Adjusting The Hook Thread Tension - Dürkopp Adler 271 Manuel D'utilisation

6.6

Adjusting the hook thread tension

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1
Attention, risk of injury!
Switch off the main switch.
Adjust the hook thread tension only when the sewing machine is
switched off.
Adjust the lopper thread tension
The hook thread tension must be adjusted such that a seam pattern is
formed as shown in Fig.a) of Chapter 6.
–
Given a recommended hook thread voltage of e.g. 30g, 15g
should be achieved with the brake spring 1 and 15g with the
tension spring 4.
–
The following rule applies for the basic setting for the tension
spring 4:
The bobbin case must sink slowly under it own weight. See
diagram in Chapter 6.5.
The brake spring 1 prevents the follow-up movement of the
bobbin during the thread cutting process.
For regulating the two tension values, proceed as follows:
–
Turn back the adjustment screw until the tension of the tension
spring 4 is completely relieved.
–
Adjust brake spring 1 by turning screw 2 such that half the
recommended hook thread tension value is rendered by the brake
spring.
Attention! Not required for classes: 271-140432, 271-140442,
273-140432.
–
Place the bobbin in the bobbin case body and thread the hook
thread (see Chapter 6.5).
–
Insert the bobbin case with bobbin in the looper.
–
Turn the hand wheel until the sewing machine executes a stitch.
–
Pull the hook thread on the top side of the needle hole with the
help of the needle thread.
–
Pull out the hook thread in seam direction at an angle of 45°.
Approx. half of the tension value should be perceptible.
Subsequently tighten the adjustment screw 3 up to the
recommended tension value.
4 3
2