and length, the hub which connects the flanges of the bobbin comprises a truncated cone-shaped region, in the surface of which the outlet opening extending substantially parallel to the axis of the hub ends.

Thread monitor for the bottom thread in the bobbin of a sewing machine

Growing community of inventors

Enkenbach-Alsenborn, Germany

Bernhard Mertel