Durkoppwerke Gmbh

Wilhelm Stapel

Gunter Droste

Klaus-Dieter Seiler

Kurt Biermann

Gerhard Steppat

Rolf Ellermann

Klaus D Seiler

Michael Rosemann

Hermann Niehaus

Hans R Goebbels

Hans-Rolf Goebbels

A sewing machine has at least one rotating top thread hook, the hook enclosing a bobbin housing which accommodates a bottom thread. A spring bar is mounted in the base of the sewing machine and has a free end for bearing against the bobbin housing. The free end of the spring bar is displaceable by the top thread as it is being looped. To prevent unwanted displacement or oscillation of the spring bar, a cam is disposed in the base closely adjacent to the free end of the spring bar. The cam prevents displacement of the free end beyond a predetermined range of displacement.

Bobbin housing assembly in a sewing machine having at least one hook

A device in a sewing machine for applying a variable downward force to a presser bar. A guide lever engages the presser bar and in turn is urged downward by the force of a spring. The bottom of the spring is held fixed to a lock sleeve on the guide lever. The top of the spring is fixed to a sleeve on a shaft which is disposed vertically inside the spring. The shaft passes freely out the bottom of the spring and through the guide lever without engaging either of these. The shaft and thereby the top of the spring are urged downward by a controllable pneumatic device in order to set the compression of the spring and thereby the downward force applied to the pressure bar by the guide lever. The pneumatic device preferably includes a pair of separately controlled pneumatic pistions arranged in series for moving the shaft to at least two predetermined positions.

Sewing machine having a device actuable by a pressure medium for

A servo device for a multineedle sewing machine which includes two needle bars; driving and steop devices for said needle bars; devices for engaging and disengaging the two needle bars relative to the driving and stop devices; a feed-length adjustment device associated with at least one feed dog for the transport of the material being sewn; an adjustable thread tensioning device for the needle threads; devices for locking each needle bar selectively in its highest position; a positioning drive for the multineedle sewing machine; and a device including a position indicator attached to an arm shaft of the multineedle sewing machine, for adjusting the speed of rotation and positioning of the needle bars in predetermined positions. The servo device comprises a control system including a pair of electrical switches which respectively correspond to the needle bars, for controlling the engagement and disengagement of the needle bars relative to the driving and stop devices; a first setting device associated with the control system, for selectively interrupting the transport by the feed dog of the material being sewn; and a second setting device associated with the control system, for temporarily increasing a thread tensioning force exerted on the needle thread by the thread tensioning device.

Servo device for a multineedle sewing machine with engageable and

In a double-needle lock-stitch sewing machine, an assembly for arresting threads being drawn from the needles by an uptake stroke of a thread lever, thereby ensuring predetermined lengths of thread at the needles for an ensuing stitch, comprises a spring-loaded clamp disposed between the sewing lever and the needles. The clamp is periodically actuatable via a system of levers in the sewing-machine head by a cam mounted on the sewing-machine base and cooperating with a radial lug on a shaft driving a rotary thread gripper and bobbin holder. A spring-loaded plate engaging a pair of thread-tension control disks is pivotable by the lever system to release the disks upon actuation of the clamp. The clamp is particularly useful in controlling the length of a leading thread portion prior to beginning a sewing seam.

Controlled thread clamp device for needle threads

A bobbin and gripper assembly for a double-lock-stitch sewing machine has a stitch plate lying in a horizontal plane and a gripper rotatable in a horizontal plane below the stitch plate and receiving a bobbin housing. The latter is provided with a retaining finger which cooperates with abutments formed on the underside of the stitch plate to retain the bobbin housing against rotation with the gripper. In addition, the bobbin housing is held by a spring member which is effective to yieldably retard the bobbin against rotation in the direction of rotation of the gripper by friction therewith.

Gripper and bobbin assembly for double-lock-stitch sewing machine

A controlled braking device for the gripper-thread bobbin of a double lock-stitch sewing machine has a braking element which, by means of a brake piston or plunger in the axial bore of the spindle carrying the bobbin, is shiftable to engage the latter. The plunger is engaged by a rod reaching upwardly through an opening in the bottom of the spindle. The brake element is displaced laterally into engagement with the core of the bobbin or axially thereagainst.

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Bielefeld, Germany

Wilhelm Stapel