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4.7 Setting the retaining spring of the hook thread
The retaining spring (1) holds the hook thread after having
performed the trimming. It is to be set in such a way that the
force necessary for pulling out the thread from the retaining
spring (1) is approximately equal to the force necessary for
pulling out the thread from the hook.
Caution! Danger of injury!
Switch off the main switch! Before starting the
setting operation, wait until the motor stops!
- Shape the retaining spring (1) in such a way that it fits close
with all its surface (without wedge) onto the moving trim-
ming knife (4).
- Shape the retaining spring in such a way that with mode-
rately tightened screws (2) it comes to lean against the
moving trimmer knife with a pre-load corresponding to the
force required to draw the thread out of the spring.
The pulling force is tested using a screwdriver according to
the illustration.
Caution!
The setting of the retaining spring (1) depends on
the setting of the hook thread tension and differs
then according to the respective sewing category.
4.8 Position of the lower thread - lefthand side
For an error-free function of the thread trimmer of the lower
thread on the lefthand side, it is necessary to have the thread
safely in the gap (7) see Figure.
Caution!
The incorrect position of the thread can cause the
thread non trimming .
- With each lower thread bobbin change in the hook, check
the correct thread position.
4.9 Setting the switching of electromagnets
The electromagnets of the trimming device and loosening of
the tensioner must work in accordance with the diagram. This
is ensured by setting the stopmotor (see the instructions for
use of the stopmotor).
1- 1. position of the needle (135
°
on the handwheel)
2- 2. position of the needle (64
°
on the handwheel)
3- position of stopping the tensioner (10
°
÷ 25
°
on the hand-
wheel)
4- movement of the pickup roller
5- current of the trimming device electromagnet
6- current of the tensioner loosening electromagnet
1
4
2
4
5
6
1
3
2
7
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