Durkoppwerke Gmbh

Durkopp Adler Aktiengesellschaft

Gerhard Riss

Heinz Lengel

Walter Schmidt

Detlef Jung

Heinz Niehaus

Rainer P Horst

Richard Fuerhoff

A device for the precise edge alignment and shift-free transfer of sewing material includes a feed device, a clamping carriage, and a swingably mounted stop straightedge. The material is manually placed in the feed device, between lowerable clamping tongues and a substantially flat support arm, in such a manner that its forward edge, which is to be aligned, is located in the vicinity of the stop straightedge, which is temporarily swung upward for aligning the material. The stop straightedge has a vacuum chamber which exerts suction on the material, and the suction action is further intensified by jets of air which emerge from the bottoms of the clamping tongues and are directed obliquely to the stop straightedge. In this way, the edge of the material is aligned precisely along the stop straightedge, without contact by the operator. Thereupon the aligned material is transferred forward, without shifting, to a position beneath the clamping levers of the clamping carriage.

Sewing system having a device for the precise edge alignment of sewing

A knife which is moveable vertically by a mover cooperates during the cutting process with a cutting plate which is mounted in a throat plate. A cutting edge of the knife is aligned parallel to an upper edge of the cutting plate so that these two cutting bodies momentarily contact each other over the full surface. In order to achieve a predetermined depth of penetration of the cutting edge into the cutting plate, which is made of visco-elastic plastic, the knife is first brought into an upper position by the mover. Then it is adjusted by a displacement member mounted in the mover. Its vertical position with respect to the cutting plate is displaced by a desired amount, while maintaining the parallel relationship of the cutting edge and the upper edge, regardless of their instantaneous position.

Sewing machine with an adjustable cutting device

In the sewing unit for the successive production of a number of stitch groups in a workpiece, a carriage supported slidably in two opposite directions on a frame and bearing a stitch group sewing machine. The sewing unit is periodically driven by a drive unit back and forth. A clamping device, slidably supported on the frame, is periodically coupled to the carriage by a clutch unit. The stitch group sewing operation takes place during the synchronous motion of the stitch group sewing machine and the clamping device. When the sewing operation is completed and the carriage is at rest, a pushing device attached to the frame pushes the clamping device, once it has been uncoupled from the carriage, in the opposite direction to its previously executed motion, back into its initial position.

Sewing machine apparatus for the succesive production of a number of

For producing properly shaped button holes in which the first zigzag stitches of the first button-hole caterpillar pattern are formed flat by covering the needle-side piece of thread which is held clamped, the button-hole sewing machine 1 is provided with a push device 41, a release device 58 and a shift mechanism 78. In this way, the thread cutting and clamping device 26 is moveable in synchronism with a material-presser basket 9 during its first phase of motion (I-II) which is directed parallel to the sewing-material transport direction NV. Furhtermore, towards the end of the first movement phase I-II, the needle-side piece of thread which is held clamped at the beginning of the sewing is automatically released by the release device 58 at a predetermined place so that it is completely covered by the following zigzag stitches of the first button-hole caterpillar pattern 92.

Button-hole sewing machine having a thread cutting and clamping device

A button feeding device includes a button alignment shaft having a longitudinal axis which is displaceable with respect to the longitudinal axis of the main drive shaft. The button alignment shaft and the main drive shaft are advantageously linked for rotation by a coil spring. The device has a pin holder which aligns the button and transfers it into a button clamp, a carriage being provided to move the pin holder over a substantially linear quadrangular path.

Button feeding device for button attaching machines

So-called raised buttonholes are sewn on a double-lock-stitch sewing machine with the fabric workpiece turned face down on the stitchplate of the sewing machine and the upper-thread tension being such that the interlocking loops of the upper and lower threads lie upon the downwardly facing side of the workpiece. According to the invention, the upper-thread tension at the end of a buttonhole-stitching cycle for the fastening stitch is increased above the lower-thread tension temporarily so that the interlocking loops of the upper and lower threads during this last fastening stitch lie within the thickness of the material or on the upper face of the downwardly turned workpiece.

Method of and apparatus for the production of button-holes on a double

A method of and apparatus for the sewing of a succession of stitchgroups on a workpiece and for the feeding of a new workpiece into sewing position, e.g. for producing buttonholes on shirtfronts. The buttonholes are formed by linearly displacing a buttonhole stitching machine stepwise relative to a clamped edge of a fabric workpiece, and a second clamp adjacent the first is provided to retain a second workpiece in position. When the first row of buttonholes is completed upon movement of the machine in one direction, the fabric workpiece, which has been buttonholed, is released, the second fabric is engaged and brought into position, and the sewing machine is displaced in the opposite direction to form a respective row of buttonholes on the new fabric.

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Bielefeld, Germany

Gerhard Riss