Operating instructions

27. Short Trimmer for the Looper Thread (579-112000)

After completion of the seam, the cutting movement of the needle

thread knife occurs. At the same time, the short trimmer is brought into

the base position for the looper thread. Thereby, the looper thread

slides from the blade of the knife.

Then the short trimmer is switched back. The looper thread is clamped

und cut through the switching back. In order to assure that the looper

thread is securely clamped at the seam beginning, the spring must

push the knife against the knife plate.

The clamping pressure must be set so that the looper thread is

securely held. With the clamping pressure set too high, the beginning

stitches are pulled together very strongly.

Note:

By screwing out the screw 7, the clamping pressure is decreased und

screwing in increases the clamping pressure.

The knife end position is set with the aid of the stop screw 9. Care is to be

taken thereby that parts of the needle hole are not covered by the knife.

Further, the knife holder 10 in its end position should not touch the needle

plate 11.

Setting the base position for the short trimmer:

–

Turn the sewing machine on

–

The short trimmer is in its base position

–

In the base position the knife should not be visible in the needle hole

und the knife holder 10 should not touch the needle plate 11.

–

Loosen lock nut 8.

–

Turn stop screw 9.

–

Tighten lock nut 8 again.

Setting the clamping pressure:

The clamping pressure should be set as low as possible.

–

By screwing in the screw 7, the clamping pressure is increased und

screwing out decreases the clamping pressure.

–

Incorrect clamping pressure or a needle plate too greatly soiled on

the inside lead to an unthreading of the looper thread.

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